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Sample records for 2c19 2d6 2e1

  1. 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

  2. Association of MDR1, CYP2D6, and CYP2C19 gene polymorphisms with prophylactic migraine treatment response.

    PubMed

    Atasayar, Gulfer; Eryilmaz, Isil Ezgi; Karli, Necdet; Egeli, Unal; Zarifoglu, Mehmet; Cecener, Gulsah; Taskapilioglu, Ozlem; Tunca, Berrin; Yildirim, Oznur; Ak, Secil; Tezcan, Gulcin; Can, Fatma Ezgi

    2016-07-15

    Prophylactic therapy response varies in migraine patients. The present study investigated the relationship between the resistance to the drugs commonly used in prophylactic therapy and the possible polymorphic variants of proteins involved in the metabolism of these drugs. Migraine patients with the MDR1 3435TT genotype exhibited a better treatment response to topiramate than migraine patients with the CC and CT genotypes (p=0.020). The MDR1 C3435T polymorphism was also found to be a higher risk factor for topiramate treatment failure in a comparison of the number of days with migraine (β2=1.152, p=0.015). However, there was no significant relationship between the treatment response to topiramate and either the CYP2D6 or CYP2C19 polymorphism, and there were no significant correlations between the treatment responses to amitriptyline, propranolol, and valproic acid and the MDR1, CYP2D6 and CYP2C19 gene polymorphisms. This is the first study to investigate the effect of the polymorphic variants on prophylactic therapy response in migraine patients. PMID:27288795

  3. Clinical Pharmacogenetics Implementation Consortium (CPIC) Guideline for CYP2D6 and CYP2C19 Genotypes and Dosing of Selective Serotonin Reuptake Inhibitors.

    PubMed

    Hicks, J K; Bishop, J R; Sangkuhl, K; Müller, D J; Ji, Y; Leckband, S G; Leeder, J S; Graham, R L; Chiulli, D L; LLerena, A; Skaar, T C; Scott, S A; Stingl, J C; Klein, T E; Caudle, K E; Gaedigk, A

    2015-08-01

    Selective serotonin reuptake inhibitors (SSRIs) are primary treatment options for major depressive and anxiety disorders. CYP2D6 and CYP2C19 polymorphisms can influence the metabolism of SSRIs, thereby affecting drug efficacy and safety. We summarize evidence from the published literature supporting these associations and provide dosing recommendations for fluvoxamine, paroxetine, citalopram, escitalopram, and sertraline based on CYP2D6 and/or CYP2C19 genotype (updates at www.pharmgkb.org). PMID:25974703

  4. No influence of the polymorphisms CYP2C19 and CYP2D6 on the efficacy of cyclophosphamide, thalidomide, and bortezomib in patients with Multiple Myeloma

    PubMed Central

    2010-01-01

    Background The response to treatment varies among patients with multiple myeloma and markers for prediction of treatment outcome are highly needed. Bioactivation of cyclophosphamide and thalidomide, and biodegradation of bortezomib, is dependent on cytochrome P450 metabolism. We explored the potential influence of different polymorphisms in the CYP enzymes on the outcome of treatment. Methods Data was analyzed from 348 patients undergoing high-dose treatment and stem cell support in Denmark in 1994 to 2004. Clinical information on relapse treatment in 243 individual patients was collected. The patients were genotyped for the non-functional alleles CYP2C19*2 and CYP2D6*3, *4, *5 (gene deletion), *6, and CYP2D6 gene duplication. Results In patients who were treated with bortezomib and were carriers of one or two defective CYP2D6 alleles there was a trend towards a better time-to-next treatment. We found no association between the number of functional CYP2C19 and CYP2D6 alleles and outcome of treatment with cyclophosphamide or thalidomide. Neither was the number of functional CYP2C19 and CYP2D6 alleles associated with neurological adverse reactions to thalidomide and bortezomib. Conclusion There was no association between functional CYP2C19 and CYP2D6 alleles and treatment outcome in multiple myeloma patients treated with cyclophosphamide, thalidomide or bortezomib. A larger number of patients treated with bortezomib are needed to determine the role of CYP2D6 alleles in treatment outcome. PMID:20684753

  5. The action of cytochrome b(5) on CYP2E1 and CYP2C19 activities requires anionic residues D58 and D65.

    PubMed

    Peng, Hwei-Ming; Auchus, Richard J

    2013-01-01

    The capacity of cytochrome b(5) (b(5)) to influence cytochrome P450 activities has been extensively studied and physiologically validated. Apo-b(5) enhances the activities of CYP3A4, CYP2A6, CYP2C19, and CYP17A1 but not that of CYP2E1 or CYP2D6, suggesting that the b(5) interaction varies among P450s. We previously showed that b(5) residues E48 and E49 are required to stimulate the 17,20-lyase activity of CYP17A1, but these same residues might not mediate b(5) activation of other P450 reactions, such as CYP2E1-catalyzed oxygenations, which are insensitive to apo-b(5). Using purified P450, b(5), and reductase (POR) in reconstituted assays, the D58G/D65G double mutation, of residues located in a hydrophilic α-helix of b(5), totally abolished the ability to stimulate CYP2E1-catalyzed chlorzoxazone 6-hydroxylation. In sharp contrast, the D58G/D65G double mutation retained the full ability to stimulate the 17,20-lyase activity of CYP17A1. The D58G/D65G double mutation competes poorly with wild-type b(5) for binding to the CYP2E1·POR complex yet accepts electrons from POR at a similar rate. Furthermore, the phospholipid composition markedly influences P450 turnover and b(5) stimulation and specificity, particularly for CYP17A1, in the following order: phosphatidylserine > phosphatidylethanolamine > phosphatidylcholine. The D58G/D65G double mutation also failed to stimulate CYP2C19-catalyzed (S)-mephenytoin 4-hydroxylation, whereas the E48G/E49G double mutation stimulated these activities of CYP2C19 and CYP2E1 equivalent to wild-type b(5). We conclude that b(5) residues D58 and D65 are essential for the stimulation of CYP2E1 and CYP2C19 activities and that the phospholipid composition significantly influences the b(5)-P450 interaction. At least two surfaces of b(5) differentially influence P450 activities, and the critical residues for individual P450 reactions cannot be predicted from sensitivity to apo-b(5) alone. PMID:23193974

  6. The action of cytochrome b5 on both CYP2E1 and CYP2C19 activities requires the anionic residues D58 and D65

    PubMed Central

    Peng, Hwei-Ming; Auchus, Richard J.

    2013-01-01

    The capacity of cytochrome b5 (b5) to influence cytochrome P450 activities has been extensively studied and physiologically validated. Apo-b5 enhances the activities of CYP3A4, CYP2A6, CYP2C19, and CYP17A1 but not of CYP2E1 or CYP2D6, suggesting that the b5 interaction varies amongst P450s. We previously showed that b5 residues E48 and E49 are required to stimulate the 17,20-lyase activity of CYP17A1, but these same residues might not mediate b5 activation of other P450 reactions, such as CYP2E1-catalyzed oxygenations, which are insensitive to apo-b5. Using purified P450, b5, and reductase (POR) in reconstituted assays, mutation D58G+D65G, residues located in a hydrophilic α-helix of b5, totally abolished the ability to stimulate CYP2E1-catalyzed chlorzoxazone 6-hydroxylation. In sharp contrast, the D58G+D65G mutation retained full capability to stimulate the 17,20 lyase activity of CYP17A1. Mutation D58G+D65G competes poorly with wild-type b5 for binding to the CYP2E1•POR complex yet accepts electrons from POR at a similar rate. Furthermore, the phospholipid composition markedly influences P450 turnover and b5 stimulation and specificity, particularly for CYP17A1, in the order phosphatidylserine > phosphatidylethanolamine > phosphatidylcholine. Mutation D58G+D65G also failed to stimulate CYP2C19-catalyzed (S)-mephenytoin 4-hydroxylation, whereas mutation E48G+E49G stimulated these activities of CYP2C19 and CYP2E1 equivalent to wild-type b5. We conclude that b5 residues D58 and D65 are essential for the stimulation of CYP2E1 and CYP2C19 activities and that phospholipid composition significantly influences the b5-P450 interaction. At least two surfaces of b5 differentially influence P450 activities, and the critical residues for individual P450 reactions cannot be predicted from sensitivity to apo-b5 alone. PMID:23193974

  7. CYP2D6 and CYP2C19 genotypes of patients with terodiline cardiotoxicity identified through the yellow card system

    PubMed Central

    Ford, Gary A; Wood, Susan M; Daly, Ann K

    2000-01-01

    Aims Terodiline has concentration dependent QT prolonging effects and thus the potential for cardiotoxicity. Pharmacogenetic variation in terodiline metabolism could be responsible for cardiotoxicity. We sought to determine whether CYP2D6 (debrisoquine hydroxylase) or CYP2C19 (S-mephenytoin hydroxylase) status is a risk factor for terodiline cardiotoxicity. Methods Using the UK Yellow Card scheme to identify patients, blood samples were obtained from eight patients who survived ventricular tachycardia or torsades de pointes suspected to be due to terodiline, for determination of CYP2D6 and CYP2C19 genotypes. Genotype prevalence was compared with that in published general population groups. Results One patient was a CYP2D6 poor metaboliser (CYP2D6*4 homozygous) and a second was heterozygous for CYP2D6*4, a slightly lower frequency for these genotypes compared with the general population (P = 0.31). In the case of CYP2C19, one patient was a poor metaboliser and four were heterozygous for the variant CYP2C19*2 allele, compared with general population frequencies of 2% and 23%, respectively (P = 0.035). Conclusions These findings suggest that debrisoquine poor metaboliser status is not primarily responsible for terodiline cardiotoxicity. However, possession of the CYP2C19*2 allele appears to contribute to adverse cardiac reactions to terodiline. The present study demonstrates the feasibility of using spontaneous adverse drug reaction reporting schemes to determine the contribution of genotype for metabolizing enzymes to uncommon adverse drug reactions. PMID:10886124

  8. Genetic polymorphisms of CYP2D6, CYP1A1 and CYP2E1 in the South-Amerindian population of Chile.

    PubMed

    Muñoz, S; Vollrath, V; Vallejos, M P; Miquel, J F; Covarrubias, C; Raddatz, A; Chianale, J

    1998-08-01

    Polymorphisms of cytochrome P450 genes show pronounced interethnic variation and have not been previously studied in the South-Amerindian population, which probably has an Asian origin. Therefore, a similar distribution of allelic and haplotype frequencies of cytochrome P450 genes to Asian populations might be expected in South-Amerindians. We analysed the allelic frequencies and haplotype distribution for CYP2D6, CYP1A1 and CYP2E1 genes in the South-Amerindian population of Chile (Mapuche, n = 84) by Southern blot or polymerase chain reaction-restriction fragment length polymorphism. Similar allelic frequencies and haplotype distribution for the CYP2E1 gene between Mapuches and Asian populations were observed. Frequencies of the two major functional CYP2D6*1 and CYP2D6*2 alleles and the CYP2D6*5 null allele were similar to most populations world-wide. The alleles CYP2D6*3 and *9, absent in Asians, were not found in Mapuches. The CYP2D6*4 allelic group, uncommon in Asian populations, had a low frequency in Mapuches (0.036). However, the CYP2D6*10 allele (Ch1, Ch2 and J), highly frequent in Asians (0.33-0.50), had a very low frequency (0.018) in our study population. In addition, the presence of the common Chinese 44 kb XbaI fragment of CYP2D6 (0.19-0.31 in Asians) was not detected in South-Amerindians. Interestingly, high frequencies for the rare m2 and Val alleles of the CYP1A1 gene were found in Mapuches (0.821 and 0.91, respectively), and the rare Val/m2 haplotype was significantly higher in Mapuches (0.748) than in Asians (0.24) (P < 0.01). The frequency of this haplotype in Mapuches is the highest frequency reported to date. The population studied was in Hardy-Weinberg equilibrium for these polymorphisms. The major differences between Mapuches and Asians were for CYP2D6*10 and CYP1A1 allelic frequencies, as well as the absence of the common Chinese 44 kb XbaI fragment of CYP2D6. These differences might be interpreted as a consequence of genetic drifts caused

  9. The effects of H2S on the activities of CYP2B6, CYP2D6, CYP3A4, CYP2C19 and CYP2C9 in vivo in rat.

    PubMed

    Wang, Xianqin; Han, Anyue; Wen, Congcong; Chen, Mengchun; Chen, Xinxin; Yang, Xuezhi; Ma, Jianshe; Lin, Guanyang

    2013-01-01

    Hydrogen sulfide (H2S) is a colorless, flammable, extremely hazardous gas with a "rotten egg" smell. The human body produces small amounts of H2S and uses it as a signaling molecule. The cocktail method was used to evaluate the influence of H2S on the activities of CYP450 in rats, which were reflected by the changes of pharmacokinetic parameters of five specific probe drugs: bupropion, metroprolol, midazolam, omeprazole and tolbutamide, respectively. The rats were randomly divided into two groups, control group and H2S group. The H2S group rats were given 5 mg/kg NaHS by oral administration once a day for seven days. The mixture of five probes was given to rats through oral administration and the blood samples were obtained at a series of time-points through the caudal vein. The concentrations of probe drugs in rat plasma were measured by LC-MS. In comparing the H2S group with the control group, there was a statistically pharmacokinetics difference for midazolam and tolbutamide; the area under the plasma concentration-time curve (AUC) was decreased for midazolam (p < 0.05) and increased for tolbutamide (p < 0.05); while there was no statistical pharmacokinetics difference for bupropion, metroprolol and omeprazole. H2S could not influence the activities of CYP2B6, CYP2D6 and CYP2C19 in rats, while H2S could induce the activity of CYP3A4 and inhibit the activity of CYP2C9 in rats. PMID:24336065

  10. The Effects of H2S on the Activities of CYP2B6, CYP2D6, CYP3A4, CYP2C19 and CYP2C9 in Vivo in Rat

    PubMed Central

    Wang, Xianqin; Han, Anyue; Wen, Congcong; Chen, Mengchun; Chen, Xinxin; Yang, Xuezhi; Ma, Jianshe; Lin, Guanyang

    2013-01-01

    Hydrogen sulfide (H2S) is a colorless, flammable, extremely hazardous gas with a “rotten egg” smell. The human body produces small amounts of H2S and uses it as a signaling molecule. The cocktail method was used to evaluate the influence of H2S on the activities of CYP450 in rats, which were reflected by the changes of pharmacokinetic parameters of five specific probe drugs: bupropion, metroprolol, midazolam, omeprazole and tolbutamide, respectively. The rats were randomly divided into two groups, control group and H2S group. The H2S group rats were given 5 mg/kg NaHS by oral administration once a day for seven days. The mixture of five probes was given to rats through oral administration and the blood samples were obtained at a series of time-points through the caudal vein. The concentrations of probe drugs in rat plasma were measured by LC-MS. In comparing the H2S group with the control group, there was a statistically pharmacokinetics difference for midazolam and tolbutamide; the area under the plasma concentration-time curve (AUC) was decreased for midazolam (p < 0.05) and increased for tolbutamide (p < 0.05); while there was no statistical pharmacokinetics difference for bupropion, metroprolol and omeprazole. H2S could not influence the activities of CYP2B6, CYP2D6 and CYP2C19 in rats, while H2S could induce the activity of CYP3A4 and inhibit the activity of CYP2C9 in rats. PMID:24336065

  11. 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

  12. 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

    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

  13. Association between CYP2C19*17 and metabolism of amitriptyline, citalopram and clomipramine in Dutch hospitalized patients.

    PubMed

    de Vos, A; van der Weide, J; Loovers, H M

    2011-10-01

    Polymorphisms in genes coding for drug metabolizing enzymes, such as the cytochrome P450 enzymes CYP2C19 and CYP2D6, can lead to therapy failure and side effects. In earlier studies, the novel variant CYP2C19*17 increased metabolism of several CYP2C19 substrates. The objective of this study was to evaluate the impact of CYP2C19*17 on the metabolism of amitriptyline (AT), citalopram (CIT), and clomipramine (CLOM). Six-hundred and seventy-eight patients were included in this study, based on availability of DNA and serum levels of parent drug and main metabolite. We investigated the relationship between CYP2C19 genotypes and metabolic parameters, including serum levels corrected for dose and metabolic ratio (MR). The CYP2C19*17 allele was significantly associated with decreased MR for CIT (CYP2C19*1/*17 mean MR=2.3, compared with CYP2C19*1/*1 mean MR=2.8) and AT (CYP2C19*17/*17 mean MR=0.8, compared with CYP2C19*1/*1 mean MR=3.7 in the CYP2D6*1/*1 subgroup). Furthermore, significant association of CYP2D6 genotype with AT, CIT, and CLOM metabolism was observed. No clear correlation was found between CYP2C19 genotype and CLOM metabolism. This study confirms the increased activity of the CYP2C19*17 allele and shows increased metabolism of drugs that are metabolized by CYP2C19, including AT and CIT. However, the clinical relevance of CYP2C19*17 is probably limited for AT, CIT, and CLOM. PMID:20531370

  14. Cyp2D6 catalyzes 5-hydroxylation of 1-(2-pyrimidinyl)-piperazine, an active metabolite of several psychoactive drugs, in human liver microsomes.

    PubMed

    Raghavan, Nirmala; Zhang, Donglu; Zhu, Mingshe; Zeng, Jianing; Christopher, Lisa

    2005-02-01

    1-(2-Pyrimidinyl)-piperazine (1-PP) is an active metabolite of several psychoactive drugs including buspirone. 1-PP is also the major metabolite in the human circulation and in rat brains following oral administration of buspirone. This study was conducted to identify the enzyme responsible for the metabolic conversion of 1-PP to 5-hydroxy-1-(2-pyrimidinyl)-piperazine (HO-1-PP) in human liver microsomes (HLMs). The product HO-1-PP was quantified by a validated liquid chromatography-tandem mass spectrometry method. In the presence of NADPH, 1-PP (100 microM) was incubated separately with human cDNA-expressed cytochrome P450 isozymes (including CYP2D6, 3A4, 1A2, 2A6, 2C9, 2C19, 2E1, and 2B6) at 37 degrees C. CYP2D6 catalyzed the formation of HO-1-PP from 1-PP. This catalytic activity was >95% inhibited by quinidine, a CYP2D6 inhibitor. HO-1-PP formation rates correlated well with the bufuralol 1-hydroxylase (CYP2D6) activities of individual HLMs. The formation of HO-1-PP followed a Michaelis-Menten kinetics with a K(m) of 171 microM and V(max) of 313 pmol/min x mg protein in HLMs. Collectively, these results indicate that polymorphic CYP2D6 is responsible for the conversion of 1-PP to HO-1-PP. PMID:15507542

  15. METOCLOPRAMIDE IS METABOLIZED BY CYP2D6 AND IS A REVERSIBLE INHIBITOR, BUT NOT INACTIVATOR, OF CYP2D6

    PubMed Central

    Nagy, Leslie D.; Fujiwara, Rina; Furge, Laura Lowe

    2014-01-01

    Metoclopramide is a widely used clinical drug in a variety of medical settings with rare acute dystonic events reported. The aim of this study was to assess a previous report of inactivation of CYP2D6 by metoclopramide, to determine the contribution of various CYPs to metoclopramide metabolism, and to identify the mono-oxygenated products of metoclopramide metabolism. Metoclopramide interacted with CYP2D6 with Type I binding and a Ks value of 9.56 ± 1.09 μM. CYP2D6 was the major metabolizer of metoclopramide and the two major products were N-deethylation of the diethyl amine and N-hydroxylation on the phenyl ring amine. CYPs 1A2, 2C9, 2C19, and 3A4 also metabolized metoclopramide. While reversible inhibition of CYP2D6 was noted, CYP2D6 inactivation by metoclopramide was not observed under conditions of varying concentration or varying time using Supersomes™ or pool human liver microsomes. The major metabolites of metoclopramide were N-hydroxylation and N-deethylation formed most efficiently by CYP2D6 but also formed by all CYPs examined. Also, while metoclopramide is metabolized primarily by CYP2D6, it is not a mechanism-based inactivator of CYP2D6 in vitro. PMID:24010633

  16. Metoclopramide is metabolized by CYP2D6 and is a reversible inhibitor, but not inactivator, of CYP2D6.

    PubMed

    Livezey, Mara R; Briggs, Erran D; Bolles, Amanda K; Nagy, Leslie D; Fujiwara, Rina; Furge, Laura Lowe

    2014-04-01

    1. Metoclopramide is a widely used clinical drug in a variety of medical settings with rare acute dystonic events reported. The aim of this study was to assess a previous report of inactivation of CYP2D6 by metoclopramide, to determine the contribution of various CYPs to metoclopramide metabolism, and to identify the mono-oxygenated products of metoclopramide metabolism. 2. Metoclopramide interacted with CYP2D6 with Type I binding and a Ks value of 9.56 ± 1.09 µM. CYP2D6 was the major metabolizer of metoclopramide and the two major products were N-deethylation of the diethyl amine and N-hydroxylation on the phenyl ring amine. CYPs 1A2, 2C9, 2C19, and 3A4 also metabolized metoclopramide. 3. While reversible inhibition of CYP2D6 was noted, CYP2D6 inactivation by metoclopramide was not observed under conditions of varying concentration or varying time using Supersomes(TM) or pooled human liver microsomes. 4. The major metabolites of metoclopramide were N-hydroxylation and N-deethylation formed most efficiently by CYP2D6 but also formed by all CYPs examined. Also, while metoclopramide is metabolized primarily by CYP2D6, it is not a mechanism-based inactivator of CYP2D6 in vitro. PMID:24010633

  17. 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

  18. Chronic administration of caderofloxacin, a new fluoroquinolone, increases hepatic CYP2E1 expression and activity in rats

    PubMed Central

    Liu, Li; Miao, Ming-xing; Zhong, Ze-yu; Xu, Ping; Chen, Yang; Liu, Xiao-dong

    2016-01-01

    Aim: Caderofloxacin is a new fluoroquinolone that is under phase III clinical trials in China. Here we examined the effects of caderofloxacin on rat hepatic cytochrome P450 (CYP450) isoforms as well as the potential of caderofloxacin interacting with co-administered drugs. Methods: Male rats were treated with caderofloxacin (9 mg/kg, ig) once or twice daily for 14 consecutive days. The effects of caderofloxacin on CYP3A, 2D6, 2C19, 1A2, 2E1 and 2C9 were evaluated using a “cocktail” of 6 probes (midazolam, dextromethorphan, omeprazole, theophylline, chlorzoxazone and diclofenac) injected on d 0 (prior to caderofloxacin exposure) and d 15 (after caderofloxacin exposure). Hepatic microsomes from the caderofloxacin-treated rats were used to assess CYP2E1 activity and chlorzoxazone metabolism. The expression of CYP2E1 mRNA and protein in hepatic microsomes was analyzed with RT-PCR and Western blotting, respectively. Results: Fourteen-day administration of caderofloxacin significantly increased the activity of hepatic CYP2E1, leading to enhanced metabolism of chlorzoxazone. In vitro microsomal study confirmed that CYP2E1 was a major metabolic enzyme involved in chlorzoxazone metabolism, and the 14-d administration of caderofloxacin significantly increased the activity of CYP2E1 in hepatic microsomes, resulting in increased formation of 6-hydroxychlorzoxazone. Furthermore, the 14-d administration of caderofloxacin significantly increased the expression of CYP2E1 mRNA and protein in liver microsomes, which was consistent with the pharmacokinetic results. Conclusion: Fourteen-day administration of caderofloxacin can induce the expression and activity of hepatic CYP2E1 in rats. When caderofloxacin is administered, a potential drug-drug interaction mediated by CYP2E1 induction should be considered. PMID:26838075

  19. 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. PMID:25681130

  20. 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. PMID:18034311

  1. 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.

  2. 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

  3. CYP2D6 polymorphism in patients with eating disorders.

    PubMed

    Peñas-Lledó, E M; Dorado, P; Agüera, Z; Gratacós, M; Estivill, X; Fernández-Aranda, F; Llerena, A

    2012-04-01

    CYP2D6 polymorphism is associated with variability in drug response, endogenous metabolism (that is, serotonin), personality, neurocognition and psychopathology. The relationship between CYP2D6 genetic polymorphism and the risk of eating disorders (ED) was analyzed in 267 patients with ED and in 285 controls. A difference in the CYP2D6 active allele distribution was found between these groups. Women carrying more than two active genes (ultrarapid metabolizers) (7.5 vs 4.6%) or two (67 vs 58.9%) active genes were more frequent among patients with ED, whereas those with one (20.6 vs 30.2%) or zero active genes (4.9 vs 6.3%) were more frequent among controls (P<0.05). Although further research is needed, present findings suggest an association between CYP2D6 and ED. CYP2D6 allele distribution in patients with ED seems related to increased enzyme activity. PMID:20877302

  4. Differential CYP 2D6 Metabolism Alters Primaquine Pharmacokinetics

    PubMed Central

    Potter, Brittney M. J.; Xie, Lisa H.; Vuong, Chau; Zhang, Jing; Zhang, Ping; Duan, Dehui; Luong, Thu-Lan T.; Bandara Herath, H. M. T.; Dhammika Nanayakkara, N. P.; Tekwani, Babu L.; Walker, Larry A.; Nolan, Christina K.; Sciotti, Richard J.; Zottig, Victor E.; Smith, Philip L.; Paris, Robert M.; Read, Lisa T.; Li, Qigui; Pybus, Brandon S.; Sousa, Jason C.; Reichard, Gregory A.

    2015-01-01

    Primaquine (PQ) metabolism by the cytochrome P450 (CYP) 2D family of enzymes is required for antimalarial activity in both humans (2D6) and mice (2D). Human CYP 2D6 is highly polymorphic, and decreased CYP 2D6 enzyme activity has been linked to decreased PQ antimalarial activity. Despite the importance of CYP 2D metabolism in PQ efficacy, the exact role that these enzymes play in PQ metabolism and pharmacokinetics has not been extensively studied in vivo. In this study, a series of PQ pharmacokinetic experiments were conducted in mice with differential CYP 2D metabolism characteristics, including wild-type (WT), CYP 2D knockout (KO), and humanized CYP 2D6 (KO/knock-in [KO/KI]) mice. Plasma and liver pharmacokinetic profiles from a single PQ dose (20 mg/kg of body weight) differed significantly among the strains for PQ and carboxy-PQ. Additionally, due to the suspected role of phenolic metabolites in PQ efficacy, these were probed using reference standards. Levels of phenolic metabolites were highest in mice capable of metabolizing CYP 2D6 substrates (WT and KO/KI 2D6 mice). PQ phenolic metabolites were present in different quantities in the two strains, illustrating species-specific differences in PQ metabolism between the human and mouse enzymes. Taking the data together, this report furthers understanding of PQ pharmacokinetics in the context of differential CYP 2D metabolism and has important implications for PQ administration in humans with different levels of CYP 2D6 enzyme activity. PMID:25645856

  5. 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

  6. 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

  7. 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

  8. Identification of CYP2C19 inhibitors from phytochemicals using the recombinant human enzyme model.

    PubMed

    Kong, L M; Xu, S Y; Hu, H H; Zhou, H; Jiang, H D; Yu, L S; Zeng, S

    2014-05-01

    The aim of the present study was to develop the recombinant insect cell-expressed protein as an in vitro model for inhibitors screening for human cytochrome P450 2C19 (CYP2C19), and to use the model to investigate the inhibition effect of three phytochemicals on CYP2C19 in vitro. Omeprazole was applied as the probe substrate. The estimated inhibitory constant (K(i)) of ticlopidine and fluvoxamine were 0.64 +/- 0.025 microM and 0.29 +/- 0.090 microM, respectively. After co-incubation with ticlopidine or fluvoxamine, the mean omeprazole Michaelis-Menten constant (K(m)) increased from 4.99 +/- 0.22 microM to 16.25 +/- 1.22 microM or 19.20 +/- 1.73 microM, respectively, while omeprazole's mean V(max) did not vary much. Both ticlopidine and fluvoxamine were competitive inhibitors of CYP2C19. The IC50 of three phytochemicals, isoalantolactone, curcumol and schisandrin A was determined as 38.91 microM, 121.0 microM and 86.41 microM, and the K(i) as 5.02 +/- 1.04 microM, 35.84 +/- 8.95 microM, and 4.46 +/- 0.017 microM, respectively. The in vitro model for inhibitor screening established using recombinant CYP2C19 could be used to assess the inhibition potential of drug candidates. Isoalantolactone and schisandrin A are potent inhibitors of CYP2C19, while curcumol is a moderate potent inhibitor of CYP2C19. PMID:24855828

  9. 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

  10. Clinical Application of CYP2C19 Pharmacogenetics Toward More Personalized Medicine

    PubMed Central

    Lee, Su-Jun

    2013-01-01

    More than 30 years of genetic research on the CYP2C19 gene alone has identified approximately 2,000 reference single nucleotide polymorphisms (rsSNPs) containing 28 registered alleles in the P450 Allele Nomenclature Committee and the number continues to increase. However, knowledge of CYP2C19 SNPs remains limited with respect to biological functions. Functional information on the variant is essential for justifying its clinical use. Only common variants (minor allele frequency >5%) that represent CYP2C19*2, *3, *17, and others have been mostly studied. Discovery of new genetic variants is outstripping the generation of knowledge on the biological meanings of existing variants. Alternative strategies may be needed to fill this gap. The present study summarizes up-to-date knowledge on functional CYP2C19 variants discovered in phenotyped humans studied at the molecular level in vitro. Understanding the functional meanings of CYP2C19 variants is an essential step toward shifting the current medical paradigm to highly personalized therapeutic regimens. PMID:23378847

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

    ClinicalTrials.gov

    2015-12-09

    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

  12. The Pharmacogenetic Control of Antiplatelet Response: Candidate Genes and CYP2C19

    PubMed Central

    Yang, Yao; Lewis, Joshua P.; Hulot, Jean-Sébastien; Scott, Stuart A.

    2016-01-01

    Introduction Aspirin, clopidogrel, prasugrel and ticagrelor are antiplatelet agents for the prevention of ischemic events in patients with acute coronary syndromes (ACS), percutaneous coronary intervention (PCI), and other indications. Variability in response is observed to different degrees with these agents, which can translate to increased risks for adverse cardiovascular events. As such, potential pharmacogenetic determinants of antiplatelet pharmacokinetics, pharmacodynamics and clinical outcomes have been actively studied. Areas covered This article provides an overview of the available antiplatelet pharmacogenetics literature. Evidence supporting the significance of candidate genes and their potential influence on antiplatelet response and clinical outcomes are summarized and evaluated. Additional focus is directed at CYP2C19 and clopidogrel response, including the availability of clinical testing and genotype-directed antiplatelet therapy. Expert opinion The reported aspirin response candidate genes have not been adequately replicated and few candidate genes have thus far been implicated in prasugrel or ticagrelor response. However, abundant data supports the clinical validity of CYP2C19 and clopidogrel response variability among ACS/PCI patients. Although limited prospective trial data are available to support the utility of routine CYP2C19 testing, the increased risks for reduced clopidogrel efficacy among ACS/PCI patients that carry CYP2C19 loss-of-function alleles should be considered when genotype results are available. PMID:26173871

  13. 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. PMID:17600081

  14. 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

  15. Substituted Imidazole of 5-Fluoro-2-[4-[(2-phenyl-1H-imidazol-5-yl)methyl]-1-piperazinyl]pyrimidine Inactivates Cytochrome P450 2D6 by Protein Adduction

    PubMed Central

    Nagy, Leslie D.; Mocny, Catherine S.; Diffenderfer, Laura E.; Hsi, David J.; Butler, Brendan F.; Arthur, Evan J.; Fletke, Kyle J.; Palamanda, Jairam R.; Nomeir, Amin A.

    2011-01-01

    5-Fluoro-2-[4-[(2-phenyl-1H-imidazol-5-yl)methyl]-1-piperazinyl]pyrimidine (SCH 66712) is a potent mechanism-based inactivator of human cytochrome P450 2D6 that displays type I binding spectra with a Ks of 0.39 ± 0.10 μM. The partition ratio is ∼3, indicating potent inactivation that addition of exogenous nucleophiles does not prevent. Within 15 min of incubation with SCH 66712 and NADPH, ∼90% of CYP2D6 activity is lost with only ∼20% loss in ability to bind CO and ∼25% loss of native heme over the same time. The stoichiometry of binding to the protein was 1.2:1. SDS-polyacrylamide gel electrophoresis with Western blotting and autoradiography analyses of CYP2D6 after incubations with radiolabeled SCH 66712 further support the presence of a protein adduct. Metabolites of SCH 66712 detected by mass spectrometry indicate that the phenyl group on the imidazole ring of SCH 66712 is one site of oxidation by CYP2D6 and could lead to methylene quinone formation. Three other metabolites were also observed. For understanding the metabolic pathway that leads to CYP2D6 inactivation, metabolism studies with CYP2C9 and CYP2C19 were performed because neither of these enzymes is significantly inhibited by SCH 66712. The metabolites formed by CYP2C9 and CYP2C19 are the same as those seen with CYP2D6, although in different abundance. Modeling studies with CYP2D6 revealed potential roles of various active site residues in the oxidation of SCH 66712 and inactivation of CYP2D6 and showed that the phenyl group of SCH 66712 is positioned at 2.2 Å from the heme iron. PMID:21422192

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

    PubMed

    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

  18. CYP2C19*17 genetic polymorphism--an uncommon cause of voriconazole treatment failure.

    PubMed

    Abidi, Maheen Z; D'Souza, Anita; Kuppalli, Krutika; Ledeboer, Nathan; Hari, Parmeswaran

    2015-09-01

    We describe an immunosuppressed, 48-year-old male, allogeneic hematopoietic stem cell transplant recipient with severe graft-versus-host disease who developed invasive pulmonary Aspergillus fumigatus infection 6 months after transplant. His lack of response to voriconazole and undetectable serum trough levels of the drug led us to establish that he had the uncommon cytochrome P450, CYP2C19*17 allele, which leads to a rapid metabolism of voriconazole but not of the other azole antifungals. We discuss the particular challenges encountered in this case. PMID:25986028

  19. 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

  20. CYP2C19 polymorphisms and therapeutic drug monitoring of voriconazole: are we ready for clinical implementation of pharmacogenomics?

    PubMed

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

    2014-07-01

    Since its approval by the U.S. 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

  1. 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

  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. 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

  4. 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

  5. CYP2C19 inhibition: the impact of substrate probe selection on in vitro inhibition profiles.

    PubMed

    Foti, Robert S; Wahlstrom, Jan L

    2008-03-01

    Understanding the potential for cytochrome P450 (P450)-mediated drug-drug interactions is a critical part of the drug discovery process. Factors such as nonspecific binding, atypical kinetics, poor effector solubility, and varying ratios of accessory proteins may alter the kinetic behavior of an enzyme and subsequently confound the extrapolation of in vitro data to the human situation. The architecture of the P450 active site and the presence of multiple binding regions within the active site may also confound in vitro-in vivo extrapolation, as inhibition profiles may be dependent on a specific inhibitor-substrate interaction. In these studies, the inhibition profiles of a set of 24 inhibitors were paneled against the CYP2C19 substrate probes (S)-mephenytoin, (R)-omeprazole, (S)-omeprazole, and (S)-fluoxetine, on the basis of their inclusion in recent U.S. Food and Drug Administration guidance for in vitro drug-drug interactions with CYP2C19. (S)-Mephenytoin was inhibited an average of 5.6-fold more potently than (R)- or (S)-omeprazole and 9.2-fold more potently than (S)-fluoxetine. Hierarchical clustering of the inhibition data suggested three substrate probe groupings, with (S)-mephenytoin exhibiting the largest difference from the rest of the substrate probes, (S)-fluoxetine exhibiting less difference from (S)-mephenytoin and the omeprazoles and (R)- and (S)-omeprazole exhibiting minimal differences from each other. Predictions of in vivo inhibition potency based on the in vitro data suggest that most drug-drug interactions will be identified by either (S)-mephenytoin or omeprazole, although the expected magnitude of the interaction may vary depending on the chosen substrate probe. PMID:18048485

  6. Routine Screening for CYP2C19 Polymorphisms for Patients being Treated with Clopidogrel is not Recommended

    PubMed Central

    Hong, Robert A; Khan, Zia R; Valentin, Mona R; Badawi, Ramy A

    2015-01-01

    Recent efforts directed at potential litigation in Hawai‘i have resulted in a renewed interest for genetic screening for cytochrome P450 2C19 (CYP2C19) polymorphisms in patients treated with clopidogrel. Clopidogrel is an antiplatelet agent, frequently used in combination with aspirin, for the prevention of thrombotic complications with acute coronary syndrome and in patients undergoing percutaneous coronary interventions. Cytochrome P-450 (CYP) 2C19 is an enzyme involved in the bioactivation of clopidogrel from a pro-drug to an active inhibitor of platelet action. Patients of Asian and Pacific Island background have been reported to have an increase in CYP2C19 polymorphisms associated with loss-of-function of this enzyme when compared to other ethnicities. This has created an interest in genetic testing for CYP2C19 polymorphisms in Hawai‘i. Based upon our review of the current literature, we do not feel that there is support for the routine screening for CYP2C19 polymorphisms in patients being treated with clopidogrel; furthermore, the results of genetic testing may not be helpful in guiding therapeutic decisions. We recommend that decisions on the type of antiplatelet treatment be made based upon clinical evidence of potential differential outcomes associated with the use of these agents rather than on the basis of genetic testing. PMID:25628978

  7. 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

  8. Optimizing clopidogrel dose response: a new clinical algorithm comprising CYP2C19 pharmacogenetics and drug interactions

    PubMed Central

    Saab, Yolande B; Zeenny, Rony; Ramadan, Wijdan H

    2015-01-01

    Purpose Response to clopidogrel varies widely with nonresponse rates ranging from 4% to 30%. A reduced function of the gene variant of the CYP2C19 has been associated with lower drug metabolite levels, and hence diminished platelet inhibition. Drugs that alter CYP2C19 activity may also mimic genetic variants. The aim of the study is to investigate the cumulative effect of CYP2C19 gene polymorphisms and drug interactions that affects clopidogrel dosing, and apply it into a new clinical-pharmacogenetic algorithm that can be used by clinicians in optimizing clopidogrel-based treatment. Method Clopidogrel dose optimization was analyzed based on two main parameters that affect clopidogrel metabolite area under the curve: different CYP2C19 genotypes and concomitant drug intake. Clopidogrel adjusted dose was computed based on area under the curve ratios for different CYP2C19 genotypes when a drug interacting with CYP2C19 is added to clopidogrel treatment. A clinical-pharmacogenetic algorithm was developed based on whether clopidogrel shows 1) expected effect as per indication, 2) little or no effect, or 3) clinical features that patients experience and fit with clopidogrel adverse drug reactions. Results The study results show that all patients under clopidogrel treatment, whose genotypes are different from *1*1, and concomitantly taking other drugs metabolized by CYP2C19 require clopidogrel dose adjustment. To get a therapeutic effect and avoid adverse drug reactions, therapeutic dose of 75 mg clopidogrel, for example, should be lowered to 6 mg or increased to 215 mg in patients with different genotypes. Conclusion The implementation of clopidogrel new algorithm has the potential to maximize the benefit of clopidogrel pharmacological therapy. Clinicians would be able to personalize treatment to enhance efficacy and limit toxicity. PMID:26445541

  9. Sex differences in the impact of CYP2C19 polymorphisms and low-grade inflammation on coronary microvascular disorder.

    PubMed

    Akasaka, Tomonori; Hokimoto, Seiji; Sueta, Daisuke; Tabata, Noriaki; Sakamoto, Kenji; Yamamoto, Eiichiro; Yamamuro, Megumi; Tsujita, Kenichi; Kojima, Sunao; Kaikita, Koichi; Kajiwara, Ayami; Morita, Kazunori; Oniki, Kentaro; Saruwatari, Junji; Nakagawa, Kazuko; Ogata, Yasuhiro; Ogawa, Hisao

    2016-06-01

    Categorization as a cytochrome P-450 (CYP) 2C19 poor metabolizer (PM) is reported to be an independent risk factor for cardiovascular disease. It is correlated with an increase in the circulating levels of high-sense C-reactive protein (hs-CRP) in women only, although its role in coronary microcirculation is unclear. We examined sex differences in the impact of the CYP2C19 genotype and low-grade inflammation on coronary microvascular disorder (CMVD). We examined CYP2C19 genotypes in patients with CMVD (n = 81) and in healthy subjects as control (n = 81). CMVD was defined as the absence of coronary artery stenosis and epicardial spasms, the presence of inverted lactic acid levels between the intracoronary and coronary sinuses, or an adenosine triphosphate-induced coronary flow reserve ratio < 2.5. CYP2C19 PMs have two loss-of-function (LOF) alleles (*2, *3). Extensive metabolizers have no LOF alleles, and intermediate metabolizers have one LOF allele. The ratio of CYP2C19 PM and hs-CRP levels in CMVD was significantly higher than that of controls, especially in women (40.9 vs. 13.8%, P = 0.013; 0.11 ± 0.06 vs. 0.07 ± 0.04 mg/dl, P = 0.001). Moreover, in each CYP2C19 genotype, hs-CRP levels in CMVD in CYP2C19 PMs were significantly higher than those of the controls, especially in women (0.15 ± 0.06 vs. 0.07 ± 0.03, P = 0.004). Multivariate analysis for CMVD indicated that the female sex, current smoking, and hypertension were predictive factors, and that high levels of hs-CRP and CYP2C19 PM were predictive factors in women only (odds ratio 3.5, 95% confidence interval 1.26-9.93, P = 0.033; odds ratio 4.1, 95% confidence interval 1.15-14.1, P = 0.038). CYP2C19 PM genotype may be a new candidate risk factor for CMVD via inflammation exclusively in the female population. PMID:26993229

  10. Coprescription of Tamoxifen and Medications That Inhibit CYP2D6

    PubMed Central

    Sideras, Kostandinos; Ingle, James N.; Ames, Matthew M.; Loprinzi, Charles L.; Mrazek, David P.; Black, John L.; Weinshilboum, Richard M.; Hawse, John R.; Spelsberg, Thomas C.; Goetz, Matthew P.

    2010-01-01

    Evidence has emerged that the clinical benefit of tamoxifen is related to the functional status of the hepatic metabolizing enzyme cytochrome P450 2D6 (CYP2D6). CYP2D6 is the key enzyme responsible for the generation of the potent tamoxifen metabolite, endoxifen. Multiple studies have examined the relationship of CYP2D6 status to breast cancer outcomes in tamoxifen-treated women; the majority of studies demonstrated that women with impaired CYP2D6 metabolism have lower endoxifen concentrations and a greater risk of breast cancer recurrence. As a result, practitioners must be aware that some of the most commonly prescribed medications coadministered with tamoxifen interfere with CYP2D6 function, thereby reducing endoxifen concentrations and potentially increasing the risk of breast cancer recurrence. After reviewing the published data regarding tamoxifen metabolism and the evidence relating CYP2D6 status to breast cancer outcomes in tamoxifen-treated patients, we are providing a guide for the use of medications that inhibit CYP2D6 in patients administered tamoxifen. PMID:20439629

  11. Impact of CYP2C19 polymorphism on the pharmacokinetics of nelfinavir in patients with pancreatic cancer

    PubMed Central

    Kattel, Krishna; Evande, Ruby; Tan, Chalet; Mondal, Goutam; Grem, Jean L; Mahato, Ram I

    2015-01-01

    Aim This study evaluated the influence of CYP2C19 polymorphisms on the pharmacokinetics of nelfinavir and its metabolite M8 in patients with pancreatic cancer. Methods Nelfinavir was administered orally to patients for over 10 days. The plasma concentrations of nelfinavir and M8 were measured by HPLC. The genotypes of CYP2C19*1, CYP2C19*2 and CYP2C19*3 were determined by the polymerase chain reaction-restriction fragment length polymorphism method. Results Pharmacokinetic profiles of nelfinavir and M8 were characterized by wide interindividual variability. The mean Cmax of nelfinavir in CYP2C19*1/*1 patients was 3.89 ± 0.40 (n = 3) and 5.12 ± 0.41 (n = 30) µg ml–1, while that of CYP2C19*1/*2 patients was 3.60 (n = 1) and 6.14 ± 0.31 (n = 5) µg ml–1 at the doses of 625 and 1250 mg nelfinavir twice daily, respectively. For the M8 metabolite, the mean Cmax of CYP2C19*1/*1 patients was 1.06 ± 0.06 (n = 3) and 1.58 ± 0.27 (n = 30) µg ml–1, while those of CYP2C19*1/*2 patients were 1.01 (n = 1) and 1.23 ± 0.15 (n = 5) µg ml–1 at the doses of 625 and 1250 mg nelfinavir twice daily, respectively. The area under the plasma concentration–time curve (AUC(0,12 h)) values of nelfinavir for CYP2C19*1/*1 patients were 28.90 ± 1.27 and 38.90 ± 4.99 µg ml–1·h and for CYP2C19*1/*2 patients, AUC(0,12 h) was 28.20 (n = 1) and 40.22 ± 3.17 (n = 5) µg ml–1·h at the doses of 625 and 1250 mg nelfinavir twice daily, respectively. The Cmax of nelfinavir was significantly higher (P <0.05) in CYP2C19*1/*2 patients but there was no statistical difference in AUC(0,12 h). Conclusion CYP2C19*1/*2 genotype modestly affected the pharmacokinetic profiles of nelfinavir and M8 in patients with locally advanced pancreatic cancer. PMID:25752914

  12. Detection of an endogenous urinary biomarker associated with CYP2D6 activity using global metabolomics

    PubMed Central

    Tay-Sontheimer, Jessica; Shireman, Laura M; Beyer, Richard P; Senn, Taurence; Witten, Daniela; Pearce, Robin E; Gaedigk, Andrea; Fomban, Cletus L Gana; Lutz, Justin D; Isoherranen, Nina; Thummel, Kenneth E; Fiehn, Oliver; Leeder, J Steven; Lin, Yvonne S

    2015-01-01

    Aim We sought to discover endogenous urinary biomarkers of human CYP2D6 activity. Patients & methods Healthy pediatric subjects (n = 189) were phenotyped using dextromethorphan and randomized for candidate biomarker selection and validation. Global urinary metabolomics was performed using liquid chromatography quadrupole time-of-flight mass spectrometry. Candidate biomarkers were tested in adults receiving fluoxetine, a CYP2D6 inhibitor. Results A biomarker, M1 (m/z 444.3102) was correlated with CYP2D6 activity in both the pediatric training and validation sets. Poor metabolizers had undetectable levels of M1, whereas it was present in subjects with other phenotypes. In adult subjects, a 9.56-fold decrease in M1 abundance was observed during CYP2D6 inhibition. Conclusion Identification and validation of M1 may provide a noninvasive means of CYP2D6 phenotyping. PMID:25521354

  13. 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. PMID:26400396

  14. 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

  15. The Effect of CYP2D6 Drug-Drug Interactions on Hydrocodone Effectiveness

    PubMed Central

    Monte, Andrew A.; Heard, Kennon J.; Campbell, Jenny; Hamamura, D.; Weinshilboum, Richard M.; Vasiliou, Vasilis

    2014-01-01

    Objectives The hepatic cytochrome 2D6 (CYP2D6) is a saturable enzyme responsible for metabolism of approximately 25% of known pharmaceuticals. CYP interactions can alter the efficacy of prescribed medications. Hydrocodone is largely dependent on CYP2D6 metabolism for analgesia, ondansetron is inactivated by CYP2D6, and oxycodone analgesia is largely independent of CYP2D6. The objective was to determine if CYP2D6 medication co-ingestion decreases the effectiveness of hydrocodone. Methods This was a prospective observational study conducted in an academic U.S. emergency department (ED). Subjects were included if they had self-reported pain or nausea; and were excluded if they were unable to speak English, were less than 18 years of age, had liver or renal failure, or carried diagnoses of chronic pain or cyclic vomiting. Detailed drug ingestion histories for the preceding 48 hours prior to the ED visit were obtained. The patient's pain and nausea were quantified using a 100-millimeter visual analogue scale (VAS) at baseline prior to drug administration and following doses of hydrocodone, oxycodone, or ondansetron. We used a mixed model with random subject effect to determine the interaction between CYP2D6 drug ingestion and study drug effectiveness. Odds ratios (OR) were calculated to compare clinically significant VAS changes between CYP2D6 users and non-users. Results Two hundred fifty (49.8%) of the 502 subjects enrolled had taken at least one CYP2D6 substrate, inhibitor, or inducing pharmaceutical, supplement, or illicit drug in the 48 hours prior to ED presentation. CYP2D6-drug users were one third as likely to respond to hydrocodone (OR 0.33, 95% CI = 0.1 to 0.8), and more than three times as likely as non-users to respond to ondansetron (OR 3.4, 95% CI = 1.3 to 9.1). There was no significant difference in oxycodone effectiveness between CYP2D6 users and non-users (OR 0.53, 95% CI = 0.3 to 1.1). Conclusions CYP2D6 drug-drug interactions appear to change

  16. Interindividual Variability of CYP2C19-Catalyzed Drug Metabolism Due to Differences in Gene Diplotypes and Cytochrome P450 Oxidoreductase Content

    PubMed Central

    Shirasaka, Yoshiyuki; Chaudhry, Amarjit S.; McDonald, Matthew; Prasad, Bhagwat; Wong, Timothy; Calamia, Justina C.; Fohner, Alie; Thornton, Timothy A.; Isoherranen, Nina; Unadkat, Jashvant D.; Rettie, Allan E.; Schuetz, Erin G.; Thummel, Kenneth E.

    2015-01-01

    Large interindividual variability has been observed in the metabolism of CYP2C19 substrates in vivo. The study aimed to evaluate sources of this variability in CYP2C19 activity, focusing on CYP2C19 diplotypes and the cytochrome P450 oxidoreductase (POR). CYP2C19 gene analysis was carried out on 347 human liver samples. CYP2C19 activity assayed using human liver microsomes (HLMs) confirmed a significant a priori predicted rank order for (S)-mephenytoin hydroxylase activity of CYP2C19*17/*17 > *1B/*17 > *1B/*1B > *2A/*17 > *1B/*2A > *2A/*2A diplotypes. In a multivariate analysis, the CYP2C19*2A allele and POR protein content were associated with CYP2C19 activity. Further analysis indicated a strong effect of the CYP2C19*2A, but not the *17, allele on both metabolic steps in the conversion of clopidogrel to its active metabolite. The present study demonstrates that interindividual variability in CYP2C19 activity is due to differences in both CYP2C19 protein content associated with gene diplotypes and the POR concentration. PMID:26323597

  17. Interindividual variability of CYP2C19-catalyzed drug metabolism due to differences in gene diplotypes and cytochrome P450 oxidoreductase content.

    PubMed

    Shirasaka, Y; Chaudhry, A S; McDonald, M; Prasad, B; Wong, T; Calamia, J C; Fohner, A; Thornton, T A; Isoherranen, N; Unadkat, J D; Rettie, A E; Schuetz, E G; Thummel, K E

    2016-08-01

    Large interindividual variability has been observed in the metabolism of CYP2C19 substrates in vivo. The study aimed to evaluate sources of this variability in CYP2C19 activity, focusing on CYP2C19 diplotypes and the cytochrome P450 oxidoreductase (POR). CYP2C19 gene analysis was carried out on 347 human liver samples. CYP2C19 activity assayed using human liver microsomes confirmed a significant a priori predicted rank order for (S)-mephenytoin hydroxylase activity of CYP2C19*17/*17 > *1B/*17 > *1B/*1B > *2A/*17 > *1B/*2A > *2A/*2A diplotypes. In a multivariate analysis, the CYP2C19*2A allele and POR protein content were associated with CYP2C19 activity. Further analysis indicated a strong effect of the CYP2C19*2A, but not the *17, allele on both metabolic steps in the conversion of clopidogrel to its active metabolite. The present study demonstrates that interindividual variability in CYP2C19 activity is due to differences in both CYP2C19 protein content associated with gene diplotypes and the POR concentration.The Pharmacogenomics Journal advance online publication, 1 September 2015; doi:10.1038/tpj.2015.58. PMID:26323597

  18. Concordance between CYP2D6 genotypes obtained from tumor-derived and germline DNA.

    PubMed

    Rae, James M; Regan, Meredith M; Thibert, Jacklyn N; Gersch, Christina; Thomas, Dafydd; Leyland-Jones, Brian; Viale, Giuseppe; Pusztai, Lajos; Hayes, Daniel F; Skaar, Todd; Van Poznak, Catherine

    2013-09-01

    Formalin-fixed, paraffin-embedded tumors (FFPETs) are a valuable source of DNA for genotype association studies and are often the only germline DNA resource from cancer clinical trials. The anti-estrogen tamoxifen is metabolized into endoxifen by CYP2D6, leading to the hypothesis that patients with certain CYP2D6 genotypes may not receive benefit because of their inability to activate the drug. Studies testing this hypothesis using FFPETs have provided conflicting results. It has been postulated that CYP2D6 genotype determined using FFPET may not be accurate because of somatic tumor alterations. In this study, we determined the concordance between CYP2D6 genotypes generated using 3 tissue sources (FFPETs; formalin-fixed, paraffin-embedded unaffected lymph nodes [FFPELNs]; and whole blood cells [WBCs]) from 122 breast cancer patients. Compared with WBCs, FFPET and FFPELN genotypes were highly concordant (>94%), as were the predicted CYP2D6 metabolic phenotypes (>97%). We conclude that CYP2D6 genotypes obtained from FFPETs accurately represent the patient's CYP2D6 metabolic phenotype. PMID:23958736

  19. Impact of CYP2D*6 in the adjuvant treatment of breast cancer patients with tamoxifen.

    PubMed

    Markopoulos, Christos; Kykalos, Stylianos; Mantas, Dimitrios

    2014-08-10

    Biotransformation of tamoxifen to the potent antiestrogen endoxifen is performed by cytochrome P450 (CYP) enzymes, in particular the CYP2D6 isoform. CYP2D6*4 is one of the most frequent alleles associated with loss of enzymatic activity. The incidence of CYP2D6*4 among Caucasians is estimated up to 27%, while it is present in up to 90% of all poor metabolizers within the Caucasian population. The hypothesis under question is whether the presence of one or two non-functioning (null) alleles predicts an inferior outcome in postmenopausal women with breast cancer receiving adjuvant treatment with tamoxifen. The numerous existing studies investigating the association of CYP2D6 with treatment failure in breast cancer are inconsistent and give rather conflicting results. Currently, routine CYP2D6 testing among women with breast cancer is not recommended and the significance of CYP2D6 phenotype in decision making regarding the administration of tamoxifen is unclear. The present study summarizes current literature regarding clinical studies on CYP2D6*4, particularly in terms of response to tamoxifen therapy and breast cancer outcome. PMID:25114852

  20. Impact of CYP2D*6 in the adjuvant treatment of breast cancer patients with tamoxifen

    PubMed Central

    Markopoulos, Christos; Kykalos, Stylianos; Mantas, Dimitrios

    2014-01-01

    Biotransformation of tamoxifen to the potent antiestrogen endoxifen is performed by cytochrome P450 (CYP) enzymes, in particular the CYP2D6 isoform. CYP2D6*4 is one of the most frequent alleles associated with loss of enzymatic activity. The incidence of CYP2D6*4 among Caucasians is estimated up to 27%, while it is present in up to 90% of all poor metabolizers within the Caucasian population. The hypothesis under question is whether the presence of one or two non-functioning (null) alleles predicts an inferior outcome in postmenopausal women with breast cancer receiving adjuvant treatment with tamoxifen. The numerous existing studies investigating the association of CYP2D6 with treatment failure in breast cancer are inconsistent and give rather conflicting results. Currently, routine CYP2D6 testing among women with breast cancer is not recommended and the significance of CYP2D6 phenotype in decision making regarding the administration of tamoxifen is unclear. The present study summarizes current literature regarding clinical studies on CYP2D6*4, particularly in terms of response to tamoxifen therapy and breast cancer outcome. PMID:25114852

  1. Regional and cellular expression of CYP2D6 in human brain: higher levels in alcoholics.

    PubMed

    Miksys, Sharon; Rao, Yushu; Hoffmann, Ewa; Mash, Deborah C; Tyndale, Rachel F

    2002-09-01

    Cytochrome P450 (CYP) 2D6 is expressed in liver, brain and other extrahepatic tissues where it metabolizes a range of centrally acting drugs and toxins. As ethanol can induce CYP2D in rat brain, we hypothesized that CYP2D6 expression is higher in brains of human alcoholics. We examined regional and cellular expression of CYP2D6 mRNA and protein by RT-PCR, Southern blotting, slot blotting, immunoblotting and immunocytochemistry. A significant correlation was found between mean mRNA and CYP2D6 protein levels across 13 brain regions. Higher expression was detected in 13 brain regions of alcoholics (n = 8) compared to nonalcoholics (n = 5) (anovap < 0.0001). In hippocampus this was localized in CA1-3 pyramidal cells and dentate gyrus granular neurons. In cerebellum this was localized in Purkinje cells and their dendrites. Both of these brain regions, and these same cell-types, are known to be susceptible to alcohol damage. For one case, a poor metabolizer (CYP2D6*4/*4), there was no detectable CYP2D6 protein, confirming the specificity of the antibody used. These data suggest that in alcoholics elevated brain CYP2D6 expression may contribute to altered sensitivity to centrally acting drugs and to the mediation of neurotoxic and behavioral effects of alcohol. PMID:12354285

  2. 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

  3. High Frequency of CYP2D6 Ultrarapid Metabolizer Genotype in the Finnish Population.

    PubMed

    Pietarinen, Paavo; Tornio, Aleksi; Niemi, Mikko

    2016-09-01

    CYP2D6 participates in the biotransformation of many commonly used drugs. Large genetic variability in CYP2D6 results in a wide interindividual variability in the response to CYP2D6 substrate drugs. Previous studies have assessed the phenotype and genotype distributions of CYP2D6 in relatively small Finnish population samples. The aim of our study was to investigate the frequencies of CYP2D6 genotypes in a larger Finnish population cohort of 857 healthy volunteers. The volunteers were genotyped for 10 CYP2D6 genetic variants (*2, *3, *4, *5, *6, *9, *10, *17, *39, *41) and copy number variation performed with TaqMan genotyping assays and copy number assay targeting exon 9. CYP2D6 phenotypes were inferred from the genotype data with the classical and activity score methods. According to the classical method, a large majority of the study cases were extensive metabolizers (EM; 87.3%; 95% confidence interval 84.9-89.3) and the second largest group was ultrarapid metabolizers (UM; 7.2%; 5.7-9.2%). Intermediate (IM) and poor metabolizers (PM) were in clear minority (3.0%; 2.1-4.4% and 2.3%; 1.5-3.6%, respectively). The activity score method yielded similar phenotype predictions. These results show that the frequency of UM genotype is higher and that of PM and IM genotype is lower in the Finnish population than in other North European populations. Accordingly, CYP2D6 genetic profile of the Finnish population differs from its geographically close neighbours, which has implications for the effective and safe use of drugs metabolized by CYP2D6. PMID:27038154

  4. 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

  5. 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

  6. CYP2E1 and Oxidative Liver Injury by Alcohol

    PubMed Central

    Lu, Yongke; Cederbaum, Arthur I.

