1
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Dunce JM, Davies OR. BRCA2 stabilises RAD51 and DMC1 nucleoprotein filaments through a conserved interaction mode. Nat Commun 2024; 15:8292. [PMID: 39333100 PMCID: PMC11436757 DOI: 10.1038/s41467-024-52699-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 09/18/2024] [Indexed: 09/29/2024] Open
Abstract
BRCA2 is essential for DNA repair by homologous recombination in mitosis and meiosis. It interacts with recombinases RAD51 and DMC1 to facilitate the formation of nucleoprotein filaments on resected DNA ends that catalyse recombination-mediated repair. BRCA2's BRC repeats bind and disrupt RAD51 and DMC1 filaments, whereas its PhePP motifs bind recombinases and stabilise their nucleoprotein filaments. However, the mechanism of filament stabilisation has hitherto remained unknown. Here, we report the crystal structure of a BRCA2-DMC1 complex, revealing how core interaction sites of PhePP motifs bind to recombinases. The interaction mode is conserved for RAD51 and DMC1, which selectively bind to BRCA2's two distinct PhePP motifs via subtly divergent binding pockets. PhePP motif sequences surrounding their core interaction sites protect nucleoprotein filaments from BRC-mediated disruption. Hence, we report the structural basis of how BRCA2's PhePP motifs stabilise RAD51 and DMC1 nucleoprotein filaments for their essential roles in mitotic and meiotic recombination.
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Affiliation(s)
- James M Dunce
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Owen R Davies
- Wellcome Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, UK.
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2
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Schreuder A, Wendel TJ, Dorresteijn CGV, Noordermeer SM. (Single-stranded DNA) gaps in understanding BRCAness. Trends Genet 2024; 40:757-771. [PMID: 38789375 DOI: 10.1016/j.tig.2024.04.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 05/26/2024]
Abstract
The tumour-suppressive roles of BRCA1 and 2 have been attributed to three seemingly distinct functions - homologous recombination, replication fork protection, and single-stranded (ss)DNA gap suppression - and their relative importance is under debate. In this review, we examine the origin and resolution of ssDNA gaps and discuss the recent advances in understanding the role of BRCA1/2 in gap suppression. There are ample data showing that gap accumulation in BRCA1/2-deficient cells is linked to genomic instability and chemosensitivity. However, it remains unclear whether there is a causative role and the function of BRCA1/2 in gap suppression cannot unambiguously be dissected from their other functions. We therefore conclude that the three functions of BRCA1 and 2 are closely intertwined and not mutually exclusive.
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Affiliation(s)
- Anne Schreuder
- Leiden University Medical Center, Department of Human Genetics, Leiden, The Netherlands; Oncode Institute, Utrecht, The Netherlands
| | - Tiemen J Wendel
- Leiden University Medical Center, Department of Human Genetics, Leiden, The Netherlands; Oncode Institute, Utrecht, The Netherlands
| | - Carlo G V Dorresteijn
- Leiden University Medical Center, Department of Human Genetics, Leiden, The Netherlands
| | - Sylvie M Noordermeer
- Leiden University Medical Center, Department of Human Genetics, Leiden, The Netherlands; Oncode Institute, Utrecht, The Netherlands.
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3
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Gurusaran M, Zhang J, Zhang K, Shibuya H, Davies OR. MEILB2-BRME1 forms a V-shaped DNA clamp upon BRCA2-binding in meiotic recombination. Nat Commun 2024; 15:6552. [PMID: 39095423 PMCID: PMC11297322 DOI: 10.1038/s41467-024-50920-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 07/24/2024] [Indexed: 08/04/2024] Open
Abstract
DNA double-strand break repair by homologous recombination has a specialised role in meiosis by generating crossovers that enable the formation of haploid germ cells. This requires meiosis-specific MEILB2-BRME1, which interacts with BRCA2 to facilitate loading of recombinases onto resected DNA ends. Here, we report the crystal structure of the MEILB2-BRME1 2:2 core complex, revealing a parallel four-helical assembly that recruits BRME1 to meiotic double-strand breaks in vivo. It forms an N-terminal β-cap that binds to DNA, and a MEILB2 coiled-coil that bridges to C-terminal ARM domains. Upon BRCA2-binding, MEILB2-BRME1 2:2 complexes dimerize into a V-shaped 2:4:4 complex, with rod-like MEILB2-BRME1 components arranged at right-angles. The β-caps located at the tips of the MEILB2-BRME1 limbs are separated by 25 nm, allowing them to bridge between DNA molecules. Thus, we propose that BRCA2 induces MEILB2-BRME1 to function as a DNA clamp, connecting resected DNA ends or homologous chromosomes to facilitate meiotic recombination.
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Affiliation(s)
- Manickam Gurusaran
- Wellcome Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Jingjing Zhang
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Kexin Zhang
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Hiroki Shibuya
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
- Laboratory for Gametogenesis, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Hyogo, Japan
| | - Owen R Davies
- Wellcome Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh, UK.
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4
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Kong LR, Gupta K, Wu AJ, Perera D, Ivanyi-Nagy R, Ahmed SM, Tan TZ, Tan SLW, Fuddin A, Sundaramoorthy E, Goh GS, Wong RTX, Costa ASH, Oddy C, Wong H, Patro CPK, Kho YS, Huang XZ, Choo J, Shehata M, Lee SC, Goh BC, Frezza C, Pitt JJ, Venkitaraman AR. A glycolytic metabolite bypasses "two-hit" tumor suppression by BRCA2. Cell 2024; 187:2269-2287.e16. [PMID: 38608703 DOI: 10.1016/j.cell.2024.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 02/01/2024] [Accepted: 03/07/2024] [Indexed: 04/14/2024]
Abstract
Knudson's "two-hit" paradigm posits that carcinogenesis requires inactivation of both copies of an autosomal tumor suppressor gene. Here, we report that the glycolytic metabolite methylglyoxal (MGO) transiently bypasses Knudson's paradigm by inactivating the breast cancer suppressor protein BRCA2 to elicit a cancer-associated, mutational single-base substitution (SBS) signature in nonmalignant mammary cells or patient-derived organoids. Germline monoallelic BRCA2 mutations predispose to these changes. An analogous SBS signature, again without biallelic BRCA2 inactivation, accompanies MGO accumulation and DNA damage in Kras-driven, Brca2-mutant murine pancreatic cancers and human breast cancers. MGO triggers BRCA2 proteolysis, temporarily disabling BRCA2's tumor suppressive functions in DNA repair and replication, causing functional haploinsufficiency. Intermittent MGO exposure incites episodic SBS mutations without permanent BRCA2 inactivation. Thus, a metabolic mechanism wherein MGO-induced BRCA2 haploinsufficiency transiently bypasses Knudson's two-hit requirement could link glycolysis activation by oncogenes, metabolic disorders, or dietary challenges to mutational signatures implicated in cancer evolution.
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Affiliation(s)
- Li Ren Kong
- Cancer Science Institute of Singapore, Singapore 117599, Singapore; NUS Centre for Cancer Research (N2CR), National University of Singapore, Singapore 117599, Singapore; MRC Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK; Department of Pharmacology, National University of Singapore, Singapore 117600, Singapore
| | - Komal Gupta
- Cancer Science Institute of Singapore, Singapore 117599, Singapore; MRC Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK
| | - Andy Jialun Wu
- Cancer Science Institute of Singapore, Singapore 117599, Singapore
| | - David Perera
- MRC Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK
| | | | - Syed Moiz Ahmed
- Cancer Science Institute of Singapore, Singapore 117599, Singapore
| | - Tuan Zea Tan
- Cancer Science Institute of Singapore, Singapore 117599, Singapore
| | - Shawn Lu-Wen Tan
- MRC Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK; Institute of Molecular and Cell Biology (IMCB), A(∗)STAR, Singapore 138673, Singapore
| | | | | | | | | | - Ana S H Costa
- MRC Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK
| | - Callum Oddy
- Department of Oncology, University of Cambridge, Cambridge CB2 0XZ, UK
| | - Hannan Wong
- Cancer Science Institute of Singapore, Singapore 117599, Singapore
| | - C Pawan K Patro
- Cancer Science Institute of Singapore, Singapore 117599, Singapore
| | - Yun Suen Kho
- Cancer Science Institute of Singapore, Singapore 117599, Singapore; NUS Centre for Cancer Research (N2CR), National University of Singapore, Singapore 117599, Singapore
| | - Xiao Zi Huang
- Cancer Science Institute of Singapore, Singapore 117599, Singapore; NUS Centre for Cancer Research (N2CR), National University of Singapore, Singapore 117599, Singapore
| | - Joan Choo
- Department of Medicine, National University of Singapore, Singapore 119228, Singapore
| | - Mona Shehata
- MRC Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK; Department of Oncology, University of Cambridge, Cambridge CB2 0XZ, UK
| | - Soo Chin Lee
- Cancer Science Institute of Singapore, Singapore 117599, Singapore; NUS Centre for Cancer Research (N2CR), National University of Singapore, Singapore 117599, Singapore; Department of Medicine, National University of Singapore, Singapore 119228, Singapore
| | - Boon Cher Goh
- Cancer Science Institute of Singapore, Singapore 117599, Singapore; NUS Centre for Cancer Research (N2CR), National University of Singapore, Singapore 117599, Singapore; Department of Medicine, National University of Singapore, Singapore 119228, Singapore
| | - Christian Frezza
- MRC Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK; University of Cologne, 50923 Köln, Germany
| | - Jason J Pitt
- Cancer Science Institute of Singapore, Singapore 117599, Singapore; NUS Centre for Cancer Research (N2CR), National University of Singapore, Singapore 117599, Singapore; Genome Institute of Singapore, A(∗)STAR, Singapore 138673, Singapore
| | - Ashok R Venkitaraman
- Cancer Science Institute of Singapore, Singapore 117599, Singapore; NUS Centre for Cancer Research (N2CR), National University of Singapore, Singapore 117599, Singapore; MRC Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK; Institute of Molecular and Cell Biology (IMCB), A(∗)STAR, Singapore 138673, Singapore; Department of Oncology, University of Cambridge, Cambridge CB2 0XZ, UK; Department of Medicine, National University of Singapore, Singapore 119228, Singapore.
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5
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van de Kooij B, Schreuder A, Pavani R, Garzero V, Uruci S, Wendel TJ, van Hoeck A, San Martin Alonso M, Everts M, Koerse D, Callen E, Boom J, Mei H, Cuppen E, Luijsterburg MS, van Vugt MATM, Nussenzweig A, van Attikum H, Noordermeer SM. EXO1 protects BRCA1-deficient cells against toxic DNA lesions. Mol Cell 2024; 84:659-674.e7. [PMID: 38266640 DOI: 10.1016/j.molcel.2023.12.039] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 10/14/2023] [Accepted: 12/22/2023] [Indexed: 01/26/2024]
Abstract
Inactivating mutations in the BRCA1 and BRCA2 genes impair DNA double-strand break (DSB) repair by homologous recombination (HR), leading to chromosomal instability and cancer. Importantly, BRCA1/2 deficiency also causes therapeutically targetable vulnerabilities. Here, we identify the dependency on the end resection factor EXO1 as a key vulnerability of BRCA1-deficient cells. EXO1 deficiency generates poly(ADP-ribose)-decorated DNA lesions during S phase that associate with unresolved DSBs and genomic instability in BRCA1-deficient but not in wild-type or BRCA2-deficient cells. Our data indicate that BRCA1/EXO1 double-deficient cells accumulate DSBs due to impaired repair by single-strand annealing (SSA) on top of their HR defect. In contrast, BRCA2-deficient cells retain SSA activity in the absence of EXO1 and hence tolerate EXO1 loss. Consistent with a dependency on EXO1-mediated SSA, we find that BRCA1-mutated tumors show elevated EXO1 expression and increased SSA-associated genomic scars compared with BRCA1-proficient tumors. Overall, our findings uncover EXO1 as a promising therapeutic target for BRCA1-deficient tumors.
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Affiliation(s)
- Bert van de Kooij
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands; Department of Medical Oncology, University Medical Center Groningen, Groningen 9713 GZ, the Netherlands
| | - Anne Schreuder
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands; Oncode Institute, Utrecht 3521 AL, the Netherlands
| | - Raphael Pavani
- Laboratory of Genome Integrity, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Veronica Garzero
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands; Oncode Institute, Utrecht 3521 AL, the Netherlands
| | - Sidrit Uruci
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands
| | - Tiemen J Wendel
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands; Oncode Institute, Utrecht 3521 AL, the Netherlands
| | - Arne van Hoeck
- Oncode Institute, Utrecht 3521 AL, the Netherlands; Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht 3584 CG, the Netherlands
| | - Marta San Martin Alonso
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands; Oncode Institute, Utrecht 3521 AL, the Netherlands
| | - Marieke Everts
- Department of Medical Oncology, University Medical Center Groningen, Groningen 9713 GZ, the Netherlands
| | - Dana Koerse
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands
| | - Elsa Callen
- Laboratory of Genome Integrity, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jasper Boom
- Sequencing Analysis Support Core, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands
| | - Hailiang Mei
- Sequencing Analysis Support Core, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands
| | - Edwin Cuppen
- Oncode Institute, Utrecht 3521 AL, the Netherlands; Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht 3584 CG, the Netherlands; Hartwig Medical Foundation, Amsterdam 1098 XH, the Netherlands
| | - Martijn S Luijsterburg
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands
| | - Marcel A T M van Vugt
- Department of Medical Oncology, University Medical Center Groningen, Groningen 9713 GZ, the Netherlands
| | - André Nussenzweig
- Laboratory of Genome Integrity, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Haico van Attikum
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands.
| | - Sylvie M Noordermeer
- Department of Human Genetics, Leiden University Medical Centre, Leiden 2333 ZC, the Netherlands; Oncode Institute, Utrecht 3521 AL, the Netherlands.
