CARCINOGEN METABOLIZING P450S--REGULATION BY CYTOKINES

产品说明： 细胞因子可作为P450的生理调节剂 水平，影响许多P450亚家族的成员。 其中许多， 包括多环芳烃诱导的P450， 1A 1和P450 1A 2，代谢致癌物质，有助于其 解毒和/或活化。据报道，IL-1和H2 O2 抑制P450 1A 1和P450 1A 2的转录激活， 多环化合物 这种抑制可以通过提高 细胞谷胱甘肽水平细胞因子水平会有很大的变化 在不同的组织和器官中， 个体，由于特定的生理状态或遗传因素 （急性或慢性炎症或感染，吸烟，饮食， 免疫反应性等）。工作假设是， 细胞因子水平或P450基因对 细胞因子可能不同地影响致癌物的表达， 代谢P450，并成为一个重要因素， 基因和/或环境决定的差异， 个体对致癌物的易感性。两个DNA元素 已经报道参与介导IL-1的作用， H2 O2：（i）XRE，介导对芳基反应的元素 烃，和（ii）称为IL-1反应元件的新元件， 恶心。 这种元素结合一种因子，ILRP，它迅速下降- 在用IL-1或H2 O2处理的分离的肝细胞中调节。 这项研究所验证的具体假设是，IL-1 H2 O2依赖性抑制P450 1A 1转录， 通过抑制ILRE与XRE的协同性介导， 由于ILRP结合活性的下调而产生的其它增强子，和 通过抑制XRE之间的协同性。 具体目标是： 1.确定ILRE和XRE介导下调的机制- IL-1和H2 O2对P450 1A 1转录的调节 DNA介导的 基因 转让 表达 载体含有各种 将进行XRE、ILRE和其他增强剂的组合， 确定这些元素如何合作，以调解响应， IL-1和H2 O2。 在离体大鼠肝细胞中。 2. 表征序列 特异性和DNA-蛋白质相互作用对IL-1和H2 O2很重要。 反应性使用体外和体内足迹相关联 用电泳迁移率变动分析野生型和 突变ILRE。 ILRP的组织分布及其调控 ILRP结合 氧化剂、抗氧化剂、生长 因素，胰岛素，钒酸盐和其他因素将使用 电泳迁移率变动分析。3. 克隆 ILRP cDNA使用 表达克隆、噬斑杂交或基于抗体 程序.

DESCRIPTION: Cytokines may act as physiological modulators of P450 levels, influencing members of many P450 subfamilies. Many of these, including the polycyclic aromatic hydrocarbon-inducible P450s, P450 1A1 and P450 1A2, metabolize carcinogens, contributing to their detoxification and/or activation. IL-1 and H2O2 have been reported to inhibit the transcriptional activation of P450 1A1 and P450 1A2 by polycyclic compounds. This inhibition can be blocked by raising cellular glutathione levels. Cytokine levels can vary dramatically within different tissues and organs and also systemically between individuals, due to particular physiological states or genetic factors (acute or chronic inflammation or infection, cigarette smoking, diet, immunoreactivity, etc.). The working hypothesis is that differences in cytokine levels or differences in the responsiveness of P450 genes to cytokines may differentially affect the expression of carcinogen- metabolizing P450s and be an important factor contributing to genetically and/or environmentally determined differences among individuals in their susceptibility to carcinogens. Two DNA elements have been reported to be involved in mediating the effect of IL-1-and H2O2: (i) XREs, the elements that mediate responsiveness to aryl hydrocarbons, and (ii) a novel element termed IL-1 responsive element, ILRE. This element binds a factor, ILRP, that is rapidly down- regulated in isolated hepatocytes treated with either IL-1 or H2O2.. The specific hypothesis being tested by this research is that the IL-1 and H2O2-dependent suppression of P450 1A1 transcription is mediated by suppression of cooperativity of ILREs with XREs and other enhancers due to down regulation of ILRP binding activity, and by suppression of cooperativity between XREs. Specific objectives are: 1. Determine the mechanism by which ILREs and XREs mediate down- regulation of P450 1A1 transcription by IL-1 and H2O2.. DNA-mediated gene transfer of expression vectors containing various combinations of XREs, ILREs and other enhancers will be done to determine how these elements cooperate to mediate responsiveness to IL-1 and H2O2. in isolated rat hepatocytes. 2. Characterize sequence specificity and DNA-protein interactions important for IL-1 and H2O2. responsiveness using in vitro and in vivo footprinting in association with electrophoretic mobility shift analyses with wild type and mutant ILREs. The tissue distribution of the ILRP and the regulation of ILRP binding activity by oxidants, antioxidants, growth factors, insulin, vanadate, and other factors will be determined using electrophoretic mobility shift assays. 3. Clone ILRP cDNA using either expression cloning, plaque hybridization or antibody based procedures.