title: Evaluation of the effects of 18 non-synonymous single-nucleotide polymorphisms of CYP450 2C19 on in vitro drug inhibition potential by a fluorescence-based high-throughput assay.
abstract: To comprehensively understand the effects of CYP2C19 genetic polymorphisms on inhibition-based drug-drug interactions (DDIs), 18 human CYP2C19 non-synonymous single-nucleotide polymorphic variants and the wild-type isoform (CYP2C19.1A) were expressed in yeast cells. Using a fluorescence-based high-throughput method, the kinetic constants of these variants, as well as the inhibition constants for 10 drugs, were determined. CYP2C19.5B and CYP2C19.6 showed no activity towards CEC (3-cyano-7-ethoxycoumarin) O-deethylation. CYP2C19.8, CYP2C19.9, CYP2C19.10, CYP2C19.16, CYP2C19.19, E122A and A161P* (an allele containing both A161P and I331V) exhibited significantly reduced catalytic activities compared with CYP2C19.1A. The inhibition assay showed that the CYP2C19 genotype significantly affected the in vitro drug inhibition potential. Although the effect on drug inhibition potential is genotype- and inhibitor-dependent, there was an obvious trend: drugs tended to exhibit higher IC₅₀ values (i.e. decreased inhibition potential) towards variants with reduced activity compared with variants with normal activity. This indicated that patients with reduced-function alleles may be less susceptible to CYP2C19-related DDIs. In this study, we provided the first in vitro evidence of CYP2C19 genotype-dependent effects on drug inhibition potential. This work greatly extends our understanding of the functional consequences of CYP2C19 genetic polymorphisms, and thus should prove valuable for CYP2C19 genotype-based therapy.
authors.affiliation: National Engineering Research Center for Miniaturized Detection Systems, School of Life Sciences, Northwest University, Xi'an, P.R. China.
authors.forename: Huijuan
authors.initials: H
authors.lastname: Wang
authors.forename: Raymond A
authors.initials: RA
authors.lastname: Kim
authors.forename: Dongxu
authors.initials: D
authors.lastname: Sun
authors.forename: Yiwen
authors.initials: Y
authors.lastname: Gao
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Juanli
authors.initials: J
authors.lastname: Zhu
authors.forename: Chao
authors.initials: C
authors.lastname: Chen
mesh_terms: D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics*; D002851:Chromatography, High Pressure Liquid; D003374:Coumarins / Q000378:metabolism; D065731:Cytochrome P-450 CYP2C19; D005453:Fluorescence; D057166:High-Throughput Screening Assays / Q000379:methods*; D006801:Humans; D020128:Inhibitory Concentration 50; D007700:Kinetics; D050505:Mutant Proteins / Q000378:metabolism; D009570:Nitriles / Q000378:metabolism; D004364:Pharmaceutical Preparations / Q000378:metabolism*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000378:metabolism
chemical_list: D003374:Coumarins; D050505:Mutant Proteins; D009570:Nitriles; D004364:Pharmaceutical Preparations; C057714:3-cyano-7-ethoxycoumarin; D001189:Aryl Hydrocarbon Hydroxylases; C045793:CYP2C19 protein, human; D065731:Cytochrome P-450 CYP2C19