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Langlois AWR, Chenoweth MJ, Twesigomwe D, Scantamburlo G, Whirl-Carrillo M, Sangkuhl K, Klein TE, Nofziger C, Tyndale RF, Gaedigk A. PharmVar GeneFocus: CYP2A6. Clin Pharmacol Ther 2024; 116:948-962. [PMID: 39051767 DOI: 10.1002/cpt.3387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Accepted: 07/08/2024] [Indexed: 07/27/2024]
Abstract
The Pharmacogene Variation Consortium (PharmVar) provides nomenclature for the human CYP2A gene locus containing the highly polymorphic CYP2A6 gene. CYP2A6 plays a role in the metabolism of nicotine and various drugs. Thus, genetic variation can substantially contribute to the function of this enzyme and associated efficacy and safety. This GeneFocus provides an overview of the clinical significance of CYP2A6, including its genetic variation and function. We also highlight and discuss caveats in the identification and characterization of allelic variation of this complex pharmacogene, a prerequisite for accurate genotype determination and prediction of phenotype status.
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Affiliation(s)
- Alec W R Langlois
- Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Meghan J Chenoweth
- Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - David Twesigomwe
- Sydney Brenner Institute for Molecular Bioscience, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | | | | | - Katrin Sangkuhl
- Department of Biomedical Data Science, Stanford University, Stanford, California, USA
| | - Teri E Klein
- Department of Biomedical Data Science, Stanford University, Stanford, California, USA
- Departments of Medicine (BMIR) and Genetics, Stanford University, Stanford, California, USA
| | | | - Rachel F Tyndale
- Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Andrea Gaedigk
- Division of Clinical Pharmacology, Toxicology and Therapeutic Innovation, Children's Mercy Research Institute (CMRI), Kansas City, Missouri, USA
- School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA
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Perez-Paramo YX, Watson CJ, Chen G, Thomas CE, Adams-Haduch J, Wang R, Khor CC, Koh WP, Nelson HH, Yuan JM, Lazarus P. Impact of Genetic Variants in the Nicotine Metabolism Pathway on Nicotine Metabolite Levels in Smokers. Cancer Epidemiol Biomarkers Prev 2023; 32:54-65. [PMID: 36252563 PMCID: PMC9827107 DOI: 10.1158/1055-9965.epi-22-0868] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 09/14/2022] [Accepted: 10/11/2022] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Nicotine metabolism is a major factor in nicotine dependence, with approximately 70% to 80% of nicotine metabolized to cotinine in Caucasians. Cotinine formation is catalyzed primarily by CYP2A6, which also converts cotinine to trans-3'-hydroxycotinine (3HC). The goal of the present study was to examine the effects of CYP2A6 deficiency on nicotine metabolism profiles in vivo and the importance of genetic variants in nicotine-metabolizing enzyme genes on urinary nicotine metabolites levels. METHODS Urine samples from 722 smokers who participated in the Singapore Chinese Health Study were analyzed using UPLC-MS/MS to detect nicotine and eight of its urinary metabolites, and a total of 58 variants in 12 genes involved in nicotine metabolism were investigated in 475 of these subjects with informative genotyping data. RESULTS Urine samples stratified by the ratio of 3HC/cotinine exhibited a 7-fold increase in nicotine-N'-oxide, a 6-fold increase in nicotine-Glucuronide (Gluc), and a 5-fold decrease in 3HC-Gluc when comparing the lower versus upper 3HC/cotinine ventiles. Significant (P < 0.0001) associations were observed between functional metabolizing enzyme genotypes and levels of various urinary nicotine metabolites, including CYP2A6 genotype and levels of nicotine, nicotine-Gluc, nicotine-N'-oxide and 3HC, UGT2B10 genotype and levels of cotinine, nicotine-Gluc and cotinine-Gluc, UGT2B17 genotype and levels of 3HC-Gluc, FMO3 genotype and levels of nicotine-N'-oxide, and CYP2B6 genotype and levels of nicotine-N'-oxide and 4-hydroxy-4-(3-pyridyl)-butanoic acid. CONCLUSIONS These data suggest that several pathways are important in nicotine metabolism. IMPACT Genotype differences in several nicotine-metabolizing enzyme pathways may potentially lead to differences in nicotine dependence and smoking behavior and cessation.
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Affiliation(s)
- Yadira X. Perez-Paramo
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Christy J.W. Watson
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Gang Chen
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Claire E. Thomas
- Division of Cancer Control and Population Sciences, UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Jennifer Adams-Haduch
- Division of Cancer Control and Population Sciences, UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Renwei Wang
- Division of Cancer Control and Population Sciences, UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Chiea Chuen Khor
- Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, Singapore.,Singapore Eye Research Institute, Singapore, Singapore.,Eye Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore
| | - Woon-Puay Koh
- Health Services and Systems Research, Duke-NUS Medical School Singapore, Singapore, Singapore.,Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore
| | - Heather H. Nelson
- Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota.,Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, Minnesota
| | - Jian-Min Yuan
- Division of Cancer Control and Population Sciences, UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania.,Corresponding Authors: Philip Lazarus, College of Pharmacy and Pharmaceutical Sciences, Washington State University, PBS building, Room 431, Spokane, Washington, 99210-1495. E-mail: ; and Jian-Min Yuan, Division of Cancer Control and Population Sciences, UPMC Hillman Cancer Center, University of Pittsburgh, 5150 Centre Avenue, Pittsburgh, Pennsylvania, 15232. E-mail:
| | - Philip Lazarus
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington.,Corresponding Authors: Philip Lazarus, College of Pharmacy and Pharmaceutical Sciences, Washington State University, PBS building, Room 431, Spokane, Washington, 99210-1495. E-mail: ; and Jian-Min Yuan, Division of Cancer Control and Population Sciences, UPMC Hillman Cancer Center, University of Pittsburgh, 5150 Centre Avenue, Pittsburgh, Pennsylvania, 15232. E-mail:
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Perez-Paramo YX, Watson CJW, Chen G, Lazarus P. CYP2C19 Plays a Major Role in the Hepatic N-Oxidation of Cotinine. Drug Metab Dispos 2023; 51:29-37. [PMID: 35197312 PMCID: PMC9832378 DOI: 10.1124/dmd.121.000624] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 02/08/2022] [Accepted: 02/14/2022] [Indexed: 01/14/2023] Open
Abstract
The primary mode of metabolism of nicotine is via the formation of cotinine by the enzyme CYP2A6. Cotinine undergoes further CYP2A6-mediated metabolism by hydroxylation to 3-hydroxycotinine and norcotinine, but can also form cotinine-N-glucuronide and cotinine-N-oxide (COX). The goal of this study was to investigate the enzymes that catalyze COX formation and determine whether genetic variation in these enzymes may affect this pathway. Specific inhibitors of major hepatic cytochrome P450 (P450) enzymes were used in cotinine-N-oxidation reactions using pooled human liver microsomes (HLMs). COX formation was monitored by ultrahigh-pressure liquid chromatography-tandem mass spectrometry and enzyme kinetic analysis was performed using microsomes from P450-overexpressing human embryonic kidney 293 (HEK293) cell lines. Genotype-phenotype analysis was performed in a panel of 113 human liver specimens. Inhibition of COX formation was only observed in HLMs when using inhibitors of CYP2A6, CYP2B6, CYP2C19, CYP2E1, and CYP3A4. Microsomes from cells overexpressing CYP2A6 or CYP2C19 exhibited similar N-oxidation activity against cotinine, with maximum reaction rate over Michaelis constant values (intrinsic clearance) of 4.4 and 4.2 nL/min/mg, respectively. CYP2B6-, CYP2E1-, and CYP3A4-overexpressing microsomes were also active in COX formation. Significant associations (P < 0.05) were observed between COX formation and genetic variants in CYP2C19 (*2 and *17 alleles) in HLMs. These results demonstrate that genetic variants in CYP2C19 are associated with decreased COX formation, potentially affecting the relative levels of cotinine in the plasma or urine of smokers and ultimately affecting recommended smoking cessation therapies. SIGNIFICANCE STATEMENT: This study is the first to elucidate the enzymes responsible for cotinine-N-oxide formation and genetic variants that affect this biological pathway. Genetic variants in CYP2C19 have the potential to modify nicotine metabolic ratio in smokers and could affect pharmacotherapeutic decisions for smoking cessation treatments.
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Affiliation(s)
- Yadira X Perez-Paramo
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Christy J W Watson
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Gang Chen
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Philip Lazarus
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington
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Guo Y, Li S, Wang Z, Jiang F, Guan Y, Huang M, Zhong G. Nicotine Delivery and Pharmacokinetics of an Electronic Cigarette Compared With Conventional Cigarettes in Chinese Adult Smokers: A Randomized Open-Label Crossover Clinical Study. NICOTINE & TOBACCO RESEARCH : OFFICIAL JOURNAL OF THE SOCIETY FOR RESEARCH ON NICOTINE AND TOBACCO 2022; 24:1881-1888. [PMID: 35690060 DOI: 10.1093/ntr/ntac143] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 05/10/2022] [Accepted: 06/10/2022] [Indexed: 01/03/2023]
Abstract
INTRODUCTION To evaluate the nicotine pharmacokinetics of a commercial electronic cigarette (e-cigarette) relative to conventional cigarettes in Chinese adult smokers. AIMS AND METHODS A randomized, open-label, crossover clinical study was conducted on 23 healthy adult Chinese smokers. In two sessions, subjects used either the e-cigarettes with 30 mg/g nicotine in e-liquid or conventional cigarettes of a given brand, at one puff every 30 seconds for a total of 10 puffs. Blood samples were collected at specified time points for 4 hours after the first puff. Subjective effects on desire-to-smoke and physiological parameters such as heart rate and oxyhemoglobin saturation levels were also examined before and after using the two products. RESULTS The baseline-adjusted maximum nicotine concentration (Cmax-BL), time-to-peak nicotine concentration (Tmax), and nicotine absorption rate (Cmax-BL divided by Tmax) were found to be similar for the e-cigarette versus those of conventional cigarettes (p > .05). Total nicotine exposure measured as the area-under-curve (AUC0-t-BL) was significantly lower for the e-cigarette relative to that of conventional cigarettes. In addition, the subjects found that e-cigarettes were well tolerated under controlled puffing conditions. CONCLUSIONS The test e-cigarettes achieved similar nicotine delivery and pharmacokinetic profiles to those of the comparator cigarettes, indicating that this e-cigarette could be a potential alternative to conventional cigarettes for those adult smokers. IMPLICATIONS There are no data in the published literature on the nicotine pharmacokinetics of e-cigarettes in Chinese smokers. To the best of our knowledge, this is the first study to evaluate the nicotine delivery and pharmacokinetic profile of a commercial e-cigarette brand compared with conventional cigarettes in Chinese adult smokers. After the use of test e-cigarettes, nicotine delivery and pharmacokinetic profile were similar to those of conventional cigarettes in Chinese adult smokers.
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Affiliation(s)
- Yi Guo
- Institute of Clinical Pharmacology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Shoufeng Li
- Institute of Clinical Pharmacology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Zhi Wang
- Institute of Clinical Pharmacology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China.,Clinical Trial Center of Dongguan KangHua Hospital, Dongguan, Guangdong, China
| | - Fulin Jiang
- Institute of Clinical Pharmacology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Yanping Guan
- Institute of Clinical Pharmacology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Min Huang
- Institute of Clinical Pharmacology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Guoping Zhong
- Institute of Clinical Pharmacology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China.,Clinical Trial Center of Dongguan KangHua Hospital, Dongguan, Guangdong, China
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ClinPharmSeq: A targeted sequencing panel for clinical pharmacogenetics implementation. PLoS One 2022; 17:e0272129. [PMID: 35901010 PMCID: PMC9333201 DOI: 10.1371/journal.pone.0272129] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 07/12/2022] [Indexed: 12/02/2022] Open
Abstract
The accurate identification of genetic variants contributing to therapeutic drug response or adverse effects is the first step in implementation of precision drug therapy. Targeted sequencing has recently become a common methodology for large-scale studies of genetic variation thanks to its favorable balance between low cost, high throughput, and deep coverage. Here, we present ClinPharmSeq, a targeted sequencing panel of 59 genes with associations to pharmacogenetic (PGx) phenotypes, as a platform to explore the relationship between drug response and genetic variation, both common and rare. For validation, we sequenced DNA from 64 ethnically diverse Coriell samples with ClinPharmSeq to call star alleles (haplotype patterns) in 27 genes using the bioinformatics tool PyPGx. These reference samples were extensively characterized by multiple laboratories using PGx testing assays and, more recently, whole genome sequencing. We found that ClinPharmSeq can consistently generate deep-coverage data (mean = 274x) with high uniformity (30x or above = 94.8%). Our genotype analysis identified a total of 185 unique star alleles from sequencing data, and showed that diplotype calls from ClinPharmSeq are highly concordant with that from previous publications (97.6%) and whole genome sequencing (97.9%). Notably, all 19 star alleles with complex structural variation including gene deletions, duplications, and hybrids were recalled with 100% accuracy. Altogether, these results demonstrate that the ClinPharmSeq platform offers a feasible path for broad implementation of PGx testing and optimization of individual drug treatments.
