Journal articles: 'CYP2B6'

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Ma, Wenjuan, Wei Wang, Xuhua Huang, Guangzhe Yao, Qi Jia, Jiayuan Shen, Huizi Ouyang, Yanxu Chang, and Jun He. "HPLC-MS/MS Analysis of Aconiti Lateralis Radix Praeparata and Its Combination with Red Ginseng Effect on Rat CYP450 Activities Using the Cocktail Approach." Evidence-Based Complementary and Alternative Medicine 2020 (March 9, 2020): 1–12. http://dx.doi.org/10.1155/2020/8603934.

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Red ginseng is often combined with Aconiti Lateralis Radix Praeparata to reduce alkaloids-related toxicity of the latter. Such herb-pairing also results in better therapeutic effect in heart failure, as compared to the singular use of either herb. The purpose of this study was to investigate the effect of Aconiti Lateralis Radix Praeparata and its combination with red ginseng on the activities of CYP450 enzymes in rats. A sensitive and reliable HPLC-MS/MS method was established and validated for the simultaneous determination of eight probe drugs, phenacetin (CYP1A2), tolbutamide (CYP2C9), omeprazole (CYP2C19), dextromethorphan (CYP2D6), dapsone (CYP3A4), 7-hydroxycoumarin (CYP2A6), bupropion (CYP2B6), and amodiaquine (CYP2C8), in rat plasma using diazepam as internal standard (IS). The chromatographic separation was performed on a Waters XBridge™ C18 column (2.1 mm × 100 mm, 3.5 μm) using a gradient elution with the mobile phase consisting of acetonitrile and water (containing 0.1% formic acid) at a flow rate of 0.3 mL/min. The method was successfully applied in evaluating the effect of Aconiti Lateralis Radix Praeparata and red ginseng on the activities of CYP450 enzymes. The pharmacokinetic results of the eight probe drugs suggested that Aconiti Lateralis Radix Praeparata may inhibit the activity of CYP2A6, CYP2C19, CYP2B6, CYP1A2, CYP3A4, and CYP2C9 enzymes in rats. Comparison between the two groups, Aconiti Lateralis Radix Praeparata combined with red ginseng and Aconiti Lateralis Radix Praeparata, indicated that red ginseng may inhibit the activity of CYP2D6 and CYP2B6 enzymes while inducing the activity of CYP1A2, CYP3A4, and CYP2C9 enzymes.

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Lim, Sharoen Yu Ming, Mustafa Ahmed Alshagga, Mohammed Abdullah Alshawsh, Chin Eng Ong, and Yan Pan. "In vitro effects of 95% khat ethanol extract (KEE) on human recombinant cytochrome P450 (CYP)1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C19, CYP2E1, CYP2J2 and CYP3A5." Drug Metabolism and Personalized Therapy 37, no. 1 (August 17, 2021): 55–67. http://dx.doi.org/10.1515/dmpt-2021-1000196.

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Abstract Objectives Khat, a natural amphetamine-like psychostimulant plant, are widely consumed globally. Concurrent intake of khat and xenobiotics may lead to herb-drug interactions and adverse drug reactions (ADRs). This study is a continuation of our previous study, targeted to evaluate the in vitro inhibitory effects of khat ethanol extract (KEE) on human cytochrome (CYP) 1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C19, CYP2E1, CYP2J2, and CYP3A5, major human drug metabolizing enzymes. Methods In vitro fluorescence enzyme assays were employed to assess CYPs inhibition with the presence and absence of various KEE concentrations. Results KEE reversibly inhibited CYP2A6, CYP2B6, CYP2C8, CYP2C19, CYP2E1, CYP2J2 and CYP3A5 but not CYP1A2 with IC50 values of 25.5, 99, 4.5, 21, 27, 17, and 10 μg/mL respectively. No irreversible inhibition of KEE on all the eight CYPs were identified. The Ki values of CYP2A6, CYP2B6, CYP2C8, CYP2C19, CYP2E1, CYP2J2 and CYP3A5 were 20.9, 85, 4.8, 18.3, 59.3, 3, and 21.7 μg/mL, respectively. KEE inhibited CYP2B6 via competitive or mixed inhibition; CYP2E1 via un-competitive or mixed inhibition; while CYP2A6, CYP2C8, CYP2C19, CYP2J2 and CYP3A5 via non-competitive or mixed inhibition. Conclusions Caution should be taken by khat users who are on medications metabolized by CYP2A6, CYP2B6, CYP2C8, CYP2C19, CYP2E1, CYP2J2, and CYP3A5.

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Claw, Katrina G., Julie A. Beans, Seung-Been Lee, Jaedon P. Avey, Patricia A. Stapleton, Steven E. Scherer, Ahmed El-Boraie, et al. "Pharmacogenomics of Nicotine Metabolism: Novel CYP2A6 and CYP2B6 Genetic Variation Patterns in Alaska Native and American Indian Populations." Nicotine & Tobacco Research 22, no. 6 (June 25, 2019): 910–18. http://dx.doi.org/10.1093/ntr/ntz105.

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Abstract Introduction Alaska Native and American Indian (AN/AI) populations have higher tobacco use prevalence than other ethnic/racial groups. Pharmacogenetic testing to tailor tobacco cessation treatment may improve cessation rates. This study characterized polymorphic variations among AN/AI people in genes associated with metabolism of nicotine and drugs used for tobacco cessation. Methods Recruitment of AN/AI individuals represented six subgroups, five geographic subgroups throughout Alaska and a subgroup comprised of AIs from the lower 48 states living in Alaska. We sequenced the CYP2A6 and CYP2B6 genes to identify known and novel gain, reduced, and loss-of-function alleles, including structural variation (eg, gene deletions, duplications, and hybridizations). Results Variant allele frequencies differed substantially between AN/AI subgroups. The gene deletion CYP2A6*4 and reduced function CYP2A6*9 alleles were found at high frequency in Northern/Western subgroups and in Lower 48/Interior subgroups, respectively. The reduced function CYP2B6*6 allele was observed in all subgroups and a novel, predicted reduced function CYP2B6 variant was found at relatively high frequency in the Southeastern subgroup. Conclusions Diverse CYP2A6 and CYP2B6 variation among the subgroups highlight the need for comprehensive pharmacogenetic testing to guide tobacco cessation therapy for AN/AI populations. Implications Nicotine metabolism is largely determined by CYP2A6 genotype, and variation in CYP2A6 activity has altered the treatment success in other populations. These findings suggest pharmacogenetic-guided smoking cessation drug treatment could provide benefit to this unique population seeking tobacco cessation therapy.

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Hashemi-Soteh, Mohammad Bagher, Elaheh Hosseini, Shokoufeh Fazelnia, Faramarz Ghasemian-Sorbeni, Sara Madahian, and Mohammad Reza Shiran. "Frequencies of CYP2B6∗4,∗5, and ∗6 Alleles within an Iranian Population (Mazandaran)." Genetics Research 2021 (December 2, 2021): 1–6. http://dx.doi.org/10.1155/2021/8703812.

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Background. The human CYP2B subfamily consists of one functional gene (CYP2B6) and one pseudogene (CYP2B7P). Cytochrome P450 2B6 (CYP2B6) is a highly polymorphic enzyme that shows marked interindividual and interethnic variations. Currently, 38 alleles have been described, and some of the allelic variants have been associated with low enzyme activity. The aim of this study was to investigate the frequencies of CYP2B6∗4, CYP2B6∗5, and CYP2B6∗6 alleles in the Mazani ethnic group among Iranian Population. Methods. The study was conducted in 289 unrelated healthy volunteers. DNA was extracted from peripheral blood and analyzed by the PCR-RFLP protocol. The PCR product was digested with restriction enzymes and then separated using agarose gel electrophoresis. Results. The frequency of CYP2B6∗4, CYP2B6∗5, and CYP2B6∗6 in this study was 34.60%, 7.26%, and 34.54%, respectively. Conclusion. The frequency of the CYP2B6∗4 allele in the Mazani ethnic group was much higher (34.60%) than other population. The frequency of CYP2B6∗6 (34.54%) also was higher than its frequency in other previously reported population. But the frequency of CYP2B6∗5 in this study was lower than expected. These results will be useful in understanding the ethnic diversity in Iranian population and offer a preliminary basis for more rational use of drugs that are substrates for CYP2B6 in this population.

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Jeong, Seongwook, Phuong D. Nguyen, and Zeruesenay Desta. "Comprehensive In Vitro Analysis of Voriconazole Inhibition of Eight Cytochrome P450 (CYP) Enzymes: Major Effect on CYPs 2B6, 2C9, 2C19, and 3A." Antimicrobial Agents and Chemotherapy 53, no. 2 (November 24, 2008): 541–51. http://dx.doi.org/10.1128/aac.01123-08.

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ABSTRACT Voriconazole is an effective antifungal drug, but adverse drug-drug interactions associated with its use are of major clinical concern. To identify the mechanisms of these interactions, we tested the inhibitory potency of voriconazole with eight human cytochrome P450 (CYP) enzymes. Isoform-specific probes were incubated with human liver microsomes (HLMs) (or expressed CYPs) and cofactors in the absence and the presence of voriconazole. Preincubation experiments were performed to test mechanism-based inactivation. In pilot experiments, voriconazole showed inhibition of CYP2B6, CYP2C9, CYP2C19, and CYP3A (half-maximal [50%] inhibitory concentrations, <6 μM); its effect on CYP1A2, CYP2A6, CYP2C8, and CYP2D6 was marginal (<25% inhibition at 100 μM voriconazole). Further detailed experiments with HLMs showed that voriconazole is a potent competitive inhibitor of CYP2B6 (Ki < 0.5), CYP2C9 (Ki = 2.79 μM), and CYP2C19 (Ki = 5.1 μM). The inhibition of CYP3A by voriconazole was explained by noncompetitive (Ki = 2.97 μM) and competitive (Ki = 0.66 μM) modes of inhibition. Prediction of the in vivo interaction of voriconazole from these in vitro data suggests that voriconazole would substantially increase the exposure of drugs metabolized by CYP2B6, CYP2C9, CYP2C19, and CYP3A. Clinicians should be aware of these interactions and monitor patients for adverse effects or failure of therapy.

