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Klement K, Brückner M, Bernkopf DB. Phosphorylation of axin within biomolecular condensates counteracts its tankyrase-mediated degradation. J Cell Sci 2023; 136:jcs261214. [PMID: 37721093 PMCID: PMC10652037 DOI: 10.1242/jcs.261214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 09/08/2023] [Indexed: 09/19/2023] Open
Abstract
Axin (also known as AXIN1) is a central negative regulator of the proto-oncogenic Wnt/β-catenin signaling pathway, as axin condensates provide a scaffold for the assembly of a multiprotein complex degrading β-catenin. Axin, in turn, is degraded through tankyrase. Consequently, tankyrase small-molecule inhibitors block Wnt signaling by stabilizing axin, revealing potential for cancer therapy. Here, we discovered that axin is phosphorylated by casein kinase 1 alpha 1 (CSNK1A1, also known as CK1α) at an N-terminal casein kinase 1 consensus motif, and that this phosphorylation is antagonized by the catalytic subunit alpha of protein phosphatase 1 (PPP1CA, hereafter referred to as PP1). Axin condensates promoted phosphorylation by enriching CK1α over PP1. Importantly, the phosphorylation took place within the tankyrase-binding site, electrostatically and/or sterically hindering axin-tankyrase interaction, and counteracting tankyrase-mediated degradation of axin. Thus, the presented data propose a novel mechanism regulating axin stability, with implications for Wnt signaling, cancer therapy and self-organization of biomolecular condensates.
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Affiliation(s)
- Katharina Klement
- Experimental Medicine II, Nikolaus-Fiebiger-Center, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Martina Brückner
- Experimental Medicine II, Nikolaus-Fiebiger-Center, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Dominic B. Bernkopf
- Experimental Medicine II, Nikolaus-Fiebiger-Center, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany
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2
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Peris I, Romero-Murillo S, Vicente C, Narla G, Odero MD. Regulation and role of the PP2A-B56 holoenzyme family in cancer. Biochim Biophys Acta Rev Cancer 2023; 1878:188953. [PMID: 37437699 DOI: 10.1016/j.bbcan.2023.188953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 07/07/2023] [Accepted: 07/08/2023] [Indexed: 07/14/2023]
Abstract
Protein phosphatase 2A (PP2A) inactivation is common in cancer, leading to sustained activation of pro-survival and growth-promoting pathways. PP2A consists of a scaffolding A-subunit, a catalytic C-subunit, and a regulatory B-subunit. The functional complexity of PP2A holoenzymes arises mainly through the vast repertoire of regulatory B-subunits, which determine both their substrate specificity and their subcellular localization. Therefore, a major challenge for developing more effective therapeutic strategies for cancer is to identify the specific PP2A complexes to be targeted. Of note, the development of small molecules specifically directed at PP2A-B56α has opened new therapeutic avenues in both solid and hematological tumors. Here, we focus on the B56/PR61 family of PP2A regulatory subunits, which have a central role in directing PP2A tumor suppressor activity. We provide an overview of the mechanisms controlling the formation and regulation of these complexes, the pathways they control, and the mechanisms underlying their deregulation in cancer.
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Affiliation(s)
- Irene Peris
- Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain; Centro de Investigación Médica Aplicada (CIMA), University of Navarra, Pamplona, Spain; Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain.
| | - Silvia Romero-Murillo
- Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain; Centro de Investigación Médica Aplicada (CIMA), University of Navarra, Pamplona, Spain
| | - Carmen Vicente
- Centro de Investigación Médica Aplicada (CIMA), University of Navarra, Pamplona, Spain; Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
| | - Goutham Narla
- Division of Genetic Medicine, Department of Internal Medicine, The University of Michigan Medical School, Ann Arbor, MI, USA
| | - Maria D Odero
- Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain; Centro de Investigación Médica Aplicada (CIMA), University of Navarra, Pamplona, Spain; Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain; CIBERONC, Instituto de Salud Carlos III, Madrid, Spain.
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3
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Guo Y, Bao J, Lin D, Hong K, Cen K, Sun J, Wang Z, Wu Z. Novel immune checkpoint-related gene model to predict prognosis and treatment responsiveness in low-grade gliomas. Heliyon 2023; 9:e20178. [PMID: 37809899 PMCID: PMC10559968 DOI: 10.1016/j.heliyon.2023.e20178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 09/05/2023] [Accepted: 09/13/2023] [Indexed: 10/10/2023] Open
Abstract
Recently, studies have shown that immune checkpoint-related genes (ICGs) are instrumental in maintaining immune homeostasis and can be regarded as potential therapeutic targets. However, the prognostic applications of ICGs require further elucidation in low-grade glioma (LGG) cases. In the present study, a unique prognostic gene signature in LGG has been identified and validated as well based on ICGs as a means of facilitating clinical decision-making. The RNA-seq data as well as corresponding clinical data of LGG samples have been retrieved utilizing the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. ICG-defined non-negative matrix factorization (NMF) clustering was performed to categorize patients with LGG into two molecular subtypes with different prognoses, clinical traits, and immune microenvironments. In the TCGA database, a signature integrating 8 genes has been developed utilizing the LASSO Cox method and validated in the GEO database. The signature developed is superior to other well-recognized signatures in terms of predicting the survival probability of patients with LGG. This 8-gene signature was then subsequently applied to categorize patients into high- and low-risk groups, and differences between them in terms of gene alteration frequency were observed. There were remarkable variations in IDH1 (91% and 64%) across low-as well as high-risk groups. Additionally, various analyses like function enrichment, tumor immune microenvironment, and chemotherapy drug sensitivity revealed significant variations across high- and low-risk populations. Overall, this 8-gene signature may function as a useful tool for prognosis and immunotherapy outcome predictions among LGG patients.
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Affiliation(s)
- Yangyang Guo
- Department of Neurosurgery, The First Affiliated Hospital of Ningbo University, Haishu District, Ningbo, 315010, Zhejiang, People's Republic of China
| | - Jingxia Bao
- Department of Breast Surgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang, People's Republic of China
| | - Danfeng Lin
- Department of Breast Surgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang, People's Republic of China
| | - Kai Hong
- Department of Neurosurgery, The First Affiliated Hospital of Ningbo University, Haishu District, Ningbo, 315010, Zhejiang, People's Republic of China
| | - Kenan Cen
- The Affiliated Hospital of Medical School of Ningbo University, Jiangbei District, Ningbo, 315020, Zhejiang, People's Republic of China
| | - Jie Sun
- Department of Neurosurgery, The First Affiliated Hospital of Ningbo University, Haishu District, Ningbo, 315010, Zhejiang, People's Republic of China
| | - Zhepei Wang
- Department of Neurosurgery, The First Affiliated Hospital of Ningbo University, Haishu District, Ningbo, 315010, Zhejiang, People's Republic of China
| | - Zhixuan Wu
- Department of Breast Surgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang, People's Republic of China
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4
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Hsiao KC, Ruan SY, Chen SM, Lai TY, Chan RH, Zhang YM, Chu CA, Cheng HC, Tsai HW, Tu YF, Law BK, Chang TT, Chow NH, Chiang CW. The B56γ3-containing protein phosphatase 2A attenuates p70S6K-mediated negative feedback loop to enhance AKT-facilitated epithelial-mesenchymal transition in colorectal cancer. Cell Commun Signal 2023; 21:172. [PMID: 37430297 DOI: 10.1186/s12964-023-01182-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 06/04/2023] [Indexed: 07/12/2023] Open
Abstract
BACKGROUND Protein phosphatase 2A (PP2A) is one of the major protein phosphatases in eukaryotic cells and is essential for cellular homeostasis. PP2A is a heterotrimer comprising the dimeric AC core enzyme and a highly variable regulatory B subunit. Distinct B subunits help the core enzyme gain full activity toward specific substrates and contribute to diverse cellular roles of PP2A. PP2A has been thought to play a tumor suppressor and the B56γ3 regulatory subunit was shown to play a key tumor suppressor regulatory subunit of PP2A. Nevertheless, we uncovered a molecular mechanism of how B56γ3 may act as an oncogene in colorectal cancer (CRC). METHODS Polyclonal pools of CRC cells with stable B56γ3 overexpression or knockdown were generated by retroviral or lentiviral infection and subsequent drug selection. Co-immunoprecipitation(co-IP) and in vitro pull-down analysis were applied to analyze the protein-protein interaction. Transwell migration and invasion assays were applied to investigate the role of B56γ3 in affecting motility and invasive capability of CRC cells. The sensitivity of CRC cells to 5-fluorouracil (5-FU) was analyzed using the PrestoBlue reagent assay for cell viability. Immunohistochemistry (IHC) was applied to investigate the expression levels of phospho-AKT and B56γ3 in paired tumor and normal tissue specimens of CRC. DataSets of TCGA and GEO were analyzed to investigate the correlation of B56γ3 expression with overall survival rates of CRC patients. RESULTS We showed that B56γ3 promoted epithelial-mesenchymal transition (EMT) and reduced the sensitivity of CRC cells to 5-FU through upregulating AKT activity. Mechanistically, B56γ3 upregulates AKT activity by targeting PP2A to attenuate the p70S6K-mediated negative feedback loop regulation on PI3K/AKT activation. B56γ3 was highly expressed and positively correlated with the level of phospho-AKT in tumor tissues of CRC. Moreover, high B56γ3 expression is associated with poor prognosis of a subset of patients with CRC. CONCLUSIONS Our finding reveals that the B56γ3 regulatory subunit-containing PP2A plays an oncogenic role in CRC cells by sustaining AKT activation through suppressing p70S6K activity and suggests that the interaction between B56γ3 and p70S6K may serve as a therapeutic target for CRC. Video Abstract.
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Affiliation(s)
- Kai-Ching Hsiao
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
| | - Siou-Ying Ruan
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
| | - Shih-Min Chen
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
| | - Tai-Yu Lai
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
| | - Ren-Hao Chan
- Department of Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
| | - Yan-Ming Zhang
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
| | - Chien-An Chu
- Department of Pathology, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
| | - Hung-Chi Cheng
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
| | - Hung-Wen Tsai
- Department of Pathology, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
| | - Yi-Fang Tu
- Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
| | - Brian K Law
- Department of Pharmacology and Therapeutics and the UF-Health Cancer Center, University of Florida, Gainesville, FL, 32610, USA
| | - Ting-Tsung Chang
- Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
| | - Nan-Haw Chow
- Department of Pathology, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
| | - Chi-Wu Chiang
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC.
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC.
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5
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Avelar RA, Armstrong AJ, Carvette G, Gupta R, Puleo N, Colina JA, Joseph P, Sobeck AM, O'Connor CM, Raines B, Gandhi A, Dziubinski ML, Ma DS, Resnick K, Singh S, Zanotti K, Nagel C, Waggoner S, Thomas DG, Skala SL, Zhang J, Narla G, DiFeo A. Small-Molecule-Mediated Stabilization of PP2A Modulates the Homologous Recombination Pathway and Potentiates DNA Damage-Induced Cell Death. Mol Cancer Ther 2023; 22:599-615. [PMID: 36788429 PMCID: PMC10157366 DOI: 10.1158/1535-7163.mct-21-0880] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 05/17/2022] [Accepted: 02/09/2023] [Indexed: 02/16/2023]
Abstract
High-grade serous carcinoma (HGSC) is the most common and lethal ovarian cancer subtype. PARP inhibitors (PARPi) have become the mainstay of HGSC-targeted therapy, given that these tumors are driven by a high degree of genomic instability (GI) and homologous recombination (HR) defects. Nonetheless, approximately 30% of patients initially respond to treatment, ultimately relapsing with resistant disease. Thus, despite recent advances in drug development and an increased understanding of genetic alterations driving HGSC progression, mortality has not declined, highlighting the need for novel therapies. Using a small-molecule activator of protein phosphatase 2A (PP2A; SMAP-061), we investigated the mechanism by which PP2A stabilization induces apoptosis in patient-derived HGSC cells and xenograft (PDX) models alone or in combination with PARPi. We uncovered that PP2A genes essential for cellular transformation (B56α, B56γ, and PR72) and basal phosphatase activity (PP2A-A and -C) are heterozygously lost in the majority of HGSC. Moreover, loss of these PP2A genes correlates with worse overall patient survival. We show that SMAP-061-induced stabilization of PP2A inhibits the HR output by targeting RAD51, leading to chronic accumulation of DNA damage and ultimately apoptosis. Furthermore, combination of SMAP-061 and PARPi leads to enhanced apoptosis in both HR-proficient and HR-deficient HGSC cells and PDX models. Our studies identify PP2A as a novel regulator of HR and indicate PP2A modulators as a therapeutic therapy for HGSC. In summary, our findings further emphasize the potential of PP2A modulators to overcome PARPi insensitivity, given that targeting RAD51 presents benefits in overcoming PARPi resistance driven by BRCA1/2 mutation reversions.
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Affiliation(s)
- Rita A. Avelar
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
| | | | - Gracie Carvette
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
| | - Riya Gupta
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
| | - Noah Puleo
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
| | - Jose A. Colina
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
| | - Peronne Joseph
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio
| | - Alexander M. Sobeck
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
| | - Caitlin M. O'Connor
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
- Department of Internal Medicine, Genetic Medicine, University of Michigan, Ann Arbor, Michigan
| | - Brynne Raines
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
- Department of Internal Medicine, Genetic Medicine, University of Michigan, Ann Arbor, Michigan
| | - Agharnan Gandhi
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
| | - Michele L. Dziubinski
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
| | - Daniel S. Ma
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio
| | | | | | | | | | | | - Daffyd G. Thomas
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
| | | | - Junran Zhang
- Department of Radiation Oncology, Ohio State University, Columbus, Ohio
| | - Goutham Narla
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
- Department of Internal Medicine, Genetic Medicine, University of Michigan, Ann Arbor, Michigan
| | - Analisa DiFeo
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, Michigan
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6
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Marin GH, Murail S, Andrini L, Garcia M, Loisel S, Tuffery P, Rebollo A. In Silico and In Vivo Studies of a Tumor-Penetrating and Interfering Peptide with Antitumoral Effect on Xenograft Models of Breast Cancer. Pharmaceutics 2023; 15:pharmaceutics15041180. [PMID: 37111665 PMCID: PMC10142558 DOI: 10.3390/pharmaceutics15041180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 03/09/2023] [Accepted: 04/05/2023] [Indexed: 04/29/2023] Open
Abstract
The combination of a tumor-penetrating peptide (TPP) with a peptide able to interfere with a given protein-protein interaction (IP) is a promising strategy with potential clinical application. Little is known about the impact of fusing a TPP with an IP, both in terms of internalization and functional effect. Here, we analyze these aspects in the context of breast cancer, targeting PP2A/SET interaction, using both in silico and in vivo approaches. Our results support the fact that state-of-the-art deep learning approaches developed for protein-peptide interaction modeling can reliably identify good candidate poses for the IP-TPP in interaction with the Neuropilin-1 receptor. The association of the IP with the TPP does not seem to affect the ability of the TPP to bind to Neuropilin-1. Molecular simulation results suggest that peptide IP-GG-LinTT1 in a cleaved form interacts with Neuropilin-1 in a more stable manner and has a more helical secondary structure than the cleaved IP-GG-iRGD. Surprisingly, in silico investigations also suggest that the non-cleaved TPPs can bind the Neuropilin-1 in a stable manner. The in vivo results using xenografts models show that both bifunctional peptides resulting from the combination of the IP and either LinTT1 or iRGD are effective against tumoral growth. The peptide iRGD-IP shows the highest stability to serum proteases degradation while having the same antitumoral effect as Lin TT1-IP, which is more sensitive to proteases degradation. Our results support the development of the TPP-IP strategy as therapeutic peptides against cancer.
