1
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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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2
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Biswas K, Mohammed A, Sharan SK, Shoemaker RH. Genetically engineered mouse models for hereditary cancer syndromes. Cancer Sci 2023; 114:1800-1815. [PMID: 36715493 PMCID: PMC10154891 DOI: 10.1111/cas.15737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/21/2023] [Accepted: 01/25/2023] [Indexed: 01/31/2023] Open
Abstract
Advances in molecular diagnostics have led to improved diagnosis and molecular understanding of hereditary cancers in the clinic. Improving the management, treatment, and potential prevention of cancers in carriers of predisposing mutations requires preclinical experimental models that reflect the key pathogenic features of the specific syndrome associated with the mutations. Numerous genetically engineered mouse (GEM) models of hereditary cancer have been developed. In this review, we describe the models of Lynch syndrome and hereditary breast and ovarian cancer syndrome, the two most common hereditary cancer predisposition syndromes. We focus on Lynch syndrome models as illustrative of the potential for using mouse models to devise improved approaches to prevention of cancer in a high-risk population. GEM models are an invaluable tool for hereditary cancer models. Here, we review GEM models for some hereditary cancers and their potential use in cancer prevention studies.
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Affiliation(s)
- Kajal Biswas
- Chemopreventive Agent Development Research Group, Division of Cancer Prevention, National Cancer Institute, Rockville, Maryland, USA
| | - Altaf Mohammed
- Chemopreventive Agent Development Research Group, Division of Cancer Prevention, National Cancer Institute, Rockville, Maryland, USA
| | - Shyam K Sharan
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA
| | - Robert H Shoemaker
- Chemopreventive Agent Development Research Group, Division of Cancer Prevention, National Cancer Institute, Rockville, Maryland, USA
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3
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Agaoglu NB, Unal B, Akgun Dogan O, Kanev MO, Zolfagharian P, Ozemri Sag S, Temel SG, Doganay L. Consistency of variant interpretations among bioinformaticians and clinical geneticists in hereditary cancer panels. Eur J Hum Genet 2022; 30:378-383. [PMID: 35132179 PMCID: PMC8904571 DOI: 10.1038/s41431-022-01060-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 09/19/2021] [Accepted: 01/28/2022] [Indexed: 01/12/2023] Open
Abstract
Next-generation sequencing (NGS) is used increasingly in hereditary cancer patients' (HCP) management. While enabling evaluation of multiple genes simultaneously, the technology brings to light the dilemma of variant interpretation. Here, we aimed to reveal the underlying reasons for the discrepancy in the evidence titles used during variant classification according to ACMG guidelines by two different bioinformatic specialists (BIs) and two different clinical geneticists (CGs). We evaluated final reports of 1920 cancer patients and 189 different variants from 285 HCP were enrolled to the study. A total of 173 of these variants were classified as pathogenic (n = 132) and likely pathogenic (n = 41) by the BI and an additional 16 variants, that were classified as VUS by at least one interpreter and their classification would change the clinical management, were compared for their evidence titles between different specialists. The attributed evidence titles and the final classification of the variants among BIs and CGs were compared. The discrepancy between P/LP final reports was 22.5%. The discordance between CGs was 30% whereas the discordance between two BIs was almost 75%. The use of PVS1, PS3, PP3, PP5, PM1, PM2, BP1, BP4 criteria markedly varied from one expert to another. This difference was particularly noticeable in PP3, PP5, and PM1 evidence and mostly in the variants affecting splice sites like BRCA1(NM_007294.4) c.4096 + 1 G > A and CHEK2(NM_007194.4) c.592 + 3 A > T. With recent advancements in precision medicine, the importance of variant interpretations is emerging. Our study shows that variant interpretation is subjective process that is in need of concrete definitions for accurate and standard interpretation.
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Affiliation(s)
- Nihat Bugra Agaoglu
- Department of Medical Genetics, Umraniye Training and Research Hospital, University of Health Sciences, Istanbul, Turkey.
- Genomic Laboratory (GLAB), Umraniye Training and Research Hospital, University of Health Sciences, Istanbul, Turkey.
| | - Busra Unal
- Department of Medical Genetics, Umraniye Training and Research Hospital, University of Health Sciences, Istanbul, Turkey
- Genomic Laboratory (GLAB), Umraniye Training and Research Hospital, University of Health Sciences, Istanbul, Turkey
| | - Ozlem Akgun Dogan
- Genomic Laboratory (GLAB), Umraniye Training and Research Hospital, University of Health Sciences, Istanbul, Turkey
- Department of Pediatric Genetics, Umraniye Training and Research Hospital, University of Health Sciences, Istanbul, Turkey
| | - Martin Orlinov Kanev
- Department of Biotechnology and Genetic, Institute of Science, Trakya University, Edirne, Turkey
| | - Payam Zolfagharian
- Genomic Laboratory (GLAB), Umraniye Training and Research Hospital, University of Health Sciences, Istanbul, Turkey
| | - Sebnem Ozemri Sag
- Department of Medical Genetics, Faculty of Medicine, Bursa Uludag University, Bursa, Turkey
| | - Sehime Gulsun Temel
- Department of Medical Genetics, Faculty of Medicine, Bursa Uludag University, Bursa, Turkey
- Department of Histology and Embryology, Faculty of Medicine, Bursa Uludag University, Bursa, Turkey
- Department of Translational Medicine, Institute of Health Sciences, Bursa Uludag University, Bursa, Turkey
- Department of Medical Genetics PhD. Program, Institute of Health Sciences, Faculty of Medicine, Baskent University, Ankara, Turkey
| | - Levent Doganay
- Genomic Laboratory (GLAB), Umraniye Training and Research Hospital, University of Health Sciences, Istanbul, Turkey
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4
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BRCA1/Trp53 heterozygosity and replication stress drive esophageal cancer development in a mouse model. Proc Natl Acad Sci U S A 2021; 118:2108421118. [PMID: 34607954 PMCID: PMC8521688 DOI: 10.1073/pnas.2108421118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2021] [Indexed: 12/13/2022] Open
Abstract
BRCA1 germline mutations are associated with an increased risk of breast and ovarian cancer. Recent findings of others suggest that BRCA1 mutation carriers also bear an increased risk of esophageal and gastric cancer. Here, we employ a Brca1/Trp53 mouse model to show that unresolved replication stress (RS) in BRCA1 heterozygous cells drives esophageal tumorigenesis in a model of the human equivalent. This model employs 4-nitroquinoline-1-oxide (4NQO) as an RS-inducing agent. Upon drinking 4NQO-containing water, Brca1 heterozygous mice formed squamous cell carcinomas of the distal esophagus and forestomach at a much higher frequency and speed (∼90 to 120 d) than did wild-type (WT) mice, which remained largely tumor free. Their esophageal tissue, but not that of WT control mice, revealed evidence of overt RS as reflected by intracellular CHK1 phosphorylation and 53BP1 staining. These Brca1 mutant tumors also revealed higher genome mutation rates than those of control animals; the mutational signature SBS4, which is associated with tobacco-induced tumorigenesis; and a loss of Brca1 heterozygosity (LOH). This uniquely accelerated Brca1 tumor model is also relevant to human esophageal squamous cell carcinoma, an often lethal tumor.
