1
|
Yue W, Ma J, Xiao Y, Wang P, Gu X, Xie B, Li M. The Apoptotic Resistance of BRCA1-Deficient Ovarian Cancer Cells is Mediated by cAMP. Front Cell Dev Biol 2022; 10:889656. [PMID: 35517499 PMCID: PMC9065249 DOI: 10.3389/fcell.2022.889656] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 03/23/2022] [Indexed: 11/17/2022] Open
Abstract
Breast cancer type 1 susceptibility protein (BRCA1) is essential for homologous recombination repair of DNA double-strand breaks. Loss of BRCA1 is lethal to embryos due to extreme genomic instability and the activation of p53-dependent apoptosis. However, the apoptosis is resisted in BRCA1-deficient cancer cells even though their p53 is proficient. In this study, by analysis of transcriptome data of ovarian cancer patients bearing BRCA1 defects in TCGA database, we found that cAMP signaling pathway was significantly activated. Experimentally, we found that BRCA1 deficiency caused an increased expression of ADRB1, a transmembrane receptor that can promote the generation of cAMP. The elevated cAMP not only inhibited DNA damage-induced apoptosis through abrogating p53 accumulation, but also suppressed the proliferation of cytotoxic T lymphocytes by enhancing the expression of immunosuppressive factors DKK1. Inhibition of ADRB1 effectively killed cancer cells by abolishing the apoptotic resistance. These findings uncover a novel mechanism of apoptotic resistance in BRCA1-deficient ovarian cancer cells and point to a potentially new strategy for treating BRCA1-mutated tumors.
Collapse
Affiliation(s)
- Wei Yue
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China
- National Clinical Research Center for Obstetrics and Gynecology (Peking University Third Hospital), Beijing, China
- Key Laboratory of Assisted Reproduction (Peking University), Ministry of Education, Beijing, China
- Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology (Peking University Third Hospital), Beijing, China
| | - Jihong Ma
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China
- National Clinical Research Center for Obstetrics and Gynecology (Peking University Third Hospital), Beijing, China
- Key Laboratory of Assisted Reproduction (Peking University), Ministry of Education, Beijing, China
- Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology (Peking University Third Hospital), Beijing, China
| | - Yinan Xiao
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China
- National Clinical Research Center for Obstetrics and Gynecology (Peking University Third Hospital), Beijing, China
- Key Laboratory of Assisted Reproduction (Peking University), Ministry of Education, Beijing, China
- Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology (Peking University Third Hospital), Beijing, China
| | - Pan Wang
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China
- National Clinical Research Center for Obstetrics and Gynecology (Peking University Third Hospital), Beijing, China
- Key Laboratory of Assisted Reproduction (Peking University), Ministry of Education, Beijing, China
- Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology (Peking University Third Hospital), Beijing, China
| | - Xiaoyang Gu
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China
- National Clinical Research Center for Obstetrics and Gynecology (Peking University Third Hospital), Beijing, China
- Key Laboratory of Assisted Reproduction (Peking University), Ministry of Education, Beijing, China
- Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology (Peking University Third Hospital), Beijing, China
| | - Bingteng Xie
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Mo Li
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China
- National Clinical Research Center for Obstetrics and Gynecology (Peking University Third Hospital), Beijing, China
- Key Laboratory of Assisted Reproduction (Peking University), Ministry of Education, Beijing, China
- Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology (Peking University Third Hospital), Beijing, China
- *Correspondence: Mo Li,
| |
Collapse
|
2
|
Lei JH, Lee M, Miao K, Huang Z, Yao Z, Zhang A, Xu J, Zhao M, Huang Z, Zhang X, Chen S, Jiaying NG, Feng Y, Xing F, Chen P, Sun H, Chen Q, Xiang T, Chen L, Xu X, Deng C. Activation of FGFR2 Signaling Suppresses BRCA1 and Drives Triple-Negative Mammary Tumorigenesis That is Sensitive to Immunotherapy. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2100974. [PMID: 34514747 PMCID: PMC8564435 DOI: 10.1002/advs.202100974] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 07/08/2021] [Indexed: 06/13/2023]
Abstract
Fibroblast growth factor receptor 2 (FGFR2) is a membrane-spanning tyrosine kinase that mediates FGF signaling. Various FGFR2 alterations are detected in breast cancer, yet it remains unclear if activation of FGFR2 signaling initiates tumor formation. In an attempt to answer this question, a mouse model berrying an activation mutation of FGFR2 (FGFR2-S252W) in the mammary gland is generated. It is found that FGF/FGFR2 signaling drives the development of triple-negative breast cancer accompanied by epithelial-mesenchymal transition that is regulated by FGFR2-STAT3 signaling. It is demonstrated that FGFR2 suppresses BRCA1 via the ERK-YY1 axis and promotes tumor progression. BRCA1 knockout in the mammary gland of the FGFR2-S252W mice significantly accelerated tumorigenesis. It is also shown that FGFR2 positively regulates PD-L1 and that a combination of FGFR2 inhibition and immune checkpoint blockade kills cancer cells. These data suggest that the mouse models mimic human breast cancers and can be used to identify actionable therapeutic targets.
Collapse
|
3
|
Hámori L, Kudlik G, Szebényi K, Kucsma N, Szeder B, Póti Á, Uher F, Várady G, Szüts D, Tóvári J, Füredi A, Szakács G. Establishment and Characterization of a Brca1 -/-, p53 -/- Mouse Mammary Tumor Cell Line. Int J Mol Sci 2020; 21:ijms21041185. [PMID: 32053991 PMCID: PMC7072850 DOI: 10.3390/ijms21041185] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 01/25/2020] [Accepted: 02/01/2020] [Indexed: 12/15/2022] Open
Abstract
Breast cancer is the most commonly occurring cancer in women and the second most common cancer overall. By the age of 80, the estimated risk for breast cancer for women with germline BRCA1 or BRCA2 mutations is around 80%. Genetically engineered BRCA1-deficient mouse models offer a unique opportunity to study the pathogenesis and therapy of triple negative breast cancer. Here we present a newly established Brca1−/−, p53−/− mouse mammary tumor cell line, designated as CST. CST shows prominent features of BRCA1-mutated triple-negative breast cancers including increased motility, high proliferation rate, genome instability and sensitivity to platinum chemotherapy and PARP inhibitors (olaparib, veliparib, rucaparib and talazoparib). Genomic instability of CST cells was confirmed by whole genome sequencing, which also revealed the presence of COSMIC (Catalogue of Somatic Mutations in Cancer) mutation signatures 3 and 8 associated with homologous recombination (HR) deficiency. In vitro sensitivity of CST cells was tested against 11 chemotherapy agents. Tumors derived from orthotopically injected CST-mCherry cells in FVB-GFP mice showed sensitivity to cisplatin, providing a new model to study the cooperation of BRCA1-KO, mCherry-positive tumor cells and the GFP-expressing stromal compartment in therapy resistance and metastasis formation. In summary, we have established CST cells as a new model recapitulating major characteristics of BRCA1-negative breast cancers.
Collapse
Affiliation(s)
- Lilla Hámori
- Institute of Enzymology, Research Centre for Natural Sciences, 1117 Budapest, Hungary; (L.H.); (G.K.); (K.S.); (N.K.); (B.S.); (Á.P.); (G.V.); (D.S.)
| | - Gyöngyi Kudlik
- Institute of Enzymology, Research Centre for Natural Sciences, 1117 Budapest, Hungary; (L.H.); (G.K.); (K.S.); (N.K.); (B.S.); (Á.P.); (G.V.); (D.S.)
| | - Kornélia Szebényi
- Institute of Enzymology, Research Centre for Natural Sciences, 1117 Budapest, Hungary; (L.H.); (G.K.); (K.S.); (N.K.); (B.S.); (Á.P.); (G.V.); (D.S.)
- Institute of Cancer Research, Medical University of Vienna, 1090 Vienna, Austria
| | - Nóra Kucsma
- Institute of Enzymology, Research Centre for Natural Sciences, 1117 Budapest, Hungary; (L.H.); (G.K.); (K.S.); (N.K.); (B.S.); (Á.P.); (G.V.); (D.S.)
| | - Bálint Szeder
- Institute of Enzymology, Research Centre for Natural Sciences, 1117 Budapest, Hungary; (L.H.); (G.K.); (K.S.); (N.K.); (B.S.); (Á.P.); (G.V.); (D.S.)
| | - Ádám Póti
- Institute of Enzymology, Research Centre for Natural Sciences, 1117 Budapest, Hungary; (L.H.); (G.K.); (K.S.); (N.K.); (B.S.); (Á.P.); (G.V.); (D.S.)
| | - Ferenc Uher
- Central Hospital of Southern Pest—National Institute of Hematology and Infectious Diseases, 1097 Budapest, Hungary;
| | - György Várady
- Institute of Enzymology, Research Centre for Natural Sciences, 1117 Budapest, Hungary; (L.H.); (G.K.); (K.S.); (N.K.); (B.S.); (Á.P.); (G.V.); (D.S.)
| | - Dávid Szüts
- Institute of Enzymology, Research Centre for Natural Sciences, 1117 Budapest, Hungary; (L.H.); (G.K.); (K.S.); (N.K.); (B.S.); (Á.P.); (G.V.); (D.S.)
| | - József Tóvári
- Department of Experimental Pharmacology, National Institute of Oncology, 1122, Budapest, Hungary;
| | - András Füredi
- Institute of Enzymology, Research Centre for Natural Sciences, 1117 Budapest, Hungary; (L.H.); (G.K.); (K.S.); (N.K.); (B.S.); (Á.P.); (G.V.); (D.S.)
- Institute of Cancer Research, Medical University of Vienna, 1090 Vienna, Austria
- Correspondence: (A.F.); (G.S.)
| | - Gergely Szakács
- Institute of Enzymology, Research Centre for Natural Sciences, 1117 Budapest, Hungary; (L.H.); (G.K.); (K.S.); (N.K.); (B.S.); (Á.P.); (G.V.); (D.S.)
