1
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Orlic-Milacic M, Rothfels K, Matthews L, Wright A, Jassal B, Shamovsky V, Trinh Q, Gillespie ME, Sevilla C, Tiwari K, Ragueneau E, Gong C, Stephan R, May B, Haw R, Weiser J, Beavers D, Conley P, Hermjakob H, Stein LD, D'Eustachio P, Wu G. Pathway-based, reaction-specific annotation of disease variants for elucidation of molecular phenotypes. Database (Oxford) 2024; 2024:baae031. [PMID: 38713862 DOI: 10.1093/database/baae031] [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: 11/08/2023] [Revised: 02/23/2024] [Accepted: 04/01/2024] [Indexed: 05/09/2024]
Abstract
Germline and somatic mutations can give rise to proteins with altered activity, including both gain and loss-of-function. The effects of these variants can be captured in disease-specific reactions and pathways that highlight the resulting changes to normal biology. A disease reaction is defined as an aberrant reaction in which a variant protein participates. A disease pathway is defined as a pathway that contains a disease reaction. Annotation of disease variants as participants of disease reactions and disease pathways can provide a standardized overview of molecular phenotypes of pathogenic variants that is amenable to computational mining and mathematical modeling. Reactome (https://reactome.org/), an open source, manually curated, peer-reviewed database of human biological pathways, in addition to providing annotations for >11 000 unique human proteins in the context of ∼15 000 wild-type reactions within more than 2000 wild-type pathways, also provides annotations for >4000 disease variants of close to 400 genes as participants of ∼800 disease reactions in the context of ∼400 disease pathways. Functional annotation of disease variants proceeds from normal gene functions, described in wild-type reactions and pathways, through disease variants whose divergence from normal molecular behaviors has been experimentally verified, to extrapolation from molecular phenotypes of characterized variants to variants of unknown significance using criteria of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Reactome's data model enables mapping of disease variant datasets to specific disease reactions within disease pathways, providing a platform to infer pathway output impacts of numerous human disease variants and model organism orthologs, complementing computational predictions of variant pathogenicity. Database URL: https://reactome.org/.
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Affiliation(s)
- Marija Orlic-Milacic
- Adaptive Oncology, Ontario Institute for Cancer Research, 661 University Avenue Suite 510, Toronto, ON M5G 0A3, Canada
| | - Karen Rothfels
- Adaptive Oncology, Ontario Institute for Cancer Research, 661 University Avenue Suite 510, Toronto, ON M5G 0A3, Canada
| | - Lisa Matthews
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Adam Wright
- Adaptive Oncology, Ontario Institute for Cancer Research, 661 University Avenue Suite 510, Toronto, ON M5G 0A3, Canada
| | - Bijay Jassal
- Adaptive Oncology, Ontario Institute for Cancer Research, 661 University Avenue Suite 510, Toronto, ON M5G 0A3, Canada
| | - Veronica Shamovsky
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Quang Trinh
- Adaptive Oncology, Ontario Institute for Cancer Research, 661 University Avenue Suite 510, Toronto, ON M5G 0A3, Canada
| | - Marc E Gillespie
- Adaptive Oncology, Ontario Institute for Cancer Research, 661 University Avenue Suite 510, Toronto, ON M5G 0A3, Canada
- College of Pharmacy and Health Sciences, St. John's University, 8000 Utopia Parkway, Queens, NY 11439, USA
| | - Cristoffer Sevilla
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SD, UK
- Open Targets, Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SD, UK
| | - Krishna Tiwari
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SD, UK
| | - Eliot Ragueneau
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SD, UK
| | - Chuqiao Gong
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SD, UK
| | - Ralf Stephan
- Adaptive Oncology, Ontario Institute for Cancer Research, 661 University Avenue Suite 510, Toronto, ON M5G 0A3, Canada
- Institute for Globally Distributed Open Research and Education (IGDORE)
| | - Bruce May
- Adaptive Oncology, Ontario Institute for Cancer Research, 661 University Avenue Suite 510, Toronto, ON M5G 0A3, Canada
| | - Robin Haw
- Adaptive Oncology, Ontario Institute for Cancer Research, 661 University Avenue Suite 510, Toronto, ON M5G 0A3, Canada
| | - Joel Weiser
- Adaptive Oncology, Ontario Institute for Cancer Research, 661 University Avenue Suite 510, Toronto, ON M5G 0A3, Canada
| | - Deidre Beavers
- Department of Medical Informatics and Clinical Epidemiology, Oregon Health and Science University, 3181 S.W. Sam Jackson Park Rd., Portland, OR 97239, USA
| | - Patrick Conley
- Department of Medical Informatics and Clinical Epidemiology, Oregon Health and Science University, 3181 S.W. Sam Jackson Park Rd., Portland, OR 97239, USA
| | - Henning Hermjakob
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SD, UK
- Open Targets, Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SD, UK
| | - Lincoln D Stein
- Adaptive Oncology, Ontario Institute for Cancer Research, 661 University Avenue Suite 510, Toronto, ON M5G 0A3, Canada
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Room 4386, Toronto, ON M5S 1A8, Canada
| | - Peter D'Eustachio
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Guanming Wu
- Department of Medical Informatics and Clinical Epidemiology, Oregon Health and Science University, 3181 S.W. Sam Jackson Park Rd., Portland, OR 97239, USA
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2
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Akahira R, Fukuda K, Shimazu K, Yoshida T, Taguchi D, Shinozaki H, Nanjyo H, Shibata H. Clinical response of pancreatic cancer bearing a germline BRCA2 p.I3169M fs*48 variant for platinum-based drug and PARP inhibitor. Jpn J Clin Oncol 2024; 54:201-205. [PMID: 37956396 PMCID: PMC10849180 DOI: 10.1093/jjco/hyad157] [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: 08/02/2023] [Accepted: 10/26/2023] [Indexed: 11/15/2023] Open
Abstract
Pancreatic cancer is a malignancy with a high mortality rate, accounting for 37 000 people annually in Japan. It is rarely diagnosed in a resectable state, and effective medicines for its advanced stage are scarce. Some pancreatic cancer is hereditary, and ~10% have germline mutations of Breast cancer 1/2 (BRCA1/2). BRCA1/2 are key molecules involved in homologous recombination to repair DNA double-strand break. Platinum-based drugs and poly Adenosine diphosphate ribose (ADP) ribose polymerase inhibitors that induce synthetic lethality would be theoretically effective in patients with loss-of-function mutations in BRCA1/2. Strictly speaking, some discrepancy between the pathogenicity of BRCA1/2 and their drug sensitivity might be expected. Hence, we report that platinum-based anticancer agents and poly ADP ribose polymerase inhibitors were effective against pancreatic cancer bearing BRCA2 p.I3169M fs*48.
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Affiliation(s)
- Risa Akahira
- Department of Clinical Oncology, Graduaste School of Medicine, Akita University, Akita, Japan
| | - Koji Fukuda
- Department of Clinical Oncology, Graduaste School of Medicine, Akita University, Akita, Japan
| | - Kazuhiro Shimazu
- Department of Clinical Oncology, Graduaste School of Medicine, Akita University, Akita, Japan
| | - Taichi Yoshida
- Department of Clinical Oncology, Graduaste School of Medicine, Akita University, Akita, Japan
| | - Daiki Taguchi
- Department of Clinical Oncology, Graduaste School of Medicine, Akita University, Akita, Japan
| | - Hanae Shinozaki
- Department of Clinical Oncology, Graduaste School of Medicine, Akita University, Akita, Japan
| | - Hiroshi Nanjyo
- Department of Pathology, Akita University Hospital, Akita, Japan
| | - Hiroyuki Shibata
- Department of Clinical Oncology, Graduaste School of Medicine, Akita University, Akita, Japan
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3
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Ren X, Yang H, Nierenberg JL, Sun Y, Chen J, Beaman C, Pham T, Nobuhara M, Takagi MA, Narayan V, Li Y, Ziv E, Shen Y. High-throughput PRIME-editing screens identify functional DNA variants in the human genome. Mol Cell 2023; 83:4633-4645.e9. [PMID: 38134886 PMCID: PMC10766087 DOI: 10.1016/j.molcel.2023.11.021] [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: 05/12/2023] [Revised: 10/07/2023] [Accepted: 11/16/2023] [Indexed: 12/24/2023]
Abstract
Despite tremendous progress in detecting DNA variants associated with human disease, interpreting their functional impact in a high-throughput and single-base resolution manner remains challenging. Here, we develop a pooled prime-editing screen method, PRIME, that can be applied to characterize thousands of coding and non-coding variants in a single experiment with high reproducibility. To showcase its applications, we first identified essential nucleotides for a 716 bp MYC enhancer via PRIME-mediated single-base resolution analysis. Next, we applied PRIME to functionally characterize 1,304 genome-wide association study (GWAS)-identified non-coding variants associated with breast cancer and 3,699 variants from ClinVar. We discovered that 103 non-coding variants and 156 variants of uncertain significance are functional via affecting cell fitness. Collectively, we demonstrate that PRIME is capable of characterizing genetic variants at single-base resolution and scale, advancing accurate genome annotation for disease risk prediction, diagnosis, and therapeutic target identification.
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Affiliation(s)
- Xingjie Ren
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, USA
| | - Han Yang
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, USA
| | - Jovia L Nierenberg
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA
| | - Yifan Sun
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, USA
| | - Jiawen Chen
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Cooper Beaman
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, USA
| | - Thu Pham
- Pharmaceutical Sciences and Pharmacogenomics Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Mai Nobuhara
- Pharmaceutical Sciences and Pharmacogenomics Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Maya Asami Takagi
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, USA
| | - Vivek Narayan
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, USA
| | - Yun Li
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Genetics, University of North Carolina, Chapel Hill, NC, USA; Department of Computer Science, University of North Carolina, Chapel Hill, NC, USA
| | - Elad Ziv
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, USA; Division of General Internal Medicine, Department of Medicine, and Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, USA
| | - Yin Shen
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA; Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA.
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4
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Orlic-Milacic M, Rothfels K, Matthews L, Wright A, Jassal B, Shamovsky V, Trinh Q, Gillespie M, Sevilla C, Tiwari K, Ragueneau E, Gong C, Stephan R, May B, Haw R, Weiser J, Beavers D, Conley P, Hermjakob H, Stein LD, D'Eustachio P, Wu G. Pathway-based, reaction-specific annotation of disease variants for elucidation of molecular phenotypes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.18.562964. [PMID: 37904913 PMCID: PMC10614924 DOI: 10.1101/2023.10.18.562964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2023]
Abstract
Disease variant annotation in the context of biological reactions and pathways can provide a standardized overview of molecular phenotypes of pathogenic mutations that is amenable to computational mining and mathematical modeling. Reactome, an open source, manually curated, peer-reviewed database of human biological pathways, provides annotations for over 4000 disease variants of close to 400 genes in the context of ∼800 disease reactions constituting ∼400 disease pathways. Functional annotation of disease variants proceeds from normal gene functions, through disease variants whose divergence from normal molecular behaviors has been experimentally verified, to extrapolation from molecular phenotypes of characterized variants to variants of unknown significance using criteria of the American College of Medical Genetics and Genomics (ACMG). Reactome's pathway-based, reaction-specific disease variant dataset and data model provide a platform to infer pathway output impacts of numerous human disease variants and model organism orthologs, complementing computational predictions of variant pathogenicity.
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5
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An J, Oh JH, Oh B, Oh YJ, Ju JS, Kim W, Kang HJ, Sung CO, Shim JH. Clinicogenomic characteristics and synthetic lethal implications of germline homologous recombination-deficient hepatocellular carcinoma. Hepatology 2023; 78:452-467. [PMID: 36177702 DOI: 10.1002/hep.32812] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 09/20/2022] [Accepted: 09/24/2022] [Indexed: 12/08/2022]
Abstract
BACKGROUNDS AND AIMS We performed an in-depth examination of pathogenic germline variants (PGVs) and somatic variants in DNA damage response (DDR) genes in hepatocellular carcinoma (HCC) to explore their clinical and genomic impacts. APPROACH AND RESULTS We used a merged whole-exome or RNA sequencing data set derived from in-house ( n = 230) and The Cancer Genome Atlas ( n = 362) databases of multiethnic HCC samples. We also evaluated synthetic lethal approaches targeting mutations in homologous recombination (HR) genes using HCC cells selected from five genomic databases of cancer cell lines. A total of 110 PGVs in DDR pathways in 96 patients were selected. Of the PGV carriers, 44 were HR-altered and found to be independently associated with poorer disease-free survival after hepatectomy. The most frequently altered HR gene in both germline and somatic tissues was POLQ , and this variant was detected in 22.7% (10/44) and 23.8% (5/21) of all the corresponding carriers, respectively. PGVs in HR were significantly associated with upregulation of proliferation and replication-related genes and familial risk of HCC. Samples harboring PGVs in HR with loss of heterozygosity were most strongly correlated with the genomic footprints of deficient HR, such as mutation burden and denovoSig2 (analogous to Catalogue of Somatic Mutations in Cancer [COSMIC] 3), and poor outcome. Pharmacologic experiments with HCC cells defective in BRCA2 or POLQ suggested that tumors with this phenotype are synthetic lethal with poly(ADP-ribose) polymerase inhibitors. CONCLUSIONS Our findings suggest that germline HR defects in HCC tend to confer a poor prognosis and result in distinctive genomic scarring. Tests of the clinical benefits of HR-directed treatments in the affected patients are needed.
