PROJECT 4: ELUCIDATING MECHANISMS OF HISTONE H3K36 DYSREGULATION BY ONCOHISTONES

项目 4：阐明肿瘤蛋白引起的组蛋白 H3K36 失调的机制

• 批准号: 10269907
• 负责人: Peter W Lewis
• 金额: $ 19.95万
• 依托单位: ROCKEFELLER UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-09 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10269907
• 关键词: Affect; Animals; Astrocytoma; Binding; Biochemical; Biochemistry; Biological Assay; Bone neoplasms; Brain Stem Glioma; CRISPR/Cas technology; Cancer Biology; Cancer Model; Cell Differentiation process; Cell Proliferation; Cells; Chemistry; Chondroblastoma; Chromatin; Clinical; Complex; CpG Islands; DNA Methylation; Development; Diagnostic; Diffuse; EZH2 gene; Elements; Enhancers; Enzymes; Ependymoma; Epigenetic Process; Foundations; Frequencies; Gene Expression; Gene Silencing; Genes; Genetic Screening; Genomics; Giant cell tumor of bone; Glioma; Goals; Health; Histone H3; Histones; Human; In Vitro; Investigation; Kinetics; Lead; Malignant - descriptor; Malignant Neoplasms; Mediating; Methods; Methylation; Methyltransferase; Modeling; Molecular; Molecular Chaperones; Molecular Target; Mutation; Pathogenicity; Pathway interactions; Patients; Phenotype; Polycomb; Positioning Attribute; Post-Translational Protein Processing; Post-Translational Regulation; Posterior Fossa; Regulation; Repression; Role; Sampling; Squamous cell carcinoma; Structure-Activity Relationship; Surface; System; Testing; Therapeutic; Therapeutic Intervention; Toxic effect; Transcript; Undifferentiated; Work; base; big gastrin; chromatin modification; design; disease diagnosis; effective therapy; gene repression; genome-wide; histone methylation; in vivo; innovation; insight; interdisciplinary approach; member; mutant; novel; oncohistone; prevent; programs; recruit; sarcoma; sensor; theories; therapeutic development; tumor; tumorigenesis; tumorigenic

SUMMARY: The known histone H3K36-directed methyltransferases are essential for normal animal development and are frequently dysregulated in human cancers. We have found that high-frequency histone H3 mutations (oncohistones) exploit normal chromatin-based regulatory mechanisms, including H3K36 methylation, to drive tumorigenesis. Previously, we found that H3.3 G34 oncohistones selectively block SETD2-mediated H3K36 methylation and affect the activity of gene enhancers that results in aberrant cellular differentiation and proliferation. Moreover, we found that the H3 K36M oncohistone promotes genome-wide changes in histone and DNA methylation through competitive inhibition of NSD1/2 and SETD2 enzymes. We will leverage and extend our preliminary findings to define the mechanisms by H3.3 G34 and H3 K36M oncohistones achieve pro-tumorigenic gene expression programs through misregulation of H3K36 methylation. We will employ a multi-disciplinary approach that integrates biochemical, genomic, and molecular methods to enhance our understanding of K36M and G34 oncohistones and apply our understanding toward diagnostic and therapeutic applications. Specifically, we will: i) identify the changes in chromatin landscape by histone mutations using cell-based systems and patient tumor samples; and ii) characterize misregulated developmental programs that help establish tumorigenesis. These studies will provide guidance for the development of therapeutic strategies designed to ameliorate the pathogenic effects of NSD1/2 and histone H3 mutations in human cancers. We will also extend our findings to elucidate the mechanisms by which NSD1 and H3 K36M mutations alter the chromatin landscape in squamous cell carcinomas (Aim 1). We will define the mechanisms of by which G34 mutations alter chromatin modifications and gene expression, and we will define the role of H3.3 chaperone pathways in mediating G34 phenotypes (Aim 2). Additionally, we have found that H3K36 methylation opposes PRC2 activity, thus preventing Polycomb-mediated gene repression. We will now leverage these biochemical findings to determine the function of the EZH2 H3K36-binding pocket in different tumorigenesis models (Aim 3). Expected results from our study will lead us formulate novel theories and provide crucial mechanistic insights of these oncohistones which can be readily tested in in vivo cancer models (Project 1,2) and in vitro chemistry platforms (Project 3). To accomplish these aims, Project 4 also requires close interactions with both Cores.

摘要：已知的组蛋白 H3K36 定向甲基转移酶对于正常动物发育至关重要，并且在人类癌症中经常失调。我们发现高频组蛋白 H3 突变（癌组蛋白）利用正常的基于染色质的调节机制（包括 H3K36 甲基化）来驱动肿瘤发生。此前，我们发现 H3.3 G34 癌组蛋白选择性阻断 SETD2 介导的 H3K36 甲基化并影响基因增强子的活性，从而导致异常的细胞分化和增殖。此外，我们发现 H3 K36M 癌组蛋白通过 NSD1/2 和 SETD2 酶的竞争性抑制促进组蛋白和 DNA 甲基化的全基因组变化。我们将利用并扩展我们的初步研究结果来定义 H3.3 G34 和 H3 K36M 癌组蛋白通过 H3K36 甲基化的错误调节实现促肿瘤基因表达程序的机制。我们将采用整合生化、基因组和分子方法的多学科方法来增强我们对 K36M 和 G34 癌组蛋白的理解，并将我们的理解应用于诊断和治疗应用。具体来说，我们将： i) 使用基于细胞的系统和患者肿瘤样本来识别组蛋白突变引起的染色质景观的变化； ii) 描述有助于建立肿瘤发生的失调发育程序的特征。这些研究将为开发旨在改善 NSD1/2 和组蛋白 H3 突变对人类癌症的致病作用的治疗策略提供指导。我们还将扩展我们的研究结果，以阐明 NSD1 和 H3 K36M 突变改变鳞状细胞癌染色质景观的机制（目标 1）。我们将定义 G34 突变改变染色质修饰和基因表达的机制，并且我们将定义 H3.3 伴侣通路在介导 G34 表型中的作用（目标 2）。此外，我们发现 H3K36 甲基化会对抗 PRC2 活性，从而阻止 Polycomb 介导的基因抑制。我们现在将利用这些生化发现来确定 EZH2 H3K36 结合袋在不同肿瘤发生模型中的功能（目标 3）。我们研究的预期结果将引导我们制定新颖的理论，并提供这些癌组蛋白的重要机制见解，这些见解可以在体内癌症模型（项目 1,2）和体外化学平台（项目 3）中轻松进行测试。为了实现这些目标，项目 4 还需要与两个核心进行密切互动。