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Li S, Tang M, Xiong Y, Feng X, Wang C, Nie L, Huang M, Zhang H, Yin L, Zhu D, Yang C, Ma T, Chen J. Systematic investigation of BRCA1-A, -B, and -C complexes and their functions in DNA damage response and DNA repair. Oncogene 2024:10.1038/s41388-024-03108-y. [PMID: 39068216 DOI: 10.1038/s41388-024-03108-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 07/14/2024] [Accepted: 07/16/2024] [Indexed: 07/30/2024]
Abstract
BRCA1, a breast cancer susceptibility gene, has emerged as a central mediator that brings together multiple signaling complexes in response to DNA damage. The A, B, and C complexes of BRCA1, which are formed based on their phosphorylation-dependent interactions with the BRCA1-C-terminal domains, contribute to the roles of BRCA1 in DNA repair and cell cycle checkpoint control. However, their functions in DNA damage response remain to be fully appreciated. Specifically, there has been no systematic investigation of the roles of BRCA1-A, -B, and -C complexes in the regulation of BRCA1 localization and functions, in part because of cellular lethality associated with loss of CtIP protein, which is an essential component in BRCA1-C complex. To systematically investigate the functions of these complexes in DNA damage response, we depleted a key component in each of these complexes. We used the degradation tag system to inducibly deplete endogenous CtIP and obtained a series of RAP80/FANCJ/CtIP single-, double-, and triple-knockout cells. We showed that loss of BRCA1-B/FANCJ and BRCA1-C/CtIP, but not BRCA1-A/RAP80, resulted in reduced cell proliferation and increased sensitivity to DNA damage. BRCA1-C/CtIP and BRCA1-A/RAP80 were involved in BRCA1 recruitment to sites of DNA damage. However, BRCA1-A/RAP80 was not essential for damage-induced BRCA1 localization. Instead, RAP80/H2AX and CtIP have redundant roles in BRCA1 recruitment. Altogether, our systematic analysis uncovers functional differences between BRCA1-A, -B, and -C complexes and provides new insights into the roles of these BRCA1-associated protein complexes in DNA damage response and DNA repair.
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Affiliation(s)
- Siting Li
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Mengfan Tang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Department of Immunology, School of Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Yun Xiong
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Xu Feng
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Chao Wang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Litong Nie
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Min Huang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Huimin Zhang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Ling Yin
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Dandan Zhu
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Chang Yang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Tiantian Ma
- 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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2
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Chauhan AS, Jhujh SS, Stewart GS. E3 ligases: a ubiquitous link between DNA repair, DNA replication and human disease. Biochem J 2024; 481:923-944. [PMID: 38985307 DOI: 10.1042/bcj20240124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 05/20/2024] [Accepted: 05/24/2024] [Indexed: 07/11/2024]
Abstract
Maintenance of genome stability is of paramount importance for the survival of an organism. However, genomic integrity is constantly being challenged by various endogenous and exogenous processes that damage DNA. Therefore, cells are heavily reliant on DNA repair pathways that have evolved to deal with every type of genotoxic insult that threatens to compromise genome stability. Notably, inherited mutations in genes encoding proteins involved in these protective pathways trigger the onset of disease that is driven by chromosome instability e.g. neurodevelopmental abnormalities, neurodegeneration, premature ageing, immunodeficiency and cancer development. The ability of cells to regulate the recruitment of specific DNA repair proteins to sites of DNA damage is extremely complex but is primarily mediated by protein post-translational modifications (PTMs). Ubiquitylation is one such PTM, which controls genome stability by regulating protein localisation, protein turnover, protein-protein interactions and intra-cellular signalling. Over the past two decades, numerous ubiquitin (Ub) E3 ligases have been identified to play a crucial role not only in the initiation of DNA replication and DNA damage repair but also in the efficient termination of these processes. In this review, we discuss our current understanding of how different Ub E3 ligases (RNF168, TRAIP, HUWE1, TRIP12, FANCL, BRCA1, RFWD3) function to regulate DNA repair and replication and the pathological consequences arising from inheriting deleterious mutations that compromise the Ub-dependent DNA damage response.
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Affiliation(s)
- Anoop S Chauhan
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, U.K
| | - Satpal S Jhujh
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, U.K
| | - Grant S Stewart
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, U.K
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3
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Iqbal MJ, Kabeer A, Abbas Z, Siddiqui HA, Calina D, Sharifi-Rad J, Cho WC. Interplay of oxidative stress, cellular communication and signaling pathways in cancer. Cell Commun Signal 2024; 22:7. [PMID: 38167159 PMCID: PMC10763046 DOI: 10.1186/s12964-023-01398-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 11/14/2023] [Indexed: 01/05/2024] Open
Abstract
Cancer remains a significant global public health concern, with increasing incidence and mortality rates worldwide. Oxidative stress, characterized by the production of reactive oxygen species (ROS) within cells, plays a critical role in the development of cancer by affecting genomic stability and signaling pathways within the cellular microenvironment. Elevated levels of ROS disrupt cellular homeostasis and contribute to the loss of normal cellular functions, which are associated with the initiation and progression of various types of cancer. In this review, we have focused on elucidating the downstream signaling pathways that are influenced by oxidative stress and contribute to carcinogenesis. These pathways include p53, Keap1-NRF2, RB1, p21, APC, tumor suppressor genes, and cell type transitions. Dysregulation of these pathways can lead to uncontrolled cell growth, impaired DNA repair mechanisms, and evasion of cell death, all of which are hallmark features of cancer development. Therapeutic strategies aimed at targeting oxidative stress have emerged as a critical area of investigation for molecular biologists. The objective is to limit the response time of various types of cancer, including liver, breast, prostate, ovarian, and lung cancers. By modulating the redox balance and restoring cellular homeostasis, it may be possible to mitigate the damaging effects of oxidative stress and enhance the efficacy of cancer treatments. The development of targeted therapies and interventions that specifically address the impact of oxidative stress on cancer initiation and progression holds great promise in improving patient outcomes. These approaches may include antioxidant-based treatments, redox-modulating agents, and interventions that restore normal cellular function and signaling pathways affected by oxidative stress. In summary, understanding the role of oxidative stress in carcinogenesis and targeting this process through therapeutic interventions are of utmost importance in combating various types of cancer. Further research is needed to unravel the complex mechanisms underlying oxidative stress-related pathways and to develop effective strategies that can be translated into clinical applications for the management and treatment of cancer. Video Abstract.
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Affiliation(s)
| | - Ayesha Kabeer
- Department of Biotechnology, University of Sialkot, Sialkot, Punjab, Pakistan
- Institute of Biochemistry and Biotechnology, University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Zaighum Abbas
- Department of Biotechnology, University of Sialkot, Sialkot, Punjab, Pakistan
| | | | - Daniela Calina
- Department of Clinical Pharmacy, University of Medicine and Pharmacy of Craiova, 200349, Craiova, Romania.
| | | | - William C Cho
- Department of Clinical Oncology, Queen Elizabeth Hospital, Kowloon, Hong Kong.
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4
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Burdett H, Foglizzo M, Musgrove LJ, Kumar D, Clifford G, Campbell L, Heath GR, Zeqiraj E, Wilson M. BRCA1-BARD1 combines multiple chromatin recognition modules to bridge nascent nucleosomes. Nucleic Acids Res 2023; 51:11080-11103. [PMID: 37823591 PMCID: PMC10639053 DOI: 10.1093/nar/gkad793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 08/02/2023] [Accepted: 09/20/2023] [Indexed: 10/13/2023] Open
Abstract
Chromatin association of the BRCA1-BARD1 heterodimer is critical to promote homologous recombination repair of DNA double-strand breaks (DSBs) in S/G2. How the BRCA1-BARD1 complex interacts with chromatin that contains both damage induced histone H2A ubiquitin and inhibitory H4K20 methylation is not fully understood. We characterised BRCA1-BARD1 binding and enzymatic activity to an array of mono- and di-nucleosome substrates using biochemical, structural and single molecule imaging approaches. We found that the BRCA1-BARD1 complex preferentially interacts and modifies di-nucleosomes over mono-nucleosomes, allowing integration of H2A Lys-15 ubiquitylation signals with other chromatin modifications and features. Using high speed- atomic force microscopy (HS-AFM) to monitor how the BRCA1-BARD1 complex recognises chromatin in real time, we saw a highly dynamic complex that bridges two nucleosomes and associates with the DNA linker region. Bridging is aided by multivalent cross-nucleosome interactions that enhance BRCA1-BARD1 E3 ubiquitin ligase catalytic activity. Multivalent interactions across nucleosomes explain how BRCA1-BARD1 can recognise chromatin that retains partial di-methylation at H4 Lys-20 (H4K20me2), a parental histone mark that blocks BRCA1-BARD1 interaction with nucleosomes, to promote its enzymatic and DNA repair activities.
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Affiliation(s)
- Hayden Burdett
- Wellcome Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Kings Buildings, Mayfield Road, Edinburgh EH9 3JR, UK
| | - Martina Foglizzo
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Laura J Musgrove
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Dhananjay Kumar
- Wellcome Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Kings Buildings, Mayfield Road, Edinburgh EH9 3JR, UK
| | - Gillian Clifford
- Wellcome Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Kings Buildings, Mayfield Road, Edinburgh EH9 3JR, UK
| | - Lisa J Campbell
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - George R Heath
- Astbury Centre for Structural Molecular Biology, School of Physics & Astronomy and Biomedical Sciences, Faculty of Engineering & Physical Sciences and Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Elton Zeqiraj
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Marcus D Wilson
- Wellcome Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Kings Buildings, Mayfield Road, Edinburgh EH9 3JR, UK
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5
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Wu D, Huang H, Chen T, Gai X, Li Q, Wang C, Yao J, Liu Y, Cai S, Yu X. The BRCA1/BARD1 complex recognizes pre-ribosomal RNA to facilitate homologous recombination. Cell Discov 2023; 9:99. [PMID: 37789001 PMCID: PMC10547766 DOI: 10.1038/s41421-023-00590-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 07/16/2023] [Indexed: 10/05/2023] Open
Abstract
The BRCA1/BARD1 complex plays a key role in the repair of DNA double-strand breaks (DSBs) in both somatic cells and germ cells. However, the underlying molecular mechanism by which this complex mediates DSB repair is not fully understood. Here, we examined the XY body of male germ cells, where DSBs are accumulated. We show that the recruitment of the BRCA1/BARD1 complex to the unsynapsed axis of the XY body is mediated by pre-ribosomal RNA (pre-rRNA). Similarly, the BRCA1/BARD1 complex associates with pre-rRNA in somatic cells, which not only forms nuclear foci in response to DSBs, but also targets the BRCA1/BARD1 complex to DSBs. The interactions between the BRCT domains of the BRCA1/BARD1 complex and pre-rRNA induce liquid-liquid phase separations, which may be the molecular basis of DSB-induced nuclear foci formation of the BRCA1/BARD1 complex. Moreover, cancer-associated mutations in the BRCT domains of BRCA1 and BARD1 abolish their interactions with pre-rRNA. Pre-rRNA also mediates BRCA1-dependent homologous recombination, and suppression of pre-rRNA biogenesis sensitizes cells to PARP inhibitor treatment. Collectively, this study reveals that pre-rRNA is a functional partner of the BRCA1/BARD1 complex in the DSB repair.