    2008-01-01

    Ethanol-induced oxidative stress appears to play a major role in mechanisms by which ethanol causes liver injury. Many pathways have been suggested to contribute to the ability of ethanol to induce a state of oxidative stress. One central pathway appears to be the induction of cytochrome P450 2E1 (CYP2E1) by ethanol. CYP2E1 metabolizes and activates many toxicological substrates, including ethanol, to more reactive, toxic products. Levels of CYP2E1 are elevated under a variety of physiological and pathophysiological conditions, and after acute and chronic alcohol treatment. CYP2E1 is also an effective generator of reactive oxygen species such as the superoxide anion radical and hydrogen peroxide, and in the presence of iron catalysts, produces powerful oxidants such as the hydroxyl radical. This Review Article summarizes some of the biochemical and toxicological properties of CYP2E1, and briefly describes the use of cell lines developed to constitutively express CYP2E1 in assessing the actions of CYP2E1. Possible therapeutic implications for treatment of alcoholic liver injury by inhibition of CYP2E1 or CYP2E1-dependent oxidative stress will be discussed, followed by some future directions which may help to understand the actions of CYP2E1 and its role in alcoholic liver injury. PMID:18078827

  7. 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.

  8. 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

  9. Association of Cytochrome P450 2C19 Genotype With the Antiplatelet Effect and Clinical Efficacy of Clopidogrel Therapy

    PubMed Central

    Shuldiner, Alan R.; O'Connell, Jeffrey R.; Bliden, Kevin P.; Gandhi, Amish; Ryan, Kathleen; Horenstein, Richard B.; Damcott, Coleen M.; Pakyz, Ruth; Tantry, Udaya S.; Gibson, Quince; Pollin, Toni I.; Post, Wendy; Parsa, Afshin; Mitchell, Braxton D.; Faraday, Nauder; Herzog, William; Gurbel, Paul A.

    2013-01-01

    Context Clopidogrel therapy improves cardiovascular outcomes in patients with acute coronary syndromes and following percutaneous coronary intervention by inhibiting adenosine diphosphate (ADP)–dependent platelet activation. However, nonresponsiveness is widely recognized and is related to recurrent ischemic events. Objective To identify gene variants that influence clopidogrel response. Design, Setting, and Participants In the Pharmacogenomics of Antiplatelet Intervention (PAPI) Study (2006-2008), we administered clopidogrel for 7 days to 429 healthy Amish persons and measured response by ex vivo platelet aggregometry. A genome-wide association study was performed followed by genotyping the loss-of-function cytochrome P450 (CYP) 2C19*2 variant (rs4244285). Findings in the PAPI Study were extended by examining the relation of CYP2C19*2 genotype to platelet function and cardiovascular outcomes in an independent sample of 227 patients undergoing percutaneous coronary intervention. Main Outcome Measure ADP-stimulated platelet aggregation in response to clopidogrel treatment and cardiovascular events. Results Platelet response to clopidogrel was highly heritable (h2=0.73; P<.001). Thirteen single-nucleotide polymorphisms on chromosome 10q24 within the CYP2C18-CYP2C19-CYP2C9-CYP2C8 cluster were associated with diminished clopidogrel response, with a high degree of statistical significance (P=1.5 × 10−13 for rs12777823, additive model). The rs12777823 polymorphism was in strong linkage disequilibrium with the CYP2C19*2 variant, and was associated with diminished clopidogrel response, accounting for 12% of the variation in platelet aggregation to ADP (P=4.3 × 10−11). The relation between CYP2C19*2 genotype and platelet aggregation was replicated in clopidogrel-treated patients undergoing coronary intervention (P=.02). Furthermore, patients with the CYP2C19*2 variant were more likely (20.9% vs 10.0%) to have a cardiovascular ischemic event or death during 1 year of

  10. Influence of CYP2B6 and CYP2C19 polymorphisms on sertraline metabolism in major depression patients.

    PubMed

    Yuce-Artun, Nazan; Baskak, Bora; Ozel-Kizil, Erguvan Tugba; Ozdemir, Hatice; Uckun, Zuhal; Devrimci-Ozguven, Halise; Suzen, Halit Sinan

    2016-04-01

    Background Genetic polymorphisms in CYP2B6 and CYP2C19 may cause variability in the metabolism of sertraline, a widely used antidepressant in major depressive disorder treatment. Objective This study investigates the impact of CYP2B6*4 (785A > G), CYP2B6*9 (516G > T), CYP2B6*6 (516G > T + 685G > A) CYP2C19*2 (685G > A), CYP2C19*17 (-3402C > T) polymorphisms on plasma concentrations of sertraline and N-desmethyl sertraline in major depression patients treated with sertraline [n = 50]. Setting Participants were patients who admitted to an adult psychiatry outpatient unit at a university hospital. These were DSM-IV major depression diagnosed patients with a stable sertraline medication regimen [for at least one month]. Methods CYP2B6*4 (rs 2279343; 785A > G), CYP2B6*9 (516G > T; rs 3745274), CYP2B6*6 (516G > T + 685G > A) CYP2C19*2 (rs 4244285; 685G > A), CYP2C19*17 (rs 11188072; -3402C > T), polymorphisms were analyzed by polymerase chain reaction and restriction fragment length polymorphism. Plasma concentrations were measured by high-performance liquid chromatography in patients treated with SERT. Main outcome measure The distribution of CYP2B6*4, *6, *9 and CYP2C19*2, *17 among patient group and the association between genotype and sertraline metabolism. Results Sertraline, N-desmethyl sertraline, N-desmethyl sertraline/sertraline and dose-adjusted plasma concentrations were statistically compared between individuals with wild-type and variant alleles both for CYP2B6 and CYP2C19 enzymes. The mean N-desmethyl sertraline/sertraline value, was significantly lower in all subgroups with *6 and *9 variant alleles (p < 0.05). Sertraline/C values were significantly higher (p <  0.05) and N-desmethyl sertraline/C values were lower in all subgroups with *6 and *9 variant alleles compared to wild-type subgroup. Conclusion CYP2B6*6 and *9 variant alleles had a significant decreasing effect on sertraline metabolism in major depression

  11. The Psychostimulant Khat (Catha edulis) Inhibits CYP2D6 Enzyme Activity in Humans.

    PubMed

    Bedada, Worku; de Andrés, Fernando; Engidawork, Ephrem; Pohanka, Anton; Beck, Olof; Bertilsson, Leif; Llerena, Adrián; Aklillu, Eleni

    2015-12-01

    The use of khat (Catha edulis) while on medication may alter treatment outcome. In particular, the influence of khat on the metabolic activities of drug-metabolizing enzymes is not known. We performed a comparative 1-way crossover study to evaluate the effect of khat on cytochrome P450 (CYP)2D6 and CYP3A4 enzyme activity. After 1 week of khat abstinence, baseline CYP2D6 and CYP3A4 metabolic activities were determined in 40 Ethiopian male volunteers using 30 mg dextromethorphan (DM) as a probe drug and then repeated after 1 week of daily use of 400 g fresh khat leaves. Urinary concentrations of cathinone and cathine were determined to monitor the subjects' compliance to the study protocol. Genotyping for CYP2D6*3 and CYP2D6*4 was done. Plasma DM, dextrorphan and 3-methoxymorphinan concentrations were quantified. CYP2D6 and CYP3A4 enzyme activities were assessed by comparing plasma log DM/dextrorphan and log DM/methoxymorphinan metabolic ratio (MR) respectively in the presence and absence of khat. Cytochrome 2D6 MR was significantly increased from baseline by concurrent khat use (paired t test, P = 0.003; geometric mean ratio, 1.38; 95% confidence interval [95% CI], 1.12-1.53). Moreover, the inhibition of CYP2D6 activity by khat was more pronounced in CYP2D6*1/*1 compared with CYP2D6*1/*4 genotypes (P = 0.01). A marginal inhibition of CYP3A4 activity in the presence of khat was observed (P = 0.24). The mean percentage increase of CYP2D6 and CYP3A4 MR from baseline by khat use was 46% (95% CI, 20-72) and 31% (95% CI, 8-54), respectively. This is the first report linking khat use with significant inhibition of CYP2D6 metabolic activity in humans. PMID:26444948

  12. Haloperidol plasma concentration in Japanese psychiatric subjects with gene duplication of CYP2D6

    PubMed Central

    Ohnuma, Tohru; Shibata, Nobuto; Matsubara, Yoichiro; Arai, Heii

    2003-01-01

    Aims The cytochrome P-450 2D6 (CYP2D6) gene duplication/multiduplication producing an increase in enzyme activity, and the common Japanese mutation, CYP2D6*10A producing a decrease of enzyme activity were screened in a large number of Japanese psychiatric subjects (n = 111) in order to investigate whether these mutated alleles affected the plasma concentration of haloperidol. Methods Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was performed to identify the CYP2D6*10A and CYP2D6*2 genotypes in subjects who had been taking haloperidol. For the screening of duplicated active CYP2D6 gene, allele-specific long PCR was performed. Plasma concentration of haloperidol was measured by the enzyme immunoassay, and expressed as ‘plasma concentration dose ratio’ to normalize individual differences. Results The plasma concentration–dose ratio showed large interindividual differences of approximately 18-fold. PCR-RFLP methods revealed that 29 (26.1%), 10 (9.0%), 39 (35.1%), 0 (0%), seven (6.3%) and 26 (23.4%) cases possessed the CYP2D6 genotypes *1/*1, *1/*2, *1/*10A, *2/*2, *2/*10A and *10 A/*10A, respectively. Six cases (5.4%) had duplicated CYP2D6 genes. There were no significant differences of plasma concentration–dose ratio between the groups classified by CYP2D6*10A and *2 genotypes (Kruskal–Wallis test; P = 0.37), even in those cases whose daily doses were lower than 20 mg (n = 90, P = 0.91). Subjects having duplicated genes (n = 6) did not show significant differences of plasma concentration–dose ratio by comparison with subjects who had no duplicated genes (Mann–Whitney U-test; P = 0.80). Conclusions Gene duplication, and the common Japanese mutation CYP2D6*10A on CYP2D6 gene are not likely to be the main modulatory factors of plasma concentration of haloperidol in Japanese psychiatric subjects. PMID:12919180

  13. Establishment of CYP2D6 reference samples by multiple validated genotyping platforms.

    PubMed

    Fang, H; Liu, X; Ramírez, J; Choudhury, N; Kubo, M; Im, H K; Konkashbaev, A; Cox, N J; Ratain, M J; Nakamura, Y; O'Donnell, P H

    2014-12-01

    Cytochrome P450 2D6 (cytochrome P450, family 2, subfamily D, polypeptide 6 (CYP2D6)), a highly polymorphic drug-metabolizing enzyme, is involved in the metabolism of one-quarter of the most commonly prescribed medications. Here we have applied multiple genotyping methods and Sanger sequencing to assign precise and reproducible CYP2D6 genotypes, including copy numbers, for 48 HapMap samples. Furthermore, by analyzing a set of 50 human liver microsomes using endoxifen formation from N-desmethyl-tamoxifen as the phenotype of interest, we observed a significant positive correlation between CYP2D6 genotype-assigned activity score and endoxifen formation rate (rs = 0.68 by rank correlation test, P = 5.3 × 10(-8)), which corroborated the genotype-phenotype prediction derived from our genotyping methodologies. In the future, these 48 publicly available HapMap samples characterized by multiple substantiated CYP2D6 genotyping platforms could serve as a reference resource for assay development, validation, quality control and proficiency testing for other CYP2D6 genotyping projects and for programs pursuing clinical pharmacogenomic testing implementation. PMID:24980783

  14. Establishment of CYP2D6 Reference Samples by Multiple Validated Genotyping Platforms

    PubMed Central

    Fang, Hua; Liu, Xiao; Ramírez, Jacqueline; Choudhury, Noura; Kubo, Michiaki; Im, Hae Kyung; Konkashbaev, Anuar; Cox, Nancy J.; Ratain, Mark J.; Nakamura, Yusuke; O’Donnell, Peter H.

    2014-01-01

    Cytochrome P450 2D6 (cytochrome P450, family 2, subfamily D, polypeptide 6, or CYP2D6), a highly polymorphic drug metabolizing enzyme, is involved in the metabolism of one quarter of the most commonly prescribed medications. Here, we have applied multiple genotyping methods and Sanger sequencing to assign precise and reproducible CYP2D6 genotypes, including copy numbers, for 48 HapMap samples. Furthermore, by analyzing a set of 50 human liver microsomes using endoxifen formation from N-desmethyl-tamoxifen as the phenotype of interest, we observed a significant positive correlation between CYP2D6 genotype-assigned activity score and endoxifen formation rate (rs = 0.68 by Rank correlation test, P = 5.3 ×10−8), which corroborated the genotype-phenotype prediction derived from our genotyping methodologies. In the future, these 48 publicly available HapMap samples characterized by multiple substantiated CYP2D6 genotyping platforms could serve as a reference resource for assay development, validation, quality control, and proficiency testing for other CYP2D6 genotyping projects, and for programs pursuing clinical pharmacogenomic testing implementation. PMID:24980783

  15. Genetic polymorphisms of CYP2D6 oxidation in patients with autoimmune bullous diseases

    PubMed Central

    Rychlik-Sych, Mariola; Baranska, Małgorzata; Waszczykowska, Elzbieta; Torzecka, Jolanta Dorota; Skretkowicz, Jadwiga

    2013-01-01

    Introduction Bullous skin diseases, which include, among others pemphigoid, pemphigus, and dermatitis herpetiformis are classified as severe autoimmune dermatoses. It has been shown that a pattern of xenobiotic metabolism may play a role in the pathogenesis of autoimmune diseases. Aim To estimate whether the CYP2D6 genotype may be considered a predisposing factor in autoimmune bullous diseases induction. Material and methods The study included 72 patients with autoimmune bullous diseases: 37 with pemphigoid, 21 with pemphigus, and 14 with dermatitis herpetiformis (DH). The CYP2D6 genotypes were analyzed by the polymerase chain reaction fragment length polymorphism (PCR-RFLP) method. Results Relative risk of DH development for particular genotype carriers expressed by odds ratio (OR) was statistically significantly higher for subjects with CYP2D6*1/CYP2D6*4 (OR = 4.2; p = 0.0104) and 2-fold higher for subjects with CYP2D6*4 (OR = 2.3; p = 0.0351). Conclusions The results of the present study show that the CYP2D6 oxidation polymorphism cannot be considered a risk factor for development of pemphigoid and pemphigus, however it might have an impact on dermatitis herpetiformis. PMID:24278077

  16. Polymorphism of human cytochrome P450 2D6 and its clinical significance: part II.

    PubMed

    Zhou, Shu-Feng

    2009-01-01

    Part I of this article discussed the potential functional importance of genetic mutations and alleles of the human cytochrome P450 2D6 (CYP2D6) gene. The impact of CYP2D6 polymorphisms on the clearance of and response to a series of cardiovascular drugs was addressed. Since CYP2D6 plays a major role in the metabolism of a large number of other drugs, Part II of the article highlights the impact of CYP2D6 polymorphisms on the response to other groups of clinically used drugs. Although clinical studies have observed a gene-dose effect for some tricyclic antidepressants, it is difficult to establish clear relationships of their pharmacokinetics and pharmacodynamic parameters to genetic variations of CYP2D6; therefore, dosage adjustment based on the CYP2D6 phenotype cannot be recommended at present. There is initial evidence for a gene-dose effect on commonly used selective serotonin reuptake inhibitors (SSRIs), but data on the effect of the CYP2D6 genotype/phenotype on the response to SSRIs and their adverse effects are scanty. Therefore, recommendations for dose adjustment of prescribed SSRIs based on the CYP2D6 genotype/phenotype may be premature. A number of clinical studies have indicated that there are significant relationships between the CYP2D6 genotype and steady-state concentrations of perphenazine, zuclopenthixol, risperidone and haloperidol. However, findings on the relationships between the CYP2D6 genotype and parkinsonism or tardive dyskinesia treatment with traditional antipsychotics are conflicting, probably because of small sample size, inclusion of antipsychotics with variable CYP2D6 metabolism, and co-medication. CYP2D6 phenotyping and genotyping appear to be useful in predicting steady-state concentrations of some classical antipsychotic drugs, but their usefulness in predicting clinical effects must be explored. Therapeutic drug monitoring has been strongly recommended for many antipsychotics, including haloperidol, chlorpromazine, fluphenazine

  17. CYP2D6 genotype and adjuvant tamoxifen: meta-analysis of heterogeneous study populations.

    PubMed

    Province, M A; Goetz, M P; Brauch, H; Flockhart, D A; Hebert, J M; Whaley, R; Suman, V J; Schroth, W; Winter, S; Zembutsu, H; Mushiroda, T; Newman, W G; Lee, M-T M; Ambrosone, C B; Beckmann, M W; Choi, J-Y; Dieudonné, A-S; Fasching, P A; Ferraldeschi, R; Gong, L; Haschke-Becher, E; Howell, A; Jordan, L B; Hamann, U; Kiyotani, K; Krippl, P; Lambrechts, D; Latif, A; Langsenlehner, U; Lorizio, W; Neven, P; Nguyen, A T; Park, B-W; Purdie, C A; Quinlan, P; Renner, W; Schmidt, M; Schwab, M; Shin, J-G; Stingl, J C; Wegman, P; Wingren, S; Wu, A H B; Ziv, E; Zirpoli, G; Thompson, A M; Jordan, V C; Nakamura, Y; Altman, R B; Ames, M M; Weinshilboum, R M; Eichelbaum, M; Ingle, J N; Klein, T E

    2014-02-01

    The International Tamoxifen Pharmacogenomics Consortium was established to address the controversy regarding cytochrome P450 2D6 (CYP2D6) status and clinical outcomes in tamoxifen therapy. We performed a meta-analysis on data from 4,973 tamoxifen-treated patients (12 globally distributed sites). Using strict eligibility requirements (postmenopausal women with estrogen receptor-positive breast cancer, receiving 20 mg/day tamoxifen for 5 years, criterion 1); CYP2D6 poor metabolizer status was associated with poorer invasive disease-free survival (IDFS: hazard ratio = 1.25; 95% confidence interval = 1.06, 1.47; P = 0.009). However, CYP2D6 status was not statistically significant when tamoxifen duration, menopausal status, and annual follow-up were not specified (criterion 2, n = 2,443; P = 0.25) or when no exclusions were applied (criterion 3, n = 4,935; P = 0.38). Although CYP2D6 is a strong predictor of IDFS using strict inclusion criteria, because the results are not robust to inclusion criteria (these were not defined a priori), prospective studies are necessary to fully establish the value of CYP2D6 genotyping in tamoxifen therapy. PMID:24060820

  18. 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

  19. Expansion of a PBPK model to predict disposition in pregnant women of drugs cleared via multiple CYP enzymes, including CYP2B6, CYP2C9 and CYP2C19

    PubMed Central

    Ke, Alice Ban; Nallani, Srikanth C; Zhao, Ping; Rostami-Hodjegan, Amin; Unadkat, Jashvant D

    2014-01-01

    Aim Conducting PK studies in pregnant women is challenging. Therefore, we asked if a physiologically-based pharmacokinetic (PBPK) model could be used to predict the disposition in pregnant women of drugs cleared by multiple CYP enzymes. Methods We expanded and verified our previously published pregnancy PBPK model by incorporating hepatic CYP2B6 induction (based on in vitro data), CYP2C9 induction (based on phenytoin PK) and CYP2C19 suppression (based on proguanil PK), into the model. This model accounted for gestational age-dependent changes in maternal physiology and hepatic CYP3A, CYP1A2 and CYP2D6 activity. For verification, the pregnancy-related changes in the disposition of methadone (cleared by CYP2B6, 3A and 2C19) and glyburide (cleared by CYP3A, 2C9 and 2C19) were predicted. Results Predicted mean post-partum to second trimester (PP : T2) ratios of methadone AUC, Cmax and Cmin were 1.9, 1.7 and 2.0, vs. observed values 2.0, 2.0 and 2.6, respectively. Predicted mean post-partum to third trimester (PP : T3) ratios of methadone AUC, Cmax and Cmin were 2.1, 2.0 and 2.4, vs. observed values 1.7, 1.7 and 1.8, respectively. Predicted PP : T3 ratios of glyburide AUC, Cmax and Cmin were 2.6, 2.2 and 7.0 vs. observed values 2.1, 2.2 and 3.2, respectively. Conclusions Our PBPK model integrating prior physiological knowledge, in vitro and in vivo data, allowed successful prediction of methadone and glyburide disposition during pregnancy. We propose this expanded PBPK model can be used to evaluate different dosing scenarios, during pregnancy, of drugs cleared by single or multiple CYP enzymes. PMID:23834474

  20. The nuclear receptor NR2E1/TLX controls senescence

    PubMed Central

    Krusche, Benjamin; Pemberton, Helen; Alonso, Marta M.; Chandler, Hollie; Brookes, Sharon; Parrinello, Simona; Peters, Gordon; Gil, Jesús

    2014-01-01

    The nuclear receptor NR2E1 (also known as TLX or tailless) controls the self-renewal of neural stem cells (NSCs) and has been implied as an oncogene which initiates brain tumours including glioblastomas. Despite NR2E1 regulating targets like p21CIP1 or PTEN we still lack a full explanation for its role in NSC self-renewal and tumorigenesis. We know that Polycomb repressive complexes (PRC) also control stem cell self-renewal and tumorigenesis, but so far, no formal connection has been established between NR2E1 and PRCs. In a screen for transcription factors regulating the expression of the Polycomb protein CBX7, we identified NR2E1 as one of its more prominent regulators. NR2E1 binds at the CBX7 promoter, inducing its expression. Notably CBX7 represses NR2E1 as part of a regulatory loop. Ectopic NR2E1 expression inhibits cellular senescence, extending cellular lifespan in fibroblasts via CBX7-mediated regulation of p16INK4a and direct repression of p21CIP1. In addition NR2E1 expression also counteracts oncogene-induced senescence (OIS). The importance of NR2E1 to restrain senescence is highlighted through the process of knocking down its expression, which causes premature senescence in human fibroblasts and epithelial cells. We also confirmed that NR2E1 regulates CBX7 and restrains senescence in NSCs. Finally, we observed that the expression of NR2E1 directly correlates with that of CBX7 in human glioblastoma multiforme. Overall we identified control of senescence and regulation of Polycomb action as two possible mechanisms that can join those so far invoked to explain the role of NR2E1 in control of NSC self-renewal and cancer. PMID:25328137

  1. Chemical characteristics for optimizing CYP2E1 inhibition.

    PubMed

    van de Wier, B; Balk, J M; Bast, A; Koek, G H; Haenen, G R M M

    2015-12-01

    Cytochrome P450 2E1 (CYP2E1) expression and activity in the liver is associated with the degree of liver damage in patients with alcoholic steatohepatitis (ASH) as well as non-alcoholic steatohepatitis (NASH). CYP2E1 is known to generate reactive oxygen species, which leads to oxidative stress, one of the hallmarks of both diseases. Apart from ROS, toxic metabolites can be formed by CYP2E1 metabolism, further potentiating liver injury. Therefore, CYP2E1 is implicated in the pathogenesis of ASH and NASH. The aim of this study was to determine the chemical characteristics of compounds that are important to inhibit CYP2E1. To this end, structurally related analogs that differed in their lipophilic, steric and electronic properties were tested. In addition, homologues series of aliphatic primary alcohols, secondary alcohols, aldehydes, ketones and carboxylic acids were tested. It was found that inhibition of the CYP2E1 activity is primarily governed by lipophilicity. The optimal log D7.4 (octanol/water distribution coefficient at pH 7.4) value for inhibition of CYP2E1 was approximately 2.4. In the carboxylic acids series the interaction of the carboxylate group with polar residues lining the CYP2E1 active site also has to be considered. This study sketches the basic prerequisites in the search for inhibitors of CYP2E1, which would strengthen our therapeutic armamentarium against CYP2E1 associated diseases, such as ASH and NASH. PMID:26428356

  2. 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

  3. 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.

  4. Clinical Pharmacogenetics Implementation Consortium guidelines for cytochrome P450 2D6 genotype and codeine therapy: 2014 update.

    PubMed

    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

    2014-04-01

    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

  5. Stereoselective hydroxylation by CYP2C19 and oxidation by ADH4 in the in vitro metabolism of tivantinib.

    PubMed

    Nishiya, Yumi; Nakai, Daisuke; Urasaki, Yoko; Takakusa, Hideo; Ohsuki, Satoru; Iwano, Yuji; Yasukochi, Takanori; Takayama, Tomoko; Bazyo, Shohei; Oza, Chikahiro; Kurihara, Atsushi; Savage, Ronald E; Izumi, Takashi

    2016-11-01

    1. In prior studies, it has been shown that tivantinib is extensively metabolized in humans to many oxidative metabolites and glucuronides. In order to identify the responsible enzymes, we investigated the in vitro metabolism of tivantinib and its four major circulating metabolites. 2. The primary isoforms involved in the elimination of tivantinib were CYP2C19 and CYP3A4/5. CYP2C19 showed catalytic activity for the formation of M5 (hydroxylated metabolite), but not for M4 (a stereoisomer of M5), whereas CYP3A4/5 catalyzed the formation of both metabolites. For the elimination of M4, M5 and M8 (keto-metabolite), CYP3A4/5 was the major cytochrome P450 isoform and UGT1A9 was mainly involved in the glucuronidation of M4 and M5. 3. ADH4 was identified as one of the major alcohol dehydrogenase isoforms contributing to the formation of M6 (sequential keto-metabolite of M4 and M5) and M8. The substrate preference of ADH for M4, and not M5, was observed in the formation of M6. 4. In conclusion, CYP2C19, CYP3A4/5, UGT1A9 and ADH4 were the primary drug metabolizing enzymes involved in the in vitro metabolism of tivantinib and its metabolites. The stereoselective hydroxylation by CYP2C19 and substrate stereoselectivity of ADH4-catalyzed oxidation in the in vitro metabolism of tivantinib was discovered. PMID:26899628

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

    PubMed

    Imamura, Chiyo K; Furihata, Kenichi; Okamoto, Shinichiro; Tanigawara, Yusuke

    2016-04-01

    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

  7. 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

  8. Association of CYP2C19 Polymorphisms with the Clinical Efficacy of Clopidogrel Therapy in Patients Undergoing Carotid Artery Stenting in Asia

    PubMed Central

    Zhu, Wen-Yao; Zhao, Ting; Xiong, Xiao-Yi; Li, Jie; Wang, Li; Zhou, Yu; Gong, Zi-Li; Cheng, Sai-Yu; Liu, Yong; Shuai, Jie; Yang, Qing-Wu

    2016-01-01

    The CYP2C19 gene plays a detrimental role in the metabolism of clopidogrel. This study aimed to investigate the association between CYP2C19 polymorphisms and the clinical efficacy of clopidogrel therapy in patients who have undergone carotid artery stenting (CAS). CYP2C19 genotype screening was performed on 959 ischemic stroke patients. Of these patients, 241 who had undergone CAS were enrolled in the study. They were all followed up for 1 year after stent surgery, and the primary clinical end-points were ischemic events. The frequencies of the CYP2C19*2 and *3 alleles among the 959 patients were 31.80% and 5.06%, respectively. Regarding the 241 participants who had undergone CAS, multivariate Cox regression analysis showed that the CYP2C19 loss-of-function (LOF) alleles (*2 and *3) were risk factors for post-CAS prognosis. Within 1 year of follow-up, the patients carrying the CYP2C19 LOF alleles were more likely to experience ischemic events than those carrying none. The occurrence of ischemic events did not significantly differ between the *2 and *3 allele carriers. Our results suggest that CYP2C19 LOF alleles (*2 and *3) significantly impact the prognosis of patients on clopidogrel therapy after CAS and that the CYP2C19*2 and CYP2C19*3 alleles have the same effects on prognosis. PMID:27137706

  9. CYP2D6 Genotype Dependent Oxycodone Metabolism in Postoperative Patients

    PubMed Central

    Stamer, Ulrike M.; Zhang, Lan; Book, Malte; Lehmann, Lutz E.; Stuber, Frank; Musshoff, Frank

    2013-01-01

    Background The impact of polymorphic cytochrome P450 CYP2D6 enzyme on oxycodone's metabolism and clinical efficacy is currently being discussed. However, there are only spare data from postoperative settings. The hypothesis of this study is that genotype dependent CYP2D6 activity influences plasma concentrations of oxycodone and its metabolites and impacts analgesic consumption. Methods Patients received oxycodone 0.05 mg/kg before emerging from anesthesia and patient-controlled analgesia (PCA) for the subsequent 48 postoperative hours. Blood samples were drawn at 30, 90 and 180 minutes after the initial oxycodone dose. Plasma concentrations of oxycodone and its metabolites oxymorphone, noroxycodone and noroxymorphone were analyzed by liquid chromatography-mass spectrometry with electrospray ionization. CYP2D6 genotyping was performed and 121 patients were allocated to the following genotype groups: PM (poor metabolizer: no functionally active CYP2D6 allele), HZ/IM (heterozygous subjects, intermediate metabolizers with decreased CYP2D6 activity), EM (extensive metabolizers, normal CYP2D6 activity) and UM (ultrarapid metabolizers, increased CYP2D6 activity). Primary endpoint was the genotype dependent metabolite ratio of plasma concentrations oxymorphone/oxycodone. Secondary endpoint was the genotype dependent analgesic consumption with calculation of equianalgesic doses compared to the standard non-CYP dependent opioid piritramide. Results Metabolism differed between CYP2D6 genotypes. Mean (95%-CI) oxymophone/oxycodone ratios were 0.10 (0.02/0.19), 0.13 (0.11/0.16), 0.18 (0.16/0.20) and 0.28 (0.07/0.49) in PM, HZ/IM, EM and UM, respectively (p = 0.005). Oxycodone consumption up to the 12th hour was highest in PM (p = 0.005), resulting in lowest equianalgesic doses of piritramide versus oxycodone for PM (1.6 (1.4/1.8); EM and UM 2.2 (2.1/2.3); p<0.001). Pain scores did not differ between genotypes. Conclusions In this postoperative setting, the number of

  10. Cytochrome P450 CYP2D6 gene polymorphism and lung cancer susceptibility in Caucasians.

    PubMed

    Legrand-Andréoletti, M; Stücker, I; Marez, D; Galais, P; Cosme, J; Sabbagh, N; Spire, C; Cenée, S; Lafitte, J J; Beaune, P; Broly, F

    1998-02-01

    Many studies have been performed in an attempt to establish a link between the polymorphism of the cytochrome P450 CYP2D6 gene and the incidence of lung cancer. Nevertheless, whether or not this genetic polymorphism has a role in the development of the disease remains unclear. Recently, new advances in our knowledge of the CYP2D6 gene and its locus (CYP2D) have been achieved. In particular, CYP2D6 was found to be highly polymorphic and multiple novel mutations and allelic variants of the gene have been identified. In addition, a number of CYP2D rearrangements, including those with amplification of the gene, have been demonstrated. Taking this new information into account, we have reconsidered the potential influence of CYP2D6 polymorphism in lung cancer susceptibility by performing a comparative analysis of the overall mutational spectrum of CYP2D6 and of the rearrangements of CYP2D in 249 patients with lung cancer and in 265 control individuals matched on age, sex, hospital and residence area. For this purpose, a strategy based on SSCP analysis of the entire coding sequence of CYP2D6 and on RFLP analysis of the gene locus was carried out in DNA samples from each individual. Forty mutations occurring in various combinations on 42 alleles of the gene and 82 different genotypes were identified. No significant difference in the distribution of the mutations, alleles or genotypes was observed between the two groups, except a particular genotype (CYP2D6*1A/*2), which was more common in the sub-group of moderate smokers (< 30 pack-years) suffering from small cell carcinoma (Odds Ratio (OR) 3.6, 95% CI 1.1-11.9). When the phenotype was predicted according to genotype, only a trend toward a higher frequency of ultrarapid metabolizers in patients was obtained. In spite of a complete analysis of the CYP2D6 gene and its locus, this case-control study provides elements against an influence of the CYP2D6 polymorphism on lung cancer susceptibility. PMID:9511176

  11. Understanding CYP2D6 and its role in tamoxifen metabolism.

    PubMed

    Smith, Edith Caroline

    2013-11-01

    The gene CYP2D6 has an extremely important role in drug metabolism. "Cytochrome P450, family 2, subfamily D, polypeptide 6" is the official name of CYP2D6. The gene is located at position 13.1 on the long (q) arm of chromosome 21 and encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases that are heavily involved in drug metabolism (Genetics Home Reference, 2013), and many drugs are activated into their biologically active compounds. Because of numerous polymorphisms, the gene also has significant person-to-person variability. To date, more than 80 distinct CYP2D6 alleles and specific types and frequencies have been associated with different ethnic groups. CYP2D6*4 is the most common variant allele in Caucasians and, in that population, has a frequency of about 25%. On the other hand, CYP2D6*10 is common in the Asian population (Stearns & Rae, 2008). PMID:24161632

  12. 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

  13. Clinical Relevance of CYP2D6 Genetics for Tamoxifen Response in Breast Cancer

    PubMed Central

    Brauch, Hiltrud; Schroth, Werner; Eichelbaum, Michel; Schwab, Matthias; Harbeck, Nadia

    2008-01-01

    Summary Tamoxifen is a standard endocrine therapy for the prevention and treatment of steroid hormone receptor-positive breast cancer. Tamoxifen requires enzymatic activation by CYP 450 enzymes for the formation of clinically relevant metabolites, 4-OH-tamoxifen and endoxifen, which both have a greater affinity to the estrogen receptor and ability to inhibit cell proliferation when compared to the parent drug. CYP2D6 is the key enzyme in this biotransformation, and recent mechanistic, pharmacologic, and clinical pharmacogenetic evidence suggests that genetic variants and drug interaction by CYP2D6 inhibitors influence plasma concentrations of active tamoxifen metabolites and outcome of patients treated with adjuvant tamoxifen. Particularly, non-functional (poor metabolizer) and severely impaired (intermediate metabolizer) CYP2D6 variants are associated with higher recurrence rates. Accordingly, CYP2D6 genotyping prior to treatment for prediction of metabolizer status and outcome may open new avenues for the individualization of endocrine treatment choice and benefit. Moreover, strong CYP2D6 inhibitors such as the selective serotonin reuptake inhibitor paroxetine should be avoided as co-medication. PMID:20824020

  14. Contributions of Ionic Interactions and Protein Dynamics to Cytochrome P450 2D6 (CYP2D6) Substrate and Inhibitor Binding*

    PubMed Central

    Wang, An; Stout, C. David; Zhang, Qinghai; Johnson, Eric F.

    2015-01-01

    P450 2D6 contributes significantly to the metabolism of >15% of the 200 most marketed drugs. Open and closed crystal structures of P450 2D6 thioridazine complexes were obtained using different crystallization conditions. The protonated piperidine moiety of thioridazine forms a charge-stabilized hydrogen bond with Asp-301 in the active sites of both complexes. The more open conformation exhibits a second molecule of thioridazine bound in an expanded substrate access channel antechamber with its piperidine moiety forming a charge-stabilized hydrogen bond with Glu-222. Incubation of the crystalline open thioridazine complex with alternative ligands, prinomastat, quinidine, quinine, or ajmalicine, displaced both thioridazines. Quinine and ajmalicine formed charge-stabilized hydrogen bonds with Glu-216, whereas the protonated nitrogen of quinidine is equidistant from Asp-301 and Glu-216 with protonated nitrogen H-bonded to a water molecule in the access channel. Prinomastat is not ionized. Adaptations of active site side-chain rotamers and polypeptide conformations were evident between the complexes, with the binding of ajmalicine eliciting a closure of the open structure reflecting in part the inward movement of Glu-216 to form a hydrogen bond with ajmalicine as well as sparse lattice restraints that would hinder adaptations. These results indicate that P450 2D6 exhibits sufficient elasticity within the crystal lattice to allow the passage of compounds between the active site and bulk solvent and to adopt a more closed form that adapts for binding alternative ligands with different degrees of closure. These crystals provide a means to characterize substrate and inhibitor binding to the enzyme after replacement of thioridazine with alternative compounds. PMID:25555909

  15. Individualization of tamoxifen therapy: much more than just CYP2D6 genotyping.

    PubMed

    Binkhorst, Lisette; Mathijssen, Ron H J; Jager, Agnes; van Gelder, Teun

    2015-03-01

    Clinical response to tamoxifen varies widely among women treated with this drug for hormone receptor-positive breast cancer. The principal active metabolite - endoxifen - is generated through hepatic metabolism of tamoxifen, with key roles for cytochrome P450 (CYP) CYP2D6 and CYP3A. By influencing endoxifen formation, genetic variants of CYP2D6 may affect response to tamoxifen. After a decade of research, examining the effects of CYP2D6 genetic variants on tamoxifen efficacy, there is still no agreement on the clinical utility of CYP2D6 genotype as biomarker for the prediction of breast cancer outcome, because studies revealed conflicting results. However, tamoxifen metabolism is complex and involves several other drug-metabolizing enzymes. Genetic variants of other CYP enzymes, including CYP3A4 and CYP2C9/19, as well as co-medication interfering with the metabolic activity of CYP2D6 and CYP3A4 have been shown to affect endoxifen concentrations and may also contribute to the variability in response to tamoxifen. Phenotyping strategies can predict endoxifen exposure more accurately than CYP2D6 genotype, but do not take into account all factors influencing endoxifen exposure. Therapeutic drug monitoring (TDM) is likely to be the optimal strategy for individualization of tamoxifen treatment. According to a growing amount of literature, endoxifen concentration seems to be a predictor of clinical outcome. The relationship between endoxifen levels and breast cancer outcomes has to be replicated and confirmed and the value of TDM should be evaluated in prospective clinical trials. Caution is advised regarding the concomitant use of medications which could interact with tamoxifen, including inhibitors and inducers of CYP enzymes. PMID:25618289

  16. Interpreting the CYP2D6 Results From the International Tamoxifen Pharmacogenetics Consortium

    PubMed Central

    Province, MA; Altman, RB; Klein, TE

    2014-01-01

    Meta-analysis of the entire analyzable cohort of 4,935 tamoxifen-treated breast cancer patients by the International Tamoxifen Pharmacogenetics Consortium (ITPC) (criterion 3) revealed no CYP2D6 effect on outcomes but strong heterogeneity across sites.1 However, a post hoc–defined subgroup (criterion 1: postmenopausal, estrogen receptor positive, receiving 20 mg/day tamoxifen for 5 years; n = 1,996) did find statistically significant effect of CYP2D6 on both invasive disease–free survival as well as breast cancer–free interval, with little site heterogeneity. How should we interpret these discrepant findings? PMID:25056393

  17. 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. PMID:25926433

  18. CYP2D6 phenotype-genotype relationships in African-Americans and Caucasians in Los Angeles.

    PubMed

    Leathart, J B; London, S J; Steward, A; Adams, J D; Idle, J R; Daly, A K

    1998-12-01

    CYP2D6 genotyping (CYP2D6*3, CYP2D6*4, CYP2D6*5, CYP2D6*13, CYP2D6*16 alleles and gene duplications) was previously performed on 1053 Caucasian and African-American lung cancer cases and control individuals and no significant difference in allele frequencies between cases and control individuals detected. We have carried out additional genotyping (CYP2D6*6, CYP2D6*7, CYP2D6*8, CYP2D6*9, CYP2D6*10, CYP2D6*17 alleles) and debrisoquine phenotyping on subgroups from this study to assess phenotype-genotype relationships. African-Americans showed significant differences from Caucasians with respect to frequency of defective CYP2D6 alleles, particularly CYP2D6*4 and CYP2D6*5. The CYP2D6*17 allele occurred at a frequency of 0.26 among 87 African-Americans and appeared to explain higher average metabolic ratios among African-Americans compared with Caucasians. CYP2D6*6, CYP2D6*8, CYP2D6*9 and CYP2D6*10 were rare in both ethnic groups but explained approximately 40% of higher than expected metabolic ratios among extensive metabolizers. Among individuals phenotyped with debrisoquine, 32 out of 359 were in the poor metabolizer range with 24 of these (75%) also showing two defective CYP2D6 alleles. Additional single strand conformational polymorphism analysis screening of samples showing large phenotype-genotype discrepancies resulted in the detection of three novel polymorphisms. If subjects taking potentially interfering drugs were excluded, this additional screening enabled the positive identification of 88% of phenotypic poor metabolizers by genotyping. This sensitivity was comparable with that of phenotyping, which identified 90% of those with two defective alleles as poor metabolizers. PMID:9918137

  19. Pharmacogenetics of CYP2D6 and tamoxifen therapy: Light at the end of the tunnel?

    PubMed

    Del Re, M; Citi, V; Crucitta, S; Rofi, E; Belcari, F; van Schaik, R H; Danesi, R

    2016-05-01

    The clinical usefulness of assessing the enzymatic activity of CYPD6 in patients taking tamoxifen had been longly debated. In favour of preemptive evaluation of phenotypic profile of patients is the strong pharmacologic rationale, being that the formation of endoxifen, the major and clinically most important metabolite of tamoxifen, is largely dependent on the activity of CYP2D6. This enzyme is highly polymorphic for which the activity is largely depending on genetics, but that can also be inhibited by a number of drugs, i.e. antidepressants, which are frequently used in patients with cancer. Unfortunately, the clinical trials that have been published in the last years are contradicting each other on the association between CYP2D6 and significant clinical endpoints, and for this reason CYP2D6 genotyping is at present not generally recommended. Despite this, the CYP2D6 genotyping test for tamoxifen is available in many laboratories and it may still be an appropriate test to use it in specific cases. PMID:27060675

  20. 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

  1. Impact of CYP2D6 polymorphisms in tamoxifen adjuvant breast cancer treatment.

    PubMed

    Ramón y Cajal, T; Altés, A; Paré, L; del Rio, E; Alonso, C; Barnadas, A; Baiget, M

    2010-01-01

    The aim of this study is to evaluate the impact of CYP2D6 genotyping in predicting disease-free survival and toxicity in breast cancer patients treated with adjuvant tamoxifen. DNA from 91 patients was genotyped using the AmpliChip CYP450 GeneChip, Roche that facilitates the classification of individuals by testing 27 alleles. When patients were grouped into group 1 (*4/*4, *4/*41, *1/*5 and *2/*5) and group 2 (the remaining genotypes), a significant difference in disease-free survival (DFS) was observed between groups (P = 0.016). The mean DFS in group 1 was 95 months in contrast with 119 months in group 2. No significant relationship was found between the CYP2D6 genotype classification and severe, mild or no toxicity (P = 0.2). Nevertheless, severe, and mild toxicity was more frequent among poor metabolizer patients than in patients with a normal metabolizer pattern (18.8 and 43.8% vs. 10.7 and 36%, respectively). In breast cancer, patients treated with adjuvant tamoxifen, non-functional and severely impaired CYP2D6 variants are associated with a worse DFS and with a higher frequency of severe and mild toxicities. Larger studies of the CYP2D6 genotype-clinical outcomes association are needed to complement initial results. PMID:19189210

  2. 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

  3. META-ANALYSIS OF CYP2D6 METABOLIZER PHENOTYPE AND METOPROLOL PHARMACOKINETICS

    PubMed Central

    Blake, CM; Kharasch, ED; Schwab, M; Nagele, P

    2013-01-01

    Metoprolol, a commonly prescribed beta-blocker, is primarily metabolized by cytochrome P450 2D6 (CYP2D6), an enzyme with substantial genetic heterogeneity. Several smaller studies have shown that metoprolol pharmacokinetics is influenced by CYP2D6 genotype and metabolizer phenotype. To increase robustness of metoprolol pharmacokinetic estimates, a systematic review and meta-analysis of pharmacokinetic studies that administered a single oral dose of immediate release metoprolol was performed. Pooled analysis (n= 264) demonstrated differences in peak plasma metoprolol concentration, area under the concentration-time curve, elimination half-life, and apparent oral clearance that were 2.3-, 4.9-, 2.3-, and 5.9-fold between extensive and poor metabolizers, respectively, and 5.3-, 13-, 2.6-, and 15-fold between ultra-rapid and poor metabolizers (all p<0.001). Enantiomer-specific analysis revealed genotype-dependent enantio-selective metabolism, with nearly 40% greater R- vs S-metoprolol metabolism in ultra-rapid and extensive metabolizers. This study demonstrates a marked effect of CYP2D6 metabolizer phenotype on metoprolol pharmacokinetics and confirms enantiomer specific metabolism of metoprolol. PMID:23665868

  4. 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

  5. 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

  6. Effectiveness of clopidogrel dose escalation to normalize active metabolite exposure and antiplatelet effects in CYP2C19 poor metabolizers.

    PubMed

    Horenstein, Richard B; Madabushi, Rajnikanth; Zineh, Issam; Yerges-Armstrong, Laura M; Peer, Cody J; Schuck, Robert N; Figg, William Douglas; Shuldiner, Alan R; Pacanowski, Michael A

    2014-08-01

    Carriers of two copies of the loss-of-function CYP2C19*2 variant convert less clopidogrel into its active metabolite, resulting in diminished antiplatelet responses and higher cardiovascular event rates. To evaluate whether increasing the daily clopidogrel dose in poor metabolizers (PM) overcomes the effect of the CYP2C19 * 2 variant, we enrolled 18 healthy participants in a genotype-stratified, multi-dose, three-period, fixed-sequence crossover study. Six participants with the *1/*1 extensive (EM), *1/*2 intermediate (IM), and *2/*2 poor metabolizer genotypes each received 75 mg, 150 mg, and 300 mg each for 8 days. In each period, maximal platelet aggregation 4 hours post-dose (MPA4) and active metabolite area under the curve (AUC) differed among genotype groups (P < .05 for all). At day 8, PMs needed 300 mg daily and IMs needed 150 mg daily to attain a similar MPA4 as EMs on the 75 mg dose (32.6%, 33.2%, 31.3%, respectively). Similarly, PMs needed 300 mg daily to achieve active metabolite concentrations that were similar to EMs on 75 mg (AUC 37.7 and 33.5 ng h/mL, respectively). These results suggest that quadrupling the usual clopidogrel dose might be necessary to overcome the effect of poor CYP2C19 metabolism. PMID:24710841

  7. 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

  8. Prediction of in vivo clearance and associated variability of CYP2C19 substrates by genotypes in populations utilizing a pharmacogenetics-based mechanistic model.

    PubMed

    Steere, Boyd; Baker, Jessica A Roseberry; Hall, Stephen D; Guo, Yingying

    2015-06-01

    It is important to examine the cytochrome P450 2C19 (CYP2C19) genetic contribution to drug disposition and responses of CYP2C19 substrates during drug development. Design of such clinical trials requires projection of genotype-dependent in vivo clearance and associated variabilities of the investigational drug, which is not generally available during early stages of drug development, but is essential for CYP2C19 substrates with multiple clearance pathways. This study evaluated the utility of pharmacogenetics-based mechanistic modeling in predicting such parameters. Hepatic CYP2C19 activity and variability within genotypes were derived from in vitro S-mephenytoin metabolic activity in genotyped human liver microsomes (N = 128). These data were then used in mechanistic models to predict genotype-dependent disposition of CYP2C19 substrates (i.e., S-mephenytoin, citalopram, pantoprazole, and voriconazole) by incorporating in vivo clearance or pharmacokinetics of wild-type subjects and parameters of other clearance pathways. Relative to the wild-type, the CYP2C19 abundance (coefficient of variation percentage) in CYP2C19*17/*17, *1/*17, *1/*1, *17/null, *1/null, and null/null microsomes was estimated as 1.85 (117%), 1.79 (155%), 1.00 (138%), 0.83 (80%), 0.38 (130%), and 0 (0%), respectively. The subsequent modeling and simulations predicted, within 2-fold of the observed, the means and variabilities of urinary S/R-mephenytoin ratio (36 of 37 genetic groups), the oral clearance of citalopram (9 of 9 genetic groups) and pantoprazole (6 of 6 genetic groups), and voriconazole oral clearance (4 of 4 genetic groups). Thus, relative CYP2C19 genotype-dependent hepatic activity and variability were quantified in vitro and used in a mechanistic model to predict pharmacokinetic variability, thus allowing the design of pharmacogenetics and drug-drug interaction trials for CYP2C19 substrates. PMID:25845826

  9. Genotype-phenotype analysis of CYP2C19 in the Tibetan population and its potential clinical implications in drug therapy

    PubMed Central

    JIN, TIANBO; ZHANG, XIYANG; GENG, TINGTING; SHI, XUGANG; WANG, LI; YUAN, DONGYA; KANG, LONGLI

    2016-01-01

    Cytochrome P450 2C19 (CYP2C19) is a highly polymorphic gene, it codes for a protein responsible for the metabolism of multiple clinically important therapeutic agents. However, there is currently no available data on the distribution of CYP2C19 mutant alleles in the Tibetan population. The aim of the present study was to identify different CYP2C19 mutant alleles and determine their frequencies, along with genotypic frequencies, in the Tibetan population. The whole CYP2C19 gene was amplified and sequenced in 96 unrelated, healthy Tibetans from the Tibet Autonomous Region of China, the promoter region, exons, introns and the 3′-UTR were screened for genetic variants. Three novel genetic polymorphisms in CYP2C19 were detected among a total of 27 different mutations. The allele frequencies of CYP2C19*1A, *1B, *2A, *3A and *17 were 50, 28.13, 15.10, 5.21 and 1.56%, respectively. The most common genotype combinations were CYP2C19*1A/*1B (56.25%) and *1A/*2A (30.21%). One novel non-synonymous mutation (Asn to Lys) in CYP2C19 was identified, and this mutation was predicted to be intolerant and benign by SIFT and PolyPhen-2, respectively. The observations of the present study may have important clinical implications for the use of medications metabolized by CYP2C19 among Tibetans. PMID:26781306

  10. Personalized medicine in breast cancer: tamoxifen, endoxifen, and CYP2D6 in clinical practice.

    PubMed

    Ruddy, Kathryn J; Desantis, Stephen D; Gelman, Rebecca S; Wu, Alan H B; Punglia, Rinaa S; Mayer, Erica L; Tolaney, Sara M; Winer, Eric P; Partridge, Ann H; Burstein, Harold J

    2013-10-01

    Tamoxifen is metabolized into endoxifen, a potent antagonist of the estrogen receptor, in part through cytochrome p450 (CYP) 2D6. Genotypic variation in CYP2D6 affects endoxifen levels, and some have argued that patients who do not efficiently metabolize tamoxifen might wish to consider alternative hormonal treatments. This study evaluated an algorithm in which endoxifen levels and CYP2D6 genotypes were used to make hormonal therapy recommendations for patients on adjuvant tamoxifen for breast cancer. Patients with stage I-III breast cancer who had been taking adjuvant tamoxifen for 8-56 weeks were eligible. At enrollment, baseline whole blood and serum were sent for genotyping by Amplichip and endoxifen measurement, respectively, and endoxifen levels were also measured 3 weeks later. Results were returned to oncologists along with an algorithm-generated treatment recommendation. The algorithm recommended that participants with poor metabolizer genotype and/or baseline endoxifen level <6 ng/mL consider alternative endocrine therapy. A medical record review evaluated actual treatment decisions. Of 99 patients on study, 18 (18 %) had findings that triggered algorithm-based recommendations to consider a change in endocrine therapy due to endoxifen <6 ng/mL (all 18 patients) and/or poor metabolizer CYP2D6 genotype (2 of the 18). Endoxifen levels were ≥6 ng/mL in four of them 3 weeks later. Seven (39 % of 18) switched to a different treatment (one based on toxicity, not the algorithm). Hot flash burden was not found to be significantly associated with endoxifen <6 ng/mL or genotype. Prospective testing of tamoxifen metabolism as gauged by CYP2D6 genotype and serum endoxifen levels is feasible. Future studies of tamoxifen metabolism and efficacy should consider including measurement of serial endoxifen levels. Although clinical evidence at present is insufficient to warrant routine CYP2D6 or endoxifen testing, some clinicians and patients did utilize this

  11. 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. PMID:25187485

  12. An additional defective allele, CYP2C19*5, contributes to the S-mephenytoin poor metabolizer phenotype in Caucasians.

