1
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Sanz-Flores M, Ruiz-Torres M, Aguirre-Portolés C, El Bakkali A, Salvador-Barberó B, Villarroya-Beltri C, Ortega S, Megías D, Gerlich DW, Álvarez-Fernández M, Malumbres M. PP2A-B55 phosphatase counteracts Ki-67-dependent chromosome individualization during mitosis. Cell Rep 2024; 43:114494. [PMID: 39003739 DOI: 10.1016/j.celrep.2024.114494] [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: 11/02/2023] [Revised: 05/10/2024] [Accepted: 06/26/2024] [Indexed: 07/16/2024] Open
Abstract
Cell cycle progression is regulated by the orderly balance between kinase and phosphatase activities. PP2A phosphatase holoenzymes containing the B55 family of regulatory B subunits function as major CDK1-counteracting phosphatases during mitotic exit in mammals. However, the identification of the specific mitotic roles of these PP2A-B55 complexes has been hindered by the existence of multiple B55 isoforms. Here, through the generation of loss-of-function genetic mouse models for the two ubiquitous B55 isoforms (B55α and B55δ), we report that PP2A-B55α and PP2A-B55δ complexes display overlapping roles in controlling the dynamics of proper chromosome individualization and clustering during mitosis. In the absence of PP2A-B55 activity, mitotic cells display increased chromosome individualization in the presence of enhanced phosphorylation and perichromosomal loading of Ki-67. These data provide experimental evidence for a regulatory mechanism by which the balance between kinase and PP2A-B55 phosphatase activity controls the Ki-67-mediated spatial organization of the mass of chromosomes during mitosis.
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Affiliation(s)
- María Sanz-Flores
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Miguel Ruiz-Torres
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | | | - Aicha El Bakkali
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | | | | | | | | | - Daniel W Gerlich
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter, Vienna, Austria
| | - Mónica Álvarez-Fernández
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain; Health Research Institute of Asturias (ISPA), University Institute of Oncology of Asturias (IUOPA), University of Oviedo, Oviedo, Spain.
| | - Marcos Malumbres
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain; Vall d'Hebron Institute of Oncology (VHIO), Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain; ICREA, Barcelona, Spain.
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2
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Wasserman JS, Faezov B, Patel KR, Kurimchak AM, Palacio SM, Glass DJ, Fowle H, McEwan BC, Xu Q, Zhao Z, Cressey L, Johnson N, Duncan JS, Kettenbach AN, Dunbrack RL, Graña X. FAM122A ensures cell cycle interphase progression and checkpoint control by inhibiting B55α/PP2A through helical motifs. Nat Commun 2024; 15:5776. [PMID: 38982062 PMCID: PMC11233601 DOI: 10.1038/s41467-024-50015-7] [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: 03/05/2023] [Accepted: 06/26/2024] [Indexed: 07/11/2024] Open
Abstract
The Ser/Thr protein phosphatase 2 A (PP2A) regulates the dephosphorylation of many phosphoproteins. Substrate recognition are mediated by B regulatory subunits. Here, we report the identification of a substrate conserved motif [RK]-V-x-x-[VI]-R in FAM122A, an inhibitor of B55α/PP2A. This motif is necessary for FAM122A binding to B55α, and computational structure prediction suggests the motif, which is helical, blocks substrate docking to the same site. In this model, FAM122A also spatially constrains substrate access by occluding the catalytic subunit. Consistently, FAM122A functions as a competitive inhibitor as it prevents substrate binding and dephosphorylation of CDK substrates by B55α/PP2A in cell lysates. FAM122A deficiency in human cell lines reduces the proliferation rate, cell cycle progression, and hinders G1/S and intra-S phase cell cycle checkpoints. FAM122A-KO in HEK293 cells attenuates CHK1 and CHK2 activation in response to replication stress. Overall, these data strongly suggest that FAM122A is a short helical motif (SHeM)-dependent, substrate-competitive inhibitor of B55α/PP2A that suppresses multiple functions of B55α in the DNA damage response and in timely progression through the cell cycle interphase.
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Affiliation(s)
- Jason S Wasserman
- Fels Cancer Institute for Personalized Medicine. Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Bulat Faezov
- Fox Chase Cancer Center, Temple Health, Philadelphia, PA, USA
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russian Federation
| | - Kishan R Patel
- Fels Cancer Institute for Personalized Medicine. Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | | | - Seren M Palacio
- Fels Cancer Institute for Personalized Medicine. Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - David J Glass
- Fox Chase Cancer Center, Temple Health, Philadelphia, PA, USA
| | - Holly Fowle
- Fels Cancer Institute for Personalized Medicine. Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Brennan C McEwan
- Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Medical Center Drive, Lebanon, NH, USA
| | - Qifang Xu
- Fox Chase Cancer Center, Temple Health, Philadelphia, PA, USA
| | - Ziran Zhao
- Fels Cancer Institute for Personalized Medicine. Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Lauren Cressey
- Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Medical Center Drive, Lebanon, NH, USA
| | - Neil Johnson
- Fox Chase Cancer Center, Temple Health, Philadelphia, PA, USA
| | - James S Duncan
- Fox Chase Cancer Center, Temple Health, Philadelphia, PA, USA
| | - Arminja N Kettenbach
- Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Medical Center Drive, Lebanon, NH, USA
| | | | - Xavier Graña
- Fels Cancer Institute for Personalized Medicine. Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA.
- Fox Chase Cancer Center, Temple Health, Philadelphia, PA, USA.
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3
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Singh D, Qiu Z, Jonathan SM, Fa P, Thomas H, Prasad CB, Cai S, Wang JJ, Yan C, Zhang X, Venere M, Li Z, Sizemore ST, Wang QE, Zhang J. PP2A B55α inhibits epithelial-mesenchymal transition via regulation of Slug expression in non-small cell lung cancer. Cancer Lett 2024; 598:217110. [PMID: 38986733 DOI: 10.1016/j.canlet.2024.217110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Revised: 07/03/2024] [Accepted: 07/04/2024] [Indexed: 07/12/2024]
Abstract
PP2A B55α, encoded by PPP2R2A, acts as a regulatory subunit of the serine/threonine phosphatase PP2A. Despite a frequent loss of heterozygosity of PPP2R2A in cases of non-small cell lung cancer (NSCLC), research on PP2A B55α's functions remains limited and controversial. To investigate the biological roles of PP2A B55α, we conducted bulk RNA-sequencing to assess the impact of PPP2R2A knockdown using two shRNAs in a NSCLC cell line. Gene set enrichment analysis (GSEA) of the RNA-sequencing data revealed significant enrichment of the epithelial-mesenchymal transition (EMT) pathway, with SNAI2 (the gene encoding Slug) emerging as one of the top candidates. Our findings demonstrate that PP2A B55α suppresses EMT, as PPP2R2A deficiency through knockdown or homozygous or hemizygous depletion promotes EMT and metastatic behavior in NSCLC cells, as evidenced by changes in EMT biomarkers, invasion and migration abilities, as well as metastasis in a tail vein assay. Mechanistically, PP2A B55α inhibits EMT by downregulating SNAI2 expression via the GSK3β-β-catenin pathway. Importantly, PPP2R2A deficiency also slows cell proliferation by disrupting DNA replication, particularly in PPP2R2A-/- cells. Furthermore, PPP2R2A deficiency, especially PPP2R2A-/- cells, leads to an increase in the cancer stem cell population, which correlates with enhanced resistance to chemotherapy. Overall, the decrease in PP2A B55α levels due to hemizygous/homozygous depletion heightens EMT and the metastatic or stemness/drug resistance potential of NSCLC cells despite their proliferation disadvantage. Our study highlights the significance of PP2A B55α in EMT and metastasis and suggests that targeting EMT/stemness could be a potential therapeutic strategy for treating PPP2R2A-deficient NSCLC.
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Affiliation(s)
- Deepika Singh
- The Department of Radiation Oncology, The Ohio State University Comprehensive Cancer Center and College of Medicine, Columbus, OH, United States
| | - Zhaojun Qiu
- The Department of Radiation Oncology, The Ohio State University Comprehensive Cancer Center and College of Medicine, Columbus, OH, United States
| | - Spehar M Jonathan
- The Department of Radiation Oncology, The Ohio State University Comprehensive Cancer Center and College of Medicine, Columbus, OH, United States
| | - Pengyan Fa
- The Department of Radiation Oncology, The Ohio State University Comprehensive Cancer Center and College of Medicine, Columbus, OH, United States
| | - Hannah Thomas
- The Ohio State University, Columbus, OH, United States
| | - Chandra Bhushan Prasad
- The Department of Radiation Oncology, The Ohio State University Comprehensive Cancer Center and College of Medicine, Columbus, OH, United States
| | - Shurui Cai
- The Department of Radiation Oncology, The Ohio State University Comprehensive Cancer Center and College of Medicine, Columbus, OH, United States
| | - Jing J Wang
- The Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center and College of Medicine, Columbus, OH, United States
| | - Chunhong Yan
- Georgia Cancer Center, Augusta University, Augusta, GA, United States
| | - Xiaoli Zhang
- Center for Biostatistics, The Ohio State University, United States; Department of Biomedical Informatics, College of Medicine, The Ohio State University, United States
| | - Monica Venere
- The Department of Radiation Oncology, The Ohio State University Comprehensive Cancer Center and College of Medicine, Columbus, OH, United States; The James Comprehensive Cancer Center, Pelotonia Institute for Immuno-Oncology, The Ohio State University, Columbus, OH, United States
| | - Zaibo Li
- Department of Pathology, The Ohio State University Wexner Medical Center, College of Medicine, Columbus, OH, 43210, United States
| | - Steven T Sizemore
- The Department of Radiation Oncology, The Ohio State University Comprehensive Cancer Center and College of Medicine, Columbus, OH, United States
| | - Qi-En Wang
- The Department of Radiation Oncology, The Ohio State University Comprehensive Cancer Center and College of Medicine, Columbus, OH, United States
| | - Junran Zhang
- The Department of Radiation Oncology, The Ohio State University Comprehensive Cancer Center and College of Medicine, Columbus, OH, United States; The James Comprehensive Cancer Center, Pelotonia Institute for Immuno-Oncology, The Ohio State University, Columbus, OH, United States; The James Comprehensive Cancer Center, Center for Metabolism, United States.
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4
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Yalçin Z, Lam SY, Peuscher MH, van der Torre J, Zhu S, Iyengar PV, Salas-Lloret D, de Krijger I, Moatti N, van der Lugt R, Falcone M, Cerutti A, Bleijerveld OB, Hoekman L, González-Prieto R, Jacobs JJL. UBE2D3 facilitates NHEJ by orchestrating ATM signalling through multi-level control of RNF168. Nat Commun 2024; 15:5032. [PMID: 38866770 PMCID: PMC11169547 DOI: 10.1038/s41467-024-49431-6] [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: 04/05/2024] [Accepted: 06/03/2024] [Indexed: 06/14/2024] Open
Abstract
Maintenance of genome integrity requires tight control of DNA damage response (DDR) signalling and repair, with phosphorylation and ubiquitination representing key elements. How these events are coordinated to achieve productive DNA repair remains elusive. Here we identify the ubiquitin-conjugating enzyme UBE2D3 as a regulator of ATM kinase-induced DDR that promotes non-homologous end-joining (NHEJ) at telomeres. UBE2D3 contributes to DDR-induced chromatin ubiquitination and recruitment of the NHEJ-promoting factor 53BP1, both mediated by RNF168 upon ATM activation. Additionally, UBE2D3 promotes NHEJ by limiting RNF168 accumulation and facilitating ATM-mediated phosphorylation of KAP1-S824. Mechanistically, defective KAP1-S824 phosphorylation and telomeric NHEJ upon UBE2D3-deficiency are linked to RNF168 hyperaccumulation and aberrant PP2A phosphatase activity. Together, our results identify UBE2D3 as a multi-level regulator of NHEJ that orchestrates ATM and RNF168 activities. Moreover, they reveal a negative regulatory circuit in the DDR that is constrained by UBE2D3 and consists of RNF168- and phosphatase-mediated restriction of KAP1 phosphorylation.
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Affiliation(s)
- Zeliha Yalçin
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, the Netherlands
| | - Shiu Yeung Lam
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, the Netherlands
| | - Marieke H Peuscher
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, the Netherlands
| | - Jaco van der Torre
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, the Netherlands
| | - Sha Zhu
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, the Netherlands
| | - Prasanna V Iyengar
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, the Netherlands
| | - Daniel Salas-Lloret
- Department of Cell and Chemical Biology, Leiden University Medical Center, Einthovenweg 20, 2333 ZC, Leiden, the Netherlands
| | - Inge de Krijger
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, the Netherlands
| | - Nathalie Moatti
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, the Netherlands
| | - Ruben van der Lugt
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, the Netherlands
| | - Mattia Falcone
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, the Netherlands
| | - Aurora Cerutti
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, the Netherlands
| | - Onno B Bleijerveld
- Proteomics Facility, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, the Netherlands
| | - Liesbeth Hoekman
- Proteomics Facility, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, the Netherlands
| | - Román González-Prieto
- Department of Cell and Chemical Biology, Leiden University Medical Center, Einthovenweg 20, 2333 ZC, Leiden, the Netherlands
- Andalusian Center for Molecular Biology and regenerative Medicine (CABIMER), Universidad de Sevilla-CSIC-Universidad-Pablo de Olavide, Sevilla, Spain
- Departamento de Biología Celular, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
| | - Jacqueline J L Jacobs
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, the Netherlands.