- Institute of Cancer Research, Medical University of Vienna, 1090 Vienna, Austria
- Correspondence: (A.F.); (G.S.)
| |
Collapse
|
4
|
Ahmad M, Jalil F, Haq M, Shah A. Effect of variation in miRNA-binding site (rs8176318) of the BRCA1 gene in breast cancer patients. Turk J Med Sci 2019; 49:1433-1438. [PMID: 31651107 PMCID: PMC7018252 DOI: 10.3906/sag-1905-17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Accepted: 07/17/2019] [Indexed: 12/24/2022] Open
Abstract
Background/aim A variation in the 3 prime untranslated regions (3′-UTRs) affects the binding of microRNA (miRNA) to the breast cancer (BC) susceptibility gene 1 (BRCA1) gene, and thus regulate its expression. In this study, the consequences of a variation in the miRNA-binding site (rs8176318G>T) in the 3′-UTRs of BRCA1 and its association with the risk of BC were investigated. Materials and methods The selected variation (rs8176318G>T) was genotyped in BC patients (n = 300) and healthy controls (n = 300) using allele-specific polymerase chain reaction (PCR) [tetra-primer amplification refractory mutation system-PCR (T-ARMS-PCR)]. The results of the T-ARMS-PCR were further confirmed by Sanger sequencing through a random selection of 10% previously analyzed samples by T-ARMS-PCR. Association of this variation with BC was tested by calculating the odds ratio (OR) (at 95% CI) and χ2-value using 4 different genetic models (codominant, dominant, recessive, and additive models). Results Using Fisher’s exact test, a significant association between variant rs8176318 (G>T) and BC was found in codominant [χ2-value = 15.68, df: 2 P < 0.0004], dominant [OR = 1.557 (1.082–2.241), P <0.0213], recessive [OR = 0.474 (0.3204–0.7017), P = 0.0002] and additive models [OR = 1.609 (1.282–2.018), P < 0.0001]. Conclusion It was therefore concluded that there is a significant association between rs8176318 and BC risk in a case-control study in a Pakistani population. Furthermore, an association study using a large sample size is required to further verify these findings.
Collapse
Affiliation(s)
- Mushtaq Ahmad
- Department of Biotechnology, Faculty of Biological Sciences University of Malakand, Chakdara, Pakistan
| | - Fazal Jalil
- Department of Biotechnology, Abdul Wali Khan University Mardan (AWKUM), Pakistan
| | - Mutiul Haq
- Institute of Radiotherapy and Nuclear Medicine (IRNUM), Peshawar, Pakistan
| | - Aftab Shah
- Department of Biotechnology, Faculty of Biological Sciences University of Malakand, Chakdara, Pakistan
| |
Collapse
|
5
|
Meng G. Applying Expression Profile Similarity for Discovery of Patient-Specific Functional Mutations. High Throughput 2018; 7:E6. [PMID: 29485617 PMCID: PMC5876532 DOI: 10.3390/ht7010006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Revised: 02/04/2018] [Accepted: 02/14/2018] [Indexed: 02/07/2023] Open
Abstract
The progress of cancer genome sequencing projects yields unprecedented information of mutations for numerous patients. However, the complexity of mutation profiles of cancer patients hinders the further understanding to mechanisms of oncogenesis. One basic question is how to find mutations with functional impacts. In this work, we introduce a computational method to predict functional somatic mutations of each patient by integrating mutation recurrence with expression profile similarity. With this method, the functional mutations are determined by checking the mutation enrichment among a group of patients with similar expression profiles. We applied this method to three cancer types and identified the functional mutations. Comparison of the predictions for three cancer types suggested that most of the functional mutations were cancer-type-specific with one exception to p53. By checking predicted results, we found that our method effectively filtered non-functional mutations resulting from large protein sizes. In addition, this method can also perform functional annotation to each patient to describe their association with signalling pathways or biological processes. In breast cancer, we predicted "cell adhesion" and other terms to be significantly associated with oncogenesis.
Collapse
Affiliation(s)
- Guofeng Meng
- BT science Inc., No. 24, Tang'an Road, Shanghai, China.
| |
Collapse
|
6
|
Xu GP, Zhao Q, Wang D, Xie WY, Zhang LJ, Zhou H, Chen SZ, Wu LF. The association between BRCA1 gene polymorphism and cancer risk: a meta-analysis. Oncotarget 2018; 9:8681-8694. [PMID: 29492227 PMCID: PMC5823592 DOI: 10.18632/oncotarget.24064] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Accepted: 11/17/2017] [Indexed: 12/20/2022] Open
Abstract
Many studies have reported that BRCA1 polymorphisms are associated with cancer risk, but the results remain controversial. The purpose of this meta-analysis is to evaluate the relationship between BRCA1 polymorphisms (rs799917, rs1799950, rs1799966, or rs16941) and cancer risk. Relevant studies were identified via a systematic search of the PubMed, Embase, and Web of Science databases up to July 31, 2017. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to examine the strength of the associations. Thirty-five studies published in 19 publications involving 28,094 cases and 50,657 controls were included in this meta-analysis. There was no obvious association between rs799917, rs1799966, or rs16941 polymorphisms and overall cancer risk in any genetic models. However, subgroup analyses revealed that the rs799917 polymorphism could decrease the risk of cervical cancer, esophageal squamous cell carcinoma (ESCC), gastric cancer, and non-Hodgkin lymphoma (NHL) among Asian populations in one or more genetic models and that rs16941 could increase overall cancer risk among Caucasian populations in the homozygote and recessive models. Our meta-analysis also indicated that rs1799950 could decrease the breast cancer (BC) risk among Caucasian populations in the homozygote and recessive models. In summary, our results suggest that BRCA1 polymorphisms may play an important role in the etiology of cancer. However, due to the limited number of studies, these findings should be confirmed by new studies with larger sample sizes that address various types of cancer.
Collapse
Affiliation(s)
- Gui-Ping Xu
- Transfusion Department, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Qing Zhao
- Department of Laboratory Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Ding Wang
- Department of Laboratory Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Wen-Yue Xie
- Department of Oncology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Li-Jun Zhang
- Department of Laboratory Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Hua Zhou
- Department of Laboratory Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Shi-Zhi Chen
- Department of Laboratory Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Li-Fang Wu
- Department of Laboratory Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| |
Collapse
|
7
|
Lei H, Deng CX. Fibroblast Growth Factor Receptor 2 Signaling in Breast Cancer. Int J Biol Sci 2017; 13:1163-1171. [PMID: 29104507 PMCID: PMC5666331 DOI: 10.7150/ijbs.20792] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 05/18/2017] [Indexed: 01/03/2023] Open
Abstract
Fibroblast growth factor receptor 2 (FGFR2) is a membrane-spanning tyrosine kinase that mediates signaling for FGFs. Recent studies detected various point mutations of FGFR2 in multiple types of cancers, including breast cancer, lung cancer, gastric cancer, uterine cancer and ovarian cancer, yet the casual relationship between these mutations and tumorigenesis is unclear. Here we will discuss possible interactions between FGFR2 signaling and several major pathways through which the aberrantly activated FGFR2 signaling may result in breast cancer development. We will also discuss some recent developments in the discovery and application of therapies and strategies for breast cancers by inhibiting FGFR2 activities.
Collapse
Affiliation(s)
- Haipeng Lei
- Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Chu-Xia Deng
- Faculty of Health Sciences, University of Macau, Macau SAR, China
| |
Collapse
|
8
|
Wang X, El-Halaby AA, Zhang H, Yang Q, Laughlin TS, Rothberg PG, Skinner K, Hicks DG. p53 alteration in morphologically normal/benign breast luminal cells in BRCA carriers with or without history of breast cancer. Hum Pathol 2017; 68:22-25. [PMID: 28438622 DOI: 10.1016/j.humpath.2017.04.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 03/25/2017] [Accepted: 04/07/2017] [Indexed: 11/29/2022]
Abstract
Germline mutations in BRCA genes have been shown to predispose patients to breast cancer. Studies have suggested that p53 alteration is a necessary step in tumorigenesis in BRCA carriers. Our previous study showed p53 alteration in morphologically normal/benign breast luminal cells in sporadic breast cancer patients, the so-called breast p53 signature. Here, we studied p53 status in 66 BRCA1/2 carriers' breasts: 29 patients with breast carcinoma (2 patients with bilateral breast carcinomas) and 37 without. Seven of the 12 (58%) triple-negative breast carcinomas in BRCA carriers were positive for p53 alteration (immunohistochemical stain and/or sequencing), the same frequency as in sporadic triple-negative breast carcinomas. Focal p53 positivity in adjacent normal/benign luminal cells was identified in 4 of the 7 cases with p53-positive carcinomas but not in breasts with p53-negative carcinomas, indicating that p53 positivity in normal/benign breast luminal cells is not a random event. Furthermore, in BRCA carriers' prophylactic mastectomies, 12 of the 94 (12.77%) breasts had focal p53 positivity in normal/benign luminal cells, with 2 cases in bilateral breasts, significantly higher than in previously studied mammoplasty specimens (0%). Our study suggests that germline BRCA gene mutations could result in genomic instability and an elevated gene mutation rate (such as the p53 gene) in breast luminal cells compared with the general population, predisposing BRCA carriers to develop p53-positive/triple-negative breast carcinomas.
Collapse
Affiliation(s)
- Xi Wang
- Department of Pathology, University of Rochester Medical Center, Rochester, NY 14642.
| | - Amber A El-Halaby
- Department of Pathology, University of Rochester Medical Center, Rochester, NY 14642
| | - Hengwei Zhang
- Department of Pathology, University of Rochester Medical Center, Rochester, NY 14642
| | - Qi Yang
- Department of Pathology, University of Rochester Medical Center, Rochester, NY 14642
| | - Todd S Laughlin
- Department of Pathology, University of Rochester Medical Center, Rochester, NY 14642
| | - Paul G Rothberg
- Department of Pathology, University of Rochester Medical Center, Rochester, NY 14642
| | - Kristin Skinner
- Department of Surgery, University of Rochester Medical Center, Rochester, NY 14642
| | - David G Hicks
- Department of Pathology, University of Rochester Medical Center, Rochester, NY 14642
| |
Collapse
|
9
|
Li M, Cole F, Patel DS, Misenko SM, Her J, Malhowski A, Alhamza A, Zheng H, Baer R, Ludwig T, Jasin M, Nussenzweig A, Serrano L, Bunting SF. 53BP1 ablation rescues genomic instability in mice expressing 'RING-less' BRCA1. EMBO Rep 2016; 17:1532-1541. [PMID: 27670884 DOI: 10.15252/embr.201642497] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 09/09/2016] [Indexed: 11/09/2022] Open
Abstract
BRCA1 mutations strongly predispose affected individuals to breast and ovarian cancer, but the mechanism by which BRCA1 acts as a tumor suppressor is not fully understood. Homozygous deletion of exon 2 of the mouse Brca1 gene normally causes embryonic lethality, but we show that exon 2-deleted alleles of Brca1 are expressed as a mutant isoform that lacks the N-terminal RING domain. This "RING-less" BRCA1 protein is stable and efficiently recruited to the sites of DNA damage. Surprisingly, robust RAD51 foci form in cells expressing RING-less BRCA1 in response to DNA damage, but the cells nonetheless display the substantial genomic instability. Genomic instability can be rescued by the deletion of Trp53bp1, which encodes the DNA damage response factor 53BP1, and mice expressing RING-less BRCA1 do not show an increased susceptibility to tumors in the absence of 53BP1. Genomic instability in cells expressing RING-less BRCA1 correlates with the loss of BARD1 and a defect in restart of replication forks after hydroxyurea treatment, suggesting a role of BRCA1-BARD1 in genomic integrity that is independent of RAD51 loading.
