Role of PALB2 in the DNA damage response and breast cancer suppression

PALB2 在 DNA 损伤反应和乳腺癌抑制中的作用

基本信息

批准号：
7741534
负责人：
Bing Xia
金额：
$ 32.37万
依托单位：
UNIV OF MED/DENT NJ-R W JOHNSON MED SCH
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-07-01 至 2014-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7741534
关键词：
Amino Acids Antitumor Drug Screening Assays BRCA1 gene BRCA2 Mutation BRCA2 gene Binding Binding Proteins Biochemical Biological Assay Breast C-terminal Canada Cell division Cells China Chromatin Chromatin Structure Clinical Complex Cytokinesis DNA Damage DNA Double Strand Break DNA damage checkpoint Development Enzymes Epithelial Cells Exons Fanconi&apos s Anemia Female Finland Genes Genetic Recombination Genome Germ-Line Mutation Human Hypermethylation Knock-out Knockout Mice Knowledge Lead Loss of Heterozygosity Male mammary gland Malignant Neoplasms Malignant neoplasm of ovary Malignant neoplasm of pancreas Mammary Neoplasms Mammary gland Mediating Modeling Molecular Mutate Mutation N-terminal Names Nephroblastoma Nuclear Operative Surgical Procedures Ovarian Pathway interactions Patients Phase Phenotype Phosphorylation Phosphorylation Site Play Post-Translational Protein Processing Prostate Protein Binding Proteins Risk Role Series Solid Neoplasm Spain Structure TP53 gene Testing Translating Tumor Suppression Tumor Suppressor Proteins United Kingdom United States WD Repeat base cancer cell crosslink early childhood homologous recombination in vitro Assay insight malignant breast neoplasm mouse model novel novel therapeutics pre-clinical promoter protein function public health relevance repaired response tumor tumorigenesis

项目摘要

DESCRIPTION (provided by applicant): Heterozygous germline mutations in BRCA2 predispose female carriers to breast cancer and also lead to increased risks of ovarian, male breast, prostate, and pancreatic cancers. Biallelic germline BRCA2 mutations cause the D1 subtype of Fanconi anemia (FA-D1). BRCA2 is a very large protein that functions, at least in part, as a guardian of genome integrity. We recently identified a novel protein of 1,186 amino acids, which we named PALB2, as a major BRCA2-binding protein, and established that PALB2 is required for BRCA2 functions in the DNA damage response. We further discovered that the PALB2 gene, like BRCA2, is also mutated in breast cancer and Fanconi anemia (FA-N). Thus, we hypothesize that PALB2 functions as a tumor suppressor by enabling BRCA2 functions in the genome integrity control and tumor suppression. We have shown that PALB2 plays an essential role in tethering BRCA2 to chromatin structures and thus enables BRCA2 functions in the DNA damage response, e.g. HR, S phase DNA damage check point, and interstrand crosslink (ICL) repair. However, the mechanistic details as to how PALB2 carries out its functions and how its functions are regulated remain to be elucidated. In this proposal, we plan to carry out comprehensive structure-function analysis, including biochemical purification, cell-based assays, and in vitro assays, to further define the mechanisms of PALB2 DNA damage response functions. Furthermore, we propose to generate conditional PALB2 knockout mouse models to directly test our hypothesis that PALB2 functions as a tumor suppressor in mammary epithelial cells by regulating the function of BRCA2. The following questions will be asked: 1) Does PALB2 inactivation in breast epithelial cells lead to mammary tumor formation? 2) Does p53 play a role in PALB2-mediated tumor suppression, given that p53 and BRCA2 function synergistically to suppress breast cancer? 3) Is PALB2 a haploinsufficient breast cancer suppressor, given that little evidence of loss of heterozygosity (LOH) has been found in PALB2-associated human breast tumors? 4) Does PALB2 suppress tumorigenesis in the mammary gland solely through its support of BRCA2 function? PUBLIC HEALTH RELEVANCE: The proposed studies will generate important insights into the operation of the BRCA1-PALB2- BRCA2 genome integrity control pathway that is crucial for the suppression of breast cancer and a number of other malignancies. The knowledge that will be gained from the proposed efforts may potentially translate into new therapeutic strategies to selectively target and eliminate cancer cells by exploiting their inability to repair certain types of DNA damage, e.g. double strand breaks, interstrand crosslinks, etc. Finally, in the longer term the mouse models generated and characterized here may prove useful for pre-clinical testing of cancer drugs.

描述（由申请人提供）：BRCA2中的杂合性种系突变使雌性携带者患乳腺癌，并导致卵巢，雄性乳房，前列腺和胰腺癌的风险增加。双重生殖线BRCA2突变引起Fanconi贫血的D1亚型（FA-D1）。 BRCA2是一种非常大的蛋白质，至少部分作为基因组完整性的监护人。我们最近确定了一种新型的蛋白质，其中1,186个氨基酸将其命名为PALB2，是一种主要的BRCA2结合蛋白，并确定在DNA损伤响应中BRCA2功能所必需的PALB2是必需的。我们进一步发现，PALB2基因（如BRCA2）也在乳腺癌和fanconi贫血（FA-N）中突变。因此，我们假设PALB2通过在基因组完整性控制和肿瘤抑制中启用BRCA2功能来充当肿瘤抑制器。我们已经表明，PALB2在将BRCA2绑定到染色质结构中起着至关重要的作用，因此可以在DNA损伤响应中启用BRCA2功能，例如HR，S相DNA损伤检查点和链间交联（ICL）修复。但是，有关PALB2如何执行其功能以及如何调节其功能的机械细节仍尚待阐明。在此提案中，我们计划进行全面的结构功能分析，包括生化纯化，基于细胞的测定和体外测定，以进一步定义PALB2 DNA损伤响应函数的机制。此外，我们建议生成有条件的PALB2敲除小鼠模型，以直接检验我们的假设，即PALB2通过调节BRCA2的功能，在乳腺上皮细胞中充当肿瘤抑制器。将提出以下问题：1）乳腺上皮细胞中的PALB2是否会导致乳腺肿瘤形成？ 2）p53是否在PALB2介导的肿瘤抑制中起作用，鉴于p53和BRCA2在抑制乳腺癌方面发挥作用？ 3）PALB2是否在与PALB2相关的人类乳腺肿瘤中发现的杂合性丧失（LOH）的证据很少？ 4）PALB2是否仅通过其对BRCA2功能的支持来抑制乳腺中的肿瘤发生？公共卫生相关性：拟议的研究将对BRCA1-PALB2-BRCA2基因组完整性控制途径的运作产生重要的见解，这对于抑制乳腺癌和许多其他恶性肿瘤至关重要。从提出的努力中获得的知识可能会可能转化为新的治疗策略，以通过利用其修复某些类型的DNA损伤（例如最后，从长远来看，此处生成和表征的小鼠模型可能对癌症药物的临床前测试有用。