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Affiliation(s)
- Duo Wu
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Huang Huang
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Tenglong Chen
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Xiaochen Gai
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Qilin Li
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Chunhui Wang
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Westlake Disease Modeling Lab, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
| | - Jia Yao
- The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yu Liu
- The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Shang Cai
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Westlake Disease Modeling Lab, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
| | - Xiaochun Yu
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China.
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China.
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China.
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6
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Zhong AX, Chen Y, Chen PL. BRCA1 the Versatile Defender: Molecular to Environmental Perspectives. Int J Mol Sci 2023; 24:14276. [PMID: 37762577 PMCID: PMC10532398 DOI: 10.3390/ijms241814276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 09/13/2023] [Accepted: 09/14/2023] [Indexed: 09/29/2023] Open
Abstract
The evolving history of BRCA1 research demonstrates the profound interconnectedness of a single protein within the web of crucial functions in human cells. Mutations in BRCA1, a tumor suppressor gene, have been linked to heightened breast and ovarian cancer risks. However, despite decades of extensive research, the mechanisms underlying BRCA1's contribution to tissue-specific tumor development remain elusive. Nevertheless, much of the BRCA1 protein's structure, function, and interactions has been elucidated. Individual regions of BRCA1 interact with numerous proteins to play roles in ubiquitination, transcription, cell checkpoints, and DNA damage repair. At a cellular scale, these BRCA1 functions coordinate tumor suppression, R-loop prevention, and cellular differentiation, all of which may contribute to BRCA1's role in cancer tissue specificity. As research on BRCA1 and breast cancer continues to evolve, it will become increasingly evident that modern materials such as Bisphenol A should be examined for their relationship with DNA stability, cancer incidence, and chemotherapy. Overall, this review offers a comprehensive understanding of BRCA1's many roles at a molecular, cellular, organismal, and environmental scale. We hope that the knowledge gathered here highlights both the necessity of BRCA1 research and the potential for novel strategies to prevent and treat cancer in individuals carrying BRCA1 mutations.
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Affiliation(s)
- Amy X. Zhong
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA;
| | - Yumay Chen
- Department of Medicine, Division of Endocrinology, University of California, Irvine, CA 92697, USA;
| | - Phang-Lang Chen
- Department of Biological Chemistry, University of California, Irvine, CA 92697, USA
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Peña-Guerrero J, Fernández-Rubio C, García-Sosa AT, Nguewa PA. BRCT Domains: Structure, Functions, and Implications in Disease-New Therapeutic Targets for Innovative Drug Discovery against Infections. Pharmaceutics 2023; 15:1839. [PMID: 37514027 PMCID: PMC10386641 DOI: 10.3390/pharmaceutics15071839] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/12/2023] [Accepted: 06/22/2023] [Indexed: 07/30/2023] Open
Abstract
The search for new therapeutic targets and their implications in drug development remains an emerging scientific topic. BRCT-bearing proteins are found in Archaea, Bacteria, Eukarya, and viruses. They are traditionally involved in DNA repair, recombination, and cell cycle control. To carry out these functions, BRCT domains are able to interact with DNA and proteins. Moreover, such domains are also implicated in several pathogenic processes and malignancies including breast, ovarian, and lung cancer. Although these domains exhibit moderately conserved folding, their sequences show very low conservation. Interestingly, sequence variations among species are considered positive traits in the search for suitable therapeutic targets, since non-specific drug interactions might be reduced. These main characteristics of BRCT, as well as its critical implications in key biological processes in the cell, have prompted the study of these domains as therapeutic targets. This review explores the possible roles of BRCT domains as therapeutic targets for drug discovery. We describe their common structural features and relevant interactions and pathways, as well as their implications in pathologic processes. Drugs commonly used to target these domains are also presented. Finally, based on their structures, we describe new drug design possibilities using modern and innovative techniques.
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Affiliation(s)
- José Peña-Guerrero
- ISTUN Institute of Tropical Health, Department of Microbiology and Parasitology, University of Navarra, IdiSNA (Navarra Institute for Health Research), E-31008 Pamplona, Navarra, Spain
| | - Celia Fernández-Rubio
- ISTUN Institute of Tropical Health, Department of Microbiology and Parasitology, University of Navarra, IdiSNA (Navarra Institute for Health Research), E-31008 Pamplona, Navarra, Spain
| | - Alfonso T García-Sosa
- Chair of Molecular Technology, Institute of Chemistry, University of Tartu, Ravila 14a, 50411 Tartu, Estonia
| | - Paul A Nguewa
- ISTUN Institute of Tropical Health, Department of Microbiology and Parasitology, University of Navarra, IdiSNA (Navarra Institute for Health Research), E-31008 Pamplona, Navarra, Spain
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8
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Sachsenweger J, Jansche R, Merk T, Heitmeir B, Deniz M, Faust U, Roggia C, Tzschach A, Schroeder C, Riess A, Pospiech H, Peltoketo H, Pylkäs K, Winqvist R, Wiesmüller L. ABRAXAS1 orchestrates BRCA1 activities to counter genome destabilizing repair pathways-lessons from breast cancer patients. Cell Death Dis 2023; 14:328. [PMID: 37198153 DOI: 10.1038/s41419-023-05845-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 04/27/2023] [Accepted: 05/02/2023] [Indexed: 05/19/2023]
Abstract
It has been well-established that mutations in BRCA1 and BRCA2, compromising functions in DNA double-strand break repair (DSBR), confer hereditary breast and ovarian cancer risk. Importantly, mutations in these genes explain only a minor fraction of the hereditary risk and of the subset of DSBR deficient tumors. Our screening efforts identified two truncating germline mutations in the gene encoding the BRCA1 complex partner ABRAXAS1 in German early-onset breast cancer patients. To unravel the molecular mechanisms triggering carcinogenesis in these carriers of heterozygous mutations, we examined DSBR functions in patient-derived lymphoblastoid cells (LCLs) and in genetically manipulated mammary epithelial cells. By use of these strategies we were able to demonstrate that these truncating ABRAXAS1 mutations exerted dominant effects on BRCA1 functions. Interestingly, we did not observe haploinsufficiency regarding homologous recombination (HR) proficiency (reporter assay, RAD51-foci, PARP-inhibitor sensitivity) in mutation carriers. However, the balance was shifted to use of mutagenic DSBR-pathways. The dominant effect of truncated ABRAXAS1 devoid of the C-terminal BRCA1 binding site can be explained by retention of the N-terminal interaction sites for other BRCA1-A complex partners like RAP80. In this case BRCA1 was channeled from the BRCA1-A to the BRCA1-C complex, which induced single-strand annealing (SSA). Further truncation, additionally deleting the coiled-coil region of ABRAXAS1, unleashed excessive DNA damage responses (DDRs) de-repressing multiple DSBR-pathways including SSA and non-homologous end-joining (NHEJ). Our data reveal de-repression of low-fidelity repair activities as a common feature of cells from patients with heterozygous mutations in genes encoding BRCA1 and its complex partners.
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Affiliation(s)
- Juliane Sachsenweger
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany
- Laboratory of Cancer Genetics and Tumor Biology, Translational Medicine Research Unit, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Rebecca Jansche
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany
| | - Tatjana Merk
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany
| | - Benedikt Heitmeir
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany
| | - Miriam Deniz
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany
| | - Ulrike Faust
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Cristiana Roggia
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Andreas Tzschach
- Institute of Human Genetics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Christopher Schroeder
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Angelika Riess
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Helmut Pospiech
- Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Hellevi Peltoketo
- Laboratory of Cancer Genetics and Tumor Biology, Translational Medicine Research Unit, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Katri Pylkäs
- Laboratory of Cancer Genetics and Tumor Biology, Translational Medicine Research Unit, Biocenter Oulu, University of Oulu, Oulu, Finland
- Laboratory of Cancer Genetics and Tumor Biology, Northern Finland Laboratory Centre, Oulu, Finland
| | - Robert Winqvist
- Laboratory of Cancer Genetics and Tumor Biology, Translational Medicine Research Unit, Biocenter Oulu, University of Oulu, Oulu, Finland
- Laboratory of Cancer Genetics and Tumor Biology, Northern Finland Laboratory Centre, Oulu, Finland
| | - Lisa Wiesmüller
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany.
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9
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The BRCA1 BRCT promotes antisense RNA production and double-stranded RNA formation to suppress ribosomal R-loops. Proc Natl Acad Sci U S A 2022; 119:e2217542119. [PMID: 36490315 PMCID: PMC9897471 DOI: 10.1073/pnas.2217542119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
R-loops, or RNA:DNA hybrids, can induce DNA damage, which requires DNA repair factors including breast cancer type 1 susceptibility protein (BRCA1) to restore genomic integrity. To date, several pathogenic mutations have been found within the tandem BRCA1 carboxyl-terminal (BRCT) domains that mediate BRCA1 interactions with proteins and DNA in response to DNA damage. Here, we describe a nonrepair role of BRCA1 BRCT in suppressing ribosomal R-loops via two mechanisms. Through its RNA binding and annealing activities, BRCA1 BRCT facilitates the formation of double-stranded RNA between ribosomal RNA (rRNA) and antisense-rRNA (as-rRNA), hereby minimizing rRNA hybridization to ribosomal DNA to form R-loops. BRCA1 BRCT also promotes RNA polymerase I-dependent transcription of as-rRNA to enhance double-stranded rRNA (ds-rRNA) formation. In addition, BRCA1 BRCT-mediated as-rRNA production restricts rRNA maturation in unperturbed cells. Hence, impairing as-rRNA transcription and ds-rRNA formation due to BRCA1 BRCT deficiency deregulates rRNA processing and increases ribosomal R-loops and DNA breaks. Our results link ribosomal biogenesis dysfunction to BRCA1-associated genomic instability.
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Park D, Gharghabi M, Reczek CR, Plow R, Yungvirt C, Aldaz CM, Huebner K. Wwox Binding to the Murine Brca1-BRCT Domain Regulates Timing of Brip1 and CtIP Phospho-Protein Interactions with This Domain at DNA Double-Strand Breaks, and Repair Pathway Choice. Int J Mol Sci 2022; 23:ijms23073729. [PMID: 35409089 PMCID: PMC8999063 DOI: 10.3390/ijms23073729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 03/21/2022] [Accepted: 03/24/2022] [Indexed: 11/16/2022] Open
Abstract
Wwox-deficient human cells show elevated homologous recombination, leading to resistance to killing by double-strand break-inducing agents. Human Wwox binds to the Brca1 981-PPLF-984 Wwox-binding motif, likely blocking the pChk2 phosphorylation site at Brca1-S988. This phosphorylation site is conserved across mammalian species; the PPLF motif is conserved in primates but not in rodents. We now show that murine Wwox does not bind Brca1 near the conserved mouse Brca1 phospho-S971 site, leaving it open for Chk2 phosphorylation and Brca1 activation. Instead, murine Wwox binds to Brca1 through its BRCT domain, where pAbraxas, pBrip1, and pCtIP, of the A, B, and C binding complexes, interact to regulate double-strand break repair pathway response. In Wwox-deficient mouse cells, the Brca1-BRCT domain is thus accessible for immediate binding of these phospho-proteins. We confirm elevated homologous recombination in Wwox-silenced murine cells, as in human cells. Wwox-deficient murine cells showed increased ionizing radiation-induced Abraxas, Brca1, and CtIP foci and long resected single-strand DNA, early after ionizing radiation. Wwox deletion increased the basal level of Brca1-CtIP interaction and the expression level of the MRN-CtIP protein complex, key players in end-resection, and facilitated Brca1 release from foci. Inhibition of phospho-Chk2 phosphorylation of Brca1-S971 delays the end-resection; the delay of premature end-resection by combining Chk2 inhibition with ionizing radiation or carboplatin treatment restored ionizing radiation and platinum sensitivity in Wwox-deficient murine cells, as in human cells, supporting the use of murine in vitro and in vivo models in preclinical cancer treatment research.
