title: Functional characterization of 12 allelic variants of CYP2C8 by assessment of paclitaxel 6α-hydroxylation and amodiaquine N-deethylation.
abstract: Cytochrome P450 2C8 (CYP2C8) is one of the enzymes primarily responsible for the metabolism of many drugs, including paclitaxel and amodiaquine. CYP2C8 genetic variants contribute to interindividual variations in the therapeutic efficacy and toxicity of paclitaxel. Although it is difficult to investigate the enzymatic function of most CYP2C8 variants in vivo, this can be investigated in vitro using recombinant CYP2C8 protein variants. The present study used paclitaxel to evaluate 6α-hydroxylase activity and amodiaquine for the N-deethylase activity of wild-type and 11 CYP2C8 variants resulting in amino acid substitutions in vitro. The wild-type and variant CYP2C8 proteins were heterologously expressed in COS-7 cells. Paclitaxel 6α-hydroxylation and amodiaquine N-deethylation activities were determined by measuring the concentrations of 6α-hydroxypaclitaxel and N-desethylamodiaquine, respectively, and the kinetic parameters were calculated. Compared to the wild-type enzyme (CYP2C8.1), CYP2C8.11 and CYP2C8.14 showed little or no activity with either substrate. In addition, the intrinsic clearance values of CYP2C8.8 and CYP2C8.13 for paclitaxel were 68% and 67% that of CYP2C8.1, respectively. In contrast, the CLint values of CYP2C8.2 and CYP2C8.12 were 1.4 and 1.9 times higher than that of CYP2C8.1. These comprehensive findings could inform for further genotype-phenotype studies on interindividual differences in CYP2C8-mediated drug metabolism.
authors.affiliation: Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan.
authors.forename: Chiharu
authors.initials: C
authors.lastname: Tsukada
authors.affiliation: Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Saito
authors.affiliation: Department of Pharmacy, Tohoku University Hospital, Sendai 980-8574, Japan.
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Maekawa
authors.affiliation: Department of Pharmacy, Tohoku University Hospital, Sendai 980-8574, Japan.
authors.forename: Nariyasu
authors.initials: N
authors.lastname: Mano
authors.affiliation: Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa 920-1192, Japan.
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 980-8578, Japan.
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 980-8578, Japan. Electronic address: mhira@m.tohoku.ac.jp.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hiratsuka
mesh_terms: D000483:Alleles; D000655:Amodiaquine / Q000031:analogs & derivatives / Q000493:pharmacokinetics*; D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics* / Q000378:metabolism*; D019556:COS Cells; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D065727:Cytochrome P-450 CYP2C8 / Q000235:genetics* / Q000378:metabolism*; D014644:Genetic Variation; D005822:Genetic Vectors; D006801:Humans; D006900:Hydroxylation; D008958:Models, Molecular; D017239:Paclitaxel / Q000493:pharmacokinetics*; D011110:Polymorphism, Genetic
chemical_list: D000655:Amodiaquine; C047386:desethylamodiaquine; D001189:Aryl Hydrocarbon Hydroxylases; C450259:CYP2C8 protein, human; D065727:Cytochrome P-450 CYP2C8; D017239:Paclitaxel
keywords: Amodiaquine; CYP2C8; Cytochrome P450; Genetic polymorphisms; Paclitaxel