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5
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Ruiz de Garibay G, Fernandez-Garcia I, Mazoyer S, Leme de Calais F, Ameri P, Vijayakumar S, Martinez-Ruiz H, Damiola F, Barjhoux L, Thomassen M, Andersen LVB, Herranz C, Mateo F, Palomero L, Espín R, Gómez A, García N, Jimenez D, Bonifaci N, Extremera AI, Castaño J, Raya A, Eyras E, Puente XS, Brunet J, Lázaro C, Radice P, Barnes DR, Antoniou AC, Spurdle AB, de la Hoya M, Baralle D, Barcellos-Hoff MH, Pujana MA. Altered regulation of BRCA1 exon 11 splicing is associated with breast cancer risk in carriers of BRCA1 pathogenic variants. Hum Mutat 2021; 42:1488-1502. [PMID: 34420246 DOI: 10.1002/humu.24276] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 08/11/2021] [Accepted: 08/18/2021] [Indexed: 11/12/2022]
Abstract
Germline pathogenic variants in BRCA1 confer a high risk of developing breast and ovarian cancer. The BRCA1 exon 11 (formally exon 10) is one of the largest exons and codes for the nuclear localization signals of the corresponding gene product. This exon can be partially or entirely skipped during pre-mRNA splicing, leading to three major in-frame isoforms that are detectable in most cell types and tissue, and in normal and cancer settings. However, it is unclear whether the splicing imbalance of this exon is associated with cancer risk. Here we identify a common genetic variant in intron 10, rs5820483 (NC_000017.11:g.43095106_43095108dup), which is associated with exon 11 isoform expression and alternative splicing, and with the risk of breast cancer, but not ovarian cancer, in BRCA1 pathogenic variant carriers. The identification of this genetic effect was confirmed by analogous observations in mouse cells and tissue in which a loxP sequence was inserted in the syntenic intronic region. The prediction that the rs5820483 minor allele variant would create a binding site for the splicing silencer hnRNP A1 was confirmed by pull-down assays. Our data suggest that perturbation of BRCA1 exon 11 splicing modifies the breast cancer risk conferred by pathogenic variants of this gene.
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Affiliation(s)
- Gorka Ruiz de Garibay
- ProCURE, Oncobell, Catalan Institute of Oncology, Bellvitge Institute for Biomedical Research (IDIBELL), L'Hospitalet del Llobregat, Barcelona, Catalonia, Spain
| | - Ignacio Fernandez-Garcia
- Department of Radiation Oncology, New York University School of Medicine, New York, New York, USA
| | - Sylvie Mazoyer
- Equipe GENDEV, INSERM U1028, CNRS UMR5292, Centre de Recherche en Neurosciences de Lyon, Université Lyon 1, Université St Etienne, Lyon, France
| | - Flavia Leme de Calais
- School of Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Pietro Ameri
- Department of Radiation Oncology, New York University School of Medicine, New York, New York, USA
| | - Sangeetha Vijayakumar
- Department of Radiation Oncology, New York University School of Medicine, New York, New York, USA
| | - Haydeliz Martinez-Ruiz
- Department of Radiation Oncology, New York University School of Medicine, New York, New York, USA
| | - Francesca Damiola
- Department of Biopathology, Pathology Research Platform, Centre Léon Bérard, Lyon, France
| | - Laure Barjhoux
- Department of Biopathology, Pathology Research Platform, Centre Léon Bérard, Lyon, France
| | - Mads Thomassen
- Department of Clinical Genetics, Odense University Hospital, Odense C, Denmark
| | - Lars V B Andersen
- Department of Clinical Genetics, Odense University Hospital, Odense C, Denmark
| | - Carmen Herranz
- ProCURE, Oncobell, Catalan Institute of Oncology, Bellvitge Institute for Biomedical Research (IDIBELL), L'Hospitalet del Llobregat, Barcelona, Catalonia, Spain
| | - Francesca Mateo
- ProCURE, Oncobell, Catalan Institute of Oncology, Bellvitge Institute for Biomedical Research (IDIBELL), L'Hospitalet del Llobregat, Barcelona, Catalonia, Spain
| | - Luis Palomero
- ProCURE, Oncobell, Catalan Institute of Oncology, Bellvitge Institute for Biomedical Research (IDIBELL), L'Hospitalet del Llobregat, Barcelona, Catalonia, Spain
| | - Roderic Espín
- ProCURE, Oncobell, Catalan Institute of Oncology, Bellvitge Institute for Biomedical Research (IDIBELL), L'Hospitalet del Llobregat, Barcelona, Catalonia, Spain
| | - Antonio Gómez
- Gene Regulation, Stem Cells and Cancer, Center for Genomic Regulation (CRG), Barcelona, Catalonia, Spain
| | - Nadia García
- ProCURE, Oncobell, Catalan Institute of Oncology, Bellvitge Institute for Biomedical Research (IDIBELL), L'Hospitalet del Llobregat, Barcelona, Catalonia, Spain
| | - Daniel Jimenez
- ProCURE, Oncobell, Catalan Institute of Oncology, Bellvitge Institute for Biomedical Research (IDIBELL), L'Hospitalet del Llobregat, Barcelona, Catalonia, Spain
| | - Núria Bonifaci
- ProCURE, Oncobell, Catalan Institute of Oncology, Bellvitge Institute for Biomedical Research (IDIBELL), L'Hospitalet del Llobregat, Barcelona, Catalonia, Spain
| | - Ana I Extremera
- ProCURE, Oncobell, Catalan Institute of Oncology, Bellvitge Institute for Biomedical Research (IDIBELL), L'Hospitalet del Llobregat, Barcelona, Catalonia, Spain
| | - Julio Castaño
- Regenerative Medicine Program, Bellvitge Institute for Biomedical Research (IDIBELL) and Program for Clinical Translation of Regenerative Medicine in Catalonia (P-CMRC), L'Hospitalet del Llobregat, Barcelona, Spain
| | - Angel Raya
- Regenerative Medicine Program, Bellvitge Institute for Biomedical Research (IDIBELL) and Program for Clinical Translation of Regenerative Medicine in Catalonia (P-CMRC), L'Hospitalet del Llobregat, Barcelona, Spain.,Centre for Networked Biomedical Research on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain.,Catalan Institution for Research and Advanced Studies, Barcelona, Spain
| | - Eduardo Eyras
- Catalan Institution for Research and Advanced Studies, Barcelona, Spain.,Department of Genome Sciences, The John Curtin School of Medical Research, EMBL Australia Partner Laboratory Network, Australian National University, Canberra, Australia
| | - Xose S Puente