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Affiliation(s)
- Dongju Park
- Department of Cancer Biology and Genetics, The Comprehensive Cancer Center, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; (M.G.); (R.P.); (C.Y.)
- Correspondence: (D.P.); (K.H.); Tel.: +1-614-685-9124 (D.P.); +1-614-292-4850 (K.H.)
| | - Mehdi Gharghabi
- Department of Cancer Biology and Genetics, The Comprehensive Cancer Center, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; (M.G.); (R.P.); (C.Y.)
- Department of Outcomes and Translational Sciences, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA
| | - Colleen R. Reczek
- Department of Pathology & Cell Biology, Columbia University Irving Medical Center, Columbia University, New York, NY 10032, USA;
| | - Rebecca Plow
- Department of Cancer Biology and Genetics, The Comprehensive Cancer Center, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; (M.G.); (R.P.); (C.Y.)
| | - Charles Yungvirt
- Department of Cancer Biology and Genetics, The Comprehensive Cancer Center, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; (M.G.); (R.P.); (C.Y.)
| | - C. Marcelo Aldaz
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, 1881 East Road, Houston, TX 77054, USA;
| | - Kay Huebner
- Department of Cancer Biology and Genetics, The Comprehensive Cancer Center, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; (M.G.); (R.P.); (C.Y.)
- Correspondence: (D.P.); (K.H.); Tel.: +1-614-685-9124 (D.P.); +1-614-292-4850 (K.H.)
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11
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Fu X, Tan W, Song Q, Pei H, Li J. BRCA1 and Breast Cancer: Molecular Mechanisms and Therapeutic Strategies. Front Cell Dev Biol 2022; 10:813457. [PMID: 35300412 PMCID: PMC8921524 DOI: 10.3389/fcell.2022.813457] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 01/18/2022] [Indexed: 11/13/2022] Open
Abstract
Breast cancer susceptibility gene 1 (BRCA1) is a tumor suppressor gene, which is mainly involved in the repair of DNA damage, cell cycle regulation, maintenance of genome stability, and other important physiological processes. Mutations or defects in the BRCA1 gene significantly increase the risk of breast, ovarian, prostate, and other cancers in carriers. In this review, we summarized the molecular functions and regulation of BRCA1 and discussed recent insights into the detection and treatment of BRCA1 mutated breast cancer.
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Affiliation(s)
- Xiaoyu Fu
- Department of Breast and Thyroid Surgery, Renmin Hospital of Wuhan University, Wuhan, China.,Cancer Center, Renmin Hospital of Wuhan University, Wuhan, China
| | - Wei Tan
- Department of Biochemistry and Molecular Medicine, The George Washington University School of Medicine and Health Sciences, Washington, DC, United States
| | - Qibin Song
- Cancer Center, Renmin Hospital of Wuhan University, Wuhan, China
| | - Huadong Pei
- Department of Oncology, Georgetown Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, United States
| | - Juanjuan Li
- Department of Breast and Thyroid Surgery, Renmin Hospital of Wuhan University, Wuhan, China.,Cancer Center, Renmin Hospital of Wuhan University, Wuhan, China
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12
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Bolck HA, Przetocka S, Meier R, von Aesch C, Zurfluh C, Hänggi K, Spegg V, Altmeyer M, Stebler M, Nørrelykke SF, Horvath P, Sartori AA, Porro A. RNAi Screening Uncovers a Synthetic Sick Interaction between CtIP and the BARD1 Tumor Suppressor. Cells 2022; 11:643. [PMID: 35203293 PMCID: PMC8870135 DOI: 10.3390/cells11040643] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 02/07/2022] [Accepted: 02/10/2022] [Indexed: 11/23/2022] Open
Abstract
Human CtIP is best known for its role in DNA end resection to initiate DNA double-strand break repair by homologous recombination. Recently, CtIP has also been shown to protect reversed replication forks from nucleolytic degradation upon DNA replication stress. However, still little is known about the DNA damage response (DDR) networks that preserve genome integrity and sustain cell survival in the context of CtIP insufficiency. Here, to reveal such potential buffering relationships, we screened a DDR siRNA library in CtIP-deficient cells to identify candidate genes that induce synthetic sickness/lethality (SSL). Our analyses unveil a negative genetic interaction between CtIP and BARD1, the heterodimeric binding partner of BRCA1. We found that simultaneous disruption of CtIP and BARD1 triggers enhanced apoptosis due to persistent replication stress-induced DNA lesions giving rise to chromosomal abnormalities. Moreover, we observed that the genetic interaction between CtIP and BARD1 occurs independently of the BRCA1-BARD1 complex formation and might be, therefore, therapeutical relevant for the treatment of BRCA-defective tumors.
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Affiliation(s)
- Hella A. Bolck
- Institute of Molecular Cancer Research, University of Zurich, 8057 Zurich, Switzerland; (H.A.B.); (S.P.); (C.v.A.); (C.Z.); (K.H.)
- Institute of Pathology and Molecular Pathology, University Hospital Zurich, 8091 Zurich, Switzerland
| | - Sara Przetocka
- Institute of Molecular Cancer Research, University of Zurich, 8057 Zurich, Switzerland; (H.A.B.); (S.P.); (C.v.A.); (C.Z.); (K.H.)
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Roger Meier
- Scientific Center for Optical and Electron Microscopy (ScopeM), ETH Zurich, 8093 Zurich, Switzerland; (R.M.); (M.S.); (S.F.N.)
| | - Christine von Aesch
- Institute of Molecular Cancer Research, University of Zurich, 8057 Zurich, Switzerland; (H.A.B.); (S.P.); (C.v.A.); (C.Z.); (K.H.)
| | - Christina Zurfluh
- Institute of Molecular Cancer Research, University of Zurich, 8057 Zurich, Switzerland; (H.A.B.); (S.P.); (C.v.A.); (C.Z.); (K.H.)
| | - Kay Hänggi
- Institute of Molecular Cancer Research, University of Zurich, 8057 Zurich, Switzerland; (H.A.B.); (S.P.); (C.v.A.); (C.Z.); (K.H.)
- Department of Immunology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL 33612, USA
| | - Vincent Spegg
- Department of Molecular Mechanisms of Disease, University of Zurich, 8057 Zurich, Switzerland; (V.S.); (M.A.)
| | - Matthias Altmeyer
- Department of Molecular Mechanisms of Disease, University of Zurich, 8057 Zurich, Switzerland; (V.S.); (M.A.)
| | - Michael Stebler
- Scientific Center for Optical and Electron Microscopy (ScopeM), ETH Zurich, 8093 Zurich, Switzerland; (R.M.); (M.S.); (S.F.N.)
| | - Simon F. Nørrelykke
- Scientific Center for Optical and Electron Microscopy (ScopeM), ETH Zurich, 8093 Zurich, Switzerland; (R.M.); (M.S.); (S.F.N.)
| | - Peter Horvath
- Synthetic and System Biology Unit, Biological Research Center (BRC), 6726 Szeged, Hungary;
- Institute for Molecular Medicine Finland, University of Helsinki, 00014 Helsinki, Finland
| | - Alessandro A. Sartori
- Institute of Molecular Cancer Research, University of Zurich, 8057 Zurich, Switzerland; (H.A.B.); (S.P.); (C.v.A.); (C.Z.); (K.H.)
| | - Antonio Porro
- Institute of Molecular Cancer Research, University of Zurich, 8057 Zurich, Switzerland; (H.A.B.); (S.P.); (C.v.A.); (C.Z.); (K.H.)
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13
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Krishnan R, Patel PS, Hakem R. BRCA1 and Metastasis: Outcome of Defective DNA Repair. Cancers (Basel) 2021; 14:cancers14010108. [PMID: 35008272 PMCID: PMC8749860 DOI: 10.3390/cancers14010108] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/22/2021] [Accepted: 12/24/2021] [Indexed: 12/12/2022] Open
Abstract
Simple Summary BRCA1 has critical functions in accurately repairing double stand breaks in the DNA through a process known as homologous recombination. BRCA1 also has various functions in other cellular processes that safeguard the genome. Thus, mutations or silencing of this tumor suppressor significantly increases the risk of developing breast, ovarian, and other cancers. Metastasis refers to the spread of cancer to other parts of the body and is the leading cause of cancer-related deaths. In this review, we discuss the mechanisms by which BRCA1 mutations contribute to the metastatic and aggressive nature of the tumor cells. Abstract Heritable mutations in BRCA1 and BRCA2 genes are a major risk factor for breast and ovarian cancer. Inherited mutations in BRCA1 increase the risk of developing breast cancers by up to 72% and ovarian cancers by up to 69%, when compared to individuals with wild-type BRCA1. BRCA1 and BRCA2 (BRCA1/2) are both important for homologous recombination-mediated DNA repair. The link between BRCA1/2 mutations and high susceptibility to breast cancer is well established. However, the potential impact of BRCA1 mutation on the individual cell populations within a tumor microenvironment, and its relation to increased aggressiveness of cancer is not well understood. The objective of this review is to provide significant insights into the mechanisms by which BRCA1 mutations contribute to the metastatic and aggressive nature of the tumor cells.
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Affiliation(s)
- Rehna Krishnan
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada; (R.K.); (P.S.P.)
| | - Parasvi S. Patel
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada; (R.K.); (P.S.P.)
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Razqallah Hakem
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada; (R.K.); (P.S.P.)
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 1A8, Canada
- Correspondence: or
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14
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Sherker A, Chaudhary N, Adam S, Heijink AM, Noordermeer SM, Fradet-Turcotte A, Durocher D. Two redundant ubiquitin-dependent pathways of BRCA1 localization to DNA damage sites. EMBO Rep 2021; 22:e53679. [PMID: 34726323 PMCID: PMC8647010 DOI: 10.15252/embr.202153679] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 10/12/2021] [Accepted: 10/13/2021] [Indexed: 12/31/2022] Open
Abstract
The tumor suppressor BRCA1 accumulates at sites of DNA damage in a ubiquitin‐dependent manner. In this work, we revisit the role of RAP80 in promoting BRCA1 recruitment to damaged chromatin. We find that RAP80 acts redundantly with the BRCA1 RING domain to promote BRCA1 recruitment to DNA damage sites. We show that that RNF8 E3 ligase acts upstream of both the RAP80‐ and RING‐dependent activities, whereas RNF168 acts uniquely upstream of the RING domain. BRCA1 RING mutations that do not impact BARD1 interaction, such as the E2 binding‐deficient I26A mutation, render BRCA1 unable to accumulate at DNA damage sites in the absence of RAP80. Cells that combine BRCA1 I26A and mutations that disable the RAP80–BRCA1 interaction are hypersensitive to PARP inhibition and are unable to form RAD51 foci. Our results suggest that in the absence of RAP80, the BRCA1 E3 ligase activity is necessary for recognition of histone H2A Lys13/Lys15 ubiquitylation by BARD1, although we cannot rule out the possibility that the BRCA1 RING facilitates ubiquitylated nucleosome recognition in other ways.
