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Sample records for 2c9 2c19 2d6

  1. Analysis of genetic variations in CYP2C9, CYP2C19, CYP2D6 and CYP3A5 genes using oligonucleotide microarray

    PubMed Central

    Dong, Yuanyuan; Xiao, Huasheng; Wang, Qi; Zhang, Chunxiu; Liu, Xiuming; Yao, Na; Sheng, Haihui; Li, Haiyan

    2015-01-01

    The cytochrome P450 enzymes play a critical role in the metabolism of many commonly prescribed drugs. Among them, the most important enzymes are highly polymorphic CYP2C9, CYP2C19, CYP2D6 and CYP3A5, which are responsible for about 40% of the metabolism of clinical used drugs. Here we developed a novel CYP450 oligonucleotide microarray that allow for detection of 32 known variations of CYP genes from a single multiplex reaction, including 19 polymorphisms of CYP2D6 gene, 8 polymorphisms of CYP2C9 gene, 4 polymorphisms of CYP2C19 gene and 1 polymorphism of CYP3A5 gene. 229 genomic DNA samples from unrelated Han subjects were analyzed. The microarray results showed to have high call rate and accuracy according to concordance with genotypes identified by independent bidirectional sequencing. Furthermore, we found that the major CYP2C9, CYP2C19, CYP2D6 and CYP3A5 alleles in Chinese Han population were CYP2C9*3 (allelic frequency of 10.7%), CYP2C9*2 (20.31%), CYP2C19*2 (5.68%), CYP2D6*10 (58.52%), CYP2D6*2 (13.76) and CYP3A5*3 (70.69%). With flexible DNA preparation, the microarray can significantly facilitates the process of detecting genetics variations in CYP2C9, CYP2C19, CYP2D6 and CYP3A5 gene and provide safe and effective therapy for individual patients. PMID:26770516

  2. Allele and genotype frequencies of CYP2C9, CYP2C19 and CYP2D6 in an Italian population.

    PubMed

    Scordo, Maria Gabriella; Caputi, Achille P; D'Arrigo, Concetta; Fava, Giuseppina; Spina, Edoardo

    2004-08-01

    The polymorphic cytochrome P450 isoenzymes (CYPs) 2C9, 2C19 and 2D6 metabolise many important drugs, as well as other xenobiotics. Their polymorphism gives rise to important interindividual and interethnic variability in the metabolism and disposition of several therapeutic agents and may cause differences in the clinical response to these drugs. In this study, we determined the genotype profile of a random Italian population in order to compare the CYP2C9, CYP2C19 and CYP2D6 allele frequencies among Italians with previous findings in other Caucasian populations. Frequencies for the major CYP2C9, CYP2C19 and CYP2D6 mutated alleles and genotypes have been evaluated in 360 unrelated healthy Italian volunteers (210 males and 150 females, aged 19-52 years). Genotyping has been carried out on peripheral leukocytes DNA by molecular biology techniques (PCR, RFLP, long-PCR). CYP2C9, CYP2C19 and CYP2D6 allele and genotype frequencies resulted in equilibrium with the Hardy-Weinberg equation. One hundred and fourteen subjects (31.7%) carried one and 23 subjects (6.4%) carried two CYP2C9 mutated alleles. Sixty-eight (18.9%) volunteers were found to be heterozygous and six (1.7%) homozygous for the CYP2C19*2, while no CYP2C19*3 was detected in the evaluated population. Volunteers could be divided into four CYP2D6 genotypes groups: 192 subjects (53.3%) with no mutated alleles (homozygous extensive metabolisers, EM), 126 (35.0%) with one mutated allele (heterozygous EM), 12 (3.4%) with two mutated alleles (poor metabolisers, PM) and 30 (8.3%) with extracopies of a functional gene (ultrarapid metabolisers, UM). Frequencies of both CYP2C9 and CYP2C19 allelic variants, as well as CYP2D6 detrimental alleles, in Italian subjects were similar to those of other Caucasian populations. Conversely, the prevalence of CYP2D6 gene duplication among Italians resulted very high, confirming the higher frequency of CYP2D6 UM in the Mediterranean area compared to Northern Europe. PMID:15177309

  3. Pharmacokinetic assessment of a five-probe cocktail for CYPs 1A2, 2C9, 2C19, 2D6 and 3A

    PubMed Central

    Turpault, Sandrine; Brian, William; Van Horn, Robert; Santoni, Alix; Poitiers, Franck; Donazzolo, Yves; Boulenc, Xavier

    2009-01-01

    AIMS To assess the pharmacokinetics (PK) of selective substrates of CYP1A2 (caffeine), CYP2C9 (S-warfarin), CYP2C19 (omeprazole), CYP2D6 (metoprolol) and CYP3A (midazolam) when administered orally and concurrently as a cocktail relative to the drugs administered alone. METHODS This was an open-label, single-dose, randomized, six-treatment six-period six-sequence William's design study with a wash-out of 7 or 14 days. Thirty healthy male subjects received 100 mg caffeine, 100 mg metoprolol, 0.03 mg kg−1 midazolam, 20 mg omeprazole and 10 mg warfarin individually and in combination (cocktail). Poor metabolizers of CYP2C9, 2C19 and 2D6 were excluded. Plasma samples were obtained up to 48 h for caffeine, metoprolol and omeprazole, 12 h for midazolam, 312 h for warfarin and the cocktail. Three different validated liquid chromatography tandem mass spectrometry methods were used. Noncompartmental PK parameters were calculated. Log-transformed Cmax, AUClast and AUC for each analyte were analysed with a linear mixed effects model with fixed term for treatment, sequence and period, and random term for subject within sequence. Point estimates (90% CI) for treatment ratios (individual/cocktail) were computed for each analyte Cmax, AUClast and AUC. RESULTS There was no PK interaction between the probe drugs when administered in combination as a cocktail, relative to the probes administered alone, as the 90% CI of the PK parameters was within the prespecified bioequivalence limits of 0.80, 1.25. CONCLUSION The lack of interaction between probes indicates that this cocktail could be used to evaluate the potential for multiple drug–drug interactions in vivo. PMID:20002088

  4. Combination Analysis in Genetic Polymorphisms of Drug-Metabolizing Enzymes CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A5 in the Japanese Population

    PubMed Central

    Ota, Tomoko; Kamada, Yuka; Hayashida, Mariko; Iwao-Koizumi, Kyoko; Murata, Shigenori; Kinoshita, Kenji

    2015-01-01

    The Cytochrome P450 is the major enzyme involved in drug metabolism. CYP enzymes are responsible for the metabolism of most clinically used drugs. Individual variability in CYP activity is one important factor that contributes to drug therapy failure. We have developed a new straightforward TaqMan PCR genotyping assay to investigate the prevalence of the most common allelic variants of polymorphic CYP enzymes CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A5 in the Japanese population. Moreover, we focused on the combination of each genotype for clinical treatment. The genotype analysis identified a total of 139 out of 483 genotype combinations of five genes in the 1,003 Japanese subjects. According to our results, most of subjects seemed to require dose modification during clinical treatment. In the near future, modifications should be considered based on the individual patient genotype of each treatment. PMID:25552922

  5. Inhibitory effects of phthalimide derivatives on the activity of the hepatic cytochrome P450 monooxygenases CYP2C9 and CYP2C19.

    PubMed

    Kolukisaoglu, Üner; Wendler, Christian; Goerdes, Dirk; Diener, Annette; Thurow, Kerstin

    2010-12-01

    Affecting hepatic cytochrome (CYP) activity is one of the major concerns in drug-drug interaction. Thus the testing of drug candidates on their impact on these enzymes is an essential step in early drug discovery. We tested a collection of 480 in-house phthalimide derivatives against different CYP450s using a high throughput inhibition assay. In initial tests with the isoform CYP2C19 about 57.5% of the tested phthalimide derivatives showed significantly enhanced inhibitory effects against this enzyme. In addition similar patterns of phthalimide inhibition for CYP2C9 and CYP2C19 were found, whereas the unrelated isoforms CYP2D6 and CYP3A4 were not specifically affected. Also less than 10% of randomly chosen substances inhibited CYP2C9. Analyses of structure-function relationships revealed that the substituent at the nitrogen atom in the isoindole ring is of crucial impact for the activity of CYP2C9/19.

  6. In vitro inhibition of the cytochrome P450 (CYP450) system by the antiplatelet drug ticlopidine: potent effect on CYP2C19 and CYP2D6

    PubMed Central

    Ko, Jae Wook; Desta, Zeruesenay; Soukhova, Nadia V; Tracy, Timothy; Flockhart, David A

    2000-01-01

    Aims To examine the potency of ticlopidine (TCL) as an inhibitor of cytochrome P450s (CYP450s) in vitro using human liver microsomes (HLMs) and recombinant human CYP450s. Methods Isoform-specific substrate probes of CYP1A2, 2C19, 2C9, 2D6, 2E1 and 3A4 were incubated in HLMs or recombinant CYPs with or without TCL. Preliminary data were generated to simulate an appropriate range of substrate and inhibitor concentrations to construct Dixon plots. In order to estimate accurately inhibition constants (Ki values) of TCL and determine the type of inhibition, data from experiments with three different HLMs for each isoform were fitted to relevant nonlinear regression enzyme inhibition models by WinNonlin. Results TCL was a potent, competitive inhibitor of CYP2C19 (Ki = 1.2 ± 0.5 µm) and of CYP2D6 (Ki = 3.4 ± 0.3 µm). These Ki values fell within the therapeutic steady-state plasma concentrations of TCL (1–3 µm). TCL was also a moderate inhibitor of CYP1A2 (Ki = 49 ± 19 µm) and a weak inhibitor of CYP2C9 (Ki > 75 µm), but its effect on the activities of CYP2E1 (Ki = 584 ± 48 µm) and CYP3A (> 1000 µm) was marginal. Conclusions TCL appears to be a broad-spectrum inhibitor of the CYP isoforms, but clinically significant adverse drug interactions are most likely with drugs that are substrates of CYP2C19 or CYP2D6. PMID:10759690

  7. Interactions between CYP2C9 and CYP2C19 in reconstituted binary systems influence their catalytic activity: possible rationale for the inability of CYP2C19 to catalyze methoxychlor demethylation in human liver microsomes.

    PubMed

    Hazai, Eszter; Kupfer, David

    2005-01-01

    Previous studies in our laboratory showed that among cDNA-expressed human cytochrome P450 (P450) supersomes, CYP2C19 was the most active in methoxychlor-O-demethylation. However, based on the lack of inhibition of methoxychlor-O-demethylation by monoclonal anti-CYP2C19 antibodies in human liver microsomes (HLM), CYP2C19 did not seem to catalyze that reaction in HLM. By contrast, CYP2C9, much less active than CYP2C19 in supersomes, was the most active in HLM. The current study examines whether the lack of methoxychlor-O-demethylation by CYP2C19 in HLM was due to CYP2C19 exhibiting inferior competition for the NADPH-cytochrome P450 reductase (CPR) versus CYP2C9 and explores the interactions between CYP2C9 and CYP2C19 in a singular and binary complex of a reconstituted system. When reconstituted with CPR, cytochrome b(5), and lipid, purified CYP2C19 and CYP2C9 catalyzed methoxychlor-O-demethylation. However, whereas equimolar CPR to CYP2C9 supported maximal rates of methoxychlor demethylation and diclofenac hydroxylation, the rate of methoxychlor demethylation by CYP2C19 was not fully saturated, even with a 9-fold molar excess of CPR over CYP2C19. This behavior of CYP2C19 was also observed with S-mephenytoin as the substrate. When a binary reconstitution system was prepared by mixing CYP2C9 and CYP2C19 enzymes, methoxychlor-O-demethylation and S-mephenytoin hydroxylation by CYP2C19 were dramatically inhibited. Inhibition depended on the amount of CPR and substrate used. By contrast, in the incubation containing CYP2C9, diclofenac hydroxylation was activated by the presence of CYP2C19. These results show that interactions among P450 enzymes can modulate their catalytic rates, which depend on the substrate undergoing metabolism.

  8. CYP2C9, CYP2C19, ABCB1 genetic polymorphisms and phenytoin plasma concentrations in Mexican-Mestizo patients with epilepsy.

    PubMed

    Ortega-Vázquez, A; Dorado, P; Fricke-Galindo, I; Jung-Cook, H; Monroy-Jaramillo, N; Martínez-Juárez, I E; Familiar-López, I; Peñas-Lledó, E; LLerena, A; López-López, M

    2016-06-01

    We aimed to explore the possible influence of CYP2C9 (*2, *3 and IVS8-109 A>T), CYP2C19 (*2, *3 and *17) and ABCB1 (1236C>T, 2677G>A/T and 3435C>T) on phenytoin (PHT) plasma concentrations in 64 Mexican Mestizo (MM) patients with epilepsy currently treated with PHT in mono- (n=25) and polytherapy (n=39). Genotype and allele frequencies of these variants were also estimated in 300 MM healthy volunteers. Linear regression models were used to assess associations between the dependent variables (PHT plasma concentration and dose-corrected PHT concentration) with independent variables (CYP2C9, CYP2C19 and ABCB1 genotypes, ABCB1 haplotypes, age, sex, weight, and polytherapy). In multivariate models, CYP2C9 IVS8-109 T was significantly associated with higher PHT plasma concentrations (t(64)=2.27; P=0.03). Moreover, this allele was more frequent in the supratherapeutic group as compared with the subtherapeutic group (0.13 versus 0.03, respectively; P=0.05, Fisher's exact test). Results suggest that CYP2C9 IVS8-109 T allele may decrease CYP2C9 enzymatic activity on PHT. More research is needed to confirm findings.

  9. Distribution of CYP2D6 and CYP2C19 Polymorphisms Associated with Poor Metabolizer Phenotype in Five Amerindian Groups and Western Mestizos from Mexico

    PubMed Central

    Salazar-Flores, Joel; Torres-Reyes, Luis A.; Martínez-Cortés, Gabriela; Rubi-Castellanos, Rodrigo; Sosa-Macías, Martha; Muñoz-Valle, José F.; González-González, César; Ramírez, Angélica; Román, Raquel; Méndez, José L.; Barrera, Andrés; Torres, Alfredo; Medina, Rafael

    2012-01-01

    Background: The distribution of polymorphisms in the CYP2D6 and CYP2C19 genes allows inferring the potential risk for specific adverse drug reactions and lack of therapeutic effects in humans. This variability shows differences among human populations. The aim of this study was to analyze single-nucleotide polymorphisms related to a poor metabolizer (PM) phenotype in nonpreviously studied Amerindian groups and Mestizos (general admixed population) from Mexico. Methods: We detected by SNaPshot® different polymorphisms located in CYP2D6 (*3, *4, *6, *7, and *8) and CYP2C19 (*2, *3, *4 and *5) in western Mestizos (n=145) and five Amerindian groups from Mexico: Tarahumaras from the North (n=88); Purépechas from the Center (n=101); and Tojolabales (n=68), Tzotziles (n=88), and Tzeltales (n=20) from the Southeast. Genotypes were observed by capillary electrophoresis. The genetic relationships among these populations were estimated based on these genes. Results and Discussion: The wild-type allele (*1) of both genes was predominant in the Mexican populations studied. The most widely observed alleles were CYP2C19*2 (range, 0%–31%) and CYP2D6*4 (range, 1.2%–7.3%), whereas CYP2D6*3 was exclusively detected in Mestizos. Conversely, CYP2C19*4 and *5, as well as CYP2D6*3, *6, *7, and *8, were not observed in the majority of the Mexican populations. The Tarahumaras presented a high frequency of the allele CYP2C19*2 (31%) and of homozygotes *2/*2 (10.7%), which represent a high frequency of potentially PM phenotypes in this Amerindian group. The genetic distances showed high differentiation of Tarahumaras (principally for CYP2C19 gene). In general, a relative proximity was observed between most of the Amerindian, Mexican-Mestizo, and Latin-American populations. Conclusion: In general, the wild-type allele (*1) predominates in Mexican populations, outlining a relatively homogeneous distribution for CYP2C19 and CYP2D6. The exception is the Tarahumara group that displays a

  10. Generation of in-silico cytochrome P450 1A2, 2C9, 2C19, 2D6, and 3A4 inhibition QSAR models.

    PubMed

    Gleeson, M Paul; Davis, Andrew M; Chohan, Kamaldeep K; Paine, Stuart W; Boyer, Scott; Gavaghan, Claire L; Arnby, Catrin Hasselgren; Kankkonen, Cecilia; Albertson, Nan

    2007-01-01

    In-silico models were generated to predict the extent of inhibition of cytochrome P450 isoenzymes using a set of relatively interpretable descriptors in conjunction with partial least squares (PLS) and regression trees (RT). The former was chosen due to the conservative nature of the resultant models built and the latter to more effectively account for any non-linearity between dependent and independent variables. All models are statistically significant and agree with the known SAR and they could be used as a guide to P450 liability through a classification based on the continuous pIC50 prediction given by the model. A compound is classified as having either a high or low P450 liability if the predicted pIC(50) is at least one root mean square error (RMSE) from the high/low pIC(50) cut-off of 5. If predicted within an RMSE of the cut-off we cannot be confident a compound will be experimentally low or high so an indeterminate classification is given. Hybrid models using bulk descriptors and fragmental descriptors do significantly better in modeling CYP450 inhibition, than bulk property QSAR descriptors alone.

  11. Construction of Metabolism Prediction Models for CYP450 3A4, 2D6, and 2C9 Based on Microsomal Metabolic Reaction System

    PubMed Central

    He, Shuai-Bing; Li, Man-Man; Zhang, Bai-Xia; Ye, Xiao-Tong; Du, Ran-Feng; Wang, Yun; Qiao, Yan-Jiang

    2016-01-01

    During the past decades, there have been continuous attempts in the prediction of metabolism mediated by cytochrome P450s (CYP450s) 3A4, 2D6, and 2C9. However, it has indeed remained a huge challenge to accurately predict the metabolism of xenobiotics mediated by these enzymes. To address this issue, microsomal metabolic reaction system (MMRS)—a novel concept, which integrates information about site of metabolism (SOM) and enzyme—was introduced. By incorporating the use of multiple feature selection (FS) techniques (ChiSquared (CHI), InfoGain (IG), GainRatio (GR), Relief) and hybrid classification procedures (Kstar, Bayes (BN), K-nearest neighbours (IBK), C4.5 decision tree (J48), RandomForest (RF), Support vector machines (SVM), AdaBoostM1, Bagging), metabolism prediction models were established based on metabolism data released by Sheridan et al. Four major biotransformations, including aliphatic C-hydroxylation, aromatic C-hydroxylation, N-dealkylation and O-dealkylation, were involved. For validation, the overall accuracies of all four biotransformations exceeded 0.95. For receiver operating characteristic (ROC) analysis, each of these models gave a significant area under curve (AUC) value >0.98. In addition, an external test was performed based on dataset published previously. As a result, 87.7% of the potential SOMs were correctly identified by our four models. In summary, four MMRS-based models were established, which can be used to predict the metabolism mediated by CYP3A4, 2D6, and 2C9 with high accuracy. PMID:27735849

  12. Novel Marmoset Cytochrome P450 2C19 in Livers Efficiently Metabolizes Human P450 2C9 and 2C19 Substrates, S-Warfarin, Tolbutamide, Flurbiprofen, and Omeprazole.

    PubMed

    Uehara, Shotaro; Uno, Yasuhiro; Inoue, Takashi; Kawano, Mirai; Shimizu, Makiko; Toda, Akiko; Utoh, Masahiro; Sasaki, Erika; Yamazaki, Hiroshi

    2015-10-01

    The common marmoset (Callithrix jacchus), a small New World monkey, has the potential for use in human drug development due to its evolutionary closeness to humans. Four novel cDNAs, encoding cytochrome P450 (P450) 2C18, 2C19, 2C58, and 2C76, were cloned from marmoset livers to characterize P450 2C molecular properties, including previously reported P450 2C8. The deduced amino acid sequence showed high sequence identities (>86%) with those of human P450 2Cs, except for marmoset P450 2C76, which has a low sequence identity (∼70%) with any human P450 2Cs. Phylogenetic analysis showed that marmoset P450 2Cs were more closely clustered with those of humans and macaques than other species investigated. Quantitative polymerase chain reaction analysis showed that all of the marmoset P450 2C mRNAs were predominantly expressed in liver as opposed to the other tissues tested. Marmoset P450 2C proteins were detected in liver by immunoblotting using antibodies against human P450 2Cs. Among marmoset P450 2Cs heterologously expressed in Escherichia coli, marmoset P450 2C19 efficiently catalyzed human P450 2C substrates, S-warfarin, diclofenac, tolbutamide, flurbiprofen, and omeprazole. Marmoset P450 2C19 had high Vmax and low Km values for S-warfarin 7-hydroxylation that were comparable to those in human liver microsomes, indicating warfarin stereoselectivity similar to findings in humans. Faster in vivo S-warfarin clearance than R-warfarin after intravenous administration of racemic warfarin (0.2 mg/kg) to marmosets was consistent with the in vitro kinetic parameters. These results indicated that marmoset P450 2C enzymes had functional characteristics similar to those of humans, and that P450 2C-dependent metabolic properties are likewise similar between marmosets and humans.

  13. African Lettuce (Launaea taraxacifolia) Displays Possible Anticancer Effects and Herb-Drug Interaction Potential by CYP1A2, CYP2C9, and CYP2C19 Inhibition.

    PubMed

    Thomford, Nicholas E; Mkhize, Buyisile; Dzobo, Kevin; Mpye, Keleabetswe; Rowe, Arielle; Parker, M Iqbal; Wonkam, Ambroise; Skelton, Michelle; September, Alison V; Dandara, Collet

    2016-09-01

    Medicinal plants are part of the healthcare systems worldwide, especially in low- and middle-income countries. African lettuce (Launaea taraxacifolia) is cultivated extensively in Africa, from Senegal in the west to Ethiopia and Tanzania in the east, and in Southern Africa. Potential anticancer effects of L. taraxacifolia have been suggested, but little is known about putative molecular mechanisms or potential for herb-drug interactions through inhibition or induction of drug-metabolizing enzymes. We investigated the effects of crude aqueous extracts of L. taraxacifolia on growth kinetics and cell cycle progression of the WHC01 esophageal cancer cells. Antiproliferative and apoptotic effects were evaluated using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay and flow cytometry, while examining, in parallel, the genes regulating apoptosis and cell cycle in this cell culture model. In addition, we tested the inhibitory and enzyme kinetic effects of the aqueous L. taraxacifolia using recombinant human CYP450 isozyme model systems (CYP1A2, CYP2C9, and CYP2C19). L. taraxacifolia exhibited a significant growth inhibitory effect on the WHC01 cancer cells. Most cell cycle genes were downregulated. Cell cycle analysis showed a G0-G1 cell cycle arrest in WHC01 cells in the presence of L. taraxacifolia extract, accompanied by morphological changes. L. taraxacifolia extract treatment resulted in downregulation of expression levels of CYP1A2 (p < 0.0005) and CYP2C19 (p < 0.003) by 50-70%. L. taraxacifolia extract caused reversible and time-dependent inhibition of the recombinant CYP1A2, CYP2C9, and CYP2C19. This study provides new insights on possible anticancer effects of L. taraxacifolia, a widely used medicinal plant in parts of Africa and across the world especially by patients with cancer. Further mechanistic studies expanding on these observations would be timely and contribute to the field of global precision medicine that requires

  14. Pharmacogenetics in American Indian Populations: Analysis of CYP2D6, CYP3A4, CYP3A5, and CYP2C9 in the Confederated Salish and Kootenai Tribes

    PubMed Central

    Fohner, Alison; Muzquiz, LeeAnna I.; Austin, Melissa A.; Gaedigk, Andrea; Gordon, Adam; Thornton, Timothy; Rieder, Mark J.; Pershouse, Mark A.; Putnam, Elizabeth A.; Howlett, Kevin; Beatty, Patrick; Thummel, Kenneth E.; Woodahl, Erica L.

    2014-01-01

    Objectives Cytochrome P450 enzymes play a dominant role in drug elimination and variation in these genes is a major source of interindividual differences in drug response. Little is known, however, about pharmacogenetic variation in American Indian and Alaska Native (AI/AN) populations. We have developed a partnership with the Confederated Salish and Kootenai Tribes (CSKT) in northwestern Montana to address this knowledge gap. Methods We resequenced CYP2D6 in 187 CSKT subjects and CYP3A4, CYP3A5, and CYP2C9 in 94 CSKT subjects. Results We identified 67 variants in CYP2D6, 15 in CYP3A4, 10 in CYP3A5, and 41 in CYP2C9. The most common CYP2D6 alleles were CYP2D6*4 and *41 (20.86 and 11.23%, respectively). CYP2D6*3, *5, *6, *9, *10, *17, *28, *33, *35, *49, *1xN, *2xN, and *4xN frequencies were less than 2%. CYP3A5*3, CYP3A4*1G, and *1B were detected with frequencies of 92.47, 26.81, and 2.20%, respectively. Allelic variation in CYP2C9 was low: CYP2C9*2 (5.17%) and *3 (2.69%). In general, allele frequencies in CYP2D6, CYP2C9 and CYP3A5 were similar to those observed in European Americans. There was, however, a marked divergence in CYP3A4 for the CYP3A4*1G allele. We also observed low levels of linkage between CYP3A4*1G and CYP3A5*1 in the CSKT. The combination of nonfunctional CYP3A5*3 and putative reduced function CYP3A4*1G alleles may predict diminished clearance of CYP3A substrates. Conclusions These results highlight the importance of conducting pharmacogenomic research in AI/AN populations and demonstrate that extrapolation from other populations is not appropriate. This information could help to optimize drug therapy for the CSKT population. PMID:23778323

  15. Effects of Panax notoginseng saponins on the activities of CYP1A2, CYP2C9, CYP2D6 and CYP3A4 in rats in vivo.

    PubMed

    Liu, Rui; Qin, Mengnan; Hang, Pengzhou; Liu, Yan; Zhang, Zhiren; Liu, Gaofeng

    2012-08-01

    The aim of this study was to assess the influence of the Panax notoginseng saponins (PNS) on the activities of the drug-metabolizing enzymes cytochrome P450 (CYP450) 1A2, 2 C9, 2D6 and 3A4 in rats. The activities of CYP1A2, 2 C9, 2D6 and 3A4 were measured using specific probe drugs. After pretreatment for 1 week with PNS or physiological saline (control group), probe drugs caffeine (10 mg/kg; CYP1A2 activity), tolbutamide (15 mg/kg; CYP2C9 activity), metoprolol (20 mg/kg; CYP2D6 activity) and dapsone (10 mg/kg; CYP3A4 activity) were administered to rats by intraperitoneal injection. The blood was then collected at different times for ultra performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) analysis. The data showed that PNS exhibited an induction effect on CYP1A2 by decreasing caffeine C(max) (36.3%, p < 0.01) and AUC(0-∞) (22.77%, p < 0.05) and increasing CL/F (27.03%, p < 0.05) compared with those of the control group. Western blot analysis was used to detect the effect of PNS on the protein level of CYP1A2, and the results showed that PNS could upregulate the protein expression of CYP1A2. However, no significant changes in CYP2C9, 2D6 or 3A4 activities were observed. In conclusion, the results indicate that PNS could induce CYP1A2, which may affect the disposition of medicines primarily dependent on the CYP1A2 pathway. Our work may be the basis of related herb-drug interactions in the clinic.

  16. Role of genetic polymorphisms of CYP1A1, CYP3A5, CYP2C9, CYP2D6, and PON1 in the modulation of DNA damage in workers occupationally exposed to organophosphate pesticides

    SciTech Connect

    Singh, Satyender; Kumar, Vivek; Vashisht, Kapil; Singh, Priyanka; Banerjee, Basu Dev; Rautela, Rajender Singh; Grover, Shyam Sunder; Rawat, Devendra Singh; Pasha, Syed Tazeen; Jain, Sudhir Kumar; Rai, Arvind

    2011-11-15

    Organophosphate pesticides (OPs) are primarily metabolized by several xenobiotic metabolizing enzymes (XMEs). Very few studies have explored genetic polymorphisms of XMEs and their association with DNA damage in pesticide-exposed workers. The present study was designed to determine the role of genetic polymorphisms of CYP1A1, CYP3A5, CYP2C9, CYP2D6, and PON1 in the modulation of DNA damage in workers occupationally exposed to OPs. We examined 284 subjects including 150 workers occupationally exposed to OPs and 134 normal healthy controls. The DNA damage was evaluated using the alkaline comet assay and genotyping was done using PCR-RFLP. The results revealed that the PONase activity toward paraoxonase and AChE activity was found significantly lowered in workers as compared to control subjects (p < 0.001). Workers showed significantly higher DNA damage compared to control subjects (14.37 {+-} 2.15 vs. 6.24 {+-} 1.37 tail% DNA, p < 0.001). Further, the workers with CYP2D6*3 PM and PON1 (QQ and MM) genotypes were found to have significantly higher DNA damage when compared to other genotypes (p < 0.05). In addition, significant increase in DNA damage was also observed in workers with concomitant presence of certain CYP2D6 and PON1 (Q192R and L55M) genotypes which need further extensive studies. In conclusion, the results indicate that the PON1 and CYP2D6 genotypes can modulate DNA damage elicited by some OPs possibly through gene-environment interactions. -- Highlights: Black-Right-Pointing-Pointer Role of CYP1A1, CYP3A5, CYP2C, CYP2D6 and PON1 genotypes on DNA damage. Black-Right-Pointing-Pointer Workers exposed to some OPs demonstrated increased DNA damage. Black-Right-Pointing-Pointer CYP2D6 *3 PM and PON1 (Q192R and L55M) genotypes are associated with DNA damage. Black-Right-Pointing-Pointer Concomitant presence of certain CYP2D6 and PON1 genotypes can increase DNA damage.

  17. Role of genetic polymorphisms of CYP1A1, CYP3A5, CYP2C9, CYP2D6, and PON1 in the modulation of DNA damage in workers occupationally exposed to organophosphate pesticides.

    PubMed

    Singh, Satyender; Kumar, Vivek; Vashisht, Kapil; Singh, Priyanka; Banerjee, Basu Dev; Rautela, Rajender Singh; Grover, Shyam Sunder; Rawat, Devendra Singh; Pasha, Syed Tazeen; Jain, Sudhir Kumar; Rai, Arvind

    2011-11-15

    Organophosphate pesticides (OPs) are primarily metabolized by several xenobiotic metabolizing enzymes (XMEs). Very few studies have explored genetic polymorphisms of XMEs and their association with DNA damage in pesticide-exposed workers. The present study was designed to determine the role of genetic polymorphisms of CYP1A1, CYP3A5, CYP2C9, CYP2D6, and PON1 in the modulation of DNA damage in workers occupationally exposed to OPs. We examined 284 subjects including 150 workers occupationally exposed to OPs and 134 normal healthy controls. The DNA damage was evaluated using the alkaline comet assay and genotyping was done using PCR-RFLP. The results revealed that the PONase activity toward paraoxonase and AChE activity was found significantly lowered in workers as compared to control subjects (p<0.001). Workers showed significantly higher DNA damage compared to control subjects (14.37±2.15 vs. 6.24±1.37 tail% DNA, p<0.001). Further, the workers with CYP2D6*3PM and PON1 (QQ and MM) genotypes were found to have significantly higher DNA damage when compared to other genotypes (p<0.05). In addition, significant increase in DNA damage was also observed in workers with concomitant presence of certain CYP2D6 and PON1 (Q192R and L55M) genotypes which need further extensive studies. In conclusion, the results indicate that the PON1 and CYP2D6 genotypes can modulate DNA damage elicited by some OPs possibly through gene-environment interactions.

  18. Effects of Radix Astragali and Radix Rehmanniae, the components of an anti-diabetic foot ulcer herbal formula, on metabolism of model CYP1A2, CYP2C9, CYP2D6, CYP2E1 and CYP3A4 probe substrates in pooled human liver microsomes and specific CYP isoforms.

    PubMed

    Or, Penelope M Y; Lam, Francis F Y; Kwan, Y W; Cho, C H; Lau, C P; Yu, H; Lin, G; Lau, Clara B S; Fung, K P; Leung, P C; Yeung, John H K

    2012-04-15

    The present study investigated the effects of Radix Astragali (RA) and Radix Rehmanniae (RR), the major components of an anti-diabetic foot ulcer herbal formula (NF3), on the metabolism of model probe substrates of human CYP isoforms, CYP1A2, CYP2C9, CYP2D6, CYP2E1 and CYP3A4, which are important in the metabolism of a variety of xenobiotics. The effects of RA or RR on human CYP1A2 (phenacetin O-deethylase), CYP2C9 (tolbutamide 4-hydroxylase), CYP2D6 (dextromethorphan O-demethylase), CYP2E1 (chlorzoxazone 6-hydroxylase) and CYP3A4 (testosterone 6β-hydroxylase) activities were investigated using pooled human liver microsomes. NF3 competitively inhibited activities of CYP2C9 (IC(50)=0.98mg/ml) and CYP3A4 (IC(50)=0.76mg/ml), with K(i) of 0.67 and 1.0mg/ml, respectively. With specific human CYP2C9 and CYP3A4 isoforms, NF3 competitively inhibited activities of CYP2C9 (IC(50)=0.86mg/ml) and CYP3A4 (IC(50)=0.88mg/ml), with K(i) of 0.57 and 1.6mg/ml, respectively. Studies on RA or RR individually showed that RR was more important in the metabolic interaction with the model CYP probe substrates. RR dose-dependently inhibited the testosterone 6β-hydroxylation (K(i)=0.33mg/ml) while RA showed only minimal metabolic interaction potential with the model CYP probe substrates studied. This study showed that RR and the NF3 formula are metabolized mainly by CYP2C9 and/or CYP3A4, but weakly by CYP1A2, CYP2D6 and CYP2E1. The relatively high K(i) values of NF3 (for CYP2C9 and CYP3A4 metabolism) and RR (for CYP3A4 metabolism) would suggest a low potential for NF3 to cause herb-drug interaction involving these CYP isoforms.

  19. CYP2C subfamily, primarily CYP2C9, catalyses the enantioselective demethylation of the endocrine disruptor pesticide methoxychlor in human liver microsomes: use of inhibitory monoclonal antibodies in P450 identification.

    PubMed

    Hu, Y; Krausz, K; Gelboin, H V; Kupfer, D

    2004-02-01

    1. The endocrine disruptor pesticide methoxychlor undergoes O-demethylation by mammalian liver microsomes forming chiral mono-phenolic (1,1,1-trichloro-2-(4-hydroxyphenyl)-2-(4-methoxyphenyl)ethane, i.e. mono-OH-M) and achiral bis-phenolic oestrogenic metabolites. Human liver microsomes (HLM) generated primarily the S-mono-OH-M. 2. Inhibitory monoclonal antibodies (MAb) identified those P450s catalysing the enantioselective O-demethylation of methoxychlor. In HLM, O-demethylation was inhibited by MAb anti-2C9 (30-40%), diminishing the per cent of S-mono-OH-M from about 80 to 55-60%. MAb anti-CYP1A2, 2A6, 2B6, 2C8, 2C19, 2D6 and 3A4 did not affect the demethylation rate in HLM. Nevertheless, MAb anti-CYP1A2 decreased the formation of R-mono-OH-M from 21-23 to 10-17%, indicating that CYP1A2 exhibits a role in generating the R-enantiomer. 3. Among cDNA-expressed human P450s (supersomes), CYP2C19 was the most active in demethylation, but in HLM, CYP2C19 appeared inactive (no inhibition by MAb anti-CYP2C19). There was a substantial difference in the per cent inhibition of demethylation by MAb anti-CYP2C9 and anti-rat CYP2C (MAb inhibiting all human CYP2C forms) and in altering the enantioselectivity, suggesting that demethylation by combined CYP2C8, 2C18 and 2C19 was significant (20-30%). 4. Polymorphism of methoxychlor demethylation was examined with supersomes and HLM-expressing CYP2C9 allelic variants. CYP2C9*1 and 2C9*2 were highly active; however, CYP2C9*3 appeared inactive.

  20. Metabolism of risperidone to 9-hydroxyrisperidone by human cytochromes P450 2D6 and 3A4.

    PubMed

    Fang, J; Bourin, M; Baker, G B

    1999-02-01

    Risperidone is a relatively new antipsychotic drug that has been reported to improve both the positive and the negative symptoms of schizophrenia and produces relatively few extrapyramidal side effects at low doses. Formation of 9-hydroxyrisperidone, an active metabolite, is the most important metabolic pathway of risperidone in human. In the present study, in vitro metabolism of risperidone (100 microM) was investigated using the recombinant human cytochrome P450 (CYP) enzymes CYP1A1, CYP1A2, CYP2C8, CYP2C9-arg144, CYP2C9-cys144, CYP2C19, CYP2D6, CYP3A4 and CYP3A5 supplemented with an NADPH-generating system. 9-Hydroxyrisperidone was determined by a new HPLC method with an Hypersil CN column and a UV detector. Of these enzymes, CYPs 2D6, 3A4 and 3A5 were found to be the ones capable of metabolising risperidone to 9-hydroxyrisperidone, with activities of 7.5, 0.4 and 0.2 pmol pmol(-1) CYP min(-1), respectively. A correlation study using a panel of human liver microsomes showed that the formation of 9-hydroxyrisperidone is highly correlated with CYP2D6 and 3A activities. Thus, both CYP2D6 and 3A4 are involved in the 9-hydroxylation of risperidone at the concentration of risperidone used in this study. This observation is confirmed by the findings that both quinidine (inhibitor of CYP2D6) and ketoconazole (inhibitor of CYP3A4) can inhibit the formation of 9-hydroxyrisperidone. Furthermore, inducers of CYP can significantly increase the formation of 9-hydroxyrisperidone in rat. The formation of 9-hydroxyrisperidone is highly correlated with testosterone 6beta-hydroxylase activities, suggesting that inducible CYP3A contributes significantly to the metabolism of risperidone in rat.

  1. Similar substrate specificity of cynomolgus monkey cytochrome P450 2C19 to reported human P450 2C counterpart enzymes by evaluation of 89 drug clearances.

    PubMed

    Hosaka, Shinya; Murayama, Norie; Satsukawa, Masahiro; Uehara, Shotaro; Shimizu, Makiko; Iwasaki, Kazuhide; Iwano, Shunsuke; Uno, Yasuhiro; Yamazaki, Hiroshi

    2015-12-01

    Cynomolgus monkeys are used widely in preclinical studies as non-human primate species. The amino acid sequence of cynomolgus monkey cytochrome P450 (P450 or CYP) 2C19 is reportedly highly correlated to that of human CYP2C19 (92%) and CYP2C9 (93%). In the present study, 89 commercially available compounds were screened to find potential substrates for cynomolgus monkey CYP2C19. Of 89 drugs, 34 were metabolically depleted by cynomolgus monkey CYP2C19 with relatively high rates. Among them, 30 compounds have been reported as substrates or inhibitors of, either or both, human CYP2C19 and CYP2C9. Several compounds, including loratadine, showed high selectivity to cynomolgus monkey CYP2C19, and all of these have been reported as human CYP2C19 and/or CYP2C9 substrates. In addition, cynomolgus monkey CYP2C19 formed the same loratadine metabolite as human CYP2C19, descarboethoxyloratadine. These results suggest that cynomolgus monkey CYP2C19 is generally similar to human CYP2C19 and CYP2C9 in its substrate recognition functionality.

  2. Evaluation of six proton pump inhibitors as inhibitors of various human cytochromes P450: focus on cytochrome P450 2C19.

    PubMed

    Zvyaga, Tatyana; Chang, Shu-Ying; Chen, Cliff; Yang, Zheng; Vuppugalla, Ragini; Hurley, Jeremy; Thorndike, Denise; Wagner, Andrew; Chimalakonda, Anjaneya; Rodrigues, A David

    2012-09-01

    Six proton pump inhibitors (PPIs), omeprazole, lansoprazole, esomeprazole, dexlansoprazole, pantoprazole, and rabeprazole, were shown to be weak inhibitors of cytochromes P450 (CYP3A4, -2B6, -2D6, -2C9, -2C8, and -1A2) in human liver microsomes. In most cases, IC₅₀ values were greater than 40 μM, except for dexlansoprazole and lansoprazole with CYP1A2 (IC₅₀ = ∼8 μM) and esomeprazole with CYP2C8 (IC₅₀ = 31 μM). With the exception of CYP2C19 inhibition by omeprazole and esomeprazole (IC₅₀ ratio, 2.5 to 5.9), there was no evidence for a marked time-dependent shift in IC₅₀ (IC₅₀ ratio, ≤ 2) after a 30-min preincubation with NADPH. In the absence of preincubation, lansoprazole (IC₅₀ = 0.73 μM) and esomeprazole (IC₅₀ = 3.7 μM) were the most potent CYP2C19 inhibitors, followed by dexlansoprazole and omeprazole (IC₅₀ = ∼7.0 μM). Rabeprazole and pantoprazole (IC₅₀ = ≥ 25 μM) were the weakest. A similar ranking was obtained with recombinant CYP2C19. Despite the IC₅₀ ranking, after consideration of plasma levels (static and dynamic), protein binding, and metabolism-dependent inhibition, it is concluded that omeprazole and esomeprazole are the most potent CYP2C19 inhibitors. This was confirmed after the incubation of the individual PPIs with human primary hepatocytes (in the presence of human serum) and by monitoring their impact on diazepam N-demethylase activity at a low concentration of diazepam (2 μM). Data described herein are consistent with reports that PPIs are mostly weak inhibitors of cytochromes P450 in vivo. However, two members of the PPI class (esomeprazole and omeprazole) are more likely to serve as clinically relevant inhibitors of CYP2C19.

  3. Interethnic variation of CYP2C19 alleles, 'predicted' phenotypes and 'measured' metabolic phenotypes across world populations.

    PubMed

    Fricke-Galindo, I; Céspedes-Garro, C; Rodrigues-Soares, F; Naranjo, M E G; Delgado, Á; de Andrés, F; López-López, M; Peñas-Lledó, E; LLerena, A

    2016-04-01

    The present study evaluates the worldwide frequency distribution of CYP2C19 alleles and CYP2C19 metabolic phenotypes ('predicted' from genotypes and 'measured' with a probe drug) among healthy volunteers from different ethnic groups and geographic regions, as well as the relationship between the 'predicted' and 'measured' CYP2C19 metabolic phenotypes. A total of 52 181 healthy volunteers were studied within 138 selected original research papers. CYP2C19*17 was 42- and 24-fold more frequent in Mediterranean-South Europeans and Middle Easterns than in East Asians (P<0.001, in both cases). Contrarily, CYP2C19*2 and CYP2C19*3 alleles were more frequent in East Asians (30.26% and 6.89%, respectively), and even a twofold higher frequency of these alleles was found in Native populations from Oceania (61.30% and 14.42%, respectively; P<0.001, in all cases), which may be a consequence of genetic drift process in the Pacific Islands. Regarding CYP2C19 metabolic phenotype, poor metabolizers (PMs) were more frequent among Asians than in Europeans, contrarily to the phenomenon reported for CYP2D6. A correlation has been found between the frequencies of CYP2C19 poor metabolism 'predicted' from CYP2C19 genotypes (gPMs) and the poor metabolic phenotype 'measured' with a probe drug (mPMs) when subjects are either classified by ethnicity (r=0.94, P<0.001) or geographic region (r=0.99, P=0.002). Nevertheless, further research is needed in African and Asian populations, which are under-represented, and additional CYP2C19 variants and the 'measured' phenotype should be studied. PMID:26503820

  4. Interethnic variation of CYP2C19 alleles, 'predicted' phenotypes and 'measured' metabolic phenotypes across world populations.

    PubMed

    Fricke-Galindo, I; Céspedes-Garro, C; Rodrigues-Soares, F; Naranjo, M E G; Delgado, Á; de Andrés, F; López-López, M; Peñas-Lledó, E; LLerena, A

    2016-04-01

    The present study evaluates the worldwide frequency distribution of CYP2C19 alleles and CYP2C19 metabolic phenotypes ('predicted' from genotypes and 'measured' with a probe drug) among healthy volunteers from different ethnic groups and geographic regions, as well as the relationship between the 'predicted' and 'measured' CYP2C19 metabolic phenotypes. A total of 52 181 healthy volunteers were studied within 138 selected original research papers. CYP2C19*17 was 42- and 24-fold more frequent in Mediterranean-South Europeans and Middle Easterns than in East Asians (P<0.001, in both cases). Contrarily, CYP2C19*2 and CYP2C19*3 alleles were more frequent in East Asians (30.26% and 6.89%, respectively), and even a twofold higher frequency of these alleles was found in Native populations from Oceania (61.30% and 14.42%, respectively; P<0.001, in all cases), which may be a consequence of genetic drift process in the Pacific Islands. Regarding CYP2C19 metabolic phenotype, poor metabolizers (PMs) were more frequent among Asians than in Europeans, contrarily to the phenomenon reported for CYP2D6. A correlation has been found between the frequencies of CYP2C19 poor metabolism 'predicted' from CYP2C19 genotypes (gPMs) and the poor metabolic phenotype 'measured' with a probe drug (mPMs) when subjects are either classified by ethnicity (r=0.94, P<0.001) or geographic region (r=0.99, P=0.002). Nevertheless, further research is needed in African and Asian populations, which are under-represented, and additional CYP2C19 variants and the 'measured' phenotype should be studied.

  5. Comprehensive Evaluation for Substrate Selectivity of Cynomolgus Monkey Cytochrome P450 2C9, a New Efavirenz Oxidase.

    PubMed

    Hosaka, Shinya; Murayama, Norie; Satsukawa, Masahiro; Uehara, Shotaro; Shimizu, Makiko; Iwasaki, Kazuhide; Iwano, Shunsuke; Uno, Yasuhiro; Yamazaki, Hiroshi

    2015-07-01

    Cynomolgus monkeys are widely used as primate models in preclinical studies, because of their evolutionary closeness to humans. In humans, the cytochrome P450 (P450) 2C enzymes are important drug-metabolizing enzymes and highly expressed in livers. The CYP2C enzymes, including CYP2C9, are also expressed abundantly in cynomolgus monkey liver and metabolize some endogenous and exogenous substances like testosterone, S-mephenytoin, and diclofenac. However, comprehensive evaluation regarding substrate specificity of monkey CYP2C9 has not been conducted. In the present study, 89 commercially available drugs were examined to find potential monkey CYP2C9 substrates. Among the compounds screened, 20 drugs were metabolized by monkey CYP2C9 at a relatively high rates. Seventeen of these compounds were substrates or inhibitors of human CYP2C9 or CYP2C19, whereas three drugs were not, indicating that substrate specificity of monkey CYP2C9 resembled those of human CYP2C9 or CYP2C19, with some differences in substrate specificities. Although efavirenz is known as a marker substrate for human CYP2B6, efavirenz was not oxidized by CYP2B6 but by CYP2C9 in monkeys. Liquid chromatography-mass spectrometry analysis revealed that monkey CYP2C9 and human CYP2B6 formed the same mono- and di-oxidized metabolites of efavirenz at 8 and 14 positions. These results suggest that the efavirenz 8-oxidation could be one of the selective markers for cynomolgus monkey CYP2C9 among the major three CYP2C enzymes tested. Therefore, monkey CYP2C9 has the possibility of contributing to limited specific differences in drug oxidative metabolism between cynomolgus monkeys and humans. PMID:25948712

  6. Comprehensive Evaluation for Substrate Selectivity of Cynomolgus Monkey Cytochrome P450 2C9, a New Efavirenz Oxidase.

    PubMed

    Hosaka, Shinya; Murayama, Norie; Satsukawa, Masahiro; Uehara, Shotaro; Shimizu, Makiko; Iwasaki, Kazuhide; Iwano, Shunsuke; Uno, Yasuhiro; Yamazaki, Hiroshi

    2015-07-01

    Cynomolgus monkeys are widely used as primate models in preclinical studies, because of their evolutionary closeness to humans. In humans, the cytochrome P450 (P450) 2C enzymes are important drug-metabolizing enzymes and highly expressed in livers. The CYP2C enzymes, including CYP2C9, are also expressed abundantly in cynomolgus monkey liver and metabolize some endogenous and exogenous substances like testosterone, S-mephenytoin, and diclofenac. However, comprehensive evaluation regarding substrate specificity of monkey CYP2C9 has not been conducted. In the present study, 89 commercially available drugs were examined to find potential monkey CYP2C9 substrates. Among the compounds screened, 20 drugs were metabolized by monkey CYP2C9 at a relatively high rates. Seventeen of these compounds were substrates or inhibitors of human CYP2C9 or CYP2C19, whereas three drugs were not, indicating that substrate specificity of monkey CYP2C9 resembled those of human CYP2C9 or CYP2C19, with some differences in substrate specificities. Although efavirenz is known as a marker substrate for human CYP2B6, efavirenz was not oxidized by CYP2B6 but by CYP2C9 in monkeys. Liquid chromatography-mass spectrometry analysis revealed that monkey CYP2C9 and human CYP2B6 formed the same mono- and di-oxidized metabolites of efavirenz at 8 and 14 positions. These results suggest that the efavirenz 8-oxidation could be one of the selective markers for cynomolgus monkey CYP2C9 among the major three CYP2C enzymes tested. Therefore, monkey CYP2C9 has the possibility of contributing to limited specific differences in drug oxidative metabolism between cynomolgus monkeys and humans.

  7. The role of CYP2C9 genetic polymorphism in carvedilol O-desmethylation in vitro.

    PubMed

    Pan, Pei-Pei; Weng, Qing-Hua; Zhou, Chen-Jian; Wei, Yan-Li; Wang, Li; Dai, Da-Peng; Cai, Jian-Ping; Hu, Guo-Xin

    2016-02-01

    We aimed at investigating the role of CYP2C9 in carvedilol O-desmethylation and identifying the effect of 35 CYP2C9 allelic variants we found in Chinese Han population on the in vitro metabolism of carvedilol. Recombinant CYP2C9 and CYP2D6 microsomes of the wild type were used to test and verify the enzymes involved in carvedilol O-desmethylation. Recombinant CYP2C9 microsomes of distinguished genotypes were used to characterize the corresponding enzyme activity toward carvedilol. 2-100 μM carvedilol was incubated for 30 min at 37 °C. The products were detected using high-performance liquid chromatography. CYP2C9 plays a certain role in carvedilol metabolism. Compared with wild-type CYP2C9*1, the intrinsic clearance (V max/K m) values of all variants toward carvedilol O-desmethylation were significantly altered. The variants exhibited significantly decreased values (from 30 to 99.8 %) due to increased K m and/or decreased V max values. We conclude that recombinant system could be used to investigate the enzymes involved in drug metabolism and these findings complement the database where CYP2C9 polymorphism interacts with biotransformation of exogenous substances like drugs and toxins.

  8. Monkey liver cytochrome P450 2C19 is involved in R- and S-warfarin 7-hydroxylation.

    PubMed

    Hosoi, Yoshio; Uno, Yasuhiro; Murayama, Norie; Fujino, Hideki; Shukuya, Mitsunori; Iwasaki, Kazuhide; Shimizu, Makiko; Utoh, Masahiro; Yamazaki, Hiroshi

    2012-12-15

    Cynomolgus monkeys are widely used as primate models in preclinical studies. However, some differences are occasionally seen between monkeys and humans in the activities of cytochrome P450 enzymes. R- and S-warfarin are model substrates for stereoselective oxidation in humans. In this current research, the activities of monkey liver microsomes and 14 recombinantly expressed monkey cytochrome P450 enzymes were analyzed with respect to R- and S-warfarin 6- and 7-hydroxylation. Monkey liver microsomes efficiently mediated both R- and S-warfarin 7-hydroxylation, in contrast to human liver microsomes, which preferentially catalyzed S-warfarin 7-hydroxylation. R-Warfarin 7-hydroxylation activities in monkey liver microsomes were not inhibited by α-naphthoflavone or ketoconazole, and were roughly correlated with P450 2C19 levels and flurbiprofen 4-hydroxylation activities in microsomes from 20 monkey livers. In contrast, S-warfarin 7-hydroxylation activities were not correlated with the four marker drug oxidation activities used. Among the 14 recombinantly expressed monkey P450 enzymes tested, P450 2C19 had the highest activities for R- and S-warfarin 7-hydroxylations. Monkey P450 3A4 and 3A5 slowly mediated R- and S-warfarin 6-hydroxylations. Kinetic analysis revealed that monkey P450 2C19 had high V(max) and low K(m) values for R-warfarin 7-hydroxylation, comparable to those for monkey liver microsomes. Monkey P450 2C19 also mediated S-warfarin 7-hydroxylation with V(max) and V(max)/K(m) values comparable to those for recombinant human P450 2C9. R-warfarin could dock favorably into monkey P450 2C19 modeled. These results collectively suggest high activities for monkey liver P450 2C19 toward R- and S-warfarin 6- and 7-hydroxylation in contrast to the saturation kinetics of human P450 2C9-mediated S-warfarin 7-hydroxylation.

  9. Regulation of Human CYP2C9 Expression by Electrophilic Stress Involves Activator Protein 1 Activation and DNA Looping

    PubMed Central

    Makia, Ngome L.; Surapureddi, Sailesh; Monostory, Katalin; Prough, Russell A.

    2014-01-01

    Cytochrome P450 (CYP)2C9 and CYP2C19 are important human enzymes that metabolize therapeutic drugs, environmental chemicals, and physiologically important endogenous compounds. Initial studies using primary human hepatocytes showed induction of both the CYP2C9 and CYP2C19 genes by tert-butylhydroquinone (tBHQ). As a pro-oxidant, tBHQ regulates the expression of cytoprotective genes by activation of redox-sensing transcription factors, such as the nuclear factor E2-related factor 2 (Nrf2) and members of the activator protein 1 (AP-1) family of proteins. The promoter region of CYP2C9 contains two putative AP-1 sites (TGAGTCA) at positions −2201 and −1930, which are also highly conserved in CYP2C19. The CYP2C9 promoter is activated by ectopic expression of cFos and JunD, whereas Nrf2 had no effect. Using specific kinase inhibitors for mitogen-activated protein kinase, we showed that extracellular signal-regulated kinase and Jun N-terminal kinase are essential for tBHQ-induced expression of CYP2C9. Electrophoretic mobility shift assays demonstrate that cFos distinctly interacts with the distal AP-1 site and JunD with the proximal site. Because cFos regulates target genes as heterodimers with Jun proteins, we hypothesized that DNA looping might be required to bring the distal and proximal AP-1 sites together to activate the CYP2C9 promoter. Chromosome conformation capture analyses confirmed the formation of a DNA loop in the CYP2C9 promoter, possibly allowing interaction between cFos at the distal site and JunD at the proximal site to activate CYP2C9 transcription in response to electrophiles. These results indicate that oxidative stress generated by exposure to electrophilic xenobiotics and metabolites induces the expression of CYP2C9 and CYP2C19 in human hepatocytes. PMID:24830941

  10. The CYP2C19 Intron 2 Branch Point SNP is the Ancestral Polymorphism Contributing to the Poor Metabolizer Phenotype in Livers with CYP2C19*35 and CYP2C19*2 Alleles

    PubMed Central

    Chaudhry, Amarjit S.; Prasad, Bhagwat; Shirasaka, Yoshiyuki; Fohner, Alison; Finkelstein, David; Fan, Yiping; Wang, Shuoguo; Wu, Gang; Aklillu, Eleni; Sim, Sarah C.; Thummel, Kenneth E.

    2015-01-01

    CYP2C19 rs12769205 alters an intron 2 branch point adenine leading to an alternative mRNA in human liver with complete inclusion of intron 2 (exon 2B). rs12769205 changes the mRNA reading frame, introduces 87 amino acids, and leads to a premature stop codon. The 1000 Genomes project (http://browser.1000genomes.org/index.html) indicated rs12769205 is in linkage disequilibrium with rs4244285 on CYP2C19*2, but found alone on CYP2C19*35 in Blacks. Minigenes containing rs12769205 transfected into HepG2 cells demonstrated this single nucleotide polymorphism (SNP) alone leads to exon 2B and decreases CYP2C19 canonical mRNA. A residual amount of CYP2C19 protein was detectable by quantitative proteomics with tandem mass spectrometry in CYP2C19*2/*2 and *1/*35 liver microsomes with an exon 2 probe. However, an exon 4 probe, downstream from rs12769205, but upstream of rs4244285, failed to detect CYP2C19 protein in livers homozygous for rs12769205, demonstrating rs12769205 alone can lead to complete loss of CYP2C19 protein. CYP2C19 genotypes and mephenytoin phenotype were compared in 104 Ethiopians. Poor metabolism of mephenytoin was seen in persons homozygous for both rs12769205 and rs4244285 (CYP2C19*2/*2), but with little effect on mephenytoin disposition of CYP2C19*1/*2, CYP2C19*1/*3, or CYP2C19*1/*35 heterozygous alleles. Extended haplotype homozygosity tests of the HapMap Yorubans (YRI) showed both haplotypes carrying rs12769205 (CYP2C19*35 and CYP2C19*2) are under significant natural selection, with CYP2C19*35 having a higher relative extended haplotype homozygosity score. The phylogenetic tree of the YRI CYP2C19 haplotypes revealed rs12769205 arose first on CYP2C19*35 and that rs4244285 was added later, creating CYP2C19*2. In conclusion, rs12769205 is the ancestral polymorphism leading to aberrant splicing of CYP2C19*35 and CYP2C19*2 alleles in liver. PMID:26021325

  11. CYP2D6*36 gene arrangements within the cyp2d6 locus: association of CYP2D6*36 with poor metabolizer status.

    PubMed

    Gaedigk, Andrea; Bradford, L Dianne; Alander, Sarah W; Leeder, J Steven

    2006-04-01

    Unexplained cases of CYP2D6 genotype/phenotype discordance continue to be discovered. In previous studies, several African Americans with a poor metabolizer phenotype carried the reduced function CYP2D6*10 allele in combination with a nonfunctional allele. We pursued the possibility that these alleles harbor either a known sequence variation (i.e., CYP2D6*36 carrying a gene conversion in exon 9 along the CYP2D6*10-defining 100C>T single-nucleotide polymorphism) or novel sequences variation(s). Discordant cases were evaluated by long-range polymerase chain reaction (PCR) to test for gene rearrangement events, and a 6.6-kilobase pair PCR product encompassing the CYP2D6 gene was cloned and entirely sequenced. Thereafter, allele frequencies were determined in different study populations comprising whites, African Americans, and Asians. Analyses covering the CYP2D7 to 2D6 gene region established that CYP2D6*36 did not only exist as a gene duplication (CYP2D6*36x2) or in tandem with *10 (CYP2D6*36+*10), as previously reported, but also by itself. This "single" CYP2D6*36 allele was found in nine African Americans and one Asian, but was absent in the whites tested. Ultimately, the presence of CYP2D6*36 resolved genotype/phenotype discordance in three cases. We also discovered an exon 9 conversion-positive CYP2D6*4 gene in a duplication arrangement (CYP2D6*4Nx2) and a CYP2D6*4 allele lacking 100C>T (CYP2D6*4M) in two white subjects. The discovery of an allele that carries only one CYP2D6*36 gene copy provides unequivocal evidence that both CYP2D6*36 and *36x2 are associated with a poor metabolizer phenotype. Given a combined frequency of between 0.5 and 3% in African Americans and Asians, genotyping for CYP2D6*36 should improve the accuracy of genotype-based phenotype prediction in these populations.

  12. Inhibition of human cytochrome P450 2D6 (CYP2D6) by methadone.

    PubMed Central

    Wu, D; Otton, S V; Sproule, B A; Busto, U; Inaba, T; Kalow, W; Sellers, E M

    1993-01-01

    1. In microsomes prepared from three human livers, methadone competitively inhibited the O-demethylation of dextromethorphan, a marker substrate for CYP2D6. The apparent Ki value of methadone ranged from 2.5 to 5 microM. 2. Two hundred and fifty-two (252) white Caucasians, including 210 unrelated healthy volunteers and 42 opiate abusers undergoing treatment with methadone were phenotyped using dextromethorphan as the marker drug. Although the frequency of poor metabolizers was similar in both groups, the extensive metabolizers among the opiate abusers tended to have higher O-demethylation metabolic ratios and to excrete less of the dose as dextromethorphan metabolites than control extensive metabolizer subjects. These data suggest inhibition of CYP2D6 by methadone in vivo as well. 3. Because methadone is widely used in the treatment of opiate abuse, inhibition of CYP2D6 activity in these patients might contribute to exaggerated response or unexpected toxicity from drugs that are substrates of this enzyme. PMID:8448065

  13. Allele frequency distribution of CYP2C9 2 and CYP2C9 3 polymorphisms in six Mexican populations.

    PubMed

    Castelán-Martínez, Osvaldo D; Hoyo-Vadillo, Carlos; Sandoval-García, Emmanuel; Sandoval-Ramírez, Lucila; González-Ibarra, Miriam; Solano-Solano, Gloria; Gómez-Díaz, Rita A; Parra, Esteban J; Cruz, Miguel; Valladares-Salgado, Adán

    2013-07-10

    Allele frequency differences of functional CYP2C9 polymorphisms are responsible for some of the variation in drug response observed in human populations. The most relevant CYP2C9 functional variants are CYP2C9*2 (rs1799853) and CYP2C9 3 (rs1057910). These polymorphisms show variation in allele frequencies among different population groups. The present study aimed to analyze these polymorphisms in 947 Mexican-Mestizo from Mexico City and 483 individuals from five indigenous Mexican populations: Nahua, Teenek, Tarahumara, Purepecha and Huichol. The CYP2C9*2 allele frequencies in the Mestizo, Nahua and Teenek populations were 0.051, 0.007 and 0.005, respectively. As for CYP2C9 3, the allelic frequencies in the Mestizo, Nahua and Teenek populations were 0.04, 0.005 and 0.005, respectively. The CYP2C9 2 and CYP2C9 3 alleles were not observed in the Tarahumara, Purepecha and Huichol populations. These findings are in agreement with previous studies reporting very low allele frequencies for these polymorphisms in American Indigenous populations.

  14. Future Trends in the Pharmacogenomics of Brain Disorders and Dementia: Influence of APOE and CYP2D6 Variants

    PubMed Central

    Cacabelos, Ramón; Fernández-Novoa, Lucía; Martínez-Bouza, Rocío; McKay, Adam; Carril, Juan C.; Lombardi, Valter; Corzo, Lola; Carrera, Iván; Tellado, Iván; Nebril, Laura; Alcaraz, Margarita; Rodríguez, Susana; Casas, Ángela; Couceiro, Verónica; Álvarez, Antón

    2010-01-01

    About 80% of functional genes in the human genome are expressed in the brain and over 1,200 different genes have been associated with the pathogenesis of CNS disorders and dementia. Pharmacogenetic studies of psychotropic drug response have focused on determining the relationship between variations in specific candidate genes and the positive and adverse effects of drug treatment. Approximately, 18% of neuroleptics are substrates of CYP1A2 enzymes, 40% of CYP2D6, and 23% of CYP3A4; 24% of antidepressants are substrates of CYP1A2 enzymes, 5% of CYP2B6, 38% of CYP2C19, 85% of CYP2D6, and 38% of CYP3A4; 7% of benzodiazepines are substrates of CYP2C19 enzymes, 20% of CYP2D6, and 95% of CYP3A4. 10-20% of Western populations are defective in genes of the CYP superfamily; and the pharmacogenomic response of psychotropic drugs also depends on genetic variants associated with dementia. Prospective studies with anti-dementia drugs or with multifactorial strategies have revealed that the therapeutic response to conventional drugs in Alzheimer’s disease is genotype-specific. The disease-modifying effects (cognitive performance, biomarker modification) of therapeutic intervention are APOE-dependent, with APOE-4 carriers acting as the worst responders (APOE-3/3 > APOE-3/4 > APOE-4/4). APOE-CYP2D6 interactions also influence the therapeutic outcome in patients with dementia.

  15. Omeprazole-induced acute interstitial nephritis is not related to CYP2C19 genotype or CYP2C19 phenotype

    PubMed Central

    Helsby, Nuala A; Lo, Wing-Yee; Simpson, Ian J; Voss, David M; Logan, Kaye E; Searle, Martin; Schollum, John B W; de Zoysa, Janak R

    2010-01-01

    AIM Omeprazole-induced acute interstitial nephritis (OIAIN) is a rare adverse event. It is unknown if this is an idiosyncratic immune mediated reaction or if it relates to direct drug toxicity. Individuals who are homozygous for the variant alleles of CYP2C19 are poor metabolizers of omeprazole and have a greater exposure to the drug. The aim of this study was to determine the prevalence of the CYP2C19 poor metabolizer genotype and phenotype in patients with OIAIN. METHODS Twenty patients were genotyped for the CYP2C19 variant alleles (*2, 681G>A and *3, 636G>A) by RFLP-PCR analysis and eighteen phenotyped for CYP2C19 metabolizer status. RESULTS The frequency of the CYP2C19*2 allelic variant was 12.5%, no *3 allelic variants were detected and no patient was a homozygous variant genotype. This was not different from the expected frequency. 33% of subjects were phenotypically CYP2C19 poor metabolizers. CONCLUSIONS There was discordance between CYP2C19 genotype and phenotype. However, up to 45% of healthy elderly subjects have a poor metabolizer phenotype. Thus neither CYP2C19 poor metabolizer genotype nor phenotype is a risk factor for OIAIN. PMID:20573087

  16. Genotype and allele frequency of CYP2C19*17 in a healthy Iranian population

    PubMed Central

    Payan, Maryam; Tajik, Nader; Rouini, Mohammad Reza; Ghahremani, Mohammad Hossein

    2015-01-01

    Background: Cytochrome P450 2C19 (CYP2C19) is important in metabolism of wide range of drugs. CYP2C19*17 is a novel variant allele which increases gene transcription and therefore results in ultra-rapid metabolizer phenotype (URM). Distribution of this variant allele has not been well studied worldwide. The aim of present study was to investigate allele and genotype frequencies of CYP2C19*17 in a healthy Iranian population and compare them with other ethnic groups. Methods: One hundred eighty healthy unrelated Iranian volunteer took part in this study and were genotyped for CYP2C19 *2, *3, *17 (-3402) by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and CYP2C19*17 (-806) by a nested-PCR assays. The distribution of CYP2C19*17 polymorphism in Iranian population was then compared with other ethnic groups. Results: The CYP2C19*17 allele frequency was 21.6% in Iranian population. Among studied subjects 5.5% were homozygous for CYP2C19*17 and phenotyped as ultra-rapid metabolizers; 28.8% were genotyped as CYP2C19*1*17 (extensive metabolizers) and 3.3% as CYP2C19*2*17 (intermediate metabolizers). Conclusion: The CYP2C19*17 genetic distribution in Iranian population is similar to Middle East or European countries. The high frequency of CYP2C19*17 in Iranian population highlights the importance of this new variant allele in metabolism of CYP2C19 substrates. Thus, future association studies are required to reveal clinical consequence of this genetic polymorphism in carrier individuals. PMID:26793660

  17. Functional characterization of CYP2D6 enhancer polymorphisms

    PubMed Central

    Wang, Danxin; Papp, Audrey C.; Sun, Xiaochun

    2015-01-01

    CYP2D6 metabolizes nearly 25% of clinically used drugs. Genetic polymorphisms cause large inter-individual variability in CYP2D6 enzyme activity and are currently used as biomarker to predict CYP2D6 metabolizer phenotype. Previously, we had identified a region 115 kb downstream of CYP2D6 as enhancer for CYP2D6, containing two completely linked single nucleotide polymorphisms (SNPs), rs133333 and rs5758550, associated with enhanced transcription. However, the enhancer effect on CYP2D6 expression, and the causative variant, remained to be ascertained. To characterize the CYP2D6 enhancer element, we applied chromatin conformation capture combined with the next-generation sequencing (4C assays) and chromatin immunoprecipitation with P300 antibody, in HepG2 and human primary culture hepatocytes. The results confirmed the role of the previously identified enhancer region in CYP2D6 expression, expanding the number of candidate variants to three highly linked SNPs (rs133333, rs5758550 and rs4822082). Among these, only rs5758550 demonstrated regulating enhancer activity in a reporter gene assay. Use of clustered regularly interspaced short palindromic repeats mediated genome editing in HepG2 cells targeting suspected enhancer regions decreased CYP2D6 mRNA expression by 70%, only upon deletion of the rs5758550 region. These results demonstrate robust effects of both the enhancer element and SNP rs5758550 on CYP2D6 expression, supporting consideration of rs5758550 for CYP2D6 genotyping panels to yield more accurate phenotype prediction. PMID:25381333

  18. High-throughput screening assays for the assessment of CYP2C9*1, CYP2C9*2, and CYP2C9*3 metabolism using fluorogenic Vivid substrates.

    PubMed

    Marks, Bryan D; Thompson, David V; Goossens, Tony A; Trubetskoy, Olga V

    2004-08-01

    CYP2C9 is a genetically polymorphic human cytochrome P450 isozyme involved in the oxidative metabolism of many drugs, including nonsteroidal anti-inflammatory compounds. Individuals genotyped heterozygous or homozygous for CYP2C9 allelic variants have demonstrated altered metabolism of some drugs primarily metabolized by CYP2C9. The ability to expand screening of CYP2C9 allelic variants to a larger set of drugs and pharmaceutical agents would contribute to a better understanding of the significance of CYP2C9 polymorphisms in the population and to predictions of possible outcomes. The authors report the development of an in vitro fluorescence-based assay employing recombinant CYP2C9 variants (CYP2C9*1, CYP2C9*2, and CYP2C9*3) and fluorogenic Vivid(R) CYP2C9 substrates to explore the effects of CYP2C9 polymorphisms on drug metabolism, using drugs primarily metabolized by CYP2C9. Several chemically diverse fluorogenic substrates (Vivid(R) CYP2C9 blue, green, and red substrates) were used as prototypic probes to obtain in vitro CYP2C9 metabolic rates and kinetic parameters, such as apparent K(m), V(max), and V(max)/K(m) ratios for each allelic variant. In addition, a diverse panel of drugs was screened as assay modifiers with CYP2C9*1, CYP2C9*2, CYP2C9*3, and the fluorogenic Vivid(R) CYP2C9 substrates. The inhibitory potential of this large group of chemically diverse drugs and compounds has been assessed on the basis of their ability to compete with Vivid(R) CYP2C9 substrates in fluorescent reporter assays, thus providing a sensitive and quick assessment of polymorphism-dependent changes in CYP2C9 metabolism.

  19. Estrogen-Induced Cholestasis Leads to Repressed CYP2D6 Expression in CYP2D6-Humanized Mice

    PubMed Central

    Pan, Xian

    2015-01-01

    Cholestasis activates bile acid receptor farnesoid X receptor (FXR) and subsequently enhances hepatic expression of small heterodimer partner (SHP). We previously demonstrated that SHP represses the transactivation of cytochrome P450 2D6 (CYP2D6) promoter by hepatocyte nuclear factor (HNF) 4α. In this study, we investigated the effects of estrogen-induced cholestasis on CYP2D6 expression. Estrogen-induced cholestasis occurs in subjects receiving estrogen for contraception or hormone replacement, or in susceptible women during pregnancy. In CYP2D6-humanized transgenic (Tg-CYP2D6) mice, cholestasis triggered by administration of 17α-ethinylestradiol (EE2) at a high dose led to 2- to 3-fold decreases in CYP2D6 expression. This was accompanied by increased hepatic SHP expression and subsequent decreases in the recruitment of HNF4α to CYP2D6 promoter. Interestingly, estrogen-induced cholestasis also led to increased recruitment of estrogen receptor (ER) α, but not that of FXR, to Shp promoter, suggesting a predominant role of ERα in transcriptional regulation of SHP in estrogen-induced cholestasis. EE2 at a low dose (that does not cause cholestasis) also increased SHP (by ∼50%) and decreased CYP2D6 expression (by 1.5-fold) in Tg-CYP2D6 mice, the magnitude of differences being much smaller than that shown in EE2-induced cholestasis. Taken together, our data indicate that EE2-induced cholestasis increases SHP and represses CYP2D6 expression in Tg-CYP2D6 mice in part through ERα transactivation of Shp promoter. PMID:25943116

  20. CYP2D6: novel genomic structures and alleles

    PubMed Central

    Kramer, Whitney E.; Walker, Denise L.; O’Kane, Dennis J.; Mrazek, David A.; Fisher, Pamela K.; Dukek, Brian A.; Bruflat, Jamie K.; Black, John L.

    2010-01-01

    Objective CYP2D6 is a polymorphic gene. It has been observed to be deleted, to be duplicated and to undergo recombination events involving the CYP2D7 pseudogene and surrounding sequences. The objective of this study was to discover the genomic structure of CYP2D6 recombinants that interfere with clinical genotyping platforms that are available today. Methods Clinical samples containing rare homozygous CYP2D6 alleles, ambiguous readouts, and those with duplication signals and two different alleles were analyzed by long-range PCR amplification of individual genes, PCR fragment analysis, allele-specific primer extension assay, and DNA sequencing to characterize alleles and genomic structure. Results Novel alleles, genomic structures, and the DNA sequence of these structures are described. Interestingly, in 49 of 50 DNA samples that had CYP2D6 gene duplications or multiplications where two alleles were detected, the chromosome containing the duplication or multiplication had identical tandem alleles. Conclusion Several new CYP2D6 alleles and genomic structures are described which will be useful for CYP2D6 genotyping. The findings suggest that the recombination events responsible for CYP2D6 duplications and multiplications are because of mechanisms other than interchromosomal crossover during meiosis. PMID:19741566

  1. Common variants in the CYP2C19 gene are associated with susceptibility to endometriosis

    PubMed Central

    Painter, Jodie N; Nyholt, Dale R; Krause, Lutz; Zhao, Zhen Z; Chapman, Brett; Zhang, Christine; Medland, Sarah; Martin, Nicholas G; Kennedy, Stephen; Treloar, Susan; Zondervan, Krina; Montgomery, Grant W

    2014-01-01

    Objective To follow-up previous studies highlighting a possible role for cytochrome P450, family 2, subfamily C, 19 (CYP2C19) in susceptibility to endometriosis by searching for additional variants in the CYP2C19 gene that may be associated with the disease. Design Case-control study. Setting Academic research. Subject(s) Cases = 2,271 women with surgically confirmed endometriosis; Controls = 939 women with self-report of no endometriosis and 1,770 unscreened population samples. Intervention(s) Sequencing of the CYP2C19 region and follow-up of 80 SNPs in two case-control samples. Main outcome measure(s) Allele frequency differences between cases and controls. Results Sequencing of the CYP2C19 gene region resulted in the detection of a large number of known and novel SNPs. Genotyping of 80 polymorphic SNPs in 901 endometriosis cases and 939 controls resulted in study-wide significant association signals for SNPs in moderate or complete LD with rs4244285, a functional SNP in exon 5 that abrogates CYP2C19 function through the creation of an alternative splice site. Evidence of association was also detected for another functional SNP in the CYP2C19 promoter, rs12248560, highlighted in our previous study. Conclusion(s) Functional variants in CYP2C19 may contribute to endometriosis susceptibility in both familial and sporadic cases. PMID:24796765

  2. Inactive alleles of cytochrome P450 2C19 may be positively selected in human evolution

    PubMed Central

    2014-01-01

    Background Cytochrome P450 CYP2C19 metabolizes a wide range of pharmacologically active substances and a relatively small number of naturally occurring environmental toxins. Poor activity alleles of CYP2C19 are very frequent worldwide, particularly in Asia, raising the possibility that reduced metabolism could be advantageous in some circumstances. The evolutionary selective forces acting on this gene have not previously been investigated. We analyzed CYP2C19 genetic markers from 127 Gambians and on 120 chromosomes from Yoruba, Europeans and Asians (Japanese + Han Chinese) in the Hapmap database. Haplotype breakdown was explored using bifurcation plots and relative extended haplotype homozygosity (REHH). Allele frequency differentiation across populations was estimated using the fixation index (FST) and haplotype diversity with coalescent models. Results Bifurcation plots suggested conservation of alleles conferring slow metabolism (CYP2C19*2 and *3). REHH was high around CYP2C19*2 in Yoruba (REHH 8.3, at 133.3 kb from the core) and to a lesser extent in Europeans (3.5, at 37.7 kb) and Asians (2.8, at −29.7 kb). FST at the CYP2C19 locus was low overall (0.098). CYP2C19*3 was an FST outlier in Asians (0.293), CYP2C19 haplotype diversity < = 0.037, p <0.001. Conclusions We found some evidence that the slow metabolizing allele CYP2C19*2 is subject to positive selective forces worldwide. Similar evidence was also found for CYP2C19*3 which is frequent only in Asia. FST is low at the CYP2C19 locus, suggesting balancing selection overall. The biological factors responsible for these selective pressures are currently unknown. One possible explanation is that early humans were exposed to a ubiquitous novel toxin activated by CYP2C19. The genetic adaptation took place within the last 10,000 years which coincides with the development of systematic agricultural practices. PMID:24690327

  3. Nomenclature for human CYP2D6 alleles.

    PubMed

    Daly, A K; Brockmöller, J; Broly, F; Eichelbaum, M; Evans, W E; Gonzalez, F J; Huang, J D; Idle, J R; Ingelman-Sundberg, M; Ishizaki, T; Jacqz-Aigrain, E; Meyer, U A; Nebert, D W; Steen, V M; Wolf, C R; Zanger, U M

    1996-06-01

    To standardize CYP2D6 allele nomenclature, and to conform with international human gene nomenclature guidelines, an alternative to the current arbitrary system is described. Based on recommendations for human genome nomenclature, we propose that alleles be designated by CYP2D6 followed by an asterisk and a combination of roman letters and arabic numerals distinct for each allele with the number specifying the key mutation and, where appropriate, a letter specifying additional mutations. Criteria for classification as a separate allele and protein nomenclature are also presented. PMID:8807658

  4. Association between cytochrome P450 (CYP) 2C19 polymorphisms and harm avoidance in Japanese.

    PubMed

    Yasui-Furukori, Norio; Kaneda, Ayako; Iwashima, Kumiko; Saito, Manabu; Nakagami, Taku; Tsuchimine, Shoko; Kaneko, Sunao

    2007-09-01

    Polymorphic enzyme cytochrome P450 (CYP) 2C19 is expressed not only in the liver but also in the brain and mediates the biotransformation of 5-hydroxytriptamine (5-HT). We investigated possible association between genetic polymorphism of CYP2C19 and individual personality traits, possibly influenced by neurotransmitters. Mentally and physically healthy Japanese subjects were enrolled in this study (n = 352). Temperament and Character Inventory (TCI) and CYP2C19 genotyping were performed in all subjects. We detected CYP2C19*2 and *3 (http://www.imm.ki.se/CYPalleles/) using Amplichip CYP450 DNA tip. The number of genotypes classified as homozygous extensive metabolizer (EM), heterozygous EM, and poor metabolizer were 113, 181, and 58, respectively. Significant difference was found in TCI score in harm avoidance (HA; F = 3.138, P < 0.05). Post hoc analysis showed that TCI score in harm avoidance in homozygous EM was significantly lower than that in heterozygous EM (P < 0.05) or PM (P < 0.05). In sub-item analyses, HA3 (shyness with strangers, P < 0.01) and HA1 (anticipatory worry, P < 0.05) of TCI scores were significantly different among CYP2C19 genotypes. Meanwhile, there were no differences in TCI scores of novelty seeking (NS; F = 0.350, n.s.), reward dependence (RD; F = 1.080, n.s.), or persistence (P; F = 0.786, n.s.) among CYP2C19 genotypes. This study demonstrated that a significant association between CYP2C19 activity and HA is present in Japanese. PMID:17357148

  5. CYP2C19 polymorphisms in acute coronary syndrome patients undergoing clopidogrel therapy in Zhengzhou population.

    PubMed

    Guo, Y M; Zhao, Z C; Zhang, L; Li, H Z; Li, Z; Sun, H L

    2016-01-01

    The goal of this study was to explore the polymorphisms of CYP2C19 (CYP2C19*2, CYP2C19*3) in patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI) on clopidogrel therapy in Zhengzhou city for guidance on clinical medication and reduction in the incidence of thromboembolic events. Two hundred and thirty-four ACS patients undergoing PCI were included in the study, including 171 males (average age = 64.13 ± 12 years) and 63 females (average age = 67.86 ± 10.20 years). Pyrosequencing analysis detected CYP2C19*2/*3 genotypes, which were divided into wild-type homozygous C/C, mutant heterozygous C/T, and mutant homozygous T/T. This study further explored the relationship between CYP2C19 polymorphisms and clopidogrel resistance in ACS patients. Gene frequencies of C/C, C/T, and T/T for CYP2C19*2 were 39.74, 50, and 10.26%, respectively, while the frequencies of C/C, C/T, and T/T for CYP2C19*3 were 94.02, 5.55, and 0.43%, respectively. According to platelet aggregation analysis, 203 cases normally responded to clopidogrel (86.8%) and 31 cases were clopidogrel resistant (13.2%). There was a correlation between gender and genotype distribution but none between age and genotype. In addition, patients with clopidogrel resistance were treated with ticagrelor antiplatelet therapy instead of clopidogrel, and only 1 case in all patients suffered thrombotic events during a 3-12 month follow-up. In conclusion, CYP2C19*2/*3 polymorphisms may be associated with clopidogrel resistance. Wild-type homozygote and single mutant heterozygote of CYP2C19*2/*3 can be given a normal dose of clopidogrel, while carriers with single mutant homozygote or double mutant heterozygote require ticagrelor antiplatelet therapy as an alternative. PMID:27323099

  6. Phenotype-genotype analysis of CYP2C19 in Colombian mestizo individuals

    PubMed Central

    Isaza, Carlos; Henao, Julieta; Martínez, José H Isaza; Arias, Juan C Sepúlveda; Beltrán, Leonardo

    2007-01-01

    Background Omeprazole is metabolized by the hepatic cytochrome P450 (CYP) 2C19 enzyme to 5-hydroxyomeprazole. CYP2C19 exhibits genetic polymorphisms responsible for the presence of poor metabolizers (PMs), intermediate metabolizers (IMs) and extensive metabolizers (EMs). The defective mutations of the enzyme and their frequencies change between different ethnic groups; however, the polymorphism of the CYP2C19 gene has not been studied in Colombian mestizos. The aim of this study was to evaluate the genotype and phenotype status of CYP2C19 in Colombian mestizos, in order to contribute to the use of appropriate strategies of drug therapy for this population. Methods 189 subjects were genotyped using the multiplex SNaPshot technique and a subgroup of 44 individuals received 20 mg of omeprazole followed by blood collection at 3 hours to determine the omeprazole hydroxylation index by HPLC. Results 83.6%, 15.3% and 1.1% of the subjects were genotyped as EMs, IMs and PMs, respectively. The frequencies of the CYP2C29*1 and CYP2C19*2 alleles were 91.3% and 8.7% respectively whereas the *3, *4, *5, *6 and *8 alleles were not found. No discrepancies were found between the genotype and phenotype of CYP2C19. Conclusion The frequency of poor metabolizers (1.1%) in the Colombian mestizos included in this study is similar to that in Bolivian mestizos (1%) but lower than in Mexican-Americans (3.2%), West Mexicans (6%), Caucasians (5%) and African Americans (5.4%). The results of this study will be useful for drug dosage recommendations in Colombian mestizos. PMID:17623107

  7. The potential for CYP2D6 inhibition screening using a novel scintillation proximity assay-based approach.

    PubMed

    Delaporte, E; Slaughter, D E; Egan, M A; Gatto, G J; Santos, A; Shelley, J; Price, E; Howells, L; Dean, D C; Rodrigues, A D

    2001-08-01

    High throughput inhibition screens for human cytochrome P450s (CYPs) are being used in preclinical drug metabolism to support drug discovery programs. The versatility of scintillation proximity assay (SPA) technology has enabled the development of a homogeneous high throughput assay for cytochrome P450 2D6 (CYP2D6) inhibition screen using [O-methyl-(14)C]dextromethorphan as substrate. The basis of the assay was the trapping of the O-demethylation product, [(14)C]HCHO, on SPA beads. Enzyme kinetics parameters V(max) and apparent K(m), determined using pooled human liver microsomes and microsomes from baculovirus cells coexpressing human CYP2D6 and NADPH-cytochrome P450 reductase, were 245 pmol [(14)C]HCHO/min/mg protein and 11 microM, and 27 pmol [(14)C]HCHO/min/pmol and 1.6 microM, respectively. In incubations containing either pooled microsomes or recombinant CYP2D6, [(14)C]dextromethorphan O-demethylase activity was inhibited in the presence of quinidine (IC(50) = 1.0 microM and 20 nM, respectively). By comparison, inhibitors selective for other CYP isoforms were relatively weak (IC(50) > 25 microM). In agreement, a selective CYP2D6 inhibitory monoclonal antibody caused greater than 90% inhibition of [(14)C]dextromethorphan O-demethylase activity in human liver microsomes, whereas CYP2C9/19- and CYP3A4/5-selective antibodies elicited a minimal inhibitory effect. SPA-based [(14)C]dextromethorphan O-demethylase activity was also shown to correlate (r(2) = 0.6) with dextromethorphan O-demethylase measured by high-performance liquid chromatography in a bank of human liver microsomes (N = 15 different organ donors). In a series of known CYP2D6 inhibitors/substrates, the SPA-based assay resolved potent inhibitors (IC(50) < 2 microM) from weak inhibitors (IC(50) >or= 20 microM). It is concluded that the SPA-based assay described herein is suitable for CYP2D6 inhibition screening using either native human liver microsomes or cDNA-expressed CYP2D6. PMID:11689122

  8. Cytochrome P450-2D6 Screening Among Elderly Using Antidepressants (CYSCE)

    ClinicalTrials.gov

    2016-10-24

    Depression; Depressive Disorder; Poor Metabolizer Due to Cytochrome P450 CYP2D6 Variant; Intermediate Metabolizer Due to Cytochrome P450 CYP2D6 Variant; Ultrarapid Metabolizer Due to Cytochrome P450 CYP2D6 Variant

  9. High-throughput radiometric CYP2C19 inhibition assay using tritiated (S)-mephenytoin.

    PubMed

    Di Marco, Annalise; Cellucci, Antonella; Chaudhary, Ashok; Fonsi, Massimiliano; Laufer, Ralph

    2007-10-01

    A rapid and sensitive radiometric assay for assessing the potential of drugs to inhibit cytochrome P450 (P450) 2C19 in human liver microsomes is described. The new assay, which does not require high-performance liquid chromatography (HPLC) separation or mass spectrometric detection, is based on the release of tritium as tritiated water that occurs upon CYP2C19-mediated 4'-hydroxylation of (S)-mephenytoin labeled with tritium in the 4' position. Because this reaction is subject to an NIH shift, tritium was also introduced into the 3'- and 5'-positions of the tracer to enhance formation of a tritiated water product. Tritiated water was separated from the substrate using 96-well solid-phase extraction plates. The reaction is NADPH-dependent and sensitive to CYP2C19 inhibitors. IC(50) values for 15 diverse drugs differed less than 2.5-fold from those determined by quantification of the unlabeled 4'-hydroxy-(S)-mephenytoin product, using HPLC coupled to mass spectrometric detection. All of the steps of the new assay, namely incubation, product separation, and radioactivity counting, are performed in a 96-well format and can be automated. This assay represents a non-HPLC, high-throughput version of the classic (S)-mephenytoin 4'-hydroxylation assay, which is the most widely used method to assess the potential for CYP2C19 inhibition of new chemical entities.

