Project 2: Elucidating Mechanisms of Chromatin Dysregulation by Oncohistones

项目 2：阐明肿瘤组蛋白染色质失调的机制

• 批准号: 10269905
• 负责人: CHARLES DAVID ALLIS
• 金额: $ 26.7万
• 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/10269905
• 关键词: ATAC-seq; Affect; Alleles; Allografting; Animal Model; Bar Codes; Biological Assay; Biology; Cancer Biology; Cancer cell line; Cell Differentiation process; Cell Fate Control; Cell Line; Cell physiology; Cells; Cellular Structures; ChIP-seq; Characteristics; Charge; Chemicals; Childhood Glioma; Chondroblastoma; Chromatin; Chromatin Structure; Collaborations; Complementary DNA; Cues; DNA; DNA Damage; DNA Modification Process; DNA Repair; DNA methylation profiling; Data; Defect; Development; Epigenetic Process; Frequencies; Gene Expression; Genetic; Genetic Screening; Genetic Transcription; Genome; Goals; Grant; Growth; H3 K27M mutation; Histone H3; Histones; Human; Knock-in; Laboratories; Lead; Libraries; Light; Link; Lysine; Malignant Childhood Neoplasm; Malignant Neoplasms; Mass Spectrum Analysis; Mediating; Mesenchymal Stem Cells; Methionine; Missense Mutation; Modeling; Modification; Molecular; Mus; Mutate; Mutation; N-terminal; Nucleosomes; Oncogenic; Pathologic; Pathway interactions; Patients; Pharmacology; Phenotype; Play; Positioning Attribute; Post-Translational Protein Processing; Pre-Clinical Model; Process; Property; Proteins; Reader; Recurrence; Research; Research Personnel; Role; Site; Somatic Mutation; Structure; Tail; Technology; Testing; Therapeutic; Translating; Transplantation; Tumor Subtype; Undifferentiated; Variant; Work; Writing; Xenograft procedure; cancer cell; cancer type; cell type; cellular transduction; design; driver mutation; epigenome; gain of function; genome-wide; histone methyltransferase; histone modification; in vivo; insight; interdisciplinary approach; mouse model; multidisciplinary; novel; oncohistone; prevent; programs; response; sarcoma; self-renewal; small molecule; small molecule inhibitor; success; transcriptome sequencing; transcriptomics; translational approach; tumor; tumorigenesis; tumorigenic

PROJECT SUMMARY (ALLIS) Genome-wide sequencing technologies have allowed an unprecedented discovery of somatic mutations in chromatin and epigenetic modifiers in human cancers, providing mechanistic links between cancer epigenomes and genetic alterations. The collective number of oncogenic mutations in epigenetic regulators has led to the emerging view of “driver mutations” underlying cancer epigenomes. Nowhere is this better illustrated than with the now classical findings of high-frequency (50-95%) missense mutations in core histones, such as histone H3 lysine 27 to methionine (H3K27M) mutation in pediatric gliomas, and H3 lysine 36 to methionine (H3K36M) mutations in chondroblastomas and undifferentiated sarcomas. During the prior grant period, we have shown that these mutations directly prevent the ‘writing’ of some critical regulatory histone post-translational modifications (PTMs) to promote oncogenesis through altered chromatin organization, transcription, and in some cases cell fate and differentiation. More recently, we have extended our understanding of the landscape of histone mutations in cancers. We characterized an unexpectedly broad landscape of novel oncohistone mutations that occur in roughly 4% of all cancers. These mutations are found not only in the H3 N-terminal tail, which is the site of classical oncohistones, but also in the globular domain and in all four core histones. Our preliminary data suggest that a least a subset of these mutations affect one or more properties of chromatin and chromatin-dependent processes including nucleosome stability, histone PTMs, and cellular differentiation. We therefore hypothesize that novel oncohistone mutations will impact the landscape of histone PTMs and chromatin organization in a context dependent manner, leading to dysregulation of gene expression and effects on cell fate and tumorigenesis. The goal of this work is to rigorously test these hypotheses for a comprehensive set of cancer-associated histone mutations using a multidisciplinary approach that include genetics (barcoded oncohistone libraries, mouse models, barcoded-cell lines), epigenetics (ChIP-seq, ATAC-seq, DNA-methylation profiling), transcriptomics (RNA-seq), and chemical biology (“designer chromatin”, small molecule inhibitors). Specifically, we will 1) define molecular mechanisms by which novel oncohistones act and their impact on chromatin and gene expression; 2) determine how these molecular changes translate into phenotypes using cellular differentiation and tumor allograft models, and explore pharmacologic strategies to rescue differentiation blockade; and 3) extend our studies into animal models and diverse cellular contexts to test the roles of novel oncohistones in tumorigenesis and development. Together, these approaches will shed light on the function of newly discovered oncohistones and provide important insight into the role of histones and chromatin structure in tumorigenesis. Our findings are expected to pave new avenues towards intervening pharmacologically the aberrant epigenetic pathways for cancer therapeutics. To facilitate the success of this proposal, a world-class team of investigators, experts in cancer, chromatin and chemical biology, have been assembled.

