GENESIS AND CONSEQUENCES OF ABERRANT DNA METHYLATION

异常 DNA 甲基化的起源和后果

• 批准号: 6164264
• 负责人: Paula M. Vertino
• 金额: $ 20.19万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-05-01 至 2003-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6164264
• 关键词: CpG islands; DNA directed DNA polymerase; DNA methylation; cadherins; cell growth regulation; complementary DNA; enzyme activity; estrogen receptors; gene induction /repression; human genetic material tag; mammary epithelium; oncogenes; tissue /cell culture

DESCRIPTION: Dr. Vertino's overall research initiative is focused on understanding the molecular mechanisms underlying establishment of altered DNA methylation patterns and its contribution to human carcinogenesis. The aberran methylation of normally unmethylated CpG island-containing gene promoters is one such alteration that has recently been implicated in the inactivation tumo suppresser and other genes in human cancer. In human breast cancer, CpG island methylation is involved in the inactivation of several genes known to be important mediators of tumor cell growth and clinical outcome, including the estrogen receptor gene, the E-cadherin gene, and the p16/INK4A gene. Furthermore, increased expression of DNA (cytosine-5)-methyltransferase (DNA MTase), the enzyme responsible for DNA methylation in mammalian cells, is associated with the more aggressive estrogen receptor negative tumor phenotype Although there have been numerous studies correlating aberrant CpG island methylation with gene inactivity, few studies have addressed how previously unmethylated CpG island sequences become methylated de novo in adult somatic cells and whether this event plays a direct role in gene silencing. We have recently demonstrated that cells engineered to overexpress DNA MTase can be used to model the progression of CpG island methylation as it might occur during the early stages of tumorigenesis. To address the molecular mechanisms underlying aberrant promoter region methylation and the role of this event in human breast carcinogenesis, we propose to develop an in vitro model of de nov methylation in human breast epithelial cells. Specifically, we will determine whether increased expression of DNA MTase can drive the methylation of genes known to be silenced in association with CpG island methylation in human breas tumors. Secondly, we will determine whether locus-specific signals serve to direct the de novo methylation of CpG island promoters in breast epithelial cells. Lastly, we will determine whether de novo methylation of CpG island sequences is sufficient to initiate the gene silencing process by determining the downstream effects of DNA MTase-driven CpG island methylation on gene expression. A further understanding of the genesis and consequences of aberran de novo methylation during carcinogenesis will provide the basis for the futur development of novel demethylation strategies in the treatment of human breast cancer and other neoplastic diseases.

描述：Vertino博士的整体研究计划集中在 了解改变的建立的分子机制 DNA甲基化模式及其在人类肿瘤发生中的作用 的 正常非甲基化CpG岛基因的异常甲基化 启动子是一个这样的改变，最近已经牵连在 失活肿瘤抑制基因和其他基因。 人 在乳腺癌中，CpG岛甲基化参与了 已知几种基因是肿瘤细胞生长的重要介质， 临床结果，包括雌激素受体基因，E-钙粘蛋白基因， p16/INK 4A基因。 此外，DNA表达增加 （胞嘧啶-5）-甲基转移酶（DNA MTase），负责DNA 哺乳动物细胞中的甲基化，与更具侵略性的 雌激素受体阴性肿瘤表型 将异常CpG岛甲基化与基因失活相关联的研究， 一些研究已经阐明了先前未甲基化的CpG岛序列 在成年体细胞中重新甲基化， 在基因沉默中起着直接的作用。 我们最近已经证明， 可使用经工程改造以过表达DNA MTase的细胞来模拟 CpG岛甲基化的进展，因为它可能发生在早期 肿瘤发生的阶段。 为了解决潜在的分子机制， 异常启动子区甲基化及其在人类中的作用 乳腺癌发生，我们建议建立一个体外模型的de nov 在人类乳腺上皮细胞中的甲基化。 具体来说，我们将 确定DNA MTase表达的增加是否可以驱动 已知与CpG岛相关的沉默基因的甲基化 甲基化在人乳腺肿瘤中的作用。 其次，我们将确定 基因座特异性信号用于指导CpG岛的从头甲基化 乳腺上皮细胞中的启动子。 最后，我们将确定是否 CpG岛序列的新甲基化足以启动基因 通过确定DNA MTase驱动的下游效应的沉默过程 CpG岛甲基化对基因表达的影响。 进一步理解本 异常从头甲基化的发生和后果 为今后开发新的抗肿瘤药物提供了依据。 去甲基化策略在治疗人类乳腺癌和其他癌症中的应用 肿瘤性疾病