1
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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] [MESH Headings] [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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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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Zhang C, Liu J, Wu J, Ranjan K, Cui X, Wang X, Zhang D, Zhu S. Key molecular DNA damage responses of human cells to radiation. Front Cell Dev Biol 2024; 12:1422520. [PMID: 39050891 PMCID: PMC11266142 DOI: 10.3389/fcell.2024.1422520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Accepted: 06/19/2024] [Indexed: 07/27/2024] Open
Abstract
Our understanding of the DNA damage responses of human cells to radiation has increased remarkably over the recent years although some notable signaling events remain to be discovered. Here we provide a brief account of the key molecular events of the responses to reflect the current understanding of the key underlying mechanisms involved.
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Affiliation(s)
- Chencheng Zhang
- Cancer Research Center, Nantong Tumor Hospital, Nantong, China
- Cancer Research Institute, The Affiliated Tumor Hospital of Nantong University, Nantong, China
- Cancer Research Center, Nantong, China
| | - Jibin Liu
- Cancer Research Center, Nantong Tumor Hospital, Nantong, China
- Cancer Research Institute, The Affiliated Tumor Hospital of Nantong University, Nantong, China
- Cancer Research Center, Nantong, China
| | - Jun Wu
- Nantong Tumor Hospital, Nantong, China
| | - Kamakshi Ranjan
- Department of Bio-Medical Sciences, Philadelphia College of Osteopathic Medicine, Philadelphia, PA, United States
| | - Xiaopeng Cui
- Department of General Surgery, The Affiliated Hospital of Nantong University, Nantong, China
| | - Xingdan Wang
- Department of Radiotherapy, Nantong Tumor Hospital, The Affiliated Tumor Hospital of Nantong University, Nantong, China
| | - Dianzheng Zhang
- Department of Bio-Medical Sciences, Philadelphia College of Osteopathic Medicine, Philadelphia, PA, United States
| | - Shudong Zhu
- Cancer Research Center, Nantong Tumor Hospital, Nantong, China
- Cancer Research Institute, The Affiliated Tumor Hospital of Nantong University, Nantong, China
- Cancer Research Center, Nantong, China
- Argus Pharmaceuticals, Changsha, China
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4
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Cokelaere C, Dok R, Cortesi EE, Zhao P, Sablina A, Nuyts S, Derua R, Janssens V. TIPRL1 and its ATM-dependent phosphorylation promote radiotherapy resistance in head and neck cancer. Cell Oncol (Dordr) 2024; 47:793-818. [PMID: 37971644 DOI: 10.1007/s13402-023-00895-6] [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] [Accepted: 10/23/2023] [Indexed: 11/19/2023] Open
Abstract
PURPOSE TIPRL1 (target of rapamycin signaling pathway regulator-like 1) is a known interactor and inhibitor of protein phosphatases PP2A, PP4 and PP6 - all pleiotropic modulators of the DNA Damage Response (DDR). Here, we investigated the role of TIPRL1 in the radiotherapy (RT) response of Head and Neck Squamous Cell Carcinoma (HNSCC). METHODS TIPRL1 mRNA (cBioportal) and protein expression (immunohistochemistry) in HNSCC samples were linked with clinical patient data. TIPRL1-depleted HNSCC cells were generated by CRISPR/Cas9 editing, and effects on colony growth, micronuclei formation (microscopy), cell cycle (flow cytometry), DDR signaling (immunoblots) and proteome (mass spectrometry) following RT were assessed. Mass spectrometry was used for TIPRL1 phosphorylation and interactomics analysis in irradiated cells. RESULTS TIPRL1 expression was increased in tumor versus non-tumor tissue, with high tumoral TIPRL1 expression associating with lower locoregional control and decreased survival of RT-treated patients. TIPRL1 deletion in HNSCC cells resulted in increased RT sensitivity, a faster but prolonged cell cycle arrest, increased micronuclei formation and an altered proteome-wide DDR. Upon irradiation, ATM phosphorylates TIPRL1 at Ser265. A non-phospho Ser265Ala mutant could not rescue the increased radiosensitivity phenotype of TIPRL1-depleted cells. While binding to PP2A-like phosphatases was confirmed, DNA-dependent protein kinase (DNA-PKcs), RAD51 recombinase and nucleosomal histones were identified as novel TIPRL1 interactors. Histone binding, although stimulated by RT, was adversely affected by TIPRL1 Ser265 phosphorylation. CONCLUSIONS Our findings underscore a clinically relevant role for TIPRL1 and its ATM-dependent phosphorylation in RT resistance through modulation of the DDR, highlighting its potential as a new HNSCC predictive marker and therapeutic target.
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Affiliation(s)
- Célie Cokelaere
- Laboratory of Protein Phosphorylation & Proteomics, Department of Cellular & Molecular Medicine, University of Leuven (KU Leuven), B-3000, Leuven, Belgium
- KU Leuven Cancer Institute (LKI), B-3000, Leuven, Belgium
| | - Rüveyda Dok
- KU Leuven Cancer Institute (LKI), B-3000, Leuven, Belgium
- Laboratory of Experimental Radiotherapy, Department of Oncology, University of Leuven (KU Leuven), B-3000, Leuven, Belgium
| | - Emanuela E Cortesi
- Translational Cell & Tissue Research, Department of Imaging & Pathology, University of Leuven (KU Leuven), B-3000, Leuven, Belgium
| | - Peihua Zhao
- VIB Laboratory of Mechanisms of Cell Transformation, Department of Oncology, University of Leuven (KU Leuven), B-3000, Leuven, Belgium
| | - Anna Sablina
- KU Leuven Cancer Institute (LKI), B-3000, Leuven, Belgium
- VIB Laboratory of Mechanisms of Cell Transformation, Department of Oncology, University of Leuven (KU Leuven), B-3000, Leuven, Belgium
| | - Sandra Nuyts
- KU Leuven Cancer Institute (LKI), B-3000, Leuven, Belgium
- Laboratory of Experimental Radiotherapy, Department of Oncology, 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, Proteomics Core Facility, University of Leuven (KU Leuven), B-3000, Leuven, Belgium
| | - Veerle Janssens
- Laboratory of Protein Phosphorylation & Proteomics, Department of Cellular & Molecular Medicine, University of Leuven (KU Leuven), B-3000, Leuven, Belgium.
- KU Leuven Cancer Institute (LKI), B-3000, Leuven, Belgium.
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5
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Qi Y, Li L, Wei Y, Ma F. PP2A as a potential therapeutic target for breast cancer: Current insights and future perspectives. Biomed Pharmacother 2024; 173:116398. [PMID: 38458011 DOI: 10.1016/j.biopha.2024.116398] [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: 12/16/2023] [Revised: 02/28/2024] [Accepted: 03/06/2024] [Indexed: 03/10/2024] Open
Abstract
Breast cancer has become the most prevalent malignancy worldwide; however, therapeutic efficacy is far from satisfactory. To alleviate the burden of this disease, it is imperative to discover novel mechanisms and treatment strategies. Protein phosphatase 2 A (PP2A) comprises a family of mammalian serine/threonine phosphatases that regulate many cellular processes. PP2A is dysregulated in several human diseases, including oncological pathologies, and plays a pivotal role in the initiation and progression of tumours. The role of PP2A as a tumour suppressor has been extensively studied, and its regulation can serve as a target for anticancer therapy. Recent studies have shown that PP2A is a tumour promotor. PP2A-mediated anticancer therapy may involve two opposing mechanisms: activation and inhibition. In general, the contradictory roles of PP2A should not be overlooked, and more work is needed to determine the molecular mechanism by which PP2A affects in tumours. In this review, the literature on the role of PP2A in tumours, especially in breast cancer, was analysed. This review describes relevant targets of breast cancer, such as cell cycle control, DNA damage responses, epidermal growth factor receptor, immune modulation and cell death resistance, which may lead to effective therapeutic strategies or influence drug development in breast cancer.
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Affiliation(s)
- Yalong Qi
- Department of Medical Oncology, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Chaoyang District, Pan jia yuan nan Road 17, Beijing 100021, China
| | - Lixi Li
- Department of Medical Oncology, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Chaoyang District, Pan jia yuan nan Road 17, Beijing 100021, China
| | - Yuhan Wei
- Department of Medical Oncology, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Chaoyang District, Pan jia yuan nan Road 17, Beijing 100021, China
| | - Fei Ma
- Department of Medical Oncology, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Chaoyang District, Pan jia yuan nan Road 17, Beijing 100021, China.
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6
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Casari E, Pizzul P, Rinaldi C, Gnugnoli M, Clerici M, Longhese MP. The PP2A phosphatase counteracts the function of the 9-1-1 axis in checkpoint activation. Cell Rep 2023; 42:113360. [PMID: 38007689 DOI: 10.1016/j.celrep.2023.113360] [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: 06/03/2023] [Revised: 09/25/2023] [Accepted: 10/13/2023] [Indexed: 11/27/2023] Open
Abstract
DNA damage elicits a checkpoint response depending on the Mec1/ATR kinase, which detects the presence of single-stranded DNA and activates the effector kinase Rad53/CHK2. In Saccharomyces cerevisiae, one of the signaling circuits leading to Rad53 activation involves the evolutionarily conserved 9-1-1 complex, which acts as a platform for the binding of Dpb11 and Rad9 (referred to as the 9-1-1 axis) to generate a protein complex that allows Mec1 activation. By examining the effects of both loss-of-function and hypermorphic mutations, here, we show that the Cdc55 and Tpd3 subunits of the PP2A phosphatase counteract activation of the 9-1-1 axis. The lack of this inhibitory function results in DNA-damage sensitivity, sustained checkpoint-mediated cell-cycle arrest, and impaired resection of DNA double-strand breaks. This PP2A anti-checkpoint role depends on the capacity of Cdc55 to interact with Ddc1 and to counteract Ddc1-Dpb11 complex formation by preventing Dpb11 recognition of Ddc1 phosphorylated on Thr602.
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Affiliation(s)
- Erika Casari
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Paolo Pizzul
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Carlo Rinaldi
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Marco Gnugnoli
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Michela Clerici
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Maria Pia Longhese
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy.
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7
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Moghbeli M. MicroRNAs as the pivotal regulators of cisplatin resistance in osteosarcoma. Pathol Res Pract 2023; 249:154743. [PMID: 37549518 DOI: 10.1016/j.prp.2023.154743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 08/03/2023] [Indexed: 08/09/2023]
Abstract
Osteosarcoma (OS) is an aggressive bone tumor that originates from mesenchymal cells. It is considered as the eighth most frequent childhood cancer that mainly affects the tibia and femur among the teenagers and young adults. OS can be usually diagnosed by a combination of MRI and surgical biopsy. The intra-arterial cisplatin (CDDP) and Adriamycin is one of the methods of choices for the OS treatment. CDDP induces tumor cell death by disturbing the DNA replication. Although, CDDP has a critical role in improving the clinical complication in OS patients, a high ratio of CDDP resistance is observed among these patients. Prolonged CDDP administrations have also serious side effects in normal tissues and organs. Therefore, the molecular mechanisms of CDDP resistance should be clarified to define the novel therapeutic modalities in OS. Multidrug resistance (MDR) can be caused by various cellular and molecular processes such as drug efflux, detoxification, and signaling pathways. MicroRNAs (miRNAs) are the key regulators of CDDP response by the post transcriptional regulation of target genes involved in MDR. In the present review we have discussed all of the miRNAs associated with CDDP response in OS cells. It was observed that the majority of reported miRNAs increased CDDP sensitivity in OS cells through the regulation of signaling pathways, apoptosis, transporters, and autophagy. This review highlights the miRNAs as reliable non-invasive markers for the prediction of CDDP response in OS patients.
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Affiliation(s)
- Meysam Moghbeli
- Department of Medical Genetics and Molecular Medicine, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran; Medical Genetics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
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8
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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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9
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Roy S, Zaker A, Mer A, D’Amours D. Large-scale phenogenomic analysis of human cancers uncovers frequent alterations affecting SMC5/6 complex components in breast cancer. NAR Cancer 2023; 5:zcad047. [PMID: 37705607 PMCID: PMC10495288 DOI: 10.1093/narcan/zcad047] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 08/09/2023] [Accepted: 08/22/2023] [Indexed: 09/15/2023] Open
Abstract
Cancer cells often experience large-scale alterations in genome architecture because of DNA damage and replication stress. Whether mutations in core regulators of chromosome structure can also lead to cancer-promoting loss in genome stability is not fully understood. To address this question, we conducted a systematic analysis of mutations affecting a global regulator of chromosome biology -the SMC5/6 complex- in cancer genomics cohorts. Analysis of 64 959 cancer samples spanning 144 tissue types and 199 different cancer genome studies revealed that the SMC5/6 complex is frequently altered in breast cancer patients. Patient-derived mutations targeting this complex associate with strong phenotypic outcomes such as loss of ploidy control and reduced overall survival. Remarkably, the phenotypic impact of several patient mutations can be observed in a heterozygous context, hence providing an explanation for a prominent role of SMC5/6 mutations in breast cancer pathogenesis. Overall, our findings suggest that genes encoding global effectors of chromosome architecture can act as key contributors to cancer development in humans.