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Affiliation(s)
- Jihyun An
- Gastroenterology and Hepatology , Hanyang University College of Medicine , Guri , Republic of Korea
| | - Ji-Hye Oh
- Medical Science, Asan Medical Institute of Convergence Science and Technology, University of Ulsan College of Medicine , Seoul , Republic of Korea
| | - Bora Oh
- Asan Institute for Life Science, Asan Medical Center , Seoul , Republic of Korea
| | - Yoo-Jin Oh
- Asan Institute for Life Science, Asan Medical Center , Seoul , Republic of Korea
| | - Jin-Sung Ju
- Asan Institute for Life Science, Asan Medical Center , Seoul , Republic of Korea
| | - Wonkyung Kim
- Medical Science, Asan Medical Institute of Convergence Science and Technology, University of Ulsan College of Medicine , Seoul , Republic of Korea
| | - Hyo Jung Kang
- Pathology, Asan Medical Center , University of Ulsan College of Medicine , Seoul , Republic of Korea
- Asan Liver Center, Asan Medical Center , University of Ulsan College of Medicine , Seoul , South Korea
| | - Chang Ohk Sung
- Medical Science, Asan Medical Institute of Convergence Science and Technology, University of Ulsan College of Medicine , Seoul , Republic of Korea
- Pathology, Asan Medical Center , University of Ulsan College of Medicine , Seoul , Republic of Korea
- Center for Cancer Genome Discovery , Asan Institute for Life Science, University of Ulsan College of Medicine, Asan Medical Center , Seoul , Republic of Korea
| | - Ju Hyun Shim
- Asan Liver Center, Asan Medical Center , University of Ulsan College of Medicine , Seoul , South Korea
- Gastroenterology, Asan Medical Center , University of Ulsan College of Medicine , Seoul , Republic of Korea
- Digestive Diseases Research Center , University of Ulsan College of Medicine , Seoul , Republic of Korea
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6
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Ren X, Yang H, Nierenberg JL, Sun Y, Chen J, Beaman C, Pham T, Nobuhara M, Takagi MA, Narayan V, Li Y, Ziv E, Shen Y. High throughput PRIME editing screens identify functional DNA variants in the human genome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.12.548736. [PMID: 37502948 PMCID: PMC10370011 DOI: 10.1101/2023.07.12.548736] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Despite tremendous progress in detecting DNA variants associated with human disease, interpreting their functional impact in a high-throughput and base-pair resolution manner remains challenging. Here, we develop a novel pooled prime editing screen method, PRIME, which can be applied to characterize thousands of coding and non-coding variants in a single experiment with high reproducibility. To showcase its applications, we first identified essential nucleotides for a 716 bp MYC enhancer via PRIME-mediated saturation mutagenesis. Next, we applied PRIME to functionally characterize 1,304 non-coding variants associated with breast cancer and 3,699 variants from ClinVar. We discovered that 103 non-coding variants and 156 variants of uncertain significance are functional via affecting cell fitness. Collectively, we demonstrate PRIME capable of characterizing genetic variants at base-pair resolution and scale, advancing accurate genome annotation for disease risk prediction, diagnosis, and therapeutic target identification.
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Affiliation(s)
- Xingjie Ren
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, USA
| | - Han Yang
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, USA
| | - Jovia L. Nierenberg
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA
| | - Yifan Sun
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, USA
| | - Jiawen Chen
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Cooper Beaman
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, USA
| | - Thu Pham
- Pharmaceutical Sciences and Pharmacogenomics Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Mai Nobuhara
- Pharmaceutical Sciences and Pharmacogenomics Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Maya Asami Takagi
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, USA
| | - Vivek Narayan
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, USA
| | - Yun Li
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Genetics, University of North Carolina, Chapel Hill, NC, USA
- Department of Computer Science, University of North Carolina, Chapel Hill, NC, USA
| | - Elad Ziv
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, USA
- Division of General Internal Medicine, Department of Medicine, and Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, USA
| | - Yin Shen
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
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Omole EB, Aijaz I, Ellegate J, Isenhart E, Desouki MM, Mastri M, Humphrey K, Dougherty EM, Rosario SR, Nastiuk KL, Ohm JE, Eng KH. Combined BRCA2 and MAGEC3 Expression Predict Outcome in Advanced Ovarian Cancers. Cancers (Basel) 2022; 14:cancers14194724. [PMID: 36230652 PMCID: PMC9562635 DOI: 10.3390/cancers14194724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 09/14/2022] [Accepted: 09/22/2022] [Indexed: 12/02/2022] Open
Abstract
Like BRCA2, MAGEC3 is an ovarian cancer predisposition gene that has been shown to have prognostic significance in ovarian cancer patients. Despite the clinical significance of each gene, no studies have been conducted to assess the clinical significance of their combined expression. We therefore sought to determine the relationship between MAGEC3 and BRCA2 expression in ovarian cancer and their association with patient characteristics and outcomes. Immunohistochemical staining was quantitated on tumor microarrays of human tumor samples obtained from 357 patients with epithelial ovarian cancer to ascertain BRCA2 expression levels. In conjunction with our previously published MAGEC3 expression data, we observed a weak inverse correlation of MAGEC3 with BRCA2 expression (r = −0.15; p < 0.05) in cases with full-length BRCA2. Patients with optimal cytoreduction, loss of MAGEC3, and detectable BRCA2 expression had better overall (median OS: 127.9 vs. 65.3 months, p = 0.035) and progression-free (median PFS: 85.3 vs. 18.8 months, p = 0.002) survival compared to patients that were BRCA2 expressors with MAGEC3 normal levels. Our results suggest that combined expression of MAGEC3 and BRCA2 serves as a better predictor of prognosis than each marker alone.
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Affiliation(s)
- Emmanuel B. Omole
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA
| | - Iqbal Aijaz
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA
| | - James Ellegate
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA
| | - Emily Isenhart
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA
- Department of Biostatistics and Bioinformatics, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA
| | - Mohamed M. Desouki
- Department of Pathology, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA
| | - Michalis Mastri
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA
| | - Kristen Humphrey
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA
| | - Emily M. Dougherty
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA
| | - Spencer R. Rosario
- Department of Biostatistics and Bioinformatics, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA
| | - Kent L. Nastiuk
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA
- Department of Urology, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA
| | - Joyce E. Ohm
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA
- Correspondence:
| | - Kevin H. Eng
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA
- Department of Biostatistics and Bioinformatics, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14263, USA
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8
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Jimenez-Sainz J, Mathew J, Moore G, Lahiri S, Garbarino J, Eder JP, Rothenberg E, Jensen RB. BRCA2 BRC missense variants disrupt RAD51-dependent DNA repair. eLife 2022; 11:e79183. [PMID: 36098506 PMCID: PMC9545528 DOI: 10.7554/elife.79183] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 09/12/2022] [Indexed: 11/24/2022] Open
Abstract
Pathogenic mutations in the BRCA2 tumor suppressor gene predispose to breast, ovarian, pancreatic, prostate, and other cancers. BRCA2 maintains genome stability through homology-directed repair (HDR) of DNA double-strand breaks (DSBs) and replication fork protection. Nonsense or frameshift mutations leading to truncation of the BRCA2 protein are typically considered pathogenic; however, missense mutations resulting in single amino acid substitutions can be challenging to functionally interpret. The majority of missense mutations in BRCA2 have been classified as Variants of Uncertain Significance (VUS) with unknown functional consequences. In this study, we identified three BRCA2 VUS located within the BRC repeat region to determine their impact on canonical HDR and fork protection functions. We provide evidence that S1221P and T1980I, which map to conserved residues in the BRC2 and BRC7 repeats, compromise the cellular response to chemotherapeutics and ionizing radiation, and display deficits in fork protection. We further demonstrate biochemically that S1221P and T1980I disrupt RAD51 binding and diminish the ability of BRCA2 to stabilize RAD51-ssDNA complexes. The third variant, T1346I, located within the spacer region between BRC2 and BRC3 repeats, is fully functional. We conclude that T1346I is a benign allele, whereas S1221P and T1980I are hypomorphic disrupting the ability of BRCA2 to fully engage and stabilize RAD51 nucleoprotein filaments. Our results underscore the importance of correctly classifying BRCA2 VUS as pathogenic variants can impact both future cancer risk and guide therapy selection during cancer treatment.
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Affiliation(s)
| | - Joshua Mathew
- Department of Therapeutic Radiology, Yale UniversityNew HavenUnited States
| | - Gemma Moore
- Department of Therapeutic Radiology, Yale UniversityNew HavenUnited States
| | - Sudipta Lahiri
- Department of Therapeutic Radiology, Yale UniversityNew HavenUnited States
| | - Jennifer Garbarino
- Department of Therapeutic Radiology, Yale UniversityNew HavenUnited States
| | - Joseph P Eder
- Department of Medical Oncology, Yale University School of Medicine, Yale Cancer CenterNew HavenUnited States
| | - Eli Rothenberg
- Department of Biochemistry and Molecular Pharmacology, New York UniversityNew YorkUnited States
| | - Ryan B Jensen
- Department of Therapeutic Radiology, Yale UniversityNew HavenUnited States
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9
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Long E, Patel H, Byun J, Amos CI, Choi J. Functional studies of lung cancer GWAS beyond association. Hum Mol Genet 2022; 31:R22-R36. [PMID: 35776125 DOI: 10.1093/hmg/ddac140] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/01/2022] [Accepted: 06/16/2022] [Indexed: 11/14/2022] Open
Abstract
Fourteen years after the first genome-wide association study (GWAS) of lung cancer was published, approximately forty-five genomic loci have now been significantly associated with lung cancer risk. While functional characterization was performed for several of these loci, a comprehensive summary of current molecular understanding of lung cancer risk has been lacking. Further, many novel computational and experimental tools now became available to accelerate the functional assessment of disease-associated variants, moving beyond locus-by-locus approaches. In this review, we first highlight the heterogeneity of lung cancer GWAS findings across histological subtypes, ancestries, and smoking status, which poses unique challenges to follow-up studies. We then summarize the published lung cancer post-GWAS studies for each risk-associated locus to assess the current understanding of biological mechanisms beyond the initial statistical association. We further summarize strategies for GWAS functional follow-up studies considering cutting-edge functional genomics tools and providing a catalog of available resources relevant to lung cancer. Overall, we aim to highlight the importance of integrating computational and experimental approaches to draw biological insights from the lung cancer GWAS results beyond association.
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Affiliation(s)
- Erping Long
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Harsh Patel
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jinyoung Byun
- Institute for Clinical and Translational Research, Baylor College of Medicine, Houston, TX, 77030, USA.,Section of Epidemiology and Population Sciences, Department of Medicine, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Christopher I Amos
- Institute for Clinical and Translational Research, Baylor College of Medicine, Houston, TX, 77030, USA.,Section of Epidemiology and Population Sciences, Department of Medicine, Baylor College of Medicine, Houston, TX, 77030, USA.,Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Jiyeon Choi
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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10
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Jimenez-Sainz J, Krysztofiak A, Garbarino J, Rogers F, Jensen RB. The Pathogenic R3052W BRCA2 Variant Disrupts Homology-Directed Repair by Failing to Localize to the Nucleus. Front Genet 2022; 13:884210. [PMID: 35711920 PMCID: PMC9197106 DOI: 10.3389/fgene.2022.884210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 04/22/2022] [Indexed: 12/04/2022] Open
Abstract
The BRCA2 germline missense variant, R3052W, resides in the DNA binding domain and has been previously classified as a pathogenic allele. In this study, we sought to determine how R3052W alters the cellular functions of BRCA2 in the DNA damage response. The BRCA2 R3052W mutated protein exacerbates genome instability, is unable to rescue homology-directed repair, and fails to complement cell survival following exposure to PARP inhibitors and crosslinking drugs. Surprisingly, despite anticipated defects in DNA binding or RAD51-mediated DNA strand exchange, the BRCA2 R3052W protein mislocalizes to the cytoplasm precluding its ability to perform any DNA repair functions. Rather than acting as a simple loss-of-function mutation, R3052W behaves as a dominant negative allele, likely by sequestering RAD51 in the cytoplasm.
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Affiliation(s)
| | | | | | | | - Ryan B. Jensen
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, United States
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11
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Assessing the Variations in Breast/Ovarian Cancer Risk for Chinese BRCA1/2 Carriers. JOURNAL OF ONCOLOGY 2022; 2022:9390539. [PMID: 35378767 PMCID: PMC8976609 DOI: 10.1155/2022/9390539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Accepted: 02/28/2022] [Indexed: 11/17/2022]
Abstract
Background. Cancer risks vary in different BRCA1/2 mutations. We are interested in identifying regions associated with elevated/reduced risks of breast/ovarian cancers in the Chinese population and comparing with previously reported Caucasian-based breast/ovarian cancer cluster regions (OCCR/BCCR). We also aim to characterize the distribution and estimate the cancer risks of different Chinese recurrent mutations. Methods. A total of 3,641 cancer-free women and 4,278 female cancer patients were included in the study. Germline BRCA1/2 status was detected with amplicon-based next-generation sequencing. We calculated the odds ratio (OR) of breast cancer and OR of ovarian cancer, and their ratio of the two ORs (ROR) for each region. ROR >1 indicated elevated odds of breast cancer and/or decreasing odds of ovarian cancer, and vice versa. The frequency, distribution, and penetrance of six known Chinese founder mutations were characterized, respectively. Haplotype analysis and age estimation were performed on the most prevalent founder mutation BRCA1: c.5470_5477del. Results. A total of 729 subjects were detected with germline BRCA1/2 deleterious mutations. The putative Chinese OCCR/BCCR partially overlapped with Caucasian-based OCCR/BCCR and shared structural-functional characteristics. The six known Chinese founder mutations greatly vary in both distribution and penetrance. The two widely spread mutations are estimated to convey low penetrance, while the area-restricted founder mutations seemed to confer higher/complete penetrance. BRCA1: c.5470_5477del is estimated to have emerged ∼2,090 years ago (70 B.C.) during the Han dynasty. Conclusions. BRCA1/2 carriers with different genotypes have significantly different cancer risks. An optimal risk assessment should be mutation specific, rather than concerning a single figure.
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12
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McFarland TR, Tandar CE, Agarwal N, Swami U. Emergence of polyclonal BRCA2 reversions following PARP inhibitor treatment: An illustrative case report. Cancer Treat Res Commun 2021; 29:100480. [PMID: 34700141 DOI: 10.1016/j.ctarc.2021.100480] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 10/14/2021] [Indexed: 11/26/2022]
Abstract
Cancers with mutations in BRCA2 have defective DNA repair capacity which is potentially targetable with poly-ADP(ribose) polymera se (PARP) inhibitors such as olaparib and rucaparib. However, the development of a secondary mutation that restores BRCA2 function is a well-documented mechanism of resistance to PARP inhibitors. Here, we present a case report of a man with metastatic castration-resistant prostate cancer with a germline BRCA2 frameshift mutation. Treatment with olaparib resulted in an initial response but was followed by progression. Cell-free DNA testing after progression revealed the presence of polyclonal BRCA2 mutations that were estimated to restore it into the correct reading frame. We describe his treatment course and genetic testing results and then discuss the biological mechanisms driving this mechanism of resistance.
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Affiliation(s)
- Taylor Ryan McFarland
- Division of Oncology, Department of Internal Medicine, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, United States
| | - Clara Elizabeth Tandar
- Division of Oncology, Department of Internal Medicine, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, United States
| | - Neeraj Agarwal
- Division of Oncology, Department of Internal Medicine, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, United States.
| | - Umang Swami
- Division of Oncology, Department of Internal Medicine, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, United States.