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van Rensburg R, Nightingale S, Brey N, Albertyn CH, Kellermann TA, Taljaard JJ, Esterhuizen TM, Sinxadi PZ, Decloedt EH. Pharmacogenetics of the Late-Onset Efavirenz Neurotoxicity Syndrome (LENS). Clin Infect Dis 2021; 75:399-405. [PMID: 34882770 DOI: 10.1093/cid/ciab961] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND The late-onset efavirenz neurotoxicity syndrome (LENS) presents as ataxia and/or encephalopathy with supratherapeutic efavirenz plasma concentrations (>4 µg/mL). Efavirenz is primarily metabolized by cytochrome P450 2B6 (CYP2B6), with CYP2A6 as an accessory pathway. We hypothesized that participants with LENS would predominantly be CYP2B6 slow metabolizers. The aim of our study was to determine the frequency of CYP2B6 slow metabolizers in participants with LENS. METHODS Adult HIV-positive participants on efavirenz-based antiretroviral therapy presenting with LENS were prospectively enrolled. Genetic polymorphisms known to be associated with increased efavirenz plasma concentrations in CYP2B6 (rs3745274, rs28399499, rs4803419) and CYP2A6 (rs28399433) were selected and used to determine proportions of slow metabolizers. Pharmacokinetic analyses were performed using liquid chromatography-tandem mass spectrometry. Median (IQR) plasma efavirenz and 8-hydroxyefavirenz were described. RESULTS Fifteen participants were enrolled. Thirteen (13/15) were Black-African and 13 were female. Median weight was 49.9kg with a median duration on efavirenz of 2.2 years. All 15 participants were successfully genotyped as slow CYP2B6 metabolizers, with 6 participants additionally having CYP2A6 heterozygous genotype. Thirteen were receiving the CYP2A6 enzyme inhibitor isoniazid, and all 15 were genotypic NAT2 slow or intermediate acetylators. Efavirenz plasma concentration was markedly increased at 50.5 (47.0-65.4) µg/mL; 8-hydroxyefavirenz concentration was markedly decreased at 0.10 (0.07-0.15) µg/mL. CONCLUSIONS Our cohort provides definitive evidence that LENS is associated with the CYP2B6 slow metabolizer genotype, with a median efavirenz plasma concentration >12-fold higher than the defined upper limit of the therapeutic range. Isoniazid and low body weight are important contributors to LENS development.
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Affiliation(s)
- Roland van Rensburg
- Division of Clinical Pharmacology, Department of Medicine, Stellenbosch University, Cape Town, South Africa
| | - Sam Nightingale
- HIV Mental Health Research Unit, Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa
| | - Naeem Brey
- Division of Neurology, Department of Medicine, Stellenbosch University, Cape Town, South Africa
| | - Christine H Albertyn
- Division of Neurology, Department of Medicine, Stellenbosch University, Cape Town, South Africa
| | - Tracy A Kellermann
- Division of Clinical Pharmacology, Department of Medicine, Stellenbosch University, Cape Town, South Africa
| | - Jantjie J Taljaard
- Division of Infectious Diseases, Department of Medicine, Stellenbosch University, Cape Town, South Africa
| | - Tonya M Esterhuizen
- Division of Epidemiology and Biostatistics, Department of Global Health, Stellenbosch University, Cape Town, South Africaand
| | - Phumla Z Sinxadi
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Eric H Decloedt
- Division of Clinical Pharmacology, Department of Medicine, Stellenbosch University, Cape Town, South Africa
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Perez-Paramo YX, Lazarus P. Pharmacogenetics factors influencing smoking cessation success; the importance of nicotine metabolism. Expert Opin Drug Metab Toxicol 2021; 17:333-349. [PMID: 33322962 PMCID: PMC8049967 DOI: 10.1080/17425255.2021.1863948] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 12/10/2020] [Indexed: 01/12/2023]
Abstract
Introduction: Smoking remains a worldwide epidemic, and despite an increase in public acceptance of the harms of tobacco use, it remains the leading cause of preventable death. It is estimated that up to 70% of all smokers express a desire to quit, but only 3-5% of them are successful.Areas covered: The goal of this review was to evaluate the current status of smoking cessation treatments and the feasibility of implementing personalized-medicine approaches to these pharmacotherapies. We evaluated the genetics associated with higher levels of nicotine addiction and follow with an analysis of the genetic variants that affect the nicotine metabolic ratio (NMR) and the FDA approved treatments for smoking cessation. We also highlighted the gaps in the process of translating current laboratory understanding into clinical practice, and the benefits of personalized treatment approaches for a successful smoking cessation strategy.Expert opinion: Evidence supports the use of tailored therapies to ensure that the most efficient treatments are utilized in an individual's smoking cessation efforts. An understanding of the genetic effects on the efficacy of individualized smoking cessation pharmacotherapies is key to smoking cessation, ideally utilizing a polygenetic risk score that considers all genetic variation.
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Affiliation(s)
- Yadira X. Perez-Paramo
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington, USA
| | - Philip Lazarus
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington, USA
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Cheng Y, Dai R, Chen W, Li Q, Zhang C, Yang T. Genetic polymorphisms of pharmacogenomic VIP variants in the Dai population from Yunnan province. Mol Genet Genomic Med 2020; 8:e1231. [PMID: 32347657 PMCID: PMC7336744 DOI: 10.1002/mgg3.1231] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 02/04/2020] [Accepted: 02/24/2020] [Indexed: 12/17/2022] Open
Abstract
Background Pharmacogenomics plays a crucial role in individualized therapy, but the variant information of pharmacogenomics in the Dai population is limited. We therefore aimed to screen very important pharmacogenetic (VIP) in the Dai population and compared differences between Dai and other 25 populations. Methods In this study, we genotyped 73 VIP variants from the PharmGKB and compared genotype distribution of variants in Dai with other 25 populations by χ2 test. To assess the genetic relationship among 26 populations, we performed the structure analysis. In addition, pair‐wise F‐statistics (Fst) was calculated to measure the population differentiation. Results We found 12, 10, 13, 17, 11, 39, 46, 46, 45, 43, 49, 46, 46, 46, 49, 45, 41, 42, 48, 53, 45, 50, 50, 51, 47, and 50 significantly different variants in Dai compared with other 25 populations. Genetic structure analysis showed Dai had close relationships with CDX (Chinese Dai in Xishuangbanna), CHB (Han Chinese in Beijing), JPT (Japanese in Tokyo), and KHV (Kinh in Ho Chi Minh City, Vietnam). Moreover, Dai is the most similar to KHV according to Fst analysis. Conclusions Our study complement the pharmacogenomics information of Dai population from Yunnan province and provide a theoretical basis for personalized medicine.
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Affiliation(s)
- Yujing Cheng
- Department of Blood TransfusionThe First People’s Hospital of Yunnan ProvinceYunnan ProvinceKunmingChina
| | - Run Dai
- Department of Blood TransfusionThe First People’s Hospital of Yunnan ProvinceYunnan ProvinceKunmingChina
| | - Wanlu Chen
- Department of Blood TransfusionThe First People’s Hospital of Yunnan ProvinceYunnan ProvinceKunmingChina
| | - Qi Li
- Department of Blood TransfusionThe First People’s Hospital of Yunnan ProvinceYunnan ProvinceKunmingChina
| | - Chan Zhang
- Department of Blood TransfusionThe First People’s Hospital of Yunnan ProvinceYunnan ProvinceKunmingChina
| | - Tonghua Yang
- Department of HematologyThe First People’s Hospital of Yunnan ProvinceYunnan ProvinceKunmingChina
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Farra C, Assaf N, Karaky N, Diab S, Zaatari G, Cortas N, Daher RT. Association between CYP2A6 genotypes and smoking behavior in Lebanese smokers. Meta Gene 2020. [DOI: 10.1016/j.mgene.2019.100616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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10
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Influence of CYP2B6 activity score on the pharmacokinetics and safety of single dose efavirenz in healthy volunteers. THE PHARMACOGENOMICS JOURNAL 2019; 20:235-245. [PMID: 31628422 DOI: 10.1038/s41397-019-0103-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 09/10/2019] [Accepted: 10/02/2019] [Indexed: 01/11/2023]
Abstract
Efavirenz is a non-nucleoside reverse transcriptase inhibitor used as first-line therapy for the treatment of HIV infection. Cytochrome P450 (CYP) CYP2B6 G516T (rs3745274) is a well-known predictor of efavirenz disposition. Dose adjustment based on G516T variant has been shown to be beneficial. However, this variant cannot explain the entire variability of efavirenz pharmacokinetics. In this study, we evaluated the influence of 11 single-nucleotide polymorphisms (SNPs) in CYP2B6, CYP2A6, CYP3A and ABCB1 (ATP-binding cassette sub-family B member 1) on the pharmacokinetics and safety of efavirenz after single oral dose administration to 47 healthy volunteers. We designed and validated a CYP2B6 activity score model based on two CYP2B6 SNPs (G516T and rs4803419) that predicted efavirenz disposition better than G516T alone.
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11
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Hammad HM, Imraish A, Azab B, Best AM, Khader YS, Zihlif M. Associations of CYP2A6 Gene Polymorphism with Smoking Status Among Jordanians: Gender-Related Differences. Curr Drug Metab 2019; 20:765-770. [PMID: 31453782 DOI: 10.2174/1389200220666190827161112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 08/14/2019] [Accepted: 08/16/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND Cytochrome P450 2A6 enzyme (CYP2A6), an essential hepatic enzyme involved in the metabolism of drugs, is responsible for a major metabolic pathway of nicotine. Variation in the activity of polymorphic CYP2A6 alleles has been implicated in inter-individual differences in nicotine metabolism. AIMS The objective of the current study was to assess the association between the smoking status and the cytochrome P450 2A6 enzyme (CYP2A6) genotype in Jordanians. METHODS In the current study, 218 (117 Male and 101 female) healthy unrelated Jordanian volunteers were recruited. CYP2A6*1B, CYP2A6*4 and CYP2A6*9 were determined and correlated with subject smoking status. RESULTS *1A/*1A was the most common genetic polymorphism in the overall study population, with no significant frequency differences between smokers and non-smokers. When the population was divided according to gender, only male smokers showed a significant correlation between genotype and smoking status. Considering the CYP2A6*9 genotype, the results showed differences in distribution between smokers and non-smokers, but only women showed a significant association between CYP2A6*9 allele genotype and smoking status. CONCLUSION The results of this study show that there is a significant association between CYP2A6*9 genotype and smoking status. They also show that CYP2A6 genotype is significantly influenced by gender.
