ABSTRACT
AIM: To investigate whether single-nucleotide polymorphisms (SNPs) in the P450 oxidoreductase (POR) gene were correlated with interindividual variations in cytochrome P450 (CYP) 2B6 activity. METHODS: Thirty-six healthy volunteers who tested CYP2B6 and POR polymorphisms were enrolled in the study. CYP2B6 activity was measured by bupropion hydroxylation with LC/MS/MS. The ratio of hydroxybupropion versus bupropion (AUC_hyd/AUC_bup) in terms of area under the time-concentration curve (AUC) was used to represent the CYP2B6 activity. RESULTS: The volunteers carrying CYP2B6*1/*1 showed a significantly higher mean AUC_hyd/ AUC_bup than those CYP2B6*1/*6 and CYP2B6*6/*6 variants (15.66 ± 1.65 vs. 9.25 ± 1.92, P = 0.008 and 15.66 ± 1.65 vs. 8.21 ± 1.74, P = 0.006, respectively). POR rs2868177 (6593 A > G) AA homozygotes showed a significantly lower mean AUC_hyd/ AUC_bup than that of POR rs2868177 AG heterozygotes or GG homozygotes (8.13 ± 1.37 vs. 12.15 ± 2.97, P = 0.005 and 8.13 ± 1.37 vs. 17.59 ± 3.25, P = 0.001, respectively). Moreover, POR rs2868177 AG heterozygotes and GG homozygotes showed a significantly increased mean AUC_hyd/AUC_bup than AA homozygotes in the CYP2B6*1/*1 and CYP2B6*6 carriers (16.40 ± 2.01 vs. 12.40 ± 1.45, P = 0.006 and 10.65 ± 1.47 vs. 6.54 ± 1.25, P = 0.004, respectively). Meanwhile, a strong correlation between the genetic variations (POR rs2868177 and CYP2B6*6) and AUC_hyd/ AUC_bup was found (P = 0.009 and P = 0.001, respectively). There was no significant difference in the mean AUC_hyd/AUC_bup among different POR *28 genotypes (P > 0.05). CONCLUSION: POR rs2868177 and CYP2B6*6 variants contribute to the interindividual variability in human CYP2B6 activity, which may affect the disposition and interaction of other CYP2B6 substrate drugs.
Subject(s)
Cytochrome P-450 CYP2B6/genetics , Cytochrome P-450 CYP2B6/metabolism , Cytochrome P-450 Enzyme System/genetics , Adult , Area Under Curve , Asian People/genetics , Bupropion/analogs & derivatives , Bupropion/blood , Bupropion/pharmacokinetics , Gene Frequency , Genotype , Healthy Volunteers , Humans , Hydroxylation , Male , Polymorphism, Single Nucleotide , Young AdultABSTRACT
PURPOSE: The purpose of this study is to evaluate the association between variants in prostaglandin-endoperoxide synthase 1 (PTGS1), prostaglandin F (2α) receptor (PTGFR), and multidrug resistance protein 4 (MRP4) genes and intraocular pressure (IOP) response to latanoprost in Chinese patients with primary open-angle glaucoma (POAG). METHODS: The IOP response to latanoprost was evaluated by percent IOP reduction (%ΔIOP) in the treated eye with the formula %ΔIOP = (Baseline IOP values - IOP values posttreatment) / Baseline IOP values × 100 %. Polymorphisms in PTGS1 (rs3842787 and rs10306114), PTGFR (rs3753380 and rs3766355), and MRP4 (rs11568658 and rs11568668) genes were detected by direct DNA sequencing. The differences among %ΔIOP of genotypes or haplotypes were obtained by use of the Mann-Whitney U test. Association analyses were performed by multiple linear regression analysis. RESULTS: Latanoprost were prescribed to 63 subjects, 60 of which met the inclusion/exclusion criteria for the current study. Notably, the %ΔIOP in the rs11568658 GT heterozygous genotype was 10.4 %ΔIOP lower than that of GG homozygous wild-type on day 7 (15.7 ± 2.52 vs. 26.1 ± 2.88, P=0.003), and the corresponding results in the rs10306114 AG heterozygous genotype and AT haplotype constructed by rs3753380 and rs3766355 on day 7 were 7.2 and 10.3 %ΔIOP (P<0.05). Interestingly, similar results were also observed on day 30 (P=0.008, P=0.006, and P=0.002, respectively). Multiple regression analysis showed that heterozygous genotypes of rs10306114, rs11568658, and carrier of AT haplotype were significantly correlated with the lower %ΔIOP. On day 30, the above variations explained 9.9, 10.7, and 17.7 % of the total variability of %ΔIOP in the Chinese POAG patients, respectively. CONCLUSION: rs10306114, rs3753380, rs3766355, and rs11568658 single-nucleotide polymorphisms (SNPs) correlate with a response to latanoprost treatment in patients with POAG. These SNPs may be important determinants of variability in response to latanoprost.
