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的重点是 了解改变的分子机制 DNA甲基化模式及其对人类致癌作用的贡献。 这 通常未甲基化CpG岛的基因的ABERRAN甲基化 发起人是最近与 灭活的tumo抑制剂和人类癌症中的其他基因。 在人类中 乳腺癌，CpG岛甲基化涉及 几个基因已知是肿瘤细胞生长和 临床结局，包括雌激素受体基因，电子钙粘蛋白基因， 和p16/ink4a基因。 此外，DNA的表达增加 （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侵略性有关 雌激素受体负肿瘤表型，尽管有很多 研究将异常CpG岛甲基化与基因无活跃相关的研究， 很少有研究解决以前未甲基化的CpG岛序列 在成年体细胞中成为从头开始的甲基化de de de 在基因沉默中起着直接的作用。 我们最近证明了 设计用于过表达DNA MTase的细胞可用于建模 CpG岛甲基化的进展可能在早期发生 肿瘤发生的阶段。 解决分子机制 异常启动子区域甲基化和该事件在人类中的作用 乳腺癌发生，我们建议开发一个de Nov的体外模型 人乳房上皮细胞中的甲基化。 具体来说，我们会的 确定DNA MTase的表达增加是否可以驱动 已知与CPG岛相关的已知基因的甲基化 人类breas肿瘤中的甲基化。 其次，我们将确定是否 基因座特异性信号用于指导CpG岛的从头甲基化 乳房上皮细胞中的启动子。 最后，我们将确定是否de CpG岛序列的Novo甲基化足以启动基因 通过确定DNA MTase驱动的下游效应来沉默过程 CpG岛甲基化基因表达。 进一步理解 阿伯兰·德甲基化的起源和后果 致癌作用将为新颖的未来发展提供基础 治疗人类乳腺癌和其他治疗的脱甲基化策略 肿瘤疾病。