权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Regulation of PRC2 functions by PARP1

PARP1 对 PRC2 功能的调节

基本信息

批准号：
9752614
负责人：
Italo Tempera
金额：
$ 33.29万
依托单位：
TEMPLE UNIV OF THE COMMONWEALTH
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-08-01 至 2020-04-29
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9752614
关键词：
Affinity Binding Biological Assay Cancer Patient Catalytic Domain Cell Death Cell Line Cell physiology Cells Chromatin Chromatin Structure Clinical Trials Complex DNA Repair Data Deposition Drug effect disorder EZH2 gene Epigenetic Process FDA approved Gene Expression Gene Silencing Genes Genome Heterochromatin Histone H3 Histones Immunoprecipitation Impairment In Vitro Kinetics Lysine Malignant Neoplasms Maps Mediating Methylation Modification Mutation PARP inhibition Pharmaceutical Preparations Play Poly(ADP-ribose) Polymerases Polycomb Process Proteins Regulation Reporting Resistance Role Site Stress System Testing Therapeutic Time Work base cancer cell cancer clinical trial chromatin immunoprecipitation chromatin modification epigenetic drug gene repression genome sequencing genome-wide improved inhibitor/antagonist insight member mutant novel prevent response transcriptome

项目摘要

Project summary Poly (ADP-ribose) polymerase —PARP— activity plays a necessary role in DNA repair and inhibitors of PARP1 have been widely used to target cancers with impaired DNA repair machinery. In the past few years however PARP1 has also emerged as an important factor in regulating gene expression through chromatin. Targeting epigenetics is a promising approach in cancer as many drugs exist to alter epigenetic modifications. For PARP inhibitors, their application however as epigenetic drugs requires a more complete understanding of the precise function of PARP1 and its mechanism of action in regulating chromatin structure. We previously discovered that inhibition of PARP1 activity dramatically changes the expression levels of hundreds of genes, including genes involved in cancer. We found that increased levels of the Polycomb Repressive Complex 2 catalytic subunit EZH2 are responsible for some effects caused by PARP inhibition. Here we reported for the first time that (1) PARP1 and EZH2 occupancy negatively correlate across the genome; (2) PARP1 can directly modify EZH2; and (3) PARylation alters the enzymatic activity of EZH2. Based on these data we hypothesize that PARP1 and PARylation play an important and underappreciated role in EZH2 activity, and inhibitors of PARP can alter PRC2-mediated gene repression. Our findings may have significant translational implications since aberrant EZH2 activity contributes to cancer and PARP1 inhibitors are in clinical trials; however, their effects and interactions have not been explored at the functional and mechanistic levels. Here we propose to establish PARP1 and PARylation as a novel mechanism of EZH2 regulation and to determine the mechanisms and the functional relevance of PARP- mediated EZH2 inhibition. To test our hypothesis we propose : (Aim 1) To define mechanisms of PARP1 binding and PARylation in antagonizing EZH2-mediated chromatin modification we will assess EZH2 binding and H3K27me3 deposition across the genome after changes in PARP activity; (Aim 2) To establish mechanisms by which PARylation inhibits EZH2 functions we will determine the effect of PARylation on EZH2 affinity for histone and for other PRC2 proteins; (Aim 3) To evaluate the relevance of EZH2 PARylation we will characterize the effect of PAR-resistant EZH2 mutant on chromatin composition and PRC2 functions. We hypothesize that PARylation of EZH2 removes EZH2 from chromatin and that preventing PARylation results in persistent EZH2 binding and gene repression. The impact of this work extend beyond the effect of PARP1 and heterochromatin formation to provide a better insight into the global role of PARP1 in chromatin regulation. By characterizing the mechanism and the relevance of PARP1 activity on EZH2 functions we will provide a better rationale for targeting PARP1 as a treatment in cancer. In the long run, this work has the potential to improve the therapeutic application of PARP1 inhibitors for treating cancer and to identify cancer patients who can benefit by these class of drugs.

项目摘要聚（ADP-核糖）聚合酶-PARP-活性在DNA修复中起着必要的作用， PARP 1已被广泛用于靶向DNA修复机制受损的癌症。过去几年然而，PARP 1也已成为通过染色质调节基因表达的重要因子。靶向表观遗传学是治疗癌症的一种有前途的方法，因为存在许多药物来改变表观遗传修饰。然而，对于PARP抑制剂，它们作为表观遗传药物的应用需要更全面地了解PARP抑制剂的作用。 PARP 1的精确功能及其在调节染色质结构中的作用机制。我们以前发现，抑制PARP 1活性会显著改变细胞内数百个基因，包括与癌症有关的基因。我们发现Polycomb的含量增加抑制复合物2催化亚基EZH 2负责PARP抑制引起的一些效应。在这里，我们首次报道了（1）PARP 1和EZH 2的占有率在整个细胞中呈负相关。（2）PARP 1可以直接修饰EZH 2;（3）PAR化改变EZH 2的酶活性。基于这些数据，我们假设PARP 1和PARylation发挥了重要而未被重视的作用， PARP抑制剂可以改变PRC 2介导的基因阻遏。我们的发现可能具有重要的翻译意义，因为异常的EZH 2活性有助于癌症和PARP 1抑制剂正在临床试验中;然而，它们的作用和相互作用还没有被证实。在功能和机制层面进行了探索。在这里，我们建议建立PARP 1和PAR化作为一个 EZH 2调节的新机制，并确定PARP的机制和功能相关性。介导的EZH 2抑制。为了验证我们的假设，我们提出：（目的1）确定PARP 1结合和PAR化的机制，拮抗EZH 2介导的染色质修饰，我们将评估EZH 2结合和H3 K27 me 3 PARP活性变化后在基因组中的沉积;（目的2）建立机制，我们将确定PAR化对EZH 2与组蛋白亲和力的影响（目的3）为了评估EZH 2 PAR化的相关性，我们将表征 PAR抗性EZH 2突变体对染色质组成和PRC 2功能的影响。我们假设EZH 2的PAR化从染色质中去除EZH 2，并且阻止PAR化导致持续的EZH 2结合和基因阻遏。这项工作的影响超出了PARP 1和异染色质形成的影响，更好地了解PARP 1在染色质调节中的整体作用。通过描述机制和 PARP 1活性与EZH 2功能的相关性，我们将为靶向PARP 1作为EZH 2功能的靶点提供更好的理论基础。治疗癌症。从长远来看，这项工作有可能提高治疗应用的用于治疗癌症的PARP 1抑制剂，并鉴定可以通过这些类别的药物获益的癌症患者。