Deciphering the mechanism underlying BRCA1 breast cancer development

项目摘要/摘要 遗传性BRCA1突变在受影响的家庭中经常导致高频率的乳腺癌和卵巢癌。 这项建议旨在阐明在无肿瘤、BRCA1突变的月经初潮后发生的关键步骤 乳腺上皮细胞，对未来BRCA1乳腺癌(BRCA)的发展起着重要作用。 我们公布的数据和正在进行的工作表明，存在一系列相互关联的生化步骤 当中断时，会导致表面上看正常的BRCA1突变的乳腺上皮细胞转化 进入一种异常的、去分化的、异常原始的、可能是癌前状态。此更改涉及 一组6个特定基因中任何一个成员的功能丧失，这会转化为DNA的崩溃 损害控制，进而促进乳腺上皮细胞分化的崩溃。在乳腺细胞中 这些基因通常在功能上相互交流，就像它们是生物学上的组件一样 部分致力于抑制BRCA的重要途径。事实上，他们的蛋白质产品形成了一种独特的 也包含BRCA1肿瘤抑制蛋白p220的分子复合体，该复合体作用于 以表明它在这样一条途径中扮演重要角色的方式。 在其他6个复合体成员(BRG1、FANCD2、CtIP、Numb、HES-1和BARD1)中，一些(例如FancD2， BRG1)在散发性BRCA中发生体细胞突变。另一种(Numb)是动物中已知BRCA抑制子， 一个正常干细胞增殖的支持者，6个中至少有5个必须存在并与p220结合 整个复合体形成和乳腺上皮分化正常进行。我们的工作也在进行中 这表明这个复合体的完整性是防止BRCA1 BRCA发展所必需的。 拟议中的研究将测试这一假设的正确性以及这种生理上的重要性 路径，使用尖端方法的组合。将包括一项努力，以测试)血统 乳腺上皮细胞DNA损伤修复失败与乳腺上皮细胞脱分化及预后的关系 MEC去分化与BRCA1肿瘤发生之间的关系以及b)破译 这些事件之间的相互关系。 这些努力的一个主要组成部分将是应用单细胞RNAseq来评估上述 谱系关系与聚焦乳腺上皮的基因组CRISPR和蛋白质过表达筛查 检测参与BRCA1、BRCA发育的这些重要步骤的单个蛋白质。我们将使用 在这些实验中新开发的小鼠模型。

Project Summary/Abstract Inherited BRCA1 mutations very often result in high frequency breast and ovarian cancer in affected families. This proposal is aimed at illuminating key steps that occur after menarche in tumor-free, BRCA1-mutated mammary epithelium and contribute in a major way to future BRCA1 breast cancer (BrCa) development. Our published data and work in progress suggest the existence of a series of interrelated biochemical steps that, when interrupted, result in the conversion of ostensibly normal, BRCA1- mutated breast epithelial cells into an abnormal, dedifferentiated, unusually primitive, and likely pre-malignant state. This change involves the loss of function of any member of a group of 6 particular genes which translates into a breakdown in DNA damage control which, in turn, promotes a breakdown in mammary epithelial differentiation. In breast cells these genes normally communicate with one another, functionally, as if they were components of a biologically important pathway dedicated, in part, to BrCa suppression. Indeed, their protein products form a distinct molecular complex which also contains the BRCA1 tumor suppressor protein, p220, and this complex operates in ways that suggest a major role for it in such a pathway. Among the 6 other complex members (BRG1, FancD2, CtIP,NUMB, HES-1, and BARD1), some (e.g. FancD2, BRG1) are somatically mutated in sporadic BrCa. Another (Numb) is a known BrCa suppressor in animals and a supporter of normal stem cell proliferation, and at least 5 of the 6 must be present and bind to p220 for the entire complex to form and mammary epithelial differentiation to proceed normally. Our work in progress also suggests that the integrity of this complex is required to prevent BRCA1 BrCa from developing. The proposed research will test the validity of this hypothesis along with the physiological importance of such a pathway, using a combination of cutting edge methods. Included will be an effort to a) test for lineage relationships between failed mammary epithelial cell (MEC) DNA damage repair and MEC dedifferentiation and between MEC dedifferentiation and BRCA1 tumor development and b) to decipher the mechanisms governing the interrelationships of these events. A major component of these efforts will be the application of single cell RNAseq to assess the above-noted lineage relationships and mammary epithelium- focused genomic CRISPR and protein overexpression screens to detect individual proteins that participate in these important steps in BRCA1 BrCa development. We will use a newly developed mouse model in these experiments.!