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Affiliation(s)
- Hana M Hammad
- Department of Biological Sciences, School of Science, The University of Jordan, Amman, Jordan
| | - Amer Imraish
- Department of Biological Sciences, School of Science, The University of Jordan, Amman, Jordan
| | - Belal Azab
- Department of Pathology, School of Medicine, The University of Jordan, Amman, Jordan
| | - Al M Best
- Virginia Commonwealth University, Richmond VA, United States
| | - Yousef S Khader
- Department of Community Medicine, Public Health and Family Medicine, Faculty of Medicine, Jordan University of Science & Technology, Irbid, Jordan
| | - Malek Zihlif
- Department of Pharmacology, School of Medicine, The University of Jordan, Amman, Jordan
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Borrie AE, Rose RV, Choi YH, Perera FE, Read N, Sexton T, Lock M, Vandenberg TA, Hahn K, Dinniwell R, Younus J, Logan D, Potvin K, Yaremko B, Yu E, Lenehan J, Welch S, Tyndale RF, Teft WA, Kim RB. Letrozole concentration is associated with CYP2A6 variation but not with arthralgia in patients with breast cancer. Breast Cancer Res Treat 2018; 172:371-379. [PMID: 30094551 DOI: 10.1007/s10549-018-4910-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Accepted: 08/02/2018] [Indexed: 12/28/2022]
Abstract
PURPOSE The aromatase inhibitor (AI) letrozole is a first-line drug in the adjuvant treatment of breast cancer in postmenopausal women. Adherence to AI therapy, including letrozole, remains problematic due to the development of debilitating AI-induced arthralgia. Letrozole is metabolized in the liver by CYP2A6. It remains unknown if plasma letrozole levels or CYP2A6 genetic variation is associated with the development of arthralgia. METHODS We enrolled 126 female breast cancer patients initiated on letrozole therapy and prospectively collected blood samples at baseline and two follow-up time points to determine letrozole plasma concentrations and CYP2A6 genotype. At each visit, participants completed two validated questionnaires to assess the severity of arthralgia symptoms. RESULTS More than half (55%) of patients experienced a significant increase in their arthralgia symptoms after initiation of treatment. The clinical variables of body mass index (P = 0.0003) and age (P = 0.0430) were negatively and positively associated with plasma letrozole concentrations, respectively. CYP2A6 genotype was significantly associated with letrozole levels (P < 0.0001), and increased plasma letrozole levels were observed in patients with CYP2A6 reduced-function genotypes. Plasma levels of letrozole and CYP2A6 genotype were not significantly associated with a change in pain score from baseline. CONCLUSIONS CYP2A6 genotype was a significant predictor of letrozole plasma levels, but was not associated with the development of arthralgia.
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Affiliation(s)
- Adrienne E Borrie
- Division of Clinical Pharmacology, Department of Medicine, Western University, London, ON, Canada.,Department of Physiology and Pharmacology, Western University, London, ON, Canada
| | - Rhiannon V Rose
- Department of Epidemiology and Biostatistics, Western University, London, ON, Canada
| | - Yun-Hee Choi
- Department of Epidemiology and Biostatistics, Western University, London, ON, Canada
| | | | - Nancy Read
- Department of Oncology, Western University, London, ON, Canada
| | - Tracy Sexton
- Department of Oncology, Western University, London, ON, Canada
| | - Michael Lock
- Department of Oncology, Western University, London, ON, Canada
| | | | - Karin Hahn
- Department of Oncology, Western University, London, ON, Canada
| | | | - Jawaid Younus
- Department of Oncology, Western University, London, ON, Canada
| | - Diane Logan
- Department of Oncology, Western University, London, ON, Canada
| | - Kylea Potvin
- Department of Oncology, Western University, London, ON, Canada
| | - Brian Yaremko
- Department of Oncology, Western University, London, ON, Canada
| | - Edward Yu
- Department of Oncology, Western University, London, ON, Canada
| | - John Lenehan
- Department of Oncology, Western University, London, ON, Canada
| | - Stephen Welch
- Department of Oncology, Western University, London, ON, Canada
| | - Rachel F Tyndale
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), University of Toronto, Toronto, ON, Canada.,Department of Psychiatry, and Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Wendy A Teft
- Division of Clinical Pharmacology, Department of Medicine, Western University, London, ON, Canada.,Department of Physiology and Pharmacology, Western University, London, ON, Canada
| | - Richard B Kim
- Division of Clinical Pharmacology, Department of Medicine, Western University, London, ON, Canada. .,Department of Physiology and Pharmacology, Western University, London, ON, Canada. .,LHSC - University Hospital, Western University, Room B9-116, 339 Windermere Road, London, ON, N6A 5A5, Canada.
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Dalwadi DA, Ozuna L, Harvey BH, Viljoen M, Schetz JA. Adverse Neuropsychiatric Events and Recreational Use of Efavirenz and Other HIV-1 Antiretroviral Drugs. Pharmacol Rev 2018; 70:684-711. [DOI: 10.1124/pr.117.013706] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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14
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Ezzeldin N, El-Lebedy D, Darwish A, El Bastawisy A, Abd Elaziz SH, Hassan MM, Saad-Hussein A. Association of genetic polymorphisms CYP2A6*2 rs1801272 and CYP2A6*9 rs28399433 with tobacco-induced lung Cancer: case-control study in an Egyptian population. BMC Cancer 2018; 18:525. [PMID: 29724170 PMCID: PMC5934827 DOI: 10.1186/s12885-018-4342-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 04/08/2018] [Indexed: 11/10/2022] Open
Abstract
Background Several studies have reported the role of CYP2A6 genetic polymorphisms in smoking and lung cancer risk with some contradictory results in different populations. The purpose of the current study is to assess the contribution of the CYP2A6*2 rs1801272 and CYP2A6*9 rs28399433 gene polymorphisms and tobacco smoking in the risk of lung cancer in an Egyptian population. Methods A case-control study was conducted on 150 lung cancer cases and 150 controls. All subjects were subjected to blood sampling for Extraction of genomic DNA and Genotyping of the CYP2A6 gene SNPs (CYP2A6*2 (1799 T > A) rs1801272 and CYP2A6*9 (− 48 T > G) rs28399433 by Real time PCR. Results AC and CC genotypes were detected in CYP2A6*9; and AT genotype in CYP2A6*2. The frequency of CYP2A6*2 and CYP2A6*9 were 0.7% and 3.7% respectively in the studied Egyptian population. All cancer cases with slow metabolizer variants were NSCLC. Non-smokers represented 71.4% of the CYP2A6 variants. There was no statistical significant association between risk of lung cancer, smoking habits, heaviness of smoking and the different polymorphisms of CYP2A6 genotypes. Conclusion The frequency of slow metabolizers CYP2A6*2 and CYP2A6*9 are poor in the studied Egyptian population. Our findings did not suggest any association between CYP2A6 genotypes and risk of lung cancer.
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Affiliation(s)
- Nada Ezzeldin
- Chest Diseases, National Research Center, Cairo, Egypt
| | | | - Amira Darwish
- Medical Oncology, National Cancer Institute, Cairo University, Cairo, Egypt. .,National Cancer Institute (NCI), Fom-Elkhalig Square, P.O.Box: 11796, Cairo, Egypt.
| | - Ahmed El Bastawisy
- Medical Oncology, National Cancer Institute, Cairo University, Cairo, Egypt
| | | | | | - Amal Saad-Hussein
- Environmental Health & Preventive Medicine, National Research Center, Cairo, Egypt
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15
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Chadaeva IV, Ponomarenko PM, Rasskazov DA, Sharypova EB, Kashina EV, Zhechev DA, Drachkova IA, Arkova OV, Savinkova LK, Ponomarenko MP, Kolchanov NA, Osadchuk LV, Osadchuk AV. Candidate SNP markers of reproductive potential are predicted by a significant change in the affinity of TATA-binding protein for human gene promoters. BMC Genomics 2018; 19:0. [PMID: 29504899 PMCID: PMC5836831 DOI: 10.1186/s12864-018-4478-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The progress of medicine, science, technology, education, and culture improves, year by year, quality of life and life expectancy of the populace. The modern human has a chance to further improve the quality and duration of his/her life and the lives of his/her loved ones by bringing their lifestyle in line with their sequenced individual genomes. With this in mind, one of genome-based developments at the junction of personalized medicine and bioinformatics will be considered in this work, where we used two Web services: (i) SNP_TATA_Comparator to search for alleles with a single nucleotide polymorphism (SNP) that alters the affinity of TATA-binding protein (TBP) for the TATA boxes of human gene promoters and (ii) PubMed to look for retrospective clinical reviews on changes in physiological indicators of reproductive potential in carriers of these alleles. RESULTS A total of 126 SNP markers of female reproductive potential, capable of altering the affinity of TBP for gene promoters, were found using the two above-mentioned Web services. For example, 10 candidate SNP markers of thrombosis (e.g., rs563763767) can cause overproduction of coagulation inducers. In pregnant women, Hughes syndrome provokes thrombosis with a fatal outcome although this syndrome can be diagnosed and eliminated even at the earliest stages of its development. Thus, in women carrying any of the above SNPs, preventive treatment of this syndrome before a planned pregnancy can reduce the risk of death. Similarly, seven SNP markers predicted here (e.g., rs774688955) can elevate the risk of myocardial infarction. In line with Bowles' lifespan theory, women carrying any of these SNPs may modify their lifestyle to improve their longevity if they can take under advisement that risks of myocardial infarction increase with age of the mother, total number of pregnancies, in multiple pregnancies, pregnancies under the age of 20, hypertension, preeclampsia, menstrual cycle irregularity, and in women smokers. CONCLUSIONS According to Bowles' lifespan theory-which links reproductive potential, quality of life, and life expectancy-the above information was compiled for those who would like to reduce risks of diseases corresponding to alleles in own sequenced genomes. Candidate SNP markers can focus the clinical analysis of unannotated SNPs, after which they may become useful for people who would like to bring their lifestyle in line with their sequenced individual genomes.
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Affiliation(s)
- Irina V Chadaeva
- Brain Neurobiology and Neurogenetics Center, Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 10 Lavrentyev Ave, Novosibirsk, 630090, Russia
- Novosibirsk State University, Novosibirsk, 630090, Russia
| | | | - Dmitry A Rasskazov
- Brain Neurobiology and Neurogenetics Center, Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 10 Lavrentyev Ave, Novosibirsk, 630090, Russia
| | - Ekaterina B Sharypova
- Brain Neurobiology and Neurogenetics Center, Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 10 Lavrentyev Ave, Novosibirsk, 630090, Russia
| | - Elena V Kashina
- Brain Neurobiology and Neurogenetics Center, Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 10 Lavrentyev Ave, Novosibirsk, 630090, Russia
| | - Dmitry A Zhechev
- Brain Neurobiology and Neurogenetics Center, Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 10 Lavrentyev Ave, Novosibirsk, 630090, Russia
| | - Irina A Drachkova
- Brain Neurobiology and Neurogenetics Center, Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 10 Lavrentyev Ave, Novosibirsk, 630090, Russia
| | - Olga V Arkova
- Brain Neurobiology and Neurogenetics Center, Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 10 Lavrentyev Ave, Novosibirsk, 630090, Russia
- Vector-Best Inc., Koltsovo, Novosibirsk Region, 630559, Russia
| | - Ludmila K Savinkova
- Brain Neurobiology and Neurogenetics Center, Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 10 Lavrentyev Ave, Novosibirsk, 630090, Russia
| | - Mikhail P Ponomarenko
- Brain Neurobiology and Neurogenetics Center, Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 10 Lavrentyev Ave, Novosibirsk, 630090, Russia.
- Novosibirsk State University, Novosibirsk, 630090, Russia.
| | - Nikolay A Kolchanov
- Brain Neurobiology and Neurogenetics Center, Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 10 Lavrentyev Ave, Novosibirsk, 630090, Russia
- Novosibirsk State University, Novosibirsk, 630090, Russia
| | - Ludmila V Osadchuk
- Brain Neurobiology and Neurogenetics Center, Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 10 Lavrentyev Ave, Novosibirsk, 630090, Russia
- Novosibirsk State Agricultural University, Novosibirsk, 630039, Russia
| | - Alexandr V Osadchuk
- Brain Neurobiology and Neurogenetics Center, Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 10 Lavrentyev Ave, Novosibirsk, 630090, Russia
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16
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Tanner JA, Tyndale RF. Variation in CYP2A6 Activity and Personalized Medicine. J Pers Med 2017; 7:jpm7040018. [PMID: 29194389 PMCID: PMC5748630 DOI: 10.3390/jpm7040018] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 11/17/2017] [Accepted: 11/27/2017] [Indexed: 12/16/2022] Open
Abstract
The cytochrome P450 2A6 (CYP2A6) enzyme metabolizes several clinically relevant substrates, including nicotine-the primary psychoactive component in cigarette smoke. The gene that encodes the CYP2A6 enzyme is highly polymorphic, resulting in extensive interindividual variation in CYP2A6 enzyme activity and the rate of metabolism of nicotine and other CYP2A6 substrates including cotinine, tegafur, letrozole, efavirenz, valproic acid, pilocarpine, artemisinin, artesunate, SM-12502, caffeine, and tyrosol. CYP2A6 expression and activity are also impacted by non-genetic factors, including induction or inhibition by pharmacological, endogenous, and dietary substances, as well as age-related changes, or interactions with other hepatic enzymes, co-enzymes, and co-factors. As variation in CYP2A6 activity is associated with smoking behavior, smoking cessation, tobacco-related lung cancer risk, and with altered metabolism and resulting clinical responses for several therapeutics, CYP2A6 expression and enzyme activity is an important clinical consideration. This review will discuss sources of variation in CYP2A6 enzyme activity, with a focus on the impact of CYP2A6 genetic variation on metabolism of the CYP2A6 substrates.
