RESUMO
BACKGROUND AND OBJECTIVES: Pioglitazone is a thiazolidinedione antihyperglycemic drug with insulin-sensitizing properties. We investigated whether the variant genotypes of cytochrome P450 2C8 (CYP2C8), CYP2C9, CYP3A5 and transporter ABCB1 influence the pharmacokinetic phenotype of the substrate pioglitazone in Chinese individuals. PARTICIPANTS AND METHODS: Single-nucleotide polymorphisms were determined by the PCR-restriction fragment length polymorphism method in 244 (CYP2C8 and CYP2C9) healthy Chinese Han individuals. After a single oral dose of 30 mg pioglitazone, the plasma concentrations of the parent drug and of two major active metabolites M-III and M-IV were measured using a validated LC-MS/MS in 21 (genotyping CYP3A5 and ABCB1) of these 244 volunteers. RESULTS: The results confirmed that the unique frequencies of CYP2C8*2 (0.0%), CYP2C8*3 (0.0%), and CYP2C9*2 (0.0%) alleles were significantly different from those reported in Whites and Africans, and there were only 10 variant CYP2C9*1/*3 heterozygous (CYP2C9*3 carriers) among 244 Chinese individuals. These results were similar to those reported in Asian ethnic populations, including the Chinese. Unexpectedly, the pioglitazone AUC0-48 in CYP2C9*3 carriers was lower (50.8%), whereas the AUC0-48 ratios of metabolites M-III/pioglitazone and M-IV/pioglitazone increased to 134.3 and 155.8%, respectively, compared with the wild-type CYP2C9*1/*1 homozygous. Moreover, this phenomenon was not observed in individuals with genetic variants of CYP3A5*3 and ABCB1 (C1236T). CONCLUSION: The present research suggests that the CYP2C8, CYP3A5, and ABCB1 genes play no significant role in the interindividual variation of pioglitazone pharmacokinetics, whereas CYP2C9*3 carriers are likely to accelerate the metabolism of this antidiabetic drug in the Chinese Han ethnic population.
Assuntos
Povo Asiático/genética , Redes Reguladoras de Genes , Hipoglicemiantes/administração & dosagem , Polimorfismo de Nucleotídeo Único , Tiazolidinedionas/administração & dosagem , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Administração Oral , Adulto , Povo Asiático/etnologia , China/etnologia , Citocromo P-450 CYP2C8/genética , Citocromo P-450 CYP2C9/genética , Citocromo P-450 CYP3A/genética , Feminino , Genótipo , Humanos , Hipoglicemiantes/farmacocinética , Masculino , Variantes Farmacogenômicos , Pioglitazona , Tiazolidinedionas/farmacocinética , Adulto JovemRESUMO
Cytochrome P450 2W1 (CYP2W1) is expressed specially in certain cancers and could metabolize some substances into cytotoxic antitumor drugs in Caucasian ethnic population. To investigate the genetic polymorphism of CYP2W1 in Chinese, all the nine exons and exon-intron junctions were sequenced by dideoxy chain termination method among 385 Chinese subjects (including 223 Han and 162 Uygur). The present results showed that 40 single nucleotide polymorphisms (SNPs) were detected (14 in the exons and 26 in the introns), 10 were novel variants of which in Chinese. There were 7 novel SNPs in the exons and other 3 novel SNPs in the introns. Four of the 6 novel non-synonymous variations in exons, 131T > C (Leu44Pro), 1289C > A (Ala88Glu), 2027G > A (Arg187Gln) and 5070C > T (Thr383Met) were computationally predicted to affect CYP2W1 protein function, in spite of these variants were heterozygotes. Moreover, the allele frequencies in 6 known SNPs including CYP2W1*2 (2008G > A) and CYP2W1*3 (173A > C) were analyzed, which were significantly lower in Chinese Han (2.9% and 0.0%, respectively) and Uygur (5.2% and 0.0%, respectively) individuals, than those reported previously in Caucasians (9.1% and 33.1%, respectively, P < 0.05). These data provide useful information on the pharmacogenetic studies of CYP2W1 among Chinese and other ethnic populations.