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13
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Kang Z, Fu P, Alcivar AL, Fu H, Redon C, Foo TK, Zuo Y, Ye C, Baxley R, Madireddy A, Buisson R, Bielinsky AK, Zou L, Shen Z, Aladjem MI, Xia B. BRCA2 associates with MCM10 to suppress PRIMPOL-mediated repriming and single-stranded gap formation after DNA damage. Nat Commun 2021; 12:5966. [PMID: 34645815 PMCID: PMC8514439 DOI: 10.1038/s41467-021-26227-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 09/23/2021] [Indexed: 11/28/2022] Open
Abstract
The BRCA2 tumor suppressor protects genome integrity by promoting homologous recombination-based repair of DNA breaks, stability of stalled DNA replication forks and DNA damage-induced cell cycle checkpoints. BRCA2 deficient cells display the radio-resistant DNA synthesis (RDS) phenotype, however the mechanism has remained elusive. Here we show that cells without BRCA2 are unable to sufficiently restrain DNA replication fork progression after DNA damage, and the underrestrained fork progression is due primarily to Primase-Polymerase (PRIMPOL)-mediated repriming of DNA synthesis downstream of lesions, leaving behind single-stranded DNA gaps. Moreover, we find that BRCA2 associates with the essential DNA replication factor MCM10 and this association suppresses PRIMPOL-mediated repriming and ssDNA gap formation, while having no impact on the stability of stalled replication forks. Our findings establish an important function for BRCA2, provide insights into replication fork control during the DNA damage response, and may have implications in tumor suppression and therapy response. Tumor suppressor BRCA2 is known to stabilize and restart stalled DNA replication forks. Here the authors show that BRCA2 is recruited to the replication fork through its interaction with MCM10 and inhibits Primase-Polymerase-mediated repriming, lesion bypass and single strand DNA gap formation after DNA damage.
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Affiliation(s)
- Zhihua Kang
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA
| | - Pan Fu
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA.,Department of Clinical Microbiology Laboratory, Children's Hospital of Fudan University, Shanghai, China
| | - Allen L Alcivar
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA.,Bristol-Myers Squibb Company, Bloomsbury, NJ, 08804, USA
| | - Haiqing Fu
- Developmental Therapeutics Group, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Christophe Redon
- Developmental Therapeutics Group, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Tzeh Keong Foo
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA
| | - Yamei Zuo
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA
| | - Caiyong Ye
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA.,School of Radiation Medicine and Protection, Soochow University, Suzhou, China
| | - Ryan Baxley
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Advaitha Madireddy
- Department of Pediatric Hematology/Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA
| | - Remi Buisson
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, MA, USA.,Department of Biological Chemistry, University of California Irvine, Irvine, CA, USA
| | - Anja-Katrin Bielinsky
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Lee Zou
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, MA, USA
| | - Zhiyuan Shen
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA
| | - Mirit I Aladjem
- Developmental Therapeutics Group, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Bing Xia
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA.
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14
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Paul MW, Sidhu A, Liang Y, van Rossum-Fikkert SE, Odijk H, Zelensky AN, Kanaar R, Wyman C. Role of BRCA2 DNA-binding and C-terminal domain in its mobility and conformation in DNA repair. eLife 2021; 10:e67926. [PMID: 34254584 PMCID: PMC8324294 DOI: 10.7554/elife.67926] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 07/12/2021] [Indexed: 11/30/2022] Open
Abstract
Breast cancer type two susceptibility protein (BRCA2) is an essential protein in genome maintenance, homologous recombination (HR), and replication fork protection. Its function includes multiple interaction partners and requires timely localization to relevant sites in the nucleus. We investigated the importance of the highly conserved DNA-binding domain (DBD) and C-terminal domain (CTD) of BRCA2. We generated BRCA2 variants missing one or both domains in mouse embryonic stem (ES) cells and defined their contribution in HR function and dynamic localization in the nucleus, by single-particle tracking of BRCA2 mobility. Changes in molecular architecture of BRCA2 induced by binding partners of purified BRCA2 were determined by scanning force microscopy. BRCA2 mobility and DNA-damage-induced increase in the immobile fraction were largely unaffected by C-terminal deletions. The purified proteins missing CTD and/or DBD were defective in architectural changes correlating with reduced HR function in cells. These results emphasize BRCA2 activity at sites of damage beyond promoting RAD51 delivery.
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Affiliation(s)
- Maarten W Paul
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical CenterRotterdamNetherlands
| | - Arshdeep Sidhu
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical CenterRotterdamNetherlands
- Department of Radiation Oncology, Erasmus University Medical CenterRotterdamNetherlands
| | - Yongxin Liang
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical CenterRotterdamNetherlands
| | - Sarah E van Rossum-Fikkert
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical CenterRotterdamNetherlands
- Department of Radiation Oncology, Erasmus University Medical CenterRotterdamNetherlands
| | - Hanny Odijk
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical CenterRotterdamNetherlands
| | - Alex N Zelensky
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical CenterRotterdamNetherlands
| | - Roland Kanaar
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical CenterRotterdamNetherlands
| | - Claire Wyman
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical CenterRotterdamNetherlands
- Department of Radiation Oncology, Erasmus University Medical CenterRotterdamNetherlands
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15
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The Genetic Analyses of French Canadians of Quebec Facilitate the Characterization of New Cancer Predisposing Genes Implicated in Hereditary Breast and/or Ovarian Cancer Syndrome Families. Cancers (Basel) 2021; 13:cancers13143406. [PMID: 34298626 PMCID: PMC8305212 DOI: 10.3390/cancers13143406] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 12/19/2022] Open
Abstract
The French Canadian population of the province of Quebec has been recognized for its contribution to research in medical genetics, especially in defining the role of heritable pathogenic variants in cancer predisposing genes. Multiple carriers of a limited number of pathogenic variants in BRCA1 and BRCA2, the major risk genes for hereditary breast and/or ovarian cancer syndrome families, have been identified in French Canadians, which is in stark contrast to the array of over 2000 different pathogenic variants reported in each of these genes in other populations. As not all such cancer syndrome families are explained by BRCA1 and BRCA2, newly proposed gene candidates identified in other populations have been investigated for their role in conferring risk in French Canadian cancer families. For example, multiple carriers of distinct variants were identified in PALB2 and RAD51D. The unique genetic architecture of French Canadians has been attributed to shared ancestry due to common ancestors of early settlers of this population with origins mainly from France. In this review, we discuss the merits of genetically characterizing cancer predisposing genes in French Canadians of Quebec. We focused on genes that have been implicated in hereditary breast and/or ovarian cancer syndrome families as they have been the most thoroughly characterized cancer syndromes in this population. We describe how genetic analyses of French Canadians have facilitated: (i) the classification of variants in BRCA1 and BRCA2; (ii) the identification and classification of variants in newly proposed breast and/or ovarian cancer predisposing genes; and (iii) the identification of a new breast cancer predisposing gene candidate, RECQL. The genetic architecture of French Canadians provides a unique opportunity to evaluate new candidate cancer predisposing genes regardless of the population in which they were identified.
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16
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Lee M, Shorthouse D, Mahen R, Hall BA, Venkitaraman AR. Cancer-causing BRCA2 missense mutations disrupt an intracellular protein assembly mechanism to disable genome maintenance. Nucleic Acids Res 2021; 49:5588-5604. [PMID: 33978741 PMCID: PMC8191791 DOI: 10.1093/nar/gkab308] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 04/11/2021] [Accepted: 04/28/2021] [Indexed: 12/13/2022] Open
Abstract
Cancer-causing missense mutations in the 3418 amino acid BRCA2 breast and ovarian cancer suppressor protein frequently affect a short (∼340 residue) segment in its carboxyl-terminal domain (DBD). Here, we identify a shared molecular mechanism underlying their pathogenicity. Pathogenic BRCA2 missense mutations cluster in the DBD’s helical domain (HD) and OB1-fold motifs, which engage the partner protein DSS1. Pathogenic - but not benign – DBD mutations weaken or abolish DSS1-BRCA2 assembly, provoking mutant BRCA2 oligomers that are excluded from the cell nucleus, and disable DNA repair by homologous DNA recombination (HDR). DSS1 inhibits the intracellular oligomerization of wildtype, but not mutant, forms of BRCA2. Remarkably, DSS1 expression corrects defective HDR in cells bearing pathogenic BRCA2 missense mutants with weakened, but not absent, DSS1 binding. Our findings identify a DSS1-mediated intracellular protein assembly mechanism that is disrupted by cancer-causing BRCA2 missense mutations, and suggest an approach for its therapeutic correction.
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Affiliation(s)
- Miyoung Lee
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
| | - David Shorthouse
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
| | - Robert Mahen
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
| | - Benjamin A Hall
- 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.,The Cancer Science Institute of Singapore, National University of Singapore, 14 Medical Drive, Singapore 117599 & Agency for Science, Technology and Research (A*STAR), 8A Biomedical Grove 138648, Singapore
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17
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Andreassen PR, Seo J, Wiek C, Hanenberg H. Understanding BRCA2 Function as a Tumor Suppressor Based on Domain-Specific Activities in DNA Damage Responses. Genes (Basel) 2021; 12:genes12071034. [PMID: 34356050 PMCID: PMC8307705 DOI: 10.3390/genes12071034] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/23/2021] [Accepted: 06/29/2021] [Indexed: 01/14/2023] Open
Abstract
BRCA2 is an essential genome stability gene that has various functions in cells, including roles in homologous recombination, G2 checkpoint control, protection of stalled replication forks, and promotion of cellular resistance to numerous types of DNA damage. Heterozygous mutation of BRCA2 is associated with an increased risk of developing cancers of the breast, ovaries, pancreas, and other sites, thus BRCA2 acts as a classic tumor suppressor gene. However, understanding BRCA2 function as a tumor suppressor is severely limited by the fact that ~70% of the encoded protein has not been tested or assigned a function in the cellular DNA damage response. Remarkably, even the specific role(s) of many known domains in BRCA2 are not well characterized, predominantly because stable expression of the very large BRCA2 protein in cells, for experimental purposes, is challenging. Here, we review what is known about these domains and the assay systems that are available to study the cellular roles of BRCA2 domains in DNA damage responses. We also list criteria for better testing systems because, ultimately, functional assays for assessing the impact of germline and acquired mutations identified in genetic screens are important for guiding cancer prevention measures and for tailored cancer treatments.
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Affiliation(s)
- Paul R. Andreassen
- Division of Experimental Hematology and Cancer Biology, Cancer and Blood Diseases Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA;
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
- Correspondence: ; Tel.: +1-(513)-636-0499
| | - Joonbae Seo
- Division of Experimental Hematology and Cancer Biology, Cancer and Blood Diseases Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA;
| | - Constanze Wiek
- Department of Otorhinolaryngology and Head/Neck Surgery, Heinrich Heine University, 40225 Düsseldorf, Germany; (C.W.); (H.H.)
| | - Helmut Hanenberg
- Department of Otorhinolaryngology and Head/Neck Surgery, Heinrich Heine University, 40225 Düsseldorf, Germany; (C.W.); (H.H.)
- Department of Pediatrics III, Children’s Hospital, University of Duisburg-Essen, 45122 Essen, Germany
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18
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Jimenez-Sainz J, Jensen RB. Imprecise Medicine: BRCA2 Variants of Uncertain Significance (VUS), the Challenges and Benefits to Integrate a Functional Assay Workflow with Clinical Decision Rules. Genes (Basel) 2021; 12:genes12050780. [PMID: 34065235 PMCID: PMC8161351 DOI: 10.3390/genes12050780] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/14/2021] [Accepted: 05/18/2021] [Indexed: 12/20/2022] Open
Abstract
Pathological mutations in homology-directed repair (HDR) genes impact both future cancer risk and therapeutic options for patients. HDR is a high-fidelity DNA repair pathway for resolving DNA double-strand breaks throughout the genome. BRCA2 is an essential protein that mediates the loading of RAD51 onto resected DNA breaks, a key step in HDR. Germline mutations in BRCA2 are associated with an increased risk for breast, ovarian, prostate, and pancreatic cancer. Clinical findings of germline or somatic BRCA2 mutations in tumors suggest treatment with platinum agents or PARP inhibitors. However, when genetic analysis reveals a variant of uncertain significance (VUS) in the BRCA2 gene, precision medicine-based decisions become complex. VUS are genetic changes with unknown pathological impact. Current statistics indicate that between 10–20% of BRCA sequencing results are VUS, and of these, more than 50% are missense mutations. Functional assays to determine the pathological outcome of VUS are urgently needed to provide clinical guidance regarding cancer risk and treatment options. In this review, we provide a brief overview of BRCA2 functions in HDR, describe how BRCA2 VUS are currently assessed in the clinic, and how genetic and biochemical functional assays could be integrated into the clinical decision process. We suggest a multi-step workflow composed of robust and accurate functional assays to correctly evaluate the potential pathogenic or benign nature of BRCA2 VUS. Success in this precision medicine endeavor will offer actionable information to patients and their physicians.
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Affiliation(s)
- Judit Jimenez-Sainz
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
- Correspondence: (J.J.-S.); (R.B.J.); Tel.:+1-203-737-6456 (R.B.J.)
| | - Ryan B. Jensen
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Pathology, Yale University School of Medicine, New Haven, CT 06520, USA
- Correspondence: (J.J.-S.); (R.B.J.); Tel.:+1-203-737-6456 (R.B.J.)
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19
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K3326X and Other C-Terminal BRCA2 Variants Implicated in Hereditary Cancer Syndromes: A Review. Cancers (Basel) 2021; 13:cancers13030447. [PMID: 33503928 PMCID: PMC7865497 DOI: 10.3390/cancers13030447] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 01/11/2021] [Accepted: 01/21/2021] [Indexed: 02/06/2023] Open
Abstract
Simple Summary The cancer associated protein BRCA2 is the subject of intense continual study. Because of this, new insights into the relation of specific variants of this gene and cancer are regularly generated. These discoveries shed light on cancer risk and management for patients carrying these mutations. Additionally, new techniques for variant discovery and investigation are developed and tested, further enhancing scientific and clinical understanding of this key protein. In this review we will investigate the recent literature associated with variants in the C-terminus of BRCA2 and their effect on health and cancer predisposition. Abstract Whole genome analysis and the search for mutations in germline and tumor DNAs is becoming a major tool in the evaluation of risk as well as the management of hereditary cancer syndromes. Because of the identification of cancer predisposition gene panels, thousands of such variants have been catalogued yet many remain unclassified, presenting a clinical challenge for the management of hereditary cancer syndromes. Although algorithms exist to estimate the likelihood of a variant being deleterious, these tools are rarely used for clinical decision-making. Here, we review the progress in classifying K3326X, a rare truncating variant on the C-terminus of BRCA2 and review recent literature on other novel single nucleotide polymorphisms, SNPs, on the C-terminus of the protein, defined in this review as the portion after the final BRC repeat (amino acids 2058–3418).
