title: Genotoxicity of 1-methylpyrene and 1-hydroxymethylpyrene in Chinese hamster V79-derived cells expressing both human CYP2E1 and SULT1A1.
abstract: 1-Methylpyrene (1-MP) is a widespread pollutant that is carcinogenic in animals following metabolic activation. Previous studies have shown that benzylic hydroxylation of 1-MP, catalyzed by multiple CYP isoforms, gives rise to 1-hydroxymethylpyrene (1-HMP), which becomes bioreactive following further metabolism by various sulfotransferase (SULT) isoforms. However, the mutagenic and chromosome damaging effects of 1-MP and 1-HMP in mammalian cells have not been investigated. In this study a Chinese hamster V79-derived cell line expressing both human CYP2E1 and human SULT1A1 was used to investigate the ability of 1-MP and 1-HMP to induce cytotoxicity (using the CCK-8 assay), micronuclei and Hprt gene mutations. The role of each enzyme was investigated through co-exposure in the presence of an enzyme inhibitor. We found that at concentrations of 0.5-4 μM and 5-20 μM, under conditions where no reduction in cell viability/growth occurred, 1-HMP and 1-MP induced micronuclei in V79-hCYP2E1-hSULT1A1 cells in a concentration-dependent manner; however, both compounds were inactive in V79 cells. Similarly, they both caused an increase in Hprt mutant frequency in V79-hCYP2E1-hSULT1A1 cells in these concentration ranges, with 1-MP impairing cell viability/growth at 10 μM and above in the mutagenicity assay. The compounds were again both inactive in V79 cells. The effects of 1-HMP in V79-hCYP2E1-hSULT1A1 cells were blocked or reduced by addition of pentachlorophenol (PCP), a SULT1 inhibitor; the genotoxicity of 1-MP was significantly reduced by either 1-aminobenotrazole, a CYP2E1 inhibitor, or PCP. The results suggest that human CYP2E1 and SULT1A1 cooperate to activate 1-MP and cause genotoxicity in mammalian cells.
authors.affiliation: Department of Toxicology, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Jiang
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Lai
authors.forename: Keqi
authors.initials: K
authors.lastname: Hu
authors.forename: Danxun
authors.initials: D
authors.lastname: Chen
authors.forename: Bixuan
authors.initials: B
authors.lastname: Liu
authors.forename: Yungang
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000818:Animals; D015239:Arylsulfotransferase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D006224:Cricetinae; D003412:Cricetulus; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D000072467:Cytochrome P450 Family 2; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics; D015162:Micronucleus Tests; D009152:Mutagenicity Tests / Q000379:methods*; D009153:Mutagens / Q000633:toxicity; D059645:Mutation Rate; D010416:Pentachlorophenol / Q000494:pharmacology; D011721:Pyrenes / Q000633:toxicity*
chemical_list: D009153:Mutagens; D011721:Pyrenes; D003577:Cytochrome P-450 Enzyme System; C053035:1-methylpyrene; C065833:1-hydroxymethylpyrene; D010416:Pentachlorophenol; C110332:CYP2F1 protein, human; D000072467:Cytochrome P450 Family 2; D007041:Hypoxanthine Phosphoribosyltransferase; D015239:Arylsulfotransferase; C117544:SULT1A1 protein, human
keywords: 1-methylpyrene; CYP2E1; genetically engineered cells; genotoxicity; sulfotransferase (SULT) 1A1