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Affiliation(s)
- Shamayita Roy
- Ottawa Institute of Systems Biology, Department of Cellular and Molecular Medicine, University of Ottawa, Roger Guindon Hall, 451 Smyth Rd, Ottawa, ON K1H 8M5, Canada
| | - Arvin Zaker
- Department of Biochemistry, Microbiology & Immunology, University of Ottawa, Roger Guindon Hall, 451 Smyth Rd, Ottawa, ON K1H 8M5, Canada
| | - Arvind Mer
- Department of Biochemistry, Microbiology & Immunology, University of Ottawa, Roger Guindon Hall, 451 Smyth Rd, Ottawa, ON K1H 8M5, Canada
| | - Damien D’Amours
- Ottawa Institute of Systems Biology, Department of Cellular and Molecular Medicine, University of Ottawa, Roger Guindon Hall, 451 Smyth Rd, Ottawa, ON K1H 8M5, Canada
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10
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Cao R, Jones DTD, Pan L, Wang S, Rawson S, Aster JC, Blacklow SC. Molecular Mechanism of PP2A/B55α Inhibition by IER5. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.29.555174. [PMID: 37693604 PMCID: PMC10491241 DOI: 10.1101/2023.08.29.555174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
PP2A serine/threonine protein phosphatases are heterotrimeric complexes that have a wide range of essential physiologic functions. The B55α form of PP2A has critical roles in cell cycle regulation, mitotic exit, and the DNA damage response1-6. Its activity is modulated by additional regulatory proteins, such as ARPP197, FAM122A8, and IER59. However, the precise mechanisms underlying the modulation of PP2A activity by these proteins remain elusive. Here, we show that IER5 inhibits pTau dephosphorylation by PP2A/B55α in biochemical assays and report a cryoelectron microscopy structure of the PP2A/B55α-IER5 complex, which reveals that IER5 occludes a surface on B55α used for substrate recruitment10-12. Mutation of interface residues on IER5 interferes with recovery of B55α in co-immunoprecipitation assays and suppresses events in squamous carcinoma cells, such as KRT1 expression, that depend on inhibition of PP2A/B55α by IER59. These studies define the molecular basis for PP2A inhibition by IER5 and suggest a roadmap for selective pharmacologic modulation of PP2A/B55α complexes.
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Affiliation(s)
- Ruili Cao
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA USA
| | - Daniel TD Jones
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA USA
| | - Li Pan
- Department of Pathology, Brigham and Women’s Hospital, Boston, MA USA
| | - Shumei Wang
- Department of Pathology, Brigham and Women’s Hospital, Boston, MA USA
| | - Shaun Rawson
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA USA
| | - Jon C Aster
- Department of Pathology, Brigham and Women’s Hospital, Boston, MA USA
| | - Stephen C Blacklow
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA USA
- Department of Cancer Biology, Dana Farber Cancer Institute, Boston, MA USA
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11
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Avelar RA, Armstrong AJ, Carvette G, Gupta R, Puleo N, Colina JA, Joseph P, Sobeck AM, O'Connor CM, Raines B, Gandhi A, Dziubinski ML, Ma DS, Resnick K, Singh S, Zanotti K, Nagel C, Waggoner S, Thomas DG, Skala SL, Zhang J, Narla G, DiFeo A. Small-Molecule-Mediated Stabilization of PP2A Modulates the Homologous Recombination Pathway and Potentiates DNA Damage-Induced Cell Death. Mol Cancer Ther 2023; 22:599-615. [PMID: 36788429 PMCID: PMC10157366 DOI: 10.1158/1535-7163.mct-21-0880] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 05/17/2022] [Accepted: 02/09/2023] [Indexed: 02/16/2023]
Abstract
High-grade serous carcinoma (HGSC) is the most common and lethal ovarian cancer subtype. PARP inhibitors (PARPi) have become the mainstay of HGSC-targeted therapy, given that these tumors are driven by a high degree of genomic instability (GI) and homologous recombination (HR) defects. Nonetheless, approximately 30% of patients initially respond to treatment, ultimately relapsing with resistant disease. Thus, despite recent advances in drug development and an increased understanding of genetic alterations driving HGSC progression, mortality has not declined, highlighting the need for novel therapies. Using a small-molecule activator of protein phosphatase 2A (PP2A; SMAP-061), we investigated the mechanism by which PP2A stabilization induces apoptosis in patient-derived HGSC cells and xenograft (PDX) models alone or in combination with PARPi. We uncovered that PP2A genes essential for cellular transformation (B56α, B56γ, and PR72) and basal phosphatase activity (PP2A-A and -C) are heterozygously lost in the majority of HGSC. Moreover, loss of these PP2A genes correlates with worse overall patient survival. We show that SMAP-061-induced stabilization of PP2A inhibits the HR output by targeting RAD51, leading to chronic accumulation of DNA damage and ultimately apoptosis. Furthermore, combination of SMAP-061 and PARPi leads to enhanced apoptosis in both HR-proficient and HR-deficient HGSC cells and PDX models. Our studies identify PP2A as a novel regulator of HR and indicate PP2A modulators as a therapeutic therapy for HGSC. In summary, our findings further emphasize the potential of PP2A modulators to overcome PARPi insensitivity, given that targeting RAD51 presents benefits in overcoming PARPi resistance driven by BRCA1/2 mutation reversions.
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Affiliation(s)
- Rita A. Avelar
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
| | | | - Gracie Carvette
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
| | - Riya Gupta
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
| | - Noah Puleo
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
| | - Jose A. Colina
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
| | - Peronne Joseph
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio
| | - Alexander M. Sobeck
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
| | - Caitlin M. O'Connor
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
- Department of Internal Medicine, Genetic Medicine, University of Michigan, Ann Arbor, Michigan
| | - Brynne Raines
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
- Department of Internal Medicine, Genetic Medicine, University of Michigan, Ann Arbor, Michigan
| | - Agharnan Gandhi
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
| | - Michele L. Dziubinski
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
| | - Daniel S. Ma
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio
| | | | | | | | | | | | - Daffyd G. Thomas
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
| | | | - Junran Zhang
- Department of Radiation Oncology, Ohio State University, Columbus, Ohio
| | - Goutham Narla
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
- Department of Internal Medicine, Genetic Medicine, University of Michigan, Ann Arbor, Michigan
| | - Analisa DiFeo
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
- The Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, Michigan
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12
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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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13
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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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14
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Integrated Microarray-Based Data Analysis of miRNA Expression Profiles: Identification of Novel Biomarkers of Cisplatin-Resistance in Testicular Germ Cell Tumours. Int J Mol Sci 2023; 24:ijms24032495. [PMID: 36768818 PMCID: PMC9916636 DOI: 10.3390/ijms24032495] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/13/2023] [Accepted: 01/25/2023] [Indexed: 01/31/2023] Open
Abstract
Testicular germ cell tumours (TGCTs) are the most common solid malignancy among young men, and their incidence is still increasing. Despite good curability with cisplatin (CDDP)-based chemotherapy, about 10% of TGCTs are non-responsive and show a chemoresistant phenotype. To further increase TGCT curability, better prediction of risk of relapse and early detection of refractory cases is needed. Therefore, to diagnose this malignancy more precisely, stratify patients more accurately and improve decision-making on treatment modality, new biomarkers are still required. Numerous studies showed association of differential expressions of microRNAs (miRNAs) with cancer. Using microarray analysis followed by RT-qPCR validation, we identified specific miRNA expression patterns that discriminate chemoresistant phenotypes in TGCTs. Comparing CDDP-resistant vs. -sensitive TGCT cell lines, we identified miR-218-5p, miR-31-5p, miR-125b-5p, miR-27b-3p, miR-199a-5p, miR-214-3p, let-7a and miR-517a-3p as significantly up-regulated and miR-374b-5p, miR-378a-3p, miR-20b-5p and miR-30e-3p as significantly down-regulated. In patient tumour samples, we observed the highest median values of relative expression of miR-218-5p, miR-31-5p, miR-375-5p and miR-517a-3p, but also miR-20b-5p and miR-378a-3p, in metastatic tumour samples when compared with primary tumour or control samples. In TGCT patient plasma samples, we detected increased expression of miR-218-5p, miR-31-5p, miR-517a-3p and miR-375-5p when compared to healthy individuals. We propose that miR-218-5p, miR-31-5p, miR-375-5p, miR-517-3p, miR-20b-5p and miR-378a-3p represent a new panel of biomarkers for better prediction of chemoresistance and more aggressive phenotypes potentially underlying metastatic spread in non-seminomatous TGCTs. In addition, we provide predictions of the targets and functional and regulatory networks of selected miRNAs.
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15
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Haanen TJ, O'Connor CM, Narla G. Biased holoenzyme assembly of protein phosphatase 2A (PP2A): From cancer to small molecules. J Biol Chem 2022; 298:102656. [PMID: 36328247 PMCID: PMC9707111 DOI: 10.1016/j.jbc.2022.102656] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 10/25/2022] [Accepted: 10/27/2022] [Indexed: 11/06/2022] Open
Abstract
Protein phosphatase 2A (PP2A) is a family of serine threonine phosphatases responsible for regulating protein phosphorylation, thus opposing the activity of cellular kinases. PP2A is composed of a catalytic subunit (PP2A Cα/β) and scaffolding subunit (PP2A Aα/β) and various substrate-directing B regulatory subunits. PP2A biogenesis is regulated at multiple levels. For example, the sequestration of the free catalytic subunit during the process of biogenesis avoids promiscuous phosphatase activity. Posttranslational modifications of PP2A C direct PP2A heterotrimeric formation. Additionally, PP2A functions as a haploinsufficient tumor suppressor, where attenuated PP2A enzymatic activity creates a permissive environment for oncogenic transformation. Recent work studying PP2A in cancer showed that its role in tumorigenesis is more nuanced, with some holoenzymes being tumor suppressive, while others are required for oncogenic transformation. In cancer biology, PP2A function is modulated through various mechanisms including the displacement of specific B regulatory subunits by DNA tumor viral antigens, by recurrent mutations, and through loss of carboxymethyl-sensitive heterotrimeric complexes. In aggregate, these alterations bias PP2A activity away from its tumor suppressive functions and toward oncogenic ones. From a therapeutic perspective, molecular glues and disruptors present opportunities for both the selective stabilization of tumor-suppressive holoenzymes and disruption of holoenzymes that are pro-oncogenic. Collectively, these approaches represent an attractive cancer therapy for a wide range of tumor types. This review will discuss the mechanisms by which PP2A holoenzyme formation is dysregulated in cancer and the current therapies that are aimed at biasing heterotrimer formation of PP2A for the treatment of cancer.
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16
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Matsumoto T, Shiota M, Blas L, Eto M. Role of Olaparib in the Management of Metastatic Castration-Resistant Prostate Cancer: A Japanese Clinician's Perspective. Cancer Manag Res 2022; 14:2389-2397. [PMID: 35967752 PMCID: PMC9373991 DOI: 10.2147/cmar.s326114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Accepted: 08/01/2022] [Indexed: 11/23/2022] Open
Abstract
Several studies have identified various targetable genomic alterations in prostate cancer, which accumulate during carcinogenesis and cancer progression. Genomic alterations in genes involved in DNA damage repair by homologous recombination repair may predict increased sensitivity to poly-ADP ribose polymerase (PARP) inhibitors. The Phase 3 PROfound trial has shown that treatment with the PARP inhibitor olaparib was associated with an improved radiographic progression-free survival and overall survival among patients with homologous recombination repair-deficient metastatic castration-resistant prostate cancer (mCRPC) after the treatment with androgen receptor targeting therapy, especially in men with BRCA1 or BRCA2 mutation. In Japan, olaparib was approved in December 2020 for the treatment of mCRPC with BRCA1 or BRCA2 mutation. In addition, genetic tests to detect BRCA1 or BRCA2 mutation to select patients who are likely to benefit from olaparib were also approved. This review summarizes the status of olaparib treatment for mCRPC, focusing on the situation in Japan.