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20
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Ehlén Å, Martin C, Miron S, Julien M, Theillet FX, Ropars V, Sessa G, Beaurepere R, Boucherit V, Duchambon P, El Marjou A, Zinn-Justin S, Carreira A. Proper chromosome alignment depends on BRCA2 phosphorylation by PLK1. Nat Commun 2020; 11:1819. [PMID: 32286328 PMCID: PMC7156385 DOI: 10.1038/s41467-020-15689-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 03/20/2020] [Indexed: 12/18/2022] Open
Abstract
The BRCA2 tumor suppressor protein is involved in the maintenance of genome integrity through its role in homologous recombination. In mitosis, BRCA2 is phosphorylated by Polo-like kinase 1 (PLK1). Here we describe how this phosphorylation contributes to the control of mitosis. We identify a conserved phosphorylation site at T207 of BRCA2 that constitutes a bona fide docking site for PLK1 and is phosphorylated in mitotic cells. We show that BRCA2 bound to PLK1 forms a complex with the phosphatase PP2A and phosphorylated-BUBR1. Reducing BRCA2 binding to PLK1, as observed in BRCA2 breast cancer variants S206C and T207A, alters the tetrameric complex resulting in unstable kinetochore-microtubule interactions, misaligned chromosomes, faulty chromosome segregation and aneuploidy. We thus reveal a role of BRCA2 in the alignment of chromosomes, distinct from its DNA repair function, with important consequences on chromosome stability. These findings may explain in part the aneuploidy observed in BRCA2-mutated tumors.
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Affiliation(s)
- Åsa Ehlén
- Institut Curie, PSL Research University, CNRS, UMR3348, F-91405, Orsay, France
- Paris Sud University, Paris-Saclay University CNRS, UMR3348, F-91405, Orsay, France
| | - Charlotte Martin
- Institut Curie, PSL Research University, CNRS, UMR3348, F-91405, Orsay, France
- Paris Sud University, Paris-Saclay University CNRS, UMR3348, F-91405, Orsay, France
| | - Simona Miron
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, Cedex, France
| | - Manon Julien
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, Cedex, France
- Department of Biology, École Normale Supérieure, 94230, Cachan, France
| | - François-Xavier Theillet
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, Cedex, France
| | - Virginie Ropars
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, Cedex, France
| | - Gaetana Sessa
- Institut Curie, PSL Research University, CNRS, UMR3348, F-91405, Orsay, France
- Paris Sud University, Paris-Saclay University CNRS, UMR3348, F-91405, Orsay, France
| | - Romane Beaurepere
- Institut Curie, PSL Research University, CNRS, UMR3348, F-91405, Orsay, France
- Paris Sud University, Paris-Saclay University CNRS, UMR3348, F-91405, Orsay, France
| | - Virginie Boucherit
- Institut Curie, PSL Research University, CNRS, UMR3348, F-91405, Orsay, France
- Paris Sud University, Paris-Saclay University CNRS, UMR3348, F-91405, Orsay, France
| | - Patricia Duchambon
- Protein Expression and Purification Core Facility, Institut Curie, 26 rue d'Ulm, 75248, Paris, Cedex 05, France
- INSERM U1196, 91405, Orsay, Cedex, France
| | - Ahmed El Marjou
- Protein Expression and Purification Core Facility, Institut Curie, 26 rue d'Ulm, 75248, Paris, Cedex 05, France
- CNRS UMR144, 12 rue Lhomond, 75005, Paris, France
| | - Sophie Zinn-Justin
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, Cedex, France.
| | - Aura Carreira
- Institut Curie, PSL Research University, CNRS, UMR3348, F-91405, Orsay, France.
- Paris Sud University, Paris-Saclay University CNRS, UMR3348, F-91405, Orsay, France.
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21
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Thumser-Henner P, Nytko KJ, Rohrer Bley C. Mutations of BRCA2 in canine mammary tumors and their targeting potential in clinical therapy. BMC Vet Res 2020; 16:30. [PMID: 32005245 PMCID: PMC6995156 DOI: 10.1186/s12917-020-2247-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 01/17/2020] [Indexed: 02/08/2023] Open
Abstract
Dogs develop cancer spontaneously with age, with breed-specific risk underlying differences in genetics. Mammary tumors are reported as the most frequent neoplasia in intact female dogs. Their high prevalence in certain breeds suggests a genetic component, as it is the case in human familial breast cancer, distinctly in BRCA2-associated cancers. However, the molecular genetics of BRCA2 in the pathogenesis of canine cancer are still under investigation.Genetic variations of canine BRCA2 comprised single nucleotide polymorphisms, insertions and deletions. The BRCA2 level has been shown to be reduced in tumor gland samples, suggesting that low expression of BRCA2 is contributing to mammary tumor development in dogs. Additionally, specific variations of the BRCA2 gene affect RAD51 binding strength, critically damage the BRCA2-RAD51 binding and further provoke a defective repair. In humans, preclinical and clinical data revealed a synthetic lethality interaction between BRCA2 mutations and PARP inhibition. PARP inhibitors are successfully used to increase chemo- and radiotherapy sensitivity, although they are also associated with numerous side effects and acquired resistance. Cancer treatment of canine patients could benefit from increased chemo- and radiosensitivity, as their cancer therapy protocols usually include only low doses of drugs or radiation. Early investigations show tolerability of iniparib in dogs. PARP inhibitors also imply higher therapy costs and consequently are less likely to be accepted by pet owners.We summarized the current evidence of canine BRCA2 gene alterations and their association with mammary tumors. Mutations in the canine BRCA2 gene have the potential to be exploited in clinical therapy through the usage of PARP inhibitors. However, further investigations are needed before introducing PARP inhibitors in veterinary clinical practice.
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Affiliation(s)
- Pauline Thumser-Henner
- Division of Radiation Oncology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
| | - Katarzyna J Nytko
- Division of Radiation Oncology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Carla Rohrer Bley
- Division of Radiation Oncology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
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22
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Ko JMY, Ning L, Zhao XK, Chai AWY, Lei LC, Choi SSA, Tao L, Law S, Kwong A, Lee NPY, Chan KT, Lo A, Song X, Chen PN, Chang YL, Wang LD, Lung ML. BRCA2 loss-of-function germline mutations are associated with esophageal squamous cell carcinoma risk in Chinese. Int J Cancer 2019; 146:1042-1051. [PMID: 31396961 DOI: 10.1002/ijc.32619] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 07/05/2019] [Accepted: 07/24/2019] [Indexed: 12/23/2022]
Abstract
Esophageal squamous cell carcinoma (ESCC) occurs with highest frequency in China with over 90% mortality, highlighting the need for early detection and improved treatment strategies. We aimed to identify ESCC cancer predisposition gene(s). Our study included 4,517 individuals. The discovery phase using whole-exome sequencing (WES) included 186 familial ESCC patients from high-risk China. Targeted gene sequencing validation of 598 genes included 3,289 Henan and 1,228 moderate-risk Hong Kong Chinese. A WES approach identified BRCA2 loss-of-function (LOF) mutations in 3.23% (6/186) familial ESCC patients compared to 0.21% (9/4300) in the ExAC East Asians (odds ratio [OR] = 15.89, p = 2.48 × 10-10 ). BRCA2 LOF mutation frequency in the combined Henan cohort has significantly higher prevalence (OR = 10.55, p = 0.0035). Results were independently validated in an ESCC Hong Kong cohort (OR = 10.64, p = 0.022). One Hong Kong pedigree was identified to carry a BRCA2 LOF mutation. BRCA2 inactivation in ESCC was via germline LOF mutations and wild-type somatic allelic loss via loss of heterozygosity. Gene-based association analysis, including LOF mutations and rare deleterious missense variants defined with combined annotation dependent depletion score ≥30, confirmed the genetic predisposition role of BRCA2 (OR = 9.50, p = 3.44 × 10-5 ), and provided new evidence for potential association of ESCC risk with DNA repair genes (POLQ and MSH2), inflammation (TTC39B) and angiogenesis (KDR). Our findings are the first to provide compelling evidence of the role of BRCA2 in ESCC genetic susceptibility in Chinese, suggesting defective homologous recombination is an underlying cause in ESCC pathogenesis, which is amenable to therapeutic options based on synthetic lethality approaches such as targeting BRCA2 with PARP1 inhibitors in ESCC.
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Affiliation(s)
- Josephine Mun-Yee Ko
- Department of Clinical Oncology, University of Hong Kong, Hong Kong, People's Republic of China
| | - Lvwen Ning
- Department of Clinical Oncology, University of Hong Kong, Hong Kong, People's Republic of China
| | - Xue-Ke Zhao
- Henan Key Laboratory for Esophageal Cancer Research of the First Affiliated Hospital, State Key Laboratory for Esophageal Cancer Prevention & Treatment, Zhengzhou University, Zhengzhou, Henan, People's Republic of China
| | - Annie Wai Yeeng Chai
- Department of Clinical Oncology, University of Hong Kong, Hong Kong, People's Republic of China
| | - Lisa Chan Lei
- Department of Clinical Oncology, University of Hong Kong, Hong Kong, People's Republic of China
| | - Sheyne Sta Ana Choi
- Department of Clinical Oncology, University of Hong Kong, Hong Kong, People's Republic of China
| | - Lihua Tao
- Department of Clinical Oncology, University of Hong Kong, Hong Kong, People's Republic of China
| | - Simon Law
- Department of Surgery, University of Hong Kong, Hong Kong, People's Republic of China
| | - Ava Kwong
- Department of Surgery, University of Hong Kong, Hong Kong, People's Republic of China.,Hereditary Breast Cancer Family Registry Cancer Genetics Center, Hong Kong Sanatorium and Hospital, Hong Kong, People's Republic of China
| | - Nikki Pui-Yue Lee
- Department of Surgery, University of Hong Kong, Hong Kong, People's Republic of China
| | - Kin-Tak Chan
- Department of Surgery, University of Hong Kong, Hong Kong, People's Republic of China
| | - Anthony Lo
- Division of Anatomical Pathology, Queen Mary Hospital, Hong Kong, People's Republic of China
| | - Xin Song
- Henan Key Laboratory for Esophageal Cancer Research of the First Affiliated Hospital, State Key Laboratory for Esophageal Cancer Prevention & Treatment, Zhengzhou University, Zhengzhou, Henan, People's Republic of China
| | - Pei-Nan Chen
- Henan Key Laboratory for Esophageal Cancer Research of the First Affiliated Hospital, State Key Laboratory for Esophageal Cancer Prevention & Treatment, Zhengzhou University, Zhengzhou, Henan, People's Republic of China
| | - Yun-Li Chang
- Department of Gastroenterology, Shanghai University of Medicine and Health Sciences, Affiliated Zhoupu Hospital, Shanghai, People's Republic of China
| | - Li Dong Wang
- Henan Key Laboratory for Esophageal Cancer Research of the First Affiliated Hospital, State Key Laboratory for Esophageal Cancer Prevention & Treatment, Zhengzhou University, Zhengzhou, Henan, People's Republic of China
| | - Maria Li Lung
- Department of Clinical Oncology, University of Hong Kong, Hong Kong, People's Republic of China
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24
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Pathania S, Garber JE. Mixing Mutation Location With Carcinogen Exposure: A Recipe for Tissue Specificity in BRCA2-Associated Cancers? J Natl Cancer Inst 2018; 110:925-926. [PMID: 29767746 DOI: 10.1093/jnci/djy047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 03/02/2018] [Indexed: 11/15/2022] Open
Affiliation(s)
- Shailja Pathania
- Center for Personalized Cancer Therapy, Department of Biology, University of Massachusetts Boston, Boston, MA
| | - Judy E Garber
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
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25
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Browning CL, Wise JP. Prolonged exposure to particulate chromate inhibits RAD51 nuclear import mediator proteins. Toxicol Appl Pharmacol 2017; 331:101-107. [PMID: 28554658 PMCID: PMC5568470 DOI: 10.1016/j.taap.2017.05.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/19/2017] [Accepted: 05/24/2017] [Indexed: 12/21/2022]
Abstract
Particulate hexavalent chromium (Cr(VI)) is a human lung carcinogen and a human health concern. The induction of structural chromosome instability is considered to be a driving mechanism of Cr(VI)-induced carcinogenesis. Homologous recombination repair protects against Cr(VI)-induced chromosome damage, due to its highly accurate repair of Cr(VI)-induced DNA double strand breaks. However, recent studies demonstrate Cr(VI) inhibits homologous recombination repair through the misregulation of RAD51. RAD51 is an essential protein in HR repair that facilitates the search for a homologous sequence. Recent studies show prolonged Cr(VI) exposure prevents proper RAD51 subcellular localization, causing it to accumulate in the cytoplasm. Since nuclear import of RAD51 is crucial to its function, this study investigated the effect of Cr(VI) on the RAD51 nuclear import mediators, RAD51C and BRCA2. We show acute (24h) Cr(VI) exposure induces the proper localization of RAD51C and BRCA2. In contrast, prolonged (120h) exposure increased the cytoplasmic localization of both proteins, although RAD51C localization was more severely impaired. These results correlate temporally with the previously reported Cr(VI)-induced RAD51 cytoplasmic accumulation. In addition, we found Cr(VI) does not inhibit interaction between RAD51 and its nuclear import mediators. Altogether, our results suggest prolonged Cr(VI) exposure inhibits the nuclear import of RAD51C, and to a lesser extent, BRCA2, which results in the cytoplasmic accumulation of RAD51. Cr(VI)-induced inhibition of nuclear import may play a key role in its carcinogenic mechanism since the nuclear import of many tumor suppressor proteins and DNA repair proteins is crucial to their function.
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Affiliation(s)
- Cynthia L Browning
- Wise Laboratory of Environmental and Genetic Toxicology, Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY 40292, United States; Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469, United States.
| | - John Pierce Wise
- Wise Laboratory of Environmental and Genetic Toxicology, Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY 40292, United States; Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469, United States.