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5
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Liang X, Zhang H, Shang W, Wang M, Li J, Zhao Y, Fang C. PPP2CA Inhibition Promotes Ferroptosis Sensitivity Through AMPK/SCD1 Pathway in Colorectal Cancer. Dig Dis Sci 2024; 69:2083-2095. [PMID: 38637456 DOI: 10.1007/s10620-024-08416-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 03/28/2024] [Indexed: 04/20/2024]
Abstract
PURPOSE Colorectal cancer (CRC) is a very common malignancy of the digestive system. Despite a variety of treatments including surgery, chemotherapeutic and targeted drugs, the prognosis for patients with CRC is still unsatisfactory and the mortality remains high. Protein phosphorylation plays an essential role in tumorigenesis and progression and is also crucial for protein to act with proper functions. Ferroptosis is found widely involved in various diseases especially tumors as a newly identified programmed cell death. METHODS In our study, we aimed at PPP2CA as a prospective target which may play a crucial role in CRC progression. In one hand, knockdown of PPP2CA significantly enhanced the malignant phenotype in HCT116. In the other hand, knockdown of PPP2CA significantly enhanced Erastin-induced ferroptosis as well. RESULTS Specifically, knockdown of PPP2CA in HCT116 significantly increased the relative level of malondialdehyde (MDA), reactive oxygen species (ROS) and Fe2+, and decreased GSH/GSSG ratio after the treatment of certain concentration of Erastin. Besides, we found that the inhibition of PPP2CA further led to the suppression of SCD1 expression in CRC cells in a AMPK-dependent way. CONCLUSION Ultimately, we conclude that PPP2CA may regulate Erastin-induced ferroptosis through AMPK/SCD1 signaling pathway.
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Affiliation(s)
- Xiaojie Liang
- Department of General Surgery, The Affiliated Jiangning Hospital of Nanjing Medical University, 169 Hushan Road, Nanjing, 211100, China
| | - Hui Zhang
- Department of General Surgery, The Affiliated Jiangning Hospital of Nanjing Medical University, 169 Hushan Road, Nanjing, 211100, China
| | - Weiwei Shang
- Department of General Surgery, The Affiliated Jiangning Hospital of Nanjing Medical University, 169 Hushan Road, Nanjing, 211100, China
| | - Mingming Wang
- Department of General Surgery, The Affiliated Jiangning Hospital of Nanjing Medical University, 169 Hushan Road, Nanjing, 211100, China
| | - Jun Li
- Department of General Surgery, The Affiliated Jiangning Hospital of Nanjing Medical University, 169 Hushan Road, Nanjing, 211100, China
| | - Yunzhao Zhao
- Department of General Surgery, The Affiliated Jinling Hospital of Nanjing Medical University, 305 East Zhongshan Road, Nanjing, 210002, China
| | - Chao Fang
- Central Laboratory, The Affiliated Jiangning Hospital of Nanjing Medical University, 169 Hushan Road, Nanjing, 211100, China.
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6
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Hughes CJ, Alderman C, Wolin AR, Fields KM, Zhao R, Ford HL. All eyes on Eya: A unique transcriptional co-activator and phosphatase in cancer. Biochim Biophys Acta Rev Cancer 2024; 1879:189098. [PMID: 38555001 PMCID: PMC11111358 DOI: 10.1016/j.bbcan.2024.189098] [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: 12/15/2023] [Revised: 03/26/2024] [Accepted: 03/27/2024] [Indexed: 04/02/2024]
Abstract
The Eya family of proteins (consisting of Eyas1-4 in mammals) play vital roles in embryogenesis by regulating processes such as proliferation, migration/invasion, cellular survival and pluripotency/plasticity of epithelial and mesenchymal states. Eya proteins carry out such diverse functions through a unique combination of transcriptional co-factor, Tyr phosphatase, and PP2A/B55α-mediated Ser/Thr phosphatase activities. Since their initial discovery, re-expression of Eyas has been observed in numerous tumor types, where they are known to promote tumor progression through a combination of their transcriptional and enzymatic activities. Eya proteins thus reinstate developmental processes during malignancy and represent a compelling class of therapeutic targets for inhibiting tumor progression.
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Affiliation(s)
- Connor J Hughes
- Medical Scientist Training Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States of America; Department of Pharmacology, University of Colorado Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045, United States of America
| | - Christopher Alderman
- Medical Scientist Training Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States of America; Molecular Biology Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States of America; Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States of America
| | - Arthur R Wolin
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045, United States of America; Molecular Biology Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States of America
| | - Kaiah M Fields
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045, United States of America; Molecular Biology Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States of America
| | - Rui Zhao
- Medical Scientist Training Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States of America; Molecular Biology Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States of America; Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States of America.
| | - Heide L Ford
- Medical Scientist Training Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States of America; Department of Pharmacology, University of Colorado Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045, United States of America; Molecular Biology Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States of America.
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7
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Nagelli S, Westermarck J. CIP2A coordinates phosphosignaling, mitosis, and the DNA damage response. Trends Cancer 2024; 10:52-64. [PMID: 37793965 DOI: 10.1016/j.trecan.2023.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 08/18/2023] [Accepted: 09/04/2023] [Indexed: 10/06/2023]
Abstract
Human cancers share requirements for phosphorylation-dependent signaling, mitotic hyperactivity, and survival after DNA damage. The oncoprotein CIP2A (cancerous inhibitor of PP2A) can coordinate all these cancer cell characteristics. In addition to controlling cancer cell phosphoproteomes via inhibition of protein phosphatase PP2A, CIP2A directly interacts with the DNA damage protein TopBP1 (topoisomerase II-binding protein 1). Consequently, CIP2A allows DNA-damaged cells to enter mitosis and is essential for mitotic cells that are defective in homologous recombination (HR)-mediated DNA repair (e.g., BRCA mutants). The CIP2A-TopBP1 complex is also important for clustering fragmented chromosomes at mitosis. Clinically, CIP2A is a disease driver for basal-like triple-negative breast cancer (BL-TNBC) and a promising cancer therapy target across many cancer types.
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Affiliation(s)
- Srikar Nagelli
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland; Institute of Biomedicine and FICANWest Cancer Center, University of Turku, Turku, Finland
| | - Jukka Westermarck
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland; Institute of Biomedicine and FICANWest Cancer Center, University of Turku, Turku, Finland; InFLAMES Research Flagship Center, University of Turku, Turku, Finland.
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8
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Li YM, He HW, Zhang N. Targeting Protein Phosphatases for the Treatment of Chronic Liver Disease. Curr Drug Targets 2024; 25:171-189. [PMID: 38213163 DOI: 10.2174/0113894501278886231221092522] [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: 10/12/2023] [Revised: 11/27/2023] [Accepted: 11/29/2023] [Indexed: 01/13/2024]
Abstract
There exists a huge number of patients suffering from chronic liver disease worldwide. As a disease with high incidence and mortality worldwide, strengthening the research on the pathogenesis of chronic liver disease and the development of novel drugs is an important issue related to the health of all human beings. Phosphorylation modification of proteins plays a crucial role in cellular signal transduction, and phosphatases are involved in the development of liver diseases. Therefore, this article summarized the important role of protein phosphatases in chronic liver disease with the aim of facilitating the development of drugs targeting protein phosphatases for the treatment of chronic liver disease.
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Affiliation(s)
- Yi-Ming Li
- NHC Key Laboratory of Biotechnology for Microbial Drugs, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
| | - Hong-Wei He
- NHC Key Laboratory of Biotechnology for Microbial Drugs, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
| | - Na Zhang
- NHC Key Laboratory of Biotechnology for Microbial Drugs, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
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9
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Huang GJ, Parry TK, McLaughlin WA. Assessment of the Performances of the Protein Modeling Techniques Participating in CASP15 Using a Structure-Based Functional Site Prediction Approach: ResiRole. Bioengineering (Basel) 2023; 10:1377. [PMID: 38135968 PMCID: PMC10740689 DOI: 10.3390/bioengineering10121377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 11/27/2023] [Accepted: 11/28/2023] [Indexed: 12/24/2023] Open
Abstract
BACKGROUND Model quality assessments via computational methods which entail comparisons of the modeled structures to the experimentally determined structures are essential in the field of protein structure prediction. The assessments provide means to benchmark the accuracies of the modeling techniques and to aid with their development. We previously described the ResiRole method to gauge model quality principally based on the preservation of the structural characteristics described in SeqFEATURE functional site prediction models. METHODS We apply ResiRole to benchmark modeling group performances in the Critical Assessment of Structure Prediction experiment, round 15. To gauge model quality, a normalized Predicted Functional site Similarity Score (PFSS) was calculated as the average of one minus the absolute values of the differences of the functional site prediction probabilities, as found for the experimental structures versus those found at the corresponding sites in the structure models. RESULTS The average PFSS per modeling group (gPFSS) correlates with standard quality metrics, and can effectively be used to rank the accuracies of the groups. For the free modeling (FM) category, correlation coefficients of the Local Distance Difference Test (LDDT) and Global Distance Test-Total Score (GDT-TS) metrics with gPFSS were 0.98239 and 0.87691, respectively. An example finding for a specific group is that the gPFSS for EMBER3D was higher than expected based on the predictive relationship between gPFSS and LDDT. We infer the result is due to the use of constraints imprinted by function that are a part of the EMBER3D methodology. Also, we find functional site predictions that may guide further functional characterizations of the respective proteins. CONCLUSION The gPFSS metric provides an effective means to assess and rank the performances of the structure prediction techniques according to their abilities to accurately recount the structural features at predicted functional sites.
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Affiliation(s)
| | | | - William A. McLaughlin
- Department of Medical Education, Geisinger Commonwealth School of Medicine, 525 Pine Street, Scranton, PA 18509, USA (T.K.P.)
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10
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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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11
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Perl AL, Koetsier JL, Green KJ. PP2A-B55alpha controls keratinocyte adhesion through dephosphorylation of the Desmoplakin C-terminus. Sci Rep 2023; 13:12720. [PMID: 37543698 PMCID: PMC10404246 DOI: 10.1038/s41598-023-37874-8] [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: 11/07/2022] [Accepted: 06/28/2023] [Indexed: 08/07/2023] Open
Abstract
Critical for the maintenance of epidermal integrity and function are attachments between intermediate filaments (IF) and intercellular junctions called desmosomes. The desmosomal cytoplasmic plaque protein desmoplakin (DP) is essential for anchoring IF to the junction. DP-IF interactions are regulated by a phospho-regulatory motif within the DP C-terminus controlling keratinocyte intercellular adhesion. Here we identify the protein phosphatase 2A (PP2A)-B55α holoenzyme as the major serine/threonine phosphatase regulating DP's C-terminus and consequent intercellular adhesion. Using a combination of chemical and genetic approaches, we show that the PP2A-B55α holoenzyme interacts with DP at intercellular membranes in 2D- and 3D- epidermal models and human skin samples. Our experiments demonstrate that PP2A-B55α regulates the phosphorylation status of junctional DP and is required for maintaining strong desmosome-mediated intercellular adhesion. These data identify PP2A-B55α as part of a regulatory module capable of tuning intercellular adhesion strength and a candidate disease target in desmosome-related disorders of the skin and heart.
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Affiliation(s)
- Abbey L Perl
- Department of Pathology, Feinberg School of Medicine, Northwestern University, 303 E Chicago Ave., Chicago, IL, 60611, USA
| | - Jennifer L Koetsier
- Department of Pathology, Feinberg School of Medicine, Northwestern University, 303 E Chicago Ave., Chicago, IL, 60611, USA
| | - Kathleen J Green
- Department of Pathology, Feinberg School of Medicine, Northwestern University, 303 E Chicago Ave., Chicago, IL, 60611, USA.
- Department of Dermatology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL, USA.
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12
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Nguyen H, Kettenbach AN. Substrate and phosphorylation site selection by phosphoprotein phosphatases. Trends Biochem Sci 2023; 48:713-725. [PMID: 37173206 PMCID: PMC10523993 DOI: 10.1016/j.tibs.2023.04.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 04/11/2023] [Accepted: 04/13/2023] [Indexed: 05/15/2023]
Abstract
Dynamic protein phosphorylation and dephosphorylation are essential regulatory mechanisms that ensure proper cellular signaling and biological functions. Deregulation of either reaction has been implicated in several human diseases. Here, we focus on the mechanisms that govern the specificity of the dephosphorylation reaction. Most cellular serine/threonine dephosphorylation is catalyzed by 13 highly conserved phosphoprotein phosphatase (PPP) catalytic subunits, which form hundreds of holoenzymes by binding to regulatory and scaffolding subunits. PPP holoenzymes recognize phosphorylation site consensus motifs and interact with short linear motifs (SLiMs) or structural elements distal to the phosphorylation site. We review recent advances in understanding the mechanisms of PPP site-specific dephosphorylation preference and substrate recruitment and highlight examples of their interplay in the regulation of cell division.