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6
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Palihati M, Iwasaki H, Tsubouchi H. Analysis of the indispensable RAD51 cofactor BRCA2 in Naganishia liquefaciens, a Basidiomycota yeast. Life Sci Alliance 2024; 7:e202302342. [PMID: 38016757 PMCID: PMC10684384 DOI: 10.26508/lsa.202302342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 11/16/2023] [Accepted: 11/20/2023] [Indexed: 11/30/2023] Open
Abstract
The BRCA2 tumor suppressor plays a critical role in homologous recombination by regulating RAD51, the eukaryotic homologous recombinase. We identified the BRCA2 homolog in a Basidiomycota yeast, Naganishia liquefaciens BRCA2 homologs are found in many Basidiomycota species but not in Ascomycota species. Naganishia BRCA2 (Brh2, for BRCA2 homolog) is about one-third the size of human BRCA2. Brh2 carries three potential BRC repeats with two oligonucleotide/oligosaccharide-binding domains. The homolog of DSS1, a small acidic protein serving as an essential partner of BRCA2 was also identified. The yeast two-hybrid assay shows the interaction of Brh2 with both Rad51 and Dss1. Unlike human BRCA2, Brh2 is not required for normal cell growth, whereas loss of Dss1 results in slow growth. The loss of Brh2 caused pronounced sensitivity to UV and ionizing radiation, and their HR ability, as assayed by gene-targeting efficiency, is compromised. These phenotypes are indistinguishable from those of the rad51 mutant, and the rad51 brh2 double mutant. Naganishia Brh2 is likely the BRCA2 ortholog that functions as an indispensable auxiliary factor for Rad51.
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Affiliation(s)
- Maierdan Palihati
- https://ror.org/0112mx960 Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Hiroshi Iwasaki
- https://ror.org/0112mx960 Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Hideo Tsubouchi
- https://ror.org/0112mx960 Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
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7
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Bader AS, Bushell M. iMUT-seq: high-resolution DSB-induced mutation profiling reveals prevalent homologous-recombination dependent mutagenesis. Nat Commun 2023; 14:8419. [PMID: 38110444 PMCID: PMC10728174 DOI: 10.1038/s41467-023-44167-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 12/04/2023] [Indexed: 12/20/2023] Open
Abstract
DNA double-strand breaks (DSBs) are the most mutagenic form of DNA damage, and play a significant role in cancer biology, neurodegeneration and aging. However, studying DSB-induced mutagenesis is limited by our current approaches. Here, we describe iMUT-seq, a technique that profiles DSB-induced mutations at high-sensitivity and single-nucleotide resolution around endogenous DSBs. By depleting or inhibiting 20 DSB-repair factors we define their mutational signatures in detail, revealing insights into the mechanisms of DSB-induced mutagenesis. Notably, we find that homologous-recombination (HR) is more mutagenic than previously thought, inducing prevalent base substitutions and mononucleotide deletions at distance from the break due to DNA-polymerase errors. Simultaneously, HR reduces translocations, suggesting a primary role of HR is specifically the prevention of genomic rearrangements. The results presented here offer fundamental insights into DSB-induced mutagenesis and have significant implications for our understanding of cancer biology and the development of DDR-targeting chemotherapeutics.
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Affiliation(s)
- Aldo S Bader
- Cancer Research UK Beatson Institute, Glasgow, G61 1BD, UK.
- Cancer Research UK/CI, University of Cambridge, Li Ka Shing Centre, Cambridge, CB2 0RE, UK.
- The Gurdon Institute, University of Cambridge, Biochemistry, Cambridge, UK.
| | - Martin Bushell
- Cancer Research UK Beatson Institute, Glasgow, G61 1BD, UK.
- Institute of Cancer Sciences, University of Glasgow, Glasgow, G61 1QH, UK.
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8
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Setton J, Hadi K, Choo ZN, Kuchin KS, Tian H, Da Cruz Paula A, Rosiene J, Selenica P, Behr J, Yao X, Deshpande A, Sigouros M, Manohar J, Nauseef JT, Mosquera JM, Elemento O, Weigelt B, Riaz N, Reis-Filho JS, Powell SN, Imieliński M. Long-molecule scars of backup DNA repair in BRCA1- and BRCA2-deficient cancers. Nature 2023; 621:129-137. [PMID: 37587346 PMCID: PMC10482687 DOI: 10.1038/s41586-023-06461-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 07/20/2023] [Indexed: 08/18/2023]
Abstract
Homologous recombination (HR) deficiency is associated with DNA rearrangements and cytogenetic aberrations1. Paradoxically, the types of DNA rearrangements that are specifically associated with HR-deficient cancers only minimally affect chromosomal structure2. Here, to address this apparent contradiction, we combined genome-graph analysis of short-read whole-genome sequencing (WGS) profiles across thousands of tumours with deep linked-read WGS of 46 BRCA1- or BRCA2-mutant breast cancers. These data revealed a distinct class of HR-deficiency-enriched rearrangements called reciprocal pairs. Linked-read WGS showed that reciprocal pairs with identical rearrangement orientations gave rise to one of two distinct chromosomal outcomes, distinguishable only with long-molecule data. Whereas one (cis) outcome corresponded to the copying and pasting of a small segment to a distant site, a second (trans) outcome was a quasi-balanced translocation or multi-megabase inversion with substantial (10 kb) duplications at each junction. We propose an HR-independent replication-restart repair mechanism to explain the full spectrum of reciprocal pair outcomes. Linked-read WGS also identified single-strand annealing as a repair pathway that is specific to BRCA2 deficiency in human cancers. Integrating these features in a classifier improved discrimination between BRCA1- and BRCA2-deficient genomes. In conclusion, our data reveal classes of rearrangements that are specific to BRCA1 or BRCA2 deficiency as a source of cytogenetic aberrations in HR-deficient cells.
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Affiliation(s)
- Jeremy Setton
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Kevin Hadi
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA
- New York Genome Center, New York, NY, USA
- Physiology and Biophysics PhD program, Weill Cornell Medicine, New York, NY, USA
| | - Zi-Ning Choo
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA
- New York Genome Center, New York, NY, USA
- Physiology and Biophysics PhD program, Weill Cornell Medicine, New York, NY, USA
| | - Katherine S Kuchin
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA
- New York Genome Center, New York, NY, USA
- Tri-Institutional PhD Program in Computational Biology and Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Huasong Tian
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA
- New York Genome Center, New York, NY, USA
| | - Arnaud Da Cruz Paula
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Joel Rosiene
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA
- New York Genome Center, New York, NY, USA
| | - Pier Selenica
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Julie Behr
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA
- New York Genome Center, New York, NY, USA
- Tri-Institutional PhD Program in Computational Biology and Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Xiaotong Yao
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA
- New York Genome Center, New York, NY, USA
- Tri-Institutional PhD Program in Computational Biology and Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Aditya Deshpande
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA
- New York Genome Center, New York, NY, USA
- Tri-Institutional PhD Program in Computational Biology and Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Michael Sigouros
- Englander Institute for Precision Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Jyothi Manohar
- Englander Institute for Precision Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Jones T Nauseef
- New York Genome Center, New York, NY, USA
- Englander Institute for Precision Medicine, Weill Cornell Medicine, New York, NY, USA
- Division of Hematology and Medical Oncology, Department of Medicine, Weill Cornell Medicine, New York, NY, USA
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA
| | - Juan-Miguel Mosquera
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA
- Englander Institute for Precision Medicine, Weill Cornell Medicine, New York, NY, USA
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA
| | - Olivier Elemento
- Englander Institute for Precision Medicine, Weill Cornell Medicine, New York, NY, USA
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
| | - Britta Weigelt
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Nadeem Riaz
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jorge S Reis-Filho
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Simon N Powell
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
| | - Marcin Imieliński
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA.
- New York Genome Center, New York, NY, USA.
- Englander Institute for Precision Medicine, Weill Cornell Medicine, New York, NY, USA.
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA.
- Institute for Computational Biomedicine, Weill Cornell Medicine, New York, NY, USA.
- Department of Pathology and Perlmutter Cancer Center, NYU Grossman School of Medicine, New York, NY, USA.
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9
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Dilmac S, Ozpolat B. Mechanisms of PARP-Inhibitor-Resistance in BRCA-Mutated Breast Cancer and New Therapeutic Approaches. Cancers (Basel) 2023; 15:3642. [PMID: 37509303 PMCID: PMC10378018 DOI: 10.3390/cancers15143642] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 07/10/2023] [Accepted: 07/11/2023] [Indexed: 07/30/2023] Open
Abstract
The recent success of Poly (ADP-ribose) polymerase (PARP) inhibitors has led to the approval of four different PARP inhibitors for the treatment of BRCA1/2-mutant breast and ovarian cancers. About 40-50% of BRCA1/2-mutated patients do not respond to PARP inhibitors due to a preexisting innate or intrinsic resistance; the majority of patients who initially respond to the therapy inevitably develop acquired resistance. However, subsets of patients experience a long-term response (>2 years) to treatment with PARP inhibitors. Poly (ADP-ribose) polymerase 1 (PARP1) is an enzyme that plays an important role in the recognition and repair of DNA damage. PARP inhibitors induce "synthetic lethality" in patients with tumors with a homologous-recombination-deficiency (HRD). Several molecular mechanisms have been identified as causing PARP-inhibitor-resistance. In this review, we focus on the molecular mechanisms underlying the PARP-inhibitor-resistance in BRCA-mutated breast cancer and summarize potential therapeutic strategies to overcome the resistance mechanisms.
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Affiliation(s)
- Sayra Dilmac
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Bulent Ozpolat
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030, USA
- Houston Methodist Neal Cancer Center, Houston, TX 77030, USA
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10
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Martino J, Siri SO, Calzetta NL, Paviolo NS, Garro C, Pansa MF, Carbajosa S, Brown AC, Bocco JL, Gloger I, Drewes G, Madauss KP, Soria G, Gottifredi V. Inhibitors of Rho kinases (ROCK) induce multiple mitotic defects and synthetic lethality in BRCA2-deficient cells. eLife 2023; 12:e80254. [PMID: 37073955 PMCID: PMC10185344 DOI: 10.7554/elife.80254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 04/18/2023] [Indexed: 04/20/2023] Open
Abstract
The trapping of Poly-ADP-ribose polymerase (PARP) on DNA caused by PARP inhibitors (PARPi) triggers acute DNA replication stress and synthetic lethality (SL) in BRCA2-deficient cells. Hence, DNA damage is accepted as a prerequisite for SL in BRCA2-deficient cells. In contrast, here we show that inhibiting ROCK in BRCA2-deficient cells triggers SL independently from acute replication stress. Such SL is preceded by polyploidy and binucleation resulting from cytokinesis failure. Such initial mitosis abnormalities are followed by other M phase defects, including anaphase bridges and abnormal mitotic figures associated with multipolar spindles, supernumerary centrosomes and multinucleation. SL was also triggered by inhibiting Citron Rho-interacting kinase, another enzyme that, similarly to ROCK, regulates cytokinesis. Together, these observations demonstrate that cytokinesis failure triggers mitotic abnormalities and SL in BRCA2-deficient cells. Furthermore, the prevention of mitotic entry by depletion of Early mitotic inhibitor 1 (EMI1) augmented the survival of BRCA2-deficient cells treated with ROCK inhibitors, thus reinforcing the association between M phase and cell death in BRCA2-deficient cells. This novel SL differs from the one triggered by PARPi and uncovers mitosis as an Achilles heel of BRCA2-deficient cells.
