Intratumor heterogeneity in BRCA1-mutated breast cancer metastasis

摘要 转移继续导致绝大多数乳腺癌相关死亡，因为转移 人们对这一过程知之甚少，也不存在有效抑制它的疗法。患有BRCA1的女性 突变会以很高的比率发展为最具侵袭性和高度转移性的基底样乳腺癌。尽管 与基底上皮细胞相似，最近的研究发现腔前体细胞是一种 在基底细胞样乳腺癌中经历恶变。本文件中包含的初步测序数据 来自同一细胞基因表达和染色质可及性表观遗传学分析的建议 基底细胞样乳腺癌，显示腔内祖细胞存在多种分化状态。 肿瘤。此外，几种肿瘤细胞状态似乎具有独特的DNA拷贝数突变 签名。这些观察结果引发了这样的问题：特定的分化状态是否参与了 转移和IF突变驱动分化和转移的轨迹。 研究细胞分化状态和突变细胞亚群的转移潜能 在肿瘤方面，拟议的研究将包括以下方法学步骤：1)收获 自发产生BRCA1和P53突变的小鼠肿瘤，2)将肿瘤细胞注射到小鼠体内产生 转移复制，3)使用小鼠菌株特异性抗体分离转移细胞，4)裂解 转移细胞和原始乳腺肿瘤细胞与a)基因表达的平行单细胞图谱 染色质可及性分析和b)定制的高分辨率突变面板，5)数据集成以 结合突变、表观遗传染色质状态和基因表达的贡献，6)计算 转移细胞与原始肿瘤细胞的比较。这项研究有望揭示分子标记 它们定义了BRCA1和p53突变肿瘤中的转移细胞，以启发转移抑制治疗。 这项研究将由一名在分子病理学和系统生物学方面受过大量培训的学生进行。 世卫组织希望继续她的癌症基因组学和生物信息学培训。实验动物工作人员将提供协助 对于动物工作，生物信息学主任将指导计算分析和统计测试，以及 教师顾问/赞助商将监督实验和对结果的解释。学生们将密切合作 与赞助商和生物信息学合作者一起学习尖端基因组学的正确使用和 生物信息学工具推进乳腺癌转移领域。此外，学生还将获得 职业发展机会，如参加会议、指导本科生和 教授暑期课程，为她在癌症相关领域的博士后职位做准备。

Abstract Metastasis continues to cause the vast majority of breast cancer related deaths because the metastatic process is poorly understood and therapies for effectively inhibiting it do not exist. Women with BRCA1 mutations develop the most aggressive, and highly metastatic basal-like breast cancer at a high rate. Despite resembling basal epithelial cells, recent studies have identified the luminal progenitor as the cell type which undergoes malignant transformation in basal-like breast cancer. Preliminary sequencing data included in this proposal, from same-cell gene expression and chromatin accessibility epigenetics assay in a mouse model of basal-like breast cancer, reveal the presence of several differentiation states of luminal progenitor cells within the tumor. Additionally, several tumor cell states appear to have unique DNA copy-number mutational signatures. These observations prompt the questions of whether a particular differentiation state is involved in metastasis and if mutations drive the differentiation and metastasis trajectory. To investigate the metastatic potentials of the cellular differentiation states and mutational cell subpopulations in the tumors, the proposed study will consist of the following methodological steps: 1) harvesting spontaneously generated Brca1&p53-mutant mouse tumors, 2) injection of tumor cells into mice to generate metastasis replicates, 3) isolation of metastatic cells using mouse strain-specific antibodies, 4) splitting of metastatic cells and original mammary tumor cells for parallel single cell profiling with a) gene expression and chromatin accessibility assay and b) custom-built high-resolution mutation panel, 5) data integration to incorporate the contribution of mutations, epigenetic chromatin states, and gene expression, 6) computational comparison of metastatic cells to original tumor cells. This study is expected to reveal the molecular markers which define metastatic cells in Brca1&p53-mutant tumors to inspire metastasis inhibiting therapy. This study will be carried out by a student with substantial training in molecular pathology and systems biology who wishes to further her cancer genomics and bioinformatics training. Laboratory animal personnel will assist with animal work, the bioinformatics director will guide the computational analysis and statistical tests, and the faculty advisor/sponsor will oversee experiments and interpretations of results. The student will work closely with the sponsor and the bioinformatics collaborator to learn the proper use of cutting edge genomics and bioinformatics tools to advance the breast cancer metastasis field. Additionally, the student will be given professional development opportunities such as attending conferences, mentoring undergraduates, and teaching a summer course to prepare her for a post-doctoral position in a cancer-related field.