1
|
Krasniqi E, Ercolani C, Di Benedetto A, Di Lisa FS, Filomeno L, Arcuri T, Botti C, Pelle F, Cavicchi F, Cappelli S, Barba M, Pizzuti L, Maugeri-Saccà M, Moscetti L, Grassadonia A, Tinari N, Sanguineti G, Takanen S, Fragnito D, Terrenato I, Buglioni S, Perracchio L, Latorre A, De Maria R, Pallocca M, Ciliberto G, Giotta F, Vici P. DNA Damage Response in Early Breast Cancer: A Phase III Cohort in the Phobos Study. Cancers (Basel) 2024; 16:2628. [PMID: 39123356 PMCID: PMC11311544 DOI: 10.3390/cancers16152628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2024] [Revised: 07/16/2024] [Accepted: 07/19/2024] [Indexed: 08/12/2024] Open
Abstract
We assessed the impact of DNA damage response and repair (DDR) biomarker expressions in 222 node-positive early breast cancer (BC) patients from a previous Phase III GOIM 9902 trial of adjuvant taxanes. At a median follow-up of 64 months, the original study showed no disease-free survival (DFS) or overall survival (OS) differences with the addition of docetaxel (D) to epirubicine-cyclophosphamide (EC). Immunohistochemistry was employed to assess the expression of DDR phosphoproteins (pATM, pATR, pCHK1, γH2AX, pRPA32, and pWEE1) in tumor tissue, and their association with clinical outcomes was evaluated through the Cox elastic net model. Over an extended follow-up of 234 months, we confirmed no significant differences in DFS or OS between patients treated with EC and those receiving D → EC. A DDR risk score, inversely driven by ATM and ATR expression, emerged as an independent prognostic factor for both DFS (HR = 0.41, p < 0.0001) and OS (HR = 0.61, p = 0.046). Further validation in a public adjuvant BC cohort was possible only for ATM, confirming its protective role. Overall, our findings confirm the potential role of the DDR pathway in BC prognostication and in shaping treatment strategies advocating for an integrated approach, combining molecular markers with clinical-pathological factors.
Collapse
Affiliation(s)
- Eriseld Krasniqi
- Phase IV Clinical Studies Unit, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy; (E.K.); (F.S.D.L.); (T.A.); (P.V.)
| | - Cristiana Ercolani
- Pathology Department, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy; (C.E.); (A.D.B.); (S.B.); (L.P.)
| | - Anna Di Benedetto
- Pathology Department, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy; (C.E.); (A.D.B.); (S.B.); (L.P.)
| | - Francesca Sofia Di Lisa
- Phase IV Clinical Studies Unit, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy; (E.K.); (F.S.D.L.); (T.A.); (P.V.)
| | - Lorena Filomeno
- Phase IV Clinical Studies Unit, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy; (E.K.); (F.S.D.L.); (T.A.); (P.V.)
| | - Teresa Arcuri
- Phase IV Clinical Studies Unit, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy; (E.K.); (F.S.D.L.); (T.A.); (P.V.)
- Department of Radiological, Oncological and Anatomo-Pathological Sciences, Sapienza University of Rome, 00185 Rome, Italy
| | - Claudio Botti
- Breast Surgery Department, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy; (C.B.); (F.P.); (F.C.); (S.C.)
| | - Fabio Pelle
- Breast Surgery Department, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy; (C.B.); (F.P.); (F.C.); (S.C.)
| | - Flavia Cavicchi
- Breast Surgery Department, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy; (C.B.); (F.P.); (F.C.); (S.C.)
| | - Sonia Cappelli
- Breast Surgery Department, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy; (C.B.); (F.P.); (F.C.); (S.C.)
| | - Maddalena Barba
- Division of Medical Oncology 1, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy; (M.B.); (L.P.)
| | - Laura Pizzuti
- Division of Medical Oncology 1, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy; (M.B.); (L.P.)
| | - Marcello Maugeri-Saccà
- Clinical Trial Center, Biostatistics and Bioinformatics Unit, Department of Research, Diagnosis and Innovative Technologies, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy; (M.M.-S.); (I.T.)
- Division of Medical Oncology 2, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy
| | - Luca Moscetti
- Oncology and Hemathology Department, Azienda Ospedaliero-Universitaria Policlinico di Modena, 41125 Modena, Italy;
| | - Antonino Grassadonia
- Department of Innovative Technologies in Medicine and Dentistry, Center for Advanced Studies and Technology (CAST), G. D’Annunzio University Chieti-Pescara, 66100 Chieti, Italy;
| | - Nicola Tinari
- Department of Medical, Oral and Biotechnological Sciences, Center for Advanced Studies and Technology (CAST), G. D’Annunzio University Chieti-Pescara, 66100 Chieti, Italy;
| | - Giuseppe Sanguineti
- Department of Radiation Oncology, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy; (G.S.); (S.T.)
| | - Silvia Takanen
- Department of Radiation Oncology, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy; (G.S.); (S.T.)
| | - Davide Fragnito
- Institute of Endocrinology and Experimental Oncology “G Salvatore”, National Research Council (CNR), 00186 Naples, Italy;
| | - Irene Terrenato
- Clinical Trial Center, Biostatistics and Bioinformatics Unit, Department of Research, Diagnosis and Innovative Technologies, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy; (M.M.-S.); (I.T.)
| | - Simonetta Buglioni
- Pathology Department, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy; (C.E.); (A.D.B.); (S.B.); (L.P.)
| | - Letizia Perracchio
- Pathology Department, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy; (C.E.); (A.D.B.); (S.B.); (L.P.)
| | - Agnese Latorre
- Medical Oncology, IRCCS Istituto Tumori “Giovanni Paolo II”, 70124 Bari, Italy; (A.L.); (F.G.)
| | - Ruggero De Maria
- Department of Translational Medicine and Surgery, Catholic University of the Sacred Hearth, 00153 Rome, Italy;
- IRCCS Fondazione Policlinico Universitario “A Gemelli”, 00168 Rome, Italy
| | - Matteo Pallocca
- Institute of Endocrinology and Experimental Oncology “G Salvatore”, National Research Council (CNR), 00186 Naples, Italy;
| | - Gennaro Ciliberto
- Scientific Direction, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy;
| | - Francesco Giotta
- Medical Oncology, IRCCS Istituto Tumori “Giovanni Paolo II”, 70124 Bari, Italy; (A.L.); (F.G.)
| | - Patrizia Vici
- Phase IV Clinical Studies Unit, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy; (E.K.); (F.S.D.L.); (T.A.); (P.V.)
| |
Collapse
|
2
|
Fousek-Schuller VJ, Borgstahl GEO. The Intriguing Mystery of RPA Phosphorylation in DNA Double-Strand Break Repair. Genes (Basel) 2024; 15:167. [PMID: 38397158 PMCID: PMC10888239 DOI: 10.3390/genes15020167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 01/23/2024] [Accepted: 01/25/2024] [Indexed: 02/25/2024] Open
Abstract
Human Replication Protein A (RPA) was historically discovered as one of the six components needed to reconstitute simian virus 40 DNA replication from purified components. RPA is now known to be involved in all DNA metabolism pathways that involve single-stranded DNA (ssDNA). Heterotrimeric RPA comprises several domains connected by flexible linkers and is heavily regulated by post-translational modifications (PTMs). The structure of RPA has been challenging to obtain. Various structural methods have been applied, but a complete understanding of RPA's flexible structure, its function, and how it is regulated by PTMs has yet to be obtained. This review will summarize recent literature concerning how RPA is phosphorylated in the cell cycle, the structural analysis of RPA, DNA and protein interactions involving RPA, and how PTMs regulate RPA activity and complex formation in double-strand break repair. There are many holes in our understanding of this research area. We will conclude with perspectives for future research on how RPA PTMs control double-strand break repair in the cell cycle.
Collapse
Affiliation(s)
| | - Gloria E. O. Borgstahl
- Eppley Institute for Research in Cancer & Allied Diseases, UNMC, Omaha, NE 68198-6805, USA
| |
Collapse
|
3
|
Qin S, Kitty I, Hao Y, Zhao F, Kim W. Maintaining Genome Integrity: Protein Kinases and Phosphatases Orchestrate the Balancing Act of DNA Double-Strand Breaks Repair in Cancer. Int J Mol Sci 2023; 24:10212. [PMID: 37373360 DOI: 10.3390/ijms241210212] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 06/29/2023] Open
Abstract
DNA double-strand breaks (DSBs) are the most lethal DNA damages which lead to severe genome instability. Phosphorylation is one of the most important protein post-translation modifications involved in DSBs repair regulation. Kinases and phosphatases play coordinating roles in DSB repair by phosphorylating and dephosphorylating various proteins. Recent research has shed light on the importance of maintaining a balance between kinase and phosphatase activities in DSB repair. The interplay between kinases and phosphatases plays an important role in regulating DNA-repair processes, and alterations in their activity can lead to genomic instability and disease. Therefore, study on the function of kinases and phosphatases in DSBs repair is essential for understanding their roles in cancer development and therapeutics. In this review, we summarize the current knowledge of kinases and phosphatases in DSBs repair regulation and highlight the advancements in the development of cancer therapies targeting kinases or phosphatases in DSBs repair pathways. In conclusion, understanding the balance of kinase and phosphatase activities in DSBs repair provides opportunities for the development of novel cancer therapeutics.
Collapse
Affiliation(s)
- Sisi Qin
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Ichiwa Kitty
- Department of Integrated Biomedical Science, Soonchunhyang Institute of Medi-Bio Science (SIMS), Soonchunhyang University, Cheonan 31151, Chungcheongnam-do, Republic of Korea
| | - Yalan Hao
- Analytical Instrumentation Center, Hunan University, Changsha 410082, China
| | - Fei Zhao
- College of Biology, Hunan University, Changsha 410082, China
| | - Wootae Kim
- Department of Integrated Biomedical Science, Soonchunhyang Institute of Medi-Bio Science (SIMS), Soonchunhyang University, Cheonan 31151, Chungcheongnam-do, Republic of Korea
| |
Collapse
|
4
|
TurboID Screening of the OmpP2 Protein Reveals Host Proteins Involved in Recognition and Phagocytosis of Glaesserella parasuis by iPAM Cells. Microbiol Spectr 2022; 10:e0230722. [PMID: 36094311 PMCID: PMC9603499 DOI: 10.1128/spectrum.02307-22] [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] [Indexed: 01/04/2023] Open
Abstract
Glaesserella parasuis is a common bacterium in the porcine upper respiratory tract that causes severe Glasser's disease, which is characterized by polyarthritis, meningitis, and fibrinous polyserositis. TurboID is an enzyme that mediates the biotinylation of endogenous proteins that can fuse with proteins of interest to label protein interactors and local proteomes. To reveal the host proteins that interact with outer membrane protein P2 (OmpP2) by TurboID-mediated proximity labeling in immortalized porcine alveolar macrophage iPAM cells, 0.1 and 2.58 mg/mL His-tagged TurboID-OmpP2 and TurboID recombinant proteins were expressed and purified. By mass spectrometry, we identified 948 and 758 iPAM cell proteins that interacted with His-TurboID-OmpP2 and His-TurboID, respectively. After removal of background proteins through comparison with the TurboID-treated group, 240 unique interacting proteins were identified in the TurboID-OmpP2-treated group. Ultimately, only four membrane proteins were identified, CAV1, ARF6, PPP2R1A, and AP2M1, from these 240 host proteins. Our data indicated that CAV1, ARF6, and PPP2R1A could interact with OmpP2 of G. parasuis, as confirmed by coimmunoprecipitation assay. Finally, we found that CAV1, ARF6, and PPP2R1A were involved in the recognition and phagocytosis of G. parasuis serotype 5 by iPAM cells by using overexpression and RNA interference assays. This study provides first-hand information regarding the interaction of the iPAM cell proteomes with G. parasuis OmpP2 protein by using the TurboID proximity labeling system and identifies three novel host membrane proteins involved in the recognition and phagocytosis of G. parasuis by iPAM cells. These results provide new insight for a better understanding of Glasser's disease pathogenesis. IMPORTANCE G. parasuis can cause serious Glasser's disease, which is characterized by polyarthritis, meningitis, and fibrinous polyserositis in pigs. It can cause high morbidity and mortality in swine herds and major economic losses to the global pig industry. Understanding the mechanism of interactions between alveolar macrophages and pathogenic G. parasuis is essential for developing effective vaccines and targeted drugs against G. parasuis. To reveal the host proteins interacting with OmpP2 by TurboID-mediated proximity labeling in immortalized porcine alveolar macrophage (iPAM) cells, we identified 240 unique proteins from iPAM cells that could interact with G. parasuis OmpP2. Among them, only four membrane proteins, CAV1, ARF6, PPP2R1A, and AP2M1, were identified, and further study showed that CAV1, ARF6, and PPP2R1A are involved in the recognition and phagocytosis of G. parasuis serotype 5 by iPAM cells. This study provides new insight into proteomic interactions between hosts and pathogenic microorganisms.
