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Twesigomwe D, Drögemöller BI, Wright GEB, Adebamowo C, Agongo G, Boua PR, Matshaba M, Paximadis M, Ramsay M, Simo G, Simuunza MC, Tiemessen CT, Lombard Z, Hazelhurst S. Characterization of CYP2B6 and CYP2A6 Pharmacogenetic Variation in Sub-Saharan African Populations. Clin Pharmacol Ther 2024; 115:576-594. [PMID: 38049200 DOI: 10.1002/cpt.3124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 11/16/2023] [Indexed: 12/06/2023]
Abstract
Genetic variation in CYP2B6 and CYP2A6 is known to impact interindividual response to antiretrovirals, nicotine, and bupropion, among other drugs. However, the full catalogue of clinically relevant pharmacogenetic variants in these genes is yet to be established, especially across African populations. This study therefore aimed to characterize the star allele (haplotype) distribution in CYP2B6 and CYP2A6 across diverse and understudied sub-Saharan African (SSA) populations. We called star alleles from 961 high-depth full genomes using StellarPGx, Aldy, and PyPGx. In addition, we performed CYP2B6 and CYP2A6 star allele frequency comparisons between SSA and other global biogeographical groups represented in the new 1000 Genomes Project high-coverage dataset (n = 2,000). This study presents frequency information for star alleles in CYP2B6 (e.g., *6 and *18; frequency of 21-47% and 2-19%, respectively) and CYP2A6 (e.g., *4, *9, and *17; frequency of 0-6%, 3-10%, and 6-20%, respectively), and predicted phenotypes (for CYP2B6), across various African populations. In addition, 50 potentially novel African-ancestry star alleles were computationally predicted by StellarPGx in CYP2B6 and CYP2A6 combined. For each of these genes, over 4% of the study participants had predicted novel star alleles. Three novel star alleles in CYP2A6 (*54, *55, and *56) and CYP2B6 apiece, and several suballeles were further validated via targeted Single-Molecule Real-Time resequencing. Our findings are important for informing the design of comprehensive pharmacogenetic testing platforms, and are highly relevant for personalized medicine strategies, especially relating to antiretroviral medication and smoking cessation treatment in Africa and the African diaspora. More broadly, this study highlights the importance of sampling diverse African ethnolinguistic groups for accurate characterization of the pharmacogene variation landscape across the continent.
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Affiliation(s)
- David Twesigomwe
- Sydney Brenner Institute for Molecular Bioscience, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Division of Human Genetics, National Health Laboratory Service, and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Britt I Drögemöller
- Department of Biochemistry and Medical Genetics, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Galen E B Wright
- Neuroscience Research Program, Kleysen Institute for Advanced Medicine, Winnipeg Health Sciences Centre and Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
- Department of Pharmacology and Therapeutics, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Clement Adebamowo
- Institute for Human Virology, Abuja, Nigeria
- Division of Cancer Epidemiology, Department of Epidemiology and Public Health, and the Marlene and Stewart Greenebaum Comprehensive Cancer Centre, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Godfred Agongo
- Navrongo Health Research Centre, Ghana Health Service, Navrongo, Ghana
- Department of Biochemistry and Forensic Sciences, School of Chemical and Biochemical Sciences, C.K. Tedam University of Technology and Applied Sciences, Navrongo, Ghana
| | - Palwendé R Boua
- Sydney Brenner Institute for Molecular Bioscience, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Clinical Research Unit of Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Mogomotsi Matshaba
- Botswana-Baylor Children's Clinical Centre of Excellence, Gaborone, Botswana
- Retrovirology, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Maria Paximadis
- Centre for HIV and STIs, National Institute for Communicable Diseases, National Health Laboratory Services and Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, South Africa
| | - Michèle Ramsay
- Sydney Brenner Institute for Molecular Bioscience, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Division of Human Genetics, National Health Laboratory Service, and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Gustave Simo
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Martin C Simuunza
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, Lusaka, Zambia
| | - Caroline T Tiemessen
- Centre for HIV and STIs, National Institute for Communicable Diseases, National Health Laboratory Services and Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Zané Lombard
- Division of Human Genetics, National Health Laboratory Service, and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Scott Hazelhurst
- Sydney Brenner Institute for Molecular Bioscience, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- School of Electrical and Information Engineering, University of the Witwatersrand, Johannesburg, South Africa
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2
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Langlois AWR, El-Boraie A, Pouget JG, Cox LS, Ahluwalia JS, Fukunaga K, Mushiroda T, Knight J, Chenoweth MJ, Tyndale RF. Genotyping, characterization, and imputation of known and novel CYP2A6 structural variants using SNP array data. J Hum Genet 2023:10.1038/s10038-023-01148-y. [PMID: 37059825 DOI: 10.1038/s10038-023-01148-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 03/23/2023] [Accepted: 03/30/2023] [Indexed: 04/16/2023]
Abstract
CYP2A6 metabolically inactivates nicotine. Faster CYP2A6 activity is associated with heavier smoking and higher lung cancer risk. The CYP2A6 gene is polymorphic, including functional structural variants (SV) such as gene deletions (CYP2A6*4), duplications (CYP2A6*1 × 2), and hybrids with the CYP2A7 pseudogene (CYP2A6*12, CYP2A6*34). SVs are challenging to genotype due to their complex genetic architecture. Our aims were to develop a reliable protocol for SV genotyping, functionally phenotype known and novel SVs, and investigate the feasibility of CYP2A6 SV imputation from SNP array data in two ancestry populations. European- (EUR; n = 935) and African- (AFR; n = 964) ancestry individuals from smoking cessation trials were genotyped for SNPs using an Illumina array and for CYP2A6 SVs using Taqman copy number (CN) assays. SV-specific PCR amplification and Sanger sequencing was used to characterize a novel SV. Individuals with SVs were phenotyped using the nicotine metabolite ratio, a biomarker of CYP2A6 activity. SV diplotype and SNP array data were integrated and phased to generate ancestry-specific SV reference panels. Leave-one-out cross-validation was used to investigate the feasibility of CYP2A6 SV imputation. A minimal protocol requiring three Taqman CN assays for CYP2A6 SV genotyping was developed and known SV associations with activity were replicated. The first domain swap CYP2A6-CYP2A7 hybrid SV, CYP2A6*53, was identified, sequenced, and associated with lower CYP2A6 activity. In both EURs and AFRs, most SV alleles were identified using imputation (>70% and >60%, respectively); importantly, false positive rates were <1%. These results confirm that CYP2A6 SV imputation can identify most SV alleles, including a novel SV.
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Affiliation(s)
- Alec W R Langlois
- Department of Pharmacology and Toxicology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 100 Stokes Street, Toronto, ON, M6J 1H4, Canada
| | - Ahmed El-Boraie
- Department of Pharmacology and Toxicology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 100 Stokes Street, Toronto, ON, M6J 1H4, Canada
| | - Jennie G Pouget
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 100 Stokes Street, Toronto, ON, M6J 1H4, Canada
- Department of Psychiatry, University of Toronto, 250 College Street, Toronto, ON, M5T 1R8, Canada
| | - Lisa Sanderson Cox
- Department of Population Health, University of Kansas School of Medicine, Kansas City, KS, 66160, USA
| | - Jasjit S Ahluwalia
- Departments of Behavioral and Social Sciences and Medicine, Brown University School of Public Health, Providence, RI, 02912, USA
| | - Koya Fukunaga
- Center for Integrative Medical Sciences, RIKEN, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Taisei Mushiroda
- Center for Integrative Medical Sciences, RIKEN, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Jo Knight
- Data Science Institute and Medical School, Lancaster University, Lancaster, UK
| | - Meghan J Chenoweth
- Department of Pharmacology and Toxicology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 100 Stokes Street, Toronto, ON, M6J 1H4, Canada
- Department of Psychiatry, University of Toronto, 250 College Street, Toronto, ON, M5T 1R8, Canada
| | - Rachel F Tyndale
- Department of Pharmacology and Toxicology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 100 Stokes Street, Toronto, ON, M6J 1H4, Canada.
- Department of Psychiatry, University of Toronto, 250 College Street, Toronto, ON, M5T 1R8, Canada.
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3
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Li J, Hussain Z, Zhu J, Lei S, Lu J, Ma X. Role of CYP2A6 in Methimazole Bioactivation and Hepatotoxicity. Chem Res Toxicol 2021; 34:2534-2539. [PMID: 34788025 DOI: 10.1021/acs.chemrestox.1c00300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Methimazole (MMI) is a widely used antithyroid drug, but it can cause hepatotoxicity by unknown mechanisms. Previous studies showed that the hepatic metabolism of MMI produces N-methylthiourea, leading to liver damage. However, the specific enzyme responsible for the production of the toxic metabolite N-methylthiourea is still unclear. In this study, we screened cytochromes P450 (CYPs) in N-methylthiourea production from MMI. CYP2A6 was identified as the key enzyme in catalyzing MMI metabolism to produce N-methylthiourea. When mice were pretreated with a CYP2A6 inhibitor, formation of N-methylthiourea from MMI was remarkably reduced. Consistently, the CYP2A6 inhibitor prevented MMI-induced hepatotoxicity. These results demonstrated that CYP2A6 is essential in MMI bioactivation and hepatotoxicity.