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Affiliation(s)
- Hieu Nguyen
- Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth College, Hanover, NH 03755, USA
| | - Arminja N Kettenbach
- Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth College, Hanover, NH 03755, USA; Dartmouth Cancer Center, Lebanon, NH 03756, USA.
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13
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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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14
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Patil RS, Kovacs-Kasa A, Gorshkov BA, Fulton DJR, Su Y, Batori RK, Verin AD. Serine/Threonine Protein Phosphatases 1 and 2A in Lung Endothelial Barrier Regulation. Biomedicines 2023; 11:1638. [PMID: 37371733 PMCID: PMC10296329 DOI: 10.3390/biomedicines11061638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 05/28/2023] [Accepted: 06/02/2023] [Indexed: 06/29/2023] Open
Abstract
Vascular barrier dysfunction is characterized by increased permeability and inflammation of endothelial cells (ECs), which are prominent features of acute lung injury (ALI), acute respiratory distress syndrome (ARDS), and sepsis, and a major complication of the SARS-CoV-2 infection and COVID-19. Functional impairment of the EC barrier and accompanying inflammation arises due to microbial toxins and from white blood cells of the lung as part of a defensive action against pathogens, ischemia-reperfusion or blood product transfusions, and aspiration syndromes-based injury. A loss of barrier function results in the excessive movement of fluid and macromolecules from the vasculature into the interstitium and alveolae resulting in pulmonary edema and collapse of the architecture and function of the lungs, and eventually culminates in respiratory failure. Therefore, EC barrier integrity, which is heavily dependent on cytoskeletal elements (mainly actin filaments, microtubules (MTs), cell-matrix focal adhesions, and intercellular junctions) to maintain cellular contacts, is a critical requirement for the preservation of lung function. EC cytoskeletal remodeling is regulated, at least in part, by Ser/Thr phosphorylation/dephosphorylation of key cytoskeletal proteins. While a large body of literature describes the role of phosphorylation of cytoskeletal proteins on Ser/Thr residues in the context of EC barrier regulation, the role of Ser/Thr dephosphorylation catalyzed by Ser/Thr protein phosphatases (PPases) in EC barrier regulation is less documented. Ser/Thr PPases have been proposed to act as a counter-regulatory mechanism that preserves the EC barrier and opposes EC contraction. Despite the importance of PPases, our knowledge of the catalytic and regulatory subunits involved, as well as their cellular targets, is limited and under-appreciated. Therefore, the goal of this review is to discuss the role of Ser/Thr PPases in the regulation of lung EC cytoskeleton and permeability with special emphasis on the role of protein phosphatase 1 (PP1) and protein phosphatase 2A (PP2A) as major mammalian Ser/Thr PPases. Importantly, we integrate the role of PPases with the structural dynamics of the cytoskeleton and signaling cascades that regulate endothelial cell permeability and inflammation.
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Affiliation(s)
- Rahul S. Patil
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Anita Kovacs-Kasa
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Boris A. Gorshkov
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - David J. R. Fulton
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
- Department of Pharmacology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Yunchao Su
- Department of Pharmacology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Robert K. Batori
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Alexander D. Verin
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
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15
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Wasserman JS, Faezov B, Patel KR, Kurimchak AN, Palacio SM, Fowle H, McEwan BC, Xu Q, Zhao Z, Cressey L, Johnson N, Duncan JS, Kettenbach AN, Dunbrack RL, Graña X. FAM122A ensures cell cycle interphase progression and checkpoint control as a SLiM-dependent substrate-competitive inhibitor to the B55⍺/PP2A phosphatase. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.06.531310. [PMID: 36945596 PMCID: PMC10028791 DOI: 10.1101/2023.03.06.531310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
The Ser/Thr protein phosphatase 2A (PP2A) is a highly conserved collection of heterotrimeric holoenzymes responsible for the dephosphorylation of many regulated phosphoproteins. Substrate recognition and the integration of regulatory cues are mediated by B regulatory subunits that are complexed to the catalytic subunit (C) by a scaffold protein (A). PP2A/B55 substrate recruitment was thought to be mediated by charge-charge interactions between the surface of B55α and its substrates. Challenging this view, we recently discovered a conserved SLiM [ RK ]- V -x-x-[ VI ]- R in a range of proteins, including substrates such as the retinoblastoma-related protein p107 and TAU (Fowle et al. eLife 2021;10:e63181). Here we report the identification of this SLiM in FAM122A, an inhibitor of B55α/PP2A. This conserved SLiM is necessary for FAM122A binding to B55α in vitro and in cells. Computational structure prediction with AlphaFold2 predicts an interaction consistent with the mutational and biochemical data and supports a mechanism whereby FAM122A uses the 'SLiM' in the form of a short α-helix to dock to the B55α top groove. In this model, FAM122A spatially constrains substrate access by occluding the catalytic subunit with a second α-helix immediately adjacent to helix 1. Consistently, FAM122A functions as a competitive inhibitor as it prevents binding of substrates in in vitro competition assays and the dephosphorylation of CDK substrates by B55α/PP2A in cell lysates. Ablation of FAM122A in human cell lines reduces the rate of proliferation, progression through cell cycle transitions and abrogates G1/S and intra-S phase cell cycle checkpoints. FAM122A-KO in HEK293 cells results in attenuation of CHK1 and CHK2 activation in response to replication stress. Overall, these data strongly suggest that FAM122A is a 'SLiM'-dependent, substrate-competitive inhibitor of B55α/PP2A that suppresses multiple functions of B55α in the DNA damage response and in timely progression through the cell cycle interphase.
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16
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Zhou Y, Fan K, Dou N, Li L, Wang J, Chen J, Li Y, Gao Y. YTHDF2 exerts tumor-suppressor roles in gastric cancer via up-regulating PPP2CA independently of m 6A modification. Biol Proced Online 2023; 25:6. [PMID: 36870954 PMCID: PMC9985201 DOI: 10.1186/s12575-023-00195-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 02/24/2023] [Indexed: 03/06/2023] Open
Abstract
BACKGROUND YTHDF2 is one of important readers of N6-methyladenosine (m6A) modification on RNA. Growing evidence implicates that YTHDF2 takes an indispensable part in the regulation of tumorigenesis and metastasis in different cancers, but its biological functions and underlying mechanisms remain elusive in gastric cancer (GC). AIM To investigate the clinical relevance and biological function of YTHDF2 in GC. RESULTS Compared with matched normal stomach tissues, YTHDF2 expression was markedly decreased in gastric cancer tissues. The expression level of YTHDF2 was inversely associated with gastric cancer patients' tumor size, AJCC classification and prognosis. Functionally, YTHDF2 reduction facilitated gastric cancer cell growth and migration in vitro and in vivo, whereas YTHDF2 overexpression exhibited opposite phenotypes. Mechanistically, YTHDF2 enhanced expression of PPP2CA, the catalytic subunit of PP2A (Protein phosphatase 2A), in an m6A-independent manner, and silencing of PPP2CA antagonized the anti-tumor effects caused by overexpression of YTHDF2 in GC cells. CONCLUSION These findings demonstrate that YTHDF2 is down-regulated in GC and its down-regulation promotes GC progression via a possible mechanism involving PPP2CA expression, suggesting that YTHDF2 may be a hopeful biomarker for diagnosis and an unrevealed treatment target for GC.
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Affiliation(s)
- Ying Zhou
- Department of Oncology, Shanghai East Hospital, School of Medicine, Tongji University, 150 Ji-Mo Rd., Shanghai, 200120, China
| | - Kailing Fan
- Department of Oncology, Shanghai East Hospital, School of Medicine, Tongji University, 150 Ji-Mo Rd., Shanghai, 200120, China
| | - Ning Dou
- Department of Oncology, Shanghai East Hospital, School of Medicine, Tongji University, 150 Ji-Mo Rd., Shanghai, 200120, China
| | - Li Li
- Department of Oncology, Shanghai East Hospital, School of Medicine, Tongji University, 150 Ji-Mo Rd., Shanghai, 200120, China
| | - Jialin Wang
- Department of Oncology, Shanghai East Hospital, School of Medicine, Tongji University, 150 Ji-Mo Rd., Shanghai, 200120, China
| | - Jingde Chen
- Department of Oncology, Shanghai East Hospital Ji'an Hospital, Ji'an City, 343000, Jiangxi Province, China.,School of Medicine, Tongji University, Shanghai, 200120, China
| | - Yandong Li
- Department of Oncology, Shanghai East Hospital, School of Medicine, Tongji University, 150 Ji-Mo Rd., Shanghai, 200120, China.
| | - Yong Gao
- Department of Oncology, Shanghai East Hospital, School of Medicine, Tongji University, 150 Ji-Mo Rd., Shanghai, 200120, China.
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17
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Peris I, Romero-Murillo S, Martínez-Balsalobre E, Farrington CC, Arriazu E, Marcotegui N, Jiménez-Muñoz M, Alburquerque-Prieto C, Torres-López A, Fresquet V, Martínez-Climent JA, Mateos MC, Cayuela ML, Narla G, Odero MD, Vicente C. Activation of the PP2A-B56α heterocomplex synergizes with venetoclax therapies in AML through BCL2 and MCL1 modulation. Blood 2023; 141:1047-1059. [PMID: 36455198 PMCID: PMC10023731 DOI: 10.1182/blood.2022016466] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 11/18/2022] [Accepted: 11/18/2022] [Indexed: 12/02/2022] Open
Abstract
Venetoclax combination therapies are becoming the standard of care in acute myeloid leukemia (AML). However, the therapeutic benefit of these drugs in older/unfit patients is limited to only a few months, highlighting the need for more effective therapies. Protein phosphatase 2A (PP2A) is a tumor suppressor phosphatase with pleiotropic functions that becomes inactivated in ∼70% of AML cases. PP2A promotes cancer cell death by modulating the phosphorylation state in a variety of proteins along the mitochondrial apoptotic pathway. We therefore hypothesized that pharmacological PP2A reactivation could increase BCL2 dependency in AML cells and, thus, potentiate venetoclax-induced cell death. Here, by using 3 structurally distinct PP2A-activating drugs, we show that PP2A reactivation synergistically enhances venetoclax activity in AML cell lines, primary cells, and xenograft models. Through the use of gene editing tools and pharmacological approaches, we demonstrate that the observed therapeutic synergy relies on PP2A complexes containing the B56α regulatory subunit, of which expression dictates response to the combination therapy. Mechanistically, PP2A reactivation enhances venetoclax-driven apoptosis through simultaneous inhibition of antiapoptotic BCL2 and extracellular signal-regulated kinase signaling, with the latter decreasing MCL1 protein stability. Finally, PP2A targeting increases the efficacy of the clinically approved venetoclax and azacitidine combination in vitro, in primary cells, and in an AML patient-derived xenograft model. These preclinical results provide a scientific rationale for testing PP2A-activating drugs with venetoclax combinations in AML.
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Affiliation(s)
- Irene Peris
- Centro de Investigación Médica Aplicada, University of Navarra, Pamplona, Spain
- Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain
- Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
| | - Silvia Romero-Murillo
- Centro de Investigación Médica Aplicada, University of Navarra, Pamplona, Spain
- Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain
| | - Elena Martínez-Balsalobre
- Cancer and Aging Group, Hospital Universitario Virgen de la Arrixaca, and Instituto Murciano de Investigación Biosanitaria, Murcia, Spain
| | - Caroline C. Farrington
- Division of Genetic Medicine, Department of Internal Medicine, The University of Michigan Medical School, Ann Arbor, MI
| | - Elena Arriazu
- Centro de Investigación Médica Aplicada, University of Navarra, Pamplona, Spain
- Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
- Centro de Investigación Biomédica en Red de Oncología, Instituto de Salud Carlos III, Madrid, Spain
| | - Nerea Marcotegui
- Centro de Investigación Médica Aplicada, University of Navarra, Pamplona, Spain
| | - Marta Jiménez-Muñoz
- Centro de Investigación Médica Aplicada, University of Navarra, Pamplona, Spain
| | | | | | - Vicente Fresquet
- Centro de Investigación Médica Aplicada, University of Navarra, Pamplona, Spain
- Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
- Centro de Investigación Biomédica en Red de Oncología, Instituto de Salud Carlos III, Madrid, Spain
| | - Jose A. Martínez-Climent
- Centro de Investigación Médica Aplicada, University of Navarra, Pamplona, Spain
- Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
- Centro de Investigación Biomédica en Red de Oncología, Instituto de Salud Carlos III, Madrid, Spain
| | - Maria C. Mateos
- Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
- Hematology Service, Hospital Universitario de Navarra, Pamplona, Spain
| | - Maria L. Cayuela
- Cancer and Aging Group, Hospital Universitario Virgen de la Arrixaca, and Instituto Murciano de Investigación Biosanitaria, Murcia, Spain
| | - Goutham Narla
- Division of Genetic Medicine, Department of Internal Medicine, The University of Michigan Medical School, Ann Arbor, MI
| | - Maria D. Odero
- Centro de Investigación Médica Aplicada, University of Navarra, Pamplona, Spain
- Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain
- Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
- Centro de Investigación Biomédica en Red de Oncología, Instituto de Salud Carlos III, Madrid, Spain
| | - Carmen Vicente
- Centro de Investigación Médica Aplicada, University of Navarra, Pamplona, Spain
- Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain
- Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
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18
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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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19
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Su B, Lim D, Qi C, Zhang Z, Wang J, Zhang F, Dong C, Feng Z. VPA mediates bidirectional regulation of cell cycle progression through the PPP2R2A-Chk1 signaling axis in response to HU. Cell Death Dis 2023; 14:114. [PMID: 36781846 PMCID: PMC9925808 DOI: 10.1038/s41419-023-05649-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/31/2023] [Accepted: 02/02/2023] [Indexed: 02/15/2023]
Abstract
Cell cycle checkpoint kinases play a pivotal role in protecting against replicative stress. In this study, valproic acid (VPA), a histone deacetylase inhibitor (HDACi), was found to promote breast cancer MCF-7 cells to traverse into G2/M phase for catastrophic injury by promoting PPP2R2A (the B-regulatory subunit of Phosphatase PP2A) to facilitate the dephosphorylation of Chk1 at Ser317 and Ser345. By contrast, VPA protected normal 16HBE cells from HU toxicity through decreasing PPP2R2A expression and increasing Chk1 phosphorylation. The effect of VPA on PPP2R2A was at the post-transcription level through HDAC1/2. The in vitro results were affirmed in vivo. Patients with lower PPP2R2A expression and higher pChk1 expression showed significantly worse survival. PPP2R2A D197 and N181 are essential for PPP2R2A-Chk1 signaling and VPA-mediated bidirectional effect on augmenting HU-induced tumor cell death and protecting normal cells.
