101
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Drost R, Dhillon KK, van der Gulden H, van der Heijden I, Brandsma I, Cruz C, Chondronasiou D, Castroviejo-Bermejo M, Boon U, Schut E, van der Burg E, Wientjens E, Pieterse M, Klijn C, Klarenbeek S, Loayza-Puch F, Elkon R, van Deemter L, Rottenberg S, van de Ven M, Dekkers DHW, Demmers JAA, van Gent DC, Agami R, Balmaña J, Serra V, Taniguchi T, Bouwman P, Jonkers J. BRCA1185delAG tumors may acquire therapy resistance through expression of RING-less BRCA1. J Clin Invest 2016; 126:2903-18. [PMID: 27454287 DOI: 10.1172/jci70196] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 05/09/2016] [Indexed: 12/19/2022] Open
Abstract
Heterozygous germline mutations in breast cancer 1 (BRCA1) strongly predispose women to breast cancer. BRCA1 plays an important role in DNA double-strand break (DSB) repair via homologous recombination (HR), which is important for tumor suppression. Although BRCA1-deficient cells are highly sensitive to treatment with DSB-inducing agents through their HR deficiency (HRD), BRCA1-associated tumors display heterogeneous responses to platinum drugs and poly(ADP-ribose) polymerase (PARP) inhibitors in clinical trials. It is unclear whether all pathogenic BRCA1 mutations have similar effects on the response to therapy. Here, we have investigated mammary tumorigenesis and therapy sensitivity in mice carrying the Brca1185stop and Brca15382stop alleles, which respectively mimic the 2 most common BRCA1 founder mutations, BRCA1185delAG and BRCA15382insC. Both the Brca1185stop and Brca15382stop mutations predisposed animals to mammary tumors, but Brca1185stop tumors responded markedly worse to HRD-targeted therapy than did Brca15382stop tumors. Mice expressing Brca1185stop mutations also developed therapy resistance more rapidly than did mice expressing Brca15382stop. We determined that both murine Brca1185stop tumors and human BRCA1185delAG breast cancer cells expressed a really interesting new gene domain-less (RING-less) BRCA1 protein that mediated resistance to HRD-targeted therapies. Together, these results suggest that expression of RING-less BRCA1 may serve as a marker to predict poor response to DSB-inducing therapy in human cancer patients.
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102
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Wang Y, Krais JJ, Bernhardy AJ, Nicolas E, Cai KQ, Harrell MI, Kim HH, George E, Swisher EM, Simpkins F, Johnson N. RING domain-deficient BRCA1 promotes PARP inhibitor and platinum resistance. J Clin Invest 2016; 126:3145-57. [PMID: 27454289 DOI: 10.1172/jci87033] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 05/09/2016] [Indexed: 12/18/2022] Open
Abstract
Patients with cancers that harbor breast cancer 1 (BRCA1) mutations initially respond well to platinum and poly(ADP-ribose) polymerase inhibitor (PARPi) therapy; however, resistance invariably arises in these patients and is a major clinical problem. The BRCA1185delAG allele is a common inherited mutation located close to the protein translation start site that is thought to produce a shortened, nonfunctional peptide. In this study, we investigated the mechanisms that lead to PARPi and platinum resistance in the SUM1315MO2 breast cancer cell line, which harbors a hemizygous BRCA1185delAG mutation. SUM1315MO2 cells were initially sensitive to PARPi and cisplatin but readily acquired resistance. PARPi- and cisplatin-resistant clones did not harbor secondary reversion mutations; rather, PARPi and platinum resistance required increased expression of a really interesting gene (RING) domain-deficient BRCA1 protein (Rdd-BRCA1). Initiation of translation occurred downstream of the frameshift mutation, probably at the BRCA1-Met-297 codon. In contrast to full-length BRCA1, Rdd-BRCA1 did not require BRCA1-associated RING domain 1 (BARD1) interaction for stability. Functionally, Rdd-BRCA1 formed irradiation-induced foci and supported RAD51 foci formation. Ectopic overexpression of Rdd-BRCA1 promoted partial PARPi and cisplatin resistance. Furthermore, Rdd-BRCA1 protein expression was detected in recurrent carcinomas from patients who carried germline BRCA1185delAG mutations. Taken together, these results indicate that RING-deficient BRCA1 proteins are hypomorphic and capable of contributing to PARPi and platinum resistance when expressed at high levels.
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103
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Her J, Soo Lee N, Kim Y, Kim H. Factors forming the BRCA1-A complex orchestrate BRCA1 recruitment to the sites of DNA damage. Acta Biochim Biophys Sin (Shanghai) 2016; 48:658-64. [PMID: 27325824 DOI: 10.1093/abbs/gmw047] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Accepted: 04/18/2016] [Indexed: 12/28/2022] Open
Abstract
Sustaining genomic integrity is essential for preventing onset of cancers. Therefore, human cells evolve to have refined biological pathways to defend genetic materials from various genomic insults. DNA damage response and DNA repair pathways essential for genome maintenance are accomplished by cooperative executions of multiple factors including breast cancer type 1 susceptibility protein (BRCA1). BRCA1 is initially identified as an altered gene in the hereditary breast cancer patients. Since then, tremendous efforts to understand the functions of BRAC1 reveal that BRCA1 is found in distinct complexes, including BRCA1-A, BRCA1-B, BRCA1-C, and the BRCA1/PALB2/BRCA2 complex, and plays diverse roles in a context-dependent manner. Among the complexes, BRCA1-A is critical for BRCA1 recruitment to the sites of DNA damage. Factors comprising the BRCA1-A include RAP80, CCDC98/Abraxas, BRCC36, BRCC45, BARD1, BRCA1, and MERIT40, a RAP80-associated factor. In this review, we summarize recent findings of the factors that form the BRCA1-A complex.
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Affiliation(s)
- Joonyoung Her
- Department of Biological Sciences, Sookmyung Women's University, Seoul 04310, Republic of Korea
| | - Nam Soo Lee
- Department of Biological Sciences, Sungkyunkwan University, Suwon 440-746, Republic of Korea
| | - Yonghwan Kim
- Department of Biological Sciences, Sookmyung Women's University, Seoul 04310, Republic of Korea
| | - Hongtae Kim
- Department of Biological Sciences, Sungkyunkwan University, Suwon 440-746, Republic of Korea Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Sungkyunkwan University, Suwon 440-746, Republic of Korea
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104
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Smeenk G, Mailand N. Writers, Readers, and Erasers of Histone Ubiquitylation in DNA Double-Strand Break Repair. Front Genet 2016; 7:122. [PMID: 27446204 PMCID: PMC4923129 DOI: 10.3389/fgene.2016.00122] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 06/15/2016] [Indexed: 12/16/2022] Open
Abstract
DNA double-strand breaks (DSBs) are highly cytotoxic DNA lesions, whose faulty repair may alter the content and organization of cellular genomes. To counteract this threat, numerous signaling and repair proteins are recruited hierarchically to the chromatin areas surrounding DSBs to facilitate accurate lesion repair and restoration of genome integrity. In vertebrate cells, ubiquitin-dependent modifications of histones adjacent to DSBs by RNF8, RNF168, and other ubiquitin ligases have a key role in promoting the assembly of repair protein complexes, serving as direct recruitment platforms for a range of genome caretaker proteins and their associated factors. These DNA damage-induced chromatin ubiquitylation marks provide an essential component of a histone code for DSB repair that is controlled by multifaceted regulatory circuits, underscoring its importance for genome stability maintenance. In this review, we provide a comprehensive account of how DSB-induced histone ubiquitylation is sensed, decoded and modulated by an elaborate array of repair factors and regulators. We discuss how these mechanisms impact DSB repair pathway choice and functionality for optimal protection of genome integrity, as well as cell and organismal fitness.
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Affiliation(s)
- Godelieve Smeenk
- Ubiquitin Signaling Group, Protein Signaling Program, Faculty of Health and Medical Sciences, The Novo Nordisk Foundation Center for Protein Research, University of Copenhagen Copenhagen, Denmark
| | - Niels Mailand
- Ubiquitin Signaling Group, Protein Signaling Program, Faculty of Health and Medical Sciences, The Novo Nordisk Foundation Center for Protein Research, University of Copenhagen Copenhagen, Denmark
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105
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Ying H, Dey P, Yao W, Kimmelman AC, Draetta GF, Maitra A, DePinho RA. Genetics and biology of pancreatic ductal adenocarcinoma. Genes Dev 2016; 30:355-85. [PMID: 26883357 PMCID: PMC4762423 DOI: 10.1101/gad.275776.115] [Citation(s) in RCA: 391] [Impact Index Per Article: 43.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Ying et al. review pancreatic ductal adenocarcinoma (PDAC) genetics and biology, particularly altered cancer cell metabolism, the complexity of immune regulation in the tumor microenvironment, and impaired DNA repair processes. With 5-year survival rates remaining constant at 6% and rising incidences associated with an epidemic in obesity and metabolic syndrome, pancreatic ductal adenocarcinoma (PDAC) is on track to become the second most common cause of cancer-related deaths by 2030. The high mortality rate of PDAC stems primarily from the lack of early diagnosis and ineffective treatment for advanced tumors. During the past decade, the comprehensive atlas of genomic alterations, the prominence of specific pathways, the preclinical validation of such emerging targets, sophisticated preclinical model systems, and the molecular classification of PDAC into specific disease subtypes have all converged to illuminate drug discovery programs with clearer clinical path hypotheses. A deeper understanding of cancer cell biology, particularly altered cancer cell metabolism and impaired DNA repair processes, is providing novel therapeutic strategies that show strong preclinical activity. Elucidation of tumor biology principles, most notably a deeper understanding of the complexity of immune regulation in the tumor microenvironment, has provided an exciting framework to reawaken the immune system to attack PDAC cancer cells. While the long road of translation lies ahead, the path to meaningful clinical progress has never been clearer to improve PDAC patient survival.
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Affiliation(s)
- Haoqiang Ying
- Department of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Prasenjit Dey
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Wantong Yao
- Department of Genomic Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Alec C Kimmelman
- Division of Genomic Stability and DNA Repair, Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA
| | - Giulio F Draetta
- Department of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA; Department of Genomic Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA; Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Anirban Maitra
- Department of Pathology and Translational Molecular Pathology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA; Sheikh Ahmed Pancreatic Cancer Research Center, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Ronald A DePinho
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
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106
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Yamamoto K, Wang J, Sprinzen L, Xu J, Haddock CJ, Li C, Lee BJ, Loredan DG, Jiang W, Vindigni A, Wang D, Rabadan R, Zha S. Kinase-dead ATM protein is highly oncogenic and can be preferentially targeted by Topo-isomerase I inhibitors. eLife 2016; 5. [PMID: 27304073 PMCID: PMC4957979 DOI: 10.7554/elife.14709] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 06/14/2016] [Indexed: 12/20/2022] Open
Abstract
Missense mutations in ATM kinase, a master regulator of DNA damage responses, are found in many cancers, but their impact on ATM function and implications for cancer therapy are largely unknown. Here we report that 72% of cancer-associated ATM mutations are missense mutations that are enriched around the kinase domain. Expression of kinase-dead ATM (Atm(KD/-)) is more oncogenic than loss of ATM (Atm(-/-)) in mouse models, leading to earlier and more frequent lymphomas with Pten deletions. Kinase-dead ATM protein (Atm-KD), but not loss of ATM (Atm-null), prevents replication-dependent removal of Topo-isomerase I-DNA adducts at the step of strand cleavage, leading to severe genomic instability and hypersensitivity to Topo-isomerase I inhibitors. Correspondingly, Topo-isomerase I inhibitors effectively and preferentially eliminate Atm(KD/-), but not Atm-proficientor Atm(-/-) leukemia in animal models. These findings identify ATM kinase-domain missense mutations as a potent oncogenic event and a biomarker for Topo-isomerase I inhibitor based therapy.