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Affiliation(s)
- Jianhua Li
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Zahir Hussain
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Junjie Zhu
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Saifei Lei
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Jie Lu
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Xiaochao Ma
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
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Nikkholgh A, Ahmad Ebrahimi S, Bakhshi E, Zarrindast MR, Asgari Y, Torkaman-Boutorabi A. New Biomarkers Based on Smoking-Related Phenotypes for Smoking Cessation Outcomes of Nicotine Replacement Therapy: A Prospective Study. Basic Clin Neurosci 2021; 12:639-650. [PMID: 35173918 PMCID: PMC8818114 DOI: 10.32598/bcn.2021.1552.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 06/02/2021] [Accepted: 08/28/2021] [Indexed: 11/21/2022] Open
Abstract
Introduction: Identifying a potent biomarker for smoking cessation can play a key role in predicting prognosis and improving treatment outcomes. This study aimed to evaluate the contribution of new biomarkers based on the levels of Cotinine (Cot) and carbon monoxide (CO) to the short- and long-term quit rates of nicotine replacement therapies (Nicotine Patch [NP] and Nicotine Lozenge [NL]). Methods: In this prospective interventional study, 124 smokers under treatment with the 5A’s method were selected from an outpatient smoking cessation center in district 18 of Tehran City, Iran. The study was conducted from April 2016 to December 2018. They were divided into NP (n=56) and NL (n=61) intervention groups. The levels of Cot and CO were measured using ELISA and breath analysis at the beginning of the study. Three markers were calculated: Cot/CO, Cot to cigarette per day ratio (Cot/CPD), and CO/CPD. Binary logistic regression models and generalized estimating equations models were analyzed by SPSS software, version 21 to determine the chances of quitting smoking. Results: Of the NP participants, 30.4% and 19.6% were abstinent after 2 and 6 months, respectively, while NL was found less effective with 19.7% for 2-month follow-up and 13.1% for 6-month follow-up. The 6-month success of quitting attempts was significantly different for the NP participants at the second half of Cot/CO (P=0.029). Of the NL participants, CO/CPD would be a superior predictor for smoking cessation success (P>0.05). Conclusion: The findings of this study suggested two markers of Cot/CO and CO/CPD in this order for the optimum treatment outcomes of NP and NL.
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Affiliation(s)
- Arash Nikkholgh
- Department of Neuroscience and Addiction Studies, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Soltan Ahmad Ebrahimi
- Department of Pharmacology, School of Medicine, Iran University of Medical Sciences, Tehran Iran
| | - Enayatollah Bakhshi
- Department of Biostatistics and Epidemiology, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Mohammad-Reza Zarrindast
- Iranian National Center for Addiction Studies, Tehran University of Medical Sciences, Tehran, Iran.,Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Yazdan Asgari
- Department of Medical Biotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Anahita Torkaman-Boutorabi
- Department of Neuroscience and Addiction Studies, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran.,Research Center for Cognitive and Behavioral Studies, Tehran University of Medical Sciences, Tehran, Iran
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5
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Goyal N, Sridhar J, Do C, Bratton M, Shaik S, Jiang Q, Foroozesh M. Identification of CYP 2A6 inhibitors in an effort to mitigate the harmful effects of the phytochemical nicotine. JOURNAL OF CANCER METASTASIS AND TREATMENT 2021; 7:18. [PMID: 34722929 PMCID: PMC8555909 DOI: 10.20517/2394-4722.2020.143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
AIM In this study, our goal was to study the inhibition of nicotine metabolism by P450 2A6, as a means for reduction in tobacco use and consequently the prevention of smoking-related cancers. Nicotine, a phytochemical, is an addictive stimulant, responsible for the tobacco-dependence in smokers. Many of the other phytochemicals in tobacco, including polycyclic aromatic hydrocarbons, N-nitrosamines, and aromatic amines, are potent systemic carcinogens. Tobacco smoking causes about one of every five deaths in the United States annually. Nicotine plasma concentration is maintained by the smokers' smoking behavior within a small range. Nicotine is metabolized by cytochrome P450s 2A6 and 2A13 to cotinine. This metabolism causes a decrease in nicotine plasma levels, which in turn leads to increased tobacco smoking, and increased exposure to the tobacco carcinogens. METHODS Using the phytochemical nicotine as a lead structure, and taking its interactions with the P450 2A6 binding pocket into consideration, new pyridine derivatives were designed and synthesized as potential selective mechanism-based inhibitors for this enzyme. RESULTS The design and synthesis of two series of novel pyridine-based compounds, with varying substituents and substitution locations on the pyridine ring, as well as their inhibitory activities on cytochrome P450 2A6 and their interactions with its active site are discussed here. Substitutions at position 3 of the pyridine ring with an imidazole or propargyl ether containing group showed the most optimal interactions with the P4502A6 active site. CONCLUSION The pyridine compounds with an imidazole or propargyl ether containing substituent on position 3 were found to be promising lead compounds for further development. Hydrogen-bonding interactions were determined to be crucial for effective binding of these molecules within the P450 2A6 active site.
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Affiliation(s)
- Navneet Goyal
- Department of Chemistry, Xavier University of Louisiana, New Orleans, LA 70125, USA
| | - Jayalakshmi Sridhar
- Department of Chemistry, Xavier University of Louisiana, New Orleans, LA 70125, USA
| | - Camilla Do
- Department of Chemistry, Xavier University of Louisiana, New Orleans, LA 70125, USA
| | - Melyssa Bratton
- Cell and Molecular Biology and Bioinformatic Core, College of Pharmacy, Xavier University of Louisiana, New Orleans, LA 70125, USA
| | - Shahensha Shaik
- Cell and Molecular Biology and Bioinformatic Core, College of Pharmacy, Xavier University of Louisiana, New Orleans, LA 70125, USA
| | - Quan Jiang
- Cell and Molecular Biology and Bioinformatic Core, College of Pharmacy, Xavier University of Louisiana, New Orleans, LA 70125, USA
| | - Maryam Foroozesh
- Department of Chemistry, Xavier University of Louisiana, New Orleans, LA 70125, USA
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Wong AL, McElroy SM, Robinson JM, Mulloy SM, El Banna FK, Harris AC, LeSage MG, Lee AM. Flavor-specific enhancement of electronic cigarette liquid consumption and preference in mice. Drug Alcohol Depend 2020; 211:107995. [PMID: 32354580 PMCID: PMC7328293 DOI: 10.1016/j.drugalcdep.2020.107995] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 03/24/2020] [Accepted: 03/25/2020] [Indexed: 12/22/2022]
Abstract
BACKGROUND The use of electronic cigarettes has increased over the past decade. To determine how the abuse liability of electronic cigarette liquids (e-liquids) differs from nicotine alone, and to determine the impact of flavor, we compared nicotine-containing fruit- and tobacco-flavored e-liquids, and their nicotine-free versions, to nicotine alone in mouse models of oral consumption, reward and aversion. METHODS Adult male C57BL/6 J mice voluntarily consumed oral nicotine, equivalent nicotine concentrations of fruit- and tobacco-flavored e-liquid, and equivalent dilutions of the nicotine-free versions in 2-bottle choice tests. Conditioned place preference and place aversion were assessed with peripherally administered e-liquids or nicotine. Serum nicotine and cotinine levels were measured after subcutaneous injections of e-liquid or nicotine. RESULTS Mice showed higher consumption and preference for the fruit-flavored e-liquid compared with nicotine alone. This increase was not due to the flavor itself as consumption of the nicotine-free fruit-flavored e-liquid was not elevated until the highest concentration tested. The increased consumption and preference were not observed with the tobacco-flavored e-liquid. The conditioned place preference, place aversion and nicotine pharmacokinetics of the fruit-flavored e-liquid were not significantly different from nicotine alone. CONCLUSIONS Our data suggest that fruit, but not tobacco flavor, increased the oral consumption of e-liquid compared with nicotine alone. Moreover, this enhancement was not due to increased consumption of the flavor itself, altered rewarding or aversive properties after peripheral administration, or altered pharmacokinetics. This flavor-specific enhancement suggests that some flavors may lead to higher nicotine intake and increased use of e-liquids compared with nicotine alone.
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Affiliation(s)
- A L Wong
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, USA
| | - S M McElroy
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, USA
| | - J M Robinson
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, USA
| | - S M Mulloy
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN, USA
| | - F K El Banna
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, USA
| | - A C Harris
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN, USA; Department of Medicine, University of Minnesota, Minneapolis, MN, USA; Department of Medicine, Hennepin Healthcare Research Institute, Minneapolis, MN, USA; Department of Psychology, University of Minnesota, Minneapolis, MN, USA
| | - M G LeSage
- Department of Medicine, University of Minnesota, Minneapolis, MN, USA; Department of Medicine, Hennepin Healthcare Research Institute, Minneapolis, MN, USA; Department of Psychology, University of Minnesota, Minneapolis, MN, USA
| | - A M Lee
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, USA; Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN, USA.
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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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Abstract
Substance and alcohol use disorders impose large health and economic burdens on individuals, families, communities, and society. Neither prevention nor treatment efforts are effective in all individuals. Results are often modest. Advances in neuroscience and addiction research have helped to describe the neurobiological changes that occur when a person transitions from recreational substance use to a substance use disorder or addiction. Understanding both the drivers and consequences of substance use in vulnerable populations, including those whose brains are still maturing, has revealed behavioral and biological characteristics that can increase risks of addiction. These findings are particularly timely, as law- and policymakers are tasked to reverse the ongoing opioid epidemic, as more states legalize marijuana, as new products including electronic cigarettes and newly designed abused substances enter the legal and illegal markets, and as "deaths of despair" from alcohol and drug misuse continue.
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Affiliation(s)
- George R. Uhl
- New Mexico VA Healthcare SystemAlbuquerqueNew Mexico
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Schwarz UI, Gulilat M, Kim RB. The Role of Next-Generation Sequencing in Pharmacogenetics and Pharmacogenomics. Cold Spring Harb Perspect Med 2019; 9:cshperspect.a033027. [PMID: 29844222 DOI: 10.1101/cshperspect.a033027] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Inherited genetic variations in pharmacogenetic loci are widely acknowledged as important determinants of phenotypic differences in drug response, and may be actionable in the clinic. However, recent studies suggest that a considerable number of novel rare variants in pharmacogenes likely contribute to a still unexplained fraction of the observed interindividual variability. Next-generation sequencing (NGS) represents a rapid, relatively inexpensive, large-scale DNA sequencing technology with potential relevance as a comprehensive pharmacogenetic genotyping platform to identify genetic variation related to drug therapy. However, many obstacles remain before the clinical use of NGS-based test results, including technical challenges, functional interpretation, and strict requirements for diagnostic tests. Advanced computational analyses, high-throughput screening methodologies, and generation of shared resources with cell-based and clinical information will facilitate the integration of NGS data into candidate genotyping approaches, likely enhancing future drug phenotype predictions in patients.