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Heintz, Melissa M., Jazmine A. Eccles, Emily M. Olack, Kristal M. Maner-Smith, Eric A. Ortlund, and William S. Baldwin. "Human CYP2B6 produces oxylipins from polyunsaturated fatty acids and reduces diet-induced obesity." PLOS ONE 17, no. 12 (December 15, 2022): e0277053. http://dx.doi.org/10.1371/journal.pone.0277053.

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Multiple factors in addition to over consumption lead to obesity and non-alcoholic fatty liver disease (NAFLD) in the United States and worldwide. CYP2B6 is the only human detoxification CYP whose loss is associated with obesity, and Cyp2b-null mice show greater diet-induced obesity with increased steatosis than wildtype mice. However, a putative mechanism has not been determined. LC-MS/MS revealed that CYP2B6 metabolizes PUFAs, with a preference for metabolism of ALA to 9-HOTrE and to a lesser extent 13-HOTrE with a preference for metabolism of PUFAs at the 9- and 13-positions. To further study the role of CYP2B6 in vivo, humanized-CYP2B6-transgenic (hCYP2B6-Tg) and Cyp2b-null mice were fed a 60% high-fat diet for 16 weeks. Compared to Cyp2b-null mice, hCYP2B6-Tg mice showed reduced weight gain and metabolic disease as measured by glucose tolerance tests, however hCYP2B6-Tg male mice showed increased liver triglycerides. Serum and liver oxylipin metabolite concentrations increased in male hCYP2B6-Tg mice, while only serum oxylipins increased in female hCYP2B6-Tg mice with the greatest increases in LA oxylipins metabolized at the 9 and 13-positions. Several of these oxylipins, specifically 9-HODE, 9-HOTrE, and 13-oxoODE, are PPAR agonists. RNA-seq data also demonstrated sexually dimorphic changes in gene expression related to nuclear receptor signaling, especially CAR > PPAR with qPCR suggesting PPARγ signaling is more likely than PPARα signaling in male mice. Overall, our data indicates that CYP2B6 is an anti-obesity enzyme, but probably to a lesser extent than murine Cyp2b’s. Therefore, the inhibition of CYP2B6 by xenobiotics or dietary fats can exacerbate obesity and metabolic disease potentially through disrupted PUFA metabolism and the production of key lipid metabolites.

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Saiz-Rodríguez, Miriam, Dolores Ochoa, Manuel Román, Pablo Zubiaur, Dora Koller, Gina Mejía, and Francisco Abad-Santos. "Involvement of CYP2D6 and CYP2B6 on tramadol pharmacokinetics." Pharmacogenomics 21, no. 10 (July 2020): 663–75. http://dx.doi.org/10.2217/pgs-2020-0026.

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This study included 24 healthy volunteers who received a single 37.5 mg oral dose of tramadol. We analyzed 18 polymorphisms within CYP2D6, CYP2B6, CYP3A, COMT, ABCB1, SLC22A1 and OPRM1 genes by quantitative PCR, to study whether these polymorphisms affect its pharmacokinetics, pharmacodynamics and safety. CYP2D6 intermediate metabolizers (n = 6) showed higher tramadol plasma concentrations and lower clearance compared with normal and ultrarapid metabolizers. CYP2B6 G516T T/T (n = 2) genotype was also associated to higher tramadol plasma levels. No other polymorphism affected tramadol pharmacokinetics. Three volunteers experienced a prolonged QTc not associated with the genetic variants studied or altered phamacokinetic parameters. The correlation of CYP2B6 genotype with higher tramadol concentrations is remarkable since its influence on its elimination is also relevant and has been less studied to date. However, given our small sample size, it is important to interpret our results with caution.

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Li, Lang, Silvana Borges, Robarge D. Jason, Changyu Shen, Zeruesenay Desta, and David Flockhart. "A Penalized Mixture Model Approach in Genotype/Phenotype Association Analysis for Quantitative Phenotypes." Cancer Informatics 9 (January 2010): CIN.S3493. http://dx.doi.org/10.4137/cin.s3493.

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A mixture normal model has been developed to partition genotypes in predicting quantitative phenotypes. Its estimation and inference are performed through an EM algorithm. This approach can conduct simultaneous genotype clustering and hypothesis testing. It is a valuable method for predicting the distribution of quantitative phenotypes among multi-locus genotypes across genes or within a gene. This mixture model's performance is evaluated in data analyses for two pharmacogenetics studies. In one example, thirty five CYP2D6 genotypes were partitioned into three groups to predict pharmacokinetics of a breast cancer drug, Tamoxifen, a CYP2D6 substrate (p-value = 0.04). In a second example, seventeen CYP2B6 genotypes were categorized into three clusters to predict CYP2B6 protein expression (p-value = 0.002). The biological validities of both partitions are examined using established function of CYP2D6 and CYP2B6 alleles. In both examples, we observed genotypes clustered in the same group to have high functional similarities. The power and recovery rate of the true partition for the mixture model approach are investigated in statistical simulation studies, where it outperforms another published method.

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Veiga, M. I., S. Asimus, P. E. Ferreira, J. P. Martins, I. Cavaco, V. Ribeiro, T. N. Hai, et al. "Pharmacogenomics of CYP2A6, CYP2B6, CYP2C19, CYP2D6, CYP3A4, CYP3A5 and MDR1 in Vietnam." European Journal of Clinical Pharmacology 65, no. 4 (November 1, 2008): 355–63. http://dx.doi.org/10.1007/s00228-008-0573-8.

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Shaheen, Magda, Amira Brown, Deyu Pan, and Katrina Schrode. "3547 Relationship between smoking and alcohol use status: variations in candidate genes associated with addiction and successful quitting smoking." Journal of Clinical and Translational Science 3, s1 (March 2019): 52. http://dx.doi.org/10.1017/cts.2019.125.

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OBJECTIVES/SPECIFIC AIMS: Previous studies showed that 52% of smokers were unsuccessful in quitting smoking. Smoking in alcoholics is 2-3 times that of the general population with 50%-80% of alcoholics smoking regularly. Studies have linked several genetic variants to addiction. We examined the relation between successful quitting smoking, alcohol use, and genetic data for CYP2A6, CYP2B6, DRD2, DRD1 and GABRB1 alleles. METHODS/STUDY POPULATION: We analyzed data from NHANES III 1988-1994 for socioeconomic factors, physical activity, body mass index (BMI), alcohol status, successful quit smoking, and genetic data for CYP2A6, CYP2B6, DRD2, DRD1 and GABRB1 alleles. Multivariate logistic regression was used to examine the association between successful quit smoking and genotypes adjusting for other variables. Data were analyzed using SAS version 9.3 (design & weight). RESULTS/ANTICIPATED RESULTS: Of the 2,269 smokers, 57% were current smokers, 35% were heavy drinkers, 24% were both smokers & heavy drinkers and 41% successfully quitted smoking. Successfully quit smoking was associated with CYP2A6 (rs28399433-TG) (adjusted odds ratio (AOR) = 3.6, 95% confidence interval (CI) = 1.1-11.9, p = 0.03), CYP2B6 (rs2279343-AA and AG) (AOR = 2.3, 95%CI = 1.5-3.5, p = 0.0003 for AA & AOR = 2.3, 95%CI = 1.2-4.2, p = 0.01 for AG) and DRD1 (rs4532-AA) (AOR = 2.2, 95%CI = 1.01-4.6, p = 0.04). Among heavy drinkers, those with CYP2A6 (rs28399433-TG) and CYP2B6 (rs2279343-AA and AG) were more likely to successfully quit smoking and those with CYP2A6 (rs5031017-GG) and GABRB1 (rs1442099-CC) were less likely to successfully quit smoking (p<0.05). DISCUSSION/SIGNIFICANCE OF IMPACT: We concluded that while rs28399433-TG, rs2279343-AA & AG positively impacted the success to quit smoking, rs5031017-GG & rs1442099-CC negatively impacted the success in quitting smoking both overall and specifically in heavy drinker smokers.

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Ayuso, Pedro, Megan Neary, Justin Chiong, and Andrew Owen. "Meta-analysis of the effect of CYP2B6, CYP2A6, UGT2B7 and CAR polymorphisms on efavirenz plasma concentrations." Journal of Antimicrobial Chemotherapy 74, no. 11 (August 1, 2019): 3281–90. http://dx.doi.org/10.1093/jac/dkz329.

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Abstract Background Efavirenz primary metabolism is catalysed by CYP2B6 with minor involvement of CYP2A6. Subsequently, phase I metabolites are conjugated by UGT2B7, and constitutive androstane receptor (CAR) has been shown to transcriptionally regulate many relevant enzymes and transporters. Several polymorphisms occurring in the genes coding for these proteins have been shown to impact efavirenz pharmacokinetics in some but not all studies. Objectives A meta-analysis was performed to assess the overall effect of CYP2B6 rs3745274, CYP2A6 (rs28399454, rs8192726 and rs28399433), UGT2B7 (rs28365062 and rs7439366) and NR1I3 (rs2307424 and rs3003596) polymorphisms on mid-dose efavirenz plasma concentrations. Methods Following a literature review, pharmacokinetic parameters were compiled and a meta-analysis for these variants was performed using Review Manager and OpenMetaAnalyst. A total of 28 studies were included. Results Unsurprisingly, the analysis confirmed that individuals homozygous for the T allele for CYP2B6 rs3745274 had significantly higher efavirenz concentrations than those homozygous for the G allele [weighted standard mean difference (WSMD) = 2.98; 95% CI 2.19–3.76; P < 0.00001]. A subgroup analysis confirmed ethnic differences in frequency but with a similar effect size in each ethnic group (P = 0.96). Associations with CYP2A6 and UGT2B7 variants were not statistically significant, but T homozygosity for CAR rs2307424 was associated with significantly lower efavirenz concentrations than in C homozygotes (WSMD = −0.32; 95% CI −0.59 to −0.06; P = 0.02). Conclusions This meta-analysis provides the overall effect size for the impact of CYP2B6 rs3745274 and NR1I3 rs2307424 on efavirenz pharmacokinetics. The analysis also indicates that some previous associations were not significant when interrogated across studies.

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Jacob, Robyn M., Elaine C. Johnstone, Matt J. Neville, and Robert T. Walton. "Identification of CYP2B6 Sequence Variants by Use of Multiplex PCR with Allele-Specific Genotyping." Clinical Chemistry 50, no. 8 (August 1, 2004): 1372–77. http://dx.doi.org/10.1373/clinchem.2004.031708.

