THE ROLE OF CYTOCHROME P-450 ENZYMES IN CARCINOGENESIS

细胞色素 P-450 酶在致癌过程中的作用

• 批准号: 3939702
• 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/3939702
• 关键词: Retroviridae; Retroviridae disease; cell growth regulation; chemical carcinogen; chemical carcinogenesis; complementary DNA; cytochrome P450; drug interactions; enzyme induction /repression; enzyme substrate; gene expression; genetic manipulation; macromolecule; molecular cloning; mutagens; nucleic acid sequence; prostaglandins; steroid hormone; toxin metabolism; vaccinia virus

Cytochrome P-450s are a superfamily of enzymes, some of which are capable of metabolizing xenobiotics such as drugs and carcinogens as well as endobiotics such as steroids and prostaglandins. In animals, multiple forms of these enzymes are expressed simultaneously either constitutively or after administration of specific inducers. These enzymes display overlapping substrate specificities. Thus, a single cytochrome P- 450 may metabolize multiple substrates and a single substrate may be acted upon by several cytochrome P-450s. Some of the cytochrome P-450 catalytic products bind to cellular macromolecules and thus are presumed to initiate mutagenesis and carcinogenesis. In order 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. For this purpose, we have begun to develop expression systems in which an individual cytochrome P-450 protein is synthesized from its full length cDNA. Success in this effort will enable us to define the contribution of each of these enzymes to mutagenesis and cell transformation mediated by chemical carcinogens. For this purpose, we employed two types of expression systems, namely recombinant vaccinia virus and recombinant retrovirus. 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 as detected by immunoblotting. The expressed proteins are enzymatically active and displayed substrate specificities characteristics of the respective enzymes. Experiments to determine the catalytic specificities and the contribution of the enzymes to mutagenesis are in progress.

细胞色素P-450是酶的超家族，其中一些酶 能够代谢异生物质如药物， 致癌物以及内源性物质，如类固醇， 兰丁 在动物中，这些酶的多种形式是 同时表达，无论是组成上还是之后 特定诱导剂的施用。 这些酶显示 重叠底物特异性。 因此，单个细胞色素P- 450可以代谢多种底物和单一底物 可能会受到几种细胞色素P-450的影响。 一些 细胞色素P-450催化产物与细胞结合 大分子，并因此被假定为启动诱变 和致癌作用。 为了定义一个给定的 细胞色素P-450对特定药物的代谢， 致癌物，重要的是要表达这些酶单独。 为此，我们已经开始开发表达系统， 单个细胞色素P-450蛋白质由其合成 其全长cDNA。 这一努力的成功将使我们能够 确定这些酶中的每一种对诱变的贡献 和化学致癌物介导的细胞转化。 为此，我们采用了两种类型的表达系统， 即重组牛痘病毒和重组逆转录病毒。 我们构建了感染性重组痘苗病毒， 含有全长的感染性重组逆转录病毒 编码小鼠细胞色素P1-450和P3- 450的cDNA序列， 450. 用重组体感染的人和小鼠细胞 病毒表达高水平的真实大小蛋白， 通过免疫印迹检测。 表达的蛋白质是 具有酶活性和底物特异性 各酶的特性。 实验来 确定催化特异性和贡献的 酶致突变正在进行中。