    PubMed

    Ibeanu, G C; Blaisdell, J; Ghanayem, B I; Beyeler, C; Benhamou, S; Bouchardy, C; Wilkinson, G R; Dayer, P; Daly, A K; Goldstein, J A

    1998-04-01

    The metabolism of the anticonvulsant drug mephenytoin exhibits a genetic polymorphism in humans. This polymorphism exhibits marked racial heterogeneity, with the poor metabolizer PM phenotype representing 13-23% of oriental populations, but only 2-5% of Caucasian populations. Two defective CYP2C19 alleles (CYP2C19*2 and CYP2C19*3) have been described, which account for more than 99% of Oriental poor metabolizer alleles but only approximately 87% of Caucasian poor metabolizer alleles. Therefore, additional defects presumably contribute to the poor metabolizer in Caucasians. Recent studies have found a third mutation CYP2C19*4, which accounts for approximately 3% of Caucasian poor metabolizer alleles. A fourth rare mutation (CYP2C19*5A) (C99,A991,Ile331;C1297T,Arg433-->Trp) resulting in an Arg433 to Trp substitution in the heme-binding region has been reported in a single Chinese poor metaboliser outlier belonging to the Bai ethnic group. The present study identifies a second variant allele CYP2C19*5B (C99-->T; A991-->G, Ile331-->Val; C1297-T, Arg433-->Trp in one of 37 Caucasian poor metabolizers. The frequency of the CYP2C19*5 alleles is low in Chinese (approximately 0.25% in the Bai ethnic group) and Caucasians (< 0.9%). However, these alleles contribute to the poor metabolizer phenotype in both ethnic groups and increases the sensitivity of the genetic tests for identifying defective alleles to approximately 100% in Chinese poor metabolizers and 92% in Caucasian poor metabolizers genotyped in our laboratory. The Arg433 to Trp mutation in the heme-binding region essentially abolishes activity of recombinant CYP2C19*5A toward S-mephenytoin and tolbutamide, which is consistent with the conclusion that CYP2C19*5 represents poor metabolizer alleles. PMID:10022751

  13. Design and synthesis of novel tamoxifen analogues that avoid CYP2D6 metabolism.

    PubMed

    Ahmed, Nermin S; Elghazawy, Nehal H; ElHady, Ahmed K; Engel, Matthias; Hartmann, Rolf W; Abadi, Ashraf H

    2016-04-13

    Tamoxifen (TAM) is a widely used drug in the prophylaxis and treatment of breast cancer. TAM is metabolized to the more active 4-hydroxytamoxifen (4-OH-TAM) and endoxifen by cytochrome P450 (CYP) mainly CYP2D6 and CYP3A4 enzymes. Due to the genetic polymorphisms in CYP2D6 genes, high variation in the clinical outcomes of TAM treatment is observed among women of different populations. To address this issue, novel TAM analogues with possible altered activation pathways were synthesized. These analogues were tested for their antiproliferative action on MCF-7 breast cancer cell lines as well as their binding affinity for estrogen receptor (ER) ER-α and ER-β receptors. These entire novel compounds showed better antiproliferative activity than did TAM on the MCF-7 cells. Moreover, compound 10 exhibited a half maximal growth inhibition (GI50) that was 1000 times more potent than that of TAM (GI50 < 0.005 μM vs 1.58 μM, respectively). Along with a broad spectrum activity on various cancer cell lines, all the TAM analogues showed considerable activity on the ER-negative breast cancer cell line. For further study, compound 10 was incubated in human liver microsomes (HLM), human hepatocytes (hHEP) and CYP2D6 supersomes. The active hydroxyl metabolite was detected after incubation in HLM and hHEP, implicating the involvement of other enzymes in its metabolism. These results prove that this novel series of TAM analogues might provide improved clinical outcomes for poor 2D6 metabolizers. PMID:26896706

  14. Anthocyanins and anthocyanidins are poor inhibitors of CYP2D6.

    PubMed

    Dreiseitel, Andrea; Schreier, Peter; Oehme, Anett; Locher, Sanja; Rogler, Gerhard; Piberger, Heidi; Hajak, Goeran; Sand, Philipp G

    2009-01-01

    The cytochrome P450 CYP2D6 isoform is involved in the metabolism of about 50% of all psychoactive drugs, including neuroleptic agents, selective serotonin reuptake inhibitors, selective norepinephrine reuptake inhibitors and tricyclic antidepressants. Therefore, inhibition of cytochrome P450 activity by foodstuffs has implications for drug safety. The present study addresses inhibitory effects of polyphenolic anthocyanins and their aglycons that are found in many dietary fruits and vegetables. Using a chemiluminescent assay, we obtained IC(50) values ranging from 55 microM to > 800 microM for 17 individual compounds. According to earlier data on furanocoumarins from grapefruit extract, CYP2D6 inhibition is achieved in the range of 190-900 nM. As the tested anthocyanins and anthocyanidins were shown to be about 1,000-fold less potent, they are unlikely to interfere with drug metabolism by CYP2D6. Further studies are warranted to examine the effects of the above flavonoids on other CYP isoforms for more detailed toxicity profiles. PMID:19357792

  15. Neuroleptic malignant syndrome in an adolescent with CYP2D6 deficiency.

    PubMed

    Butwicka, Agnieszka; Krystyna, Szymańska; Retka, Włodzimierz; Wolańczyk, Tomasz

    2014-12-01

    We describe a patient with dystonia and psychotic symptoms treated with standard doses of antipsychotics, who developed neuroleptic malignant syndrome (NMS). A 16-year-old male with a history of misuse of dextromethorphan and pseudoephedrine for recreational purpose presented with dystonia and a psychotic episode. Following continuous treatment with olanzapine (10 mg/day), repeated injections of levomepromazine (37.5 mg/day), and a single injection of haloperidol (2.5 mg), the patient developed NMS. Muscular rigidity, fever (up to 41 °C), hypotension (100/70 mmHg), tachycardia (120 beats per minute), tachypnea (26 breaths per minute), elevated leukocyte count (up to 16.6 × 10(3)/μL), and elevated serum creatinine phosphokinase (CPK) (up to 15,255 U/L) were observed. A diagnosis of NMS was made according to the DSM-IV TR criteria. Genotyping revealed that he was homozygous for a non-functional CYP2D6*4 allele. The case highlights the importance of therapeutic drug monitoring in identification and differentiation of drug-induced effects in psychiatric disorder to prevent NMS and its complications. In addition, genotyping of CYP2D6 might be considered in patients with symptoms suggestive of drug toxicity who are treated with neuroleptics metabolized via the CYP2D6 pathway, as carriage of one or more non-functional alleles may increase the risk for adverse reactions, such as NMS. PMID:24253372

  16. 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

  17. 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

  18. 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. PMID:26908082

  19. Primaquine pharmacology in the context of CYP 2D6 pharmacogenomics: Current state of the art.

    PubMed

    Marcsisin, Sean R; Reichard, Gregory; Pybus, Brandon S

    2016-05-01

    Primaquine is the only antimalarial drug available to clinicians for the treatment of relapsing forms of malaria. Primaquine development and usage dates back to the 1940s and has been administered to millions of individuals to treat and eliminate malaria infections. Primaquine therapy is not without disadvantages, however, as it can cause life threatening hemolysis in humans with glucose-6-phosphate dehydrogenase (G6PD) deficiency. In addition, the efficacy of primaquine against relapsing malaria was recently linked to CYP 2D6 mediated activation to an active metabolite, the structure of which has escaped definitive identification for over 75years. CYP 2D6 is highly polymorphic among various human populations adding further complexity to a comprehensive understanding of primaquine pharmacology. This review aims to discuss primaquine pharmacology in the context of state of the art understanding of CYP 2D6 mediated 8-aminoquinoline metabolic activation, and shed light on the current knowledge gaps of 8-aminoquinoline mechanistic understanding against relapsing malaria. PMID:27016470

  20. Acetaldehyde and parkinsonism: role of CYP450 2E1

    PubMed Central

    Vaglini, Francesca; Viaggi, Cristina; Piro, Valentina; Pardini, Carla; Gerace, Claudio; Scarselli, Marco; Corsini, Giovanni Umberto

    2013-01-01

    The present review update the relationship between acetaldehyde (ACE) and parkinsonism with a specific focus on the role of P450 system and CYP 2E1 isozyme particularly. We have indicated that ACE is able to enhance the parkinsonism induced in mice by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, a neurotoxin able to damage the nigrostriatal dopaminergic pathway. Similarly diethyldithiocarbamate, the main metabolite of disulfiram, a drug widely used to control alcoholism, diallylsulfide (DAS) and phenylisothiocyanate also markedly enhance the toxin-related parkinsonism. All these compounds are substrate/inhibitors of CYP450 2E1 isozyme. The presence of CYP 2E1 has been detected in the dopamine (DA) neurons of rodent Substantia Nigra (SN), but a precise function of the enzyme has not been elucidated yet. By treating CYP 2E1 knockout (KO) mice with the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, the SN induced lesion was significantly reduced when compared with the lesion observed in wild-type animals. Several in vivo and in vitro studies led to the conclusion that CYP 2E1 may enhance the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine toxicity in mice by increasing free radical production inside the dopaminergic neurons. ACE is a good substrate for CYP 2E1 enzyme as the other substrate-inhibitors and by this way may facilitate the susceptibility of dopaminergic neurons to toxic events. The literature suggests that ethanol and/or disulfiram may be responsible for toxic parkinsonism in human and it indicates that basal ganglia are the major targets of disulfiram toxicity. A very recent study reports that there are a decreased methylation of the CYP 2E1 gene and increased expression of CYP 2E1 mRNA in Parkinson's disease (PD) patient brains. This study suggests that epigenetic variants of this cytochrome contribute to the susceptibility, thus confirming multiples lines of evidence which indicate a link between environmental toxins and PD. PMID:23801948

  1. A pharmacokinetic comparison of two voriconazole formulations and the effect of CYP2C19 polymorphism on their pharmacokinetic profiles

    PubMed Central

    Chung, Hyewon; Lee, Howard; Han, HyeKyung; An, Hyungmi; Lim, Kyoung Soo; Lee, Yong Jin; Cho, Joo-Youn; Yoon, Seo Hyun; Jang, In-Jin; Yu, Kyung-Sang

    2015-01-01

    Purpose SYP-1018 is a lyophilized polymeric nanoparticle formulation of voriconazole that is under development for intravenous dosing. This study compared the pharmacokinetic and tolerability profiles of SYP-1018 with those of Vfend®, the marketed formulation of voriconazole. The effect of CYP2C19 polymorphism on the voriconazole pharmacokinetics was also evaluated. Methods An open-label, two-treatment, two-period, two-sequence crossover study was conducted in 52 healthy male volunteers, who randomly received a single intravenous infusion of either of the two voriconazole formulations at 200 mg. Blood samples were collected up to 24 hours after drug administration for pharmacokinetic analysis. The plasma concentrations of voriconazole were determined using liquid chromatography with tandem mass spectrometry, and the pharmacokinetic parameters were estimated using a noncompartmental method. CYP2C19 genotype was identified in 51 subjects. Results The geometric mean ratio (90% confidence interval) of SYP-1018 to Vfend® was 0.99 (0.93–1.04) for the maximum plasma concentrations (Cmax) and 0.97 (0.92–1.01) for the area under the concentration–time curve (AUC) from dosing to the last quantifiable concentration (AUClast). Nineteen homozygous extensive metabolizers (EMs, *1/*1), 19 intermediate metabolizers (IMs, *1/*2 or *1/*3), and ten poor metabolizers (PMs, *2/*2, *2/*3, or *3/*3) were identified, and the pharmacokinetic comparability between SYP-1018 and Vfend® was also noted when analyzed separately by genotype. The systemic exposure to voriconazole was greatest in the PM group, followed by the IM, and then the EM groups. Furthermore, the intrasubject variability for Cmax and AUClast was greater in IMs and PMs than in EMs. No serious adverse event occurred, and both treatments were well tolerated. Conclusion SYP-1018 had comparable pharmacokinetic and tolerability profiles to Vfend® after a single intravenous infusion. CYP2C19 genotype affected not only the

  2. The antitussive effect of dextromethorphan in relation to CYP2D6 activity

    PubMed Central

    Abdul Manap, R; Wright, C E; Gregory, A; Rostami-Hodjegan, A; Meller, S T; Kelm, G R; Lennard, M S; Tucker, G T; Morice, A H

    1999-01-01

    Aims To test the hypothesis that inhibition of cytochrome P450 2D6 (CYP2D6) by quinidine increases the antitussive effect of dextromethorphan (DEX) in an induced cough model. Methods Twenty-two healthy extensive metaboliser phenotypes for CYP2D6 were studied according to a double-blind, randomised cross-over design after administration of: (1) Placebo antitussive preceded at 1 h by placebo inhibitor; (2) 30 mg oral DEX preceded at 1 h by placebo inhibitor (DEX30); (3) 60 mg oral DEX preceded at 1 h by placebo inhibitor (DEX60); (4) 30 mg oral DEX preceded at 1 h by 50 mg oral quinidine sulphate (QDEX30). Cough frequency following inhalation of 10% citric acid was measured at baseline and at intervals up to 12 h. Plasma concentrations of DEX and its metabolites were measured up to 96 h by h.p.l.c. Results Inhibition of CYP2D6 by quinidine caused a significant increase in the mean ratio of DEX to dextrorphan (DEX:DOR) plasma AUC(96) (0.04 vs 1.81, P < 0.001). The mean (±s.d.) decrements in cough frequency below baseline over 12 h (AUEC) were: 8% (11), 17% (14.5), 25% (16.2) and 25% (16.9) for placebo, DEX30, DEX60 and QDEX30 treatments, respectively. Statistically significant differences in antitussive effect were detected for the contrasts between DEX60/placebo (P < 0.001; 95% CI of difference +80, +327) and QDEX30/placebo (P < 0.001, +88, +336), but not for DEX30/placebo, DEX30/DEX60 or DEX30/QDEX30 (P = 0.071, −7, +241; P = 0.254, −37, +211; P = 0.187, −29, +219, respectively). Conclusions A significant antitussive effect was demonstrated after 60 mg dextromethorphan and 30 mg dextromethorphan preceded by 50 mg quinidine using an induced cough model. However, although the study was powered to detect a 10% difference in cough response, the observed differences for other contrasts were less than 10%, such that it was possible only to imply a dose effect (30 vs 60 mg) in the antitussive activity of DEX and enhancement of this effect by CYP2D6 inhibition. PMID

  3. 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. PMID:26602992

  4. Comparison of a rapid point-of-care and two laboratory-based CYP2C19*2 genotyping assays for personalisation of antiplatelet therapy.

    PubMed

    Wirth, Francesca; Zahra, Graziella; Xuereb, Robert G; Barbara, Christopher; Fenech, Albert; Azzopardi, Lilian M

    2016-04-01

    Background A quick CYP2C19*2 genotyping assay can be useful in personalised antiplatelet-therapy. Objective To apply a rapid point-of-care (POC) CYP2C19*2 genotyping assay for personalisation of antiplatelet therapy in patients undergoing percutaneous coronary intervention (PCI) and to compare this POC assay to two laboratory-based CYP2C19*2 genotyping assays. Setting Cardiac Catheterisation Suite and Molecular Diagnostics Unit in a general hospital. Methods A buccal sample was collected for POC CYP2C19*2 genotyping with the Spartan™ RX system (Spartan Bioscience). A whole blood sample was collected from the same patients for laboratory-based CYP2C19*2 genotyping with a TaqMan(®) allelic discrimination assay (Life Technologies) using real-time quantitative PCR and with the GenID(®) reverse dot-blot hybridisation assay (Autoimmun Diagnostika GmbH). Each patient was genotyped as a non-carrier of CYP2C19*2 (*1/*1), a carrier of one CYP2C19*2 allele (*1/*2), or a carrier of two CYP2C19*2 alleles (*2/*2). Genotyping, interpretation and communication of genotype results (*1/*2, *2/*2) to the consultant cardiologist was undertaken by a clinical pharmacist researcher. Quantitative and qualitative comparison between the three assays was carried out. Main outcome measures Application of a rapid POC CYP2C19*2 genotyping assay for antiplatelet therapy individualisation; comparison of the POC CYP2C19*2 genotyping assay to two laboratory-based assays. Results The total sample consisted of 34 Caucasian patients. With the POC assay, 21 patients were genotyped as non-carriers of CYP2C19*2, 12 patients as carriers of one CYP2C19*2 allele and one patient as a carrier of two CYP2C19*2 alleles. With both laboratory-based assays, the same 21 patients were genotyped as non-carriers of CYP2C19*2, however 13 patients were genotyped as carriers of one CYP2C19*2 allele and no patients were genotyped as carriers of two CYP2C19*2 alleles. Agreement in genotype results was 97 % (κ = 0

  5. Cytochrome P450 CYP 2C19*2 Associated with Adverse 1-Year Cardiovascular Events in Patients with Acute Coronary Syndrome

    PubMed Central

    Yang, Hao; Cao, Heng

    2015-01-01

    Background The cytochrome P450 (CYP450) 2C19 681 genotypes affect the antiplatelet activity of clopidogrel. We investigated the correlation of CYP 2C19 681G > A mutation with clopidogrel resistance (CR). Additionally, we studied the effect of CR on clinical prognosis of patients with acute coronary syndrome (ACS). Methods One hundred ten ACS patients undergoing percutaneous coronary intervention, who were followed-up for 1 year, were included in the study. The patients were co-administered aspirin 100 mg/d and clopidogrel 75mg/d following a loading dose of 300 mg. CR was assessed on the basis of polymorphism observed in the CYP2C19 subgroup. Results Patients in GG genotype group exhibited greater inhibition of platelet aggregation than patients in GA and AA genotype groups (16.2 ± 10.1%; 10.2 ± 9.9%; 8.0 ± 5.9%, respectively, p < 0.01). CYP2C19 681GG genotype group was associated with lower CR than CYP2C19 681A allele (GA + AA) group (9/59 vs. (12+5)/51; p = 0.009). Over a follow-up of 12 months, the incidence of recurrent angina, acute myocardial infarction, and intra-stent thrombosis in CYP2C19 681 GG carriers was significantly lower than that in CYP2C19 681A allele (GA + AA) group (2/59 vs. 8/51, 1/59 vs. 6/51, 0 vs. 4/51, respectively, p < 0.05). Conclusion CYP 2C19*2 is associated with reduced clopidogrel antiplatelet activity and might be an important marker for poor prognosis of ACS. PMID:26147597

  6. Challenges in CYP2D6 phenotype assignment from genotype data: a critical assessment and call for standardization.

    PubMed

    Hicks, J Kevin; Swen, Jesse J; Gaedigk, Andrea

    2014-02-01

    The cytochrome P450 2D6 (CYP2D6) enzyme contributes to the metabolism and/or bioactivation of approximately 25% of clinically used drugs. The CYP2D6 gene locus is highly polymorphic and complex, and variants within this gene locus affect CYP2D6 enzymatic function resulting in a wide range of metabolic activity from little to no activity to ultrarapid metabolism. For many of the drugs metabolized by CYP2D6, the variation in metabolic activity is one of the most important factors responsible for interindividual drug response. Therefore, determining an individual's CYP2D6 phenotype, or metabolic status, will help identify individuals that may benefit from a change in drug or drug dosage. Genotype analysis has become the method of choice to predict a person's metabolic status. Numerous reference laboratories now offer CYP2D6 genotyping; however, there can be substantial differences in the number of genetic variants interrogated as well as test interpretation. Furthermore, there is no standardized process of how a CYP2D6 genotype result is translated into a phenotype assignment. This review summarizes the complexity of CYP2D6 genotyping and highlights the major challenges for phenotype classification. We call for the implementation of a universally accepted system for CYP2D6 phenotype assignment to promote consistency of test interpretation among reference laboratories and medical institutions. We propose a system that utilizes the CYP2D6 activity score system to place individuals into a continuum of activity scores - rather than using the traditional poor, intermediate, extensive and ultra-rapid metabolizer categorizations - and directly translating activity scores into clinically actionable recommendations. PMID:24524666

  7. 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

  8. 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

  9. Genetic polymorphisms of CYP2C9 and CYP2C19 are not related to drug-induced idiosyncratic liver injury (DILI)

    PubMed Central

    Pachkoria, K; Lucena, M I; Ruiz-Cabello, F; Crespo, E; Cabello, M R; Andrade, R J

    2007-01-01

    Background and purpose: The general view on the pathogenesis of drug-induced idiosyncratic liver injury (DILI) is that parent compounds are rendered hepatotoxic by metabolism, mainly by cytochrome (CYP) 450, although other metabolic pathways can contribute. Anecdotal reports suggest a role of CYP 450 polymorphisms in DILI. We aimed to assess in a series of Spanish DILI patients the prevalence of important allelic variants of CYP2C9 and CYP2C19, known to be involved in the metabolism of several hepatotoxic drugs. Experimental approach: Genotyping of CYP2C9 (*2, *3) and CYP2C19 (*2 and *3), was carried out in a total of 28 and 32 patients with a well established diagnosis of DILI. CYP2C9 and CYP2C19 variants were analysed in genomic DNA by means of PCR-FRET and compared with previous findings in other Caucasian populations. Key results: CYP2C9 and CYP2C19 allele and genotype frequencies were in agreement with Hardy-Weinberg equilibrium. Fourteen patients (50%) were heterozygous and 1(4%) found to be compound heterozygous for the CYP2C9 allele. Seven (22%) were found to carry one and 1(3%) carried two CYP2C19 mutated alleles. No patients were homozygous for *3 allele. The distribution of both CYP2C9 and CYP2C19 allelic variants in DILI patients were similar to those in other Caucasian populations. Patients with variant and those with wild-type alleles did not differ in regard to clinical presentation of DILI, type of injury and outcome. Conclusions and Implications: We find no evidence to support CYP2C9 and CYP2C19 genetic polymorphisms as predictable potential risk factors for DILI. PMID:17279092

  10. 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

  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. PMID:27603206

  12. Cytochrome P450 2D6 Polymorphisms and Predicted Opioid Metabolism in African-American Children with Sickle Cell Disease

    PubMed Central

    Yee, Marianne McPherson; Josephson, Cassandra; Hill, Charles E.; Harrington, Rosiland; Castillejo, Marta-Inés; Ramjit, Ruan; Osunkwo, Ifeyinwa

    2013-01-01

    The opioid medications codeine and hydrocodone, commonly prescribed in sickle cell disease (SCD), require metabolic conversion by cytochrome P450 2D6 (CYP2D6) to morphine and hydromorphone, respectively, to exert their analgesic effects. The CYP2D6 gene is highly polymorphic, with variant alleles that result in decreased, absent, or ultrarapid enzyme activity. Seventy-five children with SCD were tested for CYP2D6 polymorphisms, and metabolic phenotypes were inferred from the genotypes. The most common variant alleles were CYP2D6*2 (normal activity, 28.7%), CYP2D6*17 (reduced activity, 17.3%), CYP2D6*5 (gene deletion, 8.7%), and CYP2D6*4 (absent function, 8.0%). Normal/extensive metabolizer (EM) genotypes were found in 28/75 (37.5%), intermediate metabolism (IM) in 33/75 (44.0%), poor metabolism (PM) in 4/75 (5.3%), ultrarapid metabolism (UM) in 3/75 (4.0%), indeterminate in 6/75 (8.0%). Allele frequencies did not vary significantly among different hemoglobin genotypes. Identification of variant CYP2D6 genotypes may identify individuals with altered metabolism and therefore altered analgesic response to codeine and hydrocodone, thus providing a personalized medicine approach to treatment of pain in SCD. Further pharmacokinetic and pharmacodynamic studies are needed to define the relationship of CYP2D6 and other gene polymorphisms to individual opioid effect in SCD. PMID:23619115

  13. The effects of CYP2D6 and CYP3A activities on the pharmacokinetics of immediate release oxycodone

    PubMed Central

    Samer, CF; Daali, Y; Wagner, M; Hopfgartner, G; Eap, CB; Rebsamen, MC; Rossier, MF; Hochstrasser, D; Dayer, P; Desmeules, JA

    2010-01-01

    Background and purpose: There is high interindividual variability in the activity of drug-metabolizing enzymes catalysing the oxidation of oxycodone [cytochrome P450 (CYP) 2D6 and 3A], due to genetic polymorphisms and/or drug–drug interactions. The effects of CYP2D6 and/or CYP3A activity modulation on the pharmacokinetics of oxycodone remains poorly explored. Experimental approach: A randomized crossover double-blind placebo-controlled study was performed with 10 healthy volunteers genotyped for CYP2D6 [six extensive (EM), two deficient (PM/IM) and two ultrarapid metabolizers (UM)]. The volunteers randomly received on five different occasions: oxycodone 0.2 mg·kg−1 and placebo; oxycodone and quinidine (CYP2D6 inhibitor); oxycodone and ketoconazole (CYP3A inhibitor); oxycodone and quinidine+ketoconazole; placebo. Blood samples for plasma concentrations of oxycodone and metabolites (oxymorphone, noroxycodone and noroxymorphone) were collected for 24 h after dosing. Phenotyping for CYP2D6 (with dextromethorphan) and CYP3A (with midazolam) were assessed at each session. Key results: CYP2D6 activity was correlated with oxymorphone and noroxymorphone AUCs and Cmax (−0.71 < Spearman correlation coefficient ρs < −0.92). Oxymorphone Cmax was 62% and 75% lower in PM than EM and UM. Noroxymorphone Cmax reduction was even more pronounced (90%). In UM, oxymorphone and noroxymorphone concentrations increased whereas noroxycodone exposure was halved. Blocking CYP2D6 (with quinidine) reduced oxymorphone and noroxymorphone Cmax by 40% and 80%, and increased noroxycodone AUC∞ by 70%. Blocking CYP3A4 (with ketoconazole) tripled oxymorphone AUC∞ and reduced noroxycodone and noroxymorphone AUCs by 80%. Shunting to CYP2D6 pathway was observed after CYP3A4 inhibition. Conclusions and implications: Drug–drug interactions via CYP2D6 and CYP3A affected oxycodone pharmacokinetics and its magnitude depended on CYP2D6 genotype. PMID:20590587

  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. 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

  18. Loss of Heterozygosity at the CYP2D6 Locus in Breast Cancer: Implications for Germline Pharmacogenetic Studies

    PubMed Central

    Goetz, Matthew P.; Sun, James X.; Suman, Vera J.; Silva, Grace O.; Perou, Charles M.; Nakamura, Yusuke; Cox, Nancy J.; Stephens, Philip J.; Miller, Vincent A.; Ross, Jeffrey S.; Chen, David; Safgren, Stephanie L.; Kuffel, Mary J.; Ames, Matthew M.; Kalari, Krishna R.; Gomez, Henry L.; Gonzalez-Angulo, Ana M.; Burgues, Octavio; Brauch, Hiltrud B.; Ingle, James N.; Ratain, Mark J.; Yelensky, Roman

    2015-01-01

    Background: Controversy exists regarding the impact of CYP2D6 genotype on tamoxifen responsiveness. We examined loss of heterozygosity (LOH) at the CYP2D6 locus and determined its impact on genotyping error when tumor tissue is used as a DNA source. Methods: Genomic tumor data from the adjuvant and metastatic settings (The Cancer Genome Atlas [TCGA] and Foundation Medicine [FM]) were analyzed to characterize the impact of CYP2D6 copy number alterations (CNAs) and LOH on Hardy Weinberg equilibrium (HWE). Additionally, we analyzed CYP2D6 *4 genotype from formalin-fixed paraffin-embedded (FFPE) tumor blocks containing nonmalignant tissue and buccal (germline) samples from patients on the North Central Cancer Treatment Group (NCCTG) 89-30-52 tamoxifen trial. All statistical tests were two-sided. Results: In TCGA samples (n =627), the CYP2D6 LOH rate was similar in estrogen receptor (ER)–positive (41.2%) and ER-negative (35.2%) but lower in HER2-positive tumors (15.1%) (P < .001). In FM ER+ samples (n = 290), similar LOH rates were observed (40.8%). In 190 NCCTG samples, the agreement between CYP2D6 genotypes derived from FFPE tumors and FFPE tumors containing nonmalignant tissue was moderate (weighted Kappa = 0.74; 95% CI = 0.63 to 0.84). Comparing CYP2D6 genotypes derived from buccal cells to FFPE tumor DNA, CYP2D6*4 genotype was discordant in six of 31(19.4%). In contrast, there was no disagreement between CYP2D6 genotypes derived from buccal cells with FFPE tumors containing nonmalignant tissue. Conclusions: LOH at the CYP2D6 locus is common in breast cancer, resulting in potential misclassification of germline CYP2D6 genotypes. Tumor DNA should not be used to determine germline CYP2D6 genotype without sensitive techniques to detect low frequency alleles and quality control procedures appropriate for somatic DNA. PMID:25490892

  19. 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

  20. Preemptive Pharmacogenomic Testing for Precision Medicine: A Comprehensive Analysis of Five Actionable Pharmacogenomic Genes Using Next-Generation DNA Sequencing and a Customized CYP2D6 Genotyping Cascade.

    PubMed

    Ji, Yuan; Skierka, Jennifer M; Blommel, Joseph H; Moore, Brenda E; VanCuyk, Douglas L; Bruflat, Jamie K; Peterson, Lisa M; Veldhuizen, Tamra L; Fadra, Numrah; Peterson, Sandra E; Lagerstedt, Susan A; Train, Laura J; Baudhuin, Linnea M; Klee, Eric W; Ferber, Matthew J; Bielinski, Suzette J; Caraballo, Pedro J; Weinshilboum, Richard M; Black, John L

    2016-05-01

    Significant barriers, such as lack of professional guidelines, specialized training for interpretation of pharmacogenomics (PGx) data, and insufficient evidence to support clinical utility, prevent preemptive PGx testing from being widely clinically implemented. The current study, as a pilot project for the Right Drug, Right Dose, Right Time-Using Genomic Data to Individualize Treatment Protocol, was designed to evaluate the impact of preemptive PGx and to optimize the workflow in the clinic setting. We used an 84-gene next-generation sequencing panel that included SLCO1B1, CYP2C19, CYP2C9, and VKORC1 together with a custom-designed CYP2D6 testing cascade to genotype the 1013 subjects in laboratories approved by the Clinical Laboratory Improvement Act. Actionable PGx variants were placed in patient's electronic medical records where integrated clinical decision support rules alert providers when a relevant medication is ordered. The fraction of this cohort carrying actionable PGx variant(s) in individual genes ranged from 30% (SLCO1B1) to 79% (CYP2D6). When considering all five genes together, 99% of the subjects carried an actionable PGx variant(s) in at least one gene. Our study provides evidence in favor of preemptive PGx testing by identifying the risk of a variant being present in the population we studied. PMID:26947514

  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. Individual Differences in Metabolic Clearance of S-Warfarin Efficiently Mediated by Polymorphic Marmoset Cytochrome P450 2C19 in Livers.

    PubMed

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

    2016-07-01

    Marmoset cytochrome P450 2C19, highly homologous to human P450 2C9 and 2C19, has been identified in common marmosets (Callithrix jacchus), a nonhuman primate species used in drug metabolism studies. Although genetic variants in human and macaque P450 2C genes account for the interindividual variability in drug metabolism, genetic variants have not been investigated in the marmoset P450 2C19 In this study, sequencing of P450 2C19 in 24 marmosets identified three variants p.[(Phe7Leu; Ser254Leu; Ile469Thr)], which showed substantially reduced metabolic capacity of S-warfarin compared with the wild-type group in vivo and in vitro. Although mean plasma concentrations of R-warfarin in marmosets determined after chiral separation were similar between the homozygous mutant and wild-type groups up to 24 hours after the intravenous and oral administrations of racemic warfarin, S-warfarin depletion from plasma was significantly faster in the three wild-type marmosets compared with the three homozygous mutant marmosets. These variants, cosegregating in the marmosets analyzed, influenced metabolic activities in 18 marmoset liver microsomes because the homozygotes and heterozygotes showed significantly reduced catalytic activities in liver microsomes toward S-warfarin 7-hydroxylation compared with the wild-type group. Kinetic analysis for S-warfarin 7-hydroxylation indicated that the recombinant P450 2C19 Ser254Leu variant would change the metabolic capacity. These results indicated that the interindividual variability of P450 2C-dependent drug metabolism such as S-warfarin clearance is at least partly accounted for by P450 2C19 variants in marmosets, suggesting that polymorphic P450 2C-dependent catalytic functions are relatively similar between marmosets and humans. PMID:27098744

  3. A study on the impact of CYP2C19 genotype and platelet reactivity assay on patients undergoing PCI

    PubMed Central

    Rath, P.C.; Chidambaram, Sundar; Rath, Pallavi; Dikshit, Byomakesh; Naik, Sudhir; Sahoo, Prashant K.; Das, Brajraj; Mahalingam, Mohanshankar; Khandrika, Lakshmipathi; Jain, Jugnu

    2015-01-01

    Background A thorough understanding of the patient's genotype and their functional response to a medication is necessary for improving event free survival. Several outcome studies support this view particularly if the patient is to be started on clopidogrel due to the prevalence of clopidogrel resistance. Such guided therapy has reduced the incidence of Major Adverse Cardiac Events (MACE) after stent implantation. Methods Between August 2013 and August 2014, 200 patients with coronary artery disease undergoing percutaneous coronary intervention (PCI) were prescribed any one of the anti-platelet medications such as clopidogrel, prasugrel or ticagrelor and offered testing to detect CYP2C19 gene mutations along with a platelet reactivity assay (PRA). Intended outcome was modification of anti-platelet therapy defined as either dose escalation of clopidogrel or replacement of clopidogrel with prasugrel or ticagrelor for the patients in clopidogrel arm, and replacement of ticagrelor or prasugrel with clopidogrel if those patients were non-carrier of mutant genes and also if they demonstrated bleeding tendencies in the ticagrelor and prasugrel arms. Conclusion Clopidogrel resistance was observed to be 16.5% in our study population. PRA was useful in monitoring the efficacy of thienopyridines. By having this test, one can be safely maintained on clopidogrel in non-carriers, or with increased dose of clopidogrel in intermediate metabolizers or with newer drugs such as ticagrelor or prasugrel in poor metabolizers. Patients on ticagrelor and prasugrel identified as non-carriers of gene mutations for clopidogrel metabolism could be offered clopidogrel resulting in economic benefits to the patients. Patients at high risk of bleeding were also identified by the PRA. PMID:26071289

  4. 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

  5. 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

  6. Population pharmacokinetic analysis of risperidone and 9-hydroxyrisperidone with genetic polymorphisms of CYP2D6 and ABCB1.

    PubMed

    Yoo, Hee-Doo; Cho, Hea-Young; Lee, Sang-No; Yoon, Hwa; Lee, Yong-Bok

    2012-08-01

    This study estimated the population pharmacokinetics of risperidone and its active metabolite, 9-hydroxyrisperidone, according to genetic polymorphisms in the metabolizing enzyme (CYP2D6) and transporter (ABCB1) genes in healthy subjects. Eighty healthy subjects who received a single oral dose of 2 mg risperidone participated in this study. However, eight subjects with rare genotype variants in CYP2D6 alleles were excluded from the final model built in this study. We conducted the population pharmacokinetic analysis of risperidone and 9-hydroxyrisperidone using a nonlinear mixed effects modeling (NONMEM) method and explored the possible influence of genetic polymorphisms in CYP2D6 alleles and ABCB1 (2677G>T/A and 3435C>T) on the population pharmacokinetics of risperidone and 9-hydroxyrisperidone. A two-compartment model with a first-order absorption and lag time fitted well to serum concentration-time curve for risperidone. 9-hydroxyrisperidone was well described by a one-compartment model as an extension of the parent drug (risperidone) model with first-order elimination and absorption partially from the depot. Significant covariates for risperidone clearance were genetic polymorphisms of CYP2D6*10, including CYP2D6*1/*10 (27.5 % decrease) and CYP2D6*10/*10 (63.8 % decrease). There was significant difference in the absorption rate constant (k ( a )) of risperidone among the CYP2D6*10 genotype groups. In addition, combined ABCB1 3435C>T and CYP2D6*10 genotypes had a significant (P < 0.01) effect on the fraction of metabolite absorbed from the depot. The population pharmacokinetic model of risperidone and 9-hydroxyrisperidone including the genetic polymorphisms of CYP2D6*10 and ABCB1 3435C>T as covariates was successfully constructed. The estimated contribution of genetic polymorphisms in CYP2D6*10 and ABCB1 3435C>T to population pharmacokinetics of risperidone and 9-hydroxyrisperidone suggests the interplay of CYP2D6 and ABCB1 on the pharmacokinetics of

  7. Effects of CYP2D6 Status on Harmaline Metabolism, Pharmacokinetics and Pharmacodynamics, and a Pharmacogenetics-Based Pharmacokinetic Model

    PubMed Central

    Wu, Chao; Jiang, Xi-Ling; Shen, Hong-Wu; Yu, Ai-Ming

    2009-01-01

    Harmaline is a β-carboline alkaloid showing neuroprotective and neurotoxic properties. Our recent studies have revealed an important role for cytochrome P450 2D6 (CYP2D6) in harmaline O-demethylation. This study, therefore, aimed to delineate the effects of CYP2D6 phenotype/genotype on harmaline metabolism, pharmacokinetics (PK) and pharmacodynamics (PD), and to develop a pharmacogenetics mechanism-based compartmental PK model. In vitro kinetic studies on metabolite formation in human CYP2D6 extensive metabolizer (EM) and poor metabolizer (PM) hepatocytes indicated that harmaline O-demethylase activity (Vmax/Km) was about 9-fold higher in EM hepatocytes. Substrate depletion showed mono-exponential decay trait, and estimated in vitro harmaline clearance (CLint, μL/min/106 cells) was significantly lower in PM hepatocytes (28.5) than EM hepatocytes (71.1). In vivo studies in CYP2D6-humanized and wild-type mouse models showed that wild-type mice were subjected to higher and longer exposure to harmaline (5 and 15 mg/kg; i.v. and i.p.), and more severe hypothermic responses. The PK/PD data were nicely described by our pharmacogenetics-based PK model involving the clearance of drug by CYP2D6 (CLCYP2D6) and other mechanisms (CLother), and an indirect response PD model, respectively. Wild-type mice were also more sensitive to harmaline in marble-burying tests, as manifested by significantly lower ED50 and steeper Hill slope. These findings suggest that distinct CYP2D6 status may cause considerable variations in harmaline metabolism, PK and PD. In addition, the pharmacogenetics-based PK model may be extended to define PK difference caused by other polymorphic drug-metabolizing enzyme in different populations. PMID:19445902

  8. Liver/kidney microsomal antibody type 1 targets CYP2D6 on hepatocyte plasma membrane

    PubMed Central

    Muratori, L; Parola, M; Ripalti, A; Robino, G; Muratori, P; Bellomo, G; Carini, R; Lenzi, M; Landini, M; Albano, E; Bianchi, F

    2000-01-01

    BACKGROUND—Liver/kidney microsomal antibody type 1 (LKM1) is the marker of type 2 autoimmune hepatitis (AIH) and is detected in up to 6% of patients with hepatitis C virus (HCV) infection. It recognises linear and conformational epitopes of cytochrome P450IID6 (CYP2D6) and may have liver damaging activity, provided that CYP2D6 is accessible to effector mechanisms of autoimmune attack.
METHODS—The presence of LKM1 in the plasma membrane was investigated by indirect immunofluorescence and confocal laser microscopy of isolated rat hepatocytes probed with 10 LKM1 positive sera (five from patients with AIH and five from patients with chronic HCV infection) and a rabbit polyclonal anti-CYP2D6 serum.
RESULTS—Serum from both types of patient stained the plasma membrane of non-permeabilised cells, where the fluorescent signal could be visualised as discrete clumps. Conversely, permeabilised hepatocytes showed diffuse submembranous/cytoplasmic staining. Adsorption with recombinant CYP2D6 substantially reduced plasma membrane staining and LKM1 immunoblot reactivity. Plasma membrane staining of LKM1 colocalised with that of anti-CYP2D6. Immunoprecipitation experiments showed that a single 50 kDa protein recognised by anti-CYP2D6 can be isolated from the plasma membrane of intact hepatocytes.
CONCLUSIONS—AIH and HCV related LKM1 recognise CYP2D6 exposed on the plasma membrane of isolated hepatocytes. This observation supports the notion that anti-CYP2D6 autoreactivity may be involved in the pathogenesis of liver damage.


Keywords: liver/kidney microsomal antibody type 1; autoimmunity; autoimmune hepatitis; hepatitis C virus infection; confocal microscopy PMID:10716687

  9. Risperidone-associated adverse drug reactions and CYP2D6 polymorphisms in a South African cohort

    PubMed Central

    Dodgen, Tyren M.; Eloff, Arinda; Mataboge, Connie; Roos, Louw (.J.L.).; van Staden, Werdie (.C.W.).; Pepper, Michael S.

    2015-01-01

    Background Contradictory information exists regarding the influence of CYP2D6 polymorphisms on adverse drug reactions (ADRs) (extrapyramidal symptoms (EPS) and weight gain) related to risperidone treatment. This prompted us to evaluate the influence of CYP2D6 genetic variation in a cohort of South African patients who presented with marked movement disorders and/or weight gain while on risperidone treatment. Methods Patients who were experiencing marked risperidone ADRs were recruited from Weskoppies Public Psychiatric Hospital. As poor or intermediate metabolism was expected, comprehensive CYP2D6 sequence variations were evaluated using XL-PCR + Sequencing. Results No statistically significant association was found between CYP2D6 poor metabolism and risperidone ADRs. An inverse relationship between EPS and weight gain was however identified. A novel CYP2D6 allele was identified which is unlikely to affect metabolism based on in silico evaluation. Conclusion CYP2D6 variation appeared not to be a good pharmacogenetic marker for predicting risperidone-related ADRs in this naturalistic South African cohort. Evaluation of a larger cohort would be needed to confirm these observations, including an examination of the role of potential intermediaries between the hypothesised genetic and clinical phenotypes. PMID:26937359

  10. Length of psychiatric hospitalization is correlated with CYP2D6 functional status in inpatients with major depressive disorder

    PubMed Central

    Ruaño, Gualberto; Szarek, Bonnie L; Villagra, David; Gorowski, Krystyna; Kocherla, Mohan; Seip, Richard L; Goethe, John W; Schwartz, Harold I

    2016-01-01

    Aim This study aimed to determine the effect of the CYP2D6 genotype on the length of hospitalization stay for patients treated for major depressive disorder. Methods A total of 149 inpatients with a diagnosis of major depressive disorder at the Institute of Living, Hartford Hospital (CT, USA), were genotyped to detect altered alleles in the CYP2D6 gene. Prospectively defined drug metabolism indices (metabolic reserve, metabolic alteration and allele alteration) were determined quantitatively and assessed for their relationship to length of hospitalization stay. Results Hospital stay was significantly longer in deficient CYP2D6 metabolizers (metabolic reserve <2) compared with functional or suprafunctional metabolizers (metabolic reserve ≥2; 7.8 vs 5.7 days, respectively; p = 0.002). Conclusion CYP2D6 enzymatic functional status significantly affected length of hospital stay, perhaps due to reduced efficacy or increased side effects of the medications metabolized by the CYP2D6 isoenzyme. Functional scoring of CYP2D6 alleles may have a substantial impact on the quality of care, patient satisfaction and the economics of psychiatric treatment. PMID:23734807

  11. 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

  12. Reduced-Function CYP2C19 Genotype and Risk of Adverse Clinical Outcomes Among Patients Treated With Clopidogrel Predominantly for PCI: A Meta-Analysis

    PubMed Central

    Mega, Jessica L.; Simon, Tabassome; Collet, Jean-Philippe; Anderson, Jeffrey L.; Antman, Elliott M.; Bliden, Kevin; Cannon, Christopher P.; Danchin, Nicolas; Giusti, Betti; Gurbel, Paul; Horne, Benjamin D.; Hulot, Jean-Sebastian; Kastrati, Adnan; Montalescot, Gilles; Neumann, Franz-Josef; Shen, Lei; Sibbing, Dirk; Steg, P. Gabriel; Trenk, Dietmar; Wiviott, Stephen D.; Sabatine, Marc S.

    2011-01-01

    Content Clopidogrel, one of the most commonly prescribed medications, is a pro-drug requiring CYP450 biotransformation. Data suggest its pharmacologic effect varies based on CYP2C19 genotype, but there is uncertainty regarding the clinical risk imparted by specific genotypes. Objective In patients treated with clopidogrel, to define the risk of major adverse cardiovascular outcomes among carriers of one (∼26% prevalence in whites) and carriers of two (∼2% prevalence in whites) reduced-function CYP2C19 variants. Data Sources and Study Selection A literature search was conducted (January 2000-August 2010) of the MEDLINE, Cochrane, and EMBASE databases. Genetic studies were included where clopidogrel was initiated in predominantly invasively managed patients in a manner consistent with the current guideline recommendations and where clinical outcomes were ascertained. Data Extraction Investigators from nine studies evaluating CYP2C19 genotype and clinical outcomes in patients treated with clopidogrel contributed the relevant hazard ratios (HRs) and their 95% confidence intervals (CI) for specific cardiovascular outcomes by genotype. Results Among 9685 patients [91.3% of whom underwent percutaneous coronary intervention (PCI) and 54.5% of whom had an acute coronary syndrome (ACS)], 863 experienced the composite endpoint of cardiovascular death, myocardial infarction, or stroke; 84 patients had stent thrombosis among the 5894 evaluated for such. Overall, 71.5% were non-carriers, 26.3% had one, and 2.2% had two CYP2C19 reduced-function alleles. A significantly increased risk of the composite endpoint was evident in both carriers of one (HR 1.55, 95% CI 1.11-2.27, P=0.01) and two (HR 1.76, 95% CI 1.24-2.50, P=0.002) CYP2C19 reduced-function alleles. Similarly, there was a significantly increased risk of stent thrombosis in both carriers of one (HR 2.67, 95% CI 1.69-4.22, P<0.0001) and two (HR 3.97, 95% CI 1.75-9.02, P=0.001) CYP2C19 reduced-function alleles

  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. CYP2C19*2 and Other Allelic Variants Affecting Platelet Response to Clopidogrel Tested by Thrombelastography in Patients with Acute Coronary Syndrome

    PubMed Central

    Liu, Jian; Nie, Xiao-Yan; Zhang, Yong; Lu, Yun; Shi, Lu-Wen; Wang, Wei-Min

    2015-01-01

    Background: To investigate the contributions of CYP2C19 polymorphisms to the various clopidogrel responses tested by thrombelastography (TEG) in Chinese patients with the acute coronary syndrome (ACS). Methods: Patients were screened prospectively with ACS diagnose and were treated with clopidogrel and aspirin dual antiplatelet therapy. CYP2C19 loss of function (LOF) and gain of function (GOF) genotype, adenosine 5′-diphosphate (ADP)-channel platelet inhibition rate (PIR) tested by TEG and the occurrence of 3-month major adverse cardiovascular events and ischemic events were assessed in 116 patients. Results: High on-treatment platelet reactivity (HTPR) prevalence defined by PIR <30% by TEG in ADP-channel was 32.76% (38/116). With respect to the normal wild type, CYP2C19*2, and *3 LOF alleles, and *17 GOF alleles, patients were classified into three metabolism phenotypes: 41.38% were extensive metabolizers (EMs), 56.90% were intermediate metabolizers (IMs), and 1.72% were poor metabolizers (PMs). Of the enrolled patients, 31.47%, 5.17%, and 0.43%, respectively, were carriers of *2, *3, and *17 alleles. The HTPR incidence differed significantly according to CYP2C19 genotypes, accounting for 18.75%, 41.54%, and 100.00% in EMs, IMs, and PMs, respectively. Eighteen (17.24%) ischemic events occurred during the 3-month follow-up, and there was a significant difference in ischemic events between HTPR group and nonhigh on-treatment platelet reactivity group. Conclusions: Genetic CYP2C19 polymorphisms are relative to the inferior, the antiplatelet activity after clopidogrel admission and may increase the incidence of ischemic events in patients with ACS. PMID:26265611

  15. 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

  16. Prediction of CYP2D6 drug interactions from in vitro data: evidence for substrate-dependent inhibition.

    PubMed

    VandenBrink, Brooke M; Foti, Robert S; Rock, Dan A; Wienkers, Larry C; Wahlstrom, Jan L

    2012-01-01

    Predicting the magnitude of potential drug-drug interactions is important for underwriting patient safety in the clinical setting. Substrate-dependent inhibition of cytochrome P450 enzymes may confound extrapolation of in vitro results to the in vivo situation. However, the potential for substrate-dependent inhibition with CYP2D6 has not been well characterized. The inhibition profiles of 20 known inhibitors of CYP2D6 were characterized in vitro against four clinically relevant CYP2D6 substrates (desipramine, dextromethorphan, metoprolol, and thioridazine) and bufuralol. Dextromethorphan exhibited the highest sensitivity to in vitro inhibition, whereas metoprolol was the least sensitive. In addition, when metoprolol was the substrate, inhibitors with structurally constrained amino moieties (clozapine, debrisoquine, harmine, quinidine, and yohimbine) exhibited at least a 5-fold decrease in inhibition potency when results were compared with those for dextromethorphan. Atypical inhibition kinetics were observed for these and other inhibitor-substrate pairings. In silico docking studies suggested that interactions with Glu216 and an adjacent hydrophobic binding pocket may influence substrate sensitivity and inhibition potency for CYP2D6. The in vivo sensitivities of the clinically relevant CYP2D6 substrates desipramine, dextromethorphan, and metoprolol were determined on the basis of literature drug-drug interaction (DDI) outcomes. Similar to the in vitro results, dextromethorphan exhibited the highest sensitivity to CYP2D6 inhibition in vivo. Finally, the magnitude of in vivo CYP2D6 DDIs caused by quinidine was predicted using desipramine, dextromethorphan, and metoprolol. Comparisons of the predictions with literature results indicated that the marked decrease in inhibition potency observed for the metoprolol-quinidine interaction in vitro translated to the in vivo situation. PMID:21976621

  17. Aberrant CYP2D6 metabolizer phenotypes do not show increased frequency in patients undergoing ECT after antidepressant therapy.

    PubMed

    Mirzakhani, Hooman; van Dormolen, Juliët; van der Weide, Karen; Guchelaar, Henk-Jan; van Noorden, Martijn S; Swen, Jesse

    2015-10-01

    We investigated the accumulation of aberrant CYP2D6 genotypes and predicted metabolizer phenotypes (ultrarapid metabolizer, intermediate metabolizer and poor metabolizer) potentially affecting the antidepressant treatment response in depressive patients indicated for electroconvulsive therapy (ECT) compared with patients with a single episode of depression. Seventy-six Dutch White patients with unipolar or bipolar treatment-resistant depression who underwent ECT were genotyped using the Amplichip CYP450 Test for CYP2D6. Two hundred and eight patients with a single episode of unipolar or bipolar depression were used as controls. No difference was observed in the prevalence of CYP2D6 phenotypes (poor metabolizer, intermediate metabolizer, extensive metabolizer and ultrarapid metabolizer) between the ECT and the control patients (5.3, 38.7, 56.0 and 0.0% vs. 6.4, 51.0, 42.6 and 0.0%, respectively). The types of depression (odds ratio = 0.33, P = 0.018) and age (odds ratio = 1.55 for a 10-year increase, P < 0.001), but not CYP2D6 phenotype or activity score were associated with the response to antidepressant treatment. In conclusion, preemptive genotyping for CYP2D6 currently appears to have no clinical implications in treatment-resistant depressive patients indicated for ECT. PMID:26230381

  18. 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. PMID:21842479

  19. Dose-dependent effect of the CYP2D6 genotype on the steady-state fluvoxamine concentration.

    PubMed

    Watanabe, Junzo; Suzuki, Yutaro; Fukui, Naoki; Sugai, Takuro; Ono, Shin; Inoue, Yoshimasa; Someya, Toshiyuki

    2008-12-01

    Several studies have reported that the cytochrome P450 (CYP) 2D6 plays an important role in the fluvoxamine metabolism. However, some other studies have reported that the CYP2D6 genotype has no major impact on the fluvoxamine concentration. This study investigated the dose-dependent effect of CYP2D6-variant alleles on the steady-state fluvoxamine concentration. There were 23 patients whose plasma concentrations of fluvoxamine were measured at 4 doses (50, 100, 150, and 200 mg/d). The differences in the plasma fluvoxamine concentration were analyzed between 2 genotype groups divided by the number of CYP2D6-variant alleles (with 0 and 1 or 2 variant alleles). The results demonstrated the nonlinear kinetics of fluvoxamine metabolism, and the degree of nonlinear kinetics decreased as the dose was increased. Significant differences in fluvoxamine concentration were observed between the subjects with 0 variant alleles and the subjects with 1 or 2 variant alleles (P = 0.044) when they were treated by 50 mg of fluvoxamine. There were no significant differences in the plasma concentration of fluvoxamine at 100, 150, and 200 mg/d. The present study suggests that the effect of the CYP2D6 genotype on fluvoxamine metabolism is greater at lower doses of fluvoxamine. PMID:18978520

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

    PubMed

    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

    2016-05-01

    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

  1. 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

  2. CYP2D6 genotype- and endoxifen-guided tamoxifen dose escalation increases endoxifen serum concentrations without increasing side effects.

    PubMed

    Dezentjé, V O; Opdam, F L; Gelderblom, H; Hartigh den, J; Van der Straaten, T; Vree, R; Maartense, E; Smorenburg, C H; Putter, H; Dieudonné, A S; Neven, P; Van de Velde, C J H; Nortier, J W R; Guchelaar, H-J

    2015-10-01

    Breast cancer patients with absent or reduced CYP2D6 activity and consequently low endoxifen levels may benefit less from tamoxifen treatment. CYP2D6 poor and intermediate metabolizers may need a personalized increased tamoxifen dose to achieve effective endoxifen serum concentrations, without increasing toxicity. From a prospective study population of early breast cancer patients using tamoxifen (CYPTAM: NTR1509), 12 CYP2D6 poor and 12 intermediate metabolizers were selected and included in a one-step tamoxifen dose escalation study during 2 months. The escalated dose was calculated by multiplying the individual's endoxifen level at baseline relative to the average endoxifen concentration observed in CYP2D6 extensive metabolizers by 20 mg (120 mg maximum). Endoxifen levels and tamoxifen toxicity were determined at baseline and after 2 months, just before patients returned to the standard dose of 20 mg. Tamoxifen dose escalation in CYP2D6 poor and intermediate metabolizers significantly increased endoxifen concentrations (p < 0.001; p = 0.002, respectively) without increasing side effects. In intermediate metabolizers, dose escalation increased endoxifen to levels comparable with those observed in extensive metabolizers. In poor metabolizers, the mean endoxifen level increased from 24 to 81 % of the mean concentration in extensive metabolizers. In all patients, the endoxifen threshold of 5.97 ng/ml (=16.0 nM) reported by Madlensky et al. was reached following dose escalation. CYP2D6 genotype- and endoxifen-guided tamoxifen dose escalation increased endoxifen concentrations without increasing short-term side effects. Whether such tamoxifen dose escalation is effective and safe in view of long-term toxic effects is uncertain and needs to be explored. PMID:26369533

  3. Stimulus control by 5methoxy-N,N-dimethyltryptamine in wild-type and CYP2D6-humanized mice

    PubMed Central

    Winter, J. C.; Amorosi, D. J.; Rice, Kenner C.; Cheng, Kejun; Yu, Ai-Ming

    2011-01-01

    In previous studies we have observed that, in comparison with wild type mice, Tg-CYP2D6 mice have increased serum levels of bufotenine [5-hydroxy-N,N-dimethyltryptamine] following the administration of 5-MeO-DMT. Furthermore, following the injection of 5-MeO-DMT, harmaline was observed to increase serum levels of bufotenine and 5-MeO-DMT in both wild-type and Tg-CYP2D6 mice. In the present investigation, 5-MeO-DMT-induced stimulus control was established in wild-type and Tg-CYP2D6 mice. The two groups did not differ in their rate of acquisition of stimulus control. When tested with bufotenine, no 5-MeO-DMT-appropriate responding was observed. In contrast, the more lipid soluble analog of bufotenine, acetylbufotenine, was followed by an intermediate level of responding. The combination of harmaline with 5-MeO-DMT yielded a statistically significant increase in 5-MeO-DMT-appropriate responding in Tg-CYP2D6 mice; a comparable increase occurred in wild-type mice. In addition, it was noted that harmaline alone was followed by a significant degree of 5-MeO-DMT-appropriate responding in Tg-CYP2D6 mice. It is concluded that wild-type and Tg-CYPD2D6 mice do not differ in terms of acquisition of stimulus control by 5-MeO-DMT or in their response to bufotenine and acetylbufotenine. In both groups of mice, harmaline was found to enhance the stimulus effects of 5-MeO-DMT. PMID:21624387

  4. Stimulus control by 5-methoxy-N,N-dimethyltryptamine in wild-type and CYP2D6-humanized mice.

    PubMed

    Winter, J C; Amorosi, D J; Rice, Kenner C; Cheng, Kejun; Yu, Ai-Ming

    2011-09-01

    In previous studies we have observed that, in comparison with wild type mice, Tg-CYP2D6 mice have increased serum levels of bufotenine [5-hydroxy-N,N-dimethyltryptamine] following the administration of 5-MeO-DMT. Furthermore, following the injection of 5-MeO-DMT, harmaline was observed to increase serum levels of bufotenine and 5-MeO-DMT in both wild-type and Tg-CYP2D6 mice. In the present investigation, 5-MeO-DMT-induced stimulus control was established in wild-type and Tg-CYP2D6 mice. The two groups did not differ in their rate of acquisition of stimulus control. When tested with bufotenine, no 5-MeO-DMT-appropriate responding was observed. In contrast, the more lipid soluble analog of bufotenine, acetylbufotenine, was followed by an intermediate level of responding. The combination of harmaline with 5-MeO-DMT yielded a statistically significant increase in 5-MeO-DMT-appropriate responding in Tg-CYP2D6 mice; a comparable increase occurred in wild-type mice. In addition, it was noted that harmaline alone was followed by a significant degree of 5-MeO-DMT-appropriate responding in Tg-CYP2D6 mice. It is concluded that wild-type and Tg-CYPD2D6 mice do not differ in terms of acquisition of stimulus control by 5-MeO-DMT or in their response to bufotenine and acetylbufotenine. In both groups of mice, harmaline was found to enhance the stimulus effects of 5-MeO-DMT. PMID:21624387

  5. Pharmacokinetics and bioequivalence evaluation of risperidone in healthy male subjects with different CYP2D6 genotypes.