Collapse
|
5
|
Kashani E, Vassella E. Pleiotropy of PP2A Phosphatases in Cancer with a Focus on Glioblastoma IDH Wildtype. Cancers (Basel) 2022; 14:5227. [PMID: 36358647 PMCID: PMC9654311 DOI: 10.3390/cancers14215227] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 10/13/2022] [Accepted: 10/20/2022] [Indexed: 07/29/2023] Open
Abstract
Serine/Threonine protein phosphatase 2A (PP2A) is a heterotrimeric (or occasionally, heterodimeric) phosphatase with pleiotropic functions and ubiquitous expression. Despite the fact that they all contribute to protein dephosphorylation, multiple PP2A complexes exist which differ considerably by their subcellular localization and their substrate specificity, suggesting diverse PP2A functions. PP2A complex formation is tightly regulated by means of gene expression regulation by transcription factors, microRNAs, and post-translational modifications. Furthermore, a constant competition between PP2A regulatory subunits is taking place dynamically and depending on the spatiotemporal circumstance; many of the integral subunits can outcompete the rest, subjecting them to proteolysis. PP2A modulation is especially important in the context of brain tumors due to its ability to modulate distinct glioma-promoting signal transduction pathways, such as PI3K/Akt, Wnt, Ras, NF-κb, etc. Furthermore, PP2A is also implicated in DNA repair and survival pathways that are activated upon treatment of glioma cells with chemo-radiation. Depending on the cancer cell type, preclinical studies have shown some promise in utilising PP2A activator or PP2A inhibitors to overcome therapy resistance. This review has a special focus on "glioblastoma, IDH wild-type" (GBM) tumors, for which the therapy options have limited efficacy, and tumor relapse is inevitable.
Collapse
Affiliation(s)
- Elham Kashani
- Institute of Pathology, University of Bern, 3008 Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Erik Vassella
- Institute of Pathology, University of Bern, 3008 Bern, Switzerland
| |
Collapse
|
6
|
Casado-Combreras MÁ, Rivero-Rodríguez F, Elena-Real CA, Molodenskiy D, Díaz-Quintana A, Martinho M, Gerbaud G, González-Arzola K, Velázquez-Campoy A, Svergun D, Belle V, De la Rosa MA, Díaz-Moreno I. PP2A is activated by cytochrome c upon formation of a diffuse encounter complex with SET/TAF-Iβ. Comput Struct Biotechnol J 2022; 20:3695-3707. [PMID: 35891793 PMCID: PMC9293736 DOI: 10.1016/j.csbj.2022.07.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 07/04/2022] [Accepted: 07/04/2022] [Indexed: 11/25/2022] Open
Abstract
Intrinsic protein flexibility is of overwhelming relevance for intermolecular recognition and adaptability of highly dynamic ensemble of complexes, and the phenomenon is essential for the understanding of numerous biological processes. These conformational ensembles-encounter complexes-lack a unique organization, which prevents the determination of well-defined high resolution structures. This is the case for complexes involving the oncoprotein SET/template-activating factor-Iβ (SET/TAF-Iβ), a histone chaperone whose functions and interactions are significantly affected by its intrinsic structural plasticity. Besides its role in chromatin remodeling, SET/TAF-Iβ is an inhibitor of protein phosphatase 2A (PP2A), which is a key phosphatase counteracting transcription and signaling events controlling the activity of DNA damage response (DDR) mediators. During DDR, SET/TAF-Iβ is sequestered by cytochrome c (Cc) upon migration of the hemeprotein from mitochondria to the cell nucleus. Here, we report that the nuclear SET/TAF-Iβ:Cc polyconformational ensemble is able to activate PP2A. In particular, the N-end folded, globular region of SET/TAF-Iβ (a.k.a. SET/TAF-Iβ ΔC)-which exhibits an unexpected, intrinsically highly dynamic behavior-is sufficient to be recognized by Cc in a diffuse encounter manner. Cc-mediated blocking of PP2A inhibition is deciphered using an integrated structural and computational approach, combining small-angle X-ray scattering, electron paramagnetic resonance, nuclear magnetic resonance, calorimetry and molecular dynamics simulations.
Collapse
Key Words
- ANP32B, Acidic leucine-rich nuclear phosphoprotein family member B
- BTFA, 3-bromo-1,1,1-trifluoroacetone
- CD, Circular dichroism
- CDK9, Cyclin-dependent kinase 9
- CW, Continuous wave
- Cc, Cytochrome c
- Cytochrome c
- DDR, DNA damage response
- DEER, Double electron–electron resonance
- DLS, Dynamic light scattering
- DMEM, Dulbecco’s modified Eagle’s medium
- DNA, Deoxyribonucleic acid
- DTT, Dithiotreitol
- Dmax, Maximum dimension
- EDTA, Ethylenediamine tetraacetic acid
- EGTA, Ethyleneglycol tetraacetic acid
- EPR, Electron paramagnetic resonance
- Encounter complex
- FBS, Fetal bovine serum
- GUI, Graphical user interface
- HEK, Human embryonic kidney cells
- HRP, Horseradish peroxidase
- I2PP2A, Inhibitor 2 of the protein phosphatase 2A
- I3PP2A, Inhibitor 3 of the protein phosphatase 2A
- INTAC, Integrator-PP2A complex
- IPTG, Isopropyl-β-D-1-thiogalactopyranoside
- ITC, Isothermal titration calorimetry
- Ip/Id, Intensity ratio of NMR resonances between paramagnetic and diamagnetic samples
- LB, Luria-Bertani
- MD, Molecular dynamics
- MTS, (1-acetoxy-2,2,5,5-tetramethyl-δ-3-pyrroline-3-methyl) methanethiosulfonate
- MTSL, (1-oxyl-2,2,5,5-tetramethyl- δ −3-pyrroline-3-methyl) methanethiosulfonate
- MW, Molecular weight
- Molecular dynamics
- NAP1, Nucleosome assembly protein 1
- NAPL, Nucleosome assembly protein L
- NMA, Normal mode analysis
- NMR, Nuclear magnetic resonance
- NPT, Constant number, pressure and temperature
- NVT, Constant number, volume and temperature
- Nuclear magnetic resonance
- OD600, Optical density measured at 600 nm
- OPC, Optimal 3-charge, 4-point rigid water model
- PCR, Polymerase chain reaction
- PME, Particle mesh Ewald
- PMSF, Phenylmethylsulfonyl fluoride
- PP2A, Protein phosphatase 2A
- PRE, Paramagnetic relaxation enhancement
- PVDF, Polyvinylidene fluoride
- Protein phosphatase 2A
- RNA, Ribonucleic acid
- RNApol II, RNA polymerase II
- Rg, Radius of gyration
- SAXS, Small-angle X-ray scattering
- SC, Sample changer
- SDS-PAGE, Sodium dodecylsulfate-polyacrylamide gel electrophoresis
- SDSL, Site-directed spin labeling
- SEC, Size-exclusion chromatography
- SET/TAF-Iβ
- SET/TAF-Iβ ΔC, SET/template-activating factor-Iβ construct lacking its C-terminal domain
- SET/TAF-Iβ, SET/template-activating factor-Iβ
- SPRi, Surface plasmon resonance imaging
- TAF-Iα, Template-activating factor-Iα
- TPBS, Tween 20-phosphate buffered saline
- VPS75, Vacuolar protein sorting-associated protein 75
- WT, Wild type
- XRD, X-ray diffraction
Collapse
Affiliation(s)
- Miguel Á. Casado-Combreras
- Institute for Chemical Research (IIQ), Scientific Research Centre “Isla de la Cartuja” (cicCartuja), University of Seville and CSIC, Avda. Américo Vespucio, 49, 41092 Seville, Spain
| | - Francisco Rivero-Rodríguez
- Institute for Chemical Research (IIQ), Scientific Research Centre “Isla de la Cartuja” (cicCartuja), University of Seville and CSIC, Avda. Américo Vespucio, 49, 41092 Seville, Spain
| | - Carlos A. Elena-Real
- Institute for Chemical Research (IIQ), Scientific Research Centre “Isla de la Cartuja” (cicCartuja), University of Seville and CSIC, Avda. Américo Vespucio, 49, 41092 Seville, Spain
- Centre de Biologie Structurale (CBS), INSERM, Centre National de la Recherche Scientifique (CNRS) and Université de Montpellier. 29 rue de Navacelles, 34090 Montpellier, France
| | - Dmitry Molodenskiy
- European Molecular Biology Laboratory, Hamburg Outstation, c/o Deutsches Elektronen-Synchrotron, Notkestr. 85, 22607 Hamburg, Germany
| | - Antonio Díaz-Quintana
- Institute for Chemical Research (IIQ), Scientific Research Centre “Isla de la Cartuja” (cicCartuja), University of Seville and CSIC, Avda. Américo Vespucio, 49, 41092 Seville, Spain
| | - Marlène Martinho
- Aix Marseille Univ. Centre National de la Recherche Scientifique (CNRS), BIP UMR7281, Bioénergétique et Ingénierie des protéines, 13402 Marseille, France
| | - Guillaume Gerbaud
- Aix Marseille Univ. Centre National de la Recherche Scientifique (CNRS), BIP UMR7281, Bioénergétique et Ingénierie des protéines, 13402 Marseille, France
| | - Katiuska González-Arzola
- Institute for Chemical Research (IIQ), Scientific Research Centre “Isla de la Cartuja” (cicCartuja), University of Seville and CSIC, Avda. Américo Vespucio, 49, 41092 Seville, Spain
| | - Adrián Velázquez-Campoy
- Institute of Biocomputation and Physic of Complex Systems (BIFI), Joint Unit GBsC-CSIC-BIFI, Universidad de Zaragoza. C. de Mariano Esquillor Gómez, Edificio I+D, 50018 Zaragoza, Spain
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, C. Pedro Cerbuna, 12, 50009 Zaragoza, Spain
- Instituto de Investigación Sanitaria de Aragón (IIS Aragon), Zaragoza, Spain
- Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), C. de Melchor Fernández Almagro, 3, 28029 Madrid, Spain
| | - Dmitri Svergun
- European Molecular Biology Laboratory, Hamburg Outstation, c/o Deutsches Elektronen-Synchrotron, Notkestr. 85, 22607 Hamburg, Germany
| | - Valérie Belle
- Aix Marseille Univ. Centre National de la Recherche Scientifique (CNRS), BIP UMR7281, Bioénergétique et Ingénierie des protéines, 13402 Marseille, France
| | - Miguel A. De la Rosa
- Institute for Chemical Research (IIQ), Scientific Research Centre “Isla de la Cartuja” (cicCartuja), University of Seville and CSIC, Avda. Américo Vespucio, 49, 41092 Seville, Spain
| | - Irene Díaz-Moreno
- Institute for Chemical Research (IIQ), Scientific Research Centre “Isla de la Cartuja” (cicCartuja), University of Seville and CSIC, Avda. Américo Vespucio, 49, 41092 Seville, Spain
| |
Collapse
|
7
|
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.
Collapse
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.
| |
Collapse
|
8
|
Sui JD, Tang Z, Chen BPC, Huang P, Yang MQ, Wang NH, Yang HN, Tu HL, Jiang QM, Zhang J, Wang Y, Wu YZ. Protein phosphatase 2A-dependent mitotic hnRNPA1 dephosphorylation and TERRA formation facilitate telomere capping. Mol Cancer Res 2021; 20:583-595. [PMID: 34933911 DOI: 10.1158/1541-7786.mcr-21-0581] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 11/02/2021] [Accepted: 12/09/2021] [Indexed: 11/16/2022]
Affiliation(s)
- Jiang-Dong Sui
- Radiation Oncology Center, Chongqing University Cancer Hospital, Chongqing, China
| | - Zheng Tang
- Radiation Oncology Center, Chongqing University Cancer Hospital, Chongqing, China
| | - Benjamin P C Chen
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Ping Huang
- Radiation Oncology Center, Chongqing University Cancer Hospital, Chongqing, China
| | - Meng-Qi Yang
- College of Bioengineering, Chongqing University, Chongqing, China
| | - Nuo-Han Wang
- School of Medicine, Chongqing University, Chongqing, China
| | - Hao-Nan Yang
- School of Medicine, Chongqing University, Chongqing, China
| | - Hong-Lei Tu
- Radiation Oncology Center, Chongqing University Cancer Hospital, Chongqing, China
| | - Qing-Ming Jiang
- Department of Pathology, Chongqing University Cancer Hospital, Chongqing, China
| | - Jing Zhang
- Department of Pathology, Chongqing University Cancer Hospital, Chongqing, China
| | - Ying Wang
- Radiation Oncology Center, Chongqing University Cancer Hospital, Chongqing, China
| | - Yong-Zhong Wu
- Radiation Oncology Center, Chongqing University Cancer Hospital, Chongqing, China
| |
Collapse
|
9
|
RPA phosphorylation facilitates RAD52 dependent homologous recombination in BRCA-deficient cells. Mol Cell Biol 2021; 42:e0052421. [PMID: 34928169 DOI: 10.1128/mcb.00524-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Loss of RAD52 is synthetically lethal in BRCA-deficient cells, owing to its role in backup homologous recombination (HR) repair of DNA double-strand breaks (DSBs). In HR in mammalian cells, DSBs are processed to single-stranded DNA (ssDNA) overhangs, which are then bound by Replication Protein A(RPA). RPA is exchanged for RAD51 by mediator proteins: in mammals BRCA2 is the primary mediator, however, RAD52 provides an alternative mediator pathway in BRCA-deficient cells. RAD51 stimulates strand exchange between homologous DNA duplexes, a critical step in HR. RPA phosphorylation and de-phosphorylation are important for HR, but its effect on RAD52 mediator function is unknown. Here, we show that RPA phosphorylation is required for RAD52 to salvage HR in BRCA-deficient cells. Using BRCA2-depleted human cells, in which the only available mediator pathway is RAD52-dependent, the expression of phosphorylation-deficient RPA mutant reduced HR. Furthermore, RPA-phospho-mutant cells showed reduced association of RAD52 with RAD51. Interestingly, there was no effect of RPA phosphorylation on RAD52 recruitment to repair foci. Finally, we show that RPA phosphorylation does not affect RAD52-dependent ssDNA annealing. Thus, although RAD52 can be recruited independently of RPA's phosphorylation status, RPA phosphorylation is required for RAD52's association with RAD51, and its subsequent promotion of RAD52-mediated HR.