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Affiliation(s)
- Kenta Yamamoto
- Institute for Cancer Genetics, Columbia Unviersity, New York, United States.,Department of Pathology and Cell Biology, Columbia University, New York, United States.,College of Physicians and Surgeons, Columbia University, New York, United States.,Pathobiology and Molecular Medicine Graduate Program, Columbia University, New York, United States
| | - Jiguang Wang
- Department of Biomedical Informatics, Columbia University, New York, United States.,Department of Systems Biology, Columbia University, New York, United States.,College of Physicians & Surgeons, Columbia University, New York, United States
| | - Lisa Sprinzen
- Institute for Cancer Genetics, Columbia Unviersity, New York, United States.,Department of Pathology and Cell Biology, Columbia University, New York, United States.,College of Physicians and Surgeons, Columbia University, New York, United States.,Pathobiology and Molecular Medicine Graduate Program, Columbia University, New York, United States
| | - Jun Xu
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California San Diego, La Jolla, United States
| | - Christopher J Haddock
- Edward A Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, United States
| | - Chen Li
- Institute for Cancer Genetics, Columbia Unviersity, New York, United States.,Department of Pathology and Cell Biology, Columbia University, New York, United States.,College of Physicians and Surgeons, Columbia University, New York, United States
| | - Brian J Lee
- Institute for Cancer Genetics, Columbia Unviersity, New York, United States.,Department of Pathology and Cell Biology, Columbia University, New York, United States.,College of Physicians and Surgeons, Columbia University, New York, United States
| | - Denis G Loredan
- Institute for Cancer Genetics, Columbia Unviersity, New York, United States.,Department of Pathology and Cell Biology, Columbia University, New York, United States.,College of Physicians and Surgeons, Columbia University, New York, United States
| | - Wenxia Jiang
- Institute for Cancer Genetics, Columbia Unviersity, New York, United States.,Department of Pathology and Cell Biology, Columbia University, New York, United States.,College of Physicians and Surgeons, Columbia University, New York, United States
| | - Alessandro Vindigni
- Edward A Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, United States
| | - Dong Wang
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California San Diego, La Jolla, United States
| | - Raul Rabadan
- Department of Biomedical Informatics, Columbia University, New York, United States.,Department of Systems Biology, Columbia University, New York, United States.,College of Physicians & Surgeons, Columbia University, New York, United States
| | - Shan Zha
- Institute for Cancer Genetics, Columbia Unviersity, New York, United States.,Department of Pathology and Cell Biology, Columbia University, New York, United States.,College of Physicians and Surgeons, Columbia University, New York, United States.,Division of Pediatric Oncology, Hematology and Stem Cell Transplantation, Columbia University, New York, United States.,Department of Pediatrics, Columbia University, New York, United States.,College of Physicians & Surgeons, Columbia University, New York, United States
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107
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de la Hoya M, Soukarieh O, López-Perolio I, Vega A, Walker LC, van Ierland Y, Baralle D, Santamariña M, Lattimore V, Wijnen J, Whiley P, Blanco A, Raponi M, Hauke J, Wappenschmidt B, Becker A, Hansen TVO, Behar R, Investigators KC, Niederacher D, Arnold N, Dworniczak B, Steinemann D, Faust U, Rubinstein W, Hulick PJ, Houdayer C, Caputo SM, Castera L, Pesaran T, Chao E, Brewer C, Southey MC, van Asperen CJ, Singer CF, Sullivan J, Poplawski N, Mai P, Peto J, Johnson N, Burwinkel B, Surowy H, Bojesen SE, Flyger H, Lindblom A, Margolin S, Chang-Claude J, Rudolph A, Radice P, Galastri L, Olson JE, Hallberg E, Giles GG, Milne RL, Andrulis IL, Glendon G, Hall P, Czene K, Blows F, Shah M, Wang Q, Dennis J, Michailidou K, McGuffog L, Bolla MK, Antoniou AC, Easton DF, Couch FJ, Tavtigian S, Vreeswijk MP, Parsons M, Meeks HD, Martins A, Goldgar DE, Spurdle AB. Combined genetic and splicing analysis of BRCA1 c.[594-2A>C; 641A>G] highlights the relevance of naturally occurring in-frame transcripts for developing disease gene variant classification algorithms. Hum Mol Genet 2016; 25:2256-2268. [PMID: 27008870 PMCID: PMC5081057 DOI: 10.1093/hmg/ddw094] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 02/10/2016] [Accepted: 03/17/2016] [Indexed: 12/13/2022] Open
Abstract
A recent analysis using family history weighting and co-observation classification modeling indicated that BRCA1 c.594-2A > C (IVS9-2A > C), previously described to cause exon 10 skipping (a truncating alteration), displays characteristics inconsistent with those of a high risk pathogenic BRCA1 variant. We used large-scale genetic and clinical resources from the ENIGMA, CIMBA and BCAC consortia to assess pathogenicity of c.594-2A > C. The combined odds for causality considering case-control, segregation and breast tumor pathology information was 3.23 × 10-8 Our data indicate that c.594-2A > C is always in cis with c.641A > G. The spliceogenic effect of c.[594-2A > C;641A > G] was characterized using RNA analysis of human samples and splicing minigenes. As expected, c.[594-2A > C; 641A > G] caused exon 10 skipping, albeit not due to c.594-2A > C impairing the acceptor site but rather by c.641A > G modifying exon 10 splicing regulatory element(s). Multiple blood-based RNA assays indicated that the variant allele did not produce detectable levels of full-length transcripts, with a per allele BRCA1 expression profile composed of ≈70-80% truncating transcripts, and ≈20-30% of in-frame Δ9,10 transcripts predicted to encode a BRCA1 protein with tumor suppression function.We confirm that BRCA1c.[594-2A > C;641A > G] should not be considered a high-risk pathogenic variant. Importantly, results from our detailed mRNA analysis suggest that BRCA-associated cancer risk is likely not markedly increased for individuals who carry a truncating variant in BRCA1 exons 9 or 10, or any other BRCA1 allele that permits 20-30% of tumor suppressor function. More generally, our findings highlight the importance of assessing naturally occurring alternative splicing for clinical evaluation of variants in disease-causing genes.
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Affiliation(s)
- Miguel de la Hoya
- Molecular Oncology Laboratory, Instituto de Investigacion Sanitaria San Carlos (IdISSC), Hospital Clinico San Carlos, Madrid, Spain
| | - Omar Soukarieh
- Inserm U1079-IRIB, University of Rouen, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | - Irene López-Perolio
- Molecular Oncology Laboratory, Instituto de Investigacion Sanitaria San Carlos (IdISSC), Hospital Clinico San Carlos, Madrid, Spain
| | - Ana Vega
- Fundacion Publica Galega de Medicina Xenómica-SERGAS Grupo de Medicina Xenómica-USC, IDIS, CIBERER, Santiago de Compostela 15706, Spain
| | - Logan C Walker
- Department of Pathology, University of Otago, Christchurch 8140, New Zealand
| | - Yvette van Ierland
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden 2300, The Netherlands
| | - Diana Baralle
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton S016 5YA, UK
| | - Marta Santamariña
- CIBERER, Grupo de Medicina Xenómica-USC, Universidade de Santiago de Compostela, Fundacion Galega de Medicina Xenómica (SERGAS), Santiago de Compostela 15706, Spain
| | - Vanessa Lattimore
- Department of Pathology, University of Otago, Christchurch 8140, New Zealand
| | - Juul Wijnen
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden 2300, The Netherlands Department of Clinical Genetics, Leiden University Medical Centre, Leiden 2300, The Netherlands
| | - Philip Whiley
- Department of Genetics and Computational Biology, QIMR Berghofer Medical Research Institute, Brisbane, QLD 4006, Australia
| | - Ana Blanco
- Fundacion Publica Galega de Medicina Xenómica-SERGAS Grupo de Medicina Xenómica-USC, IDIS, CIBERER, Santiago de Compostela 15706, Spain
| | - Michela Raponi
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton S016 5YA, UK
| | - Jan Hauke
- Center for Hereditary Breast and Ovarian Cancer, Center for Integrated Oncology (CIO), Medical Faculty, University Hosptial Cologne, Cologne 50931, Germany
| | - Barbara Wappenschmidt
- Center for Hereditary Breast and Ovarian Cancer, Center for Integrated Oncology (CIO), Medical Faculty, University Hosptial Cologne, Cologne 50931, Germany
| | - Alexandra Becker
- Center for Hereditary Breast and Ovarian Cancer, Center for Integrated Oncology (CIO), Medical Faculty, University Hosptial Cologne, Cologne 50931, Germany
| | - Thomas V O Hansen
- Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen DK-2100, Denmark
| | - Raquel Behar
- Molecular Oncology Laboratory, Instituto de Investigacion Sanitaria San Carlos (IdISSC), Hospital Clinico San Carlos, Madrid, Spain
| | - KConFaB Investigators
- Peter MacCallum Cancer Center, University of Melbourne, Melbourne, VIC 3002, Australia
| | - Diether Niederacher
- Department of Gynaecology and Obstetrics, University Hospital Düsseldorf, Heinrich-Heine University Düsseldorf, Düsseldorf 40225, Germany
| | - Norbert Arnold
- Department of Gynaecology and Obstetrics, University Hospital of Schleswig-Holstein, Campus Kiel, Christian-Albrechts University Kiel, Kiel 24105, Germany
| | - Bernd Dworniczak
- Institute of Human Genetics, University of Münster, Münster 48149, Germany
| | - Doris Steinemann
- Institute of Human Genetics, Hannover Medical School, Hannover 30625, Germany
| | - Ulrike Faust
- Institute of Medical Genetics and Applied Genomics, University Hospital Tuebingen, Tuebingen 72076, Germany
| | | | - Peter J Hulick
- Center for Medical Genetics, NorthShore University Health System, University of Chicago Pritzker School of Medicine, Evanston, IL 60201, USA
| | - Claude Houdayer
- Service de Génétique, Department de Biologie des Tumeurs, Institut Curie and INSERM U830, Centre de Recherche de l'Institut Curie, Paris, and Universite Paris Descartes, Sorbonne Paris Cite, Paris 75248, France
| | - Sandrine M Caputo
- Service de Génétique, Department de Biologie des Tumeurs, Institut Curie, Paris 75248, France
| | - Laurent Castera
- Centre Francois Baclesse, Laboratoire de Biologie et de Genetique du Cancer, 14076 Caen, Paris 75248, France
| | | | | | - Carole Brewer
- Department of Clinical Genetics, Royal Devon and Exeter Hospital, Exeter, UK
| | - Melissa C Southey
- Genetic Epidemiology Laboratory, Department of Pathology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Christi J van Asperen
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden 2300, The Netherlands
| | - Christian F Singer
- Department of Obstetrics and Gynaecology, Medical University of Vienna, Vienna, Austria, Waehringer Guertel 18-20, A 1090 Vienna, Austria
| | - Jan Sullivan
- Genetic Health Service NZ, South Island Hub, Christchurch Hospital, Christchurch 8140, New Zealand
| | - Nicola Poplawski
- Adult Genetics Unit, South Australian Clinical Genetics Service, SA Pathology at the Women's and Children's Hospital, North Adelaide, SA 5067, Australia University Department of Paediatrics, University of Adelaide, North Terrace, Adelaide, SA 5000, Australia
| | - Phuong Mai
- Clinical Genetics Branch, DCEG, NCI, NIH, Bethesda, MD, USA
| | - Julian Peto
- London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Nichola Johnson
- Breakthrough Breast Cancer Research Centre, Institute of Cancer Research, London SW3 6JB, UK Division of Breast Cancer Research, Institute of Cancer Research, London SW3 6JB, UK
| | - Barbara Burwinkel
- Molecular Biology of Breast Cancer, Department of Gynecology and Obstetrics, University of Heidelberg, Heidelberg 69120, Germany Molecular Epidemiology Group, German Cancer Research Center, DKFZ, Heidelberg 69120, Germany
| | - Harald Surowy
- Molecular Biology of Breast Cancer, Department of Gynecology and Obstetrics, University of Heidelberg, Heidelberg 69120, Germany Molecular Epidemiology Group, German Cancer Research Center, DKFZ, Heidelberg 69120, Germany
| | - Stig E Bojesen
- Copenhagen General Population Study, Herlev and Gentofte Hospital, Copenhagen 2730, Denmark Department of Clinical Biochemistry, Herlev Hospital, Copenhagen University Hospital, Herlev 2730, Denmark Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 1165, Denmark
| | - Henrik Flyger
- Department of Breast Surgery, Herlev and Gentofte Hospital, Copenhagen University Hospital, 2730 Denmark
| | - Annika Lindblom
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm SE-171 77, Sweden
| | - Sara Margolin
- Department of Oncology Pathology, Karolinska Institutet, Stockholm SE-171 77, Sweden
| | - Jenny Chang-Claude
- Division of Cancer Epidemiology, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany University Cancer Center Hamburg (UCCH), University Medical Center Hamburg-Eppendorf, Hamburg 20246, Germany
| | - Anja Rudolph
- Division of Cancer Epidemiology, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Paolo Radice
- Unit of "Molecular bases of genetic risk and genetic testing", Department of Preventive and Predictive Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milano 20139, Italy
| | - Laura Galastri
- Associazione Volontari Italiani Sangue (AVIS) comunale di Milano, Milano 20139, Italy
| | - Janet E Olson
- Department of Health Sciences Research, Mayo Clinic, Rochester, MN 55905, USA
| | - Emily Hallberg
- Department of Health Sciences Research, Mayo Clinic, Rochester, MN 55905, USA
| | - Graham G Giles
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, VIC 3010, Australia Cancer Epidemiology Centre, Cancer Council Victoria, Melbourne, VIC 3004, Australia
| | - Roger L Milne
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, VIC 3010, Australia Cancer Epidemiology Centre, Cancer Council Victoria, Melbourne, VIC 3004, Australia
| | - Irene L Andrulis
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada Department of Molecular Genetics, University of Toronto, M5B 1W8, Canada
| | - Gord Glendon
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
| | - Per Hall
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm SE-171 77, Sweden
| | - Kamila Czene
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm SE-171 77, Sweden
| | - Fiona Blows
- Centre for Cancer Genetic Epidemiology, Department of Oncology, University of Cambridge, Cambridge CB1 8RN, UK
| | - Mitul Shah
- Centre for Cancer Genetic Epidemiology, Department of Oncology, University of Cambridge, Cambridge CB1 8RN, UK
| | - Qin Wang
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK
| | - Joe Dennis
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK
| | - Kyriaki Michailidou
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK Department of Electron Microscopy/Molecular Pathology, The Cyprus Institute of Neurology and Genetics, 1683, Nicosia, Cyprus
| | - Lesley McGuffog
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK
| | - Manjeet K Bolla
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK
| | - Antonis C Antoniou
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK
| | - Douglas F Easton
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK
| | - Fergus J Couch
- Department of Health Sciences Research, Mayo Clinic, Rochester, MN 55905, USA Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA
| | | | - Maaike P Vreeswijk
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden 2300, The Netherlands
| | - Michael Parsons
- Department of Genetics and Computational Biology, QIMR Berghofer Medical Research Institute, Brisbane, QLD 4006, Australia
| | | | - Alexandra Martins
- Inserm U1079-IRIB, University of Rouen, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | - David E Goldgar
- Department of Dermatology, Huntsman Cancer Institute, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Amanda B Spurdle
- Department of Genetics and Computational Biology, QIMR Berghofer Medical Research Institute, Brisbane, QLD 4006, Australia
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108
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Agarwal P, Miller KM. The nucleosome: orchestrating DNA damage signaling and repair within chromatin. Biochem Cell Biol 2016; 94:381-395. [PMID: 27240007 DOI: 10.1139/bcb-2016-0017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
DNA damage occurs within the chromatin environment, which ultimately participates in regulating DNA damage response (DDR) pathways and repair of the lesion. DNA damage activates a cascade of signaling events that extensively modulates chromatin structure and organization to coordinate DDR factor recruitment to the break and repair, whilst also promoting the maintenance of normal chromatin functions within the damaged region. For example, DDR pathways must avoid conflicts between other DNA-based processes that function within the context of chromatin, including transcription and replication. The molecular mechanisms governing the recognition, target specificity, and recruitment of DDR factors and enzymes to the fundamental repeating unit of chromatin, i.e., the nucleosome, are poorly understood. Here we present our current view of how chromatin recognition by DDR factors is achieved at the level of the nucleosome. Emerging evidence suggests that the nucleosome surface, including the nucleosome acidic patch, promotes the binding and activity of several DNA damage factors on chromatin. Thus, in addition to interactions with damaged DNA and histone modifications, nucleosome recognition by DDR factors plays a key role in orchestrating the requisite chromatin response to maintain both genome and epigenome integrity.