Collapse
Affiliation(s)
- Minxing Li
- Department of Molecular Biology and Biochemistry, Rutgers The State University of New Jersey, Piscataway, NJ, USA
| | - Francesca Cole
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.,Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX, USA
| | - Dharm S Patel
- Department of Molecular Biology and Biochemistry, Rutgers The State University of New Jersey, Piscataway, NJ, USA
| | - Sarah M Misenko
- Department of Molecular Biology and Biochemistry, Rutgers The State University of New Jersey, Piscataway, NJ, USA
| | - Joonyoung Her
- Department of Molecular Biology and Biochemistry, Rutgers The State University of New Jersey, Piscataway, NJ, USA
| | - Amy Malhowski
- Laboratory of Genome Integrity, Center for Cancer Research, National Cancer Institute National Institutes of Health, Bethesda, MD, USA
| | - Ali Alhamza
- Department of Molecular Biology and Biochemistry, Rutgers The State University of New Jersey, Piscataway, NJ, USA
| | - Haiyan Zheng
- Biological Mass Spectrometry Facility, Rutgers The State University of New Jersey, Piscataway, NJ, USA
| | - Richard Baer
- Institute of Cancer Genetics, Department of Pathology & Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Thomas Ludwig
- Department of Cancer Biology & Genetics, Ohio State University, Columbus, OH, USA
| | - Maria Jasin
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - André Nussenzweig
- Laboratory of Genome Integrity, Center for Cancer Research, National Cancer Institute National Institutes of Health, Bethesda, MD, USA
| | - Lourdes Serrano
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers The State University of New Jersey, Piscataway, NJ, USA
| | - Samuel F Bunting
- Department of Molecular Biology and Biochemistry, Rutgers The State University of New Jersey, Piscataway, NJ, USA
| |
Collapse
|
10
|
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.
Collapse
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
| |
Collapse
|
11
|
The proteasome factor Bag101 binds to Rad22 and suppresses homologous recombination. Sci Rep 2014; 3:2022. [PMID: 23779158 PMCID: PMC3685826 DOI: 10.1038/srep02022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 05/31/2013] [Indexed: 11/08/2022] Open
Abstract
Although RAD52 plays a critical role in the initiation of homologous recombination (HR) by facilitating the replacement of RPA with RAD51, the mechanism controlling RAD52 remains elusive. Here, we show that Bag101, a factor implicated in proteasome functioning, regulates RAD52 protein levels and subsequent HR. LC-MS/MS analysis identified Bag101 which binds to Rad22, the fission yeast homologue of RAD52. Bag101 reduced HR frequency through its overexpression and conversely, HR frequencies were enhanced when it was deleted. Consistent with this observation, Rad22 protein levels was reduced in cells where bag101 was overexpressed even when Rad22 transcription was up-regulated, suggesting the operation of proteasome-mediated Rad22 degradation. Indeed, Rad22 protein levels were stabilized in proteasome mutants. Rad22 physically interacted with the BAG domain of Bag101, and a lack of this domain enhanced HR frequency. Similarly, radiation exposure triggered the dissociation of these proteins so that Rad22 was stabilized and able to enhance HR.
Collapse
|
12
|
Yi YW, Kang HJ, Bae I. BRCA1 and Oxidative Stress. Cancers (Basel) 2014; 6:771-95. [PMID: 24704793 PMCID: PMC4074803 DOI: 10.3390/cancers6020771] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 03/20/2014] [Accepted: 03/24/2014] [Indexed: 01/07/2023] Open
Abstract
The breast cancer susceptibility gene 1 (BRCA1) has been well established as a tumor suppressor and functions primarily by maintaining genome integrity. Genome stability is compromised when cells are exposed to oxidative stress. Increasing evidence suggests that BRCA1 regulates oxidative stress and this may be another mechanism in preventing carcinogenesis in normal cells. Oxidative stress caused by reactive oxygen species (ROS) is implicated in carcinogenesis and is used strategically to treat human cancer. Thus, it is essential to understand the function of BRCA1 in oxidative stress regulation. In this review, we briefly summarize BRCA1's many binding partners and mechanisms, and discuss data supporting the function of BRCA1 in oxidative stress regulation. Finally, we consider its significance in prevention and/or treatment of BRCA1-related cancers.
Collapse
Affiliation(s)
- Yong Weon Yi
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA.
| | - Hyo Jin Kang
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA.
| | - Insoo Bae
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA.
| |
Collapse
|
13
|
Shabbeer S, Omer D, Berneman D, Weitzman O, Alpaugh A, Pietraszkiewicz A, Metsuyanim S, Shainskaya A, Papa MZ, Yarden RI. BRCA1 targets G2/M cell cycle proteins for ubiquitination and proteasomal degradation. Oncogene 2012; 32:5005-16. [PMID: 23246971 DOI: 10.1038/onc.2012.522] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 09/25/2012] [Accepted: 10/04/2012] [Indexed: 12/27/2022]
Abstract
The BRCA1 tumor suppressor protein heterodimerizes with its partner protein, BARD1, via the RING domain present in both proteins. The heterodimer contains an E3 ubiquitin ligase activity and participates in multiple cellular functions such as cell cycle control, DNA repair and regulation of gene transcription, collectively aimed at maintaining genomic stability and tumor suppression. Yet, the precise role of BRCA1 E3 ligase in these cellular functions is poorly understood. We present data showing that BRCA1 ubiquitinates G2/M cell cycle proteins, cyclin B and Cdc25C, leading to their accelerated degradation via a mechanism that is independent of APC/C. BRCA1-dependent degradation of cyclin B and Cdc25C is reversed by proteasome inhibitors and is enhanced following DNA damage, which may represent a possible mechanism to prevent cyclin B and Cdc25C accumulation, a requirement for mitotic entry. Our data provide mechanistic insight into how BRCA1 E3 ligase activity regulates the G2/M cell cycle checkpoint and, thus, contributes to maintenance of genomic stability.
Collapse
Affiliation(s)
- S Shabbeer
- 1] Department of Human Science, SNHS, Georgetown University Medical Center, Washington, DC, USA [2] Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Sekine M, Yoshihara K, Komata D, Haino K, Nishino K, Tanaka K. Increased incidence of brain metastases in BRCA1-related ovarian cancers. J Obstet Gynaecol Res 2012; 39:292-6. [PMID: 22889437 DOI: 10.1111/j.1447-0756.2012.01961.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM Brain metastasis from ovarian cancer is a very rare phenomenon. BRCA1-related ovarian cancers show specific pathobiological profiles, advanced stage, and sensitivity to chemotherapeutic agents. However, no clear relationship to any known metastatic behavior has yet been found, so we examined the BRCA1 mutation and expression profiles in ovarian cancer cases with brain metastases. MATERIAL AND METHODS We examined our clinical records of 340 ovarian cancer cases from 1983 to 2007 to ascertain cases with brain metastases. In the molecular genetic analyses, we performed loss of heterozygosity (LOH), direct sequence and immunohistochemical staining analysis of BRCA1. RESULTS We ascertained seven cases with brain metastases in 340 ovarian cancer cases (7/340=2.1%). Among the seven cases, three cases had ovarian and/or breast cancer patients in third-degree relatives. We detected four LOH-positive cases and a germline mutation of BRCA1 in two of the four cases. Furthermore, the remaining two cases showed absent staining of the BRCA1 protein. Therefore, four of seven cases with brain metastases were considered BRCA1-related ovarian cancers (4/7=57.1%). All four of the cases were serous adenocarcinoma. CONCLUSION Our results suggest that the loss of BRCA1 function may be involved in the phenomenon of brain metastasis from ovarian cancer. Further molecular biologic analyses will be required for a better understanding of this rare phenomenon.
Collapse
Affiliation(s)
- Masayuki Sekine
- Department of Obstetrics and Gynecology, Niigata University Graduate School of Medical and Dental Science, Niigata, Japan
| | | | | | | | | | | |
Collapse
|
15
|
Wagh PK, Zinser GM, Gray JK, Shrestha A, Waltz SE. Conditional deletion of β-catenin in mammary epithelial cells of Ron receptor, Mst1r, overexpressing mice alters mammary tumorigenesis. Endocrinology 2012; 153:2735-46. [PMID: 22474186 PMCID: PMC3359604 DOI: 10.1210/en.2011-1543] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The Ron receptor tyrosine kinase (macrophage stimulating 1 receptor) is overexpressed in approximately 50% of human breast cancers. Transgenic mice overexpressing Ron in the mammary epithelium [mouse mammary tumor virus driven (MMTV)-Ron expressing mice] develop mammary tumors that exhibit up-regulation of β-catenin and β-catenin target genes. β-Catenin has been shown to be a mediator of mammary tumorigenesis in various breast cancer models, including downstream of Ron. However, the in vivo impact of a conditional loss of β-catenin downstream of Ron receptor overexpression on the onset, growth, turnover, and metastasis of mammary tumors has not been addressed. To determine the significance of β-catenin in the context of Ron overexpression, we conditionally deleted β-catenin in mammary epithelial cells of MMTV-Ron mice. Conditional deletion of β-catenin in the mammary epithelium, through the use of whey acidic protein (WAP)-Cre transgenic mice, significantly delayed the onset of mammary hyperplastic nodules, the presence of palpable mammary tumors, and ultimately decreased liver metastasis. β-Catenin loss in this model was also associated with decreased expression of cyclin D1. In total, these studies support an important role for β-catenin downstream of Ron receptor signaling during the development of mammary tumorigenesis.
