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Romero Villela PN, Evans LM, Palviainen T, Border R, Kaprio J, Palmer RHC, Keller MC, Ehringer MA. Loci on chromosome 20 interact with rs16969968 to influence cigarettes per day in European ancestry individuals. Drug Alcohol Depend 2024; 257:111126. [PMID: 38387257 PMCID: PMC11062023 DOI: 10.1016/j.drugalcdep.2024.111126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 01/12/2024] [Accepted: 02/07/2024] [Indexed: 02/24/2024]
Abstract
BACKGROUND The understanding of the molecular genetic contributions to smoking is largely limited to the additive effects of individual single nucleotide polymorphisms (SNPs), but the underlying genetic risk is likely to also include dominance, epistatic, and gene-environment interactions. METHODS To begin to address this complexity, we attempted to identify genetic interactions between rs16969968, the most replicated SNP associated with smoking quantity, and all SNPs and genes across the genome. RESULTS Using the UK Biobank European subsample, we found one SNP, rs1892967, and two genes, PCNA and TMEM230, that showed a significant genome-wide interaction with rs16969968 for log10 CPD and raw CPD, respectively, in a sample of 116 442 individuals who self-reported currently or previously smoking. We extended these analyses to individuals of South Asian descent and meta-analyzed the combined sample of 117 212 individuals of European and South Asian ancestry. We replicated the gene findings in a meta-analysis of five Finnish samples (N=40 140): FinHealth, FINRISK, Finnish Twin Cohort, GeneRISK, and Health-2000-2011. CONCLUSIONS To our knowledge, this represents the first reliable epistatic association between single nucleotide polymorphisms for smoking behaviors and provides a novel direction for possible future functional studies related to this interaction. Furthermore, this work demonstrates the feasibility of these analyses by pooling multiple datasets across various ancestries, which may be applied to other top SNPs for smoking and/or other phenotypes.
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Affiliation(s)
- Pamela N Romero Villela
- Institute for Behavioral Genetics, University of Colorado, Boulder, USA; Department of Psychology and Neuroscience, University of Colorado, Boulder, USA
| | - Luke M Evans
- Institute for Behavioral Genetics, University of Colorado, Boulder, USA; Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, USA
| | - Teemu Palviainen
- Institute for Molecular Medicine Finland FIMM, University of Helsinki, USA
| | - Richard Border
- Departments of Neurology and Computer Science, University of California, Los Angeles, USA
| | - Jaakko Kaprio
- Institute for Molecular Medicine Finland FIMM, University of Helsinki, USA
| | - Rohan H C Palmer
- Behavioral Genetics of Addiction Laboratory, Department of Psychology, Emory University, Atlanta, GA, USA
| | - Matthew C Keller
- Institute for Behavioral Genetics, University of Colorado, Boulder, USA; Department of Psychology and Neuroscience, University of Colorado, Boulder, USA
| | - Marissa A Ehringer
- Institute for Behavioral Genetics, University of Colorado, Boulder, USA; Departments of Neurology and Computer Science, University of California, Los Angeles, USA; Department of Integrative Physiology, University of Colorado, Boulder, USA.
