Molecular basis for aberrant de novo DNA methylation in cancer

癌症中异常 DNA 从头甲基化的分子基础

基本信息

批准号：
10565916
负责人：
Karim Jean Armache
金额：
$ 52.18万
依托单位：
NEW YORK UNIVERSITY SCHOOL OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-02-07 至 2027-01-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10565916
关键词：
Ablation Binding Biochemistry Cancer Biology Cell Differentiation process Cells Cellular Assay Chromatin Complex CpG Islands CpG dinucleotide Cryoelectron Microscopy Cytosine DNA DNA Methylation DNA Modification Methylases DNMT3B gene DNMT3a DNMT3a mutation Development Enzymes Epigenetic Process Equilibrium FDA approved Family Foundations Frequencies Gene Expression Regulation Genes Genetic Genomics Histones Human Hypermethylation Impairment Individual Intercistronic Region Length Malignant Neoplasms Mediating Meta-Analysis Methylation Methyltransferase Missense Mutation Modeling Molecular Molecular Conformation Monoubiquitination Mus Mutate Mutation N-terminal Neoplastic Cell Transformation Normal tissue morphology Nucleosomes Oncogenic Organoids PRC1 Protein Patients Pattern Play Polycomb Post-Translational Protein Processing Protein Isoforms Publishing RNA Splicing Recurrence Regulation Role Sampling Site Structure Testing Therapeutic Therapeutic Index Tissue Differentiation Tissues Toxic effect Tumor Suppressor Genes Variant Work cancer cell cancer initiation chromatin modification design epigenomics genome-wide histone modification human disease inhibitor insight interdisciplinary approach member novel promoter recruit stem cells tumor tumorigenesis

项目摘要

PROJECT SUMMARY Methylation of cytosine in the context of CpG dinucleotides is an essential and highly conserved chromatin modification. It plays a critical role in gene regulation, cell differentiation and organismal development. Aberrant patterns of DNA methylation are commonly observed in human diseases including cancer. CpG islands (CGIs), regions with a high frequency of CpG sites found at the promoters of ~40% mammalian genes, are devoid of DNA methylation in normal tissues but become hypermethylated in tumors, leading to the silencing of many tumor suppressor genes. However, the molecular mechanisms underlying CGI hypermethylation in cancer remain poorly understood, and therefore therapeutic strategies that specifically target CGI hypermethylation are lacking. DNA methylation is established by the DNMT3 family of de novo DNA methyltransferases. The DNMT3 family includes two catalytically active members, DNMT3A and DNMT3B. DNMT3A has two splice variants DNMT3A1 and DNMT3A2. While DNMT3A2 and DNMT3B are expressed during early development, DNMT3A1 is the main de novo DNA methyltransferase expressed in differentiated tissues. We and others have previously demonstrated that DNMT3A1 contains regulatory domains interacting with histone post-translational modifications (PTMs) to guide its genomic targeting to regions marked by H3K36 di- and tri-methylation (H3K36me2/3). Our collaborative preliminary studies have identified an additional functional domain unique to DNMT3A1 that facilitates its interaction with histone H2AK119 mono-ubiquitination (H2AK119Ub), a PTM catalyzed by Polycomb Repressive Complex 1 (PRC1). These findings resonate with meta-analyses of patient tumor samples, which revealed a strong correlation between CGIs that gain methylation in cancers and those regulated by Polycomb complexes in normal tissues. We will pursue a hypothesis that the redistribution of DNMT3A1 from H3K36 methylation to H2AK119ub-marked CGIs drives CGI hypermethylation and neoplastic transformation. To test this hypothesis, we will employ a multidisciplinary approach that leverages the complementary expertise of Armache and Lu labs, spanning from chromatin biochemistry, structural study to cancer biology and epigenomics. These studies will reveal the molecular mechanisms of DNMT3A1 regulation by H3K36 methylation and H2AK119Ub and uncover how the balance between these PTMs mediates the recruitment, activity and function of DNMT3A1 in healthy tissues and tumors. Expected results will provide an enhanced understanding of the dynamics, cause and consequence of CGI hypermethylation – a molecular hallmark of human cancers that remains a key focus of the field. Furthermore, they will lay the foundation for developing inhibitors that target the interaction of DNMT3A1 with H2AK119Ub to specifically reverse cancer- associated CGI hypermethylation, which are expected to show less toxicity compared to current FDA-approved unspecific DNA hypomethylating agents.

项目概要 CpG 二核苷酸背景下胞嘧啶的甲基化是一种必需且高度保守的染色质它在基因调控、细胞分化和生物体发育中起着关键作用。 DNA 甲基化模式在包括癌症在内的人类疾病中很常见。在约 40% 哺乳动物基因的启动子处发现的 CpG 位点频率较高的区域缺乏 DNA在正常组织中甲基化，但在肿瘤中变得高度甲基化，导致许多基因沉默然而，癌症中 CGI 高甲基化的分子机制。仍然知之甚少，因此专门针对 CGI 高甲基化的治疗策略是 DNA 甲基化是由 DNMT3 家族的从头 DNA 甲基转移酶建立的。该家族包括两个催化活性成员，DNMT3A 和 DNMT3B 有两个剪接变体。 DNMT3A1 和 DNMT3A2 在早期发育过程中表达，而 DNMT3A2 和 DNMT3B 在早期发育过程中表达。是我们和其他人之前在分化组织中表达的主要 DNA 甲基转移酶。 DNMT3A1 包含组蛋白翻译后证明的调节域修饰 (PTM) 以指导其基因组靶向 H3K36 二甲基化和三甲基化标记的区域 (H3K36me2/3)。我们的合作初步研究已经确定了一个独特的附加功能域。 DNMT3A1 促进其与组蛋白 H2AK119 单泛素化 (H2AK119Ub)（一种 PTM）相互作用由 Polycomb 抑制复合物 1 (PRC1) 催化，这些发现与患者的荟萃分析产生共鸣。肿瘤样本，揭示了在癌症中获得甲基化的 CGI 与那些在癌症中获得甲基化的 CGI 之间存在很强的相关性。我们将提出一个假设，即正常组织中的 Polycomb 复合物的重新分布。 DNMT3A1从H3K36甲基化到H2AK119ub标记的CGI驱动CGI高甲基化和肿瘤为了检验这一假设，我们将采用一种利用多学科方法。 Armache 和 Lu 实验室的专业知识互补，涵盖从染色质生物化学、结构研究到这些研究将揭示 DNMT3A1 调控的分子机制。 H3K36 甲基化和 H2AK119Ub 并揭示这些 PTM 之间的平衡如何介导 DNMT3A1 在健康组织和肿瘤中的招募、活性和功能的预期结果将提供一个结果。增强对 CGI 高甲基化的动力学、原因和后果的理解——一种分子机制人类癌症的标志仍然是该领域的重点关注点，此外，它们还将奠定基础。开发针对 DNMT3A1 与 H2AK119Ub 相互作用的抑制剂，以特异性逆转癌症 - 相关的 CGI 高甲基化，与目前 FDA 批准的相比，预计其毒性较小非特异性 DNA 低甲基化剂。