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Affiliation(s)
- Alana Sherker
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Natasha Chaudhary
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Salomé Adam
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | | | - Sylvie M Noordermeer
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Amélie Fradet-Turcotte
- CHU de Québec Research Center-Université Laval (L'Hôtel-Dieu de Québec), Cancer Research Center, Québec, QC, Canada
| | - Daniel Durocher
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
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15
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Sanchez A, Lee D, Kim DI, Miller KM. Making Connections: Integrative Signaling Mechanisms Coordinate DNA Break Repair in Chromatin. Front Genet 2021; 12:747734. [PMID: 34659365 PMCID: PMC8514019 DOI: 10.3389/fgene.2021.747734] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 08/31/2021] [Indexed: 01/25/2023] Open
Abstract
DNA double-strand breaks (DSBs) are hazardous to genome integrity and can promote mutations and disease if not handled correctly. Cells respond to these dangers by engaging DNA damage response (DDR) pathways that are able to identify DNA breaks within chromatin leading ultimately to their repair. The recognition and repair of DSBs by the DDR is largely dependent on the ability of DNA damage sensing factors to bind to and interact with nucleic acids, nucleosomes and their modified forms to target these activities to the break site. These contacts orientate and localize factors to lesions within chromatin, allowing signaling and faithful repair of the break to occur. Coordinating these events requires the integration of several signaling and binding events. Studies are revealing an enormously complex array of interactions that contribute to DNA lesion recognition and repair including binding events on DNA, as well as RNA, RNA:DNA hybrids, nucleosomes, histone and non-histone protein post-translational modifications and protein-protein interactions. Here we examine several DDR pathways that highlight and provide prime examples of these emerging concepts. A combination of approaches including genetic, cellular, and structural biology have begun to reveal new insights into the molecular interactions that govern the DDR within chromatin. While many questions remain, a clearer picture has started to emerge for how DNA-templated processes including transcription, replication and DSB repair are coordinated. Multivalent interactions with several biomolecules serve as key signals to recruit and orientate proteins at DNA lesions, which is essential to integrate signaling events and coordinate the DDR within the milieu of the nucleus where competing genome functions take place. Genome architecture, chromatin structure and phase separation have emerged as additional vital regulatory mechanisms that also influence genome integrity pathways including DSB repair. Collectively, recent advancements in the field have not only provided a deeper understanding of these fundamental processes that maintain genome integrity and cellular homeostasis but have also started to identify new strategies to target deficiencies in these pathways that are prevalent in human diseases including cancer.
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Affiliation(s)
- Anthony Sanchez
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States.,Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, United States
| | - Doohyung Lee
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States.,Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, United States
| | - Dae In Kim
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States.,Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, United States
| | - Kyle M Miller
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States.,Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, United States.,Livestrong Cancer Institutes, Dell Medical School, The University of Texas at Austin, Austin, TX, United States
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16
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Russi M, Marson D, Fermeglia A, Aulic S, Fermeglia M, Laurini E, Pricl S. The fellowship of the RING: BRCA1, its partner BARD1 and their liaison in DNA repair and cancer. Pharmacol Ther 2021; 232:108009. [PMID: 34619284 DOI: 10.1016/j.pharmthera.2021.108009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 08/22/2021] [Accepted: 09/20/2021] [Indexed: 12/12/2022]
Abstract
The breast cancer type 1 susceptibility protein (BRCA1) and its partner - the BRCA1-associated RING domain protein 1 (BARD1) - are key players in a plethora of fundamental biological functions including, among others, DNA repair, replication fork protection, cell cycle progression, telomere maintenance, chromatin remodeling, apoptosis and tumor suppression. However, mutations in their encoding genes transform them into dangerous threats, and substantially increase the risk of developing cancer and other malignancies during the lifetime of the affected individuals. Understanding how BRCA1 and BARD1 perform their biological activities therefore not only provides a powerful mean to prevent such fatal occurrences but can also pave the way to the development of new targeted therapeutics. Thus, through this review work we aim at presenting the major efforts focused on the functional characterization and structural insights of BRCA1 and BARD1, per se and in combination with all their principal mediators and regulators, and on the multifaceted roles these proteins play in the maintenance of human genome integrity.
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Affiliation(s)
- Maria Russi
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTs), DEA, University of Trieste, Trieste, Italy
| | - Domenico Marson
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTs), DEA, University of Trieste, Trieste, Italy
| | - Alice Fermeglia
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTs), DEA, University of Trieste, Trieste, Italy
| | - Suzana Aulic
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTs), DEA, University of Trieste, Trieste, Italy
| | - Maurizio Fermeglia
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTs), DEA, University of Trieste, Trieste, Italy
| | - Erik Laurini
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTs), DEA, University of Trieste, Trieste, Italy
| | - Sabrina Pricl
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTs), DEA, University of Trieste, Trieste, Italy; Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland.
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17
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Abraxas suppresses DNA end resection and limits break-induced replication by controlling SLX4/MUS81 chromatin loading in response to TOP1 inhibitor-induced DNA damage. Nat Commun 2021; 12:4373. [PMID: 34272385 PMCID: PMC8285526 DOI: 10.1038/s41467-021-24665-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 06/28/2021] [Indexed: 11/08/2022] Open
Abstract
Although homologous recombination (HR) is indicated as a high-fidelity repair mechanism, break-induced replication (BIR), a subtype of HR, is a mutagenic mechanism that leads to chromosome rearrangements. It remains poorly understood how cells suppress mutagenic BIR. Trapping of Topoisomerase 1 by camptothecin (CPT) in a cleavage complex on the DNA can be transformed into single-ended double-strand breaks (seDSBs) upon DNA replication or colliding with transcriptional machinery. Here, we demonstrate a role of Abraxas in limiting seDSBs undergoing BIR-dependent mitotic DNA synthesis. Through counteracting K63-linked ubiquitin modification, Abraxas restricts SLX4/Mus81 recruitment to CPT damage sites for cleavage and subsequent resection processed by MRE11 endonuclease, CtIP, and DNA2/BLM. Uncontrolled SLX4/MUS81 loading and excessive end resection due to Abraxas-deficiency leads to increased mitotic DNA synthesis via RAD52- and POLD3- dependent, RAD51-independent BIR and extensive chromosome aberrations. Our work implicates Abraxas/BRCA1-A complex as a critical regulator that restrains BIR for protection of genome stability.
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18
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BRCA1 and RNAi factors promote repair mediated by small RNAs and PALB2-RAD52. Nature 2021; 591:665-670. [PMID: 33536619 PMCID: PMC8245199 DOI: 10.1038/s41586-020-03150-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 12/21/2020] [Indexed: 01/30/2023]
Abstract
Strong connections exist between R-loops (three-stranded structures harbouring an RNA:DNA hybrid and a displaced single-strand DNA), genome instability and human disease1-5. Indeed, R-loops are favoured in relevant genomic regions as regulators of certain physiological processes through which homeostasis is typically maintained. For example, transcription termination pause sites regulated by R-loops can induce the synthesis of antisense transcripts that enable the formation of local, RNA interference (RNAi)-driven heterochromation6. Pause sites are also protected against endogenous single-stranded DNA breaks by BRCA17. Hypotheses about how DNA repair is enacted at pause sites include a role for RNA, which is emerging as a normal, albeit unexplained, regulator of genome integrity8. Here we report that a species of single-stranded, DNA-damage-associated small RNA (sdRNA) is generated by a BRCA1-RNAi protein complex. sdRNAs promote DNA repair driven by the PALB2-RAD52 complex at transcriptional termination pause sites that form R-loops and are rich in single-stranded DNA breaks. sdRNA repair operates in both quiescent (G0) and proliferating cells. Thus, sdRNA repair can occur in intact tissue and/or stem cells, and may contribute to tumour suppression mediated by BRCA1.
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19
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Panigrahi R, Glover JNM. Structural insights into DNA double-strand break signaling. Biochem J 2021; 478:135-156. [PMID: 33439989 DOI: 10.1042/bcj20200066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 12/10/2020] [Accepted: 12/15/2020] [Indexed: 12/14/2022]
Abstract
Genomic integrity is most threatened by double-strand breaks, which, if left unrepaired, lead to carcinogenesis or cell death. The cell generates a network of protein-protein signaling interactions that emanate from the DNA damage which are now recognized as a rich basis for anti-cancer therapy development. Deciphering the structures of signaling proteins has been an uphill task owing to their large size and complex domain organization. Recent advances in mammalian protein expression/purification and cryo-EM-based structure determination have led to significant progress in our understanding of these large multidomain proteins. This review is an overview of the structural principles that underlie some of the key signaling proteins that function at the double-strand break site. We also discuss some plausible ideas that could be considered for future structural approaches to visualize and build a more complete understanding of protein dynamics at the break site.
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Affiliation(s)
- Rashmi Panigrahi
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - J N Mark Glover
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
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20
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Awate S, Sommers JA, Datta A, Nayak S, Bellani MA, Yang O, Dunn CA, Nicolae CM, Moldovan GL, Seidman MM, Cantor SB, Brosh RM. FANCJ compensates for RAP80 deficiency and suppresses genomic instability induced by interstrand cross-links. Nucleic Acids Res 2020; 48:9161-9180. [PMID: 32797166 DOI: 10.1093/nar/gkaa660] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 07/24/2020] [Accepted: 07/28/2020] [Indexed: 12/16/2022] Open
Abstract
FANCJ, a DNA helicase and interacting partner of the tumor suppressor BRCA1, is crucial for the repair of DNA interstrand crosslinks (ICL), a highly toxic lesion that leads to chromosomal instability and perturbs normal transcription. In diploid cells, FANCJ is believed to operate in homologous recombination (HR) repair of DNA double-strand breaks (DSB); however, its precise role and molecular mechanism is poorly understood. Moreover, compensatory mechanisms of ICL resistance when FANCJ is deficient have not been explored. In this work, we conducted a siRNA screen to identify genes of the DNA damage response/DNA repair regime that when acutely depleted sensitize FANCJ CRISPR knockout cells to a low concentration of the DNA cross-linking agent mitomycin C (MMC). One of the top hits from the screen was RAP80, a protein that recruits repair machinery to broken DNA ends and regulates DNA end-processing. Concomitant loss of FANCJ and RAP80 not only accentuates DNA damage levels in human cells but also adversely affects the cell cycle checkpoint, resulting in profound chromosomal instability. Genetic complementation experiments demonstrated that both FANCJ's catalytic activity and interaction with BRCA1 are important for ICL resistance when RAP80 is deficient. The elevated RPA and RAD51 foci in cells co-deficient of FANCJ and RAP80 exposed to MMC are attributed to single-stranded DNA created by Mre11 and CtIP nucleases. Altogether, our cell-based findings together with biochemical studies suggest a critical function of FANCJ to suppress incompletely processed and toxic joint DNA molecules during repair of ICL-induced DNA damage.