Collapse
MESH Headings
- Animals
- Blotting, Western
- Cell Transformation, Neoplastic/genetics
- Cyclin D1/genetics
- Cyclin D1/metabolism
- Epithelial Cells/metabolism
- Female
- Gene Expression Regulation, Neoplastic
- Hyperplasia
- Liver Neoplasms/genetics
- Liver Neoplasms/metabolism
- Liver Neoplasms/secondary
- Male
- Mammary Glands, Animal/metabolism
- Mammary Glands, Animal/pathology
- Mammary Neoplasms, Experimental/genetics
- Mammary Neoplasms, Experimental/metabolism
- Mammary Neoplasms, Experimental/pathology
- Mice
- Mice, Knockout
- Mice, Transgenic
- Receptor Protein-Tyrosine Kinases/genetics
- Receptor Protein-Tyrosine Kinases/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Time Factors
- beta Catenin/deficiency
- beta Catenin/genetics
Collapse
Affiliation(s)
- Purnima K Wagh
- Department of Cancer and Cell Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0521, USA
| | | | | | | | | |
Collapse
|
16
|
Xiang T, Jia Y, Sherris D, Li S, Wang H, Lu D, Yang Q. Targeting the Akt/mTOR pathway in Brca1-deficient cancers. Oncogene 2011; 30:2443-50. [PMID: 21242970 PMCID: PMC3107712 DOI: 10.1038/onc.2010.603] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 11/23/2010] [Accepted: 11/23/2010] [Indexed: 02/07/2023]
Abstract
The breast cancer susceptibility gene 1 (Brca1) has a key role in both hereditary and sporadic mammary tumorigenesis. However, the reasons why Brca1-deficiency leads to the development of cancer are not clearly understood. Activation of Akt kinase is one of the most common molecular alterations associated with human malignancy. Increased Akt kinase activity has been reported in most breast cancers. We previously found that downregulation of Brca1 expression or mutations of the Brca1 gene activate the Akt oncogenic pathway. To further investigate the role of Brca1/Akt in tumorigenesis, we analyzed Brca1/Akt expression in human breast cancer samples and found that reduced expression of Brca1 was highly correlated with increased phosphorylation of Akt. Consistent with the clinical data, knockdown of Akt1 by short-hairpin RNA inhibited cellular proliferation of Brca1 mutant cells. Importantly, depletion of Akt1 significantly reduced tumor formation induced by Brca1-deficiency in mice. The third generation inhibitor of mammalian target of rapamycin (mTOR), Palomid 529, significantly suppressed Brca1-deficient tumor growth in mice through inhibition of both Akt and mTOR signaling. Our results indicate that activation of Akt is involved in Brca1-deficiency mediated tumorigenesis and that the mTOR pathway can be used as a novel target for treatment of Brca1-deficient cancers.
Collapse
MESH Headings
- Animals
- BRCA1 Protein/deficiency
- BRCA1 Protein/genetics
- Benzopyrans/pharmacology
- Blotting, Western
- Breast Neoplasms/genetics
- Breast Neoplasms/metabolism
- Breast Neoplasms/pathology
- Cell Line, Tumor
- Cells, Cultured
- Embryo, Mammalian/cytology
- Female
- Fibroblasts/metabolism
- Humans
- Immunohistochemistry
- Mammary Neoplasms, Experimental/drug therapy
- Mammary Neoplasms, Experimental/genetics
- Mammary Neoplasms, Experimental/pathology
- Mice
- Mice, Inbred NOD
- Mice, Knockout
- Mice, SCID
- Middle Aged
- Mutation
- Proto-Oncogene Proteins c-akt/genetics
- Proto-Oncogene Proteins c-akt/metabolism
- RNA Interference
- Signal Transduction
- TOR Serine-Threonine Kinases/genetics
- TOR Serine-Threonine Kinases/metabolism
- Tumor Burden/drug effects
- Xenograft Model Antitumor Assays
Collapse
Affiliation(s)
- T Xiang
- Department of Radiation Oncology, Washington University School of Medicine, St Louis, MO, USA
| | - Y Jia
- Department of Radiation Oncology, Washington University School of Medicine, St Louis, MO, USA
| | - D Sherris
- Paloma Pharmaceuticals, Jamaica Plain, MA, USA
| | - S Li
- Department of Medicine and Siteman Cancer Center, Washington University School of Medicine, St Louis, MO, USA
| | - H Wang
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, St Louis, MO, USA
| | - D Lu
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, USA
| | - Q Yang
- Department of Radiation Oncology, Washington University School of Medicine, St Louis, MO, USA
| |
Collapse
|
17
|
Kim KY, Park DW, Jeung EB, Choi KC. Conditional knockout of brca1/2 and p53 in mouse ovarian surface epithelium: do they play a role in ovarian carcinogenesis? J Vet Sci 2011; 11:291-7. [PMID: 21113097 PMCID: PMC2998739 DOI: 10.4142/jvs.2010.11.4.291] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Alterations of genes are known to be critical for the induction of tumorigenesis, but the mechanism of ovarian carcinogenesis is little understood and remains to be elucidated. In this study, we investigated the roles of brca1, brca2 and p53 genes in the development of ovarian cancer using conditional knockout mice generated by a Cre-loxP recombinant system. Following the application of recombinant adenovirus expressing Cre in vitro, the proliferation of ovarian surface epithelium (OSE) was increased. For instance, a significant increase in cell growth was observed in OSE cells in vitro by conditional knockout isolated from the mice bearing concurrent floxed copies of brca1 and brca2/p53. However, the proliferative effect of the ovarian cells was not observed in concurrent brca1/brca2 or p53 knockout mice in vivo, indicating that we could not observe the direct evidence of the involvement of brca1, brca2, and p53 in ovarian carcinogenesis. Since morphological changes including tumor formation were not observed in mice bearing floxed copies of concurrent brca1/brca2 or p53, the inactivation of brca1/2 or p53 is not sufficient for the induction of tumor formation. Taken together, these results suggest that the deficiency of these genes may not be involved directly in the mechanism of ovarian carcinogenesis.
Collapse
Affiliation(s)
- Ki-Yon Kim
- Department of Obstetrics and Gynecology, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | | | | | | |
Collapse
|
18
|
Norquist BM, Garcia RL, Allison KH, Jokinen CH, Kernochan LE, Pizzi CC, Barrow BJ, Goff BA, Swisher EM. The molecular pathogenesis of hereditary ovarian carcinoma: alterations in the tubal epithelium of women with BRCA1 and BRCA2 mutations. Cancer 2011; 116:5261-71. [PMID: 20665887 DOI: 10.1002/cncr.25439] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND BRCA1 or BRCA2 (BRCA1/2)-mutated ovarian carcinomas may originate in the fallopian tube. The authors of this report investigated alterations in BRCA1/2 tubal epithelium to define the molecular pathogenesis of these carcinomas. METHODS Tubal epithelium was evaluated from 31 BRCA1/2 mutation carriers with gynecologic carcinomas (BRCA CA), 89 mutation carriers who underwent risk-reducing salpingo-oophorectomy (RRSO), and 87 controls. Ki-67 expression and p53 foci (≥10 of 12 consecutive staining cells) were scored by 2 investigators who were blinded to patient designations. Expression levels of p27 and p21 were evaluated within p53 foci. Loss of heterozygosity at the BRCA1/2 mutation site was evaluated in microdissected p53 foci and tubal neoplasms. RESULTS Background tubal proliferation as measured by Ki-67 staining was increased in the BRCA1 RRSO group (P = .005) compared with the control group. Women who had BRCA1/2 mutations had more p53 foci identified per tubal segment than women in the control group (P = .02). Levels of p27 were decreased in 12 of 28 p53 foci from women with BRCA1 mutations and in 0 of 16 p53 foci from controls (P = .002). There was no loss of the wild type BRCA1/2 allele in 5 tested p53 foci. Tubal neoplasia lost the wild type allele in 6 of 6 foci (P = .002). CONCLUSIONS The current results suggested a model of tubal carcinogenesis in women with BRCA1/2 mutations. Increased proliferation occurred globally in at-risk tubal epithelium. A mutation in the tumor protein p53 gene TP53 with clonal proliferation and loss of p27 occurred before neoplastic proliferation. Loss of the wild type BRCA1/2 allele occurred with neoplastic proliferation and before invasion.
Collapse
Affiliation(s)
- Barbara M Norquist
- Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle, WA, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Abstract
Hereditary breast and ovarian cancer due to mutations in the BRCA1 and BRCA2 genes is the most common cause of hereditary forms of both breast and ovarian cancer. The overall prevalence of BRCA1/2 mutations is estimated to be from 1 in 400 to 1 in 800 with a higher prevalence in the Ashkenazi Jewish population (1 in 40). Estimates of penetrance (cancer risk) vary considerably depending on the context in which they were derived and have been shown to vary within families with the same BRCA1/2 mutation. This suggests there is no exact risk estimate that can be applied to all individuals with a BRCA1/2 mutation. The likelihood of harboring a BRCA1 or BRCA2 mutation is dependent on one's personal and/or family history of cancer and can be estimated using various mutation probability models. For those individuals who have a BRCA1 or BRCA2 mutation, several screening and primary prevention options have been suggested, including prophylactic surgery and chemoprevention. Once a BRCA1 or BRCA2 mutation has been identified in a family, testing of at-risk relatives can identify those family members who also have the familial mutation and thus need increased surveillance and early intervention when a cancer is diagnosed.
Collapse
|
20
|
Gene Mutations in Animal Models: Do Tumor Suppressor Genes, brca1 and brca2, Play a Role in Ovarian Carcinogenesis? Lab Anim Res 2010. [DOI: 10.5625/lar.2010.26.4.323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
|
21
|
Lee EJ, Oh SY, Kim MK, Ahn SH, Son BH, Sung MK. Modulatory effects of alpha- and gamma-tocopherols on 4-hydroxyestradiol induced oxidative stresses in MCF-10A breast epithelial cells. Nutr Res Pract 2009; 3:185-91. [PMID: 20090883 PMCID: PMC2808717 DOI: 10.4162/nrp.2009.3.3.185] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Revised: 09/10/2009] [Accepted: 09/16/2009] [Indexed: 11/17/2022] Open
Abstract
The elevated level of circulating estradiol increases the risk of breast tumor development. To gain further insight into mechanisms involved in their actions, we investigated the molecular mechanisms of 4-hydroxyestradiol (4-OHE2) to initiate and/or promote abnormal cell growth, and of α- or γ-tocopherol to inhibit this process. MCF-10A, human breast epithelial cells were incubated with 0.1 µM 4-OHE2, either with or without 30 µM tocopherols for 96 h. 4-OHE2 caused the accumulation of intracellular ROS, while cellular GSH/GSSG ratio and MnSOD protein levels were decreased, indicating that there was an oxidative burden. 4-OHE2 treatment also changed the levels of DNA repair proteins, BRCA1 and PARP-1. γ-Tocopherol suppressed the 4-OHE2-induced increases in ROS, GSH/GSSG ratio, and MnSOD protein expression, while α-tocopherol up-regulated BRCA1 and PARP-1 protein expression. In conclusion, 4-OHE2 increases oxidative stress reducing the level of proteins related to DNA repair. Tocopherols suppressed oxidative stress by scavenging ROS or up-regulating DNA repair elements.