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Abstract Background: Cytochrome P450 2B6 (CYP2B6) has a role in the metabolism of many clinically important substances, but the variation within the CYP2B6 gene has not been fully characterized. The aim of the present study was to develop a reliable and robust assay for determining genotypic variants. Methods: We used a two-stage procedure. An initial multiplex PCR reaction amplified the relevant gene fragments in exonic and regulatory regions to ensure isolation of CYP2B6 from its similar pseudogene (CYP2B7). This product was then genotyped by allele-specific PCR. Results: The assay detected the following published single-nucleotide polymorphisms: C64T (Arg22Cys), C78T, G216C, G516T (Gln172His), C777A (Ser259Arg), A785G (Lys262Arg), and C1459T (Arg487Cys), as well as additional loci found within the single-nucleotide polymorphism (SNP) databases: A1190G, C1268A, C1330T, A1382G, A1402T, and an A/T SNP in intron 2 (A12917T). This approach detected all common, previously reported alleles and identified a new allele (CYP2B6*4C) present in 2.2% of a Caucasian population. Genotypic frequencies obtained were consistent with previously published results. Conclusions: This method is simple, reliable, rapid, and amenable to automation and could facilitate the large-scale genotypic analysis of CYP2B6.

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Kharasch, Evan D., Karen J. Regina, Jane Blood, and Christina Friedel. "Methadone Pharmacogenetics." Anesthesiology 123, no. 5 (November 1, 2015): 1142–53. http://dx.doi.org/10.1097/aln.0000000000000867.

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Abstract Background Interindividual variability in methadone disposition remains unexplained, and methadone accidental overdose in pain therapy is a significant public health problem. Cytochrome P4502B6 (CYP2B6) is the principle determinant of clinical methadone elimination. The CYP2B6 gene is highly polymorphic, with several variant alleles. CYP2B6.6, the protein encoded by the CYP2B6*6 polymorphism, deficiently catalyzes methadone metabolism in vitro. This investigation determined the influence of CYP2B6*6, and other allelic variants encountered, on methadone concentrations, clearance, and metabolism. Methods Healthy volunteers in genotype cohorts CYP2B6*1/*1 (n = 21), CYP2B6*1/*6 (n = 20), and CYP2B6*6/*6 (n = 17), and also CYP2B6*1/*4 (n = 1), CYP2B6*4/*6 (n = 3), and CYP2B6*5/*5 (n = 2) subjects, received single doses of IV and oral methadone. Plasma and urine methadone and metabolite concentrations were determined by tandem mass spectrometry. Results Average S-methadone apparent oral clearance was 35 and 45% lower in CYP2B6*1/*6 and CYP2B6*6/*6 genotypes, respectively, compared with CYP2B6*1/*1. R-methadone apparent oral clearance was 25 and 35% lower in CYP2B6*1/*6 and CYP2B6*6/*6 genotypes, respectively, compared with CYP2B6*1/*1. R- and S-methadone apparent oral clearance was threefold and fourfold greater in CYP2B6*4 carriers. IV and oral R- and S-methadone metabolism was significantly lower in CYP2B6*6 carriers compared with that of CYP2B6*1 homozygotes and greater in CYP2B6*4 carriers. Methadone metabolism and clearance were lower in African Americans in part because of the CYP2B6*6 genetic polymorphism. Conclusions CYP2B6 polymorphisms influence methadone plasma concentrations, because of altered methadone metabolism and thus clearance. Genetic influence is greater for oral than IV methadone and S- than R-methadone. CYP2B6 pharmacogenetics explains, in part, interindividual variability in methadone elimination. CYP2B6 genetic effects on methadone metabolism and clearance may identify subjects at risk for methadone toxicity and drug interactions.

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Kim, Sunjoo, Dong Kyun Kim, Yongho Shin, Ji-Hyeon Jeon, Im-Sook Song, and Hye Suk Lee. "In Vitro Interaction of AB-FUBINACA with Human Cytochrome P450, UDP-Glucuronosyltransferase Enzymes and Drug Transporters." Molecules 25, no. 19 (October 8, 2020): 4589. http://dx.doi.org/10.3390/molecules25194589.

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AB-FUBINACA, a synthetic indazole carboxamide cannabinoid, has been used worldwide as a new psychoactive substance. Because drug abusers take various drugs concomitantly, it is necessary to explore potential AB-FUBINACA-induced drug–drug interactions caused by modulation of drug-metabolizing enzymes and transporters. In this study, the inhibitory effects of AB-FUBINACA on eight major human cytochrome P450s (CYPs) and six uridine 5′-diphospho-glucuronosyltransferases (UGTs) of human liver microsomes, and on eight clinically important transport activities including organic cation transporters (OCT)1 and OCT2, organic anion transporters (OAT)1 and OAT3, organic anion transporting polypeptide transporters (OATP)1B1 and OATP1B3, P-glycoprotein, and breast cancer resistance protein (BCRP) in transporter-overexpressing cells were investigated. AB-FUBINACA inhibited CYP2B6-mediated bupropion hydroxylation via mixed inhibition with Ki value of 15.0 µM and competitively inhibited CYP2C8-catalyzed amodiaquine N-de-ethylation, CYP2C9-catalyzed diclofenac 4′-hydroxylation, CYP2C19-catalyzed [S]-mephenytoin 4′-hydroxylation, and CYP2D6-catalyzed bufuralol 1′-hydroxylation with Ki values of 19.9, 13.1, 6.3, and 20.8 µM, respectively. AB-FUBINACA inhibited OCT2-mediated MPP+ uptake via mixed inhibition (Ki, 54.2 µM) and competitively inhibited OATP1B1-mediated estrone-3-sulfate uptake (Ki, 94.4 µM). However, AB-FUBINACA did not significantly inhibit CYP1A2, CYP2A6, CYP3A4, UGT1A1, UGT1A3, UGT1A4, UGT1A6, or UGT2B7 enzyme activities at concentrations up to 100 µM. AB-FUBINACA did not significantly inhibit the transport activities of OCT1, OAT1/3, OATP1B3, P-glycoprotein, or BCRP at concentrations up to 250 μM. As the pharmacokinetics of AB-FUBINACA in humans and animals remain unknown, it is necessary to clinically evaluate potential in vivo pharmacokinetic drug–drug interactions induced by AB-FUBINACA-mediated inhibition of CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, OCT2, and OATP1B1 activities.

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LEWIS, D. F. V., B. G. LAKE, M. DICKINS, P. J. EDDERSHAW, M. H. TARBIT, and P. S. GOLDFARB. "Molecular modelling of CYP2B6, the human CYP2B isoform, by homology with the substrate-bound CYP102 crystal structure: evaluation of CYP2B6 substrate characteristics, the cytochrome b5binding site and comparisons with CYP2B1 and CYP2B4." Xenobiotica 29, no. 4 (January 1999): 361–93. http://dx.doi.org/10.1080/004982599238560.

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Kurian, Ritika, William Hedrich, Bryan Mackowiak, Linhao Li, and Hongbing Wang. "CITCO as an Adjuvant Facilitates CHOP-Based Lymphoma Treatment in hCAR-Transgenic Mice." Cells 9, no. 11 (November 21, 2020): 2520. http://dx.doi.org/10.3390/cells9112520.

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Non-Hodgkin’s lymphoma (NHL) is a malignant cancer originating in the lymphatic system with a 25–30% mortality rate. CHOP, consisting of cyclophosphamide (CPA), doxorubicin, vincristine, and prednisone, is a first-generation chemotherapy extensively used to treat NHL. However, poor survival rates among patients in advanced stages of NHL shows a need to improve this standard of care treatment. CPA, an integral component of CHOP, is a prodrug that requires CYP2B6-mediated bioactivation to 4-hydroxy-CPA (4-OH-CPA). The expression of CYP2B6 is transcriptionally regulated by the constitutive androstane receptor (CAR, NRi13). We have previously demonstrated that the induction of hepatic CYP2B6 by CITCO, a selective human CAR (hCAR) agonist, results in CHOP’s enhanced antineoplastic effects in vitro. Here, we investigate the in vivo potential of CITCO as an adjuvant of CPA-based NHL treatment in a hCAR-transgenic mouse line. Our results demonstrate that the addition of CITCO to the CHOP regimen leads to significant suppression of the growth of EL-4 xenografts in hCAR-transgenic mice accompanied by reduced expression of cyclin-D1, ki67, Pcna, and increased caspase 3 fragmentation in tumor tissues. CITCO robustly induced the expression of cyp2b10 (murine ortholog of CYP2B6) through hCAR activation and increased plasma concentrations of 4-OH-CPA. Comparing to intraperitoneal injection, oral gavage of CITCO results in optimal hepatic cyp2b10 induction. Our in vivo studies have collectively uncovered CITCO as an effective facilitator for CPA-based NHL treatment with a pharmacokinetic profile favoring oral administration, promoting CITCO as a promising adjuvant candidate for CPA-based regimens.

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Kamal, Nik Nur Syazana Bt Nik Mohamed, Theam Soon Lim, Gee Jun Tye, Rusli Ismail, and Yee Siew Choong. "The Effect of CYP2B6, CYP2D6, and CYP3A4 Alleles on Methadone Binding: A Molecular Docking Study." Journal of Chemistry 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/249642.

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Current methadone maintenance therapy (MMT) is yet to ensure 100% successful treatment as the optimum dosage has yet to be determined. Overdose leads to death while lower dose causes the opioid withdrawal effect. Single-nucleotide polymorphisms (SNP) in cytochrome P450s (CYPs), the methadone metabolizers, have been showen to be the main factor for the interindividual variability of methadone clinical effects. In this study, we investigated the effect of SNPs in three major methadone metabolizers (CYP2B6, CYP2D6, and CYP3A4) on methadone binding affinity. Results showed thatCYP2B6*11,CYP2B6*12,CYP2B6*18, andCYP3A4*12have significantly higher binding affinity toR-methadone compared to wild type.S-methadone has higher binding affinity inCYP3A4*3,CYP3A4*11, andCYP3A4*12compared to wild type.R-methadone was shown to be the active form of methadone; thus individuals with CYP alleles that binds better toR-methadone will have higher methadone metabolism rate. Therefore, a higher dosage of methadone is necessary to obtain the opiate effect compared to a normal individual and vice versa. These results provide an initial prediction on methadone metabolism rate for individuals with mutant type CYP which enables prescription of optimum methadone dosage for individuals with CYP alleles.