  10. 76 FR 77833 - Scientific Information Request on CYP2C19 Variants and Platelet Reactivity Tests

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-14

    ... Variants and Platelet Reactivity Tests AGENCY: Agency for Healthcare Research and Quality (AHRQ), HHS... platelet reactivity tests. Scientific information is being solicited to inform our Comparative... for studies that report on CYP2C19 variants and platelet reactivity tests, including those...

  11. Human cytochrome P450-catalyzed conversion of the proestrogenic pesticide methoxychlor into an estrogen. Role of CYP2C19 and CYP1A2 in O-demethylation.

    PubMed

    Stresser, D M; Kupfer, D

    1998-09-01

    1,1,1-Trichloro-2,2-bis(4-methoxyphenyl)ethane (methoxychlor) is a widely used pesticide that is pro-estrogenic. We have elucidated the human cytochrome P450 enzymes responsible for conversion of methoxychlor into its major metabolite, the mono-O-demethylated derivative (mono-OH-M) that is estrogenic. Incubation of methoxychlor with microsomes from insect cells overexpressing either CYP1A2, CYP2C18, or CYP2C19 yielded mono-OH-M with turnover numbers of 14.9, 15.5, and 39.1 nmol/min/nmol of P450, respectively. CYP2B6 and CYP2C9 were much less active. Incubations with purified CYP2C19 and CYP2C18 resulted in formation of mono-OH-M, and also the bis-demethylated metabolite. Co-incubation of liver microsomes with methoxychlor and various P450 isoform-selective inhibitors suggested involvement of several P450s in mono-O-demethylation, including CYP1A2, CYP2A6, CYP2C9, and CYP2C19. A role for CYP2C19, CYP1A2, and CYP2A6 was also indicated by multivariate regression analysis of the mono-O-demethylase activity in a panel of human liver microsomes characterized for isoform-specific catalytic activities (R2 = 0.96). Based on the totality of the evidence, CYP2C19 appears to be the major catalyst of methoxychlor mono-O-demethylation. However, in individuals lacking functional CYP2C19 (e.g. the "poor metabolizer" phenotype), CYP1A2 may play the predominant role. CYP2A6, CYP2C9, and CYP2B6 probably contribute to a lesser extent. Although CYP2C18 is an efficient methoxychlor demethylase, its expression in liver is reportedly low or absent, suggesting a negligible role for this enzyme in methoxychlor metabolism. Lengthy incubations of liver microsomes with methoxychlor produced other secondary and tertiary metabolites. Efficient conversion of methoxychlor to estrogenic mono-OH-M by liver microsomes suggests that methoxychlor has the potential to be estrogenic in humans, as observed in several animal species.

  12. Effect of CYP2C9 genetic polymorphism on the metabolism of flurbiprofen in vitro.

    PubMed

    Wang, Li; Bao, Shi-Hui; Pan, Pei-Pei; Xia, Meng-Ming; Chen, Meng-Chun; Liang, Bing-Qing; Dai, Da-Peng; Cai, Jian-Ping; Hu, Guo-Xin

    2015-01-01

    CYP2C9 is an important member of the cytochrome P450 enzyme superfamily, and 57 cytochrome P450 2C9 alleles have been previously reported. To examine the enzymatic activity of the CYP2C9 alleles, kinetic parameters for 4'-hydroxyflurbiprofen were determined using recombinant human P450s CYP2C9 microsomes from insect cells Sf21 carrying wild-type CYP2C9*1 and other variants. The results showed that the enzyme activity of most of the variants decreased comparing with the wild type as the previous studies reported, while the enzyme activity of some of them increased, which were not in accordance with the previous researches. Of the 36 tested CYP2C9 allelic isoforms, two variants (CYP2C9*53 and CYP2C9*56) showed a higher intrinsic clearance value than the wild-type protein, especially for CYP2C9*56, exhibited much higher intrinsic clearance (197.3%) relative to wild-type CYP2C9*1, while the remaining 33 CYP2C9 allelic isoforms exhibited significantly decreased clearance values (from 0.6 to 83.8%) compared to CYP2C9*1. This study provided the most comprehensive data on the enzymatic activities of all reported CYP2C9 variants in the Chinese population with regard to the commonly used non-steroidal anti-inflammatory drug, flurbiprofen (FP). The results indicated that most of the tested rare alleles decreased the catalytic activity of CYP2C9 variants toward FP hydroxylation in vitro. This is the first report of all these rare alleles for FP metabolism providing fundamental data for further clinical studies on CYP2C9 alleles for FP metabolism in vivo.

  13. Inhibitory effects of phytochemicals on metabolic capabilities of CYP2D6*1 and CYP2D6*10 using cell-based models in vitro

    PubMed Central

    Qu, Qiang; Qu, Jian; Han, Lu; Zhan, Min; Wu, Lan-xiang; Zhang, Yi-wen; Zhang, Wei; Zhou, Hong-hao

    2014-01-01

    Aim: Herbal products have been widely used, and the safety of herb-drug interactions has aroused intensive concerns. This study aimed to investigate the effects of phytochemicals on the catalytic activities of human CYP2D6*1 and CYP2D6*10 in vitro. Methods: HepG2 cells were stably transfected with CYP2D6*1 and CYP2D6*10 expression vectors. The metabolic kinetics of the enzymes was studied using HPLC and fluorimetry. Results: HepG2-CYP2D6*1 and HepG2-CYP2D6*10 cell lines were successfully constructed. Among the 63 phytochemicals screened, 6 compounds, including coptisine sulfate, bilobalide, schizandrin B, luteolin, schizandrin A and puerarin, at 100 μmol/L inhibited CYP2D6*1- and CYP2D6*10-mediated O-demethylation of a coumarin compound AMMC by more than 50%. Furthermore, the inhibition by these compounds was dose-dependent. Eadie-Hofstee plots demonstrated that these compounds competitively inhibited CYP2D6*1 and CYP2D6*10. However, their Ki values for CYP2D6*1 and CYP2D6*10 were very close, suggesting that genotype-dependent herb-drug inhibition was similar between the two variants. Conclusion: Six phytochemicals inhibit CYP2D6*1 and CYP2D6*10-mediated catalytic activities in a dose-dependent manner in vitro. Thus herbal products containing these phytochemicals may inhibit the in vivo metabolism of co-administered drugs whose primary route of elimination is CYP2D6. PMID:24786236

  14. Decreased hippocampal volume and increased anxiety in a transgenic mouse model expressing the human CYP2C19 gene

    PubMed Central

    Persson, A; Sim, S C; Virding, S; Onishchenko, N; Schulte, G; Ingelman-Sundberg, M

    2014-01-01

    Selective serotonin reuptake inhibitors, tricyclic antidepressants, various psychoactive drugs, as well as endogenous steroids and cannabinoid-like compounds are metabolized by the polymorphic cytochrome P450 2C19 (CYP2C19). Absence of this enzyme has been recently shown to associate with lower levels of depressive symptoms in human subjects. To investigate endogenous functions of CYP2C19 and its potential role in brain function, we have used a transgenic mouse model carrying the human CYP2C19 gene. Here, CYP2C19 was expressed in the developing fetal, but not adult brain and was associated with altered fetal brain morphology, where mice homozygous for the CYP2C19 transgenic insert had severely underdeveloped hippocampus and complete callosal agenesis and high neonatal lethality. CYP2C19 expression was also found in human fetal brain. In adult hemizygous mice we observed besides decreased hippocampal volume, an altered neuronal composition in the hippocampal dentate gyrus. Reduced hippocampal volumes have been reported in several psychiatric disorders, supporting the relevance of this model. Here we found that adult hemizygous CYP2C19 transgenic mice demonstrate behavior indicative of increased stress and anxiety based on four different tests. We hypothesize that expression of the CYP2C19 enzyme prenatally may affect brain development by metabolizing endogenous compounds influencing this development. Furthermore, CYP2C19 polymorphism may have a role in interindividual susceptibility for psychiatric disorders. PMID:23877834

  15. Insights into drug metabolism by cytochromes P450 from modelling studies of CYP2D6-drug interactions.

    PubMed

    Maréchal, J-D; Kemp, C A; Roberts, G C K; Paine, M J I; Wolf, C R; Sutcliffe, M J

    2008-03-01

    The cytochromes P450 (CYPs) comprise a vast superfamily of enzymes found in virtually all life forms. In mammals, xenobiotic metabolizing CYPs provide crucial protection from the effects of exposure to a wide variety of chemicals, including environmental toxins and therapeutic drugs. Ideally, the information on the possible metabolism by CYPs required during drug development would be obtained from crystal structures of all the CYPs of interest. For some years only crystal structures of distantly related bacterial CYPs were available and homology modelling techniques were used to bridge the gap and produce structural models of human CYPs, and thereby obtain useful functional information. A significant step forward in the reliability of these models came seven years ago with the first crystal structure of a mammalian CYP, rabbit CYP2C5, followed by the structures of six human enzymes, CYP1A2, CYP2A6, CYP2C8, CYP2C9, CYP2D6 and CYP3A4, and a second rabbit enzyme, CYP2B4. In this review we describe as a case study the evolution of a CYP2D6 model, leading to the validation of the model as an in silico tool for predicting binding and metabolism. This work has led directly to the successful design of CYP2D6 mutants with novel activity-including creating a testosterone hydroxylase, converting quinidine from inhibitor to substrate, creating a diclofenac hydroxylase and creating a dextromethorphan O-demethylase. Our modelling-derived hypothesis-driven integrated interdisciplinary studies have given key insight into the molecular determinants of CYP2D6 and other important drug metabolizing enzymes. PMID:18026129

  16. Role of cytochrome P450 2D6 genetic polymorphism in carvedilol hydroxylation in vitro

    PubMed Central

    Wang, Zhe; Wang, Li; Xu, Ren-ai; Zhan, Yun-yun; Huang, Cheng-ke; Dai, Da-peng; Cai, Jian-ping; Hu, Guo-xin

    2016-01-01

    Cytochrome P450 2D6 (CYP2D6) is a highly polymorphic enzyme that catalyzes the metabolism of a great number of therapeutic drugs. Up to now, >100 allelic variants of CYP2D6 have been reported. Recently, we identified 22 novel variants in the Chinese population in these variants. The purpose of this study was to examine the enzymatic activity of the variants toward the CYP2D6 substrate carvedilol in vitro. The CYP2D6 proteins, including CYP2D6.1 (wild type), CYP2D6.2, CYP2D6.10, and 22 other novel CYP2D6 variants, were expressed from insect microsomes and incubated with carvedilol ranging from 1.0 μM to 50 μM at 37°C for 30 minutes. After termination, the carvedilol metabolites were extracted and detected using ultra-performance liquid chromatography tandem mass-spectrometry. Among the 24 CYP2D6 variants, CYP2D6.92 and CYP2D6.96 were catalytically inactive and the remaining 22 variants exhibited significantly decreased intrinsic clearance values (ranging from ~25% to 95%) compared with CYP2D6.1. The present data in vitro suggest that the newly found variants significantly reduced catalytic activities compared with CYP2D6.1. Given that CYP2D6 protein activities could affect carvedilol plasma levels, these findings are greatly relevant to personalized medicine. PMID:27354764

  17. Genetic polymorphisms and phenotypic analysis of drug-metabolizing enzyme CYP2C19 in a Li Chinese population.

    PubMed

    Ding, Yipeng; Xu, Dongchuan; Zhang, Xiyang; Yang, Hua; Geng, Tingting; He, Ping; Yao, Jinjian; Yi, Shengyang; Xu, Heping; Wu, Duoyi; Wang, Xiang; Jin, Tianbo

    2015-01-01

    CYP2C19 is a highly polymorphic gene and CYP2C19 enzyme results in broad inter-individual variability in response to certain clinical drugs, while little is known about the genetic variation of CYP2C19 in Li Chinese population. The aim of this study was to identify different CYP2C19 mutant alleles and determine their frequencies, along with genotype frequencies, in the Li Chinese population. We used DNA sequencing to investigate promoter, exons, introns, and 3'UTR of the CYP2C19 gene in 100 unrelated healthy Li individuals from Hainan Province, China. We also used SIFT and PolyPhen-2 to predict the protein function of the non-synonymous mutation in CYP2C19 coding regions. We identified 22 different CYP2C19 polymorphisms in the Li Chinese population, including three novel variants (-254A > G, 17807T > C and 58025C > T). The allele frequencies of CYP2C19*1A, *1B, *2A and *3A were 50%, 24%, 24.5%, and 1.5%, respectively. The most common genotype combinations were *1A/*1B (48%) and *1A/*2A (49%). Additionally, the mutation Ala161Pro was predicted to be intolerant and possibly damaging by SIFT and PolyPhen-2, respectively. Our results shed new light on CYP2C19 polymorphisms in Li individuals, which may help to optimize pharmacotherapy effectiveness by providing personalized medicine to this ethnic group.

  18. Frequency of CYP2C9 alleles in Koreans and their effects on losartan pharmacokinetics

    PubMed Central

    Bae, Jung-woo; Choi, Chang-ik; Kim, Mi-jeong; Oh, Da-hee; Keum, Seul-ki; Park, Jung-in; Kim, Bo-hye; Bang, Hye-kyoung; Oh, Sung-gon; Kang, Byung-sung; Park, Hyun-joo; Kim, Hae-deun; Ha, Ji-hey; Shin, Hee-jung; Kim, Young-hoon; Na, Han-sung; Chung, Myeon-woo; Jang, Choon-gon; Lee, Seok-yong

    2011-01-01

    Aim: CYP2C9 enzyme metabolizes numerous clinically important drugs. The aim of this study is to investigate the frequencies of CYP2C9 genotypes and the effects of selected alleles on losartan pharmacokinetics in a large sample of the Korean population. Methods: The CYP2C9 gene was genotyped in 1796 healthy Korean subjects. CYP2C9 alleles (CYP2C9*1, *2, *3 and *13 alleles) were measured using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay and direct sequencing assay. The enzymatic activity of each CYP2C9 genotype was evaluated using losartan as the substrate. Results: The frequencies of CYP2C9*1, *3 and *13 allele were 0.952 (95% confidence interval 0.945–0.959), 0.044 (95% CI 0.037–0.051) and 0.005 (95% CI 0.003–0.007), respectively. The frequencies of the CYP2C9*1/*1, *1/*3, *1/*13 and *3/*3 genotypes were 0.904 (95% CI 0.890–0.918), 0.085 (95% CI 0.072–0.098), 0.009 (95% CI 0.005–0.013) and 0.001 (95% CI 0.000–0.002), respectively. In the pharmacokinetics studies, the AUC0–∞ of losartan in CYP2C9*3/*3 subjects was 1.42-fold larger than that in CYP2C9*1/*1 subjects, and the AUC0–∞ of E-3174, a more active metabolite of losartan, in CYP2C9*3/*3 subjects was only 12% of that in CYP2C9*1/*1 subjects. Conclusion: The results confirmed the frequencies of CYP2C9 genotypes in a large cohort of Koreans, and detected the CYP2C9*3/*3 genotype. CYP2C9*3/*3 subjects metabolized much less losartan into E-3174 than CYP2C9*1/*1 subjects. PMID:21841812

  19. Autoantibodies against CYP2D6 and other drug-metabolizing enzymes in autoimmune hepatitis type 2.

    PubMed

    Mizutani, Takaharu; Shinoda, Masakazu; Tanaka, Yuta; Kuno, Takuya; Hattori, Asuka; Usui, Toru; Kuno, Nayumi; Osaka, Takashi

    2005-01-01

    Autoimmune hepatitis (AIH) is a disease of unknown etiology, characterized by liver-related autoantibodies. Autoimmune hepatitis is subdivided into two major types: AIH type 1 is characterized by the detection of ANA, SMA, ANCA, anti-ASGP-R, and anti-SLA/LP. Autoimmune hepatitis type 2 is characterized to be mainly related with drug-metabolizing enzymes as autoantigens, such as anti-LKM (liver-kidney microsomal antigen)-1 against CYP2D6, anti-LKM-2 against CYP2C9-tienilic acid, anti-LKM-3 against UGT1A, and anti-LC1 (liver cytosol antigen)-1 and anti-APS (autoimmune polyglandular syndrome type-1) against CYP1A2, CYP2A6, and others. Anti-LKM-1 sera inhibited CYP2D6 activity in vitro but did not inhibit cellular drug metabolism in vivo. CYP2D6 is the major target autoantigen of LKM-1 and expressed on plasma membrane (PM) of hepatocytes, suggesting a pathogenic role for anti-LKM-1 in liver injury as a trigger. Anti-CYP1A2 was observed in dihydralazine-induced hepatitis, and radiolabeled CYP1A2 disappeared from the PM with a half-life of less than 30 min, whereas microsomal CYP1A2 was stably radiolabeled for several hours. Main antigenic epitopes on CYP2D6 are aa 193-212, aa 257-269, and aa 321-351; and D263 is essential. The third epitope is located on the surface of the protein CYP2D6 and displays a hydrophobic patch that is situated between an aromatic residue (W316) and histidine (H326). Some drugs such as anticonvulsants (phenobarbital, phenytoin, and carbamazepine) and halothane are suggested to induce hepatitis with anti-CYP3A and anti-CYP2E1, respectively. Autoantibodies against CYP11A1, CYP17, and/or CYP21 involved in the synthesis of steroid hormones are also detected in patients with adrenal failure, gonadal failure, and/or Addison disease.

  20. CYP2C19 Phenoconversion by Routinely Prescribed Proton Pump Inhibitors Omeprazole and Esomeprazole: Clinical Implications for Personalized Medicine.

    PubMed

    Klieber, Martin; Oberacher, Herbert; Hofstaetter, Silvia; Beer, Beate; Neururer, Martin; Amann, Anton; Alber, Hannes; Modak, Anil

    2015-09-01

    The phenotype pantoprazole-(13)C breath test (Ptz-BT) was used to evaluate the extent of phenoconversion of CYP2C19 enzyme activity caused by commonly prescribed proton pump inhibitors (PPI) omeprazole and esomprazole. The Ptz-BT was administered to 26 healthy volunteers and 8 stable cardiovascular patients twice at baseline and after 28 days of PPI therapy to evaluate reproducibility of the Ptz-BT and changes in CYP2C19 enzyme activity (phenoconversion) after PPI therapy. The average intrapatient interday variability in CYP2C19 phenotype (n = 31) determined by Ptz-BT was considerably low (coefficient of variation, 17%). Phenotype conversion resulted in 25 of 26 (96%) nonpoor metabolizer (non-PM) volunteers/patients as measured by the Ptz-BT at baseline and after PPI therapy. The incidence of PM status by phenotype following administration of omeprazole/esomeprazole (known inhibitors of CYP2C19) was 10-fold higher than those who are genetically PMs in the general population, which could have critical clinical implications for personalizing medications primarily metabolized by CYP2C19, such as clopidogrel, PPI, cyclophosphamide, thalidomide, citalopram, clonazepam, diazepam, phenytoin, etc. The Ptz-BT can rapidly (30 minutes) evaluate CYP2C19 phenotype and, more importantly, can identify patients with phenoconversion in CYP2C19 enzyme activity caused by nongenetic factors such as concomitant drugs. PMID:26159874

  1. CYP2C19 Polymorphisms and Therapeutic Drug Monitoring of Voriconazole: Are We Ready for Clinical Implementation of Pharmacogenomics?

    PubMed Central

    Obeng, Aniwaa Owusu; Egelund, Eric F.; Alsultan, Abdullah; Peloquin, Charles A.; Johnson, Julie A.

    2014-01-01

    Since its approval by the United States Food and Drug Administration in 2002, voriconazole has become a key component in the successful treatment of many invasive fungal infections, including the most common, aspergillosis and candidiasis. Despite voriconazole’s widespread use, optimizing its treatment in an individual can be challenging due to significant interpatient variability in plasma concentrations of the drug. Variability is due to nonlinear pharmacokinetics and the influence of patient characteristics such as age, sex, weight, liver disease, and genetic polymorphisms in the cytochrome P450 2C19 gene (CYP2C19) encoding for the CYP2C19 enzyme, the primary enzyme responsible for metabolism of voriconazole. CYP2C19 polymorphisms account for the largest portion of variability in voriconazole exposure, posing significant difficulty to clinicians in targeting therapeutic concentrations. In this review, we discuss the role of CYP2C19 polymorphisms and their influence on voriconazole’s pharmacokinetics, adverse effects, and clinical efficacy. Given the association between CYP2C19 genotype and voriconazole concentrations, as well as the association between voriconazole concentrations and clinical outcomes, particularly efficacy, it seems reasonable to suggest a potential role for CYP2C19 genotype to guide initial voriconazole dose selection followed by therapeutic drug monitoring to increase the probability of achieving efficacy while avoiding toxicity. PMID:24510446

  2. CYP2D6 Genetic Polymorphisms and Phenotypes in Different Ethnicities of Malaysian Breast Cancer Patients.

    PubMed

    Chin, Fee Wai; Chan, Soon Choy; Abdul Rahman, Sabariah; Noor Akmal, Sharifah; Rosli, Rozita

    2016-01-01

    The cytochrome P450, family 2, subfamily D, polypeptide 6 (CYP2D6) is an enzyme that is predominantly involved in the metabolism of tamoxifen. Genetic polymorphisms of the CYP2D6 gene may contribute to inter-individual variability in tamoxifen metabolism, which leads to the differences in clinical response to tamoxifen among breast cancer patients. In Malaysia, the knowledge on CYP2D6 genetic polymorphisms as well as metabolizer status in Malaysian breast cancer patients remains unknown. Hence, this study aimed to comprehensively identify CYP2D6 genetic polymorphisms among 80 Malaysian breast cancer patients. The genetic polymorphisms of all the 9 exons of CYP2D6 gene were identified using high-resolution melting analysis and confirmed by DNA sequencing. Seven CYP2D6 alleles consisting of CYP2D6*1, CYP2D6*2, CYP2D6*4, CYP2D6*10, CYP2D6*39, CYP2D6*49, and CYP2D6*75 were identified in this study. Among these alleles, CYP2D6*10 is the most common allele in both Malaysian Malay (54.8%) and Chinese (71.4%) breast cancer patients, whereas CYP2D6*4 in Malaysian Indian (28.6%) breast cancer patients. In relation to CYP2D6 genotype, CYP2D6*10/*10 is more frequently observed in both Malaysian Malay (28.9%) and Chinese (57.1%) breast cancer patients, whereas CYP2D6*4/*10 is more frequently observed in Malaysian Indian (42.8%) breast cancer patients. In terms of CYP2D6 phenotype, 61.5% of Malaysian Malay breast cancer patients are predicted as extensive metabolizers in which they are most likely to respond well to tamoxifen therapy. However, 57.1% of Chinese as well as Indian breast cancer patients are predicted as intermediate metabolizers and they are less likely to gain optimal benefit from the tamoxifen therapy. This is the first report of CYP2D6 genetic polymorphisms and phenotypes in Malaysian breast cancer patients for different ethnicities. These data may aid clinicians in selecting an optimal drug therapy for Malaysian breast cancer patients, hence improve the

  3. Genetic mechanisms for duplication and multiduplication of the human CYP2D6 gene and methods for detection of duplicated CYP2D6 genes.

    PubMed

    Lundqvist, E; Johansson, I; Ingelman-Sundberg, M

    1999-01-21

    The polymorphic CYP2D6 gene determines the rates at which several different classes of clinically important drugs are metabolized in vivo. A specific phenotype whereby a subject metabolizes drugs very rapidly (ultrarapid metabolizer, UM) has been shown to be caused by the presence of multiple active CYP2D6 genes on one allele. Hitherto, individuals with 1, 2, 3, 4, 5, or 13 CYP2D6 genes in tandem have been described for various ethnic groups. In the present investigation, we present results from restriction mapping of the CYP2D loci of individuals with two or more consecutive CYP2D6 genes, along with sequence analysis of this gene (CYP2D6*2). Our results indicate that alleles with duplicated or multiduplicated genes have occurred through unequal crossover at a specific breakpoint in the 3'-flanking region of the CYP2D6*2B allele with a specific repetitive sequence. In contrast, alleles with 13 copies of the gene are proposed to have been formed by unequal segregation and extrachromosomal replication of the acentric DNA. We present a rapid and efficient PCR-based allele-specific method for the detection of duplicated, multiduplicated, or amplified CYP2D6 genes.

  4. Mechanism of CYP2C9 inhibition by flavones and flavonols.

    PubMed

    Si, Dayong; Wang, Ying; Zhou, Yi-Han; Guo, Yingjie; Wang, Juan; Zhou, Hui; Li, Ze-Sheng; Fawcett, J Paul

    2009-03-01

    This article describes an in vitro investigation of the inhibition of cytochrome P450 (P450) 2C9 by a series of flavonoids made up of flavones (flavone, 6-hydroxyflavone, 7-hydroxyflavone, chrysin, baicalein, apigenin, luteolin, scutellarein, and wogonin) and flavonols (galangin, fisetin, kaempferol, morin, and quercetin). With the exception of flavone, all flavonoids were shown to inhibit CYP2C9-mediated diclofenac 4'-hydroxylation in the CYP2C9 RECO system, with K(i) value 2C9, whereas the other flavonoids were competitive inhibitors. Computer docking simulation and constructed mutants substituted at residue 100 of CYP2C9.1 indicate that the noncompetitive binding site of 6-hydroxyflavone lies beside Phe100, similar to the reported allosteric binding site of warfarin. The other flavonoids exert competitive inhibition through interaction with the substrate binding site of CYP2C9 accessed by flurbiprofen. These results suggest flavonoids can participate in interactions with drugs that act as substrates for CYP2C9 and provide a possible molecular basis for understanding cooperativity in human P450-mediated drug-drug interactions. PMID:19074529

  5. Guanfu base A, an antiarrhythmic alkaloid of Aconitum coreanum, Is a CYP2D6 inhibitor of human, monkey, and dog isoforms.

    PubMed

    Sun, Jianguo; Peng, Ying; Wu, Hui; Zhang, Xueyuan; Zhong, Yunxi; Xiao, Yanan; Zhang, Fengyi; Qi, Huanhuan; Shang, Lili; Zhu, Jianping; Sun, Yue; Liu, Ke; Liu, Jinghan; A, Jiye; Ho, Rodney J Y; Wang, Guangji

    2015-05-01

    Guanfu base A (GFA) is a novel heterocyclic antiarrhythmic drug isolated from Aconitum coreanum (Lèvl.) rapaics and is currently in a phase IV clinical trial in China. However, no study has investigated the influence of GFA on cytochrome P450 (P450) drug metabolism. We characterized the potency and specificity of GFA CYP2D inhibition based on dextromethorphan O-demethylation, a CYP2D6 probe substrate of activity in human, mouse, rat, dog, and monkey liver microsomes. In addition, (+)-bufuralol 1'-hydroxylation was used as a CYP2D6 probe for the recombinant form (rCYP2D6), 2D1 (rCYP2D1), and 2D2 (rCYP2D2) activities. Results show that GFA is a potent noncompetitive inhibitor of CYP2D6, with inhibition constant Ki = 1.20 ± 0.33 μM in human liver microsomes (HLMs) and Ki = 0.37 ± 0.16 μM for the human recombinant form (rCYP2D6). GFA is also a potent competitive inhibitor of CYP2D in monkey (Ki = 0.38 ± 0.12 μM) and dog (Ki = 2.4 ± 1.3 μM) microsomes. However, GFA has no inhibitory activity on mouse or rat CYP2Ds. GFA did not exhibit any inhibition activity on human recombinant CYP1A2, 2A6, 2C8, 2C19, 3A4, or 3A5, but showed slight inhibition of 2B6 and 2E1. Preincubation of HLMs and rCYP2D6 resulted in the inactivation of the enzyme, which was attenuated by GFA or quinidine. Beagle dogs treated intravenously with dextromethorphan (2 mg/ml) after pretreatment with GFA injection showed reduced CYP2D metabolic activity, with the Cmax of dextrorphan being one-third that of the saline-treated group and area under the plasma concentration-time curve half that of the saline-treated group. This study suggests that GFA is a specific CYP2D6 inhibitor that might play a role in CYP2D6 medicated drug-drug interaction.

  6. Potential role of CYP2D6 in the central nervous system

    PubMed Central

    Cheng, Jie; Zhen, Yueying; Miksys, Sharon; Beyoğlu, Diren; Krausz, Kristopher W.; Tyndale, Rachel F.; Yu, Aiming; Idle, Jeffrey R.; Gonzalez, Frank J.

    2013-01-01

    Cytochrome P450 2D6 (CYP2D6) is a pivotal enzyme responsible for a major human drug oxidation polymorphism in human populations. Distribution of CYP2D6 in brain and its role in serotonin metabolism suggest this CYP2D6 may have a function in central nervous system. To establish an efficient and accurate platform for the study of CYP2D6 in vivo, a transgenic human CYP2D6 (Tg-2D6) model was generated by transgenesis in wild-type C57BL/6 (WT) mice using a P1 phage artificial chromosome clone containing the complete human CYP2D locus, including CYP2D6 gene and 5’- and 3’- flanking sequences. Human CYP2D6 was expressed not only in the liver, but also in brain. The abundance of serotonin and 5-hydroxyindoleacetic acid in brain of Tg-2D6 is higher than in WT mice either basal levels or after harmaline induction. Metabolomics of brain homogenate and cerebrospinal fluid revealed a significant up-regulation of l-carnitine, acetyl-l-carnitine, pantothenic acid, dCDP, anandamide, N-acetylglucosaminylamine, and a down-regulation of stearoyl-l-carnitine in Tg-2D6 mice compared with WT mice. Anxiety tests indicate Tg-2D6 mice have a higher capability to adapt to anxiety. Overall, these findings indicate that the Tg-2D6 mouse model may serve as a valuable in vivo tool to determine CYP2D6-involved neurophysiological metabolism and function. PMID:23614566

  7. Prevalence of CYP2D6*2, CYP2D6*4, CYP2D6*10, and CYP3A5*3 in Thai breast cancer patients undergoing tamoxifen treatment

    PubMed Central

    Charoenchokthavee, Wanaporn; Panomvana, Duangchit; Sriuranpong, Virote; Areepium, Nutthada

    2016-01-01

    Background Tamoxifen (TAM) is used in breast cancer treatment, but interindividual variabilities in TAM-metabolizing enzymes exist and have been linked to single nucleotide polymorphisms in the respective encoding genes. The different alleles and genotypes of these genes have been presented for Caucasians and Asians. This study aimed to explore the prevalence of the incomplete functional alleles and genotypes of the CYP2D6 and CYP3A5 genes in Thai breast cancer patients undergoing TAM treatment. Patients and methods In total, 134 Thai breast cancer patients were randomly invited to join the Thai Tamoxifen Project. Their blood samples were collected and extracted for individual DNA. The alleles and genotypes were determined by real-time polymerase chain reaction with TaqMan® Drug Metabolism Genotyping Assays. Results The patients were aged from 27.0 years to 82.0 years with a body mass index range from 15.4 to 40.0, with the majority (103/134) in the early stage (stages 0–II) of breast cancer. The median duration of TAM administration was 17.2 months (interquartile range 16.1 months). Most (53%) of the patients were premenopausal with an estrogen receptor (ER) and progesterone receptor (PR) status of ER+/PR+ (71.7%), ER+/PR− (26.9%), ER−/PR+ (0.7%), and ER−/PR− (0.7%). The allele frequencies of CYP2D6*1, CYP2D6*2, CYP2D6*4, CYP2D6*10, CYP3A5*1, and CYP3A5*3 were 72.9%, 3.2%, 1.1%, 22.8%, 37.3%, and 62.7%, respectively, while the genotype frequencies of CYP2D6*1/*1, CYP2D6*1/*2, CYP2D6*2/*2, CYP2D6*4/*4, CYP2D6*1/*10, CYP2D6*2/*10, CYP2D6*4/*10, CYP2D6*10/*10, CYP3A5*1/*1, CYP3A5*1/*3, and CYP3A5*3/*3 were 9.7%, 2.2%, 3.7%, 1.5%, 15.7%, 9.7%, 3.7%, 53.7%, 13.4%, 47.8%, and 38.8%, respectively. Conclusion The majority (97.8%) of Thai breast cancer patients undergoing TAM treatment carry at least one incomplete functional allele, including 20.9% of the patients who carry only incomplete functional alleles for both the CYP2D6 and CYP3A5 genes. This research

  8. A Case of Intolerance to Warfarin Dosing in an Intermediate Metabolizer of CYP2C9

    PubMed Central

    Lee, Soo-Youn; Kim, June Soo

    2005-01-01

    We report a case of intolerance to warfarin dosing due to impaired drug metabolism in a patient heterozygous for the CYP2C9*3 allele. A 30-year-old woman with an artificial cardiac pacemaker was taking warfarin to prevent thromboembolism. This patient had an extremely elevated international normalized ratio (INR) of prothrombin time (PT) following standard doses of warfarin and experienced difficulties during the induction of anticoagulation. Genotyping for CYP2C9 revealed that this patient was an intermediate metabolizer with genotype CYP2C9*1/*3. This case suggests the clinical usefulness of pharmacogenetic testing for individualized dosage adjustments of warfarin. PMID:16385662

  9. CYP2C19 Metabolizer Status and Clopidogrel Efficacy in the Secondary Prevention of Small Subcortical Strokes (SPS3) Study

    PubMed Central

    McDonough, Caitrin W; McClure, Leslie A; Mitchell, Braxton D; Gong, Yan; Horenstein, Richard B; Lewis, Joshua P; Field, Thalia S; Talbert, Robert L; Benavente, Oscar R; Johnson, Julie A; Shuldiner, Alan R

    2015-01-01

    Background The role of the CYP2C19 genotype on clopidogrel efficacy has been studied widely, with data suggesting reduced clopidogrel efficacy in loss-of-function variant carriers taking clopidogrel after percutaneous coronary intervention; however, data are limited regarding the association between CYP2C19 genetic variants and outcomes in stroke patients. We investigated whether CYP2C19 metabolizer status affects the risk of recurrent stroke or major bleeding in subcortical stroke patients taking dual antiplatelet therapy with aspirin and clopidogrel. Methods and Results CYP2C19*2 and CYP2C19*17 were genotyped in 522 patients treated with dual antiplatelet therapy from the Secondary Prevention of Small Subcortical Strokes (SPS3) study. CYP2C19 metabolizer status was inferred from genotype, and associations with the risk of recurrent stroke and major bleeding were assessed in the overall cohort and by race/ethnic group with logistic regression modeling. In the overall cohort, there were no differences in outcomes by CYP2C19 metabolizer status (recurrent stroke, odds ratio 1.81 [95% CI 0.76 to 4.30]; major bleeding, odds ratio 0.67 [95% CI 0.22 to 2.03]). In white participants, those with CYP2C19 intermediate or poor metabolizer status had higher odds of recurrent stroke (odds ratio 5.19 [95% CI 1.08 to 24.90]) than those with extensive or ultrarapid metabolizer status, but there was no evidence of difference in major bleeding. Conclusions There were significant differences in recurrent stroke by CYP2C19 genotype-inferred metabolizer status in white subcortical stroke patients receiving dual antiplatelet therapy with aspirin and clopidogrel, consistent with cardiovascular studies on CYP2C19 and clopidogrel; however, the bleeding risk that led to early termination of the antiplatelet arm of the SPS3 trial does not appear to be explained by CYP2C19 genotype. This study was relatively underpowered; therefore, these findings should be interpreted with caution and

  10. Building Structure Feature-based Models for Predicting Isoform-specific Human Cytochrome P-450 (hCYP 3A4, 2D6 and 2C9) Inhibition Assay Results in ToxCast

    EPA Science Inventory

    EPA’s ToxCast project is using high-throughput screening (HTS) to profile and prioritize chemicals for further testing. ToxCast Phase I evaluated 309 unique chemicals, the majority pesticide actives, in over 500 HTS assays. These included 3 human cytochrome P450 (hCYP3A4, hCYP2...

  11. Global variation in CYP2C8–CYP2C9 functional haplotypes

    PubMed Central

    Speed, William C; Kang, Soonmo Peter; Tuck, David P; Harris, Lyndsay N; Kidd, Kenneth K

    2009-01-01

    We have studied the global frequency distributions of 10 single nucleotide polymorphisms (SNPs) across 132 kb of CYP2C8 and CYP2C9 in ∼2500 individuals representing 45 populations. Five of the SNPs were in noncoding sequences; the other five involved the more common missense variants (four in CYP2C8, one in CYP2C9) that change amino acids in the gene products. One haplotype containing two CYP2C8 coding variants and one CYP2C9 coding variant reaches an average frequency of 10% in Europe; a set of haplotypes with a different CYP2C8 coding variant reaches 17% in Africa. In both cases these haplotypes are found in other regions of the world at <1%. This considerable geographic variation in haplotype frequencies impacts the interpretation of CYP2C8/CYP2C9 association studies, and has pharmacogenomic implications for drug interactions. PMID:19381162

  12. Impact of CYP2C9 genetic polymorphism on warfarin dose requirements in Pakistani population.

    PubMed

    Siddiqi, Aisha; Khan, Dilshad Ahmad; Khan, Farooq Ahmed; Naveed, Abdul Khaliq

    2010-10-01

    Variations of cytochrome-P450 enzyme system (CYP2CP) are associated with impaired metabolism of warfarin. The objective of our study was to estimate the frequency of genetic and allelic variants of CYP2C9 in Punjabi population of Pakistan and their effects on warfarin dose requirement. One hundred and twenty unrelated Pakistani subjects belong to Punjab province, were randomly included from the registry of National Institute of Heart Disease Rawalpindi, Pakistan. The patients had stable international normalized ratio (INR) of 2 to 3 for last 3 months with warfarin therapy after heart valves replacement. The detection of CYP2C9 variant was done on polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Total 120 patients (73 males; 47 females) of mean age of 37 years participated in the study. Nine patients had mutant allele CYP2C9*3 (7.5%), one CYP2C9*2 (0.8%) and 110 patients exhibited wild type CYP2C9*1 (91.7%). The frequency of CYP2C9 genotype was *1/*1 (0.858) ; *1/*3 (0.117) ; 2/*20 (0.08 ) and *3/*3 (0.017) in our study population. A high dose of warfarin (42.2+9.56) mg/week is required for patients with *1/*1 genotype as compared to patients with *2/*2 (17.5+1.9) and *1/*3 (16.6+2.3) allele (p<0.001). Individuals with CYP2C9*3/3* need lowest (8.75±1.76 mg/week) daily warfarin dose. In conclusion, the genetic variations in the CYP2C9 occur in 14% of Punjabi ethnic group in Pakistan. Presence of CYP2C9*2 or *3 variants is an independent predictor of low warfarin dose requirement in our patients. CYP2C9 variants assay may be used in high risk groups for appropriate dose adjustment to avoid complications on long term basis.

  13. Clinical Utility and Economic Impact of CYP2D6 Genotyping.

    PubMed

    Reynolds, Kristen K; McNally, Beth A; Linder, Mark W

    2016-09-01

    Pharmacogenetics examines an individual's genetic makeup to help predict the safety and efficacy of medications. Practical application optimizes treatment selection to decrease the failure rate of medications and improve clinical outcomes. Lack of efficacy is costly due to adverse drug reactions and increased hospital stays. Cytochrome P450 2D6 (CYP2D6) metabolizes roughly 25% of all drugs. Detecting variants that cause altered CYP2D6 enzymatic activity identifies patients at risk of adverse drug reactions or therapeutic failure with standard dosages of medications metabolized by CYP2D6. This article discusses the clinical application of pharmacogenetics to improve care and decrease costs. PMID:27514466

  14. Genetic polymorphisms of CYP2D6 oxidation in patients with systemic lupus erythematosus

    PubMed Central

    Skrętkowicz, Jadwiga; Barańska, Małgorzata; Kaczorowska, Anna; Rychlik-Sych, Mariola

    2011-01-01

    Introduction Systemic lupus erythematosus (SLE) is a complex, multifactor autoimmune disease. The studies on aetiopathogenesis of autoimmune diseases focus on the impact the genetically conditioned impairment of xenobiotic metabolism may exert. The knowledge of oxidation polymorphism in the course of SLE may be helpful in choosing more efficient and safer therapy. We determined whether there was an association between susceptibility to SLE and particularly to CYP2D6 genotypes. Material and methods The study was carried out in 60 patients with SLE and 129 healthy volunteers and all the subjects were of Polish origin. The samples were analysed for two major defective alles for CYP2D6 – CYP2D6*3 and CYP2D6*4 and one wild -type allele CYP2D6*1-by the polymerase chain reaction fragment length polymorphism (PCR-RFLP) metod with DNA extracted from peripheral blood. Results No statistically significant differences in the incidence of CYP2D6 genotypes between the studied groups were found (p = 0.615). Risk (OR) of SLE development was 1.03 for the carriers of CYP2D6*3 allele and 1.48 for the subjects with CYP2D6*4 allele; but it was not statistically significant. Conclusions Increased occurrence of mutant alleles of the CYP2D6 gene in SLE patients and the calculated OR values could suggest the effect of these mutations on increased SLE development. PMID:22291833

  15. CYP2J2 and CYP2C19 are the major enzymes responsible for metabolism of albendazole and fenbendazole in human liver microsomes and recombinant P450 assay systems.

    PubMed

    Wu, Zhexue; Lee, Doohyun; Joo, Jeongmin; Shin, Jung-Hoon; Kang, Wonku; Oh, Sangtaek; Lee, Do Yup; Lee, Su-Jun; Yea, Sung Su; Lee, Hye Suk; Lee, Taeho; Liu, Kwang-Hyeon

    2013-11-01

    Albendazole and fenbendazole are broad-spectrum anthelmintics that undergo extensive metabolism to form hydroxyl and sulfoxide metabolites. Although CYP3A and flavin-containing monooxygenase have been implicated in sulfoxide metabolite formation, the enzymes responsible for hydroxyl metabolite formation have not been identified. In this study, we used human liver microsomes and recombinant cytochrome P450s (P450s) to characterize the enzymes involved in the formation of hydroxyalbendazole and hydroxyfenbendazole from albendazole and fenbendazole, respectively. Of the 10 recombinant P450s, CYP2J2 and/or CYP2C19 was the predominant enzyme catalyzing the hydroxylation of albendazole and fenbendazole. Albendazole hydroxylation to hydroxyalbendazole is primarily mediated by CYP2J2 (0.34 μl/min/pmol P450, which is a rate 3.9- and 8.1-fold higher than the rates for CYP2C19 and CYP2E1, respectively), whereas CYP2C19 and CYP2J2 contributed to the formation of hydroxyfenbendazole from fenbendazole (2.68 and 1.94 μl/min/pmol P450 for CYP2C19 and CYP2J2, respectively, which are rates 11.7- and 8.4-fold higher than the rate for CYP2D6). Correlation analysis between the known P450 enzyme activities and the rate of hydroxyalbendazole and hydroxyfenbendazole formation in samples from 14 human liver microsomes showed that albendazole hydroxylation correlates with CYP2J2 activity and fenbendazole hydroxylation correlates with CYP2C19 and CYP2J2 activities. These findings were supported by a P450 isoform-selective inhibition study in human liver microsomes. In conclusion, our data for the first time suggest that albendazole hydroxylation is primarily catalyzed by CYP2J2, whereas fenbendazole hydroxylation is preferentially catalyzed by CYP2C19 and CYP2J2. The present data will be useful in understanding the pharmacokinetics and drug interactions of albendazole and fenbendazole in vivo.

  16. Inhibitory effects of fruit juices on cytochrome P450 2C9 activity in vitro.

    PubMed

    Hidaka, Muneaki; Nagata, Masashi; Kawano, Yohei; Sekiya, Hiroshi; Kai, Hirofumi; Yamasaki, Keishi; Okumura, Manabu; Arimori, Kazuhiko

    2008-02-01

    There is limited information on the effect of fruits on human cytochrome P450 (CYP) 2C9 activity. The objective of this study was to determine the effect of fruit juice on CYP2C9-mediated drug metabolism. Nine citrus fruits and eight tropical fruits were chosen. We investigated effects of the fruits on diclofenac 4'-hydroxylation and tolbutamide hydroxylation by human liver microsomes. Among the fruits, pineapple juice showed potent inhibition of CYP2C9 activity. The addition of 25 microl (5.0% v/v) of pineapple juice resulted in almost complete inhibition. Next we examined the inhibitory effect of bromelain, a cysteine protease in pineapple. Bromelain also strongly inhibited CYP2C9 activity. In addition, E-64, a cysteine protease inhibitor, almost entirely blocked inhibition by pineapple juice and bromelain. Thus we found that pineapple juice was a potent inhibitor of CYP2C9, and that the inhibitory effect might be due to the bromelain contained in pineapple.

  17. Re-engineering of CYP2C9 to probe acid-base substrate selectivity.

    PubMed

    Tai, Guoying; Dickmann, Leslie J; Matovic, Nicholas; DeVoss, James J; Gillam, Elizabeth M J; Rettie, Allan E

    2008-10-01

    A common feature of many CYP2C9 ligands is their weak acidity. As revealed by crystallography, the structural basis for this behavior involves a charge-pairing interaction between an anionic moiety on the substrate and an active site R108 residue. In the present study we attempted to re-engineer CYP2C9 to better accept basic ligands by charge reversal at this key residue. We expressed and purified the R108E and R108E/D293N mutants and compared their ability with that of native CYP2C9 to interact with (S)-warfarin, diclofenac, pyrene, propranolol, and ibuprofen amine. As expected, the R108E mutant maintained all the native enzyme's pyrene 1-hydroxylation activity, but catalytic activity toward diclofenac and (S)-warfarin was abrogated. In contrast, the double mutant displayed much less selectivity in its behavior toward these control ligands. Neither of the mutants displayed significant enhancement of propranolol metabolism, and all three preparations exhibited a type II (inhibitor) rather than type I (substrate) spectrum with ibuprofen amine, although binding became progressively weaker with the single and double mutants. Collectively, these data underscore the importance of the amino acid at position 108 in the acid substrate selectivity of CYP2C9, highlight the accommodating nature of the CYP2C9 active site, and provide a cautionary note regarding facile re-engineering of these complex cytochrome P450 active sites.

  18. Impact of CYP2D6 polymorphisms on clinical efficacy and tolerability of metoprolol tartrate.

    PubMed

    Hamadeh, I S; Langaee, T Y; Dwivedi, R; Garcia, S; Burkley, B M; Skaar, T C; Chapman, A B; Gums, J G; Turner, S T; Gong, Y; Cooper-DeHoff, R M; Johnson, J A

    2014-08-01

    Metoprolol is a selective β-1 adrenergic receptor blocker that undergoes extensive metabolism by the polymorphic enzyme cytochrome P450 2D6 (CYP2D6). Our objective was to investigate the influence of CYP2D6 polymorphisms on the efficacy and tolerability of metoprolol tartrate. Two hundred and eighty-one participants with uncomplicated hypertension received 50 mg of metoprolol twice daily followed by response-guided titration to 100 mg twice daily. Phenotypes were assigned based on results of CYP2D6 genotyping and copy number variation assays. Clinical response to metoprolol and adverse effect rates were analyzed in relation to CYP2D6 phenotypes using appropriate statistical tests. Heart rate response differed significantly by CYP2D6 phenotype (P < 0.0001), with poor and intermediate metabolizers showing greater reduction. However, blood pressure response and adverse effect rates were not significantly different by CYP2D6 phenotype. Other than a significant difference in heart rate response, CYP2D6 polymorphisms were not determinants of variability in metoprolol response or tolerability.

  19. Enzyme source effects on CYP2C9 kinetics and inhibition.

    PubMed

    Kumar, Vikas; Rock, Dan A; Warren, Chad J; Tracy, Timothy S; Wahlstrom, Jan L

    2006-11-01

    When choosing a recombinant cytochrome P450 (P450) enzyme system for in vitro studies, it is critical to understand the strengths, limitations, and applicability of the enzyme system to the study design. Although literature kinetic data may be available to assist in enzyme system selection, comparison of data from separate laboratories is often confounded by differences in experimental conditions and bioanalytical techniques. We measured the Michaelis-Menten kinetic parameters for four CYP2C9 substrates (diclofenac, (S)-warfarin, tolbutamide, and (S)-flurbiprofen) using four recombinant CYP2C9 enzyme systems (Supersomes, Baculosomes, RECO system, and in-house purified, reconstituted enzyme) to determine whether the enzyme systems exhibited kinetic differences in metabolic product formation rates under uniform experimental conditions. The purified, reconstituted enzyme systems exhibited higher K(m) values, reduced substrate affinity, and lower calculated intrinsic clearance values compared with baculovirus microsomal preparations. Six- to 25-fold differences in predicted intrinsic clearance values were calculated for each substrate depending on the enzyme system-substrate combination. Results suggest that P450 reductase interactions with the CYP2C9 protein and varying ratios of CYP2C9/P450 reductase in the enzyme preparations may play a role in these observed differences. In addition, when (S)-flurbiprofen was used as a substrate probe to determine CYP2C9 inhibition with a set of 12 inhibitors, decreased inhibition potency was observed across 11 of those inhibitors in the RECO purified, reconstituted enzyme compared with the Supersomes baculovirus microsomal preparation and pooled human liver microsomes. Considering these differences, consistent use of an enzyme source is an important component in producing comparable and reproducible kinetics and inhibition data with CYP2C9. PMID:16928789

  20. Time-Dependent Inhibition of CYP2C19 by Isoquinoline Alkaloids: In Vitro and In Silico Analysis.

    PubMed

    Salminen, Kaisa A; Rahnasto-Rilla, Minna; Väänänen, Raija; Imming, Peter; Meyer, Achim; Horling, Aline; Poso, Antti; Laitinen, Tuomo; Raunio, Hannu; Lahtela-Kakkonen, Maija

    2015-12-01

    The cytochrome P450 2C19 (CYP2C19) enzyme plays an important role in the metabolism of many commonly used drugs. Relatively little is known about CYP2C19 inhibitors, including compounds of natural origin, which could inhibit CYP2C19, potentially causing clinically relevant metabolism-based drug interactions. We evaluated a series (N = 49) of structurally related plant isoquinoline alkaloids for their abilities to interact with CYP2C19 enzyme using in vitro and in silico methods. We examined several common active alkaloids found in herbal products such as apomorphine, berberine, noscapine, and papaverine, as well as the previously identified mechanism-based inactivators bulbocapnine, canadine, and protopine. The IC50 values of the alkaloids ranged from 0.11 to 210 µM, and 42 of the alkaloids were confirmed to be time-dependent inhibitors of CYP2C19. Molecular docking and three-dimensional quantitative structure-activity relationship analysis revealed key interactions of the potent inhibitors with the enzyme active site. We constructed a comparative molecular field analysis model that was able to predict the inhibitory potency of a series of independent test molecules. This study revealed that many of these isoquinoline alkaloids do have the potential to cause clinically relevant drug interactions. These results highlight the need for studying more profoundly the potential interactions between drugs and herbal products. When further refined, in silico methods can be useful in the high-throughput prediction of P450 inhibitory potential of pharmaceutical compounds.

  1. Roles of CYP2C19 Gene Polymorphisms in Susceptibility to POAG and Individual Differences in Drug Treatment Response

    PubMed Central

    Liu, Xiang-Long; Jia, Qiu-Ju; Wang, Li-Na; Liu, Zong-Ming; Liu, Hai; Duan, Xuan-Chu; Lyu, Xue-Man

    2016-01-01

    Background The aim of this study was to investigate the roles of cytochrome P450 2C19 (CYP2C19) polymorphisms in primary open-angle glaucoma (POAG) susceptibility and individual responses to drug treatment. Material/Methods This case-control study consisted of 93 cases with POAG and 125 controls. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to analyze CYP2C19 single-nucleotide polymorphisms (SNPs). After timolol treatment, patients were classified into side effect (SE) group and non-side effect (NSE) group. According to drug treatment responses, patients were divided into 3 groups: excellent group (Ex) (IOP ≥8 mm Hg); utility group (Ut) (5 2C19 between the case group and the control group (both P>0.05). Frequencies of extensive metabolizer phenotype and poor metabolizer phenotype or poor metabolizer phenotype and intermediate metabolizer phenotype were significantly different between the SE group and NSE group (both P<0.05). The distribution of intermediate metabolizer phenotype and extensive metabolizer phenotype were significantly different among Ex group, Ut group, and In group (all P<0.05). Conclusions We found no evidence that CYP2C19 polymorphisms are associated with susceptibility to POAG. However, different CYP2C19 metabolizer phenotypes were identified and observed to have important effects on the individual differences in drug treatment response. PMID:26822491

  2. Mechanism-based inhibition of human liver microsomal cytochrome P450 2D6 (CYP2D6) by alkamides of Piper nigrum.

    PubMed

    Subehan; Usia, Tepy; Kadota, Shigetoshi; Tezuka, Yasuhiro

    2006-05-01

    Nineteen alkamides isolated from Piper nigrum L. were tested for their mechanism-based inhibition on human liver microsomal dextromethorphan O-demethylation activity, a prototype marker for cytochrome P450 2D6 (CYP2D6). All compounds increased their inhibitory activity with increasing preincubation time. Among them, 15 and 17 showed more than 50 % decrease of the CYP2D6 residual activity after 20 min preincubation. Further investigations on 15 and 17 showed that the characteristic time- and concentration-dependent inhibition, which required a catalytic step with NADPH, was not protected by nucleophiles, and was decreased by the presence of a competitive inhibitor. The kinetic parameters for inactivation (kinact and KI) were 0.028 min-1 and 0.23 microM for 15 and 0.064 min-1 and 0.71 microM for 17, respectively, which were stronger than the known mechanism-based inhibitor, paroxetine (a positive control). Thus, 15 and 17 are potent mechanism-based inhibitors of CYP2D6.

  3. Cytochrome P450 2C9 gene polymorphism in phenytoin induced gingival enlargement: A case report.

    PubMed

    Babu, S P K Kennedy; Ramesh, V; Samidorai, Agila; Charles, N S C

    2013-07-01

    Gingival enlargement comprises any clinical condition in which an increase in the size of the gingiva is observed. Among the drugs that induce gingival enlargement, the antiepileptic agent phenytoin has been widely related to this condition. The Cytochrome P450(CYP) superfamily is the most commonly involved enzymes in metabolism of drugs. Common coding region CYP variants that affects drug elimination and response has been studied in great detail. Pharmacogenetic influences on drug metabolism have been widely reviewed and gene polymorphism of cytochrome P450 2C9 appeared to be responsible for much of the interindividual variability on drug elimination. Genetic variation in the CYP2C9 gene can affect metabolism, leading to altered phenotypes. Individuals with poor metaboliser alleles of CYP2C9 gene were shown to have a reduced metabolism of phenytoin compared with wild-type alleles. Thus identification of patients genotype prior to anti-epileptic drug administration could potentially prevent higher serum drug concentrations leading to adverse side effects such as gingival enlargement. This case report addresses the influence of CYP2C9 genetic polymorphism on Phenytoin drug metabolism thereby causing gingival enlargement. PMID:24082701

  4. Structure and Dynamics of the Membrane-Bound Cytochrome P450 2C9

    PubMed Central

    Cojocaru, Vlad; Balali-Mood, Kia; Sansom, Mark S. P.; Wade, Rebecca C.

    2011-01-01

    The microsomal, membrane-bound, human cytochrome P450 (CYP) 2C9 is a liver-specific monooxygenase essential for drug metabolism. CYPs require electron transfer from the membrane-bound CYP reductase (CPR) for catalysis. The structural details and functional relevance of the CYP-membrane interaction are not understood. From multiple coarse grained molecular simulations started with arbitrary configurations of protein-membrane complexes, we found two predominant orientations of CYP2C9 in the membrane, both consistent with experiments and conserved in atomic-resolution simulations. The dynamics of membrane-bound and soluble CYP2C9 revealed correlations between opening and closing of different tunnels from the enzyme's buried active site. The membrane facilitated the opening of a tunnel leading into it by stabilizing the open state of an internal aromatic gate. Other tunnels opened selectively in the simulations of product-bound CYP2C9. We propose that the membrane promotes binding of liposoluble substrates by stabilizing protein conformations with an open access tunnel and provide evidence for selective substrate access and product release routes in mammalian CYPs. The models derived here are suitable for extension to incorporate other CYPs for oligomerization studies or the CYP reductase for studies of the electron transfer mechanism, whereas the modeling procedure is generally applicable to study proteins anchored in the bilayer by a single transmembrane helix. PMID:21852944

  5. Structure and Dynamics of the Membrane-Bound Cytochrome P450 2C9

    SciTech Connect

    Cojocaru, Vlad; Balali-Mood, Kia; Sansom, Mark S.; Wade, Rebecca C.

    2011-08-11

    The microsomal, membrane-bound, human cytochrome P450 (CYP) 2C9 is a liver-specific monooxygenase essential for drug metabolism. CYPs require electron transfer from the membrane-bound CYP reductase (CPR) for catalysis. The structural details and functional relevance of the CYP-membrane interaction are not understood. From multiple coarse grained molecular simulations started with arbitrary configurations of protein-membrane complexes, we found two predominant orientations of CYP2C9 in the membrane, both consistent with experiments and conserved in atomic-resolution simulations. The dynamics of membrane-bound and soluble CYP2C9 revealed correlations between opening and closing of different tunnels from the enzyme’s buried active site. The membrane facilitated the opening of a tunnel leading into it by stabilizing the open state of an internal aromatic gate. Other tunnels opened selectively in the simulations of product-bound CYP2C9. We propose that the membrane promotes binding of liposoluble substrates by stabilizing protein conformations with an open access tunnel and provide evidence for selective substrate access and product release routes in mammalian CYPs. The models derived here are suitable for extension to incorporate other CYPs for oligomerization studies or the CYP reductase for studies of the electron transfer mechanism, whereas the modeling procedure is generally applicable to study proteins anchored in the bilayer by a single transmembrane helix.

  6. MDMA, methamphetamine, and CYP2D6 pharmacogenetics: what is clinically relevant?

    PubMed

    de la Torre, Rafael; Yubero-Lahoz, Samanta; Pardo-Lozano, Ricardo; Farré, Magí

    2012-01-01

    In vitro human studies show that the metabolism of most amphetamine-like psychostimulants is regulated by the polymorphic cytochrome P450 isozyme CYP2D6. Two compounds, methamphetamine and 3,4-methylenedioxymethamphetamine (MDMA), were selected as archetypes to discuss the translation and clinical significance of in vitro to in vivo findings. Both compounds were chosen based on their differential interaction with CYP2D6 and their high abuse prevalence in society. Methamphetamine behaves as both a weak substrate and competitive inhibitor of CYP2D6, while MDMA acts as a high affinity substrate and potent mechanism-based inhibitor (MBI) of the enzyme. The MBI behavior of MDMA on CYP2D6 implies that subjects, irrespective of their genotype/phenotype, are phenocopied to the poor metabolizer (PM) phenotype. The fraction of metabolic clearance regulated by CYP2D6 for both drugs is substantially lower than expected from in vitro studies. Other isoenzymes of cytochrome P450 and a relevant contribution of renal excretion play a part in their clearance. These facts tune down the potential contribution of CYP2D6 polymorphism in the clinical outcomes of both substances. Globally, the clinical relevance of CYP2D6 polymorphism is lower than that predicted by in vitro studies. PMID:23162568

  7. Distribution of CYP2D6 alleles and phenotypes in the Brazilian population.

    PubMed

    Friedrich, Deise C; Genro, Júlia P; Sortica, Vinicius A; Suarez-Kurtz, Guilherme; de Moraes, Maria Elizabete; Pena, Sergio D J; dos Santos, Andrea K Ribeiro; Romano-Silva, Marco A; Hutz, Mara H

    2014-01-01

    The CYP2D6 enzyme is one of the most important members of the cytochrome P450 superfamily. This enzyme metabolizes approximately 25% of currently prescribed medications. The CYP2D6 gene presents a high allele heterogeneity that determines great inter-individual variation. The aim of this study was to evaluate the variability of CYP2D6 alleles, genotypes and predicted phenotypes in Brazilians. Eleven single nucleotide polymorphisms and CYP2D6 duplications/multiplications were genotyped by TaqMan assays in 1020 individuals from North, Northeast, South, and Southeast Brazil. Eighteen CYP2D6 alleles were identified in the Brazilian population. The CYP2D6*1 and CYP2D6*2 alleles were the most frequent and widely distributed in different geographical regions of Brazil. The highest number of CYPD6 alleles observed was six and the frequency of individuals with more than two copies ranged from 6.3% (in Southern Brazil) to 10.2% (Northern Brazil). The analysis of molecular variance showed that CYP2D6 is homogeneously distributed across different Brazilian regions and most of the differences can be attributed to inter-individual differences. The most frequent predicted metabolic status was EM (83.5%). Overall 2.5% and 3.7% of Brazilians were PMs and UMs respectively. Genomic ancestry proportions differ only in the prevalence of intermediate metabolizers. The IM predicted phenotype is associated with a higher proportion of African ancestry and a lower proportion of European ancestry in Brazilians. PM and UM classes did not vary among regions and/or ancestry proportions therefore unique CYP2D6 testing guidelines for Brazilians are possible and could potentially avoid ineffective or adverse events outcomes due to drug prescriptions. PMID:25329392

  8. Distribution of CYP2D6 alleles and phenotypes in the Brazilian population.

    PubMed

    Friedrich, Deise C; Genro, Júlia P; Sortica, Vinicius A; Suarez-Kurtz, Guilherme; de Moraes, Maria Elizabete; Pena, Sergio D J; dos Santos, Andrea K Ribeiro; Romano-Silva, Marco A; Hutz, Mara H

    2014-01-01

    The CYP2D6 enzyme is one of the most important members of the cytochrome P450 superfamily. This enzyme metabolizes approximately 25% of currently prescribed medications. The CYP2D6 gene presents a high allele heterogeneity that determines great inter-individual variation. The aim of this study was to evaluate the variability of CYP2D6 alleles, genotypes and predicted phenotypes in Brazilians. Eleven single nucleotide polymorphisms and CYP2D6 duplications/multiplications were genotyped by TaqMan assays in 1020 individuals from North, Northeast, South, and Southeast Brazil. Eighteen CYP2D6 alleles were identified in the Brazilian population. The CYP2D6*1 and CYP2D6*2 alleles were the most frequent and widely distributed in different geographical regions of Brazil. The highest number of CYPD6 alleles observed was six and the frequency of individuals with more than two copies ranged from 6.3% (in Southern Brazil) to 10.2% (Northern Brazil). The analysis of molecular variance showed that CYP2D6 is homogeneously distributed across different Brazilian regions and most of the differences can be attributed to inter-individual differences. The most frequent predicted metabolic status was EM (83.5%). Overall 2.5% and 3.7% of Brazilians were PMs and UMs respectively. Genomic ancestry proportions differ only in the prevalence of intermediate metabolizers. The IM predicted phenotype is associated with a higher proportion of African ancestry and a lower proportion of European ancestry in Brazilians. PM and UM classes did not vary among regions and/or ancestry proportions therefore unique CYP2D6 testing guidelines for Brazilians are possible and could potentially avoid ineffective or adverse events outcomes due to drug prescriptions.

  9. Distribution of CYP2D6 Alleles and Phenotypes in the Brazilian Population

    PubMed Central

    Sortica, Vinicius A.; Suarez-Kurtz, Guilherme; de Moraes, Maria Elizabete; Pena, Sergio D. J.; dos Santos, Ândrea K. Ribeiro; Romano-Silva, Marco A.; Hutz, Mara H.

    2014-01-01

    Abstract The CYP2D6 enzyme is one of the most important members of the cytochrome P450 superfamily. This enzyme metabolizes approximately 25% of currently prescribed medications. The CYP2D6 gene presents a high allele heterogeneity that determines great inter-individual variation. The aim of this study was to evaluate the variability of CYP2D6 alleles, genotypes and predicted phenotypes in Brazilians. Eleven single nucleotide polymorphisms and CYP2D6 duplications/multiplications were genotyped by TaqMan assays in 1020 individuals from North, Northeast, South, and Southeast Brazil. Eighteen CYP2D6 alleles were identified in the Brazilian population. The CYP2D6*1 and CYP2D6*2 alleles were the most frequent and widely distributed in different geographical regions of Brazil. The highest number of CYPD6 alleles observed was six and the frequency of individuals with more than two copies ranged from 6.3% (in Southern Brazil) to 10.2% (Northern Brazil). The analysis of molecular variance showed that CYP2D6 is homogeneously distributed across different Brazilian regions and most of the differences can be attributed to inter-individual differences. The most frequent predicted metabolic status was EM (83.5%). Overall 2.5% and 3.7% of Brazilians were PMs and UMs respectively. Genomic ancestry proportions differ only in the prevalence of intermediate metabolizers. The IM predicted phenotype is associated with a higher proportion of African ancestry and a lower proportion of European ancestry in Brazilians. PM and UM classes did not vary among regions and/or ancestry proportions therefore unique CYP2D6 testing guidelines for Brazilians are possible and could potentially avoid ineffective or adverse events outcomes due to drug prescriptions. PMID:25329392

  10. Lack of association between schizophrenia and the CYP2D6 gene polymorphisms

    SciTech Connect

    Pirmohamed, M.; Wild, M.J.; Kitteringham, N.R.

    1996-04-09

    Approximately 5-10% of the Caucasian population lack the P450 isoform, CYP2D6. This polymorphism may be of importance in determining individual susceptibility to Parkinson`s disease. In this journal, Daniels et al. recently reported a negative association between the CYP2D6 gene locus and schizophrenia, a disease characterized by dopamine overactivity. It is important to exclude such an association because CYP2D6 is expressed in the brain and it is involved in dopamine catabolism. Between 1992 and 1993, we also performed a study similar to that, and reached the same conclusion. 7 refs., 1 tab.

  11. A discordance of the cytochrome P450 2C19 genotype and phenotype in patients with advanced cancer

    PubMed Central

    Williams, Marion L; Bhargava, Pankaj; Cherrouk, Ilham; Marshall, John L; Flockhart, David A; Wainer, Irving W

    2000-01-01

    Aims To examine the relationship between cytochrome P450 2C19 (CYP2C19) genotype and expressed metabolic activity in 16 patients with advanced metastatic cancer. Methods Individual CYP2C19 genotypes were determined by PCR-based amplification, followed by restriction fragment length analysis, and compared with observed CYP2C19 metabolic activity, as determined using the log hydroxylation index of omeprazole. Results All 16 patients had an extensive metabolizer genotype. However, based on the antimode in a distribution of log omeprazole hydroxylation indices from healthy volunteers, four of the patients had a poor metabolizer phenotype and there was a general shift of the remaining 12 patients towards a slower metabolic phenotype. This suggests a reduction in metabolic activity for all patients relative to healthy volunteers. A careful analysis of patient medical records failed to reveal any drug interactions or other source for the observed discordance between genotype and phenotype. Conclusions There are no previous reports of a ‘discordance’ between genotype and expressed enzyme activity in cancer patients. Such a decrease in enzyme activity could have an impact on the efficacy and toxicity of chemotherapeutic agents and other drugs, used in standard oncology practice. PMID:10792207

  12. CYP2D6 allele distribution in Macedonians, Albanians and Romanies in the Republic of Macedonia

    PubMed Central

    Kuzmanovska, M; Dimishkovska, M; Maleva Kostovska, I; Noveski, P; Sukarova Stefanovska, E

    2015-01-01

    Abstract Cytochrome P450 2D6 (CYP2D6) is an enzyme of great importance for the metabolism of clinically used drugs. More than 100 variants of the CYP2D6 gene have been identified so far. The aim of this study was to investigate the allele distribution of CYP2D6 gene variants in 100 individuals of each of the Macedonian, Albanian and Romany population, by genotyping using long range polymerase chain reaction (PCR) and a multiplex single base extension method. The most frequent variants and almost equally distributed in the three groups were the fully functional alleles *1 and *2. The most common non functional allele in all groups was *4 that was found in 22.5% of the Albanians. The most common allele with decreased activity was *41 which was found in 23.0% of the Romany ethnic group, in 11.0% of the Macedonians and in 10.5% of the Albanians. Seven percent of the Albanians, 6.0% of the Romani and 4.0% of the Macedonians were poor metabolizers, while 5.0% of the Macedonians, 1.0% of Albanians and 1.0% of the Romanies were ultrarapid metabolizers. We concluded that the CYP2D6 gene locus is highly heterogeneous in these groups and that the prevalence of the CYP2D6 allele variants and genotypes in the Republic of Macedonia is in accordance with that of other European populations.

  13. Effect of CYP2D6 genetic polymorphism on the metabolism of citalopram in vitro.

    PubMed

    Hu, Xiao-Xia; Yuan, Ling-Jing; Fang, Ping; Mao, Yong-Hui; Zhan, Yun-Yun; Li, Xiang-Yu; Dai, Da-Peng; Cai, Jian-Ping; Hu, Guo-Xin

    2016-04-01

    Genetic polymorphisms of CYP2D6 significantly influence the efficacy and safety of some drugs, which might cause adverse effects and therapeutic failure. We aimed at investigating the role of CYP2D6 in the metabolism of citalopram and identifying the effect of 24 CYP2D6 allelic variants we found in Chinese Han population on the metabolism of citalopram in vitro. These CYP2D6 variants expressed by insect cells system were incubated with 10-1000 μM citalopram for 30 min at 37 °C and the reaction was terminated by cooling to -80 °C immediately. Citalopram and its metabolites were analyzed by high-performance liquid chromatography (HPLC). The intrinsic clearance (Vmax/Km) values of the variants toward citalopram metabolites were significantly altered, 38-129% for demethylcitalopram and 13-138% for citalopram N-oxide when compared with CYP2D6*1. Most of the tested rare alleles exhibited significantly decreased values due to increased Km and/or decreased Vmax values. We conclude that recombinant system could be used to investigate the enzymes involved in drug metabolism and these findings suggest that more attention should be paid to subjects carrying these CYP2D6 alleles when administering citalopram in the clinic. PMID:27016952

  14. CYP2C9 Mutation Affecting the Individual Variability of Warfarin Dose Requirement.

    PubMed

    Kim, Young Bum; Ko, Moon Ju; Lee, Dae Gu; Do, Jong Gul; Hwang, Ji Hye

    2012-12-01

    Warfarin is a frequently prescribed anticoagulant in rehabilitation patients. Adverse drug reactions of warfarin were reported as bleeding and cutaneous microvascular thrombosis. Major bleeding, such as intracranial hemorrhage and psoas hematoma, in patients receiving anticoagulation therapy is a rare condition, but sometimes very serious complication that can even be fatal. Patient-specific factors (eg, age, body size, race, concurrent diseases, and medications) explain some of the individual variability in warfarin dose, but genetic factors, which influence warfarin response, explain a significantly higher proportion of the variability in the dose. There are two identified genes that are responsible for the main proportion of the genetic effect: CYP2C9, which codes for the enzyme cytochrome P450 2C9 that metabolizes S-warfarin, and VKORC1, which codes for warfarin's target, vitamin K epoxide reductase. We report a case of intolerance to warfarin dosing, due to impaired drug metabolism in a patient with CYP2C9(*)1/(*)3 and VKORC 1173TT. Fortunately, there are no severe complications.

