Mechanisms of De Novo Methylation in Cancer

癌症中从头甲基化的机制

基本信息

批准号：
8060542
负责人：
PETER A JONES
金额：
$ 44.13万
依托单位：
UNIVERSITY OF SOUTHERN CALIFORNIA
依托单位国家：
美国
项目类别：
财政年份：
1999
资助国家：
美国
起止时间：
1999-09-17 至 2014-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8060542
关键词：
Aberrant DNA Methylation Achievement Address Azacitidine Biochemical Cells Chromatin Colon Carcinoma Complex CpG Islands Custom Cytosine DNA DNA Methylation DNA Methyltransferase DNA Modification Methylases Deamination Deoxycytidine Development Drug Delivery Systems Drug Design Enzymes Epigenetic Process FDA approved Funding Gene Silencing Genes Goals Grant HCT116 Cells Health Histone Deacetylase Inhibitor Histone H3 Histones Human Human Development Hydrolysis Inherited Maintenance Malignant Neoplasms Malignant neoplasm of prostate Maps Methylation Methyltransferase Myelogenous Normal Cell Nucleosomes Patients Pattern Pharmaceutical Preparations Play Polycomb Positioning Attribute Process Relative (related person)Research Role Somatic Cell Syndrome Testing Transcription Initiation Site Tumor Suppressor Genes Universities cancer cell cancer therapy cell transformation chromatin protein density design epigenomics follow-up histone modification inhibitor/antagonist knock-down malignant phenotype prevent research study restoration

项目摘要

DESCRIPTION (provided by applicant): The objectives of this grant, which has been funded for almost 30 years, have been to understand the mechanisms for the establishment and inheritance of DNA methylation patterns and to develop drugs which can interfere with cytosine methylation and reactivate silenced genes. This research has led to the recent approval by the FDA of two DNA demethylating agents (5-aza-CR and 5-aza-CdR) for the treatment of myeloid dysplastic syndrome. In the next five year period of the project, we hope to take advantage of epigenomic analysis to understand how DNA methylation patterns are established and maintained by an interaction between DNA methyltransferases and specific chromatin components. To do this, we have developed a custom NimbleGen array allowing for the analyses of nucleosomes, histone modifications and DNA methylation in an integrated way at 1,800 transcription start sites (TSS) in normal and transformed cells. In Specific Aim 1, we will utilize the tiling array to map nucleosomes in both normal (PrECs) and transformed prostate cancer cells (PC3). We shall then determine how interfering with DNA methylation pharmacologically in PC3 cells or genetically in HCT116 colon cancer cells alters the distribution of histone marks focusing on the histone H3-K27me3 mark applied by the polycomb repressive complex 2 (PRC2). In Specific Aim 2, we shall determine how the epigenome is reorganized during the restoration of DNA methylation to HCT116 derivatives (DKO) in which two of the three DNA methyltransferases (DNMT1 and DNMT3B) have been genetically knocked down. In Specific Aim 3, we will follow-up on our new results which show the strong anchoring of the de novo methyltransferases DNMT3A and 3B to nucleosomes. We wish to determine how the enzymes interact with nucleosomes so that we can understand how specific patterns are established. In Specific Aim 4, we will continue our quest to develop DNA demethylating drugs which are more stable than those currently approved by the FDA for cancer treatment and which are able to reverse aberrant DNA methylation, histone modifications and nucleosome positioning. Achievement of these aims should have major impact in our understanding of the epigenetics of cancer and have direct relevance to new strategies to treat and prevent cancer. PUBLIC HEALTH RELEVANCE: It has become clear over the last few years that the abnormal silencing of genes by somatically heritable epigenetic processes, can contribute directly to the formation of human cancers. Although we know that altered patterns of DNA methylation play a fundamental role in the silencing of tumor suppressor genes, we do not know how these altered patterns are set up or how normal patterns are established and inherited during human development. Recent excitement in the field has focused on the potential role of gene silencing mechanisms involving the polycomb repressive complexes (PRCs), which are essential for normal development and have recently been found also to play a role in inactivating tumor suppressor genes. These PRCs can directly silence genes by themselves and also somehow set up genes for more permanent silencing induced by DNA methylation. Recently, the FDA has approved two DNA demethylating agents and one histone deacetylase inhibitor for the treatment of particular kinds of cancer.

描述（由申请人提供）：这项资助已资助了近 30 年，其目的是了解 DNA 甲基化模式的建立和遗传机制，并开发可以干扰胞嘧啶甲基化并重新激活沉默的药物。基因。这项研究导致 FDA 最近批准了两种 DNA 去甲基化药物（5-aza-CR 和 5-aza-CdR）用于治疗骨髓增生异常综合征。在该项目的下一个五年期间，我们希望利用表观基因组分析来了解DNA甲基化模式是如何通过DNA甲基转移酶和特定染色质成分之间的相互作用来建立和维持的。为此，我们开发了一种定制 NimbleGen 阵列，可以在正常细胞和转化细胞的 1,800 个转录起始位点 (TSS) 上以集成方式分析核小体、组蛋白修饰和 DNA 甲基化。在具体目标 1 中，我们将利用平铺阵列绘制正常 (PrEC) 和转化前列腺癌细胞 (PC3) 中的核小体图谱。然后，我们将确定在 PC3 细胞中从药理学上或在 HCT116 结肠癌细胞中从遗传学上干扰 DNA 甲基化如何改变组蛋白标记的分布，重点是多梳抑制复合物 2 (PRC2) 应用的组蛋白 H3-K27me3 标记。在具体目标 2 中，我们将确定在 HCT116 衍生物 (DKO) DNA 甲基化恢复过程中表观基因组如何重组，其中三种 DNA 甲基转移酶中的两种（DNMT1 和 DNMT3B）已被基因敲除。在具体目标 3 中，我们将跟进我们的新结果，这些结果显示从头甲基转移酶 DNMT3A 和 3B 与核小体的牢固锚定。我们希望确定酶如何与核小体相互作用，以便我们能够了解特定模式是如何建立的。在具体目标 4 中，我们将继续寻求开发 DNA 去甲基化药物，这些药物比目前 FDA 批准用于癌症治疗的药物更稳定，并且能够逆转异常的 DNA 甲基化、组蛋白修饰和核小体定位。这些目标的实现将对我们对癌症表观遗传学的理解产生重大影响，并与治疗和预防癌症的新策略直接相关。公共健康相关性：过去几年已经清楚地表明，体细胞遗传表观遗传过程导致的基因异常沉默可能直接导致人类癌症的形成。尽管我们知道 DNA 甲基化模式的改变在肿瘤抑制基因的沉默中发挥着重要作用，但我们不知道这些改变的模式是如何建立的，也不知道人类发育过程中正常模式是如何建立和遗传的。该领域最近的兴奋点集中在涉及多梳抑制复合物（PRC）的基因沉默机制的潜在作用上，该复合物对于正常发育至关重要，并且最近发现在灭活肿瘤抑制基因方面也发挥着作用。这些 PRC 本身可以直接沉默基因，也可以以某种方式设置基因，以实现由 DNA 甲基化诱导的更永久的沉默。最近，FDA 批准了两种 DNA 去甲基化药物和一种组蛋白脱乙酰酶抑制剂用于治疗特定类型的癌症。