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Affiliation(s)
- Julie-Anne Tanner
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, ON M5T 1R8, Canada.
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada.
| | - Rachel F Tyndale
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, ON M5T 1R8, Canada.
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada.
- Department of Psychiatry, University of Toronto, Toronto, ON M5T 1R8, Canada.
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17
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Pérez-Rubio G, López-Flores LA, Ramírez-Venegas A, Noé-Díaz V, García-Gómez L, Ambrocio-Ortiz E, Sánchez-Romero C, Hernández-Zenteno RDJ, Sansores RH, Falfán-Valencia R. Genetic polymorphisms in CYP2A6 are associated with a risk of cigarette smoking and predispose to smoking at younger ages. Gene 2017; 628:205-210. [PMID: 28734893 DOI: 10.1016/j.gene.2017.07.051] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 07/03/2017] [Accepted: 07/17/2017] [Indexed: 10/19/2022]
Abstract
Nicotine is the main component of cigarettes that causes addiction, which is considered a complex disease, and genetic factors have been proposed to be involved in the development of addiction. The CYP2A6 gene encodes the main enzyme responsible for nicotine metabolism. Depending on the study population, different genetic variants of CYP2A6 associated with cigarette smoking have been described. Therefore, we evaluated the possible association between SNPs in CYP2A6 with cigarette smoking and nicotine addiction-related variables in Mexican mestizo smokers. We performed a genetic association study comparing light smokers (LS, n=349), heavy smokers (HS, n=351) and never-smokers (NS, n=394). SNPs rs1137115, rs4105144, rs1801272 and rs28399433 were genotyped in the CYP2A6 gene. We found that the A allele of rs1137115 (OR=1.41) in exon 1 of CYP2A6 and the T allele of rs4105144 (OR=1.32) in the 5' UTR of the gene are associated with the risk of cigarette smoking (p<0.05); rs1137115 affects the level of alternative splicing, resulting in a CYP2A6 isoform with low enzymatic activity, whereas rs4105144 is likely to be in a binding site for the transcription factor for glucocorticoids receptor (GR) and regulates the expression of CYP2A6. In addition, having a greater number of risk alleles (rs1137115 (A), rs4105144 (T) and rs28399433 (G)) is associated with a younger age at onset. The present study shows that in Mexican mestizos, the analyzed SNPs confer greater risk in terms of consumption and age of onset.
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Affiliation(s)
- Gloria Pérez-Rubio
- Laboratorio HLA, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Mexico City, Mexico
| | - Luis Alberto López-Flores
- Laboratorio HLA, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Mexico City, Mexico
| | - Alejandra Ramírez-Venegas
- Departamento de Investigación en Tabaquismo y EPOC, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Mexico City, Mexico
| | - Valeri Noé-Díaz
- Departamento de Investigación en Tabaquismo y EPOC, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Mexico City, Mexico
| | - Leonor García-Gómez
- Departamento de Investigación en Tabaquismo y EPOC, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Mexico City, Mexico
| | - Enrique Ambrocio-Ortiz
- Laboratorio HLA, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Mexico City, Mexico
| | - Candelaria Sánchez-Romero
- Departamento de Investigación en Tabaquismo y EPOC, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Mexico City, Mexico
| | - Rafael De Jesús Hernández-Zenteno
- Departamento de Investigación en Tabaquismo y EPOC, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Mexico City, Mexico
| | | | - Ramcés Falfán-Valencia
- Laboratorio HLA, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Mexico City, Mexico.
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18
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López-Flores LA, Pérez-Rubio G, Falfán-Valencia R. Distribution of polymorphic variants of CYP2A6 and their involvement in nicotine addiction. EXCLI JOURNAL 2017; 16:174-196. [PMID: 28507465 PMCID: PMC5427481 DOI: 10.17179/excli2016-847] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 02/13/2017] [Indexed: 01/08/2023]
Abstract
Tobacco consumption has become a major public health issue, which has motivated studies to identify and understand the biological processes involved in the smoking behavior for prevention and smoking cessation treatments. CYP2A6 has been identified as the main gene that codifies the enzyme that metabolizes nicotine. Many alleles have been identified after the discovery of CYP2A6, suggesting a wide interethnic variability and a diverse smoking behavior of the allele carrying individuals. The main purpose of this review is to update and highlight the effects of the CYP2A6 gene variability related to tobacco consumption reported from diverse human populations. The review further aims to consider CYP2A6 in future studies as a possible genetic marker for the prevention and treatment of nicotine addiction. Therefore, we analyzed several population studies and their importance at addressing and characterizing a population using specific parameters. Our efforts may contribute to a personalized system for detecting, preventing and treating populations at a higher risk of smoking to avoid diseases related to tobacco consumption.
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19
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Adehin A, Bolaji OO, Maggo S, Kennedy MA. Relationship between metabolic phenotypes and genotypes of CYP1A2 and CYP2A6 in the Nigerian population. Drug Metab Pers Ther 2017; 32:39-47. [PMID: 28231062 DOI: 10.1515/dmpt-2016-0041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 01/23/2017] [Indexed: 11/15/2022]
Abstract
BACKGROUND CYP1A2 and CYP2A6 are polymorphic drug-metabolising enzymes that are also implicated in the activation of procarcinogens in humans. Some of their alleles and haplotypes, often varied in prevalence across populations, are thought to influence activity despite the known contribution of environmental factors. This study assessed the potential influence of some genetic variants of CYP1A2 and CYP2A6 on metabolic phenotypes in Nigerians. METHODS Genomic DNA was extracted from blood samples of 100 healthy, unrelated subjects for whom CYP1A2 and CYP2A6 phenotypes had previously been determined, alongside an additional 80 other individuals for whom phenotype data were unavailable. The samples were screened for CYP1A2 (*1C,*1D,*1E,*1F, *3,*4,*6,*7) and CYP2A6 (*9,*11,*17) alleles using the Sequenom MassARRAY platform for some alleles and direct Sanger sequencing for others. The genetic data acquired were subsequently analysed for haplotypes and assessed for concordance with phenotypes. RESULTS All five CYP1A2 haplotypes (CYP1A2*1F, 1J, 1N, 1L, 1W) identified in the Nigerian population were not significantly predictive of metabolic phenotypes. Heterozygous CYP1A2*1J carriers and homozygous CYP1A2*1W carriers showed statistically insignificant decrease in CYP1A2 activity. The CYP2A6*9/*17 genotype was, however, significantly associated with the CYP2A6-poor metabolic phenotype, whereas CYP2A6*9 or CYP2A6*17 alone did not show any such association. CYP2A6*11 was not detected in the population. CONCLUSIONS Our findings suggest that CYP1A2 alleles or haplotypes were not predictive of metabolic phenotypes in the Nigerian population. Carriers of CYP2A6*9/*17 genotype are likely to be poor metabolisers of CYP2A6 substrates and may experience adverse reactions or poor efficacy while using drugs metabolised mainly by CYP2A6.
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20
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Tanner JA, Prasad B, Claw KG, Stapleton P, Chaudhry A, Schuetz EG, Thummel KE, Tyndale RF. Predictors of Variation in CYP2A6 mRNA, Protein, and Enzyme Activity in a Human Liver Bank: Influence of Genetic and Nongenetic Factors. J Pharmacol Exp Ther 2017; 360:129-139. [PMID: 27815364 PMCID: PMC5193072 DOI: 10.1124/jpet.116.237594] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 11/02/2016] [Indexed: 12/19/2022] Open
Abstract
Cytochrome P450 2A6 CYP2A6: metabolizes several clinically relevant substrates, including nicotine, the primary psychoactive component in cigarette smoke. Smokers vary widely in their rate of inactivation and clearance of nicotine, altering numerous smoking phenotypes. We aimed to characterize independent and shared impact of genetic and nongenetic sources of variation in CYP2A6 mRNA, protein, and enzyme activity in a human liver bank (n = 360). For the assessment of genetic factors, we quantified levels of CYP2A6, cytochrome P450 oxidoreductase (POR), and aldo-keto reductase 1D1 (AKR1D1) mRNA, and CYP2A6 and POR proteins. CYP2A6 enzyme activity was determined through measurement of cotinine formation from nicotine and 7-hydroxycoumarin formation from coumarin. Donor DNA was genotyped for CYP2A6, POR, and AKR1D1 genetic variants. Nongenetic factors assessed included gender, age, and liver disease. CYP2A6 phenotype measures were positively correlated to each other (r values ranging from 0.47-0.88, P < 0.001). Female donors exhibited higher CYP2A6 mRNA expression relative to males (P < 0.05). Donor age was weakly positively correlated with CYP2A6 protein (r = 0.12, P < 0.05) and activity (r = 0.20, P < 0.001). CYP2A6 reduced-function genotypes, but not POR or AKR1D1 genotypes, were associated with lower CYP2A6 protein (P < 0.001) and activity (P < 0.01). AKR1D1 mRNA was correlated with CYP2A6 mRNA (r = 0.57, P < 0.001), protein (r = 0.30, P < 0.001), and activity (r = 0.34, P < 0.001). POR protein was correlated with CYP2A6 activity (r = 0.45, P < 0.001). Through regression analyses, we accounted for 17% (P < 0.001), 37% (P < 0.001), and 77% (P < 0.001) of the variation in CYP2A6 mRNA, protein, and activity, respectively. Overall, several independent and shared sources of variation in CYP2A6 activity in vitro have been identified, which could translate to variable hepatic clearance of nicotine.
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Affiliation(s)
- Julie-Anne Tanner
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada (J-A.T., R.F.T.); Department of Pharmacology and Toxicology (J-A.T., R.F.T.) and Department of Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada; Department of Pharmaceutics (B.P., K.G.C, K.E.T.) and Center for Exposures, Diseases, Genomics, and Environment (P.S.), University of Washington, Seattle, Washington; Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee (A.C., E.G.S.)
| | - Bhagwat Prasad
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada (J-A.T., R.F.T.); Department of Pharmacology and Toxicology (J-A.T., R.F.T.) and Department of Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada; Department of Pharmaceutics (B.P., K.G.C, K.E.T.) and Center for Exposures, Diseases, Genomics, and Environment (P.S.), University of Washington, Seattle, Washington; Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee (A.C., E.G.S.)
| | - Katrina G Claw
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada (J-A.T., R.F.T.); Department of Pharmacology and Toxicology (J-A.T., R.F.T.) and Department of Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada; Department of Pharmaceutics (B.P., K.G.C, K.E.T.) and Center for Exposures, Diseases, Genomics, and Environment (P.S.), University of Washington, Seattle, Washington; Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee (A.C., E.G.S.)
| | - Patricia Stapleton
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada (J-A.T., R.F.T.); Department of Pharmacology and Toxicology (J-A.T., R.F.T.) and Department of Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada; Department of Pharmaceutics (B.P., K.G.C, K.E.T.) and Center for Exposures, Diseases, Genomics, and Environment (P.S.), University of Washington, Seattle, Washington; Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee (A.C., E.G.S.)
| | - Amarjit Chaudhry
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada (J-A.T., R.F.T.); Department of Pharmacology and Toxicology (J-A.T., R.F.T.) and Department of Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada; Department of Pharmaceutics (B.P., K.G.C, K.E.T.) and Center for Exposures, Diseases, Genomics, and Environment (P.S.), University of Washington, Seattle, Washington; Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee (A.C., E.G.S.)
| | - Erin G Schuetz
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada (J-A.T., R.F.T.); Department of Pharmacology and Toxicology (J-A.T., R.F.T.) and Department of Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada; Department of Pharmaceutics (B.P., K.G.C, K.E.T.) and Center for Exposures, Diseases, Genomics, and Environment (P.S.), University of Washington, Seattle, Washington; Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee (A.C., E.G.S.)
| | - Kenneth E Thummel
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada (J-A.T., R.F.T.); Department of Pharmacology and Toxicology (J-A.T., R.F.T.) and Department of Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada; Department of Pharmaceutics (B.P., K.G.C, K.E.T.) and Center for Exposures, Diseases, Genomics, and Environment (P.S.), University of Washington, Seattle, Washington; Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee (A.C., E.G.S.)
| | - Rachel F Tyndale
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada (J-A.T., R.F.T.); Department of Pharmacology and Toxicology (J-A.T., R.F.T.) and Department of Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada; Department of Pharmaceutics (B.P., K.G.C, K.E.T.) and Center for Exposures, Diseases, Genomics, and Environment (P.S.), University of Washington, Seattle, Washington; Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee (A.C., E.G.S.)