- Department of Biochemistry and Molecular Biology, University Institute of Oncology, University of Oviedo, Oviedo, Spain.,Biomedical Research Centre in Cancer (CIBERONC), Instituto Salud Carlos III, Madrid, Spain
| | - Joan Brunet
- Hereditary Cancer Program, Catalan Institute of Oncology, Oncobell, Bellvitge Institute for Biomedical Research (IDIBELL), L'Hospitalet del Llobregat, and Girona Biomedical Research Institute (IDIBGI), Girona, Catalonia, Spain
| | - Conxi Lázaro
- Biomedical Research Centre in Cancer (CIBERONC), Instituto Salud Carlos III, Madrid, Spain.,Hereditary Cancer Program, Catalan Institute of Oncology, Oncobell, Bellvitge Institute for Biomedical Research (IDIBELL), L'Hospitalet del Llobregat, and Girona Biomedical Research Institute (IDIBGI), Girona, Catalonia, Spain
| | -
- Unité Mixte de Génétique Constitutionnelle des Cancers Fréquents, Hospices Civils de Lyon/Centre Léon Bérard, Lyon, France
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- Department of Public Health and Primary Care, Centre for Cancer Genetic Epidemiology, University of Cambridge, Cambridge, UK
| | - Paolo Radice
- Unit of Molecular Bases of Genetic Risk and Genetic Testing, Research Department, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Daniel R Barnes
- Department of Public Health and Primary Care, Centre for Cancer Genetic Epidemiology, University of Cambridge, Cambridge, UK
| | - Antonis C Antoniou
- Department of Public Health and Primary Care, Centre for Cancer Genetic Epidemiology, University of Cambridge, Cambridge, UK
| | - Amanda B Spurdle
- Genetics and Computational Division, QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Miguel de la Hoya
- Biomedical Research Centre in Cancer (CIBERONC), Instituto Salud Carlos III, Madrid, Spain.,Molecular Oncology Laboratory, Hospital Clínico San Carlos, Health Research Institute of the Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - Diana Baralle
- School of Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, UK.,Wessex Clinical Genetics Service, Southampton University Hospital NHS Trust, Southampton, UK
| | - Mary Helen Barcellos-Hoff
- Department of Radiation Oncology, New York University School of Medicine, New York, New York, USA.,Department of Radiation Oncology, School of Medicine, University of California San Francisco, San Francisco, California, USA
| | - Miquel A Pujana
- ProCURE, Oncobell, Catalan Institute of Oncology, Bellvitge Institute for Biomedical Research (IDIBELL), L'Hospitalet del Llobregat, Barcelona, Catalonia, Spain
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6
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Mouse Models for Deciphering the Impact of Homologous Recombination on Tumorigenesis. Cancers (Basel) 2021; 13:cancers13092083. [PMID: 33923105 PMCID: PMC8123484 DOI: 10.3390/cancers13092083] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 04/19/2021] [Accepted: 04/20/2021] [Indexed: 12/15/2022] Open
Abstract
Homologous recombination (HR) is a fundamental evolutionarily conserved process that plays prime role(s) in genome stability maintenance through DNA repair and through the protection and resumption of arrested replication forks. Many HR genes are deregulated in cancer cells. Notably, the breast cancer genes BRCA1 and BRCA2, two important HR players, are the most frequently mutated genes in familial breast and ovarian cancer. Transgenic mice constitute powerful tools to unravel the intricate mechanisms controlling tumorigenesis in vivo. However, the genes central to HR are essential in mammals, and their knockout leads to early embryonic lethality in mice. Elaborated strategies have been developed to overcome this difficulty, enabling one to analyze the consequences of HR disruption in vivo. In this review, we first briefly present the molecular mechanisms of HR in mammalian cells to introduce each factor in the HR process. Then, we present the different mouse models of HR invalidation and the consequences of HR inactivation on tumorigenesis. Finally, we discuss the use of mouse models for the development of targeted cancer therapies as well as perspectives on the future potential for understanding the mechanisms of HR inactivation-driven tumorigenesis in vivo.
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7
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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: 26] [Impact Index Per Article: 6.5] [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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8
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Alternative Splicing in Breast Cancer and the Potential Development of Therapeutic Tools. Genes (Basel) 2017; 8:genes8100217. [PMID: 28981467 PMCID: PMC5664086 DOI: 10.3390/genes8100217] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 08/22/2017] [Accepted: 08/22/2017] [Indexed: 12/19/2022] Open
Abstract
Alternative splicing is a key molecular mechanism now considered as a hallmark of cancer that has been associated with the expression of distinct isoforms during the onset and progression of the disease. The leading cause of cancer-related deaths in women worldwide is breast cancer, and even when the role of alternative splicing in this type of cancer has been established, the function of this mechanism in breast cancer biology is not completely decoded. In order to gain a comprehensive view of the role of alternative splicing in breast cancer biology and development, we summarize here recent findings regarding alternative splicing events that have been well documented for breast cancer evolution, considering its prognostic and therapeutic value. Moreover, we analyze how the response to endocrine and chemical therapies could be affected due to alternative splicing and differential expression of variant isoforms. With all this knowledge, it becomes clear that targeting alternative splicing represents an innovative approach for breast cancer therapeutics and the information derived from current studies could guide clinical decisions with a direct impact in the clinical advances for breast cancer patients nowadays.