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Affiliation(s)
| | | | | | | | - Cintia Garro
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, CIBICI-CONICET, Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de CórdobaCórdobaArgentina
- OncoPrecisionCórdobaArgentina
| | - Maria F Pansa
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, CIBICI-CONICET, Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de CórdobaCórdobaArgentina
| | - Sofía Carbajosa
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, CIBICI-CONICET, Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de CórdobaCórdobaArgentina
- OncoPrecisionCórdobaArgentina
| | - Aaron C Brown
- Center for Molecular Medicine, Maine Medical Center Research InstituteScarboroughUnited States
| | - José Luis Bocco
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, CIBICI-CONICET, Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de CórdobaCórdobaArgentina
| | - Israel Gloger
- GlaxoSmithKline-Trust in Science, Global Health R&DStevenageUnited Kingdom
| | - Gerard Drewes
- GlaxoSmithKline-Trust in Science, Global Health R&DStevenageUnited Kingdom
| | - Kevin P Madauss
- GlaxoSmithKline-Trust in Science, Global Health R&DUpper ProvidenceUnited States
| | - Gastón Soria
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, CIBICI-CONICET, Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de CórdobaCórdobaArgentina
- OncoPrecisionCórdobaArgentina
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11
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Bell JC, Dombrowski CC, Plank JL, Jensen RB, Kowalczykowski SC. BRCA2 chaperones RAD51 to single molecules of RPA-coated ssDNA. Proc Natl Acad Sci U S A 2023; 120:e2221971120. [PMID: 36976771 PMCID: PMC10083600 DOI: 10.1073/pnas.2221971120] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 02/24/2023] [Indexed: 03/29/2023] Open
Abstract
Mutations in the breast cancer susceptibility gene, BRCA2, greatly increase an individual's lifetime risk of developing breast and ovarian cancers. BRCA2 suppresses tumor formation by potentiating DNA repair via homologous recombination. Central to recombination is the assembly of a RAD51 nucleoprotein filament, which forms on single-stranded DNA (ssDNA) generated at or near the site of chromosomal damage. However, replication protein-A (RPA) rapidly binds to and continuously sequesters this ssDNA, imposing a kinetic barrier to RAD51 filament assembly that suppresses unregulated recombination. Recombination mediator proteins-of which BRCA2 is the defining member in humans-alleviate this kinetic barrier to catalyze RAD51 filament formation. We combined microfluidics, microscopy, and micromanipulation to directly measure both the binding of full-length BRCA2 to-and the assembly of RAD51 filaments on-a region of RPA-coated ssDNA within individual DNA molecules designed to mimic a resected DNA lesion common in replication-coupled recombinational repair. We demonstrate that a dimer of RAD51 is minimally required for spontaneous nucleation; however, growth self-terminates below the diffraction limit. BRCA2 accelerates nucleation of RAD51 to a rate that approaches the rapid association of RAD51 to naked ssDNA, thereby overcoming the kinetic block imposed by RPA. Furthermore, BRCA2 eliminates the need for the rate-limiting nucleation of RAD51 by chaperoning a short preassembled RAD51 filament onto the ssDNA complexed with RPA. Therefore, BRCA2 regulates recombination by initiating RAD51 filament formation.
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Affiliation(s)
- Jason C. Bell
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA95616
- Department of Molecular and Cellular Biology, University of California, Davis, CA95616
| | - Christopher C. Dombrowski
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA95616
- Department of Molecular and Cellular Biology, University of California, Davis, CA95616
| | - Jody L. Plank
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA95616
- Department of Molecular and Cellular Biology, University of California, Davis, CA95616
| | - Ryan B. Jensen
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA95616
- Department of Molecular and Cellular Biology, University of California, Davis, CA95616
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT06520
| | - Stephen C. Kowalczykowski
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA95616
- Department of Molecular and Cellular Biology, University of California, Davis, CA95616
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12
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Gianni P, Matenoglou E, Geropoulos G, Agrawal N, Adnani H, Zafeiropoulos S, Miyara SJ, Guevara S, Mumford JM, Molmenti EP, Giannis D. The Fanconi anemia pathway and Breast Cancer: A comprehensive review of clinical data. Clin Breast Cancer 2021; 22:10-25. [PMID: 34489172 DOI: 10.1016/j.clbc.2021.08.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 07/17/2021] [Accepted: 08/05/2021] [Indexed: 02/08/2023]
Abstract
The development of breast cancer depends on several risk factors, including environmental, lifestyle and genetic factors. Despite the evolution of DNA sequencing techniques and biomarker detection, the epidemiology and mechanisms of various breast cancer susceptibility genes have not been elucidated yet. Dysregulation of the DNA damage response causes genomic instability and increases the rate of mutagenesis and the risk of carcinogenesis. The Fanconi Anemia (FA) pathway is an important component of the DNA damage response and plays a critical role in the repair of DNA interstrand crosslinks and genomic stability. The FA pathway involves 22 recognized genes and specific mutations have been identified as the underlying defect in the majority of FA patients. A thorough understanding of the function and epidemiology of these genes in breast cancer is critical for the development and implementation of individualized therapies that target unique tumor profiles. Targeted therapies (PARP inhibitors) exploiting the FA pathway gene defects have been developed and have shown promising results. This narrative review summarizes the current literature on the involvement of FA genes in sporadic and familial breast cancer with a focus on clinical data derived from large cohorts.
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Affiliation(s)
- Panagiota Gianni
- Department of Internal Medicine III, Hematology, Oncology, Palliative Medicine, Rheumatology and Infectious Diseases, University Hospital Ulm, Germany
| | - Evangelia Matenoglou
- Medical School, Aristotle University of Thessaloniki, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Georgios Geropoulos
- Thoracic Surgery Department, University College London Hospitals NHS Foundation Trust, London
| | - Nirav Agrawal
- Feinstein Institutes for Medical Research at Northwell Health, Manhasset, New York, NY
| | - Harsha Adnani
- Feinstein Institutes for Medical Research at Northwell Health, Manhasset, New York, NY
| | - Stefanos Zafeiropoulos
- Feinstein Institutes for Medical Research at Northwell Health, Manhasset, New York, NY; Elmezzi Graduate School of Molecular Medicine, Northwell Health, Manhasset, New York, NY
| | - Santiago J Miyara
- Feinstein Institutes for Medical Research at Northwell Health, Manhasset, New York, NY; Elmezzi Graduate School of Molecular Medicine, Northwell Health, Manhasset, New York, NY
| | - Sara Guevara
- Department of Surgery, North Shore University Hospital, Manhasset, New York, NY
| | - James M Mumford
- Department of Family Medicine, Glen Cove Hospital, Glen Cove, New York, NY; Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, NY
| | - Ernesto P Molmenti
- Feinstein Institutes for Medical Research at Northwell Health, Manhasset, New York, NY; Department of Surgery, North Shore University Hospital, Manhasset, New York, NY; Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, NY
| | - Dimitrios Giannis
- Feinstein Institutes for Medical Research at Northwell Health, Manhasset, New York, NY.
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13
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Fu R, Wang C, Shen H, Zhang J, Higgins JD, Liang W. Rice OsBRCA2 Is Required for DNA Double-Strand Break Repair in Meiotic Cells. FRONTIERS IN PLANT SCIENCE 2020; 11:600820. [PMID: 33304374 PMCID: PMC7701097 DOI: 10.3389/fpls.2020.600820] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 10/27/2020] [Indexed: 06/06/2023]
Abstract
The mammalian BREAST CANCER 2 (BRCA2) gene is a tumor suppressor that plays a crucial role in DNA repair and homologous recombination (HR). Here, we report the identification and characterization of OsBRCA2, the rice orthologue of human BRCA2. Osbrca2 mutant plants exhibit normal vegetative growth but experience complete male and female sterility as a consequence of severe meiotic defects. Pairing, synapsis and recombination are impaired in osbrca2 male meiocytes, leading to chromosome entanglements and fragmentation. In the absence of OsBRCA2, localization to the meiotic chromosome axes of the strand-invasion proteins OsRAD51 and OsDMC1 is severely reduced and in vitro OsBRCA2 directly interacts with OsRAD51 and OsDMC1. These results indicate that OsBRCA2 is essential for facilitating the loading of OsRAD51 and OsDMC1 onto resected ends of programmed double-strand breaks (DSB) during meiosis to promote single-end invasions of homologous chromosomes and accurate recombination. In addition, treatment of osbrca2-1 seedlings with mitomycin C (MMC) led to hypersensitivity. As MMC is a genotoxic agent that creates DNA lesions in the somatic cells that can only be repaired by HR, these results suggest that OsBRCA2 has a conserved role in DSB repair and HR in rice.
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Affiliation(s)
- Ruifeng Fu
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University–University of Adelaide Joint Centre for Agriculture and Health, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Chong Wang
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University–University of Adelaide Joint Centre for Agriculture and Health, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Hongyu Shen
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University–University of Adelaide Joint Centre for Agriculture and Health, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Jie Zhang
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University–University of Adelaide Joint Centre for Agriculture and Health, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - James D. Higgins
- Department of Genetics and Genome Biology, University of Leicester,Leicester, United Kingdom
| | - Wanqi Liang
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University–University of Adelaide Joint Centre for Agriculture and Health, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
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14
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Irie H, Yamamoto I, Tarumoto Y, Tashiro S, Runge KW, Ishikawa F. Telomere-binding proteins Taz1 and Rap1 regulate DSB repair and suppress gross chromosomal rearrangements in fission yeast. PLoS Genet 2019; 15:e1008335. [PMID: 31454352 PMCID: PMC6733473 DOI: 10.1371/journal.pgen.1008335] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 09/09/2019] [Accepted: 07/28/2019] [Indexed: 11/19/2022] Open
Abstract
Genomic rearrangements (gross chromosomal rearrangements, GCRs) threatens genome integrity and cause cell death or tumor formation. At the terminus of linear chromosomes, a telomere-binding protein complex, called shelterin, ensures chromosome stability by preventing chromosome end-to-end fusions and regulating telomere length homeostasis. As such, shelterin-mediated telomere functions play a pivotal role in suppressing GCR formation. However, it remains unclear whether the shelterin proteins play any direct role in inhibiting GCR at non-telomeric regions. Here, we have established a GCR assay for the first time in fission yeast and measured GCR rates in various mutants. We found that fission yeast cells lacking shelterin components Taz1 or Rap1 (mammalian TRF1/2 or RAP1 homologues, respectively) showed higher GCR rates compared to wild-type, accumulating large chromosome deletions. Genetic dissection of Rap1 revealed that Rap1 contributes to inhibiting GCRs via two independent pathways. The N-terminal BRCT-domain promotes faithful DSB repair, as determined by I-SceI-mediated DSB-induction experiments; moreover, association with Poz1 mediated by the central Poz1-binding domain regulates telomerase accessibility to DSBs, leading to suppression of de novo telomere additions. Our data highlight unappreciated functions of the shelterin components Taz1 and Rap1 in maintaining genome stability, specifically by preventing non-telomeric GCRs.
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Affiliation(s)
- Hiroyuki Irie
- Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Io Yamamoto
- Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Yusuke Tarumoto
- Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Sanki Tashiro
- Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Kurt W. Runge
- Department of Molecular Genetics, Cleveland Clinic Lerner College of Medicine, Cleveland, Ohio, United States of America
| | - Fuyuki Ishikawa
- Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, Japan
- * E-mail:
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15
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Jonsson P, Bandlamudi C, Cheng ML, Srinivasan P, Chavan SS, Friedman ND, Rosen EY, Richards AL, Bouvier N, Selcuklu SD, Bielski CM, Abida W, Mandelker D, Birsoy O, Zhang L, Zehir A, Donoghue MTA, Baselga J, Offit K, Scher HI, O'Reilly EM, Stadler ZK, Schultz N, Socci ND, Viale A, Ladanyi M, Robson ME, Hyman DM, Berger MF, Solit DB, Taylor BS. Tumour lineage shapes BRCA-mediated phenotypes. Nature 2019; 571:576-579. [PMID: 31292550 PMCID: PMC7048239 DOI: 10.1038/s41586-019-1382-1] [Citation(s) in RCA: 270] [Impact Index Per Article: 54.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 06/12/2019] [Indexed: 02/06/2023]
Abstract
Mutations in BRCA1 and BRCA2 predispose individuals to certain cancers1-3, and disease-specific screening and preventative strategies have reduced cancer mortality in affected patients4,5. These classical tumour-suppressor genes have tumorigenic effects associated with somatic biallelic inactivation, although haploinsufficiency may also promote the formation and progression of tumours6,7. Moreover, BRCA1/2-mutant tumours are often deficient in the repair of double-stranded DNA breaks by homologous recombination8-13, and consequently exhibit increased therapeutic sensitivity to platinum-containing therapy and inhibitors of poly-(ADP-ribose)-polymerase (PARP)14,15. However, the phenotypic and therapeutic relevance of mutations in BRCA1 or BRCA2 remains poorly defined in most cancer types. Here we show that in the 2.7% and 1.8% of patients with advanced-stage cancer and germline pathogenic or somatic loss-of-function alterations in BRCA1/2, respectively, selective pressure for biallelic inactivation, zygosity-dependent phenotype penetrance, and sensitivity to PARP inhibition were observed only in tumour types associated with increased heritable cancer risk in BRCA1/2 carriers (BRCA-associated cancer types). Conversely, among patients with non-BRCA-associated cancer types, most carriers of these BRCA1/2 mutation types had evidence for tumour pathogenesis that was independent of mutant BRCA1/2. Overall, mutant BRCA is an indispensable founding event for some tumours, but in a considerable proportion of other cancers, it appears to be biologically neutral-a difference predominantly conditioned by tumour lineage-with implications for disease pathogenesis, screening, design of clinical trials and therapeutic decision-making.