Collapse
|
10
|
Su B, Lim D, Tian Z, Liu G, Ding C, Cai Z, Chen C, Zhang F, Feng Z. Valproic Acid Regulates HR and Cell Cycle Through MUS81-pRPA2 Pathway in Response to Hydroxyurea. Front Oncol 2021; 11:681278. [PMID: 34513672 PMCID: PMC8429838 DOI: 10.3389/fonc.2021.681278] [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: 03/16/2021] [Accepted: 07/30/2021] [Indexed: 12/24/2022] Open
Abstract
Breast cancer is the primary problem threatening women’s health. The combined application of valproic acid (VPA) and hydroxyurea (HU) has a synergistic effect on killing breast cancer cells, but the molecular mechanism remains elusive. Replication protein A2 phosphorylation (pRPA2), is essential for homologous recombination (HR) repair and cell cycle. Here we showed that in response to HU, the VPA significantly decreased the tumor cells survival, and promoted S-phase slippage, which was associated with the decrease of pCHK1 and WEE1/pCDK1-mediated checkpoint kinases phosphorylation pathway and inhibited pRPA2/Rad51-mediated HR repair pathway; the mutation of pRPA2 significantly diminished the above effect, indicating that VPA-caused HU sensitization was pRPA2 dependent. It was further found that VPA and HU combination treatment also resulted in the decrease of endonuclease MUS81. After MUS81 elimination, not only the level of pRPA2 was abolished in response to HU treatment, but also VPA-caused HU sensitization was significantly down-regulated through pRPA2-mediated checkpoint kinases phosphorylation and HR repair pathways. In addition, the VPA altered the tumor microenvironment and reduced tumor burden by recruiting macrophages to tumor sites; the Kaplan-Meier analysis showed that patients with high pRPA2 expression had significantly worse survival. Overall, our findings demonstrated that VPA influences HR repair and cell cycle through down-regulating MUS81-pRPA2 pathway in response to HU treatment.
Collapse
Affiliation(s)
- Benyu Su
- Department of Occupational and Environmental Health, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - David Lim
- School of Health Sciences, Western Sydney University, Campbelltown, NSW, Australia.,College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia
| | - Zhujun Tian
- Department of Occupational and Environmental Health, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, China.,School of Public Health and Management, Wenzhou Medical University, Wenzhou, China
| | - Guochao Liu
- Department of Occupational and Environmental Health, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Chenxia Ding
- Department of Occupational and Environmental Health, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Zuchao Cai
- Department of Occupational and Environmental Health, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Chen Chen
- Department of Occupational and Environmental Health, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Fengmei Zhang
- Department of Occupational and Environmental Health, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Zhihui Feng
- Department of Occupational and Environmental Health, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, China
| |
Collapse
|
11
|
Rivero-Rodríguez F, Díaz-Quintana A, Velázquez-Cruz A, González-Arzola K, Gavilan MP, Velázquez-Campoy A, Ríos RM, De la Rosa MA, Díaz-Moreno I. Inhibition of the PP2A activity by the histone chaperone ANP32B is long-range allosterically regulated by respiratory cytochrome c. Redox Biol 2021; 43:101967. [PMID: 33882408 PMCID: PMC8082267 DOI: 10.1016/j.redox.2021.101967] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 04/03/2021] [Accepted: 04/03/2021] [Indexed: 12/26/2022] Open
Abstract
Repair of injured DNA relies on nucleosome dismantling by histone chaperones and de-phosphorylation events carried out by Protein Phosphatase 2A (PP2A). Typical histone chaperones are the Acidic leucine-rich Nuclear Phosphoprotein 32 family (ANP32) members, e.g. ANP32A, which is also a well-known PP2A inhibitor (a.k.a. I1PP2A). Here we report the novel interaction between the endogenous family member B—so-called ANP32B—and endogenous cytochrome c in cells undergoing camptothecin-induced DNA damage. Soon after DNA lesions but prior to caspase cascade activation, the hemeprotein translocates to the nucleus to target the Low Complexity Acidic Region (LCAR) of ANP32B; in a similar way, our group recently reported that the hemeprotein targets the acidic domain of SET/Template Activating Factor-Iβ (SET/TAF-Iβ), which is another histone chaperone and PP2A inhibitor (a.k.a. I2PP2A). The nucleosome assembly activity of ANP32B is indeed unaffected by cytochrome c binding. Like ANP32A, ANP32B inhibits PP2A activity and is thus herein referred to as I3PP2A. Our data demonstrates that ANP32B-dependent inhibition of PP2A is regulated by respiratory cytochrome c, which induces long-distance allosteric changes in the structured N-terminal domain of ANP32B upon binding to the C-terminal LCAR. In agreement with the reported role of PP2A in the DNA damage response, we propose a model wherein cytochrome c is translocated from the mitochondria into the nucleus upon DNA damage to modulate PP2A activity via its interaction with ANP32B. Respiratory cytochrome c interacts with ANP32B under DNA damage in the nucleus. Cytochrome c binding to ANP32B LCAR restores ANP32B-mediated PP2A inhibition. Cytochrome c emerges as a DNA Damage Response regulator.
Collapse
Affiliation(s)
- Francisco Rivero-Rodríguez
- Institute for Chemical Research (IIQ), Scientific Research Centre "Isla de La Cartuja" (cicCartuja), University of Seville, CSIC, Avda. Américo Vespucio 49, Seville, 41092, Spain
| | - Antonio Díaz-Quintana
- Institute for Chemical Research (IIQ), Scientific Research Centre "Isla de La Cartuja" (cicCartuja), University of Seville, CSIC, Avda. Américo Vespucio 49, Seville, 41092, Spain
| | - Alejandro Velázquez-Cruz
- Institute for Chemical Research (IIQ), Scientific Research Centre "Isla de La Cartuja" (cicCartuja), University of Seville, CSIC, Avda. Américo Vespucio 49, Seville, 41092, Spain
| | - Katiuska González-Arzola
- Institute for Chemical Research (IIQ), Scientific Research Centre "Isla de La Cartuja" (cicCartuja), University of Seville, CSIC, Avda. Américo Vespucio 49, Seville, 41092, Spain
| | - Maria P Gavilan
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, University of Seville, CSIC, University Pablo de Olavide, Avda. Américo Vespucio 24, Seville, 41092, Spain
| | - Adrián Velázquez-Campoy
- Institute for Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSICBIFI,and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018, Zaragoza, Spain; Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009, Zaragoza, Spain; Instituto de Investigación Sanitaria de Aragón (IIS Aragon), Zaragoza, Spain; Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), 28029, Madrid, Spain; Fundación ARAID, Gobierno de Aragón, 50018, Zaragoza, Spain
| | - Rosa M Ríos
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, University of Seville, CSIC, University Pablo de Olavide, Avda. Américo Vespucio 24, Seville, 41092, Spain
| | - Miguel A De la Rosa
- Institute for Chemical Research (IIQ), Scientific Research Centre "Isla de La Cartuja" (cicCartuja), University of Seville, CSIC, Avda. Américo Vespucio 49, Seville, 41092, Spain
| | - Irene Díaz-Moreno
- Institute for Chemical Research (IIQ), Scientific Research Centre "Isla de La Cartuja" (cicCartuja), University of Seville, CSIC, Avda. Américo Vespucio 49, Seville, 41092, Spain.
| |
Collapse
|
12
|
Swift ML, Beishline K, Flashner S, Azizkhan-Clifford J. DSB repair pathway choice is regulated by recruitment of 53BP1 through cell cycle-dependent regulation of Sp1. Cell Rep 2021; 34:108840. [PMID: 33730584 DOI: 10.1016/j.celrep.2021.108840] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 09/13/2020] [Accepted: 02/17/2021] [Indexed: 12/14/2022] Open
Abstract
Although many of the factors, epigenetic changes, and cell cycle stages that distinguish repair of double-strand breaks (DSBs) by homologous recombination (HR) from non-homologous end joining (NHEJ) are known, the underlying mechanisms that determine pathway choice are incompletely understood. Previously, we found that the transcription factor Sp1 is recruited to DSBs and is necessary for repair. Here, we demonstrate that Sp1 localizes to DSBs in G1 and is necessary for recruitment of the NHEJ repair factor, 53BP1. Phosphorylation of Sp1-S59 in early S phase evicts Sp1 and 53BP1 from the break site; inhibition of that phosphorylation results in 53BP1 and Sp1 remaining at DSBs in S phase cells, precluding BRCA1 binding and suppressing HR. Expression of Sp1-S59A increases sensitivity of BRCA1+/+ cells to poly (ADP-ribose) polymerase (PARP) inhibition similar to BRCA1 deficiency. These data demonstrate how Sp1 integrates the cell cycle and DSB repair pathway choice to favor NHEJ.
Collapse
Affiliation(s)
- Michelle L Swift
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Kate Beishline
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Samuel Flashner
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Jane Azizkhan-Clifford
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA, USA.
| |
Collapse
|
13
|
Caldwell CC, Spies M. Dynamic elements of replication protein A at the crossroads of DNA replication, recombination, and repair. Crit Rev Biochem Mol Biol 2020; 55:482-507. [PMID: 32856505 PMCID: PMC7821911 DOI: 10.1080/10409238.2020.1813070] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 08/18/2020] [Accepted: 08/18/2020] [Indexed: 01/19/2023]
Abstract
The heterotrimeric eukaryotic Replication protein A (RPA) is a master regulator of numerous DNA metabolic processes. For a long time, it has been viewed as an inert protector of ssDNA and a platform for assembly of various genome maintenance and signaling machines. Later, the modular organization of the RPA DNA binding domains suggested a possibility for dynamic interaction with ssDNA. This modular organization has inspired several models for the RPA-ssDNA interaction that aimed to explain how RPA, the high-affinity ssDNA binding protein, is replaced by the downstream players in DNA replication, recombination, and repair that bind ssDNA with much lower affinity. Recent studies, and in particular single-molecule observations of RPA-ssDNA interactions, led to the development of a new model for the ssDNA handoff from RPA to a specific downstream factor where not only stability and structural rearrangements but also RPA conformational dynamics guide the ssDNA handoff. Here we will review the current knowledge of the RPA structure, its dynamic interaction with ssDNA, and how RPA conformational dynamics may be influenced by posttranslational modification and proteins that interact with RPA, as well as how RPA dynamics may be harnessed in cellular decision making.
Collapse
Affiliation(s)
- Colleen C. Caldwell
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242
| | - Maria Spies
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242
| |
Collapse
|
14
|
Dueva R, Iliakis G. Replication protein A: a multifunctional protein with roles in DNA replication, repair and beyond. NAR Cancer 2020; 2:zcaa022. [PMID: 34316690 PMCID: PMC8210275 DOI: 10.1093/narcan/zcaa022] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/23/2020] [Accepted: 08/27/2020] [Indexed: 02/07/2023] Open
Abstract
Single-stranded DNA (ssDNA) forms continuously during DNA replication and is an important intermediate during recombination-mediated repair of damaged DNA. Replication protein A (RPA) is the major eukaryotic ssDNA-binding protein. As such, RPA protects the transiently formed ssDNA from nucleolytic degradation and serves as a physical platform for the recruitment of DNA damage response factors. Prominent and well-studied RPA-interacting partners are the tumor suppressor protein p53, the RAD51 recombinase and the ATR-interacting proteins ATRIP and ETAA1. RPA interactions are also documented with the helicases BLM, WRN and SMARCAL1/HARP, as well as the nucleotide excision repair proteins XPA, XPG and XPF–ERCC1. Besides its well-studied roles in DNA replication (restart) and repair, accumulating evidence shows that RPA is engaged in DNA activities in a broader biological context, including nucleosome assembly on nascent chromatin, regulation of gene expression, telomere maintenance and numerous other aspects of nucleic acid metabolism. In addition, novel RPA inhibitors show promising effects in cancer treatment, as single agents or in combination with chemotherapeutics. Since the biochemical properties of RPA and its roles in DNA repair have been extensively reviewed, here we focus on recent discoveries describing several non-canonical functions.