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2
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Ferrari E, Cornali C, Fiorindi A, Agosti E, Gallone S, Rubino E, Ponzio F, Fontanella MM, De Maria L. Cigarette Smoking and Intracranial Aneurysms: A Pilot Analysis of SNPs in the CYP2A6 Gene in the Italian Population. World Neurosurg 2023; 179:e492-e499. [PMID: 37689358 DOI: 10.1016/j.wneu.2023.08.128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 08/28/2023] [Accepted: 08/31/2023] [Indexed: 09/11/2023]
Abstract
BACKGROUND Cigarette smoking is a modifiable risk factor associated with formation and rupture of intracranial aneurysms (IAs). Cytochrome P450 2A6 (CYP2A6) is the main enzyme implied in catabolism of nicotine and xenobiotics, giving rise to oxidative stress products. Our study investigated the associations between specific single-nucleotide polymorphisms (SNPs) in the CYP2A6 gene and the presence of sporadic IAs in a cluster of Italian patients, as well as their rupture regarding cigarette smoking habit. METHODS Three hundred and thirty-one Italian patients with sporadic IAs were recruited in a single institution. We recorded data on clinical onset with subarachnoid hemorrhage (SAH) and smoking habit. Genetic analysis was performed with a standard procedure on peripheral blood samples: CYP2A6 ∗1B2, CYP2A6 ∗2, and CYP2A6 ∗14 SNPs were analyzed in the study group along with 150 healthy control subjects. Statistical analysis was conducted according to genetic association study guidelines. RESULTS In the patient cohort, the frequency of aSAH was significantly higher in current smokers (P < 0.001; OR=17.45), regardless of the pattern of CYP2A6 SNPs. There was a correlation between IA rupture and cigarette smoking in patients with the heterozygous CYP2A6 ∗1B2 allele (P < 0.001; OR=15.47). All patients carrying the heterozygous CYP2A6 ∗14 allele had an aSAH event (100%), regardless of smoking habit, although this correlation was not statistically significant (P = 1). CONCLUSIONS According to our findings, a cigarette smoker carrying a fully active CYP2A6 enzyme (heterozygous ∗1B2 allele) may have an increased risk of IA rupture compared to those with functionally less active variants: further investigation on a larger sample is needed to verify this result. The role of the heterozygous CYP2A6 ∗14 allele in aSAH is yet to be clarified.
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Affiliation(s)
- Erika Ferrari
- Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Brescia, Italy
| | - Claudio Cornali
- Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Brescia, Italy
| | - Alessandro Fiorindi
- Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Brescia, Italy
| | - Edoardo Agosti
- Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Brescia, Italy
| | - Salvatore Gallone
- Department of Neuroscience "Rita Levi Montalcini", University of Torino, Turin, Italy
| | - Elisa Rubino
- Department of Neuroscience "Rita Levi Montalcini", University of Torino, Turin, Italy
| | - Francesco Ponzio
- Interuniversity Department of Regional and Urban Studies and Planning, Politecnico di Torino, Turin, Italy
| | - Marco Maria Fontanella
- Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Brescia, Italy
| | - Lucio De Maria
- Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Brescia, Italy.
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3
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Murphy SE. Biochemistry of nicotine metabolism and its relevance to lung cancer. J Biol Chem 2021; 296:100722. [PMID: 33932402 PMCID: PMC8167289 DOI: 10.1016/j.jbc.2021.100722] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 04/26/2021] [Accepted: 04/27/2021] [Indexed: 12/27/2022] Open
Abstract
Nicotine is the key addictive constituent of tobacco. It is not a carcinogen, but it drives smoking and the continued exposure to the many carcinogens present in tobacco. The investigation into nicotine biotransformation has been ongoing for more than 60 years. The dominant pathway of nicotine metabolism in humans is the formation of cotinine, which occurs in two steps. The first step is cytochrome P450 (P450, CYP) 2A6–catalyzed 5′-oxidation to an iminium ion, and the second step is oxidation of the iminium ion to cotinine. The half-life of nicotine is longer in individuals with low P450 2A6 activity, and smokers with low activity often decrease either the intensity of their smoking or the number of cigarettes they use compared with those with “normal” activity. The effect of P450 2A6 activity on smoking may influence one's tobacco-related disease risk. This review provides an overview of nicotine metabolism and a summary of the use of nicotine metabolite biomarkers to define smoking dose. Some more recent findings, for example, the identification of uridine 5′-diphosphoglucuronosyltransferase 2B10 as the catalyst of nicotine N-glucuronidation, are discussed. We also describe epidemiology studies that establish the contribution of nicotine metabolism and CYP2A6 genotype to lung cancer risk, particularly with respect to specific racial/ethnic groups, such as those with Japanese, African, or European ancestry. We conclude that a model of nicotine metabolism and smoking dose could be combined with other lung cancer risk variables to more accurately identify former smokers at the highest risk of lung cancer and to intervene accordingly.
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Affiliation(s)
- Sharon E Murphy
- Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota, USA.