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Affiliation(s)
- Gustavo H Marin
- Department of Pharmacology/Histology and Embryology, FMC, National University of La Plata, CONICET, La Plata 1900, Argentina
| | - Samuel Murail
- BFA, Université Paris Cite, CNRS UMR 8251, Inserm U1133, 75013 Paris, France
| | - Laura Andrini
- Department of Pharmacology/Histology and Embryology, FMC, National University of La Plata, CONICET, La Plata 1900, Argentina
| | - Marcela Garcia
- Department of Pharmacology/Histology and Embryology, FMC, National University of La Plata, CONICET, La Plata 1900, Argentina
| | | | - Pierre Tuffery
- BFA, Université Paris Cite, CNRS UMR 8251, Inserm U1133, 75013 Paris, France
| | - Angelita Rebollo
- Faculté de Pharmacie, UTCBS, Université Paris Cite, Inserm U1267, 75006 Paris, France
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7
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Zou W, Imperiale MJ. Regulation of Virus Replication by BK Polyomavirus Small T Antigen. J Virol 2023; 97:e0007723. [PMID: 36916919 PMCID: PMC10062181 DOI: 10.1128/jvi.00077-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 02/20/2023] [Indexed: 03/16/2023] Open
Abstract
Polyomavirus small T antigen (tAg) plays important roles in regulating viral replication, the innate immune response, apoptosis, and transformation for SV40, Merkel cell polyomavirus (MCPyV), murine polyomavirus (MuPyV), and JC polyomavirus (JCPyV). However, the function of BK polyomavirus (BKPyV) tAg has been much less studied. Here, we constructed mutant viruses that do not express tAg, and we showed that, in contrast with other polyomaviruses, BKPyV tAg inhibits large T antigen (TAg) gene expression and viral DNA replication. However, this occurs only in an archetype viral background. We also observed that the transduction of cells with a lentivirus-expressing BKPyV tAg kills the cells. We further discovered that BKPyV tAg interacts not only with PP2A A and C subunits, as has been demonstrated for other polyomavirus tAg proteins, but also with PP2A B''' subunit members. Knocking down either of two B''' subunits, namely STRN or STRN3, mimics the phenotype of the tAg mutant virus. However, a virus containing a point mutation in the PP2A binding domain of tAg only partially affected virus TAg expression and DNA replication. These results indicate that BKPyV tAg downregulates viral gene expression and DNA replication and that this occurs in part through interactions with PP2A. IMPORTANCE BK polyomavirus is a virus that establishes a lifelong infection of the majority of people. The infection usually does not cause any clinical symptoms, but, in transplant recipients whose immune systems have been suppressed, unchecked virus replication can cause severe disease. In this study, we show that a viral protein called small T antigen is one of the ways that the virus can persist without high levels of replication. Understanding which factors control viral replication enhances our knowledge of the virus life cycle and could lead to potential interventions for these patients.
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Affiliation(s)
- Wei Zou
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Michael J. Imperiale
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
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8
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Pavic K, Gupta N, Omella JD, Derua R, Aakula A, Huhtaniemi R, Määttä JA, Höfflin N, Okkeri J, Wang Z, Kauko O, Varjus R, Honkanen H, Abankwa D, Köhn M, Hytönen VP, Xu W, Nilsson J, Page R, Janssens V, Leitner A, Westermarck J. Structural mechanism for inhibition of PP2A-B56α and oncogenicity by CIP2A. Nat Commun 2023; 14:1143. [PMID: 36854761 PMCID: PMC9974998 DOI: 10.1038/s41467-023-36693-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 02/09/2023] [Indexed: 03/02/2023] Open
Abstract
The protein phosphatase 2A (PP2A) heterotrimer PP2A-B56α is a human tumour suppressor. However, the molecular mechanisms inhibiting PP2A-B56α in cancer are poorly understood. Here, we report molecular level details and structural mechanisms of PP2A-B56α inhibition by an oncoprotein CIP2A. Upon direct binding to PP2A-B56α trimer, CIP2A displaces the PP2A-A subunit and thereby hijacks both the B56α, and the catalytic PP2Ac subunit to form a CIP2A-B56α-PP2Ac pseudotrimer. Further, CIP2A competes with B56α substrate binding by blocking the LxxIxE-motif substrate binding pocket on B56α. Relevant to oncogenic activity of CIP2A across human cancers, the N-terminal head domain-mediated interaction with B56α stabilizes CIP2A protein. Functionally, CRISPR/Cas9-mediated single amino acid mutagenesis of the head domain blunted MYC expression and MEK phosphorylation, and abrogated triple-negative breast cancer in vivo tumour growth. Collectively, we discover a unique multi-step hijack and mute protein complex regulation mechanism resulting in tumour suppressor PP2A-B56α inhibition. Further, the results unfold a structural determinant for the oncogenic activity of CIP2A, potentially facilitating therapeutic modulation of CIP2A in cancer and other diseases.
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Affiliation(s)
- Karolina Pavic
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, 20520, Turku, Finland
- Cancer Cell Biology and Drug Discovery Group, Department of Life Sciences and Medicine, University of Luxembourg, Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Nikhil Gupta
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, 20520, Turku, Finland
| | - Judit Domènech Omella
- Laboratory of Protein Phosphorylation & Proteomics, Department of Cellular & Molecular Medicine, University of Leuven (KU Leuven), B-3000, Leuven, Belgium
| | - Rita Derua
- Laboratory of Protein Phosphorylation & Proteomics, Department of Cellular & Molecular Medicine, University of Leuven (KU Leuven), B-3000, Leuven, Belgium
- SyBioMa, University of Leuven (KU Leuven), B-3000, Leuven, Belgium
| | - Anna Aakula
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, 20520, Turku, Finland
| | - Riikka Huhtaniemi
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, 20520, Turku, Finland
| | - Juha A Määttä
- Faculty of Medicine and Health Technology, Tampere University, 33520 Tampere, Finland and Fimlab Laboratories, 33520, Tampere, Finland
| | - Nico Höfflin
- Faculty of Biology, Institute of Biology III, University of Freiburg, 79104, Freiburg, Germany
| | - Juha Okkeri
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, 20520, Turku, Finland
| | - Zhizhi Wang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Otto Kauko
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, 20520, Turku, Finland
| | - Roosa Varjus
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, 20520, Turku, Finland
| | - Henrik Honkanen
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, 20520, Turku, Finland
| | - Daniel Abankwa
- Cancer Cell Biology and Drug Discovery Group, Department of Life Sciences and Medicine, University of Luxembourg, Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Maja Köhn
- Faculty of Biology, Institute of Biology III, University of Freiburg, 79104, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Vesa P Hytönen
- Faculty of Medicine and Health Technology, Tampere University, 33520 Tampere, Finland and Fimlab Laboratories, 33520, Tampere, Finland
| | - Wenqing Xu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Jakob Nilsson
- The Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen, Denmark
| | - Rebecca Page
- Department of Chemistry and Biochemistry University of Arizona, Tucson, AZ, USA
| | - Veerle Janssens
- Laboratory of Protein Phosphorylation & Proteomics, Department of Cellular & Molecular Medicine, University of Leuven (KU Leuven), B-3000, Leuven, Belgium
| | - Alexander Leitner
- Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, 8093, Zurich, Switzerland
| | - Jukka Westermarck
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, 20520, Turku, Finland.
- Institute of Biomedicine, University of Turku, 20520, Turku, Finland.
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9
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Brauer BL, Wiredu K, Gerber SA, Kettenbach AN. Evaluation of Quantification and Normalization Strategies for Phosphoprotein Phosphatase Affinity Proteomics: Application to Breast Cancer Signaling. J Proteome Res 2023; 22:47-61. [PMID: 36448918 PMCID: PMC10625046 DOI: 10.1021/acs.jproteome.2c00465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Accurate quantification of proteomics data is essential for revealing and understanding biological signaling processes. We have recently developed a chemical proteomic strategy termed phosphatase inhibitor beads and mass spectrometry (PIB-MS) to investigate endogenous phosphoprotein phosphatase (PPP) dephosphorylation signaling. Here, we compare the robustness and reproducibility of status quo quantification methods for optimal performance and ease of implementation. We then apply PIB-MS to an array of breast cancer cell lines to determine differences in PPP signaling between subtypes. Breast cancer, a leading cause of cancer death in women, consists of three main subtypes: estrogen receptor-positive (ER+), human epidermal growth factor receptor two positive (HER2+), and triple-negative (TNBC). Although there are effective treatment strategies for ER+ and HER2+ subtypes, tumors become resistant and progress. Furthermore, TNBC has few targeted therapies. Therefore, there is a need to identify new approaches for treating breast cancers. Using PIB-MS, we distinguished TNBC from non-TNBC based on subtype-specific PPP holoenzyme composition. In addition, we identified an increase in PPP interactions with Hippo pathway proteins in TNBC. These interactions suggest that phosphatases in TNBC play an inhibitory role on the Hippo pathway and correlate with increased expression of YAP/TAZ target genes both in TNBC cell lines and in TNBC patients.
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Affiliation(s)
- Brooke L. Brauer
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH
| | - Kwame Wiredu
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH
| | - Scott A. Gerber
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH
- Dartmouth Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, NH
| | - Arminja N. Kettenbach
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH
- Dartmouth Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, NH
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10
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Haanen TJ, O'Connor CM, Narla G. Biased holoenzyme assembly of protein phosphatase 2A (PP2A): From cancer to small molecules. J Biol Chem 2022; 298:102656. [PMID: 36328247 PMCID: PMC9707111 DOI: 10.1016/j.jbc.2022.102656] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 10/25/2022] [Accepted: 10/27/2022] [Indexed: 11/06/2022] Open
Abstract
Protein phosphatase 2A (PP2A) is a family of serine threonine phosphatases responsible for regulating protein phosphorylation, thus opposing the activity of cellular kinases. PP2A is composed of a catalytic subunit (PP2A Cα/β) and scaffolding subunit (PP2A Aα/β) and various substrate-directing B regulatory subunits. PP2A biogenesis is regulated at multiple levels. For example, the sequestration of the free catalytic subunit during the process of biogenesis avoids promiscuous phosphatase activity. Posttranslational modifications of PP2A C direct PP2A heterotrimeric formation. Additionally, PP2A functions as a haploinsufficient tumor suppressor, where attenuated PP2A enzymatic activity creates a permissive environment for oncogenic transformation. Recent work studying PP2A in cancer showed that its role in tumorigenesis is more nuanced, with some holoenzymes being tumor suppressive, while others are required for oncogenic transformation. In cancer biology, PP2A function is modulated through various mechanisms including the displacement of specific B regulatory subunits by DNA tumor viral antigens, by recurrent mutations, and through loss of carboxymethyl-sensitive heterotrimeric complexes. In aggregate, these alterations bias PP2A activity away from its tumor suppressive functions and toward oncogenic ones. From a therapeutic perspective, molecular glues and disruptors present opportunities for both the selective stabilization of tumor-suppressive holoenzymes and disruption of holoenzymes that are pro-oncogenic. Collectively, these approaches represent an attractive cancer therapy for a wide range of tumor types. This review will discuss the mechanisms by which PP2A holoenzyme formation is dysregulated in cancer and the current therapies that are aimed at biasing heterotrimer formation of PP2A for the treatment of cancer.
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Affiliation(s)
- Terrance J Haanen
- Division of Genetic Medicine, Department of Internal Medicine, The University of Michigan, Ann Arbor, Michigan, USA
| | - Caitlin M O'Connor
- Division of Genetic Medicine, Department of Internal Medicine, The University of Michigan, Ann Arbor, Michigan, USA
| | - Goutham Narla
- Division of Genetic Medicine, Department of Internal Medicine, The University of Michigan, Ann Arbor, Michigan, USA.
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11
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Gu S, Jiang M, Zhang B. Microcystin-LR in Primary Liver Cancers: An Overview. Toxins (Basel) 2022; 14:toxins14100715. [PMID: 36287983 PMCID: PMC9611980 DOI: 10.3390/toxins14100715] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 09/29/2022] [Accepted: 10/17/2022] [Indexed: 12/01/2022] Open
Abstract
The cyanobacterial blooms produced by eutrophic water bodies have become a serious environmental issue around the world. After cellular lysing or algaecide treatment, microcystins (MCs), which are regarded as the most frequently encountered cyanobacterial toxins in fresh water, are released into water. Among all the variants of MCs, MC-LR has been widely studied due to its severe hepatotoxicity. Since 1992, various studies have identified the important roles of MC-LR in the origin and progression of primary liver cancers (PLCs), although few reviews have focused on it. Therefore, this review aims to summarize the major achievements and shortcomings observed in the past few years. Based on the available literature, the mechanisms of how MC-LR induces or promotes PLCs are elucidated in this review. This review aims to enhance our understanding of the role that MC-LR plays in PLCs and provides a rational approach for future applications.
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Affiliation(s)
- Shen Gu
- Key Laboratory of Clinical Cancer Pharmacology and Toxicology Research of Zhejiang Province, Affiliated Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou 310006, China
- Translational Medicine Research Center, Affiliated Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou 310006, China
- Correspondence: ; Tel.: +86-0571-56007664
| | - Mingxuemei Jiang
- Institute of Scientific and Technical Information of Zhejiang Province, Hangzhou 310001, China
| | - Bo Zhang
- Key Laboratory of Clinical Cancer Pharmacology and Toxicology Research of Zhejiang Province, Affiliated Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou 310006, China
- Translational Medicine Research Center, Affiliated Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou 310006, China
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12
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Ripamonti M, Lamarca A, Davey NE, Tonoli D, Surini S, de Curtis I. A functional interaction between liprin-α1 and B56γ regulatory subunit of protein phosphatase 2A supports tumor cell motility. Commun Biol 2022; 5:1025. [PMID: 36171301 PMCID: PMC9519923 DOI: 10.1038/s42003-022-03989-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 09/13/2022] [Indexed: 11/25/2022] Open
Abstract
Scaffold liprin-α1 is required to assemble dynamic plasma membrane-associated platforms (PMAPs) at the front of migrating breast cancer cells, to promote protrusion and invasion. We show that the N-terminal region of liprin-α1 contains an LxxIxE motif interacting with B56 regulatory subunits of serine/threonine protein phosphatase 2A (PP2A). The specific interaction of B56γ with liprin-α1 requires an intact motif, since two point mutations strongly reduce the interaction. B56γ mediates the interaction of liprin-α1 with the heterotrimeric PP2A holoenzyme. Most B56γ protein is recovered in the cytosolic fraction of invasive MDA-MB-231 breast cancer cells, where B56γ is complexed with liprin-α1. While mutation of the short linear motif (SLiM) does not affect localization of liprin-α1 to PMAPs, localization of B56γ at these sites specifically requires liprin-α1. Silencing of B56γ or liprin-α1 inhibits to similar extent cell spreading on extracellular matrix, invasion, motility and lamellipodia dynamics in migrating MDA-MB-231 cells, suggesting that B56γ/PP2A is a novel component of the PMAPs machinery regulating tumor cell motility. In this direction, inhibition of cell spreading by silencing liprin-α1 is not rescued by expression of B56γ binding-defective liprin-α1 mutant. We propose that liprin-α1-mediated recruitment of PP2A via B56γ regulates cell motility by controlling protrusion in migrating MDA-MB-231 cells.
