Epigenetic and clinical impact of SMARCB1 loss in cancer

SMARCB1 缺失对癌症的表观遗传学和临床影响

基本信息

批准号：
8386397
负责人：
Elizabeth J Perlman
金额：
$ 20.53万
依托单位：
LURIE CHILDREN'S HOSPITAL OF CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-07-01 至 2014-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8386397
关键词：
22q11 Address Agreement Attention Biological Assay Cell Line Cell Proliferation Cells ChIP-seq Child Children&apos s Oncology Group Chromatin Remodeling Factor Chromosomes Clinical Clinical Research Clinical Trials Complex Cyclin-Dependent Kinases DNA Methylation Development Disease EZH2 gene Embryo Employee Strikes Epigenetic Process Excision Failure Future Gene Expression Gene Expression Profile Genes Genetic Transcription Histones Human In Vitro Investigation Lead Longitudinal Studies Malignant - descriptor Malignant Neoplasms Measures Mediating Methylation Modeling Modification Mutation Pharmacologic Substance Play Polycomb Proteins RNA Interference RNA methylation Regulation Reporting Repression Rhabdoid Tumor Role SMARCB1 gene Staging Stem cells Survival Rate Testing Therapeutic Intervention Transcriptional Regulation Tumor Cell Line Xenograft procedure cytotoxic embryonic stem cell histone modification human embryonic stem cell in vivo infancy inhibitor/antagonist integrase interactor 1 knock-down member new therapeutic target novel therapeutics overexpression patient population pre-clinical sarcoma therapeutic target tumor

项目摘要

DESCRIPTION (provided by applicant): The SMARCB1 (hSNF5/INI-1) gene encodes the INI-1 protein, a component of the SWI/SNF chromatin remodeling complex. While the SWI/SNF complex is known to play an important role in transcriptional regulation, how it does so is largely unknown. Rhabdoid Tumors (RT) are rare, highly malignant sarcomas of infancy that demonstrate mutation and/or deletion of SMARCB1. We recently reported the global gene expression pattern of RT, and provided evidence that RTs arise within very early progenitor cells during a critical developmental window during which loss of SMARCB1 directly results in striking repression of differentiation and loss of cyclin dependent kinase inhibition. We provide additional evidence that these changes are largely mediated by changes in histone methylation. In this proposal we test our hypothesis that loss of SMARCB1 in early progenitor cells results in a global failure to release the polycomb group mediated repressive H3K27me3 on bivalent genes, resulting in arrested development and abnormal proliferation. Aim 1: To knock-down SMARCB1 within hESC and to measure changes in cell proliferation, differentiation, gene expression and DNA methylation compared with three RT cell lines. We will utilize RNA interference to knock-down SMARCB1 in two hESC and measure changes in proliferation, EZH2 expression, differentiation, and RNA and DNA methylation changes. These will be compared to those features in three RT cell lines. Global RNA and DNA methylation analysis in these studies will be compared with histone modifications in RT detected by global ChIP-SEQ being performed outside of this proposal. Aim 2: To investigate the direct and indirect impact of pharmacologic inhibition of EZH2 on cell proliferation in SMARCB1-deficient cells in vitro and in vivo. EZH2 represents the most important polycomb group protein in humans, and has been shown to be upregulated in a large number of tumors. It is therefore an attractive therapeutic target. We have established an agreement with GlaxoSmithKline for the study of a promising EZH2 inhibitor that is ready for preclinical development. We will perform in vitro cytotoxic assays on the three RT cell lines, and in vivo studies on xenografts created from the same cell lines. Both the in vitro and in vivo studies that are proposed are required prior to our ability to develo early clinical trials. Relevance: With an overall survival rate of 23%, new therapeutic options are urgently needed for RT. If our hypothesis is correct, it may result in novel therapeutic targets fo RTs and the many other tumors that show histone modification or EZH2 overexpression. In addition, it will introduce a unique and important model of epigenetic control of both early embryonic differentiation and tumor development. Long-term, these studies will help to identify the underlying mechanisms by which histone modifications interact with other epigenetic mechanisms. This would then enable the investigation of epigenetic regulation more broadly in different patient populations, developmental stages, and diseases. PUBLIC HEALTH RELEVANCE: This project uses a human tumor, rhabdoid tumor, as a model for investigating the loss of the SMARCB1 gene, a key member of the SWI/SNF chromatin remodeling complex. This has relevance to the mechanisms involved in the very earliest stages of differentiation of embryonic stem cells, and to the development of cancer. Therapeutic intervention may contribute to the treatment of children with rhabdoid tumor as well as a large number of other tumors that show aberrant SWI/SNF function.