项目总结（ALLIS） 全基因组测序技术已经允许前所未有地发现体细胞突变， 人类癌症中的染色质和表观遗传修饰剂，提供癌症表观基因组之间的机制联系 和基因改变。表观遗传调节因子中致癌突变的集体数量导致了 癌症表观基因组背后的“驱动突变”的新观点。没有什么地方比这更能说明问题了， 核心组蛋白（如组蛋白H3）中高频率（50-95%）错义突变的经典发现 小儿神经胶质瘤中赖氨酸27突变为甲硫氨酸（H3 K27 M），以及H3赖氨酸36突变为甲硫氨酸（H3 K36 M） 软骨母细胞瘤和未分化肉瘤中的突变。在上一个赠款期间，我们已经表明， 这些突变直接阻止了一些关键的调节性组蛋白的翻译后“书写”， 通过改变染色质组织，转录，以及在某些情况下， 例细胞命运和分化。最近，我们已经扩大了我们对景观的理解， 癌症中的组蛋白突变。我们描述了一个意想不到的广泛景观的新癌组蛋白 突变发生在大约4%的癌症中。这些突变不仅存在于H3 N-末端尾部， 其是经典癌组蛋白的位点，但也在球状结构域和所有四种核心组蛋白中。我们 初步数据表明，这些突变的至少一个子集影响染色质的一种或多种性质， 染色质依赖性过程包括核小体稳定性、组蛋白PTM和细胞分化。我们 因此，假设新的癌组蛋白突变将影响组蛋白PTM和染色质的景观 以依赖于环境的方式组织，导致基因表达失调和对细胞命运的影响 和肿瘤发生。这项工作的目标是严格测试这些假设的一套全面的 癌症相关的组蛋白突变使用多学科的方法，包括遗传学（条形码 癌组蛋白文库、小鼠模型、条形码化细胞系）、表观遗传学（ChIP-seq、ATAC-seq、DNA甲基化 分析）、转录组学（RNA-seq）和化学生物学（“设计者染色质”、小分子抑制剂）。 具体来说，我们将1）定义新的癌组蛋白作用的分子机制及其对 染色质和基因表达; 2）确定这些分子变化如何转化为表型， 细胞分化和肿瘤同种异体移植模型，并探索挽救分化的药理学策略 阻断; 3）将我们的研究扩展到动物模型和不同的细胞环境中，以测试新的 癌组蛋白在肿瘤发生和发展中的作用总之，这些方法将阐明 新发现的癌组蛋白，并提供了重要的洞察组蛋白和染色质结构的作用， 肿瘤发生我们的研究结果有望为干预糖尿病铺平新的道路。 异常表观遗传途径的癌症治疗。为了使这一建议取得成功，世界一流的 一个由癌症、染色质和化学生物学专家组成的调查小组已经成立。