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Affiliation(s)
- Poonam Agarwal
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, University of Texas at Austin, 2506 Speedway Stop A5000, Austin, TX 78712, USA.,Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, University of Texas at Austin, 2506 Speedway Stop A5000, Austin, TX 78712, USA
| | - Kyle M Miller
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, University of Texas at Austin, 2506 Speedway Stop A5000, Austin, TX 78712, USA.,Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, University of Texas at Austin, 2506 Speedway Stop A5000, Austin, TX 78712, USA
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109
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New concepts on BARD1: Regulator of BRCA pathways and beyond. Int J Biochem Cell Biol 2016; 72:1-17. [DOI: 10.1016/j.biocel.2015.12.008] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 12/15/2015] [Accepted: 12/16/2015] [Indexed: 01/09/2023]
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110
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Wu Q, Paul A, Su D, Mehmood S, Foo TK, Ochi T, Bunting EL, Xia B, Robinson CV, Wang B, Blundell TL. Structure of BRCA1-BRCT/Abraxas Complex Reveals Phosphorylation-Dependent BRCT Dimerization at DNA Damage Sites. Mol Cell 2016; 61:434-448. [PMID: 26778126 PMCID: PMC4747905 DOI: 10.1016/j.molcel.2015.12.017] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 10/22/2015] [Accepted: 12/09/2015] [Indexed: 01/22/2023]
Abstract
BRCA1 accumulation at DNA damage sites is an important step for its function in the DNA damage response and in DNA repair. BRCA1-BRCT domains bind to proteins containing the phosphorylated serine-proline-x-phenylalanine (pSPxF) motif including Abraxas, Bach1/FancJ, and CtIP. In this study, we demonstrate that ionizing radiation (IR)-induces ATM-dependent phosphorylation of serine 404 (S404) next to the pSPxF motif. Crystal structures of BRCT/Abraxas show that phosphorylation of S404 is important for extensive interactions through the N-terminal sequence outside the pSPxF motif and leads to formation of a stable dimer. Mutation of S404 leads to deficiency in BRCA1 accumulation at DNA damage sites and cellular sensitivity to IR. In addition, two germline mutations of BRCA1 are found to disrupt the dimer interface and dimer formation. Thus, we demonstrate a mechanism involving IR-induced phosphorylation and dimerization of the BRCT/Abraxas complex for regulating Abraxas-mediated recruitment of BRCA1 in response to IR.
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Affiliation(s)
- Qian Wu
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, CB2 1GA Cambridge, UK
| | - Atanu Paul
- Department of Genetics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA; Genes and Development Program, The University of Texas Graduate School of Biomedical Sciences at Houston, 6767 Bertner Avenue, Houston, TX 77030, USA
| | - Dan Su
- Department of Genetics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Shahid Mehmood
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, OX1 3QZ Oxford, UK
| | - Tzeh Keong Foo
- Department of Radiation Oncology, Robert Wood Johnson Medical School, Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08903, USA
| | - Takashi Ochi
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, CB2 1GA Cambridge, UK
| | - Emma L Bunting
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, CB2 1GA Cambridge, UK
| | - Bing Xia
- Department of Radiation Oncology, Robert Wood Johnson Medical School, Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08903, USA
| | - Carol V Robinson
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, OX1 3QZ Oxford, UK
| | - Bin Wang
- Department of Genetics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA; Genes and Development Program, The University of Texas Graduate School of Biomedical Sciences at Houston, 6767 Bertner Avenue, Houston, TX 77030, USA.
| | - Tom L Blundell
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, CB2 1GA Cambridge, UK.
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111
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Duann P, Li H, Lin P, Tan T, Wang Z, Chen K, Zhou X, Gumpper K, Zhu H, Ludwig T, Mohler PJ, Rovin B, Abraham WT, Zeng C, Ma J. MG53-mediated cell membrane repair protects against acute kidney injury. Sci Transl Med 2015; 7:279ra36. [PMID: 25787762 DOI: 10.1126/scitranslmed.3010755] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Injury to the renal proximal tubular epithelium (PTE) represents the underlying consequence of acute kidney injury (AKI) after exposure to various stressors, including nephrotoxins and ischemia/reperfusion (I/R). Although the kidney has the ability to repair itself after mild injury, insufficient repair of PTE cells may trigger inflammatory and fibrotic responses, leading to chronic renal failure. We report that MG53, a member of the TRIM family of proteins, participates in repair of injured PTE cells and protects against the development of AKI. We show that MG53 translocates to acute injury sites on PTE cells and forms a repair patch. Ablation of MG53 leads to defective membrane repair. MG53-deficient mice develop pronounced tubulointerstitial injury and increased susceptibility to I/R-induced AKI compared to wild-type mice. Recombinant human MG53 (rhMG53) protein can target injury sites on PTE cells to facilitate repair after I/R injury or nephrotoxin exposure. Moreover, in animal studies, intravenous delivery of rhMG53 ameliorates cisplatin-induced AKI without affecting the tumor suppressor efficacy of cisplatin. These findings identify MG53 as a vital component of reno-protection, and targeting MG53-mediated repair of PTE cells represents a potential approach to prevention and treatment of AKI.
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Affiliation(s)
- Pu Duann
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Haichang Li
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Peihui Lin
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Tao Tan
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Zhen Wang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing Institute of Cardiology, Chongqing 400042, China
| | - Ken Chen
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing Institute of Cardiology, Chongqing 400042, China
| | - Xinyu Zhou
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Kristyn Gumpper
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Hua Zhu
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Thomas Ludwig
- Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Peter J Mohler
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA.,Department of Medicine, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Brad Rovin
- Department of Medicine, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - William T Abraham
- Department of Medicine, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing Institute of Cardiology, Chongqing 400042, China
| | - Jianjie Ma
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA.,Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH 43210, USA
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112
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Alkema NG, Wisman GBA, van der Zee AGJ, van Vugt MATM, de Jong S. Studying platinum sensitivity and resistance in high-grade serous ovarian cancer: Different models for different questions. Drug Resist Updat 2015; 24:55-69. [PMID: 26830315 DOI: 10.1016/j.drup.2015.11.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 11/04/2015] [Accepted: 11/19/2015] [Indexed: 12/21/2022]
Abstract
High-grade serous ovarian cancer (HGSOC) has the highest mortality rate among all gynecological cancers. Patients are generally diagnosed in an advanced stage with the majority of cases displaying platinum resistant relapses. Recent genomic interrogation of large numbers of HGSOC patient samples indicated high complexity in terms of genetic aberrations, intra- and intertumor heterogeneity and underscored their lack of targetable oncogenic mutations. Sub-classifications of HGSOC based on expression profiles, termed 'differentiated', 'immunoreactive', 'mesenchymal' and 'proliferative', were shown to have prognostic value. In addition, in almost half of all HGSOC patients, a deficiency in homologous recombination (HR) was found that potentially can be targeted using PARP inhibitors. Developing precision medicine requires advanced experimental models. In the current review, we discuss experimental HGSOC models in which resistance to platinum therapy and the use of novel therapeutics can be carefully studied. Panels of better-defined primary cell lines need to be established to capture the full spectrum of HGSOC subtypes. Further refinement of cell lines is obtained with a 3-dimensional culture model mimicking the tumor microenvironment. Alternatively, ex vivo ovarian tumor tissue slices are used. For in vivo studies, larger panels of ovarian cancer patient-derived xenografts (PDXs) are being established, encompassing all expression subtypes. Ovarian cancer PDXs grossly retain tumor heterogeneity and clinical response to platinum therapy is preserved. PDXs are currently used in drug screens and as avatars for patient response. The role of the immune system in tumor responses can be assessed using humanized PDXs and immunocompetent genetically engineered mouse models. Dynamic tracking of genetic alterations in PDXs as well as patients during treatment and after relapse is feasible by sequencing circulating cell-free tumor DNA and analyzing circulating tumor cells. We discuss how various models and methods can be combined to delineate the molecular mechanisms underlying platinum resistance and to select HGSOC patients other than BRCA1/2-mutation carriers that could potentially benefit from the synthetic lethality of PARP inhibitors. This integrated approach is a first step to improve therapy outcomes in specific subgroups of HGSOC patients.