  15. Simultaneous Two-Vessel Subacute Stent Thrombosis Caused by Clopidogrel Resistance from CYP2C19 Polymorphism.

    PubMed

    Afzal, Ashwad; Patel, Bimal; Patel, Neel; Sattur, Sudhakar; Patel, Vinod

    2016-01-01

    Clopidogrel resistance from CYP2C19 polymorphism has been associated with stent thrombosis in patients undergoing percutaneous coronary intervention with drug-eluting stents. We present a case of a 76-year-old male who received drug-eluting stents to the right coronary artery and left anterior descending artery for non-ST elevation myocardial infarction and was discharged on dual antiplatelet therapy with aspirin and clopidogrel. He subsequently presented with chest pain from anterior, anteroseptal, and inferior ST segment elevation myocardial infarction. An emergent coronary angiogram revealed acute stent thrombosis with 100% occlusion of RCA and LAD that was successfully treated with thrombus aspiration and angioplasty. Although he was compliant with his dual antiplatelet therapy, he developed stent thrombosis, which was confirmed as clopidogrel resistance from homozygous CYP2C19 polymorphism. PMID:27555873

  16. Simultaneous Two-Vessel Subacute Stent Thrombosis Caused by Clopidogrel Resistance from CYP2C19 Polymorphism

    PubMed Central

    Patel, Bimal; Patel, Neel; Sattur, Sudhakar; Patel, Vinod

    2016-01-01

    Clopidogrel resistance from CYP2C19 polymorphism has been associated with stent thrombosis in patients undergoing percutaneous coronary intervention with drug-eluting stents. We present a case of a 76-year-old male who received drug-eluting stents to the right coronary artery and left anterior descending artery for non-ST elevation myocardial infarction and was discharged on dual antiplatelet therapy with aspirin and clopidogrel. He subsequently presented with chest pain from anterior, anteroseptal, and inferior ST segment elevation myocardial infarction. An emergent coronary angiogram revealed acute stent thrombosis with 100% occlusion of RCA and LAD that was successfully treated with thrombus aspiration and angioplasty. Although he was compliant with his dual antiplatelet therapy, he developed stent thrombosis, which was confirmed as clopidogrel resistance from homozygous CYP2C19 polymorphism. PMID:27555873

  17. Impact of cytochrome P450 2C19 polymorphisms on the pharmacokinetics of tacrolimus when coadministered with voriconazole

    PubMed Central

    Imamura, Chiyo K.; Furihata, Kenichi; Okamoto, Shinichiro

    2015-01-01

    Abstract This study evaluated the effects of cytochrome P450 (CYP) 2C19 polymorphisms on tacrolimus pharmacokinetics when coadministered with voriconazole. Eighteen healthy volunteers, including 6 individuals in each CYP2C19 genotype (extensive metabolizers [EMs], intermediate metabolizers [IMs], and poor metabolizers [PMs]), received a single oral dose of 3 mg tacrolimus alone or in combination with 200 mg voriconazole twice daily at steady state. When tacrolimus was coadministered with voriconazole, a significant increase in area under its concentration‐time curve (AUC0‐24) was observed for all genotypes. AUC0‐12 of voriconazole in IMs and PMs were significantly higher than that in EMs (P < .05 and P < .01, respectively). Consequently, AUC0‐24 of tacrolimus in combination with voriconazole in IMs and PMs were also significantly higher than that in EMs (P < .05). These results demonstrate that CYP2C19 genotypes influenced the exposure of tacrolimus when coadministered with voriconazole, although tacrolimus is mainly metabolized by CYP3A. PMID:26239045

  18. Positive clinical response to clopidogrel is independent of paraoxonase 1 Q192R and CYP2C19 genetic variants.

    PubMed

    Martínez-Quintana, Efrén; Medina-Gil, José M; Rodríguez-González, Fayna; Garay-Sánchez, Paloma; Limiñana, José M; Saavedra, Pedro; Tugores, Antonio

    2014-08-01

    There is increasing controversy about the influence of serum paraoxonase type 1 and cytochrome CYP2C19 in the conversion of clopidogrel to its pharmaceutically active metabolite. The effect of concomitant medication with the proton pump inhibitor omeprazole has been also subject of intense scrutiny. We present a cohort of 263 patients receiving anti-platelet aggregation treatment with clopidogrel and aspirin for 1 year. The paraoxonase 1 gene Q192R variant along with the presence of CYP2C19*2 and *3 loss of function alleles, concomitant medication with proton pump inhibitors and known cardiovascular risk factors were examined to determine their influence in disease relapse due to an ischaemic event during the 12 month treatment period. The low number of patients suffering a relapse (20 out of 263), indicates that double anti-aggregation therapy with aspirin and clopidogrel was very effective in our patients. Among the relapsers, evidence of coronary heart disease was the most influencial factor affecting response to therapy, while the presence of the paraoxonase 1 Q192R variant, loss of function of CYP2C19, and concomitant medication with omeprazole were non-significant. PMID:24504666

  19. Clinical Pharmacogenetics Implementation Consortium Guidelines for Cytochrome P450 2D6 Genotype and Codeine Therapy: 2014 Update

    PubMed Central

    Crews, K R; Gaedigk, A; Dunnenberger, H M; Leeder, J S; Klein, T E; Caudle, K E; Haidar, C E; Shen, D D; Callaghan, J T; Sadhasivam, S; Prows, C A; Kharasch, E D; Skaar, T C

    2014-01-01

    Codeine is bioactivated to morphine, a strong opioid agonist, by the hepatic cytochrome P450 2D6 (CYP2D6); hence, the efficacy and safety of codeine are governed by CYP2D6 activity. Polymorphisms are a major cause of CYP2D6 variability. We summarize evidence from the literature supporting this association and provide therapeutic recommendations for codeine based on CYP2D6 genotype. This document is an update to the 2012 Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines for CYP2D6 genotype and codeine therapy. PMID:24458010

  20. Cytochrome P450 2D6 Activity Predicts Discontinuation of Tamoxifen Therapy in Breast Cancer Patients

    PubMed Central

    Rae, James M.; Sikora, Matthew J.; Henry, N. Lynn; Li, Lang; Kim, Seongho; Oesterreich, Steffi; Skaar, Todd; Nguyen, Anne T.; Desta, Zeruesenay; Storniolo, Anna Maria; Flockhart, David A.; Hayes, Daniel F.; Stearns, Vered

    2009-01-01

    The selective estrogen receptor modulator tamoxifen is routinely used for treatment and prevention of estrogen receptor positive breast cancer. Studies of tamoxifen adherence suggest that over half of patients discontinue treatment before the recommended 5 years. We hypothesized that polymorphisms in CYP2D6, the enzyme responsible for tamoxifen activation, predict for tamoxifen discontinuation. Tamoxifen-treated women (n = 297) were genotyped for CYP2D6 variants and assigned a “score” based on predicted allele activities from 0 (no activity) to 2 (high activity). Correlation between CYP2D6 score and discontinuation rates at 4 months were tested. We observed a strong non-linear correlation between higher CYP2D6 score and increased rates of discontinuation (r2 = 0.935, p = 0.018). These data suggest that presence of active CYP2D6 alleles may predict for higher likelihood of tamoxifen discontinuation. Therefore, patients who may be most likely to benefit from tamoxifen may paradoxically be most likely to discontinue treatment prematurely. PMID:19421167

  1. CYP2D6 polymorphism and mental and personality disorders in suicide attempters.

    PubMed

    Blasco-Fontecilla, Hilario; Peñas-Lledó, Eva; Vaquero-Lorenzo, Concepción; Dorado, Pedro; Saiz-Ruiz, Jerónimo; Llerena, Adrián; Baca-García, Enrique

    2014-12-01

    Prior studies on the association between the CYP2D6 polymorphism and suicide did not explore whether mental and personality disorders mediate this association. The main objective of the present study was to test an association between CYP2D6 polymorphism and mental and personality disorders among suicide attempters. The MINI and the DSM-IV version of the International Personality Disorder Examination Screening Questionnaire were used to diagnose mental and personality disorders, respectively, in 342 suicide attempters. Suicide attempters were divided into four groups according to their number of CYP2D6 active genes (zero, one, and two or more). Differences in mental and personality disorders across the four groups were measured using linear-by-linear association, chi square-test, and 95% confidence intervals. Suicide attempters carrying two or more active CYP2D6 genes were more likely to be diagnosed with at least one personality disorder than those with one or zero CYP2D6 active genes.

  2. CYP2D6 Genotyping and Tamoxifen: An Unfinished Story in the Quest for Personalized Medicine

    PubMed Central

    de Souza, Jonas A.; Olopade, Olufunmilayo I.

    2011-01-01

    The philosophy behind personalized medicine is that each patient has a unique biologic profile that should guide the choice of therapy, resulting in an improved treatment outcome, ideally with reduced toxicity. Thus, there has been increasing interest in identifying genetic variations that are predictive of a drug’s efficacy or toxicity. Although it is one of the most effective drugs for treating breast cancer, tamoxifen is not effective in all estrogen receptor (ER)-positive breast cancer patients, and it is frequently associated with side effects, such as hot flashes. Relative resistance to tamoxifen treatment may be a result, in part, from impaired drug activation by cytochrome P450 2D6 (CYP2D6). Indeed, recent studies have identified allelic variations in CYP2D6 to be an important determinant of tamoxifen’s activity (and toxicity). This article will summarize the current information regarding the influence of the major genotypes and CYP2D6 inhibitors on tamoxifen metabolism, with a focus on its clinical utility and the current level of evidence for CYP2D6 genotyping of patients who are candidates for tamoxifen treatment. PMID:21421116

  3. Effects of CYP2C9*1/*3 genotype on the pharmacokinetics of flurbiprofen in Korean subjects.

    PubMed

    Lee, Yun-Jeong; Byeon, Ji-Yeong; Kim, Young-Hoon; Kim, Se-Hyung; Choi, Chang-Ik; Bae, Jung-Woo; Sohn, Uy-Dong; Jang, Choon-Gon; Lee, Jeongmi; Lee, Seok-Yong

    2015-06-01

    The aim of this study was to investigate the impact of CYP2C9*1/*3 genotype on the pharmacokinetics of flurbiprofen and its metabolite. The CYP2C9 genotypes were determined with the use of polymerase chain reaction and restriction fragment and DNA sequencing analysis in 358 healthy Koreans. Among them, twenty individuals with CYP2C9*1/*1 (n = 12) or CYP2C9*1/*3 (n = 8) genotypes received a single 40 mg oral dose of flurbiprofen. The plasma concentrations of flurbiprofen and its metabolite, 4'-hydroxyflurbiprofen were measured by HPLC. AUCinf of flurbiprofen was significantly higher and its clearance was significantly lower in the CYP2C9*1/*3 individuals than in those with CYP2C9*1/*1. The AUC ratio of 4'-hydroxyflurbiprofen to flurbiprofen was significantly lower in the CYP2C9*1/*3 individuals than in those with CYP2C9*1/*1. These results indicate that the individuals carrying of CYP2C9*3 have significant reduction in flurbiprofen metabolism. The clinical use of this information may allow for more efficient personalized pharmacotherapy.

  4. Farnesoid X Receptor Agonist Represses Cytochrome P450 2D6 Expression by Upregulating Small Heterodimer Partner.

    PubMed

    Pan, Xian; Lee, Yoon-Kwang; Jeong, Hyunyoung

    2015-07-01

    Cytochrome P450 2D6 (CYP2D6) is a major drug-metabolizing enzyme responsible for eliminating approximately 20% of marketed drugs. Studies have shown that differential transcriptional regulation of CYP2D6 may contribute to large interindividual variability in CYP2D6-mediated drug metabolism. However, the factors governing CYP2D6 transcription are largely unknown. We previously demonstrated small heterodimer partner (SHP) as a novel transcriptional repressor of CYP2D6 expression. SHP is a representative target gene of the farnesoid X receptor (FXR). The objective of this study is to investigate whether an agonist of FXR, 3-(2,6-dichlorophenyl)-4-(3'-carboxy-2-chlorostilben-4-yl)oxymethyl-5-isopropylisoxazole (GW4064), alters CYP2D6 expression and activity. In CYP2D6-humanized transgenic mice, GW4064 decreased hepatic CYP2D6 expression and activity (by 2-fold) while increasing SHP expression (by 2-fold) and SHP recruitment to the CYP2D6 promoter. CYP2D6 repression by GW4064 was abrogated in Shp(-/-);CYP2D6 mice, indicating a critical role of SHP in CYP2D6 regulation by GW4064. Also, GW4064 decreased CYP2D6 expression (by 2-fold) in primary human hepatocytes, suggesting that the results obtained in CYP2D6-humanized transgenic mice can be translated to humans. This proof of concept study provides evidence for CYP2D6 regulation by an inducer of SHP expression, namely, the FXR agonist GW4064.

  5. Farnesoid X Receptor Agonist Represses Cytochrome P450 2D6 Expression by Upregulating Small Heterodimer Partner

    PubMed Central

    Pan, Xian; Lee, Yoon-Kwang

    2015-01-01

    Cytochrome P450 2D6 (CYP2D6) is a major drug-metabolizing enzyme responsible for eliminating approximately 20% of marketed drugs. Studies have shown that differential transcriptional regulation of CYP2D6 may contribute to large interindividual variability in CYP2D6-mediated drug metabolism. However, the factors governing CYP2D6 transcription are largely unknown. We previously demonstrated small heterodimer partner (SHP) as a novel transcriptional repressor of CYP2D6 expression. SHP is a representative target gene of the farnesoid X receptor (FXR). The objective of this study is to investigate whether an agonist of FXR, 3-(2,6-dichlorophenyl)-4-(3′-carboxy-2-chlorostilben-4-yl)oxymethyl-5-isopropylisoxazole (GW4064), alters CYP2D6 expression and activity. In CYP2D6-humanized transgenic mice, GW4064 decreased hepatic CYP2D6 expression and activity (by 2-fold) while increasing SHP expression (by 2-fold) and SHP recruitment to the CYP2D6 promoter. CYP2D6 repression by GW4064 was abrogated in Shp(−/−);CYP2D6 mice, indicating a critical role of SHP in CYP2D6 regulation by GW4064. Also, GW4064 decreased CYP2D6 expression (by 2-fold) in primary human hepatocytes, suggesting that the results obtained in CYP2D6-humanized transgenic mice can be translated to humans. This proof of concept study provides evidence for CYP2D6 regulation by an inducer of SHP expression, namely, the FXR agonist GW4064. PMID:25926433

  6. Influence of admixture components on CYP2C9*2 allele frequency in eight indigenous populations from Northwest Mexico.

    PubMed

    Sosa-Macías, M; Lazalde-Ramos, B P; Galaviz-Hernández, C; Rangel-Villalobos, H; Salazar-Flores, J; Martínez-Sevilla, V M; Martínez-Fierro, M L; Dorado, P; Wong, M L; Licinio, J; LLerena, A

    2013-12-01

    We previously documented the lowest frequency of CYP2C9*2 in Mexican indigenous Tepehuanos followed by Mestizos and Mexican-Americans populations, suggesting a negative correlation between the CYP2C9*2 frequency and the degree of Asian ancestry in indigenous Americans. We determined the influence of ethnic admixture components on the CYP2C9 allele distribution in 505 Amerindian from eight indigenous populations through genotyping CYP2C9*2, *3 and *6 alleles by real-time PCR and molecular evaluation of ancestry. The frequencies for CYP2C9*2 were 0.026 in Seris and 0.057 in Mayos, being higher than in Asians (P<0.001). CYP2C9*3 was found in Tarahumaras (0.104), Mayos (0.091), Tepehuanos (0.075), Guarijíos (0.067), Huicholes (0.033) and Coras (0.037), with East Asians having lower frequencies than the former three groups (P<0.001). CYP2C9*6 was not found. The frequency of CYP2C9*2 was lower in Amerindians than in European populations, and higher than their Asian ancestors. The presence of this allele in ethnic groups in Mexico can be explained by European admixture.

  7. Genotype-Phenotype Analysis of CYP2C19 in Healthy Saudi Individuals and its Potential Clinical Implication in Drug Therapy

    PubMed Central

    Saeed, Leena H; Mayet, Ahmed Y

    2013-01-01

    CYP2C19 is a cytochrome P450 enzyme, which is involved in the metabolism of some clinically important medications and is encoded by a highly polymorphic gene. There is no available data on the distribution of the CYP2C19 *4 and *17 mutant alleles in the Saudi Arabian population. The aim of the study was to determine different CYP2C19 mutant allele (*2, *4 and *17) frequencies in healthy Saudi subjects and to determine genotype frequencies for these mutations. The CYP2C19 genotypes were then classified into phenotypes. Result: In 201 adults of Saudi ethnicity, the allele frequencies were CYP2C19*1 (62.9%), *17 (25.7%), *2 (11.2%) and *4 (0.2%). The most prevalent genotype combinations were CYP2C19 *1/*1 (40.3%) and *1/*17 (30.4%). The distribution of CYP2C19 phenotypes was divided into extensive metabolizers (EM) 77.6%, intermediate metabolizers (IM) 14.9%, ultra-rapid metabolizers (UM) 7% and poor metabolizers (PM) 0.4%. This finding has important clinical implications for the use of CYP2C19 metabolized medications in the Saudi population and further studies are needed. PMID:24046523

  8. Genomics of Dementia: APOE- and CYP2D6-Related Pharmacogenetics

    PubMed Central

    Cacabelos, Ramón; Martínez, Rocío; Fernández-Novoa, Lucía; Carril, Juan C.; Lombardi, Valter; Carrera, Iván; Corzo, Lola; Tellado, Iván; Leszek, Jerzy; McKay, Adam; Takeda, Masatoshi

    2012-01-01

    Dementia is a major problem of health in developed societies. Alzheimer's disease (AD), vascular dementia, and mixed dementia account for over 90% of the most prevalent forms of dementia. Both genetic and environmental factors are determinant for the phenotypic expression of dementia. AD is a complex disorder in which many different gene clusters may be involved. Most genes screened to date belong to different proteomic and metabolomic pathways potentially affecting AD pathogenesis. The ε4 variant of the APOE gene seems to be a major risk factor for both degenerative and vascular dementia. Metabolic factors, cerebrovascular disorders, and epigenetic phenomena also contribute to neurodegeneration. Five categories of genes are mainly involved in pharmacogenomics: genes associated with disease pathogenesis, genes associated with the mechanism of action of a particular drug, genes associated with phase I and phase II metabolic reactions, genes associated with transporters, and pleiotropic genes and/or genes associated with concomitant pathologies. The APOE and CYP2D6 genes have been extensively studied in AD. The therapeutic response to conventional drugs in patients with AD is genotype specific, with CYP2D6-PMs, CYP2D6-UMs, and APOE-4/4 carriers acting as the worst responders. APOE and CYP2D6 may cooperate, as pleiotropic genes, in the metabolism of drugs and hepatic function. The introduction of pharmacogenetic procedures into AD pharmacological treatment may help to optimize therapeutics. PMID:22482072

  9. Evaluation of a [13C]-Dextromethorphan Breath Test to Assess CYP2D6 Phenotype

    PubMed Central

    Leeder, J. Steven; Pearce, Robin E.; Gaedigk, Andrea; Modak, Anil; Rosen, David I.

    2016-01-01

    A [13C]-dextromethorphan ([13C]-DM) breath test was evaluated to assess its feasibility as a rapid, phenotyping assay for CYP2D6 activity. [13C]-DM (0.5 mg/kg) was administered orally with water or potassium bicarbonate-sodium bicarbonate to 30 adult Caucasian volunteers (n = 1 each): CYP2D6 poor metabolizers (2 null alleles; PM-0) and extensive metabolizers with 1 (EM-1) or 2 functional alleles (EM-2). CYP2D6 phenotype was determined by 13CO2 enrichment measured by infrared spectrometry (delta-over-baseline [DOB] value) in expired breath samples collected before and up to 240 minutes after [13C]-DM ingestion and by 4-hour urinary metabolite ratio. The PM-0 group was readily distinguishable from either EM group by both the breath test and urinary metabolite ratio. Using a single point determination of phenotype at 40 minutes and defining PMs as subjects with a DOB ≤ 0.5, the sensitivity of the method was 100%; specificity was 95% with 95% accuracy and resulted in the misclassification of 1 EM-1 individual as a PM. Modification of the initial protocol (timing of potassium bicarbonate-sodium bicarbonate administration relative to dose) yielded comparable results, but there was a tendency toward increased DOB values. Although further development is required, these studies suggest that the [13C]-DM breath test offers promise as a rapid, minimally invasive phenotyping assay for CYP2D6 activity. PMID:18728242

  10. Predicting CYP2C19 catalytic parameters for enantioselective oxidations using artificial neural networks and a chirality code.

    PubMed

    Hartman, Jessica H; Cothren, Steven D; Park, Sun-Ha; Yun, Chul-Ho; Darsey, Jerry A; Miller, Grover P

    2013-07-01

    Cytochromes P450 (CYP for isoforms) play a central role in biological processes especially metabolism of chiral molecules; thus, development of computational methods to predict parameters for chiral reactions is important for advancing this field. In this study, we identified the most optimal artificial neural networks using conformation-independent chirality codes to predict CYP2C19 catalytic parameters for enantioselective reactions. Optimization of the neural networks required identifying the most suitable representation of structure among a diverse array of training substrates, normalizing distribution of the corresponding catalytic parameters (k(cat), K(m), and k(cat)/K(m)), and determining the best topology for networks to make predictions. Among different structural descriptors, the use of partial atomic charges according to the CHelpG scheme and inclusion of hydrogens yielded the most optimal artificial neural networks. Their training also required resolution of poorly distributed output catalytic parameters using a Box-Cox transformation. End point leave-one-out cross correlations of the best neural networks revealed that predictions for individual catalytic parameters (k(cat) and K(m)) were more consistent with experimental values than those for catalytic efficiency (k(cat)/K(m)). Lastly, neural networks predicted correctly enantioselectivity and comparable catalytic parameters measured in this study for previously uncharacterized CYP2C19 substrates, R- and S-propranolol. Taken together, these seminal computational studies for CYP2C19 are the first to predict all catalytic parameters for enantioselective reactions using artificial neural networks and thus provide a foundation for expanding the prediction of cytochrome P450 reactions to chiral drugs, pollutants, and other biologically active compounds.

  11. Lansoprazole Is Associated with Worsening Asthma Control in Children with the CYP2C19 Poor Metabolizer Phenotype

    PubMed Central

    Holbrook, Janet T.; Mougey, Edward B.; Wei, Christine Y.; Wise, Robert A.; Teague, W. Gerald; Lima, John J.

    2015-01-01

    Rationale: Gastric acid blockade in children with asymptomatic acid reflux has not improved asthma control in published studies. There is substantial population variability regarding metabolism of and response to proton pump inhibitors based on metabolizer phenotype. How metabolizer phenotype affects asthma responses to acid blockage is not known. Objectives: To determine how metabolizer phenotype based on genetic analysis of CYP2C19 affects asthma control among children treated with a proton pump inhibitor. Methods: Asthma control as measured by the Asthma Control Questionnaire (ACQ) and other questionnaires from a 6-month clinical trial of lansoprazole in children with asthma was analyzed for associations with surrogates of lansoprazole exposure (based on treatment assignment and metabolizer phenotype). Groups included placebo-treated children; lansoprazole-treated extensive metabolizers (EMs); and lansoprazole-treated poor metabolizers (PMs). Metabolizer phenotypes were based on CYP2C19 haplotypes. Carriers of the CYP2C19*2, *3, *8, *9, or *10 allele were PMs; carriers of two wild-type alleles were extensive metabolizers (EMs). Measurements and Main Results: Asthma control through most of the treatment period was unaffected by lansoprazole exposure or metabolizer phenotype. At 6 months, PMs displayed significantly worsened asthma control compared with EMs (+0.16 vs. –0.13; P = 0.02) and placebo-treated children (+0.16 vs. –0.23; P < 0.01). Differences in asthma control were not associated with changes in gastroesophageal reflux symptoms. Recent upper respiratory infection worsened asthma control, and this upper respiratory infection effect may be more pronounced among lansoprazole-treated PMs. Conclusions: Children with the PM phenotype developed worse asthma control after 6 months of lansoprazole treatment for poorly controlled asthma. Increased exposure to proton pump inhibitor may worsen asthma control by altering responses to respiratory

  12. Clinical inhibition of CYP2D6-catalysed metabolism by the antianginal agent perhexiline

    PubMed Central

    Davies, Benjamin J L; Coller, Janet K; James, Heather M; Gillis, David; Somogyi, Andrew A; Horowitz, John D; Morris, Raymond G; Sallustio, Benedetta C

    2004-01-01

    Aims Perhexiline is an antianginal agent that displays both saturable and polymorphic metabolism via CYP2D6. The aim of this study was to determine whether perhexiline produces clinically significant inhibition of CYP2D6-catalysed metabolism in angina patients. Methods The effects of perhexiline on CYP2D6-catalysed metabolism were investigated by comparing urinary total dextrorphan/dextromethorphan metabolic ratios following a single dose of dextromethorphan (16.4 mg) in eight matched control patients not taking perhexiline and 24 patients taking perhexiline. All of the patients taking perhexiline had blood drawn for CYP2D6 genotyping as well as to measure plasma perhexiline and cis-OH-perhexiline concentrations. Results Median (range) dextrorphan/dextromethorphan metabolic ratios were significantly higher (P < 0.0001) in control patients, 271.1 (40.3–686.1), compared with perhexiline-treated patients, 5.0 (0.3–107.9). In the perhexiline-treated group 10/24 patients had metabolic ratios consistent with poor metabolizer phenotypes; however, none was a genotypic poor metabolizer. Interestingly, 89% of patients who had phenocopied to poor metabolizers had only one functional CYP2D6 gene. There was a significant negative linear correlation between the log of the dextrorphan/dextromethorphan metabolic ratio and plasma perhexiline concentrations (r2 = 0.69, P < 0.0001). Compared with patients with at least two functional CYP2D6 genes, those with one functional gene were on similar perhexiline dosage regimens but had significantly higher plasma perhexiline concentrations, 0.73 (0.21–1.00) vs. 0.36 (0.04–0.69) mg l−1 (P = 0.04), lower cis-OH-perhexiline/perhexiline ratios, 2.85 (0.35–6.10) vs. 6.51 (1.84–11.67) (P = 0.03), and lower dextrorphan/dextromethorphan metabolic ratios, 2.51 (0.33–39.56) vs. 11.80 (2.90–36.93) (P = 0.005). Conclusions Perhexiline significantly inhibits CYP2D6-catalysed metabolism in angina patients. The plasma cis

  13. Quantitative Assessment of the Effect of Cytochrome P450 2C9 Gene Polymorphism and Colorectal Cancer

    PubMed Central

    Zhang, Liang; Wang, Yichao; Ma, Yushui; Zhang, Feng; Fu, Da; Wang, Xiaofeng

    2013-01-01

    CYP2C9 enzyme activity is involved in the metabolism of substances related to colorectal cancer (CRC), and it is functionally linked to a genetic polymorphism. Two allelic variants of the CYP2C9 gene, namely CYP2C9*2 and CYP2C9*3, differ from wild-type CYP2C9*1 by single amino acid substitutions. These mutated alleles encode enzymes with altered properties that are associated with impaired metabolism. In the past decade, a number of case-control studies have been carried out to investigate the relationship between the CYP2C9 polymorphism and CRC susceptibility, but the results were conflicting. To investigate this inconsistency, we performed a meta-analysis of 13 studies involving a total of 20,879 subjects for CYP2C9*2 and *3 polymorphisms to evaluate the effect of CYP2C9 on genetic susceptibility for CRC. Overall, the summary odds ratio of CRC was 0.94 (95%CI: 0.87–1.03, P = 0.18) and 1.00 (95%CI: 0.86–1.16, P = 0.99) for CYP2C9 *2 and *3 carriers, respectively. No significant results were observed in heterozygous and homozygous when compared with wild genotype for these polymorphisms. In the stratified analyses according to ethnicity, sample size, diagnostic criterion, HWE status and sex, no evidence of any gene-disease association was obtained. Our result suggest that the *2, *3 polymorphisms of CYP2C9 gene are not associated with CRC susceptibility. PMID:23577132

  14. The CYP2D6 extensive metabolizer genotype is associated with increased risk for bladder cancer.

    PubMed

    Abdel-Rahman, S Z; Anwar, W A; Abdel-Aal, W E; Ghoneim, M A; Au, W W

    1997-10-28

    Inheritance of certain polymorphic metabolizing genes is associated with the development of a number of environmental cancers and may also influence the clinicopathological tumor outcome. We have investigated the association between the inheritance of the polymorphic cytochrome P-450 2D6 (CYP2D6) gene and the development of transitional and squamous cell carcinomas (TCC and SCC) of the bladder in 37 Egyptian cancer patients and 27 matched controls. Genotypic analysis using the polymerase chain reaction (PCR) and the restriction fragment length polymorphism (RFLP) assays revealed that the CYP2D6 extensive metabolizer genotype (CYP2D6*1A) is over represented in bladder cancer patients compared to controls (79 versus 44%, respectively) and is significantly associated with increased risk for bladder cancer (odds ratio (OR) = 4.5, 95% confidence limit (CL) = 1.3-15.7, P = 0.006). Our results also indicate that individuals who have inherited this genotype are more likely to develop TCC (OR = 5.9, 95% CL = 1.4-27.9, P = 0.006) rather than SCC (OR = 3.1, 95% CL = 0.7-15.9; P = 0.09). When the relative risk associated with this genotype was estimated among subjects who were smokers or schistosoma infected, the same tendency towards the development of TCC was observed. These data suggest that the predisposing CYP2D6 gene may not only increase the risk for bladder cancer among Egyptians, but may also influence the clinicopathological tumor outcome. PMID:18372530

  15. Up-Regulation of CYP2C19 Expression by BuChang NaoXinTong via PXR Activation in HepG2 Cells

    PubMed Central

    Wu, Xiao-Ying; Wang, Huan; Qu, Qiang; Tan, Shen-Lan; Ruan, Jun-Shan; Qu, Jian; Chen, Hui

    2016-01-01

    Background Cytochrome P450 2C19 (CYP2C19) is an important drug-metabolizing enzyme (DME), which is responsible for the biotransformation of several kinds of drugs such as proton pump inhibitors, platelet aggregation inhibitors and antidepressants. Previous studies showed that Buchang NaoXinTong capsules (NXT) increased the CYP2C19 metabolic activity in vitro and enhanced the antiplatelet effect of clopidogrel in vivo. However, the underlying molecular mechanism remained unclear. In the present study, we examined whether Pregnane X receptor (PXR) plays a role in NXT-mediated regulation of CYP2C19 expression. Methods We applied luciferase assays, real-time quantitative PCR (qPCR), Western blotting and cell-based analysis of metabolic activity experiments to investigate the NXT regulatory effects on the CYP2C19 promoter activity, the mRNA/ protein expression and the metabolic activity. Results Our results demonstrated that NXT significantly increased the CYP2C19 promoter activity when co-transfected with PXR in HepG2 cells. Mutations in PXR responsive element abolished the NXT inductive effects on the CYP2C19 promoter transcription. Additionally, NXT incubation (150 and 250μg/mL) also markedly up-regulated endogenous CYP2C19 mRNA and protein levels in PXR-transfected HepG2 cells. Correspondingly, NXT leaded to a significant enhancement of the CYP2C19 catalytic activity in PXR-transfected HepG2 cells. Conclusion In summary, this is the first study to suggest that NXT could induce CYP2C19 expression via PXR activation. PMID:27467078

  16. The Effects of CYP2C19 genotype on the susceptibility for nephrosis in cardio-cerebral vascular disease treated by anticoagulation

    PubMed Central

    Chang, Kai; Jiang, Zhongyong; Liu, Chenxia; Ren, Junlong; Wang, Ting; Xiong, Jie

    2016-01-01

    Abstract In recent years, the genetic factor has become one of the important predisposing factors of nephropathy susceptibility. There is a high incidence of nephropathy in CCVd. The CYP2C19 enzyme metabolizes most the drugs, including proton pump inhibitors commonly used medicines to treat CCVd, CYP2C19 genetic polymorphisms is association with multi-pathogenesis factors of nephropathy. The purpose of the study is to reveal the association between CYP2C19 genotype and the susceptibility of nephropathy in the CCVd patients. The study is composed of 623 samples from CCVd treated by anticoagulation. The patients were studied, including CCVd with hyperuricemia, coronary heart disease, diabetes, and other complication. Biochemical tests and CYP2C19 variants measurements were performed by the gene chip method. The association among CYP2C19 variants, complications, and nephropathy was analyzed in the CCVd. There is no correlation between nephropathy and complications in CCVd. In hyperuricemia, coronary heart disease and diabetes groups, the differences of renal function tests were significant between CYP2C19 mutant (P < 0.05). The nephropathy risk of wild genotype is 3.288 times higher than of mutation genotype in hyperuricemic group, 1.928 times higher than mutation genotype in coronary heart disease group, and 5.248 times higher than CYP2C19 mutation genotype in the diabetic group. There was significant correlation between the CYP2C19 wild type and the nephropathy susceptibility in CCVd patients. The CYP2C19 gene plays a potential maker to evaluate nephropathy in CCVd patients. We deduced that identification of CYP2C19 gene type may benefit for reducing and avoiding nephropathy caused by abnormal metabolism function in CCVd patients. PMID:27661054

  17. The Effects of CYP2C19 genotype on the susceptibility for nephrosis in cardio-cerebral vascular disease treated by anticoagulation.

    PubMed

    Chang, Kai; Jiang, Zhongyong; Liu, Chenxia; Ren, Junlong; Wang, Ting; Xiong, Jie

    2016-09-01

    In recent years, the genetic factor has become one of the important predisposing factors of nephropathy susceptibility. There is a high incidence of nephropathy in CCVd. The CYP2C19 enzyme metabolizes most the drugs, including proton pump inhibitors commonly used medicines to treat CCVd, CYP2C19 genetic polymorphisms is association with multi-pathogenesis factors of nephropathy. The purpose of the study is to reveal the association between CYP2C19 genotype and the susceptibility of nephropathy in the CCVd patients. The study is composed of 623 samples from CCVd treated by anticoagulation. The patients were studied, including CCVd with hyperuricemia, coronary heart disease, diabetes, and other complication. Biochemical tests and CYP2C19 variants measurements were performed by the gene chip method. The association among CYP2C19 variants, complications, and nephropathy was analyzed in the CCVd. There is no correlation between nephropathy and complications in CCVd. In hyperuricemia, coronary heart disease and diabetes groups, the differences of renal function tests were significant between CYP2C19 mutant (P < 0.05). The nephropathy risk of wild genotype is 3.288 times higher than of mutation genotype in hyperuricemic group, 1.928 times higher than mutation genotype in coronary heart disease group, and 5.248 times higher than CYP2C19 mutation genotype in the diabetic group. There was significant correlation between the CYP2C19 wild type and the nephropathy susceptibility in CCVd patients. The CYP2C19 gene plays a potential maker to evaluate nephropathy in CCVd patients. We deduced that identification of CYP2C19 gene type may benefit for reducing and avoiding nephropathy caused by abnormal metabolism function in CCVd patients. PMID:27661054

  18. [Cytochrome P4502C9(CYP2C9) gene polymorphism and safety of therapy with warfarin].

    PubMed

    Mikheeva, Iu A; Kropacheva, E S; Ignat'ev, I V; Bulytova, Iu M; Ramenskaia, G V; Sychev, D A; Dobrovol'skiĭ, A B; Panchenko, E P

    2008-01-01

    Aim of the study was to investigate frequency and influence of alleles CYP2C9*2 and CYP2C9*3 on pharmacokinetics, pharmacodynamics and dosing regimen of warfarin and on development of hemorrhagic complications. We included 84 patients (mean age 62,8 +/- 10,5 years). Duration of follow-up varied between 1 month and 1 year. Carriage of allele variants was determined by polymerase chain reaction, measurement of plasma wafarin concentration was carried out with the help of high performance liquid chromatography. Wild type (CYP2C9*1/*1) was found in 68% of patients; overall frequency of 2C9*1/*1, *l/*3, *2/*2, *3/*3, *2/*3 genotypes was 32%. Average maintenance doses of warfarin for patients with allele variants CYP 2C9 *2 and 2C9 *3 were 3.6 and 3.1 mg/day, respectively, what was significantly lower than in wild type homozygotes (6.1 mg/day). Wild type homozygotes (1) had the highest warfarin clearance (3,51 ml/min). In carriers of 2C9 *2(2) and 2C9 *3(3) warfarin clearance was significantly lower (2.42 and 1.82 ml/min; p1 - 2 = 0,05; p1 - 3 = 0,0008). In carriers of allele variants CYP2C9*2, CYP2C9*3 values of international normalized ratio > 3,0 were met more often, especially in carriers of CYP2C9*3 (in 100% of cases) vs. 28% in wild type homozygotes (p=0,02). Carriers of CYP2C9*3 compared with wild type homozygotes had more hemorrhagic complications (67% and 16%, respectively, p=0,0008). Thus cytochrome P450 2C9 gene polymorphism influences frequency of development of hemorrhagic complications, metabolic clearance, and magnitude of warfarin maintenance dose. PMID:18429757

  19. The effect of ethinyloestradiol and levonorgestrel on the CYP2C19-mediated metabolism of omeprazole in healthy female subjects

    PubMed Central

    Palovaara, Sanna; Tybring, Gunnel; Laine, Kari

    2003-01-01

    Aims To study the effect of an oral contraceptive (OC) formulation containing ethinyloestradiol and levonorgestrel (LNG) (combination OC) or LNG alone on the CYP2C19-mediated hydroxylation of omeprazole in healthy females. Methods This was an open crossover study with three phases. In phase one, 10 healthy females received a single 40-mg dose of omeprazole. Thereafter the subjects received in a random order either 40 µg ethinyloestradiol and 75 µg LNG or 60 µg LNG alone once daily for 10 days. On day 10, 1 h after the last OC dose, subjects received a single 40-mg oral dose of omeprazole. The plasma concentrations of omeprazole, 5′-hydroxyomeprazole and omeprazole sulphone were determined for up to 8 h. Results The use of combination OC increased the area under the curve (AUC) of omeprazole by 38% [95% confidence interval (CI) − 3.8, 80; P = 0.040] and caused a 48% increase (95% CI 28, 68) in the AUC ratio of omeprazole/5-hydroxyomeprazole. LNG alone did not effect the 5′-hydroxylation of omeprazole. Neither of the OC preparations seemed to have an inhibitory effect on the formation of omeprazole sulphone by CYP3A4. Conclusions Oral contraceptives containing ethinyloestradiol but not those containing only LNG decrease CYP2C19 activity. PMID:12895199

  20. Comparative QSAR analyses of competitive CYP2C9 inhibitors using three-dimensional molecular descriptors.

    PubMed

    Lather, Viney; Fernandes, Miguel X

    2011-07-01

    One of the biggest challenges in QSAR studies using three-dimensional descriptors is to generate the bioactive conformation of the molecules. Comparative QSAR analyses have been performed on a dataset of 34 structurally diverse and competitive CYP2C9 inhibitors by generating their lowest energy conformers as well as additional multiple conformers for the calculation of molecular descriptors. Three-dimensional descriptors accounting for the spatial characteristics of the molecules calculated using E-Dragon were used as the independent variables. The robustness and the predictive performance of the developed models were verified using both the internal [leave-one-out (LOO)] and external statistical validation (test set of 12 inhibitors). The best models (MLR using GETAWAY descriptors and partial least squares using 3D-MoRSE) were obtained by using the multiple conformers for the calculation of descriptors and were selected based upon the higher external prediction ( values of 0.65 and 0.63, respectively) and lower root mean square error of prediction (0.48 and 0.48, respectively). The predictive ability of the best model, i.e., MLR using GETAWAY descriptors was additionally verified on an external test set of quinoline-4-carboxamide analogs and resulted in an value of 0.6. These simple and alignment-independent QSAR models offer the possibility to predict CYP2C9 inhibitory activity of chemically diverse ligands in the absence of X-ray crystallographic information of target protein structure and can provide useful insights about the ADMET properties of candidate molecules in the early phases of drug discovery.

  1. Evaluation of flurbiprofen urinary ratios as in vivo indices for CYP2C9 activity

    PubMed Central

    Zgheib, N K; Frye, R F; Tracy, T S; Romkes, M; Branch, R A

    2007-01-01

    Aims We investigated flurbiprofen pharmacokinetics in 12 volunteers to develop a phenotypic trait measure that correlates with the fractional clearance to 4′-hydroxyflurbiprofen. The effect of the CYP2C9 inhibitor fluconazole on flurbiprofen metabolism was also evaluated. Methods Flurbiprofen pharmacokinetics were evaluated before and after the first and seventh doses of fluconazole. The urinary recovery ratio was calculated as FLRR = 4′-OHF/ [4′-OHF + Ftot] and the urinary metabolic ratio was calculated as FLMR = 4′-OHF/Ftot, where 4′-OHF and Ftot represent total (conjugated and unconjugated) amounts recovered in urine. Results There was a statistically significant relationship between the 4′-OHF formation clearance (4OHCLf) and both the 8-h FLRR and the 8-h FLMR with and without administration of fluconazole. The flurbiprofen apparent oral clearance (CL/F) was decreased by 53% [90% confidence interval (CI) −58, −48] and 64% (90% CI −69, −59), respectively, after administration of one and seven doses of fluconazole when compared with administration of flurbiprofen alone; similarly, the 4OHCLf decreased by 69% (90% CI −74, −64) and 78% (90% CI −83, −73), the 8-h FLRR decreased by 35% (90% CI −41, −29) and 40% (90% CI −46, −35) and the 8-h FLMR decreased by 61% (90% CI −65, −58) and 67% (90% CI −70, −63). The magnitude of decrease in CL/F and 4OHCLf was greater after seven doses compared with after one dose of fluconazole (P < 0.005). Conclusions This study provides strong evidence that both the 8-h FLRR and the 8-h FLMR are suitable phenotypic indices for CYP2C9 activity. PMID:17054666

  2. The cytochrome P450 2D6*10 genetic polymorphism alters postoperative analgesia

    PubMed Central

    Wei, Xiao-Bin; Xiao, Xi; Han, Zhou-Xin; Lin, Dan-Qin; Yu, Ping

    2015-01-01

    The present study was aimed to investigate the effects of the cytochrome P450 (CYP) 2D6*10 genetic polymorphism on postoperative patient-controlled morphine usage. A total of 114 patients were selected, and 102 patients completed the study. Polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) was used to determine the CYP2D6*10 genotype, and patients were categorized into three groups according to CYP2D6 genotype: heterozygous (m/w), wild-type homozygous (w/w), and mutant homozygous (m/m). Total morphine usage and visual analogue score (VAS) were determined 72 hours after the operation and compared across the three genotype groups. Statistical methods used to analyze results were the χ2 test, analysis of variance, and multiple linear regression analysis; P<0.05 was considered to be statistically significant. The cumulative use of morphine in the m/w group was significantly higher than that in the m/m group between T0.5 and T4h (P<0.05). There were no significant differences in the loading dose of morphine or VAS among the different genotypes within 72 hours of operation. Patients carrying the CYP2D6*10 m/w genotype required higher doses of morphine at T0.5~T4h compared to the m/m group, and therefore received a higher cumulative dose of morphine post-operation. This phenomenon may be due to a decreased ability to synthesize endogenous opioid peptide. PMID:25932231

  3. Gene variants in CYP2C19 are associated with altered in vivo bupropion pharmacokinetics but not bupropion-assisted smoking cessation outcomes.

    PubMed

    Zhu, Andy Z X; Zhou, Qian; Cox, Lisa Sanderson; Ahluwalia, Jasjit S; Benowitz, Neal L; Tyndale, Rachel F

    2014-11-01

    Bupropion is used clinically to treat depression and to promote smoking cessation. It is metabolized by CYP2B6 to its active metabolite hydroxybupropion, yet alterations in CYP2B6 activity have little impact on bupropion plasma levels. Furthermore, less than 10% of a bupropion dose is excreted as urinary bupropion and its characterized metabolites hydroxybupropion, threohydrobupropion, and erythrohydrobupropion, suggesting that alternative metabolic pathways may exist. In vitro data suggested CYP2C19 could metabolize bupropion. The current study investigated the impact of functional CYP2C19 genetic variants on bupropion pharmacokinetics and treatment outcomes. In 42 healthy volunteers, CYP2C19*2 (a reduced activity allele) was associated with higher bupropion area under the plasma concentration-time curve (AUC), but similar hydroxybupropion AUC. The mean bupropion AUC was 771 versus 670 hours⋅ng/ml in individuals with and without CYP2C19*2, respectively (P = 0.017). CYP2C19*2 was also associated with higher threohydrobupropion and erythrohydrobupropion AUC (P < 0.005). Adjusting for CYP2B6 genotype did not alter these associations, and CYP2C19 variants did not alter the utility of the hydroxybupropion/bupropion ratio as a measure of CYP2B6 activity. Finally, in a clinical trial of 540 smokers, CYP2C19 genotype was not associated with smoking cessation outcomes, supporting the hypothesis that bupropion response is mediated by hydroxybupropion, which is not altered by CYP2C19. In conclusion, our study reports the first in vivo evidence that reduced CYP2C19 activity significantly increases the steady-state exposure to bupropion and its reductive metabolites threohydrobupropion and erythrohydrobupropion. These pharmacokinetic changes were not associated with differences in bupropion's ability to promote smoking cessation in smokers, but may influence the side effects and toxicity associated with bupropion.

  4. Clinical outcomes associated with proton pump inhibitor use among clopidogrel-treated patients within CYP2C19 genotype groups following acute myocardial infarction

    PubMed Central

    Depta, Jeremiah P.; Lenzini, Petra A.; Lanfear, David E.; Wang, Tracy Y.; Spertus, John A.; Bach, Richard G.; Cresci, Sharon

    2014-01-01

    We examined clinical outcomes with proton pump inhibitors (PPI) use within CYP2C19 genotype groups during clopidogrel treatment following acute myocardial infarction (AMI). 2062 patients were genotyped for CYP2C19*2 and *17 variants in TRIUMPH. 12 month clinical outcomes were analyzed among patients discharged on clopidogrel within CYP2C19*2 carrier, CYP2C19*17 carrier, and CYP2C19*1 homozygote genotype groups. PPI use was not associated with a difference in mortality. Among clopidogrel-treated Caucasians following AMI, PPI use was associated with a significantly higher rate of cardiac rehospitalization (HR 1.62, 95% CI 1.19-2.19; p = 0.002) compared with no PPI use. PPI users who were carriers of the CYP2C19*17 variant experienced significantly higher rates of cardiac rehospitalization (HR 2.05, 95% CI 1.26-3.33; p = 0.003), carriers of the CYP2C19*2 variant had a trend toward increased 1-year cardiac rehospitalization (HR 1.69, 95% CI 0.95-2.99; P=0.07) while no significant differences were observed among CYP2C19*1 homozygotes. These results indicate that the risks associated with PPI use among clopidogrel-treated Caucasian post-MI patients are impacted by CYP2C19 genotype, and suggest knowledge of genotype may be useful for personalizing PPI use among patients following AMI to reduce rehospitalization. PMID:25001880

  5. Comparison of Paeoniflorin and Albiflorin on Human CYP3A4 and CYP2D6

    PubMed Central

    Gao, Li-Na; Zhang, Ye; Cui, Yuan-Lu; Akinyi, Olunga Mary

    2015-01-01

    Peony (Paeonia lactiflora Pall-) is a plant medicine and a functional food ingredient with wide application for more than 2000 years. It can be coadministrated with many other drugs, composed of traditional Chinese medicine compound such as shaoyao-gancao decoction. In order to explore the efficacy and safety of peony, effects of paeoniflorin and albiflorin (the principal components of peony) on cytochrome P450 (CYP) 3A4 and CYP2D6 were analyzed in human hepatoma HepG2 cells and evaluated from the level of recombinant CYP enzymes in vitro. The findings indicated that albiflorin possessed stronger regulation on the mRNA expression of CYP3A4 and CYP2D6 than paeoniflorin. For the protein level of CYP3A4, albiflorin showed significant induction or inhibition with the concentration increasing from 10−7 M to 10−5 M, but no remarkable variation was observed in paeoniflorin-treated group. Enzyme activity assay implied that both paeoniflorin and albiflorin could regulate CYP3A4 and CYP2D6 with varying degrees. The results showed that albiflorin should be given more attention because it may play a vital role on the overall efficacy of peony. The whole behavior of both paeoniflorin and albiflorin should be focused on ensuring the rationality and effectiveness of clinical application. PMID:26089940

  6. Investigation of CYP2D6 Gene Polymorphisms in Turkish Population

    PubMed Central

    Taskin, Bayram; Percin, Ferda E.; Ergun, Mehmet Ali

    2016-01-01

    Pharmacogenetics is interested in the variable response to drugs depending on the genetic constitution of an individual. Depending on the genetic variation in individuals known as polymorphism; leads to differences in the types of proteins, enzymes or receptors that play a role in the elimination of drugs. Investigation of the correlation between the genotype with phenotype changes in drug metabolism is among the most important topics of today. CYP2D6 gene polymorphisms show clinical efficiency in the use of especially antidepressants, neuroleptics, antiarrhythmic, antihypertensive, beta blocker, and morphine derivatives. Poor metabolizers have been shown to demonstrate adverse drug reactions to these drugs. The plasma concentrations tend to increase inducing side effects after using a standard dose in poor metabolizers. The ratio of poor metabolizers in Caucasians is 5–10%, whereas 3.4–3.8% of the Turkish population. The allele frequencies of CYP2D6 *2, *3, *4 and *10 were found in 35%, 6%, 10% and 26% respectively in 200 healthy controls. The ratio of poor metabolizers in our population revealed as 1%. Genotyping of CYP2D6 is very important for determining a better genotype-phenotype relation.

  7. Practical interpretation of CYP2D6 haplotypes: Comparison and integration of automated and expert calling.

    PubMed

    Ruaño, Gualberto; Kocherla, Mohan; Graydon, James S; Holford, Theodore R; Makowski, Gregory S; Goethe, John W

    2016-05-01

    We describe a population genetic approach to compare samples interpreted with expert calling (EC) versus automated calling (AC) for CYP2D6 haplotyping. The analysis represents 4812 haplotype calls based on signal data generated by the Luminex xMap analyzers from 2406 patients referred to a high-complexity molecular diagnostics laboratory for CYP450 testing. DNA was extracted from buccal swabs. We compared the results of expert calls (EC) and automated calls (AC) with regard to haplotype number and frequency. The ratio of EC to AC was 1:3. Haplotype frequencies from EC and AC samples were convergent across haplotypes, and their distribution was not statistically different between the groups. Most duplications required EC, as only expansions with homozygous or hemizygous haplotypes could be automatedly called. High-complexity laboratories can offer equivalent interpretation to automated calling for non-expanded CYP2D6 loci, and superior interpretation for duplications. We have validated scientific expert calling specified by scoring rules as standard operating procedure integrated with an automated calling algorithm. The integration of EC with AC is a practical strategy for CYP2D6 clinical haplotyping.

  8. CYP2D6 variation, behaviour and psychopathology: implications for pharmacogenomics-guided clinical trials

    PubMed Central

    Peñas-LLedó, Eva M; LLerena, Adrián

    2014-01-01

    Individual and population differences in polymorphic cytochrome P450 enzyme function have been known for decades. The biological significance of these differences has now been deciphered with regard to drug metabolism, action and toxicity as well as disposition of endogenous substrates, including neuroactive compounds. While the cytochrome P450 enzymes occur abundantly in the liver, they are expressed in most tissues of the body, albeit in varying amounts, including the brain. The latter location of cytochrome P450s is highly pertinent for susceptibility to neuropsychiatric diseases, not to mention local drug metabolism at the site of psychotropic drug action in the brain. In the current era of personality medicine with companion theranostics (i.e. the fusion of therapeutics with diagnostics), this article underscores that such versatile biological roles of cytochrome P450s offer multiple points of entry for personalized medicine and rational therapeutics. We focus our discussion on CYP2D6, one of the most intensively researched drug and endogenous compound metabolism pathways, with a view to relevance for, and optimization of, pharmacogenomic-guided clinical trials. Working on the premise that CYP2D6 is related to human behaviour and certain personality traits such as serotonin and dopamine system function, we further suggest that the motivation of healthy volunteers to participate in clinical trials may in part be influenced by an under-or over-representation of certain CYP2D6 metabolic groups. PMID:24033670

  9. Comparison of Paeoniflorin and Albiflorin on Human CYP3A4 and CYP2D6.

    PubMed

    Gao, Li-Na; Zhang, Ye; Cui, Yuan-Lu; Akinyi, Olunga Mary

    2015-01-01

    Peony (Paeonia lactiflora Pall-) is a plant medicine and a functional food ingredient with wide application for more than 2000 years. It can be coadministrated with many other drugs, composed of traditional Chinese medicine compound such as shaoyao-gancao decoction. In order to explore the efficacy and safety of peony, effects of paeoniflorin and albiflorin (the principal components of peony) on cytochrome P450 (CYP) 3A4 and CYP2D6 were analyzed in human hepatoma HepG2 cells and evaluated from the level of recombinant CYP enzymes in vitro. The findings indicated that albiflorin possessed stronger regulation on the mRNA expression of CYP3A4 and CYP2D6 than paeoniflorin. For the protein level of CYP3A4, albiflorin showed significant induction or inhibition with the concentration increasing from 10(-7) M to 10(-5) M, but no remarkable variation was observed in paeoniflorin-treated group. Enzyme activity assay implied that both paeoniflorin and albiflorin could regulate CYP3A4 and CYP2D6 with varying degrees. The results showed that albiflorin should be given more attention because it may play a vital role on the overall efficacy of peony. The whole behavior of both paeoniflorin and albiflorin should be focused on ensuring the rationality and effectiveness of clinical application. PMID:26089940

  10. Influence of CYP2C9 and VKORC1 polymorphisms on warfarin and acenocoumarol in a sample of Lebanese people.

    PubMed

    Esmerian, Maria O; Mitri, Zahi; Habbal, Mohammad-Zuheir; Geryess, Eddy; Zaatari, Ghazi; Alam, Samir; Skouri, Hadi N; Mahfouz, Rami A; Taher, Ali; Zgheib, Nathalie K

    2011-10-01

    The authors assessed the impact of CYP2C9*2, CYP2C9*3, and/or VKORC1-1639G>A/1173C>T single-nucleotide polymorphisms on oral anticoagulants in a Lebanese population. This study recruited 231 Lebanese participants on long-term warfarin or acenocoumarol maintenance therapy with an international normalized ratio (INR) monitored at the American University of Beirut Medical Center. CYP2C9 and VKORC1 variant alleles were screened by real-time PCR. Plasma R- and S-warfarin and R- and S-acenocoumarol levels were assayed using high-performance liquid chromatography. The variant allele frequencies of CYP2C9*2, CYP2C9*3, and VKORC1 -1639G>A/1173C>T were 15.4%, 7.8%, and 52.4%, respectively. Fifty-five participants were excluded from analysis because of nontherapeutic INR values at recruitment, leaving 43 participants taking warfarin and 133 taking acenocoumarol. There was a significant decrease in the weekly maintenance dose of both drugs with CYP2C9 and VKORC1 variants when compared with wild-type patients. CYP2C9*2 had the least impact on the response to both drugs. The concentrations of R- and S-warfarin in plasma were significantly correlated with CYP2C9 genotypes. For acenocoumarol, time to reach target INR was more prolonged in patients carrying any CYP2C9 variant allele but failed to reach statistical significance because of low numbers of patients. There was no association between allelic variants and bleeding events. This is the first pharmacogenetic study of oral anticoagulants in Arabs. The authors showed that both CYP2C9 and VKORC1 polymorphisms are common in Lebanon and influence warfarin and acenocoumarol dose requirements, with the CYP2C9*2 polymorphism having less effect on acenocoumarol, the most commonly used oral anticoagulant in Lebanon. PMID:21148049

  11. Identification of CYP2C9 and VKORC1 polymorphisms in Iranian patients who are under warfarin therapy

    PubMed Central

    Poopak, Behzad; Rabieipoor, Saghar; Safari, Nazila; Naraghi, Emadedin; Sheikhsofla, Fatemeh; Khosravipoor, Gelareh

    2015-01-01

    Background: Although catalytic properties of different genetic polymorphisms of VKORC1 and CYP2C9 products have been identified, there is limited study available regarding warfarin dose requirement in Iranian patient population. This study investigates the impact of these polymorphisms on 115 patients, referred to Payvand Clinical and Specialty Laboratory for determining the appropriate dose of warfarin. Results of the study may be applicable to individuals who are under warfarin therapy to avoid warfarin resistance or intolerance. Subjects and Methods: PT-INR test was utilized as a screening method. Genotyping were performed for VKORC1 and CYP2C9 using PCR method. Statistical analyses including unpaired t-test or ANOVA and regression were done using SPSS. Results: VKORC1 GA was the most common genotype of VKORC1 allele among the study samples, with a rate of 57.4%. In CYP2C9 variant, 20% and 14.8% of subjects carried CYP2C9*1/*2 and CYP2C9*1/*3 genotyping, respectively. By contrast, the WT *1/*1 genotype was more abundant and dominant. The high frequency of VKORC1 (_1639) GA genotype (57.4%), was significant versus for the rest of the cohort (42.6%). In addition, a significant relationship was found between CYP2C9*1 and drug dose (P>0.021). Conclusion: In this study, samples were characterized by higher frequencies of CYP2C9*1 and VKORC1 G/A, determined as higher warfarin taking doses. The results showed a significant relationship of the VCORC1 and CYP2C9 polymorphisms with warfarin sensitivity and severe side effects. Estimating right doses of warfarin to prescribe can help to reduce the risk of over- or under-anticoagulation and subsequently, the risk of thromboembolism or bleeding. PMID:26865929

  12. Effects of pomegranate juice on human cytochrome P450 2C9 and tolbutamide pharmacokinetics in rats.

    PubMed

    Nagata, Masashi; Hidaka, Muneaki; Sekiya, Hiroshi; Kawano, Yohei; Yamasaki, Keishi; Okumura, Manabu; Arimori, Kazuhiko

    2007-02-01

    In this study, we investigated whether pomegranate juice could inhibit CYP2C9 activity. The ability of pomegranate juice to inhibit the diclofenac 4'-hydroxylase activity of human CYP2C9 was examined using human liver microsomes. Pomegranate juice was shown to be a potent inhibitor of human CYP2C9. The addition of 25 microl (5% v/v) of pomegranate juice resulted in almost complete inhibition of human CYP2C9 activity. In addition, we investigated the effect of pomegranate juice on the pharmacokinetics of tolbutamide (substrate for CYP2C9) in rats. Relative to the control group, the area under the concentration-time curve was approximately 1.2-fold greater when pomegranate juice (3 ml) was injected p.o. 1 h before the p.o. administration of the tolbutamide (20 mg/kg). The elimination half-life of tolbutamide was not altered by pomegranate juice administration. These results suggest pomegranate juice ingestion inhibits the intestinal metabolism of tolbutamide without inhibiting the hepatic metabolism in rats. Thus, we discovered that pomegranate juice inhibited human CYP2C9 activity and furthermore increased tolbutamide bioavailability in rats.

  13. In Silico Investigation of Cytochrome P450 2C9 in relation to Aging Using Traditional Chinese Medicine

    PubMed Central

    Hung, Tzu-Chieh; Kuo, Chia-Chen; Chen, Calvin Yu-Chian

    2014-01-01

    Cytochrome P450 2C9 (CYP2C9) metabolizes dehydroepiandrosterone-sulfate (DHEA-S), but in elderly people the amount of DHEA-S remaining after CYP2C9 metabolization may be insufficient for optimal health. A prediction model, molecular docking, and molecular dynamics were used to screen the Traditional Chinese Medicine (TCM) database to determine molecular compounds that may inhibit CYP2C9. The candidate compounds apocynoside(I), 4-methoxymagndialdehyde, and prunasin have higher Dock Scores, and prediction bioactivity than warfarin (the control drug). The interaction between 4-methoxymagndialdehyde and CYP2C9 is more intense than with other TCM compounds, but the simulation is longer. In these compounds, apocynoside(I) and prunasin have a greater number of pathways for their flexible structure, but these structures create weak interactions. These candidate compounds, which are known to have antioxidation and hypolipidemic functions that have an indirect effect on the aging process, can be extracted from traditional Chinese medicines. Thus, these candidate compounds may become CYP2C9 inhibitors and play an important role in providing optimal health in the elderly. PMID:24899908

  14. Long-Read Single Molecule Real-Time Full Gene Sequencing of Cytochrome P450-2D6.

    PubMed

    Qiao, Wanqiong; Yang, Yao; Sebra, Robert; Mendiratta, Geetu; Gaedigk, Andrea; Desnick, Robert J; Scott, Stuart A

    2016-03-01

    The cytochrome P450-2D6 (CYP2D6) enzyme metabolizes ∼25% of common medications, yet homologous pseudogenes and copy number variants (CNVs) make interrogating the polymorphic CYP2D6 gene with short-read sequencing challenging. Therefore, we developed a novel long-read, full gene CYP2D6 single molecule real-time (SMRT) sequencing method using the Pacific Biosciences platform. Long-range PCR and CYP2D6 SMRT sequencing of 10 previously genotyped controls identified expected star (*) alleles, but also enabled suballele resolution, diplotype refinement, and discovery of novel alleles. Coupled with an optimized variant-calling pipeline, CYP2D6 SMRT sequencing was highly reproducible as triplicate intra- and inter-run nonreference genotype results were completely concordant. Importantly, targeted SMRT sequencing of upstream and downstream CYP2D6 gene copies characterized the duplicated allele in 15 control samples with CYP2D6 CNVs. The utility of CYP2D6 SMRT sequencing was further underscored by identifying the diplotypes of 14 samples with discordant or unclear CYP2D6 configurations from previous targeted genotyping, which again included suballele resolution, duplicated allele characterization, and discovery of a novel allele and tandem arrangement. Taken together, long-read CYP2D6 SMRT sequencing is an innovative, reproducible, and validated method for full-gene characterization, duplication allele-specific analysis, and novel allele discovery, which will likely improve CYP2D6 metabolizer phenotype prediction for both research and clinical testing applications.

  15. QM/MM modeling of benzene hydroxylation in human cytochrome P450 2C9.

    PubMed

    Bathelt, Christine M; Mulholland, Adrian J; Harvey, Jeremy N

    2008-12-18

    The mechanism of benzene hydroxylation was investigated in the realistic enzyme environment of the human CYP 2C9 by using quantum mechanical/molecular mechanical (QM/MM) calculations of the whole reaction profile using the B3LYP method to describe the QM region. The calculated QM/MM barriers for addition of the active species Compound I to benzene are consistent with experimental rate constants for benzene metabolism in CYP 2E1. In contrast to gas-phase model calculations, our results suggest that competing side-on and face-on geometries of arene addition may both occur in the case of aromatic ring oxidation in cytochrome P450s. QM/MM profiles for three different rearrangement pathways of the initially formed sigma-adduct, leading to formation of epoxide, ketone, and an N-protonated porphyrin species, were calculated. Our results suggest that epoxide and ketone products form with comparable ease in the face-on pathway, whereas epoxide formation is preferred in the side-on pathway. Additionally, rearrangement to the N-protonated porphyrin species was found to be competitive with side-on epoxide formation. This suggests that overall, the competition between formation of epoxide and phenol final products in P450 oxidation of aromatic substrates is quite finely balanced. PMID:18754597

  16. Multiple, Ligand-Dependent Routes from the Active Site of Cytochrome P450 2C9

    SciTech Connect

    Cojocaru, Vlad; Winn, Peter J.; Wade, Rebecca C.

    2012-02-13

    The active site of liver-specific, drug-metabolizing cytochrome P450 (CYP) monooxygenases is deeply buried in the protein and is connected to the protein surface through multiple tunnels, many of which were found open in different CYP crystal structures. It has been shown that different tunnels could serve as ligand passage routes in different CYPs. However, it is not understood whether one CYP uses multiple routes for substrate access and product release and whether these routes depend on ligand properties. From 300 ns of molecular dynamics simulations of CYP2C9, the second most abundant CYP in the human liver we found four main ligand exit routes, the occurrence of each depending on the ligand type and the conformation of the F-G loop, which is likely to be affected by the CYP-membrane interaction. A non-helical F-G loop favored exit towards the putative membrane-embedded region. Important protein features that direct ligand exit include aromatic residues that divide the active site and whose motions control access to two pathways. The ligands interacted with positively charged residues on the protein surface through hydrogen bonds that appear to select for acidic substrates. The observation of multiple, ligand-dependent routes in a CYP aids understanding of how CYP mutations affect drug metabolism and provides new possibilities for CYP inhibition.

  17. Studies of novel deuterides RMn2D6 (R — rare earth) compressed in DAC up to 30 GPa

    NASA Astrophysics Data System (ADS)

    Filipek, S. M.; Sugiura, H.; Paul-Boncour, V.; Wierzbicki, R.; Liu, R. S.; Bagkar, N.

    2008-07-01

    The exposure of RMn2 (C15 or C14 cubic Laves phase, where R = Y; Dy; Ho or Er) to high deuterium pressure leads to formation of novel, unique YMn2D6, DyMn2D6, HoMn2D6 and ErMn2D6 deuterides with cubic Fm-3m symmetry. In spite of different structures and molecular volumes of parent RMn2 compounds, the molar volumes of RMn2D6 deuterides are almost identical. In this paper, we present results of studies on RMn2Dx (where R = Y, Dy, Ho and Er) submitted to compression up to 30 GPa in diamond anvil cell (DAC) combined with energy dispersive X-ray diffraction. The EOS (equation of state) parameters of the above four RMn2D6 samples and YMn2Dx, with x <= 4 are compared. The EOS parameters of YMn2D6 are very similar to those of other RMn2D6 but very different than those of interstitial deuterides YMn2Dx (x <= 4). The phase transition or segregation was not detected in RMn2D6 up to 30 GPa.

  18. Methylation of the Constitutive Androstane Receptor Is Involved in the Suppression of CYP2C19 in Hepatitis B Virus-Associated Hepatocellular Carcinoma.

    PubMed

    Tang, Xiaojing; Ge, Lele; Chen, Zhongjian; Kong, Sisi; Liu, Wenhui; Xu, Yingchun; Zeng, Su; Chen, Shuqing

    2016-10-01

    Hepatocellular carcinoma (HCC), one of the most dangerous malignancies with an increasing incidence and a high mortality rate, represents a major international health problem. HCC progression is known to involve genome-wide alteration of epigenetic modifications, leading to aberrant gene expression patterns. The activity of CYP2C19, an important member of the cytochrome P450 superfamily, was reported to be compromised in HCC, but the underlying mechanism remains unclear. To understand whether epigenetic modification in HCC is associated with a change in CYP2C19 activity, we evaluated the expression levels of CYP2C19 and its transcription factors by quantitative real-time polymerase chain reaction using mRNA extracted from both primary hepatocytes and paired tumor versus nontumor liver tissues of patients infected with hepatitis B virus (HBV). DNA methylation was examined by bisulfite sequencing and methylation-specific polymerase chain reaction. Our results indicated that CYP2C19 could be regulated by e-box methylation of the constitutive androstane receptor (CAR). Decreased CYP2C19 expression in tumorous tissues of HBV-infected patients with HCC was highly correlated with suppressed expression and promoter hypermethylation of CAR. Our study demonstrates that aberrant CAR methylation is involved in CYP2C19 regulation in HBV-related HCC and may play a role in liver tumorigenesis.

  19. Implementation of Cell Samples as Controls in National Proficiency Testing for Clopidogrel Therapy-Related CYP2C19 Genotyping in China: A Novel Approach

    PubMed Central

    Zhang, Kuo; Wang, Lunan; Zhang, Rui; Xie, Jiehong; Li, Jinming

    2015-01-01

    Laboratories are increasingly requested to perform CYP2C19 genetic testing when managing clopidogrel therapy, especially in patients with acute coronary syndrome undergoing percutaneous coronary intervention. To ensure high quality molecular testing and ascertain that the referring clinician has the correct information for CYP2C19 genotype–directed antiplatelet therapy, a proficiency testing scheme was set up to evaluate the laboratory performance for the entire testing process. Proficiency panels of 10 cell samples encompassing the common CYP2C19 genetic polymorphisms were distributed to 62 participating laboratories for routine molecular testing and the responses were analyzed for accuracy of genotyping and the reporting of results. Data including the number of samples tested, the accreditation/certification status, and test methodology of each individual laboratory were also reviewed. Fifty-seven of the 62 participants correctly identified the CYP2C19 variants in all samples. There were six genotyping errors, with a corresponding analytical sensitivity of 98.5% (333/338 challenges; 95% confidence interval: 96.5–99.5%) and an analytic specificity of 99.6% (281/282; 95% confidence interval: 98.0–99.9%). Reports of the CYP2C19 genotyping results often lacked essential information. In conclusion, clinical laboratories demonstrated good analytical sensitivity and specificity; however, the pharmacogenetic testing community requires additional education regarding the correct reporting of CYP2C19 genetic test results. PMID:26218263

  20. Two flavonolignans from milk thistle (Silybum marianum) inhibit CYP2C9-mediated warfarin metabolism at clinically achievable concentrations.

    PubMed

    Brantley, Scott J; Oberlies, Nicholas H; Kroll, David J; Paine, Mary F

    2010-03-01

    Milk thistle (Silybum marianum) is a popular herbal product used for hepatoprotection and chemoprevention. Two commercially available formulations are the crude extract, silymarin, and the semipurified product, silibinin. Silymarin consists of at least seven flavonolignans, of which the most prevalent are the diastereoisomers silybin A and silybin B; silibinin consists only of silybin A and silybin B. Based on a recent clinical study showing an interaction between a silymarin product and the CYP2C9 substrate losartan, the CYP2C9 inhibition properties of silybin A and silybin B and corresponding regioisomers, isosilybin A and isosilybin B, were evaluated using human liver microsomes (HLMs), recombinant CYP2C9 (rCYP2C9) enzymes, and the clinically relevant probe, (S)-warfarin. Silybin B was the most potent inhibitor in HLMs, followed by silybin A, isosilybin B, and isosilybin A (IC(50) of 8.2, 18, 74, and >100 microM, respectively). Next, silybin A and silybin B were selected for further characterization. As with HLMs, silybin B was more potent than silybin A toward rCYP2C9 1 (6.7 versus 12 microM), rCYP2C9 2 (9.3 versus 19 microM), and rCYP2C9 3 (2.4 versus 9.3 microM). Using a matrix of five substrate (1-15 microM) and six inhibitor (1-80 microM) concentrations and HLMs, both diastereoisomers inhibited (S)-warfarin 7-hydroxylation in a manner described best by a mixed-type inhibition model (K(i) values of 4.8 and 10 microM for silybin B and silybin A, respectively). These observations, combined with the high systemic silibinin concentrations (>5-75 microM) achieved in a phase I study involving prostate cancer patients, prompt clinical evaluation of a potential warfarin-milk thistle interaction.

  1. Two Flavonolignans from Milk Thistle (Silybum marianum) Inhibit CYP2C9-Mediated Warfarin Metabolism at Clinically Achievable Concentrations

    PubMed Central

    Brantley, Scott J.; Oberlies, Nicholas H.; Kroll, David J.

    2010-01-01

    Milk thistle (Silybum marianum) is a popular herbal product used for hepatoprotection and chemoprevention. Two commercially available formulations are the crude extract, silymarin, and the semipurified product, silibinin. Silymarin consists of at least seven flavonolignans, of which the most prevalent are the diastereoisomers silybin A and silybin B; silibinin consists only of silybin A and silybin B. Based on a recent clinical study showing an interaction between a silymarin product and the CYP2C9 substrate losartan, the CYP2C9 inhibition properties of silybin A and silybin B and corresponding regioisomers, isosilybin A and isosilybin B, were evaluated using human liver microsomes (HLMs), recombinant CYP2C9 (rCYP2C9) enzymes, and the clinically relevant probe, (S)-warfarin. Silybin B was the most potent inhibitor in HLMs, followed by silybin A, isosilybin B, and isosilybin A (IC50 of 8.2, 18, 74, and >100 μM, respectively). Next, silybin A and silybin B were selected for further characterization. As with HLMs, silybin B was more potent than silybin A toward rCYP2C9*1 (6.7 versus 12 μM), rCYP2C9*2 (9.3 versus 19 μM), and rCYP2C9*3 (2.4 versus 9.3 μM). Using a matrix of five substrate (1–15 μM) and six inhibitor (1–80 μM) concentrations and HLMs, both diastereoisomers inhibited (S)-warfarin 7-hydroxylation in a manner described best by a mixed-type inhibition model (Ki values of 4.8 and 10 μM for silybin B and silybin A, respectively). These observations, combined with the high systemic silibinin concentrations (>5–75 μM) achieved in a phase I study involving prostate cancer patients, prompt clinical evaluation of a potential warfarin-milk thistle interaction. PMID:19934397

  2. PREVALENCE OF COMBINATORIAL CYP2C9 AND VKORC1 GENOTYPES IN PUERTO RICANS: IMPLICATIONS FOR WARFARIN MANAGEMENT IN HISPANICS

    PubMed Central

    Duconge, Jorge; Cadilla, Carmen L.; Windemuth, Andreas; Kocherla, Mohan; Gorowski, Krystyna; Seip, Richard L.; Bogaard, Kali; Renta, Jessica Y.; Piovanetti, Paola; D’Agostino, Darrin; Santiago-Borrero, Pedro J.; Ruaño, Gualberto

    2010-01-01

    Polymorphisms in the cytochrome P450 2C9 (CYP2C9) and vitamin K epoxide reductase complex subunit 1 (VKORC1) genes significantly alter the effective warfarin dose. We determined the frequencies of alleles, single carriers, and double carriers of single nucleotide polymorphisms (SNPs) in the CYP2C9 and VKORC1 genes in a Puerto Rican cohort and gauged the impact of these polymorphisms on warfarin dosage using a published algorithm. A total of 92 DNA samples were genotyped using Luminex® x-MAP technology. The polymorphism frequencies were 6.52%, 5.43% and 28.8% for CYP2C9 *2, *3 and VKORC1-1639 G>A polymorphisms, respectively. The prevalence of combinatorial genotypes was 16% for carriers of both the CYP2C9 and VKORC1 polymorphisms, 9% for carriers of CYP2C9 polymorphisms, 35% for carriers of the VKORC1 polymorphism, and the remaining 40% were non-carriers for either gene. Based on a published warfarin dosing algorithm, single, double and triple carriers of functionally deficient polymorphisms predict reductions of 1.0–1.6, 2.0–2.9, and 2.9–3.7 mg/day, respectively, in warfarin dose. Overall, 60% of the population carried at least a single polymorphism predicting deficient warfarin metabolism or responsiveness and 13% were double carriers with polymorphisms in both genes studied. Combinatorial genotyping of CYP2C9 and VKORC1 can allow for individualized dosing of warfarin among patients with gene polymorphisms, potentially reducing the risk of stroke or bleeding. PMID:20073138

  3. Prevalence of combinatorial CYP2C9 and VKORC1 genotypes in Puerto Ricans: implications for warfarin management in Hispanics.

    PubMed

    Duconge, Jorge; Cadilla, Carmen L; Windemuth, Andreas; Kocherla, Mohan; Gorowski, Krystyna; Seip, Richard L; Bogaard, Kali; Renta, Jessica Y; Piovanetti, Paola; D'Agostino, Darrin; Santiago-Borrero, Pedro J; Ruaño, Gualberto

    2009-01-01

    Polymorphisms in the cytochrome P450 2C9 (CYP2C9) and vitamin K epoxide reductase complex subunit 1 (VKORC1) genes significantly alter the effective warfarin dose. We determined the frequencies of alleles, single carriers, and double carriers of single nucleotide polymorphisms (SNPs) in the CYP2C9 and VKORC1 genes in a Puerto Rican cohort and gauged the impact of these polymorphisms on warfarin dosage using a published algorithm. A total of 92 DNA samples were genotyped using Luminex x-MAP technology. The polymorphism frequencies were 6.52%, 5.43% and 28.8% for CYP2C9 *2, *3 and VKORC1-1639 C>A polymorphisms, respectively. The prevalence of combinatorial genotypes was 16% for carriers of both the CYP2C9 and VKORC1 polymorphisms, 9% for carriers of CYP2C9 polymorphisms, 35% for carriers of the VKORC1 polymorphism, and the remaining 40% were non-carriers for either gene. Based on a published warfarin dosing algorithm, single, double and triple carriers of functionally deficient polymorphisms predict reductions of 1.0-1.6, 2.0-2.9, and 2.9-3.7 mg/day, respectively, in warfarin dose. Overall, 60% of the population carried at least a single polymorphism predicting deficient warfarin metabolism or responsiveness and 13% were double carriers with polymorphisms in both genes studied. Combinatorial genotyping of CYP2C9 and VKORC1 can allow for individualized dosing of warfarin among patients with gene polymorphisms, potentially reducing the risk of stroke or bleeding.

  4. CYP2C19 polymorphisms in the Thai population and the clinical response to clopidogrel in patients with atherothrombotic-risk factors

    PubMed Central

    Sukasem, Chonlaphat; Tunthong, Ramaimon; Chamnanphon, Montri; Santon, Siwalee; Jantararoungtong, Thawinee; Koomdee, Napatrupron; Prommas, Santirhat; Puangpetch, Apichaya; Vathesatogkit, Prin

    2013-01-01

    Genetic variation in the cytochrome P450 2C19 (CYP2C19) gene has been documented gradually as the determinant conversion and variability in the antiplatelet effect of clopidogrel. The aims of this study were to determine the prevalence of clinically relevant allele variants (CYP2C19*2, CYP2C19*3, and CYP2C19*17) in a Thai study population, and finally determine whether the allele distributes and predicts metabolic phenotypes in clopidogrel treated patients. A total of 1,051 Thai patients participated in this study. Genotypes for CYP2C19 polymorphisms were detected by the microarray-based technique. Furthermore, results of genotyping and platelet aggregation in 96 cardiovascular disease patients on 75 mg clopidogrel maintenance daily dose therapy also were analyzed. Among 1,051 samples, the allele frequencies of CYP2C19 *1/*1, *1/*2, *1/*3, *2/*2, *2/*3, and *1/*17 were found in 428 (40.72%), 369 (35.10%), 72 (6.85%), 77 (7.32%), 59 (5.61%), and 45 (4.30%) of the patients, respectively. Homozygous CYP2C19 *3/*3 was found in one patient (0.10%). Therefore, 40.72% of the patients were predicted as extensive metabolizers, 41.95% as intermediate metabolizers, 13.03% as poor metabolizers, and 4.30% as ultra-rapid metabolizers. Among 96 patients, the frequency of poor metabolizers was significantly higher in the clopidogrel non-responder group than in the responder group (36.0% and 15.5%, respectively, P = 0.03). CYP2C19*1/*17 was observed in responders (n = 2; 2.8%). As a result, CYP2C19 variants were associated with clopidogrel non-responders. However, there is a need for further elucidation of the clinical importance and use of this finding to make firm and cost-effective recommendations for drug treatment in the future. PMID:24019752

  5. Tamoxifen metabolite concentrations, CYP2D6 genotype, and breast cancer outcomes.

    PubMed

    Madlensky, L; Natarajan, L; Tchu, S; Pu, M; Mortimer, J; Flatt, S W; Nikoloff, D M; Hillman, G; Fontecha, M R; Lawrence, H J; Parker, B A; Wu, A H B; Pierce, J P

    2011-05-01

    We explored whether breast cancer outcomes are associated with endoxifen and other metabolites of tamoxifen and examined potential correlates of endoxifen concentration levels in serum including cytochrome P450 2D6 (CYP2D6) metabolizer phenotype and body mass index (BMI). Concentration levels of tamoxifen, endoxifen, 4-hydroxytamoxifen (4OH-tamoxifen), and N-desmethyltamoxifen (ND-tamoxifen) were measured from samples taken from 1,370 patients with estrogen receptor (ER)-positive breast cancer who were participating in the Women's Healthy Eating and Living (WHEL) Study. We tested these concentration levels for possible associations with breast cancer outcomes and found that breast cancer outcomes were not associated with the concentration levels of tamoxifen, 4-hydroxytamoxifen, and ND-tamoxifen. For endoxifen, a threshold was identified, with women in the upper four quintiles of endoxifen concentration appearing to have a 26% lower recurrence rate than women in the bottom quintile (hazard ratio (HR) = 0.74; 95% confidence interval (CI), (0.55-1.00)). The predictors of this higher-risk bottom quintile were poor/intermediate metabolizer genotype, higher BMI, and lower tamoxifen concentrations as compared with the mean for the cohort as a whole. This study suggests that there is a minimal concentration threshold above which endoxifen is effective against the recurrence of breast cancer and that ~80% of tamoxifen takers attain this threshold. PMID:21430657

  6. CYP2D6 and CYP2A6 biotransform dietary tyrosol into hydroxytyrosol.

    PubMed

    Rodríguez-Morató, Jose; Robledo, Patricia; Tanner, Julie-Anne; Boronat, Anna; Pérez-Mañá, Clara; Oliver Chen, C-Y; Tyndale, Rachel F; de la Torre, Rafael

    2017-02-15

    The dietary phenol tyrosol has been reported to be endogenously transformed into hydroxytyrosol, a potent antioxidant with multiple health benefits. In this work, we evaluated whether tyrosine hydroxylase (TH) and cytochrome P450s (CYPs) catalyzed this process. To assess TH involvement, Wistar rats were treated with α-methyl-L-tyrosine and tyrosol. Tyrosol was converted into hydroxytyrosol whilst α-methyl-L-tyrosine did not inhibit the biotransformation. The role of CYP was assessed in human liver microsomes (HLM) and tyrosol-to-hydroxytyrosol conversion was observed. Screening with selective enzymatic CYP inhibitors identified CYP2A6 as the major isoform involved in this process. Studies with baculosomes further demonstrated that CYP2D6 and CYP3A4 could transform tyrosol into hydroxytyrosol. Experiments using human genotyped livers showed an interindividual variability in hydroxytyrosol formation and supported findings that CYP2D6 and CYP2A6 mediated this reaction. The dietary health benefits of tyrosol-containing foods remain to be evaluated in light of CYP pharmacogenetics. PMID:27664690

  7. Systematic characterization and comparison of the CYP2C9 variability of the Orang Asli in Malaysia with 12 populations.

    PubMed

    Teh, Lay Kek; Subramaniam, Vinothini; Tuan Abdu Aziz, Tuan Azlin; Lee, Lian Shien; Ismail, Mohamed Izwan; Yu, Choo Yee; Ang, Geik Yong; James Johari, Richard; Ismet, Rose Iszati; Sahak, Noor Saadah; Ahmad, Aminuddin; Rahman, Thuhairah Abdul; Nor Ghazali, Fadzilah Mohd; Shaari, SyahrulAzlin; Omar, Mustaffa; Ismail, Adzrool Idzwan; Md Isa, Kamarudzaman; Salleh, Hood; Salleh, Mohd Zaki

    2016-08-01

    We conducted a systematic characterization of CYP2C9 variants in 61 Orang Asli and 96 Singaporean Malays using the whole genome sequences data and compared the variants with the other 11 HapMap populations. The frequency of rs1057910 (CYP2C9*3) is the highest in the Orang Asli compared to other populations. Three alleles with clinical implication were detected in the Orang Asli while 2 were found in the Singaporean Malays. Large numbers of the Orang Asli are predicted to have reduced metabolic capacity and therefore they would require a lower dose of drugs which are metabolized by CYP2C9. They are also at increased risks of adverse effects and therapeutic failures. A large number of CYP2C9 variants in the Orang Asli were not in the Hardy Weinberg Equilibrium which could be due to small sample size or mutations that disrupt the equilibrium of allele frequencies. In conclusion, different polymorphism patterns, allele frequencies, genotype frequencies and LD blocks are observed between the Orang Asli, the Singaporean Malays and the other populations. The study provided new information on the genetic polymorphism of CYP2C9 which is important for the implementation of precision medicine for the Orang Asli. PMID:27325019

  8. Frequencies of poor metabolizers of cytochrome P450 2C19 in esophagus cancer, stomach cancer, lung cancer and bladder cancer in Chinese population

    PubMed Central

    Shi, Wei-Xing; Chen, Shu-Qing

    2004-01-01

    AIM: To investigate the association between cytochrome P450 2C19 (CYP2C19) gene polymorphism and cancer susceptibility by genotyping of CYP2C19 poor metabolizers (PMs) in cancer patients. METHODS: One hundred and thirty-five cases of esophagus cancer, 148 cases of stomach cancer, 212 cases of lung cancer, 112 cases of bladder cancer and 372 controls were genotyped by allele specific amplification-polymerase chain reaction (ASA-PCR) for CYP2C19 PMs. The frequencies of PMs in cancer groups and control group were compared. RESULTS: The frequencies of PMs of CYP2C19 were 34.1% (46/135) in the group of esophagus cancer patients, 31.8% (47/148) in the stomach cancer patients, 34.4% (73/212) in the group of lung cancer patients, only 4.5% (5/112) in the bladder cancer patients and 14.0% (52/372) in control group. There were statistical differences between the cancer groups and control group (esophagus cancer, χ2 = 25.65, P < 0.005, OR = 3.18, 95%CI = 2.005-5.042; stomach cancer, χ2 = 21.70, P < 0.005, OR = 2.86, 95%CI = 1.820-4.501; lung cancer, χ2 = 33.58, P < 0.005, OR = 3.23, 95%CI = 1.503-6.906; bladder cancer, χ2 = 7.50, P < 0.01, OR = 0.288, 95%CI = 0.112-0.740). CONCLUSION: CYP2C19 PMs have a high incidence of esophagus cancer, stomach cancer and lung cancer, conversely they have a low incidence of bladder cancer. It suggests that CYP2C19 may participate in the activation of procarcinogen of esophagus cancer, stomach cancer and lung cancer, but may involve in the detoxification of carcinogens of bladder cancer. PMID:15222046

  9. Different effects of proton pump inhibitors and famotidine on the clopidogrel metabolic activation by recombinant CYP2B6, CYP2C19 and CYP3A4.

