1
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Tacconi EMC, Badie S, De Gregoriis G, Reisländer T, Lai X, Porru M, Folio C, Moore J, Kopp A, Baguña Torres J, Sneddon D, Green M, Dedic S, Lee JW, Batra AS, Rueda OM, Bruna A, Leonetti C, Caldas C, Cornelissen B, Brino L, Ryan A, Biroccio A, Tarsounas M. Chlorambucil targets BRCA1/2-deficient tumours and counteracts PARP inhibitor resistance. EMBO Mol Med 2019; 11:e9982. [PMID: 31273933 PMCID: PMC6609913 DOI: 10.15252/emmm.201809982] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 04/30/2019] [Accepted: 05/03/2019] [Indexed: 01/03/2023] Open
Abstract
Due to compromised homologous recombination (HR) repair, BRCA1- and BRCA2-mutated tumours accumulate DNA damage and genomic rearrangements conducive of tumour progression. To identify drugs that target specifically BRCA2-deficient cells, we screened a chemical library containing compounds in clinical use. The top hit was chlorambucil, a bifunctional alkylating agent used for the treatment of chronic lymphocytic leukaemia (CLL). We establish that chlorambucil is specifically toxic to BRCA1/2-deficient cells, including olaparib-resistant and cisplatin-resistant ones, suggesting the potential clinical use of chlorambucil against disease which has become resistant to these drugs. Additionally, chlorambucil eradicates BRCA2-deficient xenografts and inhibits growth of olaparib-resistant patient-derived tumour xenografts (PDTXs). We demonstrate that chlorambucil inflicts replication-associated DNA double-strand breaks (DSBs), similarly to cisplatin, and we identify ATR, FANCD2 and the SNM1A nuclease as determinants of sensitivity to both drugs. Importantly, chlorambucil is substantially less toxic to normal cells and tissues in vitro and in vivo relative to cisplatin. Because chlorambucil and cisplatin are equally effective inhibitors of BRCA2-compromised tumours, our results indicate that chlorambucil has a higher therapeutic index than cisplatin in targeting BRCA-deficient tumours.
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MESH Headings
- Animals
- BRCA1 Protein/deficiency
- BRCA2 Protein/deficiency
- Cell Line, Tumor
- Chlorambucil/pharmacology
- Cricetinae
- Drug Delivery Systems
- Drug Resistance, Neoplasm/drug effects
- Drug Resistance, Neoplasm/genetics
- Humans
- Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy
- Leukemia, Lymphocytic, Chronic, B-Cell/genetics
- Leukemia, Lymphocytic, Chronic, B-Cell/metabolism
- Male
- Mice
- Mice, SCID
- Peroxisome Proliferator-Activated Receptors/antagonists & inhibitors
- Peroxisome Proliferator-Activated Receptors/metabolism
- Phthalazines/pharmacology
- Piperazines/pharmacology
- Xenograft Model Antitumor Assays
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Affiliation(s)
- Eliana MC Tacconi
- Genome Stability and Tumorigenesis GroupDepartment of OncologyThe CR‐UK/MRC Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Sophie Badie
- Genome Stability and Tumorigenesis GroupDepartment of OncologyThe CR‐UK/MRC Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Giuliana De Gregoriis
- Genome Stability and Tumorigenesis GroupDepartment of OncologyThe CR‐UK/MRC Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Timo Reisländer
- Genome Stability and Tumorigenesis GroupDepartment of OncologyThe CR‐UK/MRC Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Xianning Lai
- Genome Stability and Tumorigenesis GroupDepartment of OncologyThe CR‐UK/MRC Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Manuela Porru
- Area of Translational ResearchIRCCS Regina Elena National Cancer InstituteRomeItaly
| | - Cecilia Folio
- Genome Stability and Tumorigenesis GroupDepartment of OncologyThe CR‐UK/MRC Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - John Moore
- Lung Cancer Translational Science Research GroupDepartment of OncologyThe CR‐UK/MRC Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Arnaud Kopp
- Institut de Génétique et de Biologie Cellulaire et Moléculaire (IGBMC)Inserm U1258, CNRS (UMR 7104)Université de StrasbourgIllkirchFrance
| | - Júlia Baguña Torres
- Radiopharmaceuticals and Molecular Imaging GroupDepartment of OncologyThe CR‐UK/MRC Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Deborah Sneddon
