Functional Characterization of 40 CYP3A4 Variants by Assessing Midazolam 1′-Hydroxylation and Testosterone 6β-Hydroxylation
| Autor: | Ai Abe, Akiko Ueda, Masahiro Hiratsuka, Nariyasu Mano, Shu Tadaka, Evelyn Marie Gutiérrez Rico, Sakae Saito, Daisuke Saigusa, Kengo Kinoshita, Eiji Hishinuma, Masamitsu Maekawa, Noriyasu Hirasawa, Akifumi Oda, Tomoki Nakayoshi, Masaki Kumondai |
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| Rok vydání: | 2020 |
| Předmět: |
Pharmacology
chemistry.chemical_classification biology CYP3A4 Pharmaceutical Science Cytochrome P450 Metabolism 030226 pharmacology & pharmacy Hydroxylation 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Enzyme chemistry 030220 oncology & carcinogenesis biology.protein Enzyme kinetics Gene Drug metabolism |
| Zdroj: | Drug Metabolism and Disposition. 49:212-220 |
| ISSN: | 1521-009X 0090-9556 |
| Popis: | CYP3A4 is among the most abundant liver and intestinal drug-metabolizing cytochrome P450 enzymes, contributing to the metabolism of more than 30% of clinically used drugs. Therefore, interindividual variability in CYP3A4 activity is a frequent cause of reduced drug efficacy and adverse effects. In this study, we characterized wild-type CYP3A4 and 40 CYP3A4 variants, including 11 new variants, detected among 4773 Japanese individuals by assessing CYP3A4 enzymatic activities for two representative substrates (midazolam and testosterone). The reduced carbon monoxide–difference spectra of wild-type CYP3A4 and 31 CYP3A4 variants produced with our established mammalian cell expression system were determined by measuring the increase in maximum absorption at 450 nm after carbon monoxide treatment. The kinetic parameters of midazolam and testosterone hydroxylation by wild-type CYP3A4 and 29 CYP3A4 variants (Km, kcat, and catalytic efficiency) were determined, and the causes of their kinetic differences were evaluated by three-dimensional structural modeling. Our findings offer insight into the mechanism underlying interindividual differences in CYP3A4-dependent drug metabolism. Moreover, our results provide guidance for improving drug administration protocols by considering the information on CYP3A4 genetic polymorphisms. SIGNIFICANCE STATEMENT CYP3A4 metabolizes more than 30% of clinically used drugs. Interindividual differences in drug efficacy and adverse-effect rates have been linked to ethnicity-specific differences in CYP3A4 gene variants in Asian populations, including Japanese individuals, indicating the presence of CYP3A4 polymorphisms resulting in the increased expression of loss-of-function variants. This study detected alterations in CYP3A4 activity due to amino acid substitutions by assessing the enzymatic activities of coding variants for two representative CYP3A4 substrates. |
| Databáze: | OpenAIRE |
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