    PubMed

    Ohbuchi, Masato; Noguchi, Kiyoshi; Kawamura, Akio; Usui, Takashi

    2012-07-01

    Inhibitory potential of proton pump inhibitors (PPIs) and famotidine, an H(2) receptor antagonist, on the metabolic activation of clopidogrel was evaluated using recombinant CYP2B6, CYP2C19 and CYP3A4. Formation of the active metabolite from an intermediate metabolite, 2-oxo-clopidogrel, was investigated by liquid chromatography-tandem mass spectrometry and three peaks corresponding to the pharmacologically active metabolite and its stereoisomers were detected. Omeprazole potently inhibited clopidogrel activation by CYP2C19 with an IC(50) of 12.8 μmol/L and more weakly inhibited that by CYP2B6 and CYP3A4. IC(50) of omeprazole for CYP2C19 and CYP3A4 was decreased about two- and three-fold, respectively, by 30-min preincubation with NADPH. Lansoprazole, esomeprazole, pantoprazole, rabeprazole and rabeprazole thioether, a major metabolite, also inhibited metabolic activation by CYP2C19, with an IC(50) of 4.3, 8.9, 48.3, 36.2 and 30.5 μmol/L, respectively. In contrast, famotidine showed no more than 20% inhibition of clopidogrel activation by CYP2B6, CYP2C19 and CYP3A4 at up to 100 μmol/L and had no time-dependent CYP2C19 and CYP3A4 inhibition. These results provide direct evidence that PPIs inhibit clopidogrel metabolic activation and suggest that CYP2C19 inhibition is the main cause of drug-drug interaction between clopidogrel and omeprazole. Famotidine is considered as a safe anti-acid agent for patients taking clopidogrel. PMID:22313038

  10. National Prociency Testing Result of CYP2D6*10 Genotyping for Adjuvant Tamoxifen Therapy in China.

    PubMed

    Lin, Guigao; Zhang, Kuo; Yi, Lang; Han, Yanxi; Xie, Jiehong; Li, Jinming

    2016-01-01

    Tamoxifen has been successfully used for treating breast cancer and preventing cancer recurrence. Cytochrome P450 2D6 (CYP2D6) plays a key role in the process of metabolizing tamoxifen to its active moiety, endoxifen. Patients with variants of the CYP2D6 gene may not receive the full benefit of tamoxifen treatment. The CYP2D6*10 variant (the most common variant in Asians) was analyzed to optimize the prescription of tamoxifen in China. To ensure referring clinicians have accurate information for genotype-guided tamoxifen treatment, the Chinese National Center for Clinical Laboratories (NCCL) organized a national proficiency testing (PT) to evaluate the performance of laboratories providing CYP2D6*10 genotyping. Ten genomic DNA samples with CYP2D6 wild-type or CYP2D6*10 variants were validated by PCR-sequencing and sent to 28 participant laboratories. The genotyping results and pharmacogenomic test reports were submitted and evaluated by NCCL experts. Additional information regarding the number of samples tested, the accreditation/certification status, and detecting technology was also requested. Thirty-one data sets were received, with a corresponding analytical sensitivity of 98.2% (548/558 challenges; 95% confidence interval: 96.7-99.1%) and an analytic specificity of 96.5% (675/682; 95% confidence interval: 97.9-99.5%). Overall, 25/28 participants correctly identified CYP2D6*10 status in 10 samples; however, two laboratories made serious genotyping errors. Most of the essential information was included in the 20 submitted CYP2D6*10 test reports. The majority of Chinese laboratories are reliable for detecting the CYP2D6*10 variant; however, several issues revealed in this study underline the importance of PT schemes in continued external assessment and provision of guidelines. PMID:27603206

  11. National Prociency Testing Result of CYP2D6*10 Genotyping for Adjuvant Tamoxifen Therapy in China.

    PubMed

    Lin, Guigao; Zhang, Kuo; Yi, Lang; Han, Yanxi; Xie, Jiehong; Li, Jinming

    2016-01-01

    Tamoxifen has been successfully used for treating breast cancer and preventing cancer recurrence. Cytochrome P450 2D6 (CYP2D6) plays a key role in the process of metabolizing tamoxifen to its active moiety, endoxifen. Patients with variants of the CYP2D6 gene may not receive the full benefit of tamoxifen treatment. The CYP2D6*10 variant (the most common variant in Asians) was analyzed to optimize the prescription of tamoxifen in China. To ensure referring clinicians have accurate information for genotype-guided tamoxifen treatment, the Chinese National Center for Clinical Laboratories (NCCL) organized a national proficiency testing (PT) to evaluate the performance of laboratories providing CYP2D6*10 genotyping. Ten genomic DNA samples with CYP2D6 wild-type or CYP2D6*10 variants were validated by PCR-sequencing and sent to 28 participant laboratories. The genotyping results and pharmacogenomic test reports were submitted and evaluated by NCCL experts. Additional information regarding the number of samples tested, the accreditation/certification status, and detecting technology was also requested. Thirty-one data sets were received, with a corresponding analytical sensitivity of 98.2% (548/558 challenges; 95% confidence interval: 96.7-99.1%) and an analytic specificity of 96.5% (675/682; 95% confidence interval: 97.9-99.5%). Overall, 25/28 participants correctly identified CYP2D6*10 status in 10 samples; however, two laboratories made serious genotyping errors. Most of the essential information was included in the 20 submitted CYP2D6*10 test reports. The majority of Chinese laboratories are reliable for detecting the CYP2D6*10 variant; however, several issues revealed in this study underline the importance of PT schemes in continued external assessment and provision of guidelines.

  12. National Prociency Testing Result of CYP2D6*10 Genotyping for Adjuvant Tamoxifen Therapy in China

    PubMed Central

    Lin, Guigao; Zhang, Kuo; Yi, Lang; Han, Yanxi; Xie, Jiehong; Li, Jinming

    2016-01-01

    Tamoxifen has been successfully used for treating breast cancer and preventing cancer recurrence. Cytochrome P450 2D6 (CYP2D6) plays a key role in the process of metabolizing tamoxifen to its active moiety, endoxifen. Patients with variants of the CYP2D6 gene may not receive the full benefit of tamoxifen treatment. The CYP2D6*10 variant (the most common variant in Asians) was analyzed to optimize the prescription of tamoxifen in China. To ensure referring clinicians have accurate information for genotype-guided tamoxifen treatment, the Chinese National Center for Clinical Laboratories (NCCL) organized a national proficiency testing (PT) to evaluate the performance of laboratories providing CYP2D6*10 genotyping. Ten genomic DNA samples with CYP2D6 wild-type or CYP2D6*10 variants were validated by PCR-sequencing and sent to 28 participant laboratories. The genotyping results and pharmacogenomic test reports were submitted and evaluated by NCCL experts. Additional information regarding the number of samples tested, the accreditation/certification status, and detecting technology was also requested. Thirty-one data sets were received, with a corresponding analytical sensitivity of 98.2% (548/558 challenges; 95% confidence interval: 96.7–99.1%) and an analytic specificity of 96.5% (675/682; 95% confidence interval: 97.9–99.5%). Overall, 25/28 participants correctly identified CYP2D6*10 status in 10 samples; however, two laboratories made serious genotyping errors. Most of the essential information was included in the 20 submitted CYP2D6*10 test reports. The majority of Chinese laboratories are reliable for detecting the CYP2D6*10 variant; however, several issues revealed in this study underline the importance of PT schemes in continued external assessment and provision of guidelines. PMID:27603206

  13. Differential Oxidation of Two Thiophene-Containing Regioisomers to Reactive Metabolites by Cytochrome P450 2C9

    PubMed Central

    Rademacher, Peter M; Woods, Caleb M; Huang, Qingbiao; Szklarz, Grazyna D; Nelson, Sidney D

    2012-01-01

    The uricosuric diuretic agent tienilic acid (TA) is a thiophene-containing compound that is metabolized by P450 2C9 to 5-OH-TA. A reactive metabolite of TA also forms a covalent adduct to P450 2C9 that inactivates the enzyme and initiates immune-mediated hepatic injury in humans, purportedly through a thiophene-S-oxide intermediate. The 3-thenoyl regioisomer of TA, tienilic acid isomer (TAI), is chemically very similar and is reported to be oxidized by P450 2C9 to a thiophene-S-oxide, yet it is not a mechanism-based inactivator (MBI) of P450 2C9 and is reported to be an intrinsic hepatotoxin in rats. The goal of the work presented in this manuscript was to identify the reactive metabolites of TA and TAI by the characterization of products derived from P450 2C9-mediated oxidation. In addition, in silico approaches were used to better understand both the mechanisms of oxidation of TA and TAI and/or the structural rearrangements of oxidized thiophene compounds. Incubation of TA with P450 2C9 and NADPH yielded the well-characterized 5-OH-TA metabolite as the major product. However, contrary to previous reports, it was found that TAI was oxidized to two different types of reactive intermediates that ultimately lead to two types of products, a pair of hydroxythiophene/thiolactone tautomers and an S-oxide dimer. Both TA and TAI incorporated 18O from 18O2 into their respective hydroxythiophene/thiolactone metabolites indicating that these products are derived from an arene oxide pathway. Intrinsic reaction coordinate calculations of the rearrangement reactions of the model compound 2-acetylthiophene-S-oxide showed that a 1,5-oxygen migration mechanism is energetically unfavorable and does not yield the 5-OH product, but instead yields a six-membered oxathiine ring. Therefore, arene oxide formation and subsequent NIH-shift rearrangement remains the favored mechanism for formation of 5-OH-TA. This also implicates the arene oxide as the initiating factor in TA induced liver

  14. CYP2D7 Sequence Variation Interferes with TaqMan CYP2D6*15 and *35 Genotyping

    PubMed Central

    Riffel, Amanda K.; Dehghani, Mehdi; Hartshorne, Toinette; Floyd, Kristen C.; Leeder, J. Steven; Rosenblatt, Kevin P.; Gaedigk, Andrea

    2016-01-01

    TaqMan™ genotyping assays are widely used to genotype CYP2D6, which encodes a major drug metabolizing enzyme. Assay design for CYP2D6 can be challenging owing to the presence of two pseudogenes, CYP2D7 and CYP2D8, structural and copy number variation and numerous single nucleotide polymorphisms (SNPs) some of which reflect the wild-type sequence of the CYP2D7 pseudogene. The aim of this study was to identify the mechanism causing false-positive CYP2D6*15 calls and remediate those by redesigning and validating alternative TaqMan genotype assays. Among 13,866 DNA samples genotyped by the CompanionDx® lab on the OpenArray platform, 70 samples were identified as heterozygotes for 137Tins, the key SNP of CYP2D6*15. However, only 15 samples were confirmed when tested with the Luminex xTAG CYP2D6 Kit and sequencing of CYP2D6-specific long range (XL)-PCR products. Genotype and gene resequencing of CYP2D6 and CYP2D7-specific XL-PCR products revealed a CC>GT dinucleotide SNP in exon 1 of CYP2D7 that reverts the sequence to CYP2D6 and allows a TaqMan assay PCR primer to bind. Because CYP2D7 also carries a Tins, a false-positive mutation signal is generated. This CYP2D7 SNP was also responsible for generating false-positive signals for rs769258 (CYP2D6*35) which is also located in exon 1. Although alternative CYP2D6*15 and *35 assays resolved the issue, we discovered a novel CYP2D6*15 subvariant in one sample that carries additional SNPs preventing detection with the alternate assay. The frequency of CYP2D6*15 was 0.1% in this ethnically diverse U.S. population sample. In addition, we also discovered linkage between the CYP2D7 CC>GT dinucleotide SNP and the 77G>A (rs28371696) SNP of CYP2D6*43. The frequency of this tentatively functional allele was 0.2%. Taken together, these findings emphasize that regardless of how careful genotyping assays are designed and evaluated before being commercially marketed, rare or unknown SNPs underneath primer and/or probe regions can impact

  15. CYP2D7 Sequence Variation Interferes with TaqMan CYP2D6 (*) 15 and (*) 35 Genotyping.

    PubMed

    Riffel, Amanda K; Dehghani, Mehdi; Hartshorne, Toinette; Floyd, Kristen C; Leeder, J Steven; Rosenblatt, Kevin P; Gaedigk, Andrea

    2015-01-01

    TaqMan™ genotyping assays are widely used to genotype CYP2D6, which encodes a major drug metabolizing enzyme. Assay design for CYP2D6 can be challenging owing to the presence of two pseudogenes, CYP2D7 and CYP2D8, structural and copy number variation and numerous single nucleotide polymorphisms (SNPs) some of which reflect the wild-type sequence of the CYP2D7 pseudogene. The aim of this study was to identify the mechanism causing false-positive CYP2D6 (*) 15 calls and remediate those by redesigning and validating alternative TaqMan genotype assays. Among 13,866 DNA samples genotyped by the CompanionDx® lab on the OpenArray platform, 70 samples were identified as heterozygotes for 137Tins, the key SNP of CYP2D6 (*) 15. However, only 15 samples were confirmed when tested with the Luminex xTAG CYP2D6 Kit and sequencing of CYP2D6-specific long range (XL)-PCR products. Genotype and gene resequencing of CYP2D6 and CYP2D7-specific XL-PCR products revealed a CC>GT dinucleotide SNP in exon 1 of CYP2D7 that reverts the sequence to CYP2D6 and allows a TaqMan assay PCR primer to bind. Because CYP2D7 also carries a Tins, a false-positive mutation signal is generated. This CYP2D7 SNP was also responsible for generating false-positive signals for rs769258 (CYP2D6 (*) 35) which is also located in exon 1. Although alternative CYP2D6 (*) 15 and (*) 35 assays resolved the issue, we discovered a novel CYP2D6 (*) 15 subvariant in one sample that carries additional SNPs preventing detection with the alternate assay. The frequency of CYP2D6 (*) 15 was 0.1% in this ethnically diverse U.S. population sample. In addition, we also discovered linkage between the CYP2D7 CC>GT dinucleotide SNP and the 77G>A (rs28371696) SNP of CYP2D6 (*) 43. The frequency of this tentatively functional allele was 0.2%. Taken together, these findings emphasize that regardless of how careful genotyping assays are designed and evaluated before being commercially marketed, rare or unknown SNPs underneath primer

  16. Can Helicobacter pylori be eradicated with high-dose proton pump inhibitor in extensive metabolizers with the CYP2C19 genotypic polymorphism?

    PubMed

    Ormeci, A; Emrence, Z; Baran, B; Soyer, O M; Gokturk, S; Evirgen, S; Akyuz, F; Karaca, C; Besisik, F; Kaymakoglu, S; Ustek, D; Demir, K

    2016-05-01

    Proton pump inhibitors (PPI) metabolism and pharmacokinetics are regulated by cytochrome P450 enzymes in the liver. Cytochrome P450 2C19 (CYP2C19) polymorphism plays an import role in the metabolism of PPIs. The three possible genotypes for CYP2C19 each has a distinct effect on the pharmacodynamics of PPIs. Homozygote extensive metabolizers (HomEM) are the most frequent genotype and have two wild-types (non-mutant) (*1/*1) alleles. HomEM is associated with increased enzyme activity, which increases the rate of PPI metabolism. Intragastric pH, which is required for eradication, is lowest in HomEM. In HomEMs, an insufficient increase in intragastric pH results in decreased anti-Helicobacter pylori (HP) efficacy of the antibiotics and, therefore, lower eradication rates. We determined whether the HP eradication rate would increase after high-dose PPI treatment of extensive PPI metabolizers who had been treated unsuccessfully with a standard PPI dose. In our report, increasing the PPI dosage in patients with genotype polymorphisms may be effective on eradication rates. Eradication rates are directly affected by CYP2C19 polymorphisms, and eradication treatments should be planned considering such genotypic polymorphisms. Hence, CYP2C19 genotyping prior to treatment may facilitate determination of the optimum PPI dose to improve the therapeutic outcome. However, further researches are required to confirm this hypothesis. PMID:27212172

  17. Effect of CYP2C19 and CYP3A4 gene polymorphisms on the efficacy of bortezomib-based regimens in patients with multiple myeloma

    PubMed Central

    ZHOU, WEIWEI; AN, GUANGYU; JIAN, YUAN; GUO, HUAN; CHEN, WENMING

    2015-01-01

    Bortezomib is used to treat patients with multiple myeloma. It is primarily metabolized by the enzyme cytochrome P450 (CYP). Variations in the capacity of bortezomib metabolism affect the treatment outcomes and the side-effects experienced by patients. In the present study, polymorphisms in the CYP3A4 and CYP2C19 genes were analyzed by polymerase chain reaction in 56 newly-diagnosed patients with multiple myeloma. The polymorphisms analyzed included the c.681G>A, c.636G>A and c.-806C>T polymorphisms of CYP2C19. The CYP3A4 gene was sequenced after amplification and was classified into normal and mutant types. Associations between the metabolizer genotypes of CYP3A4 and CYP2C19, the therapeutic efficacy of bortezomib-based regimens, and the occurrence of peripheral neuropathy were studied. The results identified no significant differences in gender, serum β2 microglobulin, creatinine, blood albumin, isotypes, and the Durie-Salmon and International Staging System stages between the CYP2C19 poor + intermediate metabolizer types and the extensive + ultrarapid metabolizer types. In addition, it was revealed that the CYP2C19 and CYP3A4 phenotypes did not affect the efficacy of bortezomib-based regimens, nor were they correlated with peripheral neuropathy. Additional large-scale studies are required in order to evaluate the role of CYP enzymes in bortezomib treatments for patients with multiple myeloma. PMID:26622646

  18. Infrared and Ultraviolet Spectra of Diborane(6): B2H6 and B2D6.

    PubMed

    Peng, Yu-Chain; Chou, Sheng-Lung; Lo, Jen-Iu; Lin, Meng-Yeh; Lu, Hsiao-Chi; Cheng, Bing-Ming; Ogilvie, J F

    2016-07-21

    We recorded absorption spectra of diborane(6), B2H6 and B2D6, dispersed in solid neon near 4 K in both mid-infrared and ultraviolet regions. For gaseous B2H6 from 105 to 300 nm, we report quantitative absolute cross sections; for solid B2H6 and for B2H6 dispersed in solid neon, we measured ultraviolet absorbance with relative intensities over a wide range. To assign the mid-infrared spectra to specific isotopic variants, we applied the abundance of (11)B and (10)B in natural proportions; we undertook quantum-chemical calculations of wavenumbers associated with anharmonic vibrational modes and the intensities of the harmonic vibrational modes. To aid an interpretation of the ultraviolet spectra, we calculated the energies of electronically excited singlet and triplet states and oscillator strengths for electronic transitions from the electronic ground state. PMID:27351464

  19. Comprehensive CYP2D6 genotype and adherence affect outcome in breast cancer patients treated with tamoxifen monotherapy.

    PubMed

    Thompson, Alastair M; Johnson, Andrea; Quinlan, Philip; Hillman, Grantland; Fontecha, Marcel; Bray, Susan E; Purdie, Colin A; Jordan, Lee B; Ferraldeschi, Roberta; Latif, Ayshe; Hadfield, Kirsten D; Clarke, Robert B; Ashcroft, Linda; Evans, D Gareth; Howell, Anthony; Nikoloff, Michele; Lawrence, Jeffrey; Newman, William G

    2011-01-01

    The association between CYP2D6 genotype and outcome in breast cancer patients treated with adjuvant tamoxifen remains controversial. We assessed the influence of comprehensive versus limited CYP2D6 genotype in the context of tamoxifen adherence and co-medication in a large cohort of 618 patients. Genotyping of 33 CYP2D6 alleles used two archival cohorts from tamoxifen-treated women with invasive breast cancer (Dundee, n = 391; Manchester, n = 227). Estimates for recurrence-free survival (RFS) were calculated based on inferred CYP2D6 phenotypes using Kaplan-Meier and Cox proportional hazard models, adjusted for nodal status and tumour size. Patients with at least one reduced function CYP2D6 allele (60%) or no functional alleles (6%) had a non-significant trend for worse RFS: hazard ratio (HR) 1.52 (CI 0.98-2.36, P = 0.06). For post-menopausal women on tamoxifen monotherapy, the HR for recurrence in patients with reduced functional alleles was 1.96 (CI 1.05-3.66, P = 0.036). However, RFS analysis limited to four common CYP2D6 allelic variants was no longer significant (P = 0.39). The effect of CYP2D6 genotype was increased by adjusting for adherence to tamoxifen therapy, but not significantly changed when adjusted for co-administration of potent inhibitors of CYP2D6. Comprehensive genotyping of CYP2D6 and adherence to tamoxifen therapy may be useful to identify breast cancer patients most likely to benefit from adjuvant tamoxifen.

  20. Evaluation of CYP2D6 enzyme activity using a Dextromethorphan Breath Test in Women Receiving Adjuvant Tamoxifen

    PubMed Central

    Safgren, Stephanie L.; Suman, Vera J.; Kosel, Matthew L.; Gilbert, Judith A; Buhrow, Sarah A.; Black, John L.; Northfelt, Donald W.; Modak, Anil S.; Rosen, David; Ingle, James N.; Ames, Matthew M.; Reid, Joel M.; Goetz, Matthew P.

    2015-01-01

    Background In tamoxifen-treated patients, breast cancer recurrence differs according to CYP2D6 genotype and endoxifen steady state concentrations (Endx Css). The 13Cdextromethorphan breath test (DM-BT), labeled with 13C at the O-CH3 moiety, measures CYP2D6 enzyme activity. We sought to examine the ability of the DM-BT to identify known CYP2D6 genotypic poor metabolizers and examine the correlation between DMBT and Endx Css. Methods DM-BT and tamoxifen pharmacokinetics were obtained at baseline (b), 3 month (3m) and 6 months (6m) following tamoxifen initiation. Potent CYP2D6 inhibitors were prohibited. The correlation between bDM-BT with CYP2D6 genotype and Endx Css was determined. The association between bDM-BT (where values ≤0.9 is an indicator of poor in vivo CYP2D6 metabolism) and Endx Css (using values ≤ 11.2 known to be associated with poorer recurrence free survival) was explored. Results 91 patients were enrolled and 77 were eligible. CYP2D6 genotype was positively correlated with b, 3m and 6m DMBT (r ranging from 0.457-0. 60 p < 0.001). Both CYP2D6 genotype (r = 0.47; 0.56, p <.0001), and bDM-BT (r=0.60; 0.54; p<.001) were associated with 3m and 6m Endx Css respectively. Seven of 9 patients (78%) with low (≤11.2 nM) 3m Endx Css also had low DM-BT (≤0.9) including 2/2 CYP2D6 PM/PM and 5/5 IM/PM. In contrast, 1 of 48 pts (2%) with a low DM-BT had Endx Css > 11.2 nM. Conclusions In patients not taking potent CYP2D6 inhibitors, DM-BT was associated with CYP2D6 genotype and 3m and 6 m Endx Css but did not provide better discrimination of Endx Css compared to CYP2D6 genotype alone. Further studies are needed to identify additional factors which alter Endx Css. PMID:25714002

  1. Poor Metabolizers at the Cytochrome P450 2C19 Loci Is at Increased Risk of Developing Cancer in Asian Populations

    PubMed Central

    Chen, Zenggan; Yu, Yanmin

    2013-01-01

    Background CYP2C19 encodes a member of the cytochrome P450 superfamily of enzymes, which play a central role in activating and detoxifying many carcinogens and endogenous compounds thought to be involved in the development of cancer. In the past decade, two common polymorphisms among CYP2C19 (CYP2C19*2 and CYP2C19*3) that are responsible for the poor metabolizers (PMs) phenotype in humans and cancer susceptibility have been investigated extensively; however, these studies have yielded contradictory results. Methods and Results To investigate this inconsistency, we conducted a comprehensive meta-analysis of 11,554 cases and 16,592 controls from 30 case-control studies. Overall, the odds ratio (OR) of cancer was 1.52 [95% confidence interval (CI): 1.23–1.88, P<10-4] for CYP2C19 PMs genotypes. However, this significant association vanished when the analyses were restricted to 5 larger studies (no. of cases ≥ 500 cases). In the subgroup analysis for different cancer types, PMs genotypes had an effect of increasing the risks of esophagus cancer, gastric cancer, lung cancer and hepatocellular carcinoma as well as head neck cancer. Significant results were found in Asian populations when stratified by ethnicity; whereas no significant associations were found among Caucasians. Stratified analyses according to source of controls, significant associations were found only in hospital base controls. Conclusions Our meta-analysis suggests that the CYP2C19 PMs genotypes most likely contributes to cancer susceptibility, particularly in the Asian populations. PMID:24015291

  2. Inhibition of CYP2C19 and CYP3A4 by Omeprazole Metabolites and Their Contribution to Drug-Drug Interactions

    PubMed Central

    Shirasaka, Yoshiyuki; Sager, Jennifer E.; Lutz, Justin D.; Davis, Connie

    2013-01-01

    The aim of this study was to evaluate the contribution of metabolites to drug-drug interactions (DDI) using the inhibition of CYP2C19 and CYP3A4 by omeprazole and its metabolites as a model. Of the metabolites identified in vivo, 5-hydroxyomeprazole, 5′-O-desmethylomeprazole, omeprazole sulfone, and carboxyomeprazole had a metabolite to parent area under the plasma concentration–time curve (AUCm/AUCp) ratio ≥ 0.25 when either total or unbound concentrations were measured after a single 20-mg dose of omeprazole in a cocktail. All of the metabolites inhibited CYP2C19 and CYP3A4 reversibly. In addition omeprazole, omeprazole sulfone, and 5′-O-desmethylomeprazole were time dependent inhibitors (TDI) of CYP2C19, whereas omeprazole and 5′-O-desmethylomeprazole were found to be TDIs of CYP3A4. The in vitro inhibition constants and in vivo plasma concentrations were used to evaluate whether characterization of the metabolites affected DDI risk assessment. Identifying omeprazole as a TDI of both CYP2C19 and CYP3A4 was the most important factor in DDI risk assessment. Consideration of reversible inhibition by omeprazole and its metabolites would not identify DDI risk with CYP3A4, and with CYP2C19, reversible inhibition values would only identify DDI risk if the metabolites were included in the assessment. On the basis of inactivation data, CYP2C19 and CYP3A4 inhibition by omeprazole would be sufficient to identify risk, but metabolites were predicted to contribute 30–63% to the in vivo hepatic interactions. Therefore, consideration of metabolites may be important in quantitative predictions of in vivo DDIs. The results of this study show that, although metabolites contribute to in vivo DDIs, their relative abundance in circulation or logP values do not predict their contribution to in vivo DDI risk. PMID:23620487

  3. Effects of mace and nutmeg on human cytochrome P450 3A4 and 2C9 activity.

    PubMed

    Kimura, Yuka; Ito, Hideyuki; Hatano, Tsutomu

    2010-01-01

    Pharmacokinetic or pharmacodynamic interactions between herbal medicines or food constituents and drugs have been studied as crucial factors determining therapeutic efficacy and outcome. Most of these interactions are attributed to inhibition or induction of activity of cytochrome P450 (CYP) metabolic enzymes. Inhibition or induction of CYP enzymes by beverages, including grapefruit, pomegranate, or cranberry juice, has been well documented. Because spices are a common daily dietary component, other studies have reported inhibition of CYP activity by spices or their constituents/derivatives. However, a systematic evaluation of various spices has not been performed. In this study, we investigated effects of 55 spices on CYP3A4 and CYP2C9 activity. Cinnamon, black or white pepper, ginger, mace, and nutmeg significantly inhibited CYP3A4 or CYP2C9 activity. Furthermore, bioassay-guided fractionation of mace (Myristica fragrans) led to isolation and structural characterization of a new furan derivative (1) along with other 16 known compounds, including an acylphenol, neolignans, and phenylpropanoids. Among these isolates, (1S,2R)-1-acetoxy-2-(4-allyl-2,6-dimethoxyphenoxy)-1-(3,4-dimethoxyphenyl)propane (9) exhibited the most potent CYP2C9 inhibitory activity with an IC₅₀ value comparable to that of sulfaphenazole, a CYP2C9 inhibitor. Compound 9 competitively inhibited CYP2C9-mediated 4'-hydroxylation of diclofenac. The inhibitory constant (K(i)) of 9 was determined to be 0.037 µM. Compound 9 was found to be 14-fold more potent than was sulfaphenazole.

  4. Prediction of Warfarin Dose Reductions in Puerto Rican Patients, Based on Combinatorial CYP2C9 and VKORC1 Genotypes

    PubMed Central

    Valentin, Isa Ivette; Vazquez, Joan; Rivera-Miranda, Giselle; Seip, Richard L; Velez, Meredith; Kocherla, Mohan; Bogaard, Kali; Cruz-Gonzalez, Iadelisse; Cadilla, Carmen L; Renta, Jessica Y; Felliu, Juan F; Ramos, Alga S; Alejandro-Cowan, Yirelia; Gorowski, Krystyna; Ruaño, Gualberto; Duconge, Jorge

    2012-01-01

    BACKGROUND The influence of CYP2C9 and VKORC1 polymorphisms on warfarin dose has been investigated in white, Asian, and African American populations but not in Puerto Rican Hispanic patients. OBJECTIVE To test the associations between genotypes, international normalized ratio (INR) measurements, and warfarin dosing and gauge the impact of these polymorphisms on warfarin dose, using a published algorithm. METHODS A retrospective warfarin pharmacogenetic association study in 106 Puerto Rican patients was performed. DNA samples from patients were assayed for 12 variants in both CYP2C9 and VKORC1 loci by HILOmet PhyzioType assay. Demographic and clinical nongenetic data were retrospectively collected from medical records. Allele and genotype frequencies were determined and Hardy-Weinberg equilibrium (HWE) was tested. RESULTS Sixty-nine percent of patients were carriers of at least one polymorphism in either the CYP2C9 or the VKORC1 gene. Double, triple, and quadruple carriers accounted for 22%, 5%, and 1%, respectively. No significant departure from HWE was found. Among patients with a given CYP2C9 genotype, warfarin dose requirements declined from GG to AA haplotypes; whereas, within each VKORC1 haplotype, the dose decreased as the number of CYP2C9 variants increased. The presence of these loss-of-function alleles was associated with more out-of-range INR measurements (OR = 1.38) but not with significant INR >4 during the initiation phase. Analyses based on a published pharmacogenetic algorithm predicted dose reductions of up to 4.9 mg/day in carriers and provided better dose prediction in an extreme subgroup of highly sensitive patients, but also suggested the need to improve predictability by developing a customized model for use in Puerto Rican patients. CONCLUSIONS This study laid important groundwork for supporting a prospective pharmacogenetic trial in Puerto Ricans to detect the benefits of incorporating relevant genomic information into a customized DNA

  5. CYP2C19 and CES1 polymorphisms and efficacy of clopidogrel and aspirin dual antiplatelet therapy in patients with symptomatic intracranial atherosclerotic disease.

    PubMed

    Hoh, Brian L; Gong, Yan; McDonough, Caitrin W; Waters, Michael F; Royster, Adrienne J; Sheehan, Tiffany O; Burkley, Ben; Langaee, Taimour Y; Mocco, J; Zuckerman, Scott L; Mummareddy, Nishit; Stephens, Marcus L; Ingram, Christie; Shaffer, Christian M; Denny, Joshua C; Brilliant, Murray H; Kitchner, Terrie E; Linneman, James G; Roden, Dan M; Johnson, Julie A

    2016-06-01

    OBJECT Symptomatic intracranial atherosclerotic disease (ICAD) has a high risk of recurrent stroke. Genetic polymorphisms in CYP2C19 and CES1 are associated with adverse outcomes in cardiovascular patients, but have not been studied in ICAD. The authors studied CYP2C19 and CES1 single-nucleotide polymorphisms (SNPs) in symptomatic ICAD patients. METHODS Genotype testing for CYP2C19*2, (*)3, (*)8, (*)17 and CES1 G143E was performed on 188 adult symptomatic ICAD patients from 3 medical centers who were medically managed with clopidogrel and aspirin. Testing was performed prospectively at 1 center, and retrospectively from a DNA sample biorepository at 2 centers. Multiple logistic regression and Cox regression analysis were performed to assess the association of these SNPs with the primary endpoint, which was a composite of transient ischemic attack (TIA), stroke, myocardial infarction, or death within 12 months. RESULTS The primary endpoint occurred in 14.9% of the 188 cases. In multiple logistic regression analysis, the presence of the CYP2C19 loss of function (LOF) alleles *2, *3, and *8 in the medically managed patients was associated with lower odds of primary endpoint compared with wild-type homozygotes (odds ratio [OR] 0.13, 95% CI 0.03-0.62, p = 0.0101). Cox regression analysis demonstrated the CYP2C19 LOF carriers had a lower risk for the primary endpoint, with hazard ratio (HR) of 0.27 (95% CI 0.08-0.95), p = 0.041. A sensitivity analysis of a secondary composite endpoint of TIA, stroke, or death demonstrated a significant trend in multiple logistic regression analysis of CYP2C19 variants, with lower odds of secondary endpoint in patients carrying at least 1 LOF allele (*2, *3, *8) than in wild-type homozygotes (OR 0.27, 95% CI 0.06-1.16, p = 0.078). Cox regression analysis demonstrated that the carriers of CYP2C19 LOF alleles had a lower risk forthe secondary composite endpoint (HR 0.22, 95% CI 0.05-1.04, p = 0.056). CONCLUSIONS This is the first study

  6. Effects of 22 novel CYP2D6 variants found in Chinese population on the metabolism of dapoxetine

    PubMed Central

    Xu, Ren-ai; Gu, Er-min; Zhou, Quan; Yuan, Lingjing; Hu, Xiaoxia; Cai, Jianping; Hu, Guoxin

    2016-01-01

    Background CYP2D6 is one of the most important members of the cytochrome P450 superfamily. Its genetic polymorphism significantly influences the efficacy and safety of some drugs, which might cause adverse effects and therapeutic failure. Methods and results The aim of this research was mainly to explore the catalytic activities of 22 newly reported CYP2D6 isoforms (2D6*87, *88, *89, *90, *91, *92, *93, *94, *95, *96,*97, *98, *R25Q, F164L, E215K, F219S, V327M, D336N, V342M, R344Q, R440C, R497C) on dapoxetine in vitro. The research was designed with an appropriate incubation system in test tubes and carried out in the constant temperature water. Through detecting its two metabolites desmethyldapoxetine and dapoxetine-N-oxide, the available data were obtained to explain the influence of CYP2D6 polymorphism on the substrate drug dapoxetine. As a result, the intrinsic clearance (Vmax/Km) values of most variants were significantly altered when compared with the counterpart of CYP2D6*1, with most of these variants exhibiting either reduced Vmax and/or increased Km values. For dapoxetine demethylation pathway (which produces desmethyldapoxetine), 2D6*89 and E215K exhibited no markedly decreased relative clearance of 92.81% and 97.70%, respectively. The relative clearance of rest 20 variants exhibited decrease in different levels, ranging from 20.44% to 90.90%. For the dapoxetine oxidation pathway (which produces dapoxetine-N-oxide), the relative clearance values of three variants, 2D6*90, *94, and V342M, exhibited no markedly increased relative clearance of 106.17%, 107.78%, and 109.98%, respectively; the rest 19 variants exhibited significantly decreased levels ranging from 27.56% to 84.64%. In addition, the kinetic parameters of two CYP2D6 variants (2D6*92 and 2D6*96) could not be detected, due to the defect of the CYP2D6 gene. Conclusion As the first report of all aforementioned alleles for dapoxetine metabolism, these data may help in the clinical assessment of the

  7. Pharmacogenetics and breast cancer endocrine therapy: CYP2D6 as a predictive factor for tamoxifen metabolism and drug response?

    PubMed Central

    Stearns, Vered; Rae, James M.

    2011-01-01

    The identification of genetic polymorphisms that influence the efficacy and safety of therapies for breast cancer may allow future treatments to be individualised based not only on tumour characteristics but also on host genetics. Genetic factors that affect the metabolism, efficacy and safety of tamoxifen, one of the most common drugs used for the treatment and prevention of breast cancer, have received particular attention. Cytochrome P450 2D6 (CYP2D6) is crucial in the metabolism of tamoxifen to its active metabolite endoxifen. Women with genetic variants of CYP2D6 or who take drugs that inhibit the enzyme have low endoxifen plasma concentrations and may show reduced benefits to tamoxifen treatment. CYP2D6 polymorphisms and variants in other candidate genes may also influence secondary benefits and side effects of tamoxifen. Here, we summarise data suggesting that CYP2D6 status may be an important predictor of the benefits of tamoxifen to an individual; in addition, we briefly discuss the role of variants in other candidate genes. Whether CYP2D6 status should be determined prior to initiating tamoxifen therapy is currently under debate and may be appropriate only for select women who are candidates for tamoxifen alone but for whom alternative standard options are available. PMID:19019258

  8. Machine Learning Energies of 2 Million Elpasolite (A B C2D6) Crystals

    NASA Astrophysics Data System (ADS)

    Faber, Felix A.; Lindmaa, Alexander; von Lilienfeld, O. Anatole; Armiento, Rickard

    2016-09-01

    Elpasolite is the predominant quaternary crystal structure (AlNaK2F6 prototype) reported in the Inorganic Crystal Structure Database. We develop a machine learning model to calculate density functional theory quality formation energies of all ˜2 ×106 pristine A B C2D6 elpasolite crystals that can be made up from main-group elements (up to bismuth). Our model's accuracy can be improved systematically, reaching a mean absolute error of 0.1 eV /atom for a training set consisting of 10 ×103 crystals. Important bonding trends are revealed: fluoride is best suited to fit the coordination of the D site, which lowers the formation energy whereas the opposite is found for carbon. The bonding contribution of the elements A and B is very small on average. Low formation energies result from A and B being late elements from group II, C being a late (group I) element, and D being fluoride. Out of 2 ×106 crystals, 90 unique structures are predicted to be on the convex hull—among which is NFAl2Ca6, with a peculiar stoichiometry and a negative atomic oxidation state for Al.

  9. Tamoxifen Metabolite Concentrations, CYP2D6 Genotype and Breast Cancer Outcomes

    PubMed Central

    Madlensky, Lisa; Natarajan, Loki; Tchu, Simone; Pu, Minya; Mortimer, Joanne; Flatt, Shirley W.; Nikoloff, D. Michele; Hillman, Grantland; Fontecha, Marcel R.; Lawrence, H. Jeffrey; Parker, Barbara A.; Wu, Alan H.B.; Pierce, John P.

    2011-01-01

    We explored whether breast cancer outcomes are associated with endoxifen and other metabolites of tamoxifen, and to examine potential correlates of endoxifen concentrations including CYP2D6 metabolizer phenotype and body mass index (BMI). Tamoxifen, endoxifen, 4-hydroxytamoxifen and N-desmethyltamoxifen concentrations were measured from 1370 estrogen receptor positive breast cancer patients participating in the Women’s Healthy Eating and Living (WHEL) Study, and tested for associations with breast cancer outcomes. Breast cancer outcomes were not associated with tamoxifen, 4-hydroxytamoxifen or N-desmethyltamoxifen concentrations. For endoxifen, a threshold was identified suggesting that women in the upper four quintiles of endoxifen had a 26% lower recurrence rate than women in the bottom quintile. (HR=0.74; 95% CI, [0.55, 1.00]). Predictors of membership in this higher risk bottom quintile were poor/intermediate metabolizer genotype, higher BMI, and low tamoxifen concentrations. This study suggests a minimal threshold at which endoxifen is effective against breast cancer recurrence, which 80% of tamoxifen-takers achieve. PMID:21430657

  10. A haplotype of CYP2C9 associated with warfarin sensitivity in mechanical heart valve replacement patients

    PubMed Central

    Lee, Su-Jun; Jang, Yin Jin; Cha, Eun-Young; Kim, Ho-Sook; Lee, Sang Seop; Shin, Jae-Gook

    2010-01-01

    AIMS The objectives of this study were to determine the distribution of CYP2C9 variants in Koreans and investigate their association with warfarin dose requirements in patients who received MHVRs. METHODS All nine exons, intron–exon junction, and promoter region of CYP2C9 were amplified and directly sequenced in 50 healthy normal Koreans. Additional direct DNA sequencing of the CYP2C9 gene was conducted in 36 of the 267 MHVR patients who required low maintenance warfarin doses without carrying CYP2C9*3 and VKORC1 1173T mutations. The effects of CYP2C9 genetics on warfarin maintenance dose were assessed in 267 MHVR patients. RESULTS Thirty-nine single nucleotide polymorphisms (SNPs) including seven previously unidentified SNPs were identified in 50 Koreans by direct DNA sequencing. One of the CYP2C9 haplotypes exhibited an association with warfarin low dose requirement. The adjusted odds ratio for the haplotype between the low dose group and the normal subjects was 2.5 (95% confidence interval 1.05, 6.16). This haplotype consisting of -1565C>T, -1188T>C, IVS3+197G>A, IVS3-334C>T, IVS3-65G>C, IVS4-115A>G, and IVS5-73A>G was found in 15% of 36 MHVR patients who required low warfarin doses, while 4% of 50 normal healthy subjects exhibited this haplotype. One of the SNPs comprising this haplotype, -1565C>T, apparently changed a protein binding pattern as observed in electrophoretic mobility shift assay. CONCLUSION The haplotype including -1565C>T, -1188T>C, IVS3+197G>A, IVS3-334C>T, IVS3-65G>C, IVS4-115A>G, and IVS5-73A>G seems to be associated with low warfarin dose requirement and this haplotype could be considered in the development of a warfarin dose prediction model for Asian populations. PMID:20653674

  11. Therapeutic drug monitoring of voriconazole: a case report of multiple drug interactions in a patient with an increased CYP2C19 activity

    PubMed Central

    2014-01-01

    Background Voriconazole is metabolized by cytochrome P450 (CYP) 2C19 and CYP 3A4. Drug-drug interactions and genetic polymorphisms modulate their activities. Case presentation A 35-year old African female patient with resistant HIV and a cerebral mass of unknown origin was treated with voriconazole for a suspicion of disseminated Aspergillosis infection. Voriconazole trough concentrations (C0) were within target range while the patient was under esomeprazole, a CYP2C19 inhibitor. Phenotyping showed decreased CYP2C19 activity, whereas genotyping showed a variant allele associated with increased enzyme activity. The patient was switched to ranitidine because of the introduction of atazanavir. CYP3A4 inhibition by atazanavir combined with uninhibited CYP2C19 activity resulted in subtherapeutic voriconazole C0. The reintroduction of esomeprazole allowed restoring voriconazole C0 back to target range. Conclusion The integration of drug-drug interactions and pharmacogenetics data is crucial to interpret drug concentrations correctly, thus preventing suboptimal exposure to voriconazole. PMID:25120580

  12. Metabolic activation of clopidogrel: in vitro data provide conflicting evidence for the contributions of CYP2C19 and PON1.

    PubMed

    Polasek, Thomas M; Doogue, Matthew P; Miners, John O

    2011-12-01

    The recent report that clopidogrel efficacy may be more dependent on paraoxonase-1 (PON1) than on cytochrome P450 2C19 (CYP2C19) activity raises questions about the roles of these and other enzymes in clopidogrel activation. To provide insight into the emerging PON1 versus CYP2C19 debate, this commentary summarizes the clinical evidence on the pharmacokinetic determinants of clopidogrel efficacy. We then review the in vitro studies investigating the enzymes involved in clopidogrel activation, and comment on their strengths and limitations. There is agreement amongst in vitro studies regarding the involvement of CYP1A2 and CYP2B6 in the metabolism of clopidogrel to 2-oxo-clopidogrel. However, the evidence for other CYP enzymes in the first activation step (e.g. CYP2C19 and CYP3A4) is inconsistent and dependent on the in vitro test system and laboratory. All major drug metabolizing CYP enzymes are capable of converting 2-oxo-clopidogrel to sulfenic acid intermediates that subsequently form the active thiol metabolite. However, the extent of CYP involvement in this second step has been challenged, and new evidence suggests that CYP-independent hydrolytic cleavage of the thioester bond may be more important than oxidative metabolism.

  13. Effects of cytochrome P450 2C19 and paraoxonase 1 polymorphisms on antiplatelet response to clopidogrel therapy in patients with coronary artery disease.

    PubMed

    Tresukosol, Damrus; Suktitipat, Bhoom; Hunnangkul, Saowalak; Kamkaew, Ruttakarn; Poldee, Saiphon; Tassaneetrithep, Boonrat; Likidlilid, Atip

    2014-01-01

    Clopidogrel is an antiplatelet prodrug that is recommended to reduce the risk of recurrent thrombosis in coronary artery disease (CAD) patients. Paraoxonase 1 (PON1) is suggested to be a rate-limiting enzyme in the conversion of 2-oxo-clopidogrel to active thiol metabolite with inconsistent results. Here, we sought to determine the associations of CYP2C19 and PON1 gene polymorphisms with clopidogrel response and their role in ADP-induced platelet aggregation. Clopidogrel response and platelet aggregation were determined using Multiplate aggregometer in 211 patients with established CAD who received 75 mg clopidogrel and 75-325 mg aspirin daily for at least 14 days. Polymorphisms in CYP2C19 and PON1 were genotyped and tested for association with clopidogrel resistance. Linkage disequilibrium (LD) and their epistatic interaction effects on ADP-induced platelet aggregation were analysed. The prevalence of clopidogrel resistance in this population was approximately 33.2% (n = 70). The frequencies of CYP2C19*2 and *3 were significantly higher in non-responder than those in responders. After adjusting for established risk factors, CYP2C19*2 and *3 alleles independently increased the risk of clopidogrel resistance with adjusted ORs 2.94 (95%CI, 1.65-5.26; p<0.001) and 11.26 (95%CI, 2.47-51.41; p = 0.002, respectively). Patients with *2 or *3 allele and combined with smoking, diabetes and increased platelet count had markedly increased risk of clopidogrel resistance. No association was observed between PON1 Q192R and clopidogrel resistance (adjusted OR = 1.13, 95%CI, 0.70-1.82; p = 0.622). Significantly higher platelet aggregation values were found in CYP2C19*2 and *3 patients when compared with *1/*1 allele carriers (p = 1.98 × 10(-6)). For PON1 Q192R genotypes, aggregation values were similar across all genotype groups (p = 0.359). There was no evidence of gene-gene interaction or LD between CYP2C19 and PON1 polymorphisms on ADP-induced platelet aggregation. Our

  14. Investigation of selective inhibitory effects of glycyrol on human CYP 1A1 and 2C9.

    PubMed

    Kim, Sun Joo; Kim, Su Jin; Hong, Miri; Choi, Hyun Gyu; Kim, Jeong Ah; Lee, Sangkyu

    2016-10-01

    1. Glycyrol is a coumarin derivative isolated from the roots of Glycyrrhiza uralensis called Gamcho in Korea and commonly used as a sweetener in oriental medicine. Glycyrol shows several biological activities, including anti-oxidative, anti-inflammatory, antibacterial, anti-angiogenic, and anti-allergenic properties. Although there have been studies on the biological effects of glycyrol, the inhibitory effects of glycyrol on cytochrome P450 (CYP) activities have not been investigated. 2. We investigated the inhibitory effects of glycyrol on the activities of CYP isoforms using a cocktail of probe substrates in pooled human liver microsome (HLM) and human recombinant cDNA-expressed CYPs. Glycyrol strongly inhibited CYP1A-mediated phenacetin O-deethylation and CYP2C9-mediated diclofenac 4'-hydroxylation in HLMs, which were the result of competitive inhibition as revealed by a Dixon plot. In addition, glycyrol showed selective inhibition of CYP1A1- and CYP1A2-catalyzed phenacetin O-deethylase activity with a half-maximal inhibitory concentration of (IC50) 1.3 and 16.1 μM in human recombinant cDNA-expressed CYP1A1 and CYP1A2, respectively. 3. Glycyrol decreased CYP2C9-catalyzed diclofenac 4'-hydroxylation activity with IC50 values of 0.67 μM in human recombinant cDNA-expressed CYP2C9. This is the first investigation of competitive inhibitory effects on CYP1A1 and CYP2C9 in HLMs. PMID:26750984

  15. Investigation of selective inhibitory effects of glycyrol on human CYP 1A1 and 2C9.

    PubMed

    Kim, Sun Joo; Kim, Su Jin; Hong, Miri; Choi, Hyun Gyu; Kim, Jeong Ah; Lee, Sangkyu

    2016-10-01

    1. Glycyrol is a coumarin derivative isolated from the roots of Glycyrrhiza uralensis called Gamcho in Korea and commonly used as a sweetener in oriental medicine. Glycyrol shows several biological activities, including anti-oxidative, anti-inflammatory, antibacterial, anti-angiogenic, and anti-allergenic properties. Although there have been studies on the biological effects of glycyrol, the inhibitory effects of glycyrol on cytochrome P450 (CYP) activities have not been investigated. 2. We investigated the inhibitory effects of glycyrol on the activities of CYP isoforms using a cocktail of probe substrates in pooled human liver microsome (HLM) and human recombinant cDNA-expressed CYPs. Glycyrol strongly inhibited CYP1A-mediated phenacetin O-deethylation and CYP2C9-mediated diclofenac 4'-hydroxylation in HLMs, which were the result of competitive inhibition as revealed by a Dixon plot. In addition, glycyrol showed selective inhibition of CYP1A1- and CYP1A2-catalyzed phenacetin O-deethylase activity with a half-maximal inhibitory concentration of (IC50) 1.3 and 16.1 μM in human recombinant cDNA-expressed CYP1A1 and CYP1A2, respectively. 3. Glycyrol decreased CYP2C9-catalyzed diclofenac 4'-hydroxylation activity with IC50 values of 0.67 μM in human recombinant cDNA-expressed CYP2C9. This is the first investigation of competitive inhibitory effects on CYP1A1 and CYP2C9 in HLMs.

  16. Monkey liver cytochrome P450 2C9 is involved in caffeine 7-N-demethylation to form theophylline.

    PubMed

    Utoh, Masahiro; Murayama, Norie; Uno, Yasuhiro; Onose, Yui; Hosaka, Shinya; Fujino, Hideki; Shimizu, Makiko; Iwasaki, Kazuhide; Yamazaki, Hiroshi

    2013-12-01

    Caffeine (1,3,7-trimethylxanthine) is a phenotyping substrate for human cytochrome P450 1A2. 3-N-Demethylation of caffeine is the main human metabolic pathway, whereas monkeys extensively mediate the 7-N-demethylation of caffeine to form pharmacological active theophylline. Roles of monkey P450 enzymes in theophylline formation from caffeine were investigated using individual monkey liver microsomes and 14 recombinantly expressed monkey P450 enzymes, and the results were compared with those for human P450 enzymes. Caffeine 7-N-demethylation activity in microsomes from 20 monkey livers was not strongly inhibited by α-naphthoflavone, quinidine or ketoconazole, and was roughly correlated with diclofenac 4'-hydroxylation activities. Monkey P450 2C9 had the highest activity for caffeine 7-N-demethylation. Kinetic analysis revealed that monkey P450 2C9 had a high Vmax/Km value for caffeine 7-N-demethylation, comparable to low Km value for monkey liver microsomes. Caffeine could dock favorably with monkey P450 2C9 modeled for 7-N-demethylation and with human P450 1A2 for 3-N-demethylation. The primary metabolite theophylline was oxidized to 8-hydroxytheophylline in similar ways by liver microsomes and by recombinant P450s in both humans and monkeys. These results collectively suggest a high activity for monkey liver P450 2C9 toward caffeine 7-N-demethylation, whereas, in humans, P450 1A2-mediated caffeine 3-N-demethylation is dominant.

  17. In vivo individual variations in pharmacokinetics of efavirenz in cynomolgus monkeys genotyped for cytochrome P450 2C9.

    PubMed

    Iwasaki, Kazuhide; Kitsugi, Yusuke; Ikeda, Kanami; Yoshikawa, Takahiro; Hosaka, Shinya; Uehara, Shotaro; Uno, Yasuhiro; Utoh, Masahiro; Yamazaki, Hiroshi

    2016-09-01

    Cynomolgus monkeys are used frequently in preclinical studies for new drug development due to their evolutionary closeness to humans. An antiretroviral drug, efavirenz, is a typical probe substrate for human cytochrome P450 (P450) 2B6, but is mainly metabolized by cynomolgus monkey P450 2C9. In this study, plasma concentrations of efavirenz were assessed in six cynomolgus monkeys genotyped for P450 2C9 c.334 A > C (I112L) (three wild-type, one heterozygote and two homozygotes) by high performance liquid chromatography with tandem mass spectrometry. After intravenous administration at a dose of 1.0 mg/kg, biphasic plasma elimination curves of efavirenz were seen in these cynomolgus monkeys. The mean plasma concentration of the primary metabolite 8-hydroxyefavirenz (1 h after treatment, with hydrolysis by β-glucuronidase) in the wild-type group was significantly higher (4.0-fold) than the combined heterozygous and homozygous group mean. The area under the plasma concentration-time curve value of efavirenz in the homozygous group after oral administration at a dose of 2.0 mg/kg was significantly higher (2.0-fold) than the combined wild-type and heterozygous group. These results collectively indicated that P450 2C9 c.334 A > C (I112L) variation was associated with efavirenz metabolic clearance in vivo. Cynomolgus P450 2C9 polymorphism might account for interindividual variations of efavirenz metabolism in cynomolgus monkeys. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27417918

  18. Relationship between genotype for the cytochrome P450 CYP2D6 and susceptibility to ankylosing spondylitis and rheumatoid arthritis.

    PubMed Central

    Beyeler, C; Armstrong, M; Bird, H A; Idle, J R; Daly, A K

    1996-01-01

    OBJECTIVES--To determine whether particular genotypes for the cytochrome P450 enzyme CYP2D6, a polymorphic enzyme, are associated with susceptibility to ankylosing spondylitis (AS) and rheumatoid arthritis (RA), or linked with any specific clinical or familial features of the two conditions. METHODS--CYP2D6 genotypes were determined in 54 patients with AS, 53 patients with RA, and 662 healthy controls. Leucocyte DNA was analysed for the presence of mutations by restriction fragment length polymorphism analysis with the restriction enzyme Xbal and by two separate polymerase chain reaction assays. RESULTS--On the basis of odds ratio (OR), individuals with two inactive CYP2D6 alleles were more susceptible to AS than controls (OR 2.71, 95% confidence interval (CI) 1.04 to 7.08), with a stronger effect for the CYP2D6B allele (OR 4.11, 95% CI 1.54 to 11.0). No significant differences in the distribution of overall genotypes and allele frequencies were observed between RA and controls. No significant relationships were found between the skeletal, extraskeletal or familial features of AS or RA (iritis, psoriasis, inflammatory enteropathy and rheumatoid nodules, kerato-conjunctivitis sicca, pleuritis, rheumatoid and antinuclear factors) and the overall genotype. CONCLUSIONS--Our findings suggest a modest association between homozygosity for inactive CYP2D6 alleles, particularly CYP2D6B alleles, and susceptibility to AS. However, our results fail to demonstrate a genetic link between CYP2D6 genotype and RA. PMID:8572738

  19. Recombinant production of human microsomal cytochrome P450 2D6 in the methylotrophic yeast Pichia pastoris.

    PubMed

    Dietrich, Matthias; Grundmann, Lisa; Kurr, Katja; Valinotto, Laura; Saussele, Tanja; Schmid, Rolf D; Lange, Stefan

    2005-11-01

    Microsomal cytochrome P450 monooxygenases of groups 1-3 are mainly expressed in the liver and play a crucial role in phase 1 reactions of xenobiotic metabolism. The cDNAs encoding human CYP2D6 and human NADPH-P450 oxidoreductase (CPR) were transformed into the methylotrophic yeast Pichia pastoris and expressed with control of the methanol-inducible AOX1 promoter. The determined molecular weights of the recombinant CYP2D6 and CPR closely matched the calculated values of 55.8 and 76.6 kDa. CPR activity was detected by conversion of cytochrome c by using isolated microsomes. Nearly all of the recombinant CYP was composed of the active holoenzyme, as confirmed by reduced CO difference spectra, which showed a single peak at 450 nm. Only by coexpression of human CPR and CYP was CYP2D6 activity obtained. Microsomes containing human CPR and CYP2D6 converted different substrates, such as 3-cyano-7-ethoxycoumarin, parathion and dextrometorphan. The kinetic parameters of dextrometorphan conversion closely matched those of CYP2D6 from other recombinant expression systems and human microsomes. The endogenous NADPH-P450 oxidoreductase of Pichia pastoris seems to be incompatible with human CYP2D6, as expression of CYP2D6 without human CPR did not result in any CYP activity. These recombinant strains provide a novel, easy-to-handle and cheap source for the biochemical characterisation of single microsomal cytochromes, as well as their allelic variants.

  20. Effect of Genetic Variants, Especially CYP2C9 and VKORC1, on the Pharmacology of Warfarin

    PubMed Central

    Fung, Erik; Patsopoulos, Nikolaos A.; Belknap, Steven M.; O’Rourke, Daniel J.; Robb, John F.; Anderson, Jeffrey L.; Shworak, Nicholas W.; Moore, Jason H.

    2014-01-01

    The genes encoding the cytochrome P450 2C9 enzyme (CYP2C9) and vitamin K-epoxide reductase complex unit 1 (VKORC1) are major determinants of anticoagulant response to warfarin. Together with patient demographics and clinical information, they account for approximately one-half of the warfarin dose variance in individuals of European descent. Recent prospective and randomized controlled trial data support pharmacogenetic guidance with their use in warfarin dose initiation and titration. Benefits from pharmacogenetics-guided warfarin dosing have been reported to extend beyond the period of initial dosing, with supportive data indicating benefits to at least 3 months. The genetic effects of VKORC1 and CYP2C9 in African and Asian populations are concordant with those in individuals of European ancestry; however, frequency distribution of allelic variants can vary considerably between major populations. Future randomized controlled trials in multiethnic settings using population-specific dosing algorithms will allow us to further ascertain the generalizability and cost-effectiveness of pharmacogenetics-guided warfarin therapy. Additional genome-wide association studies may help us to improve and refine dosing algorithms and potentially identify novel biological pathways. PMID:23041981

  1. VKORC1 and CYP2C9 Genotype Variations in Relation to Warfarin Dosing in Korean Stroke Patients

    PubMed Central

    Park, Sea Mi; Lee, Jong-Keuk; Chun, Sa Il; Lee, Hae In; Kwon, Sun U.; Kang, Dong-Wha

    2013-01-01

    Background and Purpose Variant alleles of CYP2C9 and VKORC1 account for differences in anticoagulation response. We sought to establish a warfarin dosing formula for individualized target International Normalization Ratio of Prothrombin Times (INRs) using data from single nucleotide polymorphisms (SNPs) in VKORC1 and CYP2C9 in Korean patients. Methods Ischemic stroke patients displaying stable target INR for at least 3 months before enrollment were analyzed. Warfarin and vitamin K levels were measured to adjust for confounders. Phenotypes were defined using the 'warfarin response index' (WRI) defined as INR divided by the daily maintenance warfarin dose. We tested SNPs in CYP2C9 (3 sites: 430C>T (rs1799853), 1075A>C (rs1057910), 1076T>C) and VKORC1 (14 sites: 381C>T, 861C>A (rs17880887), 2653G>C, 3673A>G, 5496G>T, 5808T>G (r17882154), 6009C>T, 6484T>C (rs9934438), 6853C>T (rs17886369), 7566T>C, 8767G>C, 8814T>C, 9041G>A (rs17880624), and 9071G>T) using a standard sequencing method. Multivariate linear regression analysis was applied to establish the formula for warfarin dosage. Results All 204 patients had excellent drug compliance. The mean INR was 2.22 (+0.56) and mean daily maintenance dose of warfarin was 3.92 mg (+1.54). Patients with low WRI were younger (P<0.001) with high body mass index (P=0.003), high prevalence of wild-type CYP2C9 polymorphism (1075A>C, P<0.001), and six heterozygote SNPs in VRORC1 (P<0.001), which were tightly interlinked (381T>C, 3673G>A, 6484T>C, 6853C>G. 7566C>T, 9041G>A) (r2=1). Based on these data, a warfarin dosing formula was established. Conclusions WRI is influenced by age, body mass index and SNPs in VKORC1 and CYP2C9 in Korean stroke patients. The obtained warfarin dosing formula may be clinically applicable. PMID:24324947

  2. Aloe vera juice: IC₅₀ and dual mechanistic inhibition of CYP3A4 and CYP2D6.

    PubMed

    Djuv, Ane; Nilsen, Odd Georg

    2012-03-01

    The aim of this study was to evaluate the inhibitory potency (IC₅₀ values) of ethanol extracts of two commercially available aloe vera juice (AVJ) products, on CYP3A4 and CYP2D6 activities in vitro and to determine if such inhibitions could be mechanism-based. Recombinant human CYP3A4 and CYP2D6 enzymes were used and the activities were expressed by the metabolism of testosterone and dextromethorphan with ketoconazole and quinidine as positive inhibitor controls, respectively. The formed metabolites were quantified by validated HPLC techniques. Time- and NADPH- dependent inhibition assays were performed to evaluate a possible mechanism-based inhibition. One of the AVJ extracts showed about twice the inhibitory potency towards both CYP enzymes over the other with IC₅₀ values of 8.35 ± 0.72 and 12.5 ± 2.1 mg/mL for CYP3A4 and CYP2D6, respectively. The AVJ was found to exert both CYP mediated and non-CYP mediated inhibition of both CYP3A4 and CYP2D6. This dual mechanistic inhibition, however, seems to be governed by different mechanisms for CYP3A4 and CYP2D6. Estimated IC₅₀ inhibition values indicate no major interference of AVJ with drug metabolism in man, but the dual mechanistic inhibition of both enzymes might be of clinical significance.

  3. A Rapid and Accurate Method to Evaluate Helicobacter pylori Infection, Clarithromycin Resistance, and CYP2C19 Genotypes Simultaneously From Gastric Juice

    PubMed Central

    Kuo, Chao-Hung; Liu, Chung-Jung; Yang, Ching-Chia; Kuo, Fu-Chen; Hu, Huang-Ming; Shih, Hsiang-Yao; Wu, Meng-Chieh; Chen, Yen-Hsu; Wang, Hui-Min David; Ren, Jian-Lin; Wu, Deng-Chyang; Chang, Lin-Li

    2016-01-01

    Abstract Because Helicobacter pylori (H pylori) would cause carcinogenesis of the stomach, we need sufficient information for deciding on an appropriate strategy of eradication. Many factors affect the efficacy of eradication including antimicrobial resistance (especially clarithromycin resistance) and CYP2C19 polymorphism. This study was to survey the efficiency of gastric juice for detecting H pylori infection, clarithromycin resistance, and CYP2C19 polymorphism. The specimens of gastric juice were collected from all patients while receiving gastroscopy. DNA was extracted from gastric juice and then urease A and cag A were amplified by polymerase chain reaction (PCR) for detecting the existence of H pylori. By PCR-restriction fragment length polymorphism (PCR-RFLP), the 23S rRNA of H pylori and CYP2C19 genotypes of host were examined respectively. During endoscopy examination, biopsy-based specimens were also collected for rapid urease test, culture, and histology. The blood samples were also collected for analysis of CYP2C19 genotypes. We compared the results of gastric juice tests with the results of traditional clinical tests. When compared with the results from traditional clinical tests, our results from gastric juice showed that the sensitivity (SEN), specificity (SPE), positive predictive value (PPV), negative predictive value (NPV), and accuracy to detect H pylori infection were 92.1% (105/114), 92.9% (143/154), 90.5% (105/116), 94.1% (143/152), and 92.5% (248/268), respectively. The SEN, SPE, PPV, and NPV to detect clarithromycin resistance were 97.3% (36/37), 91.5% (43/47), 90.0% (36/40), and 97.7% (43/44), respectively. By using PCR-RFLP, the consistency of human CYP2C19 gene polymorphism from blood samples and gastric juice was as high as 94.9% (149/157). The manipulated gastric juice is actually an effective diagnostic sample for evaluation of H pylori existence, clarithromycin resistance, and host CYP2C19 polymorphism. PMID:27227911

  4. YouScript IMPACT Registry

    ClinicalTrials.gov

    2015-09-10

    Adverse Drug Events; Adverse Drug Reactions; Drug Interaction Potentiation; Drug Metabolism, Poor, CYP2D6-RELATED; Drug Metabolism, Poor, CYP2C19-RELATED; Cytochrome P450 Enzyme Deficiency; Cytochrome P450 CYP2D6 Enzyme Deficiency; Cytochrome P450 CYP2C9 Enzyme Deficiency; Cytochrome P450 CYP2C19 Enzyme Deficiency; Cytochrome P450 CYP3A Enzyme Deficiency; Poor Metabolizer Due to Cytochrome P450 CYP2C9 Variant; Poor Metabolizer Due to Cytochrome P450 CYP2C19 Variant; Poor Metabolizer Due to Cytochrome P450 CYP2D6 Variant

  5. Pharmacogenetic Testing Among Home Health Patients

    ClinicalTrials.gov

    2016-09-20

    Adverse Drug Events; Adverse Drug Reactions; Drug Interaction Potentiation; Drug Metabolism, Poor, CYP2D6-RELATED; Drug Metabolism, Poor, CYP2C19-RELATED; Cytochrome P450 Enzyme Deficiency; Cytochrome P450 CYP2D6 Enzyme Deficiency; Cytochrome P450 CYP2C9 Enzyme Deficiency; Cytochrome P450 CYP2C19 Enzyme Deficiency; Cytochrome P450 CYP3A Enzyme Deficiency; Poor Metabolizer Due to Cytochrome P450 CYP2C9 Variant; Poor Metabolizer Due to Cytochrome p450 CYP2C19 Variant; Poor Metabolizer Due to Cytochrome P450 CYP2D6 Variant

  6. CYP2D6 P34S Polymorphism and Outcomes of Escitalopram Treatment in Koreans with Major Depression

    PubMed Central

    Han, Kyu-Man; Chang, Hun Soo; Choi, In-Kwang; Ham, Byung-Joo

    2013-01-01

    Objective Cytochrome P450 (CYP) enzymatic activity, which is influenced by CYP genetic polymorphism, is known to affect the inter-individual variation in the efficacy and tolerability of antidepressants in major depressive disorder (MDD). Escitalopram is metabolized by CYP2D6, and recent studies have reported a correlation between clinical outcomes and CYP2D6 genetic polymorphism. The purpose of this study was to determine the relationship between the CYP2D6 P34S polymorphism (C188T, rs1065852) and the efficacy of escitalopram treatment in Korean patients with MDD. Methods A total of 94 patients diagnosed with MDD were recruited for the study and their symptoms were evaluated using the 21-item Hamilton Depression Rating scale (HAMD-21). The association between the CYP2D6 P34S polymorphism and the clinical outcomes (remission and response) was investigated after 1, 2, 4, 8, and 12 weeks of escitalopram treatment using multiple logistic regression analysis and χ2 test. Results The proportion of P allele carriers (PP, PS) in remission status was greater than that of S allele homozygotes (SS) after 8 and 12 weeks of escitalopram treatment. Similarly, P allele carriers exhibited a greater treatment response after 8 and 12 weeks of escitalopram treatment than S allele homozygotes. Conclusion Our results suggest that the P allele of the CYP2D6 P34S polymorphism is a favorable factor in escitalopram treatment for MDD, and that the CYP2D6 P34S polymorphism may be a good genetic marker for predicting escitalopram treatment outcomes. PMID:24302953

  7. Cure of refractory duodenal ulcer and infection caused by Helicobacter pylori by high doses of omeprazole and amoxicillin in a homozygous CYP2C19 extensive metabolizer patient.

    PubMed

    Furuta, T; Takashima, M; Shirai, N; Xiao, F; Hanai, H; Ohashi, K; Ishizaki, T

    2000-06-01

    A 53-year old female patient with duodenal ulcer and Helicobacter pylori infection was treated three times with a proton pump inhibitor-based triple therapy, such as lansoprazole-clarithromycin-amoxicillin (INN, amoxicilline) and lansoprazole-minocycline-cefaclor. However, the H pylori infection was not cured. A culture test revealed that her infection was a clarithromycin-resistant but amoxicillin-sensitive strain of H pylori. Moreover, a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis revealed that she was a homozygous extensive metabolizer of cytochrome P450 (CYP) 2C19 (wt/wt). The usual dose of the proton pump inhibitor was therefore assumed to be insufficient for her and then she was treated with a high dose of omeprazole (120 mg/day) and amoxicillin (2,250 mg/day) for 2 weeks. The H pylori infection and the ulcer lesion were then cured. One of the factors associated with success or failure of cure of H pylori infection by the proton pump inhibitor-based triple therapy appeared to be CYP2C19 genotype status. Dual treatment with a sufficient dose of a proton pump inhibitor plus amoxicillin could cure H pylori infection even after the failure to cure H pylori infection by a usual proton pump inhibitor-based triple therapy in patients with the wt/wt homozygous extensive metabolizer genotype of CYP2C19.

  8. The effect of induction of CYP3A4 by St John's wort on ambrisentan plasma pharmacokinetics in volunteers of known CYP2C19 genotype.

    PubMed

    Markert, Christoph; Kastner, Ida Maria; Hellwig, Regina; Kalafut, Peter; Schweizer, Yvonne; Hoffmann, Michael Marcus; Burhenne, Jürgen; Weiss, Johanna; Mikus, Gerd; Haefeli, Walter Emil

    2015-05-01

    To evaluate the impact of CYP2C19 polymorphisms on ambrisentan exposure and to assess its modification by St. John's wort (SJW), 20 healthy volunteers (10 CYP2C19 extensive, four poor and six ultrarapid metabolizers) received therapeutic doses of ambrisentan (5 mg qd po) for 20 days and concomitantly SJW (300 mg tid po) for the last 10 days. To quantify changes of CYP3A4 activity, midazolam (3 mg po) as a probe drug was used. Ambrisentan pharmacokinetics was assessed on days 1, 10 and 20, and midazolam pharmacokinetics before and on days 1, 10, 17 and 20. At steady state, ambrisentan exposure was similar in extensive and ultrarapid metabolizers but 43% larger in poor metabolizers (p < 0.01). In all volunteers, SJW reduced ambrisentan exposure and the relative change (17-26%) was similar in all genotype groups. The extent of this interaction did not correlate with the changes in CYP3A activity (midazolam clearance) (rs = 0.23, p = 0.34). Ambrisentan had no effect on midazolam pharmacokinetics. In conclusion, SJW significantly reduced exposure with ambrisentan irrespective of the CYP2C19 genotype. The extent of this interaction was small and thus likely without clinical relevance.

  9. Effect of atorvastatin on CYP2C9 metabolic activity as measured by the formation rate of losartan metabolite in hypercholesterolaemic patients.

    PubMed

    Yasar, Umit; Sain-Guven, Gulay; Yardimci, Yildiz; Kilicarslan, Alpaslan; Babaoglu, Melih O; Bozkurt, Atilla

    2011-08-01

    HMG-CoA reductase inhibitors (statins) have a potential to interact with substrates of the drug-metabolizing enzyme cytochrome P450 2C9 (CYP2C9). This may lead to concentration-dependent toxicity such as skeletal muscle side effects. Atorvastatin, a widely used statin, is presently inadequately investigated in vivo with regard to effects on CYP2C9 activity in human beings. The aim of this study was to determine the effect of atorvastatin on the activity of CYP2C9 in a group of Turkish hypercholesterolaemic patients. We prospectively investigated the atorvastatin effect on CYP2C9 activity in a sample of Turkish hypercholesterolaemia patients (11 women, 7 men) who commenced atorvastatin (10 mg/day). Losartan was used as a probe drug to determine CYP2C9 metabolic activity. A single 25-mg oral dose of losartan was given to the patients before, on the first day and after the fourth week of the atorvastatin treatment. Urinary concentrations of losartan and its metabolite, E3174, were measured by high-pressure liquid chromatography (HPLC). Urinary losartan/E3174 ratios were used as an index of CYP2C9 activity. As the baseline enzyme activity may influence the extent of drug-drug interactions, the CYP2C9*2 and 2C9*3 alleles were identified by using PCR-RFLP. In the patients with the CYP2C9*1*1 genotype (n = 12), atorvastatin treatment did not cause a significant change in losartan/E3174 ratios (medians; 95% CI) neither after the first day (0.73; 0.34-1.61) nor at the fourth week (0.71; 0.36-1.77) of the treatment as compared with the baseline activity (0.92; 0.57-1.74, p = 0.38). Similarly, no significant change in the baseline CYP2C9 activity (0.91; 0.30-1.60) was observed in patients with the CYP2C9*1*2 genotype as compared with those of the first day (1.08; 0.08-2.72) and fourth week (0.64; 0.0-3.82) of the atorvastatin treatment (n = 4, p = 0.86). These observations in a hypercholesterolaemic patient sample suggest that atorvastatin does not have a significant effect

  10. Relationship between Genotypes Sult1a2 and Cyp2d6 and Tamoxifen Metabolism in Breast Cancer Patients

    PubMed Central

    Fernández-Santander, Ana; Gaibar, María; Novillo, Apolonia; Romero-Lorca, Alicia; Rubio, Margarita; Chicharro, Luis Miguel; Tejerina, Armando; Bandrés, Fernando

    2013-01-01

    Tamoxifen is a pro-drug widely used in breast cancer patients to prevent tumor recurrence. Prior work has revealed a role of cytochrome and sulfotransferase enzymes in tamoxifen metabolism. In this descriptive study, correlations were examined between concentrations of tamoxifen metabolites and genotypes for CYP2D6, CYP3A4, CYP3A5, SULT1A1, SULT1A2 and SULT1E1 in 135 patients with estrogen receptor-positive breast cancer. Patients were genotyped using the Roche-AmpliChip® CYP450 Test, and Real-Time and conventional PCR-RFLP. Plasma tamoxifen, 4-hydroxy-tamoxifen, N-desmethyl-tamoxifen, endoxifen and tamoxifen-N-oxide were isolated and quantified using a high-pressure liquid chromatography-tandem mass spectrometry system. Significantly higher endoxifen levels were detected in patients with the wt/wt CYP2D6 compared to the v/v CYP2D6 genotype (p<0.001). No differences were detected in the remaining tamoxifen metabolites among CYP2D6 genotypes. Patients featuring the SULT1A2*2 and SULT1A2*3 alleles showed significantly higher plasma levels of 4-hydroxy-tamoxifen and endoxifen (p = 0.025 and p = 0.006, respectively), as likely substrates of the SULT1A2 enzyme. Our observations indicate that besides the CYP2D6 genotype leading to tamoxifen conversion to potent hydroxylated metabolites in a manner consistent with a gene-dose effect, SULT1A2 also seems to play a role in maintaining optimal levels of both 4-hydroxy-tamoxifen and endoxifen. PMID:23922954

  11. Molecular study of weight gain related to atypical antipsychotics: clinical implications of the CYP2D6 genotype.

    PubMed

    Nussbaum, Laura Alexandra; Dumitraşcu, Victor; Tudor, Anca; Grădinaru, Raluca; Andreescu, Nicoleta; Puiu, Maria

    2014-01-01

    Atypical antipsychotics, especially some of them, influence cellular lipogenesis, being associated with metabolic side effects including weight gain. Due to the increasing use of atypical antipsychotics in children and adolescents, their metabolic and endocrine adverse effects are of particular concern especially within this pediatric population that appears to be at greater risk. Genetic factors with a possible influence on atypical antipsychotics adverse effects include CYP2D6 polymorphisms. Our study, performed in 2009-2014, with a two-year enrolment period during which we recruited children and adolescents with a diagnosis of schizophrenia or bipolar disorder on treatment with the antipsychotics (Risperidone, Aripiprazole or Olanzapine), included 81 patients, aged between 9 and 20 years, median age being 15.74 years. The gender percentage was 54% girls/46% boys. The CYP2D6 genotyping was performed after enrolment of the last patient. Based on the CYP2D6 genotype, three activity groups were identified and compared and we found that the patients with wt/*4 genotype, intermediary metabolizer (carrier of one functional and one non-functional allele) have significantly higher weight gain values than the patients who did not exhibit allele *4. The CYP2D6 genotype in children and adolescents with schizophrenia and bipolar disorder, proved to be a good predictor for the response to atypical antipsychotics and the side effects registered. The significant correlations between the CYP2D6 polymorphisms and the weight gain/BMI (body mass index) increase, as major side effects induced by antipsychotics proved the fact that the pharmacogenetic screening is needed in the future clinical practice, allowing for individualized, tailored treatment, especially for at-risk individuals. PMID:25329115

  12. P450 (Cytochrome) Oxidoreductase Gene (POR) Common Variant (POR*28) Significantly Alters CYP2C9 Activity in Swedish, But Not in Korean Healthy Subjects.

    PubMed

    Hatta, Fazleen H M; Aklillu, Eleni

    2015-12-01

    CYP2C9 enzyme contributes to the metabolism of several pharmaceuticals and xenobiotics and yet displays large person-to-person and interethnic variation. Understanding the mechanisms of CYP2C9 variation is thus of immense importance for personalized medicine and rational therapeutics. A genetic variant of P450 (cytochrome) oxidoreductase (POR), a CYP450 redox partner, is reported to influence CYP2C9 metabolic activity in vitro. We investigated the impact of a common variant, POR*28, on CYP2C9 metabolic activity in humans. 148 healthy Swedish and 146 healthy Korean volunteers were genotyped for known CYP2C9 defective variant alleles (CYP2C9*2, *3). The CYP2C9 phenotype was determined using a single oral dose of 50 mg losartan. Excluding oral contraceptive (OC) users and carriers of 2C9*2 and *3 alleles, 117 Korean and 65 Swedish were genotyped for POR*5, *13 and *28 using Taqman assays. The urinary losartan to its metabolite E-3174 metabolic ratio (MR) was used as an index of CYP2C9 metabolic activity. The allele frequency of the POR*28 variant allele in Swedes and Koreans was 29% and 44%, respectively. POR*5 and *13 were absent in both study populations. Considering the CYP2C9*1/*1 genotypes only, the CYP2C9 metabolic activity was 1.40-fold higher in carriers of POR*28 allele than non-carriers among Swedes (p = 0.02). By contrast, no influence of the POR*28 on CYP2C9 activity was found in Koreans (p = 0.68). The multivariate analysis showed that ethnicity, POR genotype, and smoking were strong predictors of CYP2C9 MR (p < 0.05). This is the first report to implicate the importance of POR*28 genetic variation for CYP2C9 metabolic activity in humans. These findings contribute to current efforts for global personalized medicine and using medicines by taking into account pharmacogenetic and phenotypic variations. PMID:26669712

  13. Drug & Gene Interaction Risk Analysis With & Without Genetic Testing Among Patients Undergoing MTM

    ClinicalTrials.gov

    2016-09-20

    Cytochrome P450 CYP2D6 Enzyme Deficiency; Poor Metabolizer Due to Cytochrome P450 CYP2D6 Variant; Ultrarapid Metabolizer Due to Cytochrome P450 CYP2D6 Variant; Extensive Metabolizer Due to Cytochrome P450 CYP2D6 Variant; Cytochrome P450 CYP2C9 Enzyme Deficiency; Cytochrome P450 CYP2C19 Enzyme Deficiency; Drug Metabolism, Poor, CYP2D6-RELATED; Drug Metabolism, Poor, CYP2C19-RELATED; CYP2D6 Polymorphism

  14. Evaluation of cytochrome P450 2C9 activity in normal, healthy, adult Western Indian population by both phenotyping and genotyping

    PubMed Central

    Swar, Balkrishna D.; Bendkhale, Shital R.; Rupawala, Abbas; Sridharan, Kannan; Gogtay, Nithya J.; Thatte, Urmila M.; Kshirsagar, Nilima A.