- Radiopharmaceuticals and Molecular Imaging GroupDepartment of OncologyThe CR‐UK/MRC Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Marcus Green
- Lung Cancer Translational Science Research GroupDepartment of OncologyThe CR‐UK/MRC Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Simon Dedic
- Genome Stability and Tumorigenesis GroupDepartment of OncologyThe CR‐UK/MRC Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Jonathan W Lee
- Genome Stability and Tumorigenesis GroupDepartment of OncologyThe CR‐UK/MRC Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Ankita Sati Batra
- Department of OncologyCancer Research UK Cambridge InstituteUniversity of CambridgeCambridgeUK
| | - Oscar M Rueda
- Department of OncologyCancer Research UK Cambridge InstituteUniversity of CambridgeCambridgeUK
| | - Alejandra Bruna
- Department of OncologyCancer Research UK Cambridge InstituteUniversity of CambridgeCambridgeUK
| | - Carlo Leonetti
- Area of Translational ResearchIRCCS Regina Elena National Cancer InstituteRomeItaly
| | - Carlos Caldas
- Department of OncologyCancer Research UK Cambridge InstituteUniversity of CambridgeCambridgeUK
| | - Bart Cornelissen
- Radiopharmaceuticals and Molecular Imaging GroupDepartment of OncologyThe CR‐UK/MRC Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Laurent Brino
- Institut de Génétique et de Biologie Cellulaire et Moléculaire (IGBMC)Inserm U1258, CNRS (UMR 7104)Université de StrasbourgIllkirchFrance
| | - Anderson Ryan
- Lung Cancer Translational Science Research GroupDepartment of OncologyThe CR‐UK/MRC Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Annamaria Biroccio
- Area of Translational ResearchIRCCS Regina Elena National Cancer InstituteRomeItaly
| | - Madalena Tarsounas
- Genome Stability and Tumorigenesis GroupDepartment of OncologyThe CR‐UK/MRC Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
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2
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Tacconi EM, Lai X, Folio C, Porru M, Zonderland G, Badie S, Michl J, Sechi I, Rogier M, Matía García V, Batra AS, Rueda OM, Bouwman P, Jonkers J, Ryan A, Reina-San-Martin B, Hui J, Tang N, Bruna A, Biroccio A, Tarsounas M. BRCA1 and BRCA2 tumor suppressors protect against endogenous acetaldehyde toxicity. EMBO Mol Med 2018; 9:1398-1414. [PMID: 28729482 PMCID: PMC5623864 DOI: 10.15252/emmm.201607446] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Maintenance of genome integrity requires the functional interplay between Fanconi anemia (FA) and homologous recombination (HR) repair pathways. Endogenous acetaldehyde, a product of cellular metabolism, is a potent source of DNA damage, particularly toxic to cells and mice lacking the FA protein FANCD2. Here, we investigate whether HR-compromised cells are sensitive to acetaldehyde, similarly to FANCD2-deficient cells. We demonstrate that inactivation of HR factors BRCA1, BRCA2, or RAD51 hypersensitizes cells to acetaldehyde treatment, in spite of the FA pathway being functional. Aldehyde dehydrogenases (ALDHs) play key roles in endogenous acetaldehyde detoxification, and their chemical inhibition leads to cellular acetaldehyde accumulation. We find that disulfiram (Antabuse), an ALDH2 inhibitor in widespread clinical use for the treatment of alcoholism, selectively eliminates BRCA1/2-deficient cells. Consistently, Aldh2 gene inactivation suppresses proliferation of HR-deficient mouse embryonic fibroblasts (MEFs) and human fibroblasts. Hypersensitivity of cells lacking BRCA2 to acetaldehyde stems from accumulation of toxic replication-associated DNA damage, leading to checkpoint activation, G2/M arrest, and cell death. Acetaldehyde-arrested replication forks require BRCA2 and FANCD2 for protection against MRE11-dependent degradation. Importantly, acetaldehyde specifically inhibits in vivo the growth of BRCA1/2-deficient tumors and ex vivo in patient-derived tumor xenograft cells (PDTCs), including those that are resistant to poly (ADP-ribose) polymerase (PARP) inhibitors. The work presented here therefore identifies acetaldehyde metabolism as a potential therapeutic target for the selective elimination of BRCA1/2-deficient cells and tumors.