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Affiliation(s)
- Marta Ripamonti
- San Raffaele Scientific Institute and Università Vita-Salute San Raffaele, Milano, Italy
| | - Andrea Lamarca
- San Raffaele Scientific Institute and Università Vita-Salute San Raffaele, Milano, Italy
| | - Norman E Davey
- Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, UK
| | - Diletta Tonoli
- San Raffaele Scientific Institute and Università Vita-Salute San Raffaele, Milano, Italy
| | - Sara Surini
- San Raffaele Scientific Institute and Università Vita-Salute San Raffaele, Milano, Italy
| | - Ivan de Curtis
- San Raffaele Scientific Institute and Università Vita-Salute San Raffaele, Milano, Italy.
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13
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Dorgham K, Murail S, Tuffery P, Savier E, Bravo J, Rebollo A. Binding and Kinetic Analysis of Human Protein Phosphatase PP2A Interactions with Caspase 9 Protein and the Interfering Peptide C9h. Pharmaceutics 2022; 14:pharmaceutics14102055. [PMID: 36297489 PMCID: PMC9609871 DOI: 10.3390/pharmaceutics14102055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 09/22/2022] [Accepted: 09/23/2022] [Indexed: 11/16/2022] Open
Abstract
The serine/threonine phosphatase PP2A and the cysteine protease Caspase 9 are two proteins involved in physiological and pathological processes, including cancer and apoptosis. We previously demonstrated the interaction between Caspase 9 and PP2A and identified the C9h peptide, corresponding to the binding site of Caspase 9 to PP2A. This interfering peptide can modulate Caspase 9/PP2A interaction leading to a strong therapeutic effect in vitro and in vivo in mouse models of tumor progression. In this manuscript, we investigate (I) the peptide binding to PP2A combining docking with molecular dynamics and (II) the secondary structure of the peptide using CD spectroscopy. Additionally, we compare the binding affinity, using biolayer interferometry, of the wild-type protein PP2A with Caspase 9 and vice versa to that observed between the PP2A protein and the interfering peptide C9h. This result strongly encourages the use of peptides as new therapeutics against cancer, as shown for the C9h peptide already in clinical trial.
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Affiliation(s)
- Karim Dorgham
- Faculty of Medicine, Sorbonne Université, Inserm, CIMI Paris, 91, bd de l’hôpital, 75013 Paris, France
| | - Samuel Murail
- BFA, Université Paris Cité, Inserm 1133, 75013 Paris, France
| | - Pierre Tuffery
- BFA, Université Paris Cité, Inserm 1133, 75013 Paris, France
| | - Eric Savier
- AP-HP, Sorbonne Université, CRSA, 75013 Paris, France
| | - Jeronimo Bravo
- Instituto de Biomedicina de Valencia IBV-CSIC, Jaime Roig, 11, 46010 Valencia, Spain
| | - Angelita Rebollo
- Faculty of Pharmacy, UTCBS, Université Paris Cité, Inserm 1267, 75006 Paris, France
- Correspondence:
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14
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Takahashi T, Ichikawa H, Okayama Y, Seki M, Hijikata T. SV40 miR-S1 and Cellular miR-1266 Sequester Each Other from Their Targets, Enhancing Telomerase Activity and Viral Replication. Noncoding RNA 2022; 8:ncrna8040057. [PMID: 36005825 PMCID: PMC9413689 DOI: 10.3390/ncrna8040057] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 07/24/2022] [Accepted: 07/26/2022] [Indexed: 11/16/2022] Open
Abstract
Virus-encoded microRNAs (miRNAs) target viral and host mRNAs to repress protein production from viral and host genes, and regulate viral persistence, cell transformation, and evasion of the immune system. The present study demonstrated that simian virus 40 (SV40)-encoded miRNA miR-S1 targets a cellular miRNA miR-1266 to derepress their respective target proteins, namely, T antigens (Tags) and telomerase reverse transcriptase (TERT). An in silico search for cellular miRNAs to interact with viral miR-S1 yielded nine potential miRNAs, five of which, including miR-1266, were found to interact with miR-S1 in dual-luciferase tests employing reporter plasmids containing the miRNA sequences with miR-S1. Intracellular bindings of miR-1266 to miR-S1 were also verified by the pull-down assay. These miRNAs were recruited into the Ago2-associated RNA-induced silencing complex. Intracellular coexpression of miR-S1 with miR-1266 abrogated the downregulation of TERT and decrease in telomerase activity induced by miR-1266. These effects of miR-S1 were also observed in miR-1266-expressing A549 cells infected with SV40. Moreover, the infected cells contained more Tag, replicated more viral DNA, and released more viral particles than control A549 cells infected with SV40, indicating that miR-S1-induced Tag downregulation was antagonized by miR-1266. Collectively, the present results revealed an interplay of viral and cellular miRNAs to sequester each other from their respective targets. This is a novel mechanism for viruses to manipulate the expression of viral and cellular proteins, contributing to not only viral lytic and latent replication but also cell transformation observed in viral infectious diseases including oncogenesis.
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15
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Che L, Du ZB, Wang WH, Wu JS, Han T, Chen YY, Han PY, Lei Z, Chen XX, He Y, Xu L, Lin X, Lin ZN, Lin YC. Intracellular antibody targeting HBx suppresses invasion and metastasis in hepatitis B virus-related hepatocarcinogenesis via protein phosphatase 2A-B56γ-mediated dephosphorylation of protein kinase B. Cell Prolif 2022; 55:e13304. [PMID: 35811356 PMCID: PMC9628248 DOI: 10.1111/cpr.13304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 06/15/2022] [Accepted: 06/22/2022] [Indexed: 12/24/2022] Open
Abstract
Objectives Hepatitis B virus X (HBx) is closely associated with HBV‐related hepatocarcinogenesis via the inactivation of tumour suppressors. Protein phosphatase 2A (PP2A) regulatory subunit B56 gamma (B56γ), as a tumour suppressor, plays a critical role in regulating cellular phosphorylation signals via dephosphorylation of signalling proteins. However, the underlying mechanism that B56γ involved in regulating HBx‐associated hepatocarcinogenesis phenotypes and mediating anti‐HBx antibody‐mediated tumour suppression remains unknown. Materials and Methods We used bioinformatics analysis, paired HCC patient specimens, HBx transgenic (HBx‐Tg) mice, xenograft nude mice, HBV stable replication in the HepG2.2.15 cells, and anti‐HBx antibody intervention to systematically evaluate the biological function of protein kinase B (AKT) dephosphorylation through B56γ in HBx‐associated hepatocarcinogenesis. Results Bioinformatics analysis revealed that AKT, matrix metalloproteinase 2 (MMP2), and MMP9 were markedly upregulated, while cell migration and viral carcinogenesis pathways were activated in HBV‐infected liver tissues and HBV‐associated HCC tissues. Our results demonstrated that HBx‐expression promotes AKT phosphorylation (p‐AKTThr308/Ser473), mediating the migration and invasion phenotypes in vivo and in vitro. Importantly, in clinical samples, HBx and B56γ were downregulated in HBV‐associated HCC tumour tissues compared with peritumor tissues. Moreover, intervention with site‐directed mutagenesis (AKTT308A, AKTS473A) of p‐AKTThr308/Ser473 mimics dephosphorylation, genetics‐based B56γ overexpression, and intracellular anti‐HBx antibody inhibited cell growth, migration, and invasion in HBx‐expressing HCC cells. Conclusions Our results demonstrated that B56γ inhibited HBV/HBx‐dependent hepatocarcinogenesis by regulating the dephosphorylation of p‐AKTThr308/Ser473 in HCC cells. The intracellular anti‐HBx antibody and the activator of B56γ may provide a multipattern chemopreventive strategy against HBV‐related HCC.
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Affiliation(s)
- Lin Che
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Ze-Bang Du
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Wei-Hua Wang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Jia-Shen Wu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Tun Han
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Yuan-Yuan Chen
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China.,China CDC Key Laboratory of Environment and Population Health, National Institute of Environmental Health, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Pei-Yu Han
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China.,Wuxi School of Medicine, Jiangnan University, Wuxi, China
| | - Zhao Lei
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Xiao-Xuan Chen
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Yun He
- Key Laboratory of Ministry of Education for Gastrointestinal Cancer, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Ling Xu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Xu Lin
- Key Laboratory of Ministry of Education for Gastrointestinal Cancer, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Zhong-Ning Lin
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Yu-Chun Lin
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
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16
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Shang D, Zhou T, Zhuang X, Wu Y, Liu H, Tu Z. Molecular dissection on inhibition of Ras-induced cellular senescence by small t antigen of SV40. Cell Mol Life Sci 2022; 79:242. [PMID: 35429286 PMCID: PMC11072472 DOI: 10.1007/s00018-022-04275-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 03/21/2022] [Accepted: 03/25/2022] [Indexed: 11/28/2022]
Abstract
Simian virus 40 (SV40) is a potentially oncogenic virus of monkey origin. Transmission, prevalence, and pathogenicity rates of SV40 are unclear, but infection can occur in humans, for example individuals with high contact with rhesus macaques and individuals that received contaminated early batches of polio vaccines in 1950-1963. In addition, several human polyomaviruses, proven carcinogenic, are also highly common in global populations. Cellular senescence is a major mechanism of cancer prevention in vivo. Hyperactivation of Ras usually induces cellular senescence rather than cell transformation. Previous studies suggest small t antigen (ST) of SV40 may interfere with cellular senescence induced by Ras. In the current study, ST was demonstrated to inhibit Ras-induced cellular senescence (RIS) and accumulation of DNA damage in Ras-activated cells. In addition, ST suppressed the signal transmission from BRaf to MEK and thus blocked the downstream transmission of the activated Ras signal. B56γ knockdown mimicked the inhibitory effects of ST overexpression on RIS. Furthermore, KSR1 knockdown inhibited Ras activation and the subsequent cellular senescence. Further mechanism studies indicated that the phosphorylation level of KSR1 rather than the levels of the total protein regulates the activation of Ras signaling pathway. In sum, ST inhibits the continuous hyperactivation of Ras signals by interfering with the normal functions of PP2A-B56γ of dephosphorylating KSR1, thus inhibiting the occurrence of cellular senescence. Although the roles of SV40 in human carcinogenesis are controversial so far, our study has shown that ST of polyomaviruses has tumorigenic potential by inhibiting oncogene-induced senescence (OIS) as a proof of concept.
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Affiliation(s)
- Dongsheng Shang
- School of Life Sciences, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Tianchu Zhou
- School of Life Sciences, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Xinying Zhuang
- School of Chinese Material Medica, Yunnan University of Chinese Medicine, Kunming, 650500, Yunnan, China
| | - Yanfang Wu
- School of Life Sciences, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Hanqing Liu
- School of Pharmacy, Jiangsu University, Zhenjiang, 212013, Jiangsu, China.
| | - Zhigang Tu
- School of Life Sciences, Jiangsu University, Zhenjiang, 212013, Jiangsu, China.
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17
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Goswami S, Mani R, Nunes J, Chiang CL, Zapolnik K, Hu E, Frissora F, Mo X, Walker LA, Yan P, Bundschuh R, Beaver L, Devine R, Tsai YT, Ventura A, Xie Z, Chen M, Lapalombella R, Walker A, Mims A, Larkin K, Grieselhuber N, Bennett C, Phelps M, Hertlein E, Behbehani G, Vasu S, Byrd JC, Muthusamy N. PP2A is a therapeutically targetable driver of cell fate decisions via a c-Myc/p21 axis in human and murine acute myeloid leukemia. Blood 2022; 139:1340-1358. [PMID: 34788382 PMCID: PMC8900275 DOI: 10.1182/blood.2020010344] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Accepted: 10/30/2021] [Indexed: 11/20/2022] Open
Abstract
Dysregulated cellular differentiation is a hallmark of acute leukemogenesis. Phosphatases are widely suppressed in cancers but have not been traditionally associated with differentiation. In this study, we found that the silencing of protein phosphatase 2A (PP2A) directly blocks differentiation in acute myeloid leukemia (AML). Gene expression and mass cytometric profiling revealed that PP2A activation modulates cell cycle and transcriptional regulators that program terminal myeloid differentiation. Using a novel pharmacological agent, OSU-2S, in parallel with genetic approaches, we discovered that PP2A enforced c-Myc and p21 dependent terminal differentiation, proliferation arrest, and apoptosis in AML. Finally, we demonstrated that PP2A activation decreased leukemia-initiating stem cells, increased leukemic blast maturation, and improved overall survival in murine Tet2-/-Flt3ITD/WT and human cell-line derived xenograft AML models in vivo. Our findings identify the PP2A/c-Myc/p21 axis as a critical regulator of the differentiation/proliferation switch in AML that can be therapeutically targeted in malignancies with dysregulated maturation fate.
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Affiliation(s)
- Swagata Goswami
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
- Molecular, Cellular, and Developmental Biology Graduate Program, The Ohio State University, Columbus, OH
| | | | - Jessica Nunes
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
- Molecular, Cellular, and Developmental Biology Graduate Program, The Ohio State University, Columbus, OH
| | - Chi-Ling Chiang
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
| | - Kevan Zapolnik
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
| | - Eileen Hu
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
| | - Frank Frissora
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
| | - Xiaokui Mo
- Center for Biostatistics, The Ohio State University, Columbus, OH
| | - Logan A Walker
- Biophysics Graduate Program, University of Michigan, Ann Arbor, MI
| | - Pearlly Yan
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
| | - Ralf Bundschuh
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH
- Department of Physics, The Ohio State University, Columbus, OH; and
| | - Larry Beaver
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
| | - Raymond Devine
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
| | - Yo-Ting Tsai
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
| | - Ann Ventura
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
| | - Zhiliang Xie
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
| | - Min Chen
- College of Pharmacy, The Ohio State University, Columbus, OH
| | - Rosa Lapalombella
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
| | - Alison Walker
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
| | - Alice Mims
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
| | - Karilyn Larkin
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
| | - Nicole Grieselhuber
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
| | - Chad Bennett
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
| | - Mitch Phelps
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
- College of Pharmacy, The Ohio State University, Columbus, OH
| | - Erin Hertlein
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
| | - Gregory Behbehani
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
| | - Sumithira Vasu
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
| | - John C Byrd
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
- College of Pharmacy, The Ohio State University, Columbus, OH
| | - Natarajan Muthusamy
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH
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18
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O’Connor CM, Taylor SE, Miller KM, Hurst L, Haanen TJ, Suhan TK, Zawacki KP, Noto FK, Trako J, Mohan A, Sangodkar J, Zamarin D, DiFeo A, Narla G. Targeting Ribonucleotide Reductase Induces Synthetic Lethality in PP2A-Deficient Uterine Serous Carcinoma. Cancer Res 2022; 82:721-733. [PMID: 34921012 PMCID: PMC8857033 DOI: 10.1158/0008-5472.can-21-1987] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 10/14/2021] [Accepted: 11/30/2021] [Indexed: 11/16/2022]
Abstract
Uterine serous carcinoma (USC) is a highly aggressive endometrial cancer subtype with limited therapeutic options and a lack of targeted therapies. While mutations to PPP2R1A, which encodes the predominant protein phosphatase 2A (PP2A) scaffolding protein Aα, occur in 30% to 40% of USC cases, the clinical actionability of these mutations has not been studied. Using a high-throughput screening approach, we showed that mutations in Aα results in synthetic lethality following treatment with inhibitors of ribonucleotide reductase (RNR). In vivo, multiple models of Aα mutant uterine serous tumors were sensitive to clofarabine, an RNR inhibitor (RNRi). Aα-mutant cells displayed impaired checkpoint signaling upon RNRi treatment and subsequently accumulated more DNA damage than wild-type (WT) cells. Consistently, inhibition of PP2A activity using LB-100, a catalytic inhibitor, sensitized WT USC cells to RNRi. Analysis of The Cancer Genome Atlas data indicated that inactivation of PP2A, through loss of PP2A subunit expression, was prevalent in USC, with 88% of patients with USC harboring loss of at least one PP2A gene. In contrast, loss of PP2A subunit expression was rare in uterine endometrioid carcinomas. While RNRi are not routinely used for uterine cancers, a retrospective analysis of patients treated with gemcitabine as a second- or later-line therapy revealed a trend for improved outcomes in patients with USC treated with RNRi gemcitabine compared with patients with endometrioid histology. Overall, our data provide experimental evidence to support the use of ribonucleotide reductase inhibitors for the treatment of USC. SIGNIFICANCE A drug repurposing screen identifies synthetic lethal interactions in PP2A-deficient uterine serous carcinoma, providing potential therapeutic avenues for treating this deadly endometrial cancer.