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Affiliation(s)
- Takashi Matsumoto
- Department of Urology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Masaki Shiota
- Department of Urology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Leandro Blas
- Department of Urology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Masatoshi Eto
- Department of Urology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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17
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Gulliver C, Hoffmann R, Baillie GS. Ataxia-telangiectasia mutated and ataxia telangiectasia and Rad3-related kinases as therapeutic targets and stratification indicators for prostate cancer. Int J Biochem Cell Biol 2022; 147:106230. [PMID: 35609768 DOI: 10.1016/j.biocel.2022.106230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 05/05/2022] [Accepted: 05/18/2022] [Indexed: 12/15/2022]
Abstract
The DNA damage response is an integral part of a cells' ability to maintain genomic integrity by responding to and ameliorating DNA damage, or initiating cell death for irrepairably damaged cells. This response is often hijacked by cancer cells to evade cell death allowing mutant cells to persist, as well as in the development of treatment resistance to DNA damaging agents such as chemotherapy and radiation. Prostate cancer (PCa) cells often exhibit alterations in DNA damage response genes including ataxia telangiectasia mutated (ATM), correlating with aggressive disease phenotype. The recent success of Poly (ADP-ribose) polymerase (PARP) inhibition has led to several clinically approved PARP inhibitors for the treatment of men with metastatic PCa, however a key limitation is the development of drug resistance and relapse. An alternative approach is selectively targeting ATM and ataxia telangiectasia and Rad3-related (ATR) which, due to their position at the forefront of the DDR, represent attractive pharmacological targets. ATR inhibition has been shown to act synergistically with PARP inhibition and other cancer treatments to enhance anti-tumour activity. ATM-deficiency is a common characteristic of PCa and a synthetic lethal relationship exists between ATM and ATR, with ATR inhibition inducing selective cell death in ATM-deficient PCa cells. The current research highlights the feasibility of therapeutically targeting ATR in ATM-deficient prostate tumours and in combination with other treatments to enhance overall efficacy and reduce therapeutic resistance. ATM also represents an important molecular biomarker to stratify patients into targeted treatment groups and aid prognosis for personalised medicine.
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Affiliation(s)
- Chloe Gulliver
- Institute of Cardiovascular and Medical Science, College of Veterinary, Medical and Life Science, University of Glasgow, Glasgow, UK.
| | - Ralf Hoffmann
- Institute of Cardiovascular and Medical Science, College of Veterinary, Medical and Life Science, University of Glasgow, Glasgow, UK; Philips Research Europe, High Tech Campus, Eindhoven, the Netherlands.
| | - George S Baillie
- Institute of Cardiovascular and Medical Science, College of Veterinary, Medical and Life Science, University of Glasgow, Glasgow, UK.
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18
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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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19
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O’Connor CM, Taylor SE, Miller KM, Hurst L, Haanen TJ, Suhan TK, Zawacki KP, Noto FK, Trako J, Mohan A, Sangodkar J, Zamarin D, DiFeo A, Narla G. Targeting Ribonucleotide Reductase Induces Synthetic Lethality in PP2A-Deficient Uterine Serous Carcinoma. Cancer Res 2022; 82:721-733. [PMID: 34921012 PMCID: PMC8857033 DOI: 10.1158/0008-5472.can-21-1987] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 10/14/2021] [Accepted: 11/30/2021] [Indexed: 11/16/2022]
Abstract
Uterine serous carcinoma (USC) is a highly aggressive endometrial cancer subtype with limited therapeutic options and a lack of targeted therapies. While mutations to PPP2R1A, which encodes the predominant protein phosphatase 2A (PP2A) scaffolding protein Aα, occur in 30% to 40% of USC cases, the clinical actionability of these mutations has not been studied. Using a high-throughput screening approach, we showed that mutations in Aα results in synthetic lethality following treatment with inhibitors of ribonucleotide reductase (RNR). In vivo, multiple models of Aα mutant uterine serous tumors were sensitive to clofarabine, an RNR inhibitor (RNRi). Aα-mutant cells displayed impaired checkpoint signaling upon RNRi treatment and subsequently accumulated more DNA damage than wild-type (WT) cells. Consistently, inhibition of PP2A activity using LB-100, a catalytic inhibitor, sensitized WT USC cells to RNRi. Analysis of The Cancer Genome Atlas data indicated that inactivation of PP2A, through loss of PP2A subunit expression, was prevalent in USC, with 88% of patients with USC harboring loss of at least one PP2A gene. In contrast, loss of PP2A subunit expression was rare in uterine endometrioid carcinomas. While RNRi are not routinely used for uterine cancers, a retrospective analysis of patients treated with gemcitabine as a second- or later-line therapy revealed a trend for improved outcomes in patients with USC treated with RNRi gemcitabine compared with patients with endometrioid histology. Overall, our data provide experimental evidence to support the use of ribonucleotide reductase inhibitors for the treatment of USC. SIGNIFICANCE A drug repurposing screen identifies synthetic lethal interactions in PP2A-deficient uterine serous carcinoma, providing potential therapeutic avenues for treating this deadly endometrial cancer.
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Affiliation(s)
- Caitlin M. O’Connor
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
- Rogel Cancer Center, The University of Michigan, Ann Arbor, Michigan
| | - Sarah E. Taylor
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio
| | - Kathryn M. Miller
- Department of Surgery, Memorial Sloan Kettering Cancer Center, New York City, New York
| | - Lauren Hurst
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
| | - Terrance J. Haanen
- Rogel Cancer Center, The University of Michigan, Ann Arbor, Michigan
- Department of Cancer Biology, The University of Michigan, Ann Arbor, Michigan
| | - Tahra K. Suhan
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
| | - Kaitlin P. Zawacki
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
| | | | - Jonida Trako
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
| | - Arathi Mohan
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
| | - Jaya Sangodkar
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
| | - Dmitriy Zamarin
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York City, New York
| | - Analisa DiFeo
- Rogel Cancer Center, The University of Michigan, Ann Arbor, Michigan
- Department of Pathology, The University of Michigan, Ann Arbor, Michigan
- Department of Obstetrics and Gynecology, The University of Michigan, Ann Arbor, Michigan
| | - Goutham Narla
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
- Rogel Cancer Center, The University of Michigan, Ann Arbor, Michigan
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20
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Sule A, Golding SE, Ahmad SF, Watson J, Ahmed MH, Kellogg GE, Bernas T, Koebley S, Reed JC, Povirk LF, Valerie K. ATM phosphorylates PP2A subunit A resulting in nuclear export and spatiotemporal regulation of the DNA damage response. Cell Mol Life Sci 2022; 79:603. [PMID: 36434396 PMCID: PMC9700600 DOI: 10.1007/s00018-022-04550-5] [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: 04/24/2022] [Revised: 08/30/2022] [Accepted: 09/07/2022] [Indexed: 11/26/2022]
Abstract
Ataxia telangiectasia mutated (ATM) is a serine-threonine protein kinase and important regulator of the DNA damage response (DDR). One critical ATM target is the structural subunit A (PR65-S401) of protein phosphatase 2A (PP2A), known to regulate diverse cellular processes such as mitosis and cell growth as well as dephosphorylating many proteins during the recovery from the DDR. We generated mouse embryonic fibroblasts expressing PR65-WT, -S401A (cannot be phosphorylated), and -S401D (phospho-mimetic) transgenes. Significantly, S401 mutants exhibited extensive chromosomal aberrations, impaired DNA double-strand break (DSB) repair and underwent increased mitotic catastrophe after radiation. Both S401A and the S401D cells showed impaired DSB repair (nonhomologous end joining and homologous recombination repair) and exhibited delayed DNA damage recovery, which was reflected in reduced radiation survival. Furthermore, S401D cells displayed increased ERK and AKT signaling resulting in enhanced growth rate further underscoring the multiple roles ATM-PP2A signaling plays in regulating prosurvival responses. Time-lapse video and cellular localization experiments showed that PR65 was exported to the cytoplasm after radiation by CRM1, a nuclear export protein, in line with the very rapid pleiotropic effects observed. A putative nuclear export sequence (NES) close to S401 was identified and when mutated resulted in aberrant PR65 shuttling. Our study demonstrates that the phosphorylation of a single, critical PR65 amino acid (S401) by ATM fundamentally controls the DDR, and balances DSB repair quality, cell survival and growth by spatiotemporal PR65 nuclear-cytoplasmic shuttling mediated by the nuclear export receptor CRM1.
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Affiliation(s)
- Amrita Sule
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, 23298-0058, USA
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Sarah E Golding
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, 23298-0058, USA
| | - Syed F Ahmad
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, 23298-0058, USA
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - James Watson
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, 23298-0058, USA
| | - Mostafa H Ahmed
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Glen E Kellogg
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA, 23298, USA
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Tytus Bernas
- Department of Anatomy, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Sean Koebley
- Department of Physics, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Jason C Reed
- Department of Physics, Virginia Commonwealth University, Richmond, VA, 23298, USA
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Lawrence F Povirk
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, 23298, USA
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Kristoffer Valerie
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, 23298-0058, USA.
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, 23298, USA.
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, 23298, USA.
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21
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PP2A-B55: substrates and regulators in the control of cellular functions. Oncogene 2022; 41:1-14. [PMID: 34686773 DOI: 10.1038/s41388-021-02068-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/29/2021] [Accepted: 10/06/2021] [Indexed: 12/17/2022]
Abstract
PP2A is a major serine/threonine phosphatase class involved in the regulation of cell signaling through the removal of protein phosphorylation. This class of phosphatases is comprised of different heterotrimeric complexes displaying distinct substrate specificities. The present review will focus on one specific heterocomplex, the phosphatase PP2A-B55. Herein, we will report the direct substrates of this phosphatase identified to date, and its impact on different cell signaling cascades. We will additionally describe its negative regulation by its inhibitors Arpp19 and ENSA and their upstream kinase Greatwall. Finally, we will describe the essential molecular features defining PP2A-B55 substrate specificity that confer the correct temporal pattern of substrate dephosphorylation. The main objective of this review is to provide the reader with a unique source compiling all the knowledge of this particular holoenzyme that has evolved as a key enzyme for cell homeostasis and cancer development.
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22
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A complex of BRCA2 and PP2A-B56 is required for DNA repair by homologous recombination. Nat Commun 2021; 12:5748. [PMID: 34593815 PMCID: PMC8484605 DOI: 10.1038/s41467-021-26079-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 09/13/2021] [Indexed: 12/12/2022] Open
Abstract
Mutations in the tumour suppressor gene BRCA2 are associated with predisposition to breast and ovarian cancers. BRCA2 has a central role in maintaining genome integrity by facilitating the repair of toxic DNA double-strand breaks (DSBs) by homologous recombination (HR). BRCA2 acts by controlling RAD51 nucleoprotein filament formation on resected single-stranded DNA, but how BRCA2 activity is regulated during HR is not fully understood. Here, we delineate a pathway where ATM and ATR kinases phosphorylate a highly conserved region in BRCA2 in response to DSBs. These phosphorylations stimulate the binding of the protein phosphatase PP2A-B56 to BRCA2 through a conserved binding motif. We show that the phosphorylation-dependent formation of the BRCA2-PP2A-B56 complex is required for efficient RAD51 filament formation at sites of DNA damage and HR-mediated DNA repair. Moreover, we find that several cancer-associated mutations in BRCA2 deregulate the BRCA2-PP2A-B56 interaction and sensitize cells to PARP inhibition. Collectively, our work uncovers PP2A-B56 as a positive regulator of BRCA2 function in HR with clinical implications for BRCA2 and PP2A-B56 mutated cancers.
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23
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Zhang Q, Fan Z, Zhang L, You Q, Wang L. Strategies for Targeting Serine/Threonine Protein Phosphatases with Small Molecules in Cancer. J Med Chem 2021; 64:8916-8938. [PMID: 34156850 DOI: 10.1021/acs.jmedchem.1c00631] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Among numerous posttranslational regulation patterns, phosphorylation is reversibly controlled by the balance of kinases and phosphatases. The major form of cellular signaling involves the reversible phosphorylation of proteins on tyrosine, serine, or threonine residues. However, altered phosphorylation levels are found in diverse diseases, including cancer, making kinases and phosphatases ideal drug targets. In contrast to the success of prosperous kinase inhibitors, design of small molecules targeting phosphatase is struggling due to past bias and difficulty. This is especially true for serine/threonine phosphatases, one of the largest phosphatase families. From this perspective, we aim to provide insights into serine/threonine phosphatases and the small molecules targeting these proteins for drug development, especially in cancer. Through highlighting the modulation strategies, we aim to provide basic principles for the design of small molecules and future perspectives for the application of drugs targeting serine/threonine phosphatases.
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Affiliation(s)
- Qiuyue Zhang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Zhongjiao Fan
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Lianshan Zhang
- Shanghai Hengrui Pharmaceutical Co., Ltd., Shanghai 200245, China
| | - Qidong You
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Lei Wang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
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24
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Bryant JP, Levy A, Heiss J, Banasavadi-Siddegowda YK. Review of PP2A Tumor Biology and Antitumor Effects of PP2A Inhibitor LB100 in the Nervous System. Cancers (Basel) 2021; 13:cancers13123087. [PMID: 34205611 PMCID: PMC8235527 DOI: 10.3390/cancers13123087] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/17/2021] [Accepted: 06/18/2021] [Indexed: 12/14/2022] Open
Abstract
Simple Summary Central and peripheral nervous system tumors represent a heterogenous group of neoplasms which often demonstrate resistance to treatment. Given that these tumors are often refractory to conventional therapy, novel pharmaceutical regimens are needed for successfully treating this pathology. One such therapeutic is the serine/threonine phosphatase inhibitor, LB100. LB100 is a water-soluble competitive protein phosphtase inhibitor that has demonstrated antitumor effects in preclinical and clinical trials. In this review, we aim to summarize current evidence demonstrating the efficacy of LB100 as an inhibitor of nervous system tumors. Furthermore, we review the involvement of the well-studied phosphatase, protein phosphatase 2A, in oncogenic cell signaling pathways, neurophysiology, and neurodevelopment. Abstract Protein phosphatase 2A (PP2A) is a ubiquitous serine/threonine phosphatase implicated in a wide variety of regulatory cellular functions. PP2A is abundant in the mammalian nervous system, and dysregulation of its cellular functions is associated with myriad neurodegenerative disorders. Additionally, PP2A has oncologic implications, recently garnering attention and emerging as a therapeutic target because of the antitumor effects of a potent PP2A inhibitor, LB100. LB100 abrogation of PP2A is believed to exert its inhibitory effects on tumor progression through cellular chemo- and radiosensitization to adjuvant agents. An updated and unifying review of PP2A biology and inhibition with LB100 as a therapeutic strategy for targeting cancers of the nervous system is needed, as other reviews have mainly covered broader applications of LB100. In this review, we discuss the role of PP2A in normal cells and tumor cells of the nervous system. Furthermore, we summarize current evidence regarding the therapeutic potential of LB100 for treating solid tumors of the nervous system.