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4
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Butler K, Chenoweth MJ, El-Boraie A, Giratallah H, Kowalczyk WJ, Heishman SJ, Tyndale RF, Le Foll B. Impact of CYP2A6 Activity on Nicotine Reinforcement and Cue-Reactivity in Daily Smokers. Nicotine Tob Res 2021; 23:1735-1743. [PMID: 33823003 DOI: 10.1093/ntr/ntab064] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 04/02/2021] [Indexed: 12/25/2022]
Abstract
INTRODUCTION Variation in CYP2A6, the primary enzyme responsible for nicotine metabolism, is associated with nicotine dependence, cigarette consumption, and abstinence outcomes in smokers. The impact of CYP2A6 activity on nicotine reinforcement and tobacco cue-reactivity, mechanisms that may contribute to these previous associations, has not been fully evaluated. AIMS AND METHODS CYP2A6 activity was indexed using 3 genetic approaches in 104 daily smokers completing forced-choice and cue-induced craving tasks assessing nicotine reinforcement and tobacco cue-reactivity, respectively. First, smokers were stratified by the presence or absence of reduced/loss-of-function CYP2A6 gene variants (normal vs. reduced metabolizers). As nicotine metabolite ratio (NMR) is a reliable biomarker of CYP2A6 activity, our second and third approaches used additional genetic variants identified in genome-wide association studies of NMR to create a weighted genetic risk score (wGRS) to stratify smokers (fast vs. slow metabolizers) and calculate a wGRS-derived NMR. RESULTS Controlling for race and sex, normal metabolizers (vs. reduced) selected a greater proportion of puffs from nicotine-containing cigarettes (vs. denicotinized) on the forced-choice task (p = .031). In confirmatory analyses, wGRS-based stratification (fast vs. slow metabolizers) produced similar findings. Additionally, wGRS-derived NMR, which correlated with actual NMR assessed in a subset of participants (n = 55), was positively associated with the proportion of puffs from nicotine-containing cigarettes controlling for race and sex (p = .015). None of the CYP2A6 indices were associated with tobacco cue-reactivity in minimally deprived smokers. CONCLUSIONS Findings suggest increased nicotine reinforcement is exhibited by smokers with high CYP2A6 activity, which may contribute to heavier smoking and poorer cessation outcomes previously reported in faster metabolizers. IMPLICATIONS CYP2A6 activity is a key determinant of smoking behavior and outcomes. Therefore, these findings support the targeting of CYP2A6 activity, either therapeutically or as a clinically relevant biomarker in a precision medicine approach, for tobacco use disorder treatment.
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Affiliation(s)
- Kevin Butler
- Translational Addiction Research Laboratory, Centre for Addiction and Mental Health, University of Toronto, Toronto, ON, Canada
| | - Meghan J Chenoweth
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Ahmed El-Boraie
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Haidy Giratallah
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - William J Kowalczyk
- National Institute on Drug Abuse, Intramural Research Program, Baltimore, MD, USA.,Department of Psychology, Hartwick College, Oneonta, NY, USA
| | - Stephen J Heishman
- National Institute on Drug Abuse, Intramural Research Program, Baltimore, MD, USA
| | - Rachel F Tyndale
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Bernard Le Foll
- Translational Addiction Research Laboratory, Centre for Addiction and Mental Health, University of Toronto, Toronto, ON, Canada.,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Acute Care Program, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Family and Community Medicine, University of Toronto, Toronto, ON, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
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5
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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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6
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Hubacek JA, Kurcova I, Maresova V, Pankova A, Stepankova L, Zvolska K, Lanska V, Kralikova E. SNPs within CHRNA5-A3-B4 and CYP2A6/B6, nicotine metabolite concentrations and nicotine dependence treatment success in smokers. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2019; 165:84-89. [PMID: 31796940 DOI: 10.5507/bp.2019.058] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 11/14/2019] [Indexed: 11/23/2022] Open
Abstract
AIM Plasma values of nicotine and its metabolites are highly variable, and this variability has a strong genetic influence. In our study, we analysed the impact of common polymorphisms associated with smoking on the plasma values of nicotine, nicotine metabolites and their ratios and investigated the potential effect of these polymorphisms and nicotine metabolite ratios on the successful treatment of tobacco dependence. METHODS Five variants (rs16969968, rs6474412, rs578776, rs4105144 and rs3733829) were genotyped in a group of highly dependent adult smokers (n=103). All smokers underwent intensive treatment for tobacco dependence; 33 smokers were still abstinent at the 12-month follow-up. RESULTS The rs4105144 (CYP2A6, P<0.005) and rs3733829 (EGLN2, P<0.05) variants were significantly associated with plasma concentrations of 3OH-cotinine and with 3OH-cotinine: cotinine ratios. Similarly, the unweighted gene score was a significant (P<0.05) predictor of both cotinine:nicotine and 3OH-cotinine:cotinine ratios. No associations between the analysed polymorphisms or nicotine metabolite ratios and nicotine abstinence rate were observed. CONCLUSION Although CYP2A6 and EGLN2 polymorphisms were associated with nicotine metabolism ratios, neither these polymorphisms nor the ratios were associated with abstinence rates.