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Affiliation(s)
- Philip Jonsson
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Chaitanya Bandlamudi
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Michael L Cheng
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Dana-Farber Cancer Institute, Boston, MA, USA
| | - Preethi Srinivasan
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Shweta S Chavan
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Noah D Friedman
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Ezra Y Rosen
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Allison L Richards
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Nancy Bouvier
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - S Duygu Selcuklu
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Craig M Bielski
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Wassim Abida
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Diana Mandelker
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Ozge Birsoy
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Liying Zhang
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Ahmet Zehir
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Mark T A Donoghue
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - José Baselga
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- AstraZeneca, Waltham, MA, USA
| | - Kenneth Offit
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Howard I Scher
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Eileen M O'Reilly
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Zsofia K Stadler
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Nikolaus Schultz
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Nicholas D Socci
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Agnes Viale
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Marc Ladanyi
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Mark E Robson
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - David M Hyman
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Weill Cornell Medical College, New York, NY, USA
| | - Michael F Berger
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Weill Cornell Medical College, New York, NY, USA.
| | - David B Solit
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Weill Cornell Medical College, New York, NY, USA.
| | - Barry S Taylor
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Weill Cornell Medical College, New York, NY, USA.
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16
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Farolfi A, Gurioli G, Fugazzola P, Burgio SL, Casanova C, Ravaglia G, Altavilla A, Costantini M, Amadori A, Framarini M, Ansaloni L, De Giorgi U. Immune System and DNA Repair Defects in Ovarian Cancer: Implications for Locoregional Approaches. Int J Mol Sci 2019; 20:E2569. [PMID: 31130614 PMCID: PMC6566239 DOI: 10.3390/ijms20102569] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 05/07/2019] [Accepted: 05/23/2019] [Indexed: 01/26/2023] Open
Abstract
In the last few years, substantial progress has been made in the treatment of ovarian cancer, with increased knowledge about the biology of the disease. Ovarian cancer is a neoplasm strongly linked to defects in DNA repair mechanisms, where deficiency in the homologous recombination (HR) system results in a better response of ovarian cancers to therapy, whether platinum-based chemotherapy, anthracyclines, or poly (ADP-ribose) polymerase (PARP) inhibitors. More recently, it has been demonstrated that different ovarian cancer histotypes may have different immunogenicity. Interestingly, defects in HR systems are associated more frequently with higher tumor infiltrating lymphocytes, providing a rationale for developing combination therapy with immune-modulating agents and PARP inhibitors. Again, locoregional therapies combining heat shock and chemotherapy delivery have been shown to induce an anticancer immune response in vitro. Thus, the potential for locoregional therapeutic approaches that may impact the immune system, perhaps in combination with immune-modulating agents or PARP inhibitors, needs to be further explored. With this premise, we reviewed the main biological and clinical data demonstrating a strict interplay between the immune system, DNA repair mechanisms, and intraperitoneal therapies in ovarian cancer, with a focus on potential future therapeutic implications.
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Affiliation(s)
- Alberto Farolfi
- Department of Medical Oncology, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola 47014, Italy.
| | - Giorgia Gurioli
- Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola 47014, Italy.
| | - Paola Fugazzola
- General and Emergency Surgery, Maurizio Bufalini Hospital, Cesena 47521, Italy.
| | - Salvatore Luca Burgio
- Department of Medical Oncology, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola 47014, Italy.
| | - Claudia Casanova
- Oncology Department, Santa Maria delle Croci Hospital, Ravenna 48121, Italy.
| | - Giorgia Ravaglia
- Unit of Biostatistics and Clinical Trials, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola 47014, Italy.
| | - Amelia Altavilla
- Department of Medical Oncology, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola 47014, Italy.
| | | | - Andrea Amadori
- Department of Gynecological, Morgagni-Pierantoni Hospital, Forlì 47121, Italy.
| | - Massimo Framarini
- Department of General Surgery, Morgagni-Pierantoni Hospital, Forlì 47121, Italy.
| | - Luca Ansaloni
- General and Emergency Surgery, Maurizio Bufalini Hospital, Cesena 47521, Italy.
| | - Ugo De Giorgi
- Department of Medical Oncology, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola 47014, Italy.
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17
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Luo Y, Wu J, Zou J, Cao Y, He Y, Ling H, Zeng T. BCL10 in cell survival after DNA damage. Clin Chim Acta 2019; 495:301-308. [PMID: 31047877 DOI: 10.1016/j.cca.2019.04.077] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 04/21/2019] [Accepted: 04/23/2019] [Indexed: 01/01/2023]
Abstract
The complex defense mechanism of the DNA damage response (DDR) developed by cells during long-term evolution is an important mechanism for maintaining the stability of the genome. Defects in the DDR pathway can lead to the occurrence of various diseases, including tumor development. Most cancer treatments cause DNA damage and apoptosis. However, cancer cells have the natural ability to repair this damage and inhibit apoptosis, ultimately leading to the development of drug resistance. Therefore, investigating the mechanism of DNA damage may contribute markedly to the future treatment of cancer. The CARMA-BCL10-MALT1 (CBM) complex formed by B cell lymphoma/leukemia 10 (BCL10) regulates apoptosis by activating NF-κB signaling. BCL10 is involved in the formation of complexes that antagonize apoptosis and contribute to cell survival after DNA damage, with cytoplasmic BCL10 entering the nucleus to promote DNA damage repair, including histone ubiquitination and the recruitment of homologous recombination (HR) repair factors. This article reviews the role of BCL10 in cell survival following DNA damage.
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Affiliation(s)
- Yichen Luo
- Key Laboratory of Tumor Cellular & Molecular Pathology, College of Hunan Province, Cancer Research Institute, University of South China,Hengyang, Hunan 421001, China; Hunan Provincial Education Department document (Approval number: 2014-405], Hunan Province Cooperative innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan 421001, China
| | - Jing Wu
- Key Laboratory of Tumor Cellular & Molecular Pathology, College of Hunan Province, Cancer Research Institute, University of South China,Hengyang, Hunan 421001, China; Hunan Provincial Education Department document (Approval number: 2014-405], Hunan Province Cooperative innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan 421001, China
| | - Juan Zou
- Key Laboratory of Tumor Cellular & Molecular Pathology, College of Hunan Province, Cancer Research Institute, University of South China,Hengyang, Hunan 421001, China; Hunan Provincial Education Department document (Approval number: 2014-405], Hunan Province Cooperative innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan 421001, China
| | - Yijing Cao
- Key Laboratory of Tumor Cellular & Molecular Pathology, College of Hunan Province, Cancer Research Institute, University of South China,Hengyang, Hunan 421001, China; Hunan Provincial Education Department document (Approval number: 2014-405], Hunan Province Cooperative innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan 421001, China
| | - Yan He
- Key Laboratory of Tumor Cellular & Molecular Pathology, College of Hunan Province, Cancer Research Institute, University of South China,Hengyang, Hunan 421001, China; Department of Pathology, Longgang Central Hospital, Shenzhen, Guangdong 518000, China
| | - Hui Ling
- Key Laboratory of Tumor Cellular & Molecular Pathology, College of Hunan Province, Cancer Research Institute, University of South China,Hengyang, Hunan 421001, China; Hunan Provincial Education Department document (Approval number: 2014-405], Hunan Province Cooperative innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan 421001, China.
| | - Tiebing Zeng
- Hunan Provincial Education Department document (Approval number: 2014-405], Hunan Province Cooperative innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan 421001, China; Institute of Pathogenic Biology and Key Laboratory of Special Pathogen Prevention and Control of Hunan Province, University of South China, Hengyang, Hunan 421001, China.
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18
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Macedo GS, Alemar B, Ashton-Prolla P. Reviewing the characteristics of BRCA and PALB2-related cancers in the precision medicine era. Genet Mol Biol 2019; 42:215-231. [PMID: 31067289 PMCID: PMC6687356 DOI: 10.1590/1678-4685-gmb-2018-0104] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 10/24/2018] [Indexed: 12/24/2022] Open
Abstract
Germline mutations in BRCA1 and BRCA2 (BRCA) genes confer high risk of developing cancer, especially breast and ovarian tumors. Since the cloning of these tumor suppressor genes over two decades ago, a significant amount of research has been done. Most recently, monoallelic loss-of-function mutations in PALB2 have also been shown to increase the risk of breast cancer. The identification of BRCA1, BRCA2 and PALB2 as proteins involved in DNA double-strand break repair by homologous recombination and of the impact of complete loss of BRCA1 or BRCA2 within tumors have allowed the development of novel therapeutic approaches for patients with germline or somatic mutations in said genes. Despite the advances, especially in the clinical use of PARP inhibitors, key gaps remain. Now, new roles for BRCA1 and BRCA2 are emerging and old concepts, such as the classical two-hit hypothesis for tumor suppression, have been questioned, at least for some BRCA functions. Here aspects regarding cancer predisposition, cellular functions, histological and genomic findings in BRCA and PALB2-related tumors will be presented, in addition to an up-to-date review of the evolution and challenges in the development and clinical use of PARP inhibitors.
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Affiliation(s)
- Gabriel S Macedo
- Post-Graduate Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.,Precision Medicine Program, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil
| | - Barbara Alemar
- Post-Graduate Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Patricia Ashton-Prolla
- Post-Graduate Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.,Precision Medicine Program, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil
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19
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Zhou Q, Holloman WK, Kojic M. Approaches to Understanding the Mediator Function of Brh2 in Ustilago maydis. Methods Enzymol 2018; 600:513-525. [PMID: 29458772 DOI: 10.1016/bs.mie.2017.11.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Primary components of the homologous recombination pathway in eukaryotes include Rad51 whose function is to search for DNA sequence homology and promote strand exchange, its mediator BRCA2, and Dss1, a key regulator of BRCA2. We seek to understand the role of BRCA2 in governing the activity of Rad51 and to learn how BRCA2 function is regulated by Dss1. We use the microbe Ustilago maydis as a model system for experimentation because it has a well-conserved BRCA2-homolog, Brh2, and is amenable to biochemical and molecular genetic manipulations and analysis. The powerful attributes of this system open the way for gaining insight into BRCA2's molecular mechanism through avenues not immediately approachable in the vertebrate systems. Here we provide protocols for preparing Brh2, Dss1, and Rad51 as reagents for use in biochemical assays to monitor function and present methods for transposon-based mutational analysis of Brh2 for use in genetic dissection of function.
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Affiliation(s)
- Qingwen Zhou
- Weill Cornell Medical College, New York, NY, United States
| | | | - Milorad Kojic
- Weill Cornell Medical College, New York, NY, United States
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20
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Zafar F, Okita AK, Onaka AT, Su J, Katahira Y, Nakayama JI, Takahashi TS, Masukata H, Nakagawa T. Regulation of mitotic recombination between DNA repeats in centromeres. Nucleic Acids Res 2017; 45:11222-11235. [PMID: 28977643 PMCID: PMC5737691 DOI: 10.1093/nar/gkx763] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 08/17/2017] [Indexed: 12/18/2022] Open
Abstract
Centromeres that are essential for faithful segregation of chromosomes consist of unique DNA repeats in many eukaryotes. Although recombination is under-represented around centromeres during meiosis, little is known about recombination between centromere repeats in mitotic cells. Here, we compared spontaneous recombination that occurs between ade6B/ade6X inverted repeats integrated at centromere 1 (cen1) or at a non-centromeric ura4 locus in fission yeast. Remarkably, distinct mechanisms of homologous recombination (HR) were observed in centromere and non-centromere regions. Rad51-dependent HR that requires Rad51, Rad54 and Rad52 was predominant in the centromere, whereas Rad51-independent HR that requires Rad52 also occurred in the arm region. Crossovers between inverted repeats (i.e. inversions) were under-represented in the centromere as compared to the arm region. While heterochromatin was dispensable, Mhf1/CENP–S, Mhf2/CENP–X histone-fold proteins and Fml1/FANCM helicase were required to suppress crossovers. Furthermore, Mhf1 and Fml1 were found to prevent gross chromosomal rearrangements mediated by centromere repeats. These data uncovered the regulation of mitotic recombination between DNA repeats in centromeres and its physiological role in maintaining genome integrity.
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Affiliation(s)
- Faria Zafar
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Akiko K Okita
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Atsushi T Onaka
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Jie Su
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Yasuhiro Katahira
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Jun-Ichi Nakayama
- Division of Chromatin Regulation, National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi 44-8585, Japan
| | - Tatsuro S Takahashi
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Hisao Masukata
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Takuro Nakagawa
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
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21
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Pathways and Mechanisms that Prevent Genome Instability in Saccharomyces cerevisiae. Genetics 2017; 206:1187-1225. [PMID: 28684602 PMCID: PMC5500125 DOI: 10.1534/genetics.112.145805] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 04/26/2017] [Indexed: 12/13/2022] Open
Abstract
Genome rearrangements result in mutations that underlie many human diseases, and ongoing genome instability likely contributes to the development of many cancers. The tools for studying genome instability in mammalian cells are limited, whereas model organisms such as Saccharomyces cerevisiae are more amenable to these studies. Here, we discuss the many genetic assays developed to measure the rate of occurrence of Gross Chromosomal Rearrangements (called GCRs) in S. cerevisiae. These genetic assays have been used to identify many types of GCRs, including translocations, interstitial deletions, and broken chromosomes healed by de novo telomere addition, and have identified genes that act in the suppression and formation of GCRs. Insights from these studies have contributed to the understanding of pathways and mechanisms that suppress genome instability and how these pathways cooperate with each other. Integrated models for the formation and suppression of GCRs are discussed.
