TOXICANT-INDUCED DEREGULATION OF C-HA-RAS EXPRESSION

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。几项实验和流行病学研究 已经建立了有毒环境或职业之间的联系 化学物质和动脉粥样硬化的形成。苯并(A)芘(BaP)已被证明 在体内和体外诱导SMC增殖， 这一过程代表了动脉粥样硬化形成的标志。BAP也增加了 C-Ha-ras是一种原癌基因，在大约20%的 人肿瘤，在培养的血管平滑肌细胞中。建议的研究是设计的 探讨导致RAS改变的分子机制 表达，这可能有助于建立一个增生性 BaP处理的SMC的表型。介导BaP的DNA序列元件 将使用突变的互补方法来确定响应 分析和瞬时转染法，结合体外DNA- 有约束力的分析。C-Ha-ras诱导的构效关系 将通过使用具有代表性的化学品来定义，这些化学品是 BNP代谢物，诱导氧化应激，和/或是AH的配体 受体。BaP诱导的DNA结合蛋白的分子靶点将是 使用免疫耗竭的体外DNA结合试验进行鉴定 核提取物和重组基本转录因子。澄清 BaP调控c-Ha-ras转录的可能机制 对处理后的SMC的增殖适应有重要意义，AS 对毒物引起的人类动脉粥样硬化也是如此。

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.