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Affiliation(s)
- Benyu Su
- Department of Occupational and Environmental Health, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - David Lim
- Translational Health Research Institute, School of Health Sciences, Western Sydney University, Campbelltown, NSW, Australia
- College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia
| | - Chenyang Qi
- Department of Occupational and Environmental Health, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Zhongwei Zhang
- Department of Occupational and Environmental Health, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Junxiao Wang
- Department of Occupational and Environmental Health, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Fengmei Zhang
- Department of Occupational and Environmental Health, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Chao Dong
- Department of Occupational and Environmental Health, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China.
| | - Zhihui Feng
- Department of Occupational and Environmental Health, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China.
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20
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Targeting protein phosphatases in cancer immunotherapy and autoimmune disorders. Nat Rev Drug Discov 2023; 22:273-294. [PMID: 36693907 PMCID: PMC9872771 DOI: 10.1038/s41573-022-00618-w] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/29/2022] [Indexed: 01/25/2023]
Abstract
Protein phosphatases act as key regulators of multiple important cellular processes and are attractive therapeutic targets for various diseases. Although extensive effort has been dedicated to phosphatase-targeted drug discovery, early expeditions for competitive phosphatase inhibitors were plagued by druggability issues, leading to the stigmatization of phosphatases as difficult targets. Despite challenges, persistent efforts have led to the identification of several drug-like, non-competitive modulators of some of these enzymes - including SH2 domain-containing protein tyrosine phosphatase 2, protein tyrosine phosphatase 1B, vascular endothelial protein tyrosine phosphatase and protein phosphatase 1 - reigniting interest in therapeutic targeting of phosphatases. Here, we discuss recent progress in phosphatase drug discovery, with emphasis on the development of selective modulators that exhibit biological activity. The roles and regulation of protein phosphatases in immune cells and their potential as powerful targets for immuno-oncology and autoimmunity indications are assessed.
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21
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Sanz‐Castillo B, Hurtado B, Vara‐Ciruelos D, El Bakkali A, Hermida D, Salvador‐Barbero B, Martínez‐Alonso D, González‐Martínez J, Santiveri C, Campos‐Olivas R, Ximénez‐Embún P, Muñoz J, Álvarez‐Fernández M, Malumbres M. The MASTL/PP2A cell cycle kinase-phosphatase module restrains PI3K-Akt activity in an mTORC1-dependent manner. EMBO J 2023; 42:e110833. [PMID: 36354735 PMCID: PMC9841333 DOI: 10.15252/embj.2022110833] [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: 02/01/2022] [Revised: 10/24/2022] [Accepted: 10/24/2022] [Indexed: 11/11/2022] Open
Abstract
The AKT-mTOR pathway is a central regulator of cell growth and metabolism. Upon sustained mTOR activity, AKT activity is attenuated by a feedback loop that restrains upstream signaling. However, how cells control the signals that limit AKT activity is not fully understood. Here, we show that MASTL/Greatwall, a cell cycle kinase that supports mitosis by phosphorylating the PP2A/B55 inhibitors ENSA/ARPP19, inhibits PI3K-AKT activity by sustaining mTORC1- and S6K1-dependent phosphorylation of IRS1 and GRB10. Genetic depletion of MASTL results in an inefficient feedback loop and AKT hyperactivity. These defects are rescued by the expression of phosphomimetic ENSA/ARPP19 or inhibition of PP2A/B55 phosphatases. MASTL is directly phosphorylated by mTORC1, thereby limiting the PP2A/B55-dependent dephosphorylation of IRS1 and GRB10 downstream of mTORC1. Downregulation of MASTL results in increased glucose uptake in vitro and increased glucose tolerance in adult mice, suggesting the relevance of the MASTL-PP2A/B55 kinase-phosphatase module in controlling AKT and maintaining metabolic homeostasis.
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Affiliation(s)
- Belén Sanz‐Castillo
- Cell Division and Cancer GroupSpanish National Cancer Research Centre (CNIO)MadridSpain
| | - Begoña Hurtado
- Cell Division and Cancer GroupSpanish National Cancer Research Centre (CNIO)MadridSpain
| | - Diana Vara‐Ciruelos
- Cell Division and Cancer GroupSpanish National Cancer Research Centre (CNIO)MadridSpain
| | - Aicha El Bakkali
- Cell Division and Cancer GroupSpanish National Cancer Research Centre (CNIO)MadridSpain
| | - Dario Hermida
- Cell Division and Cancer GroupSpanish National Cancer Research Centre (CNIO)MadridSpain
| | | | - Diego Martínez‐Alonso
- Cell Division and Cancer GroupSpanish National Cancer Research Centre (CNIO)MadridSpain
| | | | - Clara Santiveri
- Spectroscopy and Nuclear Magnetic Resonance UnitSpanish National Cancer Research Centre (CNIO)MadridSpain
| | - Ramón Campos‐Olivas
- Spectroscopy and Nuclear Magnetic Resonance UnitSpanish National Cancer Research Centre (CNIO)MadridSpain
| | | | - Javier Muñoz
- Proteomics UnitSpanish National Cancer Research Centre (CNIO)MadridSpain
| | - Mónica Álvarez‐Fernández
- Cell Division and Cancer GroupSpanish National Cancer Research Centre (CNIO)MadridSpain
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA)Instituto Universitario de Oncología del Principado de Asturias (IUOPA)OviedoSpain
| | - Marcos Malumbres
- Cell Division and Cancer GroupSpanish National Cancer Research Centre (CNIO)MadridSpain
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22
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Medley JC, Song MH. kin-3 genetically suppresses sur-6 in centrosome assembly during Caenorhabditis elegans embryogenesis. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.000791. [PMID: 36969515 PMCID: PMC10031309 DOI: 10.17912/micropub.biology.000791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 03/03/2023] [Accepted: 03/05/2023] [Indexed: 03/29/2023]
Abstract
Protein phosphorylation plays a critical role in cell cycle progression. In Caenorhabditis elegans , Casein Kinase II (CK2) negatively regulates centrosome assembly, and Protein Phosphatase 2A (PP2A) SUR-6 /B55 acts as a positive regulator of centrosome duplication, suggesting CK2 and PP2A SUR-6 /B55 play opposing roles in centrosome assembly. Here, we examined the genetic interaction between kin-3 , encoding the catalytic subunit of CK2, and sur-6 , encoding the PP2Aregulatory subunit SUR-6 /B55, in Caenorhabditis elegans embryos. Our results show that kin-3 (RNAi) partially restores normal centrosome duplication and embryonic viability to hypomorphic sur-6 mutants, suggesting that kin-3 genetically suppresses sur-6 in centrosome assembly during Caenorhabditis elegans embryogenesis.
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Affiliation(s)
- Jeffrey C. Medley
- Department of Biological Sciences, Oakland University, Rochester, Michigan, United States
| | - Mi Hye Song
- Department of Biological Sciences, Oakland University, Rochester, Michigan, United States
- Correspondence to: Mi Hye Song (
)
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23
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The repression of oncoprotein SET by the tumor suppressor p53 reveals a p53-SET-PP2A feedback loop for cancer therapy. SCIENCE CHINA. LIFE SCIENCES 2023; 66:81-93. [PMID: 35881220 DOI: 10.1007/s11427-021-2123-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 04/30/2022] [Indexed: 02/04/2023]
Abstract
The oncoprotein SET is frequently overexpressed in many types of tumors and contributes to malignant initiation and progression through multiple mechanisms, including the hijacking of the tumor suppressors p53 and PP2A. Targeting aberrant SET represents a promising strategy for cancer intervention. However, the mechanism by which endogenous SET is regulated in cancer cells remains largely unknown. Here, we identified the tumor suppressor p53 as a key regulator that transcriptionally repressed the expression of SET in both normal and cancer cells. In addition, p53 stimulated PP2A phosphatase activity via p53-mediated transcriptional repression of SET, whereby SET-mediated inhibition of PP2A was alleviated. Moreover, targeting the interaction between SET and PP2A catalytic subunit (PP2Ac) with FTY720 enhanced stress-induced p53 activation via PP2A-mediated dephosphorylation of p53 on threonine 55 (Thr55). Therefore, our findings uncovered a previously unknown p53-SET-PP2A regulatory feedback loop. To functionally potentiate this feedback loop, we designed a combined therapeutic strategy by simultaneously administrating a p53 activator and SET antagonist in cancer cells and observed a dramatic synergistic effect on tumor suppression. Our study reveals mechanistic insight into the regulation of the oncoprotein SET and raises a potential strategy for cancer therapy by stimulating the p53-SET-PP2A feedback loop.
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24
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Cheng C, Cai Y, Liu X, Wu Y, Cheng Q, Wu Y, Wu Z. KHSRP modulated cell proliferation and cell cycle via regulating PPP2CA and p27 expression in Wilms tumor. Cell Signal 2022; 100:110447. [PMID: 36029941 DOI: 10.1016/j.cellsig.2022.110447] [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: 01/04/2022] [Revised: 07/26/2022] [Accepted: 08/17/2022] [Indexed: 11/15/2022]
Abstract
Wilms tumor (WT) is the most common renal malignancy in children, and the survival rate of high-risk WT patients was still low despite multimodality therapy. KHSRP, an RNA-binding protein, has been proved to be relative to tumor progression in different kinds of malignancies, but the function of KHSRP in WT remained unclear. Here, our study aimed to explore and clarify the function of KHSRP in WT cells and its molecular mechanism. Thus, our results showed that KHSRP was highly expressed in WT tumor tissues compared to normal kidney tissues and correlated with poor prognosis in WT patients. Downregulation of KHSRP using siRNAs in WT cell line SK-NEP-1 and Wit49 resulted in inhibition of cell proliferation and cell cycle arrest via stabilizing and upregulating p27 protein. Furthermore, mechanistic analyses revealed that KHSRP bound to 3'UTR of PPP2CA mRNA and modulating its mRNA stability, resulting in regulation of the phosphorylation level and protein stability of p27 in WT cell lines. In conclusion, our results demonstrated that KHSRP played an important role in WT and modulated cell proliferation and cell cycle via regulating the expression of PPP2CA and p27.
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Affiliation(s)
- Cheng Cheng
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 200092 Shanghai, China; Division of Pediatric Oncology, Shanghai Institute of Pediatric Research, 200092 Shanghai, China
| | - Yuanxia Cai
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 200092 Shanghai, China; Division of Pediatric Oncology, Shanghai Institute of Pediatric Research, 200092 Shanghai, China
| | - Xiaowei Liu
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 200092 Shanghai, China; Division of Pediatric Oncology, Shanghai Institute of Pediatric Research, 200092 Shanghai, China
| | - Yangkun Wu
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 200092 Shanghai, China; Division of Pediatric Oncology, Shanghai Institute of Pediatric Research, 200092 Shanghai, China
| | - Qianqian Cheng
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 200092 Shanghai, China; Division of Pediatric Oncology, Shanghai Institute of Pediatric Research, 200092 Shanghai, China
| | - Yeming Wu
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 200092 Shanghai, China; Division of Pediatric Oncology, Shanghai Institute of Pediatric Research, 200092 Shanghai, China; Department of Pediatric Surgery, Hangzhou Children's Hospital, Hangzhou, Hangzhou 310010, China.
| | - Zhixiang Wu
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 200092 Shanghai, China; Division of Pediatric Oncology, Shanghai Institute of Pediatric Research, 200092 Shanghai, China; Department of Pediatric Surgery, Children's Hospital of Soochow University, 215003 Suzhou, China.