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Mardi, Parham, Bahareh Tavakoli-Far, Samira Sheibani Nia, Roshanak Jazayeri, and Massoud Houshmand. "Frequency of CYP2B6 Alleles in Major Iranian Ethnicities, Affecting Response to Efavirenz." Genetics Research 2022 (October 19, 2022): 1–10. http://dx.doi.org/10.1155/2022/5754776.

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Introduction. Efavirenz is an antihuman immunodeficiency virus (HIV) drug metabolized by cytochrome P450 2B6 (CYP2B6) enzyme. Cytochrome P450 2B6 is an enzyme that in humans is encoded by the CYP2B6 gene. Polymorphisms of this gene play a crucial role in the metabolism of drugs such as Efavirenz. This study aims to evaluate the frequency of three clinically significant CYP2B6 polymorphisms (CYP2B6 ∗ 6 (516G > T), CYP2B6 ∗ 4 (785A > G), and CYP2B6 ∗ 5 (1459C > T)) in three major Iranian ethnicities. Methods. One hundred forty-seven participants from three main Iranian ethnicities were included in this study. After DNA extraction, CYP2B6 ∗ 6 (516G > T), CYP2B6 ∗ 4 (785A > G), and CYP2B6 ∗ 5 (1459C > T) were genotyped using tetra-primer amplification refractory mutation system polymerase chain reaction (ARMS-PCR). Results. The frequency of the mutated allele in the Iranian population for CYP2B6 ∗ 6 (516G > T) was 41.50 (95% CI: 35.81, 47.36), which was significantly lower than in Kurds (59.62, 95% CI: 45.10, 72.99). Similarly, Kurds had a higher frequency of mutated allele of CYP2B6 ∗ 5 (1459C > T) (46.15%, 95% CI: 32.23, 60.53) than in Iranians (24.49%, 95% CI: 19.68, 29.82). The frequency of A and G alleles of CYP2B6 ∗ 4 (785A > G) was 62.59% (95% CI: 56.78, 68.13) and 37.41 (95% CI: 31.87, 43.22), respectively. Conclusion. Kurds are at higher risk of adverse drug reactions (ADRs) and insufficient anti-HIV response compared to other Iranians.

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Rao, Lesley K., Alicia M. Flaker, Christina C. Friedel, and Evan D. Kharasch. "Role of Cytochrome P4502B6 Polymorphisms in Ketamine Metabolism and Clearance." Anesthesiology 125, no. 6 (December 1, 2016): 1103–12. http://dx.doi.org/10.1097/aln.0000000000001392.

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Abstract Background At therapeutic concentrations, cytochrome P4502B6 (CYP2B6) is the major P450 isoform catalyzing hepatic ketamine N-demethylation to norketamine in vitro. The CYP2B6 gene is highly polymorphic. The most common variant allele, CYP2B6*6, is associated with diminished hepatic CYP2B6 expression and catalytic activity compared with wild-type CYP2B6*1/*1. CYP2B6.6, the protein encoded by the CYP2B6*6 allele, and liver microsomes from CYP2B6*6 carriers had diminished ketamine metabolism in vitro. This investigation tested whether humans with the CYP2B6*6 allele would have decreased clinical ketamine metabolism and clearance. Methods Thirty volunteers with CYP2B6*1/*1, *1/*6, or *6/*6 genotypes (n = 10 each) received a subsedating dose of oral ketamine. Plasma and urine concentrations of ketamine and the major CYP2B6-dependent metabolites were determined by mass spectrometry. Subjects’ self-assessment of ketamine effects were also recorded. The primary outcome was ketamine N-demethylation, measured as the plasma norketamine/ketamine area under the curve ratio. Secondary outcomes included plasma ketamine enantiomer and metabolite area under the plasma concentration–time curve, maximum concentrations, apparent oral clearance, and metabolite formation clearances. Results There was no significant difference between CYP2B6 genotypes in ketamine metabolism or any of the secondary outcome measures. Subjective self-assessment did reveal some differences in energy and level of awareness among subjects. Conclusions These results show that while the CYP2B6*6 polymorphism results in diminished ketamine metabolism in vitro, this allelic variant did not affect single, low-dose ketamine metabolism, clearance, and pharmacokinetics in vivo. While in vitro drug metabolism studies may be informative, clinical investigations in general are needed to validate in vitro observations.

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McLaughlin, Poppy, Cheryl Gillis, Michael Osselton, and Helen Mactier. "Variations in Infant CYP2B6 Genotype Associated with the Need for Pharmacological Treatment for Neonatal Abstinence Syndrome in Infants of Methadone-Maintained Opioid-Dependent Mothers." American Journal of Perinatology 34, no. 09 (March 20, 2017): 918–21. http://dx.doi.org/10.1055/s-0037-1600917.

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Background Neonatal abstinence syndrome (NAS) in infants of methadone-maintained opioid-dependent (MMOD) mothers cannot be predicted in individual cases. We investigated whether variation in infant genotype is associated with severity of NAS. Methods This is a pilot observational cohort study of 21 MMOD mothers and their newborns. Infant buccal swabs were obtained soon after delivery, together with a maternal blood sample for the determination of maternal plasma methadone concentration. Genomic variation in five opioid-related genes (ABCB1, COMT, CYP2B6, CYP2D6, and OPRM1) was ascertained from infant buccal swabs and related to need for pharmacological treatment of NAS. Results Out of 21 infants, 11 (52%) required treatment for NAS. Mothers of treated infants tended to have been prescribed higher doses of methadone, but plasma methadone concentrations did not differ between mothers of treated or untreated babies. Treated and untreated babies did not differ in terms of method of feeding. Treated infants were more likely to carry the normal (homozygous) allele at 516 and 785 regions of CYP2B6 gene (p = 0.015 and 0.023, respectively). There were no differences in any other genes between infants who did or did not require treatment for NAS. Conclusion Genomic variation in CYP2B6 may explain, at least in part, severity of NAS.

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Wang, Xianqin, Mengchun Chen, Xinxin Chen, Jianshe Ma, Congcong Wen, Jianchun Pan, Lufeng Hu, and Guanyang Lin. "The Effects of Acute Hydrogen Sulfide Poisoning on Cytochrome P450 Isoforms Activity in Rats." BioMed Research International 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/209393.

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Hydrogen sulfide (H2S) is the second leading cause of toxin related death (after carbon monoxide) in the workplace. H2S is absorbed by the upper respiratory tract mucosa, and it causes histotoxic hypoxemia and respiratory depression. Cocktail method was used to evaluate the influences of acute H2S poisoning on the activities of cytochrome P450 isoforms CYP2B6, CYP2D6, CYP3A4, CYP1A2, CYP2C19, and CYP2C9, which were reflected by the changes of pharmacokinetic parameters of six specific probe drugs, bupropion, metoprolol, midazolam, phenacetin, omeprazole, and tolbutamide, respectively. The experimental rats were randomly divided into two groups, control group and acute H2S poisoning group (inhaling 300 ppm for 2 h). The mixture of six probes was given to rats by 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. The results for acute H2S poisoning and control groups were as follows: there was a statistically significant difference in the AUC andCmaxfor bupropion, metoprolol, phenacetin, and tolbutamide, while there was no statistical pharmacokinetic difference for midazolam and omeprazole. Acute H2S poisoning could inhibit the activity of CYP2B6, CYP2D6, CYP1A2, and CYP2C9 in rats.

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Gervot, L., B. Rochat, J. C. Gautier, F. Bohnenstengel, H. Kroemer, V. de Berardinis, H. Martin, P. Beaune, and I. de Waziers. "Human CYP2B6." Pharmacogenetics 9, no. 3 (June 1999): 295–306. http://dx.doi.org/10.1097/00008571-199906000-00004.

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Wang, Pan-Fen, Alicia Neiner, and Evan D. Kharasch. "Stereoselective Ketamine Metabolism by Genetic Variants of Cytochrome P450 CYP2B6 and Cytochrome P450 Oxidoreductase." Anesthesiology 129, no. 4 (October 1, 2018): 756–68. http://dx.doi.org/10.1097/aln.0000000000002371.

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Abstract Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New Background Human ketamine N-demethylation to norketamine in vitro at therapeutic concentrations is catalyzed predominantly by the cytochrome P4502B6 isoform (CYP2B6). The CYP2B6 gene is highly polymorphic. CYP2B6.6, the protein encoded by the common variant allele CYP2B6*6, exhibits diminished ketamine metabolism in vitro compared with wild-type CYP2B6.1. The gene for cytochrome P450 oxidoreductase (POR), an obligatory P450 coenzyme, is also polymorphic. This investigation evaluated ketamine metabolism by genetic variants of human CYP2B6 and POR. Methods CYP2B6 (and variants), POR (and variants), and cytochrome b5 (wild-type) were coexpressed in a cell system. All CYP2B6 variants were expressed with wild-type POR and b5. All POR variants were expressed with wild-type CYP2B6.1 and b5. Metabolism of R- and S-ketamine enantiomers, and racemic RS-ketamine to norketamine enantiomers, was determined using stereoselective high-pressure liquid chromatography–mass spectrometry. Michaelis–Menten kinetic parameters were determined. Results For ketamine enantiomers and racemate, metabolism (intrinsic clearance) was generally wild-type CYP2B6.1 > CYP2B6.4 > CYP2B6.26, CYP2B6.19, CYP2B6.17, CYP2B6.6 > CYP2B6.5, CYP2B6.7 > CYP2B6.9. CYP2B6.16 and CYP2B6.18 were essentially inactive. Activity of several CYP2B6 variants was less than half that of CYP2B6.1. CYP2B6.9 was 15 to 35% that of CYP2B6.1. The order of metabolism was wild-type POR.1 > POR.28, P228L > POR.5. CYP2B6 variants had more influence than POR variants on ketamine metabolism. Neither CYP2B6 nor POR variants affected the stereoselectivity of ketamine metabolism (S > R). Conclusions Genetic variants of CYP2B6 and P450 oxidoreductase have diminished ketamine N-demethylation activity, without affecting the stereoselectivity of metabolism. These results suggest candidate genetic polymorphisms of CYP2B6 and P450 oxidoreductase for clinical evaluation to assess consequences for ketamine pharmacokinetics, elimination, bioactivation, and therapeutic effects.

