Regulation of p53 by BRCA1 in Breast Cancer

BRCA1 在乳腺癌中对 p53 的调节

• 批准号: 8267245
• 负责人: Joy Chieh-Yu Lin
• 金额: $ 5.39万
• 依托单位: UNIVERSITY OF CALIFORNIA RIVERSIDE
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8267245
• 关键词: Abnormal Cell; Acetylation; Affect; Apoptosis; BRCA1 gene; Biological Assay; Biological Process; Breast; Breast Cancer Cell; CREB-binding protein; Cancer-Predisposing Gene; Cell Aging; Cell Cycle Checkpoint; Cells; Cellular Stress; DNA Binding; DNA Damage; DNA Repair; Data; Defect; EP300 gene; Embryo; Event; Fibroblasts; Frequencies; Gene Targeting; Genes; Genetic Transcription; Genome Stability; Germ-Line Mutation; Growth; In Vitro; Individual; Lead; Link; Lysine; Maintenance; Malignant Neoplasms; Mammary Tumorigenesis; Mediating; Molecular; Mus; Mutation; Pathogenesis; Pathway interactions; Phosphorylation; Play; Post-Translational Protein Processing; Process; Proteins; RNA Interference; Recruitment Activity; Regulation; Research Design; Role; Specificity; Staining method; Stains; Stress; Testing; Transcriptional Activation; Transcriptional Regulation; Tumor Suppressor Genes; Tumor Suppressor Proteins; beta-Galactosidase; cancer risk; carcinogenesis; chromatin remodeling; cofactor; design; effective therapy; high risk; human CREBBP protein; improved; in vivo; insight; interest; malignant breast neoplasm; new therapeutic target; novel; overexpression; promoter; public health relevance; research study; response; senescence

DESCRIPTION (provided by applicant): The overall frequency of p53 mutation in breast cancer is much lower compared to other cancers despite a high risk of breast cancer associated with p53 germ-line mutations. This implicates the importance of the inactivation of wild type p53 regulation in breast cancer and mechanisms other than mutation that inactivate p53 need to be characterized. Recently, it was found that BRCA1 is required for maintenance of high p53 acetylation in response to DNA damage in breast cancer cells (preliminary data). As p53 acetylation has been linked to cell senescence, the proposed study is intended to test the role of BRCA1 in p5S-mediated cell senescence in breast cancer. Hypothesis: BRCA1 may induce cell senescence through modulation of p3OO-dependent p53 acetylation in breast cancer cells. This study will examine whether BRCA1-mediated p53 activation is perturbed through disruption of p53 acetylation. Mounting data support a role for p53 in mammary tumorigenesis but the role of p53 in BRCA1-mediated carcinogenesis is still unclear. The long-term objectives are to identify novel relationships between p53 and BRCA1 in breast cancer which will improve our understanding of the pathogenesis of breast cancer, potentially revealing new therapeutic targets to design more specific and effective therapy. Specific Aims: (1) Determine the effect of BRCA1 on p53-p300 interaction and on p53 acetylation. (2) Define the role of the modulation of p53 acetylation by BRCA1 in p53-dependent transcription. (3) Determine the function of the modulation of p53 acetylation by BRCA1 in cell senescence. Study design: RNAi and overexpression studies will be used to characterize how BRCA1 affect p5S-p300 interaction and p53 acetylation in breast cancer cells. ChIP assays and transcriptional activation assays on p21/bax promoter in the presence/absence of p53, p3OO or BRCA1 will be used to dissect the functional connections between those proteins and to determine the sequence of events leading to p53-mediated transcriptional activation. Lastly, RNAi and overexpression approaches will be used to characterize p53-mediated cell senescence induced by BRCA1 using beta- galactosidase staining which is a marker of senescence. PUBLIC HEALTH RELEVANCE: This study is directly relevant to cancer as both p53 and BRCA1 are important tumor suppressors. This study is unique because most studies focus on mutations in tumor suppressor genes while it points out the importance of wild-type p53 regulation in breast cancer and define a novel pathway other than mutations that lead to p53 inactivation. These novel links between BRCA1 and p53 will help identify those individuals at increased breast cancer risk and to devise more specific therapies.

描述（由申请人提供）：尽管与p53种系突变相关的乳腺癌风险很高，但乳腺癌中p53突变的总频率比其他癌症要低得多。这意味着需要表征野生型p53调节在乳腺癌中灭活p53调节的重要性，而突变除了突变，需要表征灭活p53。最近，发现BRCA1是响应于乳腺癌细胞中DNA损伤的高p53乙酰化所必需的（初步数据）。由于p53乙酰化与细胞衰老有关，因此拟议的研究旨在测试BRCA1在P5S介导的细胞衰老中在乳腺癌中的作用。假设：BRCA1可能通过调节乳腺癌细胞中p3oo依赖性p53乙酰化来诱导细胞衰老。这项研究将检查BRCA1介导的p53激活是否因p53乙酰化的破坏而受到干扰。安装数据支持p53在乳腺肿瘤发生中的作用，但是p53在BRCA1介导的癌变中的作用尚不清楚。长期目标是确定乳腺癌中p53和BRCA1之间的新型关系，这将提高我们对乳腺癌发病机理的理解，并有可能揭示新的治疗靶标，以设计更具体和有效的治疗。具体目的：（1）确定BRCA1对P53-P300相互作用和p53乙酰化的影响。 （2）定义了BRCA1在p53依赖性转录中对p53乙酰化调节的作用。 （3）确定BRCA1在细胞衰老中通过BRCA1调节的调节功能。研究设计：RNAi和过表达研究将用于表征BRCA1如何影响乳腺癌细胞中P5S-P300相互作用和p53乙酰化。在存在/不存在p53，p3OO或BRCA1的情况下，对P21/BAX启动子上的CHIP分析和转录激活分析将用于剖析这些蛋白质之间的功能连接，并确定导致p53介导的转录激活的事件的顺序。最后，RNAi和过表达方法将用于表征BRCA1使用β-乳糖苷酶染色诱导的p53介导的细胞衰老，这是衰老的标志。 公共卫生相关性：这项研究与癌症直接相关，因为p53和BRCA1都是重要的肿瘤抑制剂。这项研究是独一无二的，因为大多数研究都集中在肿瘤抑制基因的突变，同时指出了野生型p53调节在乳腺癌中的重要性，并定义了导致p53失活的突变以外的新途径。 BRCA1和p53之间的这些新型联系将有助于确定那些患有乳腺癌风险增加的人并设计更具体的疗法。