Collapse
Affiliation(s)
- Eun-Ju Lee
- Department of Food and Nutrition, Sookmyung Women's University, 52 Hyochangwon-gil, Yongsan-gu, Seoul 140-742, Korea
| | | | | | | | | | | |
Collapse
|
22
|
Mammary tumors initiated by constitutive Cdk2 activation contain an invasive basal-like component. Neoplasia 2008; 10:1240-52. [PMID: 18953433 DOI: 10.1593/neo.08710] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2008] [Revised: 08/13/2008] [Accepted: 08/14/2008] [Indexed: 12/31/2022] Open
Abstract
The basal-like subtype of breast cancer is associated with invasiveness, high rates of postsurgical recurrence, and poor prognosis. Aside from inactivation of the BRCA1 tumor-suppressor gene, little is known concerning the mechanisms that cause basal breast cancer or the mechanisms responsible for its invasiveness. Here, we show that the heterogeneous mouse mammary tumor virus-cyclin D1-Cdk2 (MMTV-D1K2) transgenic mouse mammary tumors contain regions of spindle-shaped cells expressing both luminal and myoepithelial markers. Cell lines cultured from these tumors exhibit the same luminal/myoepithelial mixed-lineage phenotype that is associated with human basal-like breast cancer and express a number of myoepithelial markers including cytokeratin 14, P-cadherin, alpha smooth muscle actin, and nestin. The MMTV-D1K2 tumor-derived cell lines form highly invasive tumors when injected into mouse mammary glands. Invasion is associated with E-cadherin localization to the cytoplasm or loss of E-cadherin expression. Cytoplasmic E-cadherin correlates with lack of colony formation in vitro and beta-catenin and p120(ctn) localization to the cytoplasm. The data suggest that the invasiveness of these cell lines results from a combination of factors including mislocalization of E-cadherin, beta-catenin, and p120(ctn) to the cytoplasm. Nestin expression and E-cadherin mislocalization were also observed in human basal-like breast cancer cell lines, suggesting that these results are relevant to human tumors. Together, these results suggest that abnormal Cdk2 activation may contribute to the formation of basal-like breast cancers.
Collapse
|
23
|
Xiong B, Li S, Ai JS, Yin S, Ouyang YC, Sun SC, Chen DY, Sun QY. BRCA1 is required for meiotic spindle assembly and spindle assembly checkpoint activation in mouse oocytes. Biol Reprod 2008; 79:718-26. [PMID: 18596218 DOI: 10.1095/biolreprod.108.069641] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
BRCA1 as a tumor suppressor has been widely investigated in mitosis, but its functions in meiosis are unclear. In the present study, we examined the expression, localization, and function of BRCA1 during mouse oocyte meiotic maturation. We found that expression level of BRCA1 was increased progressively from germinal vesicle to metaphase I stage, and then remained stable until metaphase II stage. Immunofluorescent analysis showed that BRCA1 was localized to the spindle poles at metaphase I and metaphase II stages, colocalizing with centrosomal protein gamma-tubulin. Taxol treatment resulted in the presence of BRCA1 onto the spindle microtubule fibers, whereas nocodazole treatment induced the localization of BRCA1 onto the chromosomes. Depletion of BRCA1 by both antibody injection and siRNA injection caused severely impaired spindles and misaligned chromosomes. Furthermore, BRCA1-depleted oocytes could not arrest at the metaphase I in the presence of low-dose nocodazole, suggesting that the spindle checkpoint is defective. Also, in BRCA1-depleted oocytes, gamma-tubulin dissociated from spindle poles and MAD2L1 failed to rebind to the kinetochores when exposed to nocodazole at metaphase I stage. Collectively, these data indicate that BRCA1 regulates not only meiotic spindle assembly, but also spindle assembly checkpoint, implying a link between BRCA1 deficiency and aneuploid embryos.
Collapse
Affiliation(s)
- Bo Xiong
- State Key Laboratory of Reproductive Biology, Chinese Academy of Sciences, 100080 Beijing, China
| | | | | | | | | | | | | | | |
Collapse
|
24
|
The BARD1 Cys557Ser polymorphism and breast cancer risk: an Australian case-control and family analysis. Breast Cancer Res Treat 2008; 115:145-50. [PMID: 18481171 DOI: 10.1007/s10549-008-0045-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2008] [Accepted: 04/28/2008] [Indexed: 01/13/2023]
Abstract
BARD1 was first identified as a BRCA1-interacting protein with tumour-suppressor functions. Some association studies suggested that the BARD1 Cys557Ser variant might be associated with increased risk of breast cancer, but the evidence remains uncertain. We found that the BARD1 Cys557Ser variant was carried by 50 of 1,136 cases (4.4%) and 30 of 623 controls (5.0%) from the population-based Australian Breast Cancer Family Study, 14 of 324 (4.3%) cases from the Kathleen Cuningham Foundation Consortium for Research into Familial Breast Cancer (kConFab), and 30 of 760 controls (4.0%) from the Australian Ovarian Cancer Study. Case-control comparisons showed no evidence that the variant frequency differed by case-control status (P >or= 0.3). Segregation analysis of 14 kConFab variant-carrying families containing 157 genotyped individuals provided no evidence of segregation with disease. We conclude that the BARD1 Cys557Ser variant is not associated with breast cancer risk.
Collapse
|
25
|
Raman V, Pathak AP, Glunde K, Artemov D, Bhujwalla ZM. Magnetic resonance imaging and spectroscopy of transgenic models of cancer. NMR IN BIOMEDICINE 2007; 20:186-99. [PMID: 17451171 DOI: 10.1002/nbm.1136] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The complexity of cancer, where a single genetic alteration can have multiple functional effects, makes it a fascinating but humbling disease to study, and the necessity of investigating it in its entirety is more imperative than ever before. Advances in transgene technology have made it possible to create cancer cells, or mice with specific genetic alterations, and the application of an array of both functional and molecular non-invasive MR methods to these transgenic cancer cells and mice to characterize their phenotypic traits is revolutionizing our understanding of cancer. With the establishment of multi-modality molecular imaging centers within barrier or pathogen-free facilities, multi-parametric and multi-modality imaging of transgenic mouse models of human cancer are becoming increasingly prevalent. In this review, we outline some of the methods currently available for generating transgenic mice and cancer cell lines. We also present examples of the application of MR methods to transgenic models that are providing novel insights into the molecular and functional characteristics of cancer and are leading to an era of "non-invasive phenotyping" of the effects of specific molecular alterations in cancer.
Collapse
Affiliation(s)
- Venu Raman
- JHU ICMIC Program, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | | | | | | | | |
Collapse
|
26
|
McCarthy A, Savage K, Gabriel A, Naceur C, Reis-Filho JS, Ashworth A. A mouse model of basal-like breast carcinoma with metaplastic elements. J Pathol 2007; 211:389-98. [PMID: 17212342 DOI: 10.1002/path.2124] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Breast cancers arising in carriers of germline BRCA1 mutations frequently have a basal-like phenotype. Basal-like cancers are characterized by high histological grade, central necrotic areas, foci with metaplastic differentiation, lack of hormone receptor and HER2 (ErbB2) expression, and consistent positivity for basal markers, including CK5/6, CK14, and EGFR. We have used germline manipulation to generate a conditional mouse model of Brca1 deficiency. Transgenic expression of Cre recombinase in the mammary gland of these mice results in deletion of exons encoding the C-terminus of Brca1 and leads to tumour formation when combined with heterozygosity for a p53 mutation. Histologically, these mammary gland tumours were characterized by high histological grade, central necrotic areas, and presence of homologous metaplastic elements. These metaplastic elements consisted of neoplastic spindle cells or squamous cell differentiation in the form of keratin pearls or individual cell keratinization. Immunohistochemical analysis revealed expression of basal-like markers in all cases. The tumour phenotype generated in our mouse model was compared with published data on human basal-like breast carcinomas and also with metaplastic breast cancers with a basal-like phenotype; the comparison showed that we have generated a mouse model of basal-like breast cancer, which should prove useful in testing new and targeted treatments for this type of breast cancer.
Collapse
Affiliation(s)
- A McCarthy
- The Breakthrough Breast Cancer Research Centre, Institute of Cancer Research, London SW3 6JB, UK
| | | | | | | | | | | |
Collapse
|
27
|
Silver DP, Dimitrov SD, Feunteun J, Gelman R, Drapkin R, Lu SD, Shestakova E, Velmurugan S, Denunzio N, Dragomir S, Mar J, Liu X, Rottenberg S, Jonkers J, Ganesan S, Livingston DM. Further evidence for BRCA1 communication with the inactive X chromosome. Cell 2007; 128:991-1002. [PMID: 17350581 DOI: 10.1016/j.cell.2007.02.025] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Revised: 10/30/2006] [Accepted: 02/21/2007] [Indexed: 10/23/2022]
Abstract
BRCA1, a breast and ovarian cancer-suppressor gene, exerts tumor-suppressing functions that appear to be associated, at least in part, with its DNA repair, checkpoint, and mitotic regulatory activities. Earlier work from our laboratory also suggested an ability of BRCA1 to communicate with the inactive X chromosome (Xi) in female somatic cells (Ganesan et al., 2002). Xiao et al. (2007) (this issue of Cell) have challenged this conclusion. Here we discuss recently published data from our laboratory and others and present new results that, together, provide further support for a role of BRCA1 in the regulation of XIST concentration on Xi in somatic cells.
Collapse
Affiliation(s)
- Daniel P Silver
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Choi DH, Lee MH, Haffty BG. Double heterozygotes for non-Caucasian families with mutations in BRCA-1 and BRCA-2 genes. Breast J 2006; 12:216-20. [PMID: 16684319 DOI: 10.1111/j.1075-122x.2006.00245.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The recent discovery of the BRCA-1 and BRCA-2 genes as contributing factors to hereditary breast cancer has significantly improved our understanding of familial breast cancer. Deleterious mutations in both BRCA-1 and BRCA-2 in an individual patient is exceedingly rare, with few case reports in the literature, particularly among non-Caucasian, non-Jewish families. We describe here two cases of deleterious mutations in both genes in a cohort of Korean women with early onset breast cancer.
Collapse
Affiliation(s)
- Doo Ho Choi
- Department of Radiation Oncology and Surgery, College of Medicine, Soonchungyang University, Seoul, Korea
| | | | | |
Collapse
|
29
|
De Soto JA, Deng CX. PARP-1 inhibitors: are they the long-sought genetically specific drugs for BRCA1/2-associated breast cancers? Int J Med Sci 2006; 3:117-23. [PMID: 16906222 PMCID: PMC1525219 DOI: 10.7150/ijms.3.117] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2006] [Accepted: 07/12/2006] [Indexed: 01/15/2023] Open
Abstract
Recent studies demonstrated that PARP-1 [poly(ADP-ribose) polymerase-1] inhibitors kill breast cancer associated gene-1 and -2 (BRCA1/2) deficient cells with extremely high efficiency while BRCA+/- and BRCA+/+ cells are relatively non-responsive to the treatment. It was therefore proposed that PARP-1 inhibitors might be the long-sought genetically specific drugs that are both safe and effective for treating BRCA1/2-associated breast cancers. However, a report published in a recent issue of the International Journal of Biological Sciences revealed that PARP-1 inhibitors, although able to kill naïve BRCA1 mutant cells with high specificity both in vitro and in vivo, exhibit minimal specificity in inhibiting the growth of mouse mammary tumor cells irrespective of their BRCA1 status in allograft nude mice. Non-specific inhibition in human BRCA1+/+, BRCA1+/-, and BRCA1-/- breast cancer cells by PARP-1 inhibitors was also observed. Additional mutations occurring during cancer progression may be a culprit, although the exact cause for the resistance of BRCA1-/- breast cancer cells to PARP-1 inhibitors remains elusive. These findings suggest that PARP inhibition may serve as an approach for the prevention of BRCA related breast cancer and may be useful in combination with other chemotherapeutic agents in the treatment of breast cancer.
