A Comprehensive Investigation of 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) Metabolism in the Mouse Using a Multivariate Data Analysis Approach
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- 作者：Chi Chen ; Xiaochao Ma ; Michael A. Malfatti ; Kristopher W. Krausz ; Shioko Kimura ; James S. Felton ; Jeffrey R. Idle ; Frank J. Gonzalez
- 刊名：Chemical Research in Toxicology
- 出版年：2007
- 出版时间：March 2007
- 年：2007
- 卷：20
- 期：3
- 页码：531 - 542
- 全文大小：590K
- 年卷期：v.20,no.3(March 2007)
- ISSN：1520-5010
文摘
2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a potent rodent carcinogen and a potentialhuman carcinogen because of its existence in the normal human diet. N2-OH-PhIP, a major PhIP metabolite,has been identified as a precursor of genotoxic species. In vitro data supported the view that CYP1A2is the major enzyme responsible for the formation of N2-OH-PhIP. However, disruption of the CYP1A2gene in mouse failed to inhibit PhIP-induced carcinogenesis. To investigate the mechanism underlyingthis observation, the metabolism of PhIP in wild-type, Cyp1a2-null, and CYP1A2-humanized mice wasexamined in detail using a metabolomic approach. Following data acquisition in a high-resolution LC-MS system, urinary metabolomes of the control and PhIP-treated mice were characterized in a principalcomponent analysis (PCA) model. Comprehensive metabolite profiles of PhIP in high dose (10 mg/kg)and low dose (100 
g/kg) were established through analyzing urinary ions contributing to the separationof three mouse lines in the multivariate model and by measuring radiolabled PhIP metabolite in a radio-HPLC assay, respectively. The genotoxicity of PhIP to three mouse lines was evaluated by measuringDNA adduction levels in liver, lung, colon, and mammary gland. On the basis of the chemical identitiesof 17 urinary PhIP metabolites, including eight novel metabolites, multivariate data analysis revealed therole of CYP1A2 in PhIP metabolism and a human-mouse interspecies difference in the catalytic activityof CYP1A2. In addition, the results also showed that Cyp1a2-null mice still possess significant N2-hydroxylation and DNA adduction activities, which may be partially attributed to mouse CYP2C enzymesaccording to the results from in vitro microsome and Supersome incubations and antibody inhibitionexperiments.
g/kg) were established through analyzing urinary ions contributing to the separationof three mouse lines in the multivariate model and by measuring radiolabled PhIP metabolite in a radio-HPLC assay, respectively. The genotoxicity of PhIP to three mouse lines was evaluated by measuringDNA adduction levels in liver, lung, colon, and mammary gland. On the basis of the chemical identitiesof 17 urinary PhIP metabolites, including eight novel metabolites, multivariate data analysis revealed therole of CYP1A2 in PhIP metabolism and a human-mouse interspecies difference in the catalytic activityof CYP1A2. In addition, the results also showed that Cyp1a2-null mice still possess significant N2-hydroxylation and DNA adduction activities, which may be partially attributed to mouse CYP2C enzymesaccording to the results from in vitro microsome and Supersome incubations and antibody inhibitionexperiments.