    2016-01-01

    Objectives: Cytochrome P450 2C9 (CYP2C9) is a member of cytochrome P450 (CYP) family that accounts for nearly 18% of the total CYP protein content in the human liver microsomes and catalyzes almost 15–20% of the drugs. Considering the paucity of data on the polymorphisms of CYP2C9 in Western Indian population, the present study was conducted to evaluate the prevalence of CYP2C9 polymorphisms (*1, *2 and *3) and correlate it with the activity using flurbiprofen (FLB) as a probe drug. Materials and Methods: A 100 mg FLB capsule was administered to 298 healthy adult participants. Venous blood samples were analyzed at 2 h postdose for the estimation of FLB and 4-hydroxy FLB. Metabolic ratio (MR) was calculated to determine the extent of poor metabolizer (PM) and rapid metabolizer status using probit plot. Genotyping of CYP2C9 polymorphism was performed using polymerase chain reaction-restriction fragment length polymorphism technique. Results: Of the total 298 participants, phenotype was assessable in 288 and genotype was performed in 289 participants. The median (range) MR of the study population was 6.6 (1.65–66.05). Five participants were found to be PMs by phenotype. Of the total 289 participants, 209 (72.3%) (66.7, 77.2) had CYP2C9*1/*1, 25 (8.7%) (5.8, 12.7) with CYP2C9*1/*2, 55 (19%) (14.8, 24.1) had CYP2C9*1/*3, 3 (1%) (0.3, 3.3) had CYP2C9*2/*3 genotype. A significant association between phenotype and genotype was observed. Conclusion: To conclude, the present study found significant association of CYP2C9 activity by both phenotype and genotype and these findings have to be corroborated in different kinds of patients. PMID:27298492

  15. Quantum mechanics/molecular mechanics modeling of regioselectivity of drug metabolism in cytochrome P450 2C9.

    PubMed

    Lonsdale, Richard; Houghton, Kerensa T; Żurek, Jolanta; Bathelt, Christine M; Foloppe, Nicolas; de Groot, Marcel J; Harvey, Jeremy N; Mulholland, Adrian J

    2013-05-29

    Cytochrome P450 enzymes (P450s) are important in drug metabolism and have been linked to adverse drug reactions. P450s display broad substrate reactivity, and prediction of metabolites is complex. QM/MM studies of P450 reactivity have provided insight into important details of the reaction mechanisms and have the potential to make predictions of metabolite formation. Here we present a comprehensive study of the oxidation of three widely used pharmaceutical compounds (S-ibuprofen, diclofenac, and S-warfarin) by one of the major drug-metabolizing P450 isoforms, CYP2C9. The reaction barriers to substrate oxidation by the iron-oxo species (Compound I) have been calculated at the B3LYP-D/CHARMM27 level for different possible metabolism sites for each drug, on multiple pathways. In the cases of ibuprofen and warfarin, the process with the lowest activation energy is consistent with the experimentally preferred metabolite. For diclofenac, the pathway leading to the experimentally observed metabolite is not the one with the lowest activation energy. This apparent inconsistency with experiment might be explained by the two very different binding modes involved in oxidation at the two competing positions. The carboxylate of diclofenac interacts strongly with the CYP2C9 Arg108 side chain in the transition state for formation of the observed metabolite-but not in that for the competing pathway. We compare reaction barriers calculated both in the presence and in the absence of the protein and observe a marked improvement in selectivity prediction ability upon inclusion of the protein for all of the substrates studied. The barriers calculated with the protein are generally higher than those calculated in the gas phase. This suggests that active-site residues surrounding the substrate play an important role in controlling selectivity in CYP2C9. The results show that inclusion of sampling (particularly) and dispersion effects is important in making accurate predictions of drug

  16. Acenocoumarol sensitivity and pharmacokinetic characterization of CYP2C9 *5/*8,*8/*11,*9/*11 and VKORC1*2 in black African healthy Beninese subjects.

    PubMed

    Allabi, Aurel Constant; Horsmans, Yves; Alvarez, Jean-Claude; Bigot, André; Verbeeck, Roger K; Yasar, Umit; Gala, Jean-Luc

    2012-06-01

    This study aimed at investigating the contribution of CYP2C9 and VKORC1 genetic polymorphisms to inter-individual variability of acenocoumarol pharmacokinetics and pharmacodynamics in Black Africans from Benin. Fifty-one healthy volunteers were genotyped for VKORC1 1173C>T polymorphism. All of the subjects had previously been genotyped for CYP2C9*5, CYP2C9*6, CYP2C9*8, CYP2C9*9 and CYP2C9*11 alleles. Thirty-six subjects were phenotyped with a single 8 mg oral dose of acenocoumarol by measuring plasma concentrations of (R)- and (S)-acenocoumarol 8 and 24 h after the administration using chiral liquid-chromatography tandem mass-spectrometry. International normalized ratio (INR) values were determined prior to and 24 h after the drug intake. The allele frequency of VKORC1 variant (1173C>T) was 1.96% (95% CI 0.0-4.65%). The INR values did not show statistically significant difference between the CYP2C9 genotypes, but were correlated with body mass index and age at 24 h post-dosing (P < 0.05). At 8 h post dose, the (S)-acenocoumarol concentrations in the CYP2C9*5/*8 and CYP2C9*9/*11 genotypes were about 1.9 and 5.1 fold higher compared with the CYP2C9*1/*1 genotype and 2.2- and 6.0-fold higher compared with the CYP2C9*1/*9 group, respectively. The results indicated that pharmacodynamic response to acenocoumarol is highly variable between the subjects. This variability seems to be associated with CYP2C9*5/*8 and *9/*11 variant and demographic factors (age and weight) in Beninese subjects. Significant association between plasma (S)-acenocoumarol concentration and CYP2C9 genotypes suggested the use of (S)-acenocoumarol for the phenotyping purpose. Larger number of subjects is needed to study the effect of VKORC1 1173C>T variant due to its low frequency in Beninese population. PMID:21811894

  17. Physiologically based pharmacokinetic modeling for sequential metabolism: effect of CYP2C19 genetic polymorphism on clopidogrel and clopidogrel active metabolite pharmacokinetics.

    PubMed

    Djebli, Nassim; Fabre, David; Boulenc, Xavier; Fabre, Gérard; Sultan, Eric; Hurbin, Fabrice

    2015-04-01

    Clopidogrel is a prodrug that needs to be converted to its active metabolite (clopi-H4) in two sequential cytochrome P450 (P450)-dependent steps. In the present study, a dynamic physiologically based pharmacokinetic (PBPK) model was developed in Simcyp for clopidogrel and clopi-H4 using a specific sequential metabolite module in four populations with phenotypically different CYP2C19 activity (poor, intermediate, extensive, and ultrarapid metabolizers) receiving a loading dose of 300 mg followed by a maintenance dose of 75 mg. This model was validated using several approaches. First, a comparison of predicted-to-observed area under the curve (AUC)0-24 obtained from a randomized crossover study conducted in four balanced CYP2C19-phenotype metabolizer groups was performed using a visual predictive check method. Second, the interindividual and intertrial variability (on the basis of AUC0-24 comparisons) between the predicted trials and the observed trial of individuals, for each phenotypic group, were compared. Finally, a further validation, on the basis of drug-drug-interaction prediction, was performed by comparing observed values of clopidogrel and clopi-H4 with or without dronedarone (moderate CYP3A4 inhibitor) coadministration using a previously developed and validated physiologically based PBPK dronedarone model. The PBPK model was well validated for both clopidogrel and its active metabolite clopi-H4, in each CYP2C19-phenotypic group, whatever the treatment period (300-mg loading dose and 75-mg last maintenance dose). This is the first study proposing a full dynamic PBPK model able to accurately predict simultaneously the pharmacokinetics of the parent drug and of its primary and secondary metabolites in populations with genetically different activity for a metabolizing enzyme.

  18. CYP2D6 Metabolism and Patient Outcome in the Austrian Breast and Colorectal Cancer Study Group Trial (ABCSG) 8

    PubMed Central

    Goetz, Matthew P.; Suman, Vera J.; Hoskin, Tanya L.; Gnant, Michael; Filipits, Martin; Safgren, Stephanie L.; Kuffel, Mary; Jakesz, Raimund; Rudas, Margaretha; Greil, Richard; Dietze, Otto; Lang, Alois; Offner, Felix; Reynolds, Carol A.; Weinshilboum, Richard M.; Ames, Matthew M.; Ingle, James N.

    2012-01-01

    Background Controversy exists regarding CYP2D6 genotype and tamoxifen efficacy. Methods A matched case-control study was conducted utilizing the Austrian Breast and Colorectal Cancer Study Group Trial 8 that randomized post-menopausal women with estrogen receptor positive breast cancer to tamoxifen for 5 years (Arm A) or tamoxifen for 2 years followed by anastrozole for 3 years (Arm B). Cases had disease recurrence, contralateral breast cancer, second non-breast cancer, or died. For each case, controls were identified from the same treatment arm of similar age, surgery/radiation, and TNM stage. Genotyping was performed for alleles associated with no (PM; *3, *4, *6); reduced (IM; *10, and *41); and extensive (EM: absence of these alleles) CYP2D6 metabolism. Findings The common CYP2D6 *4 allele was in Hardy Weinberg Equilibrium. In Arm A during the first 5 years of therapy, women with 2 poor alleles (PM/PM: OR=2.45, 95% CI: 1.05–5.73, p=0.04) and women with one poor allele (PM/IM or PM/EM: OR=1.67, 95% CI: 0.95–2.93, p=0.07) had a higher likelihood of an event than women with two extensive alleles (EM/EM). In years 3–5 when patients remained on tamoxifen (Arm A) or switched to anastrozole (Arm B), PM/PM tended towards a higher likelihood of a disease event relative to EM/EM (OR= 2.40, 95% CI: 0.86–6.66, p=0.09) among women on Arm A but not among women on Arm B (OR= 0.28; 95% CI: 0.03–2.30). Conclusion In ABCSG8, the negative effects of reduced CYP2D6 metabolism were observed only during the period of tamoxifen administration, and not after switching to anastrozole. PMID:23213055

  19. Surface-enhanced resonance Raman scattering of cytochrome P450-2D6 on coated silver hydrosols.

    PubMed

    Bonifacio, Alois; Keizers, Peter H J; Vermeulen, Nico P E; Commandeur, Jan N M; Gooijer, Cees; van der Zwan, Gert

    2007-02-13

    Surface-enhanced resonance Raman scattering (SERRS) from dilute solutions (down to nanomolar concentrations) of human mono-oxygenase CYP2D6 is observed using aqueous dispersions of Ag nanoparticles (hydrosol) coated with self-assembled monolayers (SAMs) of mercaptoalkanoic acids of two different lengths. From a direct comparison with its resonance Raman spectrum in solution, CYP2D6 appears to fully retain its native structure upon adsorption on coated hydrosol through electrostatic interaction, while a structural change in the active site is observed when uncoated citrate-reduced hydrosol is used. Using SERRS on these biocompatible coated hydrosols, the effects of dextromethorphan on the enzyme's active site can be observed, demonstrating that CYP2D6 ability of binding substrates is preserved. Moreover, by tuning the wavelength of the exciting laser away from the main absorption band of the heme, the vibrational bands of the SAM coating are observed and analyzed to see how the presence of the protein affects the SAM structure.

  20. Sequencing CYP2D6 for the detection of poor-metabolizers in post-mortem blood samples with tramadol.

    PubMed

    Fonseca, Suzana; Amorim, António; Costa, Heloísa Afonso; Franco, João; Porto, Maria João; Santos, Jorge Costa; Dias, Mário

    2016-08-01

    Tramadol concentrations and analgesic effect are dependent on the CYP2D6 enzymatic activity. It is well known that some genetic polymorphisms are responsible for the variability in the expression of this enzyme and in the individual drug response. The detection of allelic variants described as non-functional can be useful to explain some circumstances of death in the study of post-mortem cases with tramadol. A Sanger sequencing methodology was developed for the detection of genetic variants that cause absent or reduced CYP2D6 activity, such as *3, *4, *6, *8, *10 and *12 alleles. This methodology, as well as the GC/MS method for the detection and quantification of tramadol and its main metabolites in blood samples was fully validated in accordance with international guidelines. Both methodologies were successfully applied to 100 post-mortem blood samples and the relation between toxicological and genetic results evaluated. Tramadol metabolism, expressed as its metabolites concentration ratio (N-desmethyltramadol/O-desmethyltramadol), has been shown to be correlated with the poor-metabolizer phenotype based on genetic characterization. It was also demonstrated the importance of enzyme inhibitors identification in toxicological analysis. According to our knowledge, this is the first study where a CYP2D6 sequencing methodology is validated and applied to post-mortem samples, in Portugal. The developed methodology allows the data collection of post-mortem cases, which is of primordial importance to enhance the application of these genetic tools to forensic toxicology and pathology.

  1. Effects of capsicine on rat cytochrome P450 isoforms CYP1A2, CYP2C19, and CYP3A4.

    PubMed

    Zhu, Hui-dan; Gu, Ni; Wang, Meng; Kong, Hong-ru; Zhou, Meng-tao

    2015-01-01

    Due to the frequent consumption of capsaicin (CAP) and its current therapeutic application, the correct assessment of this compound is important from a public health standpoint. The purpose of this study was to find out whether CAP affects rat cytochrome P450 (CYP) enzymes (CYP1A2, CYP2C19, and CYP3A4) by using cocktail probe drugs in vivo. A cocktail solution at a dose of 5 mL/kg, which contained phenacetin (15 mg/kg), omeprazole (15 mg/kg), and midazolam (10 mg/kg), was given orally to rats treated for 7 d with oral administration of CAP. Blood samples were collected at a series of time-points and the concentrations of probe drugs in plasma were determined by HPLC-MS. The results showed that treatment with multiple doses of CAP had no significant effect on rat CYP1A2. However, CAP had a significant inhibitory effect on CYP2C19 and an inductive effect on CYP3A4. Therefore, caution is needed when CAP is co-administered with some CYP substrates clinically because of potential drug-CAP interactions.

  2. Multicenter Study of Antibiotic Resistance Profile of H. pylori and Distribution of CYP2C19 Gene Polymorphism in Rural Population of Chongqing, China

    PubMed Central

    Han, Ran; Lu, Hong; Jiang, Ming-Wan; Tan, Ke-Wen; Peng, Zhong; Hu, Jia-Li; Fang, Dian-Chun; Lan, Chun-Hui; Wu, Xiao-Ling

    2016-01-01

    This study was to investigate the antibiotic resistance profile of H. pylori and the distribution of CYP2C19 gene polymorphism in rural population of Chongqing, China. 214 and 111 strains of H. pylori were isolated from rural and urban patients, respectively. 99.53%, 20.09%, and 23.36% of the isolates in rural patients were found to be resistant to metronidazole, clarithromycin, and levofloxacin, while the resistant rate in urban patients was 82.88%, 19.82%, and 24.32%. The multiple antibiotic resistance percentage significantly increased from 28.26% (below 45 years) to 41.80% (above 45 years) in rural patients. Up to 44.39%, 45.79%, and 9.81% of rural patients from whom H. pylori was isolated were found to be extensive metabolizers, intermediate metabolizers, and poor metabolizers. No correlation was observed between antibiotic resistance profile of H. pylori and genetic polymorphism of CYP2C19 among rural population. There was a high prevalence of H. pylori strains resistant to metronidazole, clarithromycin, and levofloxacin in rural patients in Chongqing, China. The choice of therapy in this area should be based on local susceptibility patterns. Amoxicillin, gentamicin, and furazolidone are recommended as the first-line empiric regimen. PMID:27247569

  3. Establishment and application of a real-time loop-mediated isothermal amplification system for the detection of CYP2C19 polymorphisms

    PubMed Central

    Zhang, Chao; Yao, Yao; Zhu, Juan-Li; Zhang, Si-Nong; Zhang, Shan-Shan; Wei, Hua; Hui, Wen-Li; Cui, Ya-Li

    2016-01-01

    Single-nucleotide polymorphisms (SNPs) represent the most widespread type of genetic variation (approximately 90%) in the human genome, and the demand to overcome such variation has received more attention now than ever before. The capacity to rapidly assess SNPs that correlate with disease predisposition, drug efficacy and drug toxicity is a key step for the development of personalized medicine. In this work, a rapid one-step SNP detection method, real-time loop-mediated isothermal amplification (RT-LAMP), was first applied for CYP2C19 polymorphisms testing. The optimized method was established with specifically designed primers for target amplification by real-time detection in approximately 30 min under isothermal conditions. RT-LAMP amplified few copies of template to produce significant amounts of product and quantitatively detected human DNA with compatible specificity and sensitivity. The success in the establishment of this RT-LAMP protocol for CYP2C19 polymorphism testing is significant for the extension of this technique for the detection of other SNPs, which will further facilitate the development of personalized medicine. PMID:27246657

  4. Evaluation of CYP2C19, P2Y12, and ABCB1 polymorphisms and phenotypic response to clopidogrel in healthy Indian adults

    PubMed Central

    Sridharan, Kannan; Kataria, Rachna; Tolani, Drishti; Bendkhale, Shital; Gogtay, Nithya J.; Thatte, Urmila M.

    2016-01-01

    Introduction: CYP2C19 and P2Y12 polymorphisms have been claimed to alter the pharmacodynamic response to clopidogrel. ABCB1 polymorphism has been associated with the efflux of clopidogrel resulting in decreased bioavailability. Due to paucity of data from Indian population, the present study was undertaken to evaluate the association of genetic polymorphisms of CYP2C19, P2Y12, and ABCB1 with inhibition of platelet aggregation (IPA) by clopidogrel. Methods: Healthy adults (n = 90) of either gender were administered single dose of 300 mg clopidogrel. Baseline, 4 h postdose, and day 7 assessment of platelet aggregation and genotype of CYP2C19, P2Y12, and ABCB1 were carried out using standardized laboratory methods. The difference in the maximum platelet aggregation (MPA) between baseline and 4 h postdose was considered as delta-MPA (DMPA), and percentage change of MPA at 4 h from baseline was considered as IPA. Those with an IPA of <30% were considered as poor responders. Inferential statistics was applied to find out significant difference of these parameters between various groups of genetic polymorphisms. Results: Mean (standard deviation [SD]) of MPA (%) at baseline, 4 h postdose, and day 7 were 78 (5), 56 (16), and 71 (8), respectively. Similarly, mean (SD) of DMPA (%) and IPA (%) were 23 (17) and 29 (21), respectively. A total of 54/90 (60%) cases were found to be poor responders to clopidogrel. A wild genotype (*1/*1) of CYP2C19 was observed in 35 (40.2%), 42 (48.3%) had *1/*2, 2 (2.3%) individuals had *1/*3, and 8 (9.2%) had *2/*2 mutant genotypes. Although statistically not significant (P = 0.09), a trend was observed in having decreased inhibition values (both MPA and IPA) as we proceed from wild genotype (*1/*1) to mutant genotypes in the order of *1/*2, *1/*3, and *2/*2. Similarly, in P2Y12, a wild haplotype (H1/H1) was present in 77 (89.5%) and 9 (10.5%) individuals had H1/H2 type. A statistically significant difference in DMPA and IPA was observed with

  5. A Case Report of a Patient Carrying CYP2C9*3/4 Genotype with Extremely Low Warfarin Dose Requirement

    PubMed Central

    Lee, Soo-Youn; Nam, Myung-Hyun; Kim, June Soo

    2007-01-01

    We report a case of intolerance to warfarin dosing due to impaired drug metabolism in a patient with CYP2C9*3/*4. A 73-yr-old woman with atrial fibrilation was taking warfarin. She attained a high prothrombin time international normalized ratio (INR) at the standard doses during the induction of anticoagulation and extremely low dose of warfarin (6.5 mg/week) was finally chosen to reach the target INR. Genotyping for CYP2C9 revealed that this patient had a genotype CYP2C9*3/*4. This is the first Korean compound heterozygote for CYP2C9*3 and *4. This case suggests the clinical usefulness of pharmacogenetic testing for individualized dosage adjustments of warfarin. PMID:17596671

  6. The effect of CYP2C9, VKORC1 genotypes and old age on warfarin pharmacologic sensitivity in korean patients with thromboembolic disease.

    PubMed

    Moon, Hee-Won; Noh, Jaekwang; Yun, Yeo-Min; Kim, Hahn Young; Yun, Ik Jin; Song, Junghan; Kim, Jin Q

    2011-01-01

    The therapeutic dose of warfarin is dependent upon intrinsic patient characteristics that are highly variable. We assessed the effects of CYP2C9, VKORC1 1173 C/T polymorphisms, and old age on warfarin dosing and sensitivity by measuring plasma S-/R-warfarin levels in Korean patients. INR and the plasma S-/R-warfarin concentrations were determined in 58 patients who had the VKORC1 1173C/T CYP2C9 genotypes, were on a long-term anticoagulation regimen with warfarin, and took a daily dose of warfarin. The pharmacokinetic sensitivity of warfarin was significantly higher in the CYP2C9 *1/*3 genotypes than in the CYP2C9 *1/*1 genotypes [ratio of S-warfarin concentration/dose, 0.53 vs. 0.21; p=0.01]. Pharmacodynamic sensitivity in older patients (≥ 75 years) with the CYP2C9 *1/*1 and VKORC1 1173 TT genotypes was significantly higher as compared to younger patients (<75 years) [Ratio of INR/S-warfarin concentration, 4.88 vs. 3.41; p = 0.026]. The CYP2C9*3 allele and old age (≥ 75 years) with the VKORC1 1173 T allele were also associated with increased risk of over-anticoagulation. The increase of over-anticoagulation risk and warfarin sensitivity is related to the CYP2C9*3 allele and old age with the VKORC1 1173 T allele in Korean patients with thromboembolic disease. These findings suggest that a lower initial and maintenance dose should be considered for the patients with CYP2C9 *3 allele and advanced age in this patient population. However, due to the limited number of patients in the study population, our finding needs to be confirmed by a larger, well-controlled study. PMID:22075505

  7. Comparison in the in vitro inhibitory effects of major phytocannabinoids and polycyclic aromatic hydrocarbons contained in marijuana smoke on cytochrome P450 2C9 activity.

    PubMed

    Yamaori, Satoshi; Koeda, Kyoko; Kushihara, Mika; Hada, Yui; Yamamoto, Ikuo; Watanabe, Kazuhito

    2012-01-01

    Inhibitory effects of Δ⁹-tetrahydrocannabinol (Δ⁹-THC), cannabidiol (CBD), and cannabinol (CBN), the three major constituents in marijuana, and polycyclic aromatic hydrocarbons (PAHs) contained in marijuana smoke on catalytic activity of human cytochrome P450 (CYP) 2C9 were investigated. These phytocannabinoids concentration-dependently inhibited S-warfarin 7-hydroxylase and diclofenac 4'-hydroxylase activities of human liver microsomes (HLMs) and recombinant CYP2C9 (rCYP2C9). In contrast, none of the twelve PAHs including benz[a]anthracene and benzo[a]pyrene exerted substantial inhibition (IC₅₀ > 10 µM). The inhibitory potentials of Δ⁹-THC (Ki = 0.937-1.50 µM) and CBN (Ki = 0.882-1.29 µM) were almost equivalent regardless of the enzyme sources used, whereas the inhibitory potency of CBD (Ki > = 0.954-9.88 µM) varied depending on the enzyme sources and substrates used. Δ⁹-THC inhibited both S-warfarin 7-hydroxylase and diclofenac 4'-hydroxylase activities of HLMs and rCYP2C9 in a mixed manner. CBD and CBN competitively inhibited the activities of HLMs and rCYP2C9, with the only notable difference being that CBD and CBN exhibited mixed-type inhibitions against diclofenac 4'-hydroxylation and S-warfarin 7-hydroxylation, respectively, by rCYP2C9. None of Δ⁹-THC, CBD, and CBN exerted metabolism-dependent inhibition. These results indicated that the three major phytocannabinoids but not PAHs contained in marijuana smoke potently inhibited CYP2C9 activity and that these cannabinoids can be characterized as direct inhibitors for CYP2C9.

  8. Mechanistic studies of the cationic binding pocket of CYP2C9 in vitro and in silico: metabolism of nonionizable analogs of tienilic acid.

    PubMed

    Tay, Suzanne; Le, Hoa; Ford, Kevin A; Nelson, Sid D; Khojasteh, S Cyrus; Rademacher, Peter M

    2014-11-01

    Tienilic acid (TA) is selectively oxidized at the C-5 position of the thiophene ring by the human liver enzyme cytochrome P450 2C9 (CYP2C9). This oxidation is mediated by the proximal positioning of the thiophene over the heme iron, which is proposed to be coordinated by an interaction of the TA carboxylic acid to a cationic binding pocket in the enzyme active site. In this study, we investigated how chemical modification of TA influences the bioactivation by CYP2C9. For this investigation, nine analogs of TA were chosen with substitutions on either side of the molecule. We tested three parameters, including CYP2C9 inhibition, metabolic profiling, and in silico docking. Of the 10 compounds tested, only two (TA and a noncarboxyl analog) resulted in competitive and time-dependent inhibition of CYP2C9. Metabolic profiling revealed a trend in which substitution of the carboxylate with nonionizable functional groups resulted in metabolic switching from oxidation of the aromatic ring to dealkylation reactions at the opposite side of the structure. The in silico modeling predicted an opposite binding orientation to that of TA for many analogs, including the 3-thenoyl regio-isomer analog, which contradicts previous models. Together these data show that disrupting interactions with the cationic binding pocket of CYP2C9 will impact the sites of metabolism and inhibition of the enzyme.

  9. In Silico Prediction of Cytochrome P450-Drug Interaction: QSARs for CYP3A4 and CYP2C9

    PubMed Central

    Nembri, Serena; Grisoni, Francesca; Consonni, Viviana; Todeschini, Roberto

    2016-01-01

    Cytochromes P450 (CYP) are the main actors in the oxidation of xenobiotics and play a crucial role in drug safety, persistence, bioactivation, and drug-drug/food-drug interaction. This work aims to develop Quantitative Structure-Activity Relationship (QSAR) models to predict the drug interaction with two of the most important CYP isoforms, namely 2C9 and 3A4. The presented models are calibrated on 9122 drug-like compounds, using three different modelling approaches and two types of molecular description (classical molecular descriptors and binary fingerprints). For each isoform, three classification models are presented, based on a different approach and with different advantages: (1) a very simple and interpretable classification tree; (2) a local (k-Nearest Neighbor) model based classical descriptors and; (3) a model based on a recently proposed local classifier (N-Nearest Neighbor) on binary fingerprints. The salient features of the work are (1) the thorough model validation and the applicability domain assessment; (2) the descriptor interpretation, which highlighted the crucial aspects of P450-drug interaction; and (3) the consensus aggregation of models, which largely increased the prediction accuracy. PMID:27294921

  10. High resolution melting method to detect single nucleotide polymorphism of VKORC1 and CYP2C9.

    PubMed

    Chen, Chunxia; Li, Siyue; Lu, Xiaojun; Tan, Bin; Huang, Chunyan; Qin, Li

    2014-01-01

    Single nucleotide polymorphisms (SNPs) of VKORC (1173T/C, rs9934438) and CYP2C9 (1075A/C, rs1057910) are major contributory factors on the sensitivity of warfarin in Chinese. Analysis of the two genomic loci could help warfarin treatment individual from bleeding or thrombosis events. An assay with the advantages of simplicity, speed, high sensitivity and low cost for genotyping is calling for clinical laboratories. High resolution method (HRM) meets these callings, but no study with large sample tested its performance in genotyping of rs9934438 and rs1057910. In this study, we identified polymorphisms of rs9934438 and rs1057910 in 255 unrelated Chinese heart valve replacement patients of Han ethnic group from West China Hospital. The two genomic loci were genotyped by HRM using LightCycler® 480 High Resolution Melting Master on LightCycler® 480 Real-Time PCR instruments (Roche Diagnostics), and all amplified PCR products were sent for direct DNA sequencing. The genotyping of rs1057910 between HRM and sequencing showed perfect 100% concordance. While the concordance of rs9934438 between HRM and sequencing was 99.2%. Unexpected mutation interfered genotyping results of HRM when genotyping rs9934438. HRM is a valuable technique for genotype detection of rs9934438 and rs1057910 to assess individual sensitivity to warfarin, where DNA sequencing is added inevitably sometimes.

  11. Cytochrome P450 2D6 and 3A4 enzyme inhibition by amine stimulants in dietary supplements.

    PubMed

    Liu, Yitong; Santillo, Michael F

    2016-01-01

    A number of dietary supplements used for weight loss and athletic performance enhancement have been recently shown to contain a variety of stimulants, for which there is a lack of pharmacological and toxicological information. One concern for these emerging compounds is their potential to inhibit metabolic enzymes in the liver such as cytochromes P450 (CYP), which can lead to unexpected interactions among dietary supplements, drugs, and other xenobiotics. In this study, inhibition of human recombinant CYP2D6 and CYP3A4 by 27 amine stimulants associated with dietary supplements and their analogs was evaluated by luminescence assays. The strongest CYP2D6 inhibitors were coclaurine (IC50  = 0.14 ± 0.01 μM) and N-benzylphenethylamine (IC50  = 0.7 ± 0.2 μM), followed by several other relatively strong inhibitors (IC50 , 2-12 μM) including β-methylphenethylamine, N,β-dimethylphenethylamine (phenpromethamine), 1,3-dimethylamylamine (DMAA), N,α-diethylphenethylamine, higenamine (norcoclaurine) and N,N-diethylphenethylamine. Only nine compounds inhibited CYP3A4 by 20-55% at 100 μM. Results of this study illustrate that several amine stimulants associated with dietary supplements inhibit CYP2D6 and CYP3A4 in vitro, and these compounds may participate in adverse drug-dietary supplement interactions in vivo. Copyright © 2015 John Wiley & Sons, Ltd.

  12. New aQTL SNPs for the CYP2D6 Identified by a Novel Mediation Analysis of Genome-Wide SNP Arrays, Gene Expression Arrays, and CYP2D6 Activity

    PubMed Central

    Wang, Zhiping; Boustani, Malaz; Liu, Yunlong; Skaar, Todd; Li, Lang

    2013-01-01

    Background. The genome-wide association studies (GWAS) have been successful during the last few years. A key challenge is that the interpretation of the results is not straightforward, especially for transacting SNPs. Integration of transcriptome data into GWAS may provide clues elucidating the mechanisms by which a genetic variant leads to a disease. Methods. Here, we developed a novel mediation analysis approach to identify new expression quantitative trait loci (eQTL) driving CYP2D6 activity by combining genotype, gene expression, and enzyme activity data. Results. 389,573 and 1,214,416 SNP-transcript-CYP2D6 activity trios are found strongly associated (P < 10−5, FDR = 16.6% and 11.7%) for two different genotype platforms, namely, Affymetrix and Illumina, respectively. The majority of eQTLs are trans-SNPs. A single polymorphism leads to widespread downstream changes in the expression of distant genes by affecting major regulators or transcription factors (TFs), which would be visible as an eQTL hotspot and can lead to large and consistent biological effects. Overlapped eQTL hotspots with the mediators lead to the discovery of 64 TFs. Conclusions. Our mediation analysis is a powerful approach in identifying the trans-QTL-phenotype associations. It improves our understanding of the functional genetic variations for the liver metabolism mechanisms. PMID:24232670

  13. Reactions of ethynyl radicals - Rate constants with CH4, C2H6, and C2D6

    NASA Technical Reports Server (NTRS)

    Laufer, A. H.

    1981-01-01

    An experiment to measure ethynyl radical reactivity with other simple molecules is described. Flash photolysis of CF3C2H, a C2H precursor, was kinetically and spectroscopically analyzed for C2H reactions with CH4, C2H6, and C2D6 and rate constants for the abstraction reaction at room temperature were determined. The experimental apparatus is described, and the acetylene feedstock purification procedures are outlined. Rate constants are provided, and additional examination of the effects of added helium showed no alterations over the pressure range 20-700 torr.

  14. Cytochrome P450 2D6 enzyme neuroprotects against 1-methyl-4-phenylpyridinium toxicity in SH-SY5Y neuronal cells.

    PubMed

    Mann, Amandeep; Tyndale, Rachel F

    2010-04-01

    Cytochrome P450 (CYP) 2D6 is an enzyme that is expressed in liver and brain. It can inactivate neurotoxins such as 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, 1,2,3,4-tetrahydroisoquinoline and beta-carbolines. Genetically slow CYP2D6 metabolizers are at higher risk for developing Parkinson's disease, a risk that increases with exposure to pesticides. The goal of this study was to investigate the neuroprotective role of CYP2D6 in an in-vitro neurotoxicity model. SH-SY5Y human neuroblastoma cells express CYP2D6 as determined by western blotting, immunocytochemistry and enzymatic activity. CYP2D6 metabolized 3-[2-(N,N-diethyl-N-methylammonium)ethyl]-7-methoxy-4-methylcoumarin and the CYP2D6-specific inhibitor quinidine (1 microM) blocked 96 +/- 1% of this metabolism, indicating that CYP2D6 is functional in this cell line. Treatment of cells with CYP2D6 inhibitors (quinidine, propanolol, metoprolol or timolol) at varying concentrations significantly increased the neurotoxicity caused by 1-methyl-4-phenylpyridinium (MPP+) at 10 and 25 microM by between 9 +/- 1 and 22 +/- 5% (P < 0.01). We found that CYP3A is also expressed in SH-SY5Y cells and inhibiting CYP3A with ketoconazole significantly increased the cell death caused by 10 and 25 microM of MPP+ by between 8 +/- 1 and 30 +/- 3% (P < 0.001). Inhibiting both CYP2D6 and CYP3A showed an additive effect on MPP+ neurotoxicity. These data further support a possible role for CYP2D6 in neuroprotection from Parkinson's disease-causing neurotoxins, especially in the human brain where expression of CYP2D6 is high in some regions (e.g. substantia nigra). PMID:20345925

  15. Esomeprazole- or rabeprazole-based triple therapy eradicated Helicobacter pylori comparably regardless of clarithromycin susceptibility and CYP2C19 genotypes

    PubMed Central

    Okimoto, Tadayoshi; Mizukami, Kazuhiro; Ogawa, Ryo; Okamoto, Kazuhisa; Shuto, Mitsutaka; Fukuda, Kensuke; Kodama, Masaaki; Murakami, Kazunari

    2016-01-01

    The aim of this study was to assess the efficacy of esomeprazole-based triple therapy compared with rabeprazole-based triple therapy according to CYP2C19 genotype and clarithromycin susceptibility status for first-line eradication therapy of Helicobacter pylori (H. pylori) in Japan. We enrolled 219 H. pylori-infected patients, and randomly allocated patients to the EAC group (esomeprazole 20 mg, clarithromycin 200 mg, amoxicillin 750 mg for one week, with all drugs given twice daily) or RAC group (rabeprazole 10 mg, clarithromycin 200 mg, amoxicillin 750 mg for one week, with all drugs given twice daily). The H. pylori eradication rate according to the PP analyses was 75.0% (95% CI: 65.2–82.8%) in the EAC group and 71.4% (95% CI: 61.4–79.1%) in the RAC group. There were no statistically significant differences. The eradication rates of the clarithromycin-resistant/-sensitive strains were, respectively, 45.0% (95% CI: 30.7–60.2%)/98.0% (95% CI: 88.7–100%) in the EAC group and 39.5% (95% CI: 25.6–55.3%)/93.5% (95% CI: 81.9–98.4%) in the RAC group. The eradication rate of the clarithromycin-sensitive strains was significantly higher than that of the resistant strains in both groups. In conclusion, EAC and RAC therapies show a comparable efficacy regardless of the CYP2C19 genotype and clarithromycin susceptibility status in Japan.

  16. Interethnic differences in the relevance of CYP2C9 genotype and environmental factors for diclofenac metabolism in Hispanics from Cuba and Spain.

    PubMed

    Llerena, A; Alvarez, M; Dorado, P; González, I; Peñas-LLedó, E; Pérez, B; Cobaleda, J; Calzadilla, L R

    2014-06-01

    The aims of this study were to evaluate the diclofenac metabolism in Hispanics from Cuba and Spain and its relation to ethnicity, CYP2C9 genotypes and environmental factors. Diclofenac hydroxylation capacity (concentration ratios of diclofenac/metabolites in 8-h urine) was studied in 160 Cuban (classified as 76 Cuban-Whites-CWs and 84 Cuban-Mestizos-CMs) and 148 Spaniard (SPs) healthy volunteers. Diclofenac and its main metabolites, 4'-hydroxy (OH), 3'-OH and 5-OH diclofenac, and CYP2C9*2 to *6 and *8 alleles were also determined in 132 and 128 CWs and CMs, respectively. Gender, tobacco, caffeine and ethanol consumption were also evaluated. The mean diclofenac/4'-OH diclofenac ratio was higher in CMs (0.72±0.25) than in CWs (0.64±0.20; P<0.05) and SPs (0.57±0.26; P<0.001). The mean diclofenac/4'-OH diclofenac ratio was higher (P<0.05) in subjects with CYP2C9*1/*3 (0.77±0.19; n=22) and CYP2C9*1/*8 (0.93±0.33; n=4) genotypes than with CYP2C9*1/*1 (0.65±0.24; n=90). Environmental factors did not seem to influence the diclofenac metabolism in these populations. The present findings show for the first time interethnic differences between Hispanic groups in urinary diclofenac/4'-OH diclofenac ratios, and the relevance of CYP2C9*3 and CYP2C9*8 alleles.

  17. Metabolism of 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine by Mitochondrion-targeted Cytochrome P450 2D6

    PubMed Central

    Bajpai, Prachi; Sangar, Michelle C.; Singh, Shilpee; Tang, Weigang; Bansal, Seema; Chowdhury, Goutam; Cheng, Qian; Fang, Ji-Kang; Martin, Martha V.; Guengerich, F. Peter; Avadhani, Narayan G.

    2013-01-01

    1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a neurotoxic side product formed in the chemical synthesis of desmethylprodine opioid analgesic, which induces Parkinson disease. Monoamine oxidase B, present in the mitochondrial outer membrane of glial cells, catalyzes the oxidation of MPTP to the toxic 1-methyl-4-phenylpyridinium ion (MPP+), which then targets the dopaminergic neurons causing neuronal death. Here, we demonstrate that mitochondrion-targeted human cytochrome P450 2D6 (CYP2D6), supported by mitochondrial adrenodoxin and adrenodoxin reductase, can efficiently catalyze the metabolism of MPTP to MPP+, as shown with purified enzymes and also in cells expressing mitochondrial CYP2D6. Neuro-2A cells stably expressing predominantly mitochondrion-targeted CYP2D6 were more sensitive to MPTP-mediated mitochondrial respiratory dysfunction and complex I inhibition than cells expressing predominantly endoplasmic reticulum-targeted CYP2D6. Mitochondrial CYP2D6 expressing Neuro-2A cells produced higher levels of reactive oxygen species and showed abnormal mitochondrial structures. MPTP treatment also induced mitochondrial translocation of an autophagic marker, Parkin, and a mitochondrial fission marker, Drp1, in differentiated neurons expressing mitochondrial CYP2D6. MPTP-mediated toxicity in primary dopaminergic neurons was attenuated by CYP2D6 inhibitor, quinidine, and also partly by monoamine oxidase B inhibitors deprenyl and pargyline. These studies show for the first time that dopaminergic neurons expressing mitochondrial CYP2D6 are fully capable of activating the pro-neurotoxin MPTP and inducing neuronal damage, which is effectively prevented by the CYP2D6 inhibitor quinidine. PMID:23258538

  18. Clinical application of a new warfarin-dosing regimen based on the CYP2C9 and VKORC1 genotypes in atrial fibrillation patients

    PubMed Central

    JIANG, NIAN-XIN; GE, JUN-WEI; XIAN, YU-QIONG; HUANG, SHAO-YING; LI, YAN-SONG

    2016-01-01

    The polymorphisms of cytochrome P450 2C9 (CYP2C9) and vitamin K epoxide reductase complex 1 (VKORC1) are important genetic factors for warfarin dose determinations. The present study aimed to investigate the contribution of the CYP2C9 and VKORC1 genotypes to warfarin dose requirement in atrial fibrillation (AF) patients, and to evaluate the clinical application of a warfarin-dosing algorithm. A total of 122 AF patients with a target international normalized ratio of 2.0 to 3.0 were included to determine the genotypes of CYP2C9 (rs1057910) and VKORC1 (rs9923231). A warfarin-dosing algorithm was developed based on age, height, and the CYP2C9 and VKORC1 genotypes of AF patients. The results indicated that the mean warfarin daily dose requirement was lower in the CYP2C9*1/*3 genotype compared with those in the homozygous wild-type CYP2C9*1/*1 patients (P<0.05), and was higher in patients with the VKORC1 AG and GG genotypes compared with those with the AA genotype (P<0.05). The multivariate regression model showed that age, height, and the CYP2C9 and VKORC1 genotypes were the best variables for estimating warfarin dose (R2=56.4%). A new warfarin-dosing algorithm was developed and its validity was confirmed in a second cohort of AF patients. During the 50-day follow-up, 63.3% (19/30) of control group patients and 86.7% (26/30) of patients in the experimental group acquired the warfarin maintenance dose. Among all the patients who acquired the warfarin maintenance dose, the mean time elapse from initiation until warfarin maintenance dose was significantly less in the experimental group (25.8±1.7 day) compared to the control group (33.1±1.9 day) (P<0.05). There was significant linear correlation between predicted warfarin maintenance dose and actual dose (r=0.822, P<0.01). In conclusion, a new warfarin-dosing algorithm was developed based on the CYP2C9 and VKORC1 genotypes, and it can shorten the time elapse from initiation until warfarin maintenance dose in AF patients

  19. Metabolic inhibition of meloxicam by specific CYP2C9 inhibitors in Cunninghamella blakesleeana NCIM 687: in silico and in vitro studies.

    PubMed

    Prasad, G Shyam; Srisailam, K; Sashidhar, R B

    2016-01-01

    Specific inhibitors of Cytochrome P4502C9 enzyme (CYP2C9) viz. clopidogrel, fenofibrate fluvoxamine and sertraline at concentration of 50, 100, 150 and 200 µM were employed to investigate the nature of enzyme involved in bioconversion of meloxicam to its main metabolite 5-OH methyl meloxicam by Cunninghamella blakesleeana. Virtual screening for interaction of specific CYP2C9 inhibitors with human CYP2C9 enzyme was performed by molecular docking using Auto dock vina 4.2 version. The in silico studies were further substantiated by in vitro studies, which indicated fenofibrate to be a potent inhibitor of CYP2C9 enzyme followed by sertraline, clopidogrel and fluvoxamine, respectively. Two-stage fermentation protocol was followed to study metabolism of meloxicam and its inhibition by different CYP2C9 inhibitors. Meloxicam metabolites were identified using HPLC, LC-MS analysis and based on previous reports, as 5-OH methyl meloxicam (M1), 5-carboxy meloxicam (M2) and an unidentified metabolite (M3). All the inhibitors tested in the study showed a clear concentration dependent inhibition of meloxicam metabolism. The results suggest that the enzymes involved in metabolism of meloxicam in C. blakesleeana are akin to mammalian metabolism. Hence, C. blakesleeana can be used as a model organism in studying drug interactions and also in predicting mammalian drug metabolism. PMID:27026863

  20. In vitro and in vivo assessment of CYP2C9-mediated herb–herb interaction of Euphorbiae Pekinensis Radix and Glycyrrhizae Radix

    PubMed Central

    Wang, Xinmin; Peng, Yunru; Jing, Xinyue; Qian, Dawei; Tang, Yuping; Duan, Jin-ao

    2014-01-01

    According to traditional Chinese medicine theories, Euphorbiae Pekinensis Radix and Glycyrrhizae Radix should not be used together in one prescription, because their interaction leads to an unexpected consequence. However, the mechanism remains unclear. The purpose of this study was to find out whether CYP2C9 was involved in this herb–herb interaction by using tolbutamide as a probe substrate in vivo and in vitro. Both Euphorbiae Pekinensis Radix and Glycyrrhizae Radix showed induction activity toward CYP2C9, while the combination of them showed a more potent induction activity toward CYP2C9 in vivo. In vitro study revealed only the combination of the herbs could induce the activity of CYP2C9. Thus, both in vivo and in vitro study indicated combination of Glycyrrhizae Radix and Euphorbiae Pekinensis Radix could induce the activity of CYP2C9 to a high level, which may result in decreased plasma levels of major active ingredients of these two herbs, as well as other herbs in the prescriptions. Further research also appears to be necessary to identify the main enzymes involved in the metabolism of the active ingredients in Glycyrrhizae Radix and Euphorbiae Pekinensis Radix. PMID:25202272

  1. Mutation frequencies of the cytochrome CYP2D6 gene in Parkinson disease patients and in families

    SciTech Connect

    Lucotte, G.; Turpin, J.C.; Gerard, N.

    1996-07-26

    The frequencies of five mutations of the debrisoquine 4-hydroxylase (CYP2D6) gene (mutations D6-A, B, C, D, and T), corresponding to poor metabolizer (PM) phenotypes, were determined by restriction fragment length polymorphism (RFLP) and polymerase chain reaction (PCR) in 47 patients with Parkinson disease, and compared with the findings in 47 healthy controls. These mutant alleles were about twice as frequent among patients as in controls, with an approximate relative risk ratio of 2.12 (95% confidence interval, 1.41-2.62). There seem to be no significant differences in frequencies of mutant genotypes in patients among gender and modalities of response with levodopa therapy; but frequency of the mutations was slightly enhanced after age-at-onset of 60 years. Mutations D6-B, D, and T were detected in 7 patients belonging to 10 Parkinson pedigrees. 25 refs., 1 fig., 2 tabs.

  2. CYP2C9 genotype vs. metabolic phenotype for individual drug dosing--a correlation analysis using flurbiprofen as probe drug.

    PubMed

    Vogl, Silvia; Lutz, Roman W; Schönfelder, Gilbert; Lutz, Werner K

    2015-01-01

    Currently, genotyping of patients for polymorphic enzymes responsible for metabolic elimination is considered a possibility to adjust drug dose levels. For a patient to profit from this procedure, the interindividual differences in drug metabolism within one genotype should be smaller than those between different genotypes. We studied a large cohort of healthy young adults (283 subjects), correlating their CYP2C9 genotype to a simple phenotyping metric, using flurbiprofen as probe drug. Genotyping was conducted for CYP2C9*1, *2, *3. The urinary metabolic ratio MR (concentration of CYP2C9-dependent metabolite divided by concentration of flurbiprofen) determined two hours after flurbiprofen (8.75 mg) administration served as phenotyping metric. Linear statistical models correlating genotype and phenotype provided highly significant allele-specific MR estimates of 0.596 for the wild type allele CYP2C9*1, 0.405 for CYP2C9*2 (68 % of wild type), and 0.113 for CYP2C9*3 (19 % of wild type). If these estimates were used for flurbiprofen dose adjustment, taking 100 % for genotype *1/*1, an average reduction to 84 %, 60 %, 68 %, 43 %, and 19 % would result for genotype *1/*2, *1/*3, *2/*2, *2/*3, and *3/*3, respectively. Due to the large individual variation within genotypes with coefficients of variation ≥ 20 % and supposing the normal distribution, one in three individuals would be out of the average optimum dose by more than 20 %, one in 20 would be 40 % off. Whether this problem also applies to other CYPs and other drugs has to be investigated case by case. Our data for the given example, however, puts the benefit of individual drug dosing to question, if it is exclusively based on genotype.

  3. CYP2C9 Genotype vs. Metabolic Phenotype for Individual Drug Dosing—A Correlation Analysis Using Flurbiprofen as Probe Drug

    PubMed Central

    Vogl, Silvia; Lutz, Roman W.; Schönfelder, Gilbert; Lutz, Werner K.

    2015-01-01

    Currently, genotyping of patients for polymorphic enzymes responsible for metabolic elimination is considered a possibility to adjust drug dose levels. For a patient to profit from this procedure, the interindividual differences in drug metabolism within one genotype should be smaller than those between different genotypes. We studied a large cohort of healthy young adults (283 subjects), correlating their CYP2C9 genotype to a simple phenotyping metric, using flurbiprofen as probe drug. Genotyping was conducted for CYP2C9*1, *2, *3. The urinary metabolic ratio MR (concentration of CYP2C9-dependent metabolite divided by concentration of flurbiprofen) determined two hours after flurbiprofen (8.75 mg) administration served as phenotyping metric. Linear statistical models correlating genotype and phenotype provided highly significant allele-specific MR estimates of 0.596 for the wild type allele CYP2C9*1, 0.405 for CYP2C9*2 (68 % of wild type), and 0.113 for CYP2C9*3 (19 % of wild type). If these estimates were used for flurbiprofen dose adjustment, taking 100 % for genotype *1/*1, an average reduction to 84 %, 60 %, 68 %, 43 %, and 19 % would result for genotype *1/*2, *1/*3, *2/*2, *2/*3, and *3/*3, respectively. Due to the large individual variation within genotypes with coefficients of variation ≥ 20 % and supposing the normal distribution, one in three individuals would be out of the average optimum dose by more than 20 %, one in 20 would be 40 % off. Whether this problem also applies to other CYPs and other drugs has to be investigated case by case. Our data for the given example, however, puts the benefit of individual drug dosing to question, if it is exclusively based on genotype. PMID:25775139

  4. Altered CYP2C9 Activity Following Modulation of CYP3A4 Levels in Human Hepatocytes: an Example of Protein-Protein Interactions

    PubMed Central

    Tweedie, Donald J.; Chan, Tom S.; Tracy, Timothy S.

    2014-01-01

    Cytochrome P450 (P450) protein-protein interactions resulting in modulation of enzyme activities have been well documented using recombinant isoforms. This interaction has been less clearly demonstrated in a more physiologic in vitro system such as human hepatocytes. As an expansion of earlier work (Subramanian et al., 2010), in which recombinant CYP2C9 activity decreased with increasing levels of CYP3A4, the current study modulated CYP3A4 content in human hepatocytes to determine the impact on CYP2C9. Modulation of CYP3A4 levels in situ was enabled by the use of a long-term human hepatocyte culture model (HepatoPac) shown to retain phenotypic hepatocyte function over a number of weeks. The extended period of culture allowed time for knockdown of CYP3A4 protein by small interfering RNA (siRNA) with subsequent recovery, as well as upregulation through induction with a recovery period. CYP3A4 gene silencing resulted in a 60% decrease in CYP3A4 activity and protein levels with a concomitant 74% increase in CYP2C9 activity, with no change in CYP2C9 mRNA levels. Upon removal of siRNA, both CYP2C9 and CYP3A4 activities returned to pre-knockdown levels. Importantly, modulation of CYP3A4 protein levels had no impact on cytochrome P450 reductase activities or levels. However, the possibility for competition for limiting reductase cannot be ruled out. Interestingly, lowering CYP3A4 levels also increased UDP-glucuronosyltransferase 2B7 activity. These studies clearly demonstrate that alterations in CYP3A4 levels can modulate CYP2C9 activity in situ and suggest that further studies are warranted to evaluate the possible clinical consequences of these findings. PMID:25157098

  5. CYP2C9 and VKORC1 Genotypes in Puerto Ricans: A Case for Admixture-Matching in Clinical Pharmacogenetic Studies

    PubMed Central

    Villagra, David; Duconge, Jorge; Windemuth, Andreas; Cadilla, Carmen L; Kocherla, Mohan; Gorowski, Krystyna; Bogaard, Kali; Renta, Jessica Y; Cruz, Irelys A; Mirabal, Sara; Seip, Richard L; Ruaño, Gualberto

    2010-01-01

    Backgrounds Admixture is of great relevance to the clinical application of pharmacogenetics and personalized medicine, but unfortunately these studies have been scarce in Puerto Ricans. Besides, allele frequencies for clinically relevant genetic markers in warfarin response (i.e., CYP2C9 and VKORC1) have not yet been fully characterized in this population. Accordingly, this study is aimed at investigating whether a correlation between overall genetic similarity and CYP2C9 and/or VKORC1 genotypes could be established. Methods 98 DNA samples from Puerto Ricans were genotyped for major CYP2C9 and VKORC1 polymorphisms and tested on a physiogenomic (PG)-array to infer population structure and admixture pattern. Results Analysis affirmed that Puerto Ricans are broadly admixed. A genetic distance dendrogram was constructed by clustering those subjects with similar genetic profiles. Individual VKORC1 and CYP2C9 genotypes were visually overlaid atop the three dendrogram sectors. Sector-1, representing Amerindian ancestry, showed higher VKORC1-1639G>A variant frequency than the rest of the population (p=0.051). Although CYP2C9*3 allele frequencies matched the expected HapMap values, admixture may explain deviations from published findings regarding VKORC1-1639G>A and CYP2C9*2 allele frequencies in sector-3. Conclusions Results suggest that the observed inter-individual variations in ancestral contributions have significant implications for the way each Puerto Rican responds to warfarin therapy. Our findings provide valuable evidence on the importance of controlling for admixture in pharmacogenetic studies of Puerto Rican Hispanics. PMID:20488169

  6. Influence of Cytochrome P450, Family 2, Subfamily D, Polypeptide 6 (CYP2D6) polymorphisms on pain sensitivity and clinical response to weak opioid analgesics.

    PubMed

    Zahari, Zalina; Ismail, Rusli

    2014-01-01

      CYP2D6 polymorphisms show large geographical and interethnic differences. Variations in CYP2D6 activity may impact upon a patient's pain level and may contribute to interindividual variations in the response to opioids. This paper reviews the evidence on how CYP2D6 polymorphisms might influence pain sensitivity and clinical response to codeine and tramadol. For example, it is shown that (1) CYP2D6 poor metabolizers (PMs) may be less efficient at synthesizing endogenous morphine compared with other metabolizers. In contrast, ultra-rapid metabolizers (UMs) may be more efficient than other metabolizers at synthesizing endogenous morphine, thus strengthening endogenous pain modulation. Additionally, for codeine and tramadol that are bioactivated by CYP2D6, PMs may undergo no metabolite formation, leading to inadequate analgesia. Conversely, UMs may experience quicker analgesic effects but be prone to higher mu-opioid-related toxicity. The literature suggested the potential usefulness of the determination of CYP2D6 polymorphisms in elucidating serious adverse events and in preventing subsequent inappropriate selection or doses of codeine and tramadol. Notably, even though many studies investigated a possible role of the CYP2D6 polymorphisms on pain sensitivity, pharmacokinetics and pharmacodynamics of these drugs, the results of analgesia and adverse effects are conflicting. More studies are required to demonstrate genetically determined unresponsiveness and risk of developing serious adverse events for patients with pain and these should involve larger numbers of patients in different population types. PMID:23759977

  7. Influence of Cytochrome P450, Family 2, Subfamily D, Polypeptide 6 (CYP2D6) polymorphisms on pain sensitivity and clinical response to weak opioid analgesics.

    PubMed

    Zahari, Zalina; Ismail, Rusli

    2014-01-01

      CYP2D6 polymorphisms show large geographical and interethnic differences. Variations in CYP2D6 activity may impact upon a patient's pain level and may contribute to interindividual variations in the response to opioids. This paper reviews the evidence on how CYP2D6 polymorphisms might influence pain sensitivity and clinical response to codeine and tramadol. For example, it is shown that (1) CYP2D6 poor metabolizers (PMs) may be less efficient at synthesizing endogenous morphine compared with other metabolizers. In contrast, ultra-rapid metabolizers (UMs) may be more efficient than other metabolizers at synthesizing endogenous morphine, thus strengthening endogenous pain modulation. Additionally, for codeine and tramadol that are bioactivated by CYP2D6, PMs may undergo no metabolite formation, leading to inadequate analgesia. Conversely, UMs may experience quicker analgesic effects but be prone to higher mu-opioid-related toxicity. The literature suggested the potential usefulness of the determination of CYP2D6 polymorphisms in elucidating serious adverse events and in preventing subsequent inappropriate selection or doses of codeine and tramadol. Notably, even though many studies investigated a possible role of the CYP2D6 polymorphisms on pain sensitivity, pharmacokinetics and pharmacodynamics of these drugs, the results of analgesia and adverse effects are conflicting. More studies are required to demonstrate genetically determined unresponsiveness and risk of developing serious adverse events for patients with pain and these should involve larger numbers of patients in different population types.

  8. Prevalence of the CYP2D6*10 (C100T), *4 (G1846A), and *14 (G1758A) alleles among Iranians of different ethnicities.

    PubMed

    Bagheri, Ali; Kamalidehghan, Behnam; Haghshenas, Maryam; Azadfar, Parisa; Akbari, Leila; Sangtarash, Mohammad Hossein; Vejdandoust, Faramarz; Ahmadipour, Fatemeh; Meng, Goh Yong; Houshmand, Massoud

    2015-01-01

    The presence of polymorphisms in the CYP2D6 gene may modulate enzyme level and activity, thereby affecting individual responses to pharmacological treatment. Here, we compared the prevalence of the CYP2D6*10, *4, and 14* alleles in an Iranian population of different ethnicities with those of other populations. Allele and genotype frequency distributions of CYP2D6*10 variants and predicted phenotypes including extensive metabolizers, intermediate metabolizers, and poor metabolizers were analysed in blood samples of 300 unrelated healthy individuals in an Iranian population using polymerase chain reaction (PCR)-restriction fragment length polymorphism, PCR-single-strand conformation polymorphism, and direct genomic DNA sequencing. The CYP2D6*4 (G1846A) and *14 (G1758A) allelic frequencies were not detected in different ethnicities, demonstrating the absence of a significant contribution of these alleles in Iranian populations. However, the T/T, C/T, and C/C genotype frequencies of the CYP2D6*10 allele were significantly different (P<0.01) in all Iranian ethnic groups. Additionally, the frequency of the homozygous T/T variant of the CYP2D6*10 allele was significantly high in the Lure (P<0.017) and low in the Kurd (P<0.002) ethnicities. The frequency of the T/T variant of the CYP2D6*10 allele in central Iran was the highest (P<0.001), while the south of Iran had the lowest frequency (P<0.001). The frequency of the C/T variant of the CYP2D6*10 allele was significantly a bit high (P<0.001) in females compare to males, while the frequencies of the T/T variant in females is similar to males, which are 24.4% and 24.3%, respectively. In contrast to absence of the CYP2D6*4 (G1846A) and *14 (G1758A) alleles in Iranian populations of different ethnicities, the prediction of the CYP2D6*10 allele is required in drug research and routine treatment, where the information would be helpful for clinicians to optimize therapy or identify persons at risk of adverse drug reactions before

  9. Phytoremediation of the herbicides atrazine and metolachlor by transgenic rice plants expressing human CYP1A1, CYP2B6, and CYP2C19.

    PubMed

    Kawahigashi, Hiroyuki; Hirose, Sakiko; Ohkawa, Hideo; Ohkawa, Yasunobu

    2006-04-19

    This study evaluated the expression of human cytochrome P450 genes CYP1A1, CYP2B6, and CYP2C19 in rice plants (Oryza sativa cv. Nipponbare) introduced using the plasmid pIKBACH. The transgenic rice plants (pIKBACH rice plants) became more tolerant toward various herbicides than nontransgenic Nipponbare rice plants. Rice plants expressing pIKBACH grown in soil showed tolerance to the herbicides atrazine, metolachlor, and norflurazon and to a mixture of the three herbicides. The degradation of atrazine and metolachlor by pIKBACH rice plants was evaluated to confirm the metabolic activity of the introduced P450s. Although both pIKBACH and nontransgenic Nipponbare rice plants could decrease the amounts of the herbicides in plant tissue and culture medium, pIKBACH rice plants removed greater amounts in greenhouse experiments. The ability of pIKBACH rice plants to remove atrazine and metolachlor from soil was confirmed in large-scale experiments. The metabolism of herbicides by pIKBACH rice plants was enhanced by the introduced P450 species. Assuming that public and commercial acceptance is forthcoming, pIKBACH rice plants may become useful tools for the breeding of herbicide-tolerant crops and for phytoremediation of environmental pollution by organic chemicals. PMID:16608219

  10. Warfarin Dosing in a Patient with CYP2C9(∗)3(∗)3 and VKORC1-1639 AA Genotypes.

    PubMed

    Johnson, Mark; Richard, Craig; Bogdan, Renee; Kidd, Robert

    2014-01-01

    Genetic factors most correlated with warfarin dose requirements are variations in the genes encoding the enzymes cytochrome P450 2C9 (CYP2C9) and vitamin K epoxide reductase (VKOR). Patients receiving warfarin who possess one or more genetic variations in CYP2C9 and VKORC1 are at increased risk of adverse drug events and require significant dose reductions to achieve a therapeutic international normalized ratio (INR). A 74-year-old white female with atrial fibrillation was initiated on a warfarin dose of 2 mg PO daily, which resulted in multiple elevated INR measurements and three clinically significant hemorrhagic events and four vitamin K antidote treatments over a period of less than two weeks. Genetic analysis later revealed that she had the homozygous variant genotypes of CYP2C9∗3∗3 and VKORC1-1639 AA. Warfarin dosing was subsequently restarted and stabilized at 0.5 mg PO daily with therapeutic INRs. This is the first case report of a white female with these genotypes stabilized on warfarin, and it highlights the value of pharmacogenetic testing prior to the initiation of warfarin therapy to maximize efficacy and minimize the risk of adverse drug events. PMID:24627811

  11. Warfarin Dosing in a Patient with CYP2C9∗3∗3 and VKORC1-1639 AA Genotypes

    PubMed Central

    Bogdan, Renee

    2014-01-01

    Genetic factors most correlated with warfarin dose requirements are variations in the genes encoding the enzymes cytochrome P450 2C9 (CYP2C9) and vitamin K epoxide reductase (VKOR). Patients receiving warfarin who possess one or more genetic variations in CYP2C9 and VKORC1 are at increased risk of adverse drug events and require significant dose reductions to achieve a therapeutic international normalized ratio (INR). A 74-year-old white female with atrial fibrillation was initiated on a warfarin dose of 2 mg PO daily, which resulted in multiple elevated INR measurements and three clinically significant hemorrhagic events and four vitamin K antidote treatments over a period of less than two weeks. Genetic analysis later revealed that she had the homozygous variant genotypes of CYP2C9∗3∗3 and VKORC1-1639 AA. Warfarin dosing was subsequently restarted and stabilized at 0.5 mg PO daily with therapeutic INRs. This is the first case report of a white female with these genotypes stabilized on warfarin, and it highlights the value of pharmacogenetic testing prior to the initiation of warfarin therapy to maximize efficacy and minimize the risk of adverse drug events. PMID:24627811

  12. Oriented Attachment of Cytochrome P450 2C9 to a Self-Assembled Monolayer on a Gold Electrode as a Biosensor Design

    NASA Astrophysics Data System (ADS)

    Schneider, Elizabeth Ann

    Cytochrome P450s (CYPs) are a family of enzymes implicated in the metabolism of drugs in the body. Consequently, P450 reactions are of high interest to the pharmaceutical industry, where lead compounds in drug development are screened as potential substrates of CYPs. The P450 reaction involves electron transfer to an iron heme via NADPH and the electron transfer partner enzyme P450 reductase (CPR). By immobilizing CYPs on an electrode however, NADPH and CPR are potentially no longer needed and the immobilized CYP can act as a biosensor by accepting electrons directly from the electrode. Such a biosensor could be used as an initial screening tool for CYP reactivity of pharmaceuticals in development. In this study, the drug-metabolizing enzyme CYP 2C9 was immobilized to a self-assembled monolayer (SAM) on a gold electrode in three different orientations to investigate the effect that orientation has on the direct electrochemistry of CYP and to evaluate oriented attachment of CYP to an electrode as a biosensor design. Three attachment methods were investigated: random attachment via amine coupling to a carboxy-terminated SAM, oriented attachment via C-terminal His-tag coupling to a Ni-NTA-functionalized SAM, and oriented attachment via maleimide/thiol coupling to a maleimide-functionalized SAM. Three 2C9 mutants (R125C, R132C, and K432C) were developed with a single cysteine mutation at the binding site for CPR on the side of the enzyme closest to the heme; attachment of these mutants to a gold electrode via maleimide/thiol coupling would orient the enzyme such that electron transfer occurs on the electrode in the same orientation that it does in vivo with CPR. Therefore, we expected oriented attachment via maleimide/thiol coupling to produce the most electroactive CYP biosensor. Electrochemical analysis and surface characterization of the SAMs on gold electrodes confirmed that electron transfer occurs through the SAMs, and activity assays of the 2C9 electrodes

  13. Changes in CYP2C19 enzyme activity evaluated by the [(13)C]-pantoprazole breath test after co-administration of clopidogrel and proton pump inhibitors following percutaneous coronary intervention and correlation to platelet reactivity.

    PubMed

    Harvey, Adrien; Modak, Anil; Déry, Ugo; Roy, Mélanie; Rinfret, Stéphane; Bertrand, Olivier F; Larose, Éric; Rodés-Cabau, Josep; Barbeau, Gérald; Gleeton, Onil; Nguyen, Can Manh; Proulx, Guy; Noël, Bernard; Roy, Louis; Paradis, Jean-Michel; De Larochellière, Robert; Déry, Jean-Pierre

    2016-03-01

    Dual antiplatelet therapy (DAPT) with clopidogrel and aspirin is used for the prevention of cardiovascular events following percutaneous coronary intervention (PCI). These agents increase the risk of gastrointestinal bleeding. To prevent these events, proton pump inhibitors (PPI) are routinely prescribed. It has been reported that with the exception of pantoprazole and dexlanzoprazole, PPIs can impede conversion of clopidogrel by cytochrome P450 2C19 (CYP2C19) to its active metabolite, a critical step required for clopidogrel efficacy. Changes in CYP2C19 enzyme activity (phenotype) and its correlation with platelet reactivity following PPI therapy has not yet been fully described. In this study we attempted to determine if the [ (13)C]-pantoprazole breath test (Ptz-BT) can evaluate changes in CYP2C19 enzyme activity (phenoconversion) following the administration of PPI in coronary artery disease (CAD) patients treated with DAPT after PCI. Thirty (30) days after successful PCI with stent placement, 59 patients enrolled in the Evaluation of the Influence of Statins and Proton Pump Inhibitors on Clopidogrel Antiplatelet Effects (SPICE) trial (ClinicalTrials.gov Identifier: NCT00930670) were recruited to participate in this sub study. Patients were randomized to one of 4 antacid therapies (omeprazole, esomeprazole. pantoprazole or ranitidine). Subjects were administered the Ptz-BT and platelet function was evaluated by vasodilator-stimulated phosphoprotein (VASP) phosphorylation and light transmittance aggregometry before and 30 d after treatment with antacid therapy. Patients randomized to esomeprazole and omeprazole had greater high on-treatment platelet reactivity and lowering of CYP2C19 enzyme activity at Day 60 after 30 d of PPI therapy. Patients randomized to ranitidine and pantoprazole did not show any changes in platelet activity or CYP 2C19 enzyme activity. In patients treated with esomeprazole and omeprazole, changes in CYP2C19 enzyme activity

  14. Physiologically Based Pharmacokinetic Predictions of Tramadol Exposure Throughout Pediatric Life: an Analysis of the Different Clearance Contributors with Emphasis on CYP2D6 Maturation.

    PubMed

    T'jollyn, Huybrecht; Snoeys, Jan; Vermeulen, An; Michelet, Robin; Cuyckens, Filip; Mannens, Geert; Van Peer, Achiel; Annaert, Pieter; Allegaert, Karel; Van Bocxlaer, Jan; Boussery, Koen

    2015-11-01

    This paper focuses on the retrospective evaluation of physiologically based pharmacokinetic (PBPK) techniques used to mechanistically predict clearance throughout pediatric life. An intravenous tramadol retrograde PBPK model was set up in Simcyp® using adult clearance values, qualified for CYP2D6, CYP3A4, CYP2B6, and renal contributions. Subsequently, the model was evaluated for mechanistic prediction of total, CYP2D6-related, and renal clearance predictions in very early life. In two in vitro pediatric human liver microsomal (HLM) batches (1 and 3 months), O-desmethyltramadol and N-desmethyltramadol formation rates were compared with CYP2D6 and CYP3A4 activity, respectively. O-desmethyltramadol formation was mediated only by CYP2D6, while N-desmethyltramadol was mediated in part by CYP3A4. Additionally, the clearance maturation of the PBPK model predictions was compared to two in vivo maturation models (Hill and exponential) based on plasma concentration data, and to clearance estimations from a WinNonlin® fit of plasma concentration and urinary excretion data. Maturation of renal and CYP2D6 clearance is captured well in the PBPK model predictions, but total tramadol clearance is underpredicted. The most pronounced underprediction of total and CYP2D6-mediated clearance was observed in the age range of 2-13 years. In conclusion, the PBPK technique showed to be a powerful mechanistic tool capable of predicting maturation of CYP2D6 and renal tramadol clearance in early infancy, although some underprediction occurs between 2 and 13 years for total and CYP2D6-mediated tramadol clearance. PMID:26209290

  15. Effect of Curcuma longa on CYP2D6- and CYP3A4-mediated metabolism of dextromethorphan in human liver microsomes and healthy human subjects.

    PubMed

    Al-Jenoobi, Fahad Ibrahim; Al-Thukair, Areej A; Alam, Mohd Aftab; Abbas, Fawkeya A; Al-Mohizea, Abdullah M; Alkharfy, Khalid M; Al-Suwayeh, Saleh A

    2015-03-01

    Effect of Curcuma longa rhizome powder and its ethanolic extract on CYP2D6 and CYP3A4 metabolic activity was investigated in vitro using human liver microsomes and clinically in healthy human subjects. Dextromethorphan (DEX) was used as common probe for CYP2D6 and CYP3A4 enzymes. Metabolic activity of CYP2D6 and CYP3A4 was evaluated through in vitro study; where microsomes were incubated with NADPH in presence and absence of Curcuma extract. In clinical study phase-I, six healthy human subjects received a single dose (30 mg) of DEX syrup, and in phase-II DEX syrup was administered with Curcuma powder. The enzyme CYP2D6 and CYP3A4 mediated O- and N-demethylation of dextromethorphan into dextrorphan (DOR) and 3-methoxymorphinan (3-MM), respectively. Curcuma extract significantly inhibited the formation of DOR and 3-MM, in a dose-dependent and linear fashion. The 100 μg/ml dose of curcuma extract produced highest inhibition, which was about 70 % for DOR and 80 % for 3-MM. Curcuma significantly increases the urine metabolic ratio of DEX/DOR but the change in DEX/3-MM ratio was statistically insignificant. Present findings suggested that curcuma significantly inhibits the activity of CYP2D6 in in vitro as well as in vivo; which indicates that curcuma has potential to interact with CYP2D6 substrates.

  16. Systematic and quantitative assessment of the effect of chronic kidney disease on CYP2D6 and CYP3A4/5

    PubMed Central

    Yoshida, K; Sun, B; Zhang, L; Zhao, P; Abernethy, DR; Nolin, TD; Rostami‐Hodjegan, A; Zineh, I

    2016-01-01

    Recent reviews suggest that chronic kidney disease (CKD) can affect the pharmacokinetics of nonrenally eliminated drugs, but the impact of CKD on individual elimination pathways has not been systematically evaluated. In this study we developed a comprehensive dataset of the effect of CKD on the pharmacokinetics of CYP2D6‐ and CYP3A4/5‐metabolized drugs. Drugs for evaluation were selected based on clinical drug–drug interaction (CYP3A4/5 and CYP2D6) and pharmacogenetic (CYP2D6) studies. Information from dedicated CKD studies was available for 13 and 18 of the CYP2D6 and CYP3A4/5 model drugs, respectively. Analysis of these data suggested that CYP2D6‐mediated clearance is generally decreased in parallel with the severity of CKD. There was no apparent relationship between the severity of CKD and CYP3A4/5‐mediated clearance. The observed elimination‐route dependency in CKD effects between CYP2D6 and CYP3A4/5 may inform the need to conduct clinical CKD studies with nonrenally eliminated drugs for optimal use of drugs in patients with CKD. PMID:26800425

  17. The relationship between trauma and personality in victims of the Boeing 737-2D6C crash in Coventry.

    PubMed

    Chung, M C; Easthope, Y; Chung, C; Clark-Carter, D

    1999-05-01

    The aims of this paper were to (a) ascertain the extent of psychological distress and (b) identify the association between personality variables and psychological distress among individuals who had been exposed to an aircraft disaster in Coventry, U.K. Hundreds of people escaped death but were exposed to the impact of the disaster when a Boeing 737-2D6C 7T-VEE crashed into a woodland area on the edge of a large housing estate in Coventry, U.K. in 1994. Eighty-two residents were randomly chosen for interviews in which they were assessed using the Impact of Event Scale, the General Health Questionnaire, and the Eysenck Personality Questionnaire-R Short Scale (EPQ-R). The results showed that the Coventry residents' scores reached similar levels of intrusion and avoidance compared with standardized samples and the Lockerbie samples. Fifty-two percent reached the GHQ case level score, which was again similar to the Lockerbie residents. The Coventry residents were significantly less extroverted and neurotic than standardized samples. Stepwise multiple regression showed that there were associations between intrusion and neuroticism and intrusion and extroversion, as well as between avoidance and neuroticism.

  18. Systematic Functional Study of Cytochrome P450 2D6 Promoter Polymorphisms in the Chinese Han Population

    PubMed Central

    Gong, Xueli; Liu, Yichen; Zhang, Xiaoqing; Wei, Zhiyun; Huo, Ran; Shen, Lu; He, Lin; Qin, Shengying

    2013-01-01

    The promoter polymorphisms of drug-metabolizing genes can lead to interindividual differences in gene expression, which may result in adverse drug effects and therapeutic failure. Based on the database of CYP2D6 gene polymorphisms in the Chinese Han population established by our group, we functionally characterized the single nucleotide polymorphisms (SNPs) of the promoter region and corresponding haplotypes in this population. Using site-directed mutagenesis, all the five SNPs identified and ten haplotypes with a frequency equal to or greater than 0.01 in the population were constructed on a luciferase reporter system. Dual luciferase reporter systems were used to analyze regulatory activity. The activity produced by Haplo3(−2183G>A, −1775A>G, −1589G>C, −1431C>T, −1000G>A, −678A>G), Haplo8(−2065G>A, −2058T>G, −1775A>G, −1589G>C, −1235G>A, −678A>G) and MU3(−498C>A) was 0.7−, 0.7−, 1.2− times respectively compared with the wild type in human hepatoma cell lines(p<0.05). These findings might be useful for optimizing pharmacotherapy and the design of personalized medicine. PMID:23469064

  19. An allele-specific PCR system for rapid detection and discrimination of the CYP2C19∗4A, ∗4B, and ∗17 alleles: implications for clopidogrel response testing.

    PubMed

    Scott, Stuart A; Tan, Qian; Baber, Usman; Yang, Yao; Martis, Suparna; Bander, Jeffrey; Kornreich, Ruth; Hulot, Jean-Sébastien; Desnick, Robert J

    2013-11-01

    CYP2C19 is involved in the metabolism of clinically relevant drugs, including the antiplatelet prodrug clopidogrel, which has prompted interest in clinical CYP2C19 genotyping. The CYP2C19∗4B allele is defined by both gain-of-function [c.-806C>T (∗17)] and loss-of-function [c.1A>G (∗4)] variants on the same haplotype; however, current genotyping and sequencing assays are unable to determine the phase of these variants. Thus, the aim of this study was to develop an assay that could rapidly detect and discriminate the related ∗4A, ∗4B, and ∗17 alleles. An allele-specific PCR assay, composed of four unique primer mixes that specifically interrogate the defining ∗17 and ∗4 variants, was developed by using samples (n = 20) with known genotypes, including the ∗4A, ∗4B, and/or ∗17 alleles. The assay was validated by testing 135 blinded samples, and the results were correlated with CYP2C19 genotyping and allele-specific cloning/sequencing. Importantly, among the six ∗4 carriers in the validation cohort, after allele-specific PCR testing both samples with a ∗1/∗4 genotype were reclassified to ∗1/∗4A, all three samples with a ∗4/∗17 genotype were reclassified to ∗1/∗4B, and a sample with a ∗4/∗17/∗17 genotype was reclassified to ∗4B/∗17. In conclusion, this rapid and robust allele-specific PCR assay can refine CYP2C19 genotyping and metabolizer phenotype classification by determining the phase of the defining ∗17 and ∗4 variants, which may have utility when testing CYP2C19 for clopidogrel response.

  20. Roles of phenylalanine at position 120 and glutamic acid at position 222 in the oxidation of chiral substrates by cytochrome P450 2D6.

    PubMed

    Masuda, Kazufumi; Tamagake, Keietsu; Katsu, Takashi; Torigoe, Fumihiro; Saito, Keita; Hanioka, Nobumitsu; Yamano, Shigeru; Yamamoto, Shigeo; Narimatsu, Shizuo

    2006-02-01

    The roles of Phe-120 and Glu-222 in the oxidation of chiral substrates bunitrolol (BTL) and bufuralol (BF) by CYP2D6 are discussed. Wild-type CYP2D6 (CYP2D6-WT) oxidized BTL to 4-hydroxybunitrolol (4-OH-BTL) with substrate enantioselectivity of (R)-(+)-BTL > (S)-(-)-BTL. The same enzyme converted BF into 1''-hydroxybufuralol with substrate enantioselectivity of (R)-BF > (S)-BF and metabolite diastereoselectivity of (1''R)-OH < (1''S)-OH. The substitution of Phe-120 by alanine markedly increased the apparent K(m) and V(max) values for enantiomeric BTL 4-hydroxylation by CYP2D6. In contrast, the same substitution caused an increase only in V(max) values of (S)-BF 1''-hydroxylation without changing apparent K(m) values, while kinetic parameters (K(m) and V(max) values) for (R)-BF 1''-hydroxylation remained unchanged. Furthermore, the substitution of Glu-222 as well as Glu-216 by alanine remarkably decreased both the apparent K(m) and V(max) values without changing substrate enantioselectivity or metabolite diastereoselectivity. A computer-assisted simulation study using energy minimization and molecular dynamics techniques indicated that the hydrophobic interaction of an aromatic moiety of the substrate with Phe-120 and the ionic interaction of a basic nitrogen atom of the substrate with Glu-222 in combination with Glu-216 play important roles in the binding of BF and BTL by CYP2D6 and the orientation of these substrates in the active-site cavity. This modeling yielded a convincing explanation for the reversal of substrate enantioselectivity in BTL 4-hydroxylation between CYP2D6-WT and CYP2D6-V374M having methionine in place of Val-374, which supports the validity of this modeling.

  1. Pharmacokinetic interactions between monoamine oxidase A inhibitor harmaline and 5-methoxy-N,N-dimethyltryptamine, and the impact of CYP2D6 status.

    PubMed

    Jiang, Xi-Ling; Shen, Hong-Wu; Mager, Donald E; Yu, Ai-Ming

    2013-05-01

    5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT or street name "5-MEO") is a newer designer drug belonging to a group of naturally occurring indolealkylamines. Our recent study has demonstrated that coadministration of monoamine oxidase A (MAO-A) inhibitor harmaline (5 mg/kg) increases systemic exposure to 5-MeO-DMT (2 mg/kg) and active metabolite bufotenine. This study is aimed at delineating harmaline and 5-MeO-DMT pharmacokinetic (PK) interactions at multiple dose levels, as well as the impact of CYP2D6 that affects harmaline PK and determines 5-MeO-DMT O-demethylation to produce bufotenine. Our data revealed that inhibition of MAO-A-mediated metabolic elimination by harmaline (2, 5, and 15 mg/kg) led to a sharp increase in systemic and cerebral exposure to 5-MeO-DMT (2 and 10 mg/kg) at all dose combinations. A more pronounced effect on 5-MeO-DMT PK was associated with greater exposure to harmaline in wild-type mice than CYP2D6-humanized (Tg-CYP2D6) mice. Harmaline (5 mg/kg) also increased blood and brain bufotenine concentrations that were generally higher in Tg-CYP2D6 mice. Surprisingly, greater harmaline dose (15 mg/kg) reduced bufotenine levels. The in vivo inhibitory effect of harmaline on CYP2D6-catalyzed bufotenine formation was confirmed by in vitro study using purified CYP2D6. Given these findings, a unified PK model including the inhibition of MAO-A- and CYP2D6-catalyzed 5-MeO-DMT metabolism by harmaline was developed to describe blood harmaline, 5-MeO-DMT, and bufotenine PK profiles in both wild-type and Tg-CYP2D6 mouse models. This PK model may be further employed to predict harmaline and 5-MeO-DMT PK interactions at various doses, define the impact of CYP2D6 status, and drive harmaline-5-MeO-DMT pharmacodynamics.

  2. CYP2D6 function moderates the pharmacokinetics and pharmacodynamics of 3,4-methylene-dioxymethamphetamine in a controlled study in healthy individuals.