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Affiliation(s)
- Jaroslav A Hubacek
- Centre for Experimental Medicine, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Ivana Kurcova
- Department of Toxicology and Forensic Medicine, 1st Faculty of Medicine, Charles University and General University Hospital in Prague, Czech Republic
| | - Vera Maresova
- Department of Toxicology and Forensic Medicine, 1st Faculty of Medicine, Charles University and General University Hospital in Prague, Czech Republic
| | - Alexandra Pankova
- Centre for Tobacco-Dependent, 3rd Department of Medicine - Department of Endocrinology and Metabolism, 1st Faculty of Medicine, Charles University and the General University Hospital in Prague, Czech Republic.,Institute of Hygiene and Epidemiology, 1st Faculty of Medicine, Charles University and the General University Hospital in Prague, Czech Republic
| | - Lenka Stepankova
- Centre for Tobacco-Dependent, 3rd Department of Medicine - Department of Endocrinology and Metabolism, 1st Faculty of Medicine, Charles University and the General University Hospital in Prague, Czech Republic
| | - Kamila Zvolska
- Centre for Tobacco-Dependent, 3rd Department of Medicine - Department of Endocrinology and Metabolism, 1st Faculty of Medicine, Charles University and the General University Hospital in Prague, Czech Republic
| | - Vera Lanska
- Statistical Unit, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Eva Kralikova
- Centre for Tobacco-Dependent, 3rd Department of Medicine - Department of Endocrinology and Metabolism, 1st Faculty of Medicine, Charles University and the General University Hospital in Prague, Czech Republic.,Institute of Hygiene and Epidemiology, 1st Faculty of Medicine, Charles University and the General University Hospital in Prague, Czech Republic
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7
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Stancil SL, Pearce RE, Tyndale RF, Kearns GL, Vyhlidal CA, Leeder JS, Abdel-Rahman S. Evaluating metronidazole as a novel, safe CYP2A6 phenotyping probe in healthy adults. Br J Clin Pharmacol 2019; 85:960-969. [PMID: 30706508 DOI: 10.1111/bcp.13884] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 01/21/2019] [Accepted: 01/23/2019] [Indexed: 01/18/2023] Open
Abstract
AIMS CYP2A6 is a genetically polymorphic enzyme resulting in differential substrate metabolism and health behaviours. Current phenotyping probes for CYP2A6 exhibit limitations related to procurement (deuterated cotinine), toxicity (coumarin), specificity (caffeine) and age-appropriate administration (nicotine, NIC). In vitro, CYP2A6 selectively forms 2-hydroxymetronidazole (2HM) from metronidazole (MTZ). The purpose of this study was to evaluate MTZ as a CYP2A6 phenotyping probe drug in healthy adults against the well-established method of measuring trans-3-hydroxycotinine (3HC)/cotinine (COT). METHODS A randomized, cross-over, pharmacokinetic study was completed in 16 healthy, nonsmoking adults. Separated by a washout period of at least 2 weeks, MTZ 500 mg and NIC gum 2 mg were administered and plasma was sampled over 48 hours and 8 hours, respectively. Correlations of plasma metabolite/parent ratios (2HM/MTZ; 3HC/COT) were assessed by Pearson coefficient. CYP2A6 genotyping was conducted and incorporated as a variable of plasma ratio response. RESULTS Correlations between the plasma ratio 2HM/MTZ and 3HC/COT were ≥ 0.9 at multiple time points (P < 0.001), demonstrating a wide window during which 2HM/MTZ can be queried post-MTZ dose. CYP2A6 genotype had significant impacts on both MTZ and NIC phenotyping ratios with decreased activity predicted phenotypes demonstrating 2HM/MTZ ratios ≤58% and 3HC/COT ratios ≤56% compared with extensive activity predicted phenotypes at all time points examined in the study (P < 0.05). No adverse events were reported in the MTZ arm while 38% (n = 6) of participants reported mild adverse events in the NIC arm. CONCLUSIONS Metronidazole via 2HM/MTZ performed well as a novel, safe phenotyping probe for CYP2A6 in healthy adults.