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Allenby CE, Boylan KA, Lerman C, Falcone M. Precision Medicine for Tobacco Dependence: Development and Validation of the Nicotine Metabolite Ratio. J Neuroimmune Pharmacol 2016; 11:471-83. [PMID: 26872457 PMCID: PMC5479354 DOI: 10.1007/s11481-016-9656-y] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 02/08/2016] [Indexed: 10/22/2022]
Abstract
Quitting smoking significantly reduces the risk of tobacco-related morbidity and mortality, yet there is a high rate of relapse amongst smokers who try to quit. Phenotypic biomarkers have the potential to improve smoking cessation outcomes by identifying the best available treatment for an individual smoker. In this review, we introduce the nicotine metabolite ratio (NMR) as a reliable and stable phenotypic measure of nicotine metabolism that can guide smoking cessation treatment among smokers who wish to quit. We address how the NMR accounts for sources of variation in nicotine metabolism including genotype and other biological and environmental factors such as estrogen levels, alcohol use, body mass index, or menthol exposure. Then, we highlight clinical trials that validate the NMR as a biomarker to predict therapeutic response to different pharmacotherapies for smoking cessation. Current evidence supports the use of nicotine replacement therapy for slow metabolizers, and non-nicotine treatments such as varenicline for normal metabolizers. Finally, we discuss future research directions to elucidate mechanisms underlying NMR associations with treatment response, and facilitate the implementation of the NMR as biomarker in clinical practice to guide smoking cessation.
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Affiliation(s)
- Cheyenne E Allenby
- Center for Interdisciplinary Research on Nicotine Addiction, Department of Psychiatry, University of Pennsylvania, 3535 Market Street, Suite 4100, Philadelphia, PA, 19104, USA
| | - Kelly A Boylan
- Center for Interdisciplinary Research on Nicotine Addiction, Department of Psychiatry, University of Pennsylvania, 3535 Market Street, Suite 4100, Philadelphia, PA, 19104, USA
| | - Caryn Lerman
- Center for Interdisciplinary Research on Nicotine Addiction, Department of Psychiatry, University of Pennsylvania, 3535 Market Street, Suite 4100, Philadelphia, PA, 19104, USA
| | - Mary Falcone
- Center for Interdisciplinary Research on Nicotine Addiction, Department of Psychiatry, University of Pennsylvania, 3535 Market Street, Suite 4100, Philadelphia, PA, 19104, USA.
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22
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Wassenaar CA, Zhou Q, Tyndale RF. CYP2A6 genotyping methods and strategies using real-time and end point PCR platforms. Pharmacogenomics 2015; 17:147-62. [PMID: 26670214 DOI: 10.2217/pgs.15.156] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
CYP2A6 genotyping is of clinical importance--CYP2A6 gene variants influence nicotine metabolism and are associated with nicotine dependence, cigarettes per day, smoking cessation and the risk for tobacco-associated cancers. CYP2A6 gene variants also influence the metabolism of therapeutic drugs, such as the anticancer agents, tegafur and letrozole. Over the years, CYP2A6 genotyping methods have evolved to incorporate novel gene variants and to circumvent genotyping errors resulting from the high degree of homology between CYP2A6 and neighboring CYP2A genes. Herein, CYP2A6 genotyping strategies are described for commonly genotyped functionally significant alleles including SNPs, small insertions/deletions and more complex structural variants. The methods presented utilize higher throughput SYBR green real-time PCR technology in addition to standard thermocycling.
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Affiliation(s)
- Catherine A Wassenaar
- Department of Pharmacology & Toxicology, University of Toronto, 1 King's College Circle, Toronto, M5S 1A8 ON, Canada
| | - Qian Zhou
- Department of Pharmacology & Toxicology, University of Toronto, 1 King's College Circle, Toronto, M5S 1A8 ON, Canada
| | - Rachel F Tyndale
- Campbell Family Mental Health Research Institute, Centre for Addiction & Mental Health (CAMH), Departments of Pharmacology & Toxicology & Psychiatry, University of Toronto, 1 King's College Circle, Toronto, M5S 1A8 ON, Canada
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Ponomarenko M, Rasskazov D, Arkova O, Ponomarenko P, Suslov V, Savinkova L, Kolchanov N. How to Use SNP_TATA_Comparator to Find a Significant Change in Gene Expression Caused by the Regulatory SNP of This Gene's Promoter via a Change in Affinity of the TATA-Binding Protein for This Promoter. BIOMED RESEARCH INTERNATIONAL 2015; 2015:359835. [PMID: 26516624 PMCID: PMC4609514 DOI: 10.1155/2015/359835] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 08/24/2015] [Indexed: 01/11/2023]
Abstract
The use of biomedical SNP markers of diseases can improve effectiveness of treatment. Genotyping of patients with subsequent searching for SNPs more frequent than in norm is the only commonly accepted method for identification of SNP markers within the framework of translational research. The bioinformatics applications aimed at millions of unannotated SNPs of the "1000 Genomes" can make this search for SNP markers more focused and less expensive. We used our Web service involving Fisher's Z-score for candidate SNP markers to find a significant change in a gene's expression. Here we analyzed the change caused by SNPs in the gene's promoter via a change in affinity of the TATA-binding protein for this promoter. We provide examples and discuss how to use this bioinformatics application in the course of practical analysis of unannotated SNPs from the "1000 Genomes" project. Using known biomedical SNP markers, we identified 17 novel candidate SNP markers nearby: rs549858786 (rheumatoid arthritis); rs72661131 (cardiovascular events in rheumatoid arthritis); rs562962093 (stroke); rs563558831 (cyclophosphamide bioactivation); rs55878706 (malaria resistance, leukopenia), rs572527200 (asthma, systemic sclerosis, and psoriasis), rs371045754 (hemophilia B), rs587745372 (cardiovascular events); rs372329931, rs200209906, rs367732974, and rs549591993 (all four: cancer); rs17231520 and rs569033466 (both: atherosclerosis); rs63750953, rs281864525, and rs34166473 (all three: malaria resistance, thalassemia).
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Affiliation(s)
- Mikhail Ponomarenko
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
| | - Dmitry Rasskazov
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Olga Arkova
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Petr Ponomarenko
- Children's Hospital Los Angeles, University of Southern California, Los Angeles, CA 90027, USA
| | - Valentin Suslov
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Ludmila Savinkova
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Nikolay Kolchanov
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
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Svyryd Y, Ramírez-Venegas A, Sánchez-Hernández B, Aguayo-Gómez A, Luna-Muñoz L, Arteaga-Vázquez J, Regalado-Pineda J, Mutchinick OM. Genetic Risk Determinants for Cigarette Smoking Dependence in Mexican Mestizo Families. Nicotine Tob Res 2015; 18:620-5. [PMID: 26416825 DOI: 10.1093/ntr/ntv213] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 09/12/2015] [Indexed: 01/13/2023]
Abstract
INTRODUCTION Tobacco smoking is a leading cause of mortality in developed and developing countries. Despite antitobacco and smoke-free policies, the prevalence of active smokers in Mexican urban populations has remained stable. Mexican smokers differ from Caucasian and other ethnic groups, probably due to sociocultural and genetic background characteristics. This study explored the effect of known genetic variants on smoking behavior in Mexico City residents. METHODS Three hundred sixty-four Mexican Mestizo Mexico City residents from 87 families with at least one smoker were assessed for association of 12 gene variants of six candidate genes (CHRNA4, CHRNB2, DRD2, ANKK1, SLC6A3, and CYP2A6) with cigarette consumption, age of initiation and smoking duration. The Family Based Association Test, an extension of the Transmission Disequilibrium Test, was used to perform family-based association analysis. RESULTS The Family Based Association Test showed statistically significant association between the rs2072658 polymorphism of the CHRNB2 gene and smoking-related phenotypes such as: smoking status (SS), age of onset (AO), years of smoking, and psychological dependence (PD) evaluated by the Glover-Nilsson Smoking Behavior Questionnaire. After Bonferroni correction, only the association with AO remained significant (P = .003). Statistically significant association was also observed for the CYP2A6 rs28399433 T allele with SS (P = .003) and PD (P = .003). CONCLUSIONS Our results indicate effects of the rs2072658 CHRNB2 and rs28399433 CYP2A6 gene variants on AO, SS and PD in Mexican Mestizo smokers. A mild effect of other analyzed gene variants, which may contribute to a putative polygenic predisposition for smoking, is suggested. IMPLICATIONS The understanding of genetic and environmental determinants in the Mexican population is important for other Latin American populations as well, living in their own countries or moving to other ones, particular due to the current migration characteristics and particular genetic background like the Mexican Mestizo and other Central American populations with similar characteristics and migrating to neighbor developed countries, introducing their own smoking behavior and contributing importantly to the genetic pool of the receptor country.
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Affiliation(s)
- Yevgeniya Svyryd
- Departament of Genetics, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", México, D.F., México
| | - Alejandra Ramírez-Venegas
- Department of Smoking Research, Instituto Nacional de Enfermedades Respiratorias, México, D.F., México
| | - Beatriz Sánchez-Hernández
- Departament of Genetics, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", México, D.F., México
| | - Adolfo Aguayo-Gómez
- Departament of Genetics, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", México, D.F., México
| | - Leonora Luna-Muñoz
- Departament of Genetics, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", México, D.F., México
| | - Jazmín Arteaga-Vázquez
- Departament of Genetics, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", México, D.F., México
| | | | - Osvaldo M Mutchinick
- Departament of Genetics, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", México, D.F., México;
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Liu JH, Xun XJ, Pang C, Ma J, Zou H, Chen C, Dai PG. Single tube genotyping of CYP2A6 gene deletion based on copy number determination by quantitative real-time PCR. Exp Mol Pathol 2014; 97:529-34. [PMID: 25446842 DOI: 10.1016/j.yexmp.2014.10.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 10/28/2014] [Indexed: 10/24/2022]
Abstract
The CYP2A6*4 allele, characterized as the whole deletion of this gene, is closely associated with nicotine dependence, cancer susceptibility, and drug responsiveness. It has long been a significant challenge for pharmacogenetics scientists to develop a reliable method to detect this molecular variant due to its high homology with its homologous genes CYP2A6 and CYP2A3 in the clinical setting. Here, we introduce a quantitative real-time PCR assay that specifically amplifies CYP2A6 by designing a specific set of primers and the probe, which effectively prevent the amplification of the CYP2A7 and CYP2A13 alleles. CYP2A6 gene copy numbers were normalized to albumin (ALB) which was co-amplified simultaneously in a single-tube duplex reaction and at a setting as the internal reference gene. The established assay was validated with a selection of previously genotyped DNA samples, which harbored none, one or two CYP2A6 gene copies. The results were in complete concordance with previously published data and no overlap between the three groups was observed. Further analysis of a cohort of 120 samples revealed high specificity and sensitivity of this assay as demonstrated by the agreement of determined gene copy numbers in all of the cases. In conclusion, this novel assay allows reliable and sensitive detection of the CYP2A6 gene deletion, which will be useful for pharmacogenetics studies and routine clinical settings.