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Affiliation(s)
- Caitlin M. O’Connor
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
- Rogel Cancer Center, The University of Michigan, Ann Arbor, Michigan
| | - Sarah E. Taylor
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio
| | - Kathryn M. Miller
- Department of Surgery, Memorial Sloan Kettering Cancer Center, New York City, New York
| | - Lauren Hurst
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
| | - Terrance J. Haanen
- Rogel Cancer Center, The University of Michigan, Ann Arbor, Michigan
- Department of Cancer Biology, The University of Michigan, Ann Arbor, Michigan
| | - Tahra K. Suhan
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
| | - Kaitlin P. Zawacki
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
| | | | - Jonida Trako
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
| | - Arathi Mohan
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
| | - Jaya Sangodkar
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
| | - Dmitriy Zamarin
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York City, New York
| | - Analisa DiFeo
- Rogel Cancer Center, The University of Michigan, Ann Arbor, Michigan
- Department of Pathology, The University of Michigan, Ann Arbor, Michigan
- Department of Obstetrics and Gynecology, The University of Michigan, Ann Arbor, Michigan
| | - Goutham Narla
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
- Rogel Cancer Center, The University of Michigan, Ann Arbor, Michigan
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19
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Chen S, Chen L, Ye L, Jiang Y, Li Q, Zhang H, Zhang R, Li H, Yu D, Zhang R, Niu Y, Zhao Q, Liu J, Ouyang G, Aschner M, Zheng Y, Zhang L, Chen W, Li D. PP2A-mTOR-p70S6K/4E-BP1 axis regulates M1 polarization of pulmonary macrophages and promotes ambient particulate matter induced mouse lung injury. JOURNAL OF HAZARDOUS MATERIALS 2022; 424:127624. [PMID: 34740159 DOI: 10.1016/j.jhazmat.2021.127624] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 10/10/2021] [Accepted: 10/25/2021] [Indexed: 06/13/2023]
Abstract
To identify key signaling pathways involved in ambient particulate matter (PM)-induced pulmonary injury, we generated a mouse model with myeloid-specific deletion of Ppp2r1a gene (encoding protein phosphatase 2 A (PP2A) A subunit), and conducted experiments in a real-ambient PM exposure system. PP2A Aα-/- homozygote (Aα HO) mice and matched wild-type (WT) littermates were exposed to PM over 3-week and 6-week. The effects of PM exposure on pulmonary inflammation, oxidative stress, and apoptosis were significantly enhanced in Aα HO compared to WT mice. The number of pulmonary macrophages increased by 74.8~88.0% and enhanced M1 polarization appeared in Aα HO mice upon PM exposure. Secretion of M1 macrophage-related inflammatory cytokines was significantly increased in Aα HO vs. WT mice following PM exposure. Moreover, we demonstrated that PP2A-B56α holoenzyme regulated M1 polarization and that the mTOR signaling pathway mediated the persistent M1 polarization upon PM2.5 exposure. Importantly, PP2A-B56α holoenzyme was shown to complex with mTOR/p70S6K/4E-BP1, and suppression of B56α led to enhanced phosphorylation of mTOR, p70S6K, and 4E-BP1. These observations demonstrate that the PP2A-mTOR-p70S6K/4E-BP1 signaling is a critical pathway in mediating macrophage M1 polarization, which contributes to PM-induced pulmonary injury.
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Affiliation(s)
- Shen Chen
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Liping Chen
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Lizhu Ye
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Yue Jiang
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Qiong Li
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Haiyan Zhang
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Rui Zhang
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Huiyao Li
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Dianke Yu
- Department of Toxicology, School of Public Health, Qingdao University, Qingdao 266021, China
| | - Rong Zhang
- Department of Toxicology, School of Public Health, Hebei Medical University, Shijiazhuang 050017, China
| | - Yujie Niu
- Department of Toxicology, School of Public Health, Hebei Medical University, Shijiazhuang 050017, China
| | - Qun Zhao
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Science, National Chromatographic Research and Analysis Center, Dalian 116023, China
| | - Jianhui Liu
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Science, National Chromatographic Research and Analysis Center, Dalian 116023, China
| | - Gangfeng Ouyang
- KLGHEI of Environment and Energy Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, Guangdong, China
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Forchheimer 209, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Yuxin Zheng
- Department of Toxicology, School of Public Health, Qingdao University, Qingdao 266021, China
| | - Lihua Zhang
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Science, National Chromatographic Research and Analysis Center, Dalian 116023, China
| | - Wen Chen
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China.
| | - Daochuan Li
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China.
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20
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Ke W, Zhou Y, Lai Y, Long S, Fang L, Xiao S. Porcine reproductive and respiratory syndrome virus nsp4 positively regulates cellular cholesterol to inhibit type I interferon production. Redox Biol 2021; 49:102207. [PMID: 34911669 PMCID: PMC8758914 DOI: 10.1016/j.redox.2021.102207] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 11/26/2021] [Accepted: 12/07/2021] [Indexed: 02/07/2023] Open
Abstract
Cellular cholesterol plays an important role in the life cycles of enveloped viruses. Previous studies by our group and other groups have demonstrated that the depletion of cellular cholesterol by methyl-β-cyclodextrin (MβCD) reduces the proliferation of porcine reproductive and respiratory syndrome virus (PRRSV), a porcine Arterivirus that has been devastating the swine industry worldwide for over two decades. However, how PRRSV infection regulates cholesterol synthesis is not fully understood. In this study, we showed that PRRSV infection upregulated the activity of protein phosphatase 2 (PP2A), which subsequently activated 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR), the rate-limiting enzyme in the cholesterol synthesis pathway, to increase the levels of cellular cholesterol. By screening the PRRSV-encoded proteins, we showed that nsp4 dominated the upregulation of cellular cholesterol, independently of the 3C-like protease activity of nsp4. A mutation analysis showed that domain I (amino acids 1–80) of PRRSV nsp4 interacted with PR65 alpha (PR65α), the structural subunit, and PP2Ac, the catalytic subunit, of PP2A. Importantly, domain I of nsp4 inhibited Sendai virus-induced interferon β production, and this inhibitory effect was eliminated by Lovastatin, an HMGCR inhibitor, indicating that the upregulation of cellular cholesterol by nsp4 is a strategy used by PRRSV to suppress the antiviral innate immunity of its host. Collectively, we here demonstrated the mechanism by which PRRSV regulates cellular cholesterol synthesis and reported a novel strategy by which PRRSV evades its host's antiviral innate immune response. PRRSV nsp4 up-regulates cellular cholesterol via the PP2A-HMGCR pathway. Nsp4 domain I (amino acids 1–80) interacts with A and C subunits of PP2A. Nsp4 domain I inhibits IFN-I production by upregulating cellular cholesterol. The HMGCR inhibitor Lovastatin inhibits PRRSV proliferation.
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Affiliation(s)
- Wenting Ke
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China; The Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, China
| | - Yanrong Zhou
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China; The Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, China
| | - Yinan Lai
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China; The Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, China
| | - Siwen Long
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China; The Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, China
| | - Liurong Fang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China; The Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, China.
| | - Shaobo Xiao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China; The Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, China.
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21
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Brauer BL, Wiredu K, Mitchell S, Moorhead GB, Gerber SA, Kettenbach AN. Affinity-based profiling of endogenous phosphoprotein phosphatases by mass spectrometry. Nat Protoc 2021; 16:4919-4943. [PMID: 34518704 PMCID: PMC8822503 DOI: 10.1038/s41596-021-00604-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 07/12/2021] [Indexed: 02/08/2023]
Abstract
Phosphoprotein phosphatases (PPPs) execute >90% of serine/threonine dephosphorylation in cells and tissues. While the role of PPPs in cell biology and diseases such as cancer, cardiac hypertrophy and Alzheimer's disease is well established, the molecular mechanisms governing and governed by PPPs still await discovery. Here we describe a chemical proteomic strategy, phosphatase inhibitor beads and mass spectrometry (PIB-MS), that enables the identification and quantification of PPPs and their posttranslational modifications in as little as 12 h. Using a specific but nonselective PPP inhibitor immobilized on beads, PIB-MS enables the efficient affinity-capture, identification and quantification of endogenous PPPs and associated proteins ('PPPome') from cells and tissues. PIB-MS captures functional, endogenous PPP subunit interactions and enables discovery of new binding partners. It performs PPP enrichment without exogenous expression of tagged proteins or specific antibodies. Because PPPs are among the most conserved proteins across evolution, PIB-MS can be employed in any cell line, tissue or organism.
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Affiliation(s)
- Brooke L Brauer
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Kwame Wiredu
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Sierra Mitchell
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Greg B Moorhead
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Scott A Gerber
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
- Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, NH, USA
| | - Arminja N Kettenbach
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA.
- Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, NH, USA.
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22
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Barski MS, Minnell JJ, Maertens GN. PP2A Phosphatase as an Emerging Viral Host Factor. Front Cell Infect Microbiol 2021; 11:725615. [PMID: 34422684 PMCID: PMC8371333 DOI: 10.3389/fcimb.2021.725615] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 07/20/2021] [Indexed: 12/12/2022] Open
Abstract
Protein phosphatase 2A (PP2A) is one of the most ubiquitous cellular proteins and is responsible for the vast majority of Ser/Thr phosphatase activity in eukaryotes. PP2A is a heterotrimer, and its assembly, intracellular localization, enzymatic activity, and substrate specificity are subject to dynamic regulation. Each of its subunits can be targeted by viral proteins to hijack and modulate its activity and downstream signaling to the advantage of the virus. Binding to PP2A is known to be essential to the life cycle of many viruses and seems to play a particularly crucial role for oncogenic viruses, which utilize PP2A to transform infected cells through controlling the cell cycle and apoptosis. Here we summarise the latest developments in the field of PP2A viral targeting; in particular recent discoveries of PP2A hijacking through molecular mimicry of a B56-specific motif by several different viruses. We also discuss the potential as well as shortcomings for therapeutic intervention in the face of our current understanding of viral PP2A targeting.
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Affiliation(s)
| | | | - Goedele Noella Maertens
- Department of Infectious Disease, Section of Molecular Virology, St Mary’s Hospital, Imperial College London, London, United Kingdom
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23
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Cancer stem cell phosphatases. Biochem J 2021; 478:2899-2920. [PMID: 34319405 DOI: 10.1042/bcj20210254] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 07/05/2021] [Accepted: 07/07/2021] [Indexed: 12/15/2022]
Abstract
Cancer stem cells (CSCs) are involved in the initiation and progression of human malignancies by enabling cancer tissue self-renewal capacity and constituting the therapy-resistant population of tumor cells. However, despite the exhausting characterization of CSC genetics, epigenetics, and kinase signaling, eradication of CSCs remains an unattainable goal in most human malignancies. While phosphatases contribute equally with kinases to cellular phosphoregulation, our understanding of phosphatases in CSCs lags severely behind our knowledge about other CSC signaling mechanisms. Many cancer-relevant phosphatases have recently become druggable, indicating that further understanding of the CSC phosphatases might provide novel therapeutic opportunities. This review summarizes the current knowledge about fundamental, but yet poorly understood involvement of phosphatases in the regulation of major CSC signaling pathways. We also review the functional roles of phosphatases in CSC self-renewal, cancer progression, and therapy resistance; focusing particularly on hematological cancers and glioblastoma. We further discuss the small molecule targeting of CSC phosphatases and their therapeutic potential in cancer combination therapies.
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24
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Sandal P, Jong CJ, Merrill RA, Song J, Strack S. Protein phosphatase 2A - structure, function and role in neurodevelopmental disorders. J Cell Sci 2021; 134:270819. [PMID: 34228795 DOI: 10.1242/jcs.248187] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Neurodevelopmental disorders (NDDs), including intellectual disability (ID), autism and schizophrenia, have high socioeconomic impact, yet poorly understood etiologies. A recent surge of large-scale genome or exome sequencing studies has identified a multitude of mostly de novo mutations in subunits of the protein phosphatase 2A (PP2A) holoenzyme that are strongly associated with NDDs. PP2A is responsible for at least 50% of total Ser/Thr dephosphorylation in most cell types and is predominantly found as trimeric holoenzymes composed of catalytic (C), scaffolding (A) and variable regulatory (B) subunits. PP2A can exist in nearly 100 different subunit combinations in mammalian cells, dictating distinct localizations, substrates and regulatory mechanisms. PP2A is well established as a regulator of cell division, growth, and differentiation, and the roles of PP2A in cancer and various neurodegenerative disorders, such as Alzheimer's disease, have been reviewed in detail. This Review summarizes and discusses recent reports on NDDs associated with mutations of PP2A subunits and PP2A-associated proteins. We also discuss the potential impact of these mutations on the structure and function of the PP2A holoenzymes and the etiology of NDDs.
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Affiliation(s)
- Priyanka Sandal
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Chian Ju Jong
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Ronald A Merrill
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Jianing Song
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Stefan Strack
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
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25
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Meeusen B, Cortesi EE, Domènech Omella J, Sablina A, Ventura JJ, Janssens V. PPP2R4 dysfunction promotes KRAS-mutant lung adenocarcinoma development and mediates opposite responses to MEK and mTOR inhibition. Cancer Lett 2021; 520:57-67. [PMID: 34216687 DOI: 10.1016/j.canlet.2021.06.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 06/21/2021] [Accepted: 06/24/2021] [Indexed: 12/30/2022]
Abstract
KRAS-mutant lung adenocarcinomas represent the largest molecular subgroup of non-small cell lung cancers (NSCLC) and are notorious for their dismal survival perspectives. To gain more insights in etiology and therapeutic response, we focused on the tumor suppressor Protein Phosphatase 2A (PP2A) as a player in KRAS oncogenic signaling. We report that the PP2A activator PTPA (encoded by PPP2R4) is commonly affected in NSCLC by heterozygous loss and low-frequent loss-of-function mutation, and this is specifically associated with poorer overall survival of KRAS-mutant lung adenocarcinoma patients. Reduced or mutant PPP2R4 expression in A549 cells increased anchorage-independent growth in vitro and xenograft growth in vivo, correlating with increased Ki67 and c-MYC expression. Moreover, KrasG12D-induced lung tumorigenesis was significantly accelerated in Ppp2r4 gene trapped mice as compared to Ppp2r4 wild-type. A confined kinase inhibitor screen revealed that PPP2R4-depletion induced resistance against selumetinib (MEK inhibitor), but unexpectedly sensitized cells for temsirolimus (mTOR inhibitor), in vitro and in vivo. Our findings underscore a clinically relevant role for PTPA loss-of-function in KRAS-mutant NSCLC etiology and kinase inhibitor response.