Collapse
Affiliation(s)
- Joseph A De Soto
- Genetics of Development and Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 10/9N105, 10 Center Drive, Bethesda, MD 20892, USA
| | | |
Collapse
|
30
|
Brugmans L, Kanaar R, Essers J. Analysis of DNA double-strand break repair pathways in mice. Mutat Res 2006; 614:95-108. [PMID: 16797606 DOI: 10.1016/j.mrfmmm.2006.01.022] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2005] [Revised: 01/19/2006] [Accepted: 01/23/2006] [Indexed: 11/26/2022]
Abstract
During the last years significant new insights have been gained into the mechanism and biological relevance of DNA double-strand break (DSB) repair in relation to genome stability. DSBs are a highly toxic DNA lesion, because they can lead to chromosome fragmentation, loss and translocations, eventually resulting in cancer. DSBs can be induced by cellular processes such as V(D)J recombination or DNA replication. They can also be introduced by exogenous agents DNA damaging agents such as ionizing radiation or mitomycin C. During evolution several pathways have evolved for the repair of these DSBs. The most important DSB repair mechanisms in mammalian cells are nonhomologous end-joining and homologous recombination. By using an undamaged repair template, homologous recombination ensures accurate DSB repair, whereas the untemplated nonhomologous end-joining pathway does not. Although both pathways are active in mammals, the relative contribution of the two repair pathways to genome stability differs in the different cell types. Given the potential differences in repair fidelity, it is of interest to determine the relative contribution of homologous recombination and nonhomologous end-joining to DSB repair. In this review, we focus on the biological relevance of DSB repair in mammalian cells and the potential overlap between nonhomologous end-joining and homologous recombination in different tissues.
Collapse
Affiliation(s)
- Linda Brugmans
- Department of Cell Biology and Genetics, Erasmus MC, Dr. Molewaterplein 50, PO Box 1738, Rotterdam 3015GE, The Netherlands
| | | | | |
Collapse
|
31
|
Bramley M, Clarke RB, Howell A, Evans DGR, Armer T, Baildam AD, Anderson E. Effects of oestrogens and anti-oestrogens on normal breast tissue from women bearing BRCA1 and BRCA2 mutations. Br J Cancer 2006; 94:1021-8. [PMID: 16538216 PMCID: PMC2361237 DOI: 10.1038/sj.bjc.6603042] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
There is considerable interest in whether anti-oestrogens can be used to prevent breast cancer in women bearing mutations in the BRCA1 and BRCA2 genes. The effects of oestradiol (E2), tamoxifen (TAM) and fulvestrant (FUL) on proliferation and steroid receptor expression were assessed in normal breast epithelium taken from women at varying risks of breast cancer and implanted into athymic nude mice, which were treated with E2 in the presence and absence of TAM or FUL. Tissue samples were taken at various time points thereafter for assessment of proliferative activity and expression of oestrogen and progesterone receptors (ERα and PgR) by immunohistochemistry. Oestradiol increased proliferation in the breast epithelium from women carrying mutations in the BRCA1/2 genes, those otherwise at increased risk and those at population risk of breast cancer. This increase was reduced by both TAM and FUL in all risk groups. In the absence of E2, PgR expression was reduced in all risk groups but significantly more so in the BRCA-mutated groups. Subsequent E2 treatment caused a rapid, complete induction of PgR expression in the population-risk group but not in the high-risk or BRCA-mutated groups in which PgR induction was significantly delayed. These data suggest that the mechanisms by which E2 induces breast epithelial PgR expression are impaired in BRCA1/2 mutation carriers, whereas those regulating proliferation remain intact. We conclude that early anti-oestrogen treatment should prevent breast cancer in very high-risk women.
Collapse
Affiliation(s)
- M Bramley
- Department of Surgery, Christie Hospital NHS Trust, Manchester M20 4BX, USA
- Clinical Research Department, Christie Hospital NHS Trust, Manchester M20 4BX, USA
| | - R B Clarke
- Clinical Research Department, Christie Hospital NHS Trust, Manchester M20 4BX, USA
- Breast Biology Group, University of Manchester, Christie Hospital NHS Trust, Wilmslow Road, Manchester M20 4BX, UK. E-mail:
| | - A Howell
- CR-UK Department of Medical Oncology, Christie Hospital NHS Trust, Manchester M20 4BX, USA
| | - D G R Evans
- University Department of Medical Genetics and Regional Genetics Service, St Mary's Hospital, Manchester M13 0JH, USA
| | - T Armer
- Clinical Research Department, Christie Hospital NHS Trust, Manchester M20 4BX, USA
| | - A D Baildam
- Department of Surgery, Christie Hospital NHS Trust, Manchester M20 4BX, USA
| | - E Anderson
- Clinical Research Department, Christie Hospital NHS Trust, Manchester M20 4BX, USA
| |
Collapse
|
32
|
Phelan CM, Dapic V, Tice B, Favis R, Kwan E, Barany F, Manoukian S, Radice P, van der Luijt RB, van Nesselrooij BPM, Chenevix-Trench G, Caldes T, de la Hoya M, Lindquist S, Tavtigian SV, Goldgar D, Borg A, Narod SA, Monteiro ANA. Classification of BRCA1 missense variants of unknown clinical significance. J Med Genet 2006; 42:138-46. [PMID: 15689452 PMCID: PMC1735988 DOI: 10.1136/jmg.2004.024711] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND BRCA1 is a tumour suppressor with pleiotropic actions. Germline mutations in BRCA1 are responsible for a large proportion of breast-ovarian cancer families. Several missense variants have been identified throughout the gene but because of lack of information about their impact on the function of BRCA1, predictive testing is not always informative. Classification of missense variants into deleterious/high risk or neutral/low clinical significance is essential to identify individuals at risk. OBJECTIVE To investigate a panel of missense variants. METHODS AND RESULTS The panel was investigated in a comprehensive framework that included (1) a functional assay based on transcription activation; (2) segregation analysis and a method of using incomplete pedigree data to calculate the odds of causality; (3) a method based on interspecific sequence variation. It was shown that the transcriptional activation assay could be used as a test to characterise mutations in the carboxy-terminus region of BRCA1 encompassing residues 1396-1863. Thirteen missense variants (H1402Y, L1407P, H1421Y, S1512I, M1628T, M1628V, T1685I, G1706A, T1720A, A1752P, G1788V, V1809F, and W1837R) were specifically investigated. CONCLUSIONS While individual classification schemes for BRCA1 alleles still present limitations, a combination of several methods provides a more powerful way of identifying variants that are causally linked to a high risk of breast and ovarian cancer. The framework presented here brings these variants nearer to clinical applicability.
Collapse
Affiliation(s)
- C M Phelan
- H Lee Moffitt Cancer Center, 12902 Magnolia Drive, Tampa, FL 33612, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Honrado E, Benítez J, Palacios J. Histopathology of BRCA1- and BRCA2-associated breast cancer. Crit Rev Oncol Hematol 2006; 59:27-39. [PMID: 16530420 DOI: 10.1016/j.critrevonc.2006.01.006] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2005] [Revised: 12/31/2005] [Accepted: 01/12/2006] [Indexed: 11/24/2022] Open
Abstract
Hereditary breast carcinomas that are attributable to BRCA1/2 mutations have their own morphological and immunohistochemical characteristics. BRCA1-associated carcinomas are poorly differentiated infiltrating ductal carcinomas that frequently show morphological features of typical or atypical medullary carcinoma. BRCA2-associated breast carcinomas tend to be of higher grade than sporadic age-matched controls. BRCA1tumors have been found to be more frequently estrogen receptor- and progesterone receptor-negative, and p53-positive than are age-matched controls, whereas these differences are not usually found in BRCA2-associated tumors. In addition, BRCA1- and BRCA2-associated breast carcinomas show a low frequency of HER2 expression. Most BRCA1 breast carcinomas are characterized by the expression of basal (myoepithelial) markers, such as cytokeratin 5/6 and or P-cadherin. These features could be used to distinguish patients who are likely to carry a BRCA1 or BRCA2 germline mutation, thus indicating which gene should be screened for first in families with a high incidence of breast and ovarian cancer.
Collapse
Affiliation(s)
- Emiliano Honrado
- Human Genetics Department, Centro Nacional de Investigaciones Oncológicas (CNIO), Madrid, Spain
| | | | | |
Collapse
|
34
|
Deng CX. BRCA1: cell cycle checkpoint, genetic instability, DNA damage response and cancer evolution. Nucleic Acids Res 2006; 34:1416-26. [PMID: 16522651 PMCID: PMC1390683 DOI: 10.1093/nar/gkl010] [Citation(s) in RCA: 382] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2006] [Accepted: 02/11/2006] [Indexed: 12/11/2022] Open
Abstract
Germline mutations of the breast cancer associated gene 1 (BRCA1) predispose women to breast and ovarian cancers. BRCA1 is a large protein with multiple functional domains and interacts with numerous proteins that are involved in many important biological processes/pathways. Mounting evidence indicates that BRCA1 is involved in all phases of the cell cycle and regulates orderly events during cell cycle progression. BRCA1 deficiency, consequently causes abnormalities in the S-phase checkpoint, the G(2)/M checkpoint, the spindle checkpoint and centrosome duplication. The genetic instability caused by BRCA1 deficiency, however, also triggers cellular responses to DNA damage that blocks cell proliferation and induces apoptosis. Thus BRCA1 mutant cells cannot develop further into full-grown tumors unless this cellular defense is broken. Functional analysis of BRCA1 in cell cycle checkpoints, genome integrity, DNA damage response (DDR) and tumor evolution should benefit our understanding of the mechanisms underlying BRCA1 associated tumorigenesis, as well as the development of therapeutic approaches for this lethal disease.