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Affiliation(s)
- Sanket Awate
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH, Baltimore, MD, USA
| | - Joshua A Sommers
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH, Baltimore, MD, USA
| | - Arindam Datta
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH, Baltimore, MD, USA
| | - Sumeet Nayak
- Department of Cancer Biology, University of Massachusetts Medical School - UMASS Memorial Cancer Center, Worcester, MA, USA
| | - Marina A Bellani
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH, Baltimore, MD, USA
| | - Olivia Yang
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, MD, USA
| | - Christopher A Dunn
- Flow Cytometry Unit, National Institute on Aging, NIH, Baltimore, MD, USA
| | - Claudia M Nicolae
- Department of Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, PA, USA
| | - George-Lucian Moldovan
- Department of Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, PA, USA
| | - Michael M Seidman
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH, Baltimore, MD, USA
| | - Sharon B Cantor
- Department of Cancer Biology, University of Massachusetts Medical School - UMASS Memorial Cancer Center, Worcester, MA, USA
| | - Robert M Brosh
- Laboratory of Molecular Gerontology, National Institute on Aging, NIH, Baltimore, MD, USA
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21
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Bellat V, Verchère A, Ashe SA, Law B. Transcriptomic insight into salinomycin mechanisms in breast cancer cell lines: synergistic effects with dasatinib and induction of estrogen receptor β. BMC Cancer 2020; 20:661. [PMID: 32678032 PMCID: PMC7364656 DOI: 10.1186/s12885-020-07134-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 07/02/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Tumors are heterogeneous in nature, composed of different cell populations with various mutations and/or phenotypes. Using a single drug to encounter cancer progression is generally ineffective. To improve the treatment outcome, multiple drugs of distinctive mechanisms but complementary anticancer activities (combination therapy) are often used to enhance antitumor efficacy and minimize the risk of acquiring drug resistance. We report here the synergistic effects of salinomycin (a polyether antibiotic) and dasatinib (a Src kinase inhibitor). METHODS Functionally, both drugs induce cell cycle arrest, intracellular reactive oxygen species (iROS) production, and apoptosis. We rationalized that an overlapping of the drug activities should offer an enhanced anticancer effect, either through vertical inhibition of the Src-STAT3 axis or horizontal suppression of multiple pathways. We determined the toxicity induced by the drug combination and studied the kinetics of iROS production by fluorescence imaging and flow cytometry. Using genomic and proteomic techniques, including RNA-sequencing (RNA-seq), reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and Western Blot, we subsequently identified the responsible pathways that contributed to the synergistic effects of the drug combination. RESULTS Compared to either drug alone, the drug combination showed enhanced potency against MDA-MB-468, MDA-MB-231, and MCF-7 human breast cancer (BC) cell lines and tumor spheroids. The drug combination induces both iROS generation and apoptosis in a time-dependent manner, following a 2-step kinetic profile. RNA-seq data revealed that the drug combination exhibited synergism through horizontal suppression of multiple pathways, possibly through a promotion of cell cycle arrest at the G1/S phase via the estrogen-mediated S-phase entry pathway, and partially via the BRCA1 and DNA damage response pathway. CONCLUSION Transcriptomic analyses revealed for the first time, that the estrogen-mediated S-phase entry pathway partially contributed to the synergistic effect of the drug combination. More importantly, our studies led to the discoveries of new potential therapeutic targets, such as E2F2, as well as a novel drug-induced targeting of estrogen receptor β (ESR2) approach for triple-negative breast cancer treatment, currently lacking of targeted therapies.
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Affiliation(s)
- Vanessa Bellat
- Molecular Imaging Innovations Institute, Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| | - Alice Verchère
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, USA
| | - Sally A Ashe
- Molecular Imaging Innovations Institute, Department of Radiology, Weill Cornell Medicine, New York, NY, USA
| | - Benedict Law
- Molecular Imaging Innovations Institute, Department of Radiology, Weill Cornell Medicine, New York, NY, USA. .,Lead contact, New York, USA.
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22
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Hu Z, Mi S, Zhao T, Peng C, Peng Y, Chen L, Zhu W, Yao Y, Song Q, Li X, Li X, Jia C, Pei H. BGL3 lncRNA mediates retention of the BRCA1/BARD1 complex at DNA damage sites. EMBO J 2020; 39:e104133. [PMID: 32347575 DOI: 10.15252/embj.2019104133] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 03/26/2020] [Accepted: 03/27/2020] [Indexed: 12/12/2022] Open
Abstract
Long non-coding RNAs (lncRNAs) are emerging regulators of genomic stability and human disease. However, the molecular mechanisms by which nuclear lncRNAs directly contribute to DNA damage responses remain largely unknown. Using RNA antisense purification coupled with quantitative mass spectrometry (RAP-qMS), we found that the lncRNA BGL3 binds to PARP1 and BARD1, exhibiting unexpected roles in homologous recombination. Mechanistically, BGL3 is recruited to DNA double-strand breaks (DSBs) by PARP1 at an early time point, which requires its interaction with the DNA-binding domain of PARP1. BGL3 also binds the C-terminal BRCT domain and an internal region (amino acids 127-424) of BARD1, which mediates interaction of the BRCA1/BARD1 complex with its binding partners such as HP1γ and RAD51, resulting in BRCA1/BARD1 retention at DSBs. Cells depleted for BGL3 displayed genomic instability and were sensitive to DNA-damaging reagents. Overall, our findings underscore the biochemical versatility of RNA as a mediator molecule in the DNA damage response pathway, which affects the accumulation of BRCA1/BARD1 at DSBs.
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Affiliation(s)
- Zhaohua Hu
- State Key Laboratory of Proteomics, National Center for Protein Sciences Beijing, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing, China.,Cancer Center, Renmin Hospital of Wuhan University, Wuhan, China
| | - Shaojie Mi
- Cancer Center, Renmin Hospital of Wuhan University, Wuhan, China.,Key Laboratory of Industrial Fermentation Microbiology, Tianjin Industrial Microbiology Key Lab, Ministry of Education, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Ting Zhao
- State Key Laboratory of Proteomics, National Center for Protein Sciences Beijing, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing, China
| | - Changmin Peng
- Department of Biochemistry and Molecular Medicine, The George Washington University School of Medicine and Health Science, Washington, DC, USA.,GW Cancer Center, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Yihan Peng
- Department of Biochemistry and Molecular Medicine, The George Washington University School of Medicine and Health Science, Washington, DC, USA.,GW Cancer Center, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Lulu Chen
- Cancer Center, Renmin Hospital of Wuhan University, Wuhan, China
| | - Wenge Zhu
- Department of Biochemistry and Molecular Medicine, The George Washington University School of Medicine and Health Science, Washington, DC, USA.,GW Cancer Center, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Yi Yao
- Cancer Center, Renmin Hospital of Wuhan University, Wuhan, China
| | - Qibin Song
- Cancer Center, Renmin Hospital of Wuhan University, Wuhan, China
| | - Xiangpan Li
- Cancer Center, Renmin Hospital of Wuhan University, Wuhan, China
| | - Xinzhi Li
- Department of Orthopedics, Affiliated Renhe Hospital of China Three Gorges University, Yichang, Hubei, China
| | - Chenxi Jia
- State Key Laboratory of Proteomics, National Center for Protein Sciences Beijing, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing, China
| | - Huadong Pei
- Department of Biochemistry and Molecular Medicine, The George Washington University School of Medicine and Health Science, Washington, DC, USA.,GW Cancer Center, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
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23
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Liu Y, Lu LY. BRCA1 and homologous recombination: implications from mouse embryonic development. Cell Biosci 2020; 10:49. [PMID: 32257107 PMCID: PMC7106644 DOI: 10.1186/s13578-020-00412-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Accepted: 03/18/2020] [Indexed: 01/30/2023] Open
Abstract
As an important player in DNA damage response, BRCA1 maintains genomic stability and suppresses tumorigenesis by promoting DNA double-strand break (DSB) repair through homologous recombination (HR). Since the cloning of BRCA1 gene, many Brca1 mutant alleles have been generated in mice. Mice carrying homozygous Brca1 mutant alleles are embryonic lethal, suggesting that BRCA1's functions are important for embryonic development. Studies of embryonic development in Brca1 mutant mice not only reveal the physiological significance of BRCA1's known function in HR, but also lead to the discovery of BRCA1's new function in HR: regulation of DSB repair pathway choice.
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Affiliation(s)
- Yidan Liu
- 1Key Laboratory of Reproductive Genetics (Ministry of Education) and Women's Reproductive Health Laboratory of Zhejiang Province, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Lin-Yu Lu
- 1Key Laboratory of Reproductive Genetics (Ministry of Education) and Women's Reproductive Health Laboratory of Zhejiang Province, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China.,2Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
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24
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Wu X, Liu S, Sagum C, Chen J, Singh R, Chaturvedi A, Horton JR, Kashyap TR, Fushman D, Cheng X, Bedford MT, Wang B. Crosstalk between Lys63- and Lys11-polyubiquitin signaling at DNA damage sites is driven by Cezanne. Genes Dev 2019; 33:1702-1717. [PMID: 31699778 PMCID: PMC6942045 DOI: 10.1101/gad.332395.119] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 10/16/2019] [Indexed: 11/25/2022]
Abstract
The establishment of polyubiquitin conjugates with distinct linkages play important roles in the DNA damage response. Much remains unknown about the regulation of linkage-specific ubiquitin signaling at sites of DNA damage. Here we reveal that Cezanne (also known as Otud7B) deubiquitinating enzyme promotes the recruitment of Rap80/BRCA1-A complex by binding to Lys63-polyubiquitin and targeting Lys11-polyubiquitin. Using a ubiquitin binding domain protein array screen, we identify that the UBA domains of Cezanne and Cezanne2 (also known as Otud7A) selectively bind to Lys63-linked polyubiquitin. Increased Lys11-linkage ubiquitination due to lack of Cezanne DUB activity compromises the recruitment of Rap80/BRCA1-A. Cezanne2 interacts with Cezanne, facilitating Cezanne in the recruitment of Rap80/BRCA1-A, Rad18, and 53BP1, in cellular resistance to ionizing radiation and DNA repair. Our work presents a model that Cezanne serves as a "reader" of the Lys63-linkage polyubiquitin at DNA damage sites and an "eraser" of the Lys11-linkage ubiquitination, indicating a crosstalk between linkage-specific ubiquitination at DNA damage sites.
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Affiliation(s)
- Xiao Wu
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Shichang Liu
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Cari Sagum
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Jianji Chen
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | | | | | - John R Horton
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Tanuja R Kashyap
- Department of Chemistry & Biochemistry, University of Maryland, College Park, Maryland 20742, USA
| | - David Fushman
- Department of Chemistry & Biochemistry, University of Maryland, College Park, Maryland 20742, USA
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Mark T Bedford
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Bin Wang
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA.,Genetics and Epigenetics Program, The University of Texas MD Anderson Cancer Center UT Health Graduate School of Biomedical Sciences, Houston, Texas 77030, USA
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25
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Demarest TG, Babbar M, Okur MN, Dan X, Croteau DL, Fakouri NB, Mattson MP, Bohr VA. NAD+Metabolism in Aging and Cancer. ANNUAL REVIEW OF CANCER BIOLOGY-SERIES 2019. [DOI: 10.1146/annurev-cancerbio-030518-055905] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Aging is a major risk factor for many types of cancer, and the molecular mechanisms implicated in aging, progeria syndromes, and cancer pathogenesis display considerable similarities. Maintaining redox homeostasis, efficient signal transduction, and mitochondrial metabolism is essential for genome integrity and for preventing progression to cellular senescence or tumorigenesis. NAD+is a central signaling molecule involved in these and other cellular processes implicated in age-related diseases and cancer. Growing evidence implicates NAD+decline as a major feature of accelerated aging progeria syndromes and normal aging. Administration of NAD+precursors such as nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN) offer promising therapeutic strategies to improve health, progeria comorbidities, and cancer therapies. This review summarizes insights from the study of aging and progeria syndromes and discusses the implications and therapeutic potential of the underlying molecular mechanisms involved in aging and how they may contribute to tumorigenesis.