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Puttrevu, Santosh Kumar, Sumit Arora, Sebastian Polak, and Nikunj Kumar Patel. "Physiologically Based Pharmacokinetic Modeling of Transdermal Selegiline and Its Metabolites for the Evaluation of Disposition Differences between Healthy and Special Populations." Pharmaceutics 12, no. 10 (September 30, 2020): 942. http://dx.doi.org/10.3390/pharmaceutics12100942.

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A physiologically based pharmacokinetic (PBPK) model of selegiline (SEL), and its metabolites, was developed in silico to evaluate the disposition differences between healthy and special populations. SEL is metabolized to methamphetamine (MAP) and desmethyl selegiline (DMS) by several CYP enzymes. CYP2D6 metabolizes the conversion of MAP to amphetamine (AMP), while CYP2B6 and CYP3A4 predominantly mediate the conversion of DMS to AMP. The overall prediction error in simulated PK, using the developed PBPK model, was within 0.5–1.5-fold after intravenous and transdermal dosing in healthy and elderly populations. Simulation results generated in the special populations demonstrated that a decrease in cardiac output is a potential covariate that affects the SEL exposure in renally impaired (RI) and hepatic impaired (HI) subjects. A decrease in CYP2D6 levels increased the systemic exposure of MAP. DMS exposure increased due to a reduction in the abundance of CYP2B6 and CYP3A4 in RI and HI subjects. In addition, an increase in the exposure of the primary metabolites decreased the exposure of AMP. No significant difference between the adult and adolescent populations, in terms of PK, were observed. The current PBPK model predictions indicate that subjects with HI or RI may require closer clinical monitoring to identify any untoward effects associated with the administration of transdermal SEL patch.

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Hammond, Timothy G., and Holly H. Birdsall. "Hepatocyte CYP2B6 Can Be Expressed in Cell Culture Systems by Exerting Physiological Levels of Shear: Implications for ADME Testing." Journal of Toxicology 2017 (2017): 1–5. http://dx.doi.org/10.1155/2017/1907952.

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Cytochrome 2B6 (CYP2B6) has substantial clinical effects on morbidity and mortality and its effects on drug metabolism should be part of hepatotoxicity screening. Examples of CYP2B6’s impacts include its linkage to mortality during cyclophosphamide therapy and its role in determining hepatotoxicity and CNS toxicity during efavirenz therapy for HIV infection. CYP2B6 is key to metabolism of many common drugs from opioids to antidepressants, anesthetics, and anticonvulsants. But CYP2B6 has been extremely difficult to express in cell culture, and as a result, it has been largely deemphasized in preclinical toxicity studies. It has now been shown that CYP2B6 expression can be supported for extended periods of time using suspension culture techniques that exert physiological levels of shear. New understanding of CYP2B6 has identified five clinically significant genetic polymorphisms that have a high incidence in many populations and that convey a substantial dynamic range of activity. We propose that, with the use of culture devices exerting physiological shear levels, CYP2B6 dependent drug testing, including definition of polymorphisms and application of specific inhibitors, should be a standard part of preclinical absorption, distribution, metabolism, and excretion (ADME) testing.

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Rotger, Margalida, Maria Saumoy, Kunlin Zhang, Markus Flepp, Roland Sahli, Laurent Decosterd, and Amalio Telenti. "Partial deletion of CYP2B6 owing to unequal crossover with CYP2B7." Pharmacogenetics and Genomics 17, no. 10 (October 2007): 885–90. http://dx.doi.org/10.1097/fpc.0b013e3282ef5cd1.

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Ring, Huijun Z., Ana M. Valdes, Denise M. Nishita, Suman Prasad, Peyton Jacob, Rachel F. Tyndale, Gary E. Swan, and Neal L. Benowitz. "Gene???gene interactions between CYP2B6 and CYP2A6 in nicotine metabolism." Pharmacogenetics and Genomics 17, no. 12 (December 2007): 1007–15. http://dx.doi.org/10.1097/01.fpc.0000220560.59972.33.

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Marok, Fatima Zahra, Laura Maria Fuhr, Nina Hanke, Dominik Selzer, and Thorsten Lehr. "Physiologically Based Pharmacokinetic Modeling of Bupropion and Its Metabolites in a CYP2B6 Drug-Drug-Gene Interaction Network." Pharmaceutics 13, no. 3 (March 4, 2021): 331. http://dx.doi.org/10.3390/pharmaceutics13030331.

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The noradrenaline and dopamine reuptake inhibitor bupropion is metabolized by CYP2B6 and recommended by the FDA as the only sensitive substrate for clinical CYP2B6 drug–drug interaction (DDI) studies. The aim of this study was to build a whole-body physiologically based pharmacokinetic (PBPK) model of bupropion including its DDI-relevant metabolites, and to qualify the model using clinical drug–gene interaction (DGI) and DDI data. The model was built in PK-Sim® applying clinical data of 67 studies. It incorporates CYP2B6-mediated hydroxylation of bupropion, metabolism via CYP2C19 and 11β-HSD, as well as binding to pharmacological targets. The impact of CYP2B6 polymorphisms is described for normal, poor, intermediate, and rapid metabolizers, with various allele combinations of the genetic variants CYP2B6*1, *4, *5 and *6. DDI model performance was evaluated by prediction of clinical studies with rifampicin (CYP2B6 and CYP2C19 inducer), fluvoxamine (CYP2C19 inhibitor) and voriconazole (CYP2B6 and CYP2C19 inhibitor). Model performance quantification showed 20/20 DGI ratios of hydroxybupropion to bupropion AUC ratios (DGI AUCHBup/Bup ratios), 12/13 DDI AUCHBup/Bup ratios, and 7/7 DDGI AUCHBup/Bup ratios within 2-fold of observed values. The developed model is freely available in the Open Systems Pharmacology model repository.

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Mirzaev, K. B., D. S. Fedorinov, D. V. Ivashchenko, and D. A. Sychev. "Multi-Ethnic Analysis of Cardiac Pharmacogenetic Markers of Cytochrome P450 and Membrane Transporters Genes in the Russian Population." Rational Pharmacotherapy in Cardiology 15, no. 3 (July 6, 2019): 393–406. http://dx.doi.org/10.20996/1819-6446-2019-15-3-393-406.

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Aim. To summarize Russian studies using pharmacogenetic testing as applied to cardiology.Material and methods. The authors conducted an online search for articles in December 2018 using the following databases: PubMed, Google Scholar, eLIBRARY. The search was carried out by keywords: "Russia", "Russian", "cardiology" together with the terms associated with the polymorphic marker, including: «P450», «CYP2C19», «CYP2D6», «CYP2B1», «CYP2B6», «CYP2Е1», «CYP2C8», «CYP2C9», «CYP3A4», «CYP3A5», «CYP1A1», «CYP1A2», «CYP4F2», «CYP4F1», «ABCB1», «SLCO1B1», «VKORC1», «GGCX», «SULT1A1», «CULT1», «CES1», «gene», «genes», «pharmacogenetics», «pharmacogenomics», «ethnic group».Results. Generalization of information allowed to identify obscure genes that need to be investigated in pharmacogenetic studies. This information can be used for the development of dosing algorithms and the priority choice of drugs, considering the results of pharmacogenetic testing and planning future research.Conclusion. The results of the literature review indicate the importance of studying the most clinically valid and clinically useful pharmacogenetic markers (CYP2C19, CYP2C9, VKORC1, SLCO1B1) among various ethnic groups in the Russian Federation. With the accumulation of evidence of clinical validity and clinical utility of other pharmacogenetic markers (CES1, CYP2D6*4, etc.), the problem of interethnic differences in the carriage of clinically significant polymorphisms of these genes identified in previous studies in the Russian Federation increasingly requires attention. The most promising for the introduction into the clinical practice in the Russian Federation in the near future are polymorphic markers of the CYP2C19, CYP2C9, VKORC1 and SLCO1B1 genes.

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Desta, Zeruesenay, Ahmed El‐Boraie, Li Gong, Andrew A. Somogyi, Volker M. Lauschke, Collet Dandara, Kathrin Klein, et al. "PharmVar GeneFocus: CYP2B6." Clinical Pharmacology & Therapeutics 110, no. 1 (March 11, 2021): 82–97. http://dx.doi.org/10.1002/cpt.2166.

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Li, Huijie, Qiang Wang, Suyun Li, and Chongqi Jia. "Effects of Genetic Variants in the Nicotine Metabolism Pathway on Smoking Cessation." Genetics Research 2022 (September 28, 2022): 1–9. http://dx.doi.org/10.1155/2022/2917881.

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Background. We aimed to investigate the associations of various genetic variants in the nicotine metabolism pathway with smoking cessation (SC) in the Chinese Han population. Method. A case-control study was conducted where 363 successful smoking quitters were referred to as cases, and 345 failed smoking quitters were referred to as controls. A total of 42 genetic variants in 10 genes were selectedand genotyped. The weighted gene score was applied to analyze the whole gene effect. Logistic regression was used to explore associations of each genetic variant and gene score with smoking cessation. Results. Our study found that the variants CYP2A6 ∗ 4, rs11726322, rs12233719, and rs3100 were associated with a higher probability of quitting smoking, while rs3760657 was associated with a lower probability of quitting smoking. Moreover, the gene scores of CYP2D6, FMO3, UGT2B10, UGT1A9, UGT2B7, and UGT2B15 were shown to exert a positive effect, while the gene score of CYP2B6 was detected to exert a negative effect on successful smoking cessation. Conclusion. This study revealed that genetic variants in the nicotine metabolic pathway were associated with smoking cessation in the Chinese Han population.

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Chou, Monidarin, Julie Bertrand, Olivier Segeral, Céline Verstuyft, Laurence Borand, Emmanuelle Comets, Clotilde Le Tiec, et al. "Population Pharmacokinetic-Pharmacogenetic Study of Nevirapine in HIV-Infected Cambodian Patients." Antimicrobial Agents and Chemotherapy 54, no. 10 (August 9, 2010): 4432–39. http://dx.doi.org/10.1128/aac.00512-10.