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9
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Hu J, Boritz E, Wylie W, Douek DC. Stochastic principles governing alternative splicing of RNA. PLoS Comput Biol 2017; 13:e1005761. [PMID: 28910283 PMCID: PMC5614656 DOI: 10.1371/journal.pcbi.1005761] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 09/26/2017] [Accepted: 09/03/2017] [Indexed: 12/18/2022] Open
Abstract
The dominance of the major transcript isoform relative to other isoforms from the same gene generated by alternative splicing (AS) is essential to the maintenance of normal cellular physiology. However, the underlying principles that determine such dominance remain unknown. Here, we analyzed the physical AS process and found that it can be modeled by a stochastic minimization process, which causes the scaled expression levels of all transcript isoforms to follow the same Weibull extreme value distribution. Surprisingly, we also found a simple equation to describe the median frequency of transcript isoforms of different dominance. This two-parameter Weibull model provides the statistical distribution of all isoforms of all transcribed genes, and reveals that previously unexplained observations concerning relative isoform expression derive from these principles. Alternative RNA splicing within eukaryotic cells enables each gene to generate multiple different mature transcripts which further encode proteins with distinct or even opposing functions. The relative frequencies of the transcript isoforms generated by a particular gene are essential to the maintenance of normal cellular physiology; however, the underlying mechanisms and principles that govern these frequencies are unknown. We analyzed the frequency distribution of all transcript isoforms in highly purified human T cell subsets and built a simple mathematical model, based on the physical process of alternative splicing, which provides statistical principles that govern this process. This model matches very well with the observed distributions of expression levels and relative frequencies of all transcript isoforms from different tissues and cell lines. Notably, we used this model to elucidate many previously unexplained observations concerning transcript isoform expression. More importantly, this model reveals the existence of simple statistical principles that can be applied to understanding an essential and complex biological process such as alternative splicing.
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Affiliation(s)
- Jianfei Hu
- Genome Analysis Core, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: (JH); (DCD)
| | - Eli Boritz
- Human Immunology Section, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - William Wylie
- Human Immunology Section, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Daniel C. Douek
- Genome Analysis Core, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- Human Immunology Section, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: (JH); (DCD)
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10
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MicroRNA-206 is differentially expressed in Brca1-deficient mice and regulates epithelial and stromal cell compartments of the mouse mammary gland. Oncogenesis 2016; 5:e218. [PMID: 27043663 PMCID: PMC4848838 DOI: 10.1038/oncsis.2016.27] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 01/28/2016] [Accepted: 02/10/2016] [Indexed: 12/14/2022] Open
Abstract
Depletion of Brca1 leads to defects in mouse mammary gland development and mammary tumors in humans and mice. To explore the role of microRNAs (miRNAs) in this process, we examined the mammary glands of MMTV-Cre Brca1Co/Co mice for differential miRNA expression using a candidate approach. Several miRNAs were differentially expressed in mammary tissue at day 1 of lactation and in mammary epithelial cell lines in which Brca1 messenger RNA (mRNA) levels have been reduced. Functional studies revealed that several of these miRNAs regulate mammary epithelial cell function in vitro, including miR-206. Creation and analysis of MMTV-miR-206 transgenic mice showed no effect on lactational mammary development and no tumors, but indicates a role in mammary tissue remodeling in mature mice, potentially involving Igf-1 and Sfrp1. These results indicate the potential of miRNAs to mediate the consequences of Brca1 loss and suggest a novel function for miR-206.
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11
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Wiener D, Gajardo-Meneses P, Ortega-Hernández V, Herrera-Cares C, Díaz S, Fernández W, Cornejo V, Gamboa J, Tapia T, Alvarez C, Carvallo P. BRCA1 and BARD1 colocalize mainly in the cytoplasm of breast cancer tumors, and their isoforms show differential expression. Breast Cancer Res Treat 2015; 153:669-78. [PMID: 26395808 DOI: 10.1007/s10549-015-3575-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 09/15/2015] [Indexed: 12/13/2022]
Abstract
BRCA1 has been found to be absent or miss localized in the cytoplasm in a relevant proportion of breast cancer tumors with no germline mutations. BRCA1 main function is in the nucleus, and its interaction with BARD1 is relevant for its nuclear translocation and retention. Our aim was to analyze the sub-cellular localization of BRCA1 and BARD1 in breast cancer tumors, and determine the level of expression of their splice variants BRCA1-Δ11q and BARD1-α and BARD1-β. BRCA1 and BARD1 expressions were performed by immunohistochemistry and immunofluorescence in 103 breast cancer tumors. Colocalization was determined by confocal microscopy. Transcript variants were determined by qRT-PCR. We found BRCA1 localized in the cytoplasm with BARD1 in 51.4 % of tumors. An exclusive nuclear localization of both proteins was observed in 7/103 tumors (6.8 %). Indeed, these tumors displayed an apparent nucleolar colocalization of BARD1 and BRCA1. In relation to splice variants, there is a tendency to an overexpression of BARD1-α mRNA (30 % of tumors) and a decreased expression of BARD1-β (41 %). BRCA1 full-length was downregulated in 63 % of tumors, and 37 % showed BRCA1-Δ11q variant overexpressed. Our findings contribute to a better understanding of the expression and sub-cellular localization of BRCA1 in breast cancer tumors. Interaction of BRCA1 and BARD1 seems to be not affected in 58.2 % of tumors, which showed colocalization of both proteins. The absence of BRCA1 in 41 % of tumors reveals a BRCAness phenotype, constituting an excellent marker for therapy sensitivity, to platinum drugs or PARP inhibitors.
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Affiliation(s)
- David Wiener
- Laboratory of Human Molecular Genetics, Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Portugal 49 3rd floor, Postal code 8330025, Santiago, Chile
| | - Patricia Gajardo-Meneses
- Laboratory of Human Molecular Genetics, Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Portugal 49 3rd floor, Postal code 8330025, Santiago, Chile
| | - Victoria Ortega-Hernández
- Laboratory of Human Molecular Genetics, Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Portugal 49 3rd floor, Postal code 8330025, Santiago, Chile
| | - Cristóbal Herrera-Cares
- Laboratory of Human Molecular Genetics, Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Portugal 49 3rd floor, Postal code 8330025, Santiago, Chile
| | - Sebastián Díaz
- Laboratory of Human Molecular Genetics, Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Portugal 49 3rd floor, Postal code 8330025, Santiago, Chile
| | - Wanda Fernández
- Unidad de Anatomía Patológica, Hospital Clínico San Borja Arriarán, Santiago, Chile
| | - Valeria Cornejo
- Unidad de Anatomía Patológica, Hospital Clínico San Borja Arriarán, Santiago, Chile
| | - Jorge Gamboa
- Unidad de Patología Mamaria, Hospital Clínico San Borja Arriarán, Santiago, Chile
| | - Teresa Tapia
- Laboratory of Human Molecular Genetics, Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Portugal 49 3rd floor, Postal code 8330025, Santiago, Chile
| | - Carolina Alvarez
- Laboratory of Human Molecular Genetics, Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Portugal 49 3rd floor, Postal code 8330025, Santiago, Chile
| | - Pilar Carvallo
- Laboratory of Human Molecular Genetics, Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Portugal 49 3rd floor, Postal code 8330025, Santiago, Chile.