    PubMed

    Cho, Hea-Young; Lee, Yong-Bok

    2006-06-01

    The aim of this study was to evaluate the bioequivalence of risperidone in healthy male subjects representing different CYP2D6 genotypes with respect to risperidone, 9-hydroxyrisperidone (9-OH-risperidone), and active moiety. A total of 506 Korean subjects were genotyped for CYP2D6*10 by means of allele-specific polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Based on the genotype analysis, 24 subjects, 7 homozygous for CYP2D6*1, 10 for *10, and 7 heterozygous for *10, were recruited and received a single oral dose of 2 mg risperidone tablet in this study. Serum concentrations of risperidone and 9-OHrisperidone up to 48 h were simultaneously determined. There were no significant differences of the active moiety, risperidone, and 9-OH-risperidone between the two preparations in AUC0-proportinal to, and Cmax. The 90% confidence intervals (CIs) for the ratio of means of the log-transformed AUC0-proportional to. and Cmax for the active moiety, risperidone, and 9-OH-risperidone were all within the bioequivalence acceptance criteria of 0.80-1.25. The CYP2D6*10 allele particularly was associated with higher serum concentrations of risperidone and the risperidone/9-OH-risperidone ratio compared with the CYP2D6*1 allele. The results demonstrate that the two preparations of risperidone are bioequivalent and it can be assumed that they are therapeutically equivalent and exchangeable in clinical practice. Furthermore, the pharmacokinetic parameters of risperidone and the risperidone/9-OH-risperidone ratio are highly dependent on the CYP2D6 genotypes. PMID:16833023

  6. CYP2D6*2 Polymorphism as a Predictor of Failed Outpatient Tramadol Therapy in Postherpetic Neuralgia Patients.

    PubMed

    Nasare, Namita Vilas; Banerjee, Basu Dev; Suryakantrao Deshmukh, Pravin; Mediratta, Pramod Kumari; Saxena, Ashok Kumar; Ahmed, Rafat Sultana; Bhattacharya, Sambit Nath

    2016-01-01

    Human cytochrome P4502D6 (CYP2D6) gene is highly polymorphic, leading to wide interindividual ethnic differences in CYP2D6-mediated drug metabolism. Its activity ranges from complete deficiency to excessive activity, potentially causing toxicity of the medication or therapeutic failure with recommended drug dosages. The aim of the study was to find the association of CYP2D6*2 polymorphisms with demographic characters (age, sex, and weight), pain intensity scales [numerical rating scale (NRS) sleep, global perceived effect (GPE)], and adverse drug effects in postherpetic neuralgia (PHN) patients receiving tramadol. The study comprised 246 patients [including 123 nonresponders (NRs) and 123 responders (Rs)] with PHN undergoing analgesic treatment at the pain clinic, Out Patient Department, University College of Medical Sciences, Guru Teg Bahadur Hospital, Delhi, India. Patients with any history of diabetes mellitus, human immunodeficiency virus, malignancy, hematological or liver disease, psychiatric illness, alcohol abuse, and tramadol sensitivity were excluded from the study. The NRSs of (resting and movement), NRS-sleep, and GPE were evaluated by the treating physician. Adverse drug effects during the time of the study were recorded. All samples were analyzed for CYP2D6*2 polymorphism using the polymerase chain reaction-restriction fragment length polymorphism method. The genotype distribution did not vary significantly among genders [NR (P = 0.723); R (P = 0.947)] and different age groups in NRs (P = 0.763) and Rs (P = 0.268). Clinically, statistically significant (P < 0.001) results were obtained in both the groups when compared with baseline in the NRS-sleep and GPE scores, whereas no association was found between NRS-sleep and GPE scores when compared with CYP2D6*2 genotype (P > 0.05). In addition, CYP2D6*2 genotype was not related to the adverse effects of analgesic therapy. The overall results suggested that CYP2D6*2 polymorphism plays no role in the PHN

  7. Lack of cytochrome P450 2E1 (CYP2E1) induction in the rat liver by starvation without coprophagy.

    PubMed

    Chung, H C; Sung, S H; Kim, J S; Kim, Y C; Kim, S G

    2001-03-01

    Starvation potentiates the hepatotoxicity of a variety of small molecules, including chlorinated hydrocarbons and nitrosamines, through the induction of CYP2E1. A change in CYP2E1 expression during starvation may also alter the pharmacokinetic profiles of xenobiotics. Northern blot and Western blot analyses revealed that hepatic CYP2E1 was not induced during starvation in rats placed in metabolic or wire-bottom cages in contrast to the induction of CYP2E1 in animals housed in solid-bottom cages. We studied the effect of coprophagy on the expression of hepatic CYP2E1 during starvation. The extent of coprophagy was 24% in fed rats. Fecal matter of starving rats was reduced to 14% of control and starving rats re-ingested ~1.6 g of feces per day. The effect of fecal matter on CYP2E1 expression (i.e., 1.6 g/kg/day for 3 days) was assessed in fed or starving rats. Starving rats gavaged with fecal matter for 3 days resulted in a 3.5-fold increase in the level of CYP2E1 mRNA, while fed rats gavaged with feces failed to show an increase in the mRNA. The increase in the CYP2E1 mRNA level accompanied the induction of CYP2E1. Starving rats gavaged with methanol extract of feces (500 mg/kg/day for 3 days) showed a 3.3-fold increase in CYP2E1 mRNA level in the liver. These results provide evidence that CYP2E1 is not induced by starvation without coprophagy, raising the contention that the mechanistic basis for CYP2E1 induction by starvation should be reevaluated. PMID:11181486

  8. Identification and in silico prediction of metabolites of the model compound, tebufenozide by human CYP3A4 and CYP2C19.

    PubMed

    Shirotani, Naoki; Togawa, Moe; Ikushiro, Shinichi; Sakaki, Toshiyuki; Harada, Toshiyuki; Miyagawa, Hisashi; Matsui, Masayoshi; Nagahori, Hirohisa; Mikata, Kazuki; Nishioka, Kazuhiko; Hirai, Nobuhiro; Akamatsu, Miki

    2015-10-15

    The metabolites of tebufenozide, a model compound, formed by the yeast-expressed human CYP3A4 and CYP2C19 were identified to clarify the substrate recognition mechanism of the human cytochrome P450 (CYP) isozymes. We then determined whether tebufenozide metabolites may be predicted in silico. Hydrogen abstraction energies were calculated with the density functional theory method B3LYP/6-31G(∗). A docking simulation was performed using FRED software. Several alkyl sites of tebufenozide were hydroxylated by CYP3A4 whereas only one site was modified by CYP2C19. The accessibility of each site of tebufenozide to the reaction center of CYP enzymes and the susceptibility of each hydrogen atom for metabolism by CYP enzymes were evaluated by a docking simulation and hydrogen abstraction energy estimation, respectively. PMID:26404412

  9. Switching from prasugrel to clopidogrel based on Cytochrome P450 2C19 genotyping in East Asian patients stabilized after acute myocardial infarction.

    PubMed

    Lee, Ji Hyun; Ahn, Sung Gyun; Lee, Jun-Won; Youn, Young Jin; Ahn, Min-Soo; Kim, Jang-Young; Yoo, Byung-Su; Lee, Seung-Hwan; Yoon, Junghan; Kim, Juwon; Choi, Eunhee; Yoo, Sang-Yong; Hung, Olivia Y; Samady, Habib

    2016-06-01

    To evaluate the pharmacodynamic efficacy of de-escalating P2Y12 inhibition from prasugrel to clopidogrel based on cytochrome P450 (CYP) 2C19 genotyping, we genotyped 50 Korean patients with AMI who underwent percutaneous coronary intervention (PCI) for CYP2C19 *2,*3, or *17 using real-time PCR. They were discharged on prasugrel 10 mg daily. A control group of 48 AMI patients who underwent PCI and were discharged on clopidogrel but did not undergo genotyping was identified retrospectively. Based on genotyping results available at 3 weeks, 12 patients found to have 2 copies of either CYP2C19 *2 or *3 loss of function alleles continued prasugrel while the remaining 38 patients switched to clopidogrel 75 mg daily. The rate of patients within the therapeutic window (TW) of on-treatment platelet reactivity (OPR), 852C19 genotyping may improve likelihood of achieving a TW of OPR compared to fixed dose of prasugrel 10 mg during maintenance periods of AMI in East Asians. PMID:26556524

  10. In Vitro Hepatic Metabolism Explains Higher Clearance of Voriconazole in Children versus Adults: Role of CYP2C19 and Flavin-Containing Monooxygenase 3

    PubMed Central

    Yanni, Souzan B.; Annaert, Pieter P.; Augustijns, Patrick; Ibrahim, Joseph G.; Benjamin, Daniel K.

    2010-01-01

    Voriconazole is a broad spectrum antifungal agent for treating life-threatening fungal infections. Its clearance is approximately 3-fold higher in children compared with adults. Voriconazole is cleared predominantly via hepatic metabolism in adults, mainly by CYP3A4, CYP2C19, and flavin-containing monooxygenase 3 (FMO3). In vitro metabolism of voriconazole by liver microsomes prepared from pediatric and adult tissues (n = 6/group) mirrored the in vivo clearance differences in children versus adults, and it showed that the oxidative metabolism was significantly faster in children compared with adults as indicated by the in vitro half-life (T1/2) of 33.8 ± 15.3 versus 72.6 ± 23.7 min, respectively. The Km for voriconazole metabolism to N-oxide, the major metabolite formed in humans, by liver microsomes from children and adults was similar (11 ± 5.2 versus 9.3 ± 3.6 μM, respectively). In contrast, apparent Vmax was approximately 3-fold higher in children compared with adults (120.5 ± 99.9 versus 40 ± 13.9 pmol/min/mg). The calculated in vivo clearance from in vitro data was found to be approximately 80% of the observed plasma clearance values in both populations. Metabolism studies in which CYP3A4, CYP2C19, or FMO was selectively inhibited provided evidence that contribution of CYP2C19 and FMO toward voriconazole N-oxidation was much greater in children than in adults, whereas CYP3A4 played a larger role in adults. Although expression of CYP2C19 and FMO3 is not significantly different in children versus adults, these enzymes seem to contribute to higher metabolic clearance of voriconazole in children versus adults. PMID:19841059

  11. Efficacy and safety of voriconazole and CYP2C19 polymorphism for optimised dosage regimens in patients with invasive fungal infections.

    PubMed

    Wang, Taotao; Zhu, Huifang; Sun, Jinyao; Cheng, Xiaoliang; Xie, Jiao; Dong, Haiyan; Chen, Limei; Wang, Xue; Xing, Jianfeng; Dong, Yalin

    2014-11-01

    The aim of this study was to determine an optimum voriconazole target concentration, to study the influence of CYP2C19 gene status on metabolism of voriconazole and to identify a dose-adjustment strategy for voriconazole according to CYP2C19 polymorphism in patients with invasive fungal infections. A total of 328 voriconazole trough plasma concentrations (C(min)) were collected and monitored from 144 patients. Information on efficacy and safety was obtained. Voriconazole therapy was effective in 81.9% of patients (118/144), and 12.5% (18/144) exhibited signs of hepatotoxicity. The relationships between voriconazole C(min) and clinical response and hepatotoxicity were explored using logistic regression, and a target clinical C(min) range of 1.5-4 mg/L was identified. Values of voriconazole C(min) and the ratio of C(min) to concentration of voriconazole-N-oxide (C(min)/C(N)) of poor metabolisers (PMs) were significantly higher than extensive metabolisers and intermediate metabolisers. Model-based simulations showed that PM patients could be safely and effectively treated with 200 mg twice daily orally or intravenously, and non-PM patients with 300 mg twice daily orally or 200mg twice daily intravenously. This study highlighted that voriconazole C(min) and C(min)/C(N) are strongly influenced by CYP2C19 polymorphism, and gene-adjusted dosing is important to achieve therapeutic levels that maximise therapeutic response and minimise hepatotoxicity. PMID:25239277

  12. Frequency distribution of polymorphisms of CYP2C19, CYP2C9, VKORC1 and SLCO1B1 genes in the Yakut population

    PubMed Central

    Vasilyev, Filipp Filippovich; Danilova, Diana Aleksandrovna; Kaimonov, Vladimir Sergeevich; Chertovskih, Yana Valerievna; Maksimova, Nadezda Romanovna

    2016-01-01

    Allele frequencies of single nucleotide polymorphisms (SNPs) are variable among different populations; therefore the study of SNPs in ethnic groups is important for establishing the clinical significance of the screening of these polymorphisms. The main goal of the research is to study the polymorphisms of CYP2C9, CYP2C19, VKORC1, and SLCO1B1 in Yakuts. Genomic DNA from 229 Yakut subjects were analyzed by real-time polymerase chain reaction (PCR) (SLCO1B1 +521T > C, VKORC1 -1639G>A, CYP2C19 +681G>A, +636G>A, CYP2C9 +430С>T, +1075A>C). Genotype frequencies of polymorphisms in the population of the Yakuts were more characteristic of the Asian population. The results have been included in the software application “Lekgen” that we developed for the interpretation of pharmacogenetic testing. The data of our study obtained on frequency carriers of polymorphisms of genes SLCO1B1, CYP2C19, CYP2C9, VKORC1 among the Yakuts may be useful in developing recommendations for a personalized therapy.

  13. Genetic Polymorphism of CYP2D6 and Clomiphene Concentrations in Infertile Patients with Ovulatory Dysfunction Treated with Clomiphene Citrate

    PubMed Central

    2016-01-01

    CYP2D6 is primarily responsible for the metabolism of clomiphene citrate (CC). The purpose of the present study was to investigate the relationship between CYP2D6 genotypes, concentrations of CC and its major metabolites and drug response in infertility patients. We studied 42 patients with ovulatory dysfunction treated with only CC. Patients received a dose of 100 mg/day CC on days 3-7 of the menstrual cycle. CYP2D6 genotyping and measurement of CC and the major metabolite concentrations were performed. Patients were categorized into CC responders or non-responders according to one cycle response for the ovulation. Thirty-two patients were CC responders and 10 patients were non-responders with 1 cycle treatment. The CC concentrations were highly variable within the same group, but non-responders revealed significantly lower (E)-clomiphene concentration and a trend of decreased concentrations of active metabolites compared to the responders. Nine patients with intermediate metabolizer phenotype were all responders. We confirmed that the CC and the metabolite concentrations were different according to the ovulation status. However, our results do not provide evidence for the contribution of CYP2D6 polymorphism to either drug response or CC concentrations. PMID:26839488

  14. Non-alcoholic fatty liver disease (NAFLD) potentiates autoimmune hepatitis in the CYP2D6 mouse model.

    PubMed

    Müller, Peter; Messmer, Marie; Bayer, Monika; Pfeilschifter, Josef M; Hintermann, Edith; Christen, Urs

    2016-05-01

    Non-alcoholic fatty liver disease (NAFLD) and its more severe development non-alcoholic steatohepatitis (NASH) are increasing worldwide. In particular NASH, which is characterized by an active hepatic inflammation, has often severe consequences including progressive fibrosis, cirrhosis, and eventually hepatocellular carcinoma (HCC). Here we investigated how metabolic liver injury is influencing the pathogenesis of autoimmune hepatitis (AIH). We used the CYP2D6 mouse model in which wild type C57BL/6 mice are infected with an Adenovirus expressing the major liver autoantigen cytochrome P450 2D6 (CYP2D6). Such mice display several features of human AIH, including interface hepatitis, formation of LKM-1 antibodies and CYP2D6-specific T cells, as well as hepatic fibrosis. NAFLD was induced with a high-fat diet (HFD). We found that pre-existing NAFLD potentiates the severity of AIH. Mice fed for 12 weeks with a HFD displayed increased cellular infiltration of the liver, enhanced hepatic fibrosis and elevated numbers of liver autoantigen-specific T cells. Our data suggest that a pre-existing metabolic liver injury constitutes an additional risk for the severity of an autoimmune condition of the liver, such as AIH. PMID:26924542

  15. Mechanism-based inhibition of CYP3A4 and CYP2D6 by Indonesian medicinal plants.

    PubMed

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

    2006-05-24

    Thirty samples of Indonesian medicinal plants were tested for their mechanism-based inhibition on cytochrome P450 3A4 (CYP3A4) and CYP2D6 via erythromycin N-demethylation and dextromethorphan O-demethylation activities in human liver microsomes. From screening with 0 and 20min preincubation at 0.5mg/ml of methanol extracts, five plants (Cinnamomum burmani bark, Foeniculum vulgare seed, Strychnos ligustrina wood, Tinospora crispa stem, and Zingiber cassumunar rhizome) showed more than 30% increase of CYP3A4 inhibition, while three (Alpinia galanga rhizome, Melaleuca leucadendron leaf, and Piper nigrum fruit) showed more than 30% increase of CYP2D6 inhibition. In these eight plants, Foeniculum vulgare seed, Cinnamomum burmani bark, and Strychnos ligustrina wood showed time-dependent inhibition on CYP3A4 and Piper nigrum fruit and Melaleuca leucadendron leaf on CYP2D6. Among these, four plants other than Melaleuca leucadendron revealed NADPH-dependent inhibition. Thus, Foeniculum vulgare, Cinnamomum burmani, and Strychnos ligustrina should contain mechanism-based inhibitors on CYP3A4 and Piper nigrum contain that on CYP2D6. PMID:16414224

  16. Relationship between genotypes Sult1a2 and Cyp2d6 and tamoxifen metabolism in breast cancer patients.

    PubMed

    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

  17. 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

  18. ABCB1 C3435T and CYP2C19*2 polymorphisms in a Palestinian and Turkish population: A pharmacogenetic perspective to clopidogrel

    PubMed Central

    Nassar, Suheir; Amro, Omar; Abu-Rmaileh, Hilal; Alshaer, Inji; Korachi, May; Ayesh, Suhail

    2014-01-01

    Clopidogrel is an antiplatelet drug used to prevent recurrent ischemic events after acute coronary syndrome and/or coronary stent implantation. Single nucleotide polymorphisms (SNPs) such as CYP2C19*2 and ABCB1 C3435T have been found to play a role in different individual responses to clopidogrel. Since the prevalence of these SNPs is generally known to differ from one population to another, the aim of this study was to examine their prevalence in both a Palestinian and Turkish population. One hundred unrelated Palestinian subjects and 100 unrelated Turkish subjects were analyzed for CYP2C19*2 and ABCB1 C3435T polymorphisms by the amplification refractory mutation system (ARMS). Results showed an ABCB1 3435 T allele frequency of 0.46 (95% CI 0.391 to 0.529) in the Palestinian sample and 0.535 (95% CI 0.4664 to 0.6036) in the Turkish sample. CYP2C19*2 allele frequency was 0.095 (95% CI 0.0558 to 0.134) in the Palestinian sample and 0.135 (95% CI 0.088 to 0.182) in the Turkish sample. Our results provide information about the prevalence of the polymorphisms related to clopidogrel response in both the Palestinian and Turkish populations, in order to improve the safety and efficacy of clopidogrel through use of genetically guided, individualized treatment. The prevalence of these clinically significant alleles shed light on the importance of testing them before prescribing clopidogrel. PMID:25606414

  19. Variation in pharmacokinetics of omeprazole and its metabolites by gender and CYP2C19 genotype in Pakistani male and female subjects.

    PubMed

    Nazir, Shabnam; Iqbal, Zafar; Ahmad, Lateef; Ahmad, Sagheer

    2016-05-01

    Pharmacokinetics (PK) variation of drugs in males and females may affect therapeutic effectiveness and safety. In current study the PK differences for omeprazole and its metabolites5-hydroxy-omeprazole and omeprazole-sulphone were evaluated in males and females. The current study also considered PK comparison of Pakistani subjects using the CYP2C19 genotype as variable. A single oral dose (40mg omeprazole), open-labeland, non-controlled clinical trial was arranged. Samples were quantified using reversed phase HPLC-UV method. CYP2C19 genotype of subjects was determined by tetra primer polymerization chain reaction (PCR) assay. There was a significant increase in Cmax (from 2 to 2.9μg/ml, p=0.004**), (from 6.67 to 8.74μg-hr/ml, p=0.05*) and elimination half-life (from 1.05 to 2.1 hr, p=0.0001*) of omeprazole in females compared with males. Cmax and of 5-hydroxy-omeprazole (0.0248* and 0.0001***, respectively) and omeprazole-sulphone (0.0001*** and 0.001**, respectively) was significantly higher in females than males when compared at 95% confidence interval. The Cmax and AUC of omeprazole showed a significant raise (p=0.01* and 0.04*, respectively) in Homz PMs (Homozygous Poor Metabolizers) compared with Homz EMs (Homozygous Extensive Metabolizers) and Htrz PMs (Heterozygous Poor Metabolizers) while Cmax and AUC of 5-hydroxy-omeprazolewas significantly higher (p=0.01* and 0.04*, respectively) in Homz EMs compared with Homz PMs and HtrzPMs. AUC of omeprazole was significantly higher in females while its elimination also took longer compared with males. AUC of omeprazole was significantly higher in Homz PMs indicating that CYP2C19* displayed genetically deficient metabolism in its homozygous state. PMID:27166533

  20. Simulation with cells in vitro of tamoxifen treatment in premenopausal breast cancer patients with different CYP2D6 genotypes

    PubMed Central

    Maximov, Philipp Y; McDaniel, Russell E; Fernandes, Daphne J; Korostyshevskiy, Valeriy R; Bhatta, Puspanjali; Mürdter, Thomas E; Flockhart, David A; Jordan, V Craig

    2014-01-01

    Background and Purpose Tamoxifen is a prodrug that is metabolically activated by 4-hydroxylation to the potent primary metabolite 4-hydroxytamoxifen (4OHT) or via another primary metabolite N-desmethyltamoxifen (NDMTAM) to a biologically active secondary metabolite endoxifen through a cytochrome P450 2D6 variant system (CYP2D6). To elucidate the mechanism of action of tamoxifen and the importance of endoxifen for its effect, we determined the anti-oestrogenic efficacy of tamoxifen and its metabolites, including endoxifen, at concentrations corresponding to serum levels measured in breast cancer patients with various CYP2D6 genotypes (simulating tamoxifen treatment). Experimental Approach The biological effects of tamoxifen and its metabolites on cell growth and oestrogen-responsive gene modulation were evaluated in a panel of oestrogen receptor-positive breast cancer cell lines. Actual clinical levels of tamoxifen metabolites in breast cancer patients were used in vitro along with actual levels of oestrogens observed in premenopausal patients taking tamoxifen. Key Results Tamoxifen and its primary metabolites (4OHT and NDMTAM) only partially inhibited the stimulant effects of oestrogen on cells. The addition of endoxifen at concentrations corresponding to different CYP2D6 genotypes was found to enhance the anti-oestrogenic effect of tamoxifen and its metabolites with an efficacy that correlated with the concentration of endoxifen; at concentrations corresponding to the extensive metabolizer genotype it further inhibited the actions of oestrogen. In contrast, lower concentrations of endoxifen (intermediate and poor metabolizers) had little or no anti-oestrogenic effects. Conclusions and Implications Endoxifen may be a clinically relevant metabolite in premenopausal patients as it provides additional anti-oestrogenic actions during tamoxifen treatment. PMID:25073551

  1. 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

  2. Lack of association between peri-procedural myocardial damage and CYP2C19 gene variant in elective percutaneous coronary intervention.

    PubMed

    Yoshimura, Hiromi; Kaikita, Koichi; Ono, Takamichi; Iwashita, Satomi; Nakayama, Naoki; Sato, Koji; Horio, Eiji; Tsujita, Kenichi; Kojima, Sunao; Tayama, Shinji; Hokimoto, Seiji; Ogawa, Hisao

    2015-09-01

    Peri-procedural myocardial damage (MD) is associated with increased risk of major in-hospital complications and adverse clinical events. The aim of this study was to evaluate the effects of on-clopidogrel platelet aggregation and CYP2C19-reduced-function gene variants on elective percutaneous coronary intervention (PCI)-related MD. We measured changes in serum high-sensitive troponin T (hs-TnT) levels, CYP2C19 genotype, and on-clopidogrel platelet aggregation (PA) using VerifyNow(®) P2Y12 system in 91 patients who received stent implantation (stent group). The control group comprised 30 patients who did not receive PCI. Blood samples were obtained before and 24 h after PCI or coronary angiography (CAG). Patients of the stent group were divided into high and low MD groups based on the median value of hs-TnT level at 24 h after PCI. Serum hs-TnT levels were significantly higher 24 h after PCI (86.8 ± 121.5 pg/ml) compared with before PCI (9.4 ± 5.3, p < 0.001), whereas the levels were identical before and 24 h after CAG in the control group. Simple logistic regression analysis demonstrated that MD correlated with age (p = 0.014), estimated GFR (p = 0.003), hemoglobin A1c (p = 0.015), baseline serum hs-TnT (p = 0.049), and stent length (p < 0.001). Multiple logistic regression analysis identified old age, high hemoglobin A1c level, and long stent, but not CYP2C19 reduced-function allele or high on-clopidogrel PA, as independent predictors of elective PCI-related MD. The present study demonstrated no significant relation between peri-procedural MD and high on-clopidgrel PA associated with CYP2C19 reduced-function allele in patients undergoing elective PCI. PMID:24781308

  3. 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. PMID:26926096

  4. Cytochrome P450-2D6 extensive metabolizers are more vulnerable to methamphetamine-associated neurocognitive impairment: Preliminary findings

    PubMed Central

    CHERNER, MARIANA; BOUSMAN, CHAD; EVERALL, IAN; BARRON, DANIEL; LETENDRE, SCOTT; VAIDA, FLORIN; ATKINSON, J. HAMPTON; HEATON, ROBERT; GRANT, IGOR

    2012-01-01

    While neuropsychological deficits are evident among methamphetamine (meth) addicts, they are often unrelated to meth exposure parameters such as lifetime consumption and length of abstinence. The notion that some meth users develop neuropsychological impairments while others with similar drug exposure do not, suggests that there may be individual differences in vulnerability to the neurotoxic effects of meth. One source of differential vulnerability could come from genotypic variability in metabolic clearance of meth, dependent on the activity of cytochrome P450-2D6 (CYP2D6). We compared neuropsychological performance in 52 individuals with a history of meth dependence according with their CYP2D6 phenotype. All were free of HIV or hepatitis C infection and did not meet dependence criteria for other substances. Extensive metabolizers showed worse overall neuropsychological performance and were three times as likely to be cognitively impaired as intermediate/poor metabolizers. Groups did not differ in their demographic or meth use characteristics, nor did they evidence differences in mood disorder or other substance use. This preliminary study is the first to suggest that efficient meth metabolism is associated with worse neurocognitive outcomes in humans, and implicates the products of oxidative metabolism of meth as a possible source of brain injury. PMID:20727252

  5. Inhibition of Recombinant Cytochrome P450 Isoforms 2D6 and 2C9 by Diverse Drug-like Molecules

    PubMed Central

    McMasters, Daniel R.; Torres, Rhonda A.; Crathern, Susan J.; Dooney, Deborah L.; Nachbar, Robert B.; Sheridan, Robert P.; Korzekwa, Kenneth R.

    2008-01-01

    The affinities of a diverse set of 500 drug-like molecules to cytochrome P450 isoforms 2C9 and 2D6 were measured using recombinant expressed enzyme. The dose–response curve of each compound was fitted with a series of equations representing typical or various types of atypical kinetics. Atypical kinetics was identified where the Akaike Information Criterion, plus other criteria, suggested the kinetics was more complex than expected for a Michaelis–Menten model. Approximately 20% of the compounds were excluded due to poor solubility, and approximately 15% were excluded due to fluorescence interference. Of the remaining compounds, roughly half were observed to bind with an affinity of 200 μM or lower for each of the two isoforms. Atypical kinetics were observed in 18 percent of the compounds that bind to cytochrome 2C9 but less than 2 percent for 2D6. The resulting collection of competitive inhibitors and inactive compounds was analyzed for trends in binding affinity. For CYP2D6, a clear relationship between polar surface area and charge was observed, with the most potent inhibitors having a formal positive charge and a low percent polar surface area. For CYP2C9, no clear trend between activity and physicochemical properties could be seen for the group as a whole; however, certain classes of compounds have altered frequencies of activity and atypical kinetics. PMID:17559204

  6. Subcellular localization of rat CYP2E1 impacts metabolic efficiency toward common substrates.

    PubMed

    Hartman, Jessica H; Martin, H Cass; Caro, Andres A; Pearce, Amy R; Miller, Grover P

    2015-12-01

    Cytochrome P450 2E1 (CYP2E1) detoxifies or bioactivates many low molecular-weight compounds. Most knowledge about CYP2E1 activity relies on studies of the enzyme localized to endoplasmic reticulum (erCYP2E1); however, CYP2E1 undergoes transport to mitochondria (mtCYP2E1) and becomes metabolically active. We report the first comparison of in vitro steady-state kinetic profiles for erCYP2E1 and mtCYP2E1 oxidation of probe substrate 4-nitrophenol and pollutants styrene and aniline using subcellular fractions from rat liver. For all substrates, metabolic efficiency changed with substrate concentration for erCYP2E1 reflected in non-hyperbolic kinetic profiles but not for mtCYP2E1. Hyperbolic kinetic profiles for the mitochondrial enzyme were consistent with Michaelis-Menten mechanism in which metabolic efficiency was constant. By contrast, erCYP2E1 metabolism of 4-nitrophenol led to a loss of enzyme efficiency at high substrate concentrations when substrate inhibited the reaction. Similarly, aniline metabolism by erCYP2E1 demonstrated negative cooperativity as metabolic efficiency decreased with increasing substrate concentration. The opposite was observed for erCYP2E1 oxidation of styrene; the sigmoidal kinetic profile indicated increased efficiency at higher substrate concentrations. These mechanisms and CYP2E1 levels in mitochondria and endoplasmic reticulum were used to estimate the impact of CYP2E1 subcellular localization on metabolic flux of pollutants. Those models showed that erCYP2E1 mainly carries out aniline metabolism at all aniline concentrations. Conversely, mtCYP2E1 dominates styrene oxidation at low styrene concentrations and erCYP2E1 at higher concentrations. Taken together, subcellular localization of CYP2E1 results in distinctly different enzyme activities that could impact overall metabolic clearance and/or activation of substrates and thus impact the interpretation and prediction of toxicological outcomes. PMID:26463279

  7. [Induction of rat hepatic CYP2E1 expression by arecoline in vivo].

    PubMed

    Huang, Xiang-tao; Xiao, Run-mei; Wang, Ming-feng; Wang, Jun-jun; Chen, Yong

    2016-01-01

    The regulation mechanism of arecoline on rat hepatic CYP2E1 was studied in vivo. After oral administration of arecoline hydrobromide (AH; 4, 20 and 100 mg x kg(-1) x d(-1)) to rats for one week, the hepatic CYP2E1 mRNA level remained unchanged, but the hepatic CYP2E1 protein content was dose-dependently increased. Additionally, although the hepatic CYP2E1 activity was induced by AH treatment, the induction was attenuated with the increase in dosage. The results indicate that the effect of arecoline on rat hepaticdoes not involve transcriptional activation of the gene, but largely involves the stabilization of CYP2E1 protein against degradation or increased efficiency of CYP2E1 mRNA translation, and additionally involve the post- ranslational modification of CYP2E1 protein. Furthermore, the CYP2E1 response is fairly equal among the different species, the induction of rat hepatic CYP2E1 by arecoline suggests that there is a risk of metabolic interaction among the substrate drugs of CYP2E1 in betel-quid use human. PMID:27405178

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

    PubMed

    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

  9. 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

  10. 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. PMID:26122019

  11. 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

  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. 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

  14. Sex steroid hormones regulate constitutive expression of Cyp2e1 in female mouse liver

    PubMed Central

    Cheng, Jie; Gonzalez, Frank J.

    2013-01-01

    CYP2E1 is of paramount toxicological significance because it metabolically activates a large number of low-molecular-weight toxicants and carcinogens. In this context, factors that interfere with Cyp2e1 regulation may critically affect xenobiotic toxicity and carcinogenicity. The aim of this study was to investigate the role of female steroid hormones in the regulation of CYP2E1, as estrogens and progesterone are the bases of contraceptives and hormonal replacement therapy in menopausal women. Interestingly, a fluctuation in the hepatic expression pattern of Cyp2e1 was revealed in the different phases of the estrous cycle of female mice, with higher Cyp2e1 expression at estrus (E) and lower at methestrus (ME), highly correlated with that in plasma gonadal hormone levels. Depletion of sex steroids by ovariectomy repressed Cyp2e1 expression to levels similar to those detected in males and cyclic females at ME. Hormonal supplementation brought Cyp2e1 expression back to levels detected at E. The role of progesterone appeared to be more prominent than that of 17β-estradiol. Progesterone-induced Cyp2e1 upregulation could be attributed to inactivation of the insulin/PI3K/Akt/FOXO1 signaling pathway. Tamoxifen, an anti-estrogen, repressed Cyp2e1 expression potentially via activation of the PI3K/Akt/FOXO1 and GH/STAT5b-linked pathways. The sex steroid hormone-related changes in hepatic Cyp2e1 expression were highly correlated with those observed in Hnf-1α, β-catenin, and Srebp-1c. In conclusion, female steroid hormones are clearly involved in the regulation of CYP2E1, thus affecting the metabolism of a plethora of toxicants and carcinogenic agents, conditions that may trigger several pathologies or exacerbate the outcomes of various pathophysiological states. PMID:23548611

  15. Ubiquitin-dependent Proteasomal Degradation of Human Liver Cytochrome P450 2E1

    PubMed Central

    Wang, YongQiang; Guan, Shenheng; Acharya, Poulomi; Koop, Dennis R.; Liu, Yi; Liao, Mingxiang; Burlingame, Alma L.; Correia, Maria Almira

    2011-01-01

    Human liver CYP2E1 is a monotopic, endoplasmic reticulum-anchored cytochrome P450 responsible for the biotransformation of clinically relevant drugs, low molecular weight xenobiotics, carcinogens, and endogenous ketones. CYP2E1 substrate complexation converts it into a stable slow-turnover species degraded largely via autophagic lysosomal degradation. Substrate decomplexation/withdrawal results in a fast turnover CYP2E1 species, putatively generated through its futile oxidative cycling, that incurs endoplasmic reticulum-associated ubiquitin-dependent proteasomal degradation (UPD). CYP2E1 thus exhibits biphasic turnover in the mammalian liver. We now show upon heterologous expression of human CYP2E1 in Saccharomyces cerevisiae that its autophagic lysosomal degradation and UPD pathways are evolutionarily conserved, even though its potential for futile catalytic cycling is low due to its sluggish catalytic activity in yeast. This suggested that other factors (i.e. post-translational modifications or “degrons”) contribute to its UPD. Indeed, in cultured human hepatocytes, CYP2E1 is detectably ubiquitinated, and this is enhanced on its mechanism-based inactivation. Studies in Ubc7p and Ubc5p genetically deficient yeast strains versus corresponding isogenic wild types identified these ubiquitin-conjugating E2 enzymes as relevant to CYP2E1 UPD. Consistent with this, in vitro functional reconstitution analyses revealed that mammalian UBC7/gp78 and UbcH5a/CHIP E2-E3 ubiquitin ligases were capable of ubiquitinating CYP2E1, a process enhanced by protein kinase (PK) A and/or PKC inclusion. Inhibition of PKA or PKC blocked intracellular CYP2E1 ubiquitination and turnover. Here, through mass spectrometric analyses, we identify some CYP2E1 phosphorylation/ubiquitination sites in spatially associated clusters. We propose that these CYP2E1 phosphorylation clusters may serve to engage each E2-E3 ubiquitination complex in vitro and intracellularly. PMID:21209460

  16. A proposed mechanism for the adverse effects of acebutolol: CES2 and CYP2C19-mediated metabolism and antinuclear antibody production.

    PubMed

    Muta, Kyotaka; Fukami, Tatsuki; Nakajima, Miki

    2015-12-15

    Acebutolol, a β-adrenergic receptor-blocker, occasionally causes drug-induced lupus erythematosus (DILE). Acebutolol is mainly metabolized to diacetolol. Because metabolic activation has been considered to be related to acebutolol-induced toxicity, we sought to identify the enzymes that are responsible for acebutolol metabolism and investigate their involvement in acebutolol-induced toxicity. By using human liver microsomes (HLM) or intestinal microsomes and recombinant enzymes, we found that diacetolol was produced via hydrolysis by carboxylesterase 2 (CES2) and subsequent acetylation by N-acetyltransferase 2 (NAT2). When acetolol, a hydrolytic metabolite of acebutolol, was incubated with HLM and an NADPH-generating system, a metabolite conjugated with N-acetylcystein was generated. This metabolite was found to be formed by CYP2C19 based on studies with a panel of recombinant cytochrome P450 enzymes and an inhibition study using HLM with tranylcypromine, a CYP2C19 inhibitor. Because antinuclear antibody (ANA) production is associated with DILE, we investigated whether ANA was detected in plasma from mice treated with acebutolol. Administration of acebutolol (100mg/kg, p.o.) to female C57BL/6 mice for 30 days resulted in ANA production in plasma in seven of thirteen mice. The number of mice that showed ANA production was larger in mice co-treated with pregnenolone 16α-carbonitrile, an inducer of P450s, whereas it was lower in mice co-treated with tri-o-tolylphosphate or 1-aminobenzotriazole, which are inhibitors of esterases or P450s, respectively. These results suggested that the hydrolysis and oxidation of acebutolol was associated with ANA production. In summary, this study demonstrated that metabolic activation may be a causal factor of adverse reactions of acebutolol. PMID:26408002

  17. Modulation of CYP2D6 and CYP3A4 metabolic activities by Ferula asafetida resin

    PubMed Central

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

    2014-01-01

    Present study investigated the potential effects of Ferula asafetida resin on metabolic activities of human drug metabolizing enzymes: CYP2D6 and CYP3A4. Dextromethorphan (DEX) was used as a marker to assess metabolic activities of these enzymes, based on its CYP2D6 and CYP3A4 mediated metabolism to dextrorphan (DOR) and 3-methoxymorphinan (3-MM), respectively. In vitro study was conducted by incubating DEX with human liver microsomes and NADPH in the presence or absence of Asafetida alcoholic extract. For clinical study, healthy human volunteers received a single dose of DEX alone (phase-I) and repeated the same dose after a washout period and four-day Asafetida treatment (phase-II). Asafetida showed a concentration dependent inhibition on DOR formation (in vitro) and a 33% increase in DEX/DOR urinary metabolic ratio in clinical study. For CYP3A4, formation of 3-MM in microsomes was increased at low Asafetida concentrations (10, 25 and 50 μg/ml) but slightly inhibited at the concentration of 100 μg/ml. On the other hand, in vivo observations revealed that Asafetida significantly increased DEX/3-MM urinary metabolic ratio. The findings of this study suggest that Asafetida may have a significant effect on CYP3A4 metabolic activity. Therefore, using Ferula asafetida with CYP3A4 drug substrates should be cautioned especially those with narrow therapeutic index such as cyclosporine, tacrolimus and carbamazepine. PMID:25561870

  18. Single dose, CYP2D6 genotype-stratified pharmacokinetic study of atomoxetine in children with ADHD.

    PubMed

    Brown, J T; Abdel-Rahman, S M; van Haandel, L; Gaedigk, A; Lin, Y S; Leeder, J S

    2016-06-01

    The effect of CYP2D6 genotype on the dose-exposure relationship for atomoxetine has not been well characterized in children. Children 6-17 years of age diagnosed with attention-deficit hyperactivity disorder (ADHD) were stratified by CYP2D6 genotype into groups with 0 (poor metabolizers [PMs], n = 4), 0.5 (intermediate metabolizers [IMs], n = 3), one (extensive metabolizer [EM]1, n = 8) or two (EM2, n = 8) functional alleles and administered a single 0.5 mg/kg oral dose of atomoxetine (ATX). Plasma and urine samples were collected for 24 (IM, EM1, and EM2) or 72 hours (PMs). Dose-corrected ATX systemic exposure (area under the curve [AUC]0-∞ ) varied 29.6-fold across the study cohort, ranging from 4.4 ± 2.7 μM*h in EM2s to 5.8 ± 1.7 μM*h, 16.3 ± 2.9 μM*h, and 50.2 ± 7.3 μM*h in EM1s, IMs, and PMs, respectively (P < 0.0001). Simulated steady state profiles at the maximum US Food and Drug Administration (FDA)-recommended dose suggest that most patients are unlikely to attain adequate ATX exposures. These data support the need for individualized dosing strategies for more effective use of the medication. PMID:26660002

  19. Use of pharmacogenetics in bioequivalence studies to reduce sample size: an example with mirtazapine and CYP2D6.

    PubMed

    González-Vacarezza, N; Abad-Santos, F; Carcas-Sansuan, A; Dorado, P; Peñas-Lledó, E; Estévez-Carrizo, F; Llerena, A

    2013-10-01

    In bioequivalence studies, intra-individual variability (CV(w)) is critical in determining sample size. In particular, highly variable drugs may require enrollment of a greater number of subjects. We hypothesize that a strategy to reduce pharmacokinetic CV(w), and hence sample size and costs, would be to include subjects with decreased metabolic enzyme capacity for the drug under study. Therefore, two mirtazapine studies, two-way, two-period crossover design (n=68) were re-analysed to calculate the total CV(w) and the CV(w)s in three different CYP2D6 genotype groups (0, 1 and ≥ 2 active genes). The results showed that a 29.2 or 15.3% sample size reduction would have been possible if the recruitment had been of individuals carrying just 0 or 0 plus 1 CYP2D6 active genes, due to the lower CV(w). This suggests that there may be a role for pharmacogenetics in the design of bioequivalence studies to reduce sample size and costs, thus introducing a new paradigm for the biopharmaceutical evaluation of drug products. PMID:22733239

  20. Effects of monoamine oxidase inhibitor and cytochrome P450 2D6 status on 5-Methoxy-N,N-dimethyltryptamine Metabolism and Pharmacokinetics

    PubMed Central

    Shen, Hong-Wu; Wu, Chao; Jiang, Xi-Ling; Yu, Ai-Ming

    2010-01-01

    5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a natural psychoactive indolealkylamine drug that has been used for recreational purpose. Our previous study revealed that polymorphic cytochrome P450 2D6 (CYP2D6) catalyzed 5-MeO-DMT O-demethylation to produce active metabolite bufotenine, while 5-MeO-DMT is mainly inactivated through deamination pathway mediated by monoamine oxidase (MAO). This study, therefore, aimed to investigate the impact of CYP2D6 genotype/phenotype status and MAO inhibitor (MAOI) on 5-MeO-DMT metabolism and pharmacokinetics. Enzyme kinetic studies using recombinant CYP2D6 allelic isozymes showed that CYP2D6.2 and CYP2D6.10 exhibited 2.6- and 40-fold lower catalytic efficiency (Vmax/Km), respectively, in producing bufotenine from 5-MeO-DMT, compared with wild-type CYP2D6.1. When co-incubated with MAOI pargyline, 5-MeO-DMT O-demethylation in 10 human liver microsomes showed significantly strong correlation with bufuralol 1’-hydroxylase activities (R² = 0.98; p < 0.0001) and CYP2D6 contents (R² = 0.77; p = 0.0007), whereas no appreciable correlations with enzymatic activities of other P450 enzymes. Furthermore, concurrent MAOI harmaline sharply reduced 5-MeO-DMT depletion and increased bufotenine formation in human CYP2D6 extensive metabolizer hepatocytes. In vivo studies in wild-type and CYP2D6-humanized (Tg-CYP2D6) mouse models showed that Tg-CYP2D6 mice receiving the same dose of 5-MeO-DMT (20 mg/kg, i.p.) had 60% higher systemic exposure to metabolite bufotenine. In addition, pre-treatment of harmaline (5 mg/kg, i.p.) led to 3.6- and 4.4-fold higher systemic exposure to 5-MeO-DMT (2 mg/kg, i.p.), and 9.9- and 6.1-fold higher systemic exposure to bufotenine in Tg-CYP2D6 and wild-type mice, respectively. These findings indicate that MAOI largely affects 5-MeO-DMT metabolism and pharmacokinetics, as well as bufotenine formation that is mediated by CYP2D6. PMID:20206139

  1. Effects of monoamine oxidase inhibitor and cytochrome P450 2D6 status on 5-methoxy-N,N-dimethyltryptamine metabolism and pharmacokinetics.

    PubMed

    Shen, Hong-Wu; Wu, Chao; Jiang, Xi-Ling; Yu, Ai-Ming

    2010-07-01

    5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a natural psychoactive indolealkylamine drug that has been used for recreational purpose. Our previous study revealed that polymorphic cytochrome P450 2D6 (CYP2D6) catalyzed 5-MeO-DMT O-demethylation to produce active metabolite bufotenine, while 5-MeO-DMT is mainly inactivated through deamination pathway mediated by monoamine oxidase (MAO). This study, therefore, aimed to investigate the impact of CYP2D6 genotype/phenotype status and MAO inhibitor (MAOI) on 5-MeO-DMT metabolism and pharmacokinetics. Enzyme kinetic studies using recombinant CYP2D6 allelic isozymes showed that CYP2D6.2 and CYP2D6.10 exhibited 2.6- and 40-fold lower catalytic efficiency (V(max)/K(m)), respectively, in producing bufotenine from 5-MeO-DMT, compared with wild-type CYP2D6.1. When co-incubated with MAOI pargyline, 5-MeO-DMT O-demethylation in 10 human liver microsomes showed significantly strong correlation with bufuralol 1'-hydroxylase activities (R(2)=0.98; P<0.0001) and CYP2D6 contents (R(2)=0.77; P=0.0007), whereas no appreciable correlations with enzymatic activities of other P450 enzymes. Furthermore, concurrent MAOI harmaline sharply reduced 5-MeO-DMT depletion and increased bufotenine formation in human CYP2D6 extensive metabolizer hepatocytes. In vivo studies in wild-type and CYP2D6-humanized (Tg-CYP2D6) mouse models showed that Tg-CYP2D6 mice receiving the same dose of 5-MeO-DMT (20mg/kg, i.p.) had 60% higher systemic exposure to metabolite bufotenine. In addition, pretreatment of harmaline (5mg/kg, i.p.) led to 3.6- and 4.4-fold higher systemic exposure to 5-MeO-DMT (2mg/kg, i.p.), and 9.9- and 6.1-fold higher systemic exposure to bufotenine in Tg-CYP2D6 and wild-type mice, respectively. These findings indicate that MAOI largely affects 5-MeO-DMT metabolism and pharmacokinetics, as well as bufotenine formation that is mediated by CYP2D6. PMID:20206139

  2. Nr2e1 Deficiency Augments Palmitate-Induced Oxidative Stress in Beta Cells

    PubMed Central

    Shi, Xiaoli; Deng, Haohua; Dai, Zhe; Xu, Yancheng; Xiong, Xiaokan; Ma, Pei; Cheng, Jing

    2016-01-01

    Nuclear receptor subfamily 2 group E member 1 (Nr2e1) has been regarded as an essential regulator of the growth of neural stem cells. However, its function elsewhere is unknown. In the present study, we generated Nr2e1 knockdown MIN6 cells and studied whether Nr2e1 knockdown affected basal beta cell functions such as proliferation, cell death, and insulin secretion. We showed that knockdown of Nr2e1 in MIN6 cells resulted in increased sensitivity to lipotoxicity, decreased proliferation, a partial G0/G1 cell-cycle arrest, and higher rates of apoptosis. Moreover, Nr2e1 deficiency exaggerates palmitate-induced impairment in insulin secretion. At the molecular level, Nr2e1 deficiency augments palmitate-induced oxidative stress. Nr2e1 deficiency also resulted in decreases in antioxidant enzymes and expression level of Nrf2. Together, this study indicated a potential protective effect of Nr2e1 on beta cells, which may serve as a target for the development of novel therapies for diabetes. PMID:26649147

  3. Oxidative stress mediated toxicity exerted by ethanol-inducible CYP2E1

    SciTech Connect

    Wu Defeng; Cederbaum, Arthur I. . E-mail: arthur.cederbaum@mssm.edu

    2005-09-01

    Induction of CYP2E1 by ethanol is one of the central pathways by which ethanol generates a state of oxidative stress in hepatocytes. To study the biochemical and toxicological actions of CYP2E1, our laboratory established HepG2 cell lines which constitutively overexpress CYP2E1 and characterized these cells with respect to ethanol toxicity. Addition of ethanol or an unsaturated fatty acid such as arachidonic acid or iron was toxic to the CYP2E1-expressing cells but not control cells. This toxicity was associated with elevated lipid peroxidation and could be prevented by antioxidants and inhibitors of CYP2E1. Apoptosis occurred in the CYP2E1-expressing cells exposed to ethanol, arachidonic acid, or iron. Removal of GSH caused a loss of viability in the CYP2E1-expressing cells even in the absence of added toxin or pro-oxidant. This was associated with mitochondrial damage and decreased mitochondrial membrane potential. Low concentrations of iron and arachidonic acid synergistically interacted with CYP2E1 to produce cell toxicity, suggesting these nutrients may act as priming or sensitizing agents to alcohol-induced liver injury. Surprisingly, CYP2E1-expressing cells had elevated GSH levels, due to transcriptional activation of glutamate cysteine ligase. Similarly, levels of catalase, alpha-, and microsomal glutathione transferase were also increased, suggesting that upregulation of these antioxidant genes may reflect an adaptive mechanism to remove CYP2E1-derived oxidants. Using co-cultures, interaction between CYP2E1-derived diffusible mediators to activate collagen production in hepatic stellate cells was found. While it is likely that several mechanisms contribute to alcohol-induced liver injury, the linkage between CYP2E1-dependent oxidative stress, mitochondrial injury, stellate cell activation, and GSH homeostasis may contribute to the toxic action of ethanol on the liver. HepG2 cell lines overexpressing CYP2E1 may be a valuable model to characterize the

  4. 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

  5. Genetic polymorphisms and drug interactions modulating CYP2D6 and CYP3A activities have a major effect on oxycodone analgesic efficacy and safety

    PubMed Central

    Samer, CF; Daali, Y; Wagner, M; Hopfgartner, G; Eap, CB; Rebsamen, MC; Rossier, MF; Hochstrasser, D; Dayer, P; Desmeules, JA

    2010-01-01

    Background and purpose: The major drug-metabolizing enzymes for the oxidation of oxycodone are CYP2D6 and CYP3A. A high interindividual variability in the activity of these enzymes because of genetic polymorphisms and/or drug–drug interactions is well established. The possible role of an active metabolite in the pharmacodynamics of oxycodone has been questioned and the importance of CYP3A-mediated effects on the pharmacokinetics and pharmacodynamics of oxycodone has been poorly explored. Experimental approach: We conducted a randomized crossover (five arms) double-blind placebo-controlled study in 10 healthy volunteers genotyped for CYP2D6. Oral oxycodone (0.2 mg·kg−1) was given alone or after inhibition of CYP2D6 (with quinidine) and/or of CYP3A (with ketoconazole). Experimental pain (cold pressor test, electrical stimulation, thermode), pupil size, psychomotor effects and toxicity were assessed. Key results: CYP2D6 activity was correlated with oxycodone experimental pain assessment. CYP2D6 ultra-rapid metabolizers experienced increased pharmacodynamic effects, whereas cold pressor test and pupil size were unchanged in CYP2D6 poor metabolizers, relative to extensive metabolizers. CYP2D6 blockade reduced subjective pain threshold (SPT) for oxycodone by 30% and the response was similar to placebo. CYP3A4 blockade had a major effect on all pharmacodynamic assessments and SPT increased by 15%. Oxymorphone Cmax was correlated with SPT assessment (ρS= 0.7) and the only independent positive predictor of SPT. Side-effects were observed after CYP3A4 blockade and/or in CYP2D6 ultra-rapid metabolizers. Conclusions and implications: The modulation of CYP2D6 and CYP3A activities had clear effects on oxycodone pharmacodynamics and these effects were dependent on CYP2D6 genetic polymorphism. PMID:20590588

  6. The frequency of cytochrome P450 2E1 polymorphisms in Black South Africans.

    PubMed

    Chelule, Paul K; Pegoraro, Rosemary J; Gqaleni, Nceba; Dutton, Michael F

    2006-01-01

    Polymorphisms in the promoter region of the Cytochrome P4502E1 (CYP2E1) gene reportedly modify the metabolic activity of CYP2E1 enzyme, and have been associated with increased susceptibility to squamous cell carcinoma (SCC) of the oesophagus in high prevalence areas such as China. To assess the frequency of these polymorphisms in Black South Africans, a population with a high incidence of oesophageal SCC, this study examined genomic DNA from 331 subjects for restriction fragment length polymorphisms in the CYP2E1 (RsaI and PstI digestion). The frequency of the CYP2E1 c1/c1 and c1/c3 genotypes was 95% and 5% respectively. The frequency of the CYP2E1 allele distribution was found to be markedly different between Chinese and South African populations; hence it is important to place racial differences into consideration when proposing allelic variants as genetic markers for cancer. PMID:17264406

  7. Role of CYP2E1 in thioacetamide-induced mouse hepatotoxicity

    SciTech Connect

    Kang, Jin Seok; Wanibuchi, Hideki; Morimura, Keiichirou; Wongpoomchai, Rawiwan; Chusiri, Yaowares; Gonzalez, Frank J.; Fukushima, Shoji

    2008-05-01

    Previous experiments showed that treatment of mice and rats with thioacetamide (TAA) induced liver cell damage, fibrosis and/or cirrhosis, associated with increased oxidative stress and activation of hepatic stellate cells. Some experiments suggest that CYP2E1 may be involved in the metabolic activation of TAA. However, there is no direct evidence on the role of CYP2E1 in TAA-mediated hepatotoxicity. To clarify this, TAA-induced hepatotoxicity was investigated using Cyp2e1-null mice. Male wild-type and Cyp2e1-null mice were treated with TAA (200 mg/kg of body weight, single, i.p.) at 6 weeks of age, and hepatotoxicity examined 24 and 48 h after TAA treatment. Relative liver weights of Cyp2e1-null mice were significantly different at 24 h compared to wild-type mice (p < 0.01). Serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) in Cyp2e1-null mice were significantly different at both time points compared to wild-type mice (p < 0.01). Histopathological examination showed Cyp2e1-null mice represented no hepatototoxic lesions, in clear contrast to severe centriobular necrosis, inflammation and hemorrhage at both time points in wild-type mice. Marked lipid peroxidation was also only limited to wild-type mice (p < 0.01). Similarly, TNF-{alpha}, IL-6 and glutathione peroxidase mRNA expression in Cyp2e1-null mice did not significantly differ from the control levels, contrasting with the marked alteration in wild-type mice (p < 0.01). Western blot analysis further revealed no increase in iNOS expression in Cyp2e1-null mice. These results reveal that CYP2E1 mediates TAA-induced hepatotoxicity in wild-type mice as a result of increased oxidative stress.