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26
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Klimov S, Rida PC, Aleskandarany MA, Green AR, Ellis IO, Janssen EA, Rakha EA, Aneja R. Novel immunohistochemistry-based signatures to predict metastatic site of triple-negative breast cancers. Br J Cancer 2017; 117:826-834. [PMID: 28720841 PMCID: PMC5589983 DOI: 10.1038/bjc.2017.224] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 05/23/2017] [Accepted: 06/21/2017] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Although distant metastasis (DM) in breast cancer (BC) is the most lethal form of recurrence and the most common underlying cause of cancer related deaths, the outcome following the development of DM is related to the site of metastasis. Triple negative BC (TNBC) is an aggressive form of BC characterised by early recurrences and high mortality. Athough multiple variables can be used to predict the risk of metastasis, few markers can predict the specific site of metastasis. This study aimed at identifying a biomarker signature to predict particular sites of DM in TNBC. METHODS A clinically annotated series of 322 TNBC were immunohistochemically stained with 133 biomarkers relevant to BC, to develop multibiomarker models for predicting metastasis to the bone, liver, lung and brain. Patients who experienced metastasis to each site were compared with those who did not, by gradually filtering the biomarker set via a two-tailed t-test and Cox univariate analyses. Biomarker combinations were finally ranked based on statistical significance, and evaluated in multivariable analyses. RESULTS Our final models were able to stratify TNBC patients into high risk groups that showed over 5, 6, 7 and 8 times higher risk of developing metastasis to the bone, liver, lung and brain, respectively, than low-risk subgroups. These models for predicting site-specific metastasis retained significance following adjustment for tumour size, patient age and chemotherapy status. CONCLUSIONS Our novel IHC-based biomarkers signatures, when assessed in primary TNBC tumours, enable prediction of specific sites of metastasis, and potentially unravel biomarkers previously unknown in site tropism.
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Affiliation(s)
- Sergey Klimov
- Department of Biology, Georgia State University, Atlanta, GA 30303 USA
| | | | - Mohammed A Aleskandarany
- Department of Cellular Pathology, University of Nottingham and Nottingham University Hospitals NHS Trust, City Hospital Campus, Nottingham NG5 1PB, UK
| | - Andrew R Green
- Department of Cellular Pathology, University of Nottingham and Nottingham University Hospitals NHS Trust, City Hospital Campus, Nottingham NG5 1PB, UK
| | - Ian O Ellis
- Department of Cellular Pathology, University of Nottingham and Nottingham University Hospitals NHS Trust, City Hospital Campus, Nottingham NG5 1PB, UK
| | - Emiel Am Janssen
- Department of Pathology, Stavanger University Hospital, Stavanger N-4011, Norway
| | - Emad A Rakha
- Department of Cellular Pathology, University of Nottingham and Nottingham University Hospitals NHS Trust, City Hospital Campus, Nottingham NG5 1PB, UK
| | - Ritu Aneja
- Department of Biology, Georgia State University, Atlanta, GA 30303 USA
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Hou X, Li T, Ren Z, Liu Y. Novel BRCA2-Interacting Protein, LIMD1, Is Essential for the Centrosome Localization of BRCA2 in Esophageal Cancer Cell. Oncol Res 2017; 24:247-53. [PMID: 27656835 PMCID: PMC7838625 DOI: 10.3727/096504016x14652175055765] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mutation of breast cancer 2, early onset (BRCA2) has been identified as a vital risk factor for esophageal cancer (EC). To date, several proteins have been reported as BRCA2-interacting proteins and are associated with multiple biological processes. This study’s aim was to identify a novel interactive protein of BRCA2 and to explore its functional roles in EC. A yeast two-hybrid screening was performed to identify a novel BRCA2-interacting protein. Glutathione-S-transferase (GST) pull-down analysis was performed to find out how the binding domain of BRCA2 interacts with LIM domains containing 1 (LIMD1). The interaction between LIMD1 and BRCA2 at the endogenous level was confirmed by using coimmunoprecipitation and immunobloting. Furthermore, two different sequences of short hairpin RNAs (shRNAs) against LIMD1 were transfected into the human EC cell line ECA109. Afterward, the effects of LIMD1 suppression on the centrosome localization of BRCA2 and cell division were analyzed using an immunofluorescence microscope. Results showed that LIMD1 was a novel BRCA2-interacting protein, and LIMD1 interacted with the conserved region of BRCA2 (amino acids 2,750–3,094) in vitro. Importantly, after interfering with the protein expression of LIMD1 in ECA109 cells, the centrosome localization of BRCA2 was significantly abolished and abnormal cell division was significantly increased. These results suggested that LIMD1 is a novel BRCA2-interacting protein and is involved in the centrosome localization of BRCA2 and suppression of LIMD1, causing abnormal cell division in EC cells.
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Affiliation(s)
- Xiaobin Hou
- Department of Thoracic Surgery, Chinese PLA General Hospital, Beijing, China
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28
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Ma J, Yang J, Jian W, Wang X, Xiao D, Xia W, Xiong L, Ma D. A novel loss-of-function heterozygous BRCA2 c.8946_8947delAG mutation found in a Chinese woman with family history of breast cancer. J Cancer Res Clin Oncol 2017; 143:631-637. [PMID: 28058502 DOI: 10.1007/s00432-016-2327-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 12/19/2016] [Indexed: 12/28/2022]
Abstract
INTRODUCTION Breast cancer is the most frequent female malignancy worldwide. Among them, some cases have hereditary susceptibility in two leading genes, BRCA1 and BRCA2. Heterozygous germ line mutations in them are related with increased risk of breast, ovarian and other cancer, following autosomal dominant inheritance mode. METHODS AND RESULTS For purpose of early finding, early diagnosis and early treatment, mutation detecting of BRCA1/2 genes was performed in unselected 300 breast or ovarian patients and unaffected women using next-generation sequencing and then confirmed by Sanger sequencing. A non-previously reported heterozygous mutation c.8946_8947delAG (p.D2983FfsX34) of BRCA2 gene was identified in an unaffected Chinese woman with family history of breast cancer (her breast cancer mother, also carrying this mutation). The BRCA2-truncated protein resulted from the frame shift mutation was found to lose two putative nuclear localization signals and a Rad51-binding motif in the extreme C-terminal region by bioinformatic prediction. And then in vitro experiments showed that nearly all the mutant protein was unable to translocate to the nucleus to perform DNA repair activity. This novel mutant BRCA2 protein is dysfunction. CONCLUSIONS We classify the mutation into disease causing and conclude that it is the risk factor for breast cancer in this family. So, conducting the same mutation test and providing genetic counseling for this family is practically meaningful and significant. Meanwhile, the identification of this new mutation enriches the Breast Cancer Information Core database, especially in China.
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Affiliation(s)
- Jing Ma
- Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, Collaborative Innovation Center of Genetics and Development, Institutes of Biomedical Sciences, School of Basic Medical Sciences, Fudan University, Shanghai, China
- Center Laboratory, Bao'an Maternal and Children Healthcare Hospital, Key Laboratory of Birth Defects Research, Shenzhen, China
- Birth Defects Prevention Research and Transformation Team, Shenzhen, China
| | - Jichun Yang
- Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, Collaborative Innovation Center of Genetics and Development, Institutes of Biomedical Sciences, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Wenjing Jian
- Department of Breast Surgery, The First Affiliated Hospital of Shenzhen University, The Second People's Hospital, Shenzhen, China
- Breast Cancer Center, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Xianming Wang
- Department of Breast Surgery, The First Affiliated Hospital of Shenzhen University, The Second People's Hospital, Shenzhen, China
| | - Deyong Xiao
- Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, Collaborative Innovation Center of Genetics and Development, Institutes of Biomedical Sciences, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Wenjun Xia
- Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, Collaborative Innovation Center of Genetics and Development, Institutes of Biomedical Sciences, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Likuan Xiong
- Center Laboratory, Bao'an Maternal and Children Healthcare Hospital, Key Laboratory of Birth Defects Research, Shenzhen, China.
- Birth Defects Prevention Research and Transformation Team, Shenzhen, China.
| | - Duan Ma
- Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, Collaborative Innovation Center of Genetics and Development, Institutes of Biomedical Sciences, School of Basic Medical Sciences, Fudan University, Shanghai, China.
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Khotskaya YB, Mills GB, Mills Shaw KR. Next-Generation Sequencing and Result Interpretation in Clinical Oncology: Challenges of Personalized Cancer Therapy. Annu Rev Med 2016; 68:113-125. [PMID: 27813876 DOI: 10.1146/annurev-med-102115-021556] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The tools of next-generation sequencing (NGS) technology, such as targeted sequencing of candidate cancer genes and whole-exome and -genome sequencing, coupled with encouraging clinical results based on the use of targeted therapeutics and biomarker-guided clinical trials, are fueling further technological advancements of NGS technology. However, NGS data interpretation is associated with challenges that must be overcome to promote the techniques' effective integration into clinical oncology practice. Specifically, sequencing of a patient's tumor often yields 30-65 somatic variants, but most of these variants are "passenger" mutations that are phenotypically neutral and thus not targetable. Therefore, NGS data must be interpreted by multidisciplinary decision-support teams to determine mutation actionability and identify potential "drivers," so that the treating physician can prioritize what clinical decisions can be pursued in order to provide cancer therapy that is personalized to the patient and his or her unique genome.
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Affiliation(s)
| | - Gordon B Mills
- Sheikh Khalifa Bin Zayed Al Nahyan Institute for Personalized Cancer Therapy.,Department of Systems Biology, University of Texas, MD Anderson Cancer Center, Houston, Texas 77030;
| | - Kenna R Mills Shaw
- Sheikh Khalifa Bin Zayed Al Nahyan Institute for Personalized Cancer Therapy
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30
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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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Hall JC, Marlow LA, Mathias AC, Dawson LK, Durham WF, Meshaw KA, Mullin RJ, Synnott AJ, Small DL, Krishna M, von Hoff D, Schüler J, Hart SN, Couch FJ, Colon-Otero G, Copland JA. Novel patient-derived xenograft mouse model for pancreatic acinar cell carcinoma demonstrates single agent activity of oxaliplatin. J Transl Med 2016; 14:129. [PMID: 27165126 PMCID: PMC4862141 DOI: 10.1186/s12967-016-0875-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 04/25/2016] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Pancreatic acinar cell carcinoma (PACC) is a rare malignancy, accounting for <1 % of all pancreatic neoplasms. Very few retrospective studies are available to help guide management. We previously reported the case of a patient with metastatic PACC who achieved prolonged survival following doxorubicin treatment. Personalized treatment was based on molecular and in vitro data collected from primary cells developed from their liver metastasis. We now report the characterization of a patient derived tumor xenograft (PDTX) mouse model that originated from this patient's PACC liver metastasis. METHODS Fragments of biopsy tissue (5 mm(3)) from PACC liver metastasis were implanted into athymic nude mice. Tumors were grown and passaged from the host mice into new mice to be tested for therapeutic response. Immuno-histochemical (IHC) biomarkers were used to confirm that the PDTX model represents human PACC. The antitumor activities of multiple drugs (5-FU, irinotecan, oxaliplatin, gemcitabine, bevacizumab, erlotinib, doxorubicin and imatinib) were tested. Tumor size was measured over 74 days or until they reached an endpoint volume of ~800 mm(3). Tests to measure serum lipase levels and histological analyses of tumor tissues were also conducted to assess PACC progression and re-differentiation. RESULTS The model presented here expresses the same IHC markers found in human PACC. In the chemotherapy study, oxaliplatin produced a prolonged durable growth response associated with increased apoptosis, decreased serum lipase levels and increased healthy acinar cells. Bevacizumab also produced a significant growth response, but the effect was not prolonged as demonstrated by oxaliplatin treatment. The other chemotherapies had moderate to little effect, particularly after treatment ceased. Mutations in DNA repair genes are common in PACC and increase tumor susceptibility to oxaliplatin. To explore this we performed IHC and found no nuclear expression of BRCA2 in our model, indicating a mutation affecting nuclear localization. Gene sequencing confirms BRCA2 has a homozygous gene deletion on Exon 10, which frequently causes a protein truncation. CONCLUSIONS In summary, we report the development and characterization of the first and only preclinical PACC PDTX model. Here we show sustained anti-tumor activity of single agent oxaliplatin, a compound that is more effective in tumors that harbor mutations in DNA repair genes. Our data shows that BRCA2 is mutated in our PACC model, which could contribute to the oxaliplatin sensitivity observed. Further studies on this rare PACC model can serve to elucidate other novel therapies, biomarkers, and molecular mechanisms of signaling and drug resistance.
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Affiliation(s)
- Jason C. Hall
- />Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, 4500 San Pablo Road S., Jacksonville, FL 32224 USA
| | - Laura A. Marlow
- />Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, 4500 San Pablo Road S., Jacksonville, FL 32224 USA
| | - Adam C. Mathias
- />Charles River Discovery Services, 3300 Gateway Centre Blvd., Morrisville, NC 27560 USA
| | - Louis K. Dawson
- />Charles River Discovery Services, 3300 Gateway Centre Blvd., Morrisville, NC 27560 USA
| | - William F. Durham
- />Charles River Discovery Services, 3300 Gateway Centre Blvd., Morrisville, NC 27560 USA
| | - Kenneth A. Meshaw
- />Charles River Discovery Services, 3300 Gateway Centre Blvd., Morrisville, NC 27560 USA
| | - Robert J. Mullin
- />Charles River Discovery Services, 3300 Gateway Centre Blvd., Morrisville, NC 27560 USA
| | - Aidan J. Synnott
- />Charles River Discovery Services, 3300 Gateway Centre Blvd., Morrisville, NC 27560 USA
| | - Daniel L. Small
- />Charles River Discovery Services, 3300 Gateway Centre Blvd., Morrisville, NC 27560 USA
| | - Murli Krishna
- />Department of Laboratory Medicine and Pathology, Mayo Clinic, 4500 San Pablo Rd S., Jacksonville, FL 32224 USA
| | - Daniel von Hoff
- />The Translational Genomics Research Institute (TGen), 445 N 5th St., Phoenix, AZ 85004 USA
| | - Julia Schüler
- />Charles River Discovery Services, 3300 Gateway Centre Blvd., Morrisville, NC 27560 USA
| | - Steven N. Hart
- />Department of Laboratory Medicine and Pathology, 200 First Street SW, Rochester, MN 55905 USA
| | - Fergus J. Couch
- />Department of Laboratory Medicine and Pathology, 200 First Street SW, Rochester, MN 55905 USA
| | - Gerardo Colon-Otero
- />Division of Hematology/Oncology, Mayo Clinic, 4500 San Pablo Rd S., Jacksonville, FL 32224 USA
| | - John A. Copland
- />Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, 4500 San Pablo Road S., Jacksonville, FL 32224 USA
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Chatterjee G, Jimenez-Sainz J, Presti T, Nguyen T, Jensen RB. Distinct binding of BRCA2 BRC repeats to RAD51 generates differential DNA damage sensitivity. Nucleic Acids Res 2016; 44:5256-70. [PMID: 27084934 PMCID: PMC4914107 DOI: 10.1093/nar/gkw242] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 03/29/2016] [Indexed: 01/01/2023] Open
Abstract
BRCA2 is a multi-faceted protein critical for the proper regulation of homology-directed repair of DNA double-strand breaks. Elucidating the mechanistic features of BRCA2 is crucial for understanding homologous recombination and how patient-derived mutations impact future cancer risk. Eight centrally located BRC repeats in BRCA2 mediate binding and regulation of RAD51 on resected DNA substrates. Herein, we dissect the biochemical and cellular features of the BRC repeats tethered to the DNA binding domain of BRCA2. To understand how the BRC repeats and isolated domains of BRCA2 contribute to RAD51 binding, we analyzed both the biochemical and cellular properties of these proteins. In contrast to the individual BRC repeat units, we find that the BRC5-8 region potentiates RAD51-mediated DNA strand pairing and provides complementation functions exceeding those of BRC repeats 1-4. Furthermore, BRC5-8 can efficiently repair nuclease-induced DNA double-strand breaks and accelerate the assembly of RAD51 repair complexes upon DNA damage. These findings highlight the importance of the BRC5-8 domain in stabilizing the RAD51 filament and promoting homology-directed repair under conditions of cellular DNA damage.