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12
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A Mouse Model That Reproduces the Developmental Pathways and Site Specificity of the Cancers Associated With the Human BRCA1 Mutation Carrier State. EBioMedicine 2015; 2:1318-30. [PMID: 26629527 PMCID: PMC4634618 DOI: 10.1016/j.ebiom.2015.08.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 08/22/2015] [Accepted: 08/26/2015] [Indexed: 12/11/2022] Open
Abstract
Predisposition to breast and extrauterine Müllerian carcinomas in BRCA1 mutation carriers is due to a combination of cell-autonomous consequences of BRCA1 inactivation on cell cycle homeostasis superimposed on cell-nonautonomous hormonal factors magnified by the effects of BRCA1 mutations on hormonal changes associated with the menstrual cycle. We used the Müllerian inhibiting substance type 2 receptor (Mis2r) promoter and a truncated form of the Follicle stimulating hormone receptor (Fshr) promoter to introduce conditional knockouts of Brca1 and p53 not only in mouse mammary and Müllerian epithelia, but also in organs that control the estrous cycle. Sixty percent of the double mutant mice developed invasive Müllerian and mammary carcinomas. Mice carrying heterozygous mutations in Brca1 and p53 also developed invasive tumors, albeit at a lesser (30%) rate, in which the wild type alleles were no longer present due to loss of heterozygosity. While mice carrying heterozygous mutations in both genes developed mammary tumors, none of the mice carrying only a heterozygous p53 mutation developed such tumors (P < 0.0001), attesting to a role for Brca1 mutations in tumor development. This mouse model is attractive to investigate cell-nonautonomous mechanisms associated with cancer predisposition in BRCA1 mutation carriers and to investigate the merit of chemo-preventive drugs targeting such mechanisms. Mouse model reproducing both, cell-autonomous and cell-nonautonomous mechanisms of cancer risk in BRCA1 mutation carriers. The Müllerian and mesonephric ducts are embryologically linked, possibly accounting for Müllerian clear cell carcinomas. Foci of endosalpingiosis are at increased risk of cancer in the absence of a functional Brca1.
Most individuals with familial predisposition to breast and ovarian cancer carry germline mutations in BRCA1. Cancer predisposition in such carriers is due not only to effects of these mutations in tissues with an elevated cancer risk, but also in organs that control the menstrual cycle, which influences such tissues. The animal model that we developed mimics both mechanisms, which will facilitate our understanding of the contribution of menstrual cycle regulation to risk of these cancers. Our characterization of this model also led to insights into the origin of the serous and clear cell subtypes of ovarian cancer.
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Tammaro C, Raponi M, Wilson DI, Baralle D. BRCA1 EXON 11, a CERES (composite regulatory element of splicing) element involved in splice regulation. Int J Mol Sci 2014; 15:13045-59. [PMID: 25056543 PMCID: PMC4139890 DOI: 10.3390/ijms150713045] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Revised: 06/17/2014] [Accepted: 07/04/2014] [Indexed: 11/16/2022] Open
Abstract
Unclassified variants (UV) of BRCA1 can affect normal pre-mRNA splicing. Here, we investigate the UV c.693G>A, a "silent" change in BRCA1 exon 11, which we have found induces aberrant splicing in patient carriers and in vitro. Using a minigene assay, we show that the UV c.693G>A has a strong effect on the splicing isoform ratio of BRCA1. Systematic site-directed mutagenesis of the area surrounding the nucleotide position c.693G>A induced variable changes in the level of exon 11 inclusion/exclusion in the mRNA, pointing to the presence of a complex regulatory element with overlapping enhancer and silencer functions. Accordingly, protein binding analysis in the region detected several splicing regulatory factors involved, including SRSF1, SRSF6 and SRSF9, suggesting that this sequence represents a composite regulatory element of splicing (CERES).
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Affiliation(s)
- Claudia Tammaro
- Human Development and Health, University of Southampton, Southampton SO16 6YD, UK.
| | - Michela Raponi
- Human Development and Health, University of Southampton, Southampton SO16 6YD, UK.
| | - David I Wilson
- Human Development and Health, University of Southampton, Southampton SO16 6YD, UK.
| | - Diana Baralle
- Human Development and Health, University of Southampton, Southampton SO16 6YD, UK.
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14
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Wang L, Di LJ. BRCA1 and estrogen/estrogen receptor in breast cancer: where they interact? Int J Biol Sci 2014; 10:566-75. [PMID: 24910535 PMCID: PMC4046883 DOI: 10.7150/ijbs.8579] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 03/24/2014] [Indexed: 01/08/2023] Open
Abstract
BRCA1 mainly acts as a tumor suppressor and BRCA1 mutation correlates with increased cancer risk. Although it is well recognized that BRCA1 related tumorigenesis is mainly caused by the increased DNA damage and decreased genome stability, it is not clear that why BRCA1 related patients have higher risk for cancer development mainly in estrogen responsive tissues such as breast and ovary. Recent studies suggested that BRCA1 and E-ER (estrogen and estrogen receptor) signaling synergistically regulate the mammary epithelial cell proliferation and differentiation. In this current presentation, we reviewed the correlation between mammary gland epithelial cell transformation and the status of BRCA1 and ER. Then the mechanisms of BRCA1 and E-ER interaction at both gene transcription level and protein-protein interaction level are discussed. Furthermore, the tumorigenic mechanisms are discussed by focusing on the synergistic effect of BRCA1 and E-ER on cell metabolism, ROS management, and antioxidant activity in mammary gland epithelial cells. Also, the possibility of cell de-differentiation promoted by coordinated effect between BRCA1 mutation and E-ER signal is explored. Together, the currently available evidences suggest that BRCA1 mutation and E-ER signal together, contribute to breast tumorigenesis by providing the metabolic support for cancer cell growth and even may directly be involved in promoting the de-differentiation of cancer-prone epithelial cells.