Collapse
Affiliation(s)
- Rositsa Dueva
- Institute of Medical Radiation Biology, University of Duisburg-Essen Medical School, 45122 Essen, Germany
| | - George Iliakis
- Institute of Medical Radiation Biology, University of Duisburg-Essen Medical School, 45122 Essen, Germany
| |
Collapse
|
15
|
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.
Collapse
|
16
|
Lai Y, Zhu M, Wu W, Rokutanda N, Togashi Y, Liang W, Ohta T. HERC2 regulates RPA2 by mediating ATR-induced Ser33 phosphorylation and ubiquitin-dependent degradation. Sci Rep 2019; 9:14257. [PMID: 31582797 PMCID: PMC6776656 DOI: 10.1038/s41598-019-50812-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 09/19/2019] [Indexed: 01/26/2023] Open
Abstract
Replication protein A (RPA) binds to and stabilizes single-stranded DNA and is essential for the genome stability. We reported that an E3 ubiquitin ligase, HERC2, suppresses G-quadruplex (G4) DNA by regulating RPA-helicase complexes. However, the precise mechanism of HERC2 on RPA is as yet largely unknown. Here, we show essential roles for HERC2 on RPA2 status: induction of phosphorylation and degradation of the modified form. HERC2 interacted with RPA through the C-terminal HECT domain. Ubiquitination of RPA2 was inhibited by HERC2 depletion and rescued by reintroduction of the C-terminal fragment of HERC2. ATR-mediated phosphorylation of RPA2 at Ser33 induced by low-level replication stress was inhibited by depletion of HERC2. Contrary, cells lacking HERC2 catalytic residues constitutively expressed an increased level of Ser33-phosphorylated RPA2. HERC2-mediated ubiquitination of RPA2 was abolished by an ATR inhibitor, supporting a hypothesis that the ubiquitinated RPA2 is a phosphorylated subset. Functionally, HERC2 E3 activity has an epistatic relationship with RPA in the suppression of G4 when judged with siRNA knockdown experiments. Together, these results suggest that HERC2 fine-tunes ATR-phosphorylated RPA2 levels through induction and degradation, a mechanism that could be critical for the suppression of secondary DNA structures during cell proliferation.
Collapse
Affiliation(s)
- Yongqiang Lai
- Department of Translational Oncology, St. Marianna University Graduate School of Medicine, Kawasaki, Japan.,Department of General Surgery, The People's Hospital of Gaoming District of Foshan City, Foshan city, Guangdong province, China
| | - Mingzhang Zhu
- Department of Translational Oncology, St. Marianna University Graduate School of Medicine, Kawasaki, Japan.,Department of General Surgery, The People's Hospital of Gaoming District of Foshan City, Foshan city, Guangdong province, China
| | - Wenwen Wu
- Department of Translational Oncology, St. Marianna University Graduate School of Medicine, Kawasaki, Japan
| | - Nana Rokutanda
- Department of Translational Oncology, St. Marianna University Graduate School of Medicine, Kawasaki, Japan.,Oncology TA Division/Research & Development, AstraZeneca Japan, Osaka, Japan
| | - Yukiko Togashi
- Department of Translational Oncology, St. Marianna University Graduate School of Medicine, Kawasaki, Japan
| | - Weixin Liang
- Department of General Surgery, The People's Hospital of Gaoming District of Foshan City, Foshan city, Guangdong province, China
| | - Tomohiko Ohta
- Department of Translational Oncology, St. Marianna University Graduate School of Medicine, Kawasaki, Japan.
| |
Collapse
|
17
|
Perl AL, O'Connor CM, Fa P, Mayca Pozo F, Zhang J, Zhang Y, Narla G. Protein phosphatase 2A controls ongoing DNA replication by binding to and regulating cell division cycle 45 (CDC45). J Biol Chem 2019; 294:17043-17059. [PMID: 31562245 DOI: 10.1074/jbc.ra119.010432] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 09/20/2019] [Indexed: 11/06/2022] Open
Abstract
Genomic replication is a highly regulated process and represents both a potential benefit and liability to rapidly dividing cells; however, the precise post-translational mechanisms regulating genomic replication are incompletely understood. Protein phosphatase 2A (PP2A) is a serine/threonine phosphatase that regulates a diverse array of cellular processes. Here, utilizing both a gain-of-function chemical biology approach and loss-of-function genetic approaches to modulate PP2A activity, we found that PP2A regulates DNA replication. We demonstrate that increased PP2A activity can interrupt ongoing DNA replication, resulting in a prolonged S phase. The impaired replication resulted in a collapse of replication forks, inducing dsDNA breaks, homologous recombination, and a PP2A-dependent replication stress response. Additionally, we show that during replication, PP2A exists in complex with cell division cycle 45 (CDC45) and that increased PP2A activity caused dissociation of CDC45 and polymerase α from the replisome. Furthermore, we found that individuals harboring mutations in the PP2A Aα gene have a higher fraction of genomic alterations, suggesting that PP2A regulates ongoing replication as a mechanism for maintaining genomic integrity. These results reveal a new function for PP2A in regulating ongoing DNA replication and a potential role for PP2A in the intra-S-phase checkpoint.
Collapse
Affiliation(s)
- Abbey L Perl
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
| | - Caitlin M O'Connor
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
| | - Pengyan Fa
- Department of Radiation Oncology, Ohio State University James Comprehensive Cancer Center and College of Medicine, Columbus, Ohio 43210
| | - Franklin Mayca Pozo
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
| | - Junran Zhang
- Department of Radiation Oncology, Ohio State University James Comprehensive Cancer Center and College of Medicine, Columbus, Ohio 43210
| | - Youwei Zhang
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
| | - Goutham Narla
- Department of Internal Medicine, Case Comprehensive Cancer Center, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106 .,Department of Internal Medicine, Division of Genetic Medicine, University of Michigan, Ann Arbor, Michigan 48105
| |
Collapse
|
18
|
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.
Collapse
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
| |
Collapse
|
19
|
Herreros-Villanueva M, Chen CC, Tsai EM, Er TK. Endometriosis-associated ovarian cancer: What have we learned so far? Clin Chim Acta 2019; 493:63-72. [PMID: 30776361 DOI: 10.1016/j.cca.2019.02.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 02/13/2019] [Accepted: 02/14/2019] [Indexed: 02/07/2023]
Abstract
Endometriosis is defined as the presence of ectopic endometrial tissue outside of the uterine cavity, most commonly in the ovaries and peritoneum. It is a complex disease that is influenced by multiple factors. It is also a common gynecological disorder and affects approximately 10-15% of all women of reproductive age. Recent molecular and pathological studies indicate that endometriosis may serve as a precursor of ovarian cancer (endometriosis-associated ovarian cancer, EAOC), particularly endometrioid and clear cell ovarian cancers. Although histological and epidemiological studies have demonstrated that endometriosis has a malignant potential, the molecular mechanism that underlies the malignant transformation of endometriosis is still controversial, and the precise mechanism of carcinogenesis must be fully elucidated. Currently, the development and improvement of a new sequencing technology, next-generation sequencing (NGS), has been increasingly relevant in cancer genomics research. Recently, NGS has also been utilized in clinical oncology to advance the personalized treatment of cancer. In addition, the sensitivity, speed, and cost make NGS a highly attractive platform compared to other sequencing modalities. For this reason, NGS may lead to the identification of driver mutations and underlying pathways associated with EAOC. Here, we present an overview of the molecular pathways that have led to the current opinions on the relationship between endometriosis and ovarian cancer.
Collapse
Affiliation(s)
- M Herreros-Villanueva
- Department of Gastroenterology, Hospital Donostia/Instituto Biodonostia, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Universidad del País Vasco UPV/EHU, San Sebastián, Spain
| | - Chih-Chieh Chen
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung, Taiwan; Rapid Screening Research Center for Toxicology and Biomedicine, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Eing-Mei Tsai
- Department of Obstetrics and Gynecology, Kaohsiung Medical University Hospital, Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Tze-Kiong Er
- Division of Laboratory Medicine, Asia University Hospital, Asia University, Taichung, Taiwan; Deparment of Food Nutrition and Health Biotechnology, Asia University, Taichung, Taiwan; Deparment of Biotechnology, Asia University, Taichung, Taiwan; Deparment of Nursing, Asia University, Taichung, Taiwan.
| |
Collapse
|
20
|
Jarman PJ, Noakes F, Fairbanks S, Smitten K, Griffiths IK, Saeed HK, Thomas JA, Smythe C. Exploring the Cytotoxicity, Uptake, Cellular Response, and Proteomics of Mono- and Dinuclear DNA Light-Switch Complexes. J Am Chem Soc 2018; 141:2925-2937. [DOI: 10.1021/jacs.8b09999] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Paul J. Jarman
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, U.K
| | - Felicity Noakes
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, U.K
- Department of Chemistry, University of Sheffield, Sheffield S10 2TN, U.K
| | - Simon Fairbanks
- Department of Chemistry, University of Sheffield, Sheffield S10 2TN, U.K
| | - Kirsty Smitten
- Department of Chemistry, University of Sheffield, Sheffield S10 2TN, U.K
| | | | - Hiwa K. Saeed
- Department of Chemistry, University of Sheffield, Sheffield S10 2TN, U.K
| | - Jim A. Thomas
- Department of Chemistry, University of Sheffield, Sheffield S10 2TN, U.K
| | - Carl Smythe
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, U.K
| |
Collapse
|
21
|
Byrne BM, Oakley GG. Replication protein A, the laxative that keeps DNA regular: The importance of RPA phosphorylation in maintaining genome stability. Semin Cell Dev Biol 2018; 86:112-120. [PMID: 29665433 DOI: 10.1016/j.semcdb.2018.04.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/30/2018] [Accepted: 04/06/2018] [Indexed: 11/25/2022]
Abstract
The eukaryotic ssDNA-binding protein, Replication protein A (RPA), was first discovered almost three decades ago. Since then, much progress has been made to elucidate the critical roles for RPA in DNA metabolic pathways that help promote genomic stability. The canonical RPA heterotrimer (RPA1-3) is an essential coordinator of DNA metabolism that interacts with ssDNA and numerous protein partners to coordinate its roles in DNA replication, repair, recombination and telomere maintenance. An alternative form of RPA, termed aRPA, is formed by a complex of RPA4 with RPA1 and RPA3. aRPA is expressed differentially in cells compared to canonical RPA and has been shown to inhibit canonical RPA function while allowing for regular maintenance of cell viability. Interestingly, while aRPA is defective in DNA replication and cell cycle progression, it was shown to play a supporting role in nucleotide excision repair and recombination. The binding domains of canonical RPA interact with a growing number of partners involved in numerous genome maintenance processes. The protein interactions of the RPA-ssDNA complex are not only governed by competition between the binding proteins but also by post-translation modifications such as phosphorylation. Phosphorylation of RPA2 is an important post-translational modification of the RPA complex, and is essential for directing context-specific functions of the RPA complex in the DNA damage response. Due to the importance of RPA in cellular metabolism, it was identified as an appealing target for chemotherapeutic drug development that could be used in future cancer treatment regimens.
Collapse
Affiliation(s)
- Brendan M Byrne
- University of Nebraska Medical Center Department of Oral Biology, Lincoln NE, USA.
| | - Gregory G Oakley
- University of Nebraska Medical Center Department of Oral Biology, Lincoln NE, USA; Eppley Cancer Center, Omaha NE, USA.
| |
Collapse
|
22
|
Distinguishing the progression of an endometrioma: Benign or malignant? Eur J Obstet Gynecol Reprod Biol 2018; 230:79-84. [DOI: 10.1016/j.ejogrb.2018.09.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 08/26/2018] [Accepted: 09/12/2018] [Indexed: 12/12/2022]
|
23
|
Bhattacharya D, Hiregange D, Rao BJ. ATR kinase regulates its attenuation via PPM1D phosphatase recruitment to chromatin during recovery from DNA replication stress signalling. J Biosci 2018; 43:25-47. [PMID: 29485113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In eukaryotes, in response to replication stress, DNA damage response kinase, ATR is activated, whose signalling abrogation leads to cell lethality due to aberrant fork remodelling and excessive origin firing. Here we report that inhibition of ATR kinase activity specifically during replication stress recovery results in persistent ATR signalling, evidenced by the presence of ATR-dependent phosphorylation marks (gamma H2AX, pChk1 and pRad17) and delayed cell cycle re-entry. Further, such disruption of ATR signalling attenuation leads to double-strand breaks, fork collapse and thereby 'replication catastrophe'. PPM1D phosphatase, a nucleolar localized protein, relocates to chromatin during replication stress and reverts back to nucleolus following stress recovery, under the control of ATR kinase action. Inhibition of ATR kinase activity, specifically during post replication stress, triggers dislodging of the chromatin-bound PPM1D from nucleus to cytoplasm followed by its degradation, thereby leading to persistence of activated ATR marks in the nuclei. Chemical inhibition of PPM1D activity or SiRNA mediated depletion of the protein during post replication stress recovery 'phenocopies' ATR kinase inhibition by failing to attenuate ATR signalling. Collectively, our observations suggest a novel role of ATR kinase in mediating its own signal attenuation via PPM1D recruitment to chromatin as an essential mechanism for restarting the stalled forks, cell-cycle re-entry and cellular recovery from replication stress.
