5 OF 12 FORMS OF VACCINIA VIRUS-EXPRESSED HUMAN HEPATIC CYTOCHROME-P450 METABOLICALLY ACTIVATE AFLATOXIN-B1
5 OF 12 FORMS OF VACCINIA VIRUS-EXPRESSED HUMAN HEPATIC CYTOCHROME-P450 METABOLICALLY ACTIVATE AFLATOXIN-B1
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DOI：
10.1073/pnas.87.12.4790
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发表时间：
1990-06-01
影响因子：
11.1
通讯作者：
GONZALEZ, FJ
中科院分区：
文献类型：
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作者：
AOYAMA, T;YAMANO, S;GONZALEZ, FJ
用重组痘苗病毒在肝癌细胞中表达了12种人肝细胞色素P450。表达的P450被分析其激活强有力的肝癌原黄曲霉毒素B1的代谢产物具有致突变或DNA结合特性的能力。通过在艾姆斯试验中鼠伤寒沙门氏菌His回复突变体的产生，评估了五种形式（P450 s IA 2、IIA 3、IIB 7、IIA 3和IIIA 4）将黄曲霉毒素B1活化为致突变代谢物。相同的P450催化黄曲霉毒素B1转化为DNA结合的衍生物，通过原位测定判断，其中放射性标记的致癌物与表达单个P450形式的细胞一起孵育。通过艾姆斯试验和DNA结合试验测定，其他7种人P450（IIC 8、IIC 9、IID 6、IIE 1、IIF 1、IIIA 5和IVB 1）均未显著激活黄曲霉毒素B1。此外，多克隆抗大鼠肝P450抗体，与个人P450的IA 2，IIA 3，IIIA 3和IIIA 4交叉反应，每个抑制黄曲霉毒素B1激活催化的人肝S-9提取物。抑制范围从低至10%（抗IIA 3抗体）到高达65%（抗IIIA 3和IIIA 4抗体）。这些结果表明，人肝脏中黄曲霉毒素B1的代谢活化涉及多种形式的P450的贡献。
Twelve forms of human hepatic cytochrome P450 were expressed in hepatoma cells by means of recombinant vaccinia viruses. The expressed P450s were analyzed for their abilities to activate the potent hepatocarcinogen aflatoxin B1 to metabolites having mutagenic or DNA-binding properties. Five forms, P450s IA2, IIA3, IIB7, IIA3, and IIIA4, activated aflatoxin B1 to mutagenic metabolites as assessed by the production of His revertants of Salmonella typhimurium in the Ames test. The same P450s catalyzed conversion of aflatoxin B1 to DNA-bound derivatives as judged by an in situ assay in which the radiolabeled carcinogen was incubated with cells expressing the individual P450 forms. Seven other human P450s, IIC8, IIC9, IID6, IIE1, IIF1, IIIA5, and IVB1, did not significantly activate aflatoxin B1 as measured by both the Ames test and the DNA-binding assay. Moreover, polyclonal anti-rat liver P450 antibodies that crossreact with individual human P450s IA2, IIA3, IIIA3, and IIIA4 each inhibited aflatoxin B1 activation catalyzed by human liver S-9 extracts. Inhibition ranged from as low as 10% with antibody against IIA3 to as high as 65% with antibody against IIIA3 and IIIA4. These results establish that metabolic activation of aflatoxin B1 in human liver involves the contribution of multiple forms of P450.