    PubMed

    Schmid, Yasmin; Vizeli, Patrick; Hysek, Cédric M; Prestin, Katharina; Meyer Zu Schwabedissen, Henriette E; Liechti, Matthias E

    2016-08-01

    The role of genetic polymorphisms in cytochrome (CYP) 2D6 involved in the metabolism of 3,4-methylene-dioxymethamphetamine (MDMA, ecstasy) is unclear. Effects of genetic variants in CYP2D6 on the pharmacokinetics and pharmacodynamic effects of MDMA were characterized in 139 healthy individuals (70 men, 69 women) in a pooled analysis of eight double-blind, placebo-controlled crossover studies. In CYP2D6 poor metabolizers, the maximum concentrations (Cmax) of MDMA and its active metabolite 3,4-methylene-dioxyamphetamine were +15 and +50% higher, respectively, compared with extensive metabolizers and the Cmax of the inactive metabolite 4-hydroxy-3-methoxymethamphetamine was 50-70% lower. Blood pressure and subjective drug effects increased more rapidly after MDMA administration in poor metabolizers than in extensive metabolizers. In conclusion, the disposition of MDMA and its effects in humans are altered by polymorphic CYP2D6 activity, but the effects are small because of the autoinhibition of CYP2D6. PMID:27253829

  3. CYP2D6 function moderates the pharmacokinetics and pharmacodynamics of 3,4-methylene-dioxymethamphetamine in a controlled study in healthy individuals

    PubMed Central

    Schmid, Yasmin; Vizeli, Patrick; Hysek, Cédric M.; Prestin, Katharina; Meyer zu Schwabedissen, Henriette E.

    2016-01-01

    The role of genetic polymorphisms in cytochrome (CYP) 2D6 involved in the metabolism of 3,4-methylene-dioxymethamphetamine (MDMA, ecstasy) is unclear. Effects of genetic variants in CYP2D6 on the pharmacokinetics and pharmacodynamic effects of MDMA were characterized in 139 healthy individuals (70 men, 69 women) in a pooled analysis of eight double-blind, placebo-controlled crossover studies. In CYP2D6 poor metabolizers, the maximum concentrations (Cmax) of MDMA and its active metabolite 3,4-methylene-dioxyamphetamine were +15 and +50% higher, respectively, compared with extensive metabolizers and the Cmax of the inactive metabolite 4-hydroxy-3-methoxymethamphetamine was 50–70% lower. Blood pressure and subjective drug effects increased more rapidly after MDMA administration in poor metabolizers than in extensive metabolizers. In conclusion, the disposition of MDMA and its effects in humans are altered by polymorphic CYP2D6 activity, but the effects are small because of the autoinhibition of CYP2D6. PMID:27253829

  4. [The possibility of selecting optimal antiplatelet therapy in patients with coronary heart disease in terms of CYP2C19 polymorphism].

    PubMed

    Bokeriya, O L; Kudzoeva, Z F; Shvarts, V A; Koasari, A K; Donakanyan, S A

    2016-01-01

    Резюме Цель исследования. Оценить возможность подбора оптимальной антиагрегантной терапии с учетом полиморфизма CYP2C19. Материалы и методы. В проспективное рандомизированное исследование включили 124 пациентов (93 мужчин и 31 женщина), которым планировалось выполнение чрескожного коронарного вмешательства (ЧКВ). Исходно они получали двухкомпонентную антиагрегантную терапию: 75 мг клопидогрела + 300 мг ацетилсалициловой кислоты (АСК). Всем проводили генетическое исследование для выявления носительства аллельных вариантов генов изоферментов цитохрома Р-450 и оценку эффективности антиагрегантной терапии. Носители одного аллеля (CYP2C19*2/*1) случайным образом разделили на 3 подгруппы в зависимости от дальнейшей антитромбоцитарной медикаментозной терапии. В 1-й подгруппе терапию не изменяли, во 2-й подгруппе увеличили дозу клопидогрела до 150 мг/сут, АСК сохранили в той же дозе, в 3-й подгруппе изменили терапию полностью на схему: АСК 300 мг + тикагрелор 90 мг 2 раза в сутки. Через 3 сут во всех 3 подгруппах выполнено повторное исследование агрегации тромбоцитов. Результаты. Распространенность

  5. Impact of Cytochrome P450 2C19* 2 and * 3 on Clopidogrel Loading Dose in Saudi Patients with Acute Coronary Syndrome

    PubMed Central

    Khalaf, Hassan; AlMeman, Ahmad AbdulRahman; Rasool, Seemab

    2016-01-01

    Background: Emerging evidence shows that clopidogrel is greatly affected by non-functioning alleles measured by P2Y12 or platelet reactivity units (PRU). Cardiac events during short in-hospital stays have been inconclusively suggested as the main causes of discrepancies. Objectives: Evaluate the impact of CYP2C19 allele * 2 and allele * 3 on PRU and the potential clinical consequences of such interaction. To establish a rough estimation for the safe PRU limits for short in-hospital stay following PCI. Method: A short-term experimental study was conducted with 90 patients who underwent coronary angioplasty with drug eluting stents at the Prince Sultan Cardiac Center, Buraidah. All the patients received an initial loading dose of 300 mg clopidogrel, followed by 75 mg daily. Blood samples were used for DNA extraction for cytochrome P450 (CYP) and real-time polymerase chain reaction (PCR) was used for genotyping. PRU and inhibition rate were tested by Verifynow®. All in-hospital cardiac events were recorded until patients were discharged. Results: Genotypes 1/1, 2/2, and 1/2 were expressed by 60, 28, and two patients (67, 32, and 3%), respectively. The 
PRU of the female patients was significantly higher than that of the male patients was (255.6 ± 68.8 and 177.7 ± 66.6, 
p = 0.000, respectively). There was no significant difference in PRUs (193 ± 79 and 212 ±55.4, respectively, p = 0.349), nor inhibition (17.9 ± 18.80 and 13.88 ± 11.5, p = 0.135) in wild and resistant variants, respectively. We only reported one cardiac in-thrombosis events. Conclusion: Genotype differences may not explain variations in the PRU of patients during short-term in-hospital stays. Although it is difficult to confirm, 117–267 units may be a safe PRU range for such patients, with emphasis on attaining higher PRU values in females.

  6. Cost-Effectiveness of Cytochrome P450 2C19 Genotype Screening for Selection of Antiplatelet Therapy with Clopidogrel or Prasugrel

    PubMed Central

    Reese, Emily S.; Mullins, C. Daniel; Beitelshees, Amber L.; Onukwugha, Eberechukwu

    2013-01-01

    Study Objective To estimate the cost-effectiveness of genotype-guided selection of antiplatelet therapy compared with selecting clopidogrel or prasugrel irrespective of genotype. Design Decision model based on event occurrence in the Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition with Prasugrel–Thrombolysis in Myocardial Infarction (TRITON-TIMI) 38. Patients Simulated cohort of patients with acute coronary syndrome scheduled to undergo percutaneous coronary intervention (PCI), consisting of three arms: those receiving genotype-guided antiplatelet therapy with clopidogrel or prasugrel, those receiving clopidogrel regardless of genotype, and those receiving prasugrel regardless of genotype. Measurements and Main Results All three arms of the model incorporated the probability that patients would experience a cardiovascular event (death from cardiovascular causes, nonfatal myocardial infarction, or non-fatal stroke), a bleeding event (major or minor bleeding), or no event while receiving antiplatelet therapy during the 15 months after the scheduled PCI. The cytochrome P450 (CYP) 2C19 genotype determined antiplatelet drug selection in the genotyping group. Cost-effectiveness was expressed as the incremental cost-effectiveness ratio (ICER) for each event avoided in the genotype-guided therapy arm versus the other two arms. Genotype-guided antiplatelet therapy was dominant, or more effective and less costly, when compared with the selection of clopidogrel (ICER –$6760 [95% confidence interval (CI) –$6720 to –$6790]) or prasugrel (ICER –$11,710 [95% CI –$11,480 to –$11,950]) for all patients with-out regard to genotype. Genotype-guided therapy that included generic clopidogrel was dominant to prasugrel for all patients (ICER –$27,160 [95% CI –$27,890 to –$26,420]). Cost savings were not evident when genotype-guided therapy that included generic clopidogrel was compared with generic clopidogrel for all patients

  7. Effect of myricetin on cytochrome P450 isoforms CYP1A2, CYP2C9 and CYP3A4 in rats.

    PubMed

    Guo, Yu-Jin; Zheng, Shuang-Li

    2014-04-01

    Myricetin is one of the main ingredients of Chinese bayberry, which is used as a traditional medicine. The purpose of this study was to find out whether myricetin influences the rat cytochrome P450 (CYP) enzymes (CYP1A2, CYP2C9 and CYP3A4) by using cocktail probe drugs in vivo. A cocktail solution at a dose of 5 mL/kg, which contained phenacetin (20 mg/kg), tolbutamide (5 mg/kg) and midazolam (10 mg/kg), was orally administered to rats treated for 14 days with myricetin. Blood samples were collected at a series of time-points and the concentrations of probe drugs in plasma were determined by HPLC-MS/MS. The corresponding pharmacokinetic parameters were calculated by the software of DAS 2.0. Our study showed that treatment with multiple doses of myricetin had no effects on rat CYP1A2. However, CYP2C9 and CYP3A4 enzyme activities were inhibited after multiple doses of myricetin. Therefore, caution is needed when myricetin is co-administered with CYP2C9 or CYP3A4 substrates, which may result in herb-drug interactions.

  8. CYP2C19 loss-of-function alleles are not associated with clinical outcome of clopidogrel therapy in patients treated with newer-generation drug-eluting stents

    PubMed Central

    Choi, Ik Jun; Koh, Yoon-Seok; Park, Mahn-Won; Her, Sung Ho; Choi, Yun-Seok; Park, Chul-Soo; Park, Hun-Jun; Kim, Pum-Joon; Chung, Wook-Sung; Kim, Ho-Sook; Shin, Jae-Gook; Seung, Ki-Bae; Chang, Kiyuk

    2016-01-01

    Abstract CYP2C19 loss-of-function (LOF) alleles adversely affect clinical outcome of clopidogrel therapy. Recent introduction of a newer-generation drug-eluting stent (DES) has significantly reduced the occurrence of stent thrombosis. The aim of this study was to evaluate the impact of CYP2C19 LOF alleles on clinical outcome in patients treated with the newer-generation DES. The effects of CYP2C19 genotypes were evaluated on clinical outcome of clopidogrel therapy in 2062 patients treated with percutaneous coronary intervention using either first-generation DES (sirolimus- and paclitaxel-eluting stent, n = 1349) or newer-generation DES (everolimus- and zotarolimus-eluting stent, n = 713). The primary clinical outcome was major cardiac and cerebrovascular event (MACCE) including cardiac death, nonfatal myocardial infarction, stroke, and stent thrombosis during 1 year of follow-up. CYP2C19 LOF alleles were significantly associated with a higher risk of MACCE in patients treated with first-generation DES (hazard ratio [HR] 2.599, 95% confidence interval [CI] 1.047–6.453; P = 0.034). In contrast, CYP2C19 LOF alleles were not associated with primary outcome in newer-generation DES (HR 0.716, 95% CI 0.316–1.622; P = 0.522). In the further multivariate analysis, CYP2C19 LOF alleles were not associated with MACCE in patients receiving newer-generation DES (adjusted HR 0.540, 95% CI 0.226–1.291; P = 0.166), whereas they were demonstrated to be an independent risk factor for MACCE in those implanted with first-generation DES (adjusted HR 3.501, 95% CI 1.194–10.262; P = 0.022). In contradiction to their clinical impact in first-generation DES era, CYP2C19 LOF alleles may not affect clinical outcome of clopidogrel therapy in patients treated with newer-generation DES. PMID:27368038

  9. The correlation between CYP2D6 isoenzyme activity and haloperidol efficacy and safety profile in patients with alcohol addiction during the exacerbation of the addiction

    PubMed Central

    Sychev, Dmitry Alekseevich; Zastrozhin, Mikhail Sergeevich; Smirnov, Valery Valerieevich; Grishina, Elena Anatolievna; Savchenko, Ludmila Mikhailovna; Bryun, Evgeny Alekseevich

    2016-01-01

    Background Today, it is proved that isoenzymes CYP2D6 and CYP3A4 are involved in metabolism of haloperidol. In our previous investigation, we found a medium correlation between the efficacy and safety of haloperidol and the activity of CYP3A4 in patients with alcohol abuse. Objective The aim of this study was to evaluate the correlation between the activity of CYP2D6 and the efficacy and safety of haloperidol in patients with diagnosed alcohol abuse. Methods The study involved 70 men (average age: 40.83±9.92 years) with alcohol addiction. A series of psychometric scales were used in the research. The activity of CYP2D6 was evaluated by high-performance liquid chromatography with mass spectrometry using the ratio of 6-hydroxy-1,2,3,4-tetrahydro-beta-carboline to pinoline. Genotyping of CYP2D6 (1846G>A) was performed using real-time polymerase chain reaction. Results According to results of correlation analysis, statistically significant values of Spearman correlation coefficient (rs) between the activity of CYP2D6 and the difference of points in psychometric scale were obtained in patients receiving haloperidol in injection form (Sheehan Clinical Anxiety Rating Scale =−0.721 [P<0.001] and Udvald for Kliniske Undersogelser Side Effect Rating Scale =0.692 [P<0.001]) and in those receiving haloperidol in tablet form (Covi Anxiety Scale =−0.851 [P<0.001] and Udvald for Kliniske Undersogelser Side Effect Rating Scale =0.797 [P<0.001]). Conclusion This study demonstrated the correlations between the activity of CYP2D6 isozyme and the efficacy and safety of haloperidol in patients with alcohol addiction. PMID:27695358

  10. The correlation between CYP2D6 isoenzyme activity and haloperidol efficacy and safety profile in patients with alcohol addiction during the exacerbation of the addiction

    PubMed Central

    Sychev, Dmitry Alekseevich; Zastrozhin, Mikhail Sergeevich; Smirnov, Valery Valerieevich; Grishina, Elena Anatolievna; Savchenko, Ludmila Mikhailovna; Bryun, Evgeny Alekseevich

    2016-01-01

    Background Today, it is proved that isoenzymes CYP2D6 and CYP3A4 are involved in metabolism of haloperidol. In our previous investigation, we found a medium correlation between the efficacy and safety of haloperidol and the activity of CYP3A4 in patients with alcohol abuse. Objective The aim of this study was to evaluate the correlation between the activity of CYP2D6 and the efficacy and safety of haloperidol in patients with diagnosed alcohol abuse. Methods The study involved 70 men (average age: 40.83±9.92 years) with alcohol addiction. A series of psychometric scales were used in the research. The activity of CYP2D6 was evaluated by high-performance liquid chromatography with mass spectrometry using the ratio of 6-hydroxy-1,2,3,4-tetrahydro-beta-carboline to pinoline. Genotyping of CYP2D6 (1846G>A) was performed using real-time polymerase chain reaction. Results According to results of correlation analysis, statistically significant values of Spearman correlation coefficient (rs) between the activity of CYP2D6 and the difference of points in psychometric scale were obtained in patients receiving haloperidol in injection form (Sheehan Clinical Anxiety Rating Scale =−0.721 [P<0.001] and Udvald for Kliniske Undersogelser Side Effect Rating Scale =0.692 [P<0.001]) and in those receiving haloperidol in tablet form (Covi Anxiety Scale =−0.851 [P<0.001] and Udvald for Kliniske Undersogelser Side Effect Rating Scale =0.797 [P<0.001]). Conclusion This study demonstrated the correlations between the activity of CYP2D6 isozyme and the efficacy and safety of haloperidol in patients with alcohol addiction.

  11. CYP2D6 and UGT2B7 Genotype and Risk of Recurrence in Tamoxifen-Treated Breast Cancer Patients

    PubMed Central

    Drury, Suzy; Hayes, Daniel F.; Stearns, Vered; Thibert, Jacklyn N.; Haynes, Ben P.; Salter, Janine; Sestak, Ivana; Cuzick, Jack; Dowsett, Mitch

    2012-01-01

    Background Adjuvant tamoxifen therapy substantially decreases the risk of recurrence and mortality in women with hormone (estrogen and/or progesterone) receptor–positive breast cancer. Previous studies have suggested that metabolic conversion of tamoxifen to endoxifen by cytochrome P450 2D6 (CYP2D6) is required for patient benefit from tamoxifen therapy. Methods Tumor specimens from a subset of postmenopausal patients with hormone receptor–positive early-stage (stages I, II, and IIIA) breast cancer, who were enrolled in the randomized double-blind Arimidex, Tamoxifen, Alone or in Combination (ATAC) clinical trial, were genotyped for variants in CYP2D6 (N = 1203 patients: anastrozole [trade name: Arimidex] group, n = 615 patients; tamoxifen group, n = 588 patients) and UDP-glucuronosyltransferase-2B7 (UGT2B7), whose gene product inactivates endoxifen (N = 1209 patients; anastrozole group, n = 606 patients; tamoxifen group, n = 603 patients). Genotyping was performed using polymerase chain reaction–based TaqMan assays. Based on the genotypes for CYP2D6, patients were classified as poor metabolizer (PM), intermediate metabolizer (IM), or extensive metabolizer (EM) phenotypes. We evaluated the association of CYP2D6 and UGT2B7 genotype with distant recurrence (primary endpoint) and any recurrence (secondary endpoint) by estimating the hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) using Cox proportional hazards models. All statistical tests were two-sided. Results After a median follow-up of 10 years, no statistically significant associations were observed between CYP2D6 genotype and recurrence in tamoxifen-treated patients (PM vs EM: HR for distant recurrence = 1.25, 95% CI = 0.55 to 3.15, P = .64; HR for any recurrence = 0.99, 95% CI = 0.48 to 2.08, P = .99). A near-null association was observed between UGT2B7 genotype and recurrence in tamoxifen-treated patients. No associations were observed between CYP2D6 and UGT2B7 genotypes and

  12. Influence of CYP2C9, GSTM1, GSTT1 and NAT2 genetic polymorphisms on DNA damage in workers occupationally exposed to organophosphate pesticides.

    PubMed

    Singh, Satyender; Kumar, Vivek; Singh, Priyanka; Banerjee, Basu Dev; Rautela, Rajender Singh; Grover, Shyam Sunder; Rawat, Devendra Singh; Pasha, Syed Tazeen; Jain, Sudhir Kumar; Rai, Arvind

    2012-01-24

    Previous studies have revealed that organophosphate pesticides (OPs) are primarily metabolized by xenobiotic metabolizing enzymes (XMEs). Very few studies have explored genetic polymorphisms of XMEs and their association with DNA damage in pesticides-exposed workers. Present study was designed to determine the influence of CYP2C9, GSTM1, GSTT1 and NAT2 genetic polymorphisms on DNA damage in workers occupationally exposed to OPs. We examined 268 subjects including 134 workers occupationally exposed to OPs and an equal number of normal healthy controls. The DNA damage was evaluated using alkaline comet assay and genotyping was done using individual polymerase chain reaction (PCR) or polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Acetylcholinesterase and paraoxonase activity were found to be significantly lowered in workers as compared to control subjects which were analyzed as biomarkers of toxicity due to OPs exposure (p<0.001). Workers showed significantly higher DNA tail moment (TM) compared to control subjects (14.32±2.17 vs. 6.24±1.37 tail % DNA, p<0.001). GSTM1 null genotype was found to influence DNA TM in workers (p<0.05). DNA TM was also found to be increased with concomitant presence of NAT2 slow acetylation and CYP2C9*3/*3 or GSTM1 null genotypes (p<0.05). DNA TM was found increased in NAT2 slow acetylators with mild and heavy smoking habits in control subjects and workers, respectively (p<0.05). The results of this study suggest that GSTM1 null genotypes, and an association of NAT2 slow acetylation genotypes with CYP2C9*3/*3 or GSTM1 null genotypes may modulate DNA damage in workers occupationally exposed to OPs.

  13. The effects of desvenlafaxine and paroxetine on the pharmacokinetics of the cytochrome P450 2D6 substrate desipramine in healthy adults.

    PubMed

    Nichols, Alice I; Fatato, Penny; Shenouda, Magdy; Paul, Jeffrey; Isler, Jennifer A; Pedersen, Ronald D; Jiang, Qin; Ahmed, Saeeduddin; Patroneva, Albena

    2009-02-01

    The potential for cytochrome P450 (CYP) 2D6 substrates to interact with desvenlafaxine (administered as desvenlafaxine succinate) and paroxetine was evaluated. In an open-label, crossover study, 20 healthy volunteers (aged 21-50) were randomized to 2 series of 9 days each of desvenlafaxine (100 mg/d) or paroxetine (20 mg/d), separated by a 5-day washout. The CYP2D6 substrate desipramine (50 mg) was administered alone on day 1 and coadministered on day 6 of dosing with either desvenlafaxine or paroxetine. CYP2D6 genotype was determined at baseline. Based on least squares geometric mean ratios between reference (desipramine alone) and test treatments, desvenlafaxine produced minor increases in desipramine area under the plasma concentration versus time curve (AUC; 36%) and peak plasma concentration (C(max); 30%) (vs paroxetine: 419%, 90%, respectively; both P < .001). Desvenlafaxine produced little change in 2-hydroxydesipramine AUC (16% increase) and C(max) (0%) versus paroxetine (18% and 82% decreases, respectively; P = .008, P < .001, respectively), indicating that desvenlafaxine, especially at the recommended therapeutic dose of 50 mg/d for major depressive disorder in the United States, has little potential to interact with CYP2D6 substrates.

  14. Role of Pharmacogenetics in Improving the Safety of Psychiatric Care by Predicting the Potential Risks of Mania in CYP2D6 Poor Metabolizers Diagnosed With Bipolar Disorder

    PubMed Central

    Sánchez-Iglesias, Santiago; García-Solaesa, Virginia; García-Berrocal, Belén; Sanchez-Martín, Almudena; Lorenzo-Romo, Carolina; Martín-Pinto, Tomás; Gaedigk, Andrea; González-Buitrago, José Manuel; Isidoro-García, María

    2016-01-01

    Abstract One of the main concerns in psychiatric care is safety related to drug management. Pharmacogenetics provides an important tool to assess causes that may have contributed the adverse events during psychiatric therapy. This study illustrates the potential of pharmacogenetics to identify those patients for which pharmacogenetic-guided therapy could be appropriate. It aimed to investigate CYP2D6 genotype in our psychiatric population to assess the value of introducing pharmacogenetics as a primary improvement for predicting side effects. A broad series of 224 psychiatric patients comprising psychotic disorders, depressive disturbances, bipolar disorders, and anxiety disorders was included. The patients were genotyped with the AmpliChip CYP450 Test to analyzing 33 allelic variants of the CYP2D6 gene. All bipolar patients with poor metabolizer status showed maniac switching when CYP2D6 substrates such as selective serotonin reuptake inhibitors were prescribed. No specific patterns were identified for adverse events for other disorders. We propose to utilize pharmacogenetic testing as an intervention to aid in the identification of patients who are at risk of developing affective switching in bipolar disorder treated with selective serotonin reuptake inhibitors, CYP2D6 substrates, and inhibitors. PMID:26871771

  15. Role of Pharmacogenetics in Improving the Safety of Psychiatric Care by Predicting the Potential Risks of Mania in CYP2D6 Poor Metabolizers Diagnosed With Bipolar Disorder.

    PubMed

    Sánchez-Iglesias, Santiago; García-Solaesa, Virginia; García-Berrocal, Belén; Sanchez-Martín, Almudena; Lorenzo-Romo, Carolina; Martín-Pinto, Tomás; Gaedigk, Andrea; González-Buitrago, José Manuel; Isidoro-García, María

    2016-02-01

    One of the main concerns in psychiatric care is safety related to drug management. Pharmacogenetics provides an important tool to assess causes that may have contributed the adverse events during psychiatric therapy. This study illustrates the potential of pharmacogenetics to identify those patients for which pharmacogenetic-guided therapy could be appropriate. It aimed to investigate CYP2D6 genotype in our psychiatric population to assess the value of introducing pharmacogenetics as a primary improvement for predicting side effects.A broad series of 224 psychiatric patients comprising psychotic disorders, depressive disturbances, bipolar disorders, and anxiety disorders was included. The patients were genotyped with the AmpliChip CYP450 Test to analyzing 33 allelic variants of the CYP2D6 gene.All bipolar patients with poor metabolizer status showed maniac switching when CYP2D6 substrates such as selective serotonin reuptake inhibitors were prescribed. No specific patterns were identified for adverse events for other disorders.We propose to utilize pharmacogenetic testing as an intervention to aid in the identification of patients who are at risk of developing affective switching in bipolar disorder treated with selective serotonin reuptake inhibitors, CYP2D6 substrates, and inhibitors.

  16. Prediction of tamoxifen outcome by genetic variation of CYP2D6 in post-menopausal women with early breast cancer.

    PubMed

    Brauch, Hiltrud; Schwab, Matthias

    2014-04-01

    The question of whether genetic polymorphisms of CYP2D6 can affect treatment outcome in patients with early post-menopausal oestrogen receptor (ER)-positive breast cancer has been a matter of debate over the past few years. In this article we revisit the hypothesis of CYP2D6 being a potential tamoxifen outcome predictor and provide detailed insight into the ongoing controversy that prevented the CYP2D6 marker from being accepted by the scientific and clinical community. We summarize the available pharmacokinetic, pharmacodynamic and pharmacogenetic evidence and resolve the controversy based on the recognized methodological and statistical issues. The cumulative evidence suggests that genotyping for CYP2D6 is clinically relevant in post-menopausal women. This is important, because the clarification of this issue has the potential to resolve a clinical management question that is relevant to hundreds of thousands of women diagnosed with ER-positive breast cancer each year, who should not be denied effective endocrine therapy.

  17. Prediction of tamoxifen outcome by genetic variation of CYP2D6 in post-menopausal women with early breast cancer.

    PubMed

    Brauch, Hiltrud; Schwab, Matthias

    2014-04-01

    The question of whether genetic polymorphisms of CYP2D6 can affect treatment outcome in patients with early post-menopausal oestrogen receptor (ER)-positive breast cancer has been a matter of debate over the past few years. In this article we revisit the hypothesis of CYP2D6 being a potential tamoxifen outcome predictor and provide detailed insight into the ongoing controversy that prevented the CYP2D6 marker from being accepted by the scientific and clinical community. We summarize the available pharmacokinetic, pharmacodynamic and pharmacogenetic evidence and resolve the controversy based on the recognized methodological and statistical issues. The cumulative evidence suggests that genotyping for CYP2D6 is clinically relevant in post-menopausal women. This is important, because the clarification of this issue has the potential to resolve a clinical management question that is relevant to hundreds of thousands of women diagnosed with ER-positive breast cancer each year, who should not be denied effective endocrine therapy. PMID:24033728

  18. Investigation of CYP3A4 and CYP2D6 Interactions of Withania somnifera and Centella asiatica in Human Liver Microsomes.

    PubMed

    Savai, Jay; Varghese, Alice; Pandita, Nancy; Chintamaneni, Meena

    2015-05-01

    Withania somnifera is commonly used as a rejuvenator, whereas Centella asiatica is well known for its anxiolytic and nootropic effects. The present study aims at investigating the effect of crude extracts and principal phytoconstituents of both the medicinal plants with CYP3A4 and CYP2D6 enzyme activity in human liver microsomes (HLM). Phytoconstituents were quantified in the crude extracts of both the medicinal plants using reverse phase HPLC. Crude extracts and phytoconstituents of W. somnifera showed no significant interaction with both CYP3A4 and CYP2D6 enzymes in HLM. Of the crude extracts of C. asiatica screened in vitro, methanolic extract showed potent noncompetitive inhibition of only CYP3A4 enzyme (Ki-64.36 ± 1.82 µg/mL), whereas ethanol solution extract showed potent noncompetitive inhibition of only CYP2D6 enzyme (Ki-36.3 ± 0.44 µg/mL). The flavonoids, quercetin, and kaempferol showed potent (IC50 values less than 100 μM) inhibition of CYP3A4 activity, whereas quercetin alone showed potent inhibition of CYP2D6 activity in HLM. Because methanolic extract of C. asiatica showed a relatively high percentage content of quercetin and kaempferol than ethanol solution extract, the inhibitory effect of methanolic extract on CYP3A4 enzyme activity could be attributed to the flavonoids. Thus, co-administration of the alcoholic extracts of C. asiatica with drugs that are substrates of CYP3A4 and CYP2D6 enzymes may lead to undesirable herb-drug interactions in humans.

  19. The extent and determinants of changes in CYP2D6 and CYP1A2 activities with therapeutic doses of sertraline.

    PubMed

    Ozdemir, V; Naranjo, C A; Herrmann, N; Shulman, R W; Sellers, E M; Reed, K; Kalow, W

    1998-02-01

    The extent of changes in CYP2D6 and CYP1A2 activities with higher therapeutic dosages (>50 mg/day) of sertraline is not well established in vivo. This study assessed the extent and determinants of changes in CYP2D6 and CYP1A2 isozyme activities after treatment with clinically relevant doses of sertraline. Patients and healthy volunteers aged 19 to 85 years (N = 21) were treated with sertraline for 5 to 55 days. The dosage of sertraline ranged from 25 to 150 mg/day (93.5+/-26.4 mg/day; mean +/- SD). All subjects had an extensive metabolizer phenotype for CYP2D6 and received a single oral dose of dextromethorphan (30 mg) and caffeine (100 mg) before and after sertraline treatment. The log O-demethylation ratio (ODMR) of dextromethorphan and the caffeine metabolic ratio (CMR) in overnight urine were used as in vivo indices of the CYP2D6 and CYP1A2 isozyme activities, respectively. Concurrent medications and lifestyle habits (e.g., smoking and diet) were monitored during the study. Baseline log ODMR (-2.33+/-0.45) but not CMR (5.1+/-1.9) (mean +/- SD) significantly changed after sertraline treatment (-2.19+/-0.62; 4.5+/-1.6, respectively) (p: ODMR = 0.04, CMR = 0.10). There was no significant effect of age, dose, duration of treatment, gender, sertraline and/or desmethylsertraline plasma concentration, subject type (patient or volunteer), and weight on the extent of changes in log ODMR or CMR (p > 0.05). In conclusion, sertraline treatment at a mean daily dosage of 94.0 mg did not significantly change CYP1A2 activity and resulted in a modest inhibition of CYP2D6 activity.

  20. Warfarin pharmacogenetics: polymorphisms of the CYP2C9, CYP4F2, and VKORC1 loci in a genetically admixed Omani population.

    PubMed

    Pathare, Anil V; Al Zadjali, Shoaib; Misquith, Rhea; Alkindi, Salam S; Panjwani, Vinodh; Lapoumeroulie, Claudine; Pravin, Sahaya; Paldi, Andras; Krishnamoorthy, Rajagopal

    2012-02-01

    This is the first study to evaluate the spectrum and prevalence of dose-predictive genetic polymorphisms of the CYP2C9, CYP4F2 and VKORC1 loci together, in a geographically defined, ethnically admixed healthy adult Omani population sharing common lifestyle/environmental factors. Since the present-day Omani population is the result of an admixture of Caucasian, African and Asian ancestries, we compared the pharmacogenetic profile of these three loci in this population. Interestingly, the Omani pharmacogenetic profile, in terms of allele and genotype distribution, has values that are intermediate between Caucasians and African Americans, the African admixture further substantiated by the presence of the CYP2C9*8 allele. However, limitations and usefulness of such comparisons warrant caution, as the data from pharmacogenetic literature do not always represent bona fide population categories. Furthermore, definition of study population based on microgeographical scale would be more appropriate in pharmacogenetic research rather than the flawed racial, ethnic, or social categorizations since pharmacogenetic variation is clinal, and genetic influences will be further altered by lifestyle and environmental factors. PMID:22452429

  1. Effect of CYP2C9 and VKORC1 Gene Variants on Warfarin Response in Patients with Continuous-Flow Left Ventricular Assist Devices.

    PubMed

    Topkara, Veli K; Knotts, Robert J; Jennings, Douglas L; Garan, A Reshad; Levin, Allison P; Breskin, Alexander; Castagna, Francesco; Cagliostro, Barbara; Yuzefpolskaya, Melana; Takeda, Koji; Takayama, Hiroo; Uriel, Nir; Mancini, Donna M; Eisenberger, Andrew; Naka, Yoshifumi; Colombo, Paolo C; Jorde, Ulrich P

    2016-01-01

    Bleeding and thrombotic complications continue to plague continuous-flow left ventricular assist device (CF-LVAD) therapy in patients with end-stage heart failure. Warfarin genotyping information can be incorporated into decision making for initial dosing as recommended by the Food and Drug Administration; however, clinical utility of this data in the CF-LVAD population has not been well studied. Genotypes testing for CYP2C9 and VCORC1 polymorphisms were determined in 90 CF-LVAD patients. Outcomes studied were the association of CYP2C9 (*1, *2, or *3) and VKORC1 (-1639 G>A) gene variants with time-to-target international normalized ratio (INR), total warfarin dose, maintenance warfarin dose. Continuous-flow left ventricular assist device patients carrying a rare variant in the VKORC1 gene had a significantly lower cumulative warfarin dose until target INR achieved (18.9 vs. 35.0 mg, p = 0.002), days spent until INR target achieved (4.9 vs. 7.0 days, p = 0.021), and discharge warfarin dose (3.2 vs. 5.6 mg, p = 0.001) compared with patients with wild-type genotype. Genotype-guided warfarin dosing may lead to safer anticoagulation and potentially improve outcomes in CF-LVAD patients. PMID:27258224

  2. Effect of CYP2C9 and VKORC1 Gene Variants on Warfarin Response in Patients with Continuous-Flow Left Ventricular Assist Devices.

    PubMed

    Topkara, Veli K; Knotts, Robert J; Jennings, Douglas L; Garan, A Reshad; Levin, Allison P; Breskin, Alexander; Castagna, Francesco; Cagliostro, Barbara; Yuzefpolskaya, Melana; Takeda, Koji; Takayama, Hiroo; Uriel, Nir; Mancini, Donna M; Eisenberger, Andrew; Naka, Yoshifumi; Colombo, Paolo C; Jorde, Ulrich P

    2016-01-01

    Bleeding and thrombotic complications continue to plague continuous-flow left ventricular assist device (CF-LVAD) therapy in patients with end-stage heart failure. Warfarin genotyping information can be incorporated into decision making for initial dosing as recommended by the Food and Drug Administration; however, clinical utility of this data in the CF-LVAD population has not been well studied. Genotypes testing for CYP2C9 and VCORC1 polymorphisms were determined in 90 CF-LVAD patients. Outcomes studied were the association of CYP2C9 (*1, *2, or *3) and VKORC1 (-1639 G>A) gene variants with time-to-target international normalized ratio (INR), total warfarin dose, maintenance warfarin dose. Continuous-flow left ventricular assist device patients carrying a rare variant in the VKORC1 gene had a significantly lower cumulative warfarin dose until target INR achieved (18.9 vs. 35.0 mg, p = 0.002), days spent until INR target achieved (4.9 vs. 7.0 days, p = 0.021), and discharge warfarin dose (3.2 vs. 5.6 mg, p = 0.001) compared with patients with wild-type genotype. Genotype-guided warfarin dosing may lead to safer anticoagulation and potentially improve outcomes in CF-LVAD patients.

  3. Effects of polymorphisms in CYP2D6 and ABC transporters and side effects induced by gefitinib on the pharmacokinetics of the gefitinib metabolite, O-desmethyl gefitinib.

    PubMed

    Kobayashi, Hiroyuki; Sato, Kazuhiro; Niioka, Takenori; Takeda, Masahide; Okuda, Yuji; Asano, Mariko; Ito, Hiroshi; Miura, Masatomo

    2016-06-01

    We investigated the effects of polymorphisms in CYP2D6, ABCB1, and ABCG2 and the side effects induced by gefitinib on the pharmacokinetics of O-desmethyl gefitinib, the active metabolite of gefitinib. On day 14 after beginning therapy with gefitinib, plasma concentrations of gefitinib and O-desmethyl gefitinib were measured. Patients were grouped into three groups according to their combination of CYP2D6 alleles: homozygous extensive metabolisers (EMs; *1/*1, *1/*2, and *2/*2; n = 13), heterozygous EMs (*1/*5, *2/*5, *1/*10, and *2/*10; n = 18), and intermediate metabolisers (IMs; *5/*10 and *10/*10; n = 5). The median AUC0-24 of O-desmethyl gefitinib in CYP2D6 IMs was 1460 ng h/mL, whereas that in homozygous EMs was 12,523 ng h/mL (P = 0.021 in univariate analysis). The median AUC ratio of O-desmethyl gefitinib to gefitinib differed among homozygous EMs, heterozygous EMs, and IMs at a ratio of 1.41:0.86:0.24 (P = 0.030). On the other hand, there were no significant differences in the AUC0-24 of O-desmethyl gefitinib between ABCB1 and ABCG2 genotypes. In a multivariate analysis, CYP2D6 homozygous EMs (P = 0.012) were predictive for a higher AUC0-24 of O-desmethyl gefitinib. The side effects of diarrhoea, skin rash, and hepatotoxicity induced by gefitinib were unrelated to the AUC0-24 of O-desmethyl gefitinib. CYP2D6 polymorphisms were associated with the formation of O-desmethyl gefitinib from gefitinib. In CYP2D6 homozygous EMs, the plasma concentrations of O-desmethyl gefitinib were higher over 24 h after taking gefitinib than those of the parent compound; however, side effects induced by gefitinib were unrelated to O-desmethyl gefitinib exposure.

  4. A Genome-Wide Association Study Confirms VKORC1, CYP2C9, and CYP4F2 as Principal Genetic Determinants of Warfarin Dose

    PubMed Central

    Bourgeois, Stephane; Barnes, Chris; Eriksson, Niclas; Soranzo, Nicole; Whittaker, Pamela; Ranganath, Venkatesh; Kumanduri, Vasudev; McLaren, William; Holm, Lennart; Lindh, Jonatan; Rane, Anders; Wadelius, Mia; Deloukas, Panos

    2009-01-01

    We report the first genome-wide association study (GWAS) whose sample size (1,053 Swedish subjects) is sufficiently powered to detect genome-wide significance (p<1.5×10−7) for polymorphisms that modestly alter therapeutic warfarin dose. The anticoagulant drug warfarin is widely prescribed for reducing the risk of stroke, thrombosis, pulmonary embolism, and coronary malfunction. However, Caucasians vary widely (20-fold) in the dose needed for therapeutic anticoagulation, and hence prescribed doses may be too low (risking serious illness) or too high (risking severe bleeding). Prior work established that ∼30% of the dose variance is explained by single nucleotide polymorphisms (SNPs) in the warfarin drug target VKORC1 and another ∼12% by two non-synonymous SNPs (*2, *3) in the cytochrome P450 warfarin-metabolizing gene CYP2C9. We initially tested each of 325,997 GWAS SNPs for association with warfarin dose by univariate regression and found the strongest statistical signals (p<10−78) at SNPs clustering near VKORC1 and the second lowest p-values (p<10−31) emanating from CYP2C9. No other SNPs approached genome-wide significance. To enhance detection of weaker effects, we conducted multiple regression adjusting for known influences on warfarin dose (VKORC1, CYP2C9, age, gender) and identified a single SNP (rs2108622) with genome-wide significance (p = 8.3×10−10) that alters protein coding of the CYP4F2 gene. We confirmed this result in 588 additional Swedish patients (p<0.0029) and, during our investigation, a second group provided independent confirmation from a scan of warfarin-metabolizing genes. We also thoroughly investigated copy number variations, haplotypes, and imputed SNPs, but found no additional highly significant warfarin associations. We present power analysis of our GWAS that is generalizable to other studies, and conclude we had 80% power to detect genome-wide significance for common causative variants or markers explaining at least 1

  5. No association between schizophrenia and polymorphisms within the genes for debrisoquine 4-hydroxylase (CYP2D6) and the dopamine transporter (DAT)

    SciTech Connect

    Daniels, J.; Williams, J.; Asherson, P.; McGuffin, P.; Owen, M.

    1995-02-27

    It has been suggested that the cytochrome P450 mono-oxygenase, debrisoquine 4-hydroxylase, is involved in the catabolism and processing of neurotransmitters subsequent to their reuptake into target cells. It is also thought to be related to the dopamine transporter that acts to take released dopamine back up into presynaptic terminals. The present study used the association approach to test the hypothesis that mutations in the genes for debrisoquine 4-hydroxylase (CYP2D6) and the dopamine transporter (DAT) confer susceptibility to schizophrenia. There were no differences in allele or genotype frequencies between patients and controls in the mutations causing the poor metaboliser phenotype in CYP2D6. In addition there was no association found between schizophrenia and a 48 bp repeat within the 3{prime} untranslated region of DAT. 18 refs., 2 tabs.

  6. Population pharmacokinetic approach to evaluate the effect of CYP2D6, CYP3A, ABCB1, POR and NR1I2 genotypes on donepezil clearance

    PubMed Central

    Noetzli, Muriel; Guidi, Monia; Ebbing, Karsten; Eyer, Stephan; Wilhelm, Laurence; Michon, Agnès; Thomazic, Valérie; Stancu, Ioana; Alnawaqil, Abdel-Messieh; Bula, Christophe; Zumbach, Serge; Gaillard, Michel; Giannakopoulos, Panteleimon; von Gunten, Armin; Csajka, Chantal; Eap, Chin B

    2014-01-01

    Aims A large interindividual variability in plasma concentrations has been reported in patients treated with donepezil, the most frequently prescribed antidementia drug. We aimed to evaluate clinical and genetic factors influencing donepezil disposition in a patient population recruited from a naturalistic setting. Methods A population pharmacokinetic study was performed including data from 129 older patients treated with donepezil. The patients were genotyped for common polymorphisms in the metabolic enzymes CYP2D6 and CYP3A, in the electron transferring protein POR and the nuclear factor NR1I2 involved in CYP activity and expression, and in the drug transporter ABCB1. Results The average donepezil clearance was 7.3 l h−1 with a 30% interindividual variability. Gender markedly influenced donepezil clearance (P < 0.01). Functional alleles of CYP2D6 were identified as unique significant genetic covariate for donepezil clearance (P < 0.01), with poor metabolizers and ultrarapid metabolizers demonstrating, respectively, a 32% slower and a 67% faster donepezil elimination compared with extensive metabolizers. Conclusion The pharmacokinetic parameters of donepezil were well described by the developed population model. Functional alleles of CYP2D6 significantly contributed to the variability in donepezil disposition in the patient population and should be further investigated in the context of individual dose optimization to improve clinical outcome and tolerability of the treatment. PMID:24433464

  7. CYP2D6*4 Allele Polymorphism Increases the Risk of Parkinson’s Disease: Evidence from Meta-Analysis

    PubMed Central

    Chen, Siyuan; Xie, Yantong; Peng, Qiliu; He, Yu; Deng, Yan; Wang, Jian; Xie, Li; Zeng, Jie; Li, Shan; Qin, Xue

    2013-01-01

    Background Many epidemiological studies have been conducted to explore the association between a single CYP2D6 gene polymorphism and Parkinson’s disease (PD) susceptibility. However, the results remain controversial. Objectives To clarify the effects of a single CYP2D6 gene polymorphism on the risk of PD, a meta-analysis of all available studies relating to CYP2D6*4 polymorphism and the risk of PD was conducted. Methods A comprehensive literature search of PubMed, EMBASE, and the China National Knowledge Infrastructure (CNKI) up to September 1, 2013 was conducted. Data were extracted by two independent authors and pooled odds ratio (OR) with 95% confidence interval (CI) were calculated. Meta-regression, Galbraith plots, subgroup analysis, sensitivity analysis, and publication bias analysis were also performed. Results Twenty-two separate comparisons consisting of 2,629 patients and 3,601 controls were included in our meta-analysis. The pooled analyses showed a significant association between CYP2D6*4G/A polymorphism and PD risk in all of the comparisons (A vs. G allele: OR = 1.28, 95% CI = 1.14–1.43, P = 0.001; AA vs. GG: OR = 1.43, 95% CI = 1.06–1.93, P = 0.018; AG vs. GG: OR = 1.22, 95% CI = 1.06–1.40, P = 0.006; AG+AA vs. GG: OR = 1.26, 95% CI = 1.10–1.44, P = 0.001; AA vs. AG+GG: OR = 1.37, 95% CI = 1.02–1.83, P = 0.036). In subgroup analysis stratified by ethnicity, significant associations were also demonstrated in Caucasians but not in Asians. No significant association was found in subgroup analysis stratified by age of onset or disease form. Conclusions We concluded that the CYP2D6*4G/A polymorphism denotes an increased genetic susceptibility to PD in the overall population, especially in Caucasians. Further large and well-designed studies are needed to confirm this association. PMID:24376807

  8. The role of CYP2D6 and TaqI A polymorphisms in malignant neuroleptic syndrome: two case reports with three episodes.

    PubMed

    Zivković, Maja; Mihaljević-Peles, Alma; Sagud, Marina; Silić, Ante; Mihanović, Mate

    2010-03-01

    Malignant neuroleptic syndrome (MNS) is a serious and potentially fatal side-effect of neuroleptic treatment. Beside antipsychotic drugs, other psychotropic drugs such as antidepressants and lithium carbonate can cause this life threatening side-effect. Underlying mechanism of this side-effect is still unknown and debated. So far some risk factors have been identified, with clinical observations and recent pharmacogenetic research suggesting (with inconsistent findings) correlation between genetic mechanisms and predisposition to MNS. Polymorphisms of CYP2D6 enzyme through which most psychotropic drugs are metabolized and TaqIA DRD2 which is target for antipsychotic drugs could be the link between pharmacogenetic factors and potential for development of MNS. In this paper we present two case reports with clinical presentation of three consecutive MNS. One patient developed MNS while he was taking combination of drugs: first time haloperidol, promazine and fluphenazine, second time fluphenazine and perazine and third time clozapine, promazine and valproic acid consecutively. The other patient developed MNS while taking following combination of drugs: first time haloperidol and lithium carbonate, second time risperidone and third time clozapine consecutively. Pharmacogenetic analysis for CYP2D6 and TaqI A DRD2 polymorphisms for both patients was done. Genotypisation of CYP2D6*1*3*4*5*6 in both patients showed no evidence of poor metabolizer phenotype. On the other hand, first patient was heterozygous for CYP2D6*4 (genotype *1/*4). CYP2D6 polymorphisms could have clinical significance because may lead to toxicity and unwanted side-effects in standard usual antipsychotic dose ranges. Analysis Taql A DRD2 polymorphism for first patient showed that he is heterozygous for A1 allele (genotype A1A2) which is commonly associated with predisposition to MNS. According to our literature three consecutive MNS are rarely described, and incidence of MNS generally is too low to

  9. Determination of CYP2D6 *3, *4, and *10 frequency in women with breast cancer in São Luís, Brazil, and its association with prognostic factors and disease-free survival

    PubMed Central

    Martins, D.M.F.; Vidal, F.C.B.; Souza, R.D.M.; Brusaca, S.A.; Brito, L.M.O.

    2014-01-01

    The CYP2D6 enzyme is crucial for the metabolism of tamoxifen. The CYP2D6 gene is highly polymorphic, and individuals can be extensive, intermediate, or poor tamoxifen metabolizers. The aim of this study was to determine the frequencies of the CYP2D6 *3, *4, and *10 alleles in women with breast cancer who were treated with tamoxifen and analyze the association of enzyme activity with prognostic factors and disease-free survival. We observed a high frequency of CYP2D6 *10, with an allelic frequency of 0.14 (14.4%). The *3 allele was not present in the studied population, and *4 had an allelic frequency of 0.13 (13.8%). We conclude that patients with reduced CYP2D6 activity did not present worse tumor characteristics or decreased disease-free survival than women with normal enzyme activity, as the difference was not statistically significant. We also observed a high frequency of CYP2D6 *10, which had not been previously described in this specific population. This study is the first in north-northeastern Brazil that aimed to contribute to the knowledge of the Brazilian regional profile for CYP2D6 polymorphisms and their phenotypes. These findings add to the knowledge of the distribution of different polymorphic CYP2D6 alleles and the potential role of CYP2D6 genotyping in clinical practice prior to choosing therapeutic protocols. PMID:25296365

  10. Associations of CYP3A4, NR1I2, CYP2C19 and P2RY12 polymorphisms with clopidogrel resistance in Chinese patients with ischemic stroke

    PubMed Central

    Liu, Rui; Zhou, Zi-yi; Chen, Yi-bei; Li, Jia-li; Yu, Wei-bang; Chen, Xin-meng; Zhao, Min; Zhao, Yuan-qi; Cai, Ye-feng; Jin, Jing; Huang, Min

    2016-01-01

    Aim: There is a high incidence of the antiplatelet drug clopidogrel resistance (CR) in Asian populations. Because clopidogrel is a prodrug, polymorphisms of genes encoding the enzymes involved in its biotransformation may be the primary influential factors. The goal of this study was to investigate the associations of polymorphisms of CYP3A4, NR1I2, CYP2C19 and P2RY12 genes with CR in Chinese patients with ischemic stroke. Methods: A total of 191 patients with ischemic stroke were enrolled. The patients were treated with clopidogrel for at least 5 days. Platelet function was measured by light transmission aggregometry. The SNPs NR1I2 (rs13059232), CYP3A4*1G (rs2242480), CYP2C19*2 (rs4244285) and P2RY12 (rs2046934) were genotyped. Results: The CR rate in this population was 36%. The CYP2C19*2 variant was a risk factor for CR (*2/*2+wt/*2 vs wt/wt, OR: 2.366, 95% CI: 1.180–4.741, P=0.014), whereas the CYP3A4*1G variant had a protective effect on CR (*1/*1 vs *1G/*1G+*1/*1G, OR: 2.360, 95% CI: 1.247–4.468, P=0.008). The NR1I2 (rs13059232) polymorphism was moderately associated with CR (CC vs TT+TC, OR: 0.533, 95% CI: 0.286–0.991, P=0.046). The C allele in P2RY12 (rs2046934) was predicted to be a protective factor for CR (CC+TC vs TT, OR: 0.407, 95% CI: 0.191–0.867, P=0.018). In addition, an association was found between hypertension and CR (P=0.022). Conclusion: The individuals with both the CYP2C19*2 allele and hypertension are at high risk of CR during anti-thrombosis therapy. The CYP3A4*1G allele, P2RY12 (rs2046934) C allele and NR1I2 (rs13059232) CC genotype may be protective factors for CR. The associated SNPs studied may be useful to predict clopidogrel resistance in Chinese patients with ischemic stroke. PMID:27133299

  11. Genetic polymorphisms of CYP2D6*10 and the effectiveness of combined tamoxifen citrate and testosterone undecanoate treatment in infertile men with idiopathic oligozoospermia*

    PubMed Central

    Tang, Kai-fa; Zhao, Yi-li; Ding, Shang-shu; Wu, Qi-fei; Wang, Xing-yang; Shi, Jia-qi; Sun, Fa; Xing, Jun-ping

    2015-01-01

    Tamoxifen citrate, as the first line of treatment for infertile men with idiopathic oligozoospermia, was proposed by the World Health Organization (WHO), and testosterone undecanoate has shown benefits in semen values. Our objective was to assess the effectiveness of treatment with tamoxifen citrate and testosterone undecanoate in infertile men with idiopathic oligozoospermia, and whether the results would be affected by polymorphisms of CYP2D6*10. A total of 230 infertile men and 147 controls were included in the study. Patients were treated with tamoxifen citrate and testosterone undecanoate. Sex hormone, sperm parameters, and incidence of spontaneous pregnancy were detected. There were no significant differences between the control and patient groups with respect to CYP2D6*10 genotype frequencies (P>0.05). The follicle-stimulation hormone (FSH), luteinizing hormone (LH), and testosterone (T) levels were raised, and sperm concentration and motility were increased at 3 months and became significant at 6 months, and they were higher in the wild-type allele (C/C) than in the heterozygous variant allele (C/T) or homozygous variant allele (T/T) subgroups (P<0.05). In addition, the percentage of normal morphology was raised at 6 months, and represented the highest percentage in the C/C subgroup (P<0.05). The incidence of spontaneous pregnancy in the C/C subgroup was higher than that in the C/T or T/T subgroups (P<0.01). This study showed that the CYP2D6*10 variant genotype demonstrated worse clinical effects in infertile men with idiopathic oligozoospermia. PMID:25743120

  12. An assessment of drug-drug interactions: the effect of desvenlafaxine and duloxetine on the pharmacokinetics of the CYP2D6 probe desipramine in healthy subjects.

    PubMed

    Patroneva, Albena; Connolly, Sandra M; Fatato, Penny; Pedersen, Ron; Jiang, Qin; Paul, Jeffrey; Guico-Pabia, Christine; Isler, Jennifer A; Burczynski, Michael E; Nichols, Alice I

    2008-12-01

    A number of antidepressants inhibit the activity of the cytochrome P450 2D6 enzyme system, which can lead to drug-drug interactions. Based on its metabolic profile, desvenlafaxine, administered as desvenlafaxine succinate, a new serotonin-norepinephrine reuptake inhibitor, is not expected to have an impact on activity of CYP2D6. This single-center, randomized, open-label, four-period, crossover study was undertaken to evaluate the effect of multiple doses of desvenlafaxine (100 mg/day, twice the recommended therapeutic dose for major depressive disorder in the United States) and duloxetine (30 mg b.i.d.) on the pharmacokinetics (PK) of a single dose of desipramine (50 mg). A single dose of desipramine was given first to assess its PK. Desvenlafaxine or duloxetine was then administered, in a crossover design, so that steady-state levels were achieved; a single dose of desipramine was then coadministered. The geometric least-square mean ratios (coadministration versus desipramine alone) for area under the plasma concentration versus time curve (AUC) and peak plasma concentrations (C(max)) of desipramine and 2-hydroxydesipramine were compared using analysis of variance. Relative to desipramine alone, increases in AUC and C(max) of desipramine associated with duloxetine administration (122 and 63%, respectively) were significantly greater than those associated with desvenlafaxine (22 and 19%, respectively; P < 0.001). Duloxetine coadministered with desipramine was also associated with a decrease in 2-hydroxydesipramine C(max) that was significant compared with the small increase seen with desvenlafaxine and desipramine (-24 versus 9%; P < 0.001); the difference between changes in 2-hydroxydesipramine AUC did not reach statistical significance (P = 0.054). Overall, desvenlafaxine had a minimal impact on the PK of desipramine compared with duloxetine, suggesting a lower risk for CYP2D6-mediated drug interactions.

  13. Effects of strong CYP2D6 and 3A4 inhibitors, paroxetine and ketoconazole, on the pharmacokinetics and cardiovascular safety of tamsulosin

    PubMed Central

    Troost, Joachim; Tatami, Shinji; Tsuda, Yasuhiro; Mattheus, Michaela; Mehlburger, Ludwig; Wein, Martina; Michel, Martin C

    2011-01-01

    AIM To determine the effect of the strong CYP2D6 inhibitor paroxetine and strong CYP3A4 inhibitor ketoconazole on the pharmacokinetics and safety (orthostatic challenge) of tamsulosin. METHODS Two open-label, randomized, two-way crossover studies were conducted in healthy male volunteers (extensive CYP2D6 metabolizers). RESULTS Co-administration of multiple oral doses of 20 mg paroxetine once daily with a single oral dose of the 0.4 mg tamsulosin HCl capsule increased the adjusted geometric mean (gMean) values of Cmax and AUC(0,∞) of tamsulosin by factors of 1.34 (90% CI 1.21, 1.49) and 1.64 (90% CI 1.44, 1.85), respectively, and increased the terminal half-life (t1/2) of tamsulosin HCl from 11.4 h to 15.3 h. Co-administration of multiple oral doses of 400 mg ketoconazole once dailywith a single oral dose of the 0.4 mg tamsulosin increased the gMean values of Cmax and AUC(0,∞) of tamsulosin by a factor of 2.20 (90% CI 1.96, 2.45) and 2.80 (90% CI 2.56, 3.07), respectively. The terminal half-life was slightly increased from 10.5 h to 11.8 h. These pharmacokinetic changes were not accompanied by clinically significant alterations of haemodynamic responses during orthostatic stress testing. CONCLUSION The exposure to tamsulosin is increased upon co-administration of strong CYP2D6 inhibitors and even more so of strong 3A4 inhibitors, but neither PK alteration was accompanied by clinically significant haemodynamic changes during orthostatic stress testing. PMID:21496064

  14. Comparative inhibitory potential of selected dietary bioactive polyphenols, phytosterols on CYP3A4 and CYP2D6 with fluorometric high-throughput screening.

    PubMed

    Vijayakumar, Thangavel Mahalingam; Kumar, Ramasamy Mohan; Agrawal, Aruna; Dubey, Govind Prasad; Ilango, Kaliappan

    2015-07-01

    Cytochrome P450 (CYP450) inhibition by the bioactive molecules of dietary supplements or herbal products leading to greater potential for toxicity of co-administered drugs. The present study was aimed to compare the inhibitory potential of selected common dietary bioactive molecules (Gallic acid, Ellagic acid, β-Sitosterol, Stigmasterol, Quercetin and Rutin) on CYP3A4 and CYP2D6 to assess safety through its inhibitory potency and to predict interaction potential with co-administered drugs. CYP450-CO complex assay was carried out for all the selected dietary bioactive molecules in isolated rat microsomes. CYP450 concentration of the rat liver microsome was found to be 0.474 nmol/mg protein, quercetin in DMSO has shown maximum inhibition on CYP450 (51.02 ± 1.24 %) but less when compared with positive control (79.02 ± 1.61 %). In high throughput fluorometric assay, IC50 value of quercetin (49.08 ± 1.02-54.36 ± 0.85 μg/ml) and gallic acid (78.46 ± 1.32-83.84 ± 1.06 μg/ml) was lower than other bioactive compounds on CYP3A4 and CYP2D6 respectively but it was higher than positive controls (06.28 ± 1.76-07.74 ± 1.32 μg/ml). In comparison of in vitro inhibitory potential on CYP3A4 and CYP2D6, consumption of food or herbal or dietary supplements containing quercetin and gallic acid without any limitation should be carefully considered when narrow therapeutic drugs are administered together. PMID:26139922

  15. [CYP2D6, CYP3A5, and CYP3A4 gene polymorphism in Russian, Tatar, and Bashkir populations].

    PubMed

    Mustafina, O E; Tuktarova, I A; Karimov, D D; Somova, R sh; Nasibullin, T R

    2015-01-01

    The allele and genotype frequency distribution at polymorphic loci rs3892097 (184G>A) of CYP2D6 gene, rs776746 (6986A>G) of the CYP3A5 gene and rs2740574 (-392A>G) of the CYP3A4 gene in Russians, Tatars, and Bashkirs was examined. Samples were taken from residents of Bashkortostan Republic (1240 men and women aged from 20 to 109 years and consisted of 443 Russians, 517 Tatars, and 280 Bashkirs). Allele identification was conducted using PCR-RFLP or PCR with TaqMan probes. The "nonfunctional" allele rs3892097*A of the CYP2D6 gene was detected in populations of Russians, Tatars, and Bashkirs in 17.2, 9.5, and 7.1% cases, respectively. The rs776746*G allele of the CYP3A5 gene encoding the CYP3A5 isoenzyme with decreased activity was revealed with a frequency of 94.6% in populations of Russians, 94.3% in the Tatar population, and 91.5% in the Bashkir population. The share of the minor allele rs2740574*G of the CYP3A4 was 4.0% in populations of Russians, 0.5% in the Tatar population, and 0.9% in the Bashkir population. It has been previously shown that the rs3892097*A, rs776746*G, and rs2740574*G allele frequencies vary significantly in different world populations. Since allele variants of CYP2D6, CYP3A5, and CYP3A4 genes can play essential role in interindividual and in interethnic differences in the metabolism of many therapeutic agents, the obtained results could be used in the prognosis of pharmacotherapy efficacy in populations of Russians, Tatars, and Bashkirs.

  16. Association of CYP2D6*10 (c.100C>T) polymorphisms with clinical outcome of breast cancer after tamoxifen adjuvant endocrine therapy in Chinese population.

    PubMed

    Lei, Lei; Wang, Xian; Wu, Xiao-Dan; Wang, Zeng; Chen, Zhan-Hong; Zheng, Ya-Bin; Wang, Xiao-Jia

    2016-01-01

    Tamoxifen is the most widely used adjuvant endocrine therapy for breast cancer. However, the pharmacogenetic effect of CYP2D6 on its efficacy remains unclear. Therefore, this study aimed to evaluate the association of CYP2D6*10 (c.100C>T) polymorphisms with clinical outcome in Chinese breast cancer patients. A total of 72 tamoxifen-treated early breast cancer patients were included in this study. CYP2D6*10 (c.100C>T) polymorphisms (C/C: wild type; T/T: homozygous mutant genotype T; C/T: heterozygote genotype C) were detected by pyrosequencing. The plasma concentrations of tamoxifen and its two major active metabolites were determined by liquid chromatography tandem mass spectrometry (LC-MS). Disease-free survival (DFS) and overall survival (OS) were assessed by Kaplan-Meier analysis, while the Cox proportional hazards model was used in multivariate tests for prognostic significance. We found that T/T carrier showed the lowest serum concentration of endoxifen as compared to C/C and C/T carriers (p<0.01). In the subgroup of patients below 40 years of age, T/T carriers appeared to have the shortest DFS and OS as compared to other genotype carriers (p<0.01). When genotypes (C/C, C/T and T/T carriers) and other clinical characteristics were adjusted, tumor size (>2 cm) and grades were independent prognostic factors for DFS but not OS (tumor size >2 cm: HR: 3.870, 95% CI: 1.045-14.330, P = 0.043; tumor grades: HR: 2.230, 95% CI: 1.090-4.562, P = 0.028). In conclusion, the T/T genotype is a negative prognostic factor in young breast cancer patients using tamoxifen. Tumor size (>2 cm) and grades are independent prognostic factors for DFS, when genotype of CYP2D6*10 (c.100C>T) is adjusted. PMID:27648149

  17. Association of CYP2D6*10 (c.100C>T) polymorphisms with clinical outcome of breast cancer after tamoxifen adjuvant endocrine therapy in Chinese population

    PubMed Central

    Lei, Lei; Wang, Xian; Wu, Xiao-dan; Wang, Zeng; Chen, Zhan-hong; Zheng, Ya-bin; Wang, Xiao-jia

    2016-01-01

    Tamoxifen is the most widely used adjuvant endocrine therapy for breast cancer. However, the pharmacogenetic effect of CYP2D6 on its efficacy remains unclear. Therefore, this study aimed to evaluate the association of CYP2D6*10 (c.100C>T) polymorphisms with clinical outcome in Chinese breast cancer patients. A total of 72 tamoxifen-treated early breast cancer patients were included in this study. CYP2D6*10 (c.100C>T) polymorphisms (C/C: wild type; T/T: homozygous mutant genotype T; C/T: heterozygote genotype C) were detected by pyrosequencing. The plasma concentrations of tamoxifen and its two major active metabolites were determined by liquid chromatography tandem mass spectrometry (LC-MS). Disease-free survival (DFS) and overall survival (OS) were assessed by Kaplan-Meier analysis, while the Cox proportional hazards model was used in multivariate tests for prognostic significance. We found that T/T carrier showed the lowest serum concentration of endoxifen as compared to C/C and C/T carriers (p<0.01). In the subgroup of patients below 40 years of age, T/T carriers appeared to have the shortest DFS and OS as compared to other genotype carriers (p<0.01). When genotypes (C/C, C/T and T/T carriers) and other clinical characteristics were adjusted, tumor size (>2 cm) and grades were independent prognostic factors for DFS but not OS (tumor size >2 cm: HR: 3.870, 95% CI: 1.045-14.330, P = 0.043; tumor grades: HR: 2.230, 95% CI: 1.090-4.562, P = 0.028). In conclusion, the T/T genotype is a negative prognostic factor in young breast cancer patients using tamoxifen. Tumor size (>2 cm) and grades are independent prognostic factors for DFS, when genotype of CYP2D6*10 (c.100C>T) is adjusted. PMID:27648149

  18. Association of CYP2D6*10 (c.100C>T) polymorphisms with clinical outcome of breast cancer after tamoxifen adjuvant endocrine therapy in Chinese population

    PubMed Central

    Lei, Lei; Wang, Xian; Wu, Xiao-dan; Wang, Zeng; Chen, Zhan-hong; Zheng, Ya-bin; Wang, Xiao-jia

    2016-01-01

    Tamoxifen is the most widely used adjuvant endocrine therapy for breast cancer. However, the pharmacogenetic effect of CYP2D6 on its efficacy remains unclear. Therefore, this study aimed to evaluate the association of CYP2D6*10 (c.100C>T) polymorphisms with clinical outcome in Chinese breast cancer patients. A total of 72 tamoxifen-treated early breast cancer patients were included in this study. CYP2D6*10 (c.100C>T) polymorphisms (C/C: wild type; T/T: homozygous mutant genotype T; C/T: heterozygote genotype C) were detected by pyrosequencing. The plasma concentrations of tamoxifen and its two major active metabolites were determined by liquid chromatography tandem mass spectrometry (LC-MS). Disease-free survival (DFS) and overall survival (OS) were assessed by Kaplan-Meier analysis, while the Cox proportional hazards model was used in multivariate tests for prognostic significance. We found that T/T carrier showed the lowest serum concentration of endoxifen as compared to C/C and C/T carriers (p<0.01). In the subgroup of patients below 40 years of age, T/T carriers appeared to have the shortest DFS and OS as compared to other genotype carriers (p<0.01). When genotypes (C/C, C/T and T/T carriers) and other clinical characteristics were adjusted, tumor size (>2 cm) and grades were independent prognostic factors for DFS but not OS (tumor size >2 cm: HR: 3.870, 95% CI: 1.045-14.330, P = 0.043; tumor grades: HR: 2.230, 95% CI: 1.090-4.562, P = 0.028). In conclusion, the T/T genotype is a negative prognostic factor in young breast cancer patients using tamoxifen. Tumor size (>2 cm) and grades are independent prognostic factors for DFS, when genotype of CYP2D6*10 (c.100C>T) is adjusted.

  19. In Silico Predictions of Drug - Drug Interactions Caused by CYP1A2, 2C9 and 3A4 Inhibition - a Comparative Study of Virtual Screening Performance.

    PubMed

    Kaserer, Teresa; Höferl, Martina; Müller, Klara; Elmer, Sebastian; Ganzera, Markus; Jäger, Walter; Schuster, Daniela

    2015-06-01

    The cytochrome P450 (CYP) superfamily represents the major enzyme class responsible for the metabolism of exogenous compounds. Investigation of clearance pathways is therefore an integral part in early drug development, as any alteration of metabolic enzymes may markedly influence the toxicological profile and efficacy of novel compounds. In silico methods are widely applied in drug development to complement experimental approaches. Several different tools are available for that purpose, however, for CYP enzymes they have only been applied retrospectively so far. Within this study, pharmacophore- and shape-based models and a docking protocol were generated for the prediction of CYP1A2, 2C9, and 3A4 inhibition. All theoretically validated models, the validated docking workflow, and additional external bioactivity profiling tools were applied independently and in parallel to predict the CYP inhibition of 29 compounds from synthetic and natural origin. After subsequent experimental assessment of the in silico predictions, we analyzed and compared the prospective performance of all methods, thereby defining the suitability of the applied techniques for CYP enzymes. We observed quite substantial differences in the performances of the applied tools, suggesting that the rational selection of that virtual screening method that proved to perform best can largely improve the success rates when it comes to CYP inhibition prediction. PMID:27490388

  20. Drug Modulation of Water–Heme Interactions in Low-Spin P450 Complexes of CYP2C9d and CYP125A1

    PubMed Central

    Conner, Kip P.; Cruce, Alex A.; Krzyaniak, Matthew D.; Schimpf, Alina M.; Frank, Daniel J.; de Montellano, Paul Ortiz; Atkins, William M.; Bowman, Michael K.

    2015-01-01

    Azoles and pyridines are commonly incorporated into small molecule inhibitor scaffolds that target cytochromes P450 (CYPs) as a strategy to increase drug binding affinity, impart isoform-dependent selectivity, and improve metabolic stability. Optical absorbance spectra of the CYP–inhibitor complex are widely used to infer whether these inhibitors are ligated directly to the heme iron as catalytically inert, low-spin (type II) complexes. Here, we show that the low-spin complex between a drug-metabolizing CYP2C9 variant and 4-(3-phenyl-propyl)-1H-1,2,3-triazole (PPT) retains an axial water ligand despite exhibiting elements of “classic” type II optical behavior. Hydrogens of the axial water ligand are observed by pulsed electron paramagnetic resonance (EPR) spectroscopy for both inhibitor-free and inhibitor-bound species and show that inhibitor binding does not displace the axial water. A 15N label incorporated into PPT is 0.444 nm from the heme iron, showing that PPT is also in the active site. The reverse type I inhibitor, LP10, of CYP125A1 from Mycobacterium tuberculosis, known from X-ray crystal structures to form a low-spin water-bridged complex, is found by EPR and by visible and near-infrared magnetic circular dichroism spectroscopy to retain the axial water ligand in the complex in solution. PMID:25591012

  1. Rough Set Theory as an Interpretable Method for Predicting the Inhibition of Cytochrome P450 1A2 and 2D6.

    PubMed

    Burton, Julien; Petit, Joachim; Danloy, Emeric; Maggiora, Gerald M; Vercauteren, Daniel P

    2013-07-01

    Early prediction of ADME properties such as the cytochrome P450 (CYP) mediated drug-drug interactions is an important challenge in the drug discovery area. In this study, we propose to couple an original data mining approach based on Rough Set Theory (RST) to a structural description of molecules. The latter was achieved by using two types of structural keys: (1) the MACCS keys and (2) a set of five in-house fingerprints based on properties of the electron density distributions of chemical groups. The compounds considered are involved in the inhibition of CYP1A2 and CYP2D6. RST allowed the extraction of rules further used as classifiers to predict the inhibitory profile of an independent set of molecules. The results reached prediction accuracies of 90.6 and 88.2 % for CYP1A2 and CYP2D6, respectively. In addition, these classifiers were analyzed to determine which structural fragments were most used for building the rules, revealing relationships between the occurrence of particular molecular fragments and CYP inhibition. The results assessed RST as a suitable tool to build strongly predictive models and infer structure-activity rules associated with potency.

  2. Cytochrome P450 (CYP2D6) Genotype is Associated with Elevated Systolic Blood Pressure in Preterm Infants Following NICU Discharge

    PubMed Central

    Dagle, John M; Fisher, Tyler J; Haynes, Susan E; Berends, Susan K; Brophy, Patrick D; Morriss, Frank H; Murray, Jeffrey C

    2011-01-01

    Objective To determine genetic and clinical risk factors associated with elevated systolic blood pressure (ESBP) in preterm infants following discharge. Study design A convenience cohort of infants <32 weeks gestational age was followed after discharge; we retrospectively identified a subgroup of subjects with ESBP (SBP > 90th percentile for term infants). Genetic testing identified alleles associated with ESBP. Multivariable logistic regression analysis was performed for the outcome ESBP with clinical characteristics and genotype as independent variables. Results Predictors of ESBP were: CYP2D6 (rs28360521) CC genotype (OR 2.92; 95% CI 1.48, 5.79), adjusted for outpatient oxygen therapy (OR 4.53, 95%CI 2.23, 8.81) and history of urinary tract infection (OR 4.68, 95% CI 1.47, 14.86). Maximum SBP was modeled by multivariable linear regression analysis: Maximum SBP = 84.8 mmHg + 6.8 mmHg (if CYP2D6 CC genotype) + 6.8 mmHg (if discharged on supplemental oxygen) + 4.4 mmHg (if received inpatient glucocorticoids) (p=0.0002). Conclusion ESBP is common among preterm infants with residual lung disease following NICU discharge. This study reveals clinical factors associated with ESBP, identifies a candidate gene for further testing, and supports the recommendation that BP be monitored sooner than at age 3 years as suggested for term infants. PMID:21353244

  3. Molecular Dynamics Simulations to Investigate the Influences of Amino Acid Mutations on Protein Three-Dimensional Structures of Cytochrome P450 2D6.1, 2, 10, 14A, 51, and 62.

    PubMed

    Fukuyoshi, Shuichi; Kometani, Masaharu; Watanabe, Yurie; Hiratsuka, Masahiro; Yamaotsu, Noriyuki; Hirono, Shuichi; Manabe, Noriyoshi; Takahashi, Ohgi; Oda, Akifumi

    2016-01-01

    Many natural mutants of the drug metabolizing enzyme cytochrome P450 (CYP) 2D6 have been reported. Because the enzymatic activities of many mutants are different from that of the wild type, the genetic polymorphism of CYP2D6 plays an important role in drug metabolism. In this study, the molecular dynamics simulations of the wild type and mutants of CYP2D6, CYP2D6.1, 2, 10, 14A, 51, and 62 were performed, and the predictions of static and dynamic structures within them were conducted. In the mutant CYP2D6.10, 14A, and 61, dynamic properties of the F-G loop, which is one of the components of the active site access channel of CYP2D6, were different from that of the wild type. The F-G loop acted as the "hatch" of the channel, which was closed in those mutants. The structure of CYP2D6.51 was not converged by the simulation, which indicated that the three-dimensional structure of CYP2D6.51 was largely different from that of the wild type. In addition, the intramolecular interaction network of CYP2D6.10, 14A, and 61 was different from that of the wild type, and it is considered that these structural changes are the reason for the decrease or loss of enzymatic activities. On the other hand, the static and dynamic properties of CYP2D6.2, whose activity was normal, were not considerably different from those of the wild type.

  4. Molecular Dynamics Simulations to Investigate the Influences of Amino Acid Mutations on Protein Three-Dimensional Structures of Cytochrome P450 2D6.1, 2, 10, 14A, 51, and 62

    PubMed Central

    Watanabe, Yurie; Hiratsuka, Masahiro; Yamaotsu, Noriyuki; Hirono, Shuichi; Manabe, Noriyoshi; Takahashi, Ohgi; Oda, Akifumi

    2016-01-01

    Many natural mutants of the drug metabolizing enzyme cytochrome P450 (CYP) 2D6 have been reported. Because the enzymatic activities of many mutants are different from that of the wild type, the genetic polymorphism of CYP2D6 plays an important role in drug metabolism. In this study, the molecular dynamics simulations of the wild type and mutants of CYP2D6, CYP2D6.1, 2, 10, 14A, 51, and 62 were performed, and the predictions of static and dynamic structures within them were conducted. In the mutant CYP2D6.10, 14A, and 61, dynamic properties of the F-G loop, which is one of the components of the active site access channel of CYP2D6, were different from that of the wild type. The F-G loop acted as the “hatch” of the channel, which was closed in those mutants. The structure of CYP2D6.51 was not converged by the simulation, which indicated that the three-dimensional structure of CYP2D6.51 was largely different from that of the wild type. In addition, the intramolecular interaction network of CYP2D6.10, 14A, and 61 was different from that of the wild type, and it is considered that these structural changes are the reason for the decrease or loss of enzymatic activities. On the other hand, the static and dynamic properties of CYP2D6.2, whose activity was normal, were not considerably different from those of the wild type. PMID:27046024

  5. Structural and energetic analysis to provide insight residues of CYP2C9, 2C11 and 2E1 involved in valproic acid dehydrogenation selectivity.

    PubMed

    Bello, Martiniano; Mendieta-Wejebe, Jessica E; Correa-Basurto, José

    2014-07-15

    Docking and molecular dynamics (MD) simulation have been two computational techniques used to gain insight about the substrate orientation within protein active sites, allowing to identify potential residues involved in the binding and catalytic mechanisms. In this study, both methods were combined to predict the regioselectivity in the binding mode of valproic acid (VPA) on three cytochrome P-450 (CYP) isoforms CYP2C9, CYP2C11, and CYP2E1, which are involved in the biotransformation of VPA yielding reactive hepatotoxic intermediate 2-n-propyl-4-pentenoic acid (4nVPA). There are experimental data about hydrogen atom abstraction of the C4-position of VPA to yield 4nVPA, however, there are not structural evidence about the binding mode of VPA and 4nVPA on CYPs. Therefore, the complexes between these CYP isoforms and VPA or 4nVPA were studied to explore their differences in binding and energetic stabilization. Docking results showed that VPA and 4nVPA are coupled into CYPs binding site in a similar conformation, but it does not explain the VPA hydrogen atom abstraction. On the other hand, MD simulations showed a set of energetic states that reorient VPA at the first ns, then making it susceptible to a dehydrogenation reaction. For 4nVPA, multiple binding modes were observed in which the different states could favor either undergo other reaction mechanism or ligand expulsion from the binding site. Otherwise, the energetic and entropic contribution point out a similar behavior for the three CYP complexes, showing as expected a more energetically favorable binding free energy for the complexes between CYPs and VPA than with 4nVPA.

  6. Comparative aromatic hydroxylation and N-demethylation of MPTP neurotoxin and its analogs, N-methylated {beta}-carboline and isoquinoline alkaloids, by human cytochrome P450 2D6

    SciTech Connect

    Herraiz, Tomas . E-mail: therraiz@ifi.csic.es; Guillen, Hugo; Aran, Vicente J.; Idle, Jeffrey R.; Gonzalez, Frank J.

    2006-11-01

    1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxin is a chemical inducer of Parkinson's disease (PD) whereas N-methylated {beta}-carbolines and isoquinolines are naturally occurring analogues of MPTP involved in PD. This research has studied the oxidation of MPTP by human CYP2D6 (CYP2D6*1 and CYP2D6*10 allelic variants) as well as by a mixture of cytochrome P450s-resembling HLM, and the products generated compared with those afforded by human monoamine oxidase (MAO-B). MPTP was efficiently oxidized by CYP2D6 to two main products: MPTP-OH (p-hydroxylation) and PTP (N-demethylation), with turnover numbers of 10.09 min{sup -1} and K {sub m} of 79.36 {+-} 3 {mu}M (formation of MPTP-OH) and 18.95 min{sup -1} and K {sub m} 69.6 {+-} 2.2 {mu}M (PTP). Small amounts of dehydrogenated toxins MPDP{sup +} and MPP{sup +} were also detected. CYP2D6 competed with MAO-B for the oxidation of MPTP. MPTP oxidation by MAO-B to MPDP{sup +} and MPP{sup +} toxins (bioactivation) was up to 3-fold higher than CYP2D6 detoxification to PTP and MPTP-OH. Several N-methylated {beta}-carbolines and isoquinolines were screened for N-demethylation (detoxification) that was not significantly catalyzed by CYP2D6 or the P450s mixture. In contrast, various {beta}-carbolines were efficiently hydroxylated to hydroxy-{beta}-carbolines by CYP2D6. Thus, N(2)-methyl-1,2,3,4-tetrahydro-{beta}-carboline (a close MPTP analog) was highly hydroxylated to 6-hydroxy-N(2)-methyl-1,2,3,4-tetrahydro-{beta}-carboline and a corresponding 7-hydroxy-derivative. Thus, CYP2D6 could participate in the bioactivation and/or detoxification of these neuroactive compounds by an active hydroxylation pathway. The CYP2D6*1 enzymatic variant exhibited much higher metabolism of both MPTP and N(2)-methyl-1,2,3,4-tetrahydro-{beta}-carboline than the CYP2D6*10 variant, highlighting the importance of CYP2D6 polymorphism in the oxidation of these toxins. Altogether, these results suggest that CYP2D6 can play an important role

  7. An experimental and theoretical study on the kinetic isotope effect of C2H6 and C2D6 reaction with OH

    NASA Astrophysics Data System (ADS)

    Khaled, Fethi; Giri, Binod Raj; Szőri, Milán; Viskolcz, Béla; Farooq, Aamir

    2015-11-01

    We report experimental and theoretical results for the deuterated kinetic isotope effect (DKIE) of the reaction of OH with ethane (C2H6) and deuterated ethane (C2D6). The reactions were investigated behind reflected shock waves over 800-1350 K by monitoring OH radicals near 306.69 nm using laser absorption. In addition, high level CCSD(T)/cc-pV(T,Q)Z//MP2/cc-pVTZ quantum chemical and statistical rate theory calculations were performed which agreed very well with the experimental findings. The results reported herein provide the first experimental evidence that DKIE asymptotes to a value of 1.4 at high temperatures.

  8. Binding of bufuralol, dextromethorphan, and 3,4-methylenedioxymethylamphetamine to wild-type and F120A mutant cytochrome P450 2D6 studied by resonance Raman spectroscopy

    SciTech Connect

    Bonifacio, Alois . E-mail: zwan@few.vu.nl

    2006-05-12

    Cytochrome P450 2D6 (CYP2D6) is one of the most important drug-metabolizing enzymes in humans. Resonance Raman data, reported for First time for CYP2D6, show that the CYP2D6 heme is found to be in a six-coordinated low-spin state in the absence of substrates, and it is perturbed to different extents by bufuralol, dextromethorphan, and 3,4-methylenedioxymethylamphetamine (MDMA). Dextromethorphan and MDMA induce in CYP2D6 a significant amount of five-coordinated high-spin heme species and reduce the polarity of its heme-pocket, whereas bufuralol does not. Spectra of the F120A mutant CYP2D6 suggest that Phe{sup 12} is involved in substrate-binding of dextromethorphan and MDMA, being responsible for the spectral differences observed between these two compounds and bufuralol. These differences could be explained postulating a different substrate mobility for each compound in the CYP2D6 active site, consistently with the role previously suggested for Phe{sup 12} in binding dextromethorphan and MDMA.