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ABSTRACT The aims of this ANRS12154 open-label, single-center, multiple-dose pharmacokinetic study were to characterize nevirapine pharmacokinetics in a Cambodian population of HIV-infected patients and to identify environmental and genetic factors of variability, focusing on the CYP2B6, CYP3A5, and ABCB1 (MDR1) genes. A total of 170 Cambodian HIV-infected patients were included. Nevirapine trough concentrations were measured after 18 and 36 months of starting antiretroviral treatment and in samples drawn during a dosing interval in a subset of 10 patients. All data were analyzed by nonlinear mixed-effects modeling. The effect of covariates was investigated using the population pharmacokinetic model. Patients carrying homozygous loss-of-function alleles CYP3A5 6986A>G, CYP2B6 516G>T, CYP2B6 1459C>T, and ABCB1 3435C>T represent 42.4%, 9.2%, 0%, and 18% of the population, respectively. The median nevirapine trough concentrations did not differ after 18 and 36 months of treatment (5,705 ng/ml [range, ≤50 to 13,871] and 5,709 ng/ml [range, ≤50 to 15,422], respectively). Interpatient and intrapatient variabilities of nevirapine apparent clearance were 28% and 17%, respectively. CYP2B6 516G>T and creatinine clearance were found to significantly affect nevirapine apparent clearance. The estimated nevirapine apparent clearances were 2.95 liters/h, 2.62 liters/h, and 1.86 liters/h for CYP2B6 516GG, CYP2B6 516GT, and CYP2B6 516TT genotypes, respectively. The impact of creatinine clearance was small. This study demonstrates that 95% of the patients had sustained nevirapine exposure well above the 3,000-ng/ml threshold. Nevirapine clearance was shown to be affected by CYP2B6 516G>T genetic polymorphism and creatinine clearance, although this explained only part of the interpatient variability, which remains low compared to that for other antiretroviral drugs.

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Yu, Jun, Min Choi, Jong Park, Shaheed Rehman, Katsunori Nakamura, and Hye Yoo. "Inhibitory Effects of Garcinia cambogia Extract on CYP2B6 Enzyme Activity." Planta Medica 83, no. 11 (March 13, 2017): 895–900. http://dx.doi.org/10.1055/s-0043-104934.

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AbstractThis study assessed the inhibitory effects of Garcinia cambogia extract on the cytochrome P450 enzymes in vitro. G. cambogia extract was incubated with cytochrome P450 isozyme-specific substrates in human liver microsomes and recombinant CYP2B6 isozyme, and the formation of the marker metabolites was measured to investigate the inhibitory potential on cytochrome P450 enzyme activities. The results showed that G. cambogia extract has significant inhibitory effects on CYP2B6 activity in a concentration-dependent manner. Furthermore, the inhibition was potentiated following preincubation with NADPH, indicating that G. cambogia extract is a time-dependent inhibitor of CYP2B6. Meanwhile, hydroxycitric acid, the major bioactive ingredient of G. cambogia extract, did not exhibit significant inhibition effects on cytochrome P450 enzyme activities. G. cambogia extract could modulate the pharmacokinetics of CYP2B6 substrate drugs and lead to interactions with those drugs. Therefore, caution may be required with respect to concomitant intake of dietary supplements containing G. cambogia extract with CYP2B6 substrates.

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Altieri, Barbara, Silviu Sbiera, Sabine Herterich, Silvia De Francia, Silvia Della Casa, Anna Calabrese, Alfredo Pontecorvi, et al. "Effects of Germline CYP2W1*6 and CYP2B6*6 Single Nucleotide Polymorphisms on Mitotane Treatment in Adrenocortical Carcinoma: A Multicenter ENSAT Study." Cancers 12, no. 2 (February 4, 2020): 359. http://dx.doi.org/10.3390/cancers12020359.

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Mitotane is the only approved drug for advanced adrenocortical carcinoma (ACC) and no biomarkers are available to predict attainment of therapeutic plasma concentrations and clinical response. Aim of the study was to evaluate the suitability of cytochrome P450(CYP)2W1 and CYP2B6 single nucleotide polymorphisms (SNPs) as biomarkers. A multicenter cohort study including 182 ACC patients (F/M = 121/61) treated with mitotane monotherapy after radical resection (group A, n = 103) or in not completely resectable, recurrent or advanced disease (group B, n = 79) was performed. CYP2W1*2, CYP2W1*6, CYP2B6*6 and CYP2B6 rs4803419 were genotyped in germline DNA. Mitotane blood levels were measured regularly. Response to therapy was evaluated as time to progression (TTP) and disease control rate (DCR). Among investigated SNPs, CYP2W1*6 and CYP2B6*6 correlated with mitotane treatment only in group B. Patients with CYP2W1*6 (n = 21) achieved less frequently therapeutic mitotane levels (>14 mg/L) than those with wild type (WT) allele (76.2% vs 51.7%, p = 0.051) and experienced shorter TTP (HR = 2.10, p = 0.019) and lower DCR (chi-square = 6.948, p = 0.008). By contrast, 55% of patients with CYP2B6*6 vs. 28.2% WT (p = 0.016) achieved therapeutic range. Combined, a higher rate of patients with CYP2W1*6WT+CYP2B6*6 (60.6%) achieved mitotane therapeutic range (p = 0.034). In not completely resectable, recurrent or advanced ACC, CYP2W1*6 SNP was associated with a reduced probability to reach mitotane therapeutic range and lower response rates, whereas CYP2B6*6 correlated with higher mitotane levels. The association of these SNPs may predict individual response to mitotane.

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Sridar, Chitra, Natasha T. Snider, and Paul F. Hollenberg. "Anandamide Oxidation by Wild-Type and Polymorphically Expressed CYP2B6 and CYP2D6." Drug Metabolism and Disposition 39, no. 5 (February 2, 2011): 782–88. http://dx.doi.org/10.1124/dmd.110.036707.

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Miyazawa, M., and K. Gyoubu. "Metabolism of (−)-fenchone by CYP2A6 and CYP2B6 in human liver microsomes." Xenobiotica 37, no. 2 (February 2007): 194–204. http://dx.doi.org/10.1080/00498250600917256.

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Miyazawa, Mitsuo, and Kunihiko Gyoubu. "Metabolism of (+)-Fenchone by CYP2A6 and CYP2B6 in Human Liver Microsomes." Biological & Pharmaceutical Bulletin 29, no. 12 (2006): 2354–58. http://dx.doi.org/10.1248/bpb.29.2354.

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Peko, Simon M., Félix Koukouikila-Koussounda, Madinga Kosso Etokabeka, Nerly Gueye Gampio, Simon Ch Kobawila, Christevy Vouvoungui, Laure S Linguissi Ghoma, David Nderu, Thirumalaisamy P. Velavan, and Francine Ntoumi. "PO 8261 CYTOCHROME P450 (CYP2B6*6C.516G>T) VARIANTS IN CONGOLESE INDIVIDUALS WITH HIV AND TB MONO AND DUAL INFECTIONS." BMJ Global Health 4, Suppl 3 (April 2019): A24.2—A24. http://dx.doi.org/10.1136/bmjgh-2019-edc.61.

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BackgroundThe inter-individual genetic polymorphism of cytochrome P450 enzymes (CYP), involved in the metabolism of many drugs, partly modulates drug response and toxicity. Single nucleotide polymorphisms of CYP2B6 for example, G516T have been implicated in high- and sub-therapeutic plasma concentration of the current antimalarial, HIV and TB first-line drugs in various geographical regions and thus undermines effective disease management. At present, there is no data on the frequency of CYP2B6 c.516G>T among the Congolese population, despite a significant number of people undergoing antimalarial, HIV and TB treatment that relies on CYP2B6-based drug clearance or activation.MethodsA total of 418 patients with HIV-1 mono-infection, HIV-1 +TB coinfection and P. falciparum infection were genotyped for CYP2B6 c.516G>T polymorphism using PCR-RFLP. The frequencies of the alleles as well as the genotypes (GG, GT and TT) were determined.ResultsThe frequency of CYP2B6 c.516G>T polymorphism was 69% and frequency of G and T alleles were 45% and 55%, respectively. 17.0% (49/288) of participants were GG (extensive metaboliser), 55.2% (159/288) of participants were GT (intermediate metaboliser) and 27.8% (80/288) of participants were TT (poor metabolisers).ConclusionThis study highlights CYP2B6 c.G516T polymorphism as a potential determinant of drug response and toxicity among the Congolese population, particularly those undergoing antiretroviral, malaria and tuberculosis treatment within the current first-line drug policy framework.

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Desta, Zeruesenay, Ingrid F. Metzger, Nancy Thong, Jessica B. L. Lu, John T. Callaghan, Todd C. Skaar, David A. Flockhart, and Raymond E. Galinsky. "Inhibition of Cytochrome P450 2B6 Activity by Voriconazole Profiled Using Efavirenz Disposition in Healthy Volunteers." Antimicrobial Agents and Chemotherapy 60, no. 11 (September 6, 2016): 6813–22. http://dx.doi.org/10.1128/aac.01000-16.

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ABSTRACTCytochrome P450 2B6 (CYP2B6) metabolizes clinically important drugs and other compounds. Its expression and activity vary widely among individuals, but quantitative estimation is hampered by the lack of safe and selectivein vivoprobes of CYP2B6 activity. Efavirenz, a nonnucleoside HIV-1 reverse transcriptase inhibitor, is mainly cleared by CYP2B6, an enzyme strongly inhibitedin vitroby voriconazole. To test efavirenz metabolism as anin vivoprobe of CYP2B6 activity, we quantified the inhibition of CYP2B6 activity by voriconazole in 61 healthy volunteers administered a single 100-mg oral dose of efavirenz with and without voriconazole administration. The kinetics of efavirenz metabolites demonstrated formation rate-limited elimination. Compared to control, voriconazole prolonged the elimination half-life (t1/2) and increased both the maximum concentration of drug in serum (Cmax) and the area under the concentration-time curve from 0 h tot(AUC0–t) of efavirenz (mean change of 51%, 36%, and 89%, respectively) (P< 0.0001) with marked intersubject variability (e.g., the percent change in efavirenz AUC0–tranged from 0.4% to ∼224%). Voriconazole decreased efavirenz 8-hydroxylation by greater than 60% (P< 0.0001), whereas its effect on 7-hydroxylation was marginal. The plasma concentration ratio of efavirenz to 8-hydroxyefavirenz, determined 1 to 6 h after dosing, was significantly increased by voriconazole and correlated with the efavirenz AUC0–t(Pearsonr= >0.8;P< 0.0001). This study demonstrates the mechanisms of voriconazole-efavirenz interaction, establishes the use of a low dose of efavirenz as a safe and selectivein vivoprobe for phenotyping CYP2B6 activity, and identifies several easy-to-use indices that should enhance understanding of the mechanisms of CYP2B6 interindividual variability. (This study is registered at ClinicalTrials.gov under identifier NCT01104376.)