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Affiliation(s)
- Tyler G. Demarest
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA
- Laboratory of Neurosciences, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA
| | - Mansi Babbar
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA
| | - Mustafa N. Okur
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA
| | - Xiuli Dan
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA
| | - Deborah L. Croteau
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA
| | - Nima B. Fakouri
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA
| | - Mark P. Mattson
- Laboratory of Neurosciences, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA
| | - Vilhelm A. Bohr
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA
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26
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Functional Analysis of Promoter Variants in Genes Involved in Sex Steroid Action, DNA Repair and Cell Cycle Control. Genes (Basel) 2019; 10:genes10030186. [PMID: 30823486 PMCID: PMC6470759 DOI: 10.3390/genes10030186] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/09/2019] [Accepted: 02/21/2019] [Indexed: 01/16/2023] Open
Abstract
Genetic variants affecting the regulation of gene expression are among the main causes of human diversity. The potential importance of regulatory polymorphisms is underscored by results from Genome Wide Association Studies, which have already implicated such polymorphisms in the susceptibility to complex diseases such as breast cancer. In this study, we re-sequenced the promoter regions of 24 genes involved in pathways related to breast cancer including sex steroid action, DNA repair, and cell cycle control in 60 unrelated Caucasian individuals. We constructed haplotypes and assessed the functional impact of promoter variants using gene reporter assays and electrophoretic mobility shift assays. We identified putative functional variants within the promoter regions of estrogen receptor 1 (ESR1), ESR2, forkhead box A1 (FOXA1), ubiquitin interaction motif containing 1 (UIMC1) and cell division cycle 7 (CDC7). The functional polymorphism on CDC7, rs13447455, influences CDC7 transcriptional activity in an allele-specific manner and alters DNA–protein complex formation in breast cancer cell lines. Moreover, results from the Breast Cancer Association Consortium show a marginal association between rs13447455 and breast cancer risk (p = 9.3 × 10−5), thus warranting further investigation. Furthermore, our study has helped provide methodological solutions to some technical difficulties that were encountered with gene reporter assays, particularly regarding inter-clone variability and statistical consistency.
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27
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Balmus G, Pilger D, Coates J, Demir M, Sczaniecka-Clift M, Barros AC, Woods M, Fu B, Yang F, Chen E, Ostermaier M, Stankovic T, Ponstingl H, Herzog M, Yusa K, Martinez FM, Durant ST, Galanty Y, Beli P, Adams DJ, Bradley A, Metzakopian E, Forment JV, Jackson SP. ATM orchestrates the DNA-damage response to counter toxic non-homologous end-joining at broken replication forks. Nat Commun 2019; 10:87. [PMID: 30622252 PMCID: PMC6325118 DOI: 10.1038/s41467-018-07729-2] [Citation(s) in RCA: 119] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 11/15/2018] [Indexed: 02/02/2023] Open
Abstract
Mutations in the ATM tumor suppressor gene confer hypersensitivity to DNA-damaging chemotherapeutic agents. To explore genetic resistance mechanisms, we performed genome-wide CRISPR-Cas9 screens in cells treated with the DNA topoisomerase I inhibitor topotecan. Thus, we here establish that inactivating terminal components of the non-homologous end-joining (NHEJ) machinery or of the BRCA1-A complex specifically confer topotecan resistance to ATM-deficient cells. We show that hypersensitivity of ATM-mutant cells to topotecan or the poly-(ADP-ribose) polymerase (PARP) inhibitor olaparib reflects delayed engagement of homologous recombination at DNA-replication-fork associated single-ended double-strand breaks (DSBs), allowing some to be subject to toxic NHEJ. Preventing DSB ligation by NHEJ, or enhancing homologous recombination by BRCA1-A complex disruption, suppresses this toxicity, highlighting a crucial role for ATM in preventing toxic LIG4-mediated chromosome fusions. Notably, suppressor mutations in ATM-mutant backgrounds are different to those in BRCA1-mutant scenarios, suggesting new opportunities for patient stratification and additional therapeutic vulnerabilities for clinical exploitation.
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Affiliation(s)
- Gabriel Balmus
- The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
- UK Dementia Research Institute and Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0AH, UK
| | - Domenic Pilger
- The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Julia Coates
- The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Mukerrem Demir
- The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Matylda Sczaniecka-Clift
- The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Ana C Barros
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Michael Woods
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Beiyuan Fu
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Fengtang Yang
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Elisabeth Chen
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | | | - Tatjana Stankovic
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Hannes Ponstingl
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Mareike Herzog
- The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Kosuke Yusa
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Francisco Munoz Martinez
- The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Stephen T Durant
- DNA Damage Response Biology, Bioscience Oncology IMED Biotech Unit, AstraZeneca, Cambridge, CB4 0WG, UK
| | - Yaron Galanty
- The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Petra Beli
- Institute of Molecular Biology (IMB), 55128, Mainz, Germany
| | - David J Adams
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Allan Bradley
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Emmanouil Metzakopian
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
- UK Dementia Research Institute and Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0AH, UK
| | - Josep V Forment
- The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK.
- DNA Damage Response Biology, Bioscience Oncology IMED Biotech Unit, AstraZeneca, Cambridge, CB4 0WG, UK.
| | - Stephen P Jackson
- The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK.
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28
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Sei-1 promotes double minute chromosomes formation through activation of the PI3K/Akt/BRCA1-Abraxas pathway and induces double-strand breaks in NIH-3T3 fibroblasts. Cell Death Dis 2018; 9:341. [PMID: 29497033 PMCID: PMC5832785 DOI: 10.1038/s41419-018-0362-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 01/24/2018] [Accepted: 01/29/2018] [Indexed: 12/29/2022]
Abstract
Sei-1 is a potential oncogene that plays an important role in promoting genomic instability. Double minute chromosomes (DMs) are hallmarks of gene amplification and contribute to tumorigenesis. Defects in the DNA double-strand break (DSB) repairing pathways can lead to gene amplification. To date, the mechanisms governing the formation of DMs induced by Sei-1 are not fully understood. We established DMs induced by Sei-1 in the NIH-3T3 cell line. RNA-sequencing was used to identify key characteristics of differentially expressed genes. Metaphase spreads were used to calculate DM numbers. Immunofluorescence was employed to detect γH2AX foci. Western blot and Akt pathway inhibition experiments were performed to reveal the role of the PI3K/Akt/BRCA1-Abraxas pathway in Sei-1-induced DMs. Luciferase reporter assay was employed to explore the regulatory mechanisms between Sei-1 and BRCA1. DM formation was associated with a deficiency in DSB repair. Based on this finding, activation of the PI3K/Akt/BRCA1-Abraxas pathway was found to increase the DM population with passage in vivo, and inhibition resulted in a reduction of DMs. Apart from this, it was shown for the first time that Sei-1 could directly regulate the expression of BRCA1. Our results suggest that the PI3K/Akt/BRCA1-Abraxas pathway is responsible for the formation of DMs induced by Sei-1.
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29
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Sharma B, Preet Kaur R, Raut S, Munshi A. BRCA1 mutation spectrum, functions, and therapeutic strategies: The story so far. Curr Probl Cancer 2018; 42:189-207. [PMID: 29452958 DOI: 10.1016/j.currproblcancer.2018.01.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 12/19/2017] [Accepted: 01/04/2018] [Indexed: 02/07/2023]
Abstract
BRCA1 gene mutations account for about 25-28% of hereditary Breast Cancer as BRCA1 is included in the category of high penetrance genes. Except for few commonmutations, there is a heterogenous spectrum of BRCA1 mutations in various ethnic groups. 185AGdel and 5382ins Care the most common BRCA1 alterations (founder mutations) which have been identified in most of the population. This review has been compiled with an aim to consolidate the information on genetic variants reported in BRCA1 found in various ethnic groups, their functional implications if known; involvement of BRCA1 in various cellular pathways/processes and potential BRCA1 targeted therapies. The pathological variations of BRCA1 vary among different ethical groups. A systematic search in PubMed and Google scholar for the literature on BRCA1 gene was carried out to figure out structure and function of BRCA1 gene. BRCA1 is a large protein having 1863 amino acids with multiple functional domains and interacts with multiple proteins to carry out various crucial cellular processes. BRCA1 plays a major role in maintaining genome integrity, transcription regulation, chromatin remodeling, cell cycle checkpoint control, DNA damage repair, chromosomal segregation, and apoptosis. Studies investigating the phenotypic response of mutant BRCA1 protein and comparing it to wildtype BRCA1 protein are clinically important as they are involved in homologous recombination and other repair mechanisms. These studies may help in developing more targetted therapies, detecting novel interacting partners, identification of new signaling pathways that BRCA1 is a part of or downstream target genes that BRCA1 affects.
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Affiliation(s)
- Babita Sharma
- Department of Human Genetics and Molecular Medicine, Central University of Punjab, Bathinda, Punjab, India
| | - Raman Preet Kaur
- Department of Human Genetics and Molecular Medicine, Central University of Punjab, Bathinda, Punjab, India
| | - Sonali Raut
- Department of Human Genetics and Molecular Medicine, Central University of Punjab, Bathinda, Punjab, India
| | - Anjana Munshi
- Department of Human Genetics and Molecular Medicine, Central University of Punjab, Bathinda, Punjab, India.
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30
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Abro1 maintains genome stability and limits replication stress by protecting replication fork stability. Genes Dev 2017; 31:1469-1482. [PMID: 28860160 PMCID: PMC5588928 DOI: 10.1101/gad.299172.117] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 07/26/2017] [Indexed: 01/19/2023]
Abstract
Xu et al. show that Abro1 localizes to stalled replication forks and protects stalled replication fork stability in response to replication stress by inhibiting DNA2 nuclease/WRN helicase-mediated degradation of stalled forks. Protection of the stalled replication fork is crucial for responding to replication stress and minimizing its impact on chromosome instability, thus preventing diseases, including cancer. We found a new component, Abro1, in the protection of stalled replication fork integrity. Abro1 deficiency results in increased chromosome instability, and Abro1-null mice are tumor-prone. We show that Abro1 protects stalled replication fork stability by inhibiting DNA2 nuclease/WRN helicase-mediated degradation of stalled forks. Depletion of RAD51 prevents the DNA2/WRN-dependent degradation of stalled forks in Abro1-deficient cells. This mechanism is distinct from the BRCA2-dependent fork protection pathway, in which stable RAD51 filament formation prevents MRE11-dependent degradation of the newly synthesized DNA at stalled forks. Thus, our data reveal a new aspect of regulated protection of stalled replication forks that involves Abro1.
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31
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Kyrieleis OJP, McIntosh PB, Webb SR, Calder LJ, Lloyd J, Patel NA, Martin SR, Robinson CV, Rosenthal PB, Smerdon SJ. Three-Dimensional Architecture of the Human BRCA1-A Histone Deubiquitinase Core Complex. Cell Rep 2017; 17:3099-3106. [PMID: 28009280 PMCID: PMC5199339 DOI: 10.1016/j.celrep.2016.11.063] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 11/10/2016] [Accepted: 11/21/2016] [Indexed: 12/31/2022] Open
Abstract
BRCA1 is a tumor suppressor found to be mutated in hereditary breast and ovarian cancer and plays key roles in the maintenance of genomic stability by homologous recombination repair. It is recruited to damaged chromatin as a component of the BRCA1-A deubiquitinase, which cleaves K63-linked ubiquitin chains attached to histone H2A and H2AX. BRCA1-A contributes to checkpoint regulation, repair pathway choice, and HR repair efficiency through molecular mechanisms that remain largely obscure. The structure of an active core complex comprising two Abraxas/BRCC36/BRCC45/MERIT40 tetramers determined by negative-stain electron microscopy (EM) reveals a distorted V-shape architecture in which a dimer of Abraxas/BRCC36 heterodimers sits at the base, with BRCC45/Merit40 pairs occupying each arm. The location and ubiquitin-binding activity of BRCC45 suggest that it may provide accessory interactions with nucleosome-linked ubiquitin chains that contribute to their efficient processing. Our data also suggest how ataxia telangiectasia mutated (ATM)-dependent BRCA1 dimerization may stabilize self-association of the entire BRCA1-A complex.