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Affiliation(s)
- Ute I Schwarz
- Division of Clinical Pharmacology, Department of Medicine, Western University, London, Ontario N6A 5A5, Canada.,Department of Physiology and Pharmacology, Western University, London, Ontario N6A 5A5, Canada
| | - Markus Gulilat
- Department of Physiology and Pharmacology, Western University, London, Ontario N6A 5A5, Canada
| | - Richard B Kim
- Division of Clinical Pharmacology, Department of Medicine, Western University, London, Ontario N6A 5A5, Canada.,Department of Physiology and Pharmacology, Western University, London, Ontario N6A 5A5, Canada
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Taghavi T, Arger CA, Heil SH, Higgins ST, Tyndale RF. Cigarette consumption and biomarkers of nicotine exposure during pregnancy and postpartum. Addiction 2018; 113:2087-2096. [PMID: 29920836 PMCID: PMC6175668 DOI: 10.1111/add.14367] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 04/05/2018] [Accepted: 06/11/2018] [Indexed: 01/29/2023]
Abstract
BACKGROUND AND AIMS Smokers can regulate their nicotine intake by altering the number of cigarettes smoked per day (CPD) and their smoking intensity. The current study aimed to compare the utility of self-reported CPD, total nicotine equivalents (TNE) and urinary cotinine to estimate nicotine intake during pregnancy. DESIGN Longitudinal smoking behavior and biomarker data were collected at early pregnancy, late pregnancy and at postpartum as part of a smoking cessation trial to examine voucher-based incentives for decreasing smoking. SETTING Obstetric practices in Burlington, Vermont, United States. PARTICIPANTS A subset of participants (n = 47) from the parent trial, recruited between December 2006 and June 2012, who provided a urine sample at each assessment during early pregnancy, late pregnancy and postpartum. MEASUREMENTS Smoking was assessed using self-reported CPD, TNE, TNE/CPD and urinary cotinine. FINDINGS Pregnant smokers reported smoking 10.4 CPD at early pregnancy, 7.2 CPD at late pregnancy (a 31% reduction at late pregnancy, P = 0.001) and 8.6 CPD at postpartum (a 19% increase from late pregnancy, P = 0.08). TNE exposure was 41% (P = 0.07) and 48% (P = 0.03) lower at early and late pregnancy, respectively, compared to postpartum. TNE/CPD was on average 167% higher at late pregnancy compared to early pregnancy (P = 0.01) and remained high at postpartum, where it was 111% higher compared to early pregnancy (P = 0.007). Uriniary cotinine underestimated nicotine intake by 55% during early pregnancy and by 65% during late pregnancy compared to postpartum (Pinteraction < 0.001); the underestimation was greater in slower (Pinteraction < 0.001) versus faster (Pinteraction = 0.04) nicotine metabolizers. CONCLUSIONS Neither cigarettes smoked per day (CPD) nor cotinine provides an accurate estimate of nicotine exposure during pregnancy. CPD underestimates nicotine intake substantially due to under-reporting and/or higher intensity of smoking, while cotinine underestimates nicotine intake markedly due to accelerated nicotine (and cotinine) metabolism during pregnancy.
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Affiliation(s)
- Taraneh Taghavi
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Christopher A. Arger
- University of Vermont Center on Tobacco Regulatory Science, Burlington, VT, USA; Department of Psychiatry, University of Vermont, Burlington, VT, USA,Department of Psychological Science, University of Vermont, Burlington, VT, USA
| | - Sarah H. Heil
- University of Vermont Center on Tobacco Regulatory Science, Burlington, VT, USA; Department of Psychiatry, University of Vermont, Burlington, VT, USA,Department of Psychological Science, University of Vermont, Burlington, VT, USA
| | - Stephen T. Higgins
- University of Vermont Center on Tobacco Regulatory Science, Burlington, VT, USA; Department of Psychiatry, University of Vermont, Burlington, VT, USA,Department of Psychological Science, University of Vermont, Burlington, VT, USA
| | - Rachel F. Tyndale
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada,Department of Psychiatry, University of Toronto, Toronto, ON, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
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11
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Nicotine metabolite ratio predicts smoking topography: The Pennsylvania Adult Smoking Study. Drug Alcohol Depend 2018; 190:89-93. [PMID: 29990649 PMCID: PMC6348467 DOI: 10.1016/j.drugalcdep.2018.06.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 06/08/2018] [Accepted: 06/12/2018] [Indexed: 01/30/2023]
Abstract
BACKGROUND The nicotine metabolite ratio (NMR) as measured by the ratio of 3'hydroxycotinine to cotinine has been examined in relation to tobacco use patterns including cigarettes per day and quit success to determine its role in nicotine dependence. We examined the NMR in relation to smoking topography and tested the hypothesis that normal metabolizers have a greater total daily puff volume than slow metabolizers. METHODS The Pennsylvania Adult Smoking Study (PASS) is a longitudinal study of 352 adults who smoked, on average, 17 cigarettes per day. Subjects used a portable smoking topography device over a two-day period at home and at work. We measured the ratio of 3'hydroxycotinine to cotinine in the saliva of the subjects. RESULTS In multiple linear regression analyses, a higher rate of nicotine metabolism was significantly associated with increased daily puffs and total daily puff volume. In a mediation analysis, a significant, indirect effect of race on the relationship between NMR and puff volume was observed, with 22% of the effect mediated by white race. A higher NMR was also associated with female gender, white race, cigarettes per day and nicotine dependence measures. CONCLUSION The NMR was associated with tobacco use patterns including smoking topography. Faster nicotine metabolism was associated with greater total daily puffs and puff volume.
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Bozinoff N, Le Foll B. Understanding the implications of the biobehavioral basis of nicotine addiction and its impact on the efficacy of treatment. Expert Rev Respir Med 2018; 12:793-804. [PMID: 30092681 DOI: 10.1080/17476348.2018.1507736] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Tobacco use remains the leading cause of preventable death in the United States. There are efficacious behavioral and pharmacological options for smoking cessation including three FDA approved therapies - nicotine replacement therapy, varenicline and bupropion. Nevertheless, uptake of smoking cessation treatments continues to be poor and there is a need for novel smoking cessation treatments. Areas covered: This article reviews the biobehavioral basis of nicotine addiction, its implications for smoking cessation treatments, the various neurotransmitter systems involved in nicotine addictive effects, and their potential therapeutic value. Included are discussions around the role of genetic factors in predicting response to pharmacotherapy and what we know about appropriate application of pharmacotherapy and behavioral interventions for tobacco use disorder. The evidence for harm reduction measures in individuals who are not willing or able to quit smoking is also reviewed. Expert commentary: Many neurotransmitter system targets have been investigated as a result of our understanding of the underlying neurobiology of tobacco use disorder, and there remain important targets that have yet to be fully explored. rTMS or combination therapies are proposed as possible novel strategies to improve smoking cessation.
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Affiliation(s)
- Nikki Bozinoff
- a Department of Family and Community Medicine , University of Toronto , Toronto , Canada.,b Addiction Medicine Service, Acute Care Program , Centre for Addiction and Mental Health , Toronto , Canada
| | - Bernard Le Foll
- a Department of Family and Community Medicine , University of Toronto , Toronto , Canada.,b Addiction Medicine Service, Acute Care Program , Centre for Addiction and Mental Health , Toronto , Canada.,c Department of Pharmacology and Toxicology, Psychiatry, Institute of Medical Sciences , University of Toronto , Toronto , Canada.,d Centre for Addiction and Mental Health , Campbell Family Mental Health Research Institute, CAMH , Toronto , Canada.,e Translational Addiction Research Laboratory, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health , Toronto , Canada
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13
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Denton TT, Srivastava P, Xia Z, Chen G, Watson CJW, Wynd A, Lazarus P. Identification of the 4-Position of 3-Alkynyl and 3-Heteroaromatic Substituted Pyridine Methanamines as a Key Modification Site Eliciting Increased Potency and Enhanced Selectivity for Cytochrome P-450 2A6 Inhibition. J Med Chem 2018; 61:7065-7086. [PMID: 29995408 DOI: 10.1021/acs.jmedchem.8b00084] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cigarette smoking causes nearly one in every five deaths in the United States. The development of a specific inhibitor of cytochrome P450 2A6 (CYP2A6), the major nicotine-metabolizing enzyme in humans, which could be prescribed for the cessation of cigarette smoking, has been undertaken. To further refine the structure activity relationship of CYP2A6, previously synthesized 3-alkynyl and 3-heteroaromatic substituted pyridine methanamines were used as lead compounds. Isosteric pyridine replacement and appendage of all available positions around the pyridine ring with a methyl group was performed to identify a modification that would increase CYP2A6 inhibition potency, which led to 4g (IC50 = 0.055 mM) as a primary analogue. Potent compounds were evaluated for CYP selectivity, human liver microsomal half-life, and compliance with the rules of five. Top compounds (i.e., 6i, IC50 = 0.017 mM, >120 min half-life) are poised for further development as treatments for smoking and tobacco use cessation.