  8. Molecular mechanism of trichloroethylene-induced hepatotoxicity mediated by CYP2E1

    SciTech Connect

    Ramdhan, Doni Hikmat; Kamijima, Michihiro; Yamada, Naoyasu; Ito, Yuki; Yanagiba, Yukie; Nakamura, Daichi; Okamura, Ai; Ichihara, Gaku; Aoyama, Toshifumi; Gonzalez, Frank J.; Nakajima, Tamie

    2008-09-15

    Cytochrome P450 (CYP) 2E1 was suggested to be the major enzyme involved in trichloroethylene (TRI) metabolism and TRI-induced hepatotoxicity, although the latter molecular mechanism is not fully understood. The involvement of CYP2E1 in TRI-induced hepatotoxicity and its underlying molecular mechanism were studied by comparing hepatotoxicity in cyp2e1{sup +/+} and cyp2e1{sup -/-} mice. The mice were exposed by inhalation to 0 (control), 1000, or 2000 ppm of TRI for 8 h a day, for 7 days, and TRI-hepatotoxicity was assessed by measuring plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities and histopathology. Urinary metabolites of trichloroethanol and trichloroacetic acid (TCA) were considerably greater in cyp2e1{sup +/+} compared to cyp2e1{sup -/-} mice, suggesting that CYP2E1 is the major P450 involved in the formation of these metabolites. Consistent with elevated plasma ALT and AST activities, cyp2e1{sup +/+} mice in the 2000 ppm group showed histopathological inflammation. TRI significantly upregulated PPAR{alpha}, which might function to inhibit NF{kappa}B p50 and p65 signalling. In addition, TRI-induced NF{kappa}B p52 mRNA, and significantly positive correlation between NF{kappa}B p52 mRNA expression and plasma ALT activity levels were observed, suggesting the involvement of p52 in liver inflammation. Taken together, the current study directly demonstrates that CYP2E1 was the major P450 involved in the first step of the TRI metabolism, and the metabolites produced may have two opposing roles: one inducing hepatotoxicity and the other protecting against the toxicity. Intermediate metabolite(s) from TRI to chloral hydrate produced by CYP2E1-mediated oxidation may be involved in the former, and TCA in the latter.

  9. Cytochrome P450 2E1 (CYP2E1) regulates the response to oxidative stress and migration of breast cancer cells

    PubMed Central

    2013-01-01

    Introduction The cytochrome P450 (CYP) enzymes are a class of heme-containing enzymes involved in phase I metabolism of a large number of xenobiotics. The CYP family member CYP2E1 metabolises many xenobiotics and pro-carcinogens, it is not just expressed in the liver but also in many other tissues such as the kidney, the lung, the brain, the gastrointestinal tract and the breast tissue. It is induced in several pathological conditions including cancer, obesity, and type II diabetes implying that this enzyme is implicated in other biological processes beyond its role in phase I metabolism. Despite the detailed description of the role of CYP2E1 in the liver, its functions in other tissues have not been extensively studied. In this study, we investigated the functional significance of CYP2E1 in breast carcinogenesis. Methods Cellular levels of reactive oxygen species (ROS) were measured by H2DCFDA (2 2.9.2 2′,7′-dichlorodihydrofluorescein diacetate) staining and autophagy was assessed by tracing the cellular levels of autophagy markers using western blot assays. The endoplasmic reticulum stress and the unfolded protein response (UPR) were detected by luciferase assays reflecting the splicing of mRNA encoding the X-box binding protein 1 (XBP1) transcription factor and cell migration was evaluated using the scratch wound assay. Gene expression was recorded with standard transcription assays including luciferase reporter and chromatin immunoprecipitation. Results Ectopic expression of CYP2E1 induced ROS generation, affected autophagy, stimulated endoplasmic reticulum stress and inhibited migration in breast cancer cells with different metastatic potential and p53 status. Furthermore, evidence is presented indicating that CYP2E1 gene expression is under the transcriptional control of the p53 tumor suppressor. Conclusions These results support the notion that CYP2E1 exerts an important role in mammary carcinogenesis, provide a potential link between ethanol metabolism

  10. Evidence for a tissue-specific induction of cutaneous CYP2E1 by dexamethasone.

    PubMed

    Sampol, E; Mirrione, A; Villard, P H; Piccerelle, P; Scoma, H; Berbis, P; Barra, Y; Durand, A; Lacarelle, B

    1997-06-27

    We studied in mouse the effect of topical application of dexamethasone or salicylic acid, on CYP2E1 and CYP3A expression (proteins and/or mRNA) in liver and skin. Dexamethasone was also administered by intraperitoneal injection. Topical application or intraperitoneal injection of dexamethasone increased cutaneous CYP2E1 (8 and 4-fold respectively) whereas the hepatic level of this isoform showed a slight decrease and hepatic CYP3A expression was increased (3-fold). Cutaneous CYP2E1 was increased (3-fold) after topical treatment by salicylic acid. This compound had no effect on hepatic CYP3A and CYP2E1 expression. Cutaneous CYP3A (protein and mRNA) was not detectable in all groups (control or treated animals). Dexamethasone and salicylic acid increased cutaneous CYP2E1 mRNA level (2.5 and 1.4-fold respectively). In conclusion, dexamethasone and salicylic acid induced cutaneous CYP2E1 protein and mRNA level. Cutaneous CYP2E1 induction by dexamethasone is a tissue-specific process. PMID:9207195

  11. 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.

  12. 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

  13. Clinical assessment of CYP2D6-mediated herb-drug interactions in humans: effects of milk thistle, black cohosh, goldenseal, kava kava, St. John's wort, and Echinacea.

    PubMed

    Gurley, Bill J; Swain, Ashley; Hubbard, Martha A; Williams, D Keith; Barone, Gary; Hartsfield, Faith; Tong, Yudong; Carrier, Danielle J; Cheboyina, Shreekar; Battu, Sunil K

    2008-07-01

    Cytochrome P450 2D6 (CYP2D6), an important CYP isoform with regard to drug-drug interactions, accounts for the metabolism of approximately 30% of all medications. To date, few studies have assessed the effects of botanical supplementation on human CYP2D6 activity in vivo. Six botanical extracts were evaluated in three separate studies (two extracts per study), each incorporating 16 healthy volunteers (eight females). Subjects were randomized to receive a standardized botanical extract for 14 days on separate occasions. A 30-day washout period was interposed between each supplementation phase. In study 1, subjects received milk thistle (Silybum marianum) and black cohosh (Cimicifuga racemosa). In study 2, kava kava (Piper methysticum) and goldenseal (Hydrastis canadensis) extracts were administered, and in study 3 subjects received St. John's wort (Hypericum perforatum) and Echinacea (Echinacea purpurea). The CYP2D6 substrate, debrisoquine (5 mg), was administered before and at the end of supplementation. Pre- and post-supplementation phenotypic trait measurements were determined for CYP2D6 using 8-h debrisoquine urinary recovery ratios (DURR). Comparisons of pre- and post-supplementation DURR revealed significant inhibition (approximately 50%) of CYP2D6 activity for goldenseal, but not for the other extracts. Accordingly, adverse herb-drug interactions may result with concomitant ingestion of goldenseal supplements and drugs that are CYP2D6 substrates. PMID:18214849

  14. Selective Time- and NADPH-Dependent Inhibition of Human CYP2E1 by Clomethiazole.

    PubMed

    Stresser, David M; Perloff, Elke S; Mason, Andrew K; Blanchard, Andrew P; Dehal, Shangara S; Creegan, Timothy P; Singh, Ritu; Gangl, Eric T

    2016-08-01

    The sedative clomethiazole (CMZ) has been used in Europe since the mid-1960s to treat insomnia and alcoholism. It has been previously demonstrated in clinical studies to reversibly inhibit human CYP2E1 in vitro and decrease CYP2E1-mediated elimination of chlorzoxazone. We have investigated the selectivity of CMZ inhibition of CYP2E1 in pooled human liver microsomes (HLMs). In a reversible inhibition assay of the major drug-metabolizing cytochrome P450 (P450) isoforms, CYP2A6 and CYP2E1 exhibited IC50 values of 24 µM and 42 µM, respectively with all other isoforms exhibiting values >300 µM. When CMZ was preincubated with NADPH and liver microsomal protein for 30 minutes before being combined with probe substrates, however, more potent inhibition was observed for CYP2E1 and CYP2B6 but not CYP2A6 or other P450 isoforms. The substantial increase in potency of CYP2E1 inhibition upon preincubation enables the use of CMZ to investigate the role of human CYP2E1 in xenobiotic metabolism and provides advantages over other chemical inhibitors of CYP2E1. The KI and kinact values obtained with HLM-catalyzed 6-hydroxylation of chlorzoxazone were 40 µM and 0.35 minute(-1), respectively, and similar to values obtained with recombinant CYP2E1 (41 µM, 0.32 minute(-1)). The KI and kinact values, along with other parameters, were used in a mechanistic static model to explain earlier observations of a profound decrease in the rate of chlorzoxazone elimination in volunteers despite the absence of detectable CMZ in blood. PMID:27149898

  15. Involvement of CYP 2E1 enzyme in ovotoxicity caused by 4-vinylcyclohexene and its metabolites.

    PubMed

    Rajapaksa, Kathila S; Cannady, Ellen A; Sipes, I Glenn; Hoyer, Patricia B

    2007-06-01

    4-Vinylcyclohexene (VCH) is bioactivated by hepatic CYP 2A and 2B to a monoepoxide (VCM) and subsequently to an ovotoxic diepoxide metabolite (VCD). Studies suggest that the ovary can directly bioactivate VCH via CYP 2E1. The current study was designed to evaluate the role of ovarian CYP 2E1 in VCM-induced ovotoxicity. Postnatal day 4 B6C3F(1) and CYP 2E1 wild-type (+/+) and null (-/-) mouse ovaries were cultured (15 days) with VCD (30 microM), 1,2-VCM (125-1000 microM), or vehicle. Twenty-eight days female CYP 2E1 +/+ and -/- mice were dosed daily (15 days; ip) with VCH, 1,2-VCM, VCD or vehicle. Following culture or in vivo dosing, ovaries were histologically evaluated. In culture, VCD decreased (p<0.05) primordial and primary follicles in ovaries from all three groups of mice. 1,2-VCM decreased (p<0.05) primordial follicles in B6C3F(1) and CYP 2E1 +/+ ovaries, but not in CYP 2E1 -/- ovaries in culture. 1,2-VCM did not affect primary follicles in any group of mouse ovaries. Conversely, following in vivo dosing, primordial and primary follicles were reduced (p<0.05) by VCD and VCM in CYP2E1 +/+ and -/-, and by VCH in +/+ mice. The data demonstrate that, whereas in vitro ovarian bioactivation of VCM requires CYP 2E1 enzyme, in vivo CYP 2E1 plays a minimal role. Thus, the findings support that hepatic metabolism dominates the contribution made by the ovary in bioactivation of VCM to its ovotoxic metabolite, VCD. This study also demonstrates the use of a novel ovarian culture system to evaluate ovary-specific metabolism of xenobiotics. PMID:17462685

  16. Involvement of CYP 2E1 enzyme in ovotoxicity caused by 4-vinylcyclohexene and its metabolites

    SciTech Connect

    Rajapaksa, Kathila S.; Cannady, Ellen A.; Sipes, I. Glenn; Hoyer, Patricia B. . E-mail: hoyer@u.arizona.edu

    2007-06-01

    4-Vinylcyclohexene (VCH) is bioactivated by hepatic CYP 2A and 2B to a monoepoxide (VCM) and subsequently to an ovotoxic diepoxide metabolite (VCD). Studies suggest that the ovary can directly bioactivate VCH via CYP 2E1. The current study was designed to evaluate the role of ovarian CYP 2E1 in VCM-induced ovotoxicity. Postnatal day 4 B6C3F{sub 1} and CYP 2E1 wild-type (+/+) and null (-/-) mouse ovaries were cultured (15 days) with VCD (30 {mu}M), 1,2-VCM (125-1000 {mu}M), or vehicle. Twenty-eight days female CYP 2E1 +/+ and -/- mice were dosed daily (15 days; ip) with VCH, 1,2-VCM, VCD or vehicle. Following culture or in vivo dosing, ovaries were histologically evaluated. In culture, VCD decreased (p < 0.05) primordial and primary follicles in ovaries from all three groups of mice. 1,2-VCM decreased (p < 0.05) primordial follicles in B6C3F{sub 1} and CYP 2E1 +/+ ovaries, but not in CYP 2E1 -/- ovaries in culture. 1,2-VCM did not affect primary follicles in any group of mouse ovaries. Conversely, following in vivo dosing, primordial and primary follicles were reduced (p < 0.05) by VCD and VCM in CYP2E1 +/+ and -/-, and by VCH in +/+ mice. The data demonstrate that, whereas in vitro ovarian bioactivation of VCM requires CYP 2E1 enzyme, in vivo CYP 2E1 plays a minimal role. Thus, the findings support that hepatic metabolism dominates the contribution made by the ovary in bioactivation of VCM to its ovotoxic metabolite, VCD. This study also demonstrates the use of a novel ovarian culture system to evaluate ovary-specific metabolism of xenobiotics.

  17. Effects of cigarette smoking and cytochrome P450 2D6 genotype on fluvoxamine concentration in plasma of Japanese patients.

    PubMed

    Katoh, Yasuhiro; Uchida, Shinya; Kawai, Masayoshi; Takei, Noriyoshi; Mori, Norio; Kawakami, Junichi; Kagawa, Yoshiyuki; Yamada, Shizuo; Namiki, Noriyuki; Hashimoto, Hisakuni

    2010-01-01

    Fluvoxamine is a selective serotonin reuptake inhibitor widely used in the treatment of depression and other psychiatric diseases. The aim of this study was to assess the clinical impact of cigarette smoking on plasma fluvoxamine concentration in Japanese patients, and evaluate whether the cytochrome P450 (CYP) 1A2 and CYP2D6 genotypes have effects on that concentration. Thirty-two Japanese patients receiving fluvoxamine were enrolled. They were maintained on the same daily dose of fluvoxamine (mean + or - S.D., 109.4 + or - 66.2 mg/d) for at least 4 weeks to obtain the steady-state plasma concentration. The steady-state plasma concentration-to-dose (C/D) ratio of fluvoxamine in patients who smoked (n = 6, 11.8 + or - 6.5 ng/ml/dose) was significantly lower than that in non-smoker patients (n = 26, 22.8 + or - 11.2 ng/ml/dose). There was no significant difference for the C/D ratio of fluvoxamine in patients with CYP1A2 -3860G/G, -3860G/A, and -3860A/A between non-smokers and smokers. Among non-smoker patients, the C/D ratios of fluvoxamine in those with one and two mutated alleles of CYP2D6 were 1.6- and 1.4-fold higher, respectively, than those with no mutated alleles, though the differences among those three genotype groups were not significant. Furthermore, stepwise multiple regression analysis revealed that cigarette smoking and daily dose had significant positive correlations with the plasma concentration of fluvoxamine. Our findings suggest that cigarette smoking has a significant impact on the steady-state plasma concentration of fluvoxamine in Japanese patients. PMID:20118554

  18. Pharmacokinetic interaction of flecainide and paroxetine in relation to the CYP2D6*10 allele in healthy Korean subjects

    PubMed Central

    Lim, Kyoung Soo; Cho, Joo-Youn; Jang, In-Jin; Kim, Bo-Hyung; Kim, JaeWoo; Jeon, Ji-Young; Tae, Yu-Mi; Yi, SoJeong; Eum, SoYoung; Shin, Sang-Goo; Yu, Kyung-Sang

    2008-01-01

    WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT The only existing study of CYP2D6*10-associated alterations in flecainide pharmacokinetics was retrospective. Paroxetine has been known as a strong inhibitor of CYP2D6. WHAT THIS STUDY ADDS This study reports that the extent of drug interaction between flecainide and paroxetine is influenced by the CYP2D6*10 allele in healthy subjects, which is frequent in Asians. AIMS The objectives were to evaluate the effect of CYP2D6 genetic polymorphism on the pharmacokinetics of flecainide, and also on the extent of drug interaction with paroxetine as a CYP2D6 inhibitor after a single oral administration in healthy subjects. METHODS An open-label, two-period, single-sequence, cross-over study was performed in 21 healthy Korean male volunteers (seven for CYP2D6*1/*1 or *1/*2, group 1; seven for CYP2D6*1/*10, group 2; seven for CYP2D6*10/*10 or *10/*36, group 3). Subjects were administered 200 mg of flecainide on day 1. After a 7-day wash-out period, subjects were administered 20 mg of paroxetine from day 8 to 14, and 200 mg of flecainide on day 15. Blood sampling was performed up to 72 h after flecainide administration. RESULTS Terminal elimination half-life and mean residence time (MRT) were significantly different among three genotype groups after a single oral administration of flecainide (P = 0.021, 0.011, respectively). Area under the concentration–time curve, terminal elimination half-life and MRT increased significantly after paroxetine co-administration only in groups 1 and 2. CONCLUSIONS This study reports that the extent of drug interaction between flecainide and paroxetine is influenced by the CYP2D6*10 allele in healthy subjects, which is frequent in Asians. PMID:18754843

  19. 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

  20. ATF4 deficiency protects hepatocytes from oxidative stress via inhibiting CYP2E1 expression

    PubMed Central

    Wang, Chunxia; Li, Houkai; Meng, Qingshu; Du, Ying; Xiao, Fei; Zhang, Qian; Yu, Junjie; Li, Kai; Chen, Shanghai; Huang, Zhiying; Liu, Bin; Guo, Feifan

    2014-01-01

    Activating transcription factor (ATF) 4 is involved in the regulation of oxidative stress in fibroblasts and neurons. The role of ATF4 in hepatocytes, however, is unknown. The aim of this study was to investigate the role of ATF4 in hepatocytes in oxidative stress under a high-fat diet (HFD). Here, we showed that palmitate-stimulated reactive oxygen species (ROS) production and triglyceride (TG) accumulation is blocked by ATF4 deficiency in primary hepatocytes. Consistently, HFD-induced oxidative stress, TG accumulation and expression of cytochrome P450, family 2, subfamily, polypeptide 1 (CYP2E1) are also blocked by knocking down ATF4 expression in the mouse liver. This suggests that ATF4 might regulate oxidative stress viaCYP2E1 under an HFD. In addition, we observed that expression of CYP2E1 is indirectly regulated by ATF4 in a cAMP-responsive element binding protein (CREB)-dependent manner, which can directly activate the CYP2E1 promoter activity. Notably, ATF4-stimulated ROS production is inhibited in vivo by treatment with diallyl sulphide, a selective CYP2E1 inhibitor. Finally, we showed that ATF4 expression in the liver is responsible for the protective effects against HFD-induced CYP2E1 expression, oxidative stress, and TG accumulation. Taken together, these observations suggest that ATF4 is a novel regulator of oxidative stress as well as accumulation of TG in response to HFD. PMID:24373582

  1. 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

  2. Reduced CYP2D6 function is associated with gefitinib-induced rash in patients with non-small cell lung cancer

    PubMed Central

    2012-01-01

    Background Rash, liver dysfunction, and diarrhea are known major adverse events associated with erlotinib and gefitinib. However, clinical trials with gefitinib have reported different proportions of adverse events compared to trials with erlotinib. In an in vitro study, cytochrome P450 (CYP) 2D6 was shown to be involved in the metabolism of gefitinib but not erlotinib. It has been hypothesized that CYP2D6 phenotypes may be implicated in different adverse events associated with gefitinib and erlotinib therapies. Methods The frequency of each adverse event was evaluated during the period in which the patients received gefitinib or erlotinib therapy. CYP2D6 phenotypes were determined by analysis of CYP2D6 genotypes using real-time polymerase chain reaction techniques, which can detect single-nucleotide polymorphisms. The CYP2D6 phenotypes were categorized into 2 groups according to functional or reduced metabolic levels. In addition, we evaluated the odds ratio (OR) of the adverse events associated with each factor, including CYP2D6 activities and treatment types. Results A total of 232 patients received gefitinib therapy, and 86 received erlotinib therapy. Reduced function of CYP2D6 was associated with an increased risk of rash of grade 2 or more (OR, 0.44; 95% confidence interval [CI], 0.21–0.94; *p = 0.03), but not diarrhea ≥ grade 2 (OR, 0.49; 95% CI, 0.17–1.51; *p = 0.20) or liver dysfunction ≥ grade 2 (OR, 1.08; 95% CI, 0.52–2.34; *p = 0.84) in the gefitinib cohort. No associations were observed between any adverse events in the erlotinib cohort and CYP2D6 phenotypes (rash: OR, 1.77; 95% CI, 0.54–6.41; *p = 0.35/diarrhea: OR, 1.08; 95% CI, 0.21–7.43; *p = 0.93/liver dysfunction: OR, 0.93; 95% CI, 0.20–5.07; *p = 0.93). Conclusions The frequency of rash was significantly higher in patients with reduced CYP2D6 activity who treated with gefitinib compared to patients with functional CYP2D6. CYP2D6 phenotypes are a risk factor for the development of

  3. Complex Disease–, Gene–, and Drug–Drug Interactions: Impacts of Renal Function, CYP2D6 Phenotype, and OCT2 Activity on Veliparib Pharmacokinetics

    PubMed Central

    Li, Jing; Kim, Seongho; Sha, Xianyi; Wiegand, Richard; Wu, Jianmei; LoRusso, Patricia

    2014-01-01

    Purpose Veliparib, a poly (ADP-ribose) polymerase (PARP) inhibitor, undergoes renal excretion and liver metabolism. This study quantitatively assessed the interactions of veliparib with metabolizing enzyme (CYP2D6) and transporter (OCT2) in disease settings (renal impairment). Experimental Design Veliparib in vitro metabolism was examined in human liver microsomes and recombinant enzymes carrying wild-type CYP2D6 or functional defect variants (CYP2D6*10 and *4). Plasma pharmacokinetics were evaluated in 27 patients with cancer. A parent–metabolite joint population model was developed to characterize veliparib and metabolite (M8) pharmacokinetics and to identify patient factors influencing veliparib disposition. A physiologically based pharmacokinetic model integrated with a mechanistic kidney module was developed to quantitatively predict the individual and combined effects of renal function, CYP2D6 phenotype, and OCT2 activity on veliparib pharmacokinetics. Results In vitro intrinsic clearance of CYP2D6.1 and CYP2D6.10 for veliparib metabolism were 0.055 and 0.017 μL/min/pmol CYP, respectively. Population mean values for veliparib oral clearance and M8 clearance were 13.3 and 8.6 L/h, respectively. Creatinine clearance was identified as the significant covariate on veliparib oral clearance. Moderate renal impairment, CYP2D6 poor metabolizer, and co-administration of OCT2 inhibitor (cimetidine) increased veliparib steady-state exposure by 80%, 20%, and 30%, respectively. These factors collectively led to >2-fold increase in veliparib exposure. Conclusions Renal function (creatinine clearance) is a significant predictor for veliparib exposure in patients with cancer. Although a single factor (i.e., renal impairment, CYP2D6 deficiency, and reduced OCT2 activity) shows a moderate impact, they collectively could result in a significant and potentially clinically relevant increase in veliparib exposure. PMID:24947923

  4. Physiologically Based Pharmacokinetic Modeling of Tamoxifen and its Metabolites in Women of Different CYP2D6 Phenotypes Provides New Insight into the Tamoxifen Mass Balance

    PubMed Central

    Dickschen, Kristin; Willmann, Stefan; Thelen, Kirstin; Lippert, Jörg; Hempel, Georg; Eissing, Thomas

    2012-01-01

    Tamoxifen is a first-line endocrine agent in the mechanism-based treatment of estrogen receptor positive (ER+) mammary carcinoma and applied to breast cancer patients all over the world. Endoxifen is a secondary and highly active metabolite of tamoxifen that is formed among others by the polymorphic cytochrome P450 2D6 (CYP2D6). It is widely accepted that CYP2D6 poor metabolizers exert a pronounced decrease in endoxifen steady-state plasma concentrations compared to CYP2D6 extensive metabolizers. Nevertheless, an in-depth understanding of the chain of cause and effect between CYP2D6 genotype, endoxifen steady-state plasma concentration, and subsequent tamoxifen treatment benefit still remains to be evolved. In this study, physiologically based pharmacokinetic (PBPK)-modeling was applied to mechanistically investigate the impact of CYP2D6 phenotype on endoxifen formation in female breast cancer patients undergoing tamoxifen therapy. A PBPK-model of tamoxifen and its pharmacologically important metabolites N-desmethyltamoxifen (NDM-TAM), 4-hydroxytamoxifen (4-OH-TAM), and endoxifen was developed and validated. This model is able to simulate the pharmacokinetics (PK) after single and repeated oral tamoxifen doses in female breast cancer patients in dependence of the CYP2D6 phenotype. A detailed model-based analysis of the mass balance offered support for a recent hypothesis stating a more prominent role for endoxifen formation from 4-OH-TAM. In the future this model provides a good basis to further investigate the linkage of PK, mode of action, and treatment outcome in dependence of factors such as phenotype, ethnicity, or co-treatment with CYP2D6 inhibitors. PMID:22661948

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

    PubMed

    Yoshida, K; Sun, B; Zhang, L; Zhao, P; Abernethy, D R; Nolin, T D; Rostami-Hodjegan, A; Zineh, I; Huang, S-M

    2016-07-01

    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

  6. Diabetes mellitus increases the in vivo activity of cytochrome P450 2E1 in humans

    PubMed Central

    Wang, Zaiqi; Hall, Stephen D; Maya, Juan F; Li, Lang; Asghar, Ali; Gorski, J C

    2003-01-01

    Aim Cytochrome P450 2E1 (CYP2E1) is thought to activate a number of protoxins, and has been implicated in the development of liver disease. Increased hepatic expression of CYP2E1 occurs in rat models of diabetes but it is unclear whether human diabetics display a similar up-regulation. This study was designed to test the hypothesis that human diabetics experience enhanced CYP2E1 expression. Methods The pharmacokinetics of a single dose of chlorzoxazone (500 mg), used as an index of hepatic CYP2E1 activity, was determined in healthy subjects (n = 10), volunteers with Type I (n = 13), and Type II (n = 8) diabetes mellitus. Chlorzoxazone and 6-hydroxychlorzoxazone in serum and urine were analysed by high-performance liquid chromatography. The expression of CYP2E1 mRNA in peripheral blood mononuclear cells was quantified by reverse transcriptase-polymerase chain reaction. Results The mean ± s.d. (90% confidence interval of the difference) chlorzoxazone area under the plasma concentration-time curve was significantly (P ≤ 0.05) reduced in obese Type II diabetics (15.7 ± 11.3 µg h ml−1; 9, 22) compared with healthy subjects (43.5 ± 16.9 µg h ml−1; 16, 40) and Type I diabetics (32.8 ± 9.2 µg h ml−1; 9, 25). There was a significant two-fold increase in the oral clearance of chlorzoxazone in obese Type II diabetics compared with healthy volunteers and Type I diabetics. The protein binding of chlorzoxazone was not significantly different between the three groups. In contrast, Type 1 diabetics and healthy volunteers demonstrated no difference in the oral clearance of chlorzoxazone. The urinary recovery of 6-hydroxychlorzoxazone as a percentage of the administered dose was not different between healthy, Type I and obese Type II diabetics. The elimination half-life of chlorzoxazone did not differ between the three groups. CYP2E1 mRNA was significantly elevated in Type I and obese Type II diabetics compared with healthy volunteers. The oral clearance of

  7. Autophagy Protects against CYP2E1/Chronic Ethanol-Induced Hepatotoxicity

    PubMed Central

    Lu, Yongke; Cederbaum, Arthur I.

    2015-01-01

    Autophagy is an intracellular pathway by which lysosomes degrade and recycle long-lived proteins and cellular organelles. The effects of ethanol on autophagy are complex but recent studies have shown that autophagy serves a protective function against ethanol-induced liver injury. Autophagy was found to also be protective against CYP2E1-dependent toxicity in vitro in HepG2 cells which express CYP2E1 and in vivo in an acute alcohol/CYPE1-dependent liver injury model. The goal of the current report was to extend the previous in vitro and acute in vivo experiments to a chronic ethanol model to evaluate whether autophagy is also protective against CYP2E1-dependent liver injury in a chronic ethanol-fed mouse model. Wild type (WT), CYP2E1 knockout (KO) or CYP2E1 humanized transgenic knockin (KI), mice were fed an ethanol liquid diet or control dextrose diet for four weeks. In the last week, some mice received either saline or 3-methyladenine (3-MA), an inhibitor of autophagy, or rapamycin, which stimulates autophagy. Inhibition of autophagy by 3-MA potentiated the ethanol-induced increases in serum transaminase and triglyceride levels in the WT and KI mice but not KO mice, while rapamycin prevented the ethanol liver injury. Treatment with 3-MA enhanced the ethanol-induced fat accumulation in WT mice and caused necrosis in the KI mice; little or no effect was found in the ethanol-fed KO mice or any of the dextrose-fed mice. 3-MA treatment further lowered the ethanol-decrease in hepatic GSH levels and further increased formation of TBARS in WT and KI mice, whereas rapamycin blunted these effects of ethanol. Neither 3-MA nor rapamycin treatment affected CYP2E1 catalytic activity or content or the induction CYP2E1 by ethanol. The 3-MA treatment decreased levels of Beclin-1 and Atg 7 but increased levels of p62 in the ethanol-fed WT and KI mice whereas rapamycin had the opposite effects, validating inhibition and stimulation of autophagy, respectively. These results suggest

  8. Cytochrome p450 2E1 polymorphisms and the risk of gastric cardia cancer

    PubMed Central

    Cai, Lin; Zheng, Zong-Li; Zhang, Zuo-Feng

    2005-01-01

    AIM: Genetic polymorphisms of drug-metabolizing enzymes have recently been shown to affect susceptibility to chemical carcinogenesis. Cytochrome P450 2E1 (CYP2E1) enzyme catalyzes the metabolism of many procarcinogens, such as N-nitrosamines and related compounds. The gene coding for this enzyme is polymorphic and thus may play a role in gastric cardia cancer (GCC) etiology. In this hospital-based case-control study, we evaluate the relationship between genetic polymorphisms of CYP2E1 and the risk of GCC. METHODS: The study subjects comprised 159 histologically confirmed GCC cases identified via hospital cancer registry and surgical records at five hospitals in Fuzhou, Fujian Province, China, between April and November 2001. Controls were 192 patients admitted to the same hospitals for nonmalignant conditions. The genotypes of CYP2E1 were detected by a PCR-based RFLP assay. The odds ratios were estimated by logistic regression analyses and were adjusted for potential confounding factors. RESULTS: The distribution of three genotypes of CYP2E1 in GCC cases and controls was significantly different (χ2 = 16.04, P<0.01). The frequency of the CYP2E1 (c1/c1) genotype in GCC cases and controls was 60.4% and 40.1%, respectively. The CYP2E1 (c1/c1) genotype was associated with an increased risk for GCC (the adjusted (OR) was 2.37, 95% confidence interval (CI): 1.52-3.70). Subjects who carried the CYP2E1 (c1/c1) genotype and were habitual smokers were at a significantly higher risk of developing GCC (OR = 4.68, 95%CI: 2.19-10.04) compared with those who had the CYP2E1 (c1/c2 or c2/c2) genotype and did not smoke. CONCLUSION: These results suggest that the CYP2E1 genotype may influence individual susceptibility to development of GCC, and that the risk increases significantly in smokers. PMID:15793883

  9. 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

  10. Non-Carriers of Reduced-Function CYP2C19 Alleles are Most Susceptible to Impairment of the Anti-Platelet Effect of Clopidogrel by Proton-Pump Inhibitors: A Pilot Study

    PubMed Central

    Lee, Jen-Kuang; Wu, Cho-Kai; Juang, Jyh-Ming; Tsai, Chia-Ti; Hwang, Juey-Jen; Lin, Jiuun-Lee; Chiang, Fu-Tien

    2016-01-01

    Background The phenomenon of CYP2C19 polymorphism affects the metabolism of both clopidogrel and proton-pump inhibitors (PPI). However, concomitant use of both drugs may reduce the desired therapeutic effects. In this study, we evaluated whether individuals with different numbers of reduced-function CYP2C19 alleles were equally affected and whether PPIs with different dependencies on CYP2C19 metabolism were equally involved. Methods Thirty healthy volunteers were recruited to a six-week regimen of clopidogrel. Three PPIs with different metabolic dependencies on CYP2C19 were included and separately administered in this order. Each PPI was given for a week, followed by a one-week washout period before the intervention of the next PPI. The anti-platelet effect was examined by Thromboelastography Platelet MappingTM (TEG®) and vasodilator-stimulated phosphoprotein (VASP) assays. Results Both TEG® and VASP tests showed the same general qualitative trend, but TEG® detected a statistically significant fluctuation of platelet aggregation in response to different drug interventions. The TEG® results also demonstrated that non-carriers experienced the most significant impairment of anti-platelet effect of clopidogrel after concomitant use of PPIs. This impairment was closely related to the metabolic dependence on CYP2C19 of PPI. Conclusions Our study indicated that non-carriers of reduced-function CYP2C19 alleles are most susceptible to impairment of the anti-platelet effect of clopidogrel after concomitant PPI use. Individual subjects are not equally affected, and PPIs are not equally involved. However, large-scale randomized clinical trials are needed to evaluate the clinical outcome. PMID:27122952

  11. Cooperative effects for CYP2E1 differ between styrene and its metabolites

    PubMed Central

    Hartman, Jessica H.; Boysen, Gunnar; Miller, Grover P.

    2014-01-01

    Cooperative interactions are frequently observed in the metabolism of drugs and pollutants by cytochrome P450s; nevertheless, the molecular determinants for cooperativity remain elusive. Previously, we demonstrated that steady-state styrene metabolism by CYP2E1 exhibits positive cooperativity.We hypothesized that styrene metabolites have lower affinity than styrene toward CYP2E1 and limited ability to induce cooperative effects during metabolism. To test the hypothesis, we determined the potency and mechanism of inhibition for styrene and its metabolites toward oxidation of 4-nitrophenol using CYP2E1 Supersomes® and human liver microsomes.Styrene inhibited the reaction through a mixed cooperative mechanism with high affinity for the catalytic site (67 μM) and lower affinity for the cooperative site (1100 μM), while increasing substrate turnover at high concentrations. Styrene oxide and 4-vinylphenol possessed similar affinity for CYP2E1. Styrene oxide behaved cooperatively like styrene, but 4-vinylphenol decreased turnover at high concentrations. Styrene glycol was a very poor competitive inhibitor. Among all compounds, there was a positive correlation with binding and hydrophobicity.Taken together, these findings for CYP2E1 further validate contributions of cooperative mechanisms to metabolic processes, demonstrate the role of molecular structure on those mechanisms and underscore the potential for heterotropic cooperative effects between different compounds. PMID:23327532

  12. Effect of BI-1 on insulin resistance through regulation of CYP2E1

    PubMed Central

    Lee, Geum-Hwa; Oh, Kyoung-Jin; Kim, Hyung-Ryong; Han, Hye-Sook; Lee, Hwa-Young; Park, Keun-Gyu; Nam, Ki-Hoan; Koo, Seung-Hoi; Chae, Han-Jung

    2016-01-01

    Diet-induced obesity is a major contributing factor to the progression of hepatic insulin resistance. Increased free fatty acids in liver enhances endoplasmic reticulum (ER) stress and production of reactive oxygen species (ROS), both are directly responsible for dysregulation of hepatic insulin signaling. BI-1, a recently studied ER stress regulator, was examined to investigate its association with ER stress and ROS in insulin resistance models. To induce obesity and insulin resistance, BI-1 wild type and BI-1 knock-out mice were fed a high-fat diet for 8 weeks. The BI-1 knock-out mice had hyperglycemia, was associated with impaired glucose and insulin tolerance under high-fat diet conditions. Increased activity of NADPH-dependent CYP reductase-associated cytochrome p450 2E1 (CYP2E1) and exacerbation of ER stress in the livers of BI-1 knock-out mice was also observed. Conversely, stable expression of BI-1 in HepG2 hepatocytes was shown to reduce palmitate-induced ER stress and CYP2E1-dependent ROS production, resulting in the preservation of intact insulin signaling. Stable expression of CYP2E1 led to increased ROS production and dysregulation of insulin signaling in hepatic cells, mimicking palmitate-mediated hepatic insulin resistance. We propose that BI-1 protects against obesity-induced hepatic insulin resistance by regulating CYP2E1 activity and ROS production. PMID:27576594

  13. Effect of BI-1 on insulin resistance through regulation of CYP2E1.

    PubMed

    Lee, Geum-Hwa; Oh, Kyoung-Jin; Kim, Hyung-Ryong; Han, Hye-Sook; Lee, Hwa-Young; Park, Keun-Gyu; Nam, Ki-Hoan; Koo, Seung-Hoi; Chae, Han-Jung

    2016-01-01

    Diet-induced obesity is a major contributing factor to the progression of hepatic insulin resistance. Increased free fatty acids in liver enhances endoplasmic reticulum (ER) stress and production of reactive oxygen species (ROS), both are directly responsible for dysregulation of hepatic insulin signaling. BI-1, a recently studied ER stress regulator, was examined to investigate its association with ER stress and ROS in insulin resistance models. To induce obesity and insulin resistance, BI-1 wild type and BI-1 knock-out mice were fed a high-fat diet for 8 weeks. The BI-1 knock-out mice had hyperglycemia, was associated with impaired glucose and insulin tolerance under high-fat diet conditions. Increased activity of NADPH-dependent CYP reductase-associated cytochrome p450 2E1 (CYP2E1) and exacerbation of ER stress in the livers of BI-1 knock-out mice was also observed. Conversely, stable expression of BI-1 in HepG2 hepatocytes was shown to reduce palmitate-induced ER stress and CYP2E1-dependent ROS production, resulting in the preservation of intact insulin signaling. Stable expression of CYP2E1 led to increased ROS production and dysregulation of insulin signaling in hepatic cells, mimicking palmitate-mediated hepatic insulin resistance. We propose that BI-1 protects against obesity-induced hepatic insulin resistance by regulating CYP2E1 activity and ROS production. PMID:27576594

  14. A randomized controlled trial to assess the efficacy and safety of doubling dose clopidogrel versus ticagrelor for the treatment of acute coronary syndrome in patients with CYP2C19*2 homozygotes

    PubMed Central

    Xiong, Ran; Liu, Wenxian; Chen, Liying; Kang, Tieduo; Ning, Shangqiu; Li, Jiang

    2015-01-01

    Background: Compared with non-reversible, indirect P2Y12 inhibitor clopidogrel, ticagrelor is a reversible, direct acting inhibitor. The CYP2C19*2 allele is a common genetic variant in individuals that need given higher clopidogrel in acute coronary syndrome patients. Objective: We aimed to assess a pharmacogenetic approach of doubling dose clopidogrel compare with standard dose of ticagrelor among carriers with the CYP2C19*2 homozygotes. Materials and methods: We compared ticagrelor (180 mg loading dose, 90 mg twice daily thereafter) with clopidogrel (600 mg loading dose, 150 mg daily thereafter) for the prevention of cardiovascular events in CYP2C19*2 homozygotes patients admitted to the hospital with an acute coronary syndrome, with or without ST-segment elevation. Results: After genetic test to identify carriers of the CYP2C19*2 allele from 2295 patients, 224 cases with CYP2C19*2 homozygotes were enrolled into our prospective, randomized trial. Patients were random assignment with colpidogrel group (n = 112) and ticagrelor group (n = 112). The two groups were similar in terms of baseline characteristics. After the first 600 mg loading dose of clopidogrel, patients carrying two CYP2C19*2 allele had weaker PRU inhibition (39.8±37.4 vs 27.9±12.4; P = 0.001) and more bleeding adverse events (20.5% vs. 7.1%; hazard ratio = 2.88; 95% [CI], 1.34-6.15; P = 0.001) compared to those taking standard dose of ticagrelor. Conclusions: In CYP2C19*2 carriers with ACS, ticagrlor is as effective as high clopidogrel in reducing platelet reactivity, particularly in first days. This study suggests that ticagrelor may be much better than doubling dose clopidogrel in patients with CYP2C19*2 in according to platelet reactivity monitoring. Use of ticagrelor instead of clopidogrel may eliminate the need for genetic testing and lead to less mild bleeding adverse. PMID:26550258

  15. Regulation of the effects of CYP2E1-induced oxidative stress by JNK signaling

    PubMed Central

    Schattenberg, Jörn M.; Czaja, Mark J.

    2014-01-01

    The generation of excessive amounts of reactive oxygen species (ROS) leads to cellular oxidative stress that underlies a variety of forms of hepatocyte injury and death including that from alcohol. Although ROS can induce cell damage through direct effects on cellular macromolecules, the injurious effects of ROS are mediated largely through changes in signal transduction pathways such as the mitogen-activated protein kinase c-Jun N-terminal kinase (JNK). In response to alcohol, hepatocytes have increased levels of the enzyme cytochrome P450 2E1 (CYP2E1) which generates an oxidant stress that promotes the development of alcoholic steatosis and liver injury. These effects are mediated in large part through overactivation of JNK that alters cell death pathways. Targeting the JNK pathway or its downstream effectors may be a useful therapeutic approach to the oxidative stress generated by CYP2E1 in alcoholic liver disease. PMID:25462060

  16. CYP2E1-dependent elevation of serum cholesterol, triglycerides, and hepatic bile acids by isoniazid

    SciTech Connect

    Cheng, Jie; Krausz, Kristopher W.; Li, Feng; Ma, Xiaochao; Gonzalez, Frank J.

    2013-01-15

    Isoniazid is the first-line medication in the prevention and treatment of tuberculosis. Isoniazid is known to have a biphasic effect on the inhibition–induction of CYP2E1 and is also considered to be involved in isoniazid-induced hepatotoxicity. However, the full extent and mechanism of involvement of CYP2E1 in isoniazid-induced hepatotoxicity remain to be thoroughly investigated. In the current study, isoniazid was administered to wild-type and Cyp2e1-null mice to investigate the potential toxicity of isoniazid in vivo. The results revealed that isoniazid caused no hepatotoxicity in wild-type and Cyp2e1-null mice, but produced elevated serum cholesterol and triglycerides, and hepatic bile acids in wild-type mice, as well as decreased abundance of free fatty acids in wild-type mice and not in Cyp2e1-null mice. Metabolomic analysis demonstrated that production of isoniazid metabolites was elevated in wild-type mice along with a higher abundance of bile acids, bile acid metabolites, carnitine and carnitine derivatives; these were not observed in Cyp2e1-null mice. In addition, the enzymes responsible for bile acid synthesis were decreased and proteins involved in bile acid transport were significantly increased in wild-type mice. Lastly, treatment of targeted isoniazid metabolites to wild-type mice led to similar changes in cholesterol, triglycerides and free fatty acids. These findings suggest that while CYP2E1 is not involved in isoniazid-induced hepatotoxicity, while an isoniazid metabolite might play a role in isoniazid-induced cholestasis through enhancement of bile acid accumulation and mitochondria β-oxidation. -- Highlights: ► Isoniazid metabolites were elevated only in wild-type mice. ► Isoniazid caused no hepatotoxicity in wild-type and Cyp2e1-null mice. ► Isoniazid elevated serum cholesterol and triglycerides, and hepatic bile acids. ► Bile acid transporters were significantly decreased in isoniazid-treated mice.

  17. 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. PMID:23393220

  18. Pharmacokinetic Interactions between Monoamine Oxidase A Inhibitor Harmaline and 5-Methoxy-N,N-Dimethyltryptamine, and the Impact of CYP2D6 Status

    PubMed Central

    Jiang, Xi-Ling; Shen, Hong-Wu; Mager, Donald E.

    2013-01-01

    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. PMID:23393220

  19. Determinants of the substrate specificity of human cytochrome P-450 CYP2D6: design and construction of a mutant with testosterone hydroxylase activity.

    PubMed Central

    Smith, G; Modi, S; Pillai, I; Lian, L Y; Sutcliffe, M J; Pritchard, M P; Friedberg, T; Roberts, G C; Wolf, C R

    1998-01-01

    Cytochrome P-450 CYP2D6, human debrisoquine hydroxylase, metabolizes more than 30 prescribed drugs, the vast majority of which are small molecules containing a basic nitrogen atom. In contrast, the similar mouse protein Cyp2d-9 was first characterized as a testosterone 16alpha-hydroxylase. No common substrates have been reported for the two enzymes. Here we investigate the structural basis of this difference in substrate specificity. We have earlier used a combination of NMR data and homology modelling to generate a three-dimensional model of CYP2D6 [Modi, Paine, Sutcliffe, Lian, Primrose, Wolf, C.R. and Roberts (1996) Biochemistry 35, 4541-4550]. We have now generated a homology model of Cyp2d-9 and compared the two models to identify specific amino acid residues that we believe form the substrate-binding site in each protein and therefore influence catalytic selectivity. Although there are many similarities in active site structure, the most notable difference is a phenylalanine residue (Phe-483) in CYP2D6, which in the model is located such that the bulky phenyl ring is positioned across the channel mouth, thus limiting the size of substrate that can access the active site. In Cyp2d-9, the corresponding position is occupied by an isoleucine residue, which imposes fewer steric restraints on the size of substrate that can access the active site. To investigate whether the amino acid residue at this position does indeed influence the catalytic selectivity of these enzymes, site-directed mutagenesis was used to change Phe-483 in CYP2D6 to isoleucine and also to tryptophan. CYP2D6, Cyp2d-9 and both mutant CYP2D6 proteins were co-expressed with NADPH cytochrome P-450 reductase as a functional mono-oxygenase system in Escherichia coli and their relative catalytic activities towards bufuralol and testosterone were determined. All four proteins exhibited catalytic activity towards bufuralol but only Cyp2d-9 catalysed the formation of 16alpha-hydroxytesterone. Uniquely

  20. 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

  1. 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.

  2. CYP1A2 and CYP2D6 Gene Polymorphisms in Schizophrenic Patients with Neuroleptic Drug-Induced Side Effects.

    PubMed

    Ivanova, S A; Filipenko, M L; Vyalova, N M; Voronina, E N; Pozhidaev, I V; Osmanova, D Z; Ivanov, M V; Fedorenko, O Yu; Semke, A V; Bokhan, N A

    2016-03-01

    Polymorphic variants of CYP1A2 and CYP2D6 genes of the cytochrome P450 system were studied in patients with schizophrenia with drug-induced motor disorders and hyperprolactinemia against the background of long-term neuroleptic therapy. We revealed an association of polymorphic variant C-163A CYP1A2*1F of CYP1A2 gene with tardive dyskinesia and association of polymorphic variant 1846G>A CY2D6*4 and genotype A/A of CYP2D6 gene (responsible for debrisoquin-4-hydroxylase synthesis) with limbotruncal tardive dyskinesia in patients with schizophrenia receiving neuroleptics for a long time. PMID:27021090

  3. NOVEL ASSAY TO ASSESS CYP-2E1-LIKE ACTIVITY IN THE JAPANESE MEDAKA (ORYZIAS LATIPES).

    EPA Science Inventory

    Liver microsomes and S-9 fraction of Japanese medaka (Oryzias latipes) metabolized the CYP2E1 specific substrate, p-nitrophenol (PNP), to a single hydroxylated product, 4-nitrocatechol. The use of liver S-9 fraction proved to be a viable alternative to liver microsomes and allowe...

  4. Induction of CYP2E1 in non-alcoholic fatty liver diseases.

    PubMed

    Aljomah, Ghanim; Baker, Susan S; Liu, Wensheng; Kozielski, Rafal; Oluwole, Janet; Lupu, Benita; Baker, Robert D; Zhu, Lixin

    2015-12-01

    Mounting evidence supports a contribution of endogenous alcohol metabolism in the pathogenesis of non-alcoholic steatohepatitis (NASH). However, it is not known whether the expression of alcohol metabolism genes is altered in the livers of simple steatosis. There is also a current debate on whether fatty acids induce CYP2E1 in fatty livers. In this study, expression of alcohol metabolizing genes in the liver biopsies of simple steatosis patients was examined by quantitative real-time PCR (qRT-PCR), in comparison to biopsies of NASH livers and normal controls. Induction of alcohol metabolizing genes was also examined in cultured HepG2 cells treated with ethanol or oleic acid, by qRT-PCR and Western blots. We found that the mRNA expression of alcohol metabolizing genes including ADH1C, ADH4, ADH6, catalase and CYP2E1 was elevated in the livers of simple steatosis, to similar levels found in NASH livers. In cultured HepG2 cells, ethanol induced the expression of CYP2E1 mRNA and protein, but not ADH4 or ADH6; oleic acid did not induce any of these genes. These results suggest that elevated alcohol metabolism may contribute to the pathogenesis of NAFLD at the stage of simple steatosis as well as more severe stages. Our in vitro data support that CYP2E1 is induced by endogenous alcohol but not by fatty acids. PMID:26551085

  5. 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

  6. Benzene metabolism by human liver microsomes in relation to cytochrome P450 2E1 activity.

    PubMed

    Seaton, M J; Schlosser, P M; Bond, J A; Medinsky, M A

    1994-09-01

    Low levels of benzene from sources including cigarette smoke and automobile emissions are ubiquitous in the environment. Since the toxicity of benzene probably results from oxidative metabolites, an understanding of the profile of biotransformation of low levels of benzene is critical in making a valid risk assessment. To that end, we have investigated metabolism of a low concentration of [14C]benzene (3.4 microM) by microsomes from human, mouse and rat liver. The extent of phase I benzene metabolism by microsomal preparations from 10 human liver samples and single microsomal preparations from both mice and rats was then related to measured activities of cytochrome P450 (CYP) 2E1. Measured CYP 2E1 activities, as determined by hydroxylation of p-nitrophenol, varied 13-fold (0.253-3.266 nmol/min/mg) for human samples. The fraction of benzene metabolized in 16 min ranged from 10% to 59%. Also at 16 min, significant amounts of oxidative metabolites were formed. Phenol was the main metabolite formed by all but two human microsomal preparations. In those samples, both of which had high CYP 2E1 activity, hydroquinone was the major metabolite formed. Both hydroquinone and catechol formation showed a direct correlation with CYP 2E1 activity over the range of activities present. A simulation model was developed based on a mechanism of competitive inhibition between benzene and its oxidized metabolites, and was fit to time-course data for three human liver preparations. Model calculations for initial rates of benzene metabolism ranging from 0.344 to 4.442 nmol/mg/min are directly proportional to measured CYP 2E1 activities. The model predicted the dependence of benzene metabolism on the measured CYP 2E1 activity in human liver samples, as well as in mouse and rat liver samples. These results suggest that differences in measured hepatic CYP 2E1 activity may be a major factor contributing to both interindividual and interspecies variations in hepatic metabolism of benzene

  7. Population pharmacokinetic modelling to assess the impact of CYP2D6 and CYP3A metabolic phenotypes on the pharmacokinetics of tamoxifen and endoxifen

    PubMed Central

    ter Heine, Rob; Binkhorst, Lisette; de Graan, Anne Joy M; de Bruijn, Peter; Beijnen, Jos H; Mathijssen, Ron H J; Huitema, Alwin D R

    2014-01-01

    Aims Tamoxifen is considered a pro-drug of its active metabolite endoxifen. The major metabolic enzymes involved in endoxifen formation are CYP2D6 and CYP3A. There is considerable evidence that variability in activity of these enzymes influences endoxifen exposure and thereby may influence the clinical outcome of tamoxifen treatment. We aimed to quantify the impact of metabolic phenotype on the pharmacokinetics of tamoxifen and endoxifen. Methods We assessed the CYP2D6 and CYP3A metabolic phenotypes in 40 breast cancer patients on tamoxifen treatment with a single dose of dextromethorphan as a dual phenotypic probe for CYP2D6 and CYP3A. The pharmacokinetics of dextromethorphan, tamoxifen and their relevant metabolites were analyzed using non-linear mixed effects modelling. Results Population pharmacokinetic models were developed for dextromethorphan, tamoxifen and their metabolites. In the final model for tamoxifen, the dextromethorphan derived metabolic phenotypes for CYP2D6 as well as CYP3A significantly (P < 0.0001) explained 54% of the observed variability in endoxifen formation (inter-individual variability reduced from 55% to 25%). Conclusions We have shown that not only CYP2D6, but also CYP3A enzyme activity influences the tamoxifen to endoxifen conversion in breast cancer patients. Our developed model may be used to assess separately the impact of CYP2D6 and CYP3A mediated drug–drug interactions with tamoxifen without the necessity of administering this anti-oestrogenic drug and to support Bayesian guided therapeutic drug monitoring of tamoxifen in routine clinical practice. PMID:24697814

  8. Significant Effect of Polymorphisms in CYP2D6 and ABCC2 on Clinical Outcomes of Adjuvant Tamoxifen Therapy for Breast Cancer Patients

    PubMed Central

    Kiyotani, Kazuma; Mushiroda, Taisei; Imamura, Chiyo K.; Hosono, Naoya; Tsunoda, Tatsuhiko; Kubo, Michiaki; Tanigawara, Yusuke; Flockhart, David A.; Desta, Zeruesenay; Skaar, Todd C.; Aki, Fuminori; Hirata, Koichi; Takatsuka, Yuichi; Okazaki, Minoru; Ohsumi, Shozo; Yamakawa, Takashi; Sasa, Mitsunori; Nakamura, Yusuke; Zembutsu, Hitoshi

    2010-01-01

    Purpose The clinical efficacy of tamoxifen is suspected to be influenced by the activity of drug-metabolizing enzymes and transporters involved in the formation, metabolism, and elimination of its active forms. We investigated relationships of polymorphisms in transporter genes and CYP2D6 to clinical outcome of patients receiving tamoxifen. Patients and Methods We studied 282 patients with hormone receptor–positive, invasive breast cancer receiving tamoxifen monotherapy, including 67 patients who have been previously reported. We investigated the effects of allelic variants of CYP2D6 and haplotype-tagging single nucleotide polymorphisms (tag-SNPs) of ABCB1, ABCC2, and ABCG2 on recurrence-free survival using the Kaplan-Meier method and Cox regression analysis. Plasma concentrations of tamoxifen metabolites were measured in 98 patients receiving tamoxifen 20 mg/d. Results CYP2D6 variants were significantly associated with shorter recurrence-free survival (P = .000036; hazard ratio [HR] = 9.52; 95% CI, 2.79 to 32.45 in patients with two variant alleles v patients without variant alleles). Among 51 tag-SNPs in transporter genes, a significant association was found at rs3740065 in ABCC2 (P = .00017; HR = 10.64; 95% CI, 1.44 to 78.88 in patients with AA v GG genotypes). The number of risk alleles of CYP2D6 and ABCC2 showed cumulative effects on recurrence-free survival (P = .000000055). Patients carrying four risk alleles had 45.25-fold higher risk compared with patients with ≤ one risk allele. CYP2D6 variants were associated with lower plasma levels of endoxifen and 4-hydroxytamoxifen (P = .0000043 and .00052), whereas no significant difference was found among ABCC2 genotype groups. Conclusion Our results suggest that polymorphisms in CYP2D6 and ABCC2 are important predictors for the prognosis of patients with breast cancer treated with tamoxifen. PMID:20124171

  9. Cytochrome P450 2E1 inhibition prevents hepatic carcinogenesis induced by diethylnitrosamine in alcohol-fed rats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chronic alcohol ingestion increases hepatic cytochrome P450 2E1 (CYP2E1), which is associated with hepatocarcinogenesis. We investigated whether treatment with chlormethiazole (CMZ), a CYP2E1 inhibitor, protects against alcohol-associated hepatic carcinogenesis in rats. Rats were fed either an ethan...