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Affiliation(s)
- Bob Meeusen
- Laboratory of Protein Phosphorylation & Proteomics, Dept. Cellular & Molecular Medicine, KU Leuven, B-3000, Leuven, Belgium; KU Leuven Cancer Institute (LKI), B-3000, Leuven, Belgium
| | - Emanuela Elsa Cortesi
- Translational Cell & Tissue Research, Dept. Imaging & Pathology, KU Leuven, B-3000, Leuven, Belgium
| | - Judit Domènech Omella
- Laboratory of Protein Phosphorylation & Proteomics, Dept. Cellular & Molecular Medicine, KU Leuven, B-3000, Leuven, Belgium; KU Leuven Cancer Institute (LKI), B-3000, Leuven, Belgium
| | - Anna Sablina
- KU Leuven Cancer Institute (LKI), B-3000, Leuven, Belgium; Laboratory for Mechanisms of Cell Transformation, VIB Center for Cancer Biology & Dept. Oncology, KU Leuven, B-3000, Leuven, Belgium
| | - Juan-Jose Ventura
- Translational Cell & Tissue Research, Dept. Imaging & Pathology, KU Leuven, B-3000, Leuven, Belgium
| | - Veerle Janssens
- Laboratory of Protein Phosphorylation & Proteomics, Dept. Cellular & Molecular Medicine, KU Leuven, B-3000, Leuven, Belgium; KU Leuven Cancer Institute (LKI), B-3000, Leuven, Belgium.
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26
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Abstract
Background: Several mechanisms likely cooperate with the mitogen-activated protein (MAP)-kinase pathway to promote cancer progression in the thyroid. One putative pathway is NOTCH signaling, which is implicated in several other malignancies. In thyroid cancer, data regarding the role of the NOTCH pathway are insufficient and even contradictory. Methods: A BRAFV600E-driven papillary thyroid carcinoma (PTC) mouse model was subjected to NOTCH pathway genetic alterations, and the tumor burden was followed by ultrasound. Further analyses were performed on PTC cell lines or noncancerous cells transfected with NOTCHIC or BRAFV600E, which were then subjected to pharmacological treatment with MAP-kinase or NOTCH pathway inhibitors. Results: The presence of the BRAFV600E mutation coupled with overexpression of the NOTCH intracellular domain led to significantly bigger thyroid tumors in mice, to a more aggressive carcinoma, and decreased overall survival. Although more cystic, the tumors did not progress into anaplastic thyroid carcinomas. On the contrary, the deletion of RBP-jκ (a major cofactor involved in NOTCH signaling) did not alter the phenotype in mice. BRAFV600E-mutated PTC cell lines were resistant to pharmacological inhibition of the NOTCH pathway. Inhibition of MEK1/2 uncovered a predominant effect on Hes1/Hey1 transcription compared with NOTCH inhibition in BRAFV600E-mutated cell lines. Finally, γ-secretase activity and γ-secretase subunit transcription levels were dependent on ERK activation. Our findings suggest that MAP-kinase activity overrides the NOTCH pathway in the context of thyroid cancer. Conclusions: The interaction between the BRAF and NOTCH pathways demonstrates that the BRAFV600E mutation might bypass NOTCH and exert a strong positive effect on NOTCH downstream targets in thyroid carcinoma.
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Affiliation(s)
- Florian Traversi
- Institute of Biochemistry and Molecular Medicine, and Swiss National Center of Competence in Research (NCCR) TransCure, University of Bern, Bern, Switzerland
| | - Amandine Stooss
- Institute of Biochemistry and Molecular Medicine, and Swiss National Center of Competence in Research (NCCR) TransCure, University of Bern, Bern, Switzerland
| | | | - Roch-Philippe Charles
- Institute of Biochemistry and Molecular Medicine, and Swiss National Center of Competence in Research (NCCR) TransCure, University of Bern, Bern, Switzerland
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27
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Abstract
Chromosome instability (CIN) is a major hallmark of cancer cells and believed to drive tumor progression. Several cellular defects including weak centromeric cohesion are proposed to promote CIN, but the molecular mechanisms underlying these defects are poorly understood. In a screening for SET protein levels in various cancer cell lines, we found that most of the cancer cells exhibit higher SET protein levels than nontransformed cells, including RPE-1. Cancer cells with elevated SET often show weak centromeric cohesion, revealed by MG132-induced cohesion fatigue. Partial SET knockdown largely strengthens centromeric cohesion in cancer cells without increasing overall phosphatase 2A (PP2A) activity. Pharmacologically increased PP2A activity in these cancer cells barely ameliorates centromeric cohesion. These results suggest that compromised PP2A activity, a common phenomenon in cancer cells, may not be responsible for weak centromeric cohesion. Furthermore, centromeric cohesion in cancer cells can be strengthened by ectopic Sgo1 overexpression and weakened by SET WT, not by Sgo1-binding-deficient mutants. Altogether, these findings demonstrate that SET overexpression contributes to impaired centromeric cohesion in cancer cells and illustrate misregulated SET-Sgo1 pathway as an underlying mechanism.
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Affiliation(s)
- Lu Yang
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112
| | - Qian Zhang
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112
| | - Tianhua Niu
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112
| | - Hong Liu
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112.,Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112.,Tulane Aging Center, Tulane University School of Medicine, New Orleans, LA 70112
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28
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Chen L, Guo P, Li W, Fang F, Zhu W, Fan J, Wang F, Gao Y, Zhao Q, Wang Q, Xiao Y, Xing X, Li D, Shi T, Yu D, Aschner M, Zhang L, Chen W. Perturbation of Specific Signaling Pathways Is Involved in Initiation of Mouse Liver Fibrosis. Hepatology 2021; 73:1551-1569. [PMID: 32654205 DOI: 10.1002/hep.31457] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/09/2020] [Accepted: 06/11/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND AND AIMS To identify the regulatory role of protein phosphatase 2A (PP2A) in the development of liver disease, we generated a mouse model with hepatocyte-specific deletion of Ppp2r1a gene (encoding PP2A Aα subunit). APPROACH AND RESULTS Homozygote (HO) mice and matched wild-type littermates were investigated at 3, 6, 9, 12, 15, and 18 months of age. Pathological examination showed that PP2A Aα deficiency in hepatocytes resulted in progressive liver fibrosis phenotype from 9 months of age. No hepatocyte death was observed in HO mice. However, perturbation of pathways including epidermal growth factor receptor 1 (EGFR1), amino acid metabolism, and translation factors as well as leptin and adiponectin led to pronounced hepatic fibrosis. In vitro studies demonstrated the involvement of specific B subunit complexes in the regulation of EGFR1 signaling pathway and cross talk between defected hepatocytes and stimulation of interstitial hyperplasia. It is noteworthy that HO mice failed to develop hepatocellular carcinoma for as long as 22 months of age. We further demonstrate that PP2A Aβ-containing holoenzymes played a critical role in preventing hepatocyte apoptosis and antagonizing tumorigenesis through specific pathways on Aα loss. Furthermore, PP2A Aα and Aβ were functionally distinct, and the Aβ isoform failed to substitute for Aα in the development of inflammation and liver fibrosis. CONCLUSIONS These observations identify pathways that contribute to the pathogenesis of liver fibrosis and provide putative therapeutic targets for its treatment.
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Affiliation(s)
- Liping Chen
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Ping Guo
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Wenxue Li
- Department of Toxicology, Guangzhou Center for Disease Control and Prevention, Guangzhou, China
| | - Fei Fang
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Science, National Chromatographic Research and Analysis Center, Dalian, China
| | - Wei Zhu
- Department of Toxicology, Guangzhou Center for Disease Control and Prevention, Guangzhou, China
| | - Junling Fan
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Fangping Wang
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Yuanyuan Gao
- The Center for Bioinformatics and Computational Biology, Shanghai Key Laboratory of Regulatory Biology, The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Qun Zhao
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Science, National Chromatographic Research and Analysis Center, Dalian, China
| | - Qing Wang
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Yongmei Xiao
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Xiumei Xing
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Daochuan Li
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Tieliu Shi
- The Center for Bioinformatics and Computational Biology, Shanghai Key Laboratory of Regulatory Biology, The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Dianke Yu
- School of Public Health, Qingdao University, Qingdao, China
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY
| | - Lihua Zhang
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Science, National Chromatographic Research and Analysis Center, Dalian, China
| | - Wen Chen
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
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29
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Thapa C, Roivas P, Haataja T, Permi P, Pentikäinen U. The Interaction Mechanism of Intrinsically Disordered PP2A Inhibitor Proteins ARPP-16 and ARPP-19 With PP2A. Front Mol Biosci 2021; 8:650881. [PMID: 33842550 PMCID: PMC8032985 DOI: 10.3389/fmolb.2021.650881] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 03/03/2021] [Indexed: 12/01/2022] Open
Abstract
Protein phosphatase 2A (PP2A) activity is critical for maintaining normal physiological cellular functions. PP2A is inhibited by endogenous inhibitor proteins in several pathological conditions including cancer. A PP2A inhibitor protein, ARPP-19, has recently been connected to several human cancer types. Accordingly, the knowledge about ARPP-19—PP2A inhibition mechanism is crucial for the understanding the disease development and the therapeutic targeting of ARPP-19—PP2A. Here, we show the first structural characterization of ARPP-19, and its splice variant ARPP-16 using NMR spectroscopy, and SAXS. The results reveal that both ARPP proteins are intrinsically disordered but contain transient secondary structure elements. The interaction mechanism of ARPP-16/19 with PP2A was investigated using microscale thermophoresis and NMR spectroscopy. Our results suggest that ARPP—PP2A A-subunit interaction is mediated by linear motif and has modest affinity whereas, the interaction of ARPPs with B56-subunit is weak and transient. Like many IDPs, ARPPs are promiscuous binders that transiently interact with PP2A A- and B56 subunits using multiple interaction motifs. In summary, our results provide a good starting point for future studies and development of therapeutics that block ARPP-PP2A interactions.
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Affiliation(s)
- Chandan Thapa
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyvaskyla, Jyvaskyla, Finland.,Institute of Biomedicine, University of Turku, Turku, Finland.,Turku BioScience Centre, University of Turku, Turku, Finland
| | - Pekka Roivas
- Institute of Biomedicine, University of Turku, Turku, Finland.,Turku BioScience Centre, University of Turku, Turku, Finland
| | - Tatu Haataja
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyvaskyla, Jyvaskyla, Finland.,Institute of Biomedicine, University of Turku, Turku, Finland.,Turku BioScience Centre, University of Turku, Turku, Finland
| | - Perttu Permi
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyvaskyla, Jyvaskyla, Finland.,Department of Chemistry and Nanoscience Center, University of Jyvaskyla, Jyvaskyla, Finland
| | - Ulla Pentikäinen
- Institute of Biomedicine, University of Turku, Turku, Finland.,Turku BioScience Centre, University of Turku, Turku, Finland
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30
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Mei J, Tian H, Huang HS, Hsu CF, Liou Y, Wu N, Zhang W, Chu TY. Cellular models of development of ovarian high-grade serous carcinoma: A review of cell of origin and mechanisms of carcinogenesis. Cell Prolif 2021; 54:e13029. [PMID: 33768671 PMCID: PMC8088460 DOI: 10.1111/cpr.13029] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 02/19/2021] [Accepted: 03/03/2021] [Indexed: 12/11/2022] Open
Abstract
High-grade serous carcinoma (HGSC) is the most common and malignant histological type of epithelial ovarian cancer, the origin of which remains controversial. Currently, the secretory epithelial cells of the fallopian tube are regarded as the main origin and the ovarian surface epithelial cells as a minor origin. In tubal epithelium, these cells acquire TP53 mutations and expand to a morphologically normal 'p53 signature' lesion, transform to serous tubal intraepithelial carcinoma and metastasize to the ovaries and peritoneum where they develop into HGSC. This shifting paradigm of the main cell of origin has revolutionarily changed the focus of HGSC research. Various cell lines have been derived from the two cellular origins by acquiring immortalization via overexpression of hTERT plus disruption of TP53 and the CDK4/RB pathway. Malignant transformation was achieved by adding canonical driver mutations (such as gain of CCNE1) revealed by The Cancer Genome Atlas or by noncanonical gain of YAP and miR181a. Alternatively, because of the extreme chromosomal instability, spontaneous transformation can be achieved by long passage of murine immortalized cells, whereas in humans, it requires ovulatory follicular fluid, containing regenerating growth factors to facilitate spontaneous transformation. These artificially and spontaneously transformed cell systems in both humans and mice have been widely used to discover carcinogens, oncogenic pathways and malignant behaviours in the development of HGSC. Here, we review the origin, aetiology and carcinogenic mechanism of HGSC and comprehensively summarize the cell models used to study this fatal cancer having multiple cells of origin and overt genomic instability.
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Affiliation(s)
- Jie Mei
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha, China.,Engineering Research Center of Applied Technology of Pharmacogenomics, Ministry of Education, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Changsha, China
| | - Huixiang Tian
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, China
| | - Hsuan-Shun Huang
- Center for Prevention and Therapy of Gynecological Cancers, Department of Research, Buddhist Tzu Chi General Hospital, Hualien, Taiwan, ROC
| | - Che-Fang Hsu
- Center for Prevention and Therapy of Gynecological Cancers, Department of Research, Buddhist Tzu Chi General Hospital, Hualien, Taiwan, ROC
| | - Yuligh Liou
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha, China
| | - Nayiyuan Wu
- Hunan Cancer Hospital, The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Hunan, China
| | - Wei Zhang
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha, China.,Engineering Research Center of Applied Technology of Pharmacogenomics, Ministry of Education, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Changsha, China
| | - Tang-Yuan Chu
- Center for Prevention and Therapy of Gynecological Cancers, Department of Research, Buddhist Tzu Chi General Hospital, Hualien, Taiwan, ROC.,Department of Obstetrics & Gynecology, Buddhist Tzu Chi General Hospital, Hualien, Taiwan, ROC.,Department of Life Sciences, Tzu Chi University, Hualien, Taiwan, ROC
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31
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DeCaprio JA. Molecular Pathogenesis of Merkel Cell Carcinoma. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2020; 16:69-91. [PMID: 33228463 DOI: 10.1146/annurev-pathmechdis-012419-032817] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Merkel cell carcinoma (MCC) is an aggressive neuroendocrine carcinoma of the skin with two distinct etiologies. Clonal integration of Merkel cell polyomavirus DNA into the tumor genome with persistent expression of viral T antigens causes at least 60% of all MCC. UV damage leading to highly mutated genomes causes a nonviral form of MCC. Despite these distinct etiologies, both forms of MCC are similar in presentation, prognosis, and response to therapy. At least three oncogenic transcriptional programs feature prominently in both forms of MCC driven by the virus or by mutation. Both forms of MCC have a high proliferative growth rate with increased levels of cell cycle-dependent genes due to inactivation of the tumor suppressors RB and p53, a strong MYC signature due to MYCL activation by the virus or gene amplification, and an attenuated neuroendocrine differentiation program driven by the ATOH1 transcription factor.