Collapse
Affiliation(s)
- Debadrita Bhattacharya
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai 400 005, India
| | | | | |
Collapse
|
24
|
Protein interactomes of protein phosphatase 2A B55 regulatory subunits reveal B55-mediated regulation of replication protein A under replication stress. Sci Rep 2018; 8:2683. [PMID: 29422626 PMCID: PMC5805732 DOI: 10.1038/s41598-018-21040-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 01/24/2018] [Indexed: 11/24/2022] Open
Abstract
The specific function of PP2A, a major serine/threonine phosphatase, is mediated by regulatory targeting subunits, such as members of the B55 family. Although implicated in cell division and other pathways, the specific substrates and functions of B55 targeting subunits are largely undefined. In this study we identified over 100 binding proteins of B55α and B55β in Xenopus egg extracts that are involved in metabolism, mitochondria function, molecular trafficking, cell division, cytoskeleton, DNA replication, DNA repair, and cell signaling. Among the B55α and B55β-associated proteins were numerous mitotic regulators, including many substrates of CDK1. Consistently, upregulation of B55α accelerated M-phase exit and inhibited M-phase entry. Moreover, specific substrates of CDK2, including factors of DNA replication and chromatin remodeling were identified within the interactomes of B55α and B55β, suggesting a role for these phosphatase subunits in DNA replication. In particular, we confirmed in human cells that B55α binds RPA and mediates the dephosphorylation of RPA2. The B55-RPA association is disrupted after replication stress, consistent with the induction of RPA2 phosphorylation. Thus, we report here a new mechanism that accounts for both how RPA phosphorylation is modulated by PP2A and how the phosphorylation of RPA2 is abruptly induced after replication stress.
Collapse
|
25
|
Bhattacharya D, Hiregange D, Rao BJ. ATR kinase regulates its attenuation via PPM1D phosphatase recruitment to chromatin during recovery from DNA replication stress signalling. J Biosci 2018. [DOI: 10.1007/s12038-018-9736-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
|
26
|
Taleski G, Sontag E. Protein phosphatase 2A and tau: an orchestrated 'Pas de Deux'. FEBS Lett 2017; 592:1079-1095. [PMID: 29121398 DOI: 10.1002/1873-3468.12907] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 10/18/2017] [Accepted: 11/02/2017] [Indexed: 12/21/2022]
Abstract
The neuronal microtubule-associated protein tau serves a critical role in regulating axonal microtubule dynamics to support neuronal and synaptic functions. Furthermore, it contributes to glutamatergic regulation and synaptic plasticity. Emerging evidence also suggests that tau serves as a signaling scaffold. Tau function and subcellular localization are tightly regulated, in part, by the orchestrated interplay between phosphorylation and dephosphorylation events. Significantly, protein phosphatase type 2A (PP2A), encompassing the regulatory PPP2R2A (or Bα) subunit, is a major brain heterotrimeric enzyme and the primary tau Ser/Thr phosphatase in vivo. Herein, we closely examine how the intimate and compartmentalized interactions between PP2A and tau regulate tau phosphorylation and function, and play an essential role in neuronal homeostasis. We also review evidence supporting a strong link between deregulation of tau-PP2A functional interactions and the molecular underpinnings of various neurodegenerative diseases collectively called tauopathies. Lastly, we discuss the opportunities and associated challenges in more specifically targeting PP2A-tau interactions for drug development for tauopathies.
Collapse
Affiliation(s)
- Goce Taleski
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, Hunter Medical Research Institute, University of Newcastle, Callaghan, Australia
| | - Estelle Sontag
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, Hunter Medical Research Institute, University of Newcastle, Callaghan, Australia
| |
Collapse
|
27
|
Tian Y, Liu G, Wang H, Tian Z, Cai Z, Zhang F, Luo Y, Wang S, Guo G, Wang X, Powell S, Feng Z. Valproic acid sensitizes breast cancer cells to hydroxyurea through inhibiting RPA2 hyperphosphorylation-mediated DNA repair pathway. DNA Repair (Amst) 2017; 58:1-12. [PMID: 28837865 DOI: 10.1016/j.dnarep.2017.08.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 06/28/2017] [Accepted: 08/07/2017] [Indexed: 11/24/2022]
Abstract
It was reported that valproic acid (VPA, a histone deacetylase inhibitor) can sensitize cancer cells to hydroxyurea (HU, a ribonucleotide reductase inhibitor) for chemotherapy, although the mechanism of VPA-induced HU sensitization is unclear. In this study, we systematically characterized VPA-induced HU sensitization of breast cancer cells. Multiple breast cancer cell models were employed to investigate whether the safe concentration of 0.5mM VPA and 2mM HU can result in DNA double-strand breaks (DSBs) and impact cell survival. Furthermore, the underlying mechanism was explored through cell biology assays, including clonogenic survival, homologous recombination (HR) activity, immunoblot and immunofluorescence. We found that VPA and HU cooperatively suppressed cancer cell survival. VPA resulted in the accumulation of more DNA double-strand breaks (DSBs) in response to HU-induced replication arrest and was able to block HU-stimulated homologous recombination (HR) through inhibiting the activity of two key HR repair proteins by hyperphosphorylation of replication protein A2 (RPA2-p) and recombinase Rad51. However, apoptosis was not detected under this condition. In addition, the results from the survival fraction in the cells expressing defective RPA2-p showed that VPA disrupted the HU-induced RPA2-p-Rad51-mediated HR pathway. Importantly, these findings were further supported by analyzing primary-culture cells from the tissue of chemical carcinogen (DMBA)-induced breast cancer in rats. Thus, our data demonstrated that VPA and HU synergistically suppressed tumor cells via disturbing RPA2-p-mediated DNA repair pathway, which provides a new way for combining chemotherapeutic drugs to sensitize breast cancer cells.
Collapse
Affiliation(s)
- Youjia Tian
- Department of Occupational Health and Occupational Medicine, The Public Health School, Shandong University, Shandong, Jinan, 250012, China
| | - Guochao Liu
- Department of Occupational Health and Occupational Medicine, The Public Health School, Shandong University, Shandong, Jinan, 250012, China
| | - Hui Wang
- Department of Occupational Health and Occupational Medicine, The Public Health School, Shandong University, Shandong, Jinan, 250012, China
| | - Zhujun Tian
- Department of Occupational Health and Occupational Medicine, The Public Health School, Shandong University, Shandong, Jinan, 250012, China
| | - Zuchao Cai
- Department of Occupational Health and Occupational Medicine, The Public Health School, Shandong University, Shandong, Jinan, 250012, China
| | - Fengmei Zhang
- Department of Occupational Health and Occupational Medicine, The Public Health School, Shandong University, Shandong, Jinan, 250012, China
| | - Yue Luo
- Department of Occupational Health and Occupational Medicine, The Public Health School, Shandong University, Shandong, Jinan, 250012, China
| | - Shue Wang
- Department of Occupational Health and Occupational Medicine, The Public Health School, Shandong University, Shandong, Jinan, 250012, China
| | - Gongshe Guo
- The Second Hospital of Shandong University, Shandong, Jinan, China
| | - Xiaowei Wang
- Department of Radiation Oncology, Washington University, School of Medicine, St. Louis, USA
| | - Simon Powell
- Department of Radiation Oncology and Molecular Biology Program, Memorial Sloan Kettering Cancer Center, NY, USA
| | - Zhihui Feng
- Department of Occupational Health and Occupational Medicine, The Public Health School, Shandong University, Shandong, Jinan, 250012, China.
| |
Collapse
|
28
|
Zhou H, Luo W, Zeng C, Zhang Y, Wang L, Yao W, Nie C. PP2A mediates apoptosis or autophagic cell death in multiple myeloma cell lines. Oncotarget 2017; 8:80770-80789. [PMID: 29113343 PMCID: PMC5655238 DOI: 10.18632/oncotarget.20415] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 06/27/2017] [Indexed: 02/05/2023] Open
Abstract
The crosstalk between apoptosis and autophagy contributes to tumorigenesis and cancer therapy. The process by which BetA (betulinic acid), a naturally occurring triterpenoid, regulates apoptosis and autophagy as a cancer therapy is unclear. In this study, we show for the first time that protein phosphatase 2A (PP2A) acts as a switch to regulate apoptosis and autophagic cell death mediated by BetA. Under normal conditions, caspase-3 is activated by the mitochondrial pathway upon BetA treatment. Activated caspase-3 cleaves the A subunit of PP2A (PP2A/A), resulting in the association of PP2A and Akt. This association inactivates Akt to initiate apoptosis. Overexpression of Bcl-2 attenuates the mitochondrial apoptosis pathway, resulting in caspase-3 inactivation and the dissociation of PP2A and Akt. PP2A isolated from Akt binds with DAPK to induce autophagic cell death. Meanwhile, in vivo tumor experiments have demonstrated that BetA initiates different types of cell death in a myeloma xenograft model. Thus, PP2A can shift myeloma cells from apoptosis to autophagic cell death. These findings have important implications for the therapeutic application of BetA, particularly against apoptosis-resistant cancers.
Collapse
Affiliation(s)
- Hang Zhou
- Department of Chemotherapy, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Wei Luo
- Department of Pharmacy, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Chao Zeng
- Department of Gastroenterology, the Third People's Hospital of Chengdu, Chengdu, China
| | - Yu Zhang
- Department of Oncology, Guizhou People's Hospital, Guizhou, China
| | - Liyang Wang
- Department of Chemotherapy, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Wenxiu Yao
- Department of Chemotherapy, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Chunlai Nie
- Department of Chemotherapy, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China.,Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| |
Collapse
|
29
|
Luo CW, Wang JY, Hung WC, Peng G, Tsai YL, Chang TM, Chai CY, Lin CH, Pan MR. G9a governs colon cancer stem cell phenotype and chemoradioresistance through PP2A-RPA axis-mediated DNA damage response. Radiother Oncol 2017; 124:395-402. [PMID: 28351524 DOI: 10.1016/j.radonc.2017.03.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Revised: 02/28/2017] [Accepted: 03/01/2017] [Indexed: 12/18/2022]
Abstract
BACKGROUND AND PURPOSE Neoadjuvant concurrent chemoradiotherapy (CCRT) is a standard treatment of locally advanced colon cancer cell (CRC). In order to maximize efficacy and minimize toxicity, new drugs have been developed and used in combination with CCRT. Recently, it has been shown that G9a plays a role in mediating phenotypes of cancer stem cells (CSCs). This study aimed to characterize G9a as a biomarker in predicting therapy response to prevent overtreatment and adverse effects in CRC patients. EXPERIMENTAL DESIGN The primary tumors from 39 patients who received CCRT for rectal cancer were selected. In vivo tumor xenograft models for tumorigenic properties in immunodeficient mice were developed. In vitro stemness ability was performed by tumor-sphere assays, cell response to anti-cancer agents and stemness-related genes analysis. RESULTS Cells survived from radiation treatment, and displayed high levels of G9a. A significantly positive correlation was shown between G9a and CSCs marker CD133 in locally advanced rectal cancer patients with CCRT. Knockdown of G9a increased the sensitivity of cells to radiation treatment and sensitized cells to DNA damage agents through PP2A-RPA axis. CONCLUSIONS Our study theorized that G9a might serve as a novel target in colon cancer, which offers exciting potential in prediction of response to preoperative chemoradiotherapy in patients with advanced CRC.