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22
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Vélez-Cruz R, Johnson DG. The Retinoblastoma (RB) Tumor Suppressor: Pushing Back against Genome Instability on Multiple Fronts. Int J Mol Sci 2017; 18:ijms18081776. [PMID: 28812991 PMCID: PMC5578165 DOI: 10.3390/ijms18081776] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 08/13/2017] [Accepted: 08/13/2017] [Indexed: 12/13/2022] Open
Abstract
The retinoblastoma (RB) tumor suppressor is known as a master regulator of the cell cycle. RB is mutated or functionally inactivated in the majority of human cancers. This transcriptional regulator exerts its function in cell cycle control through its interaction with the E2F family of transcription factors and with chromatin remodelers and modifiers that contribute to the repression of genes important for cell cycle progression. Over the years, studies have shown that RB participates in multiple processes in addition to cell cycle control. Indeed, RB is known to interact with over 200 different proteins and likely exists in multiple complexes. RB, in some cases, acts through its interaction with E2F1, other members of the pocket protein family (p107 and p130), and/or chromatin remodelers and modifiers. RB is a tumor suppressor with important chromatin regulatory functions that affect genomic stability. These functions include the role of RB in DNA repair, telomere maintenance, chromosome condensation and cohesion, and silencing of repetitive regions. In this review we will discuss recent advances in RB biology related to RB, partner proteins, and their non-transcriptional functions fighting back against genomic instability.
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Affiliation(s)
- Renier Vélez-Cruz
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, 1808 Park Road 1C, P.O. Box 389, Smithville, TX 78957, USA.
- Department of Biochemistry, Midwestern University, Chicago College of Osteopathic Medicine, 555 31st Street, Downers Grove, IL 60515, USA.
| | - David G Johnson
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, 1808 Park Road 1C, P.O. Box 389, Smithville, TX 78957, USA.
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23
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Vélez-Cruz R, Manickavinayaham S, Biswas AK, Clary RW, Premkumar T, Cole F, Johnson DG. RB localizes to DNA double-strand breaks and promotes DNA end resection and homologous recombination through the recruitment of BRG1. Genes Dev 2017; 30:2500-2512. [PMID: 27940962 PMCID: PMC5159665 DOI: 10.1101/gad.288282.116] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 11/03/2016] [Indexed: 11/24/2022]
Abstract
The retinoblastoma (RB) tumor suppressor is recognized as a master regulator that controls entry into the S phase of the cell cycle. Its loss leads to uncontrolled cell proliferation and is a hallmark of cancer. RB works by binding to members of the E2F family of transcription factors and recruiting chromatin modifiers to the promoters of E2F target genes. Here we show that RB also localizes to DNA double-strand breaks (DSBs) dependent on E2F1 and ATM kinase activity and promotes DSB repair through homologous recombination (HR), and its loss results in genome instability. RB is necessary for the recruitment of the BRG1 ATPase to DSBs, which stimulates DNA end resection and HR. A knock-in mutation of the ATM phosphorylation site on E2F1 (S29A) prevents the interaction between E2F1 and TopBP1 and recruitment of RB, E2F1, and BRG1 to DSBs. This knock-in mutation also impairs DNA repair, increases genomic instability, and renders mice hypersensitive to IR. Importantly, depletion of RB in osteosarcoma and breast cancer cell lines results in sensitivity to DNA-damaging drugs, which is further exacerbated by poly-ADP ribose polymerase (PARP) inhibitors. We uncovered a novel, nontranscriptional function for RB in HR, which could contribute to genome instability associated with RB loss.
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Affiliation(s)
- Renier Vélez-Cruz
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville Texas 78957, USA
| | - Swarnalatha Manickavinayaham
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville Texas 78957, USA
| | - Anup K Biswas
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville Texas 78957, USA
| | - Regina Weaks Clary
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville Texas 78957, USA.,The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77225, USA
| | - Tolkappiyan Premkumar
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville Texas 78957, USA.,The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77225, USA
| | - Francesca Cole
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville Texas 78957, USA.,The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77225, USA
| | - David G Johnson
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville Texas 78957, USA.,The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77225, USA
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24
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A Class of Environmental and Endogenous Toxins Induces BRCA2 Haploinsufficiency and Genome Instability. Cell 2017; 169:1105-1118.e15. [PMID: 28575672 PMCID: PMC5457488 DOI: 10.1016/j.cell.2017.05.010] [Citation(s) in RCA: 129] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 04/07/2017] [Accepted: 05/02/2017] [Indexed: 02/02/2023]
Abstract
Mutations truncating a single copy of the tumor suppressor, BRCA2, cause cancer susceptibility. In cells bearing such heterozygous mutations, we find that a cellular metabolite and ubiquitous environmental toxin, formaldehyde, stalls and destabilizes DNA replication forks, engendering structural chromosomal aberrations. Formaldehyde selectively depletes BRCA2 via proteasomal degradation, a mechanism of toxicity that affects very few additional cellular proteins. Heterozygous BRCA2 truncations, by lowering pre-existing BRCA2 expression, sensitize to BRCA2 haploinsufficiency induced by transient exposure to natural concentrations of formaldehyde. Acetaldehyde, an alcohol catabolite detoxified by ALDH2, precipitates similar effects. Ribonuclease H1 ameliorates replication fork instability and chromosomal aberrations provoked by aldehyde-induced BRCA2 haploinsufficiency, suggesting that BRCA2 inactivation triggers spontaneous mutagenesis during DNA replication via aberrant RNA-DNA hybrids (R-loops). These findings suggest a model wherein carcinogenesis in BRCA2 mutation carriers can be incited by compounds found pervasively in the environment and generated endogenously in certain tissues with implications for public health.
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25
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Moschetti T, Sharpe T, Fischer G, Marsh ME, Ng HK, Morgan M, Scott DE, Blundell TL, R. Venkitaraman A, Skidmore J, Abell C, Hyvönen M. Engineering Archeal Surrogate Systems for the Development of Protein-Protein Interaction Inhibitors against Human RAD51. J Mol Biol 2016; 428:4589-4607. [PMID: 27725183 PMCID: PMC5117717 DOI: 10.1016/j.jmb.2016.10.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Revised: 10/02/2016] [Accepted: 10/04/2016] [Indexed: 02/02/2023]
Abstract
Protein-protein interactions (PPIs) are increasingly important targets for drug discovery. Efficient fragment-based drug discovery approaches to tackle PPIs are often stymied by difficulties in the production of stable, unliganded target proteins. Here, we report an approach that exploits protein engineering to "humanise" thermophilic archeal surrogate proteins as targets for small-molecule inhibitor discovery and to exemplify this approach in the development of inhibitors against the PPI between the recombinase RAD51 and tumour suppressor BRCA2. As human RAD51 has proved impossible to produce in a form that is compatible with the requirements of fragment-based drug discovery, we have developed a surrogate protein system using RadA from Pyrococcus furiosus. Using a monomerised RadA as our starting point, we have adopted two parallel and mutually instructive approaches to mimic the human enzyme: firstly by mutating RadA to increase sequence identity with RAD51 in the BRC repeat binding sites, and secondly by generating a chimeric archaeal human protein. Both approaches generate proteins that interact with a fourth BRC repeat with affinity and stoichiometry comparable to human RAD51. Stepwise humanisation has also allowed us to elucidate the determinants of RAD51 binding to BRC repeats and the contributions of key interacting residues to this interaction. These surrogate proteins have enabled the development of biochemical and biophysical assays in our ongoing fragment-based small-molecule inhibitor programme and they have allowed us to determine hundreds of liganded structures in support of our structure-guided design process, demonstrating the feasibility and advantages of using archeal surrogates to overcome difficulties in handling human proteins.
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Affiliation(s)
- Tommaso Moschetti
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Timothy Sharpe
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Gerhard Fischer
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
| | - May E. Marsh
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Hong Kin Ng
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Matthew Morgan
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Duncan E. Scott
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Tom L. Blundell
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Ashok R. Venkitaraman
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
| | - John Skidmore
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Chris Abell
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Marko Hyvönen
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK,Corresponding author.
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26
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Onaka AT, Toyofuku N, Inoue T, Okita AK, Sagawa M, Su J, Shitanda T, Matsuyama R, Zafar F, Takahashi TS, Masukata H, Nakagawa T. Rad51 and Rad54 promote noncrossover recombination between centromere repeats on the same chromatid to prevent isochromosome formation. Nucleic Acids Res 2016; 44:10744-10757. [PMID: 27697832 PMCID: PMC5159554 DOI: 10.1093/nar/gkw874] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 09/06/2016] [Accepted: 09/21/2016] [Indexed: 12/14/2022] Open
Abstract
Centromeres consist of DNA repeats in many eukaryotes. Non-allelic homologous recombination (HR) between them can result in gross chromosomal rearrangements (GCRs). In fission yeast, Rad51 suppresses isochromosome formation that occurs between inverted repeats in the centromere. However, how the HR enzyme prevents homology-mediated GCRs remains unclear. Here, we provide evidence that Rad51 with the aid of the Swi/Snf-type motor protein Rad54 promotes non-crossover recombination between centromere repeats to prevent isochromosome formation. Mutations in Rad51 and Rad54 epistatically increased the rates of isochromosome formation and chromosome loss. In sharp contrast, these mutations decreased gene conversion between inverted repeats in the centromere. Remarkably, analysis of recombinant DNAs revealed that rad51 and rad54 increase the proportion of crossovers. In the absence of Rad51, deletion of the structure-specific endonuclease Mus81 decreased both crossovers and isochromosomes, while the cdc27/pol32-D1 mutation, which impairs break-induced replication, did not. We propose that Rad51 and Rad54 promote non-crossover recombination between centromere repeats on the same chromatid, thereby suppressing crossover between non-allelic repeats on sister chromatids that leads to chromosomal rearrangements. Furthermore, we found that Rad51 and Rad54 are required for gene silencing in centromeres, suggesting that HR also plays a role in the structure and function of centromeres.
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Affiliation(s)
- Atsushi T Onaka
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Naoko Toyofuku
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Takahiro Inoue
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Akiko K Okita
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Minami Sagawa
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Jie Su
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Takeshi Shitanda
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Rei Matsuyama
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Faria Zafar
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Tatsuro S Takahashi
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Hisao Masukata
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Takuro Nakagawa
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
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27
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Short JM, Liu Y, Chen S, Soni N, Madhusudhan MS, Shivji MKK, Venkitaraman AR. High-resolution structure of the presynaptic RAD51 filament on single-stranded DNA by electron cryo-microscopy. Nucleic Acids Res 2016; 44:9017-9030. [PMID: 27596592 PMCID: PMC5100573 DOI: 10.1093/nar/gkw783] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 08/24/2016] [Indexed: 12/21/2022] Open
Abstract
Homologous DNA recombination (HR) by the RAD51 recombinase enables error-free DNA break repair. To execute HR, RAD51 first forms a presynaptic filament on single-stranded (ss) DNA, which catalyses pairing with homologous double-stranded (ds) DNA. Here, we report a structure for the presynaptic human RAD51 filament at 3.5–5.0Å resolution using electron cryo-microscopy. RAD51 encases ssDNA in a helical filament of 103Å pitch, comprising 6.4 protomers per turn, with a rise of 16.1Å and a twist of 56.2°. Inter-protomer distance correlates with rotation of an α-helical region in the core catalytic domain that is juxtaposed to ssDNA, suggesting how the RAD51–DNA interaction modulates protomer spacing and filament pitch. We map Fanconi anaemia-like disease-associated RAD51 mutations, clarifying potential phenotypes. We predict binding sites on the presynaptic filament for two modules present in each BRC repeat of the BRCA2 tumour suppressor, a critical HR mediator. Structural modelling suggests that changes in filament pitch mask or expose one binding site with filament-inhibitory potential, rationalizing the paradoxical ability of the BRC repeats to either stabilize or inhibit filament formation at different steps during HR. Collectively, our findings provide fresh insight into the structural mechanism of HR and its dysregulation in human disease.
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Affiliation(s)
- Judith M Short
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
| | - Yang Liu
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
| | - Shaoxia Chen
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Neelesh Soni
- Indian Institute of Science, Education & Research, Dr Homi Babha Road, Pune 411 008, India
| | - Mallur S Madhusudhan
- Indian Institute of Science, Education & Research, Dr Homi Babha Road, Pune 411 008, India.,Bioinformatics Institute, A*STAR, 30 Biopolis Drive, 138671 Singapore
| | - Mahmud K K Shivji
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
| | - Ashok R Venkitaraman
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
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28
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Martinez JS, Baldeyron C, Carreira A. Molding BRCA2 function through its interacting partners. Cell Cycle 2016; 14:3389-95. [PMID: 26566862 DOI: 10.1080/15384101.2015.1093702] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The role of the tumor suppressor BRCA2 has been shaped over 2 decades thanks to the discovery of its protein and nucleic acid partners, biochemical and structural studies of the protein, and the functional evaluation of germline variants identified in breast cancer patients. Yet, the pathogenic and functional effect of many germline mutations in BRCA2 remains undetermined, and the heterogeneity of BRCA2-associated tumors challenges the identification of causative variants that drive tumorigenesis. In this review, we propose an overview of the established and emerging interacting partners and functional pathways attributed to BRCA2, and we speculate on how variants altering these functions may contribute to cancer susceptibility.