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25
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Teng M, Young DW, Tan Z. The Pursuit of Enzyme Activation: A Snapshot of the Gold Rush. J Med Chem 2022; 65:14289-14304. [PMID: 36265019 DOI: 10.1021/acs.jmedchem.2c01291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A range of enzymes drive human physiology, and their activities are tightly regulated through numerous signaling pathways. Depending on the context, these pathways may activate or inhibit an enzyme as a way to ensure proper execution of cellular functions. From a drug discovery and development perspective, pharmacological inhibition of enzymes has been a focus of interest, as many diseases are associated with the upregulation of enzyme function. On the other hand, however, pharmacological activation of enzymes such as kinases and phosphatases has been of increasing interest. In this review, we discuss seven case studies that highlight pharmacological activation strategy, describe the binding modes and pharmacology of the activators, and comment on how this on-demand activation strategy complements the commonly pursued inhibition strategy, thus jointly enabling bidirectional modulation of specific target of interest. Going forward, we expect activators to play important roles as chemical probes and drug leads.
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Affiliation(s)
- Mingxing Teng
- Department of Pathology & Immunology, and Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas 77030, United States
| | - Damian W Young
- Department of Pathology & Immunology, and Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas 77030, United States
| | - Zhi Tan
- Department of Pathology & Immunology, and Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas 77030, United States
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26
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Archambault V, Li J, Emond-Fraser V, Larouche M. Dephosphorylation in nuclear reassembly after mitosis. Front Cell Dev Biol 2022; 10:1012768. [PMID: 36268509 PMCID: PMC9576876 DOI: 10.3389/fcell.2022.1012768] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 08/31/2022] [Indexed: 11/13/2022] Open
Abstract
In most animal cell types, the interphase nucleus is largely disassembled during mitotic entry. The nuclear envelope breaks down and chromosomes are compacted into separated masses. Chromatin organization is also mostly lost and kinetochores assemble on centromeres. Mitotic protein kinases play several roles in inducing these transformations by phosphorylating multiple effector proteins. In many of these events, the mechanistic consequences of phosphorylation have been characterized. In comparison, how the nucleus reassembles at the end of mitosis is less well understood in mechanistic terms. In recent years, much progress has been made in deciphering how dephosphorylation of several effector proteins promotes nuclear envelope reassembly, chromosome decondensation, kinetochore disassembly and interphase chromatin organization. The precise roles of protein phosphatases in this process, in particular of the PP1 and PP2A groups, are emerging. Moreover, how these enzymes are temporally and spatially regulated to ensure that nuclear reassembly progresses in a coordinated manner has been partly uncovered. This review provides a global view of nuclear reassembly with a focus on the roles of dephosphorylation events. It also identifies important open questions and proposes hypotheses.
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Affiliation(s)
- Vincent Archambault
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC, Canada
- *Correspondence: Vincent Archambault,
| | - Jingjing Li
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC, Canada
| | - Virginie Emond-Fraser
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC, Canada
| | - Myreille Larouche
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
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27
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Kokot T, Köhn M. Emerging insights into serine/threonine-specific phosphoprotein phosphatase function and selectivity. J Cell Sci 2022; 135:277104. [DOI: 10.1242/jcs.259618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
ABSTRACT
Protein phosphorylation on serine and threonine residues is a widely distributed post-translational modification on proteins that acts to regulate their function. Phosphoprotein phosphatases (PPPs) contribute significantly to a plethora of cellular functions through the accurate dephosphorylation of phosphorylated residues. Most PPPs accomplish their purpose through the formation of complex holoenzymes composed of a catalytic subunit with various regulatory subunits. PPP holoenzymes then bind and dephosphorylate substrates in a highly specific manner. Despite the high prevalence of PPPs and their important role for cellular function, their mechanisms of action in the cell are still not well understood. Nevertheless, substantial experimental advancements in (phospho-)proteomics, structural and computational biology have contributed significantly to a better understanding of PPP biology in recent years. This Review focuses on recent approaches and provides an overview of substantial new insights into the complex mechanism of PPP holoenzyme regulation and substrate selectivity.
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Affiliation(s)
- Thomas Kokot
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg 1 , Freiburg 79104 , Germany
- University of Freiburg, 2 Faculty of Biology , Freiburg 79104 , Germany
| | - Maja Köhn
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg 1 , Freiburg 79104 , Germany
- University of Freiburg, 2 Faculty of Biology , Freiburg 79104 , Germany
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28
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Schuhmacher D, Sontag JM, Sontag E. A Novel Role of PP2A Methylation in the Regulation of Tight Junction Assembly and Integrity. Front Cell Dev Biol 2022; 10:911279. [PMID: 35912112 PMCID: PMC9326217 DOI: 10.3389/fcell.2022.911279] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 06/21/2022] [Indexed: 12/04/2022] Open
Abstract
Tight junctions (TJs) are multiprotein complexes essential for cell polarity and the barrier function of epithelia. The major signaling molecule, protein serine/threonine phosphatase 2A (PP2A), interacts with the TJ and modulates the phosphorylation state of TJ proteins. An important PP2A regulatory mechanism involves leucine carboxyl methyltransferase-1 (LCMT1)-dependent methylation and protein phosphatase methylesterase-1 (PME1)-mediated demethylation of its catalytic subunit on Leu309. Here, using MDCK cells, we show that overexpression of LCMT1, which enhances cellular PP2A methylation, inhibits TJ formation, induces TJ ruffling, and decreases TJ barrier function. Conversely, overexpression of PME1 accelerates TJ assembly and enhances TJ barrier function. PME1-dependent PP2A demethylation increases during early Ca2+-dependent junctional assembly. Inhibition of endogenous PME1 delays the initial Ca2+-mediated redistribution of TJ proteins to cell-cell contacts and affects TJ morphology and barrier function. Manipulating one-carbon metabolism modulates TJ assembly, at least in part by affecting PP2A methylation state. The integrity of PP2A methylation is critical for proper targeting of PP2A to the TJ. It is necessary for PP2A complex formation with the TJ proteins, occludin and ZO-1, and proteins of the PAR complex, Par3 and atypical protein kinase C ζ (aPKCζ), which play a key role in development of cell polarity. Expression of a methylation incompetent PP2A mutant induces defects in TJ assembly and barrier function. aPKCζ-mediated Par3 phosphorylation is also required for targeting of the PP2A ABαC holoenzyme to the TJ. Our findings provide the first evidence for a role of LCMT1, PME1 and PP2A methylation/demethylation processes in modulating TJ assembly and functional integrity. They also position PP2A at the interface of one-carbon metabolism and the regulation of key TJ and polarity proteins that become deregulated in many human diseases.
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29
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Pan J, Zhou L, Zhang C, Xu Q, Sun Y. Targeting protein phosphatases for the treatment of inflammation-related diseases: From signaling to therapy. Signal Transduct Target Ther 2022; 7:177. [PMID: 35665742 PMCID: PMC9166240 DOI: 10.1038/s41392-022-01038-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/28/2022] [Accepted: 05/25/2022] [Indexed: 11/09/2022] Open
Abstract
Inflammation is the common pathological basis of autoimmune diseases, metabolic diseases, malignant tumors, and other major chronic diseases. Inflammation plays an important role in tissue homeostasis. On one hand, inflammation can sense changes in the tissue environment, induce imbalance of tissue homeostasis, and cause tissue damage. On the other hand, inflammation can also initiate tissue damage repair and maintain normal tissue function by resolving injury and restoring homeostasis. These opposing functions emphasize the significance of accurate regulation of inflammatory homeostasis to ameliorate inflammation-related diseases. Potential mechanisms involve protein phosphorylation modifications by kinases and phosphatases, which have a crucial role in inflammatory homeostasis. The mechanisms by which many kinases resolve inflammation have been well reviewed, whereas a systematic summary of the functions of protein phosphatases in regulating inflammatory homeostasis is lacking. The molecular knowledge of protein phosphatases, and especially the unique biochemical traits of each family member, will be of critical importance for developing drugs that target phosphatases. Here, we provide a comprehensive summary of the structure, the "double-edged sword" function, and the extensive signaling pathways of all protein phosphatases in inflammation-related diseases, as well as their potential inhibitors or activators that can be used in therapeutic interventions in preclinical or clinical trials. We provide an integrated perspective on the current understanding of all the protein phosphatases associated with inflammation-related diseases, with the aim of facilitating the development of drugs that target protein phosphatases for the treatment of inflammation-related diseases.
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Affiliation(s)
- Jie Pan
- State Key Laboratory of Pharmaceutical Biotechnology, Chemistry and Biomedicine Innovation Center (ChemBIC), Department of Biotechnology and Pharmaceutical Sciences, School of Life Science, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China
| | - Lisha Zhou
- State Key Laboratory of Pharmaceutical Biotechnology, Chemistry and Biomedicine Innovation Center (ChemBIC), Department of Biotechnology and Pharmaceutical Sciences, School of Life Science, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China
| | - Chenyang Zhang
- State Key Laboratory of Pharmaceutical Biotechnology, Chemistry and Biomedicine Innovation Center (ChemBIC), Department of Biotechnology and Pharmaceutical Sciences, School of Life Science, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China
| | - Qiang Xu
- State Key Laboratory of Pharmaceutical Biotechnology, Chemistry and Biomedicine Innovation Center (ChemBIC), Department of Biotechnology and Pharmaceutical Sciences, School of Life Science, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, 209 Tongshan Road, Xuzhou, 221004, Jiangsu, China
| | - Yang Sun
- State Key Laboratory of Pharmaceutical Biotechnology, Chemistry and Biomedicine Innovation Center (ChemBIC), Department of Biotechnology and Pharmaceutical Sciences, School of Life Science, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China.
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, 209 Tongshan Road, Xuzhou, 221004, Jiangsu, China.
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30
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Manoharan GB, Okutachi S, Abankwa D. Potential of phenothiazines to synergistically block calmodulin and reactivate PP2A in cancer cells. PLoS One 2022; 17:e0268635. [PMID: 35617282 PMCID: PMC9135253 DOI: 10.1371/journal.pone.0268635] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 05/04/2022] [Indexed: 11/19/2022] Open
Abstract
Phenothiazines (PTZ) were developed as inhibitors of monoamine neurotransmitter receptors, notably dopamine receptors. Because of this activity they have been used for decades as antipsychotic drugs. In addition, they possess significant anti-cancer properties and several attempts for their repurposing were made. However, their incompletely understood polypharmacology is challenging. Here we examined the potential of the PTZ fluphenazine (Flu) and its mustard derivative (Flu-M) to synergistically act on two cancer associated targets, calmodulin (CaM) and the tumor suppressor protein phosphatase 2A (PP2A). Both proteins are known to modulate the Ras- and MAPK-pathway, cell viability and features of cancer cell stemness. Consistently, we show that the combination of a CaM inhibitor and the PP2A activator DT-061 synergistically inhibited the 3D-spheroid formation of MDA-MB-231 (K-Ras-G13D), NCI-H358 (K-Ras-G12C) and A375 (B-raf-V600E) cancer cells, and increased apoptosis in MDA-MB-231. We reasoned that these activities remain combined in PTZ, which were the starting point for PP2A activator development, while several PTZ are known CaM inhibitors. We show that both Flu and Flu-M retained CaM inhibitory activity in vitro and in cells, with a higher potency of the mustard derivative in cells. In line with the CaM dependence of Ras plasma membrane organization, the mustard derivative potently reduced the functional membrane organization of oncogenic Ras, while DT-061 had a negligible effect. Like DT-061, both PTZ potently decreased c-MYC levels, a hallmark of PP2A activation. Benchmarking against the KRAS-G12C specific inhibitor AMG-510 in MIA PaCa-2 cells revealed a higher potency of Flu-M than combinations of DT-061 and a CaM inhibitor on MAPK-output and a strong effect on cell proliferation. While our study is limited, our results suggest that improved PTZ derivatives that retain both, their CaM inhibitory and PP2A activating properties, but have lost their neurological side-effects, may be interesting to pursue further as anti-cancer agents.
