Effects of Brca1 Heterozygosity on Mammary Gland Biology

项目摘要/摘要 BRCA1杂合性对乳腺生物学的影响 生殖系杂合BRCA1突变极大地使女性易患乳腺癌和卵巢癌；然而， 这种效应的组织特异性的基础仍然不清楚。越来越多的证据表明，这 基因突变可能在肿瘤形成前引起乳腺组织的表型变化。揭开 乳腺癌前病变的确切性质和机制将被证明对发育至关重要。 改进了对这种家族性癌症综合征的预防性治疗。不幸的是，这一领域的临床进展 受阻于科学文献中关于哪些乳房种群受到干扰的分歧； 事实上，这个问题是围绕正常细胞组成的更广泛模糊性的一个子例 乳腺。 在这项提案中，我们描述了使用质量细胞术系统地测试我们的假设的计划 BRCA1杂合性诱导一种或多种乳腺细胞类型的异常聚集，并且这些 种群表现出分化和DNA修复表型的改变，这最终使它们 比其他乳腺细胞具有更强的致瘤性。在目标1中，我将使用单细胞分析乳腺细胞群 通过质量细胞术进行蛋白质组学，这将使人们能够高分辨率地了解存在的细胞类型 在整个正常的乳腺发育过程中，这将使我们能够更准确地了解 BRCA1+/-乳腺发育和癌前表型的改变在《目标2》中，我会 从功能上表征分化潜能、激素反应和DNA修复，以评估 BRCA1+/-乳腺细胞是否存在分化障碍和DNA修复缺陷 改变仅限于目标1中频率改变的乳房种群。最后，在目标3中，我将采取 Brugge实验室开发的BRCA1相关乳腺癌发生的新小鼠模型的优势 测试不同的乳腺上皮细胞是否具有不同的致瘤能力。总而言之， 这里提出的实验将极大地提高我们对正常乳腺是如何 以及在BRCA1杂合性背景下它是如何改变的。此外，我将直接向 不同乳房人群的致瘤潜力，从而提供了关于 这种家族性癌症综合征。

Project Summary/Abstract Effects of Brca1 Heterozygosity on Mammary Gland Biology Germline heterozygous BRCA1 mutations hugely predispose women to breast and ovarian cancer; however, the basis for the tissue specificity of this effect remains obscure. Burgeoning evidence suggests that this gene’s mutation may cause phenotypic changes in mammary tissue prior to tumor formation. Uncovering the precise nature and mechanisms of the changes in the precancerous breast will prove vital to developing improved preventative treatments for this familial cancer syndrome. Unfortunately, clinical progress in this field is stymied by disagreements in the scientific literature concerning which mammary populations are perturbed; indeed, this issue is a subcase of the broader ambiguity surrounding the cellular composition of the normal mammary gland. In this proposal, we describe plans to use mass cytometry to systematically test our hypothesis that Brca1 heterozygosity induces the aberrant accumulation of one or more mammary cell types and that these populations display altered differentiation and DNA repair phenotypes which ultimately make them more tumorigenic than other mammary cells. In Aim 1, I will analyze mammary cell populations using single-cell proteomics via mass cytometry, which will enable a high-resolution understanding of the cell types present throughout normal mammary gland development and will allow a more precise understanding of the nature of alterations in the development and premalignant phenotype of Brca1+/- mammary glands. In Aim 2, I will functionally characterize the differentiation potential, hormone responsiveness, and DNA repair to assess whether Brca1+/- mammary cells possess differentiation blocks and deficient DNA repair and whether such alterations are restricted to mammary populations altered in frequency in Aim 1. Finally, in Aim 3, I will take advantage of a novel mouse model developed in the Brugge lab of Brca1-associated breast carcinogenesis to test whether distinct mammary epithelial populations have differing tumorigenic capacity. In sum, the experiments proposed herein will greatly advance our knowledge of how the normal mammary gland is organized and how it is altered in the context of Brca1 heterozygosity. In addition, I will be directly addressing the tumorigenic potential of various mammary populations, thus providing direct evidence of the cell-of-origin in this familial cancer syndrome.