描述（由申请人提供）：SMARCB1 (hSNF5/INI-1) 基因编码 INI-1 蛋白，该蛋白是 SWI/SNF 染色质重塑复合物的一个组成部分。虽然已知 SWI/SNF 复合物在转录调控中发挥重要作用，但它如何发挥作用很大程度上还不清楚。未知。横纹肌样瘤 (RT) 是罕见的、高度恶性的婴儿肉瘤，表现出 SMARCB1 突变和/或缺失。我们最近报道了 RT 的整体基因表达模式，并提供了证据表明 RT 在一个关键的发育窗口期间在非常早期的祖细胞中出现，在此期间 SMARCB1 的缺失直接导致分化的显着抑制和细胞周期蛋白依赖性激酶抑制的丧失。我们提供了额外的证据表明这些变化很大程度上是由组蛋白甲基化的变化介导的。在本提案中，我们测试了我们的假设，即早期祖细胞中 SMARCB1 的缺失导致整体无法释放多梳基团介导的二价基因上的抑制性 H3K27me3，从而导致发育停滞和异常增殖。目标 1：敲低 hESC 内的 SMARCB1，并测量与三种 RT 细胞系相比细胞增殖、分化、基因表达和 DNA 甲基化的变化。我们将利用 RNA 干扰敲低两个 hESC 中的 SMARCB1，并测量增殖、EZH2 表达、分化以及 RNA 和 DNA 甲基化变化的变化。这些特征将与三种 RT 细胞系的特征进行比较。这些研究中的全局 RNA 和 DNA 甲基化分析将与在本提案之外进行的全局 ChIP-SEQ 检测到的 RT 组蛋白修饰进行比较。目标 2：在体外和体内研究 EZH2 的药理学抑制对 SMARCB1 缺陷细胞的细胞增殖的直接和间接影响。 EZH2 代表人类最重要的多梳蛋白，并已被证明在大量肿瘤中表达上调。因此，它是一个有吸引力的治疗靶点。我们已与葛兰素史克 (GlaxoSmithKline) 达成协议，研究一种有前途的 EZH2 抑制剂，该抑制剂已准备好进行临床前开发。我们将进行体外细胞毒性测定对三种 RT 细胞系的研究，以及对由相同细胞系创建的异种移植物的体内研究。在我们能够开展早期临床试验之前，需要进行体外和体内研究。相关性：总体生存率为 23%，新的治疗选择急需RT。如果我们的假设正确，它可能会为 RT 和许多其他显示组蛋白修饰或 EZH2 过度表达的肿瘤带来新的治疗靶点。此外，还将介绍一种独特且重要的早期胚胎分化和肿瘤发育的表观遗传控制模型。从长远来看，这些研究将有助于确定组蛋白修饰与其他表观遗传机制相互作用的潜在机制。这将使表观遗传调控在不同患者群体、发育阶段和疾病中进行更广泛的研究成为可能。公共健康相关性：该项目使用人类肿瘤横纹肌样瘤作为研究 SMARCB1 基因缺失的模型，SMARCB1 基因是 SWI/SNF 染色质重塑复合体的关键成员。这与胚胎干细胞分化的最早阶段以及癌症的发展有关。治疗干预可能有助于治疗横纹肌样瘤儿童以及大量显示 SWI/SNF 功能异常的其他肿瘤。