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Affiliation(s)
- Nicolette G Alkema
- Department of Gynecologic Oncology, Cancer Research Centre Groningen, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - G Bea A Wisman
- Department of Gynecologic Oncology, Cancer Research Centre Groningen, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Ate G J van der Zee
- Department of Gynecologic Oncology, Cancer Research Centre Groningen, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Marcel A T M van Vugt
- Department of Medical Oncology, Cancer Research Centre Groningen, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Steven de Jong
- Department of Medical Oncology, Cancer Research Centre Groningen, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
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113
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Qi J, Ronai ZA. Dysregulation of ubiquitin ligases in cancer. Drug Resist Updat 2015; 23:1-11. [PMID: 26690337 DOI: 10.1016/j.drup.2015.09.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Revised: 08/31/2015] [Accepted: 09/02/2015] [Indexed: 02/08/2023]
Abstract
Ubiquitin ligases (UBLs) are critical components of the ubiquitin proteasome system (UPS), which governs fundamental processes regulating normal cellular homeostasis, metabolism, and cell cycle in response to external stress signals and DNA damage. Among multiple steps of the UPS system required to regulate protein ubiquitination and stability, UBLs define specificity, as they recognize and interact with substrates in a temporally- and spatially-regulated manner. Such interactions are required for substrate modification by ubiquitin chains, which marks proteins for recognition and degradation by the proteasome or alters their subcellular localization or assembly into functional complexes. UBLs are often deregulated in cancer, altering substrate availability or activity in a manner that can promote cellular transformation. Such deregulation can occur at the epigenetic, genomic, or post-translational levels. Alterations in UBL can be used to predict their contributions, affecting tumor suppressors or oncogenes in select tumors. Better understanding of mechanisms underlying UBL expression and activities is expected to drive the development of next generation modulators that can serve as novel therapeutic modalities. This review summarizes our current understanding of UBL deregulation in cancer and highlights novel opportunities for therapeutic interventions.
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Affiliation(s)
- Jianfei Qi
- University of Maryland School of Medicine, Baltimore, 21201, USA.
| | - Ze'ev A Ronai
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, 92037, USA.
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114
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Coluccio ML, Gentile F, Das G, Nicastri A, Perri AM, Candeloro P, Perozziello G, Proietti Zaccaria R, Gongora JST, Alrasheed S, Fratalocchi A, Limongi T, Cuda G, Di Fabrizio E. Detection of single amino acid mutation in human breast cancer by disordered plasmonic self-similar chain. SCIENCE ADVANCES 2015; 1:e1500487. [PMID: 26601267 PMCID: PMC4643778 DOI: 10.1126/sciadv.1500487] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 06/13/2015] [Indexed: 05/15/2023]
Abstract
Control of the architecture and electromagnetic behavior of nanostructures offers the possibility of designing and fabricating sensors that, owing to their intrinsic behavior, provide solutions to new problems in various fields. We show detection of peptides in multicomponent mixtures derived from human samples for early diagnosis of breast cancer. The architecture of sensors is based on a matrix array where pixels constitute a plasmonic device showing a strong electric field enhancement localized in an area of a few square nanometers. The method allows detection of single point mutations in peptides composing the BRCA1 protein. The sensitivity demonstrated falls in the picomolar (10(-12) M) range. The success of this approach is a result of accurate design and fabrication control. The residual roughness introduced by fabrication was taken into account in optical modeling and was a further contributing factor in plasmon localization, increasing the sensitivity and selectivity of the sensors. This methodology developed for breast cancer detection can be considered a general strategy that is applicable to various pathologies and other chemical analytical cases where complex mixtures have to be resolved in their constitutive components.
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Affiliation(s)
- Maria Laura Coluccio
- Bio-Nanotechnology and Engineering for Medicine (BIONEM), Department of Experimental and Clinical Medicine, University of Magna Graecia Viale Europa, Germaneto, Catanzaro 88100, Italy
| | - Francesco Gentile
- Bio-Nanotechnology and Engineering for Medicine (BIONEM), Department of Experimental and Clinical Medicine, University of Magna Graecia Viale Europa, Germaneto, Catanzaro 88100, Italy
- Department of Electrical Engineering and Information Technology, University of Naples, Naples 80125, Italy
| | - Gobind Das
- Physical Sciences and Engineering (PSE) and Biological and Environment Science and Engineering Divisions (BESE), King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Annalisa Nicastri
- Bio-Nanotechnology and Engineering for Medicine (BIONEM), Department of Experimental and Clinical Medicine, University of Magna Graecia Viale Europa, Germaneto, Catanzaro 88100, Italy
| | - Angela Mena Perri
- Bio-Nanotechnology and Engineering for Medicine (BIONEM), Department of Experimental and Clinical Medicine, University of Magna Graecia Viale Europa, Germaneto, Catanzaro 88100, Italy
| | - Patrizio Candeloro
- Bio-Nanotechnology and Engineering for Medicine (BIONEM), Department of Experimental and Clinical Medicine, University of Magna Graecia Viale Europa, Germaneto, Catanzaro 88100, Italy
| | - Gerardo Perozziello
- Bio-Nanotechnology and Engineering for Medicine (BIONEM), Department of Experimental and Clinical Medicine, University of Magna Graecia Viale Europa, Germaneto, Catanzaro 88100, Italy
| | | | - Juan Sebastian Totero Gongora
- PRIMALIGHT, Electrical Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Salma Alrasheed
- Physical Sciences and Engineering (PSE) and Biological and Environment Science and Engineering Divisions (BESE), King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Andrea Fratalocchi
- PRIMALIGHT, Electrical Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Tania Limongi
- Physical Sciences and Engineering (PSE) and Biological and Environment Science and Engineering Divisions (BESE), King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Giovanni Cuda
- Bio-Nanotechnology and Engineering for Medicine (BIONEM), Department of Experimental and Clinical Medicine, University of Magna Graecia Viale Europa, Germaneto, Catanzaro 88100, Italy
| | - Enzo Di Fabrizio
- Bio-Nanotechnology and Engineering for Medicine (BIONEM), Department of Experimental and Clinical Medicine, University of Magna Graecia Viale Europa, Germaneto, Catanzaro 88100, Italy
- Physical Sciences and Engineering (PSE) and Biological and Environment Science and Engineering Divisions (BESE), King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
- Corresponding author. E-mail:
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115
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Feng L, Li N, Li Y, Wang J, Gao M, Wang W, Chen J. Cell cycle-dependent inhibition of 53BP1 signaling by BRCA1. Cell Discov 2015; 1:15019. [PMID: 27462418 PMCID: PMC4860855 DOI: 10.1038/celldisc.2015.19] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 05/25/2015] [Indexed: 02/07/2023] Open
Abstract
DNA damage response mediator protein 53BP1 is a key regulator of non-homologous end-joining (NHEJ) repair. 53BP1 protects DNA broken ends from resection by recruiting two downstream factors, RIF1 (RAP1-interacting factor 1) and PTIP (Pax transactivation domain-interacting protein), to double-stranded breaks (DSBs) via ATM (ataxia telangiectasia mutated)-mediated 53BP1 phosphorylation, and competes with BRCA1-mediated homologous recombination (HR) repair in G1 phase. In contrast, BRCA1 antagonizes 53BP1-direct NHEJ repair in S/G2 phases. We and others have found that BRCA1 prevents the translocation of RIF1 to DSBs in S/G2 phases; however, the underlying mechanism remains unclear. Here we show that efficient ATM-dependent 53BP1 phosphorylation is restricted to the G1 phase of the cell cycle, as a consequence RIF1 and PTIP accumulation at DSB sites only occur in G1 phase. Mechanistically, both BRCT and RING domains of BRCA1 are required for the inhibition of 53BP1 phosphorylation in S and G2 phases. Thus, our findings reveal how BRCA1 antagonizes 53BP1 signaling to ensure that HR repair is the dominant repair pathway in S/G2 phases.
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Affiliation(s)
- Lin Feng
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA; State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-Sen University Cancer Center, Guangzhou, China
| | - Nan Li
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center , Houston, TX, USA
| | - Yujing Li
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA; State Key Laboratory for Biocontrol and Key Laboratory of Gene Engineering of Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jiadong Wang
- Institute of Systems Biomedicine, Medical Isotopes Research Center, School of Basic Medical Sciences, Peking University , Beijing, China
| | - Min Gao
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center , Houston, TX, USA
| | - Wenqi Wang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center , Houston, TX, USA
| | - Junjie Chen
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center , Houston, TX, USA
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116
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Alagoz M, Katsuki Y, Ogiwara H, Ogi T, Shibata A, Kakarougkas A, Jeggo P. SETDB1, HP1 and SUV39 promote repositioning of 53BP1 to extend resection during homologous recombination in G2 cells. Nucleic Acids Res 2015. [PMID: 26206670 PMCID: PMC4652757 DOI: 10.1093/nar/gkv722] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Recent studies have shown that homologous recombination (HR) requires chromatin repression as well as relaxation at DNA double strand breaks (DSBs). HP1 and SUV39H1/2 are repressive factors essential for HR. Here, we identify SETDB1 as an additional compacting factor promoting HR. Depletion of HP1, SUV39, SETDB1 or BRCA1 confer identical phenotypes. The repressive factors, like BRCA1, are dispensable for the initiation of resection but promote the extension step causing diminished RPA or RAD51 foci and HR in irradiated G2 cells. Depletion of the compacting factors does not inhibit BRCA1 recruitment but at 8 h post IR, BRCA1 foci are smaller and aberrantly positioned compared to control cells. BRCA1 promotes 53BP1 repositioning to the periphery of enlarged foci and formation of a devoid core with BRCA1 becoming enlarged and localized internally to 53BP1. Depletion of the compacting factors precludes these changes at irradiation-induced foci. Thus, the repressive factors are required for BRCA1 function in promoting the repositioning of 53BP1 during HR. Additionally, depletion of these repressive factors in undamaged cells causes diminished sister chromatid association at centromeric sequences. We propose a model for how these findings may be functionally linked.
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Affiliation(s)
- Meryem Alagoz
- University of Sussex Genome Damage and Stability Centre, East Sussex, BN19RQ, UK
| | - Yoko Katsuki
- University of Sussex Genome Damage and Stability Centre, East Sussex, BN19RQ, UK
| | - Hideaki Ogiwara
- Division of Genome Biology, National Cancer Centre Japan Research Institute, Tokyo, 104-0045, Japan
| | - Tomoo Ogi
- Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, 852-8523, Japan
| | - Atsushi Shibata
- University of Sussex Genome Damage and Stability Centre, East Sussex, BN19RQ, UK
| | - Andreas Kakarougkas
- University of Sussex Genome Damage and Stability Centre, East Sussex, BN19RQ, UK Department of Biology, School of Sciences and Engineering, The American University in Cairo, New Cairo, 11835, Egypt
| | - Penny Jeggo
- University of Sussex Genome Damage and Stability Centre, East Sussex, BN19RQ, UK
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117
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Abstract
The BRCA1 tumor suppressor protein is a central constituent of several distinct macromolecular protein complexes that execute homology-directed DNA damage repair and cell cycle checkpoints. Recent years have borne witness to an exciting phase of discovery at the basic molecular level for how this network of DNA repair proteins acts to maintain genome stability and suppress cancer. The clinical dividends of this investment are now being realized with the approval of first-in-class BRCA-targeted therapies for ovarian cancer and identification of molecular events that determine responsiveness to these agents. Further delineation of the basic science underlying BRCA network function holds promise to maximally exploit genome instability for hereditary and sporadic cancer therapy.
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Affiliation(s)
- Qinqin Jiang
- Departments of Cancer Biology and Pathology, Abramson Family Cancer Research Institute, and Basser Research Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Roger A Greenberg
- Departments of Cancer Biology and Pathology, Abramson Family Cancer Research Institute, and Basser Research Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104.
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118
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Abstract
DNA double-strand breaks (DSBs) in cells can undergo nucleolytic degradation to generate long 3' single-stranded DNA tails. This process is termed DNA end resection, and its occurrence effectively commits to break repair via homologous recombination, which entails the acquisition of genetic information from an intact, homologous donor DNA sequence. Recent advances, prompted by the identification of the nucleases that catalyze resection, have revealed intricate layers of functional redundancy, interconnectedness, and regulation. Here, we review the current state of the field with an emphasis on the major questions that remain to be answered. Topics addressed will include how resection initiates via the introduction of an endonucleolytic incision close to the break end, the molecular mechanism of the conserved MRE11 complex in conjunction with Sae2/CtIP within such a model, the role of BRCA1 and 53BP1 in regulating resection initiation in mammalian cells, the influence of chromatin in the resection process, and potential roles of novel factors.
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Affiliation(s)
- James M Daley
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA.
| | - Hengyao Niu
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, IN 47405, USA
| | - Adam S Miller
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Patrick Sung
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
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119
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Prakash R, Zhang Y, Feng W, Jasin M. Homologous recombination and human health: the roles of BRCA1, BRCA2, and associated proteins. Cold Spring Harb Perspect Biol 2015; 7:a016600. [PMID: 25833843 DOI: 10.1101/cshperspect.a016600] [Citation(s) in RCA: 608] [Impact Index Per Article: 60.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Homologous recombination (HR) is a major pathway for the repair of DNA double-strand breaks in mammalian cells, the defining step of which is homologous strand exchange directed by the RAD51 protein. The physiological importance of HR is underscored by the observation of genomic instability in HR-deficient cells and, importantly, the association of cancer predisposition and developmental defects with mutations in HR genes. The tumor suppressors BRCA1 and BRCA2, key players at different stages of HR, are frequently mutated in familial breast and ovarian cancers. Other HR proteins, including PALB2 and RAD51 paralogs, have also been identified as tumor suppressors. This review summarizes recent findings on BRCA1, BRCA2, and associated proteins involved in human disease with an emphasis on their molecular roles and interactions.