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Court, Michael H., Su X. Duan, Leah M. Hesse, Karthik Venkatakrishnan, and David J. Greenblatt. "Cytochrome P-450 2B6 Is Responsible for Interindividual Variability of Propofol Hydroxylation by Human Liver Microsomes." Anesthesiology 94, no. 1 (January 1, 2001): 110–19. http://dx.doi.org/10.1097/00000542-200101000-00021.

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Background Oxidation of propofol to 4-hydroxypropofol represents a significant pathway in the metabolism of this anesthetic agent in humans. The aim of this study was to identify the principal cytochrome P-450 (CYP) isoforms mediating this biotransformation. Methods Propofol hydroxylation activities and enzyme kinetics were determined using human liver microsomes and cDNA-expressed CYPs. CYP-specific marker activities and CYP2B6 protein content were also quantified in hepatic microsomes for correlational analyses. Finally, inhibitory antibodies were used to ascertain the relative contribution of CYPs to propofol hydroxylation by hepatic microsomes. Results Propofol hydroxylation by hepatic microsomes showed more than 19-fold variability and was most closely correlated to CYP2B6 protein content (r = 0.904), and the CYP2B6 marker activities, S-mephenytoin N-demethylation (r = 0.919) and bupropion hydroxylation (r = 0.854). High- and intermediate-activity livers demonstrated high-affinity enzyme kinetics (K(m) < 8 microm), whereas low-activity livers displayed low-affinity kinetics (K(m) > 80 microm). All of the CYPs evaluated were capable of hydroxylating propofol; however, CYP2B6 and CYP2C9 were most active. Kinetic analysis indicated that CYP2B6 is a high-affinity (K(m) = 10 +/- 2 microm; mean +/- SE of the estimate), high-capacity enzyme, whereas CYP2C9 is a low-affinity (K(m) = 41 +/- 8 microm), high-capacity enzyme. Furthermore, immunoinhibition showed a greater contribution of CYP2B6 (56 +/- 22% inhibition; mean +/- SD) compared with CYP2C isoforms (16 +/- 7% inhibition) to hepatic microsomal activity. Conclusions Cytochrome P-450 2B6, and to a lesser extent CYP2C9, contribute to the oxidative metabolism of propofol. However, CYP2B6 is the principal determinant of interindividual variability in the hydroxylation of this drug by human liver microsomes.

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Packiasabapathy, Senthil, Blessed W. Aruldhas, Pengyue Zhang, Brian R. Overholser, Sara K. Quinney, and Senthilkumar Sadhasivam. "Novel associations between CYP2B6 polymorphisms, perioperative methadone metabolism and clinical outcomes in children." Pharmacogenomics 22, no. 10 (July 2021): 591–602. http://dx.doi.org/10.2217/pgs-2021-0039.

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Aim: Methadone exhibits significant variability in clinical response. This study explores the genetic influence of variable methadone pharmacokinetics. Methods: This is a prospective study of methadone in children undergoing major surgery. CYP2B6 genotyping, plasma methadone and metabolite levels were obtained. Clinical outcomes include pain scores and postoperative nausea and vomiting (PONV). Results: CYP2B6 poor metabolizers (*6/*6) had >twofold lower methadone metabolism compared with normal/rapid metabolizers. The incidence of PONV was 4.7× greater with CYP2B6 rs1038376 variant. AG/GG variants of rs2279343 SNP had 2.86-fold higher incidence of PONV compared with the wild variant ( AA). Nominal associations between rs10500282, rs11882424, rs4803419 and pain scores were observed. Conclusion: We have described novel associations between CYP2B6 genetic variants and perioperative methadone metabolism, and associations with pain scores and PONV.

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Inoue, Kaoru, Christoph H. Borchers, and Masahiko Negishi. "Cohesin protein SMC1 represses the nuclear receptor CAR-mediated synergistic activation of a human P450 gene by xenobiotics." Biochemical Journal 398, no. 1 (July 27, 2006): 125–33. http://dx.doi.org/10.1042/bj20060109.

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CAR (constitutive active/androstane receptor) regulates both the distal enhancer PBREM (phenobarbital-responsive enhancer module) and the proximal element OARE [OA (okadaic acid) response element] to synergistically up-regulate the endogenous CYP2B6 (where CYP is cytochrome P450) gene in HepG2 cells. In this up-regulation, CAR acts as both a transcription factor and a co-regulator, directly binding to and enhancing PBREM upon activation by xenobiotics such as TCPOBOP {1,4-bis-[2-(3,5-dichloropyridyloxy)]benzene} and indirectly associating with the OARE in response to OA [Swales, Kakizaki, Yamamoto, Inoue, Kobayashi and Negishi (2005) J. Biol. Chem. 280, 3458–3466]. We have now identified the cohesin protein SMC1 (structural maintenance of chromosomes 1) as a CAR-binding protein and characterized it as a negative regulator of OARE activity, thus repressing synergy. Treatment with SMC1 small interfering RNA augmented the synergistic up-regulation of CYP2B6 expression 20-fold in HepG2 cells, while transient co-expression of spliced form of SMC1 abrogated the synergistic activation of a 1.8 kb CYP2B6 promoter. SMC1 indirectly binds to a 19 bp sequence (−236/−217) immediately downstream from the OARE in the CYP2B6 promoter. Both DNA affinity and chromatin immunoprecipitation assays showed that OA treatment dissociates SMC1 from the CYP2B6 promoter, reciprocating the indirect binding of CAR to OARE. These results are consistent with the conclusion that SMC1 binding represses OARE activity and its dissociation allows the recruitment of CAR to the OARE, synergizing PBREM activity and the expression of the CYP2B6 gene.

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Zubiaur, Pablo, Paula Fernández-Campos, Marcos Navares-Gómez, Paula Soria-Chacartegui, Gonzalo Villapalos-García, Manuel Román, Gina Mejía-Abril, Dolores Ochoa, and Francisco Abad-Santos. "Variants in COMT, CYP3A5, CYP2B6, and ABCG2 Alter Quetiapine Pharmacokinetics." Pharmaceutics 13, no. 10 (September 28, 2021): 1573. http://dx.doi.org/10.3390/pharmaceutics13101573.

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Quetiapine is an atypical antipsychotic widely used for the treatment of schizophrenia and the depressive episodes of bipolar disorder. The aim of this work was to investigate the effect of variants in relevant pharmacogenes in the pharmacokinetics of quetiapine and to exploratorily evaluate adverse drug reaction (ADR) incidence based on genetic polymorphism. Specifically, 49 healthy volunteers enrolled in two bioequivalence clinical trials were included in this study. In addition, 80 variants in 19 relevant pharmacogenes were genotyped, including cytochrome P450 (CYP) genes, catechol-O-methyl transferase (COMT), other enzymes (e.g., UGT1A1 or UGT1A4), and transporters (e.g., SLCO1B1, ABCB1, or ABCG2). The COMT rs13306278 T allele was significantly related to quetiapine-increased exposure. We demonstrated the existence of quetiapine derivatives with a catechol-like structure (7,8-dihydroxi-quetiapine and 7,8-dihydroxi-N-desalkyl-quetiapine), which would be COMT metabolites and would explain quetiapine accumulation through CYP2D6 and CYP3A4 negative feedback. Moreover, CYP3A5 and CYP2B6 phenotypes were related to quetiapine exposure variability, which confirms (for CYP3A5) and suggests (for CYP2B6) that these enzymes play an important role in quetiapine’s metabolism. Finally, the ABCG2 rs2231142 T allele was related to quetiapine accumulation. Further studies are required to confirm the clinical relevance of our findings.

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Wang, Jishi, Yuan Yang, Wei Zhang, and Pengxiang Guo. "Targeted Anti-Tumor Research of Mesenchymal Stem Cells Delivered Enzyme-Prodrug Gene CYP450." Blood 114, no. 22 (November 20, 2009): 3582. http://dx.doi.org/10.1182/blood.v114.22.3582.3582.