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Affiliation(s)
- Jean-Paul Bryant
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA; (J.-P.B.); (J.H.)
| | - Adam Levy
- Miller School of Medicine, University of Miami, Miami, FL 33136, USA;
| | - John Heiss
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA; (J.-P.B.); (J.H.)
| | - Yeshavanth Kumar Banasavadi-Siddegowda
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA; (J.-P.B.); (J.H.)
- Correspondence: ; Tel.: +1-301-451-0970
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25
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Perfecting DNA double-strand break repair on transcribed chromatin. Essays Biochem 2021; 64:705-719. [PMID: 32309851 DOI: 10.1042/ebc20190094] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 03/29/2020] [Accepted: 04/01/2020] [Indexed: 02/07/2023]
Abstract
Timely repair of DNA double-strand break (DSB) entails coordination with the local higher order chromatin structure and its transaction activities, including transcription. Recent studies are uncovering how DSBs trigger transient suppression of nearby transcription to permit faithful DNA repair, failing of which leads to elevated chromosomal aberrations and cell hypersensitivity to DNA damage. Here, we summarize the molecular bases for transcriptional control during DSB metabolism, and discuss how the exquisite coordination between the two DNA-templated processes may underlie maintenance of genome stability and cell homeostasis.
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26
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Fernando M, Duijf PHG, Proctor M, Stevenson AJ, Ehmann A, Vora S, Skalamera D, Adams M, Gabrielli B. Dysregulated G2 phase checkpoint recovery pathway reduces DNA repair efficiency and increases chromosomal instability in a wide range of tumours. Oncogenesis 2021; 10:41. [PMID: 33993200 PMCID: PMC8124070 DOI: 10.1038/s41389-021-00329-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 04/06/2021] [Accepted: 04/20/2021] [Indexed: 11/12/2022] Open
Abstract
Defective DNA repair is being demonstrated to be a useful target in cancer treatment. Currently, defective repair is identified by specific gene mutations, however defective repair is a common feature of cancers without these mutations. DNA damage triggers cell cycle checkpoints that are responsible for co-ordinating cell cycle arrest and DNA repair. Defects in checkpoint signalling components such as ataxia telangiectasia mutated (ATM) occur in a low proportion of cancers and are responsible for reduced DNA repair and increased genomic instability. Here we have investigated the AURKA-PLK1 cell cycle checkpoint recovery pathway that is responsible for exit from the G2 phase cell cycle checkpoint arrest. We demonstrate that dysregulation of PP6 and AURKA maintained elevated PLK1 activation to promote premature exit from only ATM, and not ATR-dependent checkpoint arrest. Surprisingly, depletion of the B55α subunit of PP2A that negatively regulates PLK1 was capable of overcoming ATM and ATR checkpoint arrests. Dysregulation of the checkpoint recovery pathway reduced S/G2 phase DNA repair efficiency and increased genomic instability. We found a strong correlation between dysregulation of the PP6-AURKA-PLK1-B55α checkpoint recovery pathway with signatures of defective homologous recombination and increased chromosomal instability in several cancer types. This work has identified an unrealised source of G2 phase DNA repair defects and chromosomal instability that are likely to be sensitive to treatments targeting defective repair.
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Affiliation(s)
- Madushan Fernando
- Mater Research Institute-The University of Queensland, Brisbane, QLD, Australia
| | - Pascal H G Duijf
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Faculty of Health, School of Biomedical Sciences, Brisbane, QLD, Australia
- Centre for Data Science, Queensland University of Technology (QUT), Brisbane, QLD, Australia
- University of Queensland Diamantina Institute, The University of Queensland, Translational Research Institute, Brisbane, QLD, Australia
| | - Martina Proctor
- Mater Research Institute-The University of Queensland, Brisbane, QLD, Australia
| | | | - Anna Ehmann
- Mater Research Institute-The University of Queensland, Brisbane, QLD, Australia
| | - Shivam Vora
- Mater Research Institute-The University of Queensland, Brisbane, QLD, Australia
| | - Dubravka Skalamera
- Mater Research Institute-The University of Queensland, Brisbane, QLD, Australia
| | - Mark Adams
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Faculty of Health, School of Biomedical Sciences, Brisbane, QLD, Australia
| | - Brian Gabrielli
- Mater Research Institute-The University of Queensland, Brisbane, QLD, Australia.
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27
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Biayna J, Garcia-Cao I, Álvarez MM, Salvadores M, Espinosa-Carrasco J, McCullough M, Supek F, Stracker TH. Loss of the abasic site sensor HMCES is synthetic lethal with the activity of the APOBEC3A cytosine deaminase in cancer cells. PLoS Biol 2021; 19:e3001176. [PMID: 33788831 PMCID: PMC8041192 DOI: 10.1371/journal.pbio.3001176] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 04/12/2021] [Accepted: 03/08/2021] [Indexed: 12/26/2022] Open
Abstract
Analysis of cancer mutagenic signatures provides information about the origin of mutations and can inform the use of clinical therapies, including immunotherapy. In particular, APOBEC3A (A3A) has emerged as a major driver of mutagenesis in cancer cells, and its expression results in DNA damage and susceptibility to treatment with inhibitors of the ATR and CHK1 checkpoint kinases. Here, we report the implementation of CRISPR/Cas-9 genetic screening to identify susceptibilities of multiple A3A-expressing lung adenocarcinoma (LUAD) cell lines. We identify HMCES, a protein recently linked to the protection of abasic sites, as a central protein for the tolerance of A3A expression. HMCES depletion results in synthetic lethality with A3A expression preferentially in a TP53-mutant background. Analysis of previous screening data reveals a strong association between A3A mutational signatures and sensitivity to HMCES loss and indicates that HMCES is specialized in protecting against a narrow spectrum of DNA damaging agents in addition to A3A. We experimentally show that both HMCES disruption and A3A expression increase susceptibility of cancer cells to ionizing radiation (IR), oxidative stress, and ATR inhibition, strategies that are often applied in tumor therapies. Overall, our results suggest that HMCES is an attractive target for selective treatment of A3A-expressing tumors.
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Affiliation(s)
- Josep Biayna
- Genome Data Science, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Isabel Garcia-Cao
- Genomic Instability and Cancer, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Miguel M. Álvarez
- Genome Data Science, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Marina Salvadores
- Genome Data Science, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Jose Espinosa-Carrasco
- Genome Data Science, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Marcel McCullough
- Genome Data Science, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Fran Supek
- Genome Data Science, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
- * E-mail: (FS); (THS)
| | - Travis H. Stracker
- Genomic Instability and Cancer, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
- National Cancer Institute, Center for Cancer Research, Radiation Oncology Branch, Bethesda, Maryland, United States of America
- * E-mail: (FS); (THS)
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28
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Tadros S, Kondrashov A, Namagiri S, Chowdhury A, Banasavadi-Siddegowda YK, Ray-Chaudhury A. Pathological Features of Tumors of the Nervous System in Hereditary Cancer Predisposition Syndromes: A Review. Neurosurgery 2021; 89:343-363. [PMID: 33693933 DOI: 10.1093/neuros/nyab019] [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: 06/07/2020] [Accepted: 12/13/2020] [Indexed: 11/13/2022] Open
Abstract
Hereditary cancer predisposition syndromes (HCS) become more recognizable as the knowledge about them expands, and genetic testing becomes more affordable. In this review, we discussed the known HCS that predispose to central and peripheral nervous system tumors. Different genetic phenomena were highlighted, and the important cellular biological alterations were summarized. Genetic mosaicism and germline mutations are features of HCS, and recently, they were described in normal population and as modifiers for the genetic landscape of sporadic tumors. Description of the tumors arising in these conditions was augmented by representative cases explaining the main pathological findings. Clinical spectrum of the syndromes and diagnostic criteria were tabled to outline their role in defining these disorders. Interestingly, precision medicine has found its way to help these groups of patients by offering targeted preventive measures. Understanding the signaling pathway alteration of mammalian target of rapamycin (mTOR) in tuberous sclerosis helped introducing mTOR inhibitors as a prophylactic treatment in these patients. More research to define the germline genetic alterations and resulting cellular signaling perturbations is needed for effective risk-reducing interventions beyond prophylactic surgeries.
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Affiliation(s)
- Saber Tadros
- Laboratory of Pathology, National Cancer Institute , National Institutes of Health, Bethesda, Maryland, USA
| | - Aleksei Kondrashov
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA.,Faculty of Medicine, Moscow State University, Moscow, Russia
| | - Sriya Namagiri
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Ashis Chowdhury
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | | | - Abhik Ray-Chaudhury
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
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29
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Zhao J, Chen G, Li J, Liu S, Jin Q, Zhang Z, Qi F, Zhang J, Xu J. Loss of PR55α promotes proliferation and metastasis by activating MAPK/AKT signaling in hepatocellular carcinoma. Cancer Cell Int 2021; 21:107. [PMID: 33588847 PMCID: PMC7885213 DOI: 10.1186/s12935-021-01796-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 01/27/2021] [Indexed: 12/25/2022] Open
Abstract
Background PR55α plays important roles in oncogenesis and progression of numerous malignancies. However, its role in hepatocellular carcinoma (HCC) is unclear. This study aims to characterize the functions of PR55α in HCC. Methods
PR55α expressions in HCC tissues and paired healthy liver samples were evaluated using Western blot and tissue microarray immunohistochemistry. We knocked down the expression of PR55α in SMMC-7721 and LM3 cell lines via small interfering and lentivirus. In vitro cell counting, colony formation, migration and invasion assays were performed along with in vivo xenograft implantation and lung metastases experiments. The potential mechanisms involving target signal pathways were investigated by RNA-sequencing. Results PR55α expression level was suppressed in HCC tissues in comparison to healthy liver samples. Decreased PR55α levels were correlated with poorer prognosis (P = 0.0059). Knockdown of PR55α significantly promoted cell proliferation and migration, induced repression of the cell cycle progression and apoptosis in vitro while accelerating in vivo HCC growth and metastasis. Mechanistic analysis indicated that PR55α silencing was involved with MAPK/AKT signal pathway activation and resulted in increased phosphorylation of both AKT and ERK1/2. Conclusions This study identifies PR55α to be a candidate novel therapeutic target in the treatment of HCC.
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Affiliation(s)
- JiangSheng Zhao
- Department of Hepatobiliary Surgery, The Affiliated Huaian NO.1 People's Hospital of Nanjing Medical University, Huai'an, 223001, Jiangsu, People's Republic of China
| | - GuoFeng Chen
- Department of Hepatobiliary Surgery, The Affiliated Huaian NO.1 People's Hospital of Nanjing Medical University, Huai'an, 223001, Jiangsu, People's Republic of China
| | - Jingqi Li
- Department of Pathology, The Affiliated Huaian NO.1 People's Hospital of Nanjing Medical University, Huai'an, 223001, Jiangsu, People's Republic of China
| | - Shiqi Liu
- Department of Hepatobiliary Surgery, The Affiliated Huaian NO.1 People's Hospital of Nanjing Medical University, Huai'an, 223001, Jiangsu, People's Republic of China
| | - Quan Jin
- Department of Hepatobiliary Surgery, The Affiliated Huaian NO.1 People's Hospital of Nanjing Medical University, Huai'an, 223001, Jiangsu, People's Republic of China
| | - ZhengWei Zhang
- Department of Pathology, The Affiliated Huaian NO.1 People's Hospital of Nanjing Medical University, Huai'an, 223001, Jiangsu, People's Republic of China
| | - Fuzhen Qi
- Department of Hepatobiliary Surgery, The Affiliated Huaian NO.1 People's Hospital of Nanjing Medical University, Huai'an, 223001, Jiangsu, People's Republic of China
| | - JianHuai Zhang
- Department of Hepatobiliary Surgery, The Affiliated Huaian NO.1 People's Hospital of Nanjing Medical University, Huai'an, 223001, Jiangsu, People's Republic of China
| | - JianBo Xu
- Department of Hepatobiliary Surgery, The Affiliated Huaian NO.1 People's Hospital of Nanjing Medical University, Huai'an, 223001, Jiangsu, People's Republic of China.