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Affiliation(s)
- Otto J P Kyrieleis
- Structural Biology of DNA-Damage Signalling Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Pauline B McIntosh
- Structural Biology of Cells and Viruses Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Sarah R Webb
- Structural Biology of DNA-Damage Signalling Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Lesley J Calder
- Structural Biology of Cells and Viruses Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Janette Lloyd
- Structural Biology of DNA-Damage Signalling Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Nisha A Patel
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, OX1 3QZ Oxford, UK
| | - Stephen R Martin
- Structural Biology Technology Platform, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Carol V Robinson
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, OX1 3QZ Oxford, UK
| | - Peter B Rosenthal
- Structural Biology of Cells and Viruses Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
| | - Stephen J Smerdon
- Structural Biology of DNA-Damage Signalling Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
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RNF8- and Ube2S-Dependent Ubiquitin Lysine 11-Linkage Modification in Response to DNA Damage. Mol Cell 2017; 66:458-472.e5. [PMID: 28525740 DOI: 10.1016/j.molcel.2017.04.013] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 12/22/2016] [Accepted: 04/18/2017] [Indexed: 11/22/2022]
Abstract
Ubiquitin modification of proteins plays pivotal roles in the cellular response to DNA damage. Given the complexity of ubiquitin conjugation due to the formation of poly-conjugates of different linkages, functional roles of linkage-specific ubiquitin modification at DNA damage sites are largely unclear. We identify that Lys11-linkage ubiquitin modification occurs at DNA damage sites in an ATM-dependent manner, and ubiquitin-modifying enzymes, including Ube2S E2-conjugating enzyme and RNF8 E3 ligase, are responsible for the assembly of Lys11-linkage conjugates on damaged chromatin, including histone H2A/H2AX. We show that RNF8- and Ube2S-dependent Lys11-linkage ubiquitin conjugation plays an important role in regulating DNA damage-induced transcriptional silencing, distinct from the role of Lys63-linkage ubiquitin in the recruitment of DNA damage repair proteins 53BP1 and BRCA1. Thus, our study highlights the importance of linkage-specific ubiquitination at DNA damage sites, and it reveals that Lys11-linkage ubiquitin modification plays a crucial role in the DNA damage response.
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Genetic evaluation of BRCA1 associated a complex genes with triple-negative breast cancer susceptibility in Chinese women. Oncotarget 2016; 7:9759-72. [PMID: 26848770 PMCID: PMC4891082 DOI: 10.18632/oncotarget.7112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 01/18/2016] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND The tumor suppressor BRCA1 plays a pivotal role in maintaining genomic stability and tumor suppression. The BRCA1-A complex is required for recruitment of BRCA1 to DNA damage sites, DNA repair and cell cycle checkpoint control. Since germline mutations of BRCA1 often lead to breast tumors that are triple-negative breast cancer (TNBC) type, we aimed to investigate whether genetic deficiency in genes of the BRCA1-A complex is associated with risk to TNBC development. RESULTS We found that rs7250266 in the promoter region of NBA1 confers a decreased risk to TNBC development, but not to non-TNBC susceptibility. In addition, the haplotypes containing two polymorphisms rs7250266 and rs2278256 are associated with a lower chance of TNBC development specifically. Our studies also showed that the protective alleles of rs7250266 (C > G) and rs2278256 (T > C) down-regulate promoter activity of NBA1 in mammary epithelial cells. METHODS We investigated associations between the BRCA1-A complex genes and TNBC developing risk in first case-control study of Chinese Han Women population including 414 patients with TNBC and 354 cancer-free controls. We detected 37 common variants in ABRAXAS, RAP80, BRE, BRCC36 and NBA1/MERIT40 genes encoding the BRCA1-A complex and evaluated their genetic susceptibility to the risk of TNBC. An additional cohort with 652 other types of breast cancer (non-TNBC) cases and 890 controls was used to investigate the associations between TNBC-specific SNPs genotype and non-TNBCs susceptibility. CONCLUSIONS Genetic variants in NBA1 may be an important genetic determinant of TNBC susceptibility. Further investigation and validation of these SNPs in larger cohorts may facilitate in predication and prevention of TNBC and in counseling individuals for risk of TNBC development.
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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: 2.5] [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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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: 53] [Impact Index Per Article: 6.6] [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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Fang Y, Zhang Q, Wang X, Yang X, Wang X, Huang Z, Jiao Y, Wang J. Quantitative phosphoproteomics reveals genistein as a modulator of cell cycle and DNA damage response pathways in triple-negative breast cancer cells. Int J Oncol 2016; 48:1016-28. [PMID: 26783066 PMCID: PMC4750531 DOI: 10.3892/ijo.2016.3327] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 12/15/2015] [Indexed: 12/14/2022] Open
Abstract
Around one sixth of breast cancer cases are classified as triple-negative breast cancer (TNBC), named after the absence of the expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2); however, patients with TNBC suffer from poor clinical outcome and shortage of targeted therapy. Genistein, an estrogenic soy isoflavone, shows anticancer effects in TNBC cells such as inducing G2/M cell cycle arrest and apoptosis. However, the underlying mechanism of its anticancer effects is poorly understood and its elucidation can help the development of novel therapeutic strategies for TNBC. In this study, by combining isobaric tag-based TMT labeling with titanium dioxide-based phosphopeptide enrichment, we quantitated 5,445 phosphorylation sites on 2,008 phosphoproteins in the TNBC cell line MDA-MB-231, upon genistein treatment. Our analysis revealed 332 genistein-regulated phosphorylation sites on 226 proteins. Our data show that genistein can regulate several biological processes during the cell cycle, including DNA replication, cohesin complex cleavage, and kinetochore formation. Furthermore, genistein can also activate DNA damage response, including activation of ATR and BRCA1 complex. Overall, our study presents evidence at a phosphoproteomic level that genistein is able to inhibit TNBC cell growth by regulating the cell cycle and DNA damage response in a more complex manner. Our findings help elucidate the mechanisms through which genistein exerts its anticancer effects in TNBC cells.
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Affiliation(s)
- Yi Fang
- Department of Breast Surgical Oncology, Cancer Institute and Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P.R. China
| | - Qian Zhang
- Department of Gastroenterology, Beijing Tiantan Hospital, Capital Medical University, Beijing, P.R. China
| | - Xin Wang
- Department of Breast Surgical Oncology, Cancer Institute and Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P.R. China
| | - Xue Yang
- Department of Breast Surgical Oncology, Cancer Institute and Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P.R. China
| | - Xiangyu Wang
- Department of Breast Surgical Oncology, Cancer Institute and Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P.R. China
| | - Zhen Huang
- Department of Abdominal Surgical Oncology, Cancer Institute and Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P.R. China
| | - Yuchen Jiao
- Laboratory of Cell and Molecular Biology and State Key Laboratory of Molecular Oncology, Cancer Institute and Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P.R. China
| | - Jing Wang
- Department of Breast Surgical Oncology, Cancer Institute and Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P.R. China
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37
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Brca1 deficiency causes bone marrow failure and spontaneous hematologic malignancies in mice. Blood 2015; 127:310-3. [PMID: 26644450 DOI: 10.1182/blood-2015-03-635599] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 09/12/2015] [Indexed: 01/05/2023] Open
Abstract
BRCA1 is critical for maintenance of genomic stability and interacts directly with several proteins that regulate hematopoietic stem cell function and are part of the Fanconi anemia (FA) double-strand break DNA repair pathway. The effects of complete BRCA1 deficiency on bone marrow (BM) function are unknown. To test the hypothesis that Brca1 is essential in hematopoiesis, we developed a conditional mouse model with Mx1-Cre-mediated Brca1 deletion. Mice lacking Brca1 in the BM have baseline cytopenias and develop spontaneous bone marrow failure or diverse hematologic malignancies by 6 months of age. Brca1(-/-) BM cells have a reduced capacity to form hematopoietic colonies in vitro and to reconstitute hematopoiesis in irradiated recipients, consistent with a hematopoietic progenitor functional defect. Brca1(-/-) BM cells also show FA-like hypersensitivity to the DNA crosslinking agent mitomycin C, and karyotypes feature genomic instability. Taken together, our results show that loss of Brca1 in murine BM causes hematopoietic defects similar to those seen in people with FA, which provides strong evidence that Brca1 is critical for normal hematopoiesis and that Brca1 is a bona fide FA-like gene.
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38
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Donninger H, Hobbing K, Schmidt ML, Walters E, Rund L, Schook L, Clark GJ. A porcine model system of BRCA1 driven breast cancer. Front Genet 2015; 6:269. [PMID: 26379698 PMCID: PMC4548227 DOI: 10.3389/fgene.2015.00269] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 08/06/2015] [Indexed: 12/19/2022] Open
Abstract
BRCA1 is a breast and ovarian tumor suppressor. Hereditary mutations in BRCA1 result in a predisposition to breast cancer, and BRCA1 expression is down-regulated in ~30% of sporadic cases. The function of BRCA1 remains poorly understood, but it appears to play an important role in DNA repair and the maintenance of genetic stability. Mouse models of BRCA1 deficiency have been developed in an attempt to understand the role of the gene in vivo. However, the subtle nature of BRCA1 function and the well-known discrepancies between human and murine breast cancer biology and genetics may limit the utility of mouse systems in defining the function of BRCA1 in cancer and validating the development of novel therapeutics for breast cancer. In contrast to mice, pig biological systems, and cancer genetics appear to more closely resemble their human counterparts. To determine if BRCA1 inactivation in pig cells promotes their transformation and may serve as a model for the human disease, we developed an immortalized porcine breast cell line and stably inactivated BRCA1 using miRNA. The cell line developed characteristics of breast cancer stem cells and exhibited a transformed phenotype. These results validate the concept of using pigs as a model to study BRCA1 defects in breast cancer and establish the first porcine breast tumor cell line.