  10. CYP2E1 and NQO1 genotypes and bladder cancer risk in a Lebanese population.

    PubMed

    Basma, Hussein A; Kobeissi, Loulou H; Jabbour, Michel E; Moussa, Mohamad A; Dhaini, Hassan R

    2013-01-01

    Urinary bladder cancer incidence in Lebanon ranks among the highest in the world. Cytochrome P450 2E1 (CYP2E1), NAD(P)H quinone oxidoreductase1 (NQO1), and N-Acetyltransferase1 (NAT1), are drug-metabolizing enzymes (DMEs) involved in the metabolism of carcinogens, such as arylamines and heterocyclic amines, implicated in bladder cancer. The present study attempts to investigate the role of these DMEs genetic polymorphism in bladder cancer risk among Lebanese men. 54 cases and 106 controls were recruited from two hospitals in Beirut. An interview-based questionnaire was administered to assess suspected environmental and occupational risk factors. PCR-RFLP was performed on blood-based DNA samples to determine DMEs genotypes. Associations between bladder cancer and putative risk factors were measured using adjusted odds ratios (ORs) and their 95% confidence intervals (CIs). Results showed CYP2E1 c1/c1, NAT1*14A, and smoking, to be risk factors for bladder cancer. No significant differences in frequency distribution of the NQO1 genotypes were found in cases versus controls. The odds of carrying the CYP2E1 c1/c1 genotype were 4 times higher in cases compared to controls (OR=3.97, 95% CI: 0.48-32.7). The odds of carrying at least one NAT1*14A allele were 14 times higher in cases versus controls (OR=14.4, 95% CI: 1.016-204.9). Our study suggests CYP2E1 c1/c1, NAT1*14A, and smoking, as potential risk factors for bladder cancer in Lebanese. Further studies with larger samples must be conducted to confirm these findings. PMID:24319536

  11. CYP2E1 and NQO1 genotypes and bladder cancer risk in a Lebanese population

    PubMed Central

    Basma, Hussein A; Kobeissi, Loulou H; Jabbour, Michel E; Moussa, Mohamad A; Dhaini, Hassan R

    2013-01-01

    Urinary bladder cancer incidence in Lebanon ranks among the highest in the world. Cytochrome P450 2E1 (CYP2E1), NAD(P)H quinone oxidoreductase1 (NQO1), and N-Acetyltransferase1 (NAT1), are drug-metabolizing enzymes (DMEs) involved in the metabolism of carcinogens, such as arylamines and heterocyclic amines, implicated in bladder cancer. The present study attempts to investigate the role of these DMEs genetic polymorphism in bladder cancer risk among Lebanese men. 54 cases and 106 controls were recruited from two hospitals in Beirut. An interview-based questionnaire was administered to assess suspected environmental and occupational risk factors. PCR-RFLP was performed on blood-based DNA samples to determine DMEs genotypes. Associations between bladder cancer and putative risk factors were measured using adjusted odds ratios (ORs) and their 95% confidence intervals (CIs). Results showed CYP2E1 c1/c1, NAT1*14A, and smoking, to be risk factors for bladder cancer. No significant differences in frequency distribution of the NQO1 genotypes were found in cases versus controls. The odds of carrying the CYP2E1 c1/c1 genotype were 4 times higher in cases compared to controls (OR=3.97, 95% CI: 0.48-32.7). The odds of carrying at least one NAT1*14A allele were 14 times higher in cases versus controls (OR=14.4, 95% CI: 1.016-204.9). Our study suggests CYP2E1 c1/c1, NAT1*14A, and smoking, as potential risk factors for bladder cancer in Lebanese. Further studies with larger samples must be conducted to confirm these findings. PMID:24319536

  12. 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

  13. Pharmacogenetic evaluation of ABCB1, Cyp2C9, Cyp2C19 and methylene tetrahydrofolate reductase polymorphisms in teratogenicity of anti-epileptic drugs in women with epilepsy

    PubMed Central

    Jose, Manna; Banerjee, Moinak; Mathew, Anila; Bharadwaj, Tashi; Vijayan, Neetha; Thomas, Sanjeev V.

    2014-01-01

    Aim: Pregnancy in women with epilepsy (WWE) who are on anti-epileptic drugs (AEDs) has two- to three-fold increased risk of fetal malformations. AEDs are mostly metabolized by Cyp2C9, Cyp2C19 and Cyp3A4 and transported by ABCB1. Patients on AED therapy can have folate deficiency. We hypothesize that the polymorphisms in ABCB1, Cyp2C9, Cyp2C19 and methylene tetrahydrofolate reductase (MTHFR) might result in differential expression resulting in differential drug transport, drug metabolism and folate metabolism, which in turn may contribute to the teratogenic impact of AEDs. Materials and Methods: The ABCB1, Cyp2C9, Cyp2C19 and MTHFR polymorphisms were genotyped for their role in teratogenic potential and the nature of teratogenecity in response to AED treatment in WWE. The allelic, genotypic associations were tested in 266 WWE comprising of 143 WWE who had given birth to babies with WWE-malformation (WWE-M) and 123 WWE who had normal offsprings (WWE-N). Results: In WWE-M, CC genotype of Ex07 + 139C/T was overrepresented (P = 0.0032) whereas the poor metabolizer allele *2 and *2 *2 genotype of CYP2C219 was significantly higher in comparison to WWE-N group (P = 0.007 and P = 0.005, respectively). All these observations were independent of the nature of malformation (cardiac vs. non cardiac malformations). Conclusion: Our study indicates the possibility that ABCB1 and Cyp2C19 may play a pivotal role in the AED induced teratogenesis, which is independent of nature of malformation. This is one of the first reports indicating the pharmacogenetic role of Cyp2C19 and ABCB1 in teratogenesis of AED in pregnant WWE. PMID:25221392

  14. Concomitant use of selective serotonin reuptake inhibitors with other cytochrome P450 2D6 or 3A4 metabolized medications: how often does it really happen?

    PubMed

    Gregor, K J; Way, K; Young, C H; James, S P

    1997-10-01

    This study retrospectively examines the one-month concomitant use of cytochrome P450 2D6 or 3A4 metabolized medications in 544,309 patients who were also receiving selective serotonin reuptake inhibitors (SSRIs). Overall, 25.53% of SSRI patients experienced concomitant use with at least one of the 33 studied CYP 2D6 or 3A4 metabolized medications. Certain drugs and drug classes were more likely to be used concurrently among SSRI patients (e.g., benzodiazepines, tricyclic antidepressants, calcium channel blockers). Similarly, of the SSRI patients experiencing concomitant use, this concurrent use was twice as likely with cytochrome P450 medications metabolized by the 3A4 isoenzyme as with those metabolized by the 2D6 isoenzyme. Finally, the vast majority (80.9%) of SSRI patients experiencing concomitant use did so with one CYP 2D6 or 3A4 metabolized medication. In sum, concomitant use generally was not extensive and did not appear to be differential among the fluoxetine, paroxetine, or sertraline patient comparison groups. PMID:9387087

  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. PMID:26871771

  16. Effect of Garden Cress Seeds Powder and Its Alcoholic Extract on the Metabolic Activity of CYP2D6 and CYP3A4

    PubMed Central

    Al-Jenoobi, Fahad I.; Al-Thukair, Areej A.; Abbas, Fawkeya A.; Al-Mohizea, Abdullah M.; Alkharfy, Khalid M.; Al-Suwayeh, Saleh A.

    2014-01-01

    The powder and alcoholic extract of dried seeds of garden cress were investigated for their effect on metabolic activity of CYP2D6 and CYP3A4 enzymes. In vitro and clinical studies were conducted on human liver microsomes and healthy human subjects, respectively. Dextromethorphan was used as a common marker for measuring metabolic activity of CYP2D6 and CYP3A4 enzymes. In in vitro studies, microsomes were incubated with NADPH in presence and absence of different concentrations of seeds extract. Clinical investigations were performed in two phases. In phase I, six healthy female volunteers were administered a single dose of dextromethorphan and in phase II volunteers were treated with seeds powder for seven days and dextromethorphan was administered with last dose. The O-demethylated and N-demethylated metabolites of dextromethorphan were measured as dextrorphan (DOR) and 3-methoxymorphinan (3-MM), respectively. Observations suggested that garden cress inhibits the formation of DOR and 3-MM metabolites. This inhibition of metabolite level was attributed to the inhibition of CYP2D6 and CYP3A4 activity. Garden cress decreases the level of DOR and 3-MM in urine and significantly increases the urinary metabolic ratio of DEX/DOR and DEX/3-MM. The findings suggested that garden cress seeds powder and ethanolic extract have the potential to interact with CYP2D6 and CYP3A4 substrates. PMID:24711855

  17. Identification and characterization of the 2D6 and Mr 23,000 antigens on the plasma membrane of rat spermatozoa.

    PubMed Central

    Jones, R; Brown, C R

    1987-01-01

    Previous investigations [Jones, Brown, von Glos & Gaunt (1985) Exp. Cell Res. 156, 31-44] have demonstrated the appearance of a new antigenic determinant (recognized by monoclonal antibody 2D6) on the plasma membrane of rat spermatozoa during post-testicular maturation in the epididymis. Identification of the 2D6 antigen on Western blots from one-dimensional SDS/polyacrylamide gels revealed that it co-migrated with a membrane protein (designated Mr 23,000 antigen) present on testicular and immature germ cells, suggesting that one antigen might be a modified version of the other. In the present work, however, we demonstrate that, although they have similar Mr and are present in soluble and membrane-bound forms, the 2D6 and Mr 23,000 antigens are biochemically and immunologically distinct molecules. The properties of the antigens are described and compared. The Mr 23,000 antigen is present on both testicular and cauda epididymidal spermatozoa, has a pI of 6.1, contains no detectable carbohydrate, is not tissue-specific and is degraded by V8 protease. By contrast, the 2D6 antigen is glycosylated, has a broad pI from 4.5 to 6.1, is tissue- and species-specific and is resistant to digestion with V8 protease. Its role in sperm-egg recognition is discussed. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. PMID:2439064

  18. Cytochrome P450 bio-affinity detection coupled to gradient HPLC: on-line screening of affinities to cytochrome P4501A2 and 2D6.

    PubMed

    Kool, Jeroen; van Liempd, Sebastiaan M; Harmsen, Stefan; Beckman, Joran; van Elswijk, Danny; Commandeur, Jan N M; Irth, Hubertus; Vermeulen, Nico P E

    2007-10-15

    Here we describe novel on-line human CYP1A2 and CYP2D6 Enzyme Affinity Detection (EAD) systems coupled to gradient HPLC. The use of the systems lies in the detection of individual inhibitory ligands in mixtures (e.g. metabolic mixtures or herbal extracts) towards two relevant drug metabolizing human CYPs. The systems can rapidly detect individual compounds in mixtures with affinities to CYP1A2 or 2D6. The HPLC-EAD systems were first evaluated and validated in flow injection analysis mode. IC50 values of known ligands for both CYPs, tested both in flow injection and in HPLC mode, were well comparable with those measured in microplate reader formats. Both EAD systems were also connected to gradient HPLC and used to screen known compound mixtures for the presence of CYP1A2 and 2D6 inhibitors. Finally, the on-line CYP2D6 EAD system was used to screen for the inhibitory activities of stereoisomers of a mixture of five methylenedioxy-alkylamphetamines (XTC analogs) on a chiral analytical column. PMID:17826363

  19. 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

  20. Constituents of Indonesian medicinal plant Averrhoa bilimbi and their cytochrome P450 3A4 and 2D6 inhibitory activities.

    PubMed

    Auw, Lidyawati; Subehan; Sukrasno; Kadota, Shigetoshi; Tezuka, Yasuhiro

    2015-01-01

    As constituents of Averrhoa bilimbi leaves we identified three new compounds (1-3) together with 12 known ones (4-15); their inhibitory activities on cytochrome P450 3A4 (CYP3A4) and 2D6 (CYP2D6) were examined. Among the isolated compounds, the mixture of 1 and 2, and compounds 4 and 9 showed strong inhibition on CYP3A4, but mild or no inhibition on CYP2D6. These compounds revealed the characteristics of 1) time- and concentration-dependent inhibition, 2) requirement of NADPH for the inhibition, 3) no protection by nucleophiles, and 4) suppression of the inhibition by competitive inhibitor. Thus, they are suggested to be mechanism-based inactivators of CYP3A4 and CYP2D6. The kinetic parameters for the inactivation (k(inact) and K(I)) were 0.19 min(-1) and 36.7 μM for the mixture of 1 and 2, 0.126 min(-1) and 10.5 μM for 4, and 0.29 min(-1) and 23.4 μM for 9. PMID:25920220

  1. Heterologous expression of human cytochrome P450 2E1 in HepG2 cell line

    PubMed Central

    Zhuge, Jian; Luo, Ye; Yu, Ying-Nian

    2003-01-01

    AIM: Human cytochrome P-450 2E1 (CYP2E1) takes part in the biotransformation of ethanol, acetone, many small-molecule substrates and volatile anesthetics. CYP2E1 is involved in chemical activation of many carcinogens, procarcinogens, and toxicants. To assess the metabolic and toxicological characteristics of CYP2E1, we cloned CYP2E1 cDNA and established a HepG2 cell line stably expressing recombinant CYP 2E1. METHODS: Human CYP2E1 cDNA was amplified with reverse transcription-polymerase chain reaction (RT-PCR) from total RNAs extracted from human liver and cloned into pGEM-T vector. The cDNA segment was identified by DNA sequencing and subcloned into a mammalian expression vector pREP9. A transgenic cell line was established by transfecting the recombinant plasmid of pREP9-CYP2E1 to HepG2 cells. The expression of CYP2E1 mRNA was validated by RT-PCR. The enzyme activity of CYP2E1 catalyzing oxidation of 4-nitrophenol in postmitochondrial supernate (S9) fraction of the cells was determined by spectrophotometry. The metabolic activation of HepG2-CYP2E1 cells was assayed by N-nitrosodiethylamine (NDEA) cytotoxicity and micronucleus test. RESULTS: The cloned CYP2E1 cDNA segment was identical to that reported by Umeno et al (GenBank access No. J02843). HepG2-CYP2E1 cells expressed CYP2E1 mRNA and had 4-nitrophenol hydroxylase activity (0.162 ± 0.025 nmol·min-1·mg-1 S9 protein), which were undetectable in parent HepG2 cells. HepG2-CYP2E1 cells increased the cytotoxicity and micronucleus rate of NDEA in comparison with those of HepG2 cells. CONCLUSION: The cDNA of human CYP2E1 can be successfully cloned, and a cell line, HepG2-CYP2E1, which can efficiently express mRNA and has CYP2E1 activity, is established. The cell line is useful for testing the cytotoxicity, mutagenicity and metabolism of xenobiotics, which may possibly be activated or metabolized by CYP2E1. PMID:14669323

  2. Prenatal antidepressant exposure associated with CYP2E1 DNA methylation change in neonates

    PubMed Central

    Gurnot, Cécile; Martin-Subero, Ignacio; Mah, Sarah M; Weikum, Whitney; Goodman, Sarah J; Brain, Ursula; Werker, Janet F; Kobor, Michael S; Esteller, Manel; Oberlander, Tim F; Hensch, Takao K

    2015-01-01

    Some but not all neonates are affected by prenatal exposure to serotonin reuptake inhibitor antidepressants (SRI) and maternal mood disturbances. Distinguishing the impact of these 2 exposures is challenging and raises critical questions about whether pharmacological, genetic, or epigenetic factors can explain the spectrum of reported outcomes. Using unbiased DNA methylation array measurements followed by a detailed candidate gene approach, we examined whether prenatal SRI exposure was associated with neonatal DNA methylation changes and whether such changes were associated with differences in birth outcomes. Prenatal SRI exposure was first associated with increased DNA methylation status primarily at CYP2E1(βNon-exposed = 0.06, βSRI-exposed = 0.30, FDR = 0); however, this finding could not be distinguished from the potential impact of prenatal maternal depressed mood. Then, using pyrosequencing of CYP2E1 regulatory regions in an expanded cohort, higher DNA methylation status—both the mean across 16 CpG sites (P < 0.01) and at each specific CpG site (P < 0.05)—was associated with exposure to lower 3rd trimester maternal depressed mood symptoms only in the SRI-exposed neonates, indicating a maternal mood x SRI exposure interaction. In addition, higher DNA methylation levels at CpG2 (P = 0.04), CpG9 (P = 0.04) and CpG10 (P = 0.02), in the interrogated CYP2E1 region, were associated with increased birth weight independently of prenatal maternal mood, SRI drug exposure, or gestational age at birth. Prenatal SRI antidepressant exposure and maternal depressed mood were associated with altered neonatal CYP2E1 DNA methylation status, which, in turn, appeared to be associated with birth weight. PMID:25891251

  3. Aminotriazole alleviates acetaminophen poisoning via downregulating P450 2E1 and suppressing inflammation.

    PubMed

    Jing, Yuping; Wu, Kunwei; Liu, Jiashuo; Ai, Qing; Ge, Pu; Dai, Jie; Jiang, Rong; Zhou, Dan; Che, Qian; Wan, Jingyuan; Zhang, Li

    2015-01-01

    Aminotriazole (ATZ) is commonly used as a catalase (CAT) inhibitor. We previously found ATZ attenuated oxidative liver injury, but the underlying mechanisms remain unknown. Acetaminophen (APAP) overdose frequently induces life-threatening oxidative hepatitis. In the present study, the potential hepatoprotective effects of ATZ on oxidative liver injury and the underlying mechanisms were further investigated in a mouse model with APAP poisoning. The experimental data indicated that pretreatment with ATZ dose- and time-dependently suppressed the elevation of plasma aminotransferases in APAP exposed mice, these effects were accompanied with alleviated histological abnormality and improved survival rate of APAP-challenged mice. In mice exposed to APAP, ATZ pretreatment decreased the CAT activities, hydrogen peroxide (H2O2) levels, malondialdehyde (MDA) contents, myeloperoxidase (MPO) levels in liver and reduced TNF-α levels in plasma. Pretreatment with ATZ also downregulated APAP-induced cytochrome P450 2E1 (CYP2E1) expression and JNK phosphorylation. In addition, posttreatment with ATZ after APAP challenge decreased the levels of plasma aminotransferases and increased the survival rate of experimental animals. Posttreatment with ATZ had no effects on CYP2E1 expression or JNK phosphorylation, but it significantly decreased the levels of plasma TNF-α. Our data indicated that the LD50 of ATZ in mice was 5367.4 mg/kg body weight, which is much higher than the therapeutic dose of ATZ in the present study. These data suggested that ATZ might be effective and safe in protect mice against APAP-induced hepatotoxicity, the beneficial effects might resulted from downregulation of CYP2E1 and inhibiton of inflammation. PMID:25884831

  4. Impact of cytochrome P450 2C19*2 polymorphism on intra-stent thrombus assessed by follow-up optical coherence tomography in Chinese patients receiving clopidogrel.

    PubMed

    Li, Shan; Shi, Yang; Wang, Haijun; Zhang, Wei; Liu, Jianfeng

    2015-07-01

    Cytochrome P450 (CYP) 2C19*2 polymorphism is associated with poor responsiveness to clopidogrel in patients undergoing percutaneous coronary intervention. Despite high frequency of this genetic variant in Chinese patients, its contribution to intra-stent thrombi assessed by optical coherence tomography (OCT) and major adverse cardiac events (MACE) remains unclear. A total of 198 patients who underwent follow-up OCT and simultaneous testing of CYP2C19 genotype by TaqMan assay and P2Y12 reaction unit (PRU) by VerifyNow P2Y12 assay were selected for the study. The patients were divided into three groups: non-carriers (*1/*1), carriers with one CYP2C19*2 allele (*1/*2), carriers with two CYP2C19*2 alleles (*2/*2). OCT data and MACE were compared among the three groups. The mean follow-up interval from coronary stent implantation to OCT was 360 ± 42 days, intra-stent thrombi were detected in 50 (25.2 %) patients (16.1 % for *1/*1, 27.8 % for *1/*2 and 43.8 % for *2/*2 carriers, p = 0.007). There were significantly increased PRU values among *1/*1, *1/*2 and *2/*2 carriers (200.4 ± 36.4 vs. 216.7 ± 44.6 vs. 242.8 ± 42.4, p < 0.001), as well as markedly decreased P2Y12 percent inhibition (38.6 ± 12.6 vs. 31.3 ± 13.1 vs. 23.8 ± 9.8 %, p < 0.001). Multivariate logistic regression analysis showed that the presence of CYP2C19 *2/*2 was the only independent predictor for intra-stent thrombi on OCT (OR: 3.488, 95 % CI: 1.992-9.046; p = 0.001), although both *1/*2 and *2/*2 were independent predictors for high on-clopidogrel platelet reactivity. CYP2C19*2/*2 homozygous status is associated with subclinical intra-stent thrombi in clopidogrel-treated Chinese patients. PMID:25800884

  5. Contribution of ABCB1 and CYP2D6 genotypes to the outcome of tamoxifen adjuvant treatment in premenopausal women with breast cancer.

    PubMed

    Argalácsová, S; Slanař, O; Vítek, P; Tesařová, P; Bakhouche, H; DraŽďáková, M; Bartošová, O; Zima, T; PertuŽelka, L

    2015-01-01

    Recent pre-clinical evidence suggests that the active metabolite of tamoxifen, endoxifen, is a substrate for efflux pump P-glycoprotein. The aim of our study was to evaluate, if the polymoprhisms within ABCB1 gene alter tamoxifen adjuvant treatment efficacy in premenopausal women. Totally 71 premenopausal women with estrogen receptor positive breast cancer indicated for tamoxifen adjuvant treatment were followed retrospectively for median period of 56 months. The gentic polymorphisms of CYP2D6 and ABCB1 were analyzed and potential covariates as tumor grading, staging, age at the diagnosis, comedication, quantitative positivity of ER or PR were also evaluated. Cox proportional-hazards regression model indicated that patients carrying at least one variant allele in ABCB1 rs1045642 had significantly longer time to event survival compared to wild type subjects. Non-significant trend was noted for better treatment outcome of patients carrying at least one variant allele in the SNP rs2032582, while for the CYP2D6 polymorphism poor metabolizer phenotype resulted in worse outcome in comparison to extensive metabolizers subjects with HR of 4.04 (95 % CI 0.31-52.19). Similarly, patients using CYP2D6 inhibitors had non-significantly shorter time-to-event as compared to never users resulting in hazard ratio of 2.06 (95 % CI 0.40-10.63). ABCB1 polymorphisms may affect outcome of tamoxifen adjuvant treatment in premenopausal breast cancer patiens. This factor should be taken into account in addition to the CYP2D6 polymorphism or phenotypic inhibition of CYP2D6 activity. PMID:26681084

  6. 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. PMID:25684704

  7. A Physiologically Based Pharmacokinetic Model to Predict Disposition of CYP2D6 and CYP1A2 Metabolized Drugs in Pregnant Women

    PubMed Central

    Ke, Alice Ban; Nallani, Srikanth C.; Zhao, Ping; Rostami-Hodjegan, Amin; Isoherranen, Nina

    2013-01-01

    Conducting pharmacokinetic (PK) studies in pregnant women is challenging. Therefore, we asked if a physiologically based pharmacokinetic (PBPK) model could be used to evaluate different dosing regimens for pregnant women. We refined and verified our previously published pregnancy PBPK model by incorporating cytochrome P450 CYP1A2 suppression (based on caffeine PK) and CYP2D6 induction (based on metoprolol PK) into the model. This model accounts for gestational age–dependent changes in maternal physiology and hepatic CYP3A activity. For verification, the disposition of CYP1A2–metabolized drug theophylline (THEO) and CYP2D6–metabolized drugs paroxetine (PAR), dextromethorphan (DEX), and clonidine (CLO) during pregnancy was predicted. Our PBPK model successfully predicted THEO disposition during the third trimester (T3). Predicted mean postpartum to third trimester (PP:T3) ratios of THEO area under the curve (AUC), maximum plasma concentration, and minimum plasma concentration were 0.76, 0.95, and 0.66 versus observed values 0.75, 0.89, and 0.72, respectively. The predicted mean PAR steady-state plasma concentration (Css) ratio (PP:T3) was 7.1 versus the observed value 3.7. Predicted mean DEX urinary ratio (UR) (PP:T3) was 2.9 versus the observed value 1.9. Predicted mean CLO AUC ratio (PP:T3) was 2.2 versus the observed value 1.7. Sensitivity analysis suggested that a 100% induction of CYP2D6 during T3 was required to recover the observed PP:T3 ratios of PAR Css, DEX UR, and CLO AUC. Based on these data, it is prudent to conclude that the magnitude of hepatic CYP2D6 induction during T3 ranges from 100 to 200%. Our PBPK model can predict the disposition of CYP1A2, 2D6, and 3A drugs during pregnancy. PMID:23355638

  8. A physiologically based pharmacokinetic model to predict disposition of CYP2D6 and CYP1A2 metabolized drugs in pregnant women.

    PubMed

    Ke, Alice Ban; Nallani, Srikanth C; Zhao, Ping; Rostami-Hodjegan, Amin; Isoherranen, Nina; Unadkat, Jashvant D

    2013-04-01

    Conducting pharmacokinetic (PK) studies in pregnant women is challenging. Therefore, we asked if a physiologically based pharmacokinetic (PBPK) model could be used to evaluate different dosing regimens for pregnant women. We refined and verified our previously published pregnancy PBPK model by incorporating cytochrome P450 CYP1A2 suppression (based on caffeine PK) and CYP2D6 induction (based on metoprolol PK) into the model. This model accounts for gestational age-dependent changes in maternal physiology and hepatic CYP3A activity. For verification, the disposition of CYP1A2-metabolized drug theophylline (THEO) and CYP2D6-metabolized drugs paroxetine (PAR), dextromethorphan (DEX), and clonidine (CLO) during pregnancy was predicted. Our PBPK model successfully predicted THEO disposition during the third trimester (T3). Predicted mean postpartum to third trimester (PP:T3) ratios of THEO area under the curve (AUC), maximum plasma concentration, and minimum plasma concentration were 0.76, 0.95, and 0.66 versus observed values 0.75, 0.89, and 0.72, respectively. The predicted mean PAR steady-state plasma concentration (Css) ratio (PP:T3) was 7.1 versus the observed value 3.7. Predicted mean DEX urinary ratio (UR) (PP:T3) was 2.9 versus the observed value 1.9. Predicted mean CLO AUC ratio (PP:T3) was 2.2 versus the observed value 1.7. Sensitivity analysis suggested that a 100% induction of CYP2D6 during T3 was required to recover the observed PP:T3 ratios of PAR Css, DEX UR, and CLO AUC. Based on these data, it is prudent to conclude that the magnitude of hepatic CYP2D6 induction during T3 ranges from 100 to 200%. Our PBPK model can predict the disposition of CYP1A2, 2D6, and 3A drugs during pregnancy. PMID:23355638

  9. Influence of CYP2D6 activity on the pharmacokinetics and pharmacodynamics of a single 20 mg dose of ibogaine in healthy volunteers.

    PubMed

    Glue, Paul; Winter, Helen; Garbe, Kira; Jakobi, Hannah; Lyudin, Alexander; Lenagh-Glue, Zoe; Hung, C Tak

    2015-06-01

    Conversion of ibogaine to its active metabolite noribogaine appears to be mediated primarily by CYP2D6. We compared 168 hours pharmacokinetic profiles of both analytes after a single oral 20 mg dose of ibogaine in 21 healthy subjects who had been pretreated for 6 days with placebo or the CYP2D6 inhibitor paroxetine. In placebo-pretreated subjects, ibogaine was rapidly converted to noribogaine. Median peak noribogaine concentrations occurred at 4 hours. Compared with placebo-pretreated subjects, paroxetine-pretreated subjects had rapid (Tmax  = 1.5 hours) and substantial absorption of ibogaine, with detectable levels out to 72 hours, and an elimination half-life of 10.2 hours. In this group, ibogaine was also rapidly converted to noribogaine with a median Tmax of 3 hours. Extent of noribogaine exposure was similar in both groups. CYP2D6 phenotype was robustly correlated with ibogaine AUC0-t (r = 0.82) and Cmax (r = 0.77). Active moiety (ibogaine plus noribogaine) exposure was ∼2-fold higher in paroxetine-pretreated subjects. Single 20 mg ibogaine doses were safe and well tolerated in all subjects. The doubling of exposure to active moiety in subjects with reduced CYP2D6 activity suggests it may be prudent to genotype patients awaiting ibogaine treatment, and to at least halve the intended dose of ibogaine in CYP2D6 poor metabolizers. PMID:25651476

  10. Cytochrome P450 2E1 genetic polymorphism and gastric cancer in Changle, Fujian Province

    PubMed Central

    Cai, Lin; Yu, Shun-Zhang; Zhang, Zuo-Feng

    2001-01-01

    AIM: Genetic polymorphism in enzymes of carcinogen metabolism has been found to have the influence on the susceptibility to cancer. Cytochrome P450 2E1 (CYP2E1) is considered to play an important role in the metabolic activation of procarcinogens such as N-nitrosoamines and low molecular weight organic compounds. The purpose of this study is to determine whether CYP450 2E1 polymorphisms are associated with risks of gastric cancer. METHODS: We conducted a population based case-control study in Changle county, Fujian Province, a high-risk region of gastric cancer in China. Ninety-one incident gastric cancer patients and ninety-four healthy controls were included in our study. Datas including demographic characteristcs, diet intake, and alcohol and tobacco consumption of indivduals in our study were completed by a standardized questionnaire. PCR-RFLP revealed three genotypes:heterozygote (C1/C2) and two homozygotes (C1/C1 and C2/C2) in CYP2E1. RESULTS: The frequency of variant genotypes (C1/C2 and C2/C2) in gastric cancer cases and controls was 36.3% and 24.5%, respectively. The rare homozygous C2/C2 genotype was found in 6 indivduals in gastric cancer group (6.6%), whereas there was only one in the control group (1.1%). However, there was no statistically significan difference between the two groups (two-tailed Fisher’s exact test, P = 0.066). Indivduals in gastric cancer group were more likely to carry genotype C1/C2 (odds ratio, OR = 1.50) and C2/C2 (OR = 7.34) than indivduals in control group (χ² = 4.597, for trend P = 0.032). The frequencies of genotypes with the C2 allele (C1/C2 and C2/C2 genotypes) were compared with those of genotypes without C2 allele (C1/C1 genotype) among indivduals in gastric cancer group and control group according to the pattern of gastric cancer risk factors. The results show that indivduals who exposed to these gastric cancer risk factors and carry the C2 allele seemed to have a higher risk of developing gastric cancer. CONCLUSION

  11. Heterologous expression of mouse cytochrome P450 2e1 in V79 cells: construction and characterisation of the cell line and comparison with V79 cell lines stably expressing rat P450 2E1 and human P450 2E1.

    PubMed

    Bernauer, Ulrike; Glatt, Hansruedi; Heinrich-Hirsch, Barbara; Liu, Yungang; Muckel, Eva; Vieth, Barbel; Gundert-Remy, Ursula

    2003-01-01

    A V79 Chinese hamster cell line was constructed for stable expression of mouse cytochrome P450 2e1 (Cyp2e1), as an addition to the existing cell battery consisting of cell lines stably expressing rat CYP2E1 and human CYP2E1 (V79 Cell Battery). The aim was to establish a cell battery that offers the in vitro possibility of investigating species-specific differences in the toxicity and metabolism of chemicals representing substrates for CYP2E1. The newly established cell line (V79m2E1) effectively expressed Cyp2e1 in the catalytically active form. The expression of catalytically active CYP2E1 in V79m2E1 cells was maintained over several months in culture, as demonstrated by Western Blotting and chlorzoxazone (CLX) 6-hydroxylase activity. The cells exhibited CLX 6-hydroxylase activity with a Km of 27.8 microM/l and Vmax of 40 pmol/mg protein/minute, compared with a Km of 28.2/28.6 microM/l and a Vmax of 130/60 pmol/mg protein/minute from V79r2E1/V79h2E1 cells. Furthermore, the CYP2E1-dependent mutagenicity of N-nitrosodimethylamine could be demonstrated in the V79m2E1 cells. Therefore, the new cell battery permits the interspecies comparison of CYP2E1-dependent toxicity and of metabolism of chemicals between humans and the two major rodent species--the rat and the mouse--that are usually used in classical toxicity studies. PMID:16221041

  12. Correlation Between the CYP2C19 Phenotype Status and the Results of Three Different Platelet Function Tests in Cardiovascular Disease Patients Receiving Antiplatelet Therapy: An Emphasis on Newly Introduced Platelet Function Analyzer-200 P2Y Test

    PubMed Central

    Li, Shuhua; Choi, Jae-Lim; Guo, Long Zhe; Goh, Ri-Young; Kim, Bo-Ram; Woo, Kwang-Sook; Kim, Moo-Hyun

    2016-01-01

    Background An association has been reported between CYP2C19 polymorphism and the altered antiplatelet activity of clopidogrel. We investigated this association using the newly introduced platelet function analyzer (PFA)-200 (INNOVANCE PFA-200 System; Siemens Healthcare, Germany) P2Y test. Methods Polymorphisms of CYP2C19*2, *3, *17 and the degree of inhibition of platelet function were determined in 83 patients. Three different platelet function tests were used to evaluate the degree of platelet inhibition and to check the association with genotype. Results The post-procedure PFA-200 values of extensive metabolizers (EM) patients (285.3±38.8) were higher than those of intermediate metabolizers (IM) and poor metabolizers (PM) patients (227.7±98.3 and 133.7±99.2, respectively; P=0.024). Light transmittance aggregometry (LTA) and the VerifyNow system showed that the post-procedure values for EM patients were lower than those of IM and PM patients (LTA: 24.4±15.7, 34.1±17.6, and 42.2±16.9, respectively, P<0.001; VerifyNow: 133.2±60.5, 171.5±42.6, and 218.7±59.3, respectively, P<0.001). The high residual platelet reactivity (HPR) rates were significantly different among the EM, IM, and PM groups using PFA-200 (PM:IM:EM=82.4:40.6:11.8, P<0.001). Conclusions Approximately, 59.0% of Korean patients with cardiovascular disease receiving clopidogrel had CYP2C19 loss-of-function genotypes classified as IM or PM, and the frequency was similar to the data from Asian people. The PFA-200, LTA, and VerifyNow platelet function tests revealed evidence of a significant association between the efficacy of clopidogrel and CYP2C19 genotypes. PMID:26522758

  13. 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. PMID:27154635

  14. A comparison of substrate dynamics in human CYP2E1 and CYP2A6

    SciTech Connect

    Harrelson, John P. . E-mail: harrelsonj@pacificu.edu; Henne, Kirk R.; Alonso, Darwin O.V.; Nelson, Sidney D.

    2007-01-26

    Considering the dynamic nature of CYPs, methods that reveal information about substrate and enzyme dynamics are necessary to generate predictive models. To compare substrate dynamics in CYP2E1 and CYP2A6, intramolecular isotope effect experiments were conducted, using deuterium labeled substrates: o-xylene, m-xylene, p-xylene, 2,6-dimethylnaphthalene, and 4,4'-dimethylbiphenyl. Competitive intermolecular experiments were also conducted using d{sub 0}- and d{sub 6}-labeled p-xylene. Both CYP2E1 and CYP2A6 displayed full isotope effect expression for o-xylene oxidation and almost complete suppression for dimethylbiphenyl. Interestingly (k {sub H}/k {sub D}){sub obs} for d{sub 3}-p-xylene oxidation ((k {sub H}/k {sub D}){sub obs} = 6.04 and (k {sub H}/k {sub D}){sub obs} = 5.53 for CYP2E1 and CYP2A6, respectively) was only slightly higher than (k {sub H}/k {sub D}){sub obs} for d{sub 3}-dimethylnaphthalene ((k {sub H}/k {sub D}){sub obs} = 5.50 and (k {sub H}/k {sub D}){sub obs} = 4.96, respectively). One explanation is that in some instances (k {sub H}/k {sub D}){sub obs} values are generated by the presence of two substrates-bound simultaneously to the CYP. Speculatively, if this explanation is valid, then intramolecular isotope effect experiments should be useful in the mechanistic investigation of P450 cooperativity.

  15. Cooperativity in CYP2E1 metabolism of acetaminophen and styrene mixtures.

    PubMed

    Hartman, Jessica H; Letzig, Lynda G; Roberts, Dean W; James, Laura P; Fifer, E Kim; Miller, Grover P

    2015-10-01

    Risk assessment for exposure to mixtures of drugs and pollutants relies heavily on in vitro characterization of their bioactivation and/or metabolism individually and extrapolation to mixtures assuming no interaction. Herein, we demonstrated that in vitro CYP2E1 metabolic activation of acetaminophen and styrene mixtures could not be explained through the Michaelis-Menten mechanism or any models relying on that premise. As a baseline for mixture studies with styrene, steady-state analysis of acetaminophen oxidation revealed a biphasic kinetic profile that was best described by negative cooperativity (Hill coefficient=0.72). The best-fit mechanism for this relationship involved two binding sites with differing affinities (Ks=830μM and Kss=32mM). Introduction of styrene inhibited that reaction less than predicted by simple competition and thus provided evidence for a cooperative mechanism within the mixture. Likewise, acetaminophen acted through a mixed-type inhibition mechanism to impact styrene epoxidation. In this case, acetaminophen competed with styrene for CYP2E1 (Ki=830μM and Ksi=180μM for catalytic and effector sites, respectively) and resulted in cooperative impacts on binding and catalysis. Based on modeling of in vivo clearance, cooperative interactions between acetaminophen and styrene resulted in profoundly increased styrene activation at low styrene exposure levels and therapeutic acetaminophen levels. Current Michaelis-Menten based toxicological models for mixtures such as styrene and acetaminophen would fail to detect this concentration-dependent relationship. Hence, future studies must assess the role of alternate CYP2E1 mechanisms in bioactivation of compounds to improve the accuracy of interpretations and predictions of toxicity. PMID:26225832

  16. Characterization of novel cytochrome P450 2E1 knockout rat model generated by CRISPR/Cas9.

    PubMed

    Wang, Xin; Tang, Yu; Lu, Jian; Shao, Yanjiao; Qin, Xuan; Li, Yongmei; Wang, Liren; Li, Dali; Liu, Mingyao

    2016-04-01

    A bacterial CRISPR-associated protein-9 nuclease (CRISPR/Cas9) from Streptococcus pyogenes has generated considerable excitement as a new tool to edit the targeted genome. Cytochrome P450 (CYP) 2E1 not only plays an important role in the xenobiotic metabolism and chemical toxicity, but also is involved in many kinds of diseases, such as alcoholic liver diseases and diabetes. Despite its importance, few animal models are used to predict CYP2E1 properties in physiology, pathology, as well as carcinogen activation. To establish a novel model for investigating the functions of CYP2E1 in vivo, this study has successfully generated the Cyp2e1 knockout (KO) rat model without detectable off-target effects using CRISPR/Cas9 system. The Cyp2e1 KO rats were viable and fertile and did not display any obvious physiological abnormities. The absent expression of CYP2E1 in KO rats also resulted in inactive behaviors in the metabolism of CYP2E1 substrates. The Cyp2e1 KO rats as a novel and available rodent animal model provide a powerful tool for the study of CYP2E1 in the chemical metabolism, toxicity, carcinogenicity, and its core factor in drug-drug interactions. PMID:26947455

  17. Ethanol Induction of CYP2A5: Role of CYP2E1-ROS-Nrf2 Pathway

    PubMed Central

    Lu, Yongke; Zhang, Xu Hannah

    2012-01-01

    Chronic ethanol consumption was previously shown to induce CYP2A5 in mice, and this induction of CYP2A5 by ethanol was CYP2E1 dependent. In this study, the mechanisms of CYP2E1-dependent ethanol induction of CYP2A5 were investigated. CYP2E1 was induced by chronic ethanol consumption to the same degree in wild-type (WT) mice and CYP2A5 knockout (Cyp2a5 –/–) mice, suggesting that unlike the CYP2E1-dependent ethanol induction of CYP2A5, ethanol induction of CYP2E1 is not CYP2A5 dependent. Microsomal ethanol oxidation was about 25% lower in Cyp2a5 –/– mice compared with that in WT mice, suggesting that CYP2A5 can oxidize ethanol although to a lesser extent than CYP2E1 does. CYP2A5 was induced by short-term ethanol consumption in human CYP2E1 transgenic knockin (Cyp2e1 –/– KI) mice but not in CYP2E1 knockout (Cyp2e1 –/–) mice. The redox-sensitive transcription factor nuclear factor-erythroid 2-related factor 2 (Nrf2) was also induced by acute ethanol in Cyp2e1 –/– KI mice but not in Cyp2e1 –/– mice. Ethanol induction of CYP2A5 in Nrf2 knockout (Nrf2 –/–) mice was lower compared with that in WT mice, whereas CYP2E1 induction by ethanol was comparable in WT and Nrf2 –/– mice. Antioxidants (N-acetyl-cysteine and vitamin C), which blocked oxidative stress induced by chronic ethanol in WT mice and acute ethanol in Cyp2e1 –/– KI mice, also blunted the induction of CYP2A5 and Nrf2 by ethanol but not the induction of CYP2E1 by ethanol. These results suggest that oxidative stress induced by ethanol via induction of CYP2E1 upregulates Nrf2 activity, which in turn regulates ethanol induction of CYP2A5. Results obtained from primary hepatocytes, mice gavaged with binge ethanol or fed chronic ethanol, show that Nrf2-regulated ethanol induction of CYP2A5 protects against ethanol-induced steatosis. PMID:22552773

  18. Bortezomib alleviates drug-induced liver injury by regulating CYP2E1 gene transcription

    PubMed Central

    PARK, WOO-JAE; KIM, SO-YEON; KIM, YE-RYUNG; PARK, JOO-WON

    2016-01-01

    Acute liver failure, i.e., the fatal deterioration of liver function, is the most common indication that emergency liver transplantation is necessary. Moreover, in the USA, drug-induced liver injury (DILI), including acetaminophen (APAP)-induced hepatotoxicity, is the main cause of acute liver failure. Matching a donor for liver transplantation is extremely difficult, and thus the development of a novel therapy for DILI is urgently needed. Following recent approval by the FDA of the proteasomal inhibitor bortezomib, its therapeutic effects on various human diseases, including solid and hematologic malignancies, have been validated. However, the specific action of proteasomal inhibition in cases of DILI had not been elucidated prior to this study. To examine the effects of proteasomal inhibition in DILI experimentally, male C56Bl/6 mice were injected with 1 mg bortezomib/kg before APAP treatment. Bortezomib not only alleviated APAP-induced hepatotoxicity in a time- and dose-dependent manner, it also alleviated CCl4- and thioacetamide-induced hepatotoxicity. We also noted that bortezomib significantly reduced cytochrome P450 2E1 (CYP2E1) expression and activity in the liver, which was accompanied by the induction of endoplasmic reticulum (ER) stress. In addition, bortezomib decreased hepatocyte nuclear factor-1α-induced promoter activation of CYP2E1 in Hep3B cells. By contrast, another proteasome inhibitor, MG132, did not cause ER stress and did not markedly affect CYP2E1 enzyme activity. Liver injury induced by APAP was aggravated by MG132, possibly via elevation of connexin 32 expression. This study suggests that proteasome inhibition has different effects in cases of DILI depending on the specific inhibitor being used. Furthermore, results from the mouse model indicated that bortezomib, but not MG132, was effective in alleviating DILI. ER stress induced by proteasome inhibition has previously been shown to exert various effects on DILI patients, and thus each

  19. 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.

  20. 3,4-DEHYDRODEBRISOQUINE, A NOVEL DEBRISOQUINE METABOLITE FORMED FROM 4-HYDROXYDEBRISOQUINE THAT IMPACTS THE CYP2D6 METABOLIC RATIO

    PubMed Central

    Zhen, Yueying; Slanař, Ondřej; Krausz, Kristopher W.; Chen, Chi; Slavík, Josef; McPhail, Kerry L.; Zabriskie, T. Mark; Perlík, František; Gonzalez, Frank J.; Idle, Jeffrey R.

    2006-01-01

    Considerable unexplained inter-subject variability in the debrisoquine metabolic ratio (urinary debrisoquine/4-hydroxydebrisoquine) exists within individual CYP2D6 genotypes. We speculated that debrisoquine was converted to as yet undisclosed metabolites. Thirteen healthy young volunteers, nine CYP2D6*1 homozygotes (EMs) and four CYP2D6*4 homozygotes (PMs) took 12.8 mg debrisoquine hemisulfate by mouth and collected 0–8 and 8–24 h urines, which were analyzed by GCMS before and after treatment with β-glucuronidase. Authentic 3,4-dehydrodebrisoquine was synthesized and characterized by GCMS, LC-MS/MS and 1H NMR. 3,4-Dehydrodebrisoquine is a novel metabolite of debrisoquine excreted variably in 0–24 h urine, both in EMs (3.1–27.6% dose) and PMs (0–2.1% dose). This metabolite is produced from 4-hydroxydebrisoquine in vitro by human and rat liver microsomes. A single CYP2D6*1 homozygote was administered 10.2 mg 4-hydroxydebrisoquine orally and also excreted 3,4-dehydrodebrisoquine. EMs excreted 6-hydroxydebrisoquine (0–4.8%), 8-hydroxydebrisoquine (0–1.3%) but these phenolic metabolites were not detected in PM urine. Debrisoquine and 4-hydroxydebrisoquine glucuronides were excreted in a highly genotype-dependent manner. A non-cytochrome P450 microsomal activity participates in the further metabolism of 4-hydroxydebrisoquine, which we speculate may also lead to the formation of 1- and 3-hydroxydebrisoquine and their ring-opened products. In conclusion, this study suggests that the traditional metabolic ratio is not a true measure of the debrisoquine 4-hydroxylation capacity of an individual and thus may, in part, explain the wide intragenotype variation in metabolic ratio. PMID:16782768

  1. In vitro metabolic interactions between black cohosh (Cimicifuga racemosa) and tamoxifen via inhibition of cytochromes P450 2D6 and 3A4.

    PubMed

    Li, Jinghu; Gödecke, Tanja; Chen, Shao-Nong; Imai, Ayano; Lankin, David C; Farnsworth, Norman R; Pauli, Guido F; van Breemen, Richard B; Nikolić, Dejan

    2011-08-01

    Women who experience hot flashes as a side effect of tamoxifen (TAM) therapy often try botanical remedies such as black cohosh to alleviate these symptoms. Since pharmacological activity of TAM is dependent on the metabolic conversion into active metabolites by the action of cytochromes P450 2D6 (CYP2D6) and 3A4, the objective of this study was to evaluate whether black cohosh extracts can inhibit formation of active TAM metabolites and possibly reduce its clinical efficacy. At 50 μg/mL, a 75% ethanolic extract of black cohosh inhibited formation of 4-hydroxy- TAM by 66.3%, N-desmethyl TAM by 74.6% and α-hydroxy TAM by 80.3%. In addition, using midazolam and dextromethorphan as probe substrates, this extract inhibited CYP3A4 and CYP2D6 with IC(50) values of 16.5 and 50.1 μg/mL, respectively. Eight triterpene glycosides were identified as competitive CYP3A4 inhibitors with IC(50) values ranging from 2.3-5.1 µM, while the alkaloids protopine and allocryptopine were identified as competitive CYP2D6 inhibitors with K(i) values of 78 and 122 nM, respectively. The results of this study suggests that co-administration of black cohosh with TAM might interfere with the clinical efficacy of this drug. However, additional clinical studies are needed to determine the clinical significance of these in vitro results. PMID:21827327

  2. Potent inhibition of human cytochrome P450 3A4, 2D6, and 2C9 isoenzymes by grapefruit juice and its furocoumarins.

    PubMed

    Girennavar, B; Jayaprakasha, G K; Patil, B S

    2007-10-01

    The cytochrome P450 enzyme family is the most abundant and responsible for the metabolism of more than 60% of currently marketed drugs and is considered central in many clinically important drug interactions. Seven different grapefruit and pummelo juices as well as 5 furocoumarins isolated from grapefruit juice were evaluated at different concentration on cytochrome P450 3A4 (CYP3A4), cytochrome P450 2C9 (CYP2C9), and cytochrome P450 2D6 (CYP2D6) isoenzyme activity. Grapefruit and pummelo juices were found to be potent inhibitors of cytochrome CYP3A4 and CYP2C9 isoenzymes at 25% concentration, while CYP2D6 is inhibited significantly low at all the tested concentration of juices (P < 0.05). Among the 5 furocoumarins tested, the inhibitory potency was in the order of paradisin A > dihydroxybergamottin > bergamottin > bergaptol > geranylcoumarin at 0.1 microM to 0.1 mM concentrations. The IC(50) value was lowest for paradisin A for CYP3A4 with 0.11 microM followed by DHB for CYP2C9 with 1.58 microM. PMID:17995595

  3. Profound reduction in the tamoxifen active metabolite endoxifen in a patient on phenytoin for epilepsy compared with a CYP2D6 genotype matched cohort.

    PubMed

    Gryn, Steven E; Teft, Wendy A; Kim, Richard B

    2014-07-01

    Tamoxifen is a prodrug, requiring cytochrome P450 enzyme-mediated metabolism to form the active metabolite endoxifen. We identified a case of drug-drug interaction involving tamoxifen and phenytoin, associated with a markedly lower endoxifen level than predicted. The patient is a 49-year-old woman, genotyped as a cytochrome P450 2D6 (CYP2D6) extensive metabolizer, chronically taking phenytoin for a seizure disorder. The plasma endoxifen level 2 months after starting tamoxifen was 4.72 nmol/l, the lowest level we have seen in our clinic among patients with CYP2D6 extensive metabolizer genotypes (n=195). To our knowledge, this is the first report documenting the extent of induction in terms of both tamoxifen and endoxifen levels during concomitant phenytoin therapy, and this effect would likely result in loss of therapeutic benefit from tamoxifen. Phenytoin should therefore not be used concurrently with tamoxifen for extended periods of time unless a therapeutic drug (endoxifen) monitoring strategy is utilized. PMID:24915025

  4. Population pharmacokinetics of nortriptyline during monotherapy and during concomitant treatment with drugs that inhibit CYP2D6--an evaluation with the nonparametric maximum likelihood method.

    PubMed Central

    Jerling, M; Merlé, Y; Mentré, F; Mallet, A

    1994-01-01

    Therapeutic drug monitoring data for nortriptyline (674 analyses from 578 patients) were evaluated with the nonparametric maximum likelihood (NPML) method in order to determine the population kinetic parameters of this drug and their relation to age, body weight and duration of treatment. Clearance of nortriptyline during monotherapy exhibited a large interindividual variability and a skewed distribution. A small, separate fraction with a very high clearance, constituting between 0.5% and 2% of the population, was seen in both men and women. This may be explained by the recent discovery of subjects with multiple copies of the gene encoding the cytochrome-P450-enzyme CYP2D6, which catalyses the hydroxylation of nortriptyline. However, erratic compliance with the prescription may also add to this finding. A separate distribution of low clearance values with a frequency corresponding to that of poor metabolizers of CYP2D6 (circa 7% in Caucasian populations) could not be detected. Concomitant therapy with drugs that inhibit CYP2D6 resulted in a major increase in the plasma nortriptyline concentrations. This was caused by a decrease in nortriptyline clearance, whereas the volume of distribution was unchanged. The demographic factors age and body weight had a minor influence on the clearance of nortriptyline which was also unaffected by the duration of treatment. PMID:7893588

  5. In vitro inhibition of human CYP1A2, CYP2D6, and CYP3A4 by six herbs commonly used in pregnancy.

    PubMed

    Langhammer, Astrid Jordet; Nilsen, Odd Georg

    2014-04-01

    Black elderberry, cranberry, fennel, ginger, horsetail, and raspberry leaf, herbs frequently used in pregnancy, were investigated for their in vitro CYP1A2, 2D6, and 3A4 inhibitory potential. Aqueous or ethanolic extracts were made from commercially available herbal products, and incubations were performed with recombinant cDNA-expressed human CYP enzymes in the presence of positive inhibitory controls. Metabolite formation was determined by validated LCMS/MS or HPLC methodologies. IC50 inhibition constants were estimated from CYP activity inhibition plots using non-linear regression. The most potent inhibition was shown for fennel towards CYP2D6 and 3A4 with respective IC50 constants of 23 ± 2 and 40 ± 4 µg/ml, horsetail towards CYP1A2 with an IC50 constant of 27 ± 1 µg/ml, and raspberry leaf towards CYP1A2, 2D6, and 3A4 with IC50 constants of 44 ± 2, 47 ± 8, and 81 ± 11 µg/ml, respectively. Based on the recommended dosing of the different commercial herbal products, clinically relevant systemic CYP inhibitions could be possible for fennel, horsetail, and raspberry leaf. In addition, fennel and raspberry leaf might cause a clinically relevant inhibition of intestinal CYP3A4. The in vivo inhibitory potential of these herbs towards specific CYP enzymes should be further investigated. PMID:23843424

  6. Influence of ABCB1 genetic polymorphisms on the pharmacokinetics of risperidone in healthy subjects with CYP2D6*10/*10

    PubMed Central

    Yoo, Hee-Doo; Lee, Sang-No; Kang, Hyun-Ah; Cho, Hea-Young; Lee, Il-Kwon; Lee, Yong-Bok

    2011-01-01

    BACKGROUND AND PURPOSE The objective of this study was to investigate the combined influence of genetic polymorphisms in ABCB1 and CYP2D6 genes on risperidone pharmacokinetics. EXPERIMENTAL APPROACH Seventy-two healthy Korean volunteers receiving a single oral dose of 2 mg risperidone were included in this study. KEY RESULTS Significant differences were observed between the ABCB1 3435C>T genotypes for the pharmacokinetic parameters (peak serum concentration) of risperidone and the active moiety (risperidone and its main metabolite, 9-hydroxyrisperidone). There were no significant differences in the area under the serum concentration-time curves of risperidone and the active moiety among the ABCB1 2677G>T/A and 3435C>T genotypes. However, the peak serum concentration and area under the serum concentration-time curves were significantly different among the ABCB1 3435C>T genotypes in CYP2D6*10/*10. CONCLUSIONS AND IMPLICATIONS These findings indicate that polymorphisms of ABCB1 3435C>T in individuals with CYP2D6*10/*10, which has low metabolic activity, could play an important role in the potential adverse effects or toxicity of risperidone. PMID:21449914

  7. Active sites of two orthologous cytochromes P450 2E1: Differences revealed by spectroscopic methods

    SciTech Connect

    Anzenbacherova, Eva; Hudecek, Jiri; Murgida, Daniel; Hildebrandt, Peter; Marchal, Stephane; Lange, Reinhard; Anzenbacher, Pavel . E-mail: anzen@tunw.upol.cz

    2005-12-09

    Cytochromes P450 2E1 of human and minipig origin were examined by absorption spectroscopy under high hydrostatic pressure and by resonance Raman spectroscopy. Human enzyme tends to denature to the P420 form more easily than the minipig form; moreover, the apparent compressibility of the heme active site (as judged from a redshift of the absorption maximum with pressure) is greater than that of the minipig counterpart. Relative compactness of the minipig enzyme is also seen in the Raman spectra, where the presence of planar heme conformation was inferred from band positions characteristic of the low-spin heme with high degree of symmetry. In this respect, the CYP2E1 seems to be another example of P450 conformational heterogeneity as shown, e.g., by Davydov et al. for CYP3A4 [Biochem. Biophys. Res. Commun. 312 (2003) 121-130]. The results indicate that the flexibility of the CYP active site is likely one of its basic structural characteristics.