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Affiliation(s)
- Ganesh Babu Manoharan
- Cancer Cell Biology and Drug Discovery Group, Department of Life Sciences and Medicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Sunday Okutachi
- Cancer Cell Biology and Drug Discovery Group, Department of Life Sciences and Medicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Daniel Abankwa
- Cancer Cell Biology and Drug Discovery Group, Department of Life Sciences and Medicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
- * E-mail:
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Mei C, Sun ZE, Tan LM, Gong JP, Li X, Liu ZQ. eIF3a-PPP2R5A-mediated ATM/ATR dephosphorylation is essential for irinotecan-induced DNA damage response. Cell Prolif 2022; 55:e13208. [PMID: 35187743 PMCID: PMC9055905 DOI: 10.1111/cpr.13208] [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: 12/14/2021] [Revised: 02/03/2022] [Accepted: 02/08/2022] [Indexed: 12/24/2022] Open
Abstract
Objectives The individual differences and pervasive resistance seriously hinder the optimization of irinotecan‐based therapeutic effectiveness. Eukaryotic translation initiation factor 3a (eIF3a) plays a key role in tumour occurrence, prognosis and therapeutic response. This study focused on the role of eIF3a in irinotecan‐induced DNA damage response. Materials and Methods The cck8 cell viability and clone survival analyses were used to test the regulatory role of eIF3a on irinotecan sensitivity in HT29 and CACO2 cell lines in vitro. This regulatory role was also verified in vivo by conducting subcutaneous xenograft model. Irinotecan‐induced DNA damage, cell cycle arrest and apoptosis were tested by flow cytometry analysis, TUNEL staining, western blot and comet assays. The immunofluorescence, co‐IP, luciferase reporter assay, RIP and flow cytometric analyses were carried out to investigate the underline mechanism. Results We demonstrated that eIF3a continuously activates ATM/ATR signal by translationally inhibiting PPP2R5A, a phosphatase that directly dephosphorylates and inactivates ATM/ATR after DNA repair complete. Suppression of PPP2R5A resulted in chronic ATM/ATR phosphorylation and activation, impairing DNA repair and enhancing irinotecan sensitivity. Conclusions Our study suggested eIF3a with a high potential to influence phenotypic functions, which may contribute substantially to the early identification of susceptible individuals and the provision of personalized medication to irinotecan‐treated patients.
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Affiliation(s)
- Chao Mei
- Department of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacology, Engineering Research Center for Applied Technology of Pharmacogenomics of Ministry of Education, Central South University, Changsha, China
| | - Ze-En Sun
- Department of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacology, Engineering Research Center for Applied Technology of Pharmacogenomics of Ministry of Education, Central South University, Changsha, China
| | - Li-Ming Tan
- Department of Pharmacy, The Second People's Hospital of Huaihua City, Huaihua, China
| | - Jian-Ping Gong
- Department of Pharmacy, The Second People's Hospital of Huaihua City, Huaihua, China
| | - Xi Li
- Department of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacology, Engineering Research Center for Applied Technology of Pharmacogenomics of Ministry of Education, Central South University, Changsha, China
| | - Zhao-Qian Liu
- Department of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacology, Engineering Research Center for Applied Technology of Pharmacogenomics of Ministry of Education, Central South University, Changsha, China
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Wang Y, Huang Q, Huang X, Zhao H, Guan B, Ban K, Zhu X, Ma Z, Tang Y, Su Z, Nong Q. Genetic Variant of PP2A Subunit Gene Confers an Increased Risk of Primary Liver Cancer in Chinese. Pharmgenomics Pers Med 2021; 14:1565-1574. [PMID: 34898995 PMCID: PMC8654694 DOI: 10.2147/pgpm.s335555] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 11/10/2021] [Indexed: 12/14/2022] Open
Abstract
Background Protein phosphatase 2A (PP2A, a serine/threonine phosphatase) is frequently inactivated in many types of cancer, including primary liver cancer (PLC). Genetic variations in PP2A subunits have been reported to be associated with the risk of many types of cancer but rarely in PLC. This study aims to assess the association between functional polymorphisms of PP2A subunit genes and the risk of PLC in Chinese. Methods In a case-control study with a total of 541 PLC patients and 547 controls in Guangxi province of Southern China, we genotyped six putatively functional polymorphisms (rs10421191G>A, rs11453459del>insG, rs1560092T>G, rs7840855C>T, rs1255722G>A and rs10151527A>C) of three PP2A subunit genes (PPP2R1A, PPP2R2A and PPP2R5E) using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry platform. Results The rs11453459insG variant genotypes (ins/ins+del/ins) of PPP2R1A were found to be significantly associated with an increased risk of PLC compared with the del/del genotype (adjusted OR = 1.290, 95% CI = 1.009–1.650), and the number of insert G allele worked in a dose-dependent manner (Ptrend= 0.007). The stratified analysis showed that the effects of rs11453459insG variant genotypes were more evident in the subgroup who drink pond-ditch water (adjusted OR = 3.051, 95% CI = 1.264–7.364) than those never drink (P = 0.041). The carriers of rs11453459 del/ins genotype had a significantly lower level of PPP2R1A mRNA expression in liver cancer tissues than those of the del/del genotype (P = 0.021). Furthermore, we used microcystin-LR, a carcinogen presents in the pond-ditch water, to treat human peripheral blood mononuclear cells and found that the cells from carriers of rs11453459insG variant genotypes induced more DNA oxidative damages than those from the del/del genotype carriers (P < 0.001). Conclusion These findings suggest that the PPP2R1A rs11453459del>insG polymorphism is associated with an increased risk of PLC, especially for persons with a history of drinking pond-ditch water. This insertion/deletion polymorphism may be a susceptible biomarker for PLC in Chinese.
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Affiliation(s)
- Youxin Wang
- Department of Environmental Health, School of Public Health, Guangxi Medical University, Nanning, 530021, People's Republic of China
| | - Qiuyue Huang
- Department of Environmental Health, School of Public Health, Guangxi Medical University, Nanning, 530021, People's Republic of China
| | - Xinglei Huang
- Department of Environmental Health, School of Public Health, Guangxi Medical University, Nanning, 530021, People's Republic of China
| | - Huiliu Zhao
- Department of Clinical Laboratory, The Affiliated Tumor Hospital of Guangxi Medical University, Nanning, 530021, People's Republic of China
| | - Bin Guan
- Department of Environmental Health, School of Public Health, Guangxi Medical University, Nanning, 530021, People's Republic of China
| | - Kechen Ban
- Department of Pathology, The University of Texas M. D. Anderson Cancer Center, Houston, TX, 77030, USA
| | - Xuefeng Zhu
- Department of Environmental Health, School of Public Health, Guangxi Medical University, Nanning, 530021, People's Republic of China
| | - Zhixing Ma
- Department of Environmental Health, School of Public Health, Guangxi Medical University, Nanning, 530021, People's Republic of China
| | - Yanmei Tang
- Department of Environmental Health, School of Public Health, Guangxi Medical University, Nanning, 530021, People's Republic of China
| | - Zhaohui Su
- Department of Environmental Health, School of Public Health, Guangxi Medical University, Nanning, 530021, People's Republic of China
| | - Qingqing Nong
- Department of Environmental Health, School of Public Health, Guangxi Medical University, Nanning, 530021, People's Republic of China
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33
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Sergienko NM, Donner DG, Delbridge LMD, McMullen JR, Weeks KL. Protein phosphatase 2A in the healthy and failing heart: New insights and therapeutic opportunities. Cell Signal 2021; 91:110213. [PMID: 34902541 DOI: 10.1016/j.cellsig.2021.110213] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 12/02/2021] [Accepted: 12/07/2021] [Indexed: 02/06/2023]
Abstract
Protein phosphatases have emerged as critical regulators of phosphoprotein homeostasis in settings of health and disease. Protein phosphatase 2A (PP2A) encompasses a large subfamily of enzymes that remove phosphate groups from serine/threonine residues within phosphoproteins. The heterogeneity in PP2A structure, which arises from the grouping of different catalytic, scaffolding and regulatory subunit isoforms, creates distinct populations of catalytically active enzymes (i.e. holoenzymes) that localise to different parts of the cell. This structural complexity, combined with other regulatory mechanisms, such as interaction of PP2A heterotrimers with accessory proteins and post-translational modification of the catalytic and/or regulatory subunits, enables PP2A holoenzymes to target phosphoprotein substrates in a highly specific manner. In this review, we summarise the roles of PP2A in cardiac physiology and disease. PP2A modulates numerous processes that are vital for heart function including calcium handling, contractility, β-adrenergic signalling, metabolism and transcription. Dysregulation of PP2A has been observed in human cardiac disease settings, including heart failure and atrial fibrillation. Efforts are underway, particularly in the cancer field, to develop therapeutics targeting PP2A activity. The development of small molecule activators of PP2A (SMAPs) and other compounds that selectively target specific PP2A holoenzymes (e.g. PP2A/B56α and PP2A/B56ε) will improve understanding of the function of different PP2A species in the heart, and may lead to the development of therapeutics for normalising aberrant protein phosphorylation in settings of cardiac remodelling and dysfunction.
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Affiliation(s)
- Nicola M Sergienko
- Baker Heart and Diabetes Institute, Melbourne VIC 3004, Australia; Central Clinical School, Monash University, Clayton VIC 3800, Australia
| | - Daniel G Donner
- Baker Heart and Diabetes Institute, Melbourne VIC 3004, Australia; Baker Department of Cardiometabolic Health, The University of Melbourne, Parkville VIC 3010, Australia
| | - Lea M D Delbridge
- Department of Anatomy and Physiology, The University of Melbourne, Parkville VIC 3010, Australia
| | - Julie R McMullen
- Baker Heart and Diabetes Institute, Melbourne VIC 3004, Australia; Baker Department of Cardiometabolic Health, The University of Melbourne, Parkville VIC 3010, Australia; Department of Physiology and Department of Medicine Alfred Hospital, Monash University, Clayton VIC 3800, Australia; Department of Physiology, Anatomy and Microbiology, La Trobe University, Bundoora VIC 3086, Australia; Department of Diabetes, Central Clinical School, Monash University, Clayton VIC 3800, Australia.
| | - Kate L Weeks
- Baker Heart and Diabetes Institute, Melbourne VIC 3004, Australia; Department of Anatomy and Physiology, The University of Melbourne, Parkville VIC 3010, Australia; Baker Department of Cardiometabolic Health, The University of Melbourne, Parkville VIC 3010, Australia; Department of Diabetes, Central Clinical School, Monash University, Clayton VIC 3800, Australia.
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Xiaoli L, Fengbin H, Shihui H, Xi N, Sheng L, Zhou W, Xueqin R, Jiafu W. Detection of genomic structure variants associated with wrinkled skin in Xiang pig by next generation sequencing. Aging (Albany NY) 2021; 13:24710-24739. [PMID: 34837693 PMCID: PMC8660620 DOI: 10.18632/aging.203711] [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: 12/30/2020] [Accepted: 08/02/2021] [Indexed: 11/25/2022]
Abstract
Wrinkling is prominent manifestation of aging skin. A mutant phenotype characterized by systemic wrinkles and thickened skin was discovered in Xiang pig populations with incidence about 1-3%. The feature in histological structure was epidermal hyperplasia and thickening, collagen fibers disorder. To uncover genetic mechanisms for the mutant phenotype of Xiang pigs with systemic wrinkle (WXP), a genome-wide of structural variations (SVs) in WXP was described by next generation resequencing, taking Xiang pigs (XP) and European pigs (EUP) as compares. Total of 32,308 SVs were detected from three pig groups and 965 SVs were identified specifically from WXP, involving 481 protein-coding genes. These genes were mainly enriched in nuclear structure, ECM components and immunomodulatory pathways. According to gene function and enrichment analysis, we found that 65 candidate SVs in 59 protein genes were probably related with the systemic wrinkle of WXP. Of these, several genes are reported to be associate with aging, such as EIF4G2, NOLC1, XYLT1, FUT8, MDM2 and so on. The insertion/deletion and duplication variations of SVs in these genes resulted in the loss of stop-codon or frameshift mutation, and aberrant alternative splicing of transcripts. These genes are involved in cell lamin filament, intermediate filament cytoskeleton, supramolecular complex, cell differentiation and regulation of macromolecule metabolic process etc. Our study suggested that the loss of function or aberrant expression of these genes lead to structural disorder of nuclear and the extracellular matrix (ECM) in skin cells, which probably was the genetic mechanisms for the mutant phenotype of systemic skin wrinkle of Xiang pig.