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Affiliation(s)
- Rohit Prakash
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Yu Zhang
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Weiran Feng
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065 Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Maria Jasin
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065 Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York 10065
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120
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Brown JS, Jackson SP. Ubiquitylation, neddylation and the DNA damage response. Open Biol 2015; 5:150018. [PMID: 25833379 PMCID: PMC4422126 DOI: 10.1098/rsob.150018] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 03/09/2015] [Indexed: 12/19/2022] Open
Abstract
Failure of accurate DNA damage sensing and repair mechanisms manifests as a variety of human diseases, including neurodegenerative disorders, immunodeficiency, infertility and cancer. The accuracy and efficiency of DNA damage detection and repair, collectively termed the DNA damage response (DDR), requires the recruitment and subsequent post-translational modification (PTM) of a complex network of proteins. Ubiquitin and the ubiquitin-like protein (UBL) SUMO have established roles in regulating the cellular response to DNA double-strand breaks (DSBs). A role for other UBLs, such as NEDD8, is also now emerging. This article provides an overview of the DDR, discusses our current understanding of the process and function of PTM by ubiquitin and NEDD8, and reviews the literature surrounding the role of ubiquitylation and neddylation in DNA repair processes, focusing particularly on DNA DSB repair.
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Affiliation(s)
- Jessica S Brown
- The Wellcome Trust and Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
| | - Stephen P Jackson
- The Wellcome Trust and Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
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121
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Obrist F, Manic G, Kroemer G, Vitale I, Galluzzi L. Trial Watch: Proteasomal inhibitors for anticancer therapy. Mol Cell Oncol 2015; 2:e974463. [PMID: 27308423 PMCID: PMC4904962 DOI: 10.4161/23723556.2014.974463] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Revised: 09/15/2014] [Accepted: 09/17/2014] [Indexed: 01/12/2023]
Abstract
The so-called "ubiquitin-proteasome system" (UPS) is a multicomponent molecular apparatus that catalyzes the covalent attachment of several copies of the small protein ubiquitin to other proteins that are generally (but not always) destined to proteasomal degradation. This enzymatic cascade is crucial for the maintenance of intracellular protein homeostasis (both in physiological conditions and in the course of adaptive stress responses), and regulates a wide array of signaling pathways. In line with this notion, defects in the UPS have been associated with aging as well as with several pathological conditions including cardiac, neurodegenerative, and neoplastic disorders. As transformed cells often experience a constant state of stress (as a result of the hyperactivation of oncogenic signaling pathways and/or adverse microenvironmental conditions), their survival and proliferation are highly dependent on the integrity of the UPS. This rationale has driven an intense wave of preclinical and clinical investigation culminating in 2003 with the approval of the proteasomal inhibitor bortezomib by the US Food and Drug Administration for use in multiple myeloma patients. Another proteasomal inhibitor, carfilzomib, is now licensed by international regulatory agencies for use in multiple myeloma patients, and the approved indications for bortezomib have been extended to mantle cell lymphoma. This said, the clinical activity of bortezomib and carfilzomib is often limited by off-target effects, innate/acquired resistance, and the absence of validated predictive biomarkers. Moreover, the antineoplastic activity of proteasome inhibitors against solid tumors is poor. In this Trial Watch we discuss the contribution of the UPS to oncogenesis and tumor progression and summarize the design and/or results of recent clinical studies evaluating the therapeutic profile of proteasome inhibitors in cancer patients.
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Affiliation(s)
- Florine Obrist
- Université Paris-Sud/Paris XI; Le Kremlin-Bicêtre, France
- INSERM, U1138; Paris, France
- Equipe 11 labelisée par la Ligue Nationale contre le Cancer, Center de Recherche des Cordeliers; Paris, France
- Gustave Roussy Cancer Campus; Villejuif, France
| | | | - Guido Kroemer
- INSERM, U1138; Paris, France
- Equipe 11 labelisée par la Ligue Nationale contre le Cancer, Center de Recherche des Cordeliers; Paris, France
- Université Paris Descartes/Paris V; Sorbonne Paris Cité; Paris, France
- Pôle de Biologie, Hôpital Européen Georges Pompidou; Paris, France
- Metabolomics and Cell Biology Platforms; Gustave Roussy Cancer Campus; Villejuif, France
| | - Ilio Vitale
- Regina Elena National Cancer Institute; Rome, Italy
- Department of Biology, University of Rome “Tor Vergata”
| | - Lorenzo Galluzzi
- INSERM, U1138; Paris, France
- Equipe 11 labelisée par la Ligue Nationale contre le Cancer, Center de Recherche des Cordeliers; Paris, France
- Gustave Roussy Cancer Campus; Villejuif, France
- Université Paris Descartes/Paris V; Sorbonne Paris Cité; Paris, France
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122
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Massively Parallel Functional Analysis of BRCA1 RING Domain Variants. Genetics 2015; 200:413-22. [PMID: 25823446 DOI: 10.1534/genetics.115.175802] [Citation(s) in RCA: 210] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 03/01/2015] [Indexed: 11/18/2022] Open
Abstract
Interpreting variants of uncertain significance (VUS) is a central challenge in medical genetics. One approach is to experimentally measure the functional consequences of VUS, but to date this approach has been post hoc and low throughput. Here we use massively parallel assays to measure the effects of nearly 2000 missense substitutions in the RING domain of BRCA1 on its E3 ubiquitin ligase activity and its binding to the BARD1 RING domain. From the resulting scores, we generate a model to predict the capacities of full-length BRCA1 variants to support homology-directed DNA repair, the essential role of BRCA1 in tumor suppression, and show that it outperforms widely used biological-effect prediction algorithms. We envision that massively parallel functional assays may facilitate the prospective interpretation of variants observed in clinical sequencing.
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123
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Wu Q, Jubb H, Blundell TL. Phosphopeptide interactions with BRCA1 BRCT domains: More than just a motif. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 117:143-148. [PMID: 25701377 PMCID: PMC4728184 DOI: 10.1016/j.pbiomolbio.2015.02.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Revised: 01/05/2015] [Accepted: 02/10/2015] [Indexed: 01/15/2023]
Abstract
BRCA1 BRCT domains function as phosphoprotein-binding modules for recognition of the phosphorylated protein-sequence motif pSXXF. While the motif interaction interface provides strong anchor points for binding, protein regions outside the motif have recently been found to be important for binding affinity. In this review, we compare the available structural data for BRCA1 BRCT domains in complex with phosphopeptides in order to gain a more complete understanding of the interaction between phosphopeptides and BRCA1-BRCT domains.
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Affiliation(s)
- Qian Wu
- Department of Biochemistry, 80 Tennis Court Road, University of Cambridge, CB2 1GA, Cambridge, United Kingdom.
| | - Harry Jubb
- Department of Biochemistry, 80 Tennis Court Road, University of Cambridge, CB2 1GA, Cambridge, United Kingdom
| | - Tom L Blundell
- Department of Biochemistry, 80 Tennis Court Road, University of Cambridge, CB2 1GA, Cambridge, United Kingdom
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124
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Savage KI, Harkin DP. BRCA1, a 'complex' protein involved in the maintenance of genomic stability. FEBS J 2014; 282:630-46. [PMID: 25400280 DOI: 10.1111/febs.13150] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 11/10/2014] [Accepted: 11/13/2014] [Indexed: 12/15/2022]
Abstract
BRCA1 is a major breast and ovarian cancer susceptibility gene, with mutations in this gene predisposing women to a very high risk of developing breast and ovarian tumours. BRCA1 primarily functions to maintain genomic stability via critical roles in DNA repair, cell cycle checkpoint control, transcriptional regulation, apoptosis and mRNA splicing. As a result, BRCA1 mutations often result in defective DNA repair, genomic instability and sensitivity to DNA damaging agents. BRCA1 carries out these different functions through its ability to interact, and form complexes with, a vast array of proteins involved in multiple cellular processes, all of which are considered to contribute to its function as a tumour suppressor. This review discusses and highlights recent research into the functions of BRCA1-related protein complexes and their roles in maintaining genomic stability and tumour suppression.
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Affiliation(s)
- Kienan I Savage
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, UK
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125
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Abstract
In 2007, three scientists, Drs. Mario R. Capecchi, Martin J. Evans, and Oliver Smithies, received the Nobel Prize in Physiology or Medicine for their contributions of introducing specific gene modifications into mice. This technology, commonly referred to as gene targeting or knockout, has proven to be a powerful means for precisely manipulating the mammalian genome and has generated great impacts on virtually all phases of mammalian biology and basic biomedical research. Of note, germline mutations of many genes, especially tumor suppressors, often result in lethality during embryonic development or at developmental stages before tumor formation. This obstacle has been effectively overcome by the use of conditional knockout technology in conjunction with Cre-LoxP- or Flp-Frt-mediated temporal and/or spatial systems to generate genetic switches for precise DNA recombination. Currently, numerous conditional knockout mouse models have been successfully generated and applied in studying tumor initiation, progression, and metastasis. This review summarizes some conditional mutant mouse models that are widely used in cancer research and our understanding of the possible mechanisms underlying tumorigenesis.
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Affiliation(s)
- Chu-Xia Deng
- Genetics of Development and Disease Branch, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
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126
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Bai F, Chan HL, Scott A, Smith MD, Fan C, Herschkowitz JI, Perou CM, Livingstone AS, Robbins DJ, Capobianco AJ, Pei XH. BRCA1 suppresses epithelial-to-mesenchymal transition and stem cell dedifferentiation during mammary and tumor development. Cancer Res 2014; 74:6161-72. [PMID: 25239453 DOI: 10.1158/0008-5472.can-14-1119] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BRCA1 mutation carriers are predisposed to developing basal-like breast cancers with high metastasis and poor prognosis. Yet, how BRCA1 suppresses formation of basal-like breast cancers is still obscure. Deletion of p18(Ink4c) (p18), an inhibitor of CDK4 and CDK6, functionally inactivates the RB pathway, stimulates mammary luminal stem cell (LSC) proliferation, and leads to spontaneous luminal tumor development. Alternately, germline mutation of Brca1 shifts the fate of luminal cells to cause luminal-to-basal mammary tumor transformation. Here, we report that disrupting Brca1 by either germline or epithelium-specific mutation in p18-deficient mice activates epithelial-to-mesenchymal transition (EMT) and induces dedifferentiation of LSCs, which associate closely with expansion of basal and cancer stem cells and formation of basal-like tumors. Mechanistically, BRCA1 bound to the TWIST promoter, suppressing its activity and inhibiting EMT in mammary tumor cells. In human luminal cancer cells, BRCA1 silencing was sufficient to activate TWIST and EMT and increase tumor formation. In parallel, TWIST expression and EMT features correlated inversely with BRCA1 expression in human breast cancers. Together, our findings showed that BRCA1 suppressed TWIST and EMT, inhibited LSC dedifferentiation, and repressed expansion of basal stem cells and basal-like tumors. Thus, our work offers the first genetic evidence that Brca1 directly suppresses EMT and LSC dedifferentiation during breast tumorigenesis.
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Affiliation(s)
- Feng Bai
- Molecular Oncology Program, Department of Surgery and
| | - Ho Lam Chan
- Molecular Oncology Program, Department of Surgery and
| | | | - Matthew D Smith
- Lineberger Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Cheng Fan
- Lineberger Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Jason I Herschkowitz
- Lineberger Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Charles M Perou
- Lineberger Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | | | - David J Robbins
- Molecular Oncology Program, Department of Surgery and Sylvester Cancer Center, Miller School of Medicine, University of Miami, Miami, Florida
| | - Anthony J Capobianco
- Molecular Oncology Program, Department of Surgery and Sylvester Cancer Center, Miller School of Medicine, University of Miami, Miami, Florida
| | - Xin-Hai Pei
- Molecular Oncology Program, Department of Surgery and Sylvester Cancer Center, Miller School of Medicine, University of Miami, Miami, Florida.