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Affiliation(s)
- Juan S Martinez
- a Institut Curie; Centre de Recherche ; Orsay , France.,b CNRS UMR3348; Genotoxic Stress and Cancer; Centre Universitaire ; Orsay , France
| | - Céline Baldeyron
- a Institut Curie; Centre de Recherche ; Orsay , France.,b CNRS UMR3348; Genotoxic Stress and Cancer; Centre Universitaire ; Orsay , France
| | - Aura Carreira
- a Institut Curie; Centre de Recherche ; Orsay , France.,b CNRS UMR3348; Genotoxic Stress and Cancer; Centre Universitaire ; Orsay , France
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Danforth DN. Genomic Changes in Normal Breast Tissue in Women at Normal Risk or at High Risk for Breast Cancer. BREAST CANCER-BASIC AND CLINICAL RESEARCH 2016; 10:109-46. [PMID: 27559297 PMCID: PMC4990153 DOI: 10.4137/bcbcr.s39384] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 04/17/2016] [Accepted: 04/19/2016] [Indexed: 12/12/2022]
Abstract
Sporadic breast cancer develops through the accumulation of molecular abnormalities in normal breast tissue, resulting from exposure to estrogens and other carcinogens beginning at adolescence and continuing throughout life. These molecular changes may take a variety of forms, including numerical and structural chromosomal abnormalities, epigenetic changes, and gene expression alterations. To characterize these abnormalities, a review of the literature has been conducted to define the molecular changes in each of the above major genomic categories in normal breast tissue considered to be either at normal risk or at high risk for sporadic breast cancer. This review indicates that normal risk breast tissues (such as reduction mammoplasty) contain evidence of early breast carcinogenesis including loss of heterozygosity, DNA methylation of tumor suppressor and other genes, and telomere shortening. In normal tissues at high risk for breast cancer (such as normal breast tissue adjacent to breast cancer or the contralateral breast), these changes persist, and are increased and accompanied by aneuploidy, increased genomic instability, a wide range of gene expression differences, development of large cancerized fields, and increased proliferation. These changes are consistent with early and long-standing exposure to carcinogens, especially estrogens. A model for the breast carcinogenic pathway in normal risk and high-risk breast tissues is proposed. These findings should clarify our understanding of breast carcinogenesis in normal breast tissue and promote development of improved methods for risk assessment and breast cancer prevention in women.
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Affiliation(s)
- David N Danforth
- Surgery Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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Abstract
Human cells have numerous repair mechanisms to counteract various insults incurred on the DNA. Any mutation in these repair mechanisms can lead to accumulation of DNA errors and carcinogenesis. This review aims to discuss the therapeutic options in the two most common DNA repair deficient cancer syndromes, namely Lynch syndrome (hereditary non-polyposis colorectal cancer) and breast cancer susceptibility gene (BRCA) associated ovarian and breast cancer. Deficiency in DNA repair mechanisms renders these tumors with increased sensitivity to platinum agents. There has been increasing amount of information on the utility of the defects in DNA repair as targets for cancer therapy in these syndromes. Novel therapies like poly (ADP-ribose) polymerase (PARP) inhibitors are one of such example where the induction of double stranded breaks in DNA leads to tumoricidal effect in patients with homologous DNA repair deficiency. Interestingly, patients with DNA repair deficiencies tend to have a more favorable prognosis than sporadic malignancies. In microsatellite high colorectal cancer patients, this has been attributed to increased recruitment of CD8+ T lymphocytes in tumor microenvironment. However, these tumors are able to limit the host immune response by activation of immune checkpoints that seem like attractive targets of therapy in the future.
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Affiliation(s)
- Gaurav Goyal
- />Department of Internal Medicine, CHI Health Creighton University Medical Center, Omaha, NE USA
| | - Tiffany Fan
- />Class of 2017, Creighton University School of Medicine, Omaha, NE USA
| | - Peter Todd Silberstein
- />Division of Hematology/Oncology, CHI Health Creighton University Medical Center and VA Nebraska-Western Iowa Health Care System, Omaha, NE USA
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31
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Decker B, Karyadi DM, Davis BW, Karlins E, Tillmans LS, Stanford JL, Thibodeau SN, Ostrander EA. Biallelic BRCA2 Mutations Shape the Somatic Mutational Landscape of Aggressive Prostate Tumors. Am J Hum Genet 2016; 98:818-829. [PMID: 27087322 PMCID: PMC4863563 DOI: 10.1016/j.ajhg.2016.03.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 03/02/2016] [Indexed: 01/07/2023] Open
Abstract
To identify clinically important molecular subtypes of prostate cancer (PCa), we characterized the somatic landscape of aggressive tumors via deep, whole-genome sequencing. In our discovery set of ten tumor/normal subject pairs with Gleason scores of 8-10 at diagnosis, coordinated analysis of germline and somatic variants, including single-nucleotide variants, indels, and structural variants, revealed biallelic BRCA2 disruptions in a subset of samples. Compared to the other samples, the PCa BRCA2-deficient tumors exhibited a complex and highly specific mutation signature, featuring a 2.88-fold increased somatic mutation rate, depletion of context-specific C>T substitutions, and an enrichment for deletions, especially those longer than 10 bp. We next performed a BRCA2 deficiency-targeted reanalysis of 150 metastatic PCa tumors, and each of the 18 BRCA2-mutated samples recapitulated the BRCA2 deficiency-associated mutation signature, underscoring the potent influence of these lesions on somatic mutagenesis and tumor evolution. Among all 21 individuals with BRCA2-deficient tumors, only about half carried deleterious germline alleles. Importantly, the somatic mutation signature in tumors with one germline and one somatic risk allele was indistinguishable from those with purely somatic mutations. Our observations clearly demonstrate that BRCA2-disrupted tumors represent a unique and clinically relevant molecular subtype of aggressive PCa, highlighting both the promise and utility of this mutation signature as a prognostic and treatment-selection biomarker. Further, any test designed to leverage BRCA2 status as a biomarker for PCa must consider both germline and somatic mutations and all types of deleterious mutations.
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Affiliation(s)
- Brennan Decker
- Cancer Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA; Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK
| | - Danielle M Karyadi
- Cancer Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
| | - Brian W Davis
- Cancer Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
| | - Eric Karlins
- Cancer Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
| | - Lori S Tillmans
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA
| | - Janet L Stanford
- Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Stephen N Thibodeau
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA
| | - Elaine A Ostrander
- Cancer Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA.
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Saha S, Mandal P, Ganguly S, Jana D, Ayaz A, Banerjee A, Chouhan R, Sarkar DK. Decreased Expression of BRCA2 Accelerates Sporadic Breast Cancer Progression. Indian J Surg Oncol 2015; 6:378-383. [PMID: 27065665 PMCID: PMC4809839 DOI: 10.1007/s13193-015-0449-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 07/24/2015] [Indexed: 10/23/2022] Open
Abstract
Human tumor suppressor BRCA2 has been known to function in the repair of DNA double strand break. Germ line mutation in BRCA genes predisposes individuals to familial breast and ovarian cancer. The aim of present study was to characterize the implication of BRCA2 expression in cases of non - hereditary (sporadic) breast cancer. Female breast cancer patients aged between 20 and 75 years who underwent surgery were randomly selected. Patients with Stage IV disease at time of primary diagnosis or previous history of any other malignancy other than breast carcinoma or undergoing neoadjuvant chemotherapy were excluded from the study. Total 48 patients full filled these criteria. Patients were treated with either modified radical mastectomy or breast conservation therapy. Concentration of BRCA2 was measured by Sandwiched method of ELISA. Immunohistochemistry was used to determine the hormonal receptor status. Stage of the disease was not found to have any significant correlation on the BRCA2 expression. In patients with higher grade of tumors the level of BRCA2 expression was found to be low. Decreased expression of BRCA2 was found to be triple negative, had aggressive features and associated with higher chances of axillary metastasis. Genetic instability caused by decreased expression of BRCA2 could trigger mutations in sporadic breast cancer cases and mutations in turn leads to uncontrolled proliferation and invasive growth.
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Affiliation(s)
- Soumi Saha
- Departement of General Surgery, IPGME&R/SSKMH, 244, A.J.C Bose Road, 700020 Kolkata, India
| | - Pranab Mandal
- Departement of General Surgery, IPGME&R/SSKMH, 244, A.J.C Bose Road, 700020 Kolkata, India
| | - Suvro Ganguly
- Departement of General Surgery, IPGME&R/SSKMH, 244, A.J.C Bose Road, 700020 Kolkata, India
| | - Debarshi Jana
- Departement of General Surgery, IPGME&R/SSKMH, 244, A.J.C Bose Road, 700020 Kolkata, India
| | - Asif Ayaz
- Departement of General Surgery, IPGME&R/SSKMH, 244, A.J.C Bose Road, 700020 Kolkata, India
| | - Abhirup Banerjee
- Departement of General Surgery, IPGME&R/SSKMH, 244, A.J.C Bose Road, 700020 Kolkata, India
| | - Rahul Chouhan
- Departement of General Surgery, IPGME&R/SSKMH, 244, A.J.C Bose Road, 700020 Kolkata, India
| | - Diptendra Kumar Sarkar
- Departement of General Surgery, IPGME&R/SSKMH, 244, A.J.C Bose Road, 700020 Kolkata, India
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Cyclin D1 promotes BRCA2-Rad51 interaction by restricting cyclin A/B-dependent BRCA2 phosphorylation. Oncogene 2015; 35:2815-23. [PMID: 26387543 DOI: 10.1038/onc.2015.354] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 07/23/2015] [Accepted: 08/17/2015] [Indexed: 12/15/2022]
Abstract
BRCA2 has an important role in the maintenance of genome stability by interacting with RAD51 recombinase through its C-terminal domain. This interaction is abrogated by cyclin A-CDK2-mediated phosphorylation of BRCA2 at serine 3291 (Ser3291). Recently, we showed that cyclin D1 facilitates RAD51 recruitment to BRCA2-containing DNA repair foci, and that downregulation of cyclin D1 leads to inefficient homologous-mediated DNA repair. Here, we demonstrate that cyclin D1, via amino acids 20-90, interacts with the C-terminal domain of BRCA2, and that this interaction is increased in response to DNA damage. Interestingly, CDK4-cyclin D1 does not phosphorylate Ser3291. Instead, cyclin D1 bars cyclin A from the C-terminus of BRCA2, prevents cyclin A-CDK2-dependent Ser3291 phosphorylation and facilitates RAD51 binding to the C-terminal domain of BRCA2. These findings indicate that the interplay between cyclin D1 and other cyclins such as cyclin A regulates DNA integrity through RAD51 interaction with the BRCA2 C-terminal domain.
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Scumaci D, Tammè L, Fiumara CV, Pappaianni G, Concolino A, Leone E, Faniello MC, Quaresima B, Ricevuto E, Costanzo FS, Cuda G. Plasma Proteomic Profiling in Hereditary Breast Cancer Reveals a BRCA1-Specific Signature: Diagnostic and Functional Implications. PLoS One 2015; 10:e0129762. [PMID: 26061043 PMCID: PMC4465499 DOI: 10.1371/journal.pone.0129762] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 05/13/2015] [Indexed: 12/16/2022] Open
Abstract
Background Breast cancer (BC) is a leading cause of death among women. Among the major risk factors, an important role is played by familial history of BC. Germ-line mutations in BRCA1/2 genes account for most of the hereditary breast and/or ovarian cancers. Gene expression profiling studies have disclosed specific molecular signatures for BRCA1/2-related breast tumors as compared to sporadic cases, which might help diagnosis and clinical follow-up. Even though, a clear hallmark of BRCA1/2-positive BC is still lacking. Many diseases are correlated with quantitative changes of proteins in body fluids. Plasma potentially carries important information whose knowledge could help to improve early disease detection, prognosis, and response to therapeutic treatments. The aim of this study was to develop a comprehensive approach finalized to improve the recovery of specific biomarkers from plasma samples of subjects affected by hereditary BC. Methods To perform this analysis, we used samples from patients belonging to highly homogeneous population previously reported. Depletion of high abundant plasma proteins, 2D gel analysis, liquid chromatography-tandem mass spectrometry (LC-MS/MS) and bioinformatics analysis were used into an integrated approach to investigate tumor-specific changes in the plasma proteome of BC patients and healthy family members sharing the same BRCA1 gene founder mutation (5083del19), previously reported by our group, with the aim to identify specific signatures. Results The comparative analysis of the experimental results led to the identification of gelsolin as the most promising biomarker. Conclusions Further analyses, performed using a panel of breast cancer cell lines, allowed us to further elucidate the signaling network that might modulate the expression of gelsolin in breast cancer.