  9. Variation in Genes Controlling Warfarin Disposition and Response in American Indian and Alaska Native People: CYP2C9, VKORC1, CYP4F2, CYP4F11, GGCX

    PubMed Central

    Yracheta, Joseph; Dillard, Denise A.; Schilling, Brian; Khan, Burhan; Hopkins, Scarlett; Boyer, Bert; Black, Jynene; Wiener, Howard; Tiwari, Hemant K.; Gordon, Adam; Nickerson, Deborah; Tsai, Jesse M.; Farin, Federico M.; Thornton, Timothy A.; Rettie, Allan E.; Thummel, Kenneth E.

    2015-01-01

    Objectives Pharmacogenetic testing is projected to improve health outcomes and reduce the cost of care by increasing therapeutic efficacy and minimizing drug toxicity. American Indian and Alaska Native (AI/AN) people historically have been excluded from pharmacogenetic research and its potential benefits, a deficiency we sought to address. The vitamin K antagonist warfarin is prescribed for prevention of thromboembolic events, although its narrow therapeutic index and wide inter-individual variability necessitate close monitoring of drug response. Therefore, we were interested in variation in CYP2C9, VKORC1, CYP4F2, CYP4F11, and GGCX, which encode enzymes important for the activity of warfarin and synthesis of vitamin K dependent blood clotting factors. Methods We resequenced these genes in 188 AI/AN people in partnership with Southcentral Foundation (SCF) in Anchorage, AK and 94 Yup'ik people living in the Yukon-Kuskokwim Delta of southwest Alaska to identify known or novel function-disrupting variation. We conducted genotyping for specific SNPs in larger cohorts of each study population (380 and 350, respectively). Results We identified high frequencies of the lower-warfarin dose VKORC1 haplotype (−1639G>A and 1173C>T) and the higher-warfarin dose CYP4F2*3 variant. We also identified two relatively common, novel, and potentially function-disrupting variants in CYP2C9 (M1L and N218I), which, along with CYP2C9*3, CYP2C9*2 and CYP2C9*29, predict that a significant proportion of AI/AN people will have decreased CYP2C9 activity. Conclusions Overall, we predict a lower average warfarin dose requirement in AI/AN populations in Alaska than that seen in non-AI/AN populations of the US, a finding consistent with clinical experience in Alaska. PMID:25946405

  10. Stereoselective metabolism of donepezil and steady-state plasma concentrations of S-donepezil based on CYP2D6 polymorphisms in the therapeutic responses of Han Chinese patients with Alzheimer's disease.

    PubMed

    Lu, Jin; Wan, Lili; Zhong, Yuan; Yu, Qi; Han, Yonglong; Chen, Pengguo; Wang, Beiyun; Li, Wei; Miao, Ya; Guo, Cheng

    2015-11-01

    The therapeutic response rates of patients to donepezil vary from 20% to 60%, one of the reasons is their genetic differences in donepezil-metabolizing enzymes, which directly influence liver metabolism. However, the mechanism of donepezil metabolism and that of its enantiomers is unknown. This study evaluated CYP2D6 polymorphisms to elucidate the stereoselective metabolism of donepezil and to confirm the association between the steady-state plasma concentrations of the pharmaco-effective S-donepezil and the therapeutic responses of Han Chinese patients with Alzheimer's disease. The in vitro study of the stereoselective metabolism demonstrated that CYP2D6 is the predominant P450 enzyme that metabolizes donepezil and that different CYP2D6 alleles differentially affect donepezil enantiomers metabolism. A total of 77 Han Chinese patients with Alzheimer's disease were recruited to confirm these results, by measuring their steady-state plasma concentrations of S-donepezil. The related CYP2D6 genes were genotyped. Plasma concentrations of S-donepezil (based on CYP2D6 polymorphisms) were significantly associated with therapeutic responses. This finding suggests that plasma concentrations of S-donepezil influence therapeutic outcomes following treatment with donepezil in Han Chinese patients with Alzheimer's disease. Therefore, determining a patient's steady-state plasma concentration of S-donepezil in combination with their CYP2D6 genotype might be useful for clinically monitoring the therapeutic efficacy of donepezil.

  11. Cytochrome P450 (CYP2C9*2,*3) & vitamin-K epoxide reductase complex (VKORC1 -1639G

    PubMed Central

    Kaur, Anupriya; Khan, Farah; Agrawal, Suraksha S.; Kapoor, Aditya; Agarwal, Surendra K.; Phadke, Shubha R.

    2013-01-01

    Background & objectives: Studies have demonstrated the effect of CYP2C9 (cytochrome P450) and VKORC1 (vitamin K epoxide reductase complex) gene polymorphisms on the dose of acenocoumarol. The data from India about these gene polymorphisms and their effects on acenocoumarol dose are scarce. The aim of this study was to determine the occurrence of CYP2C9*2,*3 and VKORC 1 -1639G>A gene polymorphisms and to study their effects on the dose of acenocoumarol required to maintain a target International Normalized Ratio (INR) in patients with mechanical heart valve replacement. Methods: Patients from the anticoagulation clinic of a tertiary care hospital in north India were studied. The anticoagulation profile, INR (International Normalized Ratio) values and administered acenocoumarol dose were obtained from the clinical records of patients. Determination of the CYP2C9*2,*3 and VKORC1 -1639G>A genotypes was done by PCR-RFLP (restriction fragment length polymorphism). Results: A total of 111 patients were studied. The genotype frequencies of CYP2C9 *1/*1,*1/*2,*1/*3 were as 0.883, 0.072, 0.036 and that of VKORC1 -1639G>A for GG, AG, and AA genotypes were 0.883, 0.090, and 0.027, respectively. The percentage of patients carrying any of the variant alleles of CYP2C9 and VKORC1 in heterozygous or homozygous form was 34% among those receiving a low dose of ≤20 mg/wk while it was 13.8 per cent in those receiving >20 mg/wk (P=0.014). A tendency of lower dose requirements was seen among carriers of the studied polymorphisms. There was considerable variability in the dose requirements of patients with and without variant alleles. Interpretation & conclusions: The study findings point towards the role of CYP2C9 and VKORC1 gene polymorphisms in determining the inter-individual dose variability of acenocoumarol in the Indian patients with mechanical heart valve replacement. PMID:23481074

  12. Influence of the CYP2D6 Isoenzyme in Patients Treated with Venlafaxine for Major Depressive Disorder: Clinical and Economic Consequences

    PubMed Central

    Sicras-Mainar, Antoni; Guijarro, Pablo; Armada, Beatriz; Blanca-Tamayo, Milagrosa; Navarro-Artieda, Ruth

    2014-01-01

    Background Antidepressant drugs are the mainstay of drug therapy for sustained remission of symptoms. However, the clinical results are not encouraging. This lack of response could be due, among other causes, to factors that alter the metabolism of the antidepressant drug. Objective: to evaluate the impact of concomitant administration of CYP2D6 inhibitors or substrates on the efficacy, tolerability and costs of patients treated with venlafaxine for major depressive disorder in clinical practice. Methods We designed an observational study using the medical records of outpatients. Subjects aged ≥18 years who started taking venlafaxine during 2008–2010 were included. Three study groups were considered: no combinations (reference), venlafaxine-substrate, and venlafaxine-inhibitor. The follow-up period was 12 months. The main variables were: demographic data, comorbidity, remission (Hamilton <7), response to treatment, adverse events and costs. The statistical analysis included logistic regression models and ANCOVA, with p values <0.05 considered significant. Results A total of 1,115 subjects were recruited. The mean age was 61.7 years and 75.1% were female. Approximately 33.3% (95% CI: 30.5 to 36.1) were receiving some kind of drug combination (venlafaxine-substrate: 23.0%, and venlafaxine-inhibitor: 10.3%). Compared with the venlafaxine-substrate and venlafaxine-inhibitor groups, patients not taking concomitant drugs had a better response to therapy (49.1% vs. 39.9% and 34.3%, p<0.01), greater remission of symptoms (59.9% vs. 50.2% and 43.8%, p<0.001), fewer adverse events (1.9% vs. 7.0% and 6.1%, p<0.05) and a lower mean adjusted cost (€2,881.7 vs. €4,963.3 and €7,389.1, p<0.001), respectively. All cost components showed these differences. Conclusions The patients treated with venlafaxine alone showed a better response to anti-depressant treatment, greater remission of symptoms, a lower incidence of adverse events and lower healthcare costs. PMID:25369508

  13. [In vivo evaluation of the metabolic ratio of CYP2C9 and CYP1A2 drug markers after administration of afobazole in comparison to standard inducers and inhibitors of cytochromes].

    PubMed

    Novitskaia, Ia G; Gribakina, O G; Kolyvanov, G B; Zherdev, V P; Smirnov, V V; Seredenin, S B

    2013-01-01

    The effect of subchronic peroral administration in effective doses of afobazole (5 mg/kg), and cytochrome P450 inductors (rifampicin, 13.4 mg/kg; phenytoin, 10.4 mg/kg) and inhibitors (fluconazole, 35.7 mg/kg; ciprofloxacin, 44.0 mg/kg) on the metabolic ratio (MR) of drugs-markers of CYP2C9 and CYP1A2 activity was studied in rats. Afobazole did not change the MR of compounds metabolized by the P450 isoforms studied. After peroral administration of standard P450 inductors and inhibitors, statistically significant bidirectional effects were identified, which demonstrated the expedience of administering a complex of selected compounds, markers, and CYP2C9 and CYP1A2 activity modificators for comparative evaluation of the effects of new drugs in rats. It is recommended to evaluate the activity of CYP1A2 by determining the MR for one of two caffeine metabolites, paraxanthine or theobromine, and the activity of CYP2C9 by determining the MR of metabolite Exp-3174 to losartan.

  14. Impact of Cytochrome P450 2D6 Function on the Chiral Blood Plasma Pharmacokinetics of 3,4-Methylenedioxymethamphetamine (MDMA) and Its Phase I and II Metabolites in Humans.

    PubMed

    Steuer, Andrea E; Schmidhauser, Corina; Tingelhoff, Eva H; Schmid, Yasmin; Rickli, Anna; Kraemer, Thomas; Liechti, Matthias E

    2016-01-01

    3,4-methylenedioxymethamphetamine (MDMA; ecstasy) metabolism is known to be stereoselective, with preference for S-stereoisomers. Its major metabolic step involves CYP2D6-catalyzed demethylenation to 3,4-dihydroxymethamphetamine (DHMA), followed by methylation and conjugation. Alterations in CYP2D6 genotype and/or phenotype have been associated with higher toxicity. Therefore, the impact of CYP2D6 function on the plasma pharmacokinetics of MDMA and its phase I and II metabolites was tested by comparing extensive metabolizers (EMs), intermediate metabolizers (IMs), and EMs that were pretreated with bupropion as a metabolic inhibitor in a controlled MDMA administration study. Blood plasma samples were collected from 16 healthy participants (13 EMs and three IMs) up to 24 h after MDMA administration in a double-blind, placebo-controlled, four-period, cross-over design, with subjects receiving 1 week placebo or bupropion pretreatment followed by a single placebo or MDMA (125 mg) dose. Bupropion pretreatment increased the maximum plasma concentration (Cmax) and area under the plasma concentration-time curve from 0 to 24 h (AUC24) of R-MDMA (9% and 25%, respectively) and S-MDMA (16% and 38%, respectively). Bupropion reduced the Cmax and AUC24 of the CYP2D6-dependently formed metabolite stereoisomers of DHMA 3-sulfate, DHMA 4-sulfate, and 4-hydroxy-3-methoxymethamphetamine (HMMA sulfate and HMMA glucuronide) by approximately 40%. The changes that were observed in IMs were generally comparable to bupropion-pretreated EMs. Although changes in stereoselectivity based on CYP2D6 activity were observed, these likely have low clinical relevance. Bupropion and hydroxybupropion stereoisomer pharmacokinetics were unaltered by MDMA co-administration. The present data might aid further interpretations of toxicity based on CYP2D6-dependent MDMA metabolism. PMID:26967321

  15. Impact of Cytochrome P450 2D6 Function on the Chiral Blood Plasma Pharmacokinetics of 3,4-Methylenedioxymethamphetamine (MDMA) and Its Phase I and II Metabolites in Humans

    PubMed Central

    Steuer, Andrea E.; Schmidhauser, Corina; Tingelhoff, Eva H.; Schmid, Yasmin; Rickli, Anna; Kraemer, Thomas; Liechti, Matthias E.

    2016-01-01

    3,4-methylenedioxymethamphetamine (MDMA; ecstasy) metabolism is known to be stereoselective, with preference for S-stereoisomers. Its major metabolic step involves CYP2D6-catalyzed demethylenation to 3,4-dihydroxymethamphetamine (DHMA), followed by methylation and conjugation. Alterations in CYP2D6 genotype and/or phenotype have been associated with higher toxicity. Therefore, the impact of CYP2D6 function on the plasma pharmacokinetics of MDMA and its phase I and II metabolites was tested by comparing extensive metabolizers (EMs), intermediate metabolizers (IMs), and EMs that were pretreated with bupropion as a metabolic inhibitor in a controlled MDMA administration study. Blood plasma samples were collected from 16 healthy participants (13 EMs and three IMs) up to 24 h after MDMA administration in a double-blind, placebo-controlled, four-period, cross-over design, with subjects receiving 1 week placebo or bupropion pretreatment followed by a single placebo or MDMA (125 mg) dose. Bupropion pretreatment increased the maximum plasma concentration (Cmax) and area under the plasma concentration-time curve from 0 to 24 h (AUC24) of R-MDMA (9% and 25%, respectively) and S-MDMA (16% and 38%, respectively). Bupropion reduced the Cmax and AUC24 of the CYP2D6-dependently formed metabolite stereoisomers of DHMA 3-sulfate, DHMA 4-sulfate, and 4-hydroxy-3-methoxymethamphetamine (HMMA sulfate and HMMA glucuronide) by approximately 40%. The changes that were observed in IMs were generally comparable to bupropion-pretreated EMs. Although changes in stereoselectivity based on CYP2D6 activity were observed, these likely have low clinical relevance. Bupropion and hydroxybupropion stereoisomer pharmacokinetics were unaltered by MDMA co-administration. The present data might aid further interpretations of toxicity based on CYP2D6-dependent MDMA metabolism. PMID:26967321

  16. Impact of fraction unbound, CYP3A, and CYP2D6 in vivo activities, and other potential covariates to the clearance of tramadol enantiomers in patients with neuropathic pain.

    PubMed

    de Moraes, Natália V; Lauretti, Gabriela R; Coelho, Eduardo B; Godoy, Ana Leonor P C; Neves, Daniel V; Lanchote, Vera L

    2016-04-01

    The pharmacokinetics of tramadol is characterized by a large interindividual variability, which is partially attributed to polymorphic CYP2D6 metabolism. The contribution of CYP3A, CYP2B6, fraction unbound, and other potential covariates remains unknown. This study aimed to investigate the contribution of in vivo activities of cytochrome P450 (CYP) 2D6 and 3A as well as other potential covariates (CYP2B6 genotype to the SNP g.15631G>T, fraction unbound, age, body weight, creatinine clearance) to the enantioselective pharmacokinetics of tramadol. Thirty patients with neuropathic pain and phenotyped as CYP2D6 extensive metabolizers were treated with a single oral dose of 100 mg tramadol. Multiple linear regressions were performed to determine the contribution of CYP activities and other potential covariates to the clearance of tramadol enantiomers. The apparent total clearances were 44.9 (19.1-102-2) L/h and 55.2 (14.8-126.0) L/h for (+)- and (-)-tramadol, respectively [data presented as median (minimum-maximum)]. Between 79 and 83% of the overall variation in apparent clearance of tramadol enantiomers was explained by fraction unbound, CYP2D6, and CYP3A in vivo activities and body weight. Fraction unbound explained 47 and 41% of the variation in clearance of (+)-tramadol and (-)-tramadol, respectively. Individually, CYP2D6 and CYP3A activities were shown to have moderate contribution on clearance of tramadol enantiomers (11-16% and 11-18%, respectively). In conclusion, factors affecting fraction unbound of drugs (such as hyperglycemia or co-administration of drugs highly bound to plasma proteins) should be monitored, because this parameter dominates the elimination of tramadol enantiomers.

  17. Effect of CYP2C9, CYP4F2 and VKORC1 genetic polymorphisms on pharmacokinetics and pharmacodynamics of mean daily maintenance dose of warfarin in Chinese patients.

    PubMed

    Zhuang, Wenfang; Wen, Wei; Xuan, Binbin; Chen, Yanhong; Cao, Yanan; Sun, Zhixin; Ma, Jun

    2015-03-01

    In this study, we studied the effects of different genetic variants of CYP2C9, VKORC1 and CYP4F2, and clinical factors on the concentration levels of S-warfarin (WF), R-WF and S, R-7-OH-WF, as well as the mean daily maintenance dose of warfarin in 211 patients on warfarin therapy for at least 3 months. The genotypes of single nucleotide polymorphism (SNP), CYP2C9, VKORC1 1173C>T and CYP4F2 were identified by PCR. Plasma concentrations of S-WF and R-WF and S-7-OH-WF, R-7-OH-WF were determined by high-performance liquid chromatography tandem mass spectrometry on chiral columns. The warfarin dosage requirement correlated negatively with age and was in direct proportion to body weight. VKORC1 1173CC carrier had significantly lower dosage requirements than that with the heterozygous VKORC1 1173CT genotype. The concentration of both 7-OH-S-WF and 7-OH-R-WF, and the warfarin dose showed a significant difference. There were significant differences in the concentrations of S-WF and 7-OH-S-WF among the CYP2C9 variants. The concentration of warfarin, 7-OH-WF and warfarin maintenance dose were not affected by the CYP4F2 V433M variant. In conclusion, VKORC1 1173C>T genotype correlates strongly with a lower daily warfarin dose and the concentration of S-7-OH, R-7-OH warfarin in Han Shanghainese patients. In addition, the results not only demonstrated the effect on pharmacodynamics of warfarin, but also enhanced the enzymatic activity of CYP450 to influence the pharmacokinetic of warfarin. PMID:25304014

  18. Correlation of CpG Island Methylation of the Cytochrome P450 2E1/2D6 Genes with Liver Injury Induced by Anti-Tuberculosis Drugs: A Nested Case-Control Study

    PubMed Central

    Zhang, Jinling; Zhu, Xuebin; Li, Yuhong; Zhu, Lingyan; Li, Shiming; Zheng, Guoying; Ren, Qi; Xiao, Yonghong; Feng, Fumin

    2016-01-01

    This study investigated the role of CpG island methylation of the CYP2E1 and CYP2D6 genes in liver injury induced by anti-TB drugs from an epigenetic perspective in a Chinese cohort. A 1:1 matched nested case-control study design was applied. Pulmonary tuberculosis (TB) patients, who underwent standard anti-TB therapy and developed liver injury were defined as cases, while those who did not develop liver injury were defined as control. The two groups were matched in terms of sex, treatment regimen, and age. In 114 pairs of cases, CpG island methylation levels of the CYP2E1 and CYP2D6 genes in plasma cell-free DNA were found to be significantly correlated with the occurrence of anti-TB drug-induced liver injury (ADLI), with odds ratio (OR) values of 2.429 and 3.500, respectively (p < 0.01). Moreover, through multivariate logistic regression analysis, CpG island methylation of the CYP2E1 and CYP2D6 genes in plasma cell-free DNA were found to be significantly correlated with the occurrence of ADLI, with adjusted OR values of 4.390 (95% confidence interval (CI): 1.982–9.724) and 9.193 (95% CI: 3.624–25.888), respectively (p < 0.001). These results suggest that aberrantly elevated methylation of CpG islands of the CYP2E1 and CYP2D6 genes in plasma cell-free DNA may increase the risk of ADLI in Chinese TB patients. PMID:27490558

  19. Molecular dynamics of CYP2D6 polymorphisms in the absence and presence of a mechanism-based inactivator reveals changes in local flexibility and dominant substrate access channels.

    PubMed

    de Waal, Parker W; Sunden, Kyle F; Furge, Laura Lowe

    2014-01-01

    Cytochrome P450 enzymes (CYPs) represent an important enzyme superfamily involved in metabolism of many endogenous and exogenous small molecules. CYP2D6 is responsible for ∼ 15% of CYP-mediated drug metabolism and exhibits large phenotypic diversity within CYPs with over 100 different allelic variants. Many of these variants lead to functional changes in enzyme activity and substrate selectivity. Herein, a molecular dynamics comparative analysis of four different variants of CYP2D6 was performed. The comparative analysis included simulations with and without SCH 66712, a ligand that is also a mechanism-based inactivator, in order to investigate the possible structural basis of CYP2D6 inactivation. Analysis of protein stability highlighted significantly altered flexibility in both proximal and distal residues from the variant residues. In the absence of SCH 66712, *34, *17-2, and *17-3 displayed more flexibility than *1, and *53 displayed more rigidity. SCH 66712 binding reversed flexibility in *17-2 and *17-3, through *53 remained largely rigid. Throughout simulations with docked SCH 66712, ligand orientation within the heme-binding pocket was consistent with previously identified sites of metabolism and measured binding energies. Subsequent tunnel analysis of substrate access, egress, and solvent channels displayed varied bottle-neck radii. Taken together, our results indicate that SCH 66712 should inactivate these allelic variants, although varied flexibility and substrate binding-pocket accessibility may alter its interaction abilities. PMID:25286176

  20. Utilizing Structures of CYP2D6 and BACE1 Complexes To Reduce Risk of Drug–Drug Interactions with a Novel Series of Centrally Efficacious BACE1 Inhibitors

    PubMed Central

    2016-01-01

    In recent years, the first generation of β-secretase (BACE1) inhibitors advanced into clinical development for the treatment of Alzheimer’s disease (AD). However, the alignment of drug-like properties and selectivity remains a major challenge. Herein, we describe the discovery of a novel class of potent, low clearance, CNS penetrant BACE1 inhibitors represented by thioamidine 5. Further profiling suggested that a high fraction of the metabolism (>95%) was due to CYP2D6, increasing the potential risk for victim-based drug–drug interactions (DDI) and variable exposure in the clinic due to the polymorphic nature of this enzyme. To guide future design, we solved crystal structures of CYP2D6 complexes with substrate 5 and its corresponding metabolic product pyrazole 6, which provided insight into the binding mode and movements between substrate/inhibitor complexes. Guided by the BACE1 and CYP2D6 crystal structures, we designed and synthesized analogues with reduced risk for DDI, central efficacy, and improved hERG therapeutic margins. PMID:25781223

  1. Biotinylation of glycan chains in β2 glycoprotein I induces dimerization of the molecule and its detection by the human autoimmune anti-cardiolipin antibody EY2C9

    PubMed Central

    Dupuy d'Angeac, Arnaud; Stefas, Ilias; Graafland, Hubert; de Lamotte, Frédéric; Rucheton, Marcel; Palais, Caroline; Eriksson, Anna-Karin; Bosc, Priscille; Rosé, Caroline; Chicheportiche, Robert

    2005-01-01

    Binding of β2GPI (β2 glycoprotein I), a human plasma protein, to AnPLs (anionic phospholipids) plays a key role in the formation of antiphospholipid antibodies involved in autoimmune diseases like antiphospholipid syndrome or systemic lupus erythematosus. We recently showed that binding of β2GPI to AnPLs was enhanced by biotinylation of its glycan chains with biotin-hydrazide. In the present study, we investigated why this chemical modification of β2GPI increased both its affinity for AnPLs and its recognition by anti-cardiolipin antibodies. Electrophoretic analysis showed that: (i) high molecular mass β2GPI (dimers and other oligomers) covalently coupled by imine bonds, were present in variable amounts in oxidized β2GPI and in β2GPI-bh (β2GPI-biotin-hydrazide), but were absent in native β2GPI; (ii) binding of β2GPI-bh to phosphatidylserine-coated microtitre plates generated high molecular mass polymers in a time-dependent manner. Native β2GPI did not polymerize in these conditions. These polymers did not bind more strongly to AnPLs than the monomer β2GPI. However, in solution at 1 μM β2GPI-bh essentially appeared as a dimer as revealed by light-scattering analysis. SPR (surface plasmon resonance) analysis showed that the increased affinity of β2GPI-bh for AnPL monolayers was due to a lower dissociation rate constant compared with native β2GPI. Finally, the monoclonal human aCL (auto-immune anti-cardiolipin antibody) EY2C9 bound to β2GPI-bh but did not bind to monomeric native and oxidized β2GPI. It is likely that the dimeric quaternary structure of β2GPI-bh is in fact responsible for the appearance of the epitopes targeted by the EY2C9 antibody. PMID:16097953

  2. An evaluation of the CYP2D6 and CYP3A4 inhibition potential of metoprolol metabolites and their contribution to drug-drug and drug-herb interaction by LC-ESI/MS/MS.

    PubMed

    Borkar, Roshan M; Bhandi, Murali Mohan; Dubey, Ajay P; Ganga Reddy, V; Komirishetty, Prashanth; Nandekar, Prajwal P; Sangamwar, Abhay T; Kamal, Ahmed; Banerjee, Sanjay K; Srinivas, R

    2016-10-01

    The aim of the present study was to evaluate the contribution of metabolites to drug-drug interaction and drug-herb interaction using the inhibition of CYP2D6 and CYP3A4 by metoprolol (MET) and its metabolites. The peak concentrations of unbound plasma concentration of MET, α-hydroxy metoprolol (HM), O-desmethyl metoprolol (ODM) and N-desisopropyl metoprolol (DIM) were 90.37 ± 2.69, 33.32 ± 1.92, 16.93 ± 1.70 and 7.96 ± 0.94 ng/mL, respectively. The metabolites identified, HM and ODM, had a ratio of metabolic area under the concentration-time curve (AUC) to parent AUC of ≥0.25 when either total or unbound concentration of metabolite was considered. In vitro CYP2D6 and CYP3A4 inhibition by MET, HM and ODM study revealed that MET, HM and ODM were not inhibitors of CYP3A4-catalyzed midazolam metabolism and CYP2D6-catalyzed dextromethorphan metabolism. However, DIM only met the criteria of >10% of the total drug related material and <25% of the parent using unbound concentrations. If CYP inhibition testing is solely based on metabolite exposure, DIM metabolite would probably not be considered. However, the present study has demonstrated that DIM contributes significantly to in vitro drug-drug interaction. Copyright © 2016 John Wiley & Sons, Ltd.

  3. Progression of cervical intraepithelial neoplasia to cervical cancer: interactions of cytochrome P450 CYP2D6 EM and glutathione s-transferase GSTM1 null genotypes and cigarette smoking.

    PubMed Central

    Warwick, A. P.; Redman, C. W.; Jones, P. W.; Fryer, A. A.; Gilford, J.; Alldersea, J.; Strange, R. C.

    1994-01-01

    The factors that determine progression of cervical intraepithelial neoplasia (CIN) to squamous cell carcinoma (SCC) are unknown. Cigarette smoking is an independent risk factor for cervical neoplasia, suggesting that polymorphism at detoxicating enzyme loci such as cytochrome P450 CYP2D6 and glutathione S-transferase GSTM1 may determine susceptibility to these cancers. We have studied the frequencies of genotypes at these loci in women suffering low-grade CIN, high-grade CIN and SCC. A non-cancer control group was provided by women with normal cervical histology suffering menorrhagia. Comparison of the frequency distributions of the CYP2D6 PM, HET and EM genotypes (G-->A transition at intron 3/exon 4 and base pair deletion in exon 5) revealed no significant differences between the menorrhagia and SCC groups. Frequency distributions in the menorrhagia group, however, were significantly different (P < 0.04) from those in the low- and high-grade CIN groups. Thus, the proportion of EM was significantly larger (P < 0.03) and of HET generally lower. We found that the frequency of GSTM1 null in the menorrhagia and case groups was not significantly different. Interactive effects of enzyme genotypes with cigarette smoking were studied by comparing the multinomial frequency distributions of CYP2D6 EM/GSTM1 null/smoking over mutually exclusive categories. These showed no significant differences between the menorrhagia group and SCC or low-grade CIN groups. The frequency distribution in high-grade CIN, however, was significantly different to that in the menorrhagia group and in both SCC and low-grade CIN groups. This study was identified, for the first time, an inherited characteristic in women with high-grade CIN who appear to be at reduced risk of SCC. Thus, women with CYP2D6 EM who smoke have increased susceptibility to high-grade CIN but are less likely to progress to SCC, possibly because they effectively detoxify an unidentified chemical involved in mediating disease

  4. Modeling chemical interaction profiles: I. Spectral data-activity relationship and structure-activity relationship models for inhibitors and non-inhibitors of cytochrome P450 CYP3A4 and CYP2D6 isozymes.

    PubMed

    McPhail, Brooks; Tie, Yunfeng; Hong, Huixiao; Pearce, Bruce A; Schnackenberg, Laura K; Ge, Weigong; Valerio, Luis G; Fuscoe, James C; Tong, Weida; Buzatu, Dan A; Wilkes, Jon G; Fowler, Bruce A; Demchuk, Eugene; Beger, Richard D

    2012-03-15

    An interagency collaboration was established to model chemical interactions that may cause adverse health effects when an exposure to a mixture of chemicals occurs. Many of these chemicals--drugs, pesticides, and environmental pollutants--interact at the level of metabolic biotransformations mediated by cytochrome P450 (CYP) enzymes. In the present work, spectral data-activity relationship (SDAR) and structure-activity relationship (SAR) approaches were used to develop machine-learning classifiers of inhibitors and non-inhibitors of the CYP3A4 and CYP2D6 isozymes. The models were built upon 602 reference pharmaceutical compounds whose interactions have been deduced from clinical data, and 100 additional chemicals that were used to evaluate model performance in an external validation (EV) test. SDAR is an innovative modeling approach that relies on discriminant analysis applied to binned nuclear magnetic resonance (NMR) spectral descriptors. In the present work, both 1D ¹³C and 1D ¹⁵N-NMR spectra were used together in a novel implementation of the SDAR technique. It was found that increasing the binning size of 1D ¹³C-NMR and ¹⁵N-NMR spectra caused an increase in the tenfold cross-validation (CV) performance in terms of both the rate of correct classification and sensitivity. The results of SDAR modeling were verified using SAR. For SAR modeling, a decision forest approach involving from 6 to 17 Mold2 descriptors in a tree was used. Average rates of correct classification of SDAR and SAR models in a hundred CV tests were 60% and 61% for CYP3A4, and 62% and 70% for CYP2D6, respectively. The rates of correct classification of SDAR and SAR models in the EV test were 73% and 86% for CYP3A4, and 76% and 90% for CYP2D6, respectively. Thus, both SDAR and SAR methods demonstrated a comparable performance in modeling a large set of structurally diverse data. Based on unique NMR structural descriptors, the new SDAR modeling method complements the existing SAR

  5. In vitro inhibitory effects of asiaticoside and madecassoside on human cytochrome P450.

    PubMed

    Winitthana, T; Niwattisaiwong, N; Patarapanich, C; Tantisira, M H; Lawanprasert, S

    2011-06-01

    The inhibitory effects and types of inhibition of asiaticoside and madecassoside on human CYPs were studied in vitro using recombinant human CYPs. The median inhibitory concentrations (IC50) of asiaticoside and madecassoside were determined for CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP3A4. Asiaticoside inhibited CYP2C19 (IC50 = 412.68 ± 15.44 μM) and CYP3A4 (IC50=343.35 ± 29.35 μM). Madecassoside also inhibited CYP2C19 (IC50 = 539.04 ± 14.18 μM) and CYP3A4 (IC50 = 453.32 ± 39.33 μM). Asiaticoside and madecassoside had no effect on the activities of CYP1A2, CYP2C9 and CYP2D6 and CYP2E1. Assessment of mechanism-based inhibition and the type of inhibition were performed for asiaticoside and madecassoside with CYP2C19 and CYP3A4. These results suggested that madecassoside is a mechanism-based inhibitor of CYP2C19 and CYP3A4. Assessment of mechanism-based inhibition by asiaticoside was limited by its low solubility. Asiaticoside exhibited non-competitive inhibition of CYP2C19 (Ki=385.24 ± 8.75 μM) and CYP3A4 (Ki = 535.93 ± 18.99 μM). Madecassoside also showed non-competitive inhibition of CYP2C19 (Ki = 109.62 ± 6.14 μM) and CYP3A4 (Ki = 456.84 ± 16.43 μM). These results suggest that asiaticoside and madecassoside could cause drug-drug interactions via inhibition of CYP2C19 and CYP3A4. An in vivo study is needed to examine this further.

  6. Contribution of the activities of CYP3A, CYP2D6, CYP1A2 and other potential covariates to the disposition of methadone in patients undergoing methadone maintenance treatment

    PubMed Central

    Shiran, Mohammad-Reza; Lennard, Martin S; Iqbal, Mohammad-Zafar; Lagundoye, Oldwale; Seivewright, Nicholas; Tucker, Geoffrey T; Rostami-Hodjegan, Amin

    2009-01-01

    AIMS To investigate the influence of different cytochrome P450 (CYP) activities and other potential covariates on the disposition of methadone in patients on methadone maintenance therapy (MMT). METHODS Eighty-eight patients (58 male; 21–55 years; 84 White) on MMT were studied. CYP2D6 activity [3 h plasma metabolic ratio of dextromethorphan (DEX) to dextrorphan (DOR)] was determined in 44 patients (29 male; 24–55 years), CYP1A2 activity (salivary caffeine elimination half-life) in 44 patients (21 male; 24–55 years) and CYP3A activity (oral clearance of midazolam) in 49 patients (33 male; 23–55 years). Data on all three CYPs were obtained from 32 subjects. Total plasma concentrations of (RS)-methadone and total and unbound plasma concentrations of both enantiomers were measured by LC/MS. Population pharmacokinetics and subsequent multiple regression analysis were used to calculate methadone oral clearance and to identify its covariates. RESULTS Between 61 and 68% of the overall variation in total plasma trough concentrations of (RS)-, (R)- and (S)-methadone was explained by methadone dose, duration of addiction before starting MMT, CYP3A activity and illicit morphine use. CYP3A activity explained 22, 16, 15 and 23% of the variation in unbound (R)-, unbound (S)-, total (RS)- and total (S)-methadone clearances, respectively. Neither CYP2D6 nor CYP1A2 activity was related to methadone disposition. CONCLUSIONS CYP3A activity has a modest influence on methadone disposition. Inhibitors and inducers of this enzyme should be monitored in patients taking methadone. PMID:19133059

  7. Inhibition of Cytochrome P450 by Propolis in Human Liver Microsomes

    PubMed Central

    Ryu, Chang Seon; Oh, Soo Jin; Oh, Jung Min; Lee, Ji-Yoon; Lee, Sang Yoon; Chae, Jung-woo; Kwon, Kwang-il; Kim, Sang Kyum

    2016-01-01

    Although propolis is one of the most popular functional foods for human health, there have been no comprehensive studies of herb-drug interactions through cytochrome P450 (CYP) inhibition. The purpose of this study was to determine the inhibitory effects of propolis on the activities of CYP1A2, 2A6, 2B6, 2C9, 2C19, 2D6, 2E1 and 3A4 using pooled human liver microsomes (HLMs). Propolis inhibited CYP1A2, CYP2E1 and CYP2C19 with an IC50 value of 6.9, 16.8, and 43.1 μg/mL, respectively, whereas CYP2A6, 2B6, 2C9, 2D6, and 3A4 were unaffected. Based on half-maximal inhibitory concentration shifts between microsomes incubated with and without nicotinamide adenine dinucleotide phosphate, propolis-induced CYP1A2, CYP2C19, and CYP2E1 inhibition was metabolism-independent. To evaluate the interaction potential between propolis and therapeutic drugs, the effects of propolis on metabolism of duloxetine, a serotonin-norepinephrine reuptake inhibitor, were determined in HLMs. CYP1A2 and CYP2D6 are involved in hydroxylation of duloxetine to 4-hydroxy duloxetine, the major metabolite, which was decreased following propolis addition in HLMs. These results raise the possibility of interactions between propolis and therapeutic drugs metabolized by CYP1A2. PMID:27437087

  8. The effects of azole-based heme oxygenase inhibitors on rat cytochromes P450 2E1 and 3A1/2 and human cytochromes P450 3A4 and 2D6.

    PubMed

    Hum, Maaike; McLaughlin, Brian E; Roman, Gheorghe; Vlahakis, Jason Z; Szarek, Walter A; Nakatsu, Kanji

    2010-09-01

    Heme oxygenases (HOs) catalyze the degradation of heme to biliverdin, carbon monoxide (CO), and free iron. The two major isoforms, HO-1 (inducible) and HO-2 (constitutive), are involved in a variety of physiological functions, including inflammation, apoptosis, neuromodulation, and vascular regulation. Major tools used in exploring these actions have been metalloporphyrin analogs of heme that inhibit the HOs. However, these tools are limited by their lack of selectivity; they affect other heme-dependent enzymes, such as cytochromes P450 (P450s), soluble guanylyl cyclase (sGC), and nitric-oxide synthase (NOS). Our laboratory has successfully synthesized a number of nonporphyrin azole-based HO inhibitors (QC-xx) that had little or no effect on sGC and NOS activity. However, their effects on various P450 isoforms have yet to be fully elucidated. To determine the effects of the QC-xx inhibitors on P450 enzyme activity, microsomal preparations of two rat P450 isoforms (2E1 and 3A1/3A2) and two human P450 supersome isoforms (3A4 and 2D6) were incubated with varying concentrations of HO inhibitor, and the activity was determined by spectrophotometric or fluorometric analysis. Results indicated that some QC compounds demonstrated little to no inhibition of the P450s, whereas others did inhibit these P450 isoforms. Four structural regions of QC-xx were analyzed, leading to the identification of structures that confer a decreased effect on both rat and human P450 isoforms studied while maintaining an inhibitory effect on the HOs.

  9. Inhibition of human cytochrome P450 enzymes by licochalcone A, a naturally occurring constituent of licorice.

    PubMed

    He, Wei; Wu, Jing-Jing; Ning, Jing; Hou, Jie; Xin, Hong; He, Yu-Qi; Ge, Guang-Bo; Xu, Wei

    2015-10-01

    Licochalcone A (LCA) is a major bioactive compound in traditional Chinese herbal liquorice that possesses multiple pharmacological activities. However, the effects of the potential herb-drug interactions (HDIs) between LCA and therapeutic drugs on the inhibition of human cytochrome P450 (CYP) enzymes remain unclear. In the present study, the inhibitory effects of LCA on seven major human CYP isoforms, including CYP1A2, 2D6, 2E1, 2C19, 2C8, 2C9 and 3A4, were investigated in human liver microsomes (HLMs). The results demonstrated that LCA significantly inhibited the activities of CYP1A2, 2C19, 2C8, 2C9 and 3A4 and exhibited weak inhibitory effects on CYP2E1 and CYP2D6. Dixon and Lineweaver-Burk plots revealed that the inhibition types of LCA against CYP1A2, 2C9, 2C19 and 2C8 were best fit as mixed-type inhibitions, while LCA was a competitive inhibitor towards CYP3A4. The inhibition kinetic parameters (K(i)) were calculated to be 1.02 μM, 0.17 μM, 3.89 μM 0.89 μM, and 2.29 μM, for CYP1A2, 2C9, 2C19, 2C8, and 3A4, respectively. Furthermore, the areas under the plasma concentration-time curves (AUCs) of several drugs that are primarily metabolized by CYPs were estimated to increase by 2-398% in the presence of LCA, which suggested that LCA exhibited high HDI potentials via CYP inhibition. These data are significant for the clinical applications of LCA-containing herbs.

  10. [Effect of Fuzheng Huayu recipe on CYP450 isozymes in normal and liver fibrosis rats].

    PubMed

    Zheng, Tian-hui; Liu, Wei; Li, Shu-ping; Yang, Tao; Wang, Chang-hong; Liu, Cheng-hai

    2015-03-01

    To study the effect of Fuzheng Huayu recipe (FZHY) on five types of isozymes of cytochrome P450 (CYP450) of normal and liver fibrosis rats by using the cocktail probe method. Dimethylnitrosamine ( DMN) was injected to induce the liver fibrosis model. After the tail vein injection with Cocktail probe solutions prepared with five CYP450s probe substrates (phenacetin-CYP1A2, omeprazole-CYP2C9, tolbutamide-CYP2C19, dextromethorphan-CYP2D6, midazolam-CYP3A4), the plasma concentrations of the five probe substrates were determined by LC-MS/MS, and the pharmacokinetic parameters were calculated by PK solutions 2. After the oral administration with FZHY, normal rats given phenacetin, omeprazole, tolbutamide and dextromethorphan showed increase in AUC(0-t) and decrease in CL to varying degrees, indicating that FZHY obviously inhibited the activities of CYP1A2, CYP2C9, CYP2C19 and CYP2D6 in normal rats, but with no obvious effect on the activity of CYP3A4. After the oral administration with FZHY, liver fibrosis rats treated with CYP2C9 showed the significant increase in AUC(0-t) and significant decrease in Vd, hut with no obvious changes in the pharmacokinetic parameters of other four types of prove substances, suggesting that FZHY could significantly inhibit the activity of CYP2C9 in rats but had no effect on the activities of CYP1A2, CYP2C19, CYP2D6 and CYP3A4. The changes in the activity of CYP450 isozymes in liver fibrosis rats may be the reason for FZHY's different effects on CYP450 isozymes in normal and liver fibrosis rats. PMID:26226765

  11. Pungent ginger components modulates human cytochrome P450 enzymes in vitro

    PubMed Central

    Li, Mian; Chen, Pei-zhan; Yue, Qing-xi; Li, Jing-quan; Chu, Rui-ai; Zhang, Wei; Wang, Hui

    2013-01-01

    Aim: Ginger rhizome is used worldwide as a spicy flavor agent. This study was designed to explore the potential effects of pungent ginger components, 6-, 8-, and 10-gingerol, on human cytochrome P450 (CYP450) enzymes that are responsible for the metabolism of many prescription drugs. Methods: The activities of human CYP2C9, CYP2C19, CYP2D6, and CYP3A4 were analyzed using Vivid P450 assay kits. The mRNA expression of CYP3A4 in human hepatocellular carcinoma cell line HepG2 was measured using quantitative real-time PCR assay. Results: All three gingerols potently inhibited CYP2C9 activity, exerted moderate inhibition on CYP2C19 and CYP3A4, and weak inhibion on CYP2D6. 8-Gingerol was the most potent in inhibition of P450 enzymes with IC50 values of 6.8, 12.5, 8.7, and 42.7 μmol/L for CYP2C9, CYP2C19, CYP3A4, and CYP2D6, respectively. By comparing the effects of gingerols on CYP3A4 with three different fluorescent substrate probes, it was demonstrated that the inhibition of gingerols on CYP3A4 had no substrate-dependence. In HepG2 cells, 8-gingerol and 10-gingerol inhibited, but 6-gingerol induced mRNA expression of CYP3A4. Conclusion: 6-, 8-, and 10-gingerol suppress human cytochrome P450 activity, while 8- and 10-gingerol inhibit CYP3A4 expression. The results may have an implication for the use of ginger or ginger products when combined with therapeutic drugs that are metabolized by cytochrome P450 enzymes. PMID:23770984

  12. The Effect of Vinpocetine on Human Cytochrome P450 Isoenzymes by Using a Cocktail Method

    PubMed Central

    Kong, Lingti; Song, Chunli; Ye, Linhu; Guo, Daohua; Yu, Meiling; Xing, Rong

    2016-01-01

    Vinpocetine is a derivative of the alkaloid vincamine, which had been prescribed for chronic cerebral vascular ischemia and acute ischemic stroke or used as a dietary supplement for its several different mechanisms of biological activities. However, information on the cytochrome P450 (CYP) enzyme-mediated drug metabolism has not been previously studied. The present study was performed to investigate the effects of vinpocetine on CYPs activity, and cocktail method was used, respectively. To evaluate the effects of vinpocetine on the activity of human CYP3A4, CYP2C9, CYP2C19, CYP2D6, and CYP2E1, human liver microsomes were utilized to incubate with the mixed CYPs probe substrates and the target components. The results indicate that vinpocetine exhibited weak inhibitory effect on the CYP2C9, where the IC50 value is 68.96 μM, whereas the IC50 values for CYP3A4, CYP2C19, CYP2D6, and CYP2E1 were all over range of 100 μM, which showed that vinpocetine had no apparent inhibitory effects on these CYPs. In conclusion, the results indicated that drugs metabolized by CYP2C9 coadministrated with vinpocetine may require attention or dose adjustment. PMID:27006677

  13. CYP450 phenotyping and metabolite identification of quinine by accurate mass UPLC-MS analysis: a possible metabolic link to blackwater fever

    PubMed Central

    2013-01-01

    Background The naturally occurring alkaloid drug, quinine is commonly used for the treatment of severe malaria. Despite centuries of use, its metabolism is still not fully understood, and may play a role in the haemolytic disorders associated with the drug. Methods Incubations of quinine with CYPs 1A2, 2C9, 2C19, 2D6, and 3A4 were conducted, and the metabolites were characterized by accurate mass UPLC-MSE analysis. Reactive oxygen species generation was also measured in human erythrocytes incubated in the presence of quinine with and without microsomes. Results The metabolites 3-hydroxyquinine, 2’-oxoquininone, and O-desmethylquinine were observed after incubation with CYPs 3A4 (3-hydroxyquinine and 2’-oxoquininone) and 2D6 (O-desmethylquinine). In addition, multiple hydroxylations were observed both on the quinoline core and the quinuclidine ring system. Of the five primary abundance CYPs tested, 3A4, 2D6, 2C9, and 2C19 all demonstrated activity toward quinine, while 1A2 did not. Further, quinine produced robust dose-dependent oxidative stress in human erythrocytes in the presence of microsomes. Conclusions Taken in context, these data suggest a CYP-mediated link between quinine metabolism and the poorly understood haemolytic condition known as blackwater fever, often associated with quinine ingestion. PMID:23800033

  14. Activity levels of tamoxifen metabolites at the estrogen receptor and the impact of genetic polymorphisms of phase I and II enzymes on their concentration levels in plasma.

    PubMed

    Mürdter, T E; Schroth, W; Bacchus-Gerybadze, L; Winter, S; Heinkele, G; Simon, W; Fasching, P A; Fehm, T; Eichelbaum, M; Schwab, M; Brauch, H

    2011-05-01

    The therapeutic effect of tamoxifen depends on active metabolites, e.g., cytochrome P450 2D6 (CYP2D6) mediated formation of endoxifen. To test for additional relationships, 236 breast cancer patients were genotyped for CYP2D6, CYP2C9, CYP2B6, CYP2C19, CYP3A5, UGT1A4, UGT2B7, and UGT2B15; also, plasma concentrations of tamoxifen and 22 of its metabolites, including the (E)-, (Z)-, 3-, and 4'-hydroxymetabolites as well as their glucuronides, were quantified using liquid chromatography-tandem mass spectrometry (MS). The activity levels of the metabolites were measured using an estrogen response element reporter assay; the strongest estrogen receptor inhibition was found for (Z)-endoxifen and (Z)-4-hydroxytamoxifen (inhibitory concentration 50 (IC50) 3 and 7 nmol/l, respectively). CYP2D6 genotypes explained 39 and 9% of the variability of steady-state concentrations of (Z)-endoxifen and (Z)-4-hydroxytamoxifen, respectively. Among the poor metabolizers, 93% had (Z)-endoxifen levels below IC90 values, underscoring the role of CYP2D6 deficiency in compromised tamoxifen bioactivation. For other enzymes tested, carriers of reduced-function CYP2C9 (*2, *3) alleles had lower plasma concentrations of active metabolites (P < 0.004), pointing to the role of additional pathways.

  15. Inhibitory and inductive effects of Phikud Navakot extract on human cytochrome P450.

    PubMed

    Chiangsom, Abhiruj; Lawanprasert, Somsong; Oda, Shingo; Kulthong, Kornphimol; Luechapudiporn, Rataya; Yokoi, Tsuyoshi; Maniratanachote, Rawiwan

    2016-06-01

    Effects of the hydroethanolic extract of Phikud Navakot (PN), a Thai traditional remedy, on human cytochrome P450s (CYPs) were investigated in vitro. Selective substrates of CYPs were used to investigate the effects and kinetics of PN on CYP inhibition using human liver microsomes. Primary human hepatocytes were used to assess the inductive effects of PN on CYP enzyme activities and protein expressions. The results showed that PN inhibited the activities of CYP1A2, CYP2C9, CYP2D6, and CYP3A4 with half maximal inhibitory concentration (IC50) values of 13, 62, 67, and 88 μg/mL, respectively. Meanwhile, it had no effect on the activities of CYP2C19 and CYP2E1 (IC50 > 1 mg/mL). PN exhibited competitive inhibition of CYP1A2 (Ki = 34 μg/mL), mixed type inhibition of CYP2C9 and CYP2D6 (Ki = 80 and 12 μg/mL, respectively), and uncompetitive inhibition of CYP3A4 (Ki = 150 μg/mL). PN did not have an inductive effect on CYP1A2, CYP2C9, CYP2C19 and CYP3A4 in primary human hepatocytes, which is an advantageous characteristic of the extract. However the extract may cause herb-drug interactions via inhibition of CYP1A2, CYP2C9, CYP2D6 and CYP3A4, and precautions should be taken when PN is coadministered with drugs that are metabolized by these CYP enzymes. PMID:27212065

  16. Influence of glutathione‐S‐transferase (GSTM1, GSTP1, GSTT1) and cytochrome p450 (CYP1A1, CYP2D6) polymorphisms on numbers of basal cell carcinomas (BCCs) in families with the naevoid basal cell carcinoma syndrome

    PubMed Central

    Yang, X (R); Pfeiffer, R M; Goldstein, A M

    2006-01-01

    Background The naevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant multisystem disorder with variable expression. NBCCS patients have variable susceptibility to development of basal cell carcinoma (BCC). Previous studies have shown that polymorphisms of some metabolic genes encoding the cytochrome p450 (CYP) and glutathione‐S‐transferase (GST) enzymes influenced the numbers of BCCs in sporadic BCC cases. Objective To determine whether allelic variants of these genes contribute to the variation in numbers of BCCs observed in NBCCS families. Methods Genotyping and analysis was carried out in 152 members (69 affected and 83 unaffected) of 13 families with NBCCS for seven polymorphisms in five metabolic genes including CYP1A1, CYP2D6, GSTM1, GSTP1, and GSTT1. Results GSTP1 Val105 and GSTP1 Val114 alleles were significantly associated with fewer BCC numbers (odds ratio (OR)105 = 0.55 (95% confidence interval, 0.35 to 0.88); OR114 = 0.20 (0.05 to 0.88)). The Val105 allele showed a dose dependent effect (ORIle/Val = 0.58 (0.34 to 0.88); ORVal/Val = 0.34 (0.14 to 0.78)). In addition, fewer jaw cysts were observed in carriers of the three p450 polymorphisms (CYP1A1m1, CYP1A1m2, and CYP2D6*4) (ORCYP1A1m1 = 0.27 (0.12 to 0.58); ORCYP1A1m2 = 0.25 (0.08 to 0.78); ORCYP2D6*4 = 0.33 (0.18 to 0.60)). Conclusions Genetic variants might contribute to the variation in numbers of BCCs and jaw cysts observed in NBCCS families. PMID:16582078

  17. Estimation of the binding modes with important human cytochrome P450 enzymes, drug interaction potential, pharmacokinetics, and hepatotoxicity of ginger components using molecular docking, computational, and pharmacokinetic modeling studies

    PubMed Central

    Qiu, Jia-Xuan; Zhou, Zhi-Wei; He, Zhi-Xu; Zhang, Xueji; Zhou, Shu-Feng; Zhu, Shengrong

    2015-01-01

    Ginger is one of the most commonly used herbal medicines for the treatment of numerous ailments and improvement of body functions. It may be used in combination with prescribed drugs. The coadministration of ginger with therapeutic drugs raises a concern of potential deleterious drug interactions via the modulation of the expression and/or activity of drug-metabolizing enzymes and drug transporters, resulting in unfavorable therapeutic outcomes. This study aimed to determine the molecular interactions between 12 main active ginger components (6-gingerol, 8-gingerol, 10-gingerol, 6-shogaol, 8-shogaol, 10-shogaol, ar-curcumene, β-bisabolene, β-sesquiphelandrene, 6-gingerdione, (−)-zingiberene, and methyl-6-isogingerol) and human cytochrome P450 (CYP) 1A2, 2C9, 2C19, 2D6, and 3A4 and to predict the absorption, distribution, metabolism, excretion, and toxicity (ADMET) of the 12 ginger components using computational approaches and comprehensive literature search. Docking studies showed that ginger components interacted with a panel of amino acids in the active sites of CYP1A2, 2C9, 2C19, 2D6, and 3A4 mainly through hydrogen bond formation, to a lesser extent, via π–π stacking. The pharmacokinetic simulation studies showed that the [I]/[Ki] value for CYP2C9, 2C19, and 3A4 ranged from 0.0002 to 19.6 and the R value ranged from 1.0002 to 20.6 and that ginger might exhibit a high risk of drug interaction via inhibition of the activity of human CYP2C9 and CYP3A4, but a low risk of drug interaction toward CYP2C19-mediated drug metabolism. Furthermore, it has been evaluated that the 12 ginger components possessed a favorable ADMET profiles with regard to the solubility, absorption, permeability across the blood–brain barrier, interactions with CYP2D6, hepatotoxicity, and plasma protein binding. The validation results showed that there was no remarkable effect of ginger on the metabolism of warfarin in humans, whereas concurrent use of ginger and nifedipine exhibited

  18. Estimation of the binding modes with important human cytochrome P450 enzymes, drug interaction potential, pharmacokinetics, and hepatotoxicity of ginger components using molecular docking, computational, and pharmacokinetic modeling studies.

    PubMed

    Qiu, Jia-Xuan; Zhou, Zhi-Wei; He, Zhi-Xu; Zhang, Xueji; Zhou, Shu-Feng; Zhu, Shengrong

    2015-01-01

    Ginger is one of the most commonly used herbal medicines for the treatment of numerous ailments and improvement of body functions. It may be used in combination with prescribed drugs. The coadministration of ginger with therapeutic drugs raises a concern of potential deleterious drug interactions via the modulation of the expression and/or activity of drug-metabolizing enzymes and drug transporters, resulting in unfavorable therapeutic outcomes. This study aimed to determine the molecular interactions between 12 main active ginger components (6-gingerol, 8-gingerol, 10-gingerol, 6-shogaol, 8-shogaol, 10-shogaol, ar-curcumene, β-bisabolene, β-sesquiphelandrene, 6-gingerdione, (-)-zingiberene, and methyl-6-isogingerol) and human cytochrome P450 (CYP) 1A2, 2C9, 2C19, 2D6, and 3A4 and to predict the absorption, distribution, metabolism, excretion, and toxicity (ADMET) of the 12 ginger components using computational approaches and comprehensive literature search. Docking studies showed that ginger components interacted with a panel of amino acids in the active sites of CYP1A2, 2C9, 2C19, 2D6, and 3A4 mainly through hydrogen bond formation, to a lesser extent, via π-π stacking. The pharmacokinetic simulation studies showed that the [I]/[Ki ] value for CYP2C9, 2C19, and 3A4 ranged from 0.0002 to 19.6 and the R value ranged from 1.0002 to 20.6 and that ginger might exhibit a high risk of drug interaction via inhibition of the activity of human CYP2C9 and CYP3A4, but a low risk of drug interaction toward CYP2C19-mediated drug metabolism. Furthermore, it has been evaluated that the 12 ginger components possessed a favorable ADMET profiles with regard to the solubility, absorption, permeability across the blood-brain barrier, interactions with CYP2D6, hepatotoxicity, and plasma protein binding. The validation results showed that there was no remarkable effect of ginger on the metabolism of warfarin in humans, whereas concurrent use of ginger and nifedipine exhibited a

  19. Changes in cytochrome P450s-mediated drug clearance in patients with hepatocellular carcinoma in vitro and in vivo: a bottom-up approach

    PubMed Central

    He, Xiao-Pei; Zhang, Yun-Fei; Gao, Na; Tian, Xin; Fang, Yan; Wen, Qiang; Jia, Lin-Jing; Jin, Han; Qiao, Hai-Ling

    2016-01-01

    Hepatocellular carcinoma (HCC) accompanied by severe liver dysfunction is a serious disease, which results in altered hepatic clearance. Generally, maintenance doses depend upon drug clearance, so individual dosage regimens should be customized for HCC patients based on the condition of patients. Based on clearance of CYP isoform-specific substrates at the microsomal level (CLM), microsomal protein per gram of liver (MPPGL), liver weight, hepatic blood flow, hepatic clearance values (CLH) for 10 CYPs in HCC patients (n=102) were extrapolated using a predictive bottom-up pharmacokinetic model. Compared with controls, the CLM values for CYP2C9, 2D6, 2E1 were significantly increased in HCC patients. Additionally, CYP1A2, 2C8, 2C19 CLM values decreased while the values for CYP2A6, 2B6, 3A4/5 were unchanged. The MPPGL values in HCC tissues were significantly reduced. CLH values of HCC patients for CYP1A2, 2A6, 2B6, 2C8, 2C19, and 3A4/5 were significantly reduced, while this for CYP2E1 were markedly increased and those for CYP2C9 and 2D6 did not change. Moreover, disease (fibrosis and cirrhosis) and polymorphisms of the CYP genes have influenced the CLH for some CYPs. Prediction of the effects of HCC on drug clearance may be helpful for the design of clinical studies and the clinical management of drugs in HCC patients. PMID:27086920

  20. Effect of Radix Sophorae Flavescentis on activity of CYP450 isoforms in rats

    PubMed Central

    Chen, Lianguo; Cai, Jinzhang; Wang, Shuanghu; Hu, Lufeng; Yang, Xuezhi

    2015-01-01

    Kushen (Radix Sophorae Flavescentis) is the dried roots of Sophora Flavescens Ait, alkaloids and flavonoids are the main active constituents of Radix Sophorae Flavescentis. The influence of Radix Sophorae Flavescentis on the activities of CYP450 isoforms CYP2B6, CYP2C19, CYP1A2, CYP2C9, CYP3A4 and CYP2D6 were evaluated by cocktail method. The rats were randomly divided into Radix Sophorae Flavescentis group and control group. The Radix Sophorae Flavescentis group rats were given 5 g/kg Radix Sophorae Flavescentis decoction by intragastric administration. The six probe drugs (bupropion, omeprazole, phenacetin, tolbutamide, midazolam and metroprolol) were given to rats through intragastric administration, and the plasma concentration were determined by UPLC-MS/MS. The result of Radix Sophorae Flavescentis group compared to control group, there were statistical pharmacokinetics difference for omeprazole, phenacetin, tolbutamide and metroprolol. It indicated that the Radix Sophorae Flavescentis may induce the activities of CYP2D6, and inhibit of CYP2C19, CYP1A2 and CYP2C9 of rats. As other drugs are always used after Radix Sophorae Flavescentis, interactions between other drugs and Radix Sophorae Flavescentis undertake the risk of either diminished efficacy or adverse effects. This may give advising for reasonable drug use after Radix Sophorae Flavescentis. PMID:26885078

  1. Perception of the usefulness of drug/gene pairs and barriers for pharmacogenomics in Latin America.

    PubMed

    Quinones, Luis Abel; Lavanderos, Maria Alejandra; Cayun, Juan Pablo; Garcia-Martin, Elena; Agundez, Jose Augusto; Caceres, Dante Daniel; Roco, Angela Margarita; Morales, Jorge E; Herrera, Luisa; Encina, Gonzalo; Isaza, Carlos Alberto; Redal, Maria Ana; Larovere, Laura; Soria, Nestor Walter; Eslava-Schmalbach, Javier; Castaneda-Hernandez, Gilberto; Lopez-Cortes, Andres; Magno, Luiz Alexandre; Lopez, Marisol; Chiurillo, Miguel Angel; Rodeiro, Idania; Castro de Guerra, Dinorah; Teran, Enrique; Estevez-Carrizo, Francisco; Lares-Assef, Ismael

    2014-02-01

    Pharmacogenetics and Pharmacogenomics areas are currently emerging fields focused to manage pharmacotherapy that may prevent undertreatment while avoiding associated drug toxicity in patients. Large international differences in the awareness and in the use of pharmacogenomic testing are presumed, but not well assessed to date. In the present study we review the awareness of Latin American scientific community about pharmacogenomic testing and the perceived barriers for their clinical application. In order to that, we have compiled information from 9 countries of the region using a structured survey which is compared with surveys previously performed in USA and Spain. The most relevant group of barriers was related to the need for clear guidelines for the use of pharmacogenomics in clinical practice, followed by insufficient awareness about pharmacogenomics among clinicians and the absence of regulatory institutions that facilitate the use of pharmacogenetic tests. The higher ranked pairs were TPMT/thioguanine, TPMT/azathioprine, CYP2C9/warfarin, UGT1A1/irinotecan, CYP2D6/amitriptiline, CYP2C19/citalopram and CYP2D6/clozapine. The lower ranked pairs were SLCO1B1/simvastatin, CYP2D6/metoprolol and GP6D/chloroquine. Compared with USA and Spanish surveys, 25 pairs were of lower importance for Latin American respondents. Only CYP2C19/esomeprazole, CYP2C19/omeprazole, CYP2C19/celecoxib and G6PD/dapsone were ranked higher or similarly to the USA and Spanish surveys. Integration of pharmacogenomics in clinical practice needs training of healthcare professionals and citizens, but in addition legal and regulatory guidelines and safeguards will be needed. We propose that the approach offered by pharmacogenomics should be incorporated into the decision-making plans in Latin America. PMID:24524664

  2. Perception of the usefulness of drug/gene pairs and barriers for pharmacogenomics in Latin America.

    PubMed

    Quinones, Luis Abel; Lavanderos, Maria Alejandra; Cayun, Juan Pablo; Garcia-Martin, Elena; Agundez, Jose Augusto; Caceres, Dante Daniel; Roco, Angela Margarita; Morales, Jorge E; Herrera, Luisa; Encina, Gonzalo; Isaza, Carlos Alberto; Redal, Maria Ana; Larovere, Laura; Soria, Nestor Walter; Eslava-Schmalbach, Javier; Castaneda-Hernandez, Gilberto; Lopez-Cortes, Andres; Magno, Luiz Alexandre; Lopez, Marisol; Chiurillo, Miguel Angel; Rodeiro, Idania; Castro de Guerra, Dinorah; Teran, Enrique; Estevez-Carrizo, Francisco; Lares-Assef, Ismael

    2014-02-01

    Pharmacogenetics and Pharmacogenomics areas are currently emerging fields focused to manage pharmacotherapy that may prevent undertreatment while avoiding associated drug toxicity in patients. Large international differences in the awareness and in the use of pharmacogenomic testing are presumed, but not well assessed to date. In the present study we review the awareness of Latin American scientific community about pharmacogenomic testing and the perceived barriers for their clinical application. In order to that, we have compiled information from 9 countries of the region using a structured survey which is compared with surveys previously performed in USA and Spain. The most relevant group of barriers was related to the need for clear guidelines for the use of pharmacogenomics in clinical practice, followed by insufficient awareness about pharmacogenomics among clinicians and the absence of regulatory institutions that facilitate the use of pharmacogenetic tests. The higher ranked pairs were TPMT/thioguanine, TPMT/azathioprine, CYP2C9/warfarin, UGT1A1/irinotecan, CYP2D6/amitriptiline, CYP2C19/citalopram and CYP2D6/clozapine. The lower ranked pairs were SLCO1B1/simvastatin, CYP2D6/metoprolol and GP6D/chloroquine. Compared with USA and Spanish surveys, 25 pairs were of lower importance for Latin American respondents. Only CYP2C19/esomeprazole, CYP2C19/omeprazole, CYP2C19/celecoxib and G6PD/dapsone were ranked higher or similarly to the USA and Spanish surveys. Integration of pharmacogenomics in clinical practice needs training of healthcare professionals and citizens, but in addition legal and regulatory guidelines and safeguards will be needed. We propose that the approach offered by pharmacogenomics should be incorporated into the decision-making plans in Latin America.

  3. Part I---Evaluating Effects of Oligomer Formation on Cytochrome P450 2C9 Electron Transfer and Drug Metabolism, Part II---Utilizing Molecular Modeling Techniques to Study the Src-Interacting Proteins Actin Filament Associated Protein of 110 kDa (AFAP-110) and Cortactin

    NASA Astrophysics Data System (ADS)

    Jett, John Edward, Jr.

    The dissertation has been divided into two parts to accurately reflect the two distinct areas of interest pursued during my matriculation in the School of Pharmacy at West Virginia University. In Part I, I discuss research probing the nature of electron transfer in the Cytochrome P450 family of proteins, a group of proteins well-known for their role in drug metabolism. In Part II, I focus on in silico and in vitro work developed in concert to probe protein structure and protein-protein interactions involved in actin filament reorganization and cellular motility. Part I. Cytochrome P450s (P450s) are an important class of enzymes known to metabolize a variety of endogenous and xenobiotic compounds. P450s are most commonly found in liver and intestinal endothelial cells and are responsible for the metabolism of approximately 75% of pharmaceutical drugs on the market. CYP2C9---one of the six major P450 isoforms---is responsible for ˜20% of drug metabolism. Elucidation of the factors that affect in vitro drug metabolism is crucial to the accurate prediction of in vivo drug metabolism kinetics. Currently, the two major techniques for studying in vitro drug metabolism are solution-based. However, it is known that the results of solution-based studies can vary from in vivo drug metabolism. One reason suggested to account for this variation is the state of P450 oligomer formation in solution compared to the in vivo environment, where P450s are membrane-bound. To understand the details of how oligomer formation affects in vitro drug metabolism, it is imperative that techniques be developed which will allow for the unequivocal control of oligomer formation without altering other experimental parameters. Our long term goal of this research is to develop methods to more accurately predict in vivo drug metabolism from in vitro data. This section of the dissertation will discuss the development of a platform consisting of a doped silicon surface containing a large array of gold

  4. In vitro inhibitory effects of scutellarin on six human/rat cytochrome P450 enzymes and P-glycoprotein.

    PubMed

    Han, Yong-Long; Li, Dan; Yang, Quan-Jun; Zhou, Zhi-Yong; Liu, Li-Ya; Li, Bin; Lu, Jin; Guo, Cheng

    2014-05-05

    Inhibition of cytochrome P450 (CYP) and P-glycoprotein (P-gp) are regarded as the most frequent and clinically important pharmacokinetic causes among the various possible factors for drug-drug interactions. Scutellarin is a flavonoid which is widely used for the treatment of cardiovascular diseases. In this study, the in vitro inhibitory effects of scutellarin on six major human CYPs (CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A4) and six rat CYPs (CYP1A2, CYP2C7, CYP2C11, CYP2C79, CYP2D4, and CYP3A2) activities were examined by using liquid chromatography-tandem mass spectrometry. Meanwhile, the inhibitory effects of scutellarin on P-gp activity were examined on a human metastatic malignant melanoma cell line WM-266-4 by calcein-AM fluorometry screening assay. Results demonstrated that scutellarin showed negligible inhibitory effects on the six major CYP isoenzymes in human/rat liver microsomes with almost all of the IC50 values exceeding 100 μM, whereas it showed values of 63.8 μM for CYP2C19 in human liver microsomes, and 63.1 and 85.6 μM for CYP2C7 and CYP2C79 in rat liver microsomes, respectively. Scutellarin also showed weak inhibitory effect on P-gp. In conclusion, this study demonstrates that scutellarin is unlikely to cause any clinically significant herb-drug interactions in humans when co-administered with substrates of the six CYPs (CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A4) and P-gp.

  5. Xenobiotic Sensor- and Metabolism-Related Gene Variants in Environmental Sensitivity-Related Illnesses: A Survey on the Italian Population

    PubMed Central

    Caccamo, Daniela; Cesareo, Eleonora; Mariani, Serena; Raskovic, Desanka; Ientile, Riccardo; Currò, Monica; Korkina, Liudmila; De Luca, Chiara

    2013-01-01

    In the environmental sensitivity-related illnesses (SRIs), multiple chemical sensitivity (MCS), chronic fatigue syndrome (FCS), and fibromyalgia (FM), the search for genetic polymorphisms of phase I/II xenobiotic-metabolizing enzymes as suitable diagnostic biomarkers produced so far inconclusive results, due to patient heterogeneity, geographic/ethnic differences in genetic backgrounds, and different methodological approaches. Here, we compared the frequency of gene polymorphisms of selected cytochrome P450 (CYP) metabolizing enzymes and, for the first time, the frequency of the xenobiotic sensor Aryl hydrocarbon receptor (AHR) in the three cohorts of 156 diagnosed MCS, 94 suspected MCS, and 80 FM/FCS patients versus 113 healthy controls. We found significantly higher frequency of polymorphisms CYP2C9∗2, CYP2C9∗3, CYP2C19∗2, CYP2D6∗4 and CYP2D6∗41 in patients compared with controls. This confirms that these genetic variants represent a genetic risk factor for SRI. Moreover, the compound heterozygosity for CYP2C9∗2 and ∗3 variants was useful to discriminate between either MCS or FM/CFS versus SMCS, while the PM ∗41/∗41 genotype discriminated between MCS and either SMCS or FM/CFS. The compound heterozygosity for CYP2C9 ∗1/∗3 and CYP2D6 ∗1/∗4 differentiated MCS and SMCS cases from FM/CFS ones. Interestingly, despite the distribution of the AHR Arg554Lys variant did not result significantly different between SRI cases and controls, it resulted useful for the discrimination between MCS and SMCS cases when considered within haplotypes in combination with CYP2C19 ∗1/∗2 and CYP2D6 ∗1/∗4. Results allowed us to propose the genotyping for these specific CYP variants, together with the AHR Arg554Lys variant, as reliable, cost-effective genetic parameters to be included in the still undefined biomarkers' panel for laboratory diagnosis of the main types of environmental-borne SRI. PMID:23936614

  6. In vitro oxidative metabolism of cajaninstilbene Acid by human liver microsomes and hepatocytes: involvement of cytochrome p450 reaction phenotyping, inhibition, and induction studies.

    PubMed

    Hua, Xin; Peng, Xiao; Tan, Shengnan; Li, Chunying; Wang, Wei; Luo, Meng; Fu, Yujie; Zu, Yuangang; Smyth, Hugh

    2014-10-29

    Cajaninstilbene acid (CSA, 3-hydroxy-4-prenyl-5-methoxystilbene-2-carboxylic acid), an active constituent of pigeonpea leaves, an important tropical crop, is known for its clinical effects in the treatment of diabetes, hepatitis, and measles and its potential antitumor effect. In this study, the effect of the cytochrome P450 isozymes on the activity of CSA was investigated. Two hydroxylation metabolites were identified in the study. The reaction phenotype study showed that CYP3A4, CYP2C9, and CYP1A2 were the major cytochrome P450 isozymes in the metabolism of CSA. The metabolic food-drug interaction potential was also evaluated in vitro. The effect of CSA inhibition/induction of enzymatic activities of seven drug-metabolizing CYP450 isozymes in vitro was estimated by high-performance liquid chromatography and liquid chromatography-tandem mass spectrometry analytical techniques. CSA showed different inhibitory effects on different isozymes. CSA reversibly inhibited CYP3A4 and CYP2C9 activities in human liver microsomes with IC50 values of 28.3 and 31.3 μM, respectively, but exhibited no inhibition activities to CYP1A2, CYP2A6, CYP2C19, CYP2D6, and CYP2E1. CSA showed a weak effect on CYP450 enzymes in a time-dependent manner. CSA did not substantially induce CYP1A2, CYP2A6, CYP2B6, CYP2E1, CYP2C9, CYP2C19, CYP2D6, or CYP3A4 at concentrations up to 30 μM in primary human hepatocytes. The results of our experiments may be helpful to predict clinically significant food-drug interactions when other drugs are administered in combination with CSA. PMID:25272989

  7. Simultaneous determination of bupropion, metroprolol, midazolam, phenacetin, omeprazole and tolbutamide in rat plasma by UPLC-MS/MS and its application to cytochrome P450 activity study in rats.

    PubMed

    Ma, Jianshe; Wang, Shuanghu; Zhang, Meiling; Zhang, Qingwei; Zhou, Yunfang; Lin, Chongliang; Lin, Guanyang; Wang, Xianqin

    2015-08-01

    A specific ultra-performance liquid chromatography tandem mass spectrometry method is described for the simultaneous determination of bupropion, metroprolol, midazolam, phenacetin, omeprazole and tolbutamide in rat plasma with diazepam as internal standard, which are the six probe drugs of the six cytochrome P450 isoforms CYP2B6, CYP2D6, CYP3A4, CYP1A2, CYP2C19 and CYP2C9. Plasma samples were protein precipitated with acetonitrile. The chromatographic separation was achieved using a UPLC® BEH C18 column (2.1 × 100 mm, 1.7 µm). The mobile phase consisted of acetonitrile and water (containing 0.1% formic acid) with gradient elution. The triple quadrupole mass spectrometric detection was operated by multiple reaction monitoring in positive electrospray ionization. The precisions were <13%, and the accuracy ranged from 93.3 to 110.4%. The extraction efficiency was >90.5%, and the matrix effects ranged from 84.3 to 114.2%. The calibration curves in plasma were linear in the range of 2-2000 ng/mL, with correlation coefficient (r(2) ) >0.995. The method was successfully applied to pharmacokinetic studies of the six probe drugs of the six CYP450 isoforms and used to evaluate the effects of erlotinib on the activities of CYP2B6, CYP2D6, CYP3A4, CYP1A2, CYP2C19 and CYP2C9 in rats. Erlotinib may inhibit the activity of CYP2B6 and CYP3A4, and may induce CYP2C9 of rats.

  8. Evaluation of the impact of Flos Daturae on rat hepatic cytochrome P450 enzymes by cocktail probe drugs.

    PubMed

    Geng, Peiwu; Wang, Shuanghu; Wang, Chunjie; Chen, Jianmiao; Zhang, Lijing; Yang, Suping; Wen, Congcong; Zhou, Yunfang; Zhang, Meiling

    2015-01-01

    Flos Daturae, known as "baimantuoluo" or "yangjinhua" in China, has been used for centuries in Traditional Chinese Medicine for the treatment of asthma, convulsions, pain, and rheumatism. To investigate the influences of Flos Daturae on the activities of rat CYP450 enzymes (CYP1A2, CYP2C9, CYP2C19, CYP2B6, CYP2D6 and CYP3A4) using cocktail probe drugs in vivo. A cocktail solution at a dose of 5 mL/kg, which contained phenacetin (10 mg/kg), tolbutamide (1 mg/kg), omeprazole (10 mg/kg), bupropion (10 mg/kg), metoprolol (10 mg/kg) and testosterone (10 mg/kg), was intragastric administered to rats treated with a single low or high dose of Flos Daturae decotion for 7days. Blood samples collected at a series of time-points in plasma were determined by UPLC-MS/MS. The corresponding pharmacokinetic parameters were calculated by the software of DAS 3.0. The results from the present in vivo study showed that Flos Daturae induce the activity of CYP2D6 enzyme with the decreased Cmax, AUC(0-∞) (P < 0.05) and the increased CL (P < 0.05). However, there were no significant differences of other probe drugs in plasma concentration and pharmacokinetic parameters. There were no significant effects on rat CYP1A2, CYP3A4, CYP2B6, CYP2C9 and CYP2C19 by Flos Daturae. Therefore, the resulting data suggested that caution was needed when Flos Daturae was co-administered with CYP2D6 substrates, which may result in treatment failure and herb-drug interactions. PMID:26885208

  9. Inhibition of human cytochrome P450 enzymes by Bacopa monnieri standardized extract and constituents.

    PubMed

    Ramasamy, Seetha; Kiew, Lik Voon; Chung, Lip Yong

    2014-02-24

    Bacopa monnieri and the constituents of this plant, especially bacosides, possess various neuropharmacological properties. Like drugs, some herbal extracts and the constituents of their extracts alter cytochrome P450 (CYP) enzymes, causing potential herb-drug interactions. The effects of Bacopa monnieri standardized extract and the bacosides from the extract on five major CYP isoforms in vitro were analyzed using a luminescent CYP recombinant human enzyme assay. B. monnieri extract exhibited non-competitive inhibition of CYP2C19 (IC50/Ki = 23.67/9.5 µg/mL), CYP2C9 (36.49/12.5 µg/mL), CYP1A2 (52.20/25.1 µg/mL); competitive inhibition of CYP3A4 (83.95/14.5 µg/mL) and weak inhibition of CYP2D6 (IC50 = 2061.50 µg/mL). However, the bacosides showed negligible inhibition of the same isoforms. B. monnieri, which is orally administered, has a higher concentration in the gut than the liver; therefore, this herb could exhibit stronger inhibition of intestinal CYPs than hepatic CYPs. At an estimated gut concentration of 600 µg/mL (based on a daily dosage of 300 mg/day), B. monnieri reduced the catalytic activities of CYP3A4, CYP2C9 and CYP2C19 to less than 10% compared to the total activity (without inhibitor = 100%). These findings suggest that B. monnieri extract could contribute to herb-drug interactions when orally co-administered with drugs metabolized by CYP1A2, CYP3A4, CYP2C9 and CYP2C19.

  10. Ellipticine oxidation and DNA adduct formation in human hepatocytes is catalyzed by human cytochromes P450 and enhanced by cytochrome b5.

    PubMed

    Stiborová, Marie; Poljaková, Jitka; Martínková, Eva; Ulrichová, Jitka; Simánek, Vilím; Dvořák, Zdeněk; Frei, Eva

    2012-12-16

    Ellipticine is an antineoplastic agent considered a pro-drug, the pharmacological and genotoxic effects of which are dependent on cytochrome P450 (CYP)- and/or peroxidase-mediated activation to covalent DNA adducts. We investigated whether ellipticine-DNA adducts are formed in human hepatic microsomes and human hepatocytes. We then identified which human CYPs oxidize ellipticine to metabolites forming DNA adducts and the effect of cytochrome b(5) on this oxidation. 13-Hydroxyellipticine, the metabolite forming the major ellipticine-DNA adduct, was generated mainly by CYP3A4 and 1A1, followed by CYP2D6>2C19>1B1>1A2>2E1 and >2C9. Cytochrome b(5) increased formation of this metabolite by human CYPs, predominantly by CYP1A1, 3A4, 1A2 and 2C19. Formation of 12-hydroxyellipticine is generated mainly by CYP2C19, followed by CYP2C9>3A4>2D6>2E1 and >2A6. Other CYPs were less active (CYP2C8 and 2B6) or did not oxidize ellipticine to this metabolite (CYP1A1, 1A2 and 1B1). CYP2D6 was the most efficient enzyme generating ellipticine N(2)-oxide. CYP3A4 and 1A1 in the presence of cytochrome b(5) are mainly responsible for bioactivation of ellipticine to DNA adduct 1 (formed by ellipticine-13-ylium from 13-hydroxyellipticine), while 12-hydroxyellipticine generated during the CYP2C19-mediated ellipticine oxidation is the predominant metabolite forming ellipticine-12-ylium that generates ellipticine-DNA adduct 2. These ellipticine-DNA adducts were also generated by human hepatic microsomes and in primary human hepatocytes exposed to ellipticine. Ellipticine is toxic to these hepatocytes, decreasing their viability; the IC(50) value of ellipticine in these cells was 0.7 μM. In liver CYP3A4 is the predominant ellipticine activating CYP species, which is expected to result in efficient metabolism after oral ingestion of ellipticine in humans.

  11. Complex Hydrocarbon Chemistry in Interstellar and Solar System Ices Revealed: A Combined Infrared Spectroscopy and Reflectron Time-of-flight Mass Spectrometry Analysis of Ethane (C2H6) and D6-Ethane (C2D6) Ices Exposed to Ionizing Radiation

    NASA Astrophysics Data System (ADS)

    Abplanalp, Matthew J.; Kaiser, Ralf I.

