title: Functional Characterization of 34 CYP2A6 Allelic Variants by Assessment of Nicotine C-Oxidation and Coumarin 7-Hydroxylation Activities.
abstract: CYP2A6, a member of the cytochrome P450 (P450) family, is one of the enzymes responsible for the metabolism of therapeutic drugs and such tobacco components as nicotine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, and N-nitrosodiethylamine. Genetic polymorphisms in CYP2A6 are associated with individual variation in smoking behavior, drug toxicities, and the risk of developing several cancers. In this study, we conducted an in vitro analysis of 34 allelic variants of CYP2A6 using nicotine and coumarin as representative CYP2A6 substrates. These variant CYP2A6 proteins were heterologously expressed in 293FT cells, and their enzymatic activities were assessed on the basis of nicotine C-oxidation and coumarin 7-hydroxylation activities. Among the 34 CYP2A6 variants, CYP2A6.2, CYP2A6.5, CYP2A6.6, CYP2A6.10, CYP2A6.26, CYP2A6.36, and CYP2A6.37 exhibited no enzymatic activity, whereas 14 other variants exhibited markedly reduced activity toward both nicotine and coumarin. These comprehensive in vitro findings may provide useful insight into individual differences in smoking behavior, drug efficacy, and cancer susceptibility.
authors.affiliation: Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (H.H., M.K., N.H., M.H.), Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, Japan (M.M., H.Y., N.M.), Department of Biophysical Chemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan (A.O.).
authors.forename: Hiroki
authors.initials: H
authors.lastname: Hosono
authors.affiliation: Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (H.H., M.K., N.H., M.H.), Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, Japan (M.M., H.Y., N.M.), Department of Biophysical Chemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan (A.O.).
authors.forename: Masaki
authors.initials: M
authors.lastname: Kumondai
authors.affiliation: Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (H.H., M.K., N.H., M.H.), Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, Japan (M.M., H.Y., N.M.), Department of Biophysical Chemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan (A.O.).
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Maekawa
authors.affiliation: Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (H.H., M.K., N.H., M.H.), Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, Japan (M.M., H.Y., N.M.), Department of Biophysical Chemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan (A.O.).
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Yamaguchi
authors.affiliation: Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (H.H., M.K., N.H., M.H.), Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, Japan (M.M., H.Y., N.M.), Department of Biophysical Chemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan (A.O.).
authors.forename: Nariyasu
authors.initials: N
authors.lastname: Mano
authors.affiliation: Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (H.H., M.K., N.H., M.H.), Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, Japan (M.M., H.Y., N.M.), Department of Biophysical Chemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan (A.O.).
authors.forename: Akifumi
authors.initials: A
authors.lastname: Oda
authors.affiliation: Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (H.H., M.K., N.H., M.H.), Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, Japan (M.M., H.Y., N.M.), Department of Biophysical Chemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan (A.O.).
authors.forename: Noriyasu
authors.initials: N
authors.lastname: Hirasawa
authors.affiliation: Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (H.H., M.K., N.H., M.H.), Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, Japan (M.M., H.Y., N.M.), Department of Biophysical Chemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan (A.O.) mhira@m.tohoku.ac.jp.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hiratsuka
mesh_terms: D000483:Alleles; D003367:Cotinine / Q000378:metabolism; D003374:Coumarins / Q000378:metabolism*; D065637:Cytochrome P-450 CYP2A6 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D006900:Hydroxylation; D007700:Kinetics; D008861:Microsomes / Q000201:enzymology / Q000378:metabolism; D008958:Models, Molecular; D009538:Nicotine / Q000378:metabolism*; D010084:Oxidation-Reduction; D011110:Polymorphism, Genetic; D013379:Substrate Specificity; D014162:Transfection; D014468:Umbelliferones / Q000378:metabolism
chemical_list: D003374:Coumarins; D014468:Umbelliferones; C031477:7-hydroxycoumarin; D009538:Nicotine; C030123:coumarin; C585710:CYP2A6 protein, human; D065637:Cytochrome P-450 CYP2A6; D003367:Cotinine