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Affiliation(s)
- Eliana Mc Tacconi
- Department of Oncology, Genome Stability and Tumorigenesis Group, The CR-UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, UK
| | - Xianning Lai
- Department of Oncology, Genome Stability and Tumorigenesis Group, The CR-UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, UK
| | - Cecilia Folio
- Department of Oncology, Genome Stability and Tumorigenesis Group, The CR-UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, UK
| | - Manuela Porru
- Area of Translational Research, Regina Elena National Cancer Institute, Rome, Italy
| | - Gijs Zonderland
- Department of Oncology, Genome Stability and Tumorigenesis Group, The CR-UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, UK
| | - Sophie Badie
- Department of Oncology, Genome Stability and Tumorigenesis Group, The CR-UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, UK
| | - Johanna Michl
- Department of Oncology, Genome Stability and Tumorigenesis Group, The CR-UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, UK
| | - Irene Sechi
- Department of Oncology, Genome Stability and Tumorigenesis Group, The CR-UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, UK
| | - Mélanie Rogier
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), U964, Illkirch, France.,Centre National de Recherche Scientifique (CNRS), UMR7104, Illkirch, France.,Université de Strasbourg, Illkirch, France
| | - Verónica Matía García
- Division of Molecular Pathology and Cancer Genomics Netherlands, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | | | - Oscar M Rueda
- Cancer Research UK Cambridge Institute, Cambridge, UK
| | - Peter Bouwman
- Division of Molecular Pathology and Cancer Genomics Netherlands, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Jos Jonkers
- Division of Molecular Pathology and Cancer Genomics Netherlands, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Anderson Ryan
- Department of Oncology, Lung Cancer Translational Science Research Group, The CR-UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, UK
| | - Bernardo Reina-San-Martin
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), U964, Illkirch, France.,Centre National de Recherche Scientifique (CNRS), UMR7104, Illkirch, France.,Université de Strasbourg, Illkirch, France
| | - Joannie Hui
- Department of Chemical Pathology and Paediatrics, Faculty of Medicine, Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Nelson Tang
- Department of Chemical Pathology and Paediatrics, Faculty of Medicine, Chinese University of Hong Kong, Shatin, Hong Kong, China
| | | | - Annamaria Biroccio
- Area of Translational Research, Regina Elena National Cancer Institute, Rome, Italy
| | - Madalena Tarsounas
- Department of Oncology, Genome Stability and Tumorigenesis Group, The CR-UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, UK
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3
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Lai X, Broderick R, Bergoglio V, Zimmer J, Badie S, Niedzwiedz W, Hoffmann JS, Tarsounas M. Corrigendum: MUS81 nuclease activity is essential for replication stress tolerance and chromosome segregation in BRCA2-deficient cells. Nat Commun 2017; 8:16171. [PMID: 29072253 PMCID: PMC5659046 DOI: 10.1038/ncomms16171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
This corrects the article DOI: 10.1038/ncomms15983.
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4
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Lai X, Broderick R, Bergoglio V, Zimmer J, Badie S, Niedzwiedz W, Hoffmann JS, Tarsounas M. MUS81 nuclease activity is essential for replication stress tolerance and chromosome segregation in BRCA2-deficient cells. Nat Commun 2017; 8:15983. [PMID: 28714477 PMCID: PMC5520020 DOI: 10.1038/ncomms15983] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 05/17/2017] [Indexed: 11/28/2022] Open
Abstract
Failure to restart replication forks stalled at genomic regions that are difficult to replicate or contain endogenous DNA lesions is a hallmark of BRCA2 deficiency. The nucleolytic activity of MUS81 endonuclease is required for replication fork restart under replication stress elicited by exogenous treatments. Here we investigate whether MUS81 could similarly facilitate DNA replication in the context of BRCA2 abrogation. Our results demonstrate that replication fork progression in BRCA2-deficient cells requires MUS81. Failure to complete genome replication and defective checkpoint surveillance enables BRCA2-deficient cells to progress through mitosis with under-replicated DNA, which elicits severe chromosome interlinking in anaphase. MUS81 nucleolytic activity is required to activate compensatory DNA synthesis during mitosis and to resolve mitotic interlinks, thus facilitating chromosome segregation. We propose that MUS81 provides a mechanism of replication stress tolerance, which sustains survival of BRCA2-deficient cells and can be exploited therapeutically through development of specific inhibitors of MUS81 nuclease activity.