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Affiliation(s)
- Travis T Denton
- Department of Pharmaceutical Sciences , College of Pharmacy, Washington State University , Spokane , Washington 99202 , United States
| | - Pramod Srivastava
- Department of Pharmaceutical Sciences , College of Pharmacy, Washington State University , Spokane , Washington 99202 , United States
| | - Zuping Xia
- Department of Pharmaceutical Sciences , College of Pharmacy, Washington State University , Spokane , Washington 99202 , United States
| | - Gang Chen
- Department of Pharmaceutical Sciences , College of Pharmacy, Washington State University , Spokane , Washington 99202 , United States
| | - Christy J W Watson
- Department of Pharmaceutical Sciences , College of Pharmacy, Washington State University , Spokane , Washington 99202 , United States
| | - Alec Wynd
- Department of Pharmaceutical Sciences , College of Pharmacy, Washington State University , Spokane , Washington 99202 , United States
| | - Philip Lazarus
- Department of Pharmaceutical Sciences , College of Pharmacy, Washington State University , Spokane , Washington 99202 , United States
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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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Canova C, Richiardi L, Merletti F, Pentenero M, Gervasio C, Tanturri G, Garzino-Demo P, Pecorari G, Talamini R, Barzan L, Sulfaro S, Franchini G, Muzzolini C, Bordin S, Pugliese GN, Macrì E, Simonato L. Alcohol, Tobacco and Genetic Susceptibility in Relation to Cancers of the Upper Aerodigestive Tract in Northern Italy. TUMORI JOURNAL 2018; 96:1-10. [DOI: 10.1177/030089161009600101] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Aims and background Each year in Italy there are approximately 14,000 new cases and 7,000 deaths from cancer of the upper aerodigestive tract, which includes malignant tumors originating from the oral cavity, pharynx, larynx and esophagus. Established etiological factors include tobacco consumption and heavy alcohol drinking. The study of single nucleotide polymorphisms in upper aerodigestive tract cancer etiology may help to identify high-risk subgroups and to better understand the pathways leading to the development of these cancers. Methods Italian results on about 500 cases and 500 controls from a large case-control study (ARCAGE) conducted in 10 European countries are presented with the major objectives of updating results on the effects of alcohol and tobacco consumptions in northern Italy, investigating the role of genetic variation with regard to the metabolism of alcohol and carcinogens from tobacco smoke, and evaluating possible interactions of these single nucleotide polymorphisms with these carcinogens. Results The present study confirmed the importance of tobacco smoking and alcohol drinking as the main risk factors for upper aerodigestive tract cancers, indicating that about 68% of cancers among populations in northern Italy can be attributed to the combination of these risk factors. Significant associations between metabolizing phase I genes (CYP1A1 and CYP2A6), phase II genes (GSTA2) and upper aerodigestive tract cancers were found. A polymorphism of ADH1C has been associated with an increased risk of upper aerodigestive tract cancers, suggesting that the less rapid alcohol metabolizers are more susceptible to upper aerodigestive tract cancer risk. Conclusions Our results suggest that the ADH1C allele modifies the carcinogenic dose response for alcohol in the upper aerodigestive tract, giving rise to a gene-environment interaction. The role of genes as possible modifiers of life-style risks seems the most reliable.
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Affiliation(s)
- Cristina Canova
- Department of Environmental Medicine and Public Health, University of Padua, Padua
| | | | - Franco Merletti
- Unit of Cancer Epidemiology, CeRMS and University of Turin, Turin
| | | | | | | | | | | | - Renato Talamini
- Unit of Epidemiology and Biostatistics, Centro di Riferimento Oncologico, IRCCS, Aviano
| | - Luigi Barzan
- Head and Neck Unit, Pordenone General Hospital, Pordenone
| | | | - Giovanni Franchini
- Radiation Oncology Division, Centro di Riferimento Oncologico, IRCCS, Aviano
| | - Chiara Muzzolini
- Department of Environmental Medicine and Public Health, University of Padua, Padua
| | - Sandro Bordin
- Head and Neck Unit, SS Giovanni e Paolo Venice Hospital, Venice
| | | | - Ettore Macrì
- Department of Pathology, S. Martino Hospital, Belluno, Italy
| | - Lorenzo Simonato
- Department of Environmental Medicine and Public Health, University of Padua, Padua
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17
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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: 81] [Impact Index Per Article: 11.6] [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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18
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Tsuji M, Kanda H, Hayakawa T, Mori Y, Ito T, Hidaka T, Kakamu T, Kumagai T, Osaki Y, Kawazoe M, Sato S, Fukushima T. Nicotine cut-off value in human hair as a tool to distinguish active from passive smokers: A cross-sectional study in Japanese men. Cancer Biomark 2017; 20:41-48. [PMID: 28759953 DOI: 10.3233/cbm-170004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Nicotine concentration in hair is a useful marker of tobacco exposure. Detection of nicotine in the hair of non-smokers indicates passive smoking. Accurate measurement of nicotine among active and passive smokers can help in smoking cessation programs or programs designed to prevent secondhand smoke exposure. OBJECTIVE To establish, using high-performance liquid chromatography-ultraviolet detection (HPLC/UV), a hair nicotine cut-off value to distinguish active from passive smokers. METHODS Hair samples were collected from randomly chosen Japanese men (n= 192) between 2009 and 2011. Nicotine and cotinine levels in hair were measured using HPLC/UV with column-switching. T-tests and chi-square tests were performed to compare active and passive smokers, while receiver operating characteristic curves were used to evaluate the effectiveness of the cut-off value. RESULTS There were 69 active smokers and 123 passive smokers. The nicotine and cotinine concentrations in hair were significantly higher in active than in passive smokers (p< 0.01). The area under the curve for nicotine was 0.92. A hair nicotine cut-off value of 5.68 ng/mg, with a sensitivity of 94.2% and specificity of 87.0%, was identified as the optimal cut-off value for separating active from passive smokers. CONCLUSION Nicotine and cotinine concentrations in hair clearly distinguished active from passive smokers.
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Affiliation(s)
- Masayoshi Tsuji
- Department of Preventive Medicine & Public Health, Faculty of Medicine, Fukuoka University, Fukuoka 814-0180, Japan.,Department of Hygiene & Preventive Medicine, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Hideyuki Kanda
- Department of Hygiene & Preventive Medicine, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Takehito Hayakawa
- Department of Hygiene & Preventive Medicine, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Yayoi Mori
- Department of Hygiene & Preventive Medicine, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Teruna Ito
- Department of Hygiene & Preventive Medicine, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Tomoo Hidaka
- Department of Hygiene & Preventive Medicine, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Takeyasu Kakamu
- Department of Hygiene & Preventive Medicine, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Tomohiro Kumagai
- Department of Hygiene & Preventive Medicine, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Yoneatsu Osaki
- Department of Social Medicine, Faculty of Medicine, Tottori University, Yonago 683-8503, Japan
| | - Miki Kawazoe
- Department of Preventive Medicine & Public Health, Faculty of Medicine, Fukuoka University, Fukuoka 814-0180, Japan
| | - Sei Sato
- Department of Hygiene & Preventive Medicine, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Tetsuhito Fukushima
- Department of Hygiene & Preventive Medicine, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan
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19
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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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20
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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: 33] [Impact Index Per Article: 4.1] [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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21
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Amal Al Omari, Murry DJ. Pharmacogenetics of the Cytochrome P450 Enzyme System: Review of Current Knowledge and Clinical Significance. J Pharm Pract 2016. [DOI: 10.1177/0897190007304821] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Genetic variation in drug metabolizing enzymes is an important contributor to interindividual variation in drug disposition and response and is associated with significant clinical consequences. Many commonly used drugs are dependent on the cytochrome P450 monooxygenase enzymes (CYP450) for their metabolism and elimination. At present, more than 57 active human CYP450 genes are known, and the majority of these genes are polymorphic. Despite the large number of CYP450 genes, only the CYP1, CYP2, and CYP3 families of enzymes have a major role in drug metabolism. Approximately 10 CYP450s are responsible for the metabolism of a large number of pharmacologic agents in human beings. The polymorphic forms of the CYP450s are responsible for the development of a significant number of adverse drug reactions and may also contribute to drug response. Genetic polymorphisms have now been identified in the genes encoding all the main CYP450s that contribute to drug and other xenobiotic metabolism, and there are marked interethnic differences in the distribution and frequency of variant alleles. A review of the progress in the pharmacogenetics of P450s that are important for drug metabolism is presented with particular emphasis on the clinical relevance of this research.
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Affiliation(s)
- Amal Al Omari
- Department of Clinical and Administrative Pharmacy at the University of Iowa
| | - Daryl J. Murry
- Department of Clinical and Administrative Pharmacy, College of Pharmacy, S418 Phar, University of Iowa, 115 S. Grand Ave, Iowa City, IA 52242,
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22
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Lauschke VM, Ingelman-Sundberg M. Requirements for comprehensive pharmacogenetic genotyping platforms. Pharmacogenomics 2016; 17:917-24. [PMID: 27248710 DOI: 10.2217/pgs-2016-0023] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Recent research highlighted the large extent of rare variants in pharmacogenes and, on this basis, it was estimated that rare variants account for 30-40% of the functional variability in pharmacogenes. It has been proposed that comprehensive next-generation sequencing (NGS)-based sequencing of pharmacogenes could soon be a cost-effective methodology for clinical routine genotyping. Yet, multiple challenges on technical, interpretative and ethical levels need to be overcome to enable the reasonable dissemination of comprehensive pharmacogenetic genotyping, that includes rare genetic variation, into clinical practice. We argue that current pre-emptive pharmacogenetic testing cannot be based on comprehensive approaches but needs to be restricted to validated variants. Rather, comprehensive strategies should only be used for retrospective analyses of patients exhibiting unanticipated drug responses. Thereby, subsequent to computational analyses and functional validations, emerging variants with confirmed functional relevance can be incorporated into candidate genotyping strategies, thus refining and enhancing future pre-emptive genetic testing.
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Affiliation(s)
- Volker M Lauschke
- Section of Pharmacogenetics, Department of Physiology & Pharmacology, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | - Magnus Ingelman-Sundberg
- Section of Pharmacogenetics, Department of Physiology & Pharmacology, Karolinska Institutet, SE-17177 Stockholm, Sweden
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Chan J, Oshiro T, Thomas S, Higa A, Black S, Todorovic A, Elbarbry F, Harrelson JP. Inactivation of CYP2A6 by the Dietary Phenylpropanoid trans-Cinnamic Aldehyde (Cinnamaldehyde) and Estimation of Interactions with Nicotine and Letrozole. ACTA ACUST UNITED AC 2016; 44:534-43. [PMID: 26851241 DOI: 10.1124/dmd.115.067942] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 02/04/2016] [Indexed: 12/19/2022]
Abstract
Human exposure to trans-cinnamic aldehyde [t-CA; cinnamaldehyde; cinnamal; (E)-3-phenylprop-2-enal] is common through diet and through the use of cinnamon powder for diabetes and to provide flavor and scent in commercial products. We evaluated the likelihood of t-CA to influence metabolism by inhibition of P450 enzymes. IC50 values from recombinant enzymes indicated that an interaction is most probable for CYP2A6 (IC50 = 6.1 µM). t-CA was 10.5-fold more selective for human CYP2A6 than for CYP2E1; IC50 values for P450s 1A2, 2B6, 2C9, 2C19, 2D6, and 3A4 were 15.8-fold higher or more. t-CA is a type I ligand for CYP2A6 (KS = 14.9 µM). Inhibition of CYP2A6 by t-CA was metabolism-dependent; inhibition required NADPH and increased with time. Glutathione lessened the extent of inhibition modestly and statistically significantly. The carbon monoxide binding spectrum was dramatically diminished after exposure to NADPH and t-CA, suggesting degradation of the heme or CYP2A6 apoprotein. Using a static model and mechanism-based inhibition parameters (K(I) = 18.0 µM; k(inact) = 0.056 minute(-1)), changes in the area under the concentration-time curve (AUC) for nicotine and letrozole were predicted in the presence of t-CA (0.1 and 1 µM). The AUC fold-change ranged from 1.1 to 3.6. In summary, t-CA is a potential source of pharmacokinetic variability for CYP2A6 substrates due to metabolism-dependent inhibition, especially in scenarios when exposure to t-CA is elevated due to high dietary exposure, or when cinnamon is used as a treatment of specific disease states (e.g., diabetes).