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Affiliation(s)
- Domenica Scumaci
- Dpt. of Experimental and Clinical Medicine, Magna Græcia University of Catanzaro, Salvatore Venuta University Campus, Catanzaro, Italy
- * E-mail:
| | - Laura Tammè
- Dpt. of Experimental and Clinical Medicine, Magna Græcia University of Catanzaro, Salvatore Venuta University Campus, Catanzaro, Italy
| | - Claudia Vincenza Fiumara
- Dpt. of Experimental and Clinical Medicine, Magna Græcia University of Catanzaro, Salvatore Venuta University Campus, Catanzaro, Italy
| | - Giusi Pappaianni
- Dpt. of Experimental and Clinical Medicine, Magna Græcia University of Catanzaro, Salvatore Venuta University Campus, Catanzaro, Italy
| | - Antonio Concolino
- Dpt. of Experimental and Clinical Medicine, Magna Græcia University of Catanzaro, Salvatore Venuta University Campus, Catanzaro, Italy
| | - Emanuela Leone
- Dpt. of Experimental and Clinical Medicine, Magna Græcia University of Catanzaro, Salvatore Venuta University Campus, Catanzaro, Italy
| | - Maria Concetta Faniello
- Dpt. of Experimental and Clinical Medicine, Magna Græcia University of Catanzaro, Salvatore Venuta University Campus, Catanzaro, Italy
| | - Barbara Quaresima
- Dpt. of Experimental and Clinical Medicine, Magna Græcia University of Catanzaro, Salvatore Venuta University Campus, Catanzaro, Italy
| | - Enrico Ricevuto
- Medical Oncology, S. Salvatore Hospital, University of L'Aquila, L'Aquila, Italy
| | - Francesco Saverio Costanzo
- Dpt. of Experimental and Clinical Medicine, Magna Græcia University of Catanzaro, Salvatore Venuta University Campus, Catanzaro, Italy
| | - Giovanni Cuda
- Dpt. of Experimental and Clinical Medicine, Magna Græcia University of Catanzaro, Salvatore Venuta University Campus, Catanzaro, Italy
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Systemic Treatment Considerations for Women with BRCA1/2-Associated Breast Cancer. CURRENT BREAST CANCER REPORTS 2014. [DOI: 10.1007/s12609-014-0156-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Rosa26-GFP direct repeat (RaDR-GFP) mice reveal tissue- and age-dependence of homologous recombination in mammals in vivo. PLoS Genet 2014; 10:e1004299. [PMID: 24901438 PMCID: PMC4046920 DOI: 10.1371/journal.pgen.1004299] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 02/24/2014] [Indexed: 01/15/2023] Open
Abstract
Homologous recombination (HR) is critical for the repair of double strand breaks and broken replication forks. Although HR is mostly error free, inherent or environmental conditions that either suppress or induce HR cause genomic instability. Despite its importance in carcinogenesis, due to limitations in our ability to detect HR in vivo, little is known about HR in mammalian tissues. Here, we describe a mouse model in which a direct repeat HR substrate is targeted to the ubiquitously expressed Rosa26 locus. In the Rosa26Direct Repeat-GFP (RaDR-GFP) mice, HR between two truncated EGFP expression cassettes can yield a fluorescent signal. In-house image analysis software provides a rapid method for quantifying recombination events within intact tissues, and the frequency of recombinant cells can be evaluated by flow cytometry. A comparison among 11 tissues shows that the frequency of recombinant cells varies by more than two orders of magnitude among tissues, wherein HR in the brain is the lowest. Additionally, de novo recombination events accumulate with age in the colon, showing that this mouse model can be used to study the impact of chronic exposures on genomic stability. Exposure to N-methyl-N-nitrosourea, an alkylating agent similar to the cancer chemotherapeutic temozolomide, shows that the colon, liver and pancreas are susceptible to DNA damage-induced HR. Finally, histological analysis of the underlying cell types reveals that pancreatic acinar cells and liver hepatocytes undergo HR and also that HR can be specifically detected in colonic somatic stem cells. Taken together, the RaDR-GFP mouse model provides new understanding of how tissue and age impact susceptibility to HR, and enables future studies of genetic, environmental and physiological factors that modulate HR in mammals. Cancer is a disease of the genome, caused by accumulated genetic changes, such as point mutations and large-scale sequence rearrangements. Homologous recombination (HR) is a critical DNA repair pathway. While generally accurate, HR between misaligned sequences or between homologous chromosomes can lead to insertions, deletions, and loss of heterozygosity, all of which are known to promote cancer. Indeed, most cancers harbor sequence changes caused by HR, and genetic and environmental conditions that induce or suppress HR are often carcinogenic. To enable studies of HR in vivo, we created the Rosa26 Direct Repeat-Green Fluorescent Protein (RaDR-GFP) mice that carry an integrated transgenic recombination reporter targeted to the ubiquitously expressed Rosa26 locus. Being able to detect recombinant cells by fluorescence reveals that the frequency of recombination is highly variable among tissues. Furthermore, new recombination events accumulate over time, which contributes to our understanding of why our risk for cancer increases with age. This mouse model provides new understanding of this important DNA repair pathway in vivo, and also enables future studies of genetic, environmental and physiological factors that impact the risk of HR-induced sequence rearrangements in vivo.
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37
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Pothuri B. BRCA1- and BRCA2-related mutations: therapeutic implications in ovarian cancer. Ann Oncol 2014; 24 Suppl 8:viii22-viii27. [PMID: 24131965 DOI: 10.1093/annonc/mdt307] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Ovarian cancer is the deadliest among gynecologic cancers. Hereditary cancer related to BRCA1/2 gene mutations account for ~10%-12% of ovarian cancers. The BRCA1/2 proteins are important in homologous recombination (HR) repair of DNA. Patients with BRCA1/2 mutations have been reported to have improved chemosensitivity to platinum agents, longer disease-free intervals, and longer survivals than nonhereditary counterparts. Recent interest in poly(ADP-ribosyl) polymerase (PARP) proteins which are key components of base excision repair, has led to the development of PARP inhibitors; tumors arising in BRCA1/2 mutation carriers and/or with HR deficiency (HRD) are particularly sensitive to the action of these drugs. As 60%-80% of all advanced ovarian cancers are high-grade serous type, exhibiting HRD in at least 50% (referred as BRCAness) future antitumor strategies may depend on identifying these defects through molecular testing. Once HRD becomes amenable to routine testing, a larger group of ovarian cancer patients than are currently considered for PARP inhibitor trials, may benefit from such targeted therapy.
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Affiliation(s)
- B Pothuri
- Department of Obstetrics and Gynecology, Division of Gynecologic Oncology, NYU School of Medicine, New York, USA
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38
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Abstract
Germline mutations in BRCA1 and BRCA2 predispose to common human malignancies, most notably tumors of the breast and ovaries. The proteins encoded by these genes have been implicated in a plethora of biochemical interactions and biological functions, confounding attempts to coherently explain how their inactivation promotes carcinogenesis. Here, I argue that tumor suppression by BRCA1 and BRCA2 originates from their fundamental role in controlling the assembly and activity of macromolecular complexes that monitor chromosome duplication, maintenance, and segregation across the cell cycle. A tumor-suppressive role for the BRCA proteins as "chromosome custodians" helps to explain the clinical features of cancer susceptibility after their inactivation, provides foundations for the rational therapy of BRCA-deficient cancers, and offers general insights into the mechanisms opposing early steps in human carcinogenesis.
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Affiliation(s)
- Ashok R Venkitaraman
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
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39
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Jacq X, Kemp M, Martin NMB, Jackson SP. Deubiquitylating enzymes and DNA damage response pathways. Cell Biochem Biophys 2014; 67:25-43. [PMID: 23712866 PMCID: PMC3756857 DOI: 10.1007/s12013-013-9635-3] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Covalent post-translational modification of proteins by ubiquitin and ubiquitin-like factors has emerged as a general mechanism to regulate myriad intra-cellular processes. The addition and removal of ubiquitin or ubiquitin-like proteins from factors has recently been demonstrated as a key mechanism to modulate DNA damage response (DDR) pathways. It is thus, timely to evaluate the potential for ubiquitin pathway enzymes as DDR drug targets for therapeutic intervention. The synthetic lethal approach provides exciting opportunities for the development of targeted therapies to treat cancer: most tumours have lost critical DDR pathways, and thus rely more heavily on the remaining pathways, while normal tissues are still equipped with all DDR pathways. Here, we review key deubiquitylating enzymes (DUBs) involved in DDR pathways, and describe how targeting DUBs may lead to selective therapies to treat cancer patients.
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Affiliation(s)
- Xavier Jacq
- MISSION Therapeutics Ltd, Babraham Research Campus, Cambridge, CB22 3AT, UK.
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Cassidy LD, Liau SS, Venkitaraman AR. Chromosome instability and carcinogenesis: insights from murine models of human pancreatic cancer associated with BRCA2 inactivation. Mol Oncol 2014; 8:161-8. [PMID: 24268522 PMCID: PMC3989051 DOI: 10.1016/j.molonc.2013.10.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Revised: 10/07/2013] [Accepted: 10/13/2013] [Indexed: 01/01/2023] Open
Abstract
Chromosomal instability is a hallmark of human cancer cells, but its role in carcinogenesis remains poorly resolved. Insights into this role have emerged from studies on the tumour suppressor BRCA2, whose inactivation in human cancers causes chromosomal instability through the loss of essential functions of the BRCA2 protein in the normal mechanisms responsible for the replication, repair and segregation of DNA during cell division. Humans who carry heterozygous germline mutations in the BRCA2 gene are highly predisposed to cancers of the breast, ovary, pancreas, prostate and other tissues. Here, we review recent studies that describe genetically engineered mouse models (GEMMs) for pancreatic cancer associated with BRCA2 mutations. These studies not only surprisingly show that BRCA2 does not follow the classical Knudson "two hit" paradigm for tumour suppression, but also highlight features of the interplay between TP53 inactivation and carcinogenesis in the context of BRCA2 deficiency. Thus, the models reveal novel aspects of cancer evolution in carriers of germline BRCA2 mutations, provide new insights into the tumour suppressive role of BRCA2, and establish valuable new preclinical settings for testing approaches to pancreatic cancer therapy; together, these features emphasize the value of GEMMs in cancer research.
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Affiliation(s)
- Liam D Cassidy
- University of Cambridge, Medical Research Council Cancer Cell Unit, Hutchison/MRC Research Centre, Hills Road, Cambridge CB2 0XZ, United Kingdom
| | - Siong-Seng Liau
- University of Cambridge, Medical Research Council Cancer Cell Unit, Hutchison/MRC Research Centre, Hills Road, Cambridge CB2 0XZ, United Kingdom
| | - Ashok R Venkitaraman
- University of Cambridge, Medical Research Council Cancer Cell Unit, Hutchison/MRC Research Centre, Hills Road, Cambridge CB2 0XZ, United Kingdom.
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Venkitaraman AR. Tumour suppressor mechanisms in the control of chromosome stability: insights from BRCA2. Mol Cells 2014; 37:95-9. [PMID: 24598993 PMCID: PMC3935635 DOI: 10.14348/molcells.2014.2346] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 11/23/2013] [Indexed: 12/13/2022] Open
Abstract
Cancer is unique amongst human diseases in that its cellular manifestations arise and evolve through the acquisition of somatic alterations in the genome. In particular, instability in the number and structure of chromosomes is a near-universal feature of the genomic alterations associated with epithelial cancers, and is triggered by the inactivation of tumour suppressor mechanisms that preserve chromosome integrity in normal cells. The nature of these mechanisms, and how their inactivation promotes carcinogenesis, remains enigmatic. I will review recent work from our laboratory on the tumour suppressor BRCA2 that addresses these issues, focusing on new insights into cancer pathogenesis and therapy that are emerging from improved understanding of the molecular basis of chromosomal instability in BRCA2-deficient cancer cells.
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Affiliation(s)
- Ashok R. Venkitaraman
- University of Cambridge, Medical Research Council Cancer Unit, Hutchison/MRC Research Centre, Hills Road, Cambridge CB2 0XZ,
United Kingdom
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42
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Wickramasinghe VO, Savill JM, Chavali S, Jonsdottir AB, Rajendra E, Grüner T, Laskey RA, Babu MM, Venkitaraman AR. Human inositol polyphosphate multikinase regulates transcript-selective nuclear mRNA export to preserve genome integrity. Mol Cell 2013; 51:737-50. [PMID: 24074953 DOI: 10.1016/j.molcel.2013.08.031] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 06/20/2013] [Accepted: 08/14/2013] [Indexed: 01/08/2023]
Abstract
Messenger RNA (mRNA) export from the nucleus is essential for eukaryotic gene expression. Here we identify a transcript-selective nuclear export mechanism affecting certain human transcripts, enriched for functions in genome duplication and repair, controlled by inositol polyphosphate multikinase (IPMK), an enzyme catalyzing inositol polyphosphate and phosphoinositide turnover. We studied transcripts encoding RAD51, a protein essential for DNA repair by homologous recombination (HR), to characterize the mechanism underlying IPMK-regulated mRNA export. IPMK depletion or catalytic inactivation selectively decreases RAD51 protein abundance and the nuclear export of RAD51 mRNA, thereby impairing HR. Recognition of a sequence motif in the untranslated region of RAD51 transcripts by the mRNA export factor ALY requires IPMK. Phosphatidylinositol (3,4,5)-trisphosphate (PIP3), an IPMK product, restores ALY recognition in IPMK-depleted cell extracts, suggesting a mechanism underlying transcript selection. Our findings implicate IPMK in a transcript-selective mRNA export pathway controlled by phosphoinositide turnover that preserves genome integrity in humans.
