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Desta Z, El-Boraie A, Gong L, Somogyi AA, Lauschke VM, Dandara C, Klein K, Miller NA, Klein TE, Tyndale RF, Whirl-Carrillo M, Gaedigk A. PharmVar GeneFocus: CYP2B6. Clin Pharmacol Ther 2021; 110:82-97. [PMID: 33448339 DOI: 10.1002/cpt.2166] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 12/21/2020] [Indexed: 12/12/2022]
Abstract
The Pharmacogene Variation Consortium (PharmVar) catalogs star (*) allele nomenclature for the polymorphic human CYP2B6 gene. Genetic variation within the CYP2B6 gene locus impacts the metabolism or bioactivation of clinically important drugs. Of particular importance are efficacy and safety concerns regarding: efavirenz, which is used for the treatment of HIV type-1 infection; methadone, a mainstay in the treatment of opioid use disorder and as an analgesic; ketamine, used as an antidepressant and analgesic; and bupropion, which is prescribed to treat depression and for smoking cessation. This GeneFocus provides a comprehensive overview and summary of CYP2B6 and describes how haplotype information catalogued by PharmVar is utilized by the Pharmacogenomics Knowledgebase (PharmGKB) and the Clinical Pharmacogenetics Implementation Consortium (CPIC).
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Affiliation(s)
- Zeruesenay Desta
- Division of Clinical Pharmacology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Ahmed El-Boraie
- Centre for Addiction and Mental Health and Departments of Pharmacology & Toxicology, and Psychiatry, University of Toronto, Toronto, Canada
| | - Li Gong
- Department of Biomedical Data Science, Stanford University, Stanford, California, USA
| | - Andrew A Somogyi
- Discipline of Pharmacology, Adelaide Medical School, University of Adelaide, Adelaide, Australia
| | - Volker M Lauschke
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Collet Dandara
- Division of Human Genetics, Department of Pathology & Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Kathrin Klein
- Dr. Margarete Fischer-Bosch-Institute of Clinical Pharmacology, Stuttgart, Germany.,University of Tuebingen, Tuebingen, Germany
| | - Neil A Miller
- Genomic Medicine Center, Children's Mercy, Kansas City, Missouri, USA.,School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - Teri E Klein
- Department of Biomedical Data Science, Stanford University, Stanford, California, USA
| | - Rachel F Tyndale
- Centre for Addiction and Mental Health and Departments of Pharmacology & Toxicology, and Psychiatry, University of Toronto, Toronto, Canada
| | | | - Andrea Gaedigk
- Division of Clinical Pharmacology, Toxicology & Therapeutic Innovation, Children's Mercy, Kansas City, Missouri, USA.,School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA
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Xu C, Luo M, Jiang H, Yu L, Zeng S. Involvement of CAR and PXR in the transcriptional regulation of CYP2B6 gene expression by ingredients from herbal medicines. Xenobiotica 2015; 45:773-81. [DOI: 10.3109/00498254.2015.1020076] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Nirogi R, Palacharla RC, Mohammed AR, Manoharan A, Ponnamaneni RK, Bhyrapuneni G. Evaluation of metabolism dependent inhibition of CYP2B6 mediated bupropion hydroxylation in human liver microsomes by monoamine oxidase inhibitors and prediction of potential as perpetrators of drug interaction. Chem Biol Interact 2015; 230:9-20. [DOI: 10.1016/j.cbi.2015.01.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Revised: 01/13/2015] [Accepted: 01/24/2015] [Indexed: 12/31/2022]
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Turpeinen M, Zanger UM. Cytochrome P450 2B6: function, genetics, and clinical relevance. ACTA ACUST UNITED AC 2013; 27:185-97. [PMID: 23152403 DOI: 10.1515/dmdi-2012-0027] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 10/15/2012] [Indexed: 12/17/2022]
Abstract
Cytochrome P450 (CYP) 2B6 belongs to the set of important hepatic drug-metabolizing CYPs. It makes up roughly 3%-6% of total hepatic CYP content and metabolizes several pharmaceuticals including bupropion, efavirenz, cyclophosphamide, pethidine, ketamine and propofol. The enzyme is susceptible to drug-drug interactions by enzyme induction and inhibition. In addition to drugs, CYP2B6 is able to both detoxify and bioactivate a number of procarcinogens and environmental agents including pesticides and herbicides. There is an extensive interindividual variability in the expression of CYP2B6, which is in part explained by extensive genetic polymorphism. CYP2B6 is one of the most polymorphic CYP genes in humans with over 100 described SNPs, numerous complex haplotypes and distinct ethnic and racial frequencies. This review summarizes the basic properties of CYP2B6 and the main characteristics of clinical relevance.
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Affiliation(s)
- Miia Turpeinen
- Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland.