  8. Bax inhibitor 1 regulates ER-stress-induced ROS accumulation through the regulation of cytochrome P450 2E1.

    PubMed

    Kim, Hyung-Ryong; Lee, Geum-Hwa; Cho, Eun Yi; Chae, Soo-Wan; Ahn, Taeho; Chae, Han-Jung

    2009-04-15

    This study investigated the molecular mechanism by which Bax inhibitor 1 (BI1) abrogates the accumulation of reactive oxygen species (ROS) in the endoplasmic reticulum (ER). Electron uncoupling between NADPH-dependent cytochrome P450 reductase (NPR) and cytochrome P450 2E1 (P450 2E1) is a major source of ROS on the ER membrane. ER stress produced ROS accumulation and lipid peroxidation of the ER membrane, but BI1 reduced this accumulation. Under ER stress, expression of P450 2E1 in control cells was upregulated more than in BI1-overexpressing cells. In control cells, inhibiting P450 2E1 through chemical or siRNA approaches suppressed ROS accumulation, ER membrane lipid peroxidation and the resultant cell death after ER stress. However, it had little effect in BI1-overexpressing cells. In addition, BI1 knock down also increased ROS accumulation and expression of P450 2E1. In a reconstituted phospholipid membrane containing purified BI1, NPR and P450 2E1, BI1 dose-dependently decreased the production of ROS. BI1 bound to NPR with higher affinity than P450 2E1. Furthermore, BI1 overexpression reduced the interaction of NPR and P450 2E1, and decreased the catalytic activity of P450 2E1, suggesting that the flow of electrons from NPR to P450 2E1 can be modulated by BI1. In summary, BI1 reduces the accumulation of ROS and the resultant cell death through regulating P450 2E1. PMID:19339548

  9. RORα switches transcriptional mode of ERRγ that results in transcriptional repression of CYP2E1 under ethanol-exposure

    PubMed Central

    Han, Yong-Hyun; Kim, Don-Kyu; Na, Tae-Young; Ka, Na-Lee; Choi, Hueng-Sik; Lee, Mi-Ock

    2016-01-01

    Increased cytochrome P450 2E1 (CYP2E1) expression is the main cause of oxidative stress, which exacerbates alcoholic liver diseases (ALDs). Estrogen-related receptor gamma (ERRγ) induces CYP2E1 expression and contributes to enhancing alcohol-induced liver injury. Retinoic acid-related orphan receptor alpha (RORα) has antioxidative functions; however, potential cross-talk between ERRγ and RORα in the regulation of CYP2E1 has not been studied. We report that RORα suppressed ERRγ-mediated CYP2E1 expression. A physical interaction of RORα with ERRγ at the ERRγ−response element in the CYP2E1 promoter was critical in this suppression. At this site, coregulator recruitment of ERRγ was switched from coactivator p300 to the nuclear receptor corepressor 1 in the presence of RORα. Cross-talk between ERRγ and RORα was demonstrated in vivo, in that administration of JC1–40, a RORα activator, significantly decreased both CYP2E1 expression and the signs of liver injury in ethanol-fed mice, and this was accompanied by coregulator switching. Thus, this non-classical RORα pathway switched the transcriptional mode of ERRγ, leading to repression of alcohol-induced CYP2E1 expression, and this finding may provide a new therapeutic strategy against ALDs. PMID:26464440

  10. CYP2E1 impairs GLUT4 gene expression and function: NRF2 as a possible mediator.

    PubMed

    Armoni, M; Harel, C; Ramdas, M; Karnieli, E

    2014-06-01

    Impaired GLUT4 function/expression in insulin target tissues is well-documented in diabetes and obesity. Cytochrome P450 isoform 2E1 (CYP2E1) induces oxidative stress, leading to impaired insulin action. CYP2E1 knockout mice are protected against high fat diet-induced insulin resistance and obesity; however the molecular mechanisms are still unclear. We examined whether CYP2E1 impairs GLUT4 gene expression and function in adipose and muscle cells. CYP2E1 overexpression in skeletal muscle-derived L6 cells inhibited insulin-stimulated Glut4 translocation and 2-deoxyglucose uptake, with the latter inhibition being blocked by vitamin E. CYP2E1 overexpression in L6 and primary rat adipose (PRA) cells suppressed GLUT4 gene expression at promoter and mRNA levels, whereas CYP2E1 silencing had opposite effects. In PRA, CYP2E1-induced suppression of GLUT4 expression was blocked by chlormethiazole (CYP2E1-specific inhibitor) and the antioxidants vitamin E and N-acetyl-l-cysteine. CYP2E1 effect was mediated by the transcription factor NF-E2-related factor 2 (NRF2), as evident from its complete reversal by a coexpressed dominant-negative, but not wild-type NRF2. GLUT4 transcription was suppressed by NRF2 overexpression, and enhanced by NRF2 silencing. Promoter and ChIP analysis showed a direct and specific binding of NRF2 to a 58-326 GLUT4 promoter region that was required to maintain CYP2E1 suppression; this binding was enhanced by CYP2E1 overexpression. We suggest a mechanism for CYP2E1 action that involves: a) suppression of GLUT4 gene expression that is mediated by NRF2; b) impairment of insulin-stimulated Glut4 translocation and function. CYP2E1 and NRF2 are introduced as negative regulators of GLUT4 expression and function in insulin-sensitive cells. PMID:24500986

  11. 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

  12. The Equine Herpesvirus 2 E1 Open Reading Frame Encodes a Functional Chemokine Receptor

    PubMed Central

    Camarda, Grazia; Spinetti, Gaia; Bernardini, Giovanni; Mair, Catherine; Davis-Poynter, Nick; Capogrossi, Maurizio C.; Napolitano, Monica

    1999-01-01

    Several herpesviruses contain open reading frames (ORFs) that encode potential homologs of eucaryotic genes. Equine herpesvirus 2 (EHV-2) is a gammaherpesvirus related to other lymphotropic herpesviruses such as herpesvirus saimiri and Epstein-Barr virus. The E1 ORF of EHV-2, a G protein-coupled receptor homolog, shows 31 to 47% amino acid identity with known CC chemokine receptors. To investigate whether E1 may encode a functional receptor, we cloned the E1 ORF and expressed it in stably transfected cell lines. We report here the identification of the CC chemokine eotaxin as a functional ligand for the EHV-2 E1 receptor. Chemokines are likely to play a role in the regulation of immune functions in equine hosts during EHV-2 infection and, via interaction with E1, may affect viral replication and/or escape from immune responses. PMID:10559296

  13. 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

  14. 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

  15. 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

  16. 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

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

    PubMed

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

    2015-03-01

    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

  18. The regulation of cytochrome P450 2E1 during LPS-induced inflammation in the rat

    SciTech Connect

    Abdulla, Dalya; Goralski, Kerry B.; Renton, Kenneth W. . E-mail: Ken.Renton@dal.ca

    2006-10-01

    It is well known that inflammatory and infectious conditions differentially regulate cytochrome P450 (P450)-mediated drug metabolism in the liver. We have previously outlined a potential pathway for the downregulation in hepatic cytochrome P450 following LPS-mediated inflammation in the CNS (Abdulla, D., Goralski, K.B., Garcia Del Busto Cano, E., Renton, K.W., 2005. The signal transduction pathways involved in hepatic cytochrome P450 regulation in the rat during an LPS-induced model of CNS inflammation. Drug Metab. Dispos). The purpose of this study was to outline the effects of LPS-induced peripheral and central nervous system inflammation on hepatic cytochrome P450 2E1 (CYP2E1) in vivo, an enzyme that plays an important role in various physiological and pathological states. We report an increase in hepatic mRNA expression of CYP2E1 that occurred as early as 2-3 h following either the intraperitoneal (i.p.) injection of 5 mg/kg LPS or i.c.v. administration of 25 {mu}g of LPS. This increase in CYP2E1 mRNA expression was sustained for 24 h. In sharp contrast to the increase in hepatic CYP2E1 mRNA, we observed a significant reduction in the catalytic activity of this enzyme 24 h following either the i.c.v. or i.p. administration of LPS. Cycloheximide or actinomycin-D did not change the LPS-mediated downregulation in hepatic CYP2E1 catalytic activity. Our results support the idea that LPS acts at two different levels to regulate hepatic CYP2E1: a transcriptional level to increase CYP2E1 mRNA expression and a post-transcriptional level to regulate CYP2E1 protein and activity.

  19. 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

  20. Development of a V79 cell line expressing human cytochrome P450 2D6 and its application as a metabolic screening tool.

    PubMed

    Rauschenbach, R; Gieschen, H; Salomon, B; Kraus, C; Kühne, G; Hildebrand, M

    1997-02-15

    Expression of human cytochrome P450 (CYP) in heterologous cells is a means of specifically studying the role of these enzymes in drug metabolism. The complete cDNA encoding CYP2D6-VAL(374) was inserted into an expression vector containing the strong mycloproliferative sarcoma virus promotor in combination with the enhancer of the cytomegalovirus and stably expressed in V79 Chinese hamster cells. The presence of genomically integrated CYP2D6 cDNA was confirmed by polymerase chain reaction analysis. The protein expression was shown by Western blotting. Functional expression could be demonstrated by O-demethylation of dextromethorphan to dextrorphan in live cells. The enzymatic activity of 154 ± 16 pmol min(-1) mg(-1) protein was comparable with dextromethorphan-O-demethylation activities of human liver. The metabolism of two dopaminergic ergoline derivatives was investigated in whole recombinant V19 cells. Both lisuride and terguride were monodeethylated; in case of lisuride a correlation to the in vivo situation was demonstrated comparing poor and extensive metabolizers. PMID:21781755

  1. Activity of immobilised rat hepatic microsomal CYP2E1 using alumina membrane as a support.

    PubMed

    Tanvir, Shazia; Morandat, Sandrine; Frederic, Nadaud; Adenier, Hervé; Pulvin, Sylviane

    2009-11-30

    Porous alumina membranes are attractive materials for the construction of biosensors and also have utility for the production of immobilised enzyme bioreactors. Microsomes from rat liver were adsorbed onto alumina membrane activated by silane. Microsomal membranes were pumped through the channels where they became immobilised by binding to amine groups on the surface of the alumina membrane. In an effort to gain a quantitative understanding of the effects of microsomal film growth on enzyme activity, we compared the para-nitrophenol (pNP) hydroxylase activity of the microsomes by varying the amount of microsomes fixed in alumina microchannels. The alumina membrane was placed in a fluidic device at a fast flow that afforded short residence time (seconds) to obtain transformation of pNP to 4-nitrocatechol (pNC), which was detected by LC-MS/MS. This enabled the use of this bioreactor where CYP2E1 activity is low and tissue sources are limiting. The microsomes, successfully immobilised on the alumina membranes, were used to produce stable biocatalytic reactors that can be used repeatedly over a period of 2 months. PMID:19703600

  2. Enhanced metabolism of halogenated hydrocarbons in transgenic plants containing mammalian cytochrome P450 2E1

    PubMed Central

    Doty, Sharon Lafferty; Shang, Tanya Q.; Wilson, Angela M.; Tangen, Jeff; Westergreen, Aram D.; Newman, Lee A.; Strand, Stuart E.; Gordon, Milton P.

    2000-01-01

    Chlorinated solvents, especially trichloroethylene (TCE), are the most widespread groundwater contaminants in the United States. Existing methods of pumping and treating are expensive and laborious. Phytoremediation, the use of plants for remediation of soil and groundwater pollution, is less expensive and has low maintenance; however, it requires large land areas and there are a limited number of suitable plants that are known to combine adaptation to a particular environment with efficient metabolism of the contaminant. In this work, we have engineered plants with a profound increase in metabolism of the most common contaminant, TCE, by introducing the mammalian cytochrome P450 2E1. This enzyme oxidizes a wide range of important pollutants, including TCE, ethylene dibromide, carbon tetrachloride, chloroform, and vinyl chloride. The transgenic plants had a dramatic enhancement in metabolism of TCE of up to 640-fold as compared with null vector control plants. The transgenic plants also showed an increased uptake and debromination of ethylene dibromide. Therefore, transgenic plants with this enzyme could be used for more efficient remediation of many sites contaminated with halogenated hydrocarbons. PMID:10841534

  3. Type II ligands as chemical auxiliaries to favor enzymatic transformations by P450 2E1.

    PubMed

    Ménard, Amélie; Fabra, Camilo; Huang, Yue; Auclair, Karine

    2012-11-26

    The remarkable ability of P450 enzymes to oxidize inactivated C-H bonds and the high substrate promiscuity of many P450 isoforms have inspired us and others to investigate their use as biocatalysts. Our lab has pioneered a chemical-auxiliary approach to control the promiscuity of P450 3A4 and provide product predictability. The recent realization that type II ligands are sometimes also P450 substrates has prompted the design of a new generation of chemical auxiliaries with type II binding properties. This approach takes advantage of the high affinity of type II ligands for the active site of these enzymes. Although type II ligands typically block P450 activity, we report here that type II ligation can be harnessed to achieve just the opposite, that is, to favor biocatalysis and afford predictable oxidation of small hydrocarbon substrates with P450 2E1. Moreover, the observed predictability was rationalized by molecular docking. We hope that this approach might find future use with other P450 isoforms and yield complimentary products. PMID:23129539

  4. Genetic mapping of a major site of phosphorylation in adenovirus type 2 E1A proteins

    SciTech Connect

    Tsukamotot, A.S.; Ponticelli, A.; Berk, A.J.; Gaynor, R.B.

    1986-07-01

    Adenovirus early region 1A (E1A) encodes two acidic phosphoproteins which are required for transactivation of viral transcription, efficient viral DNA replication in phase G/sub 0/-arrested human cells, and oncogenic transformation of rodent cells. Biochemical analysis of in vivo /sup 32/P-labeled adenovirus type 2 E1A proteins purified with monoclonal antibodies demonstrated that these proteins were phosphorylated at multiple serine residues. Two-dimensional phosphotryptic peptide maps of wild-type and mutant E1A proteins were used to locate a major site of E1A protein phosphorylation at serine-219 of the large E1A protein. Although this serine fell within a consensus sequence for phosphorylation by the cyclic AMP-dependent protein kinases, experiments with mutant CHO cells defective in these enzymes indicated that it was not. Oligonucleotide-directed mutagenesis was used to substitute an alanine for serine-219. This mutation prevented phosphorylation at this site. Nonetheless, the mutant was indistinguishable from the wild type for early gene transactivation, replication on G/sub 0/-arrested WI-38 cells, and transformation of cloned rat embryo fibroblast cells.

  5. CYP2E1 epigenetic regulation in chronic, low-level toluene exposure: Relationship with oxidative stress and smoking habit

    SciTech Connect

    Jiménez-Garza, Octavio; Baccarelli, Andrea A.; Byun, Hyang-Min; Márquez-Gamiño, Sergio; Barrón-Vivanco, Briscia Socorro

    2015-08-01

    Background: CYP2E1 is a versatile phase I drug-metabolizing enzyme responsible for the biotransformation of most volatile organic compounds, including toluene. Human toluene exposure increases CYP2E1 mRNA and modifies its activity in leucocytes; however, epigenetic implications of this interaction have not been investigated. Goal: To determine promoter methylation of CYP2E1 and other genes known to be affected by toluene exposure. Methods: We obtained venous blood from 24 tannery workers exposed to toluene (mean levels: 10.86 +/− 7 mg/m{sup 3}) and 24 administrative workers (reference group, mean levels 0.21 +/− 0.02 mg/m{sup 3}) all of them from the city of León, Guanajuato, México. After DNA extraction and bisulfite treatment, we performed PCR-pyrosequencing in order to measure methylation levels at promoter region of 13 genes. Results: In exposed group we found significant correlations between toluene airborne levels and CYP2E1 promoter methylation (r = − .36, p < 0.05), as well as for IL6 promoter methylation levels (r = .44, p < 0.05). Moreover, CYP2E1 promoter methylation levels where higher in toluene-exposed smokers compared to nonsmokers (p = 0.009). We also observed significant correlations for CYP2E1 promoter methylation with GSTP1 and SOD1 promoter methylation levels (r = − .37, p < 0.05 and r = − .34, p < 0.05 respectively). Conclusion: These results highlight the importance of considering CYP2E1 epigenetic modifications, as well as its interactions with other genes, as key factors for unraveling the sub cellular mechanisms of toxicity exerted by oxidative stress, which can initiate disease process in chronic, low-level toluene exposure. People co-exposed to toluene and tobacco smoke are in higher risk due to a possible CYP2E1 repression. - Highlights: • We investigated gene-specific methylation in persons chronically exposed to toluene. • In a previous study, a reduced CYP2E1 activity was observed in these participants. • CYP2E1

  6. Steady-state pharmacokinetics of the enantiomers of perhexiline in CYP2D6 poor and extensive metabolizers administered Rac-perhexiline

    PubMed Central

    Davies, Benjamin J; Herbert, Megan K; Coller, Janet K; Somogyi, Andrew A; Milne, Robert W; Sallustio, Benedetta C

    2008-01-01

    Aims To determine the steady-state pharmacokinetics of perhexiline (PHX) enantiomers over one interdosing interval in CYP2D6 extensive and poor metabolizer (EM and PM, respectively) patients administered rac-PHX. To elucidate the processes responsible for enantioselectivity, particularly in PM patients. Methods Blood samples were taken over one interdosing interval from six EM and two PM patients at steady-state with respect to rac-PHX metabolism. Complete urine collections were taken from five EM patients. PHX concentrations in plasma and urine were determined with enantioselective high-performance liquid chromatography methods. Results EM patients had 16- and 10-fold greater median apparent oral clearances of (+)- and (−)-PHX, respectively, than PM patients (P < 0.05 for both) and required significantly larger doses of rac-PHX (69 vs. 4.2 µg kg−1 h−1, P < 0.05) to maintain therapeutic concentrations in plasma. Patient phenotypes were consistent with CYP2D6 genotypes. Both groups displayed enantioselective pharmacokinetics, with higher apparent oral clearances for (−)-PHX compared with (+)-PHX, although PM patients exhibited significantly greater enantioselectivity (P < 0.05). The renal clearance of PHX enantiomers was not enantioselective and accounted for <1% of the median apparent oral clearance of each enantiomer in EM patients. Assuming the same renal clearances for PM patients accounts for approximately 9 and 4% of their median apparent oral clearances of (+)- and (−)-PHX, respectively. Conclusions The enantioselective pharmacokinetics of PHX are primarily due to metabolism by CYP2D6 in EM patients. The mechanism responsible for the enantioselective pharmacokinetics of PHX in PM patients is unknown, but may be due to enantioselective biliary or intestinal excretion. What is already known about this subject Perhexiline (PHX) is administered as a racemic mixture and exhibits enantioselective pharmacokinetics in both poor and extensive metabolizers

  7. Human CYP2E1-dependent mutagenicity of mono- and dichlorobiphenyls in Chinese hamster (V79)-derived cells.

    PubMed

    Zhang, Chiteng; Lai, Yanmei; Jin, Guifang; Glatt, Hansruedi; Wei, Qinzhi; Liu, Yungang

    2016-02-01

    Polychlorinated biphenyls (PCBs) are a group of persistent organic pollutants with confirmed carcinogenicity to humans. Metabolic activation of lower chlorinated PCBs to genotoxic metabolites may involve hydroxylation and further oxidation, and some hydroxylated metabolites may be sulfo-conjugated. However, the genotoxicity of individual PCB compounds is largely unknown. In this study, 15 mono- and dichlorobiphenyls were investigated for genotoxicity using the micronucleus and Hprt mutagenicity assays in a Chinese hamster V79-derived cell line expressing both human cytochrome P450 (CYP) 2E1 and human sulfotransferase (SULT) 1A1 (V79-hCYP2E1-hSULT1A1). All tested compounds were inactive in both assays in V79 control cells. However, eight dichlorobiphenyls strongly induced micronuclei and other congeners were weakly positive for this endpoint in V79-hCYP2E1-hSULT1A1 cells. The effects of each PCB in V79-hCYP2E1-hSULT1A1 cells were abolished or reduced in the presence of a CYP2E1 inhibitor (1-aminobenzotriazole), or enhanced by pretreatment of the cells with (CYP2E1-inducing) ethanol, while the genotoxicity was not significantly affected by a SULT1 inhibitor (pentachlorophenol). As representative dichlorobiphenyls, PCB 5, 10, 8 and 11 (2,3-, 2,5-, 2,4'- and 3,3'-dichlorobiphenyl, respectively) strongly induced Hprt gene mutations in V79-hCYP2E1-hSULT1A1 cells in a concentration-dependent manner. This is the first indication that human CYP2E1 is capable of converting a series of dichlorobiphenyls to strong mutagens. PMID:26547025

  8. 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

  9. 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

  10. Further characterization of a ¹³C-dextromethorphan breath test for CYP2D6 phenotyping in breast cancer patients on tamoxifen therapy.

    PubMed

    Opdam, F L; Modak, A S; Gelderblom, H; Guchelaar, H J

    2015-06-01

    In a previous study, we found that the CYP2D6 phenotype determined by (13)C-dextromethorphan breath test (DM-BT) might be used to predict tamoxifen treatment outcome in breast cancer patients in the adjuvant setting. However, large variation in the delta-over-baseline (DOB) values was observed in the extensive metabolizer predicted phenotype group based on single point measures. In the present work we aimed to analyze the variability of phenotype results and determine reproducibility to further characterize the clinical utility of DM-BT by introducing multiple breath sampling instead of single breath sampling and by administration of a fixed dose of (13)C-DM. PMID:25891764

  11. 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.

  12. Impact of Tetrahydropalmatine on the Pharmacokinetics of Probe Drugs for CYP1A2, 2D6 and 3A Isoenzymes in Beagle Dogs.

    PubMed

    Zhao, Yong; Liang, Aihua; Zhang, Yushi; Li, Chunying; Yi, Yan; Nilsen, Odd Georg

    2016-06-01

    Tetrahydropalmatine (Tet) exhibit multiple pharmacological activities and is used frequently by clinical practitioners. In this study, we evaluate the in vivo effects of single and repeated oral Tet administrations on CYP1A2, 2D6 and 3A activities in six beagle dogs in a randomized, controlled, open-label, crossover study. A cocktail approach, with dosages of the probe drugs caffeine (3.0 mg/kg), metoprolol (2.33 mg/kg) and midazolam (0.45 mg/kg), was used to measure cytochrome P450 (CYP) metabolic activities. The cocktail was administered orally as a single dose (12 mg/kg) 1 day prior to and 4 days after repeated oral Tet administrations (12 mg/kg three times daily). The probe drugs and their metabolites in plasma were quantified simultaneously by a validated HPLC technique, and non-compartmental parameters were used to evaluate metabolic variables for assessment of CYP inhibition or induction. Tet had no or minor impact on the pharmacokinetics and metabolism of the probe drugs caffeine and metoprolol, CYP1A2 and CYP2D6 substrates, respectively. However, Tet increased AUC0-24 h and decreased AUCratio(0-24 h) (1-hydroxymidazolam/midazolam ratio) for midazolam statistically significant, both in single or multiple dosing of Tet, with up to 39 or 57% increase for AUC0-24 h and 29% or 22 decrease for AUCratio(0-24 h), respectively, in line with previous in vitro findings for its CYP3A4 inhibition. The extensive use of Tet and herbal medicines containing Tet makes Tet a candidate for further evaluation of CYP3A-mediated herb-drug interactions. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26990021

  13. CYP2E1 gene rs6413420 polymorphism was first found in the Bouyei ethnic group of China

    PubMed Central

    Liu, Wei; Zhou, Li; Wang, Hongju; Zheng, Bo; Wu, Desheng; Yang, Xifei; Liu, Jianjun

    2014-01-01

    Background: China is a multinational country. The relationship between gene polymorphisms of xenobiotic metabolizing enzymes and national ethnicity has not previously investigated among Chinese people. The aim of this study was to investigate distributions of CYP1A1 and CYP2E1 gene polymorphisms in five ethnic groups of China. Methods: 829 blood samples were collected from five ethnic groups (Han, Shui, Miao, Zhuang, Bouyei). Taqman-MGB probe was used in Real-time PCR to test the gene polymorphisms of CYP1A1 (rs1048943 and rs4646903) and CYP2E1 (rs2031920 and rs6413420). We further validate the SNP genotyping results through DNA sequencing. Results: The genotype distribution of all four SNPs was in accordance with Hardy-Weinberg equilibrium except the genotype distribution of rs4646903 in Han and Bouyei ethnic groups (p=0.013 and 0.0005, respectively). CYP2E1 gene rs6413420 polymorphism was first found in the Bouyei ethnic group in China. The results of DNA sequencing were entirely in line with the SNP genotyping assay. Conclusions: The CYP1A1 and CYP2E1 genetic polymorphisms were different in different ethnic groups in China. CYP2E1 gene rs6413420 polymorphism was first found in the Bouyei ethnic group of China. PMID:25419409

  14. Tetra Primer ARMS PCR Optimization to Detect Single Nucleotide Polymorphisms of the CYP2E1 Gene.

    PubMed

    Suhda, Saihas; Paramita, Dewi Kartikawati; Fachiroh, Jajah

    2016-01-01

    Single nucleotide polymorphism (SNP) detection has been used extensively for genetic association studies of diseases including cancer. For mass, yet accurate and more economic SNP detection we have optimized tetra primer amplification refractory mutation system polymerase chain reaction (ARMS PCR) to detect three SNPs in the cytochrome P450 2E1 (CYP2E1) gene locus; i.e. rs3813865, rs2070672 and rs3813867. The optimization system strategies used were (1) designing inner and outer primers; (2) determining of their optimum primer concentration ratios; and (3) determining of the optimum PCR annealing temperature. The tetra primer ARMS PCR result could be directly observed using agarose gel electrophoresis. The method succesfully determined three SNPs in CYP2E1 locus, the results being consistent with validation using DNA sequencing and restriction fragment length polymorphisms (RFLP). PMID:27509930

  15. Identification of inhibitory component in cinnamon--O-methoxycinnamaldehyde inhibits CYP1A2 and CYP2E1-.

    PubMed

    Hasegawa, Atsushi; Yoshino, Masaki; Nakamura, Hiroyoshi; Ishii, Itsuko; Watanabe, Toshiko; Kiuchi, Masahiro; Ishikawa, Tsutomu; Ohmori, Shigeru; Kitada, Mitsukazu

    2002-01-01

    The Cinnamomi Cortex and Ephedra Herba were found to more strongly inhibit aminopyrine N-demethylation in rat liver microsomes compared to other constituents included in Sho-seiryu-to. The component inhibiting drug oxidations catalyzed by CYP1A2 and CYP2E1 was isolated from Cinnamomi Cortex, and was identified as o-methoxycinnamaldehyde (OMCA). When phenacetin and 4-nitrophenol were used as probe substrates for CYP1A2 and CYP2E1, respectively, the OMCA was shown to be a competitive inhibitor against CYP1A2 while it was a mixed type inhibitor against CYP2E1. The inhibitory effect of OMCA on 4-nitrophenol 2-hydroxylation (K(i)=6.3 microM) was somewhat potent compared to that observed on phenacetin O-deethylation (K(i)=13.7 microM) in rat liver microsomes. PMID:15618674

  16. Cytochrome P450 2E1 inhibition prevents hepatic carcinogenesis induced by diethylnitrosamine in alcohol-fed rats

    PubMed Central

    Ye, Qinyuan; Lian, Fuzhi; Chavez, Pollyanna R.G.; Chung, Jayong; Ling, Wenhua; Qin, Hua; Seitz, Helmut K.

    2012-01-01

    Chronic alcohol ingestion increases hepatic cytochrome P450 2E1 (CYP2E1), which is associated with hepatocarcinogenesis. We investigated whether treatment with chlormethiazole (CMZ), a CYP2E1 inhibitor, protects against alcohol-associated hepatic carcinogenesis in rats. Rats were fed either an ethanol liquid diet or a non-ethanol liquid diet, with or without CMZ for one and ten months. A single intraperitoneal injection of diethylnitrosamine (DEN, 20 mg/kg) was given to initiate hepatic carcinogenesis. CYP2E1 expression, inflammatory proteins, cell proliferation, protein-bound 4-HNE, etheno-DNA adducts, 8-hydroxy-2'-deoxyguanosine (8-OHdG), retinoid concentrations, and hepatic carcinogenesis were examined. Ethanol feeding for 1 month with DEN resulted in significantly increased hepatic CYP2E1 levels and increased nuclear accumulation of NF-κB protein and TNF-α expression, which were associated with increased cyclin D1 expression and p-GST positive altered hepatic foci. All of these changes induced by ethanol feeding were significantly inhibited by the one month CMZ treatment. At 10-months of treatment, hepatocellular adenomas were detected in ethanol-fed rats only, but neither in control rats nor in animals receiving ethanol and CMZ. The 8-OHdG formation was found to be significantly increased in ethanol fed animals and normalized with CMZ treatment. In addition, alcohol-reduced hepatic retinol and retinoic acid concentrations were restored by CMZ treatment to normal levels in the rats at 10 months of treatment. These data demonstrate that the inhibition of ethanol-induced CYP2E1 as a key pathogenic factor can counteract the tumor-promoting action of ethanol by decreasing TNF-α expression, NF-κB activation, and oxidative DNA damage as well as restoring normal hepatic levels of retinoic acid in DEN-treated rats. PMID:23543859

  17. Cytochrome P450-2E1 promotes aging-related hepatic steatosis, apoptosis and fibrosis through increased nitroxidative stress.

    PubMed

    Abdelmegeed, Mohamed A; Choi, Youngshim; Ha, Seung-Kwon; Song, Byoung-Joon

    2016-02-01

    The role of ethanol-inducible cytochrome P450-2E1 (CYP2E1) in promoting aging-dependent hepatic disease is unknown and thus was investigated in this study. Young (7 weeks) and aged female (16 months old) wild-type (WT) and Cyp2e1-null mice were used in this study to evaluate age-dependent changes in liver histology, steatosis, apoptosis, fibrosis and many nitroxidative stress parameters. Liver histology showed that aged WT mice exhibited markedly elevated hepatocyte vacuolation, ballooning degeneration, and inflammatory cell infiltration compared to all other groups. These changes were accompanied with significantly higher hepatic triglyceride and serum cholesterol in aged WT mice although serum ALT and insulin resistance were not significantly altered. Aged WT mice showed the highest rates of hepatocyte apoptosis and hepatic fibrosis. Further, the highest levels of hepatic hydrogen peroxide, lipid peroxidation, protein carbonylation, nitration, and oxidative DNA damage were observed in aged WT mice. These increases in the aged WT mice were accompanied by increased levels of mitochondrial nitroxidative stress and alteration of mitochondrial complex III and IV proteins in aged WT mice, although hepatic ATP levels seems to be unchanged. In contrast, the aging-related nitroxidative changes were very low in aged Cyp2e1-null mice. These results suggest that CYP2E1 is important in causing aging-dependent hepatic steatosis, apoptosis and fibrosis possibly through increasing nitroxidative stress and that CYP2E1 could be a potential target for translational research in preventing aging-related liver disease. PMID:26703967

  18. Cytochrome P450 2E1 inhibition prevents hepatic carcinogenesis induced by diethylnitrosamine in alcohol-fed rats.

    PubMed

    Ye, Qinyuan; Lian, Fuzhi; Chavez, Pollyanna R G; Chung, Jayong; Ling, Wenhua; Qin, Hua; Seitz, Helmut K; Wang, Xiang-Dong

    2012-12-01

    Chronic alcohol ingestion increases hepatic cytochrome P450 2E1 (CYP2E1), which is associated with hepatocarcinogenesis. We investigated whether treatment with chlormethiazole (CMZ), a CYP2E1 inhibitor, protects against alcohol-associated hepatic carcinogenesis in rats. Rats were fed either an ethanol liquid diet or a non-ethanol liquid diet, with or without CMZ for one and ten months. A single intraperitoneal injection of diethylnitrosamine (DEN, 20 mg/kg) was given to initiate hepatic carcinogenesis. CYP2E1 expression, inflammatory proteins, cell proliferation, protein-bound 4-HNE, etheno-DNA adducts, 8-hydroxy-2'-deoxyguanosine (8-OHdG), retinoid concentrations, and hepatic carcinogenesis were examined. Ethanol feeding for 1 month with DEN resulted in significantly increased hepatic CYP2E1 levels and increased nuclear accumulation of NF-κB protein and TNF-α expression, which were associated with increased cyclin D1 expression and p-GST positive altered hepatic foci. All of these changes induced by ethanol feeding were significantly inhibited by the one month CMZ treatment. At 10-months of treatment, hepatocellular adenomas were detected in ethanol-fed rats only, but neither in control rats nor in animals receiving ethanol and CMZ. The 8-OHdG formation was found to be significantly increased in ethanol fed animals and normalized with CMZ treatment. In addition, alcohol-reduced hepatic retinol and retinoic acid concentrations were restored by CMZ treatment to normal levels in the rats at 10 months of treatment. These data demonstrate that the inhibition of ethanol-induced CYP2E1 as a key pathogenic factor can counteract the tumor-promoting action of ethanol by decreasing TNF-α expression, NF-κB activation, and oxidative DNA damage as well as restoring normal hepatic levels of retinoic acid in DEN-treated rats. PMID:23543859

  19. Occupational Toluene Exposure Induces Cytochrome P450 2E1 mRNA Expression in Peripheral Lymphocytes

    PubMed Central

    Mendoza-Cantú, Ania; Castorena-Torres, Fabiola; de León, Mario Bermúdez; Cisneros, Bulmaro; López-Carrillo, Lizbeth; Rojas-García, Aurora E.; Aguilar-Salinas, Alberto; Manno, Maurizio; Albores, Arnulfo

    2006-01-01

    Print workers are exposed to organic solvents, of which the systemic toxicant toluene is a main component. Toluene induces expression of cytochrome P450 2E1 (CYP2E1), an enzyme involved in its own metabolism and that of other protoxicants, including some procarcinogens. Therefore, we investigated the association between toluene exposure and the CYP2E1 response, as assessed by mRNA content in peripheral lymphocytes or the 6-hydroxychlorzoxazone (6OH-CHZ)/chlorzoxazone (CHZ) quotient (known as CHZ metabolic ratio) in plasma, and the role of genotype (5′-flanking region RsaI/PstI polymorphic sites) in 97 male print workers. The geometric mean (GM) of toluene concentration in the air was 52.80 ppm (10–760 ppm); 54% of the study participants were exposed to toluene concentrations that exceeded the maximum permissible exposure level (MPEL). The GM of urinary hippuric acid at the end of a work shift (0.041 g/g creatinine) was elevated relative to that before the shift (0.027 g/g creatinine; p < 0.05). The GM of the CHZ metabolic ratio was 0.33 (0–9.3), with 40% of the subjects having ratios below the GM. However, the average CYP2E1 mRNA level in peripheral lymphocytes was 1.07 (0.30–3.08), and CYP2E1 mRNA levels within subjects correlated with the toluene exposure ratio (environmental toluene concentration:urinary hippuric acid concentration) (p = 0.014). Genotype did not alter the association between the toluene exposure ratio and mRNA content. In summary, with further validation, CYP2E1 mRNA content in peripheral lymphocytes could be a sensitive and noninvasive biomarker for the continuous monitoring of toluene effects in exposed persons. PMID:16581535

  20. Association of mitochondrial deoxyribonucleic acid mutation with polymorphism in CYP2E1 gene in oral carcinogenesis

    PubMed Central

    Pandey, Rahul; Mehrotra, Divya; Catapano, Carlo; Choubey, Vimal; Sarin, Rajiv; Mahdi, Abbas Ali; Singh, Stuti

    2012-01-01

    Background Oral carcinogenesis is a complex process affected by genetic as well as environmental factors. CYP2E1 gene is involved in metabolism of number of compounds and carcinogens. Its normal functioning is required for homeostasis of free radical. Mitochondrial deoxyribonucleic acid (mtDNA) is 10–100 times more susceptible to damage than nuclear DNA. Mitochondrial DNA large scale deletions are well documented in oral cancer. However, the relationship between CYP2E1 gene polymorphisms and mtDNA damage is still not documented in literature. Materials and Methods Case–control study involving 50 subjects was carried out. Deoxyribonucleic acid extraction was done from study subject tissue samples. Restriction fragment length polymorphism (RFLP) and polymerase chain reaction (PCR) amplification was done to confirm CYP2E1 gene polymorphisms. The PCR amplification was done for mtDNA 4977 bp deletion. Statistical analysis was carried out using SPSS version 11.5 with χ2 tests. Results c1c1 and DD polymorphisms are prevalent in North Indian population having oral cancer. These polymorphisms are significantly associated with mtDNA 4977 bp deletion. Conclusion Mitochondrial DNA damage induced by wild CYP2E1 forms and imperfect DNA repair in mtDNA may act synergistically to greatly enhance oral cancer risk. PMID:25756024

  1. Induction of CYP2E1 in testes of isoniazid-treated rats as possible cause of testicular disorders.

    PubMed

    Shayakhmetova, Ganna M; Bondarenko, Larysa B; Voronina, Alla K; Anisimova, Svitlana I; Matvienko, Anatoliy V; Kovalenko, Valentina M

    2015-04-16

    Isoniazid is reported to be the most reliable and cost-effective remedy for tuberculosis treatment and prophylaxis among first line anti-tuberculosis drugs. Conventionally, the most common and best studied adverse effect of isoniazid is hepatotoxicity, but as for testicular toxicity the problem has not yet explored extensively. The aim of the study was to identify in vivo influence of isoniazid on induction of testicular cytochrome Р-450 2Е1 (CYP2E1) mRNA expression and enzymatic activity, testes DNA fragmentation, serum total testosterone level, and spermatogenesis indices. The significant induction of CYP2E1 was demonstrated in rat's testes following isoniazid administration, specifically CYP2E1 mRNA expression and p-nitrophenolhydroxylase activity was increased in 28 and 7 times as compared with control, respectively. These changes were accompanied by activating of testicular GST in 32%, changing in levels and character of DNA fragmentation, as well as damaging of the spermatogenic epithelium, decreasing in serum testosterone content (1.62 fold), sperm count (19%), and losing of fertility in comparison with untreated males. We assume that in testes of isoniazid-treated rats CYP2E1 may act as a trigger in generating of reactive oxygen species and other toxic metabolites which subsequently mediates DNA damage, spermatogenesis disturbances, and altered male fertilizing capacity. PMID:25683034

  2. Effects of herbal products and their constituents on human cytochrome P450(2E1) activity.

    PubMed

    Raner, Gregory M; Cornelious, Sean; Moulick, Kamalika; Wang, Yingqing; Mortenson, Ashley; Cech, Nadja B

    2007-12-01

    Ethanolic extracts from fresh Echinacea purpurea and Spilanthes acmella and dried Hydrastis canadensis were examined with regard to their ability to inhibit cytochrome P450(2E1) mediated oxidation of p-nitrophenol in vitro. In addition, individual constituents of these extracts, including alkylamides from E. purpurea and S. acmella, caffeic acid derivatives from E. purpurea, and several of the major alkaloids from H. canadensis, were tested for inhibition using the same assay. H. canadensis (goldenseal) was a strong inhibitor of the P450(2E1), and the inhibition appeared to be related to the presence of the alkaloids berberine, hydrastine and canadine in the extract. These compounds inhibited 2E1 with K(I) values ranging from 2.8 microM for hydrastine to 18 microM for berberine. The alkylamides present in E. purpurea and S. acmella also showed significant inhibition at concentrations as low as 25 microM, whereas the caffeic acid derivatives had no effect. Commercial green tea preparations, along with four of the individual tea catechins, were also examined and were found to have no effect on the activity of P450(2E1). PMID:17658211

  3. Cytochrome P450 2E1 is responsible for the initiation of 1,2-dichloropropane-induced liver damage.

    PubMed

    Yanagiba, Yukie; Suzuki, Tetsuya; Suda, Megumi; Hojo, Rieko; Gonzalez, Frank J; Nakajima, Tamie; Wang, Rui-Sheng

    2016-09-01

    1,2-Dichloropropane (1,2-DCP), a solvent, which is the main component of the cleaner used in the offset printing companies in Japan, is suspected to be the causative agent of bile duct cancer, which has been recently reported at high incidence in those offset printing workplaces. While there are some reports about the acute toxicity of 1,2-DCP, no information about its metabolism related to toxicity in animals is available. As part of our efforts toward clarifying the role of 1,2-DCP in the development of cancer, we studied the metabolic pathways and the hepatotoxic effect of 1,2-DCP in mice with or without cytochrome P450 2E1 (CYP2E1) activity. In an in vitro reaction system containing liver homogenate, 1,2-DCP was only metabolized by liver tissue of wild-type mice but not by that of cyp2e1-null mice. Furthermore, the kinetics of the solvent in mice revealed a great difference between the two genotypes; 1,2-DCP administration resulted in dose-dependent hepatic damage, as shown biochemically and pathologically, but this effect was only observed in wild-type mice. The nuclear factor κB p52 pathway was involved in the liver response to 1,2-DCP. Our results clearly indicate that the oxidative metabolism of 1,2-DCP in mice is exclusively catalyzed by CYP2E1, and this step is indispensable for the manifestation of the hepatotoxic effect of the solvent. PMID:25681370

  4. Role of CYP2E1 and saturation kinetics in the bioactivation of thioacetamide: Effects of diet restriction and phenobarbital

    SciTech Connect

    Chilakapati, Jaya; Korrapati, Midhun C.; Shankar, Kartik; Hill, Ronald A.; Warbritton, Alan; Latendresse, John R.; Mehendale, Harihara M. . E-mail: mehendale@ulm.edu

    2007-02-15

    Thioacetamide (TA) undergoes saturation toxicokinetics in ad libitum (AL) fed rats. Diet restriction (DR) protects rats from lethal dose of TA despite increased bioactivation-mediated liver injury via CYP2E1 induction. While a low dose (50 mg TA/kg) produces 6-fold higher initial injury, a 12-fold higher dose produces delayed and mere 2.5-fold higher injury. The primary objective was to determine if this less-than-expected increase in injury is due to saturation toxicokinetics. Rats on AL and DR for 21 days received either 50 or 600 mg TA/kg i.p. T {sub 1/2} and AUCs for TA and TA-S-oxide were consistent with saturable kinetics. Covalent binding of {sup 14}C-TA-derived-radiolabel to liver macromolecules after low dose was 2-fold higher in DR than AL rats. However, following lethal dose, no differences were found between AL and DR. This lack of dose-dependent response appears to be due to saturation of bioactivation at the higher dose. The second objective was to investigate the effect of phenobarbital pretreatment (PB) on TA-initiated injury following a sub-lethal dose (500 mg/kg). PB induced CYP2B1/2 {approx} 350-fold, but did not increase covalent binding of {sup 14}C-TA, TA-induced liver injury and mortality, suggesting that CYP2B1/2 has no major role in TA bioactivation. The third objective was to investigate the role of CYP2E1 using cyp2e1 knockout mice (KO). Injury was assessed over time (0-48 h) in wild type (WT) and KO mice after LD{sub 100} dose (500 mg/kg) in WT. While WT mice exhibited robust injury which progressed to death, KO mice exhibited neither initiation nor progression of injury. These findings confirm that CYP2E1 is responsible for TA bioactivation.

  5. Role and importance of polymorphisms with respect to DNA methylation for the expression of CYP2E1 enzyme.

    PubMed

    Naselli, Flores; Catanzaro, Irene; Bellavia, Daniele; Perez, Alessandro; Sposito, Laura; Caradonna, Fabio

    2014-02-15

    Different individuals possess slightly different genetic information and show genetically-determined differences in several enzyme activities due to genetic variability. Following an integrated approach, we studied the polymorphisms and methylation of sites contained in the 5' flanking region of the metabolizing enzyme CYP2E1 in correlation to its expression in both tumor and non-neoplastic liver cell lines, since to date little is known about the influence of these (epi)genetic elements in basal conditions and under induction by the specific inductor and a demethylating agent. In treated cells, reduced DNA methylation, assessed both at genomic and gene level, was not consistently associated with the increase of enzyme expression. Interestingly, the Rsa/Pst haplotype differentially influenced CYP2E1 enzyme expression. In addition, regarding the Variable Number of Tandem Repeats polymorphism, cells with A4/A4 genotype showed a greater expression inhibition (ranging from 20% to 30%) compared with others carrying the A2/A2 one, while those cells bringing A2/A3 genotype showed an increase of expression (of 25%, about). Finally, we demonstrated for the first time that the A2 and A3 CYP2E1 alleles play a more important role in the expression of the enzyme, compared with other (epi)genetic factors, since they are binding sites for trans-acting proteins. PMID:24333271

  6. Global patterns of variation in allele and haplotype frequencies and linkage disequilibrium across the CYP2E1 gene

    PubMed Central

    Lee, Mi-Young; Mukherjee, Namita; Pakstis, Andrew J.; Khaliq, Shagufta; Mohyuddin, Aisha; Mehdi, S. Qasim; Speed, William C.; Kidd, Judith R.; Kidd, Kenneth K.

    2009-01-01

    Cytochrome P450 2E1, gene symbol CYP2E1, is one of a family of enzymes with a central role in activating and detoxifying xenobiotics and endogenous compounds. Genetic variation at this gene has been reported in different human populations, and some association studies have reported increased risk for cancers and other diseases. To the best of our knowledge, multi-SNP haplotypes and linkage disequilibrium (LD) have not been systematically studied for CYP2E1 in multiple populations. Haplotypes can greatly increase the power both to identify patterns of genetic variation relevant for gene expression as well as to detect disease-related susceptibility mutations. We present frequency and LD data and analyses for 11 polymorphisms and their haplotypes that we have studied on over 2,600 individuals from 50 human population samples representing the major geographical regions of the world. The diverse patterns of haplotype variation found in the different populations we have studied show that ethnicity may be an important variable helping to explain inconsistencies that have been reported by association studies. More studies clearly are needed of the variants we have studied, especially those in the 5′ region, such as the VNTR, as well as studies of additional polymorphisms known for this gene to establish evidence relating any systematic differences in gene expression that exist to the haplotypes at this gene. PMID:18663376

  7. Kinetics of cytochrome P450 2E1-catalyzed oxidation of ethanol to acetic acid via acetaldehyde.

    PubMed

    Bell-Parikh, L C; Guengerich, F P

    1999-08-20

    The P450 2E1-catalyzed oxidation of ethanol to acetaldehyde is characterized by a kinetic deuterium isotope effect that increases K(m) with no effect on k(cat), and rate-limiting product release has been proposed to account for the lack of an isotope effect on k(cat) (Bell, L. C., and Guengerich, F. P. (1997) J. Biol. Chem. 272, 29643-29651). Acetaldehyde is also a substrate for P450 2E1 oxidation to acetic acid, and k(cat)/K(m) for this reaction is at least 1 order of magnitude greater than that for ethanol oxidation to acetaldehyde. Acetic acid accounts for 90% of the products generated from ethanol in a 10-min reaction, and the contribution of this second oxidation has been overlooked in many previous studies. The noncompetitive intermolecular kinetic hydrogen isotope effects on acetaldehyde oxidation to acetic acid ((H)(k(cat)/K(m))/(D)(k(cat)/K(m)) = 4.5, and (D)k(cat) = 1.5) are comparable with the isotope effects typically observed for ethanol oxidation to acetaldehyde, and k(cat) is similar for both reactions, suggesting a possible common catalytic mechanism. Rapid quench kinetic experiments indicate that acetic acid is formed rapidly from added acetaldehyde (approximately 450 min(-1)) with burst kinetics. Pulse-chase experiments reveal that, at a subsaturating concentration of ethanol, approximately 90% of the acetaldehyde intermediate is directly converted to acetic acid without dissociation from the enzyme active site. Competition experiments suggest that P450 2E1 binds acetic acid and acetaldehyde with relatively high K(d) values, which preclude simple tight binding as an explanation for rate-limiting product release. The existence of a rate-determining step between product formation and release is postulated. Also proposed is a conformational change in P450 2E1 occurring during the course of oxidation and the discrimination of P450 2E1 between acetaldehyde and its hydrated form, the gem-diol. This multistep P450 reaction is characterized by kinetic

  8. Inhibition of human Cytochrome P450 2E1 and 2A6 by aldehydes: Structure and activity relationships

    PubMed Central

    Kandagatla, Suneel K.; Mack, Todd; Simpson, Sean; Sollenberger, Jill; Helton, Eric; Raner, Gregory M.

    2014-01-01

    The purpose of this study was to probe active site structure and dynamics of human cytochrome P4502E1 and P4502A6 using a series of related short chain fatty aldehydes. Binding efficiency of the aldehydes was monitored via their ability to inhibit the binding and activation of the probe substrates p-nitrophenol (2E1) and coumarin (2A6). Oxidation of the aldehydes was observed in reactions with individually expressed 2E1, but not 2A6, suggesting alternate binding modes. For saturated aldehydes the optimum chain length for inhibition of 2E1 was 9 carbons (KI=7.8 ±0.3 μM), whereas for 2A6 heptanal was most potent (KI=15.8 ±1.1 μM). A double bond in the 2-position of the aldehyde significantly decreased the observed KI relative to the corresponding saturated compound in most cases. A clear difference in the effect of the double bond was observed between the two isoforms. With 2E1, the double bond appeared to remove steric constraints on aldehyde binding with KI values for the 5–12 carbon compounds ranging between 2.6 ± 0.1 μM and 12.8± 0.5 μM, whereas steric effects remained the dominant factor in the binding of the unsaturated aldehydes to 2A6 (observed KI values between 7.0± 0.5 μM and >1000 μM). The aldehyde function was essential for effective inhibition, as the corresponding carboxylic acids had very little effect on enzyme activity over the same range of concentrations, and branching at the 3-position of the aldehydes increased the corresponding KI value in all cases examined. The results suggest that a conjugated π-system may be a key structural determinant in the binding of these compounds to both enzymes, and may also be an important feature for the expansion of the active site volume in 2E1. PMID:24924949

  9. 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

  10. 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

  11. 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

  12. Simultaneous genotyping of CYP2D6*3, *4, *5 and *6 polymorphisms in a Spanish population through multiplex long polymerase chain reaction and minisequencing multiplex single base extension analysis.

    PubMed

    Crescenti, A; Mas, S; Gassó, P; Baiget, M; Bernardo, M; Lafuente, A

    2007-10-01

    1. The aim of the present study was to perform a descriptive study of the prevalence of the four major CYP2D6 poor metaboliser (PM) alleles (*3, *4, *5 and *6) in a Spanish population (n = 290) using a method based on a new combination of multiplex long polymerase chain reaction (PCR) and minisequencing through multiplex single base extension (SBE) analysis. 2. The method was validated using different strategies, such as allelic discrimination assay and PCR-restriction fragment length polymorphism (RFLP). 3. The allele frequencies were similar to those described for other Spanish populations, namely 0.9% (95% confidence interval (CI) 0.5-1.3), 16.4% (95% CI 14.9-18.0), 2.7% (95% CI 2.0-3.4) and 0.7% (95% CI 0.3-1.0) for the *3, *4, *5 and *6 alleles, respectively. The results were satisfactory and left little doubt as to the genotypes, which were confirmed either by allelic discrimination assay (*4 and *6) or PCR-RFLP (*3) with 100% concordance. 4. The present study corroborates the low prevalence of the most frequent polymorphism (CYP2D6*4) that leads to null CYP2D6 activity in Spain and the allelic geographical gradient between Caucasian populations in the north and south. The present study reports a technique for the detection of four polymorphisms that account for 98% of the CYP2D6 defect alleles. This multiplex long PCR-SBE technique is a combination of several known methods to genotype CYP2D6 alleles (*3, *4, *5 and*6). Given the importance of CYP2D6 in drug metabolism and the need to genotype a large number of samples, we believe that this method will find broad application. PMID:17714084

  13. The role of reactive oxygen species (ROS) and cytochrome P-450 2E1 in the generation of carcinogenic etheno-DNA adducts

    PubMed Central

    Linhart, Kirsten; Bartsch, Helmut; Seitz, Helmut K.

    2014-01-01

    Exocyclic etheno-DNA adducts are mutagenic and carcinogenic and are formed by the reaction of lipidperoxidation (LPO) products such as 4-hydoxynonenal or malondialdehyde with DNA bases. LPO products are generated either via inflammation driven oxidative stress or via the induction of cytochrome P-450 2E1 (CYP2E1). In the liver CYP2E1 is induced by various compounds including free fatty acids, acetone and ethanol. Increased levels of CYP2E1 and thus, oxidative stress are observed in the liver of patients with non-alcoholic steatohepatitis (NASH) as well as in the chronic alcoholic. In addition, chronic ethanol ingestion also increases CYP2E1 in the mucosa of the oesophagus and colon. In all these tissues CYP2E1 correlates significantly with the levels of carcinogenic etheno-DNA adducts. In contrast, in patients with non-alcoholic steatohepatitis (NASH) hepatic etheno-DNA adducts do not correlate with CYP2E1 indicating that in NASH etheno-DNA adducts formation is predominately driven by inflammation rather than by CYP2E1 induction. Since etheno-DNA adducts are strong mutagens producing various types of base pair substitution mutations as well as other types of genetic damage, it is strongly believed that they are involved in ethanol mediated carcinogenesis primarily driven by the induction of CYP2E1. PMID:25462066

  14. Induction of CYP2E1 activity in liver transplant patients as measured by chlorzoxazone 6-hydroxylation

    PubMed Central

    Burckart, Gilbert J.; Frye, Reginald F.; Kelly, Patrick; Branch, Robert A.; Jain, Ashok; Fung, John J.; Starzl, Thomas E.; Venkataramanan, Raman

    2010-01-01

    Objective To examine the phenotypic expression of CYP2E1 in liver transplant patients, as measured by the in vivo probe chlorzoxazone, and to evaluate CYP2E1 activity over time after transplantation. Methods Thirty-three stable liver transplant patients were given 250 mg chlorzoxazone within 1 year after transplantation as part of a multiprobe CYP cocktail; urine and blood were collected for 8 hours. Chlorzoxazone and 6-hydroxychlorzoxazone concentrations were determined by HPLC. Twenty-eight healthy control subjects, eight patients with moderate to severe liver disease, and four patients who had not received liver transplants were also studied for comparison. The chlorzoxazone metabolic ratio, calculated as the plasma concentration of 6-hydroxychlorzoxazone/chlorzoxazone at 4 hours after chlorzoxazone administration, was used as the phenotypic index. In a subgroup of patients and control subjects, additional blood samples were obtained to allow for the calculation of chlorzoxazone pharmacokinetic parameters by noncompartmental methods. Results The chlorzoxazone metabolic ratio for the liver transplant patients in the first month after transplantation (mean ± SD, 6.4 ± 5.1) was significantly higher than that after 1 month after surgery (2.1 ± 2.0), when the chlorzoxazone metabolic ratio was not different from control subjects (0.8 ± 0.5). The chlorzoxazone metabolic ratios in the patients who had not received liver transplants (1.1 ± 0.7) were equivalent to those of healthy control subjects. The maximum observed 6-hydroxychlorzoxazone plasma concentration was 3046 ± 1848 ng/ml in seven liver transplant patients in the first month after surgery compared with 1618 ± 320 ng/ml in 16 healthy control subjects (p < 0.05). The maximum observed concentration of chlorzoxazone, the chlorzoxazone apparent oral clearance, and the formation clearance of 6-hydroxychlorzoxazone were also significantly different between the groups. Conclusions We conclude that significant

  15. Effect of Launaea procumbens extract on oxidative marker, p53, and CYP 2E1: a randomized control study

    PubMed Central

    Khan, Rahmat Ali; Khan, Muhammad Rashid; Sahreen, Sumaira; Alkreathy, Huda Mohammad

    2016-01-01

    Background Ethyl acetate extracts of Launaea procumbens is used for the treatment of liver dysfunction as an herbal medicine in Pakistan. In this study, the protective effects of ethyl acetate extracts were evaluated against CCl4-induced liver injuries in rat. Methods To examine the protective effects against oxidative stress of carbon tetrachloride in rats, 30 male rats were equally divided into 5 groups (6 rats). Among five groups, one was treated with CCl4 (3 ml/kg i.p. in olive oil b.w.) twice a week for 4 weeks. Others were orally fed with extracts (100, 200 mg/kg b.w.), with CCl4 twice a week for 4 weeks. Results Administration of CCl4 altered the serum marker enzymes, lipid profile, CYP 2E1, p53 expression, antioxidant enzymes, nuclear organizer regions (AgNORs), and DNA. Supplement of L. procumbens ameliorated the effects of CCl4, improved CYP 2E1, p53, and increased the activities of antioxidant enzymes while activity of liver marker enzymes (ALP, ALT, AST, g-GT) and contents of lipid per oxidation contents (TBARS), AgNORs, and DNA fragmentation were decreased. Similarly body weight was increased while liver and relative liver weight was decreased with co-administration of various extracts, suggesting that L. procumbens effectively protect liver against the CCl4-induced oxidative damage in rats. Conclusion The hepatoprotective and free radical scavenging effects might be due to the presence of bioactive constituents in the extract. PMID:26945232

  16. Structural comparison of cytochromes P450 2A6, 2A13, and 2E1 with pilocarpine

    SciTech Connect

    DeVore, Natasha M.; Meneely, Kathleen M.; Bart, Aaron G.; Stephens, Eva S.; Battaile, Kevin P.; Scott, Emily E.