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127
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Kalb R, Mallery DL, Larkin C, Huang JTJ, Hiom K. BRCA1 is a histone-H2A-specific ubiquitin ligase. Cell Rep 2014; 8:999-1005. [PMID: 25131202 PMCID: PMC4382519 DOI: 10.1016/j.celrep.2014.07.025] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 03/18/2014] [Accepted: 07/16/2014] [Indexed: 11/03/2022] Open
Abstract
The RING domain proteins BRCA1 and BARD1 comprise a heterodimeric ubiquitin (E3) ligase that is required for the accumulation of ubiquitin conjugates at sites of DNA damage and for silencing at DNA satellite repeat regions. Despite its links to chromatin, the substrate and underlying function of the BRCA1/BARD1 ubiquitin ligase remain unclear. Here, we show that BRCA1/BARD1 specifically ubiquitylates histone H2A in its C-terminal tail on lysines 127 and 129 in vitro and in vivo. The specificity for K127-129 is acquired only when H2A is within a nucleosomal context. Moreover, site-specific targeting of the BRCA1/BARD1 RING domains to chromatin is sufficient for H2Aub foci formation in vivo. Our data establish BRCA1/BARD1 as a histone-H2A-specific E3 ligase, helping to explain its localization and activities on chromatin in cells.
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Affiliation(s)
- Reinhard Kalb
- Division of Protein Nucleic Acid Chemistry, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK; Department of Chromatin Research, MPI of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Donna L Mallery
- Division of Protein Nucleic Acid Chemistry, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Conor Larkin
- Division of Cancer Research, Medical Research Institute, Ninewells Hospital & Medical School, Dundee DD1 9SY, Scotland
| | - Jeffrey T J Huang
- Biomarker and Drug Analysis Core Facility, Medical Research Institute, Ninewells Hospital & Medical School, Dundee DD1 9SY, Scotland
| | - Kevin Hiom
- Division of Protein Nucleic Acid Chemistry, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK; Division of Cancer Research, Medical Research Institute, Ninewells Hospital & Medical School, Dundee DD1 9SY, Scotland.
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128
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Castillo A, Paul A, Sun B, Huang TH, Wang Y, Yazinski SA, Tyler J, Li L, You MJ, Zou L, Yao J, Wang B. The BRCA1-interacting protein Abraxas is required for genomic stability and tumor suppression. Cell Rep 2014; 8:807-17. [PMID: 25066119 DOI: 10.1016/j.celrep.2014.06.050] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 05/18/2014] [Accepted: 06/25/2014] [Indexed: 11/16/2022] Open
Abstract
Germline mutations of BRCA1 confer hereditary susceptibility to breast and ovarian cancer. However, somatic mutation of BRCA1 is infrequent in sporadic breast cancers. The BRCA1 protein C terminus (BRCT) domains interact with multiple proteins and are required for BRCA1's tumor-suppressor function. In this study, we demonstrated that Abraxas, a BRCA1 BRCT domain-interacting protein, plays a role in tumor suppression. Abraxas exerts its function through binding to BRCA1 to regulate DNA repair and maintain genome stability. Both homozygous and heterozygous Abraxas knockout mice exhibited decreased survival and increased tumor incidence. The gene encoding Abraxas suffers from gene copy loss and somatic mutations in multiple human cancers including breast, ovarian, and endometrial cancers, suggesting that mutation and loss of function of Abraxas may contribute to tumor development in human patients.
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Affiliation(s)
- Andy Castillo
- Department of Genetics, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Atanu Paul
- Department of Genetics, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA; Genes and Development Program, The University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Baohua Sun
- Department of Genetics, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Ting Hsiang Huang
- Department of Biochemistry and Molecular Biology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA; Genes and Development Program, The University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Yucai Wang
- Department of Experimental Radiation Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Stephanie A Yazinski
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Jessica Tyler
- Department of Biochemistry and Molecular Biology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Lei Li
- Department of Experimental Radiation Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA
| | - M James You
- Department of Hematopathology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Lee Zou
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Jun Yao
- Department of Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Bin Wang
- Department of Genetics, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA; Genes and Development Program, The University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030, USA.
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129
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Polato F, Callen E, Wong N, Faryabi R, Bunting S, Chen HT, Kozak M, Kruhlak MJ, Reczek CR, Lee WH, Ludwig T, Baer R, Feigenbaum L, Jackson S, Nussenzweig A. CtIP-mediated resection is essential for viability and can operate independently of BRCA1. ACTA ACUST UNITED AC 2014; 211:1027-36. [PMID: 24842372 PMCID: PMC4042650 DOI: 10.1084/jem.20131939] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In contrast to BRCA1, CtIP has indispensable roles in promoting resection and embryonic development. Homologous recombination (HR) is initiated by DNA end resection, a process in which stretches of single-strand DNA (ssDNA) are generated and used for homology search. Factors implicated in resection include nucleases MRE11, EXO1, and DNA2, which process DNA ends into 3′ ssDNA overhangs; helicases such as BLM, which unwind DNA; and other proteins such as BRCA1 and CtIP whose functions remain unclear. CDK-mediated phosphorylation of CtIP on T847 is required to promote resection, whereas CDK-dependent phosphorylation of CtIP-S327 is required for interaction with BRCA1. Here, we provide evidence that CtIP functions independently of BRCA1 in promoting DSB end resection. First, using mouse models expressing S327A or T847A mutant CtIP as a sole species, and B cells deficient in CtIP, we show that loss of the CtIP-BRCA1 interaction does not detectably affect resection, maintenance of genomic stability or viability, whereas T847 is essential for these functions. Second, although loss of 53BP1 rescues the embryonic lethality and HR defects in BRCA1-deficient mice, it does not restore viability or genome integrity in CtIP−/− mice. Third, the increased resection afforded by loss of 53BP1 and the rescue of BRCA1-deficiency depend on CtIP but not EXO1. Finally, the sensitivity of BRCA1-deficient cells to poly ADP ribose polymerase (PARP) inhibition is partially rescued by the phospho-mimicking mutant CtIP (CtIP-T847E). Thus, in contrast to BRCA1, CtIP has indispensable roles in promoting resection and embryonic development.
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Affiliation(s)
- Federica Polato
- Laboratory of Genome Integrity, Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Elsa Callen
- Laboratory of Genome Integrity, Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Nancy Wong
- Laboratory of Genome Integrity, Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Robert Faryabi
- Laboratory of Genome Integrity, Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Samuel Bunting
- Laboratory of Genome Integrity, Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Hua-Tang Chen
- Laboratory of Genome Integrity, Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Marina Kozak
- Laboratory of Genome Integrity, Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Michael J Kruhlak
- Laboratory of Genome Integrity, Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Colleen R Reczek
- Institute for Cancer Genetics, Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032
| | - Wen-Hwa Lee
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, CA 92697
| | - Thomas Ludwig
- Ohio State University Wexner Medical Center, Columbus, OH 43210
| | - Richard Baer
- Institute for Cancer Genetics, Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032
| | - Lionel Feigenbaum
- Science Applications International Corporation-Frederick National Cancer Institute-Frederick Cancer Research and Development Center, Frederick, MD 21704
| | - Stephen Jackson
- The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, England, UK The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, England, UK The Wellcome Trust Sanger Institute, Hinxton CB10 1SA, England, UK
| | - André Nussenzweig
- Laboratory of Genome Integrity, Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
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130
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Abstract
Since DNA double-strand breaks (DSBs) contribute to the genomic instability that drives cancer development, DSB repair pathways serve as important mechanisms for tumor suppression. Thus, genetic lesions, such as BRCA1 and BRCA2 mutations, that disrupt DSB repair are often associated with cancer susceptibility. In addition, recent evidence suggests that DSB "mis-repair", in which DSBs are resolved by an inappropriate repair pathway, can also promote genomic instability and presumably tumorigenesis. This notion has gained currency from recent cancer genome sequencing studies which have uncovered numerous chromosomal rearrangements harboring pathological DNA repair signatures. In this perspective, we discuss the factors that regulate DSB repair pathway choice and their consequences for genome stability and cancer.
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Affiliation(s)
- Tomas Aparicio
- Institute for Cancer Genetics & Department of Genetics and Development, Columbia University Medical Center, New York, NY, USA
| | - Richard Baer
- Institute for Cancer Genetics & Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Jean Gautier
- Institute for Cancer Genetics & Department of Genetics and Development, Columbia University Medical Center, New York, NY, USA.
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131
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Christou CM, Hadjisavvas A, Kyratzi M, Flouri C, Neophytou I, Anastasiadou V, Loizidou MA, Kyriacou K. The BRCA1 variant p.Ser36Tyr abrogates BRCA1 protein function and potentially confers a moderate risk of breast cancer. PLoS One 2014; 9:e93400. [PMID: 24695549 PMCID: PMC3973689 DOI: 10.1371/journal.pone.0093400] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 03/04/2014] [Indexed: 11/30/2022] Open
Abstract
The identification of variants of unknown clinical significance (VUS) in the BRCA1 gene complicates genetic counselling and causes additional anxiety to carriers. In silico approaches currently used for VUS pathogenicity assessment are predictive and often produce conflicting data. Furthermore, functional assays are either domain or function specific, thus they do not examine the entire spectrum of BRCA1 functions and interpretation of individual assay results can be misleading. PolyPhen algorithm predicted that the BRCA1 p.Ser36Tyr VUS identified in the Cypriot population was damaging, whereas Align-GVGD predicted that it was possibly of no significance. In addition the BRCA1 p.Ser36Tyr variant was found to be associated with increased risk (OR = 3.47, 95% CI 1.13-10.67, P = 0.02) in a single case-control series of 1174 cases and 1109 controls. We describe a cellular system for examining the function of exogenous full-length BRCA1 and for classifying VUS. We achieved strong protein expression of full-length BRCA1 in transiently transfected HEK293T cells. The p.Ser36Tyr VUS exhibited low protein expression similar to the known pathogenic variant p.Cys61Gly. Co-precipitation analysis further demonstrated that it has a reduced ability to interact with BARD1. Further, co-precipitation analysis of nuclear and cytosolic extracts as well as immunofluorescence studies showed that a high proportion of the p.Ser36Tyr variant is withheld in the cytoplasm contrary to wild type protein. In addition the ability of p.Ser36Tyr to co-localize with conjugated ubiquitin foci in the nuclei of S-phase synchronized cells following genotoxic stress with hydroxyurea is impaired at more pronounced levels than that of the p.Cys61Gly pathogenic variant. The p.Ser36Tyr variant demonstrates abrogated function, and based on epidemiological, genetic, and clinical data we conclude that the p.Ser36Tyr variant is probably associated with a moderate breast cancer risk.
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Affiliation(s)
- Charita M. Christou
- The Cyprus Institute of Neurology and Genetics, Department of Electron Microscopy/Molecular Pathology, Nicosia, Cyprus
| | - Andreas Hadjisavvas
- The Cyprus Institute of Neurology and Genetics, Department of Electron Microscopy/Molecular Pathology, Nicosia, Cyprus
| | - Maria Kyratzi
- The Cyprus Institute of Neurology and Genetics, Department of Electron Microscopy/Molecular Pathology, Nicosia, Cyprus
- The University of Cyprus, Department of Biological Sciences, Nicosia, Cyprus
| | - Christina Flouri
- The Cyprus Institute of Neurology and Genetics, Department of Electron Microscopy/Molecular Pathology, Nicosia, Cyprus
| | - Ioanna Neophytou
- The Cyprus Institute of Neurology and Genetics, Department of Electron Microscopy/Molecular Pathology, Nicosia, Cyprus
| | - Violetta Anastasiadou
- The Cyprus Institute of Neurology and Genetics, Department of Clinical Genetics, Nicosia, Cyprus
| | - Maria A. Loizidou
- The Cyprus Institute of Neurology and Genetics, Department of Electron Microscopy/Molecular Pathology, Nicosia, Cyprus
| | - Kyriacos Kyriacou
- The Cyprus Institute of Neurology and Genetics, Department of Electron Microscopy/Molecular Pathology, Nicosia, Cyprus
- * E-mail:
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132
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Yi YW, Kang HJ, Bae I. BRCA1 and Oxidative Stress. Cancers (Basel) 2014; 6:771-95. [PMID: 24704793 PMCID: PMC4074803 DOI: 10.3390/cancers6020771] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 03/20/2014] [Accepted: 03/24/2014] [Indexed: 01/07/2023] Open
Abstract
The breast cancer susceptibility gene 1 (BRCA1) has been well established as a tumor suppressor and functions primarily by maintaining genome integrity. Genome stability is compromised when cells are exposed to oxidative stress. Increasing evidence suggests that BRCA1 regulates oxidative stress and this may be another mechanism in preventing carcinogenesis in normal cells. Oxidative stress caused by reactive oxygen species (ROS) is implicated in carcinogenesis and is used strategically to treat human cancer. Thus, it is essential to understand the function of BRCA1 in oxidative stress regulation. In this review, we briefly summarize BRCA1's many binding partners and mechanisms, and discuss data supporting the function of BRCA1 in oxidative stress regulation. Finally, we consider its significance in prevention and/or treatment of BRCA1-related cancers.
