title: Role of human liver cytochrome P450 2C9 in the metabolism of a novel alpha4beta1/alpha4beta7 dual antagonist, TR-14035.
abstract: The metabolism of a novel dual antagonist for alpha4beta1/alpha4beta7 integrin, TR-14035, and the role of polymorphic enzyme responsible for this metabolism were investigated. Human liver microsomes catalyzed the NADPH-dependent metabolism of TR-14035 to a primary metabolite, O-desmethyl TR-14035. This formation was completely blocked by both sulfaphenazole, a selective CYP2C9 inhibitor, and CYP2C9 antibody, whereas potent inhibitors selective for other CYPs exhibited little effects. Of 12 recombinant CYPs examined, O-desmethyl metabolite was principally formed by CYP2C9. CYP1A1, an extrahepatic enzyme, also had this activity (about one-fourth of CYP2C9). Utilizing recombinant CYP2C9*1, K(m) and V(max)/K(m) values of 23.3 microM and 0.284 microL/min/pmol CYP2C9, respectively, were obtained for the O-desmethyl formation, which were quite similar to those in CYP2C9*2 enzyme. In contrast, V(max)/K(m) value in recombinant CYP2C9*3 was approximately one-sixth of CYP2C9*1 and *2. In agreement, kinetics studies using human liver microsomes with CYP2C9*1/*1, *2/*2 and *3/*3 genotypes revealed that the V(max)/K(m) value in *2/*2 microsomes was comparable to that in wild type microsomes, in contrast, that in *3/*3 microsomes was reduced. These results demonstrate CYP2C9 is a primary enzyme mediating the O-desmethylation of TR-14035 in human liver. In homozygotes of CYP2C9*3, the metabolic clearance of TR-14035 should be decreased compared with homozygotes of CYP2C9*1 or 2.
authors.affiliation: Exploratory DMPK, Exploratory Toxicology & DMPK Research Laboratories, Tanabe Seiyaku Co., Ltd., 2-2-50 Kawagishi, Toda, Saitama 33508505, Japan. m-tsuda@tanabe.co.jp
authors.forename: Minoru
authors.initials: M
authors.lastname: Tsuda-Tsukimoto
authors.forename: Yuko
authors.initials: Y
authors.lastname: Ogasawara
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Kume
mesh_terms: D001189:Aryl Hydrocarbon Hydroxylases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D065729:Cytochrome P-450 CYP2C9; D006801:Humans; D066298:In Vitro Techniques; D039041:Integrin alpha4beta1 / Q000037:antagonists & inhibitors*; D016023:Integrins / Q000037:antagonists & inhibitors*; D007527:Isoenzymes / Q000502:physiology; D008862:Microsomes, Liver / Q000201:enzymology*; D010649:Phenylalanine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics*; D011110:Polymorphism, Genetic; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: D039041:Integrin alpha4beta1; D016023:Integrins; D007527:Isoenzymes; C459380:N-(2,6-dichlorobenzoyl)-4-(2',6'-bismethoxyphenyl)phenylalanine; D011994:Recombinant Proteins; C071777:integrin alpha4beta7; D010649:Phenylalanine; C450260:CYP2C9 protein, human; D065729:Cytochrome P-450 CYP2C9; D001189:Aryl Hydrocarbon Hydroxylases