ROLE OF CYTOCHROMES P-450 GENES IN MUTAGENESIS AND CARCINOGENESIS

细胞色素 P-450 基因在突变和癌变中的作用

• 批准号: 3916904
• 负责人: N BATTULA
• 金额: --
• 依托单位: DIVISION OF CANCER EPIDEMIOLOGY AND GENETICS
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3916904
• 关键词: DNA; Retroviridae; carbopolycyclic compound; chemical addition; chemical carcinogen; chemical carcinogenesis; cyclic amine; cytochrome P450; drug carcinogenesis; enzyme biosynthesis; enzyme substrate complex; gene expression; genetic manipulation; human tissue; laboratory mouse; mutagens; nucleic acid sequence; nutrition related neoplasm /cancer; nutrition related tag; toxin metabolism; vaccinia virus

The cytochrome P-450 supergene family codes for enzymes which metabolize a wide array of both xenobiotics including drugs and carcinogens, and endobiotics such as steroids and prostaglandins. In animals, multiple forms of these enzymes exhibiting broad and overlapping substrate specificities are expressed simultaneously, either constitutively or after administration of inducers. To define the contribution of a given cytochrome P-450 to the metabolism of specific drugs and carcinogens, it is important to express these enzymes individually in cells which lack endogenous background for these enzymes. Toward this goal we have begun to develop expression systems in which an individual cytochrome P-450 protein is synthesized from their coding DNA sequences. Success in this effort will enable us to define the contribution of each of these enzymes to mutagenesis and to cell transformation by chemical carcinogens. For this purpose, we have constructed infectious recombinant vaccinia virus and infectious recombinant retrovirus containing the full length coding cDNA sequences for mouse cytochrome P1-450 and P3-450. Human and mouse cells infected with the recombinant viruses expressed high levels of the authentic size proteins that were enzymatically active and displayed substrate specificities diagnostic of the respective enzymes. Preliminary experiments indicate that cytochrome P3-450 selectively activates heterocyclic arylamines and cytochrome P1-450 preferentially activates aromatic hydrocarbons; and this property appears to be mutually exclusive at limiting substrate concentrations. Furthermore, the cytochrome P3-450-activated food mutagens formed specific adducts with the DNA of cells expressing the P3-450. The DNA adducts detected were identical to those formed in mouse or rat liver after the in vivo administration of the food mutagens.

细胞色素P-450超基因家族编码酶， 代谢包括药物在内的多种外源性物质， 致癌物和内生素如类固醇和洋地黄素。 在动物中，这些酶的多种形式表现出广泛的， 重叠的底物特异性同时表达， 无论是组成性的还是诱导剂给药后。 到 定义给定细胞色素P-450对细胞周期的贡献。 代谢的特定药物和致癌物质，重要的是， 在缺乏内源性的细胞中单独表达这些酶， 这些酶的背景。 为了实现这一目标，我们开始 开发单个细胞色素P-450的表达系统 蛋白质是由它们的编码DNA序列合成的。 成功 在这方面的努力将使我们能够确定每个人的贡献， 这些酶的诱变和细胞转化， 化学致癌物 为此，我们构建了 感染性重组痘苗病毒和感染性重组体 含有全长编码cDNA序列的逆转录病毒， 小鼠细胞色素P1-450和P3-450。 感染的人类和小鼠细胞 重组病毒表达高水平的真实的 对具有酶活性并显示的蛋白质进行大小调整 底物特异性诊断各自的酶。 初步实验表明，细胞色素P3-450选择性地 激活杂环芳胺和细胞色素P1-450 优先活化芳烃;并且该性质 在限制基质上似乎是相互排斥的 浓度的 此外，细胞色素P3-450活化食品 诱变剂与表达的细胞DNA形成特异性加合物， P3-450 检测到的DNA加合物与 在小鼠或大鼠肝脏中形成 食物诱变剂