Collapse
Affiliation(s)
- Chu-Xia Deng
- Genetics of Development and Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 10/9N105, 10 Center Drive, Bethesda, MD 20892, USA.
| |
Collapse
|
35
|
Billack B, Monteiro ANA. BRCA1 in breast and ovarian cancer predisposition. Cancer Lett 2005; 227:1-7. [PMID: 16051027 DOI: 10.1016/j.canlet.2004.11.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2004] [Accepted: 11/01/2004] [Indexed: 12/16/2022]
Abstract
Women carrying one mutated BRCA1 allele are at increased risk of developing breast and ovarian cancer but tumor initiation requires the loss of the wild-type allele indicating that it is a tumor suppressor gene. In the 10 years since the cloning of BRCA1, a function for the gene product in the DNA damage response has been established. However, identifying the exact biochemical activities of BRCA1 has been a more difficult task. Our current understanding suggests that the molecular functions mediated by the terminal ends of BRCA1, which include an E3 ubiquitin ligase activity at the N-terminus and a protein-protein interaction surface at the C-terminus, are critical to the function of this protein in the response to DNA damage.
Collapse
Affiliation(s)
- Blase Billack
- Department of Pharmaceutical Sciences, College of Pharmacy and Allied Health Professions, St John's University, Jamaica, NY 11439, USA
| | | |
Collapse
|
36
|
Lou Z, Minter-Dykhouse K, Chen J. BRCA1 participates in DNA decatenation. Nat Struct Mol Biol 2005; 12:589-93. [PMID: 15965487 DOI: 10.1038/nsmb953] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2005] [Accepted: 05/18/2005] [Indexed: 11/08/2022]
Abstract
The tumor suppressor BRCA1 has an important function in the maintenance of genomic stability. Increasing evidence suggests that BRCA1 regulates cell cycle checkpoints and DNA repair after DNA damage. However, little is known about its normal function in the absence of DNA damage. Here we show that BRCA1 interacts and colocalizes with topoisomerase IIalpha in S phase cells. Similar to cells treated with the topoisomerase IIalpha inhibitor ICRF-193, BRCA1-deficient cells show lagging chromosomes, indicating a defect in DNA decatenation and chromosome segregation. More directly, BRCA1 deficiency results in defective DNA decatenation in vitro. Finally, topoisomerase IIalpha is ubiquitinated in a BRCA1-dependent manner, and topoisomerase IIalpha ubiquitination correlates with higher DNA decatenation activity. Together these results suggest an important role of BRCA1 in DNA decatenation and reveal a previously unknown function of BRCA1 in the maintenance of genomic stability.
Collapse
Affiliation(s)
- Zhenkun Lou
- Department of Oncology, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA
| | | | | |
Collapse
|
37
|
Abstract
Breast carcinoma is the leading cause of cancer incidence, and second in cancer mortality to lung cancer, in women of the Western hemisphere. Germ line mutations in the breast cancer susceptibility gene, BRCA1, is responsible for half of all cases of hereditary breast cancer, which constitutes about 5-10% of all cases of breast cancer. Current hypothesis has ascribed a role for Brca1 in maintaining genomic stability, through its involvement in cellular response pathway to the DNA double-strand breaks (DSB). DNA DSB, which are the most deleterious form of DNA damage, are repaired through a series of coordinated steps embedded in a signal transduction pathway that ultimately ensure the elimination of potentially harmful mutations to the genome. This pathway can be crudely divided into a primary and secondary phase. The primary response phase is initiated by sensor proteins that activate transducer protein kinases Atm and Atr, which target downstream effector proteins, such as Chk1 and Chk2, to elicit the secondary response phase. Brca1 has been intimately linked with various aspects of this signaling pathway. However, the precise role of Brca1 in this process remains unclear. In this review, we will provide a simple model in an attempt to clarify the role of Brca1 during cellular response to DNA DSB.
Collapse
Affiliation(s)
- Nicholas S Y Ting
- Department of Biological Chemistry, University of California at Irvine, 124 Sprague Hall, Irvine, CA 92697, USA
| | | |
Collapse
|
38
|
Musgrove EA, Davison EA, Ormandy CJ. Role of the CDK inhibitor p27 (Kip1) in mammary development and carcinogenesis: insights from knockout mice. J Mammary Gland Biol Neoplasia 2004; 9:55-66. [PMID: 15082918 DOI: 10.1023/b:jomg.0000023588.55733.84] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The cyclin-dependent kinase inhibitor p27 (Kip1) is an important cell cycle regulatory gene in breast cancer, and decreased p27 expression is associated with poor prognosis. Some investigations of its role in mammary development have demonstrated reduced cyclin D1 expression and consequent lack of lobuloalveolar development, but others have found increased cyclin E-Cdk2 activity and increased proliferation balanced by increased apoptosis. It is unclear at present why these apparently divergent results have been obtained. Mice with reduced p27 gene dosage alone do not develop mammary carcinomas but do display substantially shorter tumor latency upon overexpression of erbB2, consistent with a role for p27 as a mammary tumor suppressor gene. In this review we summarize these and other data addressing the role of p27 in normal mammary epithelium and experimental models of mammary carcinogenesis.
Collapse
Affiliation(s)
- Elizabeth A Musgrove
- Cancer Research Program, Garvan Institute of Medical Research, St Vincent's Hospital, Sydney, Australia.
| | | | | |
Collapse
|
39
|
Wong AST, Auersperg N. Ovarian surface epithelium: family history and early events in ovarian cancer. Reprod Biol Endocrinol 2003; 1:70. [PMID: 14609432 PMCID: PMC270003 DOI: 10.1186/1477-7827-1-70] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2003] [Accepted: 10/07/2003] [Indexed: 01/07/2023] Open
Abstract
Ovarian cancer is the most common cause of death from gynecological cancers in the Western world. There are many genetic and environmental factors which can influence a woman's risk of getting ovarian cancer. A strong family history of breast or ovarian cancer is definitely one of the most important and best-defined epidemiological risk factors. This review evaluates current knowledge of hereditary ovarian cancer. Histologic, cytologic and molecular studies on the ovarian surface epithelium (OSE), which is the origin of ovarian epithelial carcinomas, from women with a strong family history for ovarian carcinomas or with a mutation in one of the two known cancer susceptibility genes - BRCA1 and BRCA2, provide a background to facilitate understanding of the early changes in ovarian carcinogenesis. This overview is followed by a discussion of recent hypotheses and research on two questions. First, is there a mutational hotspot of BRCA mutation for ovarian cancer? Second, why do mutations in BRCA1 and BRCA2, which are ubiquitously expressed genes that participate in general cellular activities, lead preferentially to breast and ovarian cancer?
Collapse
Affiliation(s)
- Alice ST Wong
- Department of Zoology, University of Hong Kong, Hong Kong
| | - Nelly Auersperg
- Department of Obstetrics and Gynecology, University of British Columbia, Vancouver, Canada
| |
Collapse
|
40
|
McCarthy EE, Celebi JT, Baer R, Ludwig T. Loss of Bard1, the heterodimeric partner of the Brca1 tumor suppressor, results in early embryonic lethality and chromosomal instability. Mol Cell Biol 2003; 23:5056-63. [PMID: 12832489 PMCID: PMC162231 DOI: 10.1128/mcb.23.14.5056-5063.2003] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The BRCA1 tumor suppressor has been implicated in many cellular pathways, but the mechanisms by which it suppresses tumor formation are not fully understood. In vivo BRCA1 forms a heterodimeric complex with the related BARD1 protein, and its enzymatic activity as a ubiquitin ligase is largely dependent upon its interaction with BARD1. To explore the genetic relationship between BRCA1 and BARD1, we have examined the phenotype of Bard1-null mice. These mice become developmentally retarded and die between embryonic day 7.5 (E7.5) and E8.5. Embryonic lethality results from a severe impairment of cell proliferation that is not accompanied by increased apoptosis. In the absence of p53, the developmental defects associated with Bard1 deficiency are partly ameliorated, and the lethality of Bard1; p53-nullizygous mice is delayed until E9.5. This result, together with the increased chromosomal aneuploidy of Bard1 mutant cells, indicates a role for Bard1 in maintaining genomic stability. The striking similarities between the phenotypes of Bard1-null, Brca1-null, and double Bard1; Brca1-null mice provide strong genetic evidence that the developmental functions of Brca1 and Bard1 are mediated by the Brca1/Bard1 heterodimer.
Collapse
Affiliation(s)
- Ellen E McCarthy
- Department of Anatomy and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
| | | | | | | |
Collapse
|
41
|
Abstract
The BRCA1 gene was identified and cloned in 1994 based its linkage to early onset breast cancer and breast-ovarian cancer syndromes in women. While inherited mutations of BRCA1 are responsible for about 40-45% of hereditary breast cancers, these mutations account for only 2-3% of all breast cancers, since the BRCA1 gene is rarely mutated in sporadic breast cancers. However, BRCA1 expression is frequently reduced or absent in sporadic cancers, suggesting a much wider role in mammary carcinogenesis. Since BRCA1 was cloned in 1994, its molecular function has been the subject of intense investigation. These studies have revealed multiple functions of the BRCA1 that may contribute to its tumor suppressor activity, including roles in: cell cycle progression, several highly specialized DNA repair processes, DNA damage-responsive cell cycle check-points, regulation of a set of specific transcriptional pathways, and apoptosis. Many of these functions are linked to protein:protein interactions involving different portions of the 1,863 amino acid (aa) BRCA1 protein. BRCA1 functions in cell cycle progression and the DNA damage response appear to be regulated by distinct and specific phosphorylation events, but the molecular pathways activated by these phosphorylations are only beginning to be unraveled. In addition, the reason that BRCA1 mutation carriers develop specific tumor types (breast and ovarian cancers in women and possibly prostate cancers in men) is not clearly understood. Elucidation of the precise molecular functions of the BRCA1 gene product will greatly enhance our understanding of the pathogenesis of hereditary as well as sporadic mammary carcinogenesis.
Collapse
Affiliation(s)
- Eliot M Rosen
- Department of Radiation Oncology, Long Island Jewish Medical Center, New York, New York, USA.
| | | | | | | |
Collapse
|
42
|
Abstract
Recent evidence indicates that BRCA1, a gene product associated with breast and ovarian cancer susceptibility, is an important component of the cellular response to DNA damage. Despite being expressed ubiquitously in adult tissues, germline mutations in BRCA1 predispose individuals to breast and ovarian tumors with only minor effects on the predisposition to cancer in other sites. The reason for this tissue specificity of BRCA1 carcinomas must be found if we are to understand fully why these tumors occur and to enable us to design efficient preventive and therapeutic regimens. Here I propose that tissue-specific rates of loss of heterozygosity in the BRCA1 locus could contribute to tissue specificity in tumor development.