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Affiliation(s)
- Xianning Lai
- Genome Stability and Tumourigenesis Group, Department of Oncology, The CR-UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Ronan Broderick
- Division of Cancer Biology, Institute of Cancer Research, 123 Old Brompton Road, London SW7 3RP, UK
| | - Valérie Bergoglio
- Cancer Research Center of Toulouse, Université de Toulouse, Inserm, CNRS, UPS, Equipe labellisée Ligue Contre le Cancer, Laboratoire d’excellence Toulouse Cancer, 2 Avenue Hubert Curien, Toulouse 31037, France
| | - Jutta Zimmer
- Genome Stability and Tumourigenesis Group, Department of Oncology, The CR-UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Sophie Badie
- Genome Stability and Tumourigenesis Group, Department of Oncology, The CR-UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Wojciech Niedzwiedz
- Division of Cancer Biology, Institute of Cancer Research, 123 Old Brompton Road, London SW7 3RP, UK
| | - Jean-Sébastien Hoffmann
- Cancer Research Center of Toulouse, Université de Toulouse, Inserm, CNRS, UPS, Equipe labellisée Ligue Contre le Cancer, Laboratoire d’excellence Toulouse Cancer, 2 Avenue Hubert Curien, Toulouse 31037, France
| | - Madalena Tarsounas
- Genome Stability and Tumourigenesis Group, Department of Oncology, The CR-UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
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5
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Zimmer J, Tacconi EMC, Folio C, Badie S, Porru M, Klare K, Tumiati M, Markkanen E, Halder S, Ryan A, Jackson SP, Ramadan K, Kuznetsov SG, Biroccio A, Sale JE, Tarsounas M. Targeting BRCA1 and BRCA2 Deficiencies with G-Quadruplex-Interacting Compounds. Mol Cell 2016; 61:449-460. [PMID: 26748828 PMCID: PMC4747901 DOI: 10.1016/j.molcel.2015.12.004] [Citation(s) in RCA: 170] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 09/17/2015] [Accepted: 11/02/2015] [Indexed: 12/29/2022]
Abstract
G-quadruplex (G4)-forming genomic sequences, including telomeres, represent natural replication fork barriers. Stalled replication forks can be stabilized and restarted by homologous recombination (HR), which also repairs DNA double-strand breaks (DSBs) arising at collapsed forks. We have previously shown that HR facilitates telomere replication. Here, we demonstrate that the replication efficiency of guanine-rich (G-rich) telomeric repeats is decreased significantly in cells lacking HR. Treatment with the G4-stabilizing compound pyridostatin (PDS) increases telomere fragility in BRCA2-deficient cells, suggesting that G4 formation drives telomere instability. Remarkably, PDS reduces proliferation of HR-defective cells by inducing DSB accumulation, checkpoint activation, and deregulated G2/M progression and by enhancing the replication defect intrinsic to HR deficiency. PDS toxicity extends to HR-defective cells that have acquired olaparib resistance through loss of 53BP1 or REV7. Altogether, these results highlight the therapeutic potential of G4-stabilizing drugs to selectively eliminate HR-compromised cells and tumors, including those resistant to PARP inhibition.