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30
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Christodoulou E, Rashid M, Pacini C, Droop A, Robertson H, van Groningen T, Teunisse AFAS, Iorio F, Jochemsen AG, Adams DJ, van Doorn R. Analysis of CRISPR-Cas9 screens identifies genetic dependencies in melanoma. Pigment Cell Melanoma Res 2021; 34:122-131. [PMID: 32767816 PMCID: PMC7818247 DOI: 10.1111/pcmr.12919] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/03/2020] [Accepted: 07/29/2020] [Indexed: 12/13/2022]
Abstract
Targeting the MAPK signaling pathway has transformed the treatment of metastatic melanoma. CRISPR-Cas9 genetic screens provide a genome-wide approach to uncover novel genetic dependencies that might serve as therapeutic targets. Here, we analyzed recently reported CRISPR-Cas9 screens comparing data from 28 melanoma cell lines and 313 cell lines of other tumor types in order to identify fitness genes related to melanoma. We found an average of 1,494 fitness genes in each melanoma cell line. We identified 33 genes, inactivation of which specifically reduced the fitness of melanoma. This set of tumor type-specific genes includes established melanoma fitness genes as well as many genes that have not previously been associated with melanoma growth. Several genes encode proteins that can be targeted using available inhibitors. We verified that genetic inactivation of DUSP4 and PPP2R2A reduces the proliferation of melanoma cells. DUSP4 encodes an inhibitor of ERK, suggesting that further activation of MAPK signaling activity through its loss is selectively deleterious to melanoma cells. Collectively, these data present a resource of genetic dependencies in melanoma that may be explored as potential therapeutic targets.
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Affiliation(s)
| | - Mamunur Rashid
- Experimental Cancer Genetics GroupWellcome Trust Sanger InstituteCambridgeUK
| | - Clare Pacini
- Cancer Dependency Map AnalyticsWellcome Trust Sanger InstituteCambridgeUK
| | - Alastair Droop
- Experimental Cancer Genetics GroupWellcome Trust Sanger InstituteCambridgeUK
| | - Holly Robertson
- Experimental Cancer Genetics GroupWellcome Trust Sanger InstituteCambridgeUK
| | - Tim van Groningen
- Department of DermatologyLeiden University Medical CenterLeidenThe Netherlands
| | - Amina F. A. S. Teunisse
- Department of Cell and Chemical BiologyLeiden University Medical CenterLeidenThe Netherlands
| | - Francesco Iorio
- Cancer Dependency Map AnalyticsWellcome Trust Sanger InstituteCambridgeUK
- Centre for Computational BiologyHuman TechnopoleMilanoItaly
| | - Aart G. Jochemsen
- Department of Cell and Chemical BiologyLeiden University Medical CenterLeidenThe Netherlands
| | - David J. Adams
- Experimental Cancer Genetics GroupWellcome Trust Sanger InstituteCambridgeUK
| | - Remco van Doorn
- Department of DermatologyLeiden University Medical CenterLeidenThe Netherlands
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31
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Goguet-Rubio P, Amin P, Awal S, Vigneron S, Charrasse S, Mechali F, Labbé JC, Lorca T, Castro A. PP2A-B55 Holoenzyme Regulation and Cancer. Biomolecules 2020; 10:biom10111586. [PMID: 33266510 PMCID: PMC7700614 DOI: 10.3390/biom10111586] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 11/18/2020] [Accepted: 11/19/2020] [Indexed: 01/05/2023] Open
Abstract
Protein phosphorylation is a post-translational modification essential for the control of the activity of most enzymes in the cell. This protein modification results from a fine-tuned balance between kinases and phosphatases. PP2A is one of the major serine/threonine phosphatases that is involved in the control of a myriad of different signaling cascades. This enzyme, often misregulated in cancer, is considered a tumor suppressor. In this review, we will focus on PP2A-B55, a particular holoenzyme of the family of the PP2A phosphatases whose specific role in cancer development and progression has only recently been highlighted. The discovery of the Greatwall (Gwl)/Arpp19-ENSA cascade, a new pathway specifically controlling PP2A-B55 activity, has been shown to be frequently altered in cancer. Herein, we will review the current knowledge about the mechanisms controlling the formation and the regulation of the activity of this phosphatase and its misregulation in cancer.
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32
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Qiu Z, Fa P, Liu T, Prasad CB, Ma S, Hong Z, Chan ER, Wang H, Li Z, He K, Wang QE, Williams TM, Yan C, Sizemore ST, Narla G, Zhang J. A Genome-Wide Pooled shRNA Screen Identifies PPP2R2A as a Predictive Biomarker for the Response to ATR and CHK1 Inhibitors. Cancer Res 2020; 80:3305-3318. [PMID: 32522823 PMCID: PMC7518641 DOI: 10.1158/0008-5472.can-20-0057] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 04/17/2020] [Accepted: 06/04/2020] [Indexed: 01/18/2023]
Abstract
There is currently a lack of precise predictive biomarkers for patient selection in clinical trials of inhibitors targeting replication stress (RS) response proteins ATR and CHK1. The objective of this study was to identify novel predictive biomarkers for the response to these agents in treating non-small cell lung cancer (NSCLC). A genome-wide loss-of-function screen revealed that tumor suppressor PPP2R2A, a B regulatory subunit of protein phosphatase 2 (PP2A), determines sensitivity to CHK1 inhibition. A synthetic lethal interaction between PPP2R2A deficiency and ATR or CHK1 inhibition was observed in NSCLC in vitro and in vivo and was independent of p53 status. ATR and CHK1 inhibition resulted in significantly increased levels of RS and altered replication dynamics, particularly in PPP2R2A-deficient NSCLC cells. Mechanistically, PPP2R2A negatively regulated translation of oncogene c-Myc protein. c-Myc activity was required for PPP2R2A deficiency-induced alterations of replication initiation/RS and sensitivity to ATR/CHK1 inhibitors. We conclude that PPP2R2A deficiency elevates RS by upregulating c-Myc activity, rendering cells reliant on the ATR/CHK1 axis for survival. Our studies show a novel synthetic lethal interaction and identify PPP2R2A as a potential new predictive biomarker for patient stratification in the clinical use of ATR and CHK1 inhibitors. SIGNIFICANCE: This study reveals new approaches to specifically target PPP2R2A-deficient lung cancer cells and provides a novel biomarker that will significantly improve treatment outcome with ATR and CHK1 inhibitors.
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MESH Headings
- Animals
- Ataxia Telangiectasia Mutated Proteins/antagonists & inhibitors
- Biomarkers, Tumor/deficiency
- Biomarkers, Tumor/genetics
- Biomarkers, Tumor/metabolism
- Carcinoma, Non-Small-Cell Lung/chemistry
- Carcinoma, Non-Small-Cell Lung/drug therapy
- Carcinoma, Non-Small-Cell Lung/genetics
- Carcinoma, Non-Small-Cell Lung/metabolism
- Cell Line, Tumor
- Checkpoint Kinase 1/antagonists & inhibitors
- DNA Damage
- DNA Replication
- Drug Resistance, Neoplasm
- Female
- Gene Knockdown Techniques
- Genes, p53
- Genome-Wide Association Study
- Heterografts
- Humans
- Lung Neoplasms/chemistry
- Lung Neoplasms/drug therapy
- Lung Neoplasms/genetics
- Lung Neoplasms/metabolism
- Male
- Mice
- Mice, Nude
- Protein Phosphatase 2/deficiency
- Protein Phosphatase 2/genetics
- Protein Phosphatase 2/metabolism
- Proto-Oncogene Proteins c-myc/metabolism
- RNA, Small Interfering
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Affiliation(s)
- Zhaojun Qiu
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, Ohio
| | - Pengyan Fa
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, Ohio
| | - Tao Liu
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, Ohio
| | - Chandra B Prasad
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, Ohio
| | - Shanhuai Ma
- University of Rochester, Rochester, New York
| | - Zhipeng Hong
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, Ohio
| | - Ernest R Chan
- Institute for Computational Biology, Case Western Reserve University, Cleveland, Ohio
| | - Hongbing Wang
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland
| | - Zaibo Li
- Department of Pathology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, Ohio
| | - Kai He
- Department of Internal Medicine, The Ohio State University James Comprehensive Cancer Center and College of Medicine, Ohio
| | - Qi-En Wang
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, Ohio
| | - Terence M Williams
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, Ohio
| | - Chunhong Yan
- Georgia Cancer Center, Augusta University, Augusta, Georgia
| | - Steven T Sizemore
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, Ohio
| | - Goutham Narla
- Department of Medicine, University of Michigan, Ann Arbor, Michigan
| | - Junran Zhang
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, Ohio.
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Panicker N, Coutman M, Lawlor-O’Neill C, Kahl RGS, Roselli S, Verrills NM. Ppp2r2a Knockout Mice Reveal That Protein Phosphatase 2A Regulatory Subunit, PP2A-B55α, Is an Essential Regulator of Neuronal and Epidermal Embryonic Development. Front Cell Dev Biol 2020; 8:358. [PMID: 32582689 PMCID: PMC7290052 DOI: 10.3389/fcell.2020.00358] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 04/22/2020] [Indexed: 12/13/2022] Open
Abstract
The serine/threonine protein phosphatase 2A (PP2A) is a master regulator of the complex cellular signaling that occurs during all stages of mammalian development. PP2A is composed of a catalytic, a structural, and regulatory subunit, for which there are multiple isoforms. The association of specific regulatory subunits determines substrate specificity and localization of phosphatase activity, however, the precise role of each regulatory subunit in development is not known. Here we report the generation of the first knockout mouse for the Ppp2r2a gene, encoding the PP2A-B55α regulatory subunit, using CRISPR/Cas9. Heterozygous animals developed and grew as normal, however, homozygous knockout mice were not viable. Analysis of embryos at different developmental stages found a normal Mendelian ratio of Ppp2r2a-/- embryos at embryonic day (E) 10.5 (25%), but reduced Ppp2r2a-/- embryos at E14.5 (18%), and further reduced at E18.5 (10%). No live Ppp2r2a-/- pups were observed at birth. Ppp2r2a-/- embryos were significantly smaller than wild-type or heterozygous littermates and displayed a variety of neural defects such as exencephaly, spina bifida, and cranial vault collapse, as well as syndactyly and severe epidermal defects; all processes driven by growth and differentiation of the ectoderm. Ppp2r2a-/- embryos had incomplete epidermal barrier acquisition, associated with thin, poorly differentiated stratified epithelium with weak attachment to the underlying dermis. The basal keratinocytes in Ppp2r2a-/- embryos were highly disorganized, with reduced immunolabeling of integrins and basement membrane proteins, suggesting impaired focal adhesion and hemidesmosome assembly. The spinous and granular layers were thinner in the Ppp2r2a-/- embryos, with aberrant expression of adherens and tight junction associated proteins. The overlying stratum corneum was either absent or incomplete. Thus PP2A-B55α is an essential regulator of epidermal stratification, and is essential for ectodermal development during embryogenesis.