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Affiliation(s)
- Gouri Chatterjee
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Judit Jimenez-Sainz
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Thomas Presti
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Tiffany Nguyen
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Ryan B Jensen
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
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Thorgeirsson T, Jordahl KM, Flavin R, Epstein MM, Fiorentino M, Andersson SO, Andren O, Rider JR, Mosquera JM, Ingoldsby H, Fall K, Tryggvadottir L, Mucci LA. Intracellular location of BRCA2 protein expression and prostate cancer progression in the Swedish Watchful Waiting Cohort. Carcinogenesis 2016; 37:262-8. [PMID: 26775038 DOI: 10.1093/carcin/bgw001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 01/02/2016] [Indexed: 01/07/2023] Open
Abstract
Prostate cancer patients with inherited BRCA2 mutations have a survival disadvantage. However, it is unknown whether progression is associated with BRCA2 protein expression in diagnostic prostate cancer tissue, among men without inherited mutations. We conducted a nested case-control study within the Swedish Watchful Waiting cohort. The case group included all 71 patients who died from prostate cancer within 5 years from diagnosis and controls were all patients (n = 165) who lived at least 7 years after diagnosis. Tissue microarrays were stained using antibodies for C- and N-terminal domains of the BRCA2 protein. Location (nuclear, cytoplasmic and membranous) and magnitude (intensity and percentage) of expression were assessed. Logistic regression models produced odds ratios (OR) and 95% confidence intervals (CI) adjusted for age, year of diagnosis and Gleason score. Positive BRCA2 staining at the cell membrane was associated with reduced risk of death within 5 years (N-terminal: OR = 0.47, 95% CI = 0.21-1.04, P = 0.06; C-terminal: OR = 0.41, 95% CI = 0.18-0.91, P = 0.03) and low Gleason scores (P = 0.006). Positive cytoplasmic C-terminal staining was associated with higher Gleason scores and increased lethality (OR = 3.61, 95% CI = 1.61-8.07, P = 0.002). BRCA2 protein expression at the cell membrane and lack of C-terminal expression in the cytoplasm were associated with a reduced risk of rapidly fatal prostate cancer. BRCA2 protein expression in prostate cancer tissue may have independent prognostic value. The potential biological significance of BRCA2 expression at the cell membrane warrants further investigation.
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Affiliation(s)
- Tryggvi Thorgeirsson
- Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA, Public Health Sciences, University of Iceland, 101 Reykjavik, Iceland
| | - Kristina M Jordahl
- Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA
| | - Richard Flavin
- Center for Molecular Oncologic Pathology, Dana Farber Cancer Institute, Boston, MA 02215, USA, Department of Histopathology, St. James's Hospital Dublin, Dublin 8, Ireland, Trinity College Dublin, Dublin, Ireland
| | - Mara Meyer Epstein
- Department of Medicine and the Meyers Primary Care Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Michelangelo Fiorentino
- Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA, "F. Addarii" Institute of Oncology and Transplantation Pathology, S.Orsola-Malpighi Hospital, Bologna University, 40126 Bologna, Italy
| | - Swen-Olof Andersson
- Department of Urology, Faculty of Medicine and Health, Örebro University, SE 701 82 Örebro, Sweden
| | - Ove Andren
- Department of Urology, Faculty of Medicine and Health, Örebro University, SE 701 82 Örebro, Sweden
| | - Jennifer R Rider
- Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA
| | - Juan Miguel Mosquera
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY 10065, USA, Institute for Precision Medicine of Weill Cornell Medical College and New York Presbyterian, New York, NY 10065, USA
| | - Helen Ingoldsby
- National University of Ireland, Shantalla Road, Galway, Ireland
| | - Katja Fall
- Clinical Epidemiology and Biostatistics, Faculty of Medicine and Health, Örebro University, SE 701 82 Örebro, Sweden
| | - Laufey Tryggvadottir
- Icelandic Cancer Registry, 105 Reykjavik, Iceland and Faculty of Medicine, University of Iceland, 101 Reykjavik, Iceland
| | - Lorelei A Mucci
- Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA, Public Health Sciences, University of Iceland, 101 Reykjavik, Iceland
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34
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Ghosh S, Bhunia AK, Paun BC, Gilbert SF, Dhru U, Patel K, Kern SE. Genome annotation by shotgun inactivation of a native gene in hemizygous cells: application to BRCA2 with implication of hypomorphic variants. Hum Mutat 2015; 36:260-9. [PMID: 25451944 DOI: 10.1002/humu.22736] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 11/19/2014] [Indexed: 12/30/2022]
Abstract
The greatest interpretive challenge of modern medicine may be to functionally annotate the vast variation of human genomes. Demonstrating a proposed approach, we created a library of BRCA2 exon 27 shotgun-mutant plasmids including solitary and multiplex mutations to generate human knockin clones using homologous recombination. This 55-mutation, 13-clone syngeneic variance library (SyVaL) comprised severely affected clones having early-stop nonsense mutations, functionally hypomorphic clones having multiple missense mutations emphasizing the potential to identify and assess hypomorphic mutations in novel proteomic and epidemiologic studies, and neutral clones having multiple missense mutations. Efficient coverage of nonessential amino acids was provided by mutation multiplexing. Severe mutations were distinguished from hypomorphic or neutral changes by chemosensitivity assays (hypersensitivity to mitomycin C and acetaldehyde), by analysis of RAD51 focus formation, and by mitotic multipolarity. A multiplex unbiased approach of generating all-human SyVaLs in medically important genes, with random mutations in native genes, would provide databases of variants that could be functionally annotated without concerns arising from exogenous cDNA constructs or interspecies interactions, as a basis for subsequent proteomic domain mapping or clinical calibration if desired. Such gene-irrelevant approaches could be scaled up for multiple genes of clinical interest, providing distributable cellular libraries linked to public-shared functional databases.
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Affiliation(s)
- Soma Ghosh
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland, 21287
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35
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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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36
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Jeong JH, Jo A, Park P, Lee H, Lee HO. Brca2 deficiency leads to T cell loss and immune dysfunction. Mol Cells 2015; 38:251-8. [PMID: 25666348 PMCID: PMC4363725 DOI: 10.14348/molcells.2015.2302] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 12/03/2014] [Accepted: 12/04/2014] [Indexed: 12/19/2022] Open
Abstract
Germline mutations in the breast cancer type 2 susceptibility gene (BRCA2) are linked to familial breast cancer and the progressive bone marrow failure syndrome Fanconi anaemia. Established Brca2 mouse knockout models show embryonic lethality, but those with a truncating mutation at the C-terminus survive to birth and develop thymic lymphoma at an early age. To overcome early lethality and investigate the function of BRCA2, we used T cell-specific conditional Brca2 knockout mice, which were previously shown to develop thymic lymphoma at a low penetrance. In the current study we showed that the number of peripheral T cells, particularly naïve pools, drastically declined with age. This decline was primarily ascribed to improper peripheral maintenance. Furthermore, heterozygous mice with one wild-type Brca2 allele manifested reduced T cell numbers, suggesting that Brca2 haploinsufficiency might also result in T cell loss. Our study reveals molecular events occurring in Brca2-deficient T cells and suggests that both heterozygous and homozygous Brca2 mutation may lead to dysfunction in T cell populations.
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Affiliation(s)
- Jun-hyeon Jeong
- Department of Biological Sciences and Institute of Molecular Biology and Genetics, Seoul National University, Seoul 151-742,
Korea
| | - Areum Jo
- Samsung Genome Institute, Samsung Medical Center, Seoul 135-710,
Korea
- SAIHST, Sungkyunkwan University School of Medicine, Seoul 135-710,
Korea
| | - Pilgu Park
- Department of Biological Sciences and Institute of Molecular Biology and Genetics, Seoul National University, Seoul 151-742,
Korea
| | - Hyunsook Lee
- Department of Biological Sciences and Institute of Molecular Biology and Genetics, Seoul National University, Seoul 151-742,
Korea
| | - Hae-Ock Lee
- Samsung Genome Institute, Samsung Medical Center, Seoul 135-710,
Korea
- SAIHST, Sungkyunkwan University School of Medicine, Seoul 135-710,
Korea
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37
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Wang Y, McKay JD, Rafnar T, Wang Z, Timofeeva M, Broderick P, Zong X, Laplana M, Wei Y, Han Y, Lloyd A, Delahaye-Sourdeix M, Chubb D, Gaborieau V, Wheeler W, Chatterjee N, Thorleifsson G, Sulem P, Liu G, Kaaks R, Henrion M, Kinnersley B, Vallée M, LeCalvez-Kelm F, Stevens VL, Gapstur SM, Chen WV, Zaridze D, Szeszenia-Dabrowska N, Lissowska J, Rudnai P, Fabianova E, Mates D, Bencko V, Foretova L, Janout V, Krokan HE, Gabrielsen ME, Skorpen F, Vatten L, Njølstad I, Chen C, Goodman G, Benhamou S, Vooder T, Valk K, Nelis M, Metspalu A, Lener M, Lubiński J, Johansson M, Vineis P, Agudo A, Clavel-Chapelon F, Bueno-de-Mesquita H, Trichopoulos D, Khaw KT, Johansson M, Weiderpass E, Tjønneland A, Riboli E, Lathrop M, Scelo G, Albanes D, Caporaso NE, Ye Y, Gu J, Wu X, Spitz MR, Dienemann H, Rosenberger A, Su L, Matakidou A, Eisen T, Stefansson K, Risch A, Chanock SJ, Christiani DC, Hung RJ, Brennan P, Landi MT, Houlston RS, Amos CI. Rare variants of large effect in BRCA2 and CHEK2 affect risk of lung cancer. Nat Genet 2014; 46:736-41. [PMID: 24880342 PMCID: PMC4074058 DOI: 10.1038/ng.3002] [Citation(s) in RCA: 311] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 05/08/2014] [Indexed: 12/16/2022]
Abstract
We conducted imputation to the 1000 Genomes Project of four genome-wide association studies of lung cancer in populations of European ancestry (11,348 cases and 15,861 controls) and genotyped an additional 10,246 cases and 38,295 controls for follow-up. We identified large-effect genome-wide associations for squamous lung cancer with the rare variants BRCA2 p.Lys3326X (rs11571833, odds ratio (OR) = 2.47, P = 4.74 × 10(-20)) and CHEK2 p.Ile157Thr (rs17879961, OR = 0.38, P = 1.27 × 10(-13)). We also showed an association between common variation at 3q28 (TP63, rs13314271, OR = 1.13, P = 7.22 × 10(-10)) and lung adenocarcinoma that had been previously reported only in Asians. These findings provide further evidence for inherited genetic susceptibility to lung cancer and its biological basis. Additionally, our analysis demonstrates that imputation can identify rare disease-causing variants with substantive effects on cancer risk from preexisting genome-wide association study data.