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Affiliation(s)
- Yong Weon Yi
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA.
| | - Hyo Jin Kang
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA.
| | - Insoo Bae
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA.
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133
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Abstract
Germline mutations in BRCA1 and BRCA2 predispose to common human malignancies, most notably tumors of the breast and ovaries. The proteins encoded by these genes have been implicated in a plethora of biochemical interactions and biological functions, confounding attempts to coherently explain how their inactivation promotes carcinogenesis. Here, I argue that tumor suppression by BRCA1 and BRCA2 originates from their fundamental role in controlling the assembly and activity of macromolecular complexes that monitor chromosome duplication, maintenance, and segregation across the cell cycle. A tumor-suppressive role for the BRCA proteins as "chromosome custodians" helps to explain the clinical features of cancer susceptibility after their inactivation, provides foundations for the rational therapy of BRCA-deficient cancers, and offers general insights into the mechanisms opposing early steps in human carcinogenesis.
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Affiliation(s)
- Ashok R Venkitaraman
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
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134
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Chailleux C, Aymard F, Caron P, Daburon V, Courilleau C, Canitrot Y, Legube G, Trouche D. Quantifying DNA double-strand breaks induced by site-specific endonucleases in living cells by ligation-mediated purification. Nat Protoc 2014; 9:517-28. [PMID: 24504477 DOI: 10.1038/nprot.2014.031] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Recent advances in our understanding of the management and repair of DNA double-strand breaks (DSBs) rely on the study of targeted DSBs that have been induced in living cells by the controlled activity of site-specific endonucleases, usually recombinant restriction enzymes. Here we describe a protocol for quantifying these endonuclease-induced DSBs; this quantification is essential to an interpretation of how DSBs are managed and repaired. A biotinylated double-stranded oligonucleotide is ligated to enzyme-cleaved genomic DNA, allowing the purification of the cleaved DNA on streptavidin beads. The extent of cleavage is then quantified either by quantitative PCR (qPCR) at a given site or at multiple sites by genome-wide techniques (e.g., microarrays or high-throughput sequencing). This technique, named ligation-mediated purification, can be performed in 2 d. It is more accurate and sensitive than existing alternative methods, and it is compatible with genome-wide analysis. It allows the amount of endonuclease-mediated breaks to be precisely compared between two conditions or across the genome, thereby giving insight into the influence of a given factor or of various chromatin contexts on local repair parameters.
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Affiliation(s)
- Catherine Chailleux
- 1] Université de Toulouse, Université Paul Sabatier, Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération (LBCMCP), Toulouse, France. [2] Centre National de la Recherche Scientifique, LBCMCP, Toulouse, France
| | - François Aymard
- 1] Université de Toulouse, Université Paul Sabatier, Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération (LBCMCP), Toulouse, France. [2] Centre National de la Recherche Scientifique, LBCMCP, Toulouse, France
| | - Pierre Caron
- 1] Université de Toulouse, Université Paul Sabatier, Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération (LBCMCP), Toulouse, France. [2] Centre National de la Recherche Scientifique, LBCMCP, Toulouse, France
| | - Virginie Daburon
- 1] Université de Toulouse, Université Paul Sabatier, Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération (LBCMCP), Toulouse, France. [2] Centre National de la Recherche Scientifique, LBCMCP, Toulouse, France
| | - Céline Courilleau
- 1] Université de Toulouse, Université Paul Sabatier, Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération (LBCMCP), Toulouse, France. [2] Centre National de la Recherche Scientifique, LBCMCP, Toulouse, France
| | - Yvan Canitrot
- 1] Université de Toulouse, Université Paul Sabatier, Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération (LBCMCP), Toulouse, France. [2] Centre National de la Recherche Scientifique, LBCMCP, Toulouse, France
| | - Gaëlle Legube
- 1] Université de Toulouse, Université Paul Sabatier, Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération (LBCMCP), Toulouse, France. [2] Centre National de la Recherche Scientifique, LBCMCP, Toulouse, France. [3]
| | - Didier Trouche
- 1] Université de Toulouse, Université Paul Sabatier, Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération (LBCMCP), Toulouse, France. [2] Centre National de la Recherche Scientifique, LBCMCP, Toulouse, France. [3]
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135
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Multifactorial likelihood assessment of BRCA1 and BRCA2 missense variants confirms that BRCA1:c.122A>G(p.His41Arg) is a pathogenic mutation. PLoS One 2014; 9:e86836. [PMID: 24489791 PMCID: PMC3904950 DOI: 10.1371/journal.pone.0086836] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 12/13/2013] [Indexed: 11/22/2022] Open
Abstract
Rare exonic, non-truncating variants in known cancer susceptibility genes such as BRCA1 and BRCA2 are problematic for genetic counseling and clinical management of relevant families. This study used multifactorial likelihood analysis and/or bioinformatically-directed mRNA assays to assess pathogenicity of 19 BRCA1 or BRCA2 variants identified following patient referral to clinical genetic services. Two variants were considered to be pathogenic (Class 5). BRCA1:c.4484G> C(p.Arg1495Thr) was shown to result in aberrant mRNA transcripts predicted to encode truncated proteins. The BRCA1:c.122A>G(p.His41Arg) RING-domain variant was found from multifactorial likelihood analysis to have a posterior probability of pathogenicity of 0.995, a result consistent with existing protein functional assay data indicating lost BARD1 binding and ubiquitin ligase activity. Of the remaining variants, seven were determined to be not clinically significant (Class 1), nine were likely not pathogenic (Class 2), and one was uncertain (Class 3).These results have implications for genetic counseling and medical management of families carrying these specific variants. They also provide additional multifactorial likelihood variant classifications as reference to evaluate the sensitivity and specificity of bioinformatic prediction tools and/or functional assay data in future studies.
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136
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Abstract
In this issue of Molecular Cell, Chiba and colleagues (Matsuzawa et al., 2014) identify Obg-like ATPase 1 (OLA1) as an additional member of the BRCA1/BARD1/γ-tubulin complex that is critically involved in centrosome amplification and microtubule aster formation.
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Affiliation(s)
- Valenti Gomez
- UCL Cancer Institute, University College London, London WC1E 6BT, UK
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137
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Abstract
Germline mutations of human breast cancer-associated gene 1 (BRCA1) predispose women to breast and ovarian cancers. In mice, over 20 distinct mutations, including null, hypomorphic, isoform, conditional, and point mutations, have been created to study functions of Brca1 in mammary development and tumorigenesis. Analyses using these mutant mice have yielded an enormous amount of information that greatly facilitates our understanding of the gender- and tissue-specific tumor suppressor functions of BRCA1, as well as enriches our insights into applying these preclinical models of disease to breast cancer research. Here, we review features of these mutant mice and their applications to cancer prevention and therapeutic treatment.
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138
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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: 92] [Impact Index Per Article: 7.7] [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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139
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Bouwman P, Jonkers J. Molecular pathways: how can BRCA-mutated tumors become resistant to PARP inhibitors? Clin Cancer Res 2013; 20:540-7. [PMID: 24270682 DOI: 10.1158/1078-0432.ccr-13-0225] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PARP inhibition is synthetic lethal with defective DNA repair via homologous recombination. Phase I and II clinical trials show that PARP inhibitors are effective at well-tolerated doses and have antitumor activity for BRCA1- and BRCA2-associated cancers. However, not all patients respond equally well and tumors may eventually become resistant. Thus far, the only resistance mechanism that has been found in human tumors is genetic reversion that corrects or bypasses the original BRCA1- or BRCA2-inactivating mutation. However, data from fundamental and preclinical research suggest that resistance to PARP inhibitors may be induced by additional mechanisms involving hypomorphic activity of mutant BRCA1 alleles, upregulation of drug efflux pumps, and rewiring of the DNA damage response. Preclinical models will be instrumental to develop methods for adequate patient stratification, as well as treatment strategies that prevent or counteract resistance to PARP inhibitors.
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Affiliation(s)
- Peter Bouwman
- Authors' Affiliation: Division of Molecular Pathology and Cancer Genomics Centre, The Netherlands Cancer Institute, Amsterdam, the Netherlands
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140
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Liu X, Ladias JAA. Structural basis for the BRCA1 BRCT interaction with the proteins ATRIP and BAAT1. Biochemistry 2013; 52:7618-27. [PMID: 24073851 DOI: 10.1021/bi400714v] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The breast and ovarian cancer susceptibility protein 1 (BRCA1) plays a central role in DNA damage response (DDR). Two tandem BRCA1 C-terminal (BRCT) domains interact with several proteins that function in DDR and contain the generally accepted motif pS-X-X-F (pS denoting phosphoserine and X any amino acid), including the ATR-interacting protein (ATRIP) and the BRCA1-associated protein required for ATM activation-1 (BAAT1). The crystal structures of the BRCA1 BRCTs bound to the phosphopeptides ATRIP (235-PEACpSPQFG-243) and BAAT1 (266-VARpSPVFSS-274) were determined at 1.75 Å and 2.2 Å resolution, respectively. The pSer and Phe(+3) anchor the phosphopeptides into the BRCT binding groove, with adjacent peptide residues contributing to the interaction. In the BRCA1-ATRIP structure, Gln(+2) is accommodated through a conformational change of the BRCA1 E1698 side chain. Importantly, isothermal titration calorimetry experiments showed that the size and charge of the side chains at peptide positions +1 and +2 contribute significantly to the BRCA1 BRCT-peptide binding affinity. In particular, the Asp(+1) and Glu(+2) in the human CDC27 peptide 816-HAAEpSDEF-823 abrogate the interaction with the BRCA1 BRCTs due in large part to electrostatic repulsion between Glu(+2) and E1698, indicating a preference of these domains for specific side chains at positions +1 and +2. These results emphasize the need for a systematic assessment of the contribution of the peptide residues surrounding pSer and Phe(+3) to the binding affinity and specificity of the BRCA1 BRCTs in order to elucidate the molecular mechanisms underlying the hierarchy of target selection by these versatile domains during DDR and tumorigenesis.
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Affiliation(s)
- Xuying Liu
- Molecular Medicine Laboratory and Macromolecular Crystallography Unit, Department of Medicine, Harvard Medical School , Boston Massachusetts 02215, United States
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141
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Filipponi D, Muller J, Emelyanov A, Bulavin DV. Wip1 controls global heterochromatin silencing via ATM/BRCA1-dependent DNA methylation. Cancer Cell 2013; 24:528-41. [PMID: 24135283 DOI: 10.1016/j.ccr.2013.08.022] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 06/05/2013] [Accepted: 08/23/2013] [Indexed: 12/25/2022]
Abstract
Wip1 phosphatase is emerging as an important regulator of tumorigenesis, but no unifying mechanistic network has been proposed. We found that Wip1 plays a key role in the transcriptional regulation of heterochromatin-associated DNA sequences. Wip1 was required for epigenetic remodeling of repetitive DNA elements through regulation of BRCA1 interaction with HP1, the recruitment of DNA methyltransferases, and subsequent DNA methylation. Attenuation of ATM, in turn, reversed heterochromatin methylation. This mechanism was critical for the recruitment of the AID cytidine deaminase, and Wip1 levels strongly correlated with C-to-T substitutions and a total mutation load in primary breast cancers. We propose that Wip1 plays an important role in the regulation of global heterochromatin silencing and thus is critical in maintaining genome integrity.
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Affiliation(s)
- Doria Filipponi
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore 138673
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142
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Guglielmi C, Cerri I, Evangelista M, Collavoli A, Tancredi M, Aretini P, Caligo MA. Identification of two novel BRCA1-partner genes in the DNA double-strand break repair pathway. Breast Cancer Res Treat 2013; 141:515-22. [PMID: 24104880 DOI: 10.1007/s10549-013-2705-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 09/16/2013] [Indexed: 01/03/2023]
Abstract
M1775R and A1789T are two missense variants located within the BRCT domains of BRCA1 gene. The M1775R is a known deleterious variant, while the A1789T is an unclassified variant that has been analyzed and classified as probably deleterious for the first time by our group. In a previous study, we described the expression profile of HeLa G1 cells transfected with the two variants and we found that they altered molecular mechanisms critical for cell proliferation and genome integrity. Considering that the mutations in the BRCA1 C terminus (BRCT) domains are associated to a phenotype with an altered ability in the DNA double-strand break repair, we chose three of the genes previously identified, EEF1E1, MRE11A, and OBFC2B, to be tested for an homologous recombination (HR) in vitro assay. For our purpose, we performed a gene expression knockdown by siRNA transfection in HeLa cells, containing an integrated recombination substrate (hprtDRGFP), for each of the target genes included BRCA1. The knockdown of BRCA1, OBFC2B, MRE11A, and EEF1E1 reduces the HR rate, respectively, of 97.6, 28.6, 41.8, and 42.3 % compared to cells transfected with a scrambled negative control duplex and all these differences are statistically significant (P < 0.05; Kruskal-Wallis test). Finally, we analyzed the effect of target gene depletion both on HR that on cell survival after DNA-damage induction by ionizing radiation. The clonogenic assay showed that the down-regulation of the target genes reduced the cell survival, but the effect on the HR, is not evident. Only the BRCA1-siRNA confirmed the inhibition effect on HR. Overall these results confirmed the involvement of MRE11A in the HR pathway and identified two new genes, OBFC2B and EEF1E1, which according to these data and the knowledge obtained from literature, might be involved in BRCA1-pathway.