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Affiliation(s)
- Jin-hui Liu
- National Engineering Research Center for Miniaturized Detection Systems, School of Life Sciences, Northwest University, Xi'an, PR China
| | - Xiao-jie Xun
- National Engineering Research Center for Miniaturized Detection Systems, School of Life Sciences, Northwest University, Xi'an, PR China
| | - Cong Pang
- National Engineering Research Center for Miniaturized Detection Systems, School of Life Sciences, Northwest University, Xi'an, PR China
| | - Jun Ma
- National Engineering Research Center for Miniaturized Detection Systems, School of Life Sciences, Northwest University, Xi'an, PR China
| | - Hui Zou
- National Engineering Research Center for Miniaturized Detection Systems, School of Life Sciences, Northwest University, Xi'an, PR China
| | - Chao Chen
- National Engineering Research Center for Miniaturized Detection Systems, School of Life Sciences, Northwest University, Xi'an, PR China
| | - Peng-gao Dai
- National Engineering Research Center for Miniaturized Detection Systems, School of Life Sciences, Northwest University, Xi'an, PR China.
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Haas DW, Kwara A, Richardson DM, Baker P, Papageorgiou I, Acosta EP, Morse GD, Court MH. Secondary metabolism pathway polymorphisms and plasma efavirenz concentrations in HIV-infected adults with CYP2B6 slow metabolizer genotypes. J Antimicrob Chemother 2014; 69:2175-82. [PMID: 24729586 DOI: 10.1093/jac/dku110] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
OBJECTIVES Efavirenz is widely prescribed for HIV-1 infection, and CYP2B6 polymorphisms 516G→T and 983T→C define efavirenz slow metabolizer genotypes. To identify genetic predictors of higher plasma efavirenz concentrations beyond these two common functional alleles, we characterized associations with mid-dosing interval efavirenz concentrations in 84 HIV-infected adults, all carrying two copies of these major loss-of-function CYP2B6 alleles. METHODS Study participants had been randomized to efavirenz-containing regimens in prospective clinical trials and had available plasma efavirenz assay data. Analyses focused on secondary metabolism pathway polymorphisms CYP2A6 -48T→G (rs28399433), UGT2B7 735A→G (rs28365062) and UGT2B7 802T→C (rs7439366). Exploratory analyses also considered 196 polymorphisms and 8 copy number variants in 41 drug metabolism/transport genes. Mid-dosing interval efavirenz concentrations at steady-state were obtained ≥8 h but <19 h post-dose. Linear regression was used to test for associations between polymorphisms and log-transformed efavirenz concentrations. RESULTS Increased efavirenz concentrations were associated with CYP2A6 -48T→G in all subjects (P = 3.8 × 10(-4)) and in Black subjects (P = 0.027) and White subjects (P = 0.0011) analysed separately; and with UGT2B7 735 G/G homozygosity in all subjects (P = 0.006) and in Black subjects (P = 0.046) and White subjects (P = 0.062) analysed separately. In a multivariable model, CYP2A6 -48T→G and UGT2B7 735 G/G homozygosity remained significant (P < 0.05 for each). No additional polymorphisms or copy number variants were significantly associated with efavirenz concentrations. CONCLUSIONS Among individuals with a CYP2B6 slow metabolizer genotype, CYP2A6 and possibly UGT2B7 polymorphisms contribute to even higher efavirenz concentrations.
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Affiliation(s)
- David W Haas
- Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Awewura Kwara
- Warren Alpert Medical School of Brown University, Providence, RI, USA
| | | | - Paxton Baker
- Vanderbilt University School of Medicine, Nashville, TN, USA
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Aklillu E, Djordjevic N, Carrillo JA, Makonnen E, Bertilsson L, Ingelman-Sundberg M. High CYP2A6 enzyme activity as measured by a caffeine test and unique distribution of CYP2A6 variant alleles in Ethiopian population. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2013; 18:446-53. [PMID: 24380444 DOI: 10.1089/omi.2013.0140] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
CYP2A6 metabolizes clinically relevant drugs, including antiretroviral and antimalarial drugs of major public health importance for the African populations. CYP2A6 genotype-phenotype relationship in African populations, and implications of geographic differences on enzyme activity, remain to be investigated. We evaluated the influence of CYP2A6 genotype, geographical differences, gender, and cigarette smoking on enzyme activity, using caffeine as a probe in 100 healthy unrelated Ethiopians living in Ethiopia, and 72 living in Sweden. CYP2A6 phenotype was estimated by urinary 1,7-dimethyluric acid (17U)/1,7-dimethylxanthine or paraxanthine (17X) ratio. The frequencies of CYP2A6*1B, *1D, *2, *4, *9, and *1x2 in Ethiopians were 31.3, 29.4, 0.6, 0.6, 2.8, and 0.3%, respectively. The overall mean±SD for log 17U/17X was 0.12±0.24 and coefficient of variation 199%. No significant difference in the mean log 17U/17X ratio between Ethiopians living in Sweden versus Ethiopia was observed. Analysis of variance revealed CYP2A6 genotype (p=0.04, F=2.01) but not geographical differences, sex, or cigarette smoking as predictors of CYP2A6 activity. Importantly, the median (interquartile range) of 17U/17X ratio in Ethiopians 1.35 (0.99 to 1.84) was 3- and 11-fold higher than the previously reported value in Swedes 0.52 (0.27 to 1.00) and Koreans 0.13 (0.0 to 0.35), respectively (Djordjevic et al., 2013). Taken together, we report here the relevance of CYP2A6 genotype for enzyme activity in this Ethiopian sample, as well as high CYP2A6 activity and unique distribution of the CYP2A6 variant alleles in Ethiopians as compared other populations described hitherto. Because Omics biomarker research is rapidly accelerating in Africa, CYP2A6 pharmacogenetics and clinical pharmacology observations reported herein for the Ethiopian populations have clinical and biological importance to plan for future rational therapeutics efforts in the African continent as well as therapeutics as a global science.
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Affiliation(s)
- Eleni Aklillu
- 1 Division of Clinical Pharmacology, Department of Laboratory Medicine, Karolinska University Hospital , Karolinska Institutet, Stockholm, Sweden
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PharmGKB summary: very important pharmacogene information for cytochrome P-450, family 2, subfamily A, polypeptide 6. Pharmacogenet Genomics 2013; 22:695-708. [PMID: 22547082 DOI: 10.1097/fpc.0b013e3283540217] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Djordjevic N, Carrillo JA, van den Broek MP, Kishikawa J, Roh HK, Bertilsson L, Aklillu E. Comparisons of CYP2A6 Genotype and Enzyme Activity between Swedes and Koreans. Drug Metab Pharmacokinet 2013; 28:93-7. [DOI: 10.2133/dmpk.dmpk-12-rg-029] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Sharma A, Dinesh K, Yadav S, Jain SK, Pant MC, Parmar D. Cytochrome P450 2A isoenzymes in freshly prepared blood lymphocytes isolated from rats and validation as a biomarker for clinical studies in humans. Xenobiotica 2012; 43:311-9. [PMID: 22934830 DOI: 10.3109/00498254.2012.717728] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
1. The present study aimed to identify the expression of carcinogen metabolizing cytochrome P4502A (CYP2A) isoenzymes in freshly prepared rat peripheral blood lymphocytes (PBL) isolated from adult rats and investigate similarities in the regulation of lymphocyte CYP2A-isoenzymes with the tissue enzyme. 2. qRT-PCR studies demonstrated significant constitutive mRNA expression of CYP2A-isoenzymes in PBL isolated from male and female rats which further increases significantly after pretreatment with nicotine or 3-methylcholanthrene (MC) indicating responsiveness of CYP2A-isoenzymes in PBL. This increase in the CYP2A expression was associated with an increase in the protein expression and CYP2A3-dependent coumarin hydroxylase (COH) activity in PBL. 3. Clinical studies further demonstrated significant increase in the expression of CYP2A6 and associated enzyme activity in PBL isolated from lung cancer patients. Our data thus provided evidence for similarities in the regulation of carcinogen metabolizing CYP2A-isoenzymes in PBL with the tissue enzymes. Further, responsiveness of blood CYP2A6 in human blood lymphocytes isolated from lung cancer patients has led us to suggest that associating expression profiles of CYP2A6 and other polycyclic aromatic hydrocarbons (PAH)-responsive CYPs in PBL with the genotyping data could lead to the development of a possible screen to monitor and predict environment-induced diseases and toxicity in humans.
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Affiliation(s)
- Amit Sharma
- Developmental Toxicology Division, Indian Institute of Toxicology Research (Council of Scientific and Industrial Research), Lucknow, UP, India
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Da Silva FR, Da Silva J, Nunes E, Benedetti D, Kahl V, Rohr P, Abreu MB, Thiesen FV, Kvitko K. Application of the buccal micronucleus cytome assay and analysis of PON1Gln192Arg and CYP2A6*9(-48T>G) polymorphisms in tobacco farmers. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2012; 53:525-34. [PMID: 22847926 DOI: 10.1002/em.21713] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Accepted: 05/31/2012] [Indexed: 06/01/2023]
Abstract
Tobacco is a major Brazilian cash crop. Tobacco farmers apply large amounts of pesticides to control insect growth. Workers come into contact with green tobacco leaves during the tobacco harvest and absorb nicotine through the skin. In the present study, micronucleus frequency, cell death, and the frequency of basal cells were measured in tobacco farmers using the buccal micronucleus cytome assay (BMCyt), in parallel with measurement of blood butyrylcholinesterase (BChE) and nicotine levels. Polymorphisms in PONIGln192Arg and CYP2A6*9(-48T>G) were evaluated to verify the relationship between genetic susceptibility and the measured biomarkers. Peripheral blood and buccal cell samples were collected from 106 agricultural workers, at two different crop times (during pesticide application and leaf harvest), as well as 53 unexposed controls. BMCyt showed statistically significant increases in micronuclei, nuclear buds, and binucleated cells among exposed subjects in differentiated cells, and in micronuclei in basal cells. In addition, the exposed group showed higher values for condensed chromatin, karyorrhectic, pyknotic, and karyolitic cells, indicative of cell death, and an increase in the frequency of basal cells compared to the unexposed control group. A slight difference in mutagenicity using the BMCyt assay was found between the two different sampling times (pesticide application and leaf harvest), with higher micronucleus frequencies during pesticide application. Elevated cotinine levels were observed during the leaf harvest compared to the unexposed controls, while BChE level was similar among the farmers and controls. PONIGln192Arg and CYP2A6*9(-48T>G) polymorphisms were associated with DNA damage induced by pesticides and cell death.
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Affiliation(s)
- Fernanda Rabaioli Da Silva
- Department of Genetics and Molecular Biology, Postgraduate Program in Genetics and Molecular Biology (PPGBM), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre-RS, Brazil
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Da Silva FR, Da Silva J, Allgayer MDC, Simon CF, Dias JF, dos Santos CEI, Salvador M, Branco C, Schneider NB, Kahl V, Rohr P, Kvitko K. Genotoxic biomonitoring of tobacco farmers: Biomarkers of exposure, of early biological effects and of susceptibility. JOURNAL OF HAZARDOUS MATERIALS 2012; 225-226:81-90. [PMID: 22614024 DOI: 10.1016/j.jhazmat.2012.04.074] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 04/23/2012] [Accepted: 04/27/2012] [Indexed: 06/01/2023]
Abstract
Tobacco farming presents several hazards to those who cultivate and harvest the plant. The genotoxic and mutagenic effects in tobacco farmers were investigated. In order to verify the relationship between genetic susceptibility and biomarkers GSTT1, GSTM1, GSTP1, CYP2A6, PON, OGG1, RAD51, XRCC1, and XRCC4 genes polymorphism were evaluated. Oxidative stress markers and trace elements content were determined. Peripheral blood cells samples were collected from 111 agricultural workers during pesticides application and leaf harvest, and 56 non-exposed subjects. Results show that farmers are exposed to mixture of substances with genotoxic and cytotoxic potential. Only GSTM1 null and CYP2A6*9 showed significant associations with cytokinesis-blocked micronuclei assay results. In pesticide application an increase in trace elements content was observed. The results indicated that exposure to pesticides and nicotine can influence antioxidant enzymes activity. Our study drives the attention once more to the need for occupational training on safe work environment for farm workers.
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Affiliation(s)
- Fernanda Rabaioli Da Silva
- Postgraduate Program in Genetics and Molecular Biology, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
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Abstract
Pharmacogenomics is moving from a candidate gene strategy to large scale approaches. This is in line with the new paradigm of linking a trait to (a) pathway(s) rather than to single genes. In addition, breakthroughs in genomics offer a non-a priori assessment of implicated genes, expanding the possibilities in pharmacogenomics research. In this review, we discuss the pros and cons of new concepts in study design and on high throughput approaches to be implemented in the near future.