Collapse
Affiliation(s)
- Chi-Wen Luo
- Department of Pathology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Taiwan
| | - Jaw-Yuan Wang
- Division of Colorectal Surgery, Department of Surgery, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Taiwan; Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Taiwan; Department of Surgery, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Taiwan; Center for Biomarkers and Biotech Drugs, Kaohsiung Medical University, Taiwan; Research Center for Environmental Medicine, Kaohsiung Medical University, Taiwan
| | - Wen-Chun Hung
- National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan
| | - Guang Peng
- Department of Clinical Cancer Prevention, Unit 1013, The University of Texas MD Anderson Cancer Center, Houston, USA
| | - Ya-Li Tsai
- National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan
| | - Tsung-Ming Chang
- National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan
| | - Chee-Yin Chai
- Department of Pathology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Taiwan
| | - Chih-Hung Lin
- Department of Pathology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Taiwan
| | - Mei-Ren Pan
- Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Taiwan; Research Center for Environmental Medicine, Kaohsiung Medical University, Taiwan; Cancer Center, Kaohsiung Medical University Hospital, Taiwan.
| |
Collapse
|
30
|
Martin LJ, Wong M. Enforced DNA repair enzymes rescue neurons from apoptosis induced by target deprivation and axotomy in mouse models of neurodegeneration. Mech Ageing Dev 2016; 161:149-162. [PMID: 27364693 DOI: 10.1016/j.mad.2016.06.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 06/23/2016] [Accepted: 06/26/2016] [Indexed: 02/06/2023]
Abstract
It is unknown whether DNA damage accumulation is an upstream instigator or secondary effect of the cell death process in different populations of adult postmitotic neurons in the central nervous system. In two different mouse models of injury-induced neurodegeneration characterized by relatively synchronous accumulation of mitochondria, oxidative stress, and DNA damage prior to neuronal apoptosis, we enforced the expression of human 8-oxoguanine DNA glycosylase (hOGG1) and human apurinic-apyrimidinic endonuclease-1/Ref1 (hAPE) using recombinant adenoviruses (Ad). Thalamic lateral geniculate neurons and lumbar spinal cord motor neurons were transduced by Ad-hOGG1 and Ad-hAPE injections into the occipital cortex and skeletal muscle, respectively, prior to their target deprivation- and axotomy-induced retrograde apoptosis. Enforced expression of hOGG1 and hAPE in thalamus and spinal cord was confirmed by western blotting and immunohistochemistry. In injured populations of neurons in thalamus and spinal cord, a DNA damage response (DDR) was registered, as shown by localization of phospho-activated p53, Rad17, and replication protein A-32 immunoreactivities, and this DDR was attenuated more effectively by enforced hAPE expression than by hOGG1 expression. Enforced expression of hOGG1 and hAPE significantly protected thalamic neurons and motor neurons from retrograde apoptosis induced by target deprivation and axotomy. We conclude that a DDR response is engaged pre-apoptotically in different types of injured mature CNS neurons and that DNA repair enzymes can regulate the survival of retrogradely dying neurons, suggesting that DNA damage and activation of DDR are upstream mechanisms for this form of adult neurodegeneration in vivo, thus identifying DNA repair as a therapeutic target for neuroprotection.
Collapse
Affiliation(s)
- Lee J Martin
- Department of Pathology, Division of Neuropathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Pathobiology Graduate Training Program, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Margaret Wong
- Department of Pathology, Division of Neuropathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| |
Collapse
|
31
|
Jeong AL, Han S, Lee S, Su Park J, Lu Y, Yu S, Li J, Chun KH, Mills GB, Yang Y. Patient derived mutation W257G of PPP2R1A enhances cancer cell migration through SRC-JNK-c-Jun pathway. Sci Rep 2016; 6:27391. [PMID: 27272709 PMCID: PMC4895347 DOI: 10.1038/srep27391] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 05/17/2016] [Indexed: 01/20/2023] Open
Abstract
Mutation of PPP2R1A has been observed at high frequency in endometrial serous carcinomas but at low frequency in ovarian clear cell carcinoma. However, the biological role of mutation of PPP2R1A in ovarian and endometrial cancer progression remains unclear. In this study, we found that PPP2R1A expression is elevated in high-grade primary tumor patients with papillary serous tumors of the ovary. To determine whether increased levels or mutation of PPP2R1A might contribute to cancer progression, the effects of overexpression or mutation of PPP2R1A on cell proliferation, migration, and PP2A phosphatase activity were investigated using ovarian and endometrial cancer cell lines. Among the mutations, PPP2R1A-W257G enhanced cell migration in vitro through activating SRC-JNK-c-Jun pathway. Overexpression of wild type (WT) PPP2R1A increased its binding ability with B56 regulatory subunits, whereas PPP2R1A-mutations lost the ability to bind to most B56 subunits except B56δ. Total PP2A activity and PPP2R1A-associated PP2Ac activity were significantly increased in cells overexpressing PPP2R1A-WT. In addition, overexpression of PPP2R1A-WT increased cell proliferation in vitro and tumor growth in vivo.
Collapse
Affiliation(s)
- Ae Lee Jeong
- Department of Biological Sciences, Sookmyung Women's University, Seoul 140-742, Republic of Korea
| | - Sora Han
- Department of Biological Sciences, Sookmyung Women's University, Seoul 140-742, Republic of Korea
| | - Sunyi Lee
- Department of Biological Sciences, Sookmyung Women's University, Seoul 140-742, Republic of Korea
| | - Jeong Su Park
- Department of Biological Sciences, Sookmyung Women's University, Seoul 140-742, Republic of Korea
| | - Yiling Lu
- Department of Systems Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Shuangxing Yu
- Department of Systems Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Jane Li
- Department of Systems Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Kyung-Hee Chun
- Department of Biochemistry and Molecular Biology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Republic of Korea
| | - Gordon B Mills
- Department of Systems Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Young Yang
- Department of Biological Sciences, Sookmyung Women's University, Seoul 140-742, Republic of Korea
| |
Collapse
|
32
|
Harley ME, Murina O, Leitch A, Higgs MR, Bicknell LS, Yigit G, Blackford AN, Zlatanou A, Mackenzie KJ, Reddy K, Halachev M, McGlasson S, Reijns MAM, Fluteau A, Martin CA, Sabbioneda S, Elcioglu NH, Altmüller J, Thiele H, Greenhalgh L, Chessa L, Maghnie M, Salim M, Bober MB, Nürnberg P, Jackson SP, Hurles ME, Wollnik B, Stewart GS, Jackson AP. TRAIP promotes DNA damage response during genome replication and is mutated in primordial dwarfism. Nat Genet 2016; 48:36-43. [PMID: 26595769 PMCID: PMC4697364 DOI: 10.1038/ng.3451] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 10/26/2015] [Indexed: 12/11/2022]
Abstract
DNA lesions encountered by replicative polymerases threaten genome stability and cell cycle progression. Here we report the identification of mutations in TRAIP, encoding an E3 RING ubiquitin ligase, in patients with microcephalic primordial dwarfism. We establish that TRAIP relocalizes to sites of DNA damage, where it is required for optimal phosphorylation of H2AX and RPA2 during S-phase in response to ultraviolet (UV) irradiation, as well as fork progression through UV-induced DNA lesions. TRAIP is necessary for efficient cell cycle progression and mutations in TRAIP therefore limit cellular proliferation, providing a potential mechanism for microcephaly and dwarfism phenotypes. Human genetics thus identifies TRAIP as a component of the DNA damage response to replication-blocking DNA lesions.
Collapse
Affiliation(s)
- Margaret E Harley
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - Olga Murina
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - Andrea Leitch
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - Martin R Higgs
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Louise S Bicknell
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - Gökhan Yigit
- Institute of Human Genetics, University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | | | - Anastasia Zlatanou
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Karen J Mackenzie
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - Kaalak Reddy
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - Mihail Halachev
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - Sarah McGlasson
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - Martin A M Reijns
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - Adeline Fluteau
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - Carol-Anne Martin
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | | | - Nursel H Elcioglu
- Department of Pediatric Genetics, Marmara University Pendik Hospital, Istanbul, Turkey
| | - Janine Altmüller
- Institute of Human Genetics, University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
- Cologne Center for Genomics (CCG), University of Cologne, 50931 Cologne, Germany
| | - Holger Thiele
- Cologne Center for Genomics (CCG), University of Cologne, 50931 Cologne, Germany
| | - Lynn Greenhalgh
- Cheshire and Merseyside Clinical Genetics Service, Liverpool Women's Hospital, Liverpool, L12 2AP, UK
| | - Luciana Chessa
- Department of Clinical and Molecular Medicine, University Sapienza, A.O.S. Andrea, I-00189 Roma, Italy
| | - Mohamad Maghnie
- Department of Pediatrics, IRCCS, Giannina Gaslini, University of Genova, 16147 Genova, Italy
| | - Mahmoud Salim
- Department of Pediatric Genetics, Marmara University Pendik Hospital, Istanbul, Turkey
| | - Michael B Bober
- Nemours/Alfred I. duPont Hospital for Children, Wilmington, Delaware 19803, USA
| | - Peter Nürnberg
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
- Cologne Center for Genomics (CCG), University of Cologne, 50931 Cologne, Germany
| | - Stephen P Jackson
- The Gurdon Institute, University of Cambridge, Cambridge, CB2 1QN, UK
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QN, UK
- Wellcome Trust Sanger Institute, Cambridge, CB10 1SA, UK
| | | | - Bernd Wollnik
- Institute of Human Genetics, University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
- Institute of Human Genetics, University Medical Centre Göttingen, 37073 Göttingen, Germany
| | - Grant S Stewart
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Andrew P Jackson
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, EH4 2XU, UK
| |
Collapse
|
33
|
Zuazua-Villar P, Ganesh A, Phear G, Gagou ME, Meuth M. Extensive RPA2 hyperphosphorylation promotes apoptosis in response to DNA replication stress in CHK1 inhibited cells. Nucleic Acids Res 2015; 43:9776-87. [PMID: 26271993 PMCID: PMC4787776 DOI: 10.1093/nar/gkv835] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 08/06/2015] [Indexed: 11/14/2022] Open
Abstract
The replication protein A (RPA)-ssDNA complex formed at arrested replication forks recruits key proteins to activate the ATR-CHK1 signalling cascade. When CHK1 is inhibited during DNA replication stress, RPA2 is extensively hyperphosphorylated. Here, we investigated the role of RPA2 hyperphosphorylation in the fate of cells when CHK1 is inhibited. We show that proteins normally involved in DNA repair (RAD51) or control of RPA phosphorylation (the PP4 protein phosphatase complex) are not recruited to the genome after treatment with CHK1 and DNA synthesis inhibitors. This is not due to RPA2 hyperphosphorylation as suppression of this response does not restore loading suggesting that recruitment requires active CHK1. To determine whether RPA2 hyperphosphorylation protects stalled forks from collapse or induction of apoptosis in CHK1 inhibited cells during replication stress, cells expressing RPA2 genes mutated at key phosphorylation sites were characterized. Mutant RPA2 rescued cells from RPA2 depletion and reduced the level of apoptosis induced by treatment with CHK1 and replication inhibitors however the incidence of double strand breaks was not affected. Our data indicate that RPA2 hyperphosphorylation promotes cell death during replication stress when CHK1 function is compromised but does not appear to be essential for replication fork integrity.
Collapse
Affiliation(s)
- Pedro Zuazua-Villar
- Molecular Oncology Unit, Department of Oncology, School of Medicine and Biomedical Sciences, University of Sheffield, Sheffield S10 2RX, UK
| | - Anil Ganesh
- Molecular Oncology Unit, Department of Oncology, School of Medicine and Biomedical Sciences, University of Sheffield, Sheffield S10 2RX, UK
| | - Geraldine Phear
- Molecular Oncology Unit, Department of Oncology, School of Medicine and Biomedical Sciences, University of Sheffield, Sheffield S10 2RX, UK
| | - Mary E Gagou
- Molecular Oncology Unit, Department of Oncology, School of Medicine and Biomedical Sciences, University of Sheffield, Sheffield S10 2RX, UK
| | - Mark Meuth
- Molecular Oncology Unit, Department of Oncology, School of Medicine and Biomedical Sciences, University of Sheffield, Sheffield S10 2RX, UK
| |
Collapse
|
34
|
Huang JL, Lin CS, Chang CC, Lu YN, Hsu YL, Wong TY, Wang YF. Human JC virus small tumour antigen inhibits nucleotide excision repair and sensitises cells to DNA-damaging agents. Mutagenesis 2015; 30:475-85. [PMID: 25744060 DOI: 10.1093/mutage/gev004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The human JC virus (JCV) is potentially carcinogenic to humans as a Group 2B carcinogen, and it is ubiquitous in human populations. To investigate whether the small tumour (ST) antigen of the JCV contributes to genomic instability, we established cell lines stably expressing the JCV ST and examined its role in DNA repair. Results from host cell reactivation (HCR) assay revealed that the established cell lines exhibited lower nucleotide excision repair (NER) activity than the vector control cells did. The presence of γ-H2AX, a marker of DNA damage, indicated that the established cell line contained more DNA damage foci compared with vector control cells. Furthermore, the results of clonogenic analyses indicated that the JCV ST-expressing cells were more sensitive than the vector control cells to ultraviolet (UV) irradiation and cisplatin treatment. Micronuclei formation assay revealed that the JCV ST-positive cells presented more chromosomal breakages than did the JCV ST-negative cells, particularly after exposure to DNA-damaging agents. The xeroderma pigmentosum Group D protein, a DNA helicase involved in NER, was downregulated in the JCV ST-positive cells in response to UV irradiation. The effect of the protein phosphatase 2A (PP2A) inhibitor okadaic acid on NER was similar to that of the ST, which is a PP2A-binding protein. Therefore, the deactivation of the PP2A might underlie ST-mediated NER inhibition. The results of this study indicate that exposing JCV ST-positive cells to DNA-damaging agents causes genomic instability, which contributes to carcinogenesis. Our data provide further evidence on the association between the JCV ST and human cancer.