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Abstract Abstract 3582 Poster Board III-519 Objective Cytochrome P450(CYP450-CYP1A2 /CYP2B6/CYP2C9) was transfected into human bone marrow-derived mesenchymal stem cells (hBMSCs), and the targed anti-tumor effect of BMSC-CYP450 cooperated with enzyme-prodrug(Dacarbazine (DTIC)/Cyclophosphamide (CPA)) was measured to provide laboratory data base for gene directed enzyme prodrug targeted anti-tumor therapy (GDEPT) which used BMSC as vehicles. Methods We respectively cloned CYP1A2/CYP2B6/CYP2C9 cDNA from human liver and constructed recombinant adenovirus vectors(pAd5CMV-NpA-CYP1A2/ pAd5CMV-NpA-CYP2B6/pAd5CMV-NpA-CYP2C9) which titer was 1×1012 pfu/mL. These hBMSCs were separated, cultured, purified, and detected by morphology, flow cytometry, osteogenic, adipogenic and chondrogenic induction, and RT-PCR(A surface marker for the identification of MSCs-the neural ganglioside GD2 gene). The tropism of BMSCs for cancer cells was detected by Transwell inserts technique. These recombinant vectors were transferred into BMSCs and A375/K562 cells, and the expression of EGFP and CYP1A2/CYP2B6/CYP2C9 was detected by fluorescence microscope, RT-PCR and Western blot respectively. Inverted microscope, MTT and Annexin V-FITC/PI detected the anti-tumor effect of CYP450 recombinant adenovirus vectors combined with chemotherapeutic prodrug DTIC/CPA in vitro. A human melanoma(A375) BALB/c nude mice model and a human myelocytic leukemia(K562) BALB/c nude mice model was constructed and detected by immuno-histochemistry analysis. The CYP1A2 gene tranfected BMSCs were injected into the A375 BALB/c nude mice model in combination with DTIC through caudal vein, while CYP2B6/CYP2C9 gene tranfected BMSCs were injected into K562 BALB/c nude mice model in combination with CPA in the same way. The measurement of tumors size, fluorescence microscope and TUNEL were used to detect anti-tumor effect of BMSCs-CYP1A2 cooperating with DTIC and BMSCs-CYP2B6/CYP2C9 with CPA in vivo. Results We constructed the recombinant adenovirus vectors pAd5CMV-NpA-CYP1A2/pAd5CMV-NpA-CYP2B6/pAd5CMV-NpA-CYP2C9 and pAd5CMV-NpA-EGFP successfully. BMSCs was separated successfully, and it respectively showed that BMSCs can migrate through the polycarbonate filter toward K562 and A375 cells in the lower chamber in vitro. Fluorescence microscope detected the expression of EGFP, while both RT-PCR and Western blot detected high expression of CYP1A2/CYP2B6/CYP2C9 in gene-transfected group cells. Inverted microscope, MTT and Annexin V-FITC/PI confirmed that BMSCs transferred with CYP1A2/CYP2B6/CYP2C9 recombinant adenovirus vectors could activate DTIC/CPA and increase its anti-tumor effect(In the DTIC/CPA concentration(0.05 mmol/L/2.5 mmol/L) which BMSCs was relatively safe, the cell apoptosis was (38.38±2.27)% (P<0.01), (42.69±2.03)% (P<0.01) and (39. 51±1.94)% (P<0.01) in BMSCs-CYP1A2+A375 group, BMSCs-CYP2B6+K562 group and BMSCs-CYP2C9+K562 group respectively. ). A375 and K562 BALB/c nude mice model was constructed successfully. The sizes of the tumor in the nude mice treated with transfected BMSCs and DTIC/CPA were significantly smaller than control case and changed along with concentration(P< 0.01, P< 0.05).BMSCs was congregated to tumor site in fluorescence microscope. Apoptosis of tumor cells was conspicuously more in BMSCs-CYP1A2+A375/BMSCs-CYP2B6+K562/BMSCs-CYP2C9+K562 treatment group than in control group by TUNEL. Conclusion BMSCs had the tropism for cancer cells in vitro and vivo. DTIC can be catalyzed by CYP2E1/CYP1A2, while CPA by CYP2B6/CYP2C9 in vitro and vivo. BMSC-based enzyme prodrug system of CYP2E1/CYP1A2 and DTIC can induce A375 cells apoptosis, while BMSC-based enzyme prodrug system of CYP2B6/CYP2C9 and CPA can induce K562 cells apoptosis in vitro and targetedly in vivo. Disclosures: No relevant conflicts of interest to declare.

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Chawar, Caroul, Alannah Hillmer, Amel Lamri, Flavio Kapczinski, Lehana Thabane, Guillaume Pare, and Zainab Samaan. "Implications of OPRM1 and CYP2B6 variants on treatment outcomes in methadone-maintained patients in Ontario: Exploring sex differences." PLOS ONE 16, no. 12 (December 15, 2021): e0261201. http://dx.doi.org/10.1371/journal.pone.0261201.

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Genetic variants in the OPRM1 and CYP2B6 genes, respectively coding for an opioid receptor and methadone metabolizers, have been linked to negative treatment outcomes in patients undergoing methadone maintenance treatment, with little consensus on their effect. This study aims to test the associations between pre-selected SNPs of OPRM1 and CYP2B6 and outcomes of continued opioid use, relapse, and methadone dose. It also aims to observe differences in associations within the sexes. 1,172 participants treated with methadone (nMale = 666, nFemale = 506) were included in this study. SNPs rs73568641 and rs7451325 from OPRM1 and all the tested CYP2B6 SNPs were detected to be in high linkage disequilibrium. Though no associations were found to be significant, noteworthy differences were observed in associations of OPRM1 rs73568641 and CYP2B6 rs3745274 with treatment outcomes between males and females. Further research is needed to determine if sex-specific differences are present.

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Usami, Osamu, Yugo Ashino, Yuichi Komaki, Masafumi Tomaki, Toshiya Irokawa, Tsutomu Tamada, Tsunefusa Hayashida, Katsuji Teruya, and Toshio Hattori. "Efavirenz-induced neurological symptoms in rare homozygote CYP2B6 *2/*2 (C64T)." International Journal of STD & AIDS 18, no. 8 (August 1, 2007): 575–76. http://dx.doi.org/10.1258/095646207781439810.

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Some of the HIV-1-infected patients who were given highly active anti-retroviral therapy (HAART) including efavirenz (EFV) presented adverse central nervous system (CNS) symptoms such as fatigue and insomnia. The incidence of adverse CNS symptoms is associated with hepatic cytochrome P450 isozymes (CYP2B6) polymorphisms. For example, CYP2B6 *6 (G516T and A785G) and *7 (G516T, A785G and C1459T) prolonged the EFV half-life despite discontinuation of EFV. CYP2B6 *2/*2 (C64T) is extremely rare and there have been no data describing the EFV plasma concentrations in C64T homozygous patients, who developed adverse CNS symptoms. C64T homozygous possibly has some catalytic defects.

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Heil, Sandra G., Marchina E. van der Ende, Paul W. Schenk, Ilse van der Heiden, Jan Lindemans, David Burger, and Ron H. N. van Schaik. "Associations Between ABCB1, CYP2A6, CYP2B6, CYP2D6, and CYP3A5 Alleles in Relation to Efavirenz and Nevirapine Pharmacokinetics in HIV-Infected Individuals." Therapeutic Drug Monitoring 34, no. 2 (April 2012): 153–59. http://dx.doi.org/10.1097/ftd.0b013e31824868f3.

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Uwimana, Eric, Patricia Ruiz, Xueshu Li, and Hans-Joachim Lehmler. "Human CYP2A6, CYP2B6, AND CYP2E1 Atropselectively Metabolize Polychlorinated Biphenyls to Hydroxylated Metabolites." Environmental Science & Technology 53, no. 4 (December 21, 2018): 2114–23. http://dx.doi.org/10.1021/acs.est.8b05250.

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Gravel, Sophie, Jean-Louis Chiasson, Suzanne Dallaire, Jacques Turgeon, and Veronique Michaud. "Evaluating the impact of type 2 diabetes mellitus on CYP450 metabolic activities: protocol for a case–control pharmacokinetic study." BMJ Open 8, no. 2 (February 2018): e020922. http://dx.doi.org/10.1136/bmjopen-2017-020922.

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IntroductionDiabetes affects more than 9% of the adult population worldwide. Patients with type 2 diabetes mellitus (T2DM) show variable responses to some drugs which may be due, in part, to variability in the functional activity of drug-metabolising enzymes including cytochromes P450 (CYP450s). CYP450 is a superfamily of enzymes responsible for xenobiotic metabolism. Knowledge must be gained on the impact of T2DM and related inflammatory processes on drug metabolism and its consequences on drug response. The aim of this study is to characterise the activity of CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP3A4/5 in T2DM versus non-T2DM subjects following the administration of a cocktail of probe drug substrates.Methods and analysisThis single-centre clinical study proposes the first detailed characterisation of T2DM impacts on major CYP450 drug-metabolising enzyme activities. We intend to recruit 42 patients with controlled T2DM (A1C≤7%), 42 patients with uncontrolled T2DM (A1C>7%) and 42 non-diabetic control subjects. The primary objective is to determine and compare major CYP450 activities in patients with T2DM versus non-diabetic subjects by dosing in plasma and urine probe drug substrates and metabolites following the oral administration of a drug cocktail: caffeine (CYP1A2), bupropion (CYP2B6), tolbutamide (CYP2C9), omeprazole (CYP2C19), dextromethorphan (CYP2D6), chlorzoxazone (CYP2E1) and midazolam (CYP3A4/5). Secondary objectives will evaluate the influence of variables such as glycaemia, insulinaemia, genetic polymorphisms and inflammation. The value of an endogenous biomarker of CYP3A activity is also evaluated. The first patient was recruited in May 2015 and patients will be enrolled up to completion of study groups.Ethics and disseminationApproval was obtained from the ethic review board of the CHUM research centre (Montreal, Canada).Trial registration numberNCT02291666.

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Ahmed, Sagheer, Hizbullah Khan, Asifullah Khan, Muhammad Hanif Bangash, Abrar Hussain, Mughal Qayum, and Mohammad Hamid Hamdard. "Inter-ethnic genetic variations and novel variant identification in the partial sequences of CYP2B6 gene in Pakistani population." PeerJ 9 (July 23, 2021): e11149. http://dx.doi.org/10.7717/peerj.11149.

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Background Some single nucleotide polymorphisms (SNPs) in the cytochrome P450 (CYP)2B6 gene lead to decreased enzyme activity and have an impact on drug metabolism. The present study was designed to investigate the patterns of genetic distinction across a hypervariable region of the CYP2B6 gene, known to contain important SNPs, i.e. rs4803419 and rs3745274, among five major ethnic groups of the Pakistani population. Methods Arlequin v3.5.DnaSPv6.12. and network 5 resources were used to analyze population genetic variance in the partial CYP2B6 gene sequences obtained from 104 human samples belonging to Punjabi, Pathan, Sindhi, Seraiki and Baloch ethnicities of Pakistan. The partial CYP2B6 gene region analyzed in the current study is previously known to possess important SNPs. Results The data analyses revealed that genetic variance among samples mainly came from differentiation within the ethnic groups. However, significant genetic variation was also found among the various ethnic groups. The high pairwise Fst genetic distinction was observed between Seraiki and Sindhi ethnic groups (Fst = 0.13392, P-value = 0.026) as well as between Seraiki and Balochi groups (Fst = 0.04303, P-value = −0.0030). However, the degree of genetic distinction was low between Pathan and Punjabi ethnic groups. Some SNPs, including rs3745274 and rs4803419, which are previously shown in strong association with increased plasma Efavirenz level, were found in high frequency. Besides, a novel SNP, which was not found in dbSNP and Ensemble databases, was identified in the Balochi ethnicity. This novel SNP is predicted to affect the CYP2B6 splicing pattern. Conclusion These results may have significant implications in Pakistani ethnicities in the context of drugs metabolized by CYP2B6, especially in Seraiki and Balochi ethnicity. The novel heterogeneous SNP, found in the present study, might lead to altered drug-metabolizing potential of CYP2B6 and, therefore, may be implicated in non-responder phenomenon.

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Journal articles on the topic 'CYP2B6'

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