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Affiliation(s)
- Jeannine Chan
- Chemistry Department, Pacific University Oregon, Forest Grove, Oregon (J.C., T.O., A.H., S.B.); and School of Pharmacy, Pacific University Oregon, Hillsboro, Oregon (S.T., A.H., S.B., A.T., F.E., J.P.H.)
| | - Tyler Oshiro
- Chemistry Department, Pacific University Oregon, Forest Grove, Oregon (J.C., T.O., A.H., S.B.); and School of Pharmacy, Pacific University Oregon, Hillsboro, Oregon (S.T., A.H., S.B., A.T., F.E., J.P.H.)
| | - Sarah Thomas
- Chemistry Department, Pacific University Oregon, Forest Grove, Oregon (J.C., T.O., A.H., S.B.); and School of Pharmacy, Pacific University Oregon, Hillsboro, Oregon (S.T., A.H., S.B., A.T., F.E., J.P.H.)
| | - Allyson Higa
- Chemistry Department, Pacific University Oregon, Forest Grove, Oregon (J.C., T.O., A.H., S.B.); and School of Pharmacy, Pacific University Oregon, Hillsboro, Oregon (S.T., A.H., S.B., A.T., F.E., J.P.H.)
| | - Stephen Black
- Chemistry Department, Pacific University Oregon, Forest Grove, Oregon (J.C., T.O., A.H., S.B.); and School of Pharmacy, Pacific University Oregon, Hillsboro, Oregon (S.T., A.H., S.B., A.T., F.E., J.P.H.)
| | - Aleksandar Todorovic
- Chemistry Department, Pacific University Oregon, Forest Grove, Oregon (J.C., T.O., A.H., S.B.); and School of Pharmacy, Pacific University Oregon, Hillsboro, Oregon (S.T., A.H., S.B., A.T., F.E., J.P.H.)
| | - Fawzy Elbarbry
- Chemistry Department, Pacific University Oregon, Forest Grove, Oregon (J.C., T.O., A.H., S.B.); and School of Pharmacy, Pacific University Oregon, Hillsboro, Oregon (S.T., A.H., S.B., A.T., F.E., J.P.H.)
| | - John P Harrelson
- Chemistry Department, Pacific University Oregon, Forest Grove, Oregon (J.C., T.O., A.H., S.B.); and School of Pharmacy, Pacific University Oregon, Hillsboro, Oregon (S.T., A.H., S.B., A.T., F.E., J.P.H.)
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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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Ito T, Tsuji M, Mori Y, Kanda H, Hidaka T, Kakamu T, Kumagai T, Hayakawa T, Osaki Y, Fukushima AT. EFFECT OF CYP2A6*4 GENETIC POLYMORPHISMS ON SMOKING BEHAVIORS AND NICOTINE DEPENDENCE IN A GENERAL POPULATION OF JAPANESE MEN. Fukushima J Med Sci 2015; 61:125-30. [PMID: 26370685 DOI: 10.5387/fms.2015-14] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES Nicotine in cigarettes is metabolized primarily by CYP2A6-catalyzed oxidation. The CYP2A6*4 allele, in which CYP2A6 is a homozygous whole-deletion variant, completely lacks enzyme activity. The aim of this study was to examine the effects of CYP2A6*4 genetic polymorphism on smoking behavior and nicotine dependence in a general population of Japanese men. METHODS The subjects were 124 healthy Japanese men who gave informed consent to give saliva samples. The survey items included general information, smoking behaviors and nicotine dependence. The polymerase chain reaction restriction fragment length polymorphism method was used to analyze the genetic polymorphisms of CYP2A6. The subjects were classified into two groups: Group W (CYP2A6*4 absence: *1A/*1A, *1A/*1B and *1B/*1B) and Group D (CYP2A6*4 presence: *1B/*4A, *4A/*4A, *1A/*4A or *1B/*4D, and *1A/*4D). We analyzed the differences in the survey items between the two groups. RESULTS There were no significant differences in smoking behaviors between the two groups. However, Group D tended to have less difficulty in refraining from smoking after waking in the morning compared to Group W (p=0.051). CONCLUSIONS CYP2A6*4 genetic polymorphisms may not strongly affect smoking behavior but may possibly have an effect on nicotine dependence.
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Affiliation(s)
- Teruna Ito
- Department of Hygiene and Preventive Medicine, Fukushima Medical University School of Medicine
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Pan L, Yang X, Li S, Jia C. Association of CYP2A6 gene polymorphisms with cigarette consumption: a meta-analysis. Drug Alcohol Depend 2015; 149:268-71. [PMID: 25683822 DOI: 10.1016/j.drugalcdep.2015.01.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 01/20/2015] [Accepted: 01/22/2015] [Indexed: 11/29/2022]
Abstract
AIMS A meta-analysis was performed to assess the association of hepatic cytochrome P450 2A6 (CYP2A6) gene polymorphisms with cigarette consumption. METHODS A comprehensive search was conducted to identify the studies of the above-mentioned association. The fixed effect model (FEM) or random effect model (REM) was selected based on the homogeneity test among studies. Heterogeneity among studies was evaluated using the I(2). Meta-regression and the "leave one out" sensitive analysis were utilized to explore potential sources of heterogeneity. Publication bias was estimated by Harbord test. The effect of CYP2A6 gene polymorphisms on cigarette consumption was presented as standardized mean difference (SMD) with 95% confidence intervals (CI). RESULTS After excluding one article that was the key contributor to between-study heterogeneity, there was a significant difference of cigarettes per day in groups of normal vs. reduced metabolizers of CYP2A6 gene (FEM: SMD = 0.134, 95%CI: 0.049-0.219). There was also a significant difference of age of smoking initiation between normal and intermediate metabolizers of CYP2A6 gene (FEM: SMD = 0.216, 95%CI: 0.056-0.377). No significant difference of tobacco dependence between normal and reduced metabolizers of CYP2A6 gene was found (FEM: SMD = 0.185, 95%CI = -0.001 to 0.371). CONCLUSION This meta-analysis suggests that CYP2A6 gene polymorphism is associated with daily cigarette consumption. Individuals with intermediate nicotine metabolism might also initiate smoking later than normal metabolism.
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Affiliation(s)
- Lulu Pan
- Department of Epidemiology, Shandong University, PR China
| | - Xiaorong Yang
- Department of Epidemiology, Shandong University, PR China
| | - Suyun Li
- Department of Epidemiology, Shandong University, PR China
| | - Chongqi Jia
- Department of Epidemiology, Shandong University, PR China.
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Lerman C, Schnoll RA, Hawk LW, Cinciripini P, George TP, Wileyto EP, Swan GE, Benowitz NL, Heitjan DF, Tyndale RF. Use of the nicotine metabolite ratio as a genetically informed biomarker of response to nicotine patch or varenicline for smoking cessation: a randomised, double-blind placebo-controlled trial. THE LANCET RESPIRATORY MEDICINE 2015; 3:131-138. [PMID: 25588294 DOI: 10.1016/s2213-2600(14)70294-2] [Citation(s) in RCA: 208] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
BACKGROUND Substantial variability exists in therapeutic response and adverse effects with pharmacotherapies for tobacco dependence. Biomarkers to optimise treatment choice for individual smokers might improve treatment outcomes. We tested whether a genetically informed biomarker of nicotine clearance, the nicotine metabolite ratio (NMR; 3'-hydroxycotinine:cotinine), predicts response to nicotine patch or varenicline for smoking cessation. METHODS We undertook NMR-stratified multicentre, randomised, placebo-controlled clinical trial from Nov 16, 2010, to Sept 12, 2014, at four sites. Smokers seeking treatment were randomly assigned by baseline NMR status and study site, in blocks of 12 patients (1:1:1 ratio), to 11 weeks of placebo (placebo pill plus placebo patch), nicotine patch (active patch plus placebo pill), or varenicline (active pill plus placebo patch), plus behavioural counselling. Participants and investigators were masked to group allocation and NMR status. An intention-to-treat analysis was done. Participants were followed up for 12 months after the target quit date. The primary endpoint was biochemically verified 7 day point prevalence abstinence at the end of treatment to estimate the pharmacological effect of treatment by NMR. The trial is registered at ClinicalTrials.gov, number NCT01314001. FINDINGS 1246 participants (662 slow metabolisers of nicotine, 584 normal metabolisers of nicotine) were enrolled and randomly assigned to the three interventions (408 placebo, 418 nicotine patch, 420 varenicline). At end of treatment, varenicline was more efficacious than nicotine patch in normal metabolisers (OR 2·17, 95% CI 1·38-3·42; p=0·001), but not in slow metabolisers (OR 1·13, 0·74-1·71; p=0·56). In the longitudinal model including all timepoints, the NMR-by-treatment interaction was significant (ratio of odds ratios [ORR] 1·96, 95% CI 1·11-3·46; p=0·02). An NMR-by-treatment interaction showed that slow (vs normal) metabolisers reported greater overall side-effect severity with varenicline versus placebo (β=-1·06, 95% CI -2·08 to -0·03; p=0·044). INTERPRETATION Treating normal metabolisers with varenicline and slow metabolisers with nicotine patch could optimise quit rates while minimising side-effects. FUNDING National Institutes of Health, Canadian Institutes of Health Research, Abramson Cancer Center, Centre for Addiction and Mental Health Foundation, and Pennsylvania Department of Health.