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Affiliation(s)
- James A DeCaprio
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA; .,Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.,Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115, USA
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32
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Bao Y, Oguz G, Lee WC, Lee PL, Ghosh K, Li J, Wang P, Lobie PE, Ehmsen S, Ditzel HJ, Wong A, Tan EY, Lee SC, Yu Q. EZH2-mediated PP2A inactivation confers resistance to HER2-targeted breast cancer therapy. Nat Commun 2020; 11:5878. [PMID: 33208750 PMCID: PMC7674491 DOI: 10.1038/s41467-020-19704-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 10/23/2020] [Indexed: 12/13/2022] Open
Abstract
HER2-targeted therapy has yielded a significant clinical benefit in patients with HER2+ breast cancer, yet disease relapse due to intrinsic or acquired resistance remains a significant challenge in the clinic. Here, we show that the protein phosphatase 2A (PP2A) regulatory subunit PPP2R2B is a crucial determinant of anti-HER2 response. PPP2R2B is downregulated in a substantial subset of HER2+ breast cancers, which correlates with poor clinical outcome and resistance to HER2-targeted therapies. EZH2-mediated histone modification accounts for the PPP2R2B downregulation, resulting in sustained phosphorylation of PP2A targets p70S6K and 4EBP1 which leads to resistance to inhibition by anti-HER2 treatments. Genetic depletion or inhibition of EZH2 by a clinically-available EZH2 inhibitor restores PPP2R2B expression, abolishes the residual phosphorylation of p70S6K and 4EBP1, and resensitizes HER2+ breast cancer cells to anti-HER2 treatments both in vitro and in vivo. Furthermore, the same epigenetic mechanism also contributes to the development of acquired resistance through clonal selection. These findings identify EZH2-dependent PPP2R2B suppression as an epigenetic control of anti-HER2 resistance, potentially providing an opportunity to mitigate anti-HER2 resistance with EZH2 inhibitors.
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Affiliation(s)
- Yi Bao
- Cancer Science Institute of Singapore, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore.,Cancer Precision Medicine, Genome Institute of Singapore, Agency for Science, Technology, and Research, Biopolis, Singapore, 138672, Singapore
| | - Gokce Oguz
- Cancer Precision Medicine, Genome Institute of Singapore, Agency for Science, Technology, and Research, Biopolis, Singapore, 138672, Singapore
| | - Wee Chyan Lee
- Cancer Precision Medicine, Genome Institute of Singapore, Agency for Science, Technology, and Research, Biopolis, Singapore, 138672, Singapore
| | - Puay Leng Lee
- Cancer Precision Medicine, Genome Institute of Singapore, Agency for Science, Technology, and Research, Biopolis, Singapore, 138672, Singapore
| | - Kakaly Ghosh
- Cancer Precision Medicine, Genome Institute of Singapore, Agency for Science, Technology, and Research, Biopolis, Singapore, 138672, Singapore
| | - Jiayao Li
- Cancer Research Institute, Jinan University, Guangzhou, China
| | - Panpan Wang
- Cancer Research Institute, Jinan University, Guangzhou, China
| | - Peter E Lobie
- Cancer Science Institute of Singapore, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore.,Tsinghua-Berkeley Shenzhen Institute, Guangdong Province and Shenzhen Bay Laboratory, Tsinghua University, Shenzhen, Guangdong Province, China
| | - Sidse Ehmsen
- Department of Oncology, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark, 5230, Odense, Denmark
| | - Henrik J Ditzel
- Department of Oncology, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark, 5230, Odense, Denmark.,Department of Cancer and Inflammation Research, Institute of Molecular Medicine, University of Southern Denmark, 5230, Odense, Denmark
| | - Andrea Wong
- Department of Haematology-Oncology, National University Cancer Institute, National University Health System, Singapore, 119047, Singapore
| | - Ern Yu Tan
- Department of General Surgery, Tan Tock Seng Hospital, Singapore, Singapore
| | - Soo Chin Lee
- Cancer Science Institute of Singapore, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore. .,Department of Haematology-Oncology, National University Cancer Institute, National University Health System, Singapore, 119047, Singapore.
| | - Qiang Yu
- Cancer Precision Medicine, Genome Institute of Singapore, Agency for Science, Technology, and Research, Biopolis, Singapore, 138672, Singapore. .,Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore. .,Cancer and Stem Cell Biology, DUKE-NUS Graduate Medical School of Singapore, Singapore, 169857, Singapore.
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33
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Abstract
Members of the PP2A family of serine/threonine phosphatases are important human tumor suppressor genes. Unlike most tumor suppressors, they are rarely mutated/deleted, but rather are impaired by "inhibitor proteins." Two papers in this issue of Cell show how some phenothiazine derivatives reactivate specific PP2A isozymes with potential benefit in cancer and other diseases.
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Affiliation(s)
- Jukka Westermarck
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, 20520 Turku, Finland; Institute of Biomedicine, University of Turku, 20520 Turku, Finland
| | - Benjamin G Neel
- Perlmutter Cancer Center, NYU School of Medicine, NY Langone Health, New York, NY 10016, USA.
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34
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Nasa I, Kettenbach AN. Effects of carboxyl-terminal methylation on holoenzyme function of the PP2A subfamily. Biochem Soc Trans 2020; 48:2015-2027. [PMID: 33125487 PMCID: PMC8380034 DOI: 10.1042/bst20200177] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 09/14/2020] [Accepted: 09/16/2020] [Indexed: 01/07/2023]
Abstract
Phosphoprotein Phosphatases (PPPs) are enzymes highly conserved from yeast and human and catalyze the majority of the serine and threonine dephosphorylation in cells. To achieve substrate specificity and selectivity, PPPs form multimeric holoenzymes consisting of catalytic, structural/scaffolding, and regulatory subunits. For the Protein Phosphatase 2A (PP2A)-subfamily of PPPs, holoenzyme assembly is at least in part regulated by an unusual carboxyl-terminal methyl-esterification, commonly referred to as 'methylation'. Carboxyl-terminal methylation is catalyzed by Leucine carboxyl methyltransferase-1 (LCMT1) that utilizes S-adenosyl-methionine (SAM) as the methyl donor and removed by protein phosphatase methylesterase 1 (PME1). For PP2A, methylation dictates regulatory subunit selection and thereby downstream phosphorylation signaling. Intriguingly, there are four families of PP2A regulatory subunits, each exhibiting different levels of methylation sensitivity. Thus, changes in PP2A methylation stoichiometry alters the complement of PP2A holoenzymes in cells and creates distinct modes of kinase opposition. Importantly, selective inactivation of PP2A signaling through the deregulation of methylation is observed in several diseases, most prominently Alzheimer's disease (AD). In this review, we focus on how carboxyl-terminal methylation of the PP2A subfamily (PP2A, PP4, and PP6) regulates holoenzyme function and thereby phosphorylation signaling, with an emphasis on AD.
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Affiliation(s)
- Isha Nasa
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth College, Hanover, NH, U.S.A
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center at Dartmouth, Lebanon, NH, U.S.A
| | - Arminja N Kettenbach
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth College, Hanover, NH, U.S.A
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center at Dartmouth, Lebanon, NH, U.S.A
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35
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Hao J, Ci X, Wang Y, Choi SYC, Sullivan SE, Xue H, Wu R, Dong X, Haegert AM, Collins CC, Lin D, Wang Y. GRB10 sustains AR activity by interacting with PP2A in prostate cancer cells. Int J Cancer 2020; 148:469-480. [PMID: 33038264 DOI: 10.1002/ijc.33335] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 09/06/2020] [Accepted: 09/30/2020] [Indexed: 01/22/2023]
Abstract
Prostate cancer (PCa) progression is driven by androgen receptor (AR) signaling. Unfortunately, androgen-deprivation therapy and the use of even more potent AR pathway inhibitors (ARPIs) cannot bring about a cure. ARPI resistance (ie, castration-resistant PCa, CRPC) will inevitably develop. Previously, we demonstrated that GRB10 is an AR transcriptionally repressed gene that functionally contributes to CRPC development and ARPI resistance. GRB10 expression is elevated prior to CRPC development in our patient-derived xenograft models and is significantly upregulated in clinical CRPC samples. Here, we analyzed transcriptomic data from GRB10 knockdown in PCa cells and found that AR signaling is downregulated. While the mRNA expression of AR target genes decreased upon GRB10 knockdown, AR expression was not affected at the mRNA or protein level. We further found that phosphorylation of AR serine 81 (S81), which is critical for AR transcriptional activity, is decreased by GRB10 knockdown and increased by its overexpression. Luciferase assay using GRB10-knockdown cells also indicate reduced AR activity. Immunoprecipitation coupled with mass spectrometry revealed an interaction between GRB10 and the PP2A complex, which is a known phosphatase of AR. Further validations and analyses showed that GRB10 binds to the PP2Ac catalytic subunit with its PH domain. Mechanistically, GRB10 knockdown increased PP2Ac protein stability, which in turn decreased AR S81 phosphorylation and reduced AR activity. Our findings indicate a reciprocal feedback between GRB10 and AR signaling, implying the importance of GRB10 in PCa progression.
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Affiliation(s)
- Jun Hao
- Vancouver Prostate Centre, Department of Urologic Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Experimental Therapeutics, BC Cancer Agency, Vancouver, British Columbia, Canada
| | - Xinpei Ci
- Vancouver Prostate Centre, Department of Urologic Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Experimental Therapeutics, BC Cancer Agency, Vancouver, British Columbia, Canada
| | - Yong Wang
- Vancouver Prostate Centre, Department of Urologic Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Urology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Stephen Yiu Chuen Choi
- Vancouver Prostate Centre, Department of Urologic Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Experimental Therapeutics, BC Cancer Agency, Vancouver, British Columbia, Canada
| | - Sarah E Sullivan
- Vancouver Prostate Centre, Department of Urologic Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Kinesiology and Physical Education, McGill University, Quebec, Canada
| | - Hui Xue
- Department of Experimental Therapeutics, BC Cancer Agency, Vancouver, British Columbia, Canada
| | - Rebecca Wu
- Department of Experimental Therapeutics, BC Cancer Agency, Vancouver, British Columbia, Canada
| | - Xin Dong
- Department of Experimental Therapeutics, BC Cancer Agency, Vancouver, British Columbia, Canada
| | - Anne M Haegert
- Vancouver Prostate Centre, Department of Urologic Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Colin C Collins
- Vancouver Prostate Centre, Department of Urologic Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Dong Lin
- Vancouver Prostate Centre, Department of Urologic Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Experimental Therapeutics, BC Cancer Agency, Vancouver, British Columbia, Canada
| | - Yuzhuo Wang
- Vancouver Prostate Centre, Department of Urologic Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Experimental Therapeutics, BC Cancer Agency, Vancouver, British Columbia, Canada
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36
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The Greatwall kinase safeguards the genome integrity by affecting the kinome activity in mitosis. Oncogene 2020; 39:6816-6840. [PMID: 32978522 PMCID: PMC7605441 DOI: 10.1038/s41388-020-01470-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 08/21/2020] [Accepted: 09/10/2020] [Indexed: 12/19/2022]
Abstract
Progression through mitosis is balanced by the timely regulation of phosphorylation and dephosphorylation events ensuring the correct segregation of chromosomes before cytokinesis. This balance is regulated by the opposing actions of CDK1 and PP2A, as well as the Greatwall kinase/MASTL. MASTL is commonly overexpressed in cancer, which makes it a potential therapeutic anticancer target. Loss of Mastl induces multiple chromosomal errors that lead to the accumulation of micronuclei and multilobulated cells in mitosis. Our analyses revealed that loss of Mastl leads to chromosome breaks and abnormalities impairing correct segregation. Phospho-proteomic data for Mastl knockout cells revealed alterations in proteins implicated in multiple processes during mitosis including double-strand DNA damage repair. In silico prediction of the kinases with affected activity unveiled NEK2 to be regulated in the absence of Mastl. We uncovered that, RAD51AP1, involved in regulation of homologous recombination, is phosphorylated by NEK2 and CDK1 but also efficiently dephosphorylated by PP2A/B55. Our results suggest that MastlKO disturbs the equilibrium of the mitotic phosphoproteome that leads to the disruption of DNA damage repair and triggers an accumulation of chromosome breaks even in noncancerous cells.
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37
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AKT Regulates Mitotic Progression of Mammalian Cells by Phosphorylating MASTL, Leading to Protein Phosphatase 2A Inactivation. Mol Cell Biol 2020; 40:MCB.00366-18. [PMID: 32123010 DOI: 10.1128/mcb.00366-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 02/25/2020] [Indexed: 12/15/2022] Open
Abstract
Microtubule-associated serine/threonine kinase like (MASTL), also known as Greatwall (Gwl) kinase, has an important role in the regulation of mitosis. By inhibiting protein phosphatase 2A (PP2A), it plays a crucial role in activating one of the most important mitotic kinases, known as cyclin-dependent kinase 1 (CDK1). MASTL has been seen to be upregulated in various types of cancers and is also involved in tumor recurrence. It is activated by CDK1 through phosphorylations in the activation/T-loop, but the complete mechanism of its activation is still unclear. Here, we report that AKT phosphorylates MASTL at residue T299, which plays a critical role in its activation. Our results suggest that AKT increases CDK1-mediated phosphorylation and hence the activity of MASTL, which, in turn, promotes mitotic progression through PP2A inhibition. We also show that the oncogenic potential of AKT is augmented by MASTL activation, since AKT-mediated proliferation in colorectal cell lines can be attenuated by inhibiting and/or silencing MASTL. In brief, we report that AKT plays an important role in the progression of mitosis in mammalian cells and that it does so through the phosphorylation and activation of MASTL.
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38
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Leonard D, Huang W, Izadmehr S, O'Connor CM, Wiredja DD, Wang Z, Zaware N, Chen Y, Schlatzer DM, Kiselar J, Vasireddi N, Schüchner S, Perl AL, Galsky MD, Xu W, Brautigan DL, Ogris E, Taylor DJ, Narla G. Selective PP2A Enhancement through Biased Heterotrimer Stabilization. Cell 2020; 181:688-701.e16. [PMID: 32315618 DOI: 10.1016/j.cell.2020.03.038] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 12/04/2019] [Accepted: 03/17/2020] [Indexed: 12/15/2022]
Abstract
Impairment of protein phosphatases, including the family of serine/threonine phosphatases designated PP2A, is essential for the pathogenesis of many diseases, including cancer. The ability of PP2A to dephosphorylate hundreds of proteins is regulated by over 40 specificity-determining regulatory "B" subunits that compete for assembly and activation of heterogeneous PP2A heterotrimers. Here, we reveal how a small molecule, DT-061, specifically stabilizes the B56α-PP2A holoenzyme in a fully assembled, active state to dephosphorylate selective substrates, such as its well-known oncogenic target, c-Myc. Our 3.6 Å structure identifies molecular interactions between DT-061 and all three PP2A subunits that prevent dissociation of the active enzyme and highlight inherent mechanisms of PP2A complex assembly. Thus, our findings provide fundamental insights into PP2A complex assembly and regulation, identify a unique interfacial stabilizing mode of action for therapeutic targeting, and aid in the development of phosphatase-based therapeutics tailored against disease specific phospho-protein targets.