Collapse
Affiliation(s)
- Jau-Ling Huang
- Department of Bioscience Technology, College of Health Science, Chang Jung Christian University, Tainan, Taiwan, Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan, Division of Nephrology, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan, School of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Chang-Shen Lin
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Chia-Chu Chang
- Division of Nephrology, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan, School of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Yu-Ning Lu
- Department of Bioscience Technology, College of Health Science, Chang Jung Christian University, Tainan, Taiwan, Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan, Division of Nephrology, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan, School of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Yu-Ling Hsu
- Department of Bioscience Technology, College of Health Science, Chang Jung Christian University, Tainan, Taiwan, Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan, Division of Nephrology, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan, School of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Tzyy-Yue Wong
- Department of Bioscience Technology, College of Health Science, Chang Jung Christian University, Tainan, Taiwan, Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan, Division of Nephrology, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan, School of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Yu-Fei Wang
- Department of Bioscience Technology, College of Health Science, Chang Jung Christian University, Tainan, Taiwan, Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan, Division of Nephrology, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan, School of Medicine, Chung Shan Medical University, Taichung, Taiwan
| |
Collapse
|
35
|
The DNA damage response and checkpoint adaptation in Saccharomyces cerevisiae: distinct roles for the replication protein A2 (Rfa2) N-terminus. Genetics 2015; 199:711-27. [PMID: 25595672 PMCID: PMC4349066 DOI: 10.1534/genetics.114.173211] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In response to DNA damage, two general but fundamental processes occur in the cell: (1) a DNA lesion is recognized and repaired, and (2) concomitantly, the cell halts the cell cycle to provide a window of opportunity for repair to occur. An essential factor for a proper DNA-damage response is the heterotrimeric protein complex Replication Protein A (RPA). Of particular interest is hyperphosphorylation of the 32-kDa subunit, called RPA2, on its serine/threonine-rich amino (N) terminus following DNA damage in human cells. The unstructured N-terminus is often referred to as the phosphorylation domain and is conserved among eukaryotic RPA2 subunits, including Rfa2 in Saccharomyces cerevisiae. An aspartic acid/alanine-scanning and genetic interaction approach was utilized to delineate the importance of this domain in budding yeast. It was determined that the Rfa2 N-terminus is important for a proper DNA-damage response in yeast, although its phosphorylation is not required. Subregions of the Rfa2 N-terminus important for the DNA-damage response were also identified. Finally, an Rfa2 N-terminal hyperphosphorylation-mimetic mutant behaves similarly to another Rfa1 mutant (rfa1-t11) with respect to genetic interactions, DNA-damage sensitivity, and checkpoint adaptation. Our data indicate that post-translational modification of the Rfa2 N-terminus is not required for cells to deal with "repairable" DNA damage; however, post-translational modification of this domain might influence whether cells proceed into M-phase in the continued presence of unrepaired DNA lesions as a "last-resort" mechanism for cell survival.
Collapse
|
36
|
Maréchal A, Zou L. RPA-coated single-stranded DNA as a platform for post-translational modifications in the DNA damage response. Cell Res 2014; 25:9-23. [PMID: 25403473 DOI: 10.1038/cr.2014.147] [Citation(s) in RCA: 315] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The Replication Protein A (RPA) complex is an essential regulator of eukaryotic DNA metabolism. RPA avidly binds to single-stranded DNA (ssDNA) through multiple oligonucleotide/oligosaccharide-binding folds and coordinates the recruitment and exchange of genome maintenance factors to regulate DNA replication, recombination and repair. The RPA-ssDNA platform also constitutes a key physiological signal which activates the master ATR kinase to protect and repair stalled or collapsed replication forks during replication stress. In recent years, the RPA complex has emerged as a key target and an important regulator of post-translational modifications in response to DNA damage, which is critical for its genome guardian functions. Phosphorylation and SUMOylation of the RPA complex, and more recently RPA-regulated ubiquitination, have all been shown to control specific aspects of DNA damage signaling and repair by modulating the interactions between RPA and its partners. Here, we review our current understanding of the critical functions of the RPA-ssDNA platform in the maintenance of genome stability and its regulation through an elaborate network of covalent modifications.
Collapse
Affiliation(s)
- Alexandre Maréchal
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Lee Zou
- 1] Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA [2] Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| |
Collapse
|
37
|
Gao J, Wang H, Wong AHH, Zeng G, Huang Z, Wang Y, Sang J, Wang Y. Regulation of Rfa2 phosphorylation in response to genotoxic stress in Candida albicans. Mol Microbiol 2014; 94:141-55. [PMID: 25109320 DOI: 10.1111/mmi.12749] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2014] [Indexed: 01/10/2023]
Abstract
Successful pathogens must be able to swiftly respond to and repair DNA damages inflicted by the host defence. The replication protein A (RPA) complex plays multiple roles in DNA damage response and is regulated by phosphorylation. However, the regulators of RPA phosphorylation remain unclear. Here, we investigated Rfa2 phosphorylation in the pathogenic fungus Candida albicans. Rfa2, a RFA subunit, is phosphorylated when DNA replication is inhibited by hydroxyurea and dephosphorylated during the recovery. By screening a phosphatase mutant library, we found that Pph3 associates with different regulatory subunits to differentially control Rfa2 dephosphorylation in stressed and unstressed cells. Site-directed mutagenesis revealed T11, S18, S29, and S30 being critical for Rfa2 phosphorylation in response to genotoxic insult. We obtained evidence that the genome integrity checkpoint kinase Mec1 and the cyclin-dependent kinase Clb2-Cdc28 mediate Rfa2 phosphorylation. Although cells expressing either a phosphomimetic or a non-phosphorylatable version of Rfa2 had defects, the latter exhibited greater sensitivity to genotoxic challenge, failure to repair DNA damages and to deactivate Rad53-mediated checkpoint pathways in a dosage-dependent manner. These mutants were also less virulent in mice. Our results provide important new insights into the regulatory mechanism and biological significance of Rfa2 phosphorylation in C. albicans.
Collapse
Affiliation(s)
- Jiaxin Gao
- Key Laboratory of Cell Proliferation and Regulation Biology, College of Life Sciences, Beijing Normal University, Beijing, China; Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore
| | | | | | | | | | | | | | | |
Collapse
|
38
|
Interplay of DNA damage and cell cycle signaling at the level of human replication protein A. DNA Repair (Amst) 2014; 21:12-23. [PMID: 25091156 DOI: 10.1016/j.dnarep.2014.05.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 03/17/2014] [Accepted: 05/18/2014] [Indexed: 02/05/2023]
Abstract
Replication protein A (RPA) is the main human single-stranded DNA (ssDNA)-binding protein. It is essential for cellular DNA metabolism and has important functions in human cell cycle and DNA damage signaling. RPA is indispensable for accurate homologous recombination (HR)-based DNA double-strand break (DSB) repair and its activity is regulated by phosphorylation and other post-translational modifications. HR occurs only during S and G2 phases of the cell cycle. All three subunits of RPA contain phosphorylation sites but the exact set of HR-relevant phosphorylation sites on RPA is unknown. In this study, a high resolution capillary isoelectric focusing immunoassay, used under native conditions, revealed the isoforms of the RPA heterotrimer in control and damaged cell lysates in G2. Moreover, the phosphorylation sites of chromatin-bound and cytosolic RPA in S and G2 phases were identified by western and IEF analysis with all available phosphospecific antibodies for RPA2. Strikingly, most of the RPA heterotrimers in control G2 cells are phosphorylated with 5 isoforms containing up to 7 phosphates. These isoforms include RPA2 pSer23 and pSer33. DNA damaged cells in G2 had 9 isoforms with up to 14 phosphates. DNA damage isoforms contained pSer4/8, pSer12, pThr21, pSer23, and pSer33 on RPA2 and up to 8 unidentified phosphorylation sites.
Collapse
|
39
|
Regulation of LC3-dependent protective autophagy in ovarian cancer cells by protein phosphatase 2A. Int J Gynecol Cancer 2014; 23:630-41. [PMID: 23518861 DOI: 10.1097/igc.0b013e3182892cee] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
OBJECTIVE Protein phosphatase 2A (PP2A) is a target for cisplatin, which is a widely used platinum drug to treat various cancer, including ovarian cancer. However, to date, the exact role of PP2A in chemoresistance to cisplatin-centered ovarian cancer therapy is not clear. METHODS AND MATERIALS To analyze the function of PP2A in cisplatin-resistant ovarian cancer cells, we derived A2780/cisplatin (CDDP), which is resistant to cisplatin, from A2780 cell line. Western blotting was used to detect the expression of PP2A, autophagy, and apoptosis markers. RESULTS The expression of PP2A catalytic subunit, (PP2Ac) was reduced in A2780/CDDP as well as in cisplatin-resistant patients' tissues compared with A2780 and cisplatin-sensitive patients. In the A2780 cells, cisplatin induced both apoptosis and autophagy. Interestingly, however, the autophagy inhibitor 3-methyladenine increased the cell death induced by diamindichloridoplatin (DDP), which suggested the protective function of autophagy in DDP-induced cell death. Knocking down of PP2A promoted autophagy but suppressed DDP-induced apoptosis and cell death. In contrast, overexpression of PP2Ac or reinduction of the activity of PP2A by FTY720 decreased autophagy but increased cell death induced by DDP. Our experiments demonstrated that apoptosis suppressed by the knocking down of PP2Ac can be reversed by the administration of 3-methyladenine. The elevated accumulation of microtubule-associated protein 1 light chain 3-II and the decline of the autophagy substrate p62 were also observed in PP2Ac-small interfering RNA transfected cells. However, overexpression of PP2Ac suppressed the accumulation of microtubule-associated protein 1 light chain 3-II and restored p62. CONCLUSIONS Taken together, our results showed that protective autophagy regulated by PP2Ac is at least part of the mechanism to how certain ovarian cancers are resistant to cisplatin. Prospective studies are necessary to determine the detailed mechanism of how PP2Ac regulates autophagy in chemoresistant patients.
Collapse
|
40
|
Woods D, Turchi JJ. Chemotherapy induced DNA damage response: convergence of drugs and pathways. Cancer Biol Ther 2013. [PMID: 23380594 DOI: 10.4161/cbt23761] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/24/2023] Open
Abstract
Chemotherapeutics target rapidly dividing cancer cells by directly or indirectly inducing DNA damage. Upon recognizing DNA damage, cells initiate a variety of signaling pathways collectively referred to as the DNA damage response (DDR). Interestingly, the pathways used to elicit this response are as varied as the types of DNA damage induced. However, the activation of these various pathways has similar results including DNA repair, suppression of global general translation, cell cycle arrest and, ultimately, either cell survival or cell death. This review will focus on a series of chemotherapy-induced DNA lesions and highlight recent advances in our understanding of the DDR, the DNA repair pathways it activates and the cellular consequences of these converging pathways.
Collapse
Affiliation(s)
- Derek Woods
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA
| | | |
Collapse
|
41
|
Ashton NW, Bolderson E, Cubeddu L, O'Byrne KJ, Richard DJ. Human single-stranded DNA binding proteins are essential for maintaining genomic stability. BMC Mol Biol 2013; 14:9. [PMID: 23548139 PMCID: PMC3626794 DOI: 10.1186/1471-2199-14-9] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 03/20/2013] [Indexed: 12/25/2022] Open
Abstract
The double-stranded conformation of cellular DNA is a central aspect of DNA stabilisation and protection. The helix preserves the genetic code against chemical and enzymatic degradation, metabolic activation, and formation of secondary structures. However, there are various instances where single-stranded DNA is exposed, such as during replication or transcription, in the synthesis of chromosome ends, and following DNA damage. In these instances, single-stranded DNA binding proteins are essential for the sequestration and processing of single-stranded DNA. In order to bind single-stranded DNA, these proteins utilise a characteristic and evolutionary conserved single-stranded DNA-binding domain, the oligonucleotide/oligosaccharide-binding (OB)-fold. In the current review we discuss a subset of these proteins involved in the direct maintenance of genomic stability, an important cellular process in the conservation of cellular viability and prevention of malignant transformation. We discuss the central roles of single-stranded DNA binding proteins from the OB-fold domain family in DNA replication, the restart of stalled replication forks, DNA damage repair, cell cycle-checkpoint activation, and telomere maintenance.