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Affiliation(s)
- Caryn Lerman
- Department of Psychiatry, Annenberg School for Communication, and Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA, USA.
| | - Robert A Schnoll
- Department of Psychiatry and Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA, USA
| | - Larry W Hawk
- Department of Psychology, University at Buffalo, SUNY, Buffalo, NY, USA
| | - Paul Cinciripini
- Department of Behavioral Science, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Tony P George
- Centre for Addiction and Mental Health and Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - E Paul Wileyto
- Department of Biostatistics & Epidemiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Gary E Swan
- Department of Medicine, Stanford University, Palo Alto, CA, USA
| | - Neal L Benowitz
- Departments of Medicine, and Bioengineering & Therapeutic Sciences, University of California, San Francisco, CA, USA
| | - Daniel F Heitjan
- Department of Biostatistics & Epidemiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Rachel F Tyndale
- Centre for Addiction and Mental Health and Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada
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Tanner JA, Chenoweth MJ, Tyndale RF. Pharmacogenetics of nicotine and associated smoking behaviors. Curr Top Behav Neurosci 2015; 23:37-86. [PMID: 25655887 DOI: 10.1007/978-3-319-13665-3_3] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This chapter summarizes genetic factors that contribute to variation in nicotine pharmacokinetics and nicotine's pharmacological action in the central nervous system (CNS), and how this in turn influences smoking behaviors. Nicotine, the major psychoactive compound in cigarette smoke, is metabolized by a number of enzymes, including CYP2A6, CYP2B6, FMOs, and UGTs, among others. Variation in the genes encoding these enzymes, in particular CYP2A6, can alter the rate of nicotine metabolism and smoking behaviors. Faster nicotine metabolism is associated with higher cigarette consumption and nicotine dependence, as well as lower quit rates. Variation in nicotine's CNS targets and downstream signaling pathways can also contribute to interindividual differences in smoking patterns. Binding of nicotine to neuronal nicotinic acetylcholine receptors (nAChRs) mediates the release of several neurotransmitters including dopamine and serotonin. Genetic variation in nAChRs, and in transporter and enzyme systems that leads to altered CNS levels of dopamine and serotonin, is associated with a number of smoking behaviors. To date, the precise mechanism underpinning many of these findings remains unknown. Considering the complex etiology of nicotine addiction, a more comprehensive approach that assesses the contribution of multiple gene variants, and their interaction with environmental factors, will likely improve personalized therapeutic approaches and increase smoking cessation rates.
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Affiliation(s)
- Julie-Anne Tanner
- Departments of Pharmacology and Toxicology and Psychiatry, University of Toronto, Toronto, ON, Canada
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Chen C, Wang DW. Cytochrome P450-CYP2 Family-Epoxygenase Role in Inflammation and Cancer. CYTOCHROME P450 FUNCTION AND PHARMACOLOGICAL ROLES IN INFLAMMATION AND CANCER 2015; 74:193-221. [DOI: 10.1016/bs.apha.2015.04.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Daly AK. Polymorphic Variants of Cytochrome P450. CYTOCHROME P450 FUNCTION AND PHARMACOLOGICAL ROLES IN INFLAMMATION AND CANCER 2015; 74:85-111. [DOI: 10.1016/bs.apha.2015.03.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Scherer G, Lee PN. Smoking behaviour and compensation: A review of the literature with meta-analysis. Regul Toxicol Pharmacol 2014; 70:615-28. [DOI: 10.1016/j.yrtph.2014.09.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 09/15/2014] [Accepted: 09/16/2014] [Indexed: 11/28/2022]
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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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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: 19] [Impact Index Per Article: 1.7] [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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Bass C, Zimmer CT, Riveron JM, Wilding CS, Wondji CS, Kaussmann M, Field LM, Williamson MS, Nauen R. Gene amplification and microsatellite polymorphism underlie a recent insect host shift. Proc Natl Acad Sci U S A 2013; 110:19460-5. [PMID: 24218582 PMCID: PMC3845143 DOI: 10.1073/pnas.1314122110] [Citation(s) in RCA: 149] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Host plant shifts of herbivorous insects may be a first step toward sympatric speciation and can create new pests of agriculturally important crops; however, the molecular mechanisms that mediate this process are poorly understood. Certain races of the polyphagous aphid Myzus persicae have recently adapted to feed on tobacco (Myzus persicae nicotianae) and show a reduced sensitivity to the plant alkaloid nicotine and cross-resistance to neonicotinoids a class of synthetic insecticides widely used for control. Here we show constitutive overexpression of a cytochrome P450 (CYP6CY3) allows tobacco-adapted races of M. persicae to efficiently detoxify nicotine and has preadapted them to resist neonicotinoid insecticides. CYP6CY3, is highly overexpressed in M. persicae nicotianae clones from three continents compared with M. persicae s.s. and expression level is significantly correlated with tolerance to nicotine. CYP6CY3 is highly efficient (compared with the primary human nicotine-metabolizing P450) at metabolizing nicotine and neonicotinoids to less toxic metabolites in vitro and generation of transgenic Drosophila expressing CYP6CY3 demonstrate that it confers resistance to both compounds in vivo. Overexpression of CYP6CY3 results from the expansion of a dinucleotide microsatellite in the promoter region and a recent gene amplification, with some aphid clones carrying up to 100 copies. We conclude that the mutations leading to overexpression of CYP6CY3 were a prerequisite for the host shift of M. persicae to tobacco and that gene amplification and microsatellite polymorphism are evolutionary drivers in insect host adaptation.
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Affiliation(s)
- Chris Bass
- Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden AL5 2JQ, United Kingdom
| | - Christoph T. Zimmer
- Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden AL5 2JQ, United Kingdom
- Pest Control Biology, Bayer CropScience AG, D40789 Monheim, Germany; and
| | - Jacob M. Riveron
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom
| | - Craig S. Wilding
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom
| | - Charles S. Wondji
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom
| | - Martin Kaussmann
- Pest Control Biology, Bayer CropScience AG, D40789 Monheim, Germany; and
| | - Linda M. Field
- Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden AL5 2JQ, United Kingdom
| | - Martin S. Williamson
- Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden AL5 2JQ, United Kingdom
| | - Ralf Nauen
- Pest Control Biology, Bayer CropScience AG, D40789 Monheim, Germany; and
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Cytochrome p450 metabolism of betel quid-derived compounds: implications for the development of prevention strategies for oral and pharyngeal cancers. ScientificWorldJournal 2013; 2013:618032. [PMID: 23983642 PMCID: PMC3747400 DOI: 10.1155/2013/618032] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 05/20/2013] [Indexed: 11/17/2022] Open
Abstract
Betel quid (BQ) products, with or without tobacco, have been classified by the International Agency for Research on Cancer (IARC) as group I human carcinogens that are associated with an elevated risk of oral potentially malignant disorders (OPMDs) and cancers of the oral cavity and pharynx. There are estimated 600 million BQ users worldwide. In Taiwan alone there are 2 million habitual users (approximately 10% of the population). Oral and pharyngeal cancers result from interactions between genes and environmental factors (BQ exposure). Cytochrome p450 (CYP) families are implicated in the metabolic activation of BQ- and areca nut-specific nitrosamines. In this review, we summarize the current knowledge base regarding CYP genetic variants and related oral disorders. In clinical applications, we focus on cancers of the oral cavity and pharynx and OPMDs associated with CYP gene polymorphisms, including CYP1A1, CYP2A6, CYP2E1, and CYP26B1. Our discussion of CYP polymorphisms provides insight into the importance of screening tests in OPMDs patients for the prevention of oral and pharyngeal cancers. Future studies will establish a strong foundation for the development of chemoprevention strategies, polymorphism-based clinical diagnostic tools (e.g., specific single-nucleotide polymorphism (SNP) "barcodes"), and effective treatments for BQ-related oral disorders.
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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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38
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Lung cancer risk in relation to nicotinic acetylcholine receptor, CYP2A6 and CYP1A1 genotypes in the Bangladeshi population. Clin Chim Acta 2013. [DOI: 10.1016/j.cca.2012.11.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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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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CYP2A6 and CYP2B6 genetic variation and its association with nicotine metabolism in South Western Alaska Native people. Pharmacogenet Genomics 2012; 22:429-40. [PMID: 22569203 DOI: 10.1097/fpc.0b013e3283527c1c] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
OBJECTIVES Alaska Native (AN) people have a high prevalence of tobacco use and associated morbidity and mortality when compared with the general USA population. Variations in the CYP2A6 and CYP2B6 genes, encoding enzymes responsible for nicotine metabolic inactivation and procarcinogen activation, have not been characterized in AN and may contribute toward the increased risk. METHODS AN people (n=400) residing in the Bristol Bay region of South Western Alaska were recruited for a cross-sectional study on tobacco use. They were genotyped for CYP2A6*1X2A, *1X2B, *1B, *2, *4, *7, *8, *9, *10, *12, *17, *35 and CYP2B6*4, *6, *9 and provided plasma and urine samples for the measurement of nicotine and metabolites. RESULTS CYP2A6 and CYP2B6 variant frequencies among the AN Yupik people (n=361) were significantly different from those in other ethnicities. Nicotine metabolism [as measured by the plasma and urinary ratio of metabolites trans-3'-hydroxycotinine to cotinine (3HC/COT)] was significantly associated with CYP2A6 (P<0.001), but not CYP2B6 genotype (P=0.95) when controlling for known covariates. It was noteworthy that the plasma 3HC/COT ratios were high in the entire Yupik people, and among the Yupik CYP2A6 wild-type participants, they were substantially higher than those in previously characterized racial/ethnic groups (P<0.001 vs. Caucasians and African Americans). CONCLUSION Yupik AN people have a unique CYP2A6 genetic profile that associated strongly with in-vivo nicotine metabolism. More rapid CYP2A6-mediated nicotine and nitrosamine metabolism in the Yupik people may modulate the risk of tobacco-related diseases.