    2016-08-01

    The irradiation of pure ethane (C2H6/C2D6) ices at 5.5 K, under ultrahigh vacuum conditions was conducted to investigate the formation of complex hydrocarbons via interaction with energetic electrons simulating the secondary electrons produced in the track of galactic cosmic rays. The chemical modifications of the ices were monitored in situ using Fourier transform infrared spectroscopy (FTIR) and during temperature-programmed desorption via mass spectrometry exploiting a quadrupole mass spectrometer with electron impact ionization (EI-QMS) as well as a reflectron time-of-flight mass spectrometer coupled to a photoionization source (PI-ReTOF-MS). FTIR confirmed previous ethane studies by detecting six molecules: methane (CH4), acetylene (C2H2), ethylene (C2H4), the ethyl radical (C2H5), 1-butene (C4H8), and n-butane (C4H10). However, the TPD phase, along with EI-QMS, and most importantly, PI-ReTOF-MS, revealed the formation of at least 23 hydrocarbons, many for the first time in ethane ice, which can be arranged in four groups with an increasing carbon-to-hydrogen ratio: C n H2n+2 (n = 3, 4, 6, 8, 10), C n H2n (n = 3–10), {{{C}}}n{{{H}}}2n-2 (n = 3–10), and {{{C}}}n{{{H}}}2n-4 (n = 4–6). The processing of simple ethane ices is relevant to the hydrocarbon chemistry in the interstellar medium, as ethane has been shown to be a major product of methane, as well as in the outer solar system. These data reveal that the processing of ethane ices can synthesize several key hydrocarbons such as C3H4 and C4H6 isomers, which ha­ve been found to synthesize polycyclic aromatic hydrocarbons like indene (C9H8) and naphtha­lene (C10H8) in the ISM and in hydrocarbon-rich atmospheres of planets and their moons such as Titan.

  12. Complex Hydrocarbon Chemistry in Interstellar and Solar System Ices Revealed: A Combined Infrared Spectroscopy and Reflectron Time-of-flight Mass Spectrometry Analysis of Ethane (C2H6) and D6-Ethane (C2D6) Ices Exposed to Ionizing Radiation

    NASA Astrophysics Data System (ADS)

    Abplanalp, Matthew J.; Kaiser, Ralf I.

    2016-08-01

    The irradiation of pure ethane (C2H6/C2D6) ices at 5.5 K, under ultrahigh vacuum conditions was conducted to investigate the formation of complex hydrocarbons via interaction with energetic electrons simulating the secondary electrons produced in the track of galactic cosmic rays. The chemical modifications of the ices were monitored in situ using Fourier transform infrared spectroscopy (FTIR) and during temperature-programmed desorption via mass spectrometry exploiting a quadrupole mass spectrometer with electron impact ionization (EI-QMS) as well as a reflectron time-of-flight mass spectrometer coupled to a photoionization source (PI-ReTOF-MS). FTIR confirmed previous ethane studies by detecting six molecules: methane (CH4), acetylene (C2H2), ethylene (C2H4), the ethyl radical (C2H5), 1-butene (C4H8), and n-butane (C4H10). However, the TPD phase, along with EI-QMS, and most importantly, PI-ReTOF-MS, revealed the formation of at least 23 hydrocarbons, many for the first time in ethane ice, which can be arranged in four groups with an increasing carbon-to-hydrogen ratio: C n H2n+2 (n = 3, 4, 6, 8, 10), C n H2n (n = 3-10), {{{C}}}n{{{H}}}2n-2 (n = 3-10), and {{{C}}}n{{{H}}}2n-4 (n = 4-6). The processing of simple ethane ices is relevant to the hydrocarbon chemistry in the interstellar medium, as ethane has been shown to be a major product of methane, as well as in the outer solar system. These data reveal that the processing of ethane ices can synthesize several key hydrocarbons such as C3H4 and C4H6 isomers, which ha­ve been found to synthesize polycyclic aromatic hydrocarbons like indene (C9H8) and naphtha­lene (C10H8) in the ISM and in hydrocarbon-rich atmospheres of planets and their moons such as Titan.

  13. Involvement of multiple cytochrome P450 and UDP-glucuronosyltransferase enzymes in the in vitro metabolism of muraglitazar.

    PubMed

    Zhang, Donglu; Wang, Lifei; Chandrasena, Gamini; Ma, Li; Zhu, Mingshe; Zhang, Hongjian; Davis, Carl D; Humphreys, W Griffith

    2007-01-01

    Muraglitazar (Pargluva), a dual alpha/gamma peroxisome proliferator-activated receptor activator, has both glucose- and lipid-lowering effects in animal models and in patients with diabetes. The human major primary metabolic pathways of muraglitazar include acylglucuronidation, aliphatic/aryl hydroxylation, and O-demethylation. This study describes the identification of human cytochrome P450 (P450) and UDP-glucuronosyltransferase (UGT) enzymes involved in the in vitro metabolism of muraglitazar. [(14)C]Muraglitazar was metabolized by cDNA-expressed CYP2C8, 2C9, 2C19, 2D6, and 3A4, but to a very minimal extent by CYP1A2, 2A6, 2B6, 2C18, 2E1, and 3A5. Inhibition of the in vitro metabolism of muraglitazar in human liver microsomes, at a clinically efficacious concentration, by chemical inhibitors and monoclonal antibodies further supported involvement of CYP2C8, 2C9, 2C19, 2D6, and 3A4 in its oxidation. A combination of intrinsic clearance (V(max)/K(m)) and relative concentrations of each P450 enzyme in the human liver was used to predict the contribution of CYP2C8, 2C9, 2C19, 2D6, and 3A4 to the formation of each primary oxidative metabolite and to the overall oxidative metabolism of muraglitazar. Glucuronidation of [(14)C]muraglitazar was catalyzed by cDNA-expressed UGT1A1, 1A3, and 1A9, but not by UGT1A6, 1A8, 1A10, 2B4, 2B7, and 2B15. The K(m) values for muraglitazar glucuronidation by the three active UGT enzymes were similar (2-4 muM). In summary, muraglitazar was metabolized by multiple P450 and UGT enzymes to form multiple metabolites. This characteristic predicts a low potential for the alteration of the pharmacokinetic parameters of muraglitazar via polymorphic drug metabolism enzymes responsible for clearance of the compound or by coadministration of drugs that inhibit or induce relevant metabolic enzymes. PMID:17062778

  14. Effects of suberoylanilide hydroxamic acid on rat cytochrome P450 enzyme activities.

    PubMed

    Lin, Kezhi; Zhang, Qingwei; Liu, Zezheng; Yang, Suping; Lin, Yingying; Wen, Congcong; Zheng, Yuancai

    2015-01-01

    Vorinostat (suberoylanilide hydroxamic acid, SAHA) is the first approved histone deacetylase (HDAC) inhibitor for the treatment of cutaneous T-cell lymphoma after progressive disease following two systemic therapies. The rats were randomly divided into SAHA groups (low, medium and high dosage) and control group. The SAHA group rats were given 12.3, 24.5, and 49 mg/kg SAHA, respectively, by continuous intragastric administration for 7 days. The influence of SAHA on the activities of CYP450 isoforms CYP2B6, CYP1A2, CYP2C19, CYP2D6 and CYP2C9 were evaluated by cocktail method, they were responsed by the changes of pharmacokinetic parameters of bupropion, phenacetin, tolbutamide, metroprolol and omeprazole. The five probe drugs were given to rats through intragastric administration, and the plasma concentration were determined by UPLC-MS/MS. The result of SAHA group compared to control group, there were statistical pharmacokinetics difference for bupropion, phenacetin, tolbutamide and metroprolol. Continuous intragastric administration for 7 days may induce the activities of CYP2C19 of rats, inhibit CYP1A2 and slightly inhibit CYP2B6 and CYP2D6 of rats. This may give advising for reasonable drug use after co-used with SAHA. The results indicated that drug co-administrated with SAHA may need dose adjustment. Furthermore, continuous intragastric administration of SAHA for 7 days, liver cell damaged, causing liver cell edema, in liver metabolism process.

  15. Inhibitory effects of kale ingestion on metabolism by cytochrome P450 enzymes in rats.

    PubMed

    Yamasaki, Izumi; Yamada, Masayoshi; Uotsu, Nobuo; Teramoto, Sachiyuki; Takayanagi, Risa; Yamada, Yasuhiko

    2012-01-01

    Kale (Brassica oleracea L. var acephala DC) is a leafy green vegetable belonging to the cabbage family (Brassicaceae) that contains a large amount of health-promoting phytochemicals. There are any reports about the effects of kale ingestion on the chemoprevention function and mechanism, but the interactions between kale and drugs have not been researched. We investigated the effects of kale intake on cytochrome P450 (CYP) metabolism by using cocktail probe drugs, including midazolam (for CYP3A4), caffeine (for CYP1A2), dextromethorphan (for CYP2D6), tolbutamide (for CYP2C9), omeprazole (for CYP2C19), and chlorzoxazone (for CYP2E1). Cocktail drugs were administered into rats treated with kale and cabbage (2000 mg/kg) for a week. The results showed that kale intake induced a significant increase in plasma levels and the AUC of midazolam, caffeine, and dextromethorphan. In addition, the plasma concentration and AUC of omeprazole tended to increase. Additionally, no almost differences in the mRNA expression levels of CYP enzymes in the liver were observed. In conclusion, kale ingestion was considered to have an inhibitory effect on the activities of CYP3A4, 1A2, 2D6, and 2C19 for a reason competitive inhibition than inhibitory changes in the mRNA expressions.

  16. ADMET rules of thumb II: A comparison of the effects of common substituents on a range of ADMET parameters.

    PubMed

    Gleeson, Paul; Bravi, Gianpaolo; Modi, Sandeep; Lowe, Daniel

    2009-08-15

    A systematic analysis of data generated in key in vitro assays within GSK has been undertaken to identify what impact a range of common substituents have on a range of ADMET parameters. These include; P450 1A2, 2C9, 2C19, 2D6 and 3A4 inhibition, hERG inhibition, phosphate buffer solubility and artificial membrane permeability. We do this by identifying all matched molecular pairs, differing by the replacement of a hydrogen atom with a list of predefined substituents. For each substituent we calculate the mean difference in the ADMET parameter for all the matched molecular pairs identified, making a statistical assessment of the difference, as well as assessing the diversity for each example to ensure that the results can be generalized. We also relate the change in activity observed for each substituent to differences in their molecular properties in an effort to identify any structural alerts. PMID:19632124

  17. Practical recommendations for pharmacogenomics-based prescription: 2010 ESF-UB Conference on Pharmacogenetics and Pharmacogenomics.

    PubMed

    Becquemont, Laurent; Alfirevic, Ana; Amstutz, Ursula; Brauch, Hiltrud; Jacqz-Aigrain, Evelyne; Laurent-Puig, Pierre; Molina, Miguel A; Niemi, Mikko; Schwab, Matthias; Somogyi, Andrew A; Thervet, Eric; Maitland-van der Zee, Anke-Hilse; van Kuilenburg, André Bp; van Schaik, Ron Hn; Verstuyft, Céline; Wadelius, Mia; Daly, Ann K

    2011-01-01

    The present article summarizes the discussions of the 3rd European Science Foundation-University of Barcelona (ESF-UB) Conference in Biomedicine on Pharmacogenetics and Pharmacogenomics, which was held in June 2010 in Spain. It was focused on practical applications in routine medical practice. We provide practical recommendations for ten different clinical situations, that have either been approved or not approved by regulatory agencies. We propose some comments that might accompany the results of these tests, indicating the best drug and doses to be prescribed. The discussed examples include KRAS, cetuximab, panitumumab, EGFR-gefitinib, CYP2D6-tamoxifen, TPMT-azathioprine-6-mercaptopurine, VKORC1/CYP2C9-warfarin, CYP2C19-clopidogrel, HLA-B*5701-abacavir, HLA-B*5701-flucloxacillin, SLCO1B1-statins and CYP3A5-tacrolimus. We hope that these practical recommendations will help physicians, biologists, scientists and other healthcare professionals to prescribe, perform and interpret these genetic tests.

  18. ADMET rules of thumb II: A comparison of the effects of common substituents on a range of ADMET parameters.

    PubMed

    Gleeson, Paul; Bravi, Gianpaolo; Modi, Sandeep; Lowe, Daniel

    2009-08-15

    A systematic analysis of data generated in key in vitro assays within GSK has been undertaken to identify what impact a range of common substituents have on a range of ADMET parameters. These include; P450 1A2, 2C9, 2C19, 2D6 and 3A4 inhibition, hERG inhibition, phosphate buffer solubility and artificial membrane permeability. We do this by identifying all matched molecular pairs, differing by the replacement of a hydrogen atom with a list of predefined substituents. For each substituent we calculate the mean difference in the ADMET parameter for all the matched molecular pairs identified, making a statistical assessment of the difference, as well as assessing the diversity for each example to ensure that the results can be generalized. We also relate the change in activity observed for each substituent to differences in their molecular properties in an effort to identify any structural alerts.

  19. Short-term fasting alters cytochrome P450-mediated drug metabolism in humans.

    PubMed

    Lammers, Laureen A; Achterbergh, Roos; de Vries, Emmely M; van Nierop, F Samuel; Klümpen, Heinz-Josef; Soeters, Maarten R; Boelen, Anita; Romijn, Johannes A; Mathôt, Ron A A

    2015-06-01

    Experimental studies indicate that short-term fasting alters drug metabolism. However, the effects of short-term fasting on drug metabolism in humans need further investigation. Therefore, the aim of this study was to evaluate the effects of short-term fasting (36 h) on P450-mediated drug metabolism. In a randomized crossover study design, nine healthy subjects ingested a cocktail consisting of five P450-specific probe drugs [caffeine (CYP1A2), S-warfarin (CYP2C9), omeprazole (CYP2C19), metoprolol (CYP2D6), and midazolam (CYP3A4)] on two occasions (control study after an overnight fast and after 36 h of fasting). Blood samples were drawn for pharmacokinetic analysis using nonlinear mixed effects modeling. In addition, we studied in Wistar rats the effects of short-term fasting on hepatic mRNA expression of P450 isoforms corresponding with the five studied P450 enzymes in humans. In the healthy subjects, short-term fasting increased oral caffeine clearance by 20% (P = 0.03) and decreased oral S-warfarin clearance by 25% (P < 0.001). In rats, short-term fasting increased mRNA expression of the orthologs of human CYP1A2, CYP2C19, CYP2D6, and CYP3A4 (P < 0.05), and decreased the mRNA expression of the ortholog of CYP2C9 (P < 0.001) compared with the postabsorptive state. These results demonstrate that short-term fasting alters cytochrome P450-mediated drug metabolism in a nonuniform pattern. Therefore, short-term fasting is another factor affecting cytochrome P450-mediated drug metabolism in humans.

  20. Prediction of Cytochrome P450 Profiles of Environmental Chemicals with QSAR Models Built from Drug-like Molecules

    PubMed Central

    Sun, Hongmao; Veith, Henrike; Xia, Menghang; Austin, Christopher P.; Tice, Raymond R.; Huang, Ruili

    2012-01-01

    The human cytochrome P450 (CYP) enzyme family is involved in the biotransformation of many xenobiotics. As part of the U.S. Tox21 Phase I effort, we profiled the CYP activity of approximately three thousand compounds, primarily those of environmental concern, against human CYP1A2, CYP2C19, CYP2C9, CYP2D6, and CYP3A4 isoforms in a quantitative high throughput screening (qHTS) format. In order to evaluate the extent to which computational models built from a drug-like library screened in these five CYP assays under the same conditions can accurately predict the outcome of an environmental compound library, five support vector machines (SVM) models built from over 17,000 drug-like compounds were challenged to predict the CYP activities of the Tox21 compound collection. Although a large fraction of the test compounds fall outside of the applicability domain (AD) of the models, as measured by k-nearest neighbor (k-NN) similarities, the predictions were largely accurate for CYP1A2, CYP2C9, and CYP3A4 ioszymes with area under the receiver operator characteristic curves (AUC-ROC) ranging between 0.82 and 0.84. The lower predictive power of the CYP2C19 model (AUC-ROC = 0.76) is caused by experimental errors and that of the CYP2D6 model (AUC-ROC = 0.76) can be rescued by rebalancing the training data. Our results demonstrate that decomposing molecules into atom types enhanced the coverage of the AD and that computational models built from drug-like molecules can be used to predict the ability of non-drug like compounds to interact with these CYPs. PMID:23459712

  1. Modulation of CYPs, P-gp, and PXR by Eschscholzia californica (California Poppy) and Its Alkaloids.

    PubMed

    Manda, Vamshi K; Ibrahim, Mohamed A; Dale, Olivia R; Kumarihamy, Mallika; Cutler, Stephen J; Khan, Ikhlas A; Walker, Larry A; Muhammad, Ilias; Khan, Shabana I

    2016-04-01

    Eschscholzia californica, a native US plant, is traditionally used as a sedative, analgesic, and anxiolytic herb. With the rapid rise in the use of herbal supplements together with over-the-counter and prescription drugs, the risk for potential herb-drug interactions is also increasing. Most of the clinically relevant pharmacokinetic drug interactions occur due to modulation of cytochrome P450 enzymes (CYPs), P-glycoprotein, and the pregnane X receptor by concomitantly used herbs. This study aimed to determine the effects of an EtOH extract, aqueous extract (tea), basic CHCl3 fractions, and isolated major alkaloids, namely protopine (1), escholtzine (2), allocryptopine (3), and californidine (4), of E. californica on the activity of cytochrome P450s, P-glycoprotein and the pregnane X receptor. The EtOH extract and fractions showed strong time-dependent inhibition of CYP 3A4, CYP 2C9, and CYP 2C19, and reversible inhibition of CYP 2D6. Among the alkaloids, escholtzine (2) and allocryptopine (3) exhibited time-dependent inhibition of CYP 3A4, CYP 2C9, and CYP 2C19 (IC50 shift ratio > 2), while protopine (1) and allocryptopine (3) showed reversible inhibition of CYP 2D6 enzyme. A significant activation of the pregnane X receptor (> 2-fold) was observed with the EtOH extract, basic CHCl3 fraction, and alkaloids (except protopine), which resulted into an increased expression of mRNA and the activity of CYP 3A4 and CYP 1A2. The expression of P-glycoprotein was unaffected. However, aqueous extract (tea) and its main alkaloid californidine (4) did not affect cytochrome P450s, P-glycoprotein, or the pregnane X receptor. This data suggests that EtOH extract of E. californica and its major alkaloids have a potential of causing interactions with drugs that are metabolized by cytochrome P450s, while the tea seems to be safer. PMID:27054913

  2. Zolpidem metabolism in vitro: responsible cytochromes, chemical inhibitors, and in vivo correlations

    PubMed Central

    von Moltke, Lisa L; Greenblatt, David J; Granda, Brian W; Duan, Su Xiang; Grassi, Jeffrey M; Venkatakrishnan, Karthik; Harmatz, Jerold S; Shader, Richard I

    1999-01-01

    Aims To determine the human cytochromes mediating biotransformation of the imidazopyridine hypnotic, zolpidem, and the clinical correlates of the findings. Methods Kinetic properties of zolpidem biotransformation to its three hydroxylated metabolites were studied in vitro using human liver microsomes and heterologously expressed individual human cytochromes. Results The metabolic product termed M-3 accounted for more than 80% of net intrinsic clearance by liver microsomes in vitro. Microsomes containing human cytochromes CYP1A2, 2C9, 2C19, 2D6, and 3 A4 expressed by cDNA-transfected human lymphoblastoid cells mediated zolpidem metabolism in vitro. The kinetic profile for zolpidem metabolite formation by each individual cytochrome was combined with estimated relative abundances based on immunological quantification, yielding projected contributions to net intrinsic clearance of: 61% for 3 A4, 22% for 2C9, 14% for 1A2, and less than 3% for 2D6 and 2C19. These values were consistent with inhibitory effects of ketoconazole and sulfaphenazole on zolpidem biotransformation by liver microsomes. Ketoconazole had a 50% inhibitory concentration (IC50) of 0.61 μm vs formation of the M-3 metabolite of zolpidem in vitro; in a clinical study, ketoconazole coadministration reduced zolpidem oral clearance by ≈40%, somewhat less than anticipated based on the IC50 value and total plasma ketoconazole levels, but much more than predicted based on unbound plasma ketoconazole levels. Conclusions The incomplete dependence of zolpidem clearance on CYP3A activity has clinical implications for susceptibility to metabolic inhibition. PMID:10383565

  3. Assessment of a dry extract from milk thistle (Silybum marianum) for interference with human liver cytochrome-P450 activities.

    PubMed

    Doehmer, Johannes; Weiss, Gabriele; McGregor, Gerard P; Appel, Kurt

    2011-02-01

    The effect of a standardised dry extract from Silybum marianum (HEPAR-PASC®) on the enzyme kinetics of cytochrome-P450 isoenzymes (CYP) was investigated with primary human hepatocytes and human liver microsomes in order to assess the potential for drug-drug interactions. A cytotoxic effect on hepatocytes was observed at concentrations at and above 50 μg/ml. The EC(50) value was calculated to be 72.0 μg/ml. Therefore, the chosen test concentrations for CYP induction on human hepatocytes were 50, 10, and 1.5 μg/ml, which allowed for interpretation of the clinical significance of the data with a range of 50-1-fold c(max) at maximal recommended doses. No induction was observed at the lowest concentration of 1.5 μg/ml, which is close to c(max). The extract did not induce CYP 3A4 at any of the tested concentrations. A low or marginal induction of 1A2, 2B6, and 2E1 at the maximum concentration of 50 μg/ml was observed. CYP inhibition on human microsomes was tested at concentrations of 150, 15, and 1.5 μg/ml. No or minor CYP inhibition was observed for all CYPs tested at the lowest concentration of 1.5 μg/ml, i.e. CYPs 1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, and 3A4. At concentrations of 15 and 150 μg/ml the extract significantly inhibited CYP 2B6, 2C8, 2C9, 2C19, 2E1, and 3A4. In these cases, K(i) values were determined. All K(i) values exceeded c(max) by at least a factor of 10-fold. According to FDA regulations 1>c(max)/K(i)>0.1 indicates, that drug-drug interactions are possible for CYPs 2C8, and 2C9, but not likely, and are remote for CYPs 2C19, 2D6, and 3A4.

  4. Screening of Drug Metabolizing Enzymes for the Ginsenoside Compound K In Vitro: An Efficient Anti-Cancer Substance Originating from Panax Ginseng

    PubMed Central

    Lin, Xiu-Xian; Peng, Shi-Fang; Xiao, Mei-Fang; Huang, Wei-Hua; Wang, Yi-Cheng; Peng, Jing-Bo; Zhang, Wei; Ouyang, Dong-Sheng; Chen, Yao

    2016-01-01

    Ginsenoside compound K (CK), a rare ginsenoside originating from Panax Ginseng, has been found to possess unique pharmacological activities specifically as anti-cancers. However, the role of cytochrome P450s (CYPs) in the metabolism of CK is unclear. In this study, we screened the CYPs for the metabolism of CK in vitro using human liver microsomes (HLMs) or human recombinant CYPs. The results showed that CK inhibited the enzyme activities of CYP2C9 and CYP3A4 in the HLMs. The Km and Vmax values of CK were 84.20±21.92 μM and 0.28±0.04 nmol/mg protein/min, respectively, for the HLMs; 34.63±10.48 μM and 0.45±0.05 nmol/nmol P450/min, respectively, for CYP2C9; and 27.03±5.04 μM and 0.68±0.04 nmol/nmol P450/min, respectively, for CYP3A4. The IC50 values were 16.00 μM and 9.83 μM, and Ki values were 14.92 μM and 11.42μM for CYP2C9 and CYP3A4, respectively. Other human CYP isoforms, including CYP1A2, CYP2A6, CYP2D6, CYP2E1, and CYP2C19, showed minimal or no effect on CK metabolism. The results suggested that CK was a substrate and also inhibitors for both CYP2C9 and CYP3A4. Patients using CK in combination with therapeutic drugs that are substrates of CYP2C9 and CYP3A4 for different reasons should be careful, although the inhibiting potency of CK is much poorer than that of enzyme-specific inhibitors. PMID:26845774

  5. Screening of Drug Metabolizing Enzymes for the Ginsenoside Compound K In Vitro: An Efficient Anti-Cancer Substance Originating from Panax Ginseng.

    PubMed

    Xiao, Jian; Chen, Dan; Lin, Xiu-Xian; Peng, Shi-Fang; Xiao, Mei-Fang; Huang, Wei-Hua; Wang, Yi-Cheng; Peng, Jing-Bo; Zhang, Wei; Ouyang, Dong-Sheng; Chen, Yao

    2016-01-01

    Ginsenoside compound K (CK), a rare ginsenoside originating from Panax Ginseng, has been found to possess unique pharmacological activities specifically as anti-cancers. However, the role of cytochrome P450s (CYPs) in the metabolism of CK is unclear. In this study, we screened the CYPs for the metabolism of CK in vitro using human liver microsomes (HLMs) or human recombinant CYPs. The results showed that CK inhibited the enzyme activities of CYP2C9 and CYP3A4 in the HLMs. The Km and Vmax values of CK were 84.20±21.92 μM and 0.28±0.04 nmol/mg protein/min, respectively, for the HLMs; 34.63±10.48 μM and 0.45±0.05 nmol/nmol P450/min, respectively, for CYP2C9; and 27.03±5.04 μM and 0.68±0.04 nmol/nmol P450/min, respectively, for CYP3A4. The IC50 values were 16.00 μM and 9.83 μM, and Ki values were 14.92 μM and 11.42μM for CYP2C9 and CYP3A4, respectively. Other human CYP isoforms, including CYP1A2, CYP2A6, CYP2D6, CYP2E1, and CYP2C19, showed minimal or no effect on CK metabolism. The results suggested that CK was a substrate and also inhibitors for both CYP2C9 and CYP3A4. Patients using CK in combination with therapeutic drugs that are substrates of CYP2C9 and CYP3A4 for different reasons should be careful, although the inhibiting potency of CK is much poorer than that of enzyme-specific inhibitors.

  6. Piezoelectric crystal microbalance measurements of enthalpy of sublimation of C2-C9 dicarboxylic acids

    NASA Astrophysics Data System (ADS)

    Dirri, F.; Palomba, E.; Longobardo, A.; Zampetti, E.

    2016-02-01

    We present here a novel experimental set-up that is able to measure the enthalpy of sublimation of a given compound by means of piezoelectric crystal microbalances (PCMs). The PCM sensors have already been used for space measurements, such as for the detection of organic and non-organic volatile species and refractory materials in planetary environments. In Earth atmospherics applications, PCMs can be also used to obtain some physical-chemical processes concerning the volatile organic compounds (VOCs) present in atmospheric environments. The experimental set-up has been developed and tested on dicarboxylic acids. In this work, a temperature-controlled effusion cell was used to sublimate VOC, creating a molecular flux that was collimated onto a cold PCM. The VOC recondensed onto the PCM quartz crystal, allowing the determination of the deposition rate. From the measurements of deposition rates, it has been possible to infer the enthalpy of sublimation of adipic acid, i.e. ΔHsub : 141.6 ± 0.8 kJ mol-1, succinic acid, i.e. 113.3 ± 1.3 kJ mol-1, oxalic acid, i.e. 62.5 ± 3.1 kJ mol-1, and azelaic acid, i.e. 124.2 ± 1.2 kJ mol-1. The results obtained show an accuracy of 1 % for succinic, adipic, and azelaic acid and within 5 % for oxalic acid and are in very good agreement with previous works (within 6 % for adipic, succinic, and oxalic acid and within 11 % or larger for azelaic acid).

  7. Piezoelectric crystal microbalance measurements of enthalpy of sublimation of C2-C9 dicarboxylic acids

    NASA Astrophysics Data System (ADS)

    Dirri, F.; Palomba, E.; Longobardo, A.; Zampetti, E.

    2015-07-01

    We present here a novel experimental setup able to measure the enthalpy of sublimation of a given compound by means of Piezoelectric Crystal Microbalances (PCM). This experiment was performed in the TG-Lab facility in IAPS-INAF, dedicated to the development of TGA sensors for space measurements, such as detection of organic and non-organic volatile species and refractory materials in planetary environments. In order to study physical-chemical processes concerning the Volatile Organic Compounds (VOC) present in atmospheric environments, the setup has been tested on Dicarboxylic acids. Acids with low molecular weight are among the components of organic fraction of particulate matter in the atmosphere, coming from different sources (biogenic and anthropogenic). Considering their relative abundance, it is useful to consider Dicarboxylic acid as "markers" to define the biogenic or anthropogenic origin of the aerosol, thus obtaining some information of the emission sources. In this work, a temperature controlled effusion cell was used to sublimate VOC, creating a molecular flux that was collimated onto a cold PCM. The VOC re-condensed onto the PCM quartz crystal allowing the determination of the deposition rate. From the measurements of deposition rates, it was possible to infer the enthalpy of sublimation of Adipic acid, i.e. Δ Hsub: 141.6 ± 0.8 kJ mol-1, Succinic acid, i.e. 113.3 ± 1.3 kJ mol-1, Oxalic acid, i.e. 62.5 ± 3.1 kJ mol-1 and Azelaic acid, i.e. 124.2 ± 1.2 kJ mol-1 (weight average values). The results obtained are in very good agreement with literature within 10 % for the Adipic, Succinic and Oxalic acid.

  8. Gas-Phase Reactions of Atomic Gold Cations with Linear Alkanes (C2-C9).

    PubMed

    Zhang, Ting; Li, Zi-Yu; Zhang, Mei-Qi; He, Sheng-Gui

    2016-06-30

    To develop proper ionization methods for alkanes, the reactivity of bare or ligated transition metal ions toward alkanes has attracted increasing interests. In this study, the reactions of the gold cations with linear alkanes from ethane up to nonane (CnH2n+2, n = 2-9) under mild conditions have been characterized by mass spectrometry and density functional theory calculations. When reacting with Au(+), small alkanes (n = 2-6) were confirmed to follow specific reaction channels of dehydrogenation for ethane and hydride transfer for others to generate product ions characteristic of the original alkanes, which indicates that Au(+) can act as a reagent ion to ionize alkanes from ethane to n-hexane. Strong dependence of the chain length of alkanes was observed for the rate constants and reaction efficiencies. Extensive fragmentation took place for larger alkanes (n > 6). Theoretical results show that the fragmentation induced by the hydride transfer occurs after the release of AuH. Moreover, the fragmentation of n-heptane was successfully avoided when the reaction took place in a high-pressure reactor. This implies that Au(+) is a potential reagent ion to ionize linear and even the branched alkanes. PMID:27266670

  9. VKORC1 and CYP2C9 Gene Polymorphisms and Warfarin Management

    ClinicalTrials.gov

    2009-09-02

    Atrial Fibrillation; Cardiac Thrombus; Deep Vein Thrombosis; Pulmonary Embolism; Heart Valve Replacement (Mechanical or Biological With AF); Cardiomyopathy (Ischemic or Dilated); Peripheral Vascular Disease

  10. Effect of Single Nucleotide Polymorphisms in Cytochrome P450 Isoenzyme and N-Acetyltransferase 2 Genes on the Metabolism of Artemisinin-Based Combination Therapies in Malaria Patients from Cambodia and Tanzania

    PubMed Central

    Staehli Hodel, Eva Maria; Csajka, Chantal; Ariey, Frédéric; Guidi, Monia; Kabanywanyi, Abdunoor Mulokozi; Duong, Socheat; Decosterd, Laurent Arthur; Olliaro, Piero; Genton, Blaise

    2013-01-01

    The pharmacogenetics of antimalarial agents are poorly known, although the application of pharmacogenetics might be critical in optimizing treatment. This population pharmacokinetic-pharmacogenetic study aimed at assessing the effects of single nucleotide polymorphisms (SNPs) in cytochrome P450 isoenzyme genes (CYP, namely, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP3A4, and CYP3A5) and the N-acetyltransferase 2 gene (NAT2) on the pharmacokinetics of artemisinin-based combination therapies in 150 Tanzanian patients treated with artemether-lumefantrine, 64 Cambodian patients treated with artesunate-mefloquine, and 61 Cambodian patients treated with dihydroartemisinin-piperaquine. The frequency of SNPs varied with the enzyme and the population. Higher frequencies of mutant alleles were found in Cambodians than Tanzanians for CYP2C9*3, CYP2D6*10 (100C→T), CYP3A5*3, NAT2*6, and NAT2*7. In contrast, higher frequencies of mutant alleles were found in Tanzanians for CYP2D6*17 (1023C→T and 2850C→T), CYP3A4*1B, NAT2*5, and NAT2*14. For 8 SNPs, no significant differences in frequencies were observed. In the genetic-based population pharmacokinetic analyses, none of the SNPs improved model fit. This suggests that pharmacogenetic data need not be included in appropriate first-line treatments with the current artemisinin derivatives and quinolines for uncomplicated malaria in specific populations. However, it cannot be ruled out that our results represent isolated findings, and therefore more studies in different populations, ideally with the same artemisinin-based combination therapies, are needed to evaluate the influence of pharmacogenetic factors on the clearance of antimalarials. PMID:23229480

  11. Enantioselective metabolism of the endocrine disruptor pesticide methoxychlor by human cytochromes P450 (P450s): major differences in selective enantiomer formation by various P450 isoforms.

    PubMed

    Hu, Yiding; Kupfer, David

    2002-12-01

    Methoxychlor, a currently used pesticide that in mammals elicits proestrogenic/estrogenic activity and reproductive toxicity, has been classified as a prototype endocrine disruptor. Methoxychlor is prochiral, and its metabolites 1,1,1-trichloro-2-(4-hydroxyphenyl)-2-(4-methoxyphenyl)ethane (mono-OH-M); 1,1,1-trichloro- 2-(4-methoxyphenyl)-2-(3, 4-dihydroxyphenyl)ethane (catechol-M); and 1,1,1-trichloro-2-(4-hydroxyphenyl)-2-(3, 4-dihydroxyphenyl)ethane (tris-OH-M) are chiral; whereas 1,1,1-trichloro-2, 2-bis(4-hydroxyphenyl)ethane (bis-OH-M) is achiral. These metabolites are formed during methoxychlor incubation with liver microsomes or recombinant cytochrome p450s (rp450s). Since methoxychlor-metabolite enantiomers may have different estrogenic/antiestrogenic/antiandrogenic activities than corresponding racemates, the possibility that p450s preferentially generate or use R or S enantiomers, was examined. Indeed, rCYP1A2 and r2A6 mono-demethylated methoxychlor primarily into (R)-mono-OH-M at 91 and 75%, respectively, whereas rCYP1A1, 2B6, 2C8, 2C9, 2C19, and 2D6 formed the (S)-enantiomer at 69, 66, 75, 95, 96, and 80%, respectively. However, rCYP3A4, 3A5, and 2B1(rat) weakly demethylated methoxychlor without enantioselectivity. Human liver microsomes generated (S)-mono-OH-M (77-87%), suggesting that CYP1A2 and 2A6 display only minor catalytic contribution. P450 inhibitors demonstrated that CYP2C9 and possibly 2C19 are major hepatic catalysts forming (S)-mono-OH-M, and CYP1A2 is primarily involved in forming the (R)-mono-OH-M. Demethylation rate of (S)-mono-OH-M versus (R)-mono-OH-M forming achiral bis-OH-M by rCYP1A2 was 97/3, compared with 15/85 and 17/83 for rCYP2C9 and 2C19, respectively, indicating opposite substrate enantioselectivity of rCYP1A2 versus 2C9 and 2C19. Also, rCYP1A2 preferentially O-demethylated (R)-catechol-M into (R)-tris-OH-M (at 80%), contrasting r2C9 and r2C19 that yielded (S)-tris-OH-M at 80 and 77%, respectively. Ortho-hydroxylation of

  12. Frequencies of 23 Functionally Significant Variant Alleles Related with Metabolism of Antineoplastic Drugs in the Chilean Population: Comparison with Caucasian and Asian Populations

    PubMed Central

    Roco, Ángela; Quiñones, Luis; Agúndez, José A. G.; García-Martín, Elena; Squicciarini, Valentina; Miranda, Carla; Garay, Joselyn; Farfán, Nancy; Saavedra, Iván; Cáceres, Dante; Ibarra, Carol; Varela, Nelson

    2012-01-01

    Cancer is a leading cause of death worldwide. The cancer incidence rate in Chile is 133.7/100,000 inhabitants and it is the second cause of death, after cardiovascular diseases. Most of the antineoplastic drugs are metabolized to be detoxified, and some of them to be activated. Genetic polymorphisms of drug-metabolizing enzymes can induce deep changes in enzyme activity, leading to individual variability in drug efficacy and/or toxicity. The present research describes the presence of genetic polymorphisms in the Chilean population, which might be useful in public health programs for personalized treatment of cancer, and compares these frequencies with those reported for Asian and Caucasian populations, as a contribution to the evaluation of ethnic differences in the response to chemotherapy. We analyzed 23 polymorphisms in a group of 253 unrelated Chilean volunteers from the general population. The results showed that CYP2A6*2, CYP2A6*3, CYP2D6*3, CYP2C19*3, and CYP3A4*17 variant alleles are virtually absent in Chileans. CYP1A1*2A allele frequency (0.37) is similar to that of Caucasians and higher than that reported for Japanese people. Allele frequencies for CYP3A5*3(0.76) and CYP2C9*3(0.04) are similar to those observed in Japanese people. CYP1A1*2C(0.32), CYP1A2*1F(0.77), CYP3A4*1B(0.06), CYP2D6*2(0.41), and MTHFR T(0.52) allele frequencies are higher than the observed either in Caucasian or in Japanese populations. Conversely, CYP2C19*2 allelic frequency (0.12), and genotype frequencies for GSTT1 null (0.11) and GSTM1 null (0.36) are lower than those observed in both populations. Finally, allele frequencies for CYP2A6*4(0.04), CYP2C8*3(0.06), CYP2C9*2(0.06), CYP2D6*4(0.12), CYP2E1*5B(0.14), CYP2E1*6(0.19), and UGT2B7*2(0.40) are intermediate in relation to those described in Caucasian and in Japanese populations, as expected according to the ethnic origin of the Chilean population. In conclusion, our findings support the idea that ethnic variability must be

  13. Evaluation of drug interaction potential of Labisia pumila (Kacip Fatimah) and its constituents

    PubMed Central

    Manda, Vamshi K.; Dale, Olivia R.; Awortwe, Charles; Ali, Zulfiqar; Khan, Ikhlas A.; Walker, Larry A.; Khan, Shabana I.

    2014-01-01

    Labisia pumila (Kacip Fatimah) is a popular herb in Malaysia that has been traditionally used in a number of women’s health applications such as to improve libido, relieve postmenopausal symptoms, and to facilitate or hasten delivery in childbirth. In addition, the constituents of this plant have been reported to possess anticancer, antioxidant, and anti-inflammatory properties. Clinical studies have indicated that cytochrome P450s (CYPs), P-glycoprotein (P-gp), and Pregnane X receptor (PXR) are the three main modulators of drug-drug interactions which alter the absorption, distribution, and metabolism of drugs. Given the widespread use of Kacip Fatimah in dietary supplements, the current study focuses on determining the potential of its constituents to affect the activities of CYPs, P-gp, or PXR using in vitro assays which may provide useful information toward the risk of herb-drug interaction with concomitantly used drugs. Six compounds isolated from the roots of L. pumila (2 saponins and 4 alkyl phenols) were tested, in addition to the methanolic extract. The extract of L. pumila showed a significant time dependent inhibition (TDI) of CYP3A4, reversible inhibition of CYP2C9 and 2C19 and a weak inhibition of 1A2 and 2D6 as well as an inhibition of P-gp and rifampicin-induced PXR activation. The alkyl phenols inhibited CYP3A4 (TDI), CYP2C9, and 2C19 (reversible) while saponins inhibited P-gp and PXR. In conclusion, L. pumila and its constituents showed significant modulation of all three regulatory proteins (CYPs, P-gp, and PXR) suggesting a potential to alter the pharmacokinetic and pharmacodynamic properties of conventional drugs if used concomitantly. PMID:25152732

  14. Inhibitory Effects of Aschantin on Cytochrome P450 and Uridine 5'-diphospho-glucuronosyltransferase Enzyme Activities in Human Liver Microsomes.

    PubMed

    Kwon, Soon-Sang; Kim, Ju-Hyun; Jeong, Hyeon-Uk; Cho, Yong Yeon; Oh, Sei-Ryang; Lee, Hye Suk

    2016-01-01

    Aschantin is a bioactive neolignan found in Magnolia flos with antiplasmodial, Ca(2+)-antagonistic, platelet activating factor-antagonistic, and chemopreventive activities. We investigated its inhibitory effects on the activities of eight major human cytochrome P450 (CYP) and uridine 5'-diphospho-glucuronosyltransferase (UGT) enzymes of human liver microsomes to determine if mechanistic aschantin-enzyme interactions were evident. Aschantin potently inhibited CYP2C8-mediated amodiaquine N-de-ethylation, CYP2C9-mediated diclofenac 4'-hydroxylation, CYP2C19-mediated [S]-mephenytoin 4'-hydroxylation, and CYP3A4-mediated midazolam 1'-hydroxylation, with Ki values of 10.2, 3.7, 5.8, and 12.6 µM, respectively. Aschantin at 100 µM negligibly inhibited CYP1A2-mediated phenacetin O-de-ethylation, CYP2A6-mediated coumarin 7-hydroxylation, CYP2B6-mediated bupropion hydroxylation, and CYP2D6-mediated bufuralol 1'-hydroxylation. At 200 µM, it weakly inhibited UGT1A1-catalyzed SN-38 glucuronidation, UGT1A6-catalyzed N-acetylserotonin glucuronidation, and UGT1A9-catalyzed mycophenolic acid glucuronidation, with IC50 values of 131.7, 144.1, and 71.0 µM, respectively, but did not show inhibition against UGT1A3, UGT1A4, or UGT2B7 up to 200 µM. These in vitro results indicate that aschantin should be examined in terms of potential interactions with pharmacokinetic drugs in vivo. It exhibited potent mechanism-based inhibition of CYP2C8, CYP2C9, CYP2C19, and CYP3A4. PMID:27128896

  15. Contribution of Cytochrome P450 and ABCB1 Genetic Variability on Methadone Pharmacokinetics, Dose Requirements, and Response

    PubMed Central

    Fonseca, Francina; de la Torre, Rafael; Díaz, Laura; Pastor, Antonio; Cuyàs, Elisabet; Pizarro, Nieves; Khymenets, Olha; Farré, Magí; Torrens, Marta

    2011-01-01

    Although the efficacy of methadone maintenance treatment (MMT) in opioid dependence disorder has been well established, the influence of methadone pharmacokinetics in dose requirement and clinical outcome remains controversial. The aim of this study is to analyze methadone dosage in responder and nonresponder patients considering pharmacogenetic and pharmacokinetic factors that may contribute to dosage adequacy. Opioid dependence patients (meeting Diagnostic and Statistical Manual of Mental Disorders, [4th Edition] criteria) from a MMT community program were recruited. Patients were clinically assessed and blood samples were obtained to determine plasma concentrations of (R,S)-, (R) and (S)- methadone and to study allelic variants of genes encoding CYP3A5, CYP2D6, CYP2B6, CYP2C9, CYP2C19, and P-glycoprotein. Responders and nonresponders were defined by illicit opioid consumption detected in random urinalysis. The final sample consisted in 105 opioid dependent patients of Caucasian origin. Responder patients received higher doses of methadone and have been included into treatment for a longer period. No differences were found in terms of genotype frequencies between groups. Only CYP2D6 metabolizing phenotype differences were found in outcome status, methadone dose requirements, and plasma concentrations, being higher in the ultrarapid metabolizers. No other differences were found between phenotype and responder status, methadone dose requirements, neither in methadone plasma concentrations. Pharmacokinetic factors could explain some but not all differences in MMT outcome and methadone dose requirements. PMID:21589866

  16. Cytochrome P450 inhibition potential of new psychoactive substances of the tryptamine class.

    PubMed

    Dinger, Julia; Woods, Campbell; Brandt, Simon D; Meyer, Markus R; Maurer, Hans H

    2016-01-22

    New psychoactive substances (NPS) are not tested for their cytochrome P450 (CYP) inhibition potential before consumption. Therefore, this potential was explored for tryptamine-derived NPS (TDNPS) including alpha-methyl tryptamines (AMTs), dimethyl tryptamines (DMTs), diallyl tryptamines (DALTs), and diisopropyl tryptamines (DiPTs) using test substrates preferred by the Food and Drug Administration in a cocktail assay. All tested TDNPS with the exception of DMT inhibited CYP2D6 activity with IC50 values below 100μM. DALTs inhibited CYP2D6 activity similar to paroxetine and quinidine and CYP1A2 activity comparable to fluvoxamine. 5-Methoxy-N,N-diallyltryptamine reduced in vivo the caffeine metabolism in rats consistent with in vitro results. Five of the AMTs also inhibited CYP1A2 activity comparable to amiodarone. AMT and 6-F-AMT inhibited CYP2A6 activity in the range of the test inhibitor tranylcypromine. CYP2B6 activity was inhibited by 19 tryptamines, but weakly compared to efavirenz. CYP2C8 activity was inhibited by five of the tested TDNPS and three showed values comparable to trimethoprim and gemfibrozil. Six tryptamines inhibited CYP2C9 and seven CYP2C19 activities comparable to fluconazole and chloramphenicol, respectively. Nineteen compounds showed inhibition of CYP2E1 and 18 of CYP3A activity, respectively. These results showed that the CYP inhibition by TDNPS might be clinically relevant, but clinical studies are needed to explore this further. PMID:26599973

  17. Impact of inter-individual differences in drug metabolism and pharmacokinetics on safety evaluation.

    PubMed

    Dorne, J L C M

    2004-12-01

    Safety evaluation aims to assess the dose-response relationship to determine a dose/level of exposure for food contaminants below which no deleterious effect is measurable that is 'without appreciable health risk' when consumed daily over a lifetime. These safe levels, such as the acceptable daily intake (ADI) have been derived from animal studies using surrogates for the threshold such as the no-observed-adverse-effect-level (NOAEL). The extrapolation from the NOAEL to the human safe intake uses a 100-fold uncertainty factor, defined as the product of two 10-fold factors allowing for human variability and interspecies differences. The 10-fold factor for human variability has been further subdivided into two factors of 10(0.5) (3.16) to cover toxicokinetics and toxicodynamics and this subdivsion allows for the replacement of an uncertainty factor with a chemical-specific adjustment factor (CSAF) when compound-specific data are available. Recently, an analysis of human variability in pharmacokinetics for phase I metabolism (CYP1A2, CYP2A6, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4, hydrolysis, alcohol dehydrogenase), phase II metabolism (N-acetyltransferase, glucuronidation, glycine conjugation, sulphation) and renal excretion was used to derive pathway-related uncertainty factors in subgroups of the human population (healthy adults, effects of ethnicity and age). Overall, the pathway-related uncertainty factors (99th centile) were above the toxicokinetic uncertainty factor for healthy adults exposed to xenobiotics handled by polymorphic metabolic pathways (and assuming the parent compound was the proximate toxicant) such as CYP2D6 poor metabolizers (26), CYP2C19 poor metabolizers (52) and NAT-2 slow acetylators (5.2). Neonates were the most susceptible subgroup of the population for pathways with available data [CYP1A2 and glucuronidation (12), CYP3A4 (14), glycine conjugation (28)]. Data for polymorphic pathways were not available in neonates but uncertainty factors

  18. Impact of inter-individual differences in drug metabolism and pharmacokinetics on safety evaluation.

    PubMed

    Dorne, J L C M

    2004-12-01

    Safety evaluation aims to assess the dose-response relationship to determine a dose/level of exposure for food contaminants below which no deleterious effect is measurable that is 'without appreciable health risk' when consumed daily over a lifetime. These safe levels, such as the acceptable daily intake (ADI) have been derived from animal studies using surrogates for the threshold such as the no-observed-adverse-effect-level (NOAEL). The extrapolation from the NOAEL to the human safe intake uses a 100-fold uncertainty factor, defined as the product of two 10-fold factors allowing for human variability and interspecies differences. The 10-fold factor for human variability has been further subdivided into two factors of 10(0.5) (3.16) to cover toxicokinetics and toxicodynamics and this subdivsion allows for the replacement of an uncertainty factor with a chemical-specific adjustment factor (CSAF) when compound-specific data are available. Recently, an analysis of human variability in pharmacokinetics for phase I metabolism (CYP1A2, CYP2A6, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4, hydrolysis, alcohol dehydrogenase), phase II metabolism (N-acetyltransferase, glucuronidation, glycine conjugation, sulphation) and renal excretion was used to derive pathway-related uncertainty factors in subgroups of the human population (healthy adults, effects of ethnicity and age). Overall, the pathway-related uncertainty factors (99th centile) were above the toxicokinetic uncertainty factor for healthy adults exposed to xenobiotics handled by polymorphic metabolic pathways (and assuming the parent compound was the proximate toxicant) such as CYP2D6 poor metabolizers (26), CYP2C19 poor metabolizers (52) and NAT-2 slow acetylators (5.2). Neonates were the most susceptible subgroup of the population for pathways with available data [CYP1A2 and glucuronidation (12), CYP3A4 (14), glycine conjugation (28)]. Data for polymorphic pathways were not available in neonates but uncertainty factors

  19. Evaluation of inhibitory effects of caffeic acid and quercetin on human liver cytochrome p450 activities.

    PubMed

    Rastogi, Himanshu; Jana, Snehasis

    2014-12-01

    When herbal drugs and conventional allopathic drugs are used together, they can interact in our body which can lead to the potential for herb-drug interactions. This work was conducted to evaluate the herb-drug interaction potential of caffeic acid and quercetin mediated by cytochrome P450 (CYP) inhibition. Human liver microsomes (HLMs) were added to each selective probe substrates of cytochrome P450 enzymes with or without of caffeic acid and quercetin. IC50 , Ki values, and the types of inhibition were determined. Both caffeic acid and quercetin were potent competitive inhibitors of CYP1A2 (Ki = 1.16 and 0.93 μM, respectively) and CYP2C9 (Ki = 0.95 and 1.67 μM, respectively). Caffeic acid was a potent competitive inhibitor of CYP2D6 (Ki = 1.10 μM) and a weak inhibitor of CYP2C19 and CYP3A4 (IC50  > 100 μM). Quercetin was a potent competitive inhibitor of CYP 2C19 and CYP3A4 (Ki = 1.74 and 4.12 μM, respectively) and a moderate competitive inhibitor of CYP2D6 (Ki = 18.72 μM). These findings might be helpful for safe and effective use of polyphenols in clinical practice. Our data indicated that it is necessary to study the in vivo interactions between drugs and pharmaceuticals with dietary polyphenols. PMID:25196644

  20. Significant inhibitory impact of dibenzyl trisulfide and extracts of Petiveria alliacea on the activities of major drug-metabolizing enzymes in vitro: An assessment of the potential for medicinal plant-drug interactions.

    PubMed

    Murray, J; Picking, D; Lamm, A; McKenzie, J; Hartley, S; Watson, C; Williams, L; Lowe, H; Delgoda, R

    2016-06-01

    Dibenzyl trisulfide (DTS) is the major active ingredient expressed in Petiveria alliacea L., a shrub widely used for a range of conditions, such as, arthritis, asthma and cancer. Given its use alone and concomitantly with prescription medicines, we undertook to investigate its impact on the activities of important drug metabolizing enzymes, the cytochromes P450 (CYP), a key family of enzymes involved in many adverse drug reactions. DTS and seven standardized extracts from the plant were assessed for their impact on the activities of CYPs 1A2, 2C19, 2C9, 2D6 and 3A4 on a fluorometric assay. DTS revealed significant impact against the activities of CYPs 1A2, 2C19 and 3A4 with IC50 values of 1.9, 4.0 and 3.2μM, respectively, which are equivalent to known standard inhibitors of these enzymes (furafylline, and tranylcypromine), and the most potent interaction with CYP1A2 displayed irreversible enzyme kinetics. The root extract, drawn with 96% ethanol (containing 2.4% DTS), displayed IC50 values of 5.6, 3.9 and 4.2μg/mL respectively, against the same isoforms, CYPs 1A2, 2C19 and 3A4. These investigations identify DTS as a valuable CYP inhibitor and P. alliacea as a candidate plant worthy of clinical trials to confirm the conclusions that extracts yielding high DTS may lead to clinically relevant drug interactions, whilst extracts yielding low levels of DTS, such as aqueous extracts, are unlikely to cause adverse herb-drug interactions.

  1. Significant inhibitory impact of dibenzyl trisulfide and extracts of Petiveria alliacea on the activities of major drug-metabolizing enzymes in vitro: An assessment of the potential for medicinal plant-drug interactions.

    PubMed

    Murray, J; Picking, D; Lamm, A; McKenzie, J; Hartley, S; Watson, C; Williams, L; Lowe, H; Delgoda, R

    2016-06-01

    Dibenzyl trisulfide (DTS) is the major active ingredient expressed in Petiveria alliacea L., a shrub widely used for a range of conditions, such as, arthritis, asthma and cancer. Given its use alone and concomitantly with prescription medicines, we undertook to investigate its impact on the activities of important drug metabolizing enzymes, the cytochromes P450 (CYP), a key family of enzymes involved in many adverse drug reactions. DTS and seven standardized extracts from the plant were assessed for their impact on the activities of CYPs 1A2, 2C19, 2C9, 2D6 and 3A4 on a fluorometric assay. DTS revealed significant impact against the activities of CYPs 1A2, 2C19 and 3A4 with IC50 values of 1.9, 4.0 and 3.2μM, respectively, which are equivalent to known standard inhibitors of these enzymes (furafylline, and tranylcypromine), and the most potent interaction with CYP1A2 displayed irreversible enzyme kinetics. The root extract, drawn with 96% ethanol (containing 2.4% DTS), displayed IC50 values of 5.6, 3.9 and 4.2μg/mL respectively, against the same isoforms, CYPs 1A2, 2C19 and 3A4. These investigations identify DTS as a valuable CYP inhibitor and P. alliacea as a candidate plant worthy of clinical trials to confirm the conclusions that extracts yielding high DTS may lead to clinically relevant drug interactions, whilst extracts yielding low levels of DTS, such as aqueous extracts, are unlikely to cause adverse herb-drug interactions. PMID:27105957

  2. Effects of methoxychlor and 2,2-bis ( p -hydroxyphenyl)-1,1,1-trichloroethane on cytochrome P450 enzyme activities in human and rat livers.

    PubMed

    Chen, Bingbing; Pan, Peipei; Wang, Li; Chen, Menchun; Dong, Yaoyao; Ge, Ren-Shan; Hu, Guo-Xin

    2015-01-01

    Cytochrome P450 (CYP) enzymes are involved in the metabolism of endogenous and exogenous compounds. Human and rat liver microsomes were used to investigate the inhibitory effects of methoxychlor (MXC) and its metabolite 2,2-bis(p-hydroxyphenyl)-1,1,1-trichloroethane (HPTE) on the activities of corresponding human and rat CYPs. Probe drugs were used to test the inhibitory effects of MXC and HPTE on human and rat CYPs. The results showed that MXC and HPTE inhibited both human CYP2C9 and rat liver CYP2C11 activity, with half-maximal inhibitory concentration (IC50) values of 15.47 ± 0.36 (MXC) and 8.87 ± 0.53 μmol/l (HPTE) for human CYP2C9, and of 22.45 ± 1.48 (MXC) and 24.63 ± 1.35 μmol/l (HPTE) for rat CYP2C11. MXC and HPTE had no effects on human CYP2C19 activity but inhibited rat CYP2C6 activity with IC50 values of 14.84 ± 0.04 (MXC) and 8.72 ± 0.25 μmol/l (HPTE). With regard to human CYP2D6 and rat CYP2D2 activity, only HPTE potently inhibited human CYP2D6 activity, with an IC50 value of 16.56 ± 0.69 μmol/l. Both chemicals had no effect on human CYP3A4 and rat CYP3A1 activity. In summary, MXC and HPTE are potent inhibitors of some human and rat CYPs.

  3. Interethnic variability of pharmacogenetic biomarkers in Mexican healthy volunteers: a report from the RIBEF (Ibero-American Network of Pharmacogenetics and Pharmacogenomics).

    PubMed

    Fricke-Galindo, Ingrid; Jung-Cook, Helgi; LLerena, Adrián; López-López, Marisol

    2016-06-01

    Mexico presents a complex population diversity integrated by Mexican indigenous (MI) (7% of Mexico's population) and Mexican mestizos (MMs). This composition highlights the importance of pharmacogenetic studies in Mexican populations. The aims of this study were to analyze the reported frequencies of the most relevant pharmacogenetic biomarkers and metabolic phenotypes in healthy volunteers from Mexican populations and to assess its interethnic variability across MI and MM populations. After a literature search in PubMed, and according to previously defined inclusion criteria, 63 pharmacogenetic studies performed in Mexican healthy volunteers up to date were selected. These reports comprised 56,292 healthy volunteers (71.58% MM). Allele frequencies in 31 pharmacogenetic biomarkers, from 121 searched, are described. Nine of these biomarkers presented variation within MM and MI groups. The frequencies of CYP2D6*3, *4, *5, *10, *17, *35 and *41 alleles in the MM group were different from those reported in the MI group. CYP2C9*2 and *3 alleles were more frequent in MM than in MI populations (χ2 test, p<0.05). CYP2C19*3 allele was not found in the MM or MI populations reported. For UGT1A1*28, only one study was found. HLA-A*31:01 and HLA-B*15:02 were present in some MM and MI populations. Poor metabolizers for CYP2D6 and CYP2C9 were more frequent in MM than in MI groups (χ2 test, p<0.05). Only 26% of the relevant pharmacogenetic biomarkers searched have been studied in Mexican healthy volunteers; therefore, further studies are warranted. The frequency variation of biomarkers in MM and MI populations could be important for the clinical implementation of pharmacogenetics in Mexico.

  4. An in vitro evaluation of cytochrome P450 inhibition and P-glycoprotein interaction with goldenseal, Ginkgo biloba, grape seed, milk thistle, and ginseng extracts and their constituents.

    PubMed

    Etheridge, Amy S; Black, Sherry R; Patel, Purvi R; So, James; Mathews, James M

    2007-07-01

    Drug-herb interactions can result from the modulation of the activities of cytochrome P450 (P450) and/or drug transporters. The effect of extracts and individual constituents of goldenseal, Ginkgo biloba (and its hydrolyzate), grape seed, milk thistle, and ginseng on the activities of cytochrome P450 enzymes CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, and CYP3A4 in human liver microsomes were determined using enzyme-selective probe substrates, and their effect on human P-glycoprotein (Pgp) was determined using a baculovirus expression system by measuring the verapamil-stimulated, vanadate-sensitive ATPase activity. Extracts were analyzed by HPLC to standardize their concentration(s) of constituents associated with the pharmacological activity, and to allow comparison of their effects on P450 and Pgp with literature values. Many of the extracts/constituents exerted > or = 50 % inhibition of P450 activity. These include those from goldenseal (normalized to alkaloid content) inhibiting CYP2C8, CYP2D6, and CYP3A4 at 20 microM, ginkgo inhibiting CYP2C8 at 10 microM, grape seed inhibiting CYP2C9 and CYP3A4 at 10 microM, milk thistle inhibiting CYP2C8 at 10 microM, and ginsenosides F1 and Rh1 (but not ginseng extract) inhibiting CYP3A4 at 10 microM. Goldenseal extracts/constituents (20 microM, particularly hydrastine) and ginsenoside Rh1 stimulated ATPase at about half of the activity of the model substrate, verapamil (20 microM). The data suggest that the clearance of a variety of drugs may be diminished by concomitant use of these herbs via inhibition of P450 enzymes, but less so by Pgp-mediated effects.

  5. Interethnic variability of pharmacogenetic biomarkers in Mexican healthy volunteers: a report from the RIBEF (Ibero-American Network of Pharmacogenetics and Pharmacogenomics).

    PubMed

    Fricke-Galindo, Ingrid; Jung-Cook, Helgi; LLerena, Adrián; López-López, Marisol

    2016-06-01

    Mexico presents a complex population diversity integrated by Mexican indigenous (MI) (7% of Mexico's population) and Mexican mestizos (MMs). This composition highlights the importance of pharmacogenetic studies in Mexican populations. The aims of this study were to analyze the reported frequencies of the most relevant pharmacogenetic biomarkers and metabolic phenotypes in healthy volunteers from Mexican populations and to assess its interethnic variability across MI and MM populations. After a literature search in PubMed, and according to previously defined inclusion criteria, 63 pharmacogenetic studies performed in Mexican healthy volunteers up to date were selected. These reports comprised 56,292 healthy volunteers (71.58% MM). Allele frequencies in 31 pharmacogenetic biomarkers, from 121 searched, are described. Nine of these biomarkers presented variation within MM and MI groups. The frequencies of CYP2D6*3, *4, *5, *10, *17, *35 and *41 alleles in the MM group were different from those reported in the MI group. CYP2C9*2 and *3 alleles were more frequent in MM than in MI populations (χ2 test, p<0.05). CYP2C19*3 allele was not found in the MM or MI populations reported. For UGT1A1*28, only one study was found. HLA-A*31:01 and HLA-B*15:02 were present in some MM and MI populations. Poor metabolizers for CYP2D6 and CYP2C9 were more frequent in MM than in MI groups (χ2 test, p<0.05). Only 26% of the relevant pharmacogenetic biomarkers searched have been studied in Mexican healthy volunteers; therefore, further studies are warranted. The frequency variation of biomarkers in MM and MI populations could be important for the clinical implementation of pharmacogenetics in Mexico. PMID:26812836

  6. In vitro inhibition and induction of human cytochrome P450 enzymes by mirabegron, a potent and selective β3-adrenoceptor agonist.

    PubMed

    Takusagawa, Shin; Miyashita, Aiji; Iwatsubo, Takafumi; Usui, Takashi

    2012-12-01

    The potential for mirabegron, a β(3)-adrenoceptor agonist for the treatment of overactive bladder, to cause drug-drug interactions via inhibition or induction of cytochrome P450 (CYP) enzymes was investigated in vitro. Mirabegron was shown to be a time-dependent inhibitor of CYP2D6 in the presence of NADPH as the IC(50) value in human liver microsomes decreased from 13 to 4.3 μM after 30-min pre-incubation. Further evaluation indicated that mirabegron may act partly as an irreversible or quasi-irreversible metabolism-dependent inhibitor of CYP2D6. Therefore, the potential of mirabegron to inhibit the metabolism of CYP2D6 substrates in vivo cannot be excluded. Mirabegron was predicted not to cause clinically significant metabolic drug-drug interactions via inhibition of CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2E1, or CYP3A4/5 because the IC(50) values for these enzymes both with and without pre-incubation were >100 μM (370 times maximum human plasma concentration [C(max)]). Whereas positive controls (100 µM omeprazole and 10 µM rifampin) caused the anticipated CYP induction, the highest concentration of mirabegron (10 µM; 37 times plasma C(max)) had minimal effect on CYP1A2 and CYP3A4/5 activity, and CYP1A2 and CYP3A4 mRNA levels in freshly isolated human hepatocytes, suggesting that mirabegron is not an inducer of these enzymes.

  7. Immobilized Cytochrome P450 2C9 (CYP2C9): Applications for Metabolite Generation, Monitoring Protein-Protein Interactions, and Improving In-vivo Predictions Using Enhanced In-vitro Models

    NASA Astrophysics Data System (ADS)

    Wollenberg, Lance A.

    Cytochrome P450 (P450) enzymes are a family of oxoferroreductase enzymes containing a heme moiety and are well known to be involved in the metabolism of a wide variety of endogenous and xenobiotic materials. It is estimated that roughly 75% of all pharmaceutical compounds are metabolized by these enzymes. Traditional reconstituted in-vitro incubation studies using recombinant P450 enzymes are often used to predict in-vivo kinetic parameters of a drug early in development. However, in many cases, these reconstituted incubations are prone to aggregation which has been shown to affect the catalytic activity of an enzyme. Moreover, the presence of other isoforms of P450 enzymes present in a metabolic incubation, as is the case with microsomal systems, may affect the catalytic activity of an enzyme through isoform-specific protein-protein interactions. Both of these effects may result in inaccurate prediction of in-vivo drug metabolism using in-vitro experiments. Here we described the development of immobilized P450 constructs designed to elucidate the effects of aggregation and protein-protein interactions between P450 isoforms on catalytic activities. The long term objective of this project is to develop a system to control the oligomeric state of Cytochrome P450 enzymes to accurately elucidate discrepancies between in vitro reconstituted systems and actual in vivo drug metabolism for the precise prediction of metabolic activity. This approach will serve as a system to better draw correlations between in-vivo and in-vitro drug metabolism data. The central hypothesis is that Cytochrome P450 enzymes catalytic activity can be altered by protein-protein interactions occurring between Cytochrome P450 enzymes involved in drug metabolism, and is dependent on varying states of protein aggregation. This dissertation explains the details of the construction and characterization of a nanostructure device designed to control the state of aggregation of a P450 enzyme. Moreover, applications of immobilized P450 enzyme constructs will also be used for monitoring protein-protein interaction and metabolite production with the use of immobilized-P450 bioreactor constructs. This work provides insight into the effect on catalytic activity caused by both P450 aggregation as well as isoform-specific protein-protein interactions and provides insight in the production of biosynthetically produced drug metabolites

  8. Simultaneous Screening of Activities of Five Cytochrome P450 and Four Uridine 5'-Diphospho-glucuronosyltransferase Enzymes in Human Liver Microsomes Using Cocktail Incubation and Liquid Chromatography-Tandem Mass Spectrometry.

    PubMed

    Lee, Boram; Ji, Hyeon-Kyeong; Lee, Taeho; Liu, Kwang-Hyeon

    2015-07-01

    Cytochrome P450 (P450) and uridine 5'-diphospho-glucuronosyltransferase (UGT) are major metabolizing enzymes in the biotransformation of most drugs. Altered P450 and UGT activities are a potential cause of adverse drug-drug interaction. A method for the simultaneous evaluation of the activities of five P450s (CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A) and four UGTs (UGT1A1, UGT1A4, UGT1A9, and UGT2B7) was developed using in vitro cocktail incubation and tandem mass spectrometry. The nine probe substrates used in this assay were phenacetin (CYP1A2), diclofenac (CYP2C9), S-mephenytoin (CYP2C19), dextromethorphan (CYP2D6), midazolam (CYP3A), 7-ethyl-10-hydroxy-camptothecin (SN-38) (UGT1A1), trifluoperazine (UGT1A4), mycophenolic acid (UGT1A9), and naloxone (UGT2B7). This new method involves incubation of two cocktail doses and single cassette analysis. The two cocktail doses and the concentration of each probe substrate in vitro were determined to minimize mutual drug interactions among substrates. Cocktail A comprised phenacetin, diclofenac, S-mephenytoin, dextromethorphan, and midazolam, whereas cocktail B comprised SN-38, trifluoperazine, mycophenolic acid, and naloxone. In the incubation study of these cocktails, the reaction mixtures were pooled and simultaneously analyzed using liquid chromatography-tandem mass spectrometry. The method was validated by comparing inhibition data obtained from the incubation of each probe substrate alone with data from the cocktail method. The IC50 values obtained in both cocktail and individual incubations were in agreement with values previously reported in the literature. This cocktail method offers a rapid and robust way to simultaneously evaluate phase I and II enzyme inhibition profiles of many new chemical entities. This new method will also be useful in the drug discovery process and for advancing the mechanistic understanding of drug interactions. PMID:25904760

  9. [Inhibitory effect of imperatorin and isoimperatorin on activity of cytochrome P450 enzyme in human and rat liver microsomes].

    PubMed

    Cao, Yan; Zhong, Yu-Huan; Yuan, Mei; Li, Hua; Zhao, Chun-Jie

    2013-04-01

    Imperatorin (IM) and isoimperatorin (ISOIM) are major active components of common herbal medicines from Umbelliferae plants, and widely used in clinic. This article studies the inhibitory effect of IM and ISOIM on the activity of cytochrome P450 (CYP) enzyme, and assesses their potential drug-drug interaction. IM and ISOIM were incubated separately with human or rat liver microsomes for 30 min, with phenacetin, bupropion, tolbutamide, S-mephenytoin, dextromethorphan and midazolam as probe substrates. Metabolites of the CYP probe substrates were determined by LC-MS/MS, and IC50 values were calculated to assess the inhibitory effect of the two drugs on human CYP1A2, 2B6, 2C9, 2C19, 2D6 and 3A4 enzymes, as well as on rat CYP1A2, 2B6, 2D2 and 3A1/2, and grade their inhibitory intensity. In human liver microsomes, IM and ISOIM showed different inhibitory effects on all of the six CYP isoenzymes. They were strong inhibitors for 1A2 and 2B6. The IC50 values were 0.05 and 0.20 micromol x L(-1) for 1A2, and 0.18 and 1.07 micromol x L(-1) for 2B6, respectively. They also showed moderate inhibitory effect on 2C19, and weak effect on 2C9, 2D6 and 3A4. In rat liver microsomes, IM and ISOIM were identified as moderate inhibitors for 1A2, with IC50 values of 1.95 and 2.98 micromol x L(-1). They were moderate and weak inhibitors for 2B6, with IC50 values of 6.22 and 21.71 micromol x L(-1), respectively. They also had weaker inhibitory effect on 2D2 and 3A1/2. The results indicated that IM and ISOIM had extensive inhibitory effects on human CYP enzymes. They are strong inhibitors of CYP1 A2 and 2B6 enzymes. However, it is worth noting the interaction arising from the inhibitory effect of CYP enzymes in clinic.

  10. RS-Predictor models augmented with SMARTCyp reactivities: Robust metabolic regioselectivity predictions for nine CYP isozymes

    PubMed Central

    Zaretzki, Jed; Rydberg, Patrik; Bergeron, Charles; Bennett, Kristin P.; Olsen, Lars

    2012-01-01

    RS-Predictor is a tool for creating pathway-independent, isozyme-specific site of metabolism (SOM) prediction models using any set of known cytochrome P450 substrates and metabolites. Until now, the RS-Predictor method was only trained and validated on CYP 3A4 data, but in the present study we report on the versatility the RS-Predictor modeling paradigm by creating and testing regioselectivity models for substrates of the nine most important CYP isozymes. Through curation of source literature, we have assembled 680 substrates distributed among CYPs 1A2, 2A6, 2B6, 2C19, 2C8, 2C9, 2D6, 2E1 and 3A4, which we believe is the largest publicly accessible collection of P450 ligands and metabolites ever released. A comprehensive investigation into the importance of different descriptor classes for predicting the regioselectivity of each isozyme is made through the generation of multiple independent RS-Predictor models for each set of isozyme substrates. Two of these models include a DFT reactivity descriptor derived from SMARTCyp. Optimal combinations of RS-Predictor and SMARTCyp are shown to have stronger performance than either method alone, while also exceeding the accuracy of the commercial regioselectivity prediction methods distributed by StarDrop and Schrödinger, correctly identifying a large proportion of the metabolites in each substrate set within the top two rank-positions: 1A2(83.0%), 2A6(85.7%), 2B6(82.1%), 2C19(86.2%), 2C8(83.8%), 2C9(84.5%), 2D6(85.9%), 2E1(82.8%), 3A4(82.3%) and merged(86.0%). Comprehensive datamining of each substrate set and careful statistical analyses of the predictions made by the different models revealed new insights into molecular features that control metabolic regioselectivity and enable accurate prospective prediction of likely SOMs. PMID:22524152

  11. Effects of zedoary turmeric oil on P450 activities in rats with liver cirrhosis induced by thioacetamide.

    PubMed

    Cheng, Jing-Jing; Yang, Nai-Bin; Wu, Liang; Lin, Jia-Le; Dai, Ge-Xin; Zhu, Jia-Yin

    2014-01-01

    The aim of this study was to elucidate the effects of zedoary turmeric oil (ZTO) on P450 activities (CYP1A2, CYP2C9, CYP2C19, CYP2B6, CYP2D6 and CYP3A4) in rats with liver cirrhosis induced by thioacetamide (TAA). For the induction of liver cirrhosis, rats were given TAA in their drinking water at a concentration of 0.03% for consecutive 5 weeks and then 0.04% for the next consecutive 5 weeks throughout the establishment of cirrhosis. Then the cirrhotic rats were ip given saline, ZTO 100, 200 and 400 mg/kg, respectively, once daily for 2 weeks. When cirrhosis model was established at week 10, all rats of five groups were administered intragastrically with 15 mg/kg phenacetin, 0.6 mg/kg tolbutamide, 15 mg/kg omeprazole, 15 mg/kg bupropion, 15 mg/kg metoprolol, and 10 mg/kg midazolam. Blood samples were collected at a series of time-points and the concentrations of probe drugs in plasma were determined by HPLC-MS/MS. The degree of liver cirrhosis was assessed by HE staining. The serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) from the model group increased by approximately 4-fold, and a decreased level of albumin (Alb) was also observed, as compared to the control group (P < 0.05). However, ZTO was found to reverse those changes of serum levels observed in the model group, and the 200 mg/kg ZTO treatment group showed the most obvious reverse tendency with significantly decreased ALT, AST and increased Alb levels (P < 0.05). The results indicated that ZTO with the dose of 100 mg/kg could inhibit the activities of CYP450 isoforms CYP2C9 and CYP2D6 in vivo in cirrhotic rats induced by TAA, while ZTO with the dose of 400 mg/kg could induce the activity of CYP2C19 in vivo in cirrhotic rats induced by TAA. However, ZTO showed no influence on cirrhotic rat hepatic CYP1A2, CYP2B6 and CYP3A4 activity in vivo. This has certain guiding significance to clinical treatment.

  12. Inhibition selectivity of grapefruit juice components on human cytochromes P450.

    PubMed

    Tassaneeyakul, W; Guo, L Q; Fukuda, K; Ohta, T; Yamazoe, Y

    2000-06-15

    Five compounds including furanocoumarin monomers (bergamottin, 6', 7'-dihydroxybergamottin (DHB)), furanocoumarin dimers (4-¿¿6-hydroxy-71-¿(1-hydroxy-1-methyl)ethyl-4-methyl-6-(7-oxo-7H- furo¿3,2-g1benzopyran-4-yl)-4-hexenyl]oxy]-3,7-dimethyl- 2-octenyl]oxy]-7H-furo[3,2-g]¿1benzopyran-7-one (GF-I-1) and 4-¿¿6-hydroxy-7¿¿4-methyl-1-(1-methylethenyl)-6-(7-oxo-7H-furo¿3, 2-g1benzopyran-4-yl)-4-hexenylŏxy-3, 7-dimethyl-2-octenylŏxy-7H-furo¿3,2-g1benzopyran-7-one (GF-I-4)), and a sesquiterpene nootkatone have been isolated from grapefruit juice and screened for their inhibitory effects toward human cytochrome P450 (P450) forms using selective substrate probes. Addition of ethyl acetate extract of grapefruit juice into an incubation mixture resulted in decreased activities of CYP3A4, CYP1A2, CYP2C9, and CYP2D6. All four furanocoumarins clearly inhibited CYP3A4-catalyzed nifedipine oxidation in concentration- and time-dependent manners, suggesting that these compounds are mechanism-based inhibitors of CYP3A4. Of the furanocoumarins investigated, furanocoumarin dimers, GF-I-1 and GF-I-4, were the most potent inhibitors of CYP3A4. Inhibitor concentration required for half-maximal rate of inactivation (K(I)) values for bergamottin, DHB, GF-I-1, and GF-I-4 were calculated, respectively, as 40.00, 5. 56, 0.31, and 0.13 microM, whereas similar values were observed on their inactivation rate constant at infinite concentration of inhibitor (k(inact), 0.05-0.08 min(-1)). Apparent selectivity toward CYP3A4 does occur with the furanocoumarin dimers. In contrast, bergamottin showed rather stronger inhibitory effect on CYP1A2, CYP2C9, CYP2C19, and CYP2D6 than on CYP3A4. DHB inhibited CYP3A4 and CYP1A2 activities at nearly equivalent potencies. Among P450 forms investigated, CYP2E1 was the least sensitive to the inhibitory effect of furanocoumarin components. A sesquiterpene nootkatone has no significant effect on P450 activities investigated except for CYP2A6 and CYP2C19

  13. Clinical validity: Combinatorial pharmacogenomics predicts antidepressant responses and healthcare utilizations better than single gene phenotypes.

    PubMed

    Altar, C A; Carhart, J M; Allen, J D; Hall-Flavin, D K; Dechairo, B M; Winner, J G

    2015-10-01

    In four previous studies, a combinatorial multigene pharmacogenomic test (GeneSight) predicted those patients whose antidepressant treatment for major depressive disorder resulted in poorer efficacy and increased health-care resource utilizations. Here, we extended the analysis of clinical validity to the combined data from these studies. We also compared the outcome predictions of the combinatorial use of allelic variations in genes for four cytochrome P450 (CYP) enzymes (CYP2D6, CYP2C19, CYP2C9 and CYP1A2), the serotonin transporter (SLC6A4) and serotonin 2A receptor (HTR2A) with the outcome predictions for the very same subjects using traditional, single-gene analysis. Depression scores were measured at baseline and 8-10 weeks later for the 119 fully blinded subjects who received treatment as usual (TAU) with antidepressant standard of care, without the benefit of pharmacogenomic medication guidance. For another 96 TAU subjects, health-care utilizations were recorded in a 1-year, retrospective chart review. All subjects were genotyped after the clinical study period, and phenotype subgroups were created among those who had been prescribed a GeneSight panel medication that is a substrate for either CYP enzyme or serotonin effector protein. On the basis of medications prescribed for each subject at baseline, the combinatorial pharmacogenomic (CPGx™) GeneSight method categorized each subject into either a green ('use as directed'), yellow ('use with caution') or red category ('use with increased caution and with more frequent monitoring') phenotype, whereas the single-gene method categorized the same subjects with the traditional phenotype (for example, poor, intermediate, extensive or ultrarapid CYP metabolizer). The GeneSight combinatorial categorization approach discriminated and predicted poorer outcomes for red category patients prescribed medications metabolized by CYP2D6, CYP2C19 and CYP1A2 (P=0.0034, P=0.04 and P=0.03, respectively), whereas the single

  14. Metabolism of 7-benzyloxy-4-trifluoromethyl-coumarin by human hepatic cytochrome P450 isoforms.

    PubMed

    Renwick, A B; Surry, D; Price, R J; Lake, B G; Evans, D C

    2000-10-01

    1. The metabolism of 7-benzyloxy-4-trifluoromethylcoumarin (BFC) to 7-hydroxy-4-trifluoromethylcoumarin (HFC) was studied in human liver microsomal preparations and in cDNA-expressed human cytochrome P450 (CYP) isoforms. 2. Kinetic analysis of the NADPH-dependent metabolism of BFC to HFC in four preparations of pooled human liver microsomes revealed mean (+/- SEM) Km and Vmax of 8.3 +/- 1.3 microM and 454 +/- 98 pmol/min/mg protein respectively. 3. The metabolism of BFC to HFC was determined in a characterized bank of 24 individual human liver microsomal preparations employing BFC substrate concentrations of 20 and 50 microM (i.e. about two and six times Km respectively). With 20 microM BFC the highest correlations were observed between BFC metabolism and markers of CYP1A2 (r2 = 0.784-0.797) and then with CYP3A (r2 = 0.434-0.547) isoforms, whereas with 50 microM BFC the highest correlations were observed between BFC metabolism and markers of CYP3A (r2 = 0.679-0.837) and then with CYP1A2 (r2 = 0.421-0.427) isoforms. At both BFC substrate concentrations, lower correlations were observed between BFC metabolism and enzymatic markers for CYP2A6, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP4A9/11. 4. Using human beta-lymphoblastoid cell microsomes containing cDNA-expressed CYP isoforms, 20 microM BFC was metabolized by CYP1A2 and CYP3A4, with lower rates of metabolism being observed with CYP2C9 and CYP2C19. Kinetic studies with the CYP1A2 and CYP3A4 preparations demonstrated a lower Km with the CYP1A2 preparation, but a higher Vmax with the CYP3A4 preparation. 5. The metabolism of 20 microM BFC in human liver microsomes was inhibited to 37-48% of control by 5-100 microM of the mechanism-based CYP1A2 inhibitor furafylline and to 64-69% of control by 5-100 microM of the mechanism-based CYP3A4 inhibitor troleandomycin. While some inhibition of BFC metabolism was observed in the presence of 100 and 200 microM diethyldithiocarbamate, the addition of 2-50 micro

  15. Pharmacogenetics in Ghana: reviewing the evidence.

    PubMed

    Kudzi, W; Adjei, G O; Ofori-Adjei, D; Dodoo, A N O

    2011-06-01

    Different clinical response of different patients to the same medicine has been recognised and documented since the 1950's. Variability in response of individuals to standard doses of drug therapy is important in clinical practice and can lead to therapeutic failures or adverse drug reactions. Pharmacogenetics seeks to identify individual genetic differences (polymorphisms) in drug absorption, metabolism, distribution and excretion that can affect the activity of a particular drug with the view of improving efficacy and reducing toxicity. Although knowledge of pharmacogenetics is being translated into clinical practice in the developed world, its applicability in the developing countries is low. Several factors account for this including the fact that there is very little pharmacogenetic information available in many indigenous African populations including Ghanaians. A number of genes including Cytochrome P450 (CYP) 2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, MDR1 and TPMT have been genotyped in the Ghanaian population since the completion of the Human genome project. There is however, an urgent need to increase pharmacogenetic research in Ghana to increase availability of data. Introducing Pharmacogenetics into the curriculum of Medical and Pharmacy training institutions will influence translating knowledge of pharmacogenetics into clinical practice. This will also equip health professionals with the skill to integrate genetic information into public health decision making. PMID:21857725

  16. Present status and perspective of pharmacogenetics in Mexico.

    PubMed