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Affiliation(s)
- Nikita Panicker
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, Priority Research Centre for Cancer Research, Innovation and Translation, University of Newcastle, Callaghan, NSW, Australia
- Hunter Cancer Research Alliance, Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Melody Coutman
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, Priority Research Centre for Cancer Research, Innovation and Translation, University of Newcastle, Callaghan, NSW, Australia
- Hunter Cancer Research Alliance, Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Charley Lawlor-O’Neill
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, Priority Research Centre for Cancer Research, Innovation and Translation, University of Newcastle, Callaghan, NSW, Australia
- Hunter Cancer Research Alliance, Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Richard G. S. Kahl
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, Priority Research Centre for Cancer Research, Innovation and Translation, University of Newcastle, Callaghan, NSW, Australia
- Hunter Cancer Research Alliance, Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Séverine Roselli
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, Priority Research Centre for Cancer Research, Innovation and Translation, University of Newcastle, Callaghan, NSW, Australia
- Hunter Cancer Research Alliance, Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Nicole M. Verrills
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, Priority Research Centre for Cancer Research, Innovation and Translation, University of Newcastle, Callaghan, NSW, Australia
- Hunter Cancer Research Alliance, Hunter Medical Research Institute, New Lambton, NSW, Australia
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34
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Gonzalez-Rajal A, Hastings JF, Watkins DN, Croucher DR, Burgess A. Breathing New Life into the Mechanisms of Platinum Resistance in Lung Adenocarcinoma. Front Cell Dev Biol 2020; 8:305. [PMID: 32457904 PMCID: PMC7225257 DOI: 10.3389/fcell.2020.00305] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 04/07/2020] [Indexed: 12/25/2022] Open
Affiliation(s)
| | - Jordan F. Hastings
- The Kinghorn Cancer Centre, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - D. Neil Watkins
- Research Institute in Oncology and Hematology, Cancer Care Manitoba, Winnipeg, MB, Canada
- Department of Internal Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - David R. Croucher
- The Kinghorn Cancer Centre, Garvan Institute of Medical Research, Sydney, NSW, Australia
- St Vincent's Hospital Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Andrew Burgess
- ANZAC Research Institute, Concord, NSW, Australia
- The University of Sydney Concord Clinical School, Faculty of Medicine and Health, Sydney, NSW, Australia
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35
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Wang Z, Xu C, Diplas BH, Moure CJ, Chen CPJ, Chen LH, Du C, Zhu H, Greer PK, Zhang L, He Y, Waitkus MS, Yan H. Targeting Mutant PPM1D Sensitizes Diffuse Intrinsic Pontine Glioma Cells to the PARP Inhibitor Olaparib. Mol Cancer Res 2020; 18:968-980. [PMID: 32229503 DOI: 10.1158/1541-7786.mcr-19-0507] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 12/09/2019] [Accepted: 03/24/2020] [Indexed: 11/16/2022]
Abstract
Diffuse intrinsic pontine glioma (DIPG) is an invariably fatal brain tumor occurring predominantly in children. Up to 90% of pediatric DIPGs harbor a somatic heterozygous mutation resulting in the replacement of lysine 27 with methionine (K27M) in genes encoding histone H3.3 (H3F3A, 65%) or H3.1 (HIST1H3B, 25%). Several studies have also identified recurrent truncating mutations in the gene encoding protein phosphatase 1D, PPM1D, in 9%-23% of DIPGs. Here, we sought to investigate the therapeutic potential of targeting PPM1D, alone or in combination with inhibitors targeting specific components of DNA damage response pathways in patient-derived DIPG cell lines. We found that GSK2830371, an allosteric PPM1D inhibitor, suppressed the proliferation of PPM1D-mutant, but not PPM1D wild-type DIPG cells. We further observed that PPM1D inhibition sensitized PPM1D-mutant DIPG cells to PARP inhibitor (PARPi) treatment. Mechanistically, combined PPM1D and PARP inhibition show synergistic effects on suppressing a p53-dependent RAD51 expression and the formation of RAD51 nuclear foci, possibly leading to impaired homologous recombination (HR)-mediated DNA repair in PPM1D-mutant DIPG cells. Collectively, our findings reveal the potential role of the PPM1D-p53 signaling axis in the regulation of HR-mediated DNA repair and provide preclinical evidence demonstrating that combined inhibition of PPM1D and PARP1/2 may be a promising therapeutic combination for targeting PPM1D-mutant DIPG tumors. IMPLICATIONS: The findings support the use of PARPi in combination with PPM1D inhibition against PPM1D-mutant DIPGs.
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Affiliation(s)
- Zhaohui Wang
- Department of Pathology, Duke University, Durham, North Carolina.,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
| | - Cheng Xu
- Department of Pathology, Duke University, Durham, North Carolina.,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
| | - Bill H Diplas
- Department of Pathology, Duke University, Durham, North Carolina.,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
| | - Casey J Moure
- Department of Pathology, Duke University, Durham, North Carolina.,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
| | - Chin-Pu Jason Chen
- Department of Pathology, Duke University, Durham, North Carolina.,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
| | - Lee H Chen
- Department of Pathology, Duke University, Durham, North Carolina.,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
| | - Changzheng Du
- Department of Pathology, Duke University, Durham, North Carolina.,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
| | - Huishan Zhu
- Department of Pathology, Duke University, Durham, North Carolina.,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
| | - Paula K Greer
- Department of Pathology, Duke University, Durham, North Carolina.,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
| | - Liwei Zhang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yiping He
- Department of Pathology, Duke University, Durham, North Carolina.,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
| | - Matthew S Waitkus
- Department of Pathology, Duke University, Durham, North Carolina. .,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
| | - Hai Yan
- Department of Pathology, Duke University, Durham, North Carolina. .,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
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36
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Cell Cycle and DNA Repair Regulation in the Damage Response: Protein Phosphatases Take Over the Reins. Int J Mol Sci 2020; 21:ijms21020446. [PMID: 31936707 PMCID: PMC7014277 DOI: 10.3390/ijms21020446] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/29/2019] [Accepted: 01/02/2020] [Indexed: 12/14/2022] Open
Abstract
Cells are constantly suffering genotoxic stresses that affect the integrity of our genetic material. Genotoxic insults must be repaired to avoid the loss or inappropriate transmission of the genetic information, a situation that could lead to the appearance of developmental abnormalities and tumorigenesis. To combat this threat, eukaryotic cells have evolved a set of sophisticated molecular mechanisms that are collectively known as the DNA damage response (DDR). This surveillance system controls several aspects of the cellular response, including the detection of lesions, a temporary cell cycle arrest, and the repair of the broken DNA. While the regulation of the DDR by numerous kinases has been well documented over the last decade, the complex roles of protein dephosphorylation have only recently begun to be investigated. Here, we review recent progress in the characterization of DDR-related protein phosphatases during the response to a DNA lesion, focusing mainly on their ability to modulate the DNA damage checkpoint and the repair of the damaged DNA. We also discuss their protein composition and structure, target specificity, and biochemical regulation along the different stages encompassed in the DDR. The compilation of this information will allow us to better comprehend the physiological significance of protein dephosphorylation in the maintenance of genome integrity and cell viability in response to genotoxic stress.
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37
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Nader CP, Cidem A, Verrills NM, Ammit AJ. Protein phosphatase 2A (PP2A): a key phosphatase in the progression of chronic obstructive pulmonary disease (COPD) to lung cancer. Respir Res 2019; 20:222. [PMID: 31623614 PMCID: PMC6798356 DOI: 10.1186/s12931-019-1192-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 09/20/2019] [Indexed: 02/06/2023] Open
Abstract
Lung cancer (LC) has the highest relative risk of development as a comorbidity of chronic obstructive pulmonary disease (COPD). The molecular mechanisms that mediate chronic inflammation and lung function impairment in COPD have been identified in LC. This suggests the two diseases are more linked than once thought. Emerging data in relation to a key phosphatase, protein phosphatase 2A (PP2A), and its regulatory role in inflammatory and tumour suppression in both disease settings suggests that it may be critical in the progression of COPD to LC. In this review, we uncover the importance of the functional and active PP2A holoenzyme in the context of both diseases. We describe PP2A inactivation via direct and indirect means and explore the actions of two key PP2A endogenous inhibitors, cancerous inhibitor of PP2A (CIP2A) and inhibitor 2 of PP2A (SET), and the role they play in COPD and LC. We explain how dysregulation of PP2A in COPD creates a favourable inflammatory micro-environment and promotes the initiation and progression of tumour pathogenesis. Finally, we highlight PP2A as a druggable target in the treatment of COPD and LC and demonstrate the potential of PP2A re-activation as a strategy to halt COPD disease progression to LC. Although further studies are required to elucidate if PP2A activity in COPD is a causal link for LC progression, studies focused on the potential of PP2A reactivating agents to reduce the risk of LC formation in COPD patients will be pivotal in improving clinical outcomes for both COPD and LC patients in the future.
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Affiliation(s)
- Cassandra P Nader
- Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia
| | - Aylin Cidem
- Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia
| | - Nicole M Verrills
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, 2308, Australia
- Priority Research Centre for Cancer Research, Innovation & Translation, Faculty of Health & Medicine, Hunter Medical Research Institute, New Lambton Heights, NSW, 2305, Australia
| | - Alaina J Ammit
- Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia.
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia.
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38
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Kauko O, O'Connor CM, Kulesskiy E, Sangodkar J, Aakula A, Izadmehr S, Yetukuri L, Yadav B, Padzik A, Laajala TD, Haapaniemi P, Momeny M, Varila T, Ohlmeyer M, Aittokallio T, Wennerberg K, Narla G, Westermarck J. PP2A inhibition is a druggable MEK inhibitor resistance mechanism in KRAS-mutant lung cancer cells. Sci Transl Med 2019; 10:10/450/eaaq1093. [PMID: 30021885 DOI: 10.1126/scitranslmed.aaq1093] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 04/21/2018] [Accepted: 06/08/2018] [Indexed: 12/15/2022]
Abstract
Kinase inhibitor resistance constitutes a major unresolved clinical challenge in cancer. Furthermore, the role of serine/threonine phosphatase deregulation as a potential cause for resistance to kinase inhibitors has not been thoroughly addressed. We characterize protein phosphatase 2A (PP2A) activity as a global determinant of KRAS-mutant lung cancer cell resistance across a library of >200 kinase inhibitors. The results show that PP2A activity modulation alters cancer cell sensitivities to a large number of kinase inhibitors. Specifically, PP2A inhibition ablated mitogen-activated protein kinase kinase (MEK) inhibitor response through the collateral activation of AKT/mammalian target of rapamycin (mTOR) signaling. Combination of mTOR and MEK inhibitors induced cytotoxicity in PP2A-inhibited cells, but even this drug combination could not abrogate MYC up-regulation in PP2A-inhibited cells. Treatment with an orally bioavailable small-molecule activator of PP2A DT-061, in combination with the MEK inhibitor AZD6244, resulted in suppression of both p-AKT and MYC, as well as tumor regression in two KRAS-driven lung cancer mouse models. DT-061 therapy also abrogated MYC-driven tumorigenesis. These data demonstrate that PP2A deregulation drives MEK inhibitor resistance in KRAS-mutant cells. These results emphasize the need for better understanding of phosphatases as key modulators of cancer therapy responses.
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Affiliation(s)
- Otto Kauko
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland.,Institute of Biomedicine, University of Turku, 20520 Turku, Finland.,TuBS and TuDMM Doctoral Programmes, University of Turku, 20520 Turku, Finland
| | - Caitlin M O'Connor
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH 44106-7285, USA
| | - Evgeny Kulesskiy
- Institute for Molecular Medicine Finland, University of Helsinki, 00014 Helsinki, Finland
| | - Jaya Sangodkar
- Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Anna Aakula
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Sudeh Izadmehr
- Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Laxman Yetukuri
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Bhagwan Yadav
- Institute for Molecular Medicine Finland, University of Helsinki, 00014 Helsinki, Finland
| | - Artur Padzik
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Teemu Daniel Laajala
- Institute for Molecular Medicine Finland, University of Helsinki, 00014 Helsinki, Finland.,Department of Mathematics and Statistics, University of Turku, 20520 Turku, Finland
| | - Pekka Haapaniemi
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Majid Momeny
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Taru Varila
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Michael Ohlmeyer
- Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Tero Aittokallio
- Institute for Molecular Medicine Finland, University of Helsinki, 00014 Helsinki, Finland.,Department of Mathematics and Statistics, University of Turku, 20520 Turku, Finland
| | - Krister Wennerberg
- Institute for Molecular Medicine Finland, University of Helsinki, 00014 Helsinki, Finland
| | - Goutham Narla
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH 44106-7285, USA
| | - Jukka Westermarck
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland. .,Institute of Biomedicine, University of Turku, 20520 Turku, Finland
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39
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Sun Z, Li L, Qu J, Li H, Chen H. Proteomic analysis of therapeutic effects of Qingyi pellet on rodent severe acute pancreatitis-associated lung injury. Biomed Pharmacother 2019; 118:109300. [DOI: 10.1016/j.biopha.2019.109300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 07/25/2019] [Accepted: 07/31/2019] [Indexed: 12/13/2022] Open
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40
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PARP Inhibitors in Prostate Cancer—The Preclinical Rationale and Current Clinical Development. Genes (Basel) 2019; 10:genes10080565. [PMID: 31357527 PMCID: PMC6723995 DOI: 10.3390/genes10080565] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 07/22/2019] [Accepted: 07/22/2019] [Indexed: 01/08/2023] Open
Abstract
Prostate cancer is globally the second most commonly diagnosed cancer type in men. Recent studies suggest that mutations in DNA repair genes are associated with aggressive forms of prostate cancer and castration resistance. Prostate cancer with DNA repair defects may be vulnerable to therapeutic targeting by Poly(ADP-ribose) polymerase (PARP) inhibitors. PARP enzymes modify target proteins with ADP-ribose in a process called PARylation and are in particular involved in single strand break repair. The rationale behind the clinical trials that led to the current use of PARP inhibitors to treat cancer was to target the dependence of BRCA-mutant cancer cells on the PARP-associated repair pathway due to deficiency in homologous recombination. However, recent studies have proposed therapeutic potential for PARP inhibitors in tumors with a variety of vulnerabilities generating dependence on PARP beyond the synthetic lethal targeting of BRCA1/BRCA2 mutated tumors, suggesting a wider potential than initially thought. Importantly, PARP-associated DNA repair pathways are also closely connected to androgen receptor (AR) signaling, which is a key regulator of tumor growth and a central therapeutic target in prostate cancer. In this review, we provide an extensive overview of published and ongoing trials exploring PARP inhibitors in treatment of prostate cancer and discuss the underlying biology. Several clinical trials are currently studying PARP inhibitor mono-and combination therapies in the treatment of prostate cancer. Integration of drugs targeting DNA repair pathways in prostate cancer treatment modalities allows developing of more personalized care taking also into account the genetic makeup of individual tumors.