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Simultaneous measurement of urinary total nicotine and cotinine as biomarkers of active and passive smoking among Japanese individuals. Environ Health Prev Med 2012; 18:244-50. [PMID: 23011941 DOI: 10.1007/s12199-012-0307-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 09/05/2012] [Indexed: 02/02/2023] Open
Abstract
OBJECTIVES Measuring urinary cotinine is a popular and established method of biologically monitoring exposure to tobacco smoke. However, the lower detection limit of cotinine often impedes the evaluation of passive (second-hand) smoking and this, together with unconverted nicotine, does not reflect actual levels of exposure. Furthermore, a portion of the Japanese population might have decreased ability to metabolize nicotine. The present study was therefore carried out to validate the simultaneous analysis of total concentrations of free nicotine and cotinine and their glucuronides to determine actual levels of voluntary and involuntary exposure to cigarette smoke. METHODS Urine samples from 118 Japanese smokers and 117 non-smokers were analyzed using gas chromatography-mass spectrometry. Voluntary and involuntary smoking status was self-reported and workplace smoking restrictions were objectively evaluated. RESULTS The integrated sum of all concentrations showed 2.2- and 2.4-fold higher total levels (free and glucuronide) of nicotine and cotinine relative to the free levels. Median (quartiles) of total nicotine and cotinine were 1635 (2222) and 3948 (3512) ng/mL in smokers, and 3.5 (5.3) and 2.8 (4.2) ng/mL in non-smokers. Concentrations of urinary nicotine were higher than those of cotinine in 21 % of smokers and in 54 % of non-smokers. Nicotine and cotinine levels were significantly associated with a smoking habit, as well as being significantly associated with the workplace and home environments of non-smokers. CONCLUSIONS The present method can monitor voluntary and involuntary exposure to tobacco smoke. Measuring total urinary nicotine levels might be useful for analyzing exposure to cigarette smoke among non-smokers.
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Williams JM, Gandhi KK, Lu SE, Steinberg ML, Benowitz NL. Nicotine intake and smoking topography in smokers with bipolar disorder. Bipolar Disord 2012; 14:618-27. [PMID: 22938167 PMCID: PMC3641517 DOI: 10.1111/j.1399-5618.2012.01047.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Cigarette smoking behavior in bipolar disorder (BPD), including the effects of mood-stabilizing medications, has not been well characterized. METHODS We compared serum nicotine, nicotine metabolite levels, and smoking topography in 75 smokers with BPD to 86 control smokers (CON). For some comparisons, an additional control group of 75 smokers with schizophrenia (SCZ) were included. RESULTS There were no differences between the BPD and CON groups in baseline smoking characteristics or serum nicotine or cotinine levels. Fifty-one smokers with BPD (68.9%) were taking one of the following mood stabilizers: valproic acid, lamotrigine, carbamazepine, oxcarbazepine, lithium, or topiramate. The 3-hydroxycotinine-to-cotinine ratio, a marker of cytochrome P450 2A6 (CYP2A6) metabolic activity, was significantly higher in BPD versus CON and versus SCZ (0.68 versus 0.49 versus 0.54; p =0.002). The difference between groups, however, was no longer significant when the analysis was repeated with those taking hepatic enzyme-inducing drugs (carbamazepine, oxcarbazepine, and topiramate) included as a covariate. The time between puffs, or interpuff interval (IPI), was shorter in BPD versus CON by an average of 3.0sec (p<0.05), although this was no longer significant when we removed smokers from the analysis of those taking hepatic enzyme inducers. CONCLUSIONS Smokers with BPD are not different from CON on most measures of nicotine intake and smoking topography. We found an increased rate of nicotine metabolism in smokers taking mood stabilizers that are hepatic enzyme inducers, including carbamazepine, oxcarbazepine, and topiramate. Smokers with rapid nicotine metabolism might be expected to smoke more intensely to compensate for the more rapid disappearance of nicotine from the blood and brain, and may have more difficulty in quitting smoking, although this requires further study.
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Affiliation(s)
- Jill M Williams
- University of Medicine and Dentistry of New Jersey (UMDNJ)-Robert Wood Johnson Medical School, New Brunswick, NJ 08901-2008, USA.
| | - Kunal K Gandhi
- UMDNJ–School of Public Health, New Brunswick, NJ,GlaxoSmithKline
| | - Shou-En Lu
- University of Medicine and Dentistry of New Jersey (UMDNJ)–Robert Wood Johnson Medical School, New Brunswick, NJ,UMDNJ–School of Public Health, New Brunswick, NJ
| | - Marc L Steinberg
- University of Medicine and Dentistry of New Jersey (UMDNJ)–Robert Wood Johnson Medical School, New Brunswick, NJ,UMDNJ–School of Public Health, New Brunswick, NJ
| | - Neal L Benowitz
- University of California at San Francisco, San Francisco, CA, USA
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Rapid nicotine clearance is associated with greater reward and heart rate increases from intravenous nicotine. Neuropsychopharmacology 2012; 37:1509-16. [PMID: 22334123 PMCID: PMC3327855 DOI: 10.1038/npp.2011.336] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The ratio of nicotine metabolites (trans-3'-hydroxycotinine (3HC) to cotinine) correlates with nicotine clearance. In previous studies, high nicotine metabolite ratio (NMR) predicted poor outcomes for smoking cessation treatment with nicotine patch. The underlying mechanisms that associate NMR with treatment outcomes have not been fully elucidated. A total of 100 smokers were divided into quartiles based on their baseline plasma NMR. Following overnight abstinence, smokers received saline followed by escalating intravenous doses of nicotine (0.5 and 1.0 mg/70 kg) given 30 min apart. The effects of nicotine on subjective, plasma cortisol, heart rate, and systolic and diastolic blood pressure measures were obtained. Smokers in the first NMR quartile (slower metabolizers) had lower Fagerstrom Test for Nicotine Dependence (FTND) scores, suggesting lower levels of dependence. In contrast, smokers in the fourth NMR quartile (faster metabolizers) reported greater craving for cigarettes following overnight abstinence from smoking and reported greater ratings of nicotine-induced good drug effects, drug liking, and wanting more drug. Higher NMR was also associated with greater heart rate increases in response to nicotine. These results suggest that enhanced nicotine reward and cigarette craving may contribute to the poor treatment response in smokers with high NMR. These findings warrant further investigation, especially in treatment-seeking smokers undergoing cessation treatment.
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Portugal GS, Wilkinson DS, Turner JR, Blendy JA, Gould TJ. Developmental effects of acute, chronic, and withdrawal from chronic nicotine on fear conditioning. Neurobiol Learn Mem 2012; 97:482-94. [PMID: 22521799 DOI: 10.1016/j.nlm.2012.04.003] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 03/09/2012] [Accepted: 04/03/2012] [Indexed: 10/28/2022]
Abstract
Pre-adolescence and adolescence are developmental periods associated with increased vulnerability for tobacco addiction, and exposure to tobacco during these periods may lead to long-lasting changes in behavioral and neuronal plasticity. The present study examined the short- and long-term effects of nicotine and nicotine withdrawal on fear conditioning in pre-adolescent, adolescent, and adult mice, and potential underlying substrates that may mediate the developmental effects of nicotine, such as changes in nicotinic acetylcholine receptor (nAChR) binding, CREB expression, and nicotine metabolism. Age-related differences existed in sensitivity to the effects of acute nicotine, chronic nicotine and nicotine withdrawal on contextual fear conditioning (no changes in cued fear conditioning were seen); younger mice were more sensitive to the acute effects and less sensitive to the effects of nicotine withdrawal 24 h post treatment cessation. Developmental differences in nAChR binding were associated with the effects of nicotine withdrawal on contextual learning. Developmental differences in nicotine metabolism and CREB expression were also observed, but were not related to the effects of nicotine withdrawal on contextual learning 24 h post treatment. Chronic nicotine exposure during pre-adolescence or adolescence, however, produced long-lasting impairments in contextual learning that were observed during adulthood, whereas adult chronic nicotine exposure did not. These developmental effects could be related to changes in CREB. Overall, there is a developmental shift in the effects of nicotine on hippocampus-dependent learning and developmental exposure to nicotine results in adult cognitive deficits; these changes in cognition may play an important role in the development and maintenance of nicotine addiction.
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Affiliation(s)
- George S Portugal
- Department of Psychology, Neuroscience Program, Temple University, Philadelphia, PA 19122, USA
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Gold AB, Lerman C. Pharmacogenetics of smoking cessation: role of nicotine target and metabolism genes. Hum Genet 2012; 131:10.1007/s00439-012-1143-9. [PMID: 22290489 PMCID: PMC3864572 DOI: 10.1007/s00439-012-1143-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Accepted: 01/19/2012] [Indexed: 11/24/2022]
Abstract
Many smokers attempt to quit smoking but few are successful in the long term. The heritability of nicotine addiction and smoking relapse have been documented, and research is focused on identifying specific genetic influences on the ability to quit smoking and response to specific medications. Research in genetically modified cell lines and mice has identified nicotine acetylcholine receptor subtypes that mediate the pharmacological and behavioral effects of nicotine sensitivity and withdrawal. Human genetic association studies have identified single nucleotide polymorphisms (SNPs) in genes encoding nicotine acetylcholine receptor subunits and nicotine metabolizing enzymes that influence smoking cessation phenotypes. There is initial promising evidence for a role in smoking cessation for SNPs in the β2 and α5/α3/β4 nAChR subunit genes; however, effects are small and not consistently replicated. There are reproducible and clinically significant associations of genotypic and phenotypic measures of CYP2A6 enzyme activity and nicotine metabolic rate with smoking cessation as well as response to nicotine replacement therapies and bupropion. Prospective clinical trials to identify associations of genetic variants and gene-gene interactions on smoking cessation are needed to generate the evidence base for both medication development and targeted therapy approaches based on genotype.
