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Dissecting the Mechanism of Polycomb Eviction by the BAF Complex

剖析 BAF 复合体驱逐 Polycomb 的机制

基本信息

批准号：
10017659
负责人：
Sherry Ginging Lin
金额：
$ 6.64万
依托单位：
STANFORD UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-12-21 至 2022-12-20
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10017659
关键词：
ATP phosphohydrolase Affect Binding Biochemical Biological Assay Bromodomain Catalytic Domain Cell Lineage Cells Cellular Assay Chemicals Chromatin Chromatin Remodeling Factor Clinical Trials Complex Data Databases Defect Development Disease ES Cell Line Gene Expression Genes Genetic Transcription Genomics Goals Human Impairment In Vitro Individual Malignant - descriptor Malignant Neoplasms Measures Mediating Methods Missense Mutation Mus Mutate Mutation NKX2H gene Oncogenes Oncogenic PRC1 Protein Patients Point Mutation Polycomb Protein Region Proteins Recurrent Malignant Neoplasm Research Rhabdoid Tumor Role Sampling Testing Transcriptional Activation Tumor Suppressor Proteins cancer genome cancer therapy cancer type cell type chromatin immunoprecipitation chromatin modification chromatin remodeling combinatorial embryonic stem cell genome-wide genomic locus histone modification in vivo inhibitor/antagonist mutant new therapeutic target novel null mutation programs rare cancer recruit therapeutic development tool tumorigenesis

项目摘要

PROJECT SUMMARY Thousands of cancer samples sequenced over the past decade have revealed that the chromatin remodeler complex, mSWI/SNF (BAF), is mutated in 20% of all cancers. How these mutations in BAF contribute to tumorigenesis is poorly understood, in part because the roles and functions of individual BAF subunits are not well characterized. Studies are further complicated by the combinatorial diversity of the BAF complex both within and across cell types. Together, these factors have made it difficult to define the mechanistic contribution of BAF mutations to the cancer, despite the abundance of cancer genome data. My research in the Crabtree lab will utilize a rapid, reversible assay that combines chemical-induced proximity and chromatin immunoprecipitation (ChIP) to inducibly recruit BAF to a specific genomic locus in living cells and measure immediate downstream effects. Developing this assay has been a major step forward in studying the BAF complex in vivo, as observations from previous studies in vitro have not always held up in living cells. Using this assay, our lab discovered that one mechanism by which BAF remodels chromatin is by evicting Polycomb repressive complexes (PRCs) from chromatin. Indeed, mutated BAF complexes that are catalytically inactive or found in malignant rhabdoid tumors (MRTs) are unable to evict PRCs from chromatin. Importantly, MRT patients have responded positively to PRC inhibitors in clinical trials. Thus, at least in the case of MRTs, disrupting BAF's PRC eviction function contributes to a cancer state that is treatable by PRC inhibitors. MRT is a rare cancer in which 100% of disease cases contain a null mutation in a single BAF subunit. For the vast majority of the 20% of all cancers involving BAF mutations, mutations are rather nonspecific to a particular cancer type. In this research plan I will utilize our lab's in vivo assay for studying chromatin remodelers, biochemical and genomics methods, and cancer mutation data to (1) define all BAF subunits required for PRC opposition, especially via PRC eviction; and (2) define the range of BAF subunit mutations found in cancers which produce a mutant BAF complex that cannot evict PRC from chromatin. This is an important question to answer because patients carrying such mutations that impair BAF-mediated PRC eviction would potentially respond positively to PRC inhibitors. Thus, results from this study will immediately identify potential novel cancer subsets treatable with PRC inhibitors. More broadly, understanding the critical opposition between BAF and Polycomb will identify new targets for therapeutic development.

项目概要过去十年对数千个癌症样本进行测序表明，染色质重塑因子 mSWI/SNF (BAF) 复合体在 20% 的癌症中发生突变。 BAF 中的这些突变如何促成人们对肿瘤发生知之甚少，部分原因是单个 BAF 亚基的作用和功能尚不明确。特征良好。 BAF 复合体的组合多样性使研究变得更加复杂在细胞类型内和细胞类型之间。这些因素加在一起使得很难定义其机制。尽管癌症基因组数据丰富，但 BAF 突变对癌症的贡献。我的研究在 Crabtree 实验室将利用一种快速、可逆的检测方法，将化学诱导的邻近性和染色质结合起来免疫沉淀 (ChIP) 可诱导将 BAF 招募到活细胞中的特定基因组位点并测量直接的下游影响。开发这种检测方法是研究 BAF 的重要一步体内情况很复杂，因为之前体外研究的观察结果并不总是在活细胞中成立。使用通过这项检测，我们的实验室发现 BAF 重塑染色质的一种机制是驱逐 Polycomb 来自染色质的抑制复合物（PRC）。事实上，突变的 BAF 复合物没有催化活性或在恶性横纹肌样瘤 (MRT) 中发现的 PCR 无法从染色质中驱逐 PRC。重要的是，捷运在临床试验中，患者对 PRC 抑制剂有积极反应。因此，至少就捷运而言，破坏 BAF 的 PRC 驱逐功能会导致 PRC 抑制剂可治疗的癌症状态。捷运是一种罕见的癌症，其中 100% 的疾病病例在单个 BAF 亚基中含有无效突变。对于广大 20% 的所有癌症中，大多数涉及 BAF 突变，突变对于特定的基因来说是相当非特异性的。癌症类型。在这个研究计划中，我将利用我们实验室的体内测定来研究染色质重塑剂，生化和基因组学方法以及癌症突变数据 (1) 定义 PRC 所需的所有 BAF 亚基反对，特别是通过中华人民共和国驱逐； (2) 定义癌症中发现的 BAF 亚基突变的范围其产生不能将 PRC 从染色质中驱逐的突变 BAF 复合物。这是一个重要的问题答案是因为携带此类突变的患者可能会损害 BAF 介导的 PRC 驱逐对 PRC 抑制剂有积极反应。因此，这项研究的结果将立即确定潜在的新颖性可使用 PRC 抑制剂治疗的癌症亚型。更广泛地说，理解 BAF 之间的批评性反对 Polycomb 将确定治疗开发的新目标。