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Affiliation(s)
- Jutta Zimmer
- Genome Stability and Tumourigenesis Group, CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Eliana M C Tacconi
- Genome Stability and Tumourigenesis Group, CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Cecilia Folio
- Genome Stability and Tumourigenesis Group, CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Sophie Badie
- Genome Stability and Tumourigenesis Group, CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Manuela Porru
- Area of Translational Research, Regina Elena National Cancer Institute, 00144 Rome, Italy
| | - Kerstin Klare
- Genome Stability and Tumourigenesis Group, CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Manuela Tumiati
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, P.O. Box 20, FIN-00014 Helsinki, Finland
| | - Enni Markkanen
- Biochemistry and Regulation of DNA Repair Group, CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Swagata Halder
- DNA Damage and Repair Group, CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Anderson Ryan
- Lung Cancer Translational Science Research Group, CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Stephen P Jackson
- The Gurdon Institute, CRUK Laboratories, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK; The Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - Kristijan Ramadan
- DNA Damage and Repair Group, CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Sergey G Kuznetsov
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, P.O. Box 20, FIN-00014 Helsinki, Finland
| | - Annamaria Biroccio
- Area of Translational Research, Regina Elena National Cancer Institute, 00144 Rome, Italy
| | - Julian E Sale
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Madalena Tarsounas
- Genome Stability and Tumourigenesis Group, CRUK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK.
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6
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Badie S, Carlos AR, Folio C, Okamoto K, Bouwman P, Jonkers J, Tarsounas M. BRCA1 and CtIP promote alternative non-homologous end-joining at uncapped telomeres. EMBO J 2015; 34:828. [PMID: 25766694 DOI: 10.15252/embj.201570610] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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7
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Badie S, Carlos AR, Folio C, Okamoto K, Bouwman P, Jonkers J, Tarsounas M. BRCA1 and CtIP promote alternative non-homologous end-joining at uncapped telomeres. EMBO J 2015; 34:410-24. [PMID: 25582120 PMCID: PMC4339125 DOI: 10.15252/embj.201488947] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 10/29/2014] [Accepted: 11/25/2014] [Indexed: 12/15/2022] Open
Abstract
Loss of telomere protection occurs during physiological cell senescence and ageing, due to attrition of telomeric repeats and insufficient retention of the telomere-binding factor TRF2. Subsequently formed telomere fusions trigger rampant genomic instability leading to cell death or tumorigenesis. Mechanistically, telomere fusions require either the classical non-homologous end-joining (C-NHEJ) pathway dependent on Ku70/80 and LIG4, or the alternative non-homologous end-joining (A-NHEJ), which relies on PARP1 and LIG3. Here, we show that the tumour suppressor BRCA1, together with its interacting partner CtIP, both acting in end resection, also promotes end-joining of uncapped telomeres. BRCA1 and CtIP do not function in the ATM-dependent telomere damage signalling, nor in telomere overhang removal, which are critical for telomere fusions by C-NHEJ. Instead, BRCA1 and CtIP act in the same pathway as LIG3 to promote joining of de-protected telomeres by A-NHEJ. Our work therefore ascribes novel roles for BRCA1 and CtIP in end-processing and fusion reactions at uncapped telomeres, underlining the complexity of DNA repair pathways that act at chromosome ends lacking protective structures. Moreover, A-NHEJ provides a mechanism of previously unanticipated significance in telomere dysfunction-induced genome instability.
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Affiliation(s)
- Sophie Badie
- Telomere and Genome Stability Group, The CR-UK/MRC Gray Institute for Radiation Oncology and Biology, Oxford, UK
| | - Ana Rita Carlos
- Telomere and Genome Stability Group, The CR-UK/MRC Gray Institute for Radiation Oncology and Biology, Oxford, UK
| | - Cecilia Folio
- Telomere and Genome Stability Group, The CR-UK/MRC Gray Institute for Radiation Oncology and Biology, Oxford, UK
| | - Keiji Okamoto
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Peter Bouwman
- Division of Molecular Pathology and Cancer Systems Biology Centre, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Jos Jonkers
- Division of Molecular Pathology and Cancer Systems Biology Centre, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Madalena Tarsounas
- Telomere and Genome Stability Group, The CR-UK/MRC Gray Institute for Radiation Oncology and Biology, Oxford, UK
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8
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Carlos AR, Escandell JM, Kotsantis P, Suwaki N, Bouwman P, Badie S, Folio C, Benitez J, Gomez-Lopez G, Pisano DG, Jonkers J, Tarsounas M. ARF triggers senescence in Brca2-deficient cells by altering the spectrum of p53 transcriptional targets. Nat Commun 2013; 4:2697. [PMID: 24162189 DOI: 10.1038/ncomms3697] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 10/02/2013] [Indexed: 01/12/2023] Open
Abstract
ARF is a tumour suppressor activated by oncogenic stress, which stabilizes p53. Although p53 is a key component of the response to DNA damage, a similar function for ARF has not been ascribed. Here we show that primary mouse and human cells lacking the tumour suppressor BRCA2 accumulate DNA damage, which triggers checkpoint signalling and ARF activation. Furthermore, senescence induced by Brca2 deletion in primary mouse and human cells is reversed by the loss of ARF, a phenotype recapitulated in cells lacking RAD51. Surprisingly, ARF is not necessary for p53 accumulation per se but for altering the spectrum of genes activated by this transcription factor. Specifically, ARF enables p53 transcription of Dusp4 and Dusp7, which encode a pair of phosphatases known to inactivate the MAP kinases ERK1/2. Our results ascribe a previously unanticipated function to the ARF tumour suppressor in genome integrity, controlled by replicative stress and ATM/ATR-dependent checkpoint responses.