Collapse
Affiliation(s)
- Nicholas W Ashton
- Genome Stability Laboratory, Cancer and Ageing Research Program, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Woolloongabba, Queensland, 4102, Australia
| | | | | | | | | |
Collapse
|
42
|
Abstract
Rfa2 is a ssDNA (single-stranded DNA)-binding protein that plays an important role in DNA replication, recombination and repair. Rfa2 is regulated by phosphorylation, which alters its protein–protein interaction and protein–DNA interaction. In the present study, we found that the Pph3–Psy2 phosphatase complex is responsible for Rfa2 dephosphorylation both during normal G1-phase and under DNA replication stress in Candida albicans. Phosphorylated Rfa2 extracted from pph3Δ or psy2Δ G1 cells exhibited diminished binding affinity to dsDNA (double-stranded DNA) but not to ssDNA. We also discovered that Cdc28 (cell division cycle 28) and Mec1 are responsible for Rfa2 phosphorylation in G1-phase and under DNA replication stress respectively. Moreover, MS revealed that the domain of Rfa2 that was phosphorylated in G1-phase differed from that phosphorylated under the stress conditions. The results of the present study imply that differential phosphorylation plays a crucial role in RPA (replication protein A) regulation.
Collapse
|
43
|
Abstract
Parvoviruses are a group of small DNA viruses with ssDNA genomes flanked by two inverted terminal structures. Due to a limited genetic resource they require host cellular factors and sometimes a helper virus for efficient viral replication. Recent studies have shown that parvoviruses interact with the DNA damage machinery, which has a significant impact on the life cycle of the virus as well as the fate of infected cells. In addition, due to special DNA structures of the viral genomes, parvoviruses are useful tools for the study of the molecular mechanisms underlying viral infection-induced DNA damage response (DDR). This review aims to summarize recent advances in parvovirus-induced DDR, with a focus on the diverse DDR pathways triggered by different parvoviruses and the consequences of DDR on the viral life cycle as well as the fate of infected cells.
Collapse
Affiliation(s)
- Yong Luo
- Department of Microbiology, Molecular Genetics & Immunology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Jianming Qiu
- Department of Microbiology, Molecular Genetics & Immunology, University of Kansas Medical Center, Kansas City, KS, USA
| |
Collapse
|
44
|
Woods D, Turchi JJ. Chemotherapy induced DNA damage response: convergence of drugs and pathways. Cancer Biol Ther 2013; 14:379-89. [PMID: 23380594 PMCID: PMC3672181 DOI: 10.4161/cbt.23761] [Citation(s) in RCA: 187] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Chemotherapeutics target rapidly dividing cancer cells by directly or indirectly inducing DNA damage. Upon recognizing DNA damage, cells initiate a variety of signaling pathways collectively referred to as the DNA damage response (DDR). Interestingly, the pathways used to elicit this response are as varied as the types of DNA damage induced. However, the activation of these various pathways has similar results including DNA repair, suppression of global general translation, cell cycle arrest and, ultimately, either cell survival or cell death. This review will focus on a series of chemotherapy-induced DNA lesions and highlight recent advances in our understanding of the DDR, the DNA repair pathways it activates and the cellular consequences of these converging pathways.
Collapse
Affiliation(s)
- Derek Woods
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA
| | | |
Collapse
|
45
|
Shimada M, Nakanishi M. Response to DNA damage: why do we need to focus on protein phosphatases? Front Oncol 2013; 3:8. [PMID: 23386996 PMCID: PMC3560363 DOI: 10.3389/fonc.2013.00008] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Accepted: 01/09/2013] [Indexed: 01/07/2023] Open
Abstract
Eukaryotic cells are continuously threatened by unavoidable errors during normal DNA replication or various sources of genotoxic stresses that cause DNA damage or stalled replication. To maintain genomic integrity, cells have developed a coordinated signaling network, known as the DNA damage response (DDR). Following DNA damage, sensor molecules detect the presence of DNA damage and transmit signals to downstream transducer molecules. This in turn conveys the signals to numerous effectors, which initiate a large number of specific biological responses, including transient cell cycle arrest mediated by checkpoints, DNA repair, and apoptosis. It is recently becoming clear that dephosphorylation events are involved in keeping DDR factors inactive during normal cell growth. Moreover, dephosphorylation is required to shut off checkpoint arrest following DNA damage and has been implicated in the activation of the DDR. Spatial and temporal regulation of phosphorylation events is essential for the DDR, and fine-tuning of phosphorylation is partly mediated by protein phosphatases. While the role of kinases in the DDR has been well documented, the complex roles of protein dephosphorylation have only recently begun to be investigated. Therefore, it is important to focus on the role of phosphatases and to determine how their activity is regulated upon DNA damage. In this work, we summarize current knowledge on the involvement of serine/threonine phosphatases, especially the protein phosphatase 1, protein phosphatase 2A, and protein phosphatase Mg2+/Mn2+-dependent families, in the DDR.
Collapse
Affiliation(s)
- Midori Shimada
- Department of Cell Biology, Graduate School of Medical Sciences, Nagoya City University Nagoya, Japan
| | | |
Collapse
|
46
|
Liu S, Opiyo SO, Manthey K, Glanzer JG, Ashley AK, Amerin C, Troksa K, Shrivastav M, Nickoloff JA, Oakley GG. Distinct roles for DNA-PK, ATM and ATR in RPA phosphorylation and checkpoint activation in response to replication stress. Nucleic Acids Res 2012; 40:10780-94. [PMID: 22977173 PMCID: PMC3510507 DOI: 10.1093/nar/gks849] [Citation(s) in RCA: 191] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
DNA damage encountered by DNA replication forks poses risks of genome destabilization, a
precursor to carcinogenesis. Damage checkpoint systems cause cell cycle arrest, promote
repair and induce programed cell death when damage is severe. Checkpoints are critical
parts of the DNA damage response network that act to suppress cancer. DNA damage and
perturbation of replication machinery causes replication stress, characterized by
accumulation of single-stranded DNA bound by replication protein A (RPA), which triggers
activation of ataxia telangiectasia and Rad3 related (ATR) and phosphorylation of the
RPA32, subunit of RPA, leading to Chk1 activation and arrest. DNA-dependent protein kinase
catalytic subunit (DNA-PKcs) [a kinase related to ataxia telangiectasia mutated (ATM) and
ATR] has well characterized roles in DNA double-strand break repair, but poorly understood
roles in replication stress-induced RPA phosphorylation. We show that DNA-PKcs mutant
cells fail to arrest replication following stress, and mutations in RPA32 phosphorylation
sites targeted by DNA-PKcs increase the proportion of cells in mitosis, impair ATR
signaling to Chk1 and confer a G2/M arrest defect. Inhibition of ATR and DNA-PK (but not
ATM), mimic the defects observed in cells expressing mutant RPA32. Cells expressing mutant
RPA32 or DNA-PKcs show sustained H2AX phosphorylation in response to replication stress
that persists in cells entering mitosis, indicating inappropriate mitotic entry with
unrepaired damage.
Collapse
Affiliation(s)
- Shengqin Liu
- Department of Oral Biology, University of Nebraska Medical Center, Omaha, NE 68583, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Hromas R, Williamson EA, Fnu S, Lee YJ, Park SJ, Beck BD, You JS, Leitao A, Laitao A, Nickoloff JA, Lee SH. Chk1 phosphorylation of Metnase enhances DNA repair but inhibits replication fork restart. Oncogene 2012; 31:4245-54. [PMID: 22231448 DOI: 10.1038/onc.2011.586] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Chk1 both arrests replication forks and enhances repair of DNA damage by phosphorylating downstream effectors. Although there has been a concerted effort to identify effectors of Chk1 activity, underlying mechanisms of effector action are still being identified. Metnase (also called SETMAR) is a SET and transposase domain protein that promotes both DNA double-strand break (DSB) repair and restart of stalled replication forks. In this study, we show that Metnase is phosphorylated only on Ser495 (S495) in vivo in response to DNA damage by ionizing radiation. Chk1 is the major mediator of this phosphorylation event. We had previously shown that wild-type (wt) Metnase associates with chromatin near DSBs and methylates histone H3 Lys36. Here we show that a Ser495Ala (S495A) Metnase mutant, which is not phosphorylated by Chk1, is defective in DSB-induced chromatin association. The S495A mutant also fails to enhance repair of an induced DSB when compared with wt Metnase. Interestingly, the S495A mutant demonstrated increased restart of stalled replication forks compared with wt Metnase. Thus, phosphorylation of Metnase S495 differentiates between these two functions, enhancing DSB repair and repressing replication fork restart. In summary, these data lend insight into the mechanism by which Chk1 enhances repair of DNA damage while at the same time repressing stalled replication fork restart.
Collapse
Affiliation(s)
- R Hromas
- Department of Medicine, University of Florida and Shands Health Care System, Gainesville, FL 32610, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Lui C, Mills K, Brocardo MG, Sharma M, Henderson BR. APC as a mobile scaffold: regulation and function at the nucleus, centrosomes, and mitochondria. IUBMB Life 2011; 64:209-14. [PMID: 22162224 DOI: 10.1002/iub.599] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 11/02/2011] [Indexed: 12/13/2022]
Abstract
Genetic mutations of adenomatous polyposis coli (APC) predispose to high risk of human colon cancer. APC is a large tumor suppressor protein and truncating mutations disrupt its normal roles in regulating cell migration, DNA replication/repair, mitosis, apoptosis, and turnover of oncogenic β-catenin. APC is targeted to multiple subcellular sites, and here we discuss recent evidence implicating novel protein interactions and functions of APC in the nucleus and at centrosomes and mitochondria. The ability of APC to shuttle between these and other cell locations is hypothesized to be integral to its cellular function.
Collapse
Affiliation(s)
- Christina Lui
- Westmead Institute for Cancer Research, University of Sydney, Westmead Millennium Institute at Westmead Hospital, New South Wales, Australia
| | | | | | | | | |
Collapse
|
49
|
Allen C, Ashley AK, Hromas R, Nickoloff JA. More forks on the road to replication stress recovery. J Mol Cell Biol 2011; 3:4-12. [PMID: 21278446 DOI: 10.1093/jmcb/mjq049] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
High-fidelity replication of DNA, and its accurate segregation to daughter cells, is critical for maintaining genome stability and suppressing cancer. DNA replication forks are stalled by many DNA lesions, activating checkpoint proteins that stabilize stalled forks. Stalled forks may eventually collapse, producing a broken DNA end. Fork restart is typically mediated by proteins initially identified by their roles in homologous recombination repair of DNA double-strand breaks (DSBs). In recent years, several proteins involved in DSB repair by non-homologous end joining (NHEJ) have been implicated in the replication stress response, including DNA-PKcs, Ku, DNA Ligase IV-XRCC4, Artemis, XLF and Metnase. It is currently unclear whether NHEJ proteins are involved in the replication stress response through indirect (signaling) roles, and/or direct roles involving DNA end joining. Additional complexity in the replication stress response centers around RPA, which undergoes significant post-translational modification after stress, and RAD52, a conserved HR protein whose role in DSB repair may have shifted to another protein in higher eukaryotes, such as BRCA2, but retained its role in fork restart. Most cancer therapeutic strategies create DNA replication stress. Thus, it is imperative to gain a better understanding of replication stress response proteins and pathways to improve cancer therapy.
Collapse
Affiliation(s)
- Chris Allen
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft Collins, CO 80523, USA
| | | | | | | |
Collapse
|
50
|
Brocardo MG, Borowiec JA, Henderson BR. Adenomatous polyposis coli protein regulates the cellular response to DNA replication stress. Int J Biochem Cell Biol 2011; 43:1354-64. [PMID: 21664290 DOI: 10.1016/j.biocel.2011.05.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 05/12/2011] [Accepted: 05/24/2011] [Indexed: 10/18/2022]
Abstract
The adenomatous polyposis coli (APC) tumor suppressor traffics between nucleus and cytoplasm to perform distinct functions. Here we identify a specific role for APC in the DNA replication stress response. The silencing of APC caused an accumulation of asynchronous cells in early S phase and delayed S phase progression in cells released from hydroxyurea-mediated replication arrest. Immunoprecipitation assays revealed a selective binding of APC to replication protein A 32kDa subunit (RPA32), and the APC-RPA32 complex increased at chromatin after hydroxyurea treatment. Interestingly, APC knock-down prevented accumulation at chromatin of the stress-induced S33- and S29-phosphorylated forms of RPA32, and reduced the expression of ATR-phosphorylated forms of S317-phospho-Chk1 and γ-H2AX. Using RPA32-inducible cells we showed that reconstitution of RPA32 diminished the S-phase delay caused by loss of APC. In contrast to full-length APC, the truncated APC mutant protein expressed in SW480 colon cancer cells was impaired in its binding and regulation of RPA32, and failed to regulate cell cycle after replication stress. We propose that APC associates with RPA at stalled DNA replication forks and promotes the ATR-dependent phosphorylation of RPA32, Chk1 and γ-H2AX in response to DNA replication stress, thereby influencing the rate of re-entry into the cell cycle.
Collapse
Affiliation(s)
- Mariana G Brocardo
- Westmead Institute for Cancer Research, University of Sydney, Westmead Millennium Institute at Westmead Hospital, Westmead, New South Wales 2145, Australia.
| | | | | |
Collapse
|