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Affiliation(s)
- Daniel Leonard
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA; Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Wei Huang
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Sudeh Izadmehr
- Division of Hematology and Medical Oncology, Department of Medicine, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Pathology, Molecular and Cell-Based Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Caitlin M O'Connor
- Division of Genetic Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48105, USA; Rogel Cancer Center, University of Michigan, Ann Arbor, MI 48109, USA
| | - Danica D Wiredja
- Department of Nutrition, Center for Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Zhizhi Wang
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Nilesh Zaware
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Yinghua Chen
- PEPCC Facility, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106, USA
| | - Daniela M Schlatzer
- Department of Nutrition, Center for Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Janna Kiselar
- Department of Nutrition, Center for Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Nikhil Vasireddi
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Stefan Schüchner
- Center for Medical Biochemistry, Max Perutz Labs, Medical University of Vienna, Dr. Bohr-Gasse 9/2, Vienna 1030, Austria
| | - Abbey L Perl
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Matthew D Galsky
- Division of Hematology and Medical Oncology, Department of Medicine, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Wenqing Xu
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - David L Brautigan
- Department of Microbiology, Immunology, and Cancer Biology, Center for Cell Signaling, University of Virginia, Charlottesville, VA 22903, USA
| | - Egon Ogris
- Center for Medical Biochemistry, Max Perutz Labs, Medical University of Vienna, Dr. Bohr-Gasse 9/2, Vienna 1030, Austria
| | - Derek J Taylor
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA; Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106, USA.
| | - Goutham Narla
- Division of Genetic Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48105, USA; Rogel Cancer Center, University of Michigan, Ann Arbor, MI 48109, USA.
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Akiyama H, Iwasaki Y, Yamada S, Kamiguchi H, Sakakibara SI. Control of cell migration by the novel protein phosphatase-2A interacting protein inka2. Cell Tissue Res 2020; 380:527-537. [DOI: 10.1007/s00441-020-03169-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 01/08/2020] [Indexed: 12/12/2022]
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Kim JW, Berrios C, Kim M, Schade AE, Adelmant G, Yeerna H, Damato E, Iniguez AB, Florens L, Washburn MP, Stegmaier K, Gray NS, Tamayo P, Gjoerup O, Marto JA, DeCaprio J, Hahn WC. STRIPAK directs PP2A activity toward MAP4K4 to promote oncogenic transformation of human cells. eLife 2020; 9:53003. [PMID: 31913126 PMCID: PMC6984821 DOI: 10.7554/elife.53003] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/07/2020] [Indexed: 12/13/2022] Open
Abstract
Alterations involving serine-threonine phosphatase PP2A subunits occur in a range of human cancers, and partial loss of PP2A function contributes to cell transformation. Displacement of regulatory B subunits by the SV40 Small T antigen (ST) or mutation/deletion of PP2A subunits alters the abundance and types of PP2A complexes in cells, leading to transformation. Here, we show that ST not only displaces common PP2A B subunits but also promotes A-C subunit interactions with alternative B subunits (B’’’, striatins) that are components of the Striatin-interacting phosphatase and kinase (STRIPAK) complex. We found that STRN4, a member of STRIPAK, is associated with ST and is required for ST-PP2A-induced cell transformation. ST recruitment of STRIPAK facilitates PP2A-mediated dephosphorylation of MAP4K4 and induces cell transformation through the activation of the Hippo pathway effector YAP1. These observations identify an unanticipated role of MAP4K4 in transformation and show that the STRIPAK complex regulates PP2A specificity and activity. Cells maintain a fine balance of signals that promote or counter cell growth and division. Two sets of enzymes – called kinases and phosphatases – contribute to this balance. In general, kinases “switch on” other proteins by tagging them with a phosphate molecule. This process is called phosphorylation. Phosphatases, on the other hand, dephosphorylate these proteins, switching them off. Cancer cells often have mutations that activate kinases to drive cancer growth. The same cells can have mutations that inactivate the phosphatases or reduce their abundance. The roles of phosphatases in cancer are still being studied. One major hurdle in this research is that it is not always clear how they recognize the proteins they dephosphorylate. Protein phosphatase 2A (or PP2A for short) is one of the phosphatases that is often mutated or deleted in human cancers. Even just reduced levels of PP2A can promote cancer. Kim, Berrios, Kim, Schade et al. used an experimental trick to decrease the phosphatase activity of PP2A in human cells growing in a dish. Biochemical analysis of these cells showed that, as expected, many proteins were now in their phosphorylated states. Unexpectedly, however, some proteins were dephosphorylated under these conditions. One of these proteins was called MAP4K4. In the case of MAP4K4, the dephosphorylated state contributes to the growth of the cancer cell. Kim et al. carried out further genetic and biochemical experiments to show that, in these cells, PP2A and MAP4K4 stay physically connected to one another. This connection was enabled by a group of proteins called the STRIPAK complex. The STRIPAK proteins directed the remaining PP2A towards MAP4K4. Low levels or activity of PP2A could, therefore, promote cancer in a different way. Taken together, PP2A is not a single phosphatase that always turns proteins off, but rather is a dual switch that turns off some proteins while turning on others. Future experiments will explore to what extent these findings also apply in tumors. Information about how mutations in PP2A affect human cancers could suggest new targets for cancer drugs.
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Affiliation(s)
- Jong Wook Kim
- Broad Institute of Harvard and MIT, Cambridge, United States.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States.,Division of Medical Genetics, School of Medicine, University of California, San Diego, San Diego, United States.,Moores Cancer Center, University of California, San Diego, San Diego, United States
| | - Christian Berrios
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States.,Program in Virology, Graduate School of Arts and Sciences, Harvard University, Cambridge, United States
| | - Miju Kim
- Broad Institute of Harvard and MIT, Cambridge, United States.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States
| | - Amy E Schade
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States.,Program in Virology, Graduate School of Arts and Sciences, Harvard University, Cambridge, United States
| | - Guillaume Adelmant
- Department of Cancer Biology and Blais Proteomics Center, Dana-Farber Cancer Institute, Boston, United States.,Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, United States.,Department of Oncologic Pathology, Dana-Farber Cancer Institute, Boston, United States
| | - Huwate Yeerna
- Division of Medical Genetics, School of Medicine, University of California, San Diego, San Diego, United States
| | - Emily Damato
- Broad Institute of Harvard and MIT, Cambridge, United States
| | - Amanda Balboni Iniguez
- Broad Institute of Harvard and MIT, Cambridge, United States.,Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, United States
| | - Laurence Florens
- Stowers Institute for Medical Research, Kansas City, United States
| | - Michael P Washburn
- Stowers Institute for Medical Research, Kansas City, United States.,Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, United States
| | - Kim Stegmaier
- Broad Institute of Harvard and MIT, Cambridge, United States.,Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, United States
| | - Nathanael S Gray
- Department of Cancer Biology and Blais Proteomics Center, Dana-Farber Cancer Institute, Boston, United States
| | - Pablo Tamayo
- Division of Medical Genetics, School of Medicine, University of California, San Diego, San Diego, United States.,Moores Cancer Center, University of California, San Diego, San Diego, United States
| | - Ole Gjoerup
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States
| | - Jarrod A Marto
- Department of Cancer Biology and Blais Proteomics Center, Dana-Farber Cancer Institute, Boston, United States.,Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, United States.,Department of Oncologic Pathology, Dana-Farber Cancer Institute, Boston, United States
| | - James DeCaprio
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States.,Program in Virology, Graduate School of Arts and Sciences, Harvard University, Cambridge, United States.,Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, United States
| | - William C Hahn
- Broad Institute of Harvard and MIT, Cambridge, United States.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States.,Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, United States
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O'Connor CM, Leonard D, Wiredja D, Avelar RA, Wang Z, Schlatzer D, Bryson B, Tokala E, Taylor SE, Upadhyay A, Sangodkar J, Gingras AC, Westermarck J, Xu W, DiFeo A, Brautigan DL, Haider S, Jackson M, Narla G. Inactivation of PP2A by a recurrent mutation drives resistance to MEK inhibitors. Oncogene 2020; 39:703-717. [PMID: 31541192 PMCID: PMC6980487 DOI: 10.1038/s41388-019-1012-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 06/26/2019] [Accepted: 08/09/2019] [Indexed: 12/27/2022]
Abstract
The serine/threonine Protein Phosphatase 2A (PP2A) functions as a tumor suppressor by negatively regulating multiple oncogenic signaling pathways. The canonical PP2A holoenzyme comprises a scaffolding subunit (PP2A Aα/β), which serves as the platform for binding of both the catalytic C subunit and one regulatory B subunit. Somatic heterozygous missense mutations in PPP2R1A, the gene encoding the PP2A Aα scaffolding subunit, have been identified across multiple cancer types, but the effects of the most commonly mutated residue, Arg-183, on PP2A function have yet to be fully elucidated. In this study, we used a series of cellular and in vivo models and discovered that the most frequent Aα R183W mutation formed alternative holoenzymes by binding of different PP2A regulatory subunits compared with wild-type Aα, suggesting a rededication of PP2A functions. Unlike wild-type Aα, which suppressed tumorigenesis, the R183W mutant failed to suppress tumor growth in vivo through activation of the MAPK pathway in RAS-mutant transformed cells. Furthermore, cells expressing R183W were less sensitive to MEK inhibitors. Taken together, our results demonstrate that the R183W mutation in PP2A Aα scaffold abrogates the tumor suppressive actions of PP2A, thereby potentiating oncogenic signaling and reducing drug sensitivity of RAS-mutant cells.
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Affiliation(s)
- Caitlin M O'Connor
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA
| | - Daniel Leonard
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Danica Wiredja
- Center for Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, OH, USA
| | - Rita A Avelar
- Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Zhizhi Wang
- Department of Biological Structure, University of Washington, Seattle, WA, USA
| | - Daniela Schlatzer
- Center for Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, OH, USA
| | - Benjamin Bryson
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, USA
| | - Eesha Tokala
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, USA
| | - Sarah E Taylor
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Aditya Upadhyay
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, USA
| | - Jaya Sangodkar
- Department of Internal Medicine: Genetic Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Jukka Westermarck
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland
| | - Wenqing Xu
- Department of Biological Structure, University of Washington, Seattle, WA, USA
| | - Analisa DiFeo
- Department of Pathology, University of Michigan, Ann Arbor, MI, USA
- Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, USA
| | - David L Brautigan
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Shozeb Haider
- Department of Pharmaceutical and Biological Chemistry, University College London, London, UK
| | - Mark Jackson
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, USA
| | - Goutham Narla
- Department of Internal Medicine: Genetic Medicine, University of Michigan, Ann Arbor, MI, USA.
- Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA.
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42
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A fail-safe system to prevent oncogenesis by senescence is targeted by SV40 small T antigen. Oncogene 2019; 39:2170-2186. [PMID: 31819167 DOI: 10.1038/s41388-019-1139-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 11/23/2019] [Accepted: 11/27/2019] [Indexed: 12/14/2022]
Abstract
Whereas large T antigen (LT) of simian virus 40 (SV40) promotes oncogenesis by inactivating the tumor suppressor proteins p53 and pRb, SV40 small T antigen (ST) has been thought to be dispensable for this process. However, here we show that LT promotes both oncogenic growth and senescence in human cells expressing oncogenic Ras and that this latter effect is antagonized by ST. Inactivation of p53 by LT alone promoted the senescence-associated secretory phenotype (SASP), whereas the additional expression of ST attenuated this phenotype, allowing cells to avoid oncogene-induced senescence (OIS) and thereby promoting efficient oncogenesis. ST interacts with and inhibits the function of heterochromatin protein 1-binding protein 3 (HP1BP3), a positive regulator of global microRNA biogenesis, and it thereby triggers aberrant upregulation of B-cell translocation gene 2 (BTG2), which is essential for prevention of SASP and OIS by ST. Collectively, our results indicate that the HP1BP3-BTG2 axis constitutes a fail-safe system to prevent oncogenesis by means of OIS induction, and that this system is hijacked by ST.
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43
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Nader CP, Cidem A, Verrills NM, Ammit AJ. Protein phosphatase 2A (PP2A): a key phosphatase in the progression of chronic obstructive pulmonary disease (COPD) to lung cancer. Respir Res 2019; 20:222. [PMID: 31623614 PMCID: PMC6798356 DOI: 10.1186/s12931-019-1192-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 09/20/2019] [Indexed: 02/06/2023] Open
Abstract
Lung cancer (LC) has the highest relative risk of development as a comorbidity of chronic obstructive pulmonary disease (COPD). The molecular mechanisms that mediate chronic inflammation and lung function impairment in COPD have been identified in LC. This suggests the two diseases are more linked than once thought. Emerging data in relation to a key phosphatase, protein phosphatase 2A (PP2A), and its regulatory role in inflammatory and tumour suppression in both disease settings suggests that it may be critical in the progression of COPD to LC. In this review, we uncover the importance of the functional and active PP2A holoenzyme in the context of both diseases. We describe PP2A inactivation via direct and indirect means and explore the actions of two key PP2A endogenous inhibitors, cancerous inhibitor of PP2A (CIP2A) and inhibitor 2 of PP2A (SET), and the role they play in COPD and LC. We explain how dysregulation of PP2A in COPD creates a favourable inflammatory micro-environment and promotes the initiation and progression of tumour pathogenesis. Finally, we highlight PP2A as a druggable target in the treatment of COPD and LC and demonstrate the potential of PP2A re-activation as a strategy to halt COPD disease progression to LC. Although further studies are required to elucidate if PP2A activity in COPD is a causal link for LC progression, studies focused on the potential of PP2A reactivating agents to reduce the risk of LC formation in COPD patients will be pivotal in improving clinical outcomes for both COPD and LC patients in the future.
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Affiliation(s)
- Cassandra P Nader
- Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia
| | - Aylin Cidem
- Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia
| | - Nicole M Verrills
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, 2308, Australia
- Priority Research Centre for Cancer Research, Innovation & Translation, Faculty of Health & Medicine, Hunter Medical Research Institute, New Lambton Heights, NSW, 2305, Australia
| | - Alaina J Ammit
- Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia.
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia.
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44
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Tsuji S, Ohama T, Nakagawa T, Sato K. Efficacy of an anti-cancer strategy targeting SET in canine osteosarcoma. J Vet Med Sci 2019; 81:1424-1430. [PMID: 31527340 PMCID: PMC6863715 DOI: 10.1292/jvms.19-0311] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Osteosarcoma (OSA) is the most common bone tumor in dogs. Protein phosphatase 2A (PP2A), an evolutionary conserved serine/threonine protein phosphatase, is a crucial tumor suppressor. SET is a PP2A inhibitory protein that directly interacts with PP2A and suppresses its phosphatase activity. SET has been reported as a contributor of wide range of human and dog tumor malignancies. However, the role of SET in canine OSA (cOSA) remains unknown. In this study, we investigated the role of SET in cOSA by using 2 cOSA cell lines: POS (primary origin) and HM-POS (metastatic origin). Knockdown (KD) of SET expression was noted to slightly suppress POS cell proliferation only. Furthermore, SET KD effectively suppressed colony formation ability of both POS and HM-POS cells. SET KD was observed to repress ERK1/2, mTOR, E2F1, and NF-κB signaling in HM-POS cells, whereas it inhibited only ERK1/2 signaling in POS. Further, it was observed that SET-targeting drug, FTY720, exerted anti-cancer effects in both POS and HM-POS cells. Moreover, the drug also enhanced the anti-cancer effect of cisplatin. The data suggested that a combination therapy, based on SET targeting drugs and cisplatin, could be a potent strategy for cOSA.
