TOXICANT-INDUCED DEREGULATION OF C-HA-RAS EXPRESSION

毒物引起的 C-HA-RAS 表达失调

• 批准号: 2414959
• 负责人: CHRISTOPHER M BRAL
• 金额: $ 0.82万
• 依托单位: TEXAS A&M UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-05-01 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/2414959
• 关键词: DNA binding protein; atherosclerosis; benzopyrenes; biological signal transduction; environmental toxicology; gene expression; gene mutation; molecular genetics; nucleic acid sequence; oxidative stress; phenotype; protooncogene; toxicant interaction; transcription factor; transfection; vascular smooth muscle

Atherosclerosis is one of the leading causes of death in developed industrialized nations. Several experimental and epidemiological studies have established a link between toxic environmental or occupational chemicals and atherogenesis. Benzo(a)pyrene (BaP) has been demonstrated to induce smooth muscle cell (SMC) proliferation both in vivo and in vitro, a process which represents a hallmark of atherogenesis. BaP also increases the expression of c-Ha-ras, a protooncogene found in approximately 20% of human tumors, in cultured vascular SMCs. The proposed studies are designed to investigate the molecular mechanisms resulting in altered ras expression, which may contribute to establishment of a proliferative phenotype in BaP-treated SMCs. The DNA sequence elements mediating the BaP response will be identified using a complementary approach of mutational analysis and transient transfection assays, coupled to in vitro DNA- binding assays. Structure-activity relationships for c-Ha-ras induction will be defined through use of representative chemicals which are major BnP metabolites, induce oxidative stress, and/or are ligands of the Ah receptor. Molecular targets of BaP-inducible DNA-binding proteins will be identified using in vitro DNA-binding assays employing immunodepleted nuclear extracts and recombinant basal transcription factors. Elucidation of the mechanisms by which BaP modulates c-Ha-ras transcription may have significant implications for proliferative adaptations of treated SMCs, as well as for toxicant-induced atherosclerosis in humans.

动脉粥样硬化是发达国家死亡的主要原因之一 工业化国家。多项实验和流行病学研究 已在有毒环境或职业之间建立了联系 化学物质和动脉粥样硬化。苯并(a)芘 (BaP) 已被证明可以 在体内和体外诱导平滑肌细胞（SMC）增殖， 代表动脉粥样硬化形成标志的过程。 BaP 也会增加 c-Ha-ras 的表达，这是一种在大约 20% 的细胞中发现的原癌基因 人类肿瘤，在培养的血管 SMC 中。拟议的研究设计 研究导致 ras 改变的分子机制 表达，这可能有助于建立增殖性 BaP 处理的 SMC 中的表型。介导 BaP 的 DNA 序列元件 将使用突变的补充方法来确定反应 分析和瞬时转染测定，结合体外 DNA- 结合测定。 c-Ha-ras 诱导的结构-活性关系 将通过使用主要的代表性化学品来定义 BnP 代谢物，诱导氧化应激，和/或是 Ah 的配体 受体。 BaP 诱导性 DNA 结合蛋白的分子靶标将是 使用免疫耗竭的体外 DNA 结合测定法进行鉴定 核提取物和重组基础转录因子。说明 BaP 调节 c-Ha-ras 转录的机制可能有 对处理过的 SMC 的增殖适应具有重大影响，如 以及有毒物质引起的人类动脉粥样硬化。