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Affiliation(s)
- Allison B. Gold
- Center for Interdisciplinary Research on Nicotine Addiction, University of Pennsylvania, 3535 Market Street, Suite 4100, Philadelphia, PA 19104, USA
| | - Caryn Lerman
- Center for Interdisciplinary Research on Nicotine Addiction, University of Pennsylvania, 3535 Market Street, Suite 4100, Philadelphia, PA 19104, USA
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Genetic polymorphisms affecting drug metabolism: recent advances and clinical aspects. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2012; 63:137-67. [PMID: 22776641 DOI: 10.1016/b978-0-12-398339-8.00004-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Though current knowledge of pharmacogenetic factors relevant to drug metabolism is fairly comprehensive and this should facilitate translation to the clinic, there are a number of gaps in knowledge. Recent studies using both conventional and novel approaches have added to our knowledge of pharmacogenetics of drug metabolism. Genome-wide association studies have provided new insights into the major contribution of cytochromes P450 to response to therapeutic agents such as coumarin anticoagulants and clopidogrel as well as to caffeine and nicotine. Recent advances in understanding of factors affecting gene expression, both regulation by transcription factors and by microRNA and epigenetic factors, have added to understanding of variation in expression of genes such as CYP3A4 and CYP2E1. The implementation of testing for pharmacogenetic polymorphisms in prescription of selected anticancer drugs and cardiovascular agents is considered in detail, with current controversies and barriers to implementation of pharmacogenetic testing assessed. Though genotyping for thiopurine methyltransferase is now common prior to prescription of thiopurines, genotyping for other pharmacogenetic polymorphisms prior to drug prescription remains uncommon. However, it seems likely that it will become more widespread as both increased evidence that certain pharmacogenetic tests are valuable and cost-effective and more accessible genotyping methods become available.
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Cho MH, Castaldi PJ, Wan ES, Siedlinski M, Hersh CP, Demeo DL, Himes BE, Sylvia JS, Klanderman BJ, Ziniti JP, Lange C, Litonjua AA, Sparrow D, Regan EA, Make BJ, Hokanson JE, Murray T, Hetmanski JB, Pillai SG, Kong X, Anderson WH, Tal-Singer R, Lomas DA, Coxson HO, Edwards LD, MacNee W, Vestbo J, Yates JC, Agusti A, Calverley PMA, Celli B, Crim C, Rennard S, Wouters E, Bakke P, Gulsvik A, Crapo JD, Beaty TH, Silverman EK. A genome-wide association study of COPD identifies a susceptibility locus on chromosome 19q13. Hum Mol Genet 2011; 21:947-57. [PMID: 22080838 DOI: 10.1093/hmg/ddr524] [Citation(s) in RCA: 180] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The genetic risk factors for chronic obstructive pulmonary disease (COPD) are still largely unknown. To date, genome-wide association studies (GWASs) of limited size have identified several novel risk loci for COPD at CHRNA3/CHRNA5/IREB2, HHIP and FAM13A; additional loci may be identified through larger studies. We performed a GWAS using a total of 3499 cases and 1922 control subjects from four cohorts: the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE); the Normative Aging Study (NAS) and National Emphysema Treatment Trial (NETT); Bergen, Norway (GenKOLS); and the COPDGene study. Genotyping was performed on Illumina platforms with additional markers imputed using 1000 Genomes data; results were summarized using fixed-effect meta-analysis. We identified a new genome-wide significant locus on chromosome 19q13 (rs7937, OR = 0.74, P = 2.9 × 10(-9)). Genotyping this single nucleotide polymorphism (SNP) and another nearby SNP in linkage disequilibrium (rs2604894) in 2859 subjects from the family-based International COPD Genetics Network study (ICGN) demonstrated supportive evidence for association for COPD (P = 0.28 and 0.11 for rs7937 and rs2604894), pre-bronchodilator FEV(1) (P = 0.08 and 0.04) and severe (GOLD 3&4) COPD (P = 0.09 and 0.017). This region includes RAB4B, EGLN2, MIA and CYP2A6, and has previously been identified in association with cigarette smoking behavior.
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Affiliation(s)
- Michael H Cho
- Channing Laboratory, Brigham & Women’s Hospital, Boston, MA 02115, USA.
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Verde Z, Santiago C, Rodríguez González-Moro JM, de Lucas Ramos P, López Martín S, Bandrés F, Lucia A, Gómez-Gallego F. 'Smoking genes': a genetic association study. PLoS One 2011; 6:e26668. [PMID: 22046326 PMCID: PMC3202555 DOI: 10.1371/journal.pone.0026668] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 09/30/2011] [Indexed: 11/19/2022] Open
Abstract
Some controversy exists on the specific genetic variants that are associated with nicotine dependence and smoking-related phenotypes. The purpose of this study was to analyse the association of smoking status and smoking-related phenotypes (included nicotine dependence) with 17 candidate genetic variants: CYP2A6*1×2, CYP2A6*2 (1799T>A) [rs1801272], CYP2A6*9 (-48T>G) [rs28399433], CYP2A6*12, CYP2A13*2 (3375C>T) [rs8192789], CYP2A13*3 (7520C>G), CYP2A13*4 (579G>A), CYP2A13*7 (578C>T) [rs72552266], CYP2B6*4 (785A>G), CYP2B6*9 (516G>T), CHRNA3 546C>T [rs578776], CHRNA5 1192G>A [rs16969968], CNR1 3764C>G [rs6928499], DRD2-ANKK1 2137G>A (Taq1A) [rs1800497], 5HTT LPR, HTR2A -1438A>G [rs6311] and OPRM1 118A>G [rs1799971]. We studied the genotypes of the aforementioned polymorphisms in a cohort of Spanish smokers (cases, N = 126) and ethnically matched never smokers (controls, N = 80). The results showed significant between-group differences for CYP2A6*2 and CYP2A6*12 (both P<0.001). Compared with carriers of variant alleles, the odds ratio (OR) for being a non-smoker in individuals with the wild-type genotype of CYP2A6*12 and DRD2-ANKK1 2137G>A (Taq1A) polymorphisms was 3.60 (95%CI: 1.75, 7.44) and 2.63 (95%CI: 1.41, 4.89) respectively. Compared with the wild-type genotype, the OR for being a non-smoker in carriers of the minor CYP2A6*2 allele was 1.80 (95%CI: 1.24, 2.65). We found a significant genotype effect (all P≤0.017) for the following smoking-related phenotypes: (i) cigarettes smoked per day and CYP2A13*3; (ii) pack years smoked and CYP2A6*2, CYP2A6*1×2, CYP2A13*7, CYP2B6*4 and DRD2-ANKK1 2137G>A (Taq1A); (iii) nicotine dependence (assessed with the Fagestrom test) and CYP2A6*9. Overall, our results suggest that genetic variants potentially involved in nicotine metabolization (mainly, CYP2A6 polymorphisms) are those showing the strongest association with smoking-related phenotypes, as opposed to genetic variants influencing the brain effects of nicotine, e.g., through nicotinic acetylcholine (CHRNA5), serotoninergic (HTR2A), opioid (OPRM1) or cannabinoid receptors (CNR1).
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Affiliation(s)
- Zoraida Verde
- Department of Biomedicine, Universidad Europea de Madrid, Villaviciosa de Odón, Comunidad de Madrid, Spain
| | - Catalina Santiago
- Department of Biomedicine, Universidad Europea de Madrid, Villaviciosa de Odón, Comunidad de Madrid, Spain
| | | | - Pilar de Lucas Ramos
- Department of Neumology, Hospital Gregorio Marañón, Madrid, Comunidad de Madrid, Spain
| | - Soledad López Martín
- Department of Neumology, Hospital Gregorio Marañón, Madrid, Comunidad de Madrid, Spain
| | - Fernando Bandrés
- Department of ‘Aula de Estudios Avanzados’, Fundación Tejerina, Madrid, Comunidad de Madrid, Spain
| | - Alejandro Lucia
- Department of Biomedicine, Universidad Europea de Madrid, Villaviciosa de Odón, Comunidad de Madrid, Spain
| | - Félix Gómez-Gallego
- Department of Biomedicine, Universidad Europea de Madrid, Villaviciosa de Odón, Comunidad de Madrid, Spain
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Positive and negative effects of alcohol and nicotine and their interactions: a mechanistic review. Neurotox Res 2011; 21:57-69. [PMID: 21932109 DOI: 10.1007/s12640-011-9275-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2011] [Revised: 08/14/2011] [Accepted: 08/31/2011] [Indexed: 12/30/2022]
Abstract
Nicotine and alcohol are two of the most commonly abused legal substances. Heavy use of one drug can often lead to, or is predictive of, heavy use of the other drug in adolescents and adults. Heavy drinking and smoking alone are of significant health hazard. The combination of the two, however, can result in synergistic adverse effects particularly in incidences of various cancers (e.g., esophagus). Although detrimental consequences of smoking are well established, nicotine by itself might possess positive and even therapeutic potential. Similarly, alcohol at low or moderated doses may confer beneficial health effects. These opposing findings have generated considerable interest in how these drugs act. Here we will briefly review the negative impact of drinking-smoking co-morbidity followed by factors that appear to contribute to the high rate of co-use of alcohol and nicotine. Our main focus will be on what research is telling us about the central actions and interactions of these drugs, and what has been elucidated about the mechanisms of their positive and negative effects. We will conclude by making suggestions for future research in this area.
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Portugal GS, Wilkinson DS, Kenney JW, Sullivan C, Gould TJ. Strain-dependent effects of acute, chronic, and withdrawal from chronic nicotine on fear conditioning. Behav Genet 2011; 42:133-50. [PMID: 21822688 DOI: 10.1007/s10519-011-9489-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Accepted: 07/14/2011] [Indexed: 12/15/2022]
Abstract
The effects of nicotine on cognitive processes such as learning and memory may play an important role in the addictive liability of tobacco. However, it remains unknown whether genetic variability modulates the effects of nicotine on learning and memory. The present study characterized the effects of acute, chronic, and withdrawal from chronic nicotine administration on fear conditioning, somatic signs, and the elevated plus maze in 8 strains of inbred mice. Strain-dependent effects of acute nicotine and nicotine withdrawal on contextual fear conditioning, somatic signs, and the elevated plus maze were observed, but no association between the effects of acute nicotine and nicotine withdrawal on contextual fear conditioning were observed, suggesting that different genetic substrates may mediate these effects. The identification of genetic factors that may alter the effects of nicotine on cognition may lead to more efficacious treatments for nicotine addiction.
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Affiliation(s)
- George S Portugal
- Department of Psychology, Neuroscience Program, Temple University, Weiss Hall, Philadelphia, PA 19122, USA
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