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Affiliation(s)
- Shunya Tsuji
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
| | - Takashi Ohama
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
| | - Takayuki Nakagawa
- The Laboratory of Veterinary Surgery and the Veterinary Medical Center, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Koichi Sato
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
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45
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Wang L, Bai J, Wang Q, Ge G, Lin J, Xu N, Xu C, Xu Y, Wang Y, Geng D. Inhibition of protein phosphatase 2A attenuates titanium-particle induced suppression of bone formation. Int J Biol Macromol 2019; 142:142-151. [PMID: 31521663 DOI: 10.1016/j.ijbiomac.2019.09.084] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 09/11/2019] [Indexed: 12/12/2022]
Abstract
Peri-prosthetic osteolysis (PPO) often generates after total joint arthroplasty, which can bring implant failure and following revision surgery. Wear debris shed from prostheses strongly enhances bone resorption and attenuates bone formation in osteolytic process. We previously proved that suppression of protein phosphatase 2A (PP2A), a major serine-threonine phosphatase, inhibited wear-debris-induced osteoclastogenesis and alleviated local osteolysis. Whether PP2A inhibition facilitates osteoblastogenesis and bone formation in the osteolytic sites remains unclear. Here, we observed that PP2A inhibition with a selective inhibitor attenuated particle-induced bone destruction by accelerating osteoblast differentiation and promoting bone regeneration. Meanwhile, we proved inhibition of PP2A alleviated the inhibition of osteogenic differentiation by titanium particles in MC3T3-E1 cells. In addition, PP2A inhibition increased β-catenin expression and enhanced β-catenin nuclear translocation, compared with that in the vehicle group. ICG-001, a specific inhibitor of β-catenin, was further applied and was found to weaken the effect of PP2A inhibition on β-catenin expression and nuclear translocation. Therefore, we demonstrated PP2A inhibition exerts protective effects on osteogenic differentiation mainly by activating Wnt/β-catenin signaling pathway. Thus, all the results further revealed PP2A could be a promising target for treating PPO and other bone related diseases.
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Affiliation(s)
- Liangliang Wang
- Department of Orthopaedics, The Affiliated Changzhou No. 2 People's Hospital of Nanjing Medical University, Changzhou, PR China
| | - Jiaxiang Bai
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, PR China
| | - Qing Wang
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, PR China
| | - Gaoran Ge
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, PR China
| | - Jiayi Lin
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, PR China
| | - Nanwei Xu
- Department of Orthopaedics, The Affiliated Changzhou No. 2 People's Hospital of Nanjing Medical University, Changzhou, PR China
| | - Chao Xu
- Department of Orthopaedics, The Affiliated Changzhou No. 2 People's Hospital of Nanjing Medical University, Changzhou, PR China
| | - Yaozeng Xu
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, PR China
| | - Yuji Wang
- Department of Orthopaedics, The Affiliated Changzhou No. 2 People's Hospital of Nanjing Medical University, Changzhou, PR China; Department of Orthopedic Surgery and Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, United States.
| | - Dechun Geng
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, PR China.
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46
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Antao NV, Marcet-Ortega M, Cifani P, Kentsis A, Foley EA. A Cancer-Associated Missense Mutation in PP2A-Aα Increases Centrosome Clustering during Mitosis. iScience 2019; 19:74-82. [PMID: 31357169 PMCID: PMC6664223 DOI: 10.1016/j.isci.2019.07.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 06/27/2019] [Accepted: 07/12/2019] [Indexed: 12/21/2022] Open
Abstract
Whole-genome doubling (WGD) is common early in tumorigenesis. WGD doubles ploidy and centrosome number. In the ensuing mitoses, excess centrosomes form a multipolar spindle, resulting in a lethal multipolar cell division. To survive, cells must cluster centrosomes to allow bipolar cell division. Cancer cells are often more proficient at centrosome clustering than untransformed cells, but the mechanism behind increased clustering ability is not well understood. Heterozygous missense mutations in PPP2R1A, which encodes the alpha isoform of the "scaffolding" subunit of PP2A (PP2A-Aα), positively correlate with WGD. We introduced a heterozygous hotspot mutation, P179R, into PPP2R1A in human RPE-1 cells. PP2A-AαP179R decreases PP2A assembly and intracellular targeting in mitosis. Strikingly, PP2A-AαP179R enhances centrosome clustering when centrosome number is increased either by cytokinesis failure or centrosome amplification, likely through PP2A-Aα loss of function. Thus cancer-associated mutations in PP2A-Aα may increase cellular fitness after WGD by enhancing centrosome clustering.
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Affiliation(s)
- Noelle V Antao
- Program in Biochemistry and Structural Biology, Cell and Developmental Biology, and Molecular Biology, Weill Cornell Medicine Graduate School of Medical Sciences, Cornell University, New York, NY 10065, USA; Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Marina Marcet-Ortega
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Paolo Cifani
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Alex Kentsis
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Emily A Foley
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
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47
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Li Y, Li Z, Zhu WG. Molecular Mechanisms of Epigenetic Regulators as Activatable Targets in Cancer Theranostics. Curr Med Chem 2019; 26:1328-1350. [PMID: 28933282 DOI: 10.2174/0929867324666170921101947] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 05/24/2017] [Accepted: 06/09/2017] [Indexed: 12/11/2022]
Abstract
Epigenetics is defined as somatically inheritable changes that are not accompanied by alterations in DNA sequence. Epigenetics encompasses DNA methylation, covalent histone modifications, non-coding RNA as well as nucleosome remodeling. Notably, abnormal epigenetic changes play a critical role in cancer development including malignant transformation, metastasis, prognosis, drug resistance and tumor recurrence, which can provide effective targets for cancer prognosis, diagnosis and therapy. Understanding these changes provide effective means for cancer diagnosis and druggable targets for better clinical applications. Histone modifications and related enzymes have been found to correlate well with cancer incidence and prognosis in recent years. Dysregulated expression or mutation of histone modification enzymes and histone modification status abnormalities have been considered to play essential roles in tumorigenesis and clinical outcomes of cancer treatment. Some of the histone modification inhibitors have been extensively employed in clinical practice and many others are still under laboratory research or pre-clinical assessment. Here we summarize the important roles of epigenetics, especially histone modifications in cancer diagnostics and therapeutics, and also discuss the developmental implications of activatable epigenetic targets in cancer theranostics.
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Affiliation(s)
- Yinglu Li
- Shenzhen University School of Medicine, Shenzhen 518060, China.,Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing 100191, China
| | - Zhiming Li
- Shenzhen University School of Medicine, Shenzhen 518060, China.,Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing 100191, China
| | - Wei-Guo Zhu
- Shenzhen University School of Medicine, Shenzhen 518060, China.,Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing 100191, China
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48
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El Taweel M, Gawdat RM, Abdelfattah R. Prognostic Impact of PPP2R5C Gene Expression in Adult Acute Myeloid Leukemia Patients with Normal Cytogenetics. Indian J Hematol Blood Transfus 2019; 36:37-46. [PMID: 32158086 DOI: 10.1007/s12288-019-01142-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 05/28/2019] [Indexed: 10/26/2022] Open
Abstract
Protein Phosphatase 2A (PP2A) is a crucial regulator of the cellular signalling pathways, proliferation, cell cycle checkpoints and apoptosis. The PPP2R5C gene encodes PP2A regulatory B56γ subunit. Malignant transformation may occur, if mRNA of PPP2R5C is functionally deregulated, structurally altered, decreased or overexpressed. Therefore, the purpose of the study was to examine PPP2R5C mRNA expression, evaluate its association with the different clinical and haematological parameters and determine its prognostic impact in Egyptian adult acute myeloid leukaemia patients with normal cytogenetics (CN-AML). Peripheral blood samples of 50 de novo CN-AML patients and 20 age- and gender-matched healthy controls were examined for PPP2R5C expression by Quantitative Real Time-Polymerase Chain Reaction. The expression levels of PPP2R5C mRNA were significantly higher in the CN-AML samples than in the control samples (P ≤ 0.001). There was a statistical significant difference between the low and high expression levels of PPP2R5C with regard to age (P = 0.005, r = - 0.447, P = 0.001). The patients with an unfavourable response to induction chemotherapy had significant higher PPP2R5C expression levels than those with a favourable response (P = 0.002). There was a significant influence of high PPP2R5C expression levels on the overall survival and progression free survival (P = 0.03, 0.026), respectively. PPP2R5C overexpression is an adverse prognostic factor which affects leukaemogenesis in the CN-AML, it may predict the disease progression and overall survival during the follow-up of the patients.
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Affiliation(s)
- Maha El Taweel
- 1Clinical Pathology Department, National Cancer Institute, Cairo University, Cairo, Egypt
| | - Rania M Gawdat
- 2Clinical and Chemical Pathology Department, Faculty of Medicine, Beni-Suef Teaching Hospital, Beni-Suef University, Beni- Suef, Egypt
| | - Rafaat Abdelfattah
- 3Department of Medical Oncology, National Cancer Institute, Cairo University, Cairo, Egypt
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Remmerie M, Janssens V. PP2A: A Promising Biomarker and Therapeutic Target in Endometrial Cancer. Front Oncol 2019; 9:462. [PMID: 31214504 PMCID: PMC6558005 DOI: 10.3389/fonc.2019.00462] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 05/14/2019] [Indexed: 12/14/2022] Open
Abstract
Over the last decade, the use of targeted therapies has immensely increased in the treatment of cancer. However, treatment for endometrial carcinomas (ECs) has lagged behind, although potential molecular markers have been identified. This is particularly problematic for the type II ECs, since these aggressive tumors are usually not responsive toward the current standard therapies. Therefore, type II ECs are responsible for most EC-related deaths, indicating the need for new treatment options. Interestingly, molecular analyses of type II ECs have uncovered frequent genetic alterations (up to 40%) in PPP2R1A, encoding the Aα subunit of the tumor suppressive heterotrimeric protein phosphatase type 2A (PP2A). PPP2R1A mutations were also reported in type I ECs and other common gynecologic cancers, albeit at much lower frequencies (0-7%). Nevertheless, PP2A inactivation in the latter cancer types is common via other mechanisms, in particular by increased expression of Cancerous Inhibitor of PP2A (CIP2A) and PP2A Methylesterase-1 (PME-1) proteins. In this review, we discuss the therapeutic potential of direct and indirect PP2A targeting compounds, possibly in combination with other anti-cancer drugs, in EC. Furthermore, we investigate the potential of the PP2A status as a predictive and/or prognostic marker for type I and II ECs.
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Affiliation(s)
| | - Veerle Janssens
- Laboratory of Protein Phosphorylation and Proteomics, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
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Taylor SE, O'Connor CM, Wang Z, Shen G, Song H, Leonard D, Sangodkar J, LaVasseur C, Avril S, Waggoner S, Zanotti K, Armstrong AJ, Nagel C, Resnick K, Singh S, Jackson MW, Xu W, Haider S, DiFeo A, Narla G. The Highly Recurrent PP2A Aα-Subunit Mutation P179R Alters Protein Structure and Impairs PP2A Enzyme Function to Promote Endometrial Tumorigenesis. Cancer Res 2019; 79:4242-4257. [PMID: 31142515 DOI: 10.1158/0008-5472.can-19-0218] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 04/12/2019] [Accepted: 05/22/2019] [Indexed: 11/16/2022]
Abstract
Somatic mutation of the protein phosphatase 2A (PP2A) Aα-subunit gene PPP2R1A is highly prevalent in high-grade endometrial carcinoma. The structural, molecular, and biological basis by which the most recurrent endometrial carcinoma-specific mutation site P179 facilitates features of endometrial carcinoma malignancy has yet to be fully determined. Here, we used a series of structural, biochemical, and biological approaches to investigate the impact of the P179R missense mutation on PP2A function. Enhanced sampling molecular dynamics simulations showed that arginine-to-proline substitution at the P179 residue changes the protein's stable conformation profile. A crystal structure of the tumor-derived PP2A mutant revealed marked changes in A-subunit conformation. Binding to the PP2A catalytic subunit was significantly impaired, disrupting holoenzyme formation and enzymatic activity. Cancer cells were dependent on PP2A disruption for sustained tumorigenic potential, and restoration of wild-type Aα in a patient-derived P179R-mutant cell line restored enzyme function and significantly attenuated tumorigenesis and metastasis in vivo. Furthermore, small molecule-mediated therapeutic reactivation of PP2A significantly inhibited tumorigenicity in vivo. These outcomes implicate PP2A functional inactivation as a critical component of high-grade endometrial carcinoma disease pathogenesis. Moreover, they highlight PP2A reactivation as a potential therapeutic strategy for patients who harbor P179R PPP2R1A mutations. SIGNIFICANCE: This study characterizes a highly recurrent, disease-specific PP2A PPP2R1A mutation as a driver of endometrial carcinoma and a target for novel therapeutic development.See related commentary by Haines and Huang, p. 4009.
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Affiliation(s)
- Sarah E Taylor
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Caitlin M O'Connor
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Zhizhi Wang
- Department of Biological Structure, University of Washington, Seattle, Washington
| | - Guobo Shen
- Department of Biological Structure, University of Washington, Seattle, Washington
| | - Haichi Song
- Department of Pharmaceutical and Biological Chemistry, UCL School of Pharmacy, University College London, London, United Kingdom
| | - Daniel Leonard
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Jaya Sangodkar
- Division of Genetic Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Corinne LaVasseur
- School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Stefanie Avril
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio.,Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio
| | - Steven Waggoner
- Department of Obstetrics and Gynecology, University Hospitals of Cleveland, Cleveland, Ohio
| | - Kristine Zanotti
- Department of Obstetrics and Gynecology, University Hospitals of Cleveland, Cleveland, Ohio
| | - Amy J Armstrong
- Department of Obstetrics and Gynecology, University Hospitals of Cleveland, Cleveland, Ohio
| | - Christa Nagel
- Department of Obstetrics and Gynecology, University Hospitals of Cleveland, Cleveland, Ohio
| | - Kimberly Resnick
- Department of Obstetrics and Gynecology, MetroHealth, Cleveland, Ohio
| | - Sareena Singh
- Department of Obstetrics and Gynecology, Aultman Hospital, Canton, Ohio
| | - Mark W Jackson
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio.,Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio
| | - Wenqing Xu
- Department of Biological Structure, University of Washington, Seattle, Washington
| | - Shozeb Haider
- Department of Pharmaceutical and Biological Chemistry, UCL School of Pharmacy, University College London, London, United Kingdom
| | - Analisa DiFeo
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, Michigan.,Department of Pathology, University of Michigan, Ann Arbor, Michigan.,Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
| | - Goutham Narla
- Division of Genetic Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan. .,Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
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