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Affiliation(s)
- Julia di Iulio
- Institute of Microbiology, University Hospital, University of Lausanne Lausanne, Switzerland.
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Yusof W, Hua GS. Gene, ethnic and gender influences predisposition of adverse drug reactions to artesunate among Malaysians. Toxicol Mech Methods 2011; 22:184-92. [PMID: 22003869 DOI: 10.3109/15376516.2011.623331] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
CONTEXT Artesunate (AS) and amodiaquine (AQ) are two prodrugs widely used as antimalarial agents and are metabolized by the CYP P450 2A6 (CYP 2A6) and CYP P450 2C8 (CYP 2C8) enzymes, respectively. OBJECTIVE In this study, we aim to investigate the association of both genes on AS and AQ's tolerabilities in the hope of identifying a pharmacogenetic approach that could be useful in prediction and prevention of adverse drug reactions (ADRs) among Malaysian population. MATERIALS AND METHODS In this randomized crossover study, loose and AS/AQ formulations were administered to normal healthy volunteers (n = 24) over two study phases. The drugs' tolerabilities (incidence of facial flushing, giddiness, headache, nausea, abdominal discomfort, progression of liver enzymes and neutrophil counts) were compared between the two treatment arms. Volunteers were also genotyped for the CYP2C8 and CYP2A6 variants. RESULTS The frequency of the CYP2A6*1B, CYP2A6*4, CYP2A6*8 and CYP2A6*9 alleles were 54.2%, 16.7%, 4.2% and 10.4%, respectively. No mutations for CYP2C8 gene were, however, detected. Most (96%) of the subjects were of the Malay ethnicity. Subjects having the CYP2A6*1B variants responsible for ultra rapid metabolism of AS suffered a significantly higher incidence of ADRs. DISCUSSION Our study is the first to report that CYP2A6 genotyping influences AS's ADR. Gender also plays a role where females reported more incidences of nausea (p < 0.05). CONCLUSION It is concluded that genetic polymorphisms of CYP2A6 as well as gender influence the side effect profiles of subjects receiving AS among this Malaysian population.
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Affiliation(s)
- Wardah Yusof
- Department of Pharmacology, School of Medical Sciences, Health Campus, Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia
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Functional evaluation of genetic and environmental regulators of p450 mRNA levels. PLoS One 2011; 6:e24900. [PMID: 21998633 PMCID: PMC3187744 DOI: 10.1371/journal.pone.0024900] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Accepted: 08/19/2011] [Indexed: 11/19/2022] Open
Abstract
Variations in the activities of Cytochrome P450s are one of the major factors responsible for inter-individual differences in drug clearance rates, which may cause serious toxicity or inefficacy of therapeutic drugs. Various mRNA level is one of the key factors for different activity of the major P450 genes. Although both genetic and environmental regulators of P450 gene expression have been widely investigated, few studies have evaluated the functional importance of cis- and trans-regulatory factors and environmental factors in the modulation of inter-individual expression variations of the P450 genes. In this study, we measured the mRNA levels of seven major P450 genes (CYP1A1, CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP3A4 and CYP3A5) in 96 liver biopsy samples from Chinese population. Both trans-acting (mRNA levels and non-synonymous SNPs of putative regulator genes) and cis-acting (gene copy number and functional SNPs) factors were investigated to identify the determinants of the expression variations of these seven P450 genes. We found that expression variations of most P450 genes, regulator genes and housekeeping genes were positively correlated at the mRNA level. After partial correlation analysis using ACTB and GAPDH expression to eliminate the effect of global regulators, a UPGMA (Unweighted Pair Group Method with Arithmetic Mean) tree was constructed to reveal the effects of specific regulation networks potentially masked by global regulators. Combined with the functional analysis of regulators, our results suggested that expression variation at the mRNA level was mediated by several factors in a gene-specific manner. Cis-acting genetic variants might play key roles in the expression variation of CYP2D6 and CYP3A5, environmental inducers might play key roles in CYP1A1 and CYP1A2 variation and global regulators might play key roles in CYP2C9 variation. In addition, the functions of regulators that play less important roles in controlling expression variation for each P450 gene were determined.
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Liu T, David SP, Tyndale RF, Wang H, Zhou Q, Ding P, He YH, Yu XQ, Chen W, Crump C, Wen XZ, Chen WQ. Associations of CYP2A6 genotype with smoking behaviors in southern China. Addiction 2011; 106:985-94. [PMID: 21205058 PMCID: PMC3074015 DOI: 10.1111/j.1360-0443.2010.03353.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIMS To investigate the association of CYP2A6 genetic polymorphisms with smoking-related phenotypes in Chinese smokers. DESIGN Case-only genetic association study. SETTING Southern China. PARTICIPANTS A total of 1328 Han Chinese smokers who participated in a community-based chronic disease screening project in Guangzhou and Zhuhai from 2006 to 2007. MEASUREMENTS All participants answered a structured questionnaire about socio-demographic status and smoking behaviors and informative alleles were genotyped for the cytochrome P450 2A6 (CYP2A6) gene (CYP2A6*4,*5,*7,*9 and *10). FINDINGS The frequencies of CYP2A6*4, *5, *7, *9 and *10 alleles were 8.5, 1.2, 6.3, 13.5 and 2.4%, which corresponded to 48.9, 15.4, 24.2 and 11.5% of participants being classified as normal, intermediate, slow and poor metabolizers, respectively. Multivariate analyses in male smokers demonstrated that compared with normal metabolizers, poor metabolizers reported smoking fewer cigarettes per day [adjusted odds ratio (OR) = 0.49; 95% confidence interval (CI): 0.32-0.76], started smoking regularly later in life (adjusted OR = 1.55; 95% CI: 1.06-2.26) and, among former smokers, reported smoking for a shorter duration prior to quitting (adjusted OR = 0.33; 95% CI: 0.12-0.94). However, poor metabolizers were less likely to quit smoking and remain abstinent than normal metabolizers (adjusted OR = 0.54; 95% CI: 0.34-0.86). CONCLUSIONS Reduced metabolism function of cytochrome P450 2A6 in smokers appears to be associated with fewer cigarettes smoked, later initiation of smoking regularly, shorter smoking duration and lower likelihood of smoking cessation.
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Affiliation(s)
- Tao Liu
- Department of Biostatistics and Epidemiology, School of Public Health, Sun Yat-Sen University, 74, Zhongshan Road 2, 510080, Guangzhou, China
| | - Sean P. David
- Center for Education in Family & Community Medicine and the Division of Family & Community Medicine, Stanford University, 1215 Welch Road, Modular G, Stanford, CA 94305, USA, SRI International, 333 Ravenswood Ave, Menlo Park, CA 943025, USA, Center for Primary Care & Prevention and the Department of Family Medicine, Brown Alpert Medical School, 111 Brewster Street, Pawtucket, RI 02860
| | - Rachel F. Tyndale
- The Center for Addiction and Mental Health and the Departments of Psychiatry, Pharmacology and Toxicology, University of Toronto, Canada M5S 1A8
| | - Hui Wang
- Department of Biostatistics and Epidemiology, School of Public Health, Sun Yat-Sen University, 74, Zhongshan Road 2, 510080, Guangzhou, China
| | - Qian Zhou
- The Center for Addiction and Mental Health and the Departments of Psychiatry, Pharmacology and Toxicology, University of Toronto, Canada M5S 1A8
| | - Peng Ding
- Department of Biostatistics and Epidemiology, School of Public Health, Sun Yat-Sen University, 74, Zhongshan Road 2, 510080, Guangzhou, China
| | - Yan-Hui He
- Department of Biostatistics and Epidemiology, School of Public Health, Sun Yat-Sen University, 74, Zhongshan Road 2, 510080, Guangzhou, China
| | - Xue-Qing Yu
- Department of Nephrology, The First Affiliated Hospital of Sun Yat-Sen University, 58, Zhongshan Road 2, 510080, Guangzhou, China
| | - Wei Chen
- Department of Nephrology, The First Affiliated Hospital of Sun Yat-Sen University, 58, Zhongshan Road 2, 510080, Guangzhou, China
| | - Casey Crump
- Center for Education in Family & Community Medicine and the Division of Family & Community Medicine, Stanford University, 1215 Welch Road, Modular G, Stanford, CA 94305, USA
| | - Xiao-Zhong Wen
- Department of Community Health, Brown University, Providence, RI, USA
| | - Wei-Qing Chen
- Department of Biostatistics and Epidemiology, School of Public Health, Sun Yat-Sen University, 74, Zhongshan Road 2, 510080, Guangzhou, China,To whom correspondence should be addressed. Tel: +8620 87332199; Fax: +8620 87330446, (Wei-Qing Chen)
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Soriano A, Vicente J, Carcas C, Gonzalez-Andrade F, Arenaz I, Martinez-Jarreta B, Fanlo A, Mayayo E, Sinués B. Differences between Spaniards and Ecuadorians in CYP2A6 allele frequencies: comparison with other populations. Fundam Clin Pharmacol 2011; 25:627-32. [DOI: 10.1111/j.1472-8206.2010.00889.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Drachkova IA, Ponomarenko PM, Arshinova TV, Ponomarenko МP, Suslov VV, Savinkova LK, Kolchanov NА. In vitro examining the existing prognoses how TBP binds to TATA with SNP associated with human diseases. Health (London) 2011. [DOI: 10.4236/health.2011.39099] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Ponomarenko PM, Suslov VV, Savinkova LK, Ponomarenko MP, Kolchanov NA. A precise equation of equilibrium of four steps of TBP binding with the TATA box for prognosis of phenotypic manifestation of mutations. Biophysics (Nagoya-shi) 2010. [DOI: 10.1134/s0006350910030036] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Al Koudsi N, Hoffmann EB, Assadzadeh A, Tyndale RF. Hepatic CYP2A6 levels and nicotine metabolism: impact of genetic, physiological, environmental, and epigenetic factors. Eur J Clin Pharmacol 2009; 66:239-51. [PMID: 20012030 DOI: 10.1007/s00228-009-0762-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Accepted: 11/10/2009] [Indexed: 11/26/2022]
Abstract
PURPOSE We investigated the role of genetic, physiological, environmental, and epigenetic factors in regulating CYP2A6 expression and nicotine metabolism. METHODS Human livers (n = 67) were genotyped for CYP2A6 alleles and assessed for nicotine metabolism and CYP2A6 expression (mRNA and protein). In addition, a subset of livers (n = 18), human cryopreserved hepatocytes (n = 2), and HepG2 cells were used for DNA methylation analyses. RESULTS Liver samples with variant CYP2A6 alleles had significantly lower CYP2A6 protein expression, nicotine C-oxidation activity, and affinity for nicotine. Female livers had significantly higher CYP2A6 protein and mRNA expression compared to male livers. Livers exposed to dexamethasone and phenobarbital had higher CYP2A6 expression and activity, however the difference was not statistically significant. Age and DNA methylation status of the CpG island and a regulatory site were not associated with altered CYP2A6. CONCLUSIONS We identified genotype, gender, and exposure to inducers as sources of variation in CYP2A6 expression and activity, but much variation remains to be accounted for.
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Affiliation(s)
- Nael Al Koudsi
- Department of Pharmacology and Toxicology, University of Toronto, ON, Canada
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Can the 2-(13)C-uracil breath test be used to predict the effect of the antitumor drug S-1? Cancer Chemother Pharmacol 2009; 66:333-43. [PMID: 19921195 DOI: 10.1007/s00280-009-1168-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Accepted: 10/27/2009] [Indexed: 10/20/2022]
Abstract
PURPOSE S-1 is an oral anticancer drug containing tegafur (FT), a pro-drug of fluorouracil, combined with two modulators, 5-chloro-2,4-dihydroxypyridine and potassium oxonate (Oxo), at a molar ratio of 1:0.4:1. CYP2A6 genetic polymorphism and dihydropyrimidine dehydrogenase (DPD) inhibition are important for the antitumor effect of S-1. Exploiting the usefulness of the 2-(13)C-uracil breath test (UrBT) as an indicator of DPD activity, we examined whether the results of CYP2A6 genetic polymorphism analysis and UrBT could be used to predict the antitumor effect of S-1. METHODS Thirty-four patients with advanced or recurrent cancer (15, 16 and 3 with gastric, colorectal and pancreatic cancer, respectively) were orally administered 40 mg/m(2) S-1 twice daily in the morning and evening. Eighteen patients with a complete response (CR)/partial response (PR) (2 with CR, 16 with PR) and 16 with progressive disease (PD) were compared with respect to CYP2A6 genetic polymorphisms (1- vs. 2-allele mutation), UrBT results, and plasma FT and 5-fluorouracil levels at 3 h after S-1 ingestion in the morning. RESULTS On multivariate analysis between the CR/PR and PD groups, only the UrBT results was an independent factor of CR/PR to S-1 (95% CI 1.02-1.10). CONCLUSION These results suggest that the anticancer effect of S-1 can be predicted by performing UrBT 3 h after the initial oral S-1 administration.