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Affiliation(s)
- Yufei Wang
- Division of Genetics and Epidemiology, Institute of Cancer Research, Sutton, Surrey, SM2 5NG, UK
| | - James D. McKay
- International Agency for Research on Cancer (IARC/WHO), Lyon, France
| | - Thorunn Rafnar
- deCODE genetics/Amgen, Sturlugata 8, 101 Reykjavik, Iceland
| | - Zhaoming Wang
- Division of Cancer Epidemiology and Genetics, National Cancer institute, NIH, DHHS, Bethesda, MD 20892-9769, USA
| | - Maria Timofeeva
- International Agency for Research on Cancer (IARC/WHO), Lyon, France
| | - Peter Broderick
- Division of Genetics and Epidemiology, Institute of Cancer Research, Sutton, Surrey, SM2 5NG, UK
| | - Xuchen Zong
- Lunenfeld-Tanenbaum Research Institute of Mount Sinai Hospital. Toronto, Canada
| | - Marina Laplana
- Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Yongyue Wei
- Department of Environmental Health, Harvard School of Public Health, Boston, MA, 617-432-1641, USA
| | - Younghun Han
- Center for Genomic Medicine Department of Community and Family Medicine, Geisel School of Medicine, Dartmouth College, 46 Centerra Parkway, Suite 330, Lebanon, NH 03766
| | - Amy Lloyd
- Division of Genetics and Epidemiology, Institute of Cancer Research, Sutton, Surrey, SM2 5NG, UK
| | | | - Daniel Chubb
- Division of Genetics and Epidemiology, Institute of Cancer Research, Sutton, Surrey, SM2 5NG, UK
| | - Valerie Gaborieau
- International Agency for Research on Cancer (IARC/WHO), Lyon, France
| | - William Wheeler
- Information Management Services, Inc., Rockville, MD 20852, USA
| | - Nilanjan Chatterjee
- Division of Cancer Epidemiology and Genetics, National Cancer institute, NIH, DHHS, Bethesda, MD 20892-9769, USA
| | | | - Patrick Sulem
- deCODE genetics/Amgen, Sturlugata 8, 101 Reykjavik, Iceland
| | - Geoffrey Liu
- Princess Margaret Hospital, University Health Network, Toronto, Canada
| | - Rudolf Kaaks
- Division of Cancer Epidemiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Translational Lung Research Center Heidelberg (TLRC-H), Member of the German Center for Lung Research (DZL), Heidelberg, Germany
| | - Marc Henrion
- Division of Genetics and Epidemiology, Institute of Cancer Research, Sutton, Surrey, SM2 5NG, UK
| | - Ben Kinnersley
- Division of Genetics and Epidemiology, Institute of Cancer Research, Sutton, Surrey, SM2 5NG, UK
| | - Maxime Vallée
- International Agency for Research on Cancer (IARC/WHO), Lyon, France
| | | | - Victoria L. Stevens
- Epidemiology Research Program, American Cancer Society, Atlanta, GA, 30301, USA
| | - Susan M. Gapstur
- Epidemiology Research Program, American Cancer Society, Atlanta, GA, 30301, USA
| | - Wei V. Chen
- Department of Genetics, U.T. M.D. Anderson Cancer Center, Houston, TX 77030
| | - David Zaridze
- Institute of Carcinogenesis, Russian N.N. Blokhin Cancer Research Centre, 115478 Moscow, Russia
| | | | - Jolanta Lissowska
- The M. Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw 02781, Poland
| | - Peter Rudnai
- National Institute of Environmental Health, Budapest 1097, Hungary
| | - Eleonora Fabianova
- Regional Authority of Public Health, Banska’ Bystrica 97556, Slovak Republic
| | - Dana Mates
- National Institute of Public Health, Bucharest 050463, Romania
| | - Vladimir Bencko
- 1st Faculty of Medicine, Institute of Hygiene and Epidemiology, Charles University in Prague, 12800 Prague 2, Czech Republic
| | - Lenka Foretova
- Department of Cancer Epidemiology and Genetics, Masaryk Memorial Cancer Institute, Brno 65653, Czech Republic
| | | | - Hans E. Krokan
- Department of Cancer Research and Molecular Medicine, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim 7489, Norway
| | - Maiken Elvestad Gabrielsen
- Department of Cancer Research and Molecular Medicine, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim 7489, Norway
| | - Frank Skorpen
- Department of Laboratory Medicine, Children’s and Women’s Health, Faculty of Medicine
| | - Lars Vatten
- Department of Public Health and General Practice, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim 7489, Norway
| | - Inger Njølstad
- Department of Community Medicine, University of Tromso, Tromso 9037, Norway
| | - Chu Chen
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Gary Goodman
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | | | - Tonu Vooder
- Institute of Molecular and Cell Biology, University of Tartu, Tartu 51010, Estonia
| | - Kristjan Valk
- Competence Centre on Reproductive Medicine and Biology, 50410 Tartu, Estonia
| | - Mari Nelis
- Estonian Genome Center, Institute of Molecular and Cell Biology, Tartu 51010, Estonia
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva, Switzerland
| | - Andres Metspalu
- Estonian Genome Center, Institute of Molecular and Cell Biology, Tartu 51010, Estonia
| | - Marcin Lener
- Department of Genetics and Pathology, International Hereditary Cancer Center, Pomeranian Medical University, Szczecin, Poland
| | - Jan Lubiński
- Department of Genetics and Pathology, International Hereditary Cancer Center, Pomeranian Medical University, Szczecin, Poland
| | - Mattias Johansson
- International Agency for Research on Cancer (IARC/WHO), Lyon, France
| | - Paolo Vineis
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College, London, UK
- HuGeF Foundation, Torino, Italy
| | - Antonio Agudo
- Unit of Nutrition, Environment and Cancer, Cancer Epidemiology Research Program, Catalan Institute of Oncology, Barcelona, Spain
| | - Francoise Clavel-Chapelon
- INSERM, Centre for research in Epidemiology and Population Health (CESP), U1018, Nutrition, Hormones and Women’s Health team, F-94805, Villejuif, France
- Université Paris Sud, UMRS 1018, F-94805, Villejuif, France
- IGR, F-94805, Villejuif, France
| | - H.Bas Bueno-de-Mesquita
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College, London, UK
- National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
- Department of Gastroenterology and Hepatology, University Medical Centre, Utrecht, The Netherlands
| | - Dimitrios Trichopoulos
- Department of Epidemiology, Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA
- Bureau of Epidemiologic Research, Academy of Athens, 23 Alexandroupoleos Street, Athens, GR-115 27, Greece
- Hellenic Health Foundation, 13 Kaisareias Street, Athens, GR-115 27, Greece
| | - Kay-Tee Khaw
- University of Cambridge School of Clinical Medicine, Clinical Gerontology Unit Box 251, Addenbrooke’s Hospital, Cambridge CB2 2QQ, UK
| | - Mikael Johansson
- Department of Radiation Sciences, Umeå universitet, SE-901 87 Umeå, Sverige, Sweden
| | - Elisabete Weiderpass
- Department of Community Medicine, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway
- Department of Research, Cancer Registry of Norway, Oslo, Norway
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
- Samfundet Folkhälsan, Helsinki, Finland
| | - Anne Tjønneland
- Danish Cancer Society Research Center, Strandboulevarden 49, DK 2100 Copenhagen Ø, Denmark
| | - Elio Riboli
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College, London, UK
| | - Mark Lathrop
- Centre d’Etude du Polymorphisme Humain (CEPH), Paris 75010, France
| | - Ghislaine Scelo
- International Agency for Research on Cancer (IARC/WHO), Lyon, France
| | - Demetrius Albanes
- Division of Cancer Epidemiology and Genetics, National Cancer institute, NIH, DHHS, Bethesda, MD 20892-9769, USA
| | - Neil E. Caporaso
- Division of Cancer Epidemiology and Genetics, National Cancer institute, NIH, DHHS, Bethesda, MD 20892-9769, USA
| | - Yuanqing Ye
- Department of Epidemiology, U.T. M.D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Jian Gu
- Department of Epidemiology, U.T. M.D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Xifeng Wu
- Department of Epidemiology, U.T. M.D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Margaret R. Spitz
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hendrik Dienemann
- Translational Lung Research Center Heidelberg (TLRC-H), Member of the German Center for Lung Research (DZL), Heidelberg, Germany
- Department of Thoracic Surgery, Thoraxklinik at University Hospital Heidelberg, Heidelberg, Germany
| | - Albert Rosenberger
- Department of Genetic Epidemiology, University of Göttingen, Göttingen, Germany
| | - Li Su
- Department of Environmental Health, Harvard School of Public Health, Boston, MA, 617-432-1641, USA
| | - Athena Matakidou
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, CB2 0RE, UK
| | - Timothy Eisen
- Department of Oncology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
- Addenbrooke’s Hospital, Cambridge Biomedical Campus, Hill’s Road Cambridge CB2 0QQ, UK
| | | | - Angela Risch
- Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Translational Lung Research Center Heidelberg (TLRC-H), Member of the German Center for Lung Research (DZL), Heidelberg, Germany
| | - Stephen J. Chanock
- Division of Cancer Epidemiology and Genetics, National Cancer institute, NIH, DHHS, Bethesda, MD 20892-9769, USA
| | - David C. Christiani
- Department of Environmental Health, Harvard School of Public Health, Boston, MA, 617-432-1641, USA
| | - Rayjean J. Hung
- Lunenfeld-Tanenbaum Research Institute of Mount Sinai Hospital. Toronto, Canada
| | - Paul Brennan
- International Agency for Research on Cancer (IARC/WHO), Lyon, France
| | - Maria Teresa Landi
- Division of Cancer Epidemiology and Genetics, National Cancer institute, NIH, DHHS, Bethesda, MD 20892-9769, USA
| | - Richard S. Houlston
- Division of Genetics and Epidemiology, Institute of Cancer Research, Sutton, Surrey, SM2 5NG, UK
| | - Christopher I. Amos
- Center for Genomic Medicine Department of Community and Family Medicine, Geisel School of Medicine, Dartmouth College, 46 Centerra Parkway, Suite 330, Lebanon, NH 03766
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38
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Jensen RB. BRCA2: one small step for DNA repair, one giant protein purified. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2013; 86:479-89. [PMID: 24348212 PMCID: PMC3848102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
DNA damage, malfunctions in DNA repair, and genomic instability are processes that intersect at the crossroads of carcinogenesis. Underscoring the importance of DNA repair in breast and ovarian tumorigenesis is the familial inherited cancer predisposition gene BRCA2. The role of BRCA2 in DNA double-strand break repair was first revealed based on its interaction with RAD51, a central player in homologous recombination. The RAD51 protein forms a nucleoprotein filament on single-stranded DNA, invades a DNA duplex, and initiates a search for homology. Once a homologous DNA sequence is found, the DNA is used as a template for the high-fidelity repair of the DNA break. Many of the biochemical features that allow BRCA2 to choreograph the activities of RAD51 have been elucidated and include: targeting RAD51 to single-stranded DNA while inhibiting binding to dsDNA, reducing the ATPase activity of RAD51, and facilitating the displacement of the single-strand DNA binding protein, Replication Protein A. These reinforcing activities of BRCA2 culminate in the correct positioning of RAD51 onto a processed DNA double-strand break and initiate its faithful repair by homologous recombination. In this review, I will address current biochemical data concerning the BRCA2 protein and highlight unanswered questions regarding BRCA2 function in homologous recombination and cancer.
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39
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Guidugli L, Carreira A, Caputo SM, Ehlen A, Galli A, Monteiro ANA, Neuhausen SL, Hansen TVO, Couch FJ, Vreeswijk MPG. Functional assays for analysis of variants of uncertain significance in BRCA2. Hum Mutat 2013; 35:151-64. [PMID: 24323938 DOI: 10.1002/humu.22478] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 10/28/2013] [Indexed: 01/11/2023]
Abstract
Missense variants in the BRCA2 gene are routinely detected during clinical screening for pathogenic mutations in patients with a family history of breast and ovarian cancer. These subtle changes frequently remain of unknown clinical significance because of the lack of genetic information that may help establish a direct correlation with cancer predisposition. Therefore, alternative ways of predicting the pathogenicity of these variants are urgently needed. Since BRCA2 is a protein involved in important cellular mechanisms such as DNA repair, replication, and cell cycle control, functional assays have been developed that exploit these cellular activities to explore the impact of the variants on protein function. In this review, we summarize assays developed and currently utilized for studying missense variants in BRCA2. We specifically depict details of each assay, including variants of uncertain significance analyzed, and describe a validation set of (genetically) proven pathogenic and neutral missense variants to serve as a golden standard for the validation of each assay. Guidelines are proposed to enable implementation of laboratory-based methods to assess the impact of the variant on cancer risk.
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Affiliation(s)
- Lucia Guidugli
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
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40
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Enginler SO, Akış I, Toydemir TSF, Oztabak K, Haktanir D, Gündüz MC, Kırşan I, Fırat I. Genetic variations of BRCA1 and BRCA2 genes in dogs with mammary tumours. Vet Res Commun 2013; 38:21-7. [PMID: 24122022 DOI: 10.1007/s11259-013-9577-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2013] [Indexed: 11/30/2022]
Abstract
Mammary tumours are the most common tumour type in female dogs. The formation of the mammary tumours is multifactorial but the high incidence of tumour disease in certain canine breeds suggests a strong genetic component. BRCA1 and BRCA2 are the most important genes significantly associated with mammary tumours. The aim of this study was to determine the association between the variations of these two genes and canine mammary tumours. 5'-untranslated region, intron 8 and exon 9 of BRCA1 and exons 12, 24, 27 of BRCA2 were sequenced in order to detect the genetic variations. In addition to six previously identified polymorphisms, six novel single nucleotide polymorphisms (SNPs) were detected. Five of the coding SNPs were synonymous and three of them were non-synonymous. The comparison of the sequences from 25 mammary tumour bearing and 10 tumour free dogs suggested that the two SNPs in intron 8 and exon 9 of BRCA1 and two SNPs in exon 24 and exon 27 of BRCA2, which are firstly identified in this study, might be associated with mammary tumour development in dogs. Especially one SNP in exon 9 of BRCA1 and one SNP in exon 24 of BRCA2 were found to be significantly associated with canine mammary tumours.
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Affiliation(s)
- S O Enginler
- Faculty of Veterinary Medicine, Department of Obstetrics and Gynaecology, Istanbul University, Avcılar, 34320, Istanbul, Turkey,
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41
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Jeyasekharan AD, Liu Y, Hattori H, Pisupati V, Jonsdottir AB, Rajendra E, Lee M, Sundaramoorthy E, Schlachter S, Kaminski C, Ofir-Rosenfeld Y, Sato K, Savill J, Ayoub N, Venkitaraman AR. A cancer-associated BRCA2 mutation reveals masked nuclear export signals controlling localization. Nat Struct Mol Biol 2013; 20:1191-8. [PMID: 24013206 PMCID: PMC3796201 DOI: 10.1038/nsmb.2666] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 07/25/2013] [Indexed: 02/02/2023]
Abstract
Germline missense mutations affecting a single BRCA2 allele predispose humans to cancer. Here we identify a protein-targeting mechanism that is disrupted by the cancer-associated mutation, BRCA2(D2723H), and that controls the nuclear localization of BRCA2 and its cargo, the recombination enzyme RAD51. A nuclear export signal (NES) in BRCA2 is masked by its interaction with a partner protein, DSS1, such that point mutations impairing BRCA2-DSS1 binding render BRCA2 cytoplasmic. In turn, cytoplasmic mislocalization of mutant BRCA2 inhibits the nuclear retention of RAD51 by exposing a similar NES in RAD51 that is usually obscured by the BRCA2-RAD51 interaction. Thus, a series of NES-masking interactions localizes BRCA2 and RAD51 in the nucleus. Notably, BRCA2(D2723H) decreases RAD51 nuclear retention even when wild-type BRCA2 is also present. Our findings suggest a mechanism for the regulation of the nucleocytoplasmic distribution of BRCA2 and RAD51 and its impairment by a heterozygous disease-associated mutation.