    2013-11-20

    Human xenobiotic-metabolizing cytochrome P450 (CYP) enzymes can each bind and monooxygenate a diverse set of substrates, including drugs, often producing a variety of metabolites. Additionally, a single ligand can interact with multiple CYP enzymes, but often the protein structural similarities and differences that mediate such overlapping selectivity are not well understood. Even though the CYP superfamily has a highly canonical global protein fold, there are large variations in the active site size, topology, and conformational flexibility. We have determined how a related set of three human CYP enzymes bind and interact with a common inhibitor, the muscarinic receptor agonist drug pilocarpine. Pilocarpine binds and inhibits the hepatic CYP2A6 and respiratory CYP2A13 enzymes much more efficiently than the hepatic CYP2E1 enzyme. To elucidate key residues involved in pilocarpine binding, crystal structures of CYP2A6 (2.4 {angstrom}), CYP2A13 (3.0 {angstrom}), CYP2E1 (2.35 {angstrom}), and the CYP2A6 mutant enzyme, CYP2A6 I208S/I300F/G301A/S369G (2.1 {angstrom}) have been determined with pilocarpine in the active site. In all four structures, pilocarpine coordinates to the heme iron, but comparisons reveal how individual residues lining the active sites of these three distinct human enzymes interact differently with the inhibitor pilocarpine.

  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

    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.

  18. Binding of 7-methoxy-4-(aminomethyl)-coumarin to wild-type and W128F mutant cytochrome P450 2D6 studied by time-resolved fluorescence spectroscopy

    PubMed Central

    Stortelder, Aike; Keizers, Peter H. J.; Oostenbrink, Chris; De Graaf, Chris; De Kruijf, Petra; Vermeulen, Nico P. E.; Gooijer, Cees; Commandeur, Jan N. M.; Van Der Zwan, Gert

    2005-01-01

    Enzyme structure and dynamics may play a main role in substrate binding and the subsequent steps in the CYP (cytochrome P450) catalytic cycle. In the present study, changes in the structure of human CYP2D6 upon binding of the substrate are studied using steady-state and time-resolved fluorescence methods, focusing not only on the emission of the tryptophan residues, but also on emission of the substrate. As a substrate, MAMC [7-methoxy-4-(aminomethyl)-coumarin] was selected, a compound exhibiting native fluorescence. As well as the wild-type, the W128F (Trp128→Phe) mutant of CYP2D6 was studied. After binding, a variety of energy transfer possibilities exist, and molecular dynamics simulations were performed to calculate distances and relative orientations of donors and acceptors. Energy transfer from Trp128 to haem appeared to be important; its emission was related to the shortest of the three average tryptophan fluorescence lifetimes observed for CYP2D6. MAMC to haem energy transfer was very efficient as well: when bound in the active site, the emission of MAMC was fully quenched. Steady-state anisotropy revealed that besides the MAMC in the active site, another 2.4% of MAMC was bound outside of the active site to wild-type CYP2D6. The tryptophan residues in CYP2D6 appeared to be less accessible for the external quenchers iodide and acrylamide in presence of MAMC, indicating a tightening of the enzyme structure upon substrate binding. However, the changes in the overall enzyme structure were not very large, since the emission characteristics of the enzyme were not very different in the presence of MAMC. PMID:16190863

  19. Transgenic plants of Petunia hybrida harboring the CYP2E1 gene efficiently remove benzene and toluene pollutants and improve resistance to formaldehyde

    PubMed Central

    Zhang, Daoxiang; Xiang, Taihe; Li, Peihan; Bao, Lumin

    2011-01-01

    The CYP2E1 protein belongs to the P450 enzymes family and plays an important role in the metabolism of small molecular and organic pollutants. In this study we generated CYP2E1 transgenic plants of Petunia using Agrobacterium rhizogenes K599. PCR analysis confirmed that the regenerated plants contained the CYP2E1 transgene and the rolB gene of the Ri plasmid. Southern blotting revealed the presence of multiple copies of CYP2E1 in the genome of transgenic plants. Fluorescent quantitative PCR revealed exogenous CYP2E1 gene expression in CYP2E1 transgenic plants at various levels, whereas no like expression was detected in either GUS transgenic plants or wild-types. The absorption of benzene and toluene by transgenic plants was analyzed through quantitative gas chromatography. Transgenic plants with high CYP2E1 expression showed a significant increase in absorption capacity of environmental benzene and toluene, compared to control GUS transgenic and wild type plants. Furthermore, these plants also presented obvious improved resistance to formaldehyde. This study, besides being the first to reveal that the CYP2E1 gene enhances plant resistance to formaldehyde, also furnishes a new method for reducing pollutants, such as benzene, toluene and formaldehyde, by using transgenic flowering horticultural plants. PMID:22215968

  20. FASTING FOR LESS THAN 24 H INDUCES CYTOCHROME P450 2E1 AND 2B1/2ACTIVITIES IN RATS

    EPA Science Inventory

    Cytochrome p450 (CYP) 2E1 activity is induced after 24hr of fasting but no information is available for shorter fasting periods. e investigated the induction of CYP 2E1 in rats during the first 24 hours of food deprivation by examining marker activities for CYP isozymes 2b 1/2 an...

  1. 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

  2. Estrogen-related receptor γ controls hepatic CB1 receptor-mediated CYP2E1 expression and oxidative liver injury by alcohol

    PubMed Central

    Jang, Hyun-Hee; Park, Jinyoung; Kim, Jung Ran; Koh, Minseob; Jeong, Won-Il; Koo, Seung-Hoi; Park, Tae-Sik; Yun, Chul-Ho; Park, Seung Bum; Chiang, John Y L; Lee, Chul-Ho; Choi, Hueng-Sik

    2013-01-01

    Background The hepatic endocannabinoid system and cytochrome P450 2E1 (CYP2E1), a key enzyme causing alcohol-induced reactive oxygen species (ROS) generation, are major contributors to the pathogenesis of alcoholic liver disease. The nuclear hormone receptor oestrogen-related receptor γ (ERRγ) is a constitutively active transcriptional activator regulating gene expression. Objective To investigate the role of ERRγ in the alcohol-mediated regulation of CYP2E1 and to examine the possibility to control alcohol-mediated oxidative stress and liver injury through an ERRγ inverse agonist. Design For chronic alcoholic hepatosteatosis study, C57BL/6J wild-type and CB1−/− mice were administered alcohol for 4 weeks. GSK5182 and chlormethiazole (CMZ) were given by oral gavage for the last 2 weeks of alcohol feeding. Gene expression profiles and biochemical assays were performed using the liver or blood of mice. Results Hepatic ERRγ gene expression induced by alcohol-mediated activation of CB1 receptor results in induction of CYP2E1, while liver-specific ablation of ERRγ gene expression blocks alcohol-induced expression of CYP2E1 in mouse liver. An ERRγ inverse agonist significantly ameliorates chronic alcohol-induced liver injury in mice through inhibition of CYP2E1-mediated generation of ROS, while inhibition of CYP2E1 by CMZ abrogates the beneficial effects of the inverse agonist. Finally, chronic alcohol-mediated ERRγ and CYP2E1 gene expression, ROS generation and liver injury in normal mice were nearly abolished in CB1−/− mice. Conclusions ERRγ, as a previously unrecognised transcriptional regulator of hepatic CB1 receptor, controls alcohol-induced oxidative stress and liver injury through CYP2E1 induction, and its inverse agonist could ameliorate oxidative liver injury due to chronic alcohol exposure. PMID:23023167

  3. 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. PMID:21907728

  4. Utilizing structures of CYP2D6 and BACE1 complexes to reduce risk of drug-drug interactions with a novel series of centrally efficacious BACE1 inhibitors.

    PubMed

    Brodney, Michael A; Beck, Elizabeth M; Butler, Christopher R; Barreiro, Gabriela; Johnson, Eric F; Riddell, David; Parris, Kevin; Nolan, Charles E; Fan, Ying; Atchison, Kevin; Gonzales, Cathleen; Robshaw, Ashley E; Doran, Shawn D; Bundesmann, Mark W; Buzon, Leanne; Dutra, Jason; Henegar, Kevin; LaChapelle, Erik; Hou, Xinjun; Rogers, Bruce N; Pandit, Jayvardhan; Lira, Ricardo; Martinez-Alsina, Luis; Mikochik, Peter; Murray, John C; Ogilvie, Kevin; Price, Loren; Sakya, Subas M; Yu, Aijia; Zhang, Yong; O'Neill, Brian T

    2015-04-01

    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

  5. 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

  6. Structures of Human Cyctochrome P450 2E1: Insights Into the Binding of Inhibitors And Both Small Molecular Weight And Fatty Acid Substrates

    SciTech Connect

    Porubsky, P.R.; Meneely, K.M.; Scott, E.E.

    2009-05-21

    Human microsomal cytochrome P-450 2E1 (CYP2E1) monooxygenates >70 low molecular weight xenobiotic compounds, as well as much larger endogenous fatty acid signaling molecules such as arachidonic acid. In the process, CYP2E1 can generate toxic or carcinogenic compounds, as occurs with acetaminophen overdose, nitrosamines in cigarette smoke, and reactive oxygen species from uncoupled catalysis. Thus, the diverse roles that CYP2E1 has in normal physiology, toxicity, and drug metabolism are related to its ability to metabolize diverse classes of ligands, but the structural basis for this was previously unknown. Structures of human CYP2E1 have been solved to 2.2 {angstrom} for an indazole complex and 2.6 {angstrom} for a 4-methylpyrazole complex. Both inhibitors bind to the heme iron and hydrogen bond to Thr{sup 303} within the active site. Complementing its small molecular weight substrates, the hydrophobic CYP2E1 active site is the smallest yet observed for a human cytochrome P-450. The CYP2E1 active site also has two adjacent voids: one enclosed above the I helix and the other forming a channel to the protein surface. Minor repositioning of the Phe{sup 478} aromatic ring that separates the active site and access channel would allow the carboxylate of fatty acid substrates to interact with conserved {sup 216}QXXNN{sup 220} residues in the access channel while positioning the hydrocarbon terminus in the active site, consistent with experimentally observed {omega}-1 hydroxylation of saturated fatty acids. Thus, these structures provide insights into the ability of CYP2E1 to effectively bind and metabolize both small molecule substrates and fatty acids.

  7. Diallyl Sulfide: Potential Use in Novel Therapeutic Interventions in Alcohol, Drugs, and Disease Mediated Cellular Toxicity by Targeting Cytochrome P450 2E1

    PubMed Central

    Rao, PSS; Midde, Narasimha M; Miller, Duane D.; Chauhan, Subhash; Kumar, Anil; Kumar, Santosh

    2015-01-01

    Diallyl sulfide (DAS) and other organosulfur compounds are chief constituents of garlic. These compounds have many health benefits, as they are very efficient in detoxifying natural agents. Therefore, these compounds may be useful for prevention/treatment of cancers. However, DAS has shown appreciable allergic reactions and toxicity, as they can also affect normal cells. Thus their use as in the prevention and treatment of cancer is limited. DAS is a selective inhibitor of cytochrome P450 2E1 (CYP2E1), which is known to metabolize many xenobiotics including alcohol and analgesic drugs in the liver. CYP2E1-mediated alcohol/drug metabolism produce reactive oxygen species and reactive metabolites, which damage DNA, protein, and lipid membranes, subsequently causing liver damage. Several groups have shown that DAS is not only capable of inhibiting alcohol- and drug-mediated cellular toxicities, but also HIV protein- and diabetes-mediated toxicities by selectively inhibiting CYP2E1 in various cell types. However, due to known DAS toxicities, its use as a treatment modality for alcohol/drug- and HIV/diabetes-mediated toxicity have only limited clinical relevance. Therefore, effort is being made to generate DAS analogs, which are potent and selective inhibitor of CYP2E1 and poor substrate of CYP2E1. This review summarizes current advances in the field of DAS, its anticancer properties, role as a CYP2E1 inhibitor, preventing agent of cellular toxicities from alcohol, analgesic drugs, xenobiotics, as well as, from diseases like HIV and diabetes. Finally, this review also provides insights toward developing novel DAS analogues for chemical intervention of many disease conditions by targeting CYP2E1 enzyme. PMID:26264202

  8. Single-dose ethanol administration downregulates expression of cytochrome p450 2E1 mRNA in aldehyde dehydrogenase 2 knockout mice.

    PubMed

    Matsumoto, Akiko; Kawamoto, Toshihiro; Horita, Mikako; Takahashi, Tatsuya; Isse, Toyohi; Oyama, Tsunehiro; Ichiba, Masayoshi

    2007-12-01

    The polymorphism of aldehyde dehydrogenase 2 (ALDH2), denoted ALDH2*2, is very common in East Asian origin. Acetaldehyde, an intermediate metabolite of ethanol, is metabolized very slowly in people with ALDH2*2 because the mutant ALDH2 protein lacks the activity of acetaldehyde metabolism. On the other hand, it is well established that one of the cytochrome P450 enzymes, CYP2E1, is an activator of carcinogens (e.g., nitorosamines) and a generator of oxidative stress, and it is shown that CYP2E1 was induced by ethanol via gene transcriptional regulation. In the present study, to examine the consequences of ALDH2 polymorphism on transcriptional regulation of CYP2E1 in liver tissue, Aldh2+/+ and Aldh2-/- mice were orally administered 5 g/kg body weight of ethanol and the levels of CYP2E1 mRNA in liver tissue then analyzed. The level of CYP2E1 mRNA 12h after the ethanol administration tended to be higher than the 0-h group in Aldh2+/+ mice, however, it was significantly lower than the 0-h group in Aldh2-/- mice. These findings suggest that single-dose ethanol administration downregulates the expression of cytochrome p450 2E1 mRNA in the presence of inactive ALDH2. PMID:17980998

  9. Gene order for rubella virus structural proteins is NH/sub 2/-C-E2-E1-COOH

    SciTech Connect

    Oker-Blom, C.

    1984-08-01

    The order of translation in vivo of the genes coding for rubella virus structural proteins was studied in infected B-Vero cells. The proteins were sequentially pulse-chase labeled with (/sup 35/S)methionine after synchronization of translation initiation with hypertonic salt treatment. A sequential labeling procedure (window-labeling) to specifically label defined segments of the structural proteins was also used. The labeled proteins were identified by sodium dodecyl sulfate-gel electrophoresis after immunoprecipitation with specific antisera directed against the two virion glycoproteins (E1 and E2a/E2b) and the nucleocapsid (C) protein. The order of translation was found to be NH/sub 2/-C-E2-E1-COOH. We have previously shown that the structural proteins are synthesized in vitro from a cytoplasmic 24S subgenomic mRNA as a 110,000-dalton (p110) precursor. Here, it is shown that p110 is precipitated with anti-C, anti-E2, and anti-E1 sera, indicating that p110 is the precursor of all three structural proteins. Two major in vitro translation products (M/sub r/s, 66,000 and 62,000) that could represent preterminated polypeptide chains or proteolytic cleavage products were precipitated with anti-C and anti-Es sera, but not with anti-E1 serum, indicating, in conformity with the in vivo results, that the genes for the C and E2 proteins are adjacent to each other. Using these specific antisera, we have also confirmed the identity of the unglycosylated forms of E1 (M/sub r/, 53,000) and E2 (M/sub r/ 30,000) immunoprecipitated from tunicamycin-treated infected cells. 18 references, 6 figures.

  10. Differential role of CYP2E1-mediated metabolism in the lethal and vestibulotoxic effects of cis-crotononitrile in the mouse

    SciTech Connect

    Boadas-Vaello, Pere; Diez-Padrisa, Nuria; Llorens, Jordi

    2007-12-15

    Several alkylnitriles are toxic to sensory systems, including the vestibular system, through yet undefined mechanisms. This study addressed the hypothesis that the vestibular toxicity of cis-crotononitrile depends on CYP2E1-mediated bioactivation. Wild-type (129S1) and CYP2E1-null female mice were exposed to cis-crotononitrile at 0, 2, 2.25 or 2.5 mmol/kg (p.o.) in either a baseline condition or following exposure to 1% acetone in drinking water to induce CYP2E1 expression. The exposed animals were assessed for vestibular toxicity using a behavioral test battery and through surface observation of the vestibular sensory epithelia by scanning electron microscopy. In parallel groups, concentrations of cis-crotononitrile and cyanide were assessed in whole blood. Contrary to our hypothesis, CYP2E1-null mice were slightly more susceptible to the vestibular toxicity of cis-crotononitrile than were control 129S1 mice. Similarly, rather than enhance vestibular toxicity, acetone pretreatment actually reduced it slightly in 129S1 controls, although not in CYP2E1-null mice. In addition, significant differences in mortality were recorded, with the greatest mortality occurring in 129S1 mice after acetone pretreatment. The highest mortality recorded in the 129S1 + acetone mice was associated with the lowest blood concentrations of cis-crotononitrile and the highest concentrations of cyanide at 6 h after nitrile exposure, the time when deaths were initially recorded. We conclude that cis-crotononitrile is a CYP2E1 substrate as hypothesized, but that CYP2E1-mediated metabolism of this nitrile is not necessary for vestibular toxicity; rather, this metabolism constitutes a major pathway for cyanide release and subsequent lethality.

  11. Validation of 4-nitrophenol as an in vitro substrate probe for human liver CYP2E1 using cDNA expression and microsomal kinetic techniques.

    PubMed

    Tassaneeyakul, W; Veronese, M E; Birkett, D J; Gonzalez, F J; Miners, J O

    1993-12-01

    The involvement of human cytochrome P450 (CYP) 2E1 in the hydroxylation of 4-nitrophenol (4NP) to 4-nitrocatechol (4NC) has been investigated using cDNA expression and liver microsomal kinetic and inhibitor techniques. 4NP hydroxylation by human liver microsomes and cDNA-expressed human CYP2E1 exhibited Michaelis-Menten kinetics; the respective apparent Km values were 30 +/- 7 and 21 microM. Mutual competitive inhibition was observed for 4NP and chlorzoxazone (CZ) (an alternative human CYP2E1 substrate) in liver microsomes, with close similarities between the calculated apparent Km and Ki values for each individual compound. 4NP and CZ hydroxylase activities in microsomes from 18 liver donors varied to a similar extent (3.3- and 3.0-fold, respectively) and 4NP hydroxylase activity correlated significantly (rs > or = 0.75, P < 0.005) with both CZ hydroxylation and immunoreactive CYP2E1 content. The prototypic CYP2E1 inhibitor, diethyldithiocarbamate, was a potent inhibitor of 4NC formation and decreased 4NP hydroxylation by cDNA-expressed CYP2E1 and human liver microsomes in parallel. Probes for other human CYP isoforms namely (alpha-naphthoflavone, coumarin, sulphaphenazole, quinidine, troleandomycin and mephenytoin) caused < 15% inhibition of liver microsomal 4NP hydroxylation. These data confirm that, as in animal species, 4NP hydroxylation is catalysed largely by CYP2E1 in human liver and 4NP may therefore be used as an in vitro substrate probe for the human enzyme. PMID:8267647

  12. Association of CYP2D6*10, OATP1B1 A388G, and OATP1B1 T521C Polymorphisms and Overall Survival of Breast Cancer Patients after Tamoxifen Therapy

    PubMed Central

    Zhang, Xuefeng; Pu, Zhichen; Ge, Jun; Shen, Jie; Yuan, Xiaolong; Xie, Haitang

    2015-01-01

    Background The global incidence of breast cancer is increasing, mainly due to the sharp rise in breast cancer incidence in Asia. The aim of this study was to evaluate the association of CYP2D6*10 (c.100C>T and c.1039C>T), OATP1B1 A388G, and OATP1B1 T521C polymorphisms with overall survival (OS) for hormone receptor (estrogen receptor or progesterone receptor)-positive tumors (ER+/PR+) breast cancer patients after adjuvant tamoxifen (TAM) therapy. Material/Method We included 296 invasive breast cancer patients with hormone receptor-positive tumors during the period 2002–2009. We collected patient data, including clinical features, TAM therapy, and survival status. Archived paraffin blocks from surgery were the source of tissue for genotyping. CYP2D6*10, OATP1B1 A388G, and T521C polymorphisms were detected by direct sequencing of genomic DNA. OS was assessed with Kaplan-Meier analysis, while the Cox proportional hazards model was used to implement multivariate tests for the prognostic significance. Results There was a significant difference in OS between OATP1B1 T521C wild-type and the mutant genotype C carrier (P=0.034). However, there was no difference in overall survival between wild-type and carrier groups for CYP2D6*10 (P=0.096) and OATP1B1 A388G (P=0.388), respectively. Conclusions These results suggest that the OATP1B1 T521C mutation may be an independent prognostic marker for breast cancer patients using TAM therapy. PMID:25701109

  13. 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

  14. 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

    2012-01-01

    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

  15. Effect of CYP2E1 gene deletion in mice on expression of microsomal epoxide hydrolase in response to VCD exposure.

    PubMed

    Keating, Aileen F; Rajapaksa, Kathila S; Sipes, I Glenn; Hoyer, Patricia B

    2008-10-01

    Females are born with a finite number of primordial follicles. 4-Vinylcyclohexene diepoxide (VCD) is a metabolite formed by epoxidation of 4-vinylcyclohexene (VCH) via its two monoepoxides 1,2- and 7,8-4-vinylcyclohexene monoepoxide (VCM). VCD specifically destroys small preantral (primordial and small primary) follicles in the rodent ovary. The phase I enzyme, cytochrome P450 isoform 2E1 (CYP2E1) is involved in ovarian metabolism of VCM to VCD. Further, microsomal epoxide hydrolase (mEH) can detoxify VCD to an inactive tetrol (4-(1,2-dihydroxy)ethyl-1,2-dihydroxycyclohexane). This study evaluated the effects of VCD-induced ovotoxicity on mEH in CYP2E1+/+ and -/- mice (129S(1)/SvImJ background strain) using a postnatal day 4 mouse whole ovary culture system. The hypothesis of our study is that there is a relationship between CYP2E1 and mEH gene expression in the mouse ovary. Relative to control, VCD exposure caused follicle loss (p < 0.05) in ovaries from both genotypes; however, after 15 days, this loss was greater (p < 0.05) in CYP2E1+/+ ovaries. In a time course (2-15 days), relative to control, VCD (5 microM) caused an increase (p < 0.05) in mEH mRNA by 0.5-fold (day 10) and 1.84-fold (day 15) in CYP2E1-/- but not +/+ ovaries. 7,12-Dimethylbenz[a]anthracene (DMBA) also destroys ovarian follicles but, unlike VCD, is bioactivated by mEH to an ovotoxic 3,4-diol-1,2-epoxide metabolite. Incubation of ovaries in increasing concentrations of DMBA (0.5-1 microM, 15 days) resulted in greater (p < 0.05) follicle loss in CYP2E1-/-, relative to +/+ ovaries. With greater mEH (CYP2E1-/-), increased follicle loss with DMBA (bioactivation) and decreased follicle loss with VCD (detoxification) support that ovarian expression of CYP2E1 and mEH may be linked. PMID:18622027

  16. Human Cytochrome P450 2E1 Mutations That Alter Mitochondrial Targeting Efficiency and Susceptibility to Ethanol-induced Toxicity in Cellular Models*

    PubMed Central

    Bansal, Seema; Anandatheerthavarada, Hindupur K.; Prabu, Govindaswamy K.; Milne, Ginger L.; Martin, Martha V.; Guengerich, F. Peter; Avadhani, Narayan G.

    2013-01-01

    Human polymorphisms in the 5′-upstream regulatory regions and also protein coding regions of cytochrome P450 2E1 (CYP2E1) are known to be associated with several diseases, including cancer and alcohol liver toxicity. In this study, we report novel mutations in the N-terminal protein targeting regions of CYP2E1 that markedly affect subcellular localization of the protein. Variant W23R/W30R protein (termed W23/30R) is preferentially targeted to mitochondria but very poorly to the endoplasmic reticulum, whereas the L32N protein is preferentially targeted to the endoplasmic reticulum and poorly to mitochondria. These results explain the physiological significance of bimodal CYP targeting to the endoplasmic reticulum and mitochondria previously described. COS-7 cells and HepG2 cells stably expressing W23/30R mutations showed markedly increased alcohol toxicity in terms of increased production of reactive oxygen species, respiratory dysfunction, and loss of cytochrome c oxidase subunits and activity. Stable cells expressing the L32N variant, on the other hand, were relatively less responsive to alcohol-induced toxicity and mitochondrial dysfunction. These results further support our previous data, based on mutational studies involving altered targeting, indicating that mitochondria-targeted CYP2E1 plays an important role in alcohol liver toxicity. The results also provide an interesting new link to genetic variations affecting subcellular distribution of CYP2E1 with alcohol-induced toxicity. PMID:23471973

  17. Inhibition of cytochrome P450 2E1 and activation of transcription factor Nrf2 are renoprotective in myoglobinuric acute kidney injury.

    PubMed

    Wang, Zhe; Shah, Sudhir V; Liu, Hua; Baliga, Radhakrishna

    2014-08-01

    Rhabdomyolysis accounts for ∼10% of acute kidney injuries. In glycerol-induced myoglobinuric acute kidney injury, we found an increase in the nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear protein, a key redox-sensitive transcription factor, and Nrf2-regulated genes and proteins including upregulation of heme oxygenase-1. In in vitro studies, pretreatment of LLC-PK1 cells with an activator of Nrf2 before myoglobin exposure significantly decreased oxidant generation and cytotoxicity, whereas Nrf2 inhibition and gene silencing exacerbated the injury. Chlormethiazole, a specific CYP2E1 transcription inhibitor, prevented an increase in catalytic iron in the kidneys, decreased oxidative stress, blocked nuclear translocation of the Nrf2 protein, decreased heme oxygenase-1 upregulation, and provided functional and histological protection against acute kidney injury. CYP2E1 inhibitors and gene silencing in renal tubular epithelial cells significantly decreased reactive oxygen species generation and provided marked protection against myoglobin-induced cytotoxicity. Thus, during CYP2E1-induced oxidative stress, the transcription factor Nrf2 has a pivotal role in the early adaptive response. Inhibition of CYP2E1 coupled with the prior induction of Nrf2 may be a valuable tool to reduce CYP2E1-mediated rhabdomyolysis-induced acute kidney injury. PMID:24717297

  18. Simultaneous determination of metoprolol and its metabolites, α-hydroxymetoprolol and O-desmethylmetoprolol, in human plasma by liquid chromatography with tandem mass spectrometry: Application to the pharmacokinetics of metoprolol associated with CYP2D6 genotypes.

    PubMed

    Bae, Soo Hyeon; Lee, Joeng Kee; Cho, Doo-Yeoun; Bae, Soo Kyung

    2014-06-01

    A rapid and simple LC with MS/MS method for the simultaneous determination of metoprolol and its two CYP2D6-derived metabolites, α-hydroxy- and O-desmethylmetoprolol, in human plasma was established. Metoprolol (MET), its two metabolites, and the internal standard chlorpropamide were extracted from plasma (50 μL) using ethyl acetate. Chromatographic separation was performed on a Luna CN column with an isocratic mobile phase consisting of distilled water and methanol containing 0.1% formic acid (60:40, v/v) at a flow rate of 0.3 mL/min. The total run time was 3.0 min per sample. Mass spectrometric detection was conducted by ESI in positive ion selected-reaction monitoring mode. The linear ranges of concentration for MET, α-hydroxymetoprolol, and O-desmethylmetoprolol were 2-1000, 2-500, and 2-500 ng/mL, respectively, with a lower limit of quantification of 2 ng/mL for all analytes. The coefficient of variation for the assay's precision was ≤ 13.2%, and the accuracy was 89.1-110%. All analytes were stable under various storage and handling conditions and no relevant cross-talk and matrix effect were observed. Finally, this method was successfully applied to assess the influence of CYP2D6 genotypes on the pharmacokinetics of MET after oral administration of 100 mg to healthy Korean volunteers. PMID:24648255

  19. Targeted delivery of CYP2E1 recombinant adenovirus to malignant melanoma by bone marrow-derived mesenchymal stem cells as vehicles.

    PubMed

    Wang, Jishi; Ma, Dan; Li, Yan; Yang, Yuan; Hu, Xiaoyan; Zhang, Wei; Fang, Qin

    2014-03-01

    The aim of this study was to explore the effects of bone marrow-derived mesenchymal stem cells (BMSCs) as intermediate carriers on targeting of P450 gene recombinant adenovirus to malignant melanoma in vitro and in vivo. BMSCs were transduced with pAd5-CMV-CYP2E1 recombinant adenovirus. BMSC migration was detected by Transwell plates in vitro and by superparamagnetic iron oxide particles in vivo. Growth-inhibitory effect and apoptosis were determined by MTT and immunity fluorescence staining. Anticancer effects were examined by a human melanoma nude mouse model in vivo. BMSCs moved toward A375 cells in Transwell plates. Numerous superparamagnetic MSCs labeled with iron oxide were identified in the peripheral areas of the tumor, but were detected in primary organs by Prussian blue staining. BMSC-CYP2E1 cells mediated a bystander killing effect on CYP2E1-negative A375 cells during coculture (IC50 values for A375 cells cocultured with BMSC-EGFP and BMSC-CYP2E1 were 4.08 and 2.68 mmol/l, respectively). Intravenously injecting CYP2E1 recombinant adenovirus-loaded BMSCs in mice with established human melanoma managed to target the tumor site, and BMSCs with forced expression of CYP2E1 inhibited the growth of malignant cells in vivo by activating 5-(3,3-dimethyl-1-triazeno)imidazole-4-carboxamide. BMSCs may serve as a platform of P450 gene-directed enzyme prodrug therapy for the delivery of chemotherapeutic prodrugs to tumors. PMID:24413391

  20. Protective Role of CYP2E1 Inhibitor Diallyl Disulfide (DADS) on Alcohol Induced Malondialdehyde-Deoxyguanosine (M1dG) Adduct Formation

    PubMed Central

    Sapkota, M.; Hottor, T. K.; DeVasure, J. M.; Wyatt, T. A.; McCaskill, M. L.

    2014-01-01

    Background Alcohol use disorders are often associated with lung disease. Alcohol exposure leads to the production of reactive oxygen species, lipid peroxidation, and formation of malondialdehyde (MDA) as well as induce the expression of cytochrome p450 2E1 (CYP2E1). Likewise, cigarette smoking can lead to lung lipid peroxidation and formation of MDA. MDA can bind to DNA forming MDA deoxyguanosine (M1dG) adducts, which have been implicated in alcohol-related cancers and cardiovascular disease. Because CYP2E1 regulates MDA production, and our previous studies have shown that alcohol and cigarette smoke can lead to MDA formation, we hypothesized that CYP2E1 would modulate M1dG adduct formation and single strand DNA damage in alcohol- and cigarette smoke-exposed lung cells and tissue. Methods Normal human bronchial epithelial cells (HBEC) were pre-treated with 10 μM DADS for 1h, and treated with 80 mM ethanol +/− 5% cigarette smoke extract (CSE) for 3 hrs for comet assay and 6 hrs for CYP2E1, MDA, and M1dG adduct assays. C57BL/6 mice were administered 20% ethanol ad libitum in drinking water for 8 wk and exposed to whole body cigarette smoke for 5 wk. Mice were also fed a CYP2E1 inhibitor, diallyl disulfide (DADS), at 1 μM/g of feed in their daily diet for 7 wk. Whole lung tissue homogenate was used for CYP2E1, MDA, and M1dG adduct assays. Results Ethanol exposure significantly increased HBEC olive tail moment. DADS pretreatment of HBEC attenuated this ethanol effect. Ethanol also induced MDA and M1dG adduct formation, which was also significantly reduced by DADS treatment. CSE +/− ethanol did not enhance these effects. In lung tissue homogenate of 8 wk alcohol-fed mice, MDA and M1dG adduct levels were significantly elevated in comparison to control mice and mice fed DADS while consuming alcohol. No increase in MDA and M1dG adduct formation was observed in 5 wk cigarette smoke-exposed mice. Conclusions These findings suggest that CYP2E1 plays a pivotal role in

  1. Dietary tomato powder inhibits alcohol-induced hepatic injury by suppressing cytochrome p450 2E1 induction in rodent models.

    PubMed

    Stice, Camilla P; Liu, Chun; Aizawa, Koichi; Greenberg, Andrew S; Ausman, Lynne M; Wang, Xiang-Dong

    2015-04-15

    Chronic and excessive alcohol consumption leads to the development of alcoholic liver disease (ALD) and greatly increases the risk of liver cancer. Induction of the cytochrome p450 2E1 (CYP2E1) enzyme by chronic and excessive alcohol intake is known to play a role in the pathogenesis of ALD. High intake of tomatoes, rich in the carotenoid lycopene, is associated with a decreased risk of chronic disease. We investigated the effects of whole tomato (tomato powder, TP), partial tomato (tomato extract, TE), and purified lycopene (LYC) against ALD development in rats. Of the three supplements, only TP reduced the severity of alcohol-induced steatosis, hepatic inflammatory foci, and CYP2E1 protein levels. TE had no effect on these outcomes and LYC greatly increased inflammatory foci in alcohol-fed rats. To further support the protective effect of TP against ALD, TP was supplemented in a carcinogen (diethylnitrosamine, DEN)-initiated alcohol-promoted mouse model. In addition to reduced steatosis and inflammatory foci, TP abolished the presence of preneoplastic foci of altered hepatocytes in DEN-injected mice fed alcohol. These reductions were associated with decreased hepatic CYP2E1 protein levels, restored levels of peroxisome proliferator-activated receptor-α and downstream gene expression, decreased inflammatory gene expression, and reduced endoplasmic reticulum stress markers. These data provide strong evidence for TP as an effective whole food prevention strategy against ALD. PMID:25592162

  2. Effects of Flavonoids in Lysimachia clethroides Duby on the Activities of Cytochrome P450 CYP2E1 and CYP3A4 in Rat Liver Microsomes.

    PubMed

    Zhang, Zhi-Juan; Xia, Zhao-Yang; Wang, Jin-Mei; Song, Xue-Ting; Wei, Jin-Feng; Kang, Wen-Yi

    2016-01-01

    Incubation systems were established to investigate the effects of quercetin, kaempferol, isoquercitrin and astragalin in Lysimachia clethroides Duby on the activities of CYP2E1 and CYP3A4 in rat liver microsomes in vitro. Probe substrates of 4-nitrophenol and testosterone as well as flavonoids at different concentrations were added to the incubation systems. After incubation, a validated high performance liquid chromatography (HPLC) method was applied to separate and determine the relevant metabolites. The results suggested that kaempferol exhibited a weak inhibition of CYP2E1 activity with an IC50 of 60.26 ± 2.54 μM, while quercetin and kaempferol caused a moderate inhibition of CYP3A4 activity with IC50 values of 18.77 ± 1.69 μM and 32.65 ± 1.32 μM, respectively. Isoquercitrin and astragalin had no effects on the activities of either CYP2E1 or CYP3A4. It could be speculated from these results that the inhibitory effects of quercetin and kaempferol on the activities of CYP2E1 and CYP3A4 could be the mechanisms underlying the hepatoprotective effects of L. clethroides. PMID:27314315

  3. Ephedra water decoction and cough tablets containing ephedra and liquorice induce CYP1A2 but not CYP2E1 hepatic enzymes in rats.

    PubMed

    Tang, Jingling; Ji, Hongyu; Shi, Jing; Wu, Linhua

    2016-01-01

    1. Ephedra water decoction (EWD) and cough tablets containing ephedra and liquorice (maxing cough tablets, MXCT) have been widely used in the treatment of asthma. In the clinic, EWD and MXCT may be prescribed with theophylline, one of the most popular antiasthmatic drugs. CYP1A2 and CYP2E1 are mainly involved in the oxidative metabolism of theophylline in human liver. Drug interactions involving the cytochrome P450 (CYP) isoforms generally are of two types: enzyme induction or enzyme inhibition. Enzyme inhibition reduces metabolism, whereas induction can increase it. 2. To evaluate the pretreatment effect of EWD and MXCT on CYP1A2 and CYP2E1, CYP1A2 and CYP2E1 activity, the protein expression and mRNA expression levels were determined. After pretreatment with EWD or MXCT, the enzyme activity, mRNA expression and protein expression of CYP1A2 were increased significantly (p < 0.05), but enzyme activity of CYP2E1 did not change compared with the control. 3. It was demonstrated that EWD or MXCT pretreatment obviously induced CYP1A2, therefore, in patients taking EWD or MXCT, possible CYP-induced drug interaction should be noted to decrease the risk of therapeutic failure or adverse effects resulting from the use of additional therapeutic agents. PMID:26153439

  4. Nitric oxide donors prevent while the nitric oxide synthase inhibitor L-NAME increases arachidonic acid plus CYP2E1-dependent toxicity

    SciTech Connect

    Wu Defeng; Cederbaum, Arthur . E-mail: arthur.cederbaum@mssm.edu

    2006-10-15

    Polyunsaturated fatty acids such as arachidonic acid (AA) play an important role in alcohol-induced liver injury. AA promotes toxicity in rat hepatocytes with high levels of cytochrome P4502E1 and in HepG2 E47 cells which express CYP2E1. Nitric oxide (NO) participates in the regulation of various cell activities as well as in cytotoxic events. NO may act as a protectant against cytotoxic stress or may enhance cytotoxicity when produced at elevated concentrations. The goal of the current study was to evaluate the effect of endogenously or exogenously produced NO on AA toxicity in liver cells with high expression of CYP2E1 and assess possible mechanisms for its actions. Pyrazole-induced rat hepatocytes or HepG2 cells expressing CYP2E1 were treated with AA in the presence or absence of an inhibitor of nitric oxide synthase L-N {sup G}-Nitroarginine Methylester (L-NAME) or the NO donors S-nitroso-N-acetylpenicillamine (SNAP), and (Z)-1-[-(2-aminoethyl)-N-(2-aminoethyl)]diazen-1-ium-1,2-diolate (DETA-NONO). AA decreased cell viability from 100% to 48 {+-} 6% after treatment for 48 h. In the presence of L-NAME, viability was further lowered to 23 {+-} 5%, while, SNAP or DETA-NONO increased viability to 66 {+-} 8 or 71 {+-} 6%. The L-NAME potentiated toxicity was primarily necrotic in nature. L-NAME did not affect CYP2E1 activity or CYP2E1 content. SNAP significantly lowered CYP2E1 activity but not protein. AA treatment increased lipid peroxidation and lowered GSH levels. L-NAME potentiated while SNAP prevented these changes. Thus, L-NAME increased, while NO donors decreased AA-induced oxidative stress. Antioxidants prevented the L-NAME potentiation of AA toxicity. Damage to mitochondria by AA was shown by a decline in the mitochondrial membrane potential (MMP). L-NAME potentiated this decline in MMP in association with its increase in AA-induced oxidative stress and toxicity. NO donors decreased this decline in MMP in association with their decrease in AA

  5. Effect of polyphenolic compounds from Solanum torvum on plasma lipid peroxidation, superoxide anion and cytochrome P450 2E1 in human liver microsomes.

    PubMed

    Kusirisin, Winthana; Jaikang, Churdsak; Chaiyasut, Chaiyavat; Narongchai, Paitoon

    2009-11-01

    Previous studies presented evidence that plants contain antioxidants that have free radical-scavenging properties. Overproduction of free radicals leads to oxidative stress, a factor associated with a variety of diseases, such as diabetes. Cytochrome P450 2E1 enzymes (CYP2E1) are involved in drug metabolism in the liver and metabolism of DNA-reaction generating intra-mitochondrial ROS, which leads to micro- and macro-vascular pathology in diabetes. Plant-based chemicals can affect CYP2E1 enzymes and related defense mechanisms, possibly leading to protection against oxidative stress. We investigated the effect of Solanum torvum (ST) extracts on the inhibition of CYP2E1 activity in human liver microsomes. ST extract was analyzed for antioxidant activity by the ABTS method. Polyphenolic compounds were measured by the total phenol content using the Folin-Ciocalteau reagent. Flavonoid and tannin content were analyzed by standard methods. Oxidative stress was evaluated by measuring lipid peroxidation by TBARS and superoxide anion scavenging levels in plasma from diabetic patients. Results showed that 10 mg/ml of ST had CYP2E1 catalytic inhibiting activity (57.16 %). The IC50 value of CYP2E1 catalytic inhibiting activity level was 5.14 mg/ml by concentration in a dependent manner. One gram of concentrated ST extract had an antioxidant activity index of 3.68 mg of trolox and 360.53 mg of ascorbic acid equivalent. Effects on free radical-scavenging, as measured by TBARS and superoxide anion, showed IC50 values of 20.60 and 10.26 microg/ml, respectively. Polyphenolic compounds found included phenol, flavonoid and tannin, measuring 160.30, 104.36 and 65.91 mg/g, respectively. These results imply that ST is a natural source of polyphenolic antioxidants, which have cytochrome P450 2E1 enzyme inhibiting and free radical scavenging properties, as related to lipid peroxidation and superoxide anion activity. ST could potentially be used for reducing oxidative stress in diabetes

  6. Interactions between CYP2E1, GSTZ1 and GSTT1 polymorphisms and exposure to drinking water trihalomethanes and their association with semen quality.

    PubMed

    Yang, Pan; Zeng, Qiang; Cao, Wen-Cheng; Wang, Yi-Xin; Huang, Zhen; Li, Jin; Liu, Chong; Lu, Wen-Qing

    2016-05-01

    Trihalomethanes (THMs) have been reported to be associated with altered semen quality, and this association may be modified by inherited differences in cytochrome P450 (CYP2E1) and glutathione S-transferase (GSTZ1 and GSTT1), which metabolize THMs. We conducted a cross-sectional study to examine the interactions between CYP2E1, GSTZ1 and GSTT1 polymorphisms and exposure to THMs on semen quality among 401 men from the Reproductive Center of Tongji Hospital in Wuhan China. The baseline blood concentrations of four individual THMs, chloroform (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM) and bromoform (TBM), were measured as biomarkers of exposure to drinking water THMs. Genotypes were determined by real-time PCR, and semen-quality parameters were evaluated according to the World Health Organization guidelines. GSTT1 genotype significantly modified the association between exposure to Br-THMs (sum of BDCM, DBCM and TBM) and below-reference sperm motility (Pint=0.02). Men with above-median blood Br-THM levels had an increased odds ratio (OR) of below-reference sperm compared to men with below-median blood Br-THM levels (OR=2.15, 95% CI: 1.11, 4.19) in the GSTT1 null genotype only. In addition, we found that men with a TT of CYP2E1 rs 915,906 had higher blood TCM and TTHM (sum of TCM, BDCM, DBCM and TBM) concentrations than men with a CT/CC of CYP2E1 rs 915,906. Our results suggest that GSTT1 polymorphisms modify Br-THM exposure relation with semen quality, and CYP2E1 polymorphisms are associated with internal levels of exposure to THMs. PMID:26970898

  7. N-hydroxylation of 4-aminobiphenyl by CYP2E1 produces oxidative stress in a mouse model of chemically induced liver cancer.

    PubMed

    Wang, Shuang; Sugamori, Kim S; Tung, Aveline; McPherson, J Peter; Grant, Denis M

    2015-04-01

    4-Aminobiphenyl (ABP) is a trace component of cigarette smoke and hair dyes, a suspected human carcinogen and a potent rodent liver carcinogen. Postnatal exposure of mice to ABP results in a higher incidence of liver tumors in males than in females, paralleling the sex difference in human liver cancer incidence. A traditional model of ABP tumorigenesis involves initial CYP1A2-mediated N-hydroxylation, which eventually leads to production of mutagenic ABP-DNA adducts that initiate tumor growth. However, several studies have found no correlation between sex or CYP1A2 function and the DNA-damaging, mutagenic, or tumorigenic effects of ABP. Oxidative stress may be an important etiological factor for liver cancer, and it has also been linked to ABP exposure. The goals of this study were to identify novel enzyme(s) that contribute to ABP N-oxidation, and to investigate a potential role for oxidative stress in ABP liver tumorigenicity. Isozyme-selective inhibition experiments using liver microsomes from wild-type and genetically modified mice identified CYP2E1 as a major ABP N-hydroxylating enzyme. The N-hydroxylation of ABP by transiently expressed CYP2E1 produced oxidative stress in cultured mouse hepatoma cells. In vivo postnatal exposure of mice to a tumorigenic dose of ABP also produced oxidative stress in male wild-type mice, but not in male Cyp2e1(-/-) mice or in female mice. However, a stronger NRF2-associated antioxidant response was observed in females. Our results identify CYP2E1 as a novel ABP-N-oxidizing enzyme, and suggest that sex differences in CYP2E1-dependent oxidative stress and antioxidant responses to ABP may contribute to the observed sex difference in tumor incidence. PMID:25601990

  8. N-Hydroxylation of 4-Aminobiphenyl by CYP2E1 Produces Oxidative Stress in a Mouse Model of Chemically Induced Liver Cancer

    PubMed Central

    Wang, Shuang; Sugamori, Kim S.; Tung, Aveline; McPherson, J. Peter; Grant, Denis M.

    2015-01-01

    4-Aminobiphenyl (ABP) is a trace component of cigarette smoke and hair dyes, a suspected human carcinogen and a potent rodent liver carcinogen. Postnatal exposure of mice to ABP results in a higher incidence of liver tumors in males than in females, paralleling the sex difference in human liver cancer incidence. A traditional model of ABP tumorigenesis involves initial CYP1A2-mediated N-hydroxylation, which eventually leads to production of mutagenic ABP-DNA adducts that initiate tumor growth. However, several studies have found no correlation between sex or CYP1A2 function and the DNA-damaging, mutagenic, or tumorigenic effects of ABP. Oxidative stress may be an important etiological factor for liver cancer, and it has also been linked to ABP exposure. The goals of this study were to identify novel enzyme(s) that contribute to ABP N-oxidation, and to investigate a potential role for oxidative stress in ABP liver tumorigenicity. Isozyme-selective inhibition experiments using liver microsomes from wild-type and genetically modified mice identified CYP2E1 as a major ABP N-hydroxylating enzyme. The N-hydroxylation of ABP by transiently expressed CYP2E1 produced oxidative stress in cultured mouse hepatoma cells. In vivo postnatal exposure of mice to a tumorigenic dose of ABP also produced oxidative stress in male wild-type mice, but not in male Cyp2e1(−/−) mice or in female mice. However, a stronger NRF2-associated antioxidant response was observed in females. Our results identify CYP2E1 as a novel ABP-N-oxidizing enzyme, and suggest that sex differences in CYP2E1-dependent oxidative stress and antioxidant responses to ABP may contribute to the observed sex difference in tumor incidence. PMID:25601990

  9. Effect of sulfur dioxide inhalation on CYP2B1/2 and CYP2E1 in rat liver and lung

    SciTech Connect

    Guohua Qin; Ziqiang Meng

    2006-07-15

    Sulfur dioxide (SO{sub 2}) is a ubiquitous air pollutant, present in low concentrations in the urban air and in higher concentrations in the working environment. In this study, we investigated the effects of inhaled SO{sub 2} on the O-dealkylase of pentoxyresorufin (PROD) and p-nitrophenol hydroxylases (p-NP) activities and mRNA levels of CYP2B1/2 and CYP2E1 in the lung and liver of Wistar rats. Male Wistar rats were housed in exposure chambers and treated with 14.11 {+-}1.53, 28.36 {+-} 2.12, and 56.25 {+-} 4.28 mg /m{sup 3}SO{sub 2} for 6 h/day for 7 days, while control rats were exposed to filtered air in the same condition. The mRNAs of CYP2B1/2 and -2E1 were analyzed in livers and lungs by using reverse-transcription polymerase chain reaction (RT-PCR). Results showed that the PROD activities and mRNA of CYP2B1/2 were decreased in livers and lungs of rats exposed to SO{sub 2}. The p-NP activities and mRNA of CYP2E1 were decreased in lungs but not in livers of rats exposed to SO{sub 2}. Total liver microsomal cytochrome P-450 (CYP) contents were diminished in SO{sub 2} -exposed rats. These results lead to two conclusions: (1) SO{sub 2} exposure can suppress CYP2B1/2 and CYP2E1 in lungs and CYP2B1/2 in livers of rats, thus modifying the liver and lung toxication/detoxication potential, and (2) the total liver microsomal CYP contents were diminished, although the activity and mRNA expression of CYP2E1 in rat livers were not affected by SO{sub 2} exposure.

  10. Over-Expression of Either MECP2_e1 or MECP2_e2 in Neuronally Differentiated Cells Results in Different Patterns of Gene Expression

    PubMed Central

    Orlic-Milacic, Marija; Kaufman, Liana; Mikhailov, Anna; Cheung, Aaron Y. L.; Mahmood, Huda; Ellis, James; Gianakopoulos, Peter J.; Minassian, Berge A.; Vincent, John B.

    2014-01-01

    Mutations in MECP2 are responsible for the majority of Rett syndrome cases. MECP2 is a regulator of transcription, and has two isoforms, MECP2_e1 and MECP2_e2. There is accumulating evidence that MECP2_e1 is the etiologically relevant variant for Rett. In this study we aim to detect genes that are differentially transcribed in neuronal cells over-expressing either of these two MECP2 isoforms. The human neuroblastoma cell line SK-N-SH was stably infected by lentiviral vectors over-expressing MECP2_e1, MECP2_e2, or eGFP, and were then differentiated into neurons. The same lentiviral constructs were also used to infect mouse Mecp2 knockout (Mecp2tm1.1Bird) fibroblasts. RNA from these cells was used for microarray gene expression analysis. For the human neuronal cells, ∼800 genes showed >three-fold change in expression level with the MECP2_e1 construct, and ∼230 with MECP2_e2 (unpaired t-test, uncorrected p value <0.05). We used quantitative RT-PCR to verify microarray results for 41 of these genes. We found significant up-regulation of several genes resulting from over-expression of MECP2_e1 including SRPX2, NAV3, NPY1R, SYN3, and SEMA3D. DOCK8 was shown via microarray and qRT-PCR to be upregulated in both SK-N-SH cells and mouse fibroblasts. Both isoforms up-regulated GABRA2, KCNA1, FOXG1 and FOXP2. Down-regulation of expression in the presence of MECP2_e1 was seen with UNC5C and RPH3A. Understanding the biology of these differentially transcribed genes and their role in neurodevelopment may help us to understand the relative functions of the two MECP2 isoforms, and ultimately develop a better understanding of RTT etiology and determine the clinical relevance of isoform-specific mutations. PMID:24699272

  11. Cytochrome P450 2E1 RsaI/PstI polymorphism and risk of esophageal cancer: A meta-analysis of 17 case-control studies

    PubMed Central

    LENG, WEI-DONG; ZENG, XIAN-TAO; CHEN, YONG-JI; DUAN, XIAO-LI; NIU, YU-MING; LONG, RONG-PEI; LUO, ZHI-XIAO

    2012-01-01

    The aim of this study was to explore the cytochrome P450 2E1 (CYP2E1) RsaI/PstI polymorphism and risk of esophageal cancer (EC) in mainland Chinese populations. A systematic search of PubMed, EMBASE, Web of Science, CBM, CNKI and VIP databases for publications on the CYP2E1 RsaI/PstI polymorphism and risk of EC was performed. and the genotype data were analyzed in a meta-analysis. Odds ratios (ORs) with relevant 95% confidence intervals (CIs) were estimated to assess the association. Sensitivity analysis, test of heterogeneity and assessment of publication bias were performed. The search yielded 17 studies including 18 trails involving 1,663 cases and 2,603 controls. The meta-analyses showed a significant association between the CYP2E1 RsaI/PstI polymorphism and risk of EC in the mainland Chinese population (c2 vs. c1: OR=0.64; 95% CI, 0.50–0.81; P<0.001; c2/c2 vs. c1/c1: OR=0.73; 95% CI, 0.57–0.93; c2/c2 vs. c1/c1+c1/c2: OR=0.76; 95% CI, 0.60–0.96; P=0.02; c1/c2 vs. c1/c1: OR=0.54; 95% CI, 0.38–0.75; P<0.001; c1/c2+c2/c2 vs. c1/c1: OR=0.48; 95% CI, 0.34–0.70; P<0.001). An increased cancer risk in all genetic models was identified following stratification by ethnicity, source of controls and tumor type. In conclusion, in all genetic models, the association between the CYP2E1 RsaI/PstI polymorphism and risk of EC in the mainland Chinese population was significant. This meta-analysis suggests that the CYP2E1 RsaI/PstI polymorphism is a risk factor for EC, and the c2 allele is a factor that lowers the possibility of EC in the mainland Chinese population and this association did not change due to ethnic differences in genetic backgrounds and the environment. PMID:23226753

  12. Genotoxicity of 1-methylpyrene and 1-hydroxymethylpyrene in Chinese hamster V79-derived cells expressing both human CYP2E1 and SULT1A1.

    PubMed

    Jiang, Hao; Lai, Yanmei; Hu, Keqi; Chen, Danxun; Liu, Bixuan; Liu, Yungang

    2015-05-01

    1-Methylpyrene (1-MP) is a widespread pollutant that is carcinogenic in animals following metabolic activation. Previous studies have shown that benzylic hydroxylation of 1-MP, catalyzed by multiple CYP isoforms, gives rise to 1-hydroxymethylpyrene (1-HMP), which becomes bioreactive following further metabolism by various sulfotransferase (SULT) isoforms. However, the mutagenic and chromosome damaging effects of 1-MP and 1-HMP in mammalian cells have not been investigated. In this study a Chinese hamster V79-derived cell line expressing both human CYP2E1 and human SULT1A1 was used to investigate the ability of 1-MP and 1-HMP to induce cytotoxicity (using the CCK-8 assay), micronuclei and Hprt gene mutations. The role of each enzyme was investigated through co-exposure in the presence of an enzyme inhibitor. We found that at concentrations of 0.5-4 μM and 5-20 μM, under conditions where no reduction in cell viability/growth occurred, 1-HMP and 1-MP induced micronuclei in V79-hCYP2E1-hSULT1A1 cells in a concentration-dependent manner; however, both compounds were inactive in V79 cells. Similarly, they both caused an increase in Hprt mutant frequency in V79-hCYP2E1-hSULT1A1 cells in these concentration ranges, with 1-MP impairing cell viability/growth at 10 μM and above in the mutagenicity assay. The compounds were again both inactive in V79 cells. The effects of 1-HMP in V79-hCYP2E1-hSULT1A1 cells were blocked or reduced by addition of pentachlorophenol (PCP), a SULT1 inhibitor; the genotoxicity of 1-MP was significantly reduced by either 1-aminobenotrazole, a CYP2E1 inhibitor, or PCP. The results suggest that human CYP2E1 and SULT1A1 cooperate to activate 1-MP and cause genotoxicity in mammalian cells. PMID:25243916

  13. Modeling interchild differences in pharmacokinetics on the basis of subject-specific data on physiology and hepatic CYP2E1 levels: A case study with toluene

    SciTech Connect

    Nong, A.; McCarver, D.G.; Hines, R.N.; Krishnan, K. . E-mail: Kannan.Krishnan@umontreal.ca

    2006-07-01

    The objective of the present study was to evaluate the magnitude of interindividual variability in the internal dose of toluene in children of various age groups, on the basis of subject-specific hepatic CYP2E1 content and physiology. The methodology involved the use of a previously validated physiologically based pharmacokinetic (PBPK) model, in which the intrinsic clearance for hepatic metabolism (CL{sub int}) was expressed in terms of the CYP2E1 content. The adult toluene PBPK model, with enzyme content-normalized CL{sub int}, facilitated the calculation of child-specific CL{sub int} based on knowledge of hepatic CYP2E1 protein levels. The child-specific physiological parameters, except liver volume, were computed with knowledge of age and body weight, whereas physicochemical parameters for toluene were kept age-invariant based on available data. The actual individual-specific liver volume (autopsy data) was also included in the model. The resulting model was used to simulate the blood concentration profiles in children exposed by inhalation, to 1 ppm toluene for 24 h. For this exposure scenario, the area under the venous blood concentration vs. time curve (AUC) ranged from 0.30 to 1.01 {mu}g/ml x h in neonates with low CYP2E1 concentration (<3.69 pmol/mg protein). The simulations indicated that neonates with higher levels of CYP2E1 (4.33 to 55.93 pmol/mg protein) as well as older children would have lower AUC (0.16 to 0.43 {mu}g/ml x h). The latter values were closer to those simulated for adults. Similar results were also obtained for 7 h exposure to 17 ppm toluene, a scenario previously evaluated in human volunteers. The interindividual variability factor for each subgroup of children and adults, calculated as the ratio of the 95th and 50th percentile values of AUC, was within a factor of 2. The 95th percentile value of the low metabolizing neonate group, however, was greater than the mean adult AUC by a factor of 3.9. This study demonstrates the f