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Affiliation(s)
- Vihandha O Wickramasinghe
- The Medical Research Council Cancer Unit, Hutchison/MRC Research Centre, Hills Road, Cambridge CB2 0XZ, UK
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Trenaman A, Hartley C, Prorocic M, Passos-Silva DG, van den Hoek M, Nechyporuk-Zloy V, Machado CR, McCulloch R. Trypanosoma brucei BRCA2 acts in a life cycle-specific genome stability process and dictates BRC repeat number-dependent RAD51 subnuclear dynamics. Nucleic Acids Res 2012; 41:943-60. [PMID: 23222131 PMCID: PMC3553974 DOI: 10.1093/nar/gks1192] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Trypanosoma brucei survives in mammals through antigenic variation, which is driven by RAD51-directed homologous recombination of Variant Surface Glycoproteins (VSG) genes, most of which reside in a subtelomeric repository of >1000 silent genes. A key regulator of RAD51 is BRCA2, which in T. brucei contains a dramatic expansion of a motif that mediates interaction with RAD51, termed the BRC repeats. BRCA2 mutants were made in both tsetse fly-derived and mammal-derived T. brucei, and we show that BRCA2 loss has less impact on the health of the former. In addition, we find that genome instability, a hallmark of BRCA2 loss in other organisms, is only seen in mammal-derived T. brucei. By generating cells expressing BRCA2 variants with altered BRC repeat numbers, we show that the BRC repeat expansion is crucial for RAD51 subnuclear dynamics after DNA damage. Finally, we document surprisingly limited co-localization of BRCA2 and RAD51 in the T. brucei nucleus, and we show that BRCA2 mutants display aberrant cell division, revealing a function distinct from BRC-mediated RAD51 interaction. We propose that BRCA2 acts to maintain the huge VSG repository of T. brucei, and this function has necessitated the evolution of extensive RAD51 interaction via the BRC repeats, allowing re-localization of the recombinase to general genome damage when needed.
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Affiliation(s)
- Anna Trenaman
- The Wellcome Trust Centre for Molecular Parasitology, College of Medical Veterinary and Life Sciences, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davies Building, 120 University Place, Glasgow G12 8TA, UK
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Frankenberg-Schwager M, Gregus A. Chromosomal instability induced by mammography X-rays in primary human fibroblasts from BRCA1 and BRCA2 mutation carriers. Int J Radiat Biol 2012; 88:846-57. [PMID: 22788243 DOI: 10.3109/09553002.2012.711500] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
PURPOSE Mammography X-rays are known to induce DNA double-strand breaks (DSB) whose error-free recombinational repair requires the function of the tumour repressor genes BRCA1 (breast-cancer-associated gene 1) and BRCA2 (breast-cancer-associated gene 2). Since un- or misrepaired DSB lead to chromosomal anomalies which may promote the development of breast cancer, we have studied the potential of mammography X-rays for immediate and delayed induction of chromosomal anomalies in human primary fibroblasts from BRCA1 and BRCA2 mutation carriers. MATERIALS AND METHODS Primary human fibroblasts from three BRCA1, three BRCA2 mutation carriers, one BRCA2-deficient fanconi anemia (FA) patient and three normal individuals were exposed to various doses of mammography X-rays. Chromosomal anomalies at first mitosis and at several population doublings post-irradiation were assayed (Giemsa staining and Fish [fluorescence in situ hybridization]). RESULTS No effect of the BRCA mutation status was observed on survival curves after exposure to mammography X-rays and on the dose-dependent increase of chromosomal anomalies at first mitosis post-irradiation. In contrast, several population doublings after exposure to a low dose of only 0.5 Gy chromosomal instability, manifested as gross chromosomal rearrangements and aneuploidy, had developed in BRCA2-deficient FA fibroblasts and in some - but not all - BRCA heterozygous fibroblasts. CONCLUSIONS Low doses of mammography X-rays have the potential to induce chromosomal instability in fibroblasts from BRCA mutation carriers: Cells exhibit gross chromosomal rearrangements and aneuploidy similar to those observed in breast cancer cells. These results suggest that for women carrying a BRCA mutation early and frequent screening with mammography X-rays may not be the method of choice to detect breast cancer.
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Magwood AC, Mundia MM, Baker MD. High levels of wild-type BRCA2 suppress homologous recombination. J Mol Biol 2012; 421:38-53. [PMID: 22579622 DOI: 10.1016/j.jmb.2012.05.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 04/23/2012] [Accepted: 05/03/2012] [Indexed: 11/26/2022]
Abstract
Endogenous levels of the BRCA2 (breast cancer susceptibility 2) protein promote homologous recombination by regulating the essential strand exchange protein RAD51. To examine BRCA2 function in homologous recombination, we expressed human BRCA2 in control mouse hybridoma cells, as well as those that were depleted of endogenous Brca2 by small interfering RNA. With moderate human BRCA2 expression, homologous recombination was stimulated. Conversely, a higher level of BRCA2 reduced homologous recombination and DNA-damage-induced Rad51 foci formation. Cells expressing high levels of BRCA2 feature normal growth, increased sensitivity to mitomycin C, and increased illegitimate recombination. BRCA2-overexpressing cells are also characterized by suppression of p53 transcriptional regulation and a corresponding reduction in the expression of the p53-responsive genes Noxa and p21. Notably, in cells expressing high levels of BRCA2, small interfering RNA depletion of human BRCA2 or ectopic expression of Rad51 increases homologous recombination and decreases illegitimate recombination. Thus, high levels of wild-type BRCA2 perturb Rad51-mediated homologous recombination, and relatively normal recombination responses can be restored by rebalancing recombination factors.
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Affiliation(s)
- Alissa C Magwood
- Department of Molecular and Cellular Biology, College of Biological Science, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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Genois MM, Mukherjee A, Ubeda JM, Buisson R, Paquet E, Roy G, Plourde M, Coulombe Y, Ouellette M, Masson JY. Interactions between BRCA2 and RAD51 for promoting homologous recombination in Leishmania infantum. Nucleic Acids Res 2012; 40:6570-84. [PMID: 22505581 PMCID: PMC3413117 DOI: 10.1093/nar/gks306] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In most organisms, the primary function of homologous recombination (HR) is to allow genome protection by the faithful repair of DNA double-strand breaks. The vital step of HR is the search for sequence homology, mediated by the RAD51 recombinase, which is stimulated further by proteins mediators such as the tumor suppressor BRCA2. The biochemical interplay between RAD51 and BRCA2 is unknown in Leishmania or Trypanosoma. Here we show that the Leishmania infantum BRCA2 protein possesses several critical features important for the regulation of DNA recombination at the genetic and biochemical level. A BRCA2 null mutant, generated by gene disruption, displayed genomic instability and gene-targeting defects. Furthermore, cytological studies show that LiRAD51 can no longer localize to the nucleus in this mutant. The Leishmania RAD51 and BRCA2 interact together and the purified proteins bind single-strand DNA. Remarkably, LiBRCA2 is a recombination mediator that stimulates the invasion of a resected DNA double-strand break in an undamaged template by LiRAD51 to form a D-loop structure. Collectively, our data show that LiBRCA2 and LiRAD51 promote HR at the genetic and biochemical level in L. infantum, the causative agent of visceral leishmaniasis.
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Affiliation(s)
- Marie-Michelle Genois
- Genome Stability Laboratory, Laval University Cancer Research Center, Hôtel-Dieu de Québec, 9 McMahon, Québec, G1R 2J6, Canada
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Genome instability mechanisms and the structure of cancer genomes. Curr Opin Genet Dev 2012; 22:10-3. [PMID: 22366532 DOI: 10.1016/j.gde.2012.02.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 02/06/2012] [Indexed: 11/22/2022]
Abstract
Genomic instability is a hallmark of cancer cells, and arises from the aberrations that these cells exhibit in the normal biological mechanisms that repair and replicate the genome, or ensure its accurate segregation during cell division. Increasingly detailed descriptions of cancer genomes have begun to emerge from next-generation sequencing (NGS), providing snapshots of their nature and heterogeneity in different cancers at different stages in their evolution. Here, we attempt to extract from these sequencing studies insights into the role of genome instability mechanisms in carcinogenesis, and to identify challenges impeding further progress.
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Min J, Choi ES, Hwang K, Kim J, Sampath S, Venkitaraman AR, Lee H. The breast cancer susceptibility gene BRCA2 is required for the maintenance of telomere homeostasis. J Biol Chem 2012; 287:5091-101. [PMID: 22187435 PMCID: PMC3281639 DOI: 10.1074/jbc.m111.278994] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2011] [Revised: 12/19/2011] [Indexed: 11/06/2022] Open
Abstract
Inactivating mutations in the breast cancer susceptibility gene BRCA2 cause gross chromosomal rearrangements. Chromosome structural instability in the absence of BRCA2 is thought to result from defective homology-directed DNA repair. Here, we show that BRCA2 links the fidelity of telomere maintenance with genetic integrity. Absence of BRCA2 resulted in signs of dysfunctional telomeres, such as telomere shortening, erosions, and end fusions in proliferating mouse fibroblasts. BRCA2 localized to the telomeres in S phase in an ATR-dependent manner, and its absence resulted in the accumulation of common fragile sites, particularly at the G-rich lagging strand, and increased the telomere sister chromatid exchange in unchallenged cells. The incidence of common fragile sites and telomere sister chromatid exchange increased markedly after treatment with replication inhibitors. Congruently, telomere-induced foci were frequently observed in the absence of Brca2, denoting activation of the DNA damage response and abnormal chromosome end joining. These telomere end fusions constituted a significant portion of chromosome aberrations in Brca2-deficient cells. Our results suggest that BRCA2 is required for telomere homeostasis and may be particularly important for the replication of G-rich telomeric lagging strands.
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Affiliation(s)
- Jaewon Min
- From the Department of Biological Sciences and the Institute of Molecular Biology and Genetics, Seoul National University, 599 Gwanak-Ro, Gwanak-Gu, Seoul 151-742, Korea and
| | - Eun Shik Choi
- From the Department of Biological Sciences and the Institute of Molecular Biology and Genetics, Seoul National University, 599 Gwanak-Ro, Gwanak-Gu, Seoul 151-742, Korea and
| | - Kwangwoo Hwang
- From the Department of Biological Sciences and the Institute of Molecular Biology and Genetics, Seoul National University, 599 Gwanak-Ro, Gwanak-Gu, Seoul 151-742, Korea and
| | - Jimi Kim
- From the Department of Biological Sciences and the Institute of Molecular Biology and Genetics, Seoul National University, 599 Gwanak-Ro, Gwanak-Gu, Seoul 151-742, Korea and
| | - Srihari Sampath
- the Medical Research Council Cancer Cell Unit, Hutchison/Medical Research Council Research Centre, University of Cambridge, Hills Road, Cambridge CB2 0XZ, United Kingdom
| | - Ashok R. Venkitaraman
- the Medical Research Council Cancer Cell Unit, Hutchison/Medical Research Council Research Centre, University of Cambridge, Hills Road, Cambridge CB2 0XZ, United Kingdom
| | - Hyunsook Lee
- From the Department of Biological Sciences and the Institute of Molecular Biology and Genetics, Seoul National University, 599 Gwanak-Ro, Gwanak-Gu, Seoul 151-742, Korea and
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Amunugama R, Fishel R. Homologous Recombination in Eukaryotes. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 110:155-206. [DOI: 10.1016/b978-0-12-387665-2.00007-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Seeliger K, Dukowic-Schulze S, Wurz-Wildersinn R, Pacher M, Puchta H. BRCA2 is a mediator of RAD51- and DMC1-facilitated homologous recombination in Arabidopsis thaliana. THE NEW PHYTOLOGIST 2012; 193:364-75. [PMID: 22077663 DOI: 10.1111/j.1469-8137.2011.03947.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
• Mutations in the breast cancer susceptibility gene 2 (BRCA2) are correlated with hereditary breast cancer in humans. Studies have revealed that mammalian BRCA2 plays crucial roles in DNA repair. Therefore, we wished to define the role of the BRCA2 homologs in Arabidopsis in detail. • As Arabidopsis contains two functional BRCA2 homologs, an Atbrca2 double mutant was generated and analyzed with respect to hypersensitivity to genotoxic agents and recombination frequencies. Cytological studies addressing male and female meiosis were also conducted, and immunolocalization was performed in male meiotic prophase I. • The Atbrca2 double mutant showed hypersensitivity to the cross-linking agent mitomycin C and displayed a dramatic reduction in somatic homologous recombination frequency, especially after double-strand break induction. The loss of AtBRCA2 also led to severe defects in male meiosis and development of the female gametophyte and impeded proper localization of the synaptonemal complex protein AtZYP1 and the recombinases AtRAD51 and AtDMC1. • The results demonstrate that AtBRCA2 is important for both somatic and meiotic homologous recombination. We further show that AtBRCA2 is required for proper meiotic synapsis and mediates the recruitment of AtRAD51 and AtDMC1. Our results suggest that BRCA2 controls single-strand invasion steps during homologous recombination in plants.
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Affiliation(s)
- Katharina Seeliger
- Botanical Institute II, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
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