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Affiliation(s)
- Li Wang
- Faculty of health sciences, University of Macau, SAR of People's Republic of China
| | - Li-Jun Di
- Faculty of health sciences, University of Macau, SAR of People's Republic of China
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15
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Abstract
Germline mutations of human breast cancer-associated gene 1 (BRCA1) predispose women to breast and ovarian cancers. In mice, over 20 distinct mutations, including null, hypomorphic, isoform, conditional, and point mutations, have been created to study functions of Brca1 in mammary development and tumorigenesis. Analyses using these mutant mice have yielded an enormous amount of information that greatly facilitates our understanding of the gender- and tissue-specific tumor suppressor functions of BRCA1, as well as enriches our insights into applying these preclinical models of disease to breast cancer research. Here, we review features of these mutant mice and their applications to cancer prevention and therapeutic treatment.
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16
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BRCA1 exon 11 alternative splicing, multiple functions and the association with cancer. Biochem Soc Trans 2012; 40:768-72. [PMID: 22817731 DOI: 10.1042/bst20120140] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BRCA1 (breast cancer early-onset 1) alternative splicing levels are regulated in a cell-cycle- and cell-type-specific manner, with splice variants being present in different proportions in tumour cell lines as well as in normal mammary epithelial cells. The importance of this difference in the pathogenesis of breast cancer has yet to be determined. Developing an understanding of the impact of BRCA1 isoform ratio changes on cell phenotype will be of value in breast cancer and may offer therapeutic options. In the present paper, we describe the splicing isoforms of BRCA1 exon 11, their possible role in cancer biology and the importance of maintaining a balanced ratio.
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Yoon S, Yi YS, Kim SS, Kim JH, Park WS, Nam SW. SOCS5 and SOCS6 have similar expression patterns in normal and cancer tissues. Tumour Biol 2011; 33:215-21. [DOI: 10.1007/s13277-011-0264-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Accepted: 10/27/2011] [Indexed: 12/31/2022] Open
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18
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Li H, Sekine M, Tung N, Avraham HK. Wild-type BRCA1, but not mutated BRCA1, regulates the expression of the nuclear form of beta-catenin. Mol Cancer Res 2010; 8:407-20. [PMID: 20215423 DOI: 10.1158/1541-7786.mcr-09-0403] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BRCA1 is an essential caretaker protein in the surveillance of DNA damage, is mutated in approximately 50% of all hereditary breast cancer cases, and its expression is frequently decreased in sporadic breast cancer. beta-Catenin is a multifunctional protein that forms adhesion complex with E-cadherins, alpha-catenin, and actin, and plays a central role in Wnt signaling through its nuclear translocation and activation of beta-catenin-responsive genes. Although significant progress has been made in understanding the Wnt/beta-catenin and BRCA1 signaling cascades, it is not known whether there is a link between beta-catenin and BRCA1. We observed that the expression of the active nuclear form of beta-catenin (also known as ABC, Ser37/Thr41-nonphosphorylated beta-catenin, dephosphorylated beta-catenin) was lower or absent in the nucleus in most BRCA1 familial breast cancer tissues (17 cases) compared with sporadic breast cancer (14 samples) and normal breast tissues. Wild-type-BRCA1, but not mutated BRCA1, interacted with beta-catenin and increased the levels of beta-catenin protein expression in vitro. Furthermore, H(2)O(2) induced the interaction of the nuclear form of beta-catenin with BRCA1. The active form of beta-catenin protein was downregulated upon exposure to H(2)O(2) in the nucleus of BRCA1-deficient HCC1937 breast cancer cells, whereas reconstitution of WT-BRCA1 in HCC1937 cells inhibited this downregulation. This study provides evidence of a novel interaction between BRCA1 and beta-catenin, and that loss of BRCA1 leads to impaired expression of the nuclear form of beta-catenin, which may contribute to the pathogenesis of breast cancer.
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Affiliation(s)
- Huchun Li
- Division of Experimental Medicine, Beth Israel Deaconess Medical Center, Harvard Institutes of Medicine, 99 Brookline Avenue, RN-330C, Boston, MA 02115, USA
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Kim SS, Cao L, Baek HJ, Lim SC, Li C, Wang RH, Xu X, Cho KH, Deng CX. Impaired skin and mammary gland development and increased gamma-irradiation-induced tumorigenesis in mice carrying a mutation of S1152-ATM phosphorylation site in Brca1. Cancer Res 2009; 69:9291-300. [PMID: 19996295 PMCID: PMC2795111 DOI: 10.1158/0008-5472.can-09-2418] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The tumor suppressor BRCA1 interacts with many proteins and undergoes multiple modifications on DNA damage. ATM, a key molecule of the DNA damage response, phosphorylates S1189 of BRCA1 after gamma-irradiation. S1189 of BRCA1 is known as a unique ATM phosphorylation site in BRCA1 exon 11. To study the functions of ATM-dependent phosphorylation of BRCA1-S1189, we generated a mouse model carrying a mutation of S1152A (S1152 in mouse Brca1 corresponds to S1189 in human BRCA1) by gene targeting. Brca1(S1152A/S1152A) mice were born at the expected ratio, unlike that seen in previous studies of Brca1-null mice. However, 36% of Brca1(S1152A/S1152A) mice exhibited aging-like phenotypes including growth retardation, skin abnormalities, and delay of the mammary gland morphogenesis, with an increase in apoptosis. Mutant mice were hypersensitive to high doses of gamma-irradiation, displaying shortened life span and reduction in intestinal villus size, associated with increased apoptosis. Aging-unaffected 18-month-old Brca1(S1152A/S1152A) female mice also showed mammary gland abnormalities with increased levels of cyclin D1 and phospho-ER-alpha, such as Brca1-Delta11 mutation. On low-dose gamma-irradiation, they suffered a marked increase in tumor formation with an abnormal coat pattern. Furthermore, Brca1(S1152A/S1152A) embryonic fibroblasts failed to accumulate p53 on gamma-irradiation with delayed phosphorylation of p53-S23. These observations indicate that ATM-mediated phosphorylation of S1189 is required for BRCA1 functions in the modulation of DNA damage response and in the suppression of tumor formation by regulating p53 and apoptosis.