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Affiliation(s)
- Anand D Jeyasekharan
- The Medical Research Council Cancer Cell Unit, Hutchison-MRC Research Centre, Cambridge, UK
| | - Yang Liu
- The Medical Research Council Cancer Cell Unit, Hutchison-MRC Research Centre, Cambridge, UK
| | - Hiroyoshi Hattori
- The Medical Research Council Cancer Cell Unit, Hutchison-MRC Research Centre, Cambridge, UK
| | - Venkat Pisupati
- The Medical Research Council Cancer Cell Unit, Hutchison-MRC Research Centre, Cambridge, UK
| | - Asta Bjork Jonsdottir
- The Medical Research Council Cancer Cell Unit, Hutchison-MRC Research Centre, Cambridge, UK
| | - Eeson Rajendra
- The Medical Research Council Cancer Cell Unit, Hutchison-MRC Research Centre, Cambridge, UK
| | - Miyoung Lee
- The Medical Research Council Cancer Cell Unit, Hutchison-MRC Research Centre, Cambridge, UK
| | | | | | | | - Yaara Ofir-Rosenfeld
- The Medical Research Council Cancer Cell Unit, Hutchison-MRC Research Centre, Cambridge, UK
| | - Ko Sato
- The Medical Research Council Cancer Cell Unit, Hutchison-MRC Research Centre, Cambridge, UK
| | - Jane Savill
- The Medical Research Council Cancer Cell Unit, Hutchison-MRC Research Centre, Cambridge, UK
| | - Nabieh Ayoub
- The Medical Research Council Cancer Cell Unit, Hutchison-MRC Research Centre, Cambridge, UK
| | - Ashok R Venkitaraman
- The Medical Research Council Cancer Cell Unit, Hutchison-MRC Research Centre, Cambridge, UK
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42
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Tazzite A, Jouhadi H, Hamzi K, Benider A, Nadifi S. Effect of the novel Moroccan BRCA1 and BRCA2 frameshift mutations. INDIAN JOURNAL OF HUMAN GENETICS 2013; 19:274-5. [PMID: 24019637 PMCID: PMC3758742 DOI: 10.4103/0971-6866.116114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Amal Tazzite
- Genetics and Molecular Pathology Laboratory, Medical School of Casablanca, Morocco
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43
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Vietri MT, Molinari AM, Laura De Paola M, Cantile F, Fasano M, Cioffi M. Identification of a novel in-frame deletion in BRCA2 and analysis of variants of BRCA1/2 in Italian patients affected with hereditary breast and ovarian cancer. Clin Chem Lab Med 2013; 50:2171-80. [PMID: 23096105 DOI: 10.1515/cclm-2012-0154] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 06/28/2012] [Indexed: 12/18/2022]
Abstract
BACKGROUND An estimated 5 % – 10 % of all breast cancers are due to an inherited predisposition and, out of these, about 30 % are caused by germline mutations of the BRCA1 and BRCA2 genes. The prevalence of germline mutations in theBRCA1 and BRCA2 genes varies among ethnic groups. The aims of this study are to evaluate deleterious mutations and genomic rearrangements in BRCA1/2 genes and the CHEK21100delC mutation in a cohort of Italian women affected with hereditary breast and/or ovarian cancer. In addition we clarify the effect of the novel variants identified in BRCA2 gene bymRNA analysis and prediction software. METHODS We enrolled 103 consecutive Italian patients affected with hereditary breast and/or ovarian cancer, aged23 – 69 years. RESULTS We found BRCA1/2 mutations in 15/103 probands(14.6 % ). Among these, a BRCA2 gene mutation has not been described previously. In addition, we identified five novel BRCA2 variants (S1341, IVS1-59t > c, IVS11-74insA, IVS12 + 74c > g and I1167V). No genomic BRCA1/2re arrangements or CHEK2 1100delC mutation was found in our patients. The novel BRCA2 mutation NS1742del(p.N1742_S1743del) was an in-frame 6 bp deletion that results in loss of two amino acids. CONCLUSIONS In silico analysis conducted for S1341, IVS1-59t > c, IVS11-74insA and IVS12 + 74c > g of BRCA2 predicted the variants as neutral and benign, whereas the results for I1167V was inconclusive. mRNA analysis for the novel BRCA2 intronic variant IVS11-74insA and the already published BRCA1 variant C197 shows that they have no effect on the splicing. These results are in agreement with in silico analysis.
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Affiliation(s)
- Maria Teresa Vietri
- Dipartimento di Patologia Generale , Facoltà di Medicina e Chirurgia Seconda Università degli studi, Naples , Italy
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44
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Serbian high-risk families: extensive results on BRCA mutation spectra and frequency. J Hum Genet 2013; 58:501-7. [DOI: 10.1038/jhg.2013.30] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 03/18/2013] [Accepted: 04/03/2013] [Indexed: 01/01/2023]
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45
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Carlos AR, Escandell JM, Kotsantis P, Suwaki N, Bouwman P, Badie S, Folio C, Benitez J, Gomez-Lopez G, Pisano DG, Jonkers J, Tarsounas M. ARF triggers senescence in Brca2-deficient cells by altering the spectrum of p53 transcriptional targets. Nat Commun 2013; 4:2697. [PMID: 24162189 DOI: 10.1038/ncomms3697] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 10/02/2013] [Indexed: 01/12/2023] Open
Abstract
ARF is a tumour suppressor activated by oncogenic stress, which stabilizes p53. Although p53 is a key component of the response to DNA damage, a similar function for ARF has not been ascribed. Here we show that primary mouse and human cells lacking the tumour suppressor BRCA2 accumulate DNA damage, which triggers checkpoint signalling and ARF activation. Furthermore, senescence induced by Brca2 deletion in primary mouse and human cells is reversed by the loss of ARF, a phenotype recapitulated in cells lacking RAD51. Surprisingly, ARF is not necessary for p53 accumulation per se but for altering the spectrum of genes activated by this transcription factor. Specifically, ARF enables p53 transcription of Dusp4 and Dusp7, which encode a pair of phosphatases known to inactivate the MAP kinases ERK1/2. Our results ascribe a previously unanticipated function to the ARF tumour suppressor in genome integrity, controlled by replicative stress and ATM/ATR-dependent checkpoint responses.
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Affiliation(s)
- Ana Rita Carlos
- 1] Telomere and Genome Stability Group, The CR-UK/MRC Gray Institute for Radiation Oncology and Biology, Old Campus Road, Oxford OX3 7DQ, UK [2] [3]
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46
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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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47
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Siaud N, Barbera MA, Egashira A, Lam I, Christ N, Schlacher K, Xia B, Jasin M. Plasticity of BRCA2 function in homologous recombination: genetic interactions of the PALB2 and DNA binding domains. PLoS Genet 2011; 7:e1002409. [PMID: 22194698 PMCID: PMC3240595 DOI: 10.1371/journal.pgen.1002409] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 10/15/2011] [Indexed: 11/30/2022] Open
Abstract
The breast cancer suppressor BRCA2 is essential for the maintenance of genomic integrity in mammalian cells through its role in DNA repair by homologous recombination (HR). Human BRCA2 is 3,418 amino acids and is comprised of multiple domains that interact with the RAD51 recombinase and other proteins as well as with DNA. To gain insight into the cellular function of BRCA2 in HR, we created fusions consisting of various BRCA2 domains and also introduced mutations into these domains to disrupt specific protein and DNA interactions. We find that a BRCA2 fusion peptide deleted for the DNA binding domain and active in HR is completely dependent on interaction with the PALB2 tumor suppressor for activity. Conversely, a BRCA2 fusion peptide deleted for the PALB2 binding domain is dependent on an intact DNA binding domain, providing a role for this conserved domain in vivo; mutagenesis suggests that both single-stranded and double-stranded DNA binding activities in the DNA binding domain are required for its activity. Given that PALB2 itself binds DNA, these results suggest alternative mechanisms to deliver RAD51 to DNA. In addition, the BRCA2 C terminus contains both RAD51-dependent and -independent activities which are essential to HR in some contexts. Finally, binding the small peptide DSS1 is essential for activity when its binding domain is present, but not when it is absent. Our results reveal functional redundancy within the BRCA2 protein and emphasize the plasticity of this large protein built for optimal HR function in mammalian cells. The occurrence of disease-causing mutations throughout BRCA2 suggests sub-optimal HR from a variety of domain modulations. The breast tumor suppressor BRCA2 has a major role in DNA repair by homologous recombination (HR). BRCA2 is a large protein with multiple domains that interact with several proteins as well as with DNA, complicating our understanding of how the protein functions in cells. To investigate the mechanism by which BRCA2 functions in HR in cells, we created fusions consisting of various BRCA2 domains and also introduced mutations into these domains to disrupt specific protein and DNA interactions. We find that DNA binding by BRCA2 is critical when a BRCA2 peptide is deficient in binding another breast cancer suppressor, PALB2, but not when the peptide can bind PALB2, suggesting alternative mechanisms of activity. Binding the small peptide DSS1 is also essential for HR only in some contexts, as are activities in the BRCA2 C terminus. Our results reveal redundancy of BRCA2 domains and emphasize plasticity within this large protein built for optimal HR function in mammalian cells. The occurrence of disease-causing mutations throughout BRCA2 suggests sub-optimal HR from a variety of domain modulations.
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Affiliation(s)
- Nicolas Siaud
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Maria A. Barbera
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Akinori Egashira
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Isabel Lam
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
- Louis V. Gerstner Sloan-Kettering Graduate School of Biomedical Sciences, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Nicole Christ
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Katharina Schlacher
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Bing Xia
- Department of Radiation Oncology, The Cancer Institute of New Jersey, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, New Brunswick, New Jersey, United States of America
| | - Maria Jasin
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
- Louis V. Gerstner Sloan-Kettering Graduate School of Biomedical Sciences, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
- * E-mail:
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48
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Barber LJ, Rosa Rosa JM, Kozarewa I, Fenwick K, Assiotis I, Mitsopoulos C, Sims D, Hakas J, Zvelebil M, Lord CJ, Ashworth A. Comprehensive genomic analysis of a BRCA2 deficient human pancreatic cancer. PLoS One 2011; 6:e21639. [PMID: 21750719 PMCID: PMC3130048 DOI: 10.1371/journal.pone.0021639] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 06/03/2011] [Indexed: 01/06/2023] Open
Abstract
Capan-1 is a well-characterised BRCA2-deficient human cell line isolated from a liver metastasis of a pancreatic adenocarcinoma. Here we report a genome-wide assessment of structural variations and high-depth exome characterization of single nucleotide variants and small insertion/deletions in Capan-1. To identify potential somatic and tumour-associated variations in the absence of a matched-normal cell line, we devised a novel method based on the analysis of HapMap samples. We demonstrate that Capan-1 has one of the most rearranged genomes sequenced to date. Furthermore, small insertions and deletions are detected more frequently in the context of short sequence repeats than in other genomes. We also identify a number of novel mutations that may represent genetic changes that have contributed to tumour progression. These data provide insight into the genomic effects of loss of BRCA2 function.
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Affiliation(s)
- Louise J. Barber
- Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - Juan M. Rosa Rosa
- Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - Iwanka Kozarewa
- Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - Kerry Fenwick
- Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - Ioannis Assiotis
- Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - Costas Mitsopoulos
- Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - David Sims
- Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - Jarle Hakas
- Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - Marketa Zvelebil
- Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - Christopher J. Lord
- Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, London, United Kingdom
- * E-mail: (CJL); (AA)
| | - Alan Ashworth
- Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, London, United Kingdom
- * E-mail: (CJL); (AA)
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Two classes of BRC repeats in BRCA2 promote RAD51 nucleoprotein filament function by distinct mechanisms. Proc Natl Acad Sci U S A 2011; 108:10448-53. [PMID: 21670257 DOI: 10.1073/pnas.1106971108] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The human tumor suppressor protein BRCA2 plays a key role in recombinational DNA repair. BRCA2 recruits RAD51 to sites of DNA damage through interaction with eight conserved motifs of approximately 35 amino acids, the BRC repeats; however, the specific function of each repeat remains unclear. Here, we investigated the function of the individual BRC repeats by systematically analyzing their effects on RAD51 activities. Our results reveal the existence of two categories of BRC repeats that display unique functional characteristics. One group, comprising BRC1, -2, -3, and -4, binds to free RAD51 with high affinity. The second group, comprising BRC5, -6, -7, and -8, binds to free RAD51 with low affinity but binds to the RAD51-ssDNA filament with high affinity. Each member of the first group reduces the ATPase activity of RAD51, whereas none of the BRC repeats of the second group affects this activity. Thus, through different mechanisms, both types of BRC repeats bind to and stabilize the RAD51 nucleoprotein filament on ssDNA. In addition, members of the first group limit binding of RAD51 to duplex DNA, where members of the second group do not. Only the first group enhances DNA strand exchange by RAD51. Our results suggest that the two groups of BRC repeats have differentially evolved to ensure efficient formation of a nascent RAD51 filament on ssDNA by promoting its nucleation and growth, respectively. We propose that the BRC repeats cooperate in a partially redundant but reinforcing manner to ensure a high probability of RAD51 filament formation.
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50
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Beucher A, Deckbar D, Schumann E, Krempler A, Frankenberg-Schwager M, Löbrich M. Elevated radiation-induced γH2AX foci in G2 phase heterozygous BRCA2 fibroblasts. Radiother Oncol 2011; 101:46-50. [PMID: 21665305 DOI: 10.1016/j.radonc.2011.05.043] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 05/18/2011] [Accepted: 05/18/2011] [Indexed: 12/26/2022]
Abstract
BACKGROUND AND PURPOSE About 5-10% of all breast cancer cases are associated with heterozygous germ-line mutations in the genes encoding BRCA1 and BRCA2. Carriers of such mutations are highly predisposed for developing breast or ovarian cancer and, thus, are advised to undergo regular radio-diagnostic examinations. BRCA1 and BRCA2 are involved in multiple cellular processes including the repair of ionizing radiation (IR)-induced DNA double-strand breaks (DSBs) and different studies addressing the DSB repair capacity of BRCA1+/- or BRCA2+/- cells led to contradictory results. MATERIALS AND METHODS Using the sensitive method of γH2AX foci analysis in combination with cell cycle markers, we specifically measured DSB repair in confluent G0 as well as in exponentially growing G1 and G2 phase primary WT, BRCA1+/- and BRCA2+/- fibroblasts. RESULTS Both BRCA1+/- and BRCA2+/- cells displayed normal DSB repair in G0 and in G1. In contrast, in G2, BRCA2+/- but not BRCA1+/- cells exhibited a decreased DSB repair capacity which was in between that of WT and that of a hypomorphic BRCA2-/- cell line. CONCLUSIONS The residual amount of normal BRCA1 seems to be sufficient for efficient DSB repair in all cell cycle phases, while the decreased DSB repair capacity of heterozygous BRCA2 mutations suggests gene dosage effects in G2.
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Affiliation(s)
- Andrea Beucher
- Radiation Biology and DNA Repair, Darmstadt University of Technology, Germany
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