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Affiliation(s)
- Howard Donninger
- Department of Medicine, James Graham Brown Cancer Center, University of Louisville Louisville, KY, USA
| | - Katharine Hobbing
- Department of Pharmacology and Toxicology, James Graham Brown Cancer Center, University of Louisville Louisville, KY, USA
| | - M L Schmidt
- Department of Biochemistry, University of Louisville Louisville, KY, USA
| | - Eric Walters
- Division of Animal Sciences, National Swine Resource and Research Center, University of Missouri Columbia, MO, USA
| | - Laurie Rund
- Department of Animal Sciences, University of Illinois at Urbana-Champaign Urbana, IL, USA
| | - Larry Schook
- Department of Animal Sciences, University of Illinois at Urbana-Champaign Urbana, IL, USA
| | - Geoffrey J Clark
- Department of Pharmacology and Toxicology, James Graham Brown Cancer Center, University of Louisville Louisville, KY, USA
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39
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Takata KI, Tomida J, Reh S, Swanhart LM, Takata M, Hukriede NA, Wood RD. Conserved overlapping gene arrangement, restricted expression, and biochemical activities of DNA polymerase ν (POLN). J Biol Chem 2015; 290:24278-93. [PMID: 26269593 PMCID: PMC4591814 DOI: 10.1074/jbc.m115.677419] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Indexed: 12/12/2022] Open
Abstract
DNA polymerase ν (POLN) is one of 16 DNA polymerases encoded in vertebrate genomes. It is important to determine its gene expression patterns, biological roles, and biochemical activities. By quantitative analysis of mRNA expression, we found that POLN from the zebrafish Danio rerio is expressed predominantly in testis. POLN is not detectably expressed in zebrafish embryos or in mouse embryonic stem cells. Consistent with this, injection of POLN-specific morpholino antisense oligonucleotides did not interfere with zebrafish embryonic development. Analysis of transcripts revealed that vertebrate POLN has an unusual gene expression arrangement, sharing a first exon with HAUS3, the gene encoding augmin-like complex subunit 3. HAUS3 is broadly expressed in embryonic and adult tissues, in contrast to POLN. Differential expression of POLN and HAUS3 appears to arise by alternate splicing of transcripts in mammalian cells and zebrafish. When POLN was ectopically overexpressed in human cells, it specifically coimmunoprecipitated with the homologous recombination factors BRCA1 and FANCJ, but not with previously suggested interaction partners (HELQ and members of the Fanconi anemia core complex). Purified zebrafish POLN protein is capable of thymine glycol bypass and strand displacement, with activity dependent on a basic amino acid residue known to stabilize the primer-template. These properties are conserved with the human enzyme. Although the physiological function of pol ν remains to be clarified, this study uncovers distinctive aspects of its expression control and evolutionarily conserved properties of this DNA polymerase.
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Affiliation(s)
- Kei-Ichi Takata
- From the Department of Epigenetics and Molecular Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Smithville, Texas 78957, the University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030,
| | - Junya Tomida
- From the Department of Epigenetics and Molecular Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Smithville, Texas 78957, the University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030
| | - Shelley Reh
- From the Department of Epigenetics and Molecular Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Smithville, Texas 78957, the University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030
| | - Lisa M Swanhart
- the Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, and
| | - Minoru Takata
- the Laboratory of DNA Damage Signaling, Department of Late Effects Studies, Radiation Biology Center, Kyoto University, Kyoto 606-8501, Japan
| | - Neil A Hukriede
- the Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, and
| | - Richard D Wood
- From the Department of Epigenetics and Molecular Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Smithville, Texas 78957, the University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030
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40
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Protein stability versus function: effects of destabilizing missense mutations on BRCA1 DNA repair activity. Biochem J 2015; 466:613-24. [DOI: 10.1042/bj20141077] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The majority of the unstable BRCA1 BRCT domain missense mutations we studied disrupted DNA repair in vivo, but reduced cellular function only weakly correlated with reduced structural stability. The findings have an impact on assessing cancer susceptibility in patients with BRCA1 mutations.
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41
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Long DT, Joukov V, Budzowska M, Walter JC. BRCA1 promotes unloading of the CMG helicase from a stalled DNA replication fork. Mol Cell 2014; 56:174-85. [PMID: 25219499 DOI: 10.1016/j.molcel.2014.08.012] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 06/30/2014] [Accepted: 08/07/2014] [Indexed: 11/19/2022]
Abstract
The tumor suppressor protein BRCA1 promotes homologous recombination (HR), a high-fidelity mechanism to repair DNA double-strand breaks (DSBs) that arise during normal replication and in response to DNA-damaging agents. Recent genetic experiments indicate that BRCA1 also performs an HR-independent function during the repair of DNA interstrand crosslinks (ICLs). Here we show that BRCA1 is required to unload the CMG helicase complex from chromatin after replication forks collide with an ICL. Eviction of the stalled helicase allows leading strands to be extended toward the ICL, followed by endonucleolytic processing of the crosslink, lesion bypass, and DSB repair. Our results identify BRCA1-dependent helicase unloading as a critical, early event in ICL repair.
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Affiliation(s)
- David T Long
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Vladimir Joukov
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Magda Budzowska
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Johannes C Walter
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA.
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42
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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: 28] [Impact Index Per Article: 2.8] [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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43
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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: 1.1] [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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44
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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: 1.9] [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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BRCA1, LMO4, and CtIP mRNA expression in erlotinib-treated non-small-cell lung cancer patients with EGFR mutations. J Thorac Oncol 2013; 8:295-300. [PMID: 23407556 DOI: 10.1097/jto.0b013e31827db621] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
INTRODUCTION Lung adenocarcinoma patients harboring EGFR activating mutations attain improved progression-free survival (PFS) with treatment with epidermal growth factor receptor tyrosine kinase inhibitors. However, patients ultimately relapse, indicating that other genetic factors could influence outcome in such patients. We hypothesized that PFS could be influenced by the expression of genes in DNA repair pathways. METHODS We examined the mRNA expression of C terminus-binding protein-interacting protein and Lin11, Isl-1, and Mec-3 domain only 4 (LMO4) in pretreatment tumor samples from 91 erlotinib-treated advanced non-small-cell lung cancer patients with EGFR mutations in whom breast cancer gene 1 (BRCA1) expression and the concomitant presence of the EGFR T790M mutation had previously been assessed. Gene expression was analyzed by polymerase chain reaction, using β-actin as endogenous gene. Results were correlated with PFS and overall survival. RESULTS In patients with low LMO4 levels, PFS was 13 months, whereas it was not reached for those with high LMO4 levels (p = 0.03). In patients with low levels of both BRCA1 and LMO4, PFS was 19 months whereas it was not reached in those with low BRCA1 and high LMO4 mRNA levels (p = 0.04). In patients with high BRCA1 and low LMO4 levels, PFS was 8 months, whereas it was 18 months in those with high levels of both genes (p = 0.03). CONCLUSIONS Low BRCA1 and high LMO4 levels were associated with longer PFS to erlotinib. Baseline assessment of BRCA1 and LMO4 mRNA expression can help predict outcome to erlotinib.
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Abstract
Mutations of the breast and ovarian cancer susceptibility gene 1 (BRCA1) account for about 40-45% of hereditary breast cancer cases. Moreover, a significant fraction of sporadic (non-hereditary) breast and ovarian cancers exhibit reduced or absent expression of the BRCA1 protein, suggesting an additional role for BRCA1 in sporadic cancers. BRCA1 follows the classic pattern of a highly penetrant Knudsen-type tumor suppressor gene in which one allele is inactivated through a germ-line mutation and the other is mutated or deleted within the tumor. BRCA1 is a multi-functional protein but it is not fully understood which function(s) is (are) most important for tumor suppression, nor is it clear why BRCA1-mutations confer a high risk for breast and ovarian cancers and not a broad spectrum of tumor types. Here, we will review BRCA1 functions in the DNA damage response (DDR), which are likely to contribute to tumor suppression. In the process, we will highlight some of the controversies and unresolved issues in the field. We will also describe a recently identified and under-investigated role for BRCA1 in the regulation of telomeres and the implications of this role in the DDR and cancer suppression.
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Affiliation(s)
- Eliot M Rosen
- Department of Oncology, Georgetown University School of Medicine Washington, DC, USA ; Department of Biochemistry, Molecular and Cellular Biology, Georgetown University School of Medicine Washington, DC, USA ; Department of Radiation Medicine, Georgetown University School of Medicine Washington, DC, USA
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Biomedical text mining and its applications in cancer research. J Biomed Inform 2013; 46:200-11. [DOI: 10.1016/j.jbi.2012.10.007] [Citation(s) in RCA: 159] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 10/30/2012] [Accepted: 10/30/2012] [Indexed: 11/21/2022]
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Expression of human BRCA1Δ17-19 alternative splicing variant with a truncated BRCT domain in MCF-7 cells results in impaired assembly of DNA repair complexes and aberrant DNA damage response. Cell Signal 2013; 25:1186-93. [PMID: 23416467 DOI: 10.1016/j.cellsig.2013.02.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 02/08/2013] [Indexed: 11/23/2022]
Abstract
Alternative pre-mRNA splicing is a fundamental post-transcriptional regulatory mechanism. Cancer-specific misregulation of the splicing process may lead to formation of irregular alternative splicing variants (ASVs) with a potentially negative impact on cellular homeostasis. Alternative splicing of BRCA1 pre-mRNA can give rise to BRCA1 protein isoforms that possess dramatically altered biological activities compared with full-length wild-type BRCA1. During the screening of high-risk breast cancer (BC) families we ascertained numerous BRCA1 ASVs, however, their clinical significance for BC development is largely unknown. In this study, we examined the influence of the BRCA1Δ17-19 ASV, which lacks a portion of the BRCT domain, on DNA repair capacity using human MCF-7 BC cell clones with stably modified BRCA1 expression. Our results show that overexpression of BRCA1Δ17-19 impairs homologous recombination repair (sensitizes cells to mitomycin C), delays repair of ionizing radiation-induced DNA damage and dynamics of the ionizing radiation-induced foci (IRIF) formation, and undermines also the non-homologous end joining repair (NHEJ) activity. Mechanistically, BRCA1Δ17-19 cannot interact with the partner proteins Abraxas and CtIP, thus preventing interactions known to be critical for processing of DNA lesions. We propose that the observed inability of BRCA1Δ17-19 to functionally replace wtBRCA1 in repair of DNA double-strand breaks (DDSB) reflects impaired capacity to form the BRCA1-A and -C repair complexes. Our findings indicate that expression of BRCA1Δ17-19 may negatively influence genome stability by reducing the DDSB repair velocity, thereby contributing to enhanced probability of cancer development in the affected families.
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Abstract
Breast cancer is the most common malignancy in women and a significant cause of morbidity and mortality. Sub-types of breast cancer defined by the expression of steroid hormones and Her2/Neu oncogene have distinct prognosis and undergo different therapies. Besides differing in their phenotype, sub-types of breast cancer display various molecular lesions that participate in their pathogenesis. BRCA1 is one of the common hereditary cancer predisposition genes and encodes for an ubiquitin ligase. Ubiquitin ligases or E3 enzymes participate together with ubiquitin activating enzyme and ubiquitin conjugating enzymes in the attachment of ubiquitin (ubiquitination) in target proteins. Ubiquitination is a post-translational modification regulating multiple cell functions. It also plays important roles in carcinogenesis in general and in breast carcinogenesis in particular. Ubiquitin conjugating enzymes are a central component of the ubiquitination machinery and are often perturbed in breast cancer. This paper will discuss ubiquitin and ubiquitin-like proteins conjugating enzymes participating in breast cancer pathogenesis, their relationships with other proteins of the ubiquitination machinery and their role in phenotype of breast cancer sub-types.
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Affiliation(s)
- Ioannis A Voutsadakis
- Centre Pluridisciplinaire d'Oncologie, BH06, University Hospital of Lausanne, Lausanne, Switzerland.
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Chang S, Sharan SK. The role of epigenetic transcriptional regulation in BRCA1-mediated tumor suppression. Transcription 2012; 4:24-8. [PMID: 23131665 DOI: 10.4161/trns.22600] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Mutation in BRCA1 accounts for half of all familial breast cancer cases. Recent studies have shown its role in the epigenetic regulation of an oncogenic microRNA, revealing a novel mode of tumor suppression that is independent of its well-established role in DNA repair and cell cycle regulation.
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Affiliation(s)
- Suhwan Chang
- Dept. of Medicine, Graduate School, University of Ulsan College of Medicine, Asan Institute for Life Science, Songpa-gu, Seoul, Republic of Korea
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