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41
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Bernstock JD, Peruzzotti-Jametti L, Leonardi T, Vicario N, Ye D, Lee YJ, Maric D, Johnson KR, Mou Y, Van Den Bosch A, Winterbone M, Friedman GK, Franklin RJM, Hallenbeck JM, Pluchino S. SUMOylation promotes survival and integration of neural stem cell grafts in ischemic stroke. EBioMedicine 2019; 42:214-224. [PMID: 30905846 PMCID: PMC6491415 DOI: 10.1016/j.ebiom.2019.03.035] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/25/2019] [Accepted: 03/13/2019] [Indexed: 12/29/2022] Open
Abstract
Background Neural stem cell (NSC)-based therapies hold great promise for treating diseases of the central nervous system (CNS). However, several fundamental problems still need to be overcome to fully exploit the clinical potential of NSC therapeutics. Chief among them is the limited survival of NSC grafts within hostile microenvironments. Methods Herein, we sought to engineer NSCs in an effort to increase graft survival within ischemic brain lesions via upregulation of global SUMOylation, a post-translational modification critically involved in mediating tolerance to ischemia/reperfusion. Findings NSCs overexpressing the SUMO E2-conjugase Ubc9 displayed resistance to oxygen-glucose-deprivation/restoration of oxygen/glucose (OGD/ROG) and enhanced neuronal differentiation in vitro, as well as increased survival and neuronal differentiation when transplanted in mice with transient middle cerebral artery occlusion in vivo. Interpretation Our work highlights a critical role for SUMOylation in NSC biology and identifies a biological pathway that can be targeted to increase the effectiveness of exogenous stem cell medicines in ischemic stroke. Fund Intramural Research Program of the NINDS/NIH, the Italian Multiple Sclerosis Foundation (FISM), the Bascule Charitable Trust, NIH-IRTA-OxCam and Wellcome Trust Research Training Fellowships. Ubc9-overexpressing NSCs demonstrate enhanced neuronal differentiation. Upregulating SUMOylation in NSCs increases resistance to ischemia/reperfusion in vitro. Ubc9-overexpressing NSC grafts robustly integrate within the brain of mice post-stroke.
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Affiliation(s)
- Joshua D Bernstock
- Stroke Branch, National Institutes of Health (NINDS/NIH), National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA; Department of Clinical Neurosciences, University of Cambridge, UK.
| | - Luca Peruzzotti-Jametti
- Department of Clinical Neurosciences, University of Cambridge, UK; NIHR Biomedical Research Centre, University of Cambridge, UK.
| | - Tommaso Leonardi
- Department of Clinical Neurosciences, University of Cambridge, UK; NIHR Biomedical Research Centre, University of Cambridge, UK
| | - Nunzio Vicario
- Department of Clinical Neurosciences, University of Cambridge, UK; Department of Biomedical and Biotechnological Sciences, Physiology Section, University of Catania, Italy
| | - Daniel Ye
- Stroke Branch, National Institutes of Health (NINDS/NIH), National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Yang-Ja Lee
- Stroke Branch, National Institutes of Health (NINDS/NIH), National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Dragan Maric
- Flow and Imaging Cytometry Core Facility, National Institutes of Health (NINDS/NIH), National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Kory R Johnson
- Bioinformatics Section, Information Technology & Bioinformatics Program, Division of Intramural Research (DIR), (NINDS/NIH), Bethesda, MD, USA
| | - Yongshan Mou
- Stroke Branch, National Institutes of Health (NINDS/NIH), National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | | | - Mark Winterbone
- Department of Clinical Neurosciences, University of Cambridge, UK
| | - Gregory K Friedman
- Department of Pediatrics and Neurosurgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Robin J M Franklin
- Department of Clinical Neurosciences, University of Cambridge, UK; Wellcome Trust-Medical Research Council Stem Cell Institute, University of Cambridge, UK
| | - John M Hallenbeck
- Stroke Branch, National Institutes of Health (NINDS/NIH), National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA.
| | - Stefano Pluchino
- Department of Clinical Neurosciences, University of Cambridge, UK; NIHR Biomedical Research Centre, University of Cambridge, UK.
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42
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Vriend J, Tate RB. Differential Expression of Genes for Ubiquitin Ligases in Medulloblastoma Subtypes. THE CEREBELLUM 2019; 18:469-488. [PMID: 30810905 DOI: 10.1007/s12311-019-1009-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Using publically available datasets on gene expression in medulloblastoma (MB) subtypes, we selected genes for ubiquitin ligases and identified statistically those that best predicted each of the four major MB subgroups as separate disease entities. We identify a gene coding for an ubiquitin ligase, ZNRF3, whose overexpression alone can predict the WNT subgroup for 100% in the Pfister dataset. For the SHH subgroup, we identify a gene for a regulatory subunit of the protein phosphatase 2A (PP2A), PPP2R2C, as the major predictor among the E3 ligases genes. The ubiquitin and ubiquitin-like conjugation database (UUCD) lists PPP2R2C as coding for a Cullin Ring ubiquitin ligase adaptor. For group 3 MBs, the best ubiquitin ligase predictor was PPP2R2B, a gene which codes for another regulatory subunit of the PP2A holoenzyme. For group 4, the best E3 gene predictors were MID2, ZBTB18, and PPP2R2A, which codes for a third PP2A regulatory subunit. Heatmap analysis of the E3 gene data shows that expression of ten genes for ubiquitin ligases can be used to classify MBs into the four major consensus subgroups. This was illustrated by analysis of gene expression of ubiquitin ligases of the Pfister dataset and confirmed in the dataset of Cavalli. We conclude that genes for ubiquitin ligases can be used as genetic markers for MB subtypes and that the proteins coded for by these genes should be investigated as subtype specific therapeutic targets for MB.
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Affiliation(s)
- Jerry Vriend
- Department of Human Anatomy & Cell Science, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Rm134, BMSB, 745 Bannatyne Avenue, Winnipeg, Manitoba, R3E 0J9, Canada.
| | - Robert B Tate
- Department of Community Health Sciences, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
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Ramos F, Villoria MT, Alonso-Rodríguez E, Clemente-Blanco A. Role of protein phosphatases PP1, PP2A, PP4 and Cdc14 in the DNA damage response. Cell Stress 2019; 3:70-85. [PMID: 31225502 PMCID: PMC6551743 DOI: 10.15698/cst2019.03.178] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Maintenance of genome integrity is fundamental for cellular physiology. Our hereditary information encoded in the DNA is intrinsically susceptible to suffer variations, mostly due to the constant presence of endogenous and environmental genotoxic stresses. Genomic insults must be repaired to avoid loss or inappropriate transmission of the genetic information, a situation that could lead to the appearance of developmental anomalies and tumorigenesis. To safeguard our genome, cells have evolved a series of mechanisms collectively known as the DNA damage response (DDR). This surveillance system regulates multiple features of the cellular response, including the detection of the lesion, a transient cell cycle arrest and the restoration of the broken DNA molecule. While the role of multiple kinases in the DDR has been well documented over the last years, the intricate roles of protein dephosphorylation have only recently begun to be addressed. In this review, we have compiled recent information about the function of protein phosphatases PP1, PP2A, PP4 and Cdc14 in the DDR, focusing mainly on their capacity to regulate the DNA damage checkpoint and the repair mechanism encompassed in the restoration of a DNA lesion.
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Affiliation(s)
- Facundo Ramos
- Cell Cycle and Genome Stability Group. Institute of Functional Biology and Genomics (IBFG). Spanish National Research Council (CSIC), University of Salamanca (USAL), C/Zacarías González 2, Salamanca 37007, SPAIN
| | - María Teresa Villoria
- Cell Cycle and Genome Stability Group. Institute of Functional Biology and Genomics (IBFG). Spanish National Research Council (CSIC), University of Salamanca (USAL), C/Zacarías González 2, Salamanca 37007, SPAIN
| | - Esmeralda Alonso-Rodríguez
- Cell Cycle and Genome Stability Group. Institute of Functional Biology and Genomics (IBFG). Spanish National Research Council (CSIC), University of Salamanca (USAL), C/Zacarías González 2, Salamanca 37007, SPAIN
| | - Andrés Clemente-Blanco
- Cell Cycle and Genome Stability Group. Institute of Functional Biology and Genomics (IBFG). Spanish National Research Council (CSIC), University of Salamanca (USAL), C/Zacarías González 2, Salamanca 37007, SPAIN
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44
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Raman D, Pervaiz S. Redox inhibition of protein phosphatase PP2A: Potential implications in oncogenesis and its progression. Redox Biol 2019; 27:101105. [PMID: 30686777 PMCID: PMC6859563 DOI: 10.1016/j.redox.2019.101105] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 01/04/2019] [Accepted: 01/09/2019] [Indexed: 01/17/2023] Open
Abstract
Cellular processes are dictated by the active signaling of proteins relaying messages to regulate cell proliferation, apoptosis, signal transduction and cell communications. An intricate web of protein kinases and phosphatases are critical to the proper transmission of signals across such cascades. By governing 30–50% of all protein dephosphorylation in the cell, with prominent substrate proteins being key regulators of signaling cascades, the phosphatase PP2A has emerged as a celebrated player in various developmental and tumorigenic pathways, thereby posing as an attractive target for therapeutic intervention in various pathologies wherein its activity is deregulated. This review is mainly focused on refreshing our understanding of the structural and functional complexity that cocoons the PP2A phosphatase, and its expression in cancers. Additionally, we focus on its physiological regulation as well as into recent advents and strategies that have shown promise in countering the deregulation of the phosphatase through its targeted reactivation. Finally, we dwell upon one of the key regulators of PP2A in cancer cells-cellular redox status-its multifarious nature, and its integration into the reactome of PP2A, highlighting some of the significant impacts that ROS can inflict on the structural modifications and functional aspect of PP2A.
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Affiliation(s)
- Deepika Raman
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Shazib Pervaiz
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Medical Science Cluster Cancer Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; National University Cancer Institute, National University Health System, Singapore, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore.
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45
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Parameswaran S, Kundapur D, Vizeacoumar FS, Freywald A, Uppalapati M, Vizeacoumar FJ. A Road Map to Personalizing Targeted Cancer Therapies Using Synthetic Lethality. Trends Cancer 2018; 5:11-29. [PMID: 30616753 DOI: 10.1016/j.trecan.2018.11.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 10/28/2018] [Accepted: 11/08/2018] [Indexed: 12/12/2022]
Abstract
Targeted therapies rely on the genetic and epigenetic status of the tumor cells and are seen as the most promising approach to treat cancer today. However, current targeted therapies focus on directly inhibiting those molecules that are altered in tumor cells. Unfortunately, targeting these molecules, even with specific inhibitors, is challenging as tumor cells rewire their genetic circuitry to eliminate genetic dependency on these targets. Here, we describe how synthetic lethality approaches can be used to identify genetic dependencies and develop personalized targeted therapies. We also discuss strategies to specifically target these genetic dependencies, using small molecule and biologic drugs.
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Affiliation(s)
- Sreejit Parameswaran
- Department of Pathology and Laboratory Medicine, College of Medicine, University of Saskatchewan, Saskatoon, S7N 5E5, Canada; These authors contributed equally
| | - Deeksha Kundapur
- Department of Pathology and Laboratory Medicine, College of Medicine, University of Saskatchewan, Saskatoon, S7N 5E5, Canada; These authors contributed equally
| | - Frederick S Vizeacoumar
- Department of Pathology and Laboratory Medicine, College of Medicine, University of Saskatchewan, Saskatoon, S7N 5E5, Canada
| | - Andrew Freywald
- Department of Pathology and Laboratory Medicine, College of Medicine, University of Saskatchewan, Saskatoon, S7N 5E5, Canada.
| | - Maruti Uppalapati
- Department of Pathology and Laboratory Medicine, College of Medicine, University of Saskatchewan, Saskatoon, S7N 5E5, Canada.
| | - Franco J Vizeacoumar
- Department of Pathology and Laboratory Medicine, College of Medicine, University of Saskatchewan, Saskatoon, S7N 5E5, Canada; Cancer Research, Saskatchewan Cancer Agency, 107 Wiggins Road, Saskatoon, S7N 5E5, Canada.
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46
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Marzec K, Burgess A. The Oncogenic Functions of MASTL Kinase. Front Cell Dev Biol 2018; 6:162. [PMID: 30555827 PMCID: PMC6282046 DOI: 10.3389/fcell.2018.00162] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 11/08/2018] [Indexed: 01/14/2023] Open
Abstract
MASTL kinase is a master regulator of mitosis, essential for ensuring that mitotic substrate phosphorylation is correctly maintained. It achieves this through the phosphorylation of alpha-endosulfine and subsequent inhibition of the tumor suppressor PP2A-B55 phosphatase. In recent years MASTL has also emerged as a novel oncogenic kinase that is upregulated in a number of cancer types, correlating with chromosome instability and poor patient survival. While the chromosome instability is likely directly linked to MASTL's control of mitotic phosphorylation, several new studies indicated that MASTL has additional effects outside of mitosis and beyond regulation of PP2A-B55. These include control of normal DNA replication timing, and regulation of AKT/mTOR and Wnt/β-catenin oncogenic kinase signaling. In this review, we will examine the phenotypes and mechanisms for how MASTL, ENSA, and PP2A-B55 deregulation drives tumor progression and metastasis. Finally, we will explore the rationale for the future development of MASTL inhibitors as new cancer therapeutics.