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Affiliation(s)
- Sang Soo Kim
- Radiation Medicine Branch, National Cancer Center, Goyang, 410-769, Korea
- Genetics of Development and Disease Branch, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, 10/9N105, 10 Center Drive, Bethesda, MD 20892, USA
- Address correspondence to: Sang Soo Kim, Phone: (8231) 920-2491, Fax: (8231) 920-2494, , Chu-Xia Deng, Phone: (301) 402-7225, Fax: (301) 480-1135,
| | - Liu Cao
- Genetics of Development and Disease Branch, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, 10/9N105, 10 Center Drive, Bethesda, MD 20892, USA
| | - Hye Jung Baek
- Radiation Medicine Branch, National Cancer Center, Goyang, 410-769, Korea
| | - Sung-Chul Lim
- Department of Pathology, College of Medicine, Chosun University, Gwangju, 501-759, Korea
| | - Cuiling Li
- Genetics of Development and Disease Branch, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, 10/9N105, 10 Center Drive, Bethesda, MD 20892, USA
| | - Rui-Hong Wang
- Genetics of Development and Disease Branch, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, 10/9N105, 10 Center Drive, Bethesda, MD 20892, USA
| | - Xiaoling Xu
- Genetics of Development and Disease Branch, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, 10/9N105, 10 Center Drive, Bethesda, MD 20892, USA
| | - Kwan Ho Cho
- Radiation Medicine Branch, National Cancer Center, Goyang, 410-769, Korea
| | - Chu-Xia Deng
- Genetics of Development and Disease Branch, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, 10/9N105, 10 Center Drive, Bethesda, MD 20892, USA
- Address correspondence to: Sang Soo Kim, Phone: (8231) 920-2491, Fax: (8231) 920-2494, , Chu-Xia Deng, Phone: (301) 402-7225, Fax: (301) 480-1135,
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20
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Xing D, Scangas G, Nitta M, He L, Xu X, Ioffe YJM, Aspuria PJ, Hedvat CY, Anderson ML, Oliva E, Karlan BY, Mohapatra G, Orsulic S. A role for BRCA1 in uterine leiomyosarcoma. Cancer Res 2009; 69:8231-5. [PMID: 19843854 DOI: 10.1158/0008-5472.can-09-2543] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Uterine leiomyosarcoma (ULMS) is a rare gynecologic malignancy with a low survival rate. Currently, there is no effective treatment for ULMS. Infrequent occurrences of human ULMS hamper the understanding of the initiation and progression of the disease, thereby limiting the ability to develop efficient therapies. To elucidate the roles of the p53 and BRCA1 tumor suppressor genes in gynecologic malignancies, we generated mice in which p53 and/or BRCA1 can be conditionally deleted using anti-Müllerian hormone type II receptor (Amhr2)-driven Cre recombinase. We showed that conditional deletion of p53 in mice results in the development of uterine tumors that resemble human ULMS and that concurrent deletion of p53 and BRCA1 significantly accelerates the progression of these tumors. This finding led to our hypothesis that BRCA1 may play a role in human ULMS development. Consistent with this hypothesis, we showed that the BRCA1 protein is absent in 29% of human ULMS and that BRCA1 promoter methylation is the likely mechanism of BRCA1 downregulation. These data indicate that the loss of BRCA1 function may be an important step in the progression of ULMS. Our findings provide a rationale for investigating therapies that target BRCA1 deficiency in ULMS.
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Affiliation(s)
- Deyin Xing
- Molecular Pathology Unit and Center for Cancer Research, Massachusetts General Hospital, Charlestown, Massachusetts, USA
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21
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Abstract
A substantial part of all hereditary breast cancer cases is caused by BRCA1 germline mutations. In this review, we will discuss the insights into BRCA1 functions that we obtained from mouse models with conventional and conditional mutations in Brca1. The most advanced models closely resemble human BRCA1-related breast cancer and may therefore be useful for addressing clinically relevant questions.
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22
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Georgakilas AG, Aziz K, Ziech D, Georgakila S, Panayiotidis MI. BRCA1 involvement in toxicological responses and human cancer etiology. Toxicol Lett 2009; 188:77-83. [PMID: 19375487 DOI: 10.1016/j.toxlet.2009.04.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2009] [Revised: 04/03/2009] [Accepted: 04/06/2009] [Indexed: 11/18/2022]
Abstract
Breast cancer associated gene 1 (BRCA1) gene is located on the long (q) arm of chromosome 17 at position 21. In the nucleus of many types of normal cells, BRCA1 protein interacts with several other proteins to mend strand breaks in DNA. It is generally considered a key regulatory protein participating in cell cycle checkpoint and DNA damage repair networks. Exposure to various environmental and genetic factors can induce a severe impact on life span and lead to neoplastic transformation. BRCA1 through its participation in the control mechanisms of cell growth and DNA repair is lately considered as an important component of mammary homeostasis. In this review we summarize the different cellular functions and roles of this gene, the experimental evidence for its linkage to carcinogenesis and recent evidence tying BRCA1 to environmentally induced toxic-stress responses. Finally, we discuss the new insights in the exploitation of BRCA1 defects for the development of new therapeutic strategies in cancer treatment and clinical applications.
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Affiliation(s)
- Alexandros G Georgakilas
- Department of Biology, Thomas Harriot College of Arts and Sciences, East Carolina University, Greenville, NC 27858, USA.
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23
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Reddy NM, Kleeberger SR, Bream JH, Fallon PG, Kensler TW, Yamamoto M, Reddy SP. Genetic disruption of the Nrf2 compromises cell-cycle progression by impairing GSH-induced redox signaling. Oncogene 2008; 27:5821-32. [PMID: 18542053 PMCID: PMC2646365 DOI: 10.1038/onc.2008.188] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2007] [Revised: 05/05/2008] [Accepted: 05/12/2008] [Indexed: 01/10/2023]
Abstract
Genetic disruption of Nrf2 greatly enhances susceptibility to prooxidant- and carcinogen-induced experimental models of various human disorders; but the mechanisms by which this transcription factor confers protection are unclear. Using Nrf2-proficient (Nrf2(+/+)) and Nrf2-deficient (Nrf2(-/-)) primary epithelial cultures as a model, we now show that Nrf2 deficiency leads to oxidative stress and DNA lesions, accompanied by impairment of cell-cycle progression, mainly G(2)/M-phase arrest. Both N-acetylcysteine and glutathione (GSH) supplementation ablated the DNA lesions and DNA damage-response pathways in Nrf2(-/-) cells; however only GSH could rescue the impaired colocalization of mitosis-promoting factors and the growth arrest. Akt activation was deregulated in Nrf2(-/-) cells, but GSH supplementation restored it. Inhibition of Akt signaling greatly diminished the GSH-induced Nrf2(-/-) cell proliferation and wild-type cell proliferation. GSH depletion impaired Akt signaling and mitosis-promoting factor colocalization in Nrf2(+/+) cells. Collectively, our findings uncover novel functions for Nrf2 in regulating oxidative stress-induced cell-cycle arrest, especially G(2)/M-checkpoint arrest, and proliferation, and GSH-regulated redox signaling and Akt are required for this process.