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Affiliation(s)
- Liu Xiaoli
- Institute of Agro-Bioengineering, Key Laboratory of Plant Resource Conservative and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Science and College of Animal Science, Guizhou University, Guiyang 550025, China
| | - Hu Fengbin
- Institute of Agro-Bioengineering, Key Laboratory of Plant Resource Conservative and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Science and College of Animal Science, Guizhou University, Guiyang 550025, China
| | - Huang Shihui
- Institute of Agro-Bioengineering, Key Laboratory of Plant Resource Conservative and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Science and College of Animal Science, Guizhou University, Guiyang 550025, China
| | - Niu Xi
- Institute of Agro-Bioengineering, Key Laboratory of Plant Resource Conservative and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Science and College of Animal Science, Guizhou University, Guiyang 550025, China
| | - Li Sheng
- Institute of Agro-Bioengineering, Key Laboratory of Plant Resource Conservative and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Science and College of Animal Science, Guizhou University, Guiyang 550025, China
| | - Wang Zhou
- Institute of Agro-Bioengineering, Key Laboratory of Plant Resource Conservative and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Science and College of Animal Science, Guizhou University, Guiyang 550025, China
| | - Ran Xueqin
- Institute of Agro-Bioengineering, Key Laboratory of Plant Resource Conservative and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Science and College of Animal Science, Guizhou University, Guiyang 550025, China
| | - Wang Jiafu
- Institute of Agro-Bioengineering, Key Laboratory of Plant Resource Conservative and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Science and College of Animal Science, Guizhou University, Guiyang 550025, China
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Fowle H, Zhao Z, Xu Q, Wasserman JS, Wang X, Adeyemi M, Feiser F, Kurimchak AN, Atar D, McEwan BC, Kettenbach AN, Page R, Peti W, Dunbrack RL, Graña X. PP2A/B55α substrate recruitment as defined by the retinoblastoma-related protein p107. eLife 2021; 10:63181. [PMID: 34661528 PMCID: PMC8575462 DOI: 10.7554/elife.63181] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 10/17/2021] [Indexed: 12/23/2022] Open
Abstract
Protein phosphorylation is a reversible post-translation modification essential in cell signaling. This study addresses a long-standing question as to how the most abundant serine/threonine protein phosphatase 2 (PP2A) holoenzyme, PP2A/B55α, specifically recognizes substrates and presents them to the enzyme active site. Here, we show how the PP2A regulatory subunit B55α recruits p107, a pRB-related tumor suppressor and B55α substrate. Using molecular and cellular approaches, we identified a conserved region 1 (R1, residues 615–626) encompassing the strongest p107 binding site. This enabled us to identify an ‘HxRVxxV619-625’ short linear motif (SLiM) in p107 as necessary for B55α binding and dephosphorylation of the proximal pSer-615 in vitro and in cells. Numerous B55α/PP2A substrates, including TAU, contain a related SLiM C-terminal from a proximal phosphosite, ‘p[ST]-P-x(4,10)-[RK]-V-x-x-[VI]-R.’ Mutation of conserved SLiM residues in TAU dramatically inhibits dephosphorylation by PP2A/B55α, validating its generality. A data-guided computational model details the interaction of residues from the conserved p107 SLiM, the B55α groove, and phosphosite presentation. Altogether, these data provide key insights into PP2A/B55α’s mechanisms of substrate recruitment and active site engagement, and also facilitate identification and validation of new substrates, a key step towards understanding PP2A/B55α’s role in multiple cellular processes.
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Affiliation(s)
- Holly Fowle
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, United States
| | - Ziran Zhao
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, United States
| | - Qifang Xu
- Fels Institute for Cancer Research and Molecular Biology, Temple University Lewis Katz School of Medicine, Philadelphia, United States
| | - Jason S Wasserman
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, United States
| | - Xinru Wang
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, United States
| | - Mary Adeyemi
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, United States
| | - Felicity Feiser
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, United States
| | - Alison N Kurimchak
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, United States
| | - Diba Atar
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, United States
| | - Brennan C McEwan
- Department of Biochemistry and Cell Biology, Hitchcock Medical Center at Dartmouth, Lebanon, United States
| | - Arminja N Kettenbach
- Department of Biochemistry and Cell Biology, Hitchcock Medical Center at Dartmouth, Lebanon, United States
| | - Rebecca Page
- Department Cell Biology, UConn Health, Farmington, United States
| | - Wolfgang Peti
- Department Molecular Biology and Biophysics, UConn Health, Farmington, United States
| | - Roland L Dunbrack
- Fels Institute for Cancer Research and Molecular Biology, Temple University Lewis Katz School of Medicine, Philadelphia, United States
| | - Xavier Graña
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, United States
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36
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Inhibiting PP2Ac α Promotes the Malignant Phenotype of Gastric Cancer Cells through the ATM/METTL3 Axis. BIOMED RESEARCH INTERNATIONAL 2021; 2021:1015293. [PMID: 34485508 PMCID: PMC8410407 DOI: 10.1155/2021/1015293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 08/06/2021] [Indexed: 12/24/2022]
Abstract
This article is aimed at exploring the relationship between the phosphatase 2A catalytic subunit Cα (PP2Acα, encoded by PPP2CA) and methyltransferase-like 3 (METTL3) in the malignant progression of gastric cancer (GC). Through analyzing the bioinformatics database and clinical tissue immunohistochemistry results, we found that abnormal PP2Acα and METTL3 levels were closely related to the malignant progression of GC. To explore the internal connection between PP2Acα and METTL3 in the progression of GC, we carried out cellular and molecular experiments and finally proved that PP2Acα inhibition can upregulate METTL3 levels by activating ATM activity, thereby promoting the malignant progression of GC.
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37
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Weidle UH, Birzele F. Bladder Cancer-related microRNAs With In Vivo Efficacy in Preclinical Models. CANCER DIAGNOSIS & PROGNOSIS 2021; 1:245-263. [PMID: 35403137 PMCID: PMC8988954 DOI: 10.21873/cdp.10033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 06/15/2021] [Indexed: 06/14/2023]
Abstract
Progressive and metastatic bladder cancer remain difficult to treat. In this review, we critique seven up-regulated and 25 down-regulated microRNAs in order to identify new therapeutic entities and corresponding targets. These microRNAs were selected with respect to their efficacy in bladder cancer-related preclinical in vivo models. MicroRNAs and related targets interfering with chemoresistance, cell-cycle, signaling, apoptosis, autophagy, transcription factor modulation, epigenetic modification and metabolism are described. In addition, we highlight microRNAs targeting transmembrane receptors and secreted factors. We discuss druggability issues for the identified targets.
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Affiliation(s)
- Ulrich H Weidle
- Roche Pharma Research and Early Development, Roche Innovation Center Munich, Penzberg, Germany
| | - Fabian Birzele
- Roche Pharma Research and Early Development, Pharmaceutical Sciences,Roche Innovation Center Basel, Basel, Switzerland
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38
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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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Vainonen JP, Momeny M, Westermarck J. Druggable cancer phosphatases. Sci Transl Med 2021; 13:13/588/eabe2967. [PMID: 33827975 DOI: 10.1126/scitranslmed.abe2967] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 02/08/2021] [Indexed: 12/12/2022]
Abstract
The phosphorylation status of oncoproteins is regulated by both kinases and phosphatases. Kinase inhibitors are rarely sufficient for successful cancer treatment, and phosphatases have been considered undruggable targets for cancer drug development. However, innovative pharmacological approaches for targeting phosphatases have recently emerged. Here, we review progress in the therapeutic targeting of oncogenic Src homology region 2 domain-containing phosphatase-2 (SHP2) and tumor suppressor protein phosphatase 2A (PP2A) and select other druggable oncogenic and tumor suppressor phosphatases. We describe the modes of action for currently available small molecules that target phosphatases, their use in drug combinations, and advances in clinical development toward future cancer therapies.
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Affiliation(s)
- Julia P Vainonen
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Majid Momeny
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - 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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Rivas M, Johnston ME, Gulati R, Kumbaji M, Margues Aguiar TF, Timchenko L, Krepischi A, Shin S, Bondoc A, Tiao G, Geller J, Timchenko N. HDAC1-Dependent Repression of Markers of Hepatocytes and P21 Is Involved in Development of Pediatric Liver Cancer. Cell Mol Gastroenterol Hepatol 2021; 12:1669-1682. [PMID: 34245919 PMCID: PMC8536541 DOI: 10.1016/j.jcmgh.2021.06.026] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/29/2021] [Accepted: 06/30/2021] [Indexed: 02/08/2023]
Abstract
BACKGROUND & AIMS Epigenetic regulation of gene expression plays a critical role in the development of liver cancer; however, the molecular mechanisms of epigenetic-driven liver cancers are not well understood. The aims of this study were to examine molecular mechanisms that cause the dedifferentiation of hepatocytes into cancer cells in aggressive hepatoblastoma and test if the inhibition of these mechanisms inhibits tumor growth. METHODS We have analyzed CCAAT/Enhancer Binding Protein alpha (C/EBPα), Transcription factor Sp5, and histone deacetylase (HDAC)1 pathways from a large biobank of fresh hepatoblastoma (HBL) samples using high-pressure liquid chromatography-based examination of protein-protein complexes and have examined chromatin remodeling on the promoters of markers of hepatocytes and p21. The HDAC1 activity was inhibited in patient-derived xenograft models of HBL and in cultured hepatoblastoma cells and expression of HDAC1-dependent markers of hepatocytes was examined. RESULTS Analyses of a biobank showed that a significant portion of HBL patients have increased levels of an oncogenic de-phosphorylated-S190-C/EBPα, Sp5, and HDAC1 compared with amounts of these proteins in adjacent regions. We found that the oncogenic de-phosphorylated-S190-C/EBPα is created in aggressive HBL by protein phosphatase 2A, which is increased within the nucleus and dephosphorylates C/EBPα at Ser190. C/EBPα-HDAC1 and Sp5-HDAC1 complexes are abundant in hepatocytes, which dedifferentiate into cancer cells. Studies in HBL cells have shown that C/EBPα-HDAC1 and Sp5-HDAC1 complexes reduce markers of hepatocytes and p21 via repression of their promoters. Pharmacologic inhibition of C/EBPα-HDAC1 and Sp5-HDAC1 complexes by Suberoylanilide hydroxamic acid (SAHA) and small interfering RNA-mediated inhibition of HDAC1 increase expression of hepatocyte markers, p21, and inhibit proliferation of cancer cells. CONCLUSIONS HDAC1-mediated repression of markers of hepatocytes is an essential step for the development of HBL, providing background for generation of therapies for aggressive HBL by targeting HDAC1 activities.
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Affiliation(s)
- Maria Rivas
- Division of General and Thoracic Surgery, Cincinnati, Ohio,Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | - Michael E. Johnston
- Division of General and Thoracic Surgery, Cincinnati, Ohio,Department of Surgery, University of Cincinnati College of Medicine, University of Cincinnati, Cincinnati, Ohio
| | - Ruhi Gulati
- Division of General and Thoracic Surgery, Cincinnati, Ohio
| | | | | | | | - Ana Krepischi
- Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | - Soona Shin
- Division of General and Thoracic Surgery, Cincinnati, Ohio,Department of Surgery, University of Cincinnati College of Medicine, University of Cincinnati, Cincinnati, Ohio
| | | | - Gregory Tiao
- Division of General and Thoracic Surgery, Cincinnati, Ohio,Department of Surgery, University of Cincinnati College of Medicine, University of Cincinnati, Cincinnati, Ohio
| | - James Geller
- Department of Oncology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
| | - Nikolai Timchenko
- Division of General and Thoracic Surgery, Cincinnati, Ohio,Department of Surgery, University of Cincinnati College of Medicine, University of Cincinnati, Cincinnati, Ohio,Correspondence Address correspondence to: Nikolai Timchenko, PhD, Liver Tumor Program, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, Ohio 45229. fax: (513) 636-4200.
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Vervoort SJ, Welsh SA, Devlin JR, Barbieri E, Knight DA, Offley S, Bjelosevic S, Costacurta M, Todorovski I, Kearney CJ, Sandow JJ, Fan Z, Blyth B, McLeod V, Vissers JHA, Pavic K, Martin BP, Gregory G, Demosthenous E, Zethoven M, Kong IY, Hawkins ED, Hogg SJ, Kelly MJ, Newbold A, Simpson KJ, Kauko O, Harvey KF, Ohlmeyer M, Westermarck J, Gray N, Gardini A, Johnstone RW. The PP2A-Integrator-CDK9 axis fine-tunes transcription and can be targeted therapeutically in cancer. Cell 2021; 184:3143-3162.e32. [PMID: 34004147 PMCID: PMC8567840 DOI: 10.1016/j.cell.2021.04.022] [Citation(s) in RCA: 86] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 11/27/2020] [Accepted: 04/14/2021] [Indexed: 12/18/2022]
Abstract
Gene expression by RNA polymerase II (RNAPII) is tightly controlled by cyclin-dependent kinases (CDKs) at discrete checkpoints during the transcription cycle. The pausing checkpoint following transcription initiation is primarily controlled by CDK9. We discovered that CDK9-mediated, RNAPII-driven transcription is functionally opposed by a protein phosphatase 2A (PP2A) complex that is recruited to transcription sites by the Integrator complex subunit INTS6. PP2A dynamically antagonizes phosphorylation of key CDK9 substrates including DSIF and RNAPII-CTD. Loss of INTS6 results in resistance to tumor cell death mediated by CDK9 inhibition, decreased turnover of CDK9 phospho-substrates, and amplification of acute oncogenic transcriptional responses. Pharmacological PP2A activation synergizes with CDK9 inhibition to kill both leukemic and solid tumor cells, providing therapeutic benefit in vivo. These data demonstrate that fine control of gene expression relies on the balance between kinase and phosphatase activity throughout the transcription cycle, a process dysregulated in cancer that can be exploited therapeutically.