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Affiliation(s)
- Chiara Guglielmi
- Section of Genetic Oncology, University Hospital and University of Pisa, Pisa, Italy
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143
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Soyombo AA, Wu Y, Kolski L, Rios JJ, Rakheja D, Chen A, Kehler J, Hampel H, Coughran A, Ross TS. Analysis of induced pluripotent stem cells from a BRCA1 mutant family. Stem Cell Reports 2013; 1:336-49. [PMID: 24319668 PMCID: PMC3849250 DOI: 10.1016/j.stemcr.2013.08.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 08/14/2013] [Accepted: 08/15/2013] [Indexed: 02/09/2023] Open
Abstract
Understanding BRCA1 mutant cancers is hampered by difficulties in obtaining primary cells from patients. We therefore generated and characterized 24 induced pluripotent stem cell (iPSC) lines from fibroblasts of eight individuals from a BRCA1 5382insC mutant family. All BRCA1 5382insC heterozygous fibroblasts, iPSCs, and teratomas maintained equivalent expression of both wild-type and mutant BRCA1 transcripts. Although no difference in differentiation capacity was observed between BRCA1 wild-type and mutant iPSCs, there was elevated protein kinase C-theta (PKC-theta) in BRCA1 mutant iPSCs. Cancer cell lines with BRCA1 mutations and hormone-receptor-negative breast cancers also displayed elevated PKC-theta. Genome sequencing of the 24 iPSC lines showed a similar frequency of reprogramming-associated de novo mutations in BRCA1 mutant and wild-type iPSCs. These data indicate that iPSC lines can be derived from BRCA1 mutant fibroblasts to study the effects of the mutation on gene expression and genome stability.
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Affiliation(s)
- Abigail A Soyombo
- Department of Internal Medicine, High Risk Cancer Genetics Program, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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144
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Stabilization of mutant BRCA1 protein confers PARP inhibitor and platinum resistance. Proc Natl Acad Sci U S A 2013; 110:17041-6. [PMID: 24085845 DOI: 10.1073/pnas.1305170110] [Citation(s) in RCA: 216] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Breast Cancer Type 1 Susceptibility Protein (BRCA1)-deficient cells have compromised DNA repair and are sensitive to poly(ADP-ribose) polymerase (PARP) inhibitors. Despite initial responses, the development of resistance limits clinical efficacy. Mutations in the BRCA C-terminal (BRCT) domain of BRCA1 frequently create protein products unable to fold that are subject to protease-mediated degradation. Here, we show HSP90-mediated stabilization of a BRCT domain mutant BRCA1 protein under PARP inhibitor selection pressure. The stabilized mutant BRCA1 protein interacted with PALB2-BRCA2-RAD51, was essential for RAD51 focus formation, and conferred PARP inhibitor as well as cisplatin resistance. Treatment of resistant cells with the HSP90 inhibitor 17-dimethylaminoethylamino-17-demethoxygeldanamycin reduced mutant BRCA1 protein levels and restored their sensitivity to PARP inhibition. Resistant cells also acquired a TP53BP1 mutation that facilitated DNA end resection in the absence of a BRCA1 protein capable of binding CtIP. Finally, concomitant increased mutant BRCA1 and decreased 53BP1 protein expression occur in clinical samples of BRCA1-mutated recurrent ovarian carcinomas that have developed resistance to platinum. These results provide evidence for a two-event mechanism by which BRCA1-mutant tumors acquire anticancer therapy resistance.
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145
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Abstract
Domchek and colleagues provide a case report of a 28-year-old woman with congenital abnormalities, inherited ovarian cancer, and carboplatin hypersensitivity. Interestingly, the woman had validated germline mutations in both BRCA1 alleles. These findings further implicate BRCA1 in the Fanconi anemia/BRCA pathway and have important implications for BRCA1 genetic testing.
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Affiliation(s)
- Alan D D'Andrea
- Departments of Radiation Oncology and Pediatrics, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02215, USA.
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146
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Kakarougkas A, Ismail A, Katsuki Y, Freire R, Shibata A, Jeggo PA. Co-operation of BRCA1 and POH1 relieves the barriers posed by 53BP1 and RAP80 to resection. Nucleic Acids Res 2013; 41:10298-311. [PMID: 24013561 PMCID: PMC3905848 DOI: 10.1093/nar/gkt802] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
In G2 phase cells, DNA double-strand break repair switches from DNA non-homologous end-joining to homologous recombination. This switch demands the promotion of resection. We examine the changes in 53BP1 and RAP80 ionizing radiation induced foci (IRIF) in G2 phase, as these are factors that restrict resection. We observed a 2-fold increase in the volume of 53BP1 foci by 8 h, which is not seen in G1 cells. Additionally, an IRIF core devoid of 53BP1 arises where RPA foci form, with BRCA1 IRIF forming between 53BP1 and replication protein A (RPA). Ubiquitin chains assessed using α-FK2 antibodies are similarly repositioned. Repositioning of all these components requires BRCA1’s BRCT but not the ring finger domain. 53BP1, RAP80 and ubiquitin chains are enlarged following POH1 depletion by small interfering RNA, but a devoid core does not form and RPA foci formation is impaired. Co-depletion of POH1 and RAP80, BRCC36 or ABRAXAS allows establishment of the 53BP1 and ubiquitin chain-devoid core. Thus, the barriers posed by 53BP1 and RAP80 are relieved by BRCA1 and POH1, respectively. Analysis of combined depletions shows that these represent distinct but interfacing barriers to promote loss of ubiquitin chains in the IRIF core, which is required for subsequent resection. We propose a model whereby BRCA1 impacts on 53BP1 to allow access of POH1 to RAP80. POH1-dependent removal of RAP80 within the IRIF core enables degradation of ubiquitin chains, which promotes loss of 53BP1. Thus, POH1 represents a novel component regulating the switch from non-homologous end-joining to homologous recombination.
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Affiliation(s)
- Andreas Kakarougkas
- Genome Damage and Stability Centre, DNA double Strand Break Repair Laboratory, University of Sussex, Brighton BN1 9 RQ, UK and Unidad de Investigación, Hospital Universitario de Canarias, Instituto de Tecnologías Biomédicas, Ofra s/n, 38320 La Laguna, Tenerife, Spain
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147
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Opportunities and hurdles in the treatment of BRCA1-related breast cancer. Oncogene 2013; 33:3753-63. [PMID: 23955079 DOI: 10.1038/onc.2013.329] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 06/13/2013] [Accepted: 06/21/2013] [Indexed: 12/11/2022]
Abstract
BRCA1 functions as a classical tumor suppressor in breast and ovarian cancer. While the role of BRCA1 in homology-directed repair of DNA double-strand breaks contributes to its tumor suppressive activity, it also renders BRCA1-deficient cells highly sensitive to DNA-damaging agents. Although BRCA1 deficiency is therefore considered to be an attractive therapeutic target, re-activation of BRCA1 by secondary mutations has been shown to cause therapy resistance. In this review, we will assess the role of BRCA1 in both hereditary and sporadic breast cancer and discuss how different functionalities of the BRCA1 protein can contribute to its tumor suppressor function. In addition, we will discuss how this knowledge on BRCA1 function can help to overcome the hurdles encountered in the clinic and improve current treatment strategies for patients with BRCA1-related breast cancer.
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148
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Reczek CR, Szabolcs M, Stark JM, Ludwig T, Baer R. The interaction between CtIP and BRCA1 is not essential for resection-mediated DNA repair or tumor suppression. ACTA ACUST UNITED AC 2013; 201:693-707. [PMID: 23712259 PMCID: PMC3664708 DOI: 10.1083/jcb.201302145] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In mammalian cells, the phospho-dependent interaction between BRCA1 and CtIP is not required for homology-directed DNA repair or tumor suppression. The CtIP protein facilitates homology-directed repair (HDR) of double-strand DNA breaks (DSBs) by initiating DNA resection, a process in which DSB ends are converted into 3′-ssDNA overhangs. The BRCA1 tumor suppressor, which interacts with CtIP in a phospho-dependent manner, has also been implicated in DSB repair through the HDR pathway. It was recently reported that the BRCA1–CtIP interaction is essential for HDR in chicken DT40 cells. To examine the role of this interaction in mammalian cells, we generated cells and mice that express Ctip polypeptides (Ctip-S326A) that fail to bind BRCA1. Surprisingly, isogenic lines of Ctip-S326A mutant and wild-type cells displayed comparable levels of HDR function and chromosomal stability. Although Ctip-S326A mutant cells were modestly sensitive to topoisomerase inhibitors, mice expressing Ctip-S326A polypeptides developed normally and did not exhibit a predisposition to cancer. Thus, in mammals, the phospho-dependent BRCA1–CtIP interaction is not essential for HDR-mediated DSB repair or for tumor suppression.
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Affiliation(s)
- Colleen R Reczek
- Institute for Cancer Genetics, Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032, USA
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149
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BRCA1 promotes the ubiquitination of PCNA and recruitment of translesion polymerases in response to replication blockade. Proc Natl Acad Sci U S A 2013; 110:13558-63. [PMID: 23901102 DOI: 10.1073/pnas.1306534110] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Breast cancer gene 1 (BRCA1) deficient cells not only are hypersensitive to double-strand breaks but also are hypersensitive to UV irradiation and other agents that cause replication blockade; however, the molecular mechanisms behind these latter sensitivities are largely unknown. Here, we report that BRCA1 promotes cell survival by directly regulating the DNA damage tolerance pathway in response to agents that create cross-links in DNA. We show that BRCA1 not only promotes efficient mono- and polyubiquitination of proliferating cell nuclear antigen (PCNA) by regulating the recruitment of replication protein A, Rad18, and helicase-like transcription factor to chromatin but also directly recruits translesion polymerases, such as Polymerase eta and Rev1, to the lesions through protein-protein interactions. Our data suggest that BRCA1 plays a critical role in promoting translesion DNA synthesis as well as DNA template switching.
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150
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Bouwman P, van der Gulden H, van der Heijden I, Drost R, Klijn CN, Prasetyanti P, Pieterse M, Wientjens E, Seibler J, Hogervorst FBL, Jonkers J. A high-throughput functional complementation assay for classification of BRCA1 missense variants. Cancer Discov 2013; 3:1142-55. [PMID: 23867111 DOI: 10.1158/2159-8290.cd-13-0094] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
UNLABELLED Mutations in BRCA1 and BRCA2 account for the majority of hereditary breast and ovarian cancers, and therefore sequence analysis of both genes is routinely conducted in patients with early-onset breast cancer. Besides mutations that clearly abolish protein function or are known to increase cancer risk, a large number of sequence variants of uncertain significance (VUS) have been identified. Although several functional assays for BRCA1 VUSs have been described, thus far it has not been possible to conduct a high-throughput analysis in the context of the full-length protein. We have developed a relatively fast and easy cDNA-based functional assay to classify BRCA1 VUSs based on their ability to functionally complement BRCA1-deficient mouse embryonic stem cells. Using this assay, we have analyzed 74 unclassified BRCA1 missense mutants for which all predicted pathogenic variants are confined to the BRCA1 RING and BRCT domains. SIGNIFICANCE BRCA1 VUSs are frequently found in patients with hereditary breast or ovarian cancer and present a serious problem for clinical geneticists. This article describes the generation, validation, and application of a reliable high-throughput assay for the functional classification of BRCA1 sequence variants of uncertain significance.
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Affiliation(s)
- Peter Bouwman
- 1Division of Molecular Pathology and Cancer Genomics Centre and 2Department of Pathology, The Netherlands Cancer Institute Amsterdam, The Netherlands; and 3TaconicArtemis GmbH, Cologne, Germany
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