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Zanger UM, Klein K. Pharmacogenetics of cytochrome P450 2B6 (CYP2B6): advances on polymorphisms, mechanisms, and clinical relevance. Front Genet 2013; 4:24. [PMID: 23467454 PMCID: PMC3588594 DOI: 10.3389/fgene.2013.00024] [Citation(s) in RCA: 206] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 02/14/2013] [Indexed: 12/22/2022] Open
Abstract
Cytochrome P450 2B6 (CYP2B6) belongs to the minor drug metabolizing P450s in human liver. Expression is highly variable both between individuals and within individuals, owing to non-genetic factors, genetic polymorphisms, inducibility, and irreversible inhibition by many compounds. Drugs metabolized mainly by CYP2B6 include artemisinin, bupropion, cyclophosphamide, efavirenz, ketamine, and methadone. CYP2B6 is one of the most polymorphic CYP genes in humans and variants have been shown to affect transcriptional regulation, splicing, mRNA and protein expression, and catalytic activity. Some variants appear to affect several functional levels simultaneously, thus, combined in haplotypes, leading to complex interactions between substrate-dependent and -independent mechanisms. The most common functionally deficient allele is CYP2B6*6 [Q172H, K262R], which occurs at frequencies of 15 to over 60% in different populations. The allele leads to lower expression in liver due to erroneous splicing. Recent investigations suggest that the amino acid changes contribute complex substrate-dependent effects at the activity level, although data from recombinant systems used by different researchers are not well in agreement with each other. Another important variant, CYP2B6*18 [I328T], occurs predominantly in Africans (4-12%) and does not express functional protein. A large number of uncharacterized variants are currently emerging from different ethnicities in the course of the 1000 Genomes Project. The CYP2B6 polymorphism is clinically relevant for HIV-infected patients treated with the reverse transcriptase inhibitor efavirenz, but it is increasingly being recognized for other drug substrates. This review summarizes recent advances on the functional and clinical significance of CYP2B6 and its genetic polymorphism, with particular emphasis on the comparison of kinetic data obtained with different substrates for variants expressed in different recombinant expression systems.
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Affiliation(s)
- Ulrich M Zanger
- Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology Stuttgart, Germany ; The University of Tuebingen Tuebingen, Germany
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Honda M, Muroi Y, Tamaki Y, Saigusa D, Suzuki N, Tomioka Y, Matsubara Y, Oda A, Hirasawa N, Hiratsuka M. Functional Characterization of CYP2B6 Allelic Variants in Demethylation of Antimalarial Artemether. Drug Metab Dispos 2011; 39:1860-5. [DOI: 10.1124/dmd.111.040352] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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Niu RJ, Zheng QC, Zhang JL, Zhang HX. Analysis of clinically relevant substrates of CYP2B6 enzyme by computational methods. J Mol Model 2011; 17:2839-46. [PMID: 21301907 DOI: 10.1007/s00894-011-0970-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Accepted: 01/11/2011] [Indexed: 12/12/2022]
Abstract
Mounting evidence thus far indicates that human cytochrome P450 2B6 (CYP2B6), an enzyme expressed at a relatively low level functionally, is primarily responsible for the metabolism of several clinically relevant drugs, including propofol, efavirenz, bupropion, mephobarbital, and the propofol analog 2,6-di-sec-butyl phenol. We used molecular dynamics and molecular docking methods to predict such interactions and to compare with experimentally measured metabolisms. Insight II and Discover Studio 2.5 were used to carry out the docking of these substrates into CYP2B6 to explore the critical residues and interaction energies of the complexes. Phe297, Glu301, Thr302 and Val367 were identified as major drug-binding residues, which is consistent with previous data on site-directed mutagenesis, crystallography structure, and from modeling and docking studies. In addition, our docking results suggest that nonpolar amino acid clusters and heme also participate in binding to mediate drug oxidative metabolism. The binding modes of the five clinically relevant substrates mentioned above for metabolism on CYP2B6 are presented.
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Affiliation(s)
- Rui-Juan Niu
- State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China
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Srinivas NR. Baicalin, an emerging multi-therapeutic agent: pharmacodynamics, pharmacokinetics, and considerations from drug development perspectives. Xenobiotica 2010; 40:357-67. [PMID: 20230189 DOI: 10.3109/00498251003663724] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Baicalin was extensively researched for utility in a number of therapeutic areas owing to its anti-inflammatory, anti-oxidant, anti-bacterial, and anti-cancer properties. A number of preclinical studies, in vitro work, and mechanistic studies were performed to understand the absorption, distribution, metabolism, and excretion profiles of baicalin. The absorption of baicalin involved several complexities: the restriction to two distant sites; the conversion of baicalin to baicalein; the possible role of transporter(s); and enhanced absorption due to breakdown of conjugates by beta-glucuronidase. Limited distribution data suggest that baicalin reached several sites such as the brain, eye lens, thymus, etc. Hepatobiliary recycling also served as a distribution phase for sustained delivery of baicalin. Metabolism data suggest the rapid conversion of baicalin to baicalein, which was extensively subjected to Phase 2 metabolism, conjugates baicalein glucuronide/sulfate have been identified. Limited excretion data suggest involvement of renal and faecal routes--glucuronide and sulfate conjugates were excreted in urine and faeces (via biliary excretion). The published data on baicalin suggest imminent challenges for developing baicalin and/or during co-administration with other agents. These challenges are absorption related (transporter or changes in the microenvironment), metabolism related (CYP2B6 induction and/or CYP2E1 inhibition), and excretion/efflux related (competitive biliary pathway and/or OATP1B1 transport).
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