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Affiliation(s)
- Ana Rita Carlos
- 1] Telomere and Genome Stability Group, The CR-UK/MRC Gray Institute for Radiation Oncology and Biology, Old Campus Road, Oxford OX3 7DQ, UK [2] [3]
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9
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Thanasoula M, Escandell JM, Martinez P, Badie S, Muñoz P, Blasco MA, Tarsounas M. p53 prevents entry into mitosis with uncapped telomeres. Curr Biol 2010; 20:521-6. [PMID: 20226664 DOI: 10.1016/j.cub.2010.01.046] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 01/12/2010] [Accepted: 01/14/2010] [Indexed: 02/01/2023]
Abstract
Telomeres are protected by capping structures consisting of core protein complexes that bind with sequence specificity to telomeric DNA. In their absence, telomeres trigger a DNA damage response, materialized in accumulation at the telomere of damage response proteins, e.g., phosphorylated histone H2AX (gammaH2AX), into telomere-dysfunction-induced foci. Telomere uncapping occurs transiently in every cell cycle in G2, following DNA replication, but little is known about how protective structures are reassembled or whether this process is controlled by the cell-cycle surveillance machinery. Here, we report that telomere capping is monitored at the G2/M transition by the p53/p21 damage response pathway. Unlike their wild-type counterparts, human and mouse cells lacking p53 or p21 progress into mitosis prematurely with persisting uncapped telomeres. Furthermore, artificially uncapped telomeres delay mitotic entry in a p53- and p21-dependent manner. Uncapped telomeres that persist in mitotic p53-deficient cells are shorter than average and religate to generate end-to-end fusions. These results suggest that a p53-dependent pathway monitors telomere capping after DNA replication and delays G2/M progression in the presence of unprotected telomeres. This mechanism maintains a cell-cycle stage conducive for capping reactions and prevents progression into stages during which uncapped telomeres are prone to deleterious end fusions.
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Affiliation(s)
- Maria Thanasoula
- Telomere and Genome Stability Group, The CR-UK/MRC Gray Institute for Radiation Oncology and Biology, Old Road Campus, Oxford OX37DQ, UK
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10
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Abstract
The RAD51 paralogues act in the homologous recombination (HR) pathway of DNA repair. Human RAD51C (hRAD51C) participates in branch migration and Holliday junction resolution and thus is important for processing HR intermediates late in the DNA repair process. Evidence for early involvement of RAD51 during DNA repair also exists, but its function in this context is not understood. In this study, we demonstrate that RAD51C accumulates at DNA damage sites concomitantly with the RAD51 recombinase and is retained after RAD51 disassembly, which is consistent with both an early and a late function for RAD51C. RAD51C recruitment depends on ataxia telangiectasia mutated, NBS1, and replication protein A, indicating it functions after DNA end resection but before RAD51 assembly. Furthermore, we find that RAD51C is required for activation of the checkpoint kinase CHK2 and cell cycle arrest in response to DNA damage. This suggests that hRAD51C contributes to the protection of genome integrity by transducing DNA damage signals in addition to engaging the HR machinery.
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Affiliation(s)
- Sophie Badie
- Cancer Research UK/Medical Research Council Gray Institute for Radiation Oncology and Biology, University of Oxford, Oxford OX3 7DQ, England, UK
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