GENESIS AND CONSEQUENCES OF ABERRANT DNA METHYLATION

异常 DNA 甲基化的起源和后果

• 批准号: 2882508
• 负责人: Paula M. Vertino
• 金额: $ 19.6万
• 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/2882508
• 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 博士的总体研究计划集中于 了解改变的建立的分子机制 DNA 甲基化模式及其对人类致癌的贡献。 这 正常情况下未甲基化的含 CpG 岛基因的异常甲基化 启动子就是这样一种改变，最近与 灭活人类癌症中的肿瘤抑制基因和其他基因。 在人类 乳腺癌中，CpG岛甲基化参与失活 已知一些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、 和 p16/INK4A 基因。 此外，DNA 表达增加 (胞嘧啶-5)-甲基转移酶（DNA MTase），负责 DNA 的酶 哺乳动物细胞中的甲基化与更具攻击性的细胞有关 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的研究， 很少有研究探讨先前未甲基化的 CpG 岛序列如何 在成体体细胞中从头甲基化，并且该事件是否 在基因沉默中发挥直接作用。 我们最近证明了 被设计成过表达 DNA MTase 的细胞可用于模拟 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。 解决潜在的分子机制 启动子区异常甲基化以及该事件在人类中的作用 乳腺癌发生过程中，我们建议开发 de nov 的体外模型 人乳腺上皮细胞的甲基化。 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 人类乳腺肿瘤中的甲基化。 其次，我们要判断是否 位点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该基因 通过确定DNA MTase驱动的下游效应来沉默过程 CpG 岛甲基化对基因表达的影响。 进一步了解 aberran de novo甲基化的发生和后果 致癌作用将为未来新型药物的开发提供基础 治疗人类乳腺癌和其他癌症的去甲基化策略 肿瘤性疾病。