Reactivation Methylation-Silenced Genes by Polyphenols

通过多酚重新激活甲基化沉默的基因

• 批准号: 6728906
• 负责人: CHUNG S. YANG
• 金额: $ 30.14万
• 依托单位: RUTGERS, THE STATE UNIV OF N.J.
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-05-10 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6728906
• 关键词: CpG islands; DNA methylation; angiogenesis inhibitors; antineoplastics; butyrates; colon neoplasms; dietary supplements; flavonoids; gene induction /repression; genetic transcription; genetically modified animals; laboratory mouse; methyltransferase; microarray technology; molecular oncology; neoplasm /cancer nutrition therapy; neoplastic cell; nutrition aspect of cancer; nutrition related tag; oral pharyngeal neoplasm; polymerase chain reaction; prostate neoplasms; protein structure function; tea; tissue /cell culture

DESCRIPTION (provided by applicant): Hypermethylation of promoter CpG islands is an important mechanism to silence the expression of many tumor suppressors, DNA repair, and other genes in cancer. The long-term goal of this project is to study the inhibition and reversal of this process by dietary polyphenols for the purpose of prevention and treatment of cancer. In preliminary studies, we observed that treatment of human esophageal cancer KYSE 510 cells with the tea polyphenol EGCG caused the reversal of hypermethylation of RARbeta, p16, MGMT, and hMLH1 and the regaining of gene expression. EGCG also inhibited DNMT activity in nuclear extracts. This property of EGCG and related compounds could be explored for cancer chemoprevention and therapy. Our hypothesis is that EGCG and some other dietary polyphenols can inhibit DNMT, prevent or reverse the gene silencing caused by hypermethylation, and contribute to the inhibition of carcinogenesis, In this proposal, we plan to test this hypothesis with the following Specific Aims: 1. To quantify the demethylation and reactivation of hypermethylation-silenced genes (MSGs) such as RARbeta, p16, MGMT, and hMLH1 by EGCG, characterize the pattern of CpG demethylation, and determine the sustainability of the reactivated gene expression. 2. To elucidate the mechanisms by which EGCG inhibits DNMT activity and DNA hypermethylation. The leading hypothesis is that inhibition of DNMT1 by EGCG causes demethylation. Other mechanisms such as those involving AdoMet levels and other methyltransferases, will also be examined. 3. To establish the above observed effects as general phenomena by determining the spectrum of MSGs that are reactivated by EGCG (using methylation microarrays), examining the effects of EGCG on other cell lines (oral, colon, and prostate cancers), and investigating the effects of other dietary polyphenols. 4. To determine the possible synergistic effects in the reactivation of MSGs when EGCG is used in combination with a HDAC inhibitor (butyrate or TSA) or retinoic acid. Possible effects on global hypomethylation will be analyzed. 5. To determine whether EGCG, alone or in combination with other agents, can prevent hypermethylation of genes and tumor development in the intestinal tumorigenesis model in the Min mice.

描述（由申请人提供）： 启动子CpG岛的高甲基化是使许多肿瘤抑制剂，DNA修复和其他基因在癌症中表达表达的重要机制。该项目的长期目标是研究饮食多酚对预防和治疗癌症的抑制和逆转。在初步研究中，我们观察到人类食管癌510细胞用茶多酚EGCG的治疗导致rarbeta，p16，mgmt和hmlh1的高甲基化逆转以及基因表达的重新获得。 EGCG还抑制了核提​​取物中的DNMT活性。可以探索EGCG和相关化合物的这种特性，以进行癌症化学预防和治疗。我们的假设是，EGCG和其他一些饮食中的多酚可以抑制DNMT，预防或逆转由高甲基化引起的基因沉默，并有助于抑制致癌作用，我们计划以以下特定目的检验该假设： 1。通过EGCG量化高甲基化基因（MSG）的脱甲基化和重新激活，例如Rarbeta，P16，MGMT和HMLH1，表征CpG脱甲基化的模式，并确定重新激活基因表达的可持续性。 2。阐明EGCG抑制DNMT活性和DNA高甲基化的机制。主要的假设是通过EGCG抑制DNMT1会导致脱甲基化。还将检查其他机制，例如涉及ADOMET水平和其他甲基转移酶的机制。 3。通过确定由EGCG重新激活的MSG（使用甲基化微阵列）的MSG的光谱，研究EGCG对其他细胞系（口服，结肠癌和前列腺癌）的影响，并研究其他饮食多酚的作用。 4。确定当EGCG与HDAC抑制剂（丁酸酯或TSA）或视黄酸结合使用时，MSG的重新激活中可能产生的协同作用。将分析对全球降压甲基化的可能影响。 5。为了确定EGCG单独还是与其他药物结合可以防止肠道小鼠中肠道肿瘤发生模型中基因和肿瘤发育的过度甲基化。