Collapse
Affiliation(s)
- Alvaro N A Monteiro
- Department of Cell and Developmental Biology, Weill Medical College of Cornell University, New York, NY 10021, USA.
| |
Collapse
|
43
|
Nadithe V, Rahamatalla M, Finlay WH, Mercer JR, Samuel J. Evaluation of nose-only aerosol inhalation chamber and comparison of experimental results with mathematical simulation of aerosol deposition in mouse lungs. J Pharm Sci 2003; 92:1066-76. [PMID: 12712427 DOI: 10.1002/jps.10379] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In vivo small rodent efficacy testing of new synthetic and biological molecules for the pulmonary route requires an efficient delivery device. For this purpose, a nose-only inhalation chamber was used to deliver aerosolized aqueous compounds to the respiratory tract of mice. The aim of the study was to determine the efficiency of dose delivery and deposition in the lungs of the mice using this chamber. A secondary goal was to compare the experimental lung deposition results with values predicted from mathematical simulation. Experimental tests were conducted by generating aerosols of a radiolabeled formulation of human serum albumin (HSA) with a mass median aerodynamic diameter (MMAD) of 3.9 +/- 0.5 microm and a geometric standard deviation (GSD) of 1.43 +/- 0.05 using PARI LC STAR jet nebulizers. Based on the total activity placed in the nebulizer, the chamber delivered 0.108 +/- 0.027% to the mice and 0.0087 +/- 0.0021% to the lungs of the mice. In vivo lung deposition was found to be 8.19 +/- 3.56% of total activity deposited in the mouse. Mathematical simulation predictions ranged between 5.89 and 4.40% for various breathing patterns, and did not differ significantly from the in vivo results (p > 0.10). These results provide important quantitative information relevant to aerosol delivery experiments in mouse models. Our results also suggest that the nose-only inhalation chamber would benefit from significant changes to increase the efficiency of deposition in mice such that it can be used for nebulization of expensive therapeutic drugs.
Collapse
Affiliation(s)
- Venkatareddy Nadithe
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, Canada, T6G 2N8
| | | | | | | | | |
Collapse
|
44
|
Korhonen L, Brännvall K, Skoglösa Y, Lindholm D. Tumor suppressor gene BRCA-1 is expressed by embryonic and adult neural stem cells and involved in cell proliferation. J Neurosci Res 2003; 71:769-76. [PMID: 12605402 DOI: 10.1002/jnr.10546] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BRCA-1 is a tumor suppressor gene that plays a role in DNA repair and cellular growth control. Here we show that BRCA-1 mRNA is expressed by embryonic rat brain and is localized to the neuroepithelium containing neuronal precursor cells. The expression of BRCA-1 decreases during rat brain development, but BRCA-1 is expressed postnatally by proliferating neuronal precursor cells in the developing cerebellum. Neural stem cells (NSC) prepared from embryonic rat brain and cultured in the presence of epidermal growth factor were positive for BRCA-1. Induction of NSC differentiation resulted in down-regulation of BRCA-1 expression as shown by RNA and protein analyses. In addition to embryonic cells, BRCA-1 is also present in NSC prepared from adult rat brain. In adult rats, BRCA1 was expressed by cells in the walls of brain ventricles and in choroid plexus. The results show that BRCA-1 is present in embryonic and adult rat NSC and that the expression is linked to NSC proliferation.
Collapse
Affiliation(s)
- L Korhonen
- Department of Neuroscience, Neurobiology, Uppsala University, Biomedical Centre, Uppsala, Sweden
| | | | | | | |
Collapse
|
45
|
Bachelier R, Xu X, Wang X, Li W, Naramura M, Gu H, Deng CX. Normal lymphocyte development and thymic lymphoma formation in Brca1 exon-11-deficient mice. Oncogene 2003; 22:528-37. [PMID: 12555066 DOI: 10.1038/sj.onc.1206208] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Breast-cancer-associated gene 1 (BRCA1) is highly expressed in thymus and spleen. In this paper, we have studied lymphocyte development and tumorigenesis in mice carrying mutations in Brca1 and p53. We show that the deletion of Brca1 exon 11 (Brca1-delta11), which disrupts the full-length isoform, but not the short isoform of Brca1, does not interfere with lymphocyte development. This is true irrespective of p53 status, that is, whether it is wild type, heterozygous or homozygous for a null mutation. These data suggest that the expression of Brca1 short isoform alone is enough to maintain normal development of lymphocytes. However, it cannot suppress tumorigenesis as about 30% of Brca1(delta11/delta11)p53(+/-) mice develop thymic lymphoma between 3 and 7 months of age. We demonstrate that p53 plays an essential role in Brca1-associated lymphoma, as all the tumors from Brca1(delta11/delta11)p53(+/-) mice exhibit LOH of p53 and Brca1(delta11/delta11)p53(-/-) mice exhibited accelerated tumorigenesis. We further demonstrate that the Brca1-delta11 deficiency does not affect thymocyte proliferation; however, it increases genetic instability and triggers gamma-irradiation-induced apoptosis. The loss of p53 attenuates apoptosis and allows accumulation of further mutations in Brca1-delta11 thymocytes, eventually leading to thymic lymphoma formation.
Collapse
Affiliation(s)
- Richard Bachelier
- Genetics of Development and Disease Branch, NIDDK, Bethesda, MD, USA
| | | | | | | | | | | | | |
Collapse
|
46
|
Kubista M, Rosner M, Miloloza A, Hofer K, Prusa AR, Kroiss R, Marton E, Hengstschläger M. Brca1 and differentiation. Mutat Res 2002; 512:165-72. [PMID: 12464350 DOI: 10.1016/s1383-5742(02)00063-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Breast cancer is one of the most frequent malignancies affecting women. The human breast cancer gene 1 (BRCA1) gene is mutated in a distinct proportion of hereditary breast and ovarian cancers. Tumourigenesis in individuals with germline BRCA1 mutations requires somatic inactivation of the remaining wild-type allelle. Although, this evidence supports a role for BRCA1 as a tumour suppressor, the mechanisms through which its loss leads to tumourigenesis remain to be determined. Neither the expression pattern nor the described functions of human BRCA1 and murine breast cancer gene 1 (Brca1) can explain the specific association of mutations in this gene with the development of breast and ovarian cancer. Investigation of the role of Brca1 in normal cell differentiation processes might provide the basis to understand the tissue-restricted properties.
Collapse
Affiliation(s)
- Marion Kubista
- AKH-EBO-E6 Division of Prenatal Diagnosis and Therapy, Obstetrics and Gynecology, University of Vienna, Währinger Gürtel 18-20, A-1090, Vienna, Austria
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Ganesan S, Silver DP, Greenberg RA, Avni D, Drapkin R, Miron A, Mok SC, Randrianarison V, Brodie S, Salstrom J, Rasmussen TP, Klimke A, Marrese C, Marahrens Y, Deng CX, Feunteun J, Livingston DM. BRCA1 supports XIST RNA concentration on the inactive X chromosome. Cell 2002; 111:393-405. [PMID: 12419249 DOI: 10.1016/s0092-8674(02)01052-8] [Citation(s) in RCA: 229] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BRCA1, a breast and ovarian tumor suppressor, colocalizes with markers of the inactive X chromosome (Xi) on Xi in female somatic cells and associates with XIST RNA, as detected by chromatin immunoprecipitation. Breast and ovarian carcinoma cells lacking BRCA1 show evidence of defects in Xi chromatin structure. Reconstitution of BRCA1-deficient cells with wt BRCA1 led to the appearance of focal XIST RNA staining without altering XIST abundance. Inhibiting BRCA1 synthesis in a suitable reporter line led to increased expression of an otherwise silenced Xi-located GFP transgene. These observations suggest that loss of BRCA1 in female cells may lead to Xi perturbation and destabilization of its silenced state.
Collapse
Affiliation(s)
- Shridar Ganesan
- The Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Abstract
Centrosome duplication is under precise control and occurs only once in a normal mammalian cell cycle. Disruption of this process causes centrosome amplification, unequal segregation of chromosomes and, ultimately, tumorigenesis. Recent studies indicate that breast cancer suppressor gene 1 (BRCA1) plays an important role in regulating centrosome duplication. BRCA1 is located in the centrosome and binds to gamma-tubulin. It interacts with a variety of proteins that regulate centrosome duplication, including BRCA2, CDK2-Cyclin A, CDK2-Cyclin E, Gadd45, p21, p53 and Rb. Furthermore, targeted disruption of murine BRCA1 results in centrosome amplification, suggesting that BRCA1 serves as a negative regulator for centrosome duplication. This review will examine these data and discuss possible relationships between BRCA1 and its interacting proteins in centrosome duplication.
Collapse
Affiliation(s)
- Chu-Xia Deng
- Genetics of Development and Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 10/9N105, 10 Center Drive, Bethesda, Maryland, MD 20892, USA.
| |
Collapse
|
49
|
Hansen DV, Hsu JY, Kaiser BK, Jackson PK, Eldridge AG. Control of the centriole and centrosome cycles by ubiquitination enzymes. Oncogene 2002; 21:6209-21. [PMID: 12214251 DOI: 10.1038/sj.onc.1205824] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- David V Hansen
- Programs in Chemical Biology and Cancer Biology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, California, CA 94305-5324, USA
| | | | | | | | | |
Collapse
|
50
|
Ae K, Kobayashi N, Sakuma R, Ogata T, Kuroda H, Kawaguchi N, Shinomiya K, Kitamura Y. Chromatin remodeling factor encoded by ini1 induces G1 arrest and apoptosis in ini1-deficient cells. Oncogene 2002; 21:3112-20. [PMID: 12082626 DOI: 10.1038/sj.onc.1205414] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2001] [Revised: 02/08/2002] [Accepted: 02/20/2002] [Indexed: 01/22/2023]
Abstract
Ini1/hsnf5 gene encodes INI1 protein, a chromatin remodeling factor associated with the SWI/SNF complex. In yeast, this complex modifies chromatin condensation to coactivate various transcriptional factors. However, in human, little is known about the SWI/SNF complex and INI1. To elucidate cellular functions of ini1, we constructed a recombinant adenovirus (AdexHA-INI1) capable of overexpressing INI1 in ini1-deficient cells. AdexHA-INI1 produced intranuclear INI1 in three ini1-deficient cell lines, changed their morphology, and decreased the proportion of viable cells. Flow cytometry and a BrdU incorporation assay showed that after the infection, growth of these cells was partially arrested at G1. In two of the three ini1-deficient cell lines, apoptosis was found to occur after the infection, as detected by the presence of cleaved poly (ADP-ribose) polymerase. To determine functional domains of INI1, we constructed plasmids expressing INI1 and its deletion mutants, which were used for a colony formation assay. Repeats 1 and 2 of INI1 were found to be required to suppress the growth of the three ini1-deficient cell lines. The results support the hypothesis that ini1 is a tumor suppressor gene and suggest a novel link between human SWI/SNF chromatin remodeling complex and apoptosis.
Collapse
Affiliation(s)
- Keisuke Ae
- Division of Molecular Genetics, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashimurayama, Tokyo 208-0011, Japan
| | | | | | | | | | | | | | | |
Collapse
|