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Affiliation(s)
- NM Reddy
- Department of Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - SR Kleeberger
- National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
| | - JH Bream
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - PG Fallon
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - TW Kensler
- Department of Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - M Yamamoto
- Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - SP Reddy
- Department of Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
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Baek HJ, Lim SC, Kitisin K, Jogunoori W, Tang Y, Marshall MB, Mishra B, Kim TH, Cho KH, Kim SS, Mishra L. Hepatocellular cancer arises from loss of transforming growth factor beta signaling adaptor protein embryonic liver fodrin through abnormal angiogenesis. Hepatology 2008; 48:1128-37. [PMID: 18704924 PMCID: PMC2747753 DOI: 10.1002/hep.22460] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
UNLABELLED We have previously demonstrated that 40%-70% of elf(+/-) mice spontaneously develop hepatocellular cancer (HCC) within 15 months, revealing the importance of the transforming growth factor-beta (TGF-beta) signaling pathway in suppressing tumorigenesis in the liver. The current study was carried out to investigate mechanisms by which embryonic liver fodrin (ELF), a crucial Smad3/4 adaptor, suppresses liver tumor formation. Histological analysis of hyperplastic liver tissues from elf(+/-) mice revealed abundant newly formed vascular structures, suggesting aberrant angiogenesis with loss of ELF function. In addition, elf(+/-) mice displayed an expansion of endothelial progenitor cells. Ectopic ELF expression in fetal bovine heart endothelial (FBHE) cells resulted in cell cycle arrest and apoptosis. Further analysis of developing yolk sacs of elf(-/-) mice revealed a failure of normal vasculature and significantly decreased endothelial cell differentiation with embryonic lethality. Immunohistochemical analysis of hepatocellular cancer (HCC) from the elf(+/-) mice revealed an abnormal angiogenic profile, suggesting the role of ELF as an angiogenic regulator in suppressing HCC. Lastly, acute small interfering RNA (siRNA) inhibition of ELF raised retinoblastoma protein (pRb) levels nearly fourfold in HepG2 cells (a hepatocellular carcinoma cell line) as well as in cow pulmonary artery endothelial (CPAE) cells, respectively. CONCLUSION Taken together these results, ELF, a TGF-beta adaptor and signaling molecule, functions as a critical adaptor protein in TGF-beta modulation of angiogenesis as well as cell cycle progression. Loss of ELF in the liver leads the cancer formation by deregulated hepatocyte proliferation and stimulation of angiogenesis in early cancers. Our studies propose that ELF is potentially a powerful target for mimetics enhancing the TGF-beta pathway tumor suppression of HCC.
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Affiliation(s)
- Hye Jung Baek
- Radiation Medicine Branch, National Cancer Center, Goyang, Korea
| | - Sung Chul Lim
- Department of Pathology, Research Center for Resistant Cells, College of Medicine, Chosun University, Gwangju, Korea
| | - Krit Kitisin
- Department of Surgery, Laboratory of Cancer Genetics, Digestive Diseases, and Developmental Molecular Biology, Lombardi Cancer Center, Georgetown University, Washington, DC
| | - Wilma Jogunoori
- Department of Surgery, Laboratory of Cancer Genetics, Digestive Diseases, and Developmental Molecular Biology, Lombardi Cancer Center, Georgetown University, Washington, DC
| | - Yi Tang
- Department of Surgery, Laboratory of Cancer Genetics, Digestive Diseases, and Developmental Molecular Biology, Lombardi Cancer Center, Georgetown University, Washington, DC
| | - M. Blair Marshall
- Department of Surgery, Laboratory of Cancer Genetics, Digestive Diseases, and Developmental Molecular Biology, Lombardi Cancer Center, Georgetown University, Washington, DC
| | - Bibhuti Mishra
- Department of Surgery, Laboratory of Cancer Genetics, Digestive Diseases, and Developmental Molecular Biology, Lombardi Cancer Center, Georgetown University, Washington, DC
| | - Tae Hyun Kim
- Radiation Medicine Branch, National Cancer Center, Goyang, Korea
| | - Kwan Ho Cho
- Radiation Medicine Branch, National Cancer Center, Goyang, Korea
| | - Sang Soo Kim
- Radiation Medicine Branch, National Cancer Center, Goyang, Korea
| | - Lopa Mishra
- Department of Surgery, Laboratory of Cancer Genetics, Digestive Diseases, and Developmental Molecular Biology, Lombardi Cancer Center, Georgetown University, Washington, DC
- Department of Veterans Affairs, Washington, DC
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Baek HJ, Kim TH, Shin D, Kwak JW, Choo DW, Lee SB, Furusawa Y, Ando K, Kim SS, Cho KH. Radiobiological characterization of proton beam at the National Cancer Center in Korea. JOURNAL OF RADIATION RESEARCH 2008; 49:509-515. [PMID: 18567940 DOI: 10.1269/jrr.08017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Estimation of the relative biological effectiveness (RBE) of the proton beam at the National Cancer Center Proton Therapy Center in Korea (NCCPTC) is required clinically for the treatment of cancer. The proton beam was fixed at 190 MeV with 6 cm a spread out Bragg peaks (SOBP) for which corresponds to most frequent clinical condition. The RBE was estimated from the survival of human salivary gland (HSG) cells using the traditional colonogenic and MTT assays. The HSG cells were also irradiated in a cell-stack chamber and monitored for survival to identify whether the characteristic depth-dependent survival pattern was observed. The RBE of the NCCPTC was estimated to be 1.024 +/- 0.007 and 1.049 +/- 0.028 at the middle of SOBP using colonogenic and MTT assays, respectively. Further analysis of the biological response of proton exposure revealed no difference compared to conventional X-ray treatment in western blot, and FACS analysis. The proton beam of the NCCPTC also exhibited the characteristic depth-dependent survival pattern. The estimated RBE value of NCCPTC was slightly smaller than generic RBE value of 1.1 for protons of the majority of centers. Due to the recommendation of a generic RBE of 1.1 for protons, a representative RBE value of 1.1 was assigned for clinical application for proton beams at the NCCPTC.
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Affiliation(s)
- Hye-Jung Baek
- Radiation Medicine Branch, National Cancer Center, Goyang, Korea
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