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Affiliation(s)
- Kamila Marzec
- ANZAC Research Institute, University of Sydney, Sydney, NSW, Australia
| | - Andrew Burgess
- ANZAC Research Institute, University of Sydney, Sydney, NSW, Australia.,Faculty of Medicine and Health, Concord Clinical School, University of Sydney, Sydney, NSW, Australia
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Mazhar S, Taylor SE, Sangodkar J, Narla G. Targeting PP2A in cancer: Combination therapies. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:51-63. [PMID: 30401535 DOI: 10.1016/j.bbamcr.2018.08.020] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 08/21/2018] [Accepted: 08/28/2018] [Indexed: 12/12/2022]
Abstract
The serine/threonine phosphatase PP2A regulates a vast portion of the phosphoproteome including pathways involved in apoptosis, proliferation and DNA damage response and PP2A inactivation is a vital step in malignant transformation. Many groups have explored the therapeutic venue of combining PP2A reactivation with kinase inhibition to counteract the very changes in tumor suppressors and oncogenes that lead to cancer development. Conversely, inhibition of PP2A to complement chemotherapy and radiation-induced cancer cell death is also an area of active investigation. Here we review the studies that utilize PP2A targeted agents as combination therapy in cancer. A potential role for PP2A in tumor immunity is also highlighted.
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Affiliation(s)
- Sahar Mazhar
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Sarah E Taylor
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Jaya Sangodkar
- Division of Genetic Medicine, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Goutham Narla
- Division of Genetic Medicine, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA.
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48
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Fleury H, Carmona E, Morin VG, Meunier L, Masson JY, Tonin PN, Provencher D, Mes-Masson AM. Cumulative defects in DNA repair pathways drive the PARP inhibitor response in high-grade serous epithelial ovarian cancer cell lines. Oncotarget 2018; 8:40152-40168. [PMID: 27374179 PMCID: PMC5522225 DOI: 10.18632/oncotarget.10308] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 06/09/2016] [Indexed: 01/17/2023] Open
Abstract
PARP inhibitors (PARPi), such as Olaparib, have shown promising results in high-grade serous (HGS) epithelial ovarian cancer (EOC) treatment. PARPi sensitivity has been mainly associated with homologous recombination (HR) deficiency, but clinical trials have shown that predicting actual patient response is complex. Here, we investigated gene expression microarray, HR functionality and Olaparib sensitivity of 18 different HGS EOC cell lines and demonstrate that PARPi sensitivity is not only associated with HR defects. Gene target validation show that down regulation of genes in the nucleotide excision repair (NER) and mismatch repair (MMR) pathways (ERCC8 and MLH1, respectively) increases PARPi response. The highest sensitivity was observed when genes in both the HR and either NER or MMR pathways were concomitantly down regulated. Using clinical samples, patients with these concurrent down regulations could be identified. Based on these results, a novel model to predict PARPi sensitivity is herein proposed. This model implies that the extreme responders identified in clinical trials have deficiencies in HR and either NER or MMR.
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Affiliation(s)
- Hubert Fleury
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Canada.,Institut du cancer de Montréal, Montreal, Canada
| | - Euridice Carmona
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Canada.,Institut du cancer de Montréal, Montreal, Canada
| | - Vincent G Morin
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Canada.,Institut du cancer de Montréal, Montreal, Canada
| | - Liliane Meunier
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Canada.,Institut du cancer de Montréal, Montreal, Canada
| | - Jean-Yves Masson
- Genome Stability Laboratory, CHU Research Center, Québec City, Canada.,Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Québec City, Canada
| | - Patricia N Tonin
- Cancer Research Program (CRP), The Research Institute of the McGill University Health Centre, Montreal, Canada.,Department of Human Genetics, McGill University, Montreal, Canada.,Department of Medicine, McGill University, Montreal, Canada
| | - Diane Provencher
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Canada.,Institut du cancer de Montréal, Montreal, Canada.,Division of Gynecologic Oncology, Université de Montréal, Montreal, Canada
| | - Anne-Marie Mes-Masson
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Canada.,Institut du cancer de Montréal, Montreal, Canada.,Department of Medicine, Université de Montréal, Montreal, Canada
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49
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Jordan VK, Fregeau B, Ge X, Giordano J, Wapner RJ, Balci TB, Carter MT, Bernat JA, Moccia AN, Srivastava A, Martin DM, Bielas SL, Pappas J, Svoboda MD, Rio M, Boddaert N, Cantagrel V, Lewis AM, Scaglia F, Kohler JN, Bernstein JA, Dries AM, Rosenfeld JA, DeFilippo C, Thorson W, Yang Y, Sherr EH, Bi W, Scott DA. Genotype-phenotype correlations in individuals with pathogenic RERE variants. Hum Mutat 2018; 39:666-675. [PMID: 29330883 PMCID: PMC5903952 DOI: 10.1002/humu.23400] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 12/28/2017] [Accepted: 01/02/2018] [Indexed: 12/21/2022]
Abstract
Heterozygous variants in the arginine-glutamic acid dipeptide repeats gene (RERE) have been shown to cause neurodevelopmental disorder with or without anomalies of the brain, eye, or heart (NEDBEH). Here, we report nine individuals with NEDBEH who carry partial deletions or deleterious sequence variants in RERE. These variants were found to be de novo in all cases in which parental samples were available. An analysis of data from individuals with NEDBEH suggests that point mutations affecting the Atrophin-1 domain of RERE are associated with an increased risk of structural eye defects, congenital heart defects, renal anomalies, and sensorineural hearing loss when compared with loss-of-function variants that are likely to lead to haploinsufficiency. A high percentage of RERE pathogenic variants affect a histidine-rich region in the Atrophin-1 domain. We have also identified a recurrent two-amino-acid duplication in this region that is associated with the development of a CHARGE syndrome-like phenotype. We conclude that mutations affecting RERE result in a spectrum of clinical phenotypes. Genotype-phenotype correlations exist and can be used to guide medical decision making. Consideration should also be given to screening for RERE variants in individuals who fulfill diagnostic criteria for CHARGE syndrome but do not carry pathogenic variants in CHD7.
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Affiliation(s)
- Valerie K. Jordan
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas
| | - Brieana Fregeau
- Department of Neurology, University of California, San Francisco, San Francisco, California
| | - Xiaoyan Ge
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Baylor Genetics, Houston, Texas
| | - Jessica Giordano
- Institute of Genomic Medicine and Department of OB/GYN, Columbia University Medical Center, New York, New York
| | - Ronald J. Wapner
- Institute of Genomic Medicine and Department of OB/GYN, Columbia University Medical Center, New York, New York
| | - Tugce B. Balci
- Department of Genetics, Children’s Hospital of Eastern Ontario, Ottawa, ON, Canada
| | - Melissa T. Carter
- Department of Genetics, Children’s Hospital of Eastern Ontario, Ottawa, ON, Canada
| | - John A. Bernat
- Stead Family Department of Pediatrics, The University of Iowa, Iowa City, Iowa
| | - Amanda N. Moccia
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan
| | - Anshika Srivastava
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan
| | - Donna M. Martin
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, Michigan
| | - Stephanie L. Bielas
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan
| | - John Pappas
- New York University School of Medicine, New York, New York
| | - Melissa D. Svoboda
- Department of Pediatrics, Children’s Hospital of San Antonio/Baylor College of Medicine, San Antonio, Texas
| | - Marlène Rio
- Laboratory of Developmental Brain Disorders, INSERM UMR 1163, Paris, France
- Service de Génétique, Necker Enfants Malades University Hospital, APHP, Paris, France
| | - Nathalie Boddaert
- Laboratory of Developmental Brain Disorders, INSERM UMR 1163, Paris, France
- Pediatric Radiology, Necker Enfants Malades University Hospital, APHP, Paris, France
| | - Vincent Cantagrel
- Laboratory of Developmental Brain Disorders, INSERM UMR 1163, Paris, France
- Paris Descartes - Sorbonne Paris Cité UniversityImagine Institute, Paris, France
| | - Andrea M. Lewis
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Texas Children’s Hospital, Houston, Texas
| | - Fernando Scaglia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Texas Children’s Hospital, Houston, Texas
| | | | | | | | - Annika M. Dries
- Stanford University School of Medicine, Stanford, California
| | - Jill A. Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Colette DeFilippo
- Stanford Children’s Health/Lucile Packard Children’s Hospital Stanford, Palo Alto, California
| | - Willa Thorson
- University of MiamiMiller School of Medicine, Miami, Florida
| | - Yaping Yang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Baylor Genetics, Houston, Texas
| | - Elliott H. Sherr
- Department of Neurology, University of California, San Francisco, San Francisco, California
| | - Weimin Bi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Baylor Genetics, Houston, Texas
| | - Daryl A. Scott
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Texas Children’s Hospital, Houston, Texas
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50
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Koutsioumpa M, Chen HW, O'Brien N, Koinis F, Mahurkar-Joshi S, Vorvis C, Soroosh A, Luo T, Issakhanian S, Pantuck AJ, Georgoulias V, Iliopoulos D, Slamon DJ, Drakaki A. MKAD-21 Suppresses the Oncogenic Activity of the miR-21/PPP2R2A/ERK Molecular Network in Bladder Cancer. Mol Cancer Ther 2018; 17:1430-1440. [PMID: 29703843 DOI: 10.1158/1535-7163.mct-17-1049] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Revised: 02/20/2018] [Accepted: 04/16/2018] [Indexed: 11/16/2022]
Abstract
Bladder cancer represents a disease associated with significant morbidity and mortality. MiR-21 has been found to have oncogenic activity in multiple cancers, including bladder cancer, whereas inhibition of its expression suppresses tumor growth. Here, we examine the molecular network regulated by miR-21 in bladder cancer and evaluate the effects of i.v. and i.p. administration of a novel miR-21 chemical inhibitor in vivo LNA miR-21 reduced the oncogenic potential of bladder cancer cells, whereas the MKAD-21 chemically modified antisense oligo against miR-21 dose-dependently blocked xenograft growth. I.v. administration of LNA miR-21 was more effective in suppressing tumor growth than was i.p. administration. Integration of computational and transcriptomic analyses in a panel of 28 bladder cancer lines revealed a 15-gene signature that correlates with miR-21 levels. Protein Phosphatase 2 Regulatory Subunit Balpha (PPP2R2A) was one of these 15 genes and was experimentally validated as a novel miR-21 direct target gene. Gene network and molecular analyses showed that PPP2R2A is a potent negative regulator of the ERK pathway activation and bladder cancer cell proliferation. Importantly, we show that PPP2R2A acts as a mediator of miR-21-induced oncogenic effects in bladder cancer. Integrative analysis of human bladder cancer tumors and a large panel of human bladder cancer cell lines revealed a novel 15-gene signature that correlates with miR-21 levels. Importantly, we provide evidence that PPP2R2A represents a new miR-21 direct target and regulator of the ERK pathway and bladder cancer cell growth. Furthermore, i.v. administration of the MKAD-21 inhibitor effectively suppressed tumor growth through regulation of the PPP2R2A-ERK network in mice. Mol Cancer Ther; 17(7); 1430-40. ©2018 AACR.
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Affiliation(s)
- Marina Koutsioumpa
- Center for Systems Biomedicine, Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine, UCLA, Los Angeles, California
| | - Hsiao-Wang Chen
- Division of Hematology-Oncology, Department of Medicine, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, UCLA, Los Angeles, California
| | - Neil O'Brien
- Division of Hematology-Oncology, Department of Medicine, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, UCLA, Los Angeles, California
| | - Filippos Koinis
- Laboratory of Tumor Cell Biology and Department of Medical Oncology, School of Medicine, University of Crete, Heraklion, Greece
| | - Swapna Mahurkar-Joshi
- Center for Systems Biomedicine, Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine, UCLA, Los Angeles, California
| | - Christina Vorvis
- Center for Systems Biomedicine, Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine, UCLA, Los Angeles, California
| | - Artin Soroosh
- Center for Systems Biomedicine, Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine, UCLA, Los Angeles, California
| | - Tong Luo
- Division of Hematology-Oncology, Department of Medicine, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, UCLA, Los Angeles, California
| | - Shawnt Issakhanian
- Division of Hematology-Oncology, Department of Medicine, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, UCLA, Los Angeles, California
| | - Allan J Pantuck
- Department of Urology, Institute of Urologic Oncology, David Geffen School of Medicine, UCLA, Los Angeles, California
| | - Vassilis Georgoulias
- Laboratory of Tumor Cell Biology and Department of Medical Oncology, School of Medicine, University of Crete, Heraklion, Greece
| | - Dimitrios Iliopoulos
- Center for Systems Biomedicine, Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine, UCLA, Los Angeles, California
| | - Dennis J Slamon
- Division of Hematology-Oncology, Department of Medicine, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, UCLA, Los Angeles, California
| | - Alexandra Drakaki
- Division of Hematology-Oncology, Department of Medicine, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, UCLA, Los Angeles, California.
- Department of Urology, Institute of Urologic Oncology, David Geffen School of Medicine, UCLA, Los Angeles, California
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