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Affiliation(s)
- Stephin J Vervoort
- Peter MacCallum Cancer Centre, Melbourne 3000, VIC, Australia; The Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville 3010, VIC, Australia.
| | - Sarah A Welsh
- The Wistar Institute, Philadelphia, PA 19104, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jennifer R Devlin
- Peter MacCallum Cancer Centre, Melbourne 3000, VIC, Australia; The Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville 3010, VIC, Australia
| | | | - Deborah A Knight
- Peter MacCallum Cancer Centre, Melbourne 3000, VIC, Australia; The Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Sarah Offley
- The Wistar Institute, Philadelphia, PA 19104, USA; Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Stefan Bjelosevic
- Peter MacCallum Cancer Centre, Melbourne 3000, VIC, Australia; The Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Matteo Costacurta
- Peter MacCallum Cancer Centre, Melbourne 3000, VIC, Australia; The Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Izabela Todorovski
- Peter MacCallum Cancer Centre, Melbourne 3000, VIC, Australia; The Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Conor J Kearney
- Peter MacCallum Cancer Centre, Melbourne 3000, VIC, Australia; The Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Jarrod J Sandow
- The Walter and Eliza Hall Institute, Parkville 3010, VIC, Australia; Department of Medical Biology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Zheng Fan
- Peter MacCallum Cancer Centre, Melbourne 3000, VIC, Australia; The Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Benjamin Blyth
- Peter MacCallum Cancer Centre, Melbourne 3000, VIC, Australia
| | - Victoria McLeod
- Peter MacCallum Cancer Centre, Melbourne 3000, VIC, Australia
| | - Joseph H A Vissers
- Peter MacCallum Cancer Centre, Melbourne 3000, VIC, Australia; The Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville 3010, VIC, Australia; Centre for Cancer Research and Department of Clinical Pathology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Karolina Pavic
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku FI-20014, Finland; Institute of Biomedicine, University of Turku, Turku FI-20014, Finland
| | - Ben P Martin
- Peter MacCallum Cancer Centre, Melbourne 3000, VIC, Australia; The Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Gareth Gregory
- Peter MacCallum Cancer Centre, Melbourne 3000, VIC, Australia; The Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville 3010, VIC, Australia; School of Clinical Sciences at Monash Health, Monash University, Clayton 3168, VIC, Australia
| | | | - Magnus Zethoven
- Peter MacCallum Cancer Centre, Melbourne 3000, VIC, Australia
| | - Isabella Y Kong
- The Walter and Eliza Hall Institute, Parkville 3010, VIC, Australia; Department of Medical Biology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Edwin D Hawkins
- The Walter and Eliza Hall Institute, Parkville 3010, VIC, Australia; Department of Medical Biology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Simon J Hogg
- Peter MacCallum Cancer Centre, Melbourne 3000, VIC, Australia; The Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Madison J Kelly
- Peter MacCallum Cancer Centre, Melbourne 3000, VIC, Australia; The Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Andrea Newbold
- Peter MacCallum Cancer Centre, Melbourne 3000, VIC, Australia; The Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville 3010, VIC, Australia
| | | | - Otto Kauko
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku FI-20014, Finland; Institute of Biomedicine, University of Turku, Turku FI-20014, Finland
| | - Kieran F Harvey
- Peter MacCallum Cancer Centre, Melbourne 3000, VIC, Australia; The Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville 3010, VIC, Australia; Department of Anatomy and Developmental Biology, and Biomedicine Discovery Institute, Monash University, Clayton 3168, VIC, Australia
| | - Michael Ohlmeyer
- Mount Sinai School of Medicine, New York, NY 10029, USA; Atux Iskay LLC, Plainsboro, NJ 08536, USA
| | - Jukka Westermarck
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku FI-20014, Finland; Institute of Biomedicine, University of Turku, Turku FI-20014, Finland
| | | | | | - Ricky W Johnstone
- Peter MacCallum Cancer Centre, Melbourne 3000, VIC, Australia; The Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville 3010, VIC, Australia.
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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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43
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Dzulko M, Pons M, Henke A, Schneider G, Krämer OH. The PP2A subunit PR130 is a key regulator of cell development and oncogenic transformation. Biochim Biophys Acta Rev Cancer 2020; 1874:188453. [PMID: 33068647 DOI: 10.1016/j.bbcan.2020.188453] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 10/10/2020] [Accepted: 10/11/2020] [Indexed: 12/25/2022]
Abstract
Protein phosphatase 2A (PP2A) is a major serine/threonine phosphatase. This enzyme is involved in a plethora of cellular processes, including apoptosis, autophagy, cell proliferation, and DNA repair. Remarkably, PP2A can act as a context-dependent tumor suppressor or promoter. Active PP2A complexes consist of structural (PP2A-A), regulatory (PP2A-B), and catalytic (PP2A-C) subunits. The regulatory subunits define the substrate specificity and the subcellular localization of the holoenzyme. Here we condense the increasing evidence that the PP2A B-type subunit PR130 is a critical regulator of cell identity and oncogenic transformation. We summarize knowledge on the biological functions of PR130 in normal and transformed cells, targets of the PP2A-PR130 complex, and how diverse extra- and intracellular stimuli control the expression and activity of PR130. We additionally review the impact of PP2A-PR130 on cardiac functions, neuronal processes, and anti-viral defense and how this might affect cancer development and therapy.
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Affiliation(s)
- Melanie Dzulko
- Department of Toxicology, University Medical Center, 55131 Mainz, Germany
| | - Miriam Pons
- Department of Toxicology, University Medical Center, 55131 Mainz, Germany
| | - Andreas Henke
- Section of Experimental Virology, Institute of Medical Microbiology, Jena University Hospital, Friedrich Schiller University, 07745 Jena, Germany
| | - Günter Schneider
- Klinik und Poliklinik für Innere Medizin II, Technical University of Munich, 81675 Munich, Germany
| | - Oliver H Krämer
- Department of Toxicology, University Medical Center, 55131 Mainz, Germany.
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44
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Lei X, Ma N, Du L, Liang Y, Zhang P, Han Y, Qu B. PP2A and tumor radiotherapy. Hereditas 2020; 157:36. [PMID: 32847617 PMCID: PMC7450598 DOI: 10.1186/s41065-020-00149-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 08/13/2020] [Indexed: 02/07/2023] Open
Abstract
Protein phosphatase 2A (PP2A) is a serine/threonine phosphatase that serves as a key regulator of cellular physiology in the context of apoptosis, mitosis, and DNA damage responses. Canonically, PP2A functions as a tumor suppressor gene. However, recent evidence suggests that inhibiting PP2A activity in tumor cells may represent a viable approach to enhancing tumor sensitivity to chemoradiotherapy as such inhibition can cause cells to enter a disordered mitotic state that renders them more susceptible to cell death. Indeed, there is evidence that inhibiting PP2A can slow tumor growth following radiotherapy in a range of cancer types including ovarian cancer, liver cancer, malignant glioma, pancreatic cancer, and nasopharyngeal carcinoma. In the present review, we discuss current understanding of the role of PP2A in tumor radiotherapy and the potential mechanisms whereby it may influence this process.
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Affiliation(s)
- Xiao Lei
- The First Medical Center of Chinese PLA General Hospital, Department of Radiation Oncology, Beijing, P. R. China
| | - Na Ma
- The First Medical Center of Chinese PLA General Hospital, Department of Radiation Oncology, Beijing, P. R. China
| | - Lehui Du
- The First Medical Center of Chinese PLA General Hospital, Department of Radiation Oncology, Beijing, P. R. China
| | - Yanjie Liang
- The First Medical Center of Chinese PLA General Hospital, Department of Radiation Oncology, Beijing, P. R. China
| | - Pei Zhang
- The First Medical Center of Chinese PLA General Hospital, Department of Radiation Oncology, Beijing, P. R. China
| | - Yanan Han
- The First Medical Center of Chinese PLA General Hospital, Department of Radiation Oncology, Beijing, P. R. China
| | - Baolin Qu
- The First Medical Center of Chinese PLA General Hospital, Department of Radiation Oncology, Beijing, P. R. China.
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45
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Pietropaolo V, Prezioso C, Moens U. Merkel Cell Polyomavirus and Merkel Cell Carcinoma. Cancers (Basel) 2020; 12:E1774. [PMID: 32635198 PMCID: PMC7407210 DOI: 10.3390/cancers12071774] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 06/26/2020] [Accepted: 06/28/2020] [Indexed: 12/12/2022] Open
Abstract
Viruses are the cause of approximately 15% of all human cancers. Both RNA and DNA human tumor viruses have been identified, with Merkel cell polyomavirus being the most recent one to be linked to cancer. This virus is associated with about 80% of Merkel cell carcinomas, a rare, but aggressive cutaneous malignancy. Despite its name, the cells of origin of this tumor may not be Merkel cells. This review provides an update on the structure and life cycle, cell tropism and epidemiology of the virus and its oncogenic properties. Putative strategies to prevent viral infection or treat virus-positive Merkel cell carcinoma patients are discussed.
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Affiliation(s)
- Valeria Pietropaolo
- Department of Public Health and Infectious Diseases, “Sapienza” University, 00185 Rome, Italy; (V.P.); (C.P.)
| | - Carla Prezioso
- Department of Public Health and Infectious Diseases, “Sapienza” University, 00185 Rome, Italy; (V.P.); (C.P.)
- IRCSS San Raffaele Pisana, Microbiology of Chronic Neuro-Degenerative Pathologies, 00166 Rome, Italy
| | - Ugo Moens
- Molecular Inflammation Research Group, Department of Medical Biology, Faculty of Health Sciences, University of Tromsø—The Arctic University of Norway, 9037 Tromsø, Norway
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46
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Zhao Z, Kurimchak A, Nikonova AS, Feiser F, Wasserman JS, Fowle H, Varughese T, Connors M, Johnson K, Makhov P, Lindskog C, Kolenko VM, Golemis EA, Duncan JS, Graña X. PPP2R2A prostate cancer haploinsufficiency is associated with worse prognosis and a high vulnerability to B55α/PP2A reconstitution that triggers centrosome destabilization. Oncogenesis 2019; 8:72. [PMID: 31822657 PMCID: PMC6904742 DOI: 10.1038/s41389-019-0180-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 11/18/2019] [Accepted: 11/20/2019] [Indexed: 12/12/2022] Open
Abstract
The PPP2R2A gene encodes the B55α regulatory subunit of PP2A. Here, we report that PPP2R2A is hemizygously lost in ~42% of prostate adenocarcinomas, correlating with reduced expression, poorer prognosis, and an increased incidence of hemizygous loss (>75%) in metastatic disease. Of note, PPP2R2A homozygous loss is less common (5%) and not increased at later tumor stages. Reduced expression of B55α is also seen in prostate tumor tissue and cell lines. Consistent with the possibility that complete loss of PPP2R2A is detrimental in prostate tumors, PPP2R2A deletion in cells with reduced but present B55α reduces cell proliferation by slowing progression through the cell cycle. Remarkably, B55α-low cells also appear addicted to lower B55α expression, as even moderate increases in B55α expression are toxic. Reconstitution of B55α expression in prostate cancer (PCa) cell lines with low B55α expression reduces proliferation, inhibits transformation and blocks xenograft tumorigenicity. Mechanistically, we show B55α reconstitution reduces phosphorylation of proteins essential for centrosomal maintenance, and induces centrosome collapse and chromosome segregation failure; a first reported link between B55α/PP2A and the vertebrate centrosome. These effects are dependent on a prolonged metaphase/anaphase checkpoint and are lethal to PCa cells addicted to low levels of B55α. Thus, we propose the reduction in B55α levels associated with hemizygous loss is necessary for centrosomal integrity in PCa cells, leading to selective lethality of B55α reconstitution. Such a vulnerability could be targeted therapeutically in the large pool of patients with hemizygous PPP2R2A deletions, using pharmacologic approaches that enhance PP2A/B55α activity.
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Affiliation(s)
- Ziran Zhao
- Fels Institute for Cancer Research and Molecular Biology, Temple University Lewis Katz School of Medicine, Philadelphia, PA, 19140, USA
| | - Alison Kurimchak
- Fels Institute for Cancer Research and Molecular Biology, Temple University Lewis Katz School of Medicine, Philadelphia, PA, 19140, USA.,Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | | | - Felicity Feiser
- Fels Institute for Cancer Research and Molecular Biology, Temple University Lewis Katz School of Medicine, Philadelphia, PA, 19140, USA
| | - Jason S Wasserman
- Fels Institute for Cancer Research and Molecular Biology, Temple University Lewis Katz School of Medicine, Philadelphia, PA, 19140, USA
| | - Holly Fowle
- Fels Institute for Cancer Research and Molecular Biology, Temple University Lewis Katz School of Medicine, Philadelphia, PA, 19140, USA
| | - Tinsa Varughese
- Fels Institute for Cancer Research and Molecular Biology, Temple University Lewis Katz School of Medicine, Philadelphia, PA, 19140, USA
| | - Megan Connors
- Fels Institute for Cancer Research and Molecular Biology, Temple University Lewis Katz School of Medicine, Philadelphia, PA, 19140, USA
| | | | - Petr Makhov
- Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Cecilia Lindskog
- Department of Immunology, Genetics and Pathology, Uppsala University, 752 36, Uppsala, Sweden
| | | | | | | | - Xavier Graña
- Fels Institute for Cancer Research and Molecular Biology, Temple University Lewis Katz School of Medicine, Philadelphia, PA, 19140, USA.
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