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Apinan R, Tassaneeyakul W, Mahavorasirikul W, Satarug S, Kajanawart S, Vannaprasaht S, Ruenweerayut R, Na-Bangchang K. The influence of CYP2A6 polymorphisms and cadmium on nicotine metabolism in Thai population. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2009; 28:420-424. [PMID: 21784037 DOI: 10.1016/j.etap.2009.07.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Revised: 07/01/2009] [Accepted: 07/02/2009] [Indexed: 05/31/2023]
Abstract
We investigated the influence of genetic, cadmium exposure and smoking status, on cytochrome P450-mediated nicotine metabolism (CYP2A6) in 182 Thai subjects after receiving 2mg of nicotine gum chewing for 30min. The urinary excretion of cotinine was normally distributed over a 2h period (logarithmically transformed). Individuals with urinary cotinine levels in the ranges of 0.01-0.21, and 0.52-94.99μg/2h were categorized as poor metabolizes (PMs: 6.5%), and extensive metabolizers (EMs: 93.5%), respectively. The majority of EMs (45%) carried homozygous wild-type genotypes (CYP2A6*1A/*1A, CYP2A6*1A/*1B and CYP2A6*1B/*1B), whereas only 1% of PMs carried these genotypes. Markedly higher frequencies of EMs were also observed in all heterozygous defective genotypes including the null genotype (*4C/*4C; 1 subject). A weak but significant positive correlation was observed between total amounts of urinary cadmium excretion and total cotinine excretion over 2h. Our study shows generally good agreement between CYP2A6 genotypes and phenotypes. Smokers accumulated about 3-4-fold higher mean total amounts of 2-h urinary cadmium excretion (127.5±218.2ng/2h) than that of non-smokers (40.5±78.4ng/2h). Among the smokers (n=16), homologous wild-type genotype *1/*1 was significantly the predominant genotype (6/16) compared with other defective allele including *4C/*4C. In addition, 2h urinary excretion of cotinine in smokers of all genotypes was significantly higher than non-smokers. The proportion of smokers who smoked more than 5 cigarettes/day was significantly higher in EMs in all CYP2A6 genotypes (n=14) than in PMs (n=0).
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Affiliation(s)
- Roongnapa Apinan
- Pharmacology and Toxicology Unit, Graduate Program in Biomedical Sciences, Thammasat University, Thailand
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Zhou SF, Liu JP, Chowbay B. Polymorphism of human cytochrome P450 enzymes and its clinical impact. Drug Metab Rev 2009; 41:89-295. [PMID: 19514967 DOI: 10.1080/03602530902843483] [Citation(s) in RCA: 502] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Pharmacogenetics is the study of how interindividual variations in the DNA sequence of specific genes affect drug response. This article highlights current pharmacogenetic knowledge on important human drug-metabolizing cytochrome P450s (CYPs) to understand the large interindividual variability in drug clearance and responses in clinical practice. The human CYP superfamily contains 57 functional genes and 58 pseudogenes, with members of the 1, 2, and 3 families playing an important role in the metabolism of therapeutic drugs, other xenobiotics, and some endogenous compounds. Polymorphisms in the CYP family may have had the most impact on the fate of therapeutic drugs. CYP2D6, 2C19, and 2C9 polymorphisms account for the most frequent variations in phase I metabolism of drugs, since almost 80% of drugs in use today are metabolized by these enzymes. Approximately 5-14% of Caucasians, 0-5% Africans, and 0-1% of Asians lack CYP2D6 activity, and these individuals are known as poor metabolizers. CYP2C9 is another clinically significant enzyme that demonstrates multiple genetic variants with a potentially functional impact on the efficacy and adverse effects of drugs that are mainly eliminated by this enzyme. Studies into the CYP2C9 polymorphism have highlighted the importance of the CYP2C9*2 and *3 alleles. Extensive polymorphism also occurs in other CYP genes, such as CYP1A1, 2A6, 2A13, 2C8, 3A4, and 3A5. Since several of these CYPs (e.g., CYP1A1 and 1A2) play a role in the bioactivation of many procarcinogens, polymorphisms of these enzymes may contribute to the variable susceptibility to carcinogenesis. The distribution of the common variant alleles of CYP genes varies among different ethnic populations. Pharmacogenetics has the potential to achieve optimal quality use of medicines, and to improve the efficacy and safety of both prospective and currently available drugs. Further studies are warranted to explore the gene-dose, gene-concentration, and gene-response relationships for these important drug-metabolizing CYPs.
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Affiliation(s)
- Shu-Feng Zhou
- School of Health Sciences, RMIT University, Bundoora, Victoria, Australia.
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Ponomarenko PM, Ponomarenko MP, Drachkova IA, Lysova MV, Arshinova TV, Savinkova LK, Kolchanov NA. Prediction of the affinity of the TATA-binding protein to TATA boxes with single nucleotide polymorphisms. Mol Biol 2009. [DOI: 10.1134/s0026893309030157] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Savinkova LK, Ponomarenko MP, Ponomarenko PM, Drachkova IA, Lysova MV, Arshinova TV, Kolchanov NA. TATA box polymorphisms in human gene promoters and associated hereditary pathologies. BIOCHEMISTRY (MOSCOW) 2009; 74:117-29. [PMID: 19267666 DOI: 10.1134/s0006297909020011] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
TATA-binding protein (TBP) is the first basal factor that recognizes and binds a TATA box on TATA-containing gene promoters transcribed by RNA polymerase II. Data available in the literature are indicative of admissible variability of the TATA box. The TATA box flanking sequences can influence TBP affinity as well as the level of basal and activated transcription. The possibility of mediated involvement in in vivo gene expression regulation of the TBP interactions with variant TATA boxes is supported by data on TATA box polymorphisms and associated human hereditary pathologies. A table containing data on TATA element polymorphisms in human gene promoters (about 40 mutations have been described), associated with particular pathologies, their short functional characteristics, and manifestation mechanisms of TATA-box SNPs is presented. Four classes of polymorphisms are considered: TATA box polymorphisms that weaken and enhance promoter, polymorphisms causing TATA box emergence and disappearance, and human virus TATA box polymorphisms. The described examples are indicative of the polymorphism-associated severe pathologies like thalassemia, the increased risk of hepatocellular carcinoma, sensitivity to H. pylori infection, oral cavity and lung cancers, arterial hypertension, etc.
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Affiliation(s)
- L K Savinkova
- Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia.
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Yusof W, Gan SH. High prevalence of CYP2A6⁎4 and CYP2A6⁎9 alleles detected among a Malaysian population. Clin Chim Acta 2009; 403:105-9. [DOI: 10.1016/j.cca.2009.01.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Revised: 01/28/2009] [Accepted: 01/28/2009] [Indexed: 10/21/2022]
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In vivo analysis of efavirenz metabolism in individuals with impaired CYP2A6 function. Pharmacogenet Genomics 2009; 19:300-9. [DOI: 10.1097/fpc.0b013e328328d577] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Wang HH, Liao YW, Chiang HL, Wu JY, Chen YT. Novel DNA sequence variations of cytochrome P450 genes in the Han Chinese population. Pharmacogenomics 2009; 10:359-74. [DOI: 10.2217/14622416.10.3.359] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aim: Cytochrome P450 is an important monooxygenase responsible for the metabolism of a large variety of structurally diverse compounds. The aim of this study was to systematically investigate the DNA sequence variations in 14 cytochrome P450 genes relevant to drug metabolism in the Han Chinese population. Materials & methods: We sequenced these 14 genes in 23 subjects and determined the allele frequencies. Results: We identified a total of 312 genetic variants, which included 80 (25.6%) novel variants. These novel variants included 67 noncoding variants, four synonymous and nine nonsynonymous variants. Among these variants, an 11-nucleotide insertion in the 3´-flanking site of intron 6 in CYP2E1 (c.968-77_-76insGATGGGTGGAT) had the highest allele frequency of 0.565. A total of 16 of these novel variants were predicted to have potential functional consequences; however, among them only c.-1299T>A in CYP2C18 and c.-498C>A in CYP2D6 reached a frequency of 4.9%. Conclusions: This study establishes a genetic database of cytochrome P450 genes in the Han Chinese population and suggests further genetic diversity throughout this important gene family.
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Affiliation(s)
- Hui-Hung Wang
- Institute of Biomedical Sciences, Academia Sinica, No 128, Sec. 2, Academia Road, Nankang, Taipei 11529, Taiwan
| | - Yie-Wen Liao
- Institute of Biomedical Sciences, Academia Sinica, No 128, Sec. 2, Academia Road, Nankang, Taipei 11529, Taiwan
| | - Hung-Lun Chiang
- Institute of Biomedical Sciences, Academia Sinica, No 128, Sec. 2, Academia Road, Nankang, Taipei 11529, Taiwan
| | - Jer-Yuarn Wu
- Institute of Biomedical Sciences, Academia Sinica, No 128, Sec. 2, Academia Road, Nankang, Taipei 11529, Taiwan
- China Medical College Hospital, Taiwan
| | - Yuan-Tsong Chen
- Institute of Biomedical Sciences, Academia Sinica, No 128, Sec. 2, Academia Road, Nankang, Taipei 11529, Taiwan
- Duke University Medical Center, NC, USA
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CYP2A6 genotypes and coumarin-oxidation phenotypes in a Thai population and their relationship to tobacco smoking. Eur J Clin Pharmacol 2008; 65:377-84. [DOI: 10.1007/s00228-008-0595-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2008] [Accepted: 11/18/2008] [Indexed: 10/21/2022]
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Rossini A, de Almeida Simão T, Albano RM, Pinto LFR. CYP2A6 polymorphisms and risk for tobacco-related cancers. Pharmacogenomics 2008; 9:1737-52. [PMID: 19018727 DOI: 10.2217/14622416.9.11.1737] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Tobacco consumption is the main identifiable risk to cancer, contributing to the majority of tumors in upper aerodigestive tissues. The psychoactive compound responsible for tobacco addiction, nicotine and the potent carcinogens present at high concentrations either in cigarette mainstream smoke or in smokeless tobacco products, 4-(methylnitrosamino)-1-(3-pyridyl)-butanone (NNK) and N-nitrosonornicotine (NNN) can be metabolized by CYP2A6. CYP2A6 is expressed in many aerodigestive tissues with high interindividual variability. The CYP2A6 gene is highly polymorphic and CYP2A6 alleles coding for enzymes with altered expression or metabolic capacity produce alterations in nicotine metabolism in vivo and seem to influence smoking behavior. These polymorphisms may change the rate of NNK and NNN activation and, therefore, may influence cancer risk associated with tobacco consumption. However, to date only a few and inconclusive studies have addressed the risk that a given CYP2A6 polymorphism presents for the development of tobacco-related tumors. Most, but not all, show a reduced risk associated with alleles that result in decreased enzyme activity. The overlapping substrate specificity and tissue expression between CYP2A6 and the highly similar CYP2A13 may add to the conflicting results observed. The intricate regulation of CYP2A6 and the variation of structurally different chemical compounds capable of inhibiting CYP2A enzymes also add to the complexity. Finally, the interaction between polymorphisms of genes that code for CYP2A6, CYP2A13 and other potent carcinogen-metabolizing CYP enzymes may help to determine individuals that are at higher risk of developing tumors associated with tobacco consumption.
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Affiliation(s)
- Ana Rossini
- Universidade do Estado do Rio de Janeiro, Instituto de Biologia Roberto Alcântara Gomes, Departamento de Bioquímica Brazil, Rio de Janeiro, Brazil
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