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: 10024846
• 负责人: Peter W Lewis
• 金额: $ 26.27万
• 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/10024846
• 关键词: Affect; Astrocytoma; Binding; Biochemical; Biochemistry; Biological Assay; Bone neoplasms; Brain Stem Glioma; CRISPR/Cas technology; Cancer Model; Cell Differentiation process; Cell Proliferation; Cells; Chemistry; Chondroblastoma; Chromatin; Clinical; Complex; CpG Islands; DNA Packaging; Development; Diffuse; EZH2 gene; Elements; Enhancers; Ependymoma; Epigenetic Process; Event; Foundations; Frequencies; Gene Expression; Gene Silencing; Genes; Genetic Screening; Giant cell tumor of bone; Glioma; Goals; Health; Histone H3; Histones; Human; In Vitro; Investigation; Kinetics; Malignant - descriptor; Malignant Neoplasms; Mediating; Methylation; Modeling; Molecular; Molecular Target; Mutation; Pathogenesis; Pathway interactions; Phenotype; Polycomb; Positioning Attribute; Post-Translational Protein Processing; Post-Translational Regulation; Posterior Fossa; Proteins; Regulation; Repression; Residual state; Role; Structure-Activity Relationship; Surface; Testing; Therapeutic Intervention; Toxic effect; Transcript; Undifferentiated; Work; base; big gastrin; disease diagnosis; effective therapy; gene repression; genome-wide; genomic locus; in vivo; innovation; insight; member; mutant; novel; prevent; programs; recruit; sarcoma; sensor; theories; 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.

总结：已知的组蛋白H3 K36定向甲基转移酶对于正常动物发育是必需的，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控机制，包括H3 K36甲基化，来驱动肿瘤发生。以前，我们发现H3.3 G34癌组蛋白选择性地阻断SETD 2介导的H3 K36甲基化，并影响导致异常细胞分化和增殖的基因增强子的活性。此外，我们发现H3 K36 M癌组蛋白通过竞争性抑制NSD 1/2和SETD 2酶促进组蛋白和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，以确定H3.3 G34和H3 K36 M癌组蛋白通过H3 K36甲基化的误调节实现促肿瘤基因表达程序的机制。我们将采用多学科的方法，整合生物化学，基因组学和分子方法，以提高我们对K36 M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。具体而言，我们将：i）使用基于细胞的系统和患者肿瘤样品鉴定组蛋白突变引起的染色质景观的变化;和ii）表征帮助建立肿瘤发生的失调的发育程序。这些研究将为开发旨在改善NSD 1/2和组蛋白H3突变在人类癌症中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NSD 1和H3 K36 M突变改变鳞状细胞癌染色质景观的机制（Aim 1）。我们将定义G34突变改变染色质修饰和基因表达的机制，并定义H3.3分子伴侣途径在介导G34表型中的作用（目的2）。此外，我们发现H3 K36甲基化对抗PRC 2活性，从而防止Polycomb介导的基因抑制。我们现在将利用这些生物化学发现来确定EZH 2 H3 K36结合口袋在不同肿瘤发生模型中的功能（目的3）。我们研究的预期结果将引导我们制定新的理论，并提供这些致癌组蛋白的关键机制见解，这些致癌组蛋白可以在体内癌症模型（项目1，2）和体外化学平台（项目3）中进行测试。为了实现这些目标，项目4还需要与两个核心密切互动。