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Affiliation(s)
- Stephani L Stancil
- Division of Adolescent Medicine, Children's Mercy Kansas City, MO, USA.,Division of Clinical Pharmacology, Toxicology and Therapeutic Innovation, Children's Mercy Kansas City, MO, USA.,Division of Pharmacology & Toxicology, University of Missouri-Kansas City School of Pharmacy, Kansas City, MO, USA
| | - Robin E Pearce
- Division of Clinical Pharmacology, Toxicology and Therapeutic Innovation, Children's Mercy Kansas City, MO, USA.,Department of Pediatrics, University of Missouri-Kansas City School of Medicine, MO, USA
| | - Rachel F Tyndale
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Departments of Pharmacology & Toxicology, and Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Gregory L Kearns
- Arkansas Children's Research Institute and the Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Carrie A Vyhlidal
- Division of Clinical Pharmacology, Toxicology and Therapeutic Innovation, Children's Mercy Kansas City, MO, USA.,Department of Pediatrics, University of Missouri-Kansas City School of Medicine, MO, USA
| | - J Steven Leeder
- Division of Clinical Pharmacology, Toxicology and Therapeutic Innovation, Children's Mercy Kansas City, MO, USA.,Department of Pediatrics, University of Missouri-Kansas City School of Medicine, MO, USA
| | - Susan Abdel-Rahman
- Division of Clinical Pharmacology, Toxicology and Therapeutic Innovation, Children's Mercy Kansas City, MO, USA.,Department of Pediatrics, University of Missouri-Kansas City School of Medicine, MO, USA
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8
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Tanner JA, Tyndale RF. Variation in CYP2A6 Activity and Personalized Medicine. J Pers Med 2017; 7:jpm7040018. [PMID: 29194389 PMCID: PMC5748630 DOI: 10.3390/jpm7040018] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 11/17/2017] [Accepted: 11/27/2017] [Indexed: 12/16/2022] Open
Abstract
The cytochrome P450 2A6 (CYP2A6) enzyme metabolizes several clinically relevant substrates, including nicotine-the primary psychoactive component in cigarette smoke. The gene that encodes the CYP2A6 enzyme is highly polymorphic, resulting in extensive interindividual variation in CYP2A6 enzyme activity and the rate of metabolism of nicotine and other CYP2A6 substrates including cotinine, tegafur, letrozole, efavirenz, valproic acid, pilocarpine, artemisinin, artesunate, SM-12502, caffeine, and tyrosol. CYP2A6 expression and activity are also impacted by non-genetic factors, including induction or inhibition by pharmacological, endogenous, and dietary substances, as well as age-related changes, or interactions with other hepatic enzymes, co-enzymes, and co-factors. As variation in CYP2A6 activity is associated with smoking behavior, smoking cessation, tobacco-related lung cancer risk, and with altered metabolism and resulting clinical responses for several therapeutics, CYP2A6 expression and enzyme activity is an important clinical consideration. This review will discuss sources of variation in CYP2A6 enzyme activity, with a focus on the impact of CYP2A6 genetic variation on metabolism of the CYP2A6 substrates.
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Affiliation(s)
- Julie-Anne Tanner
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, ON M5T 1R8, Canada.
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada.
| | - Rachel F Tyndale
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, ON M5T 1R8, Canada.
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada.
- Department of Psychiatry, University of Toronto, Toronto, ON M5T 1R8, Canada.
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9
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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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Hosono H, Kumondai M, Maekawa M, Yamaguchi H, Mano N, Oda A, Hirasawa N, Hiratsuka M. Functional Characterization of 34 CYP2A6 Allelic Variants by Assessment of Nicotine C-Oxidation and Coumarin 7-Hydroxylation Activities. Drug Metab Dispos 2016; 45:279-285. [PMID: 27974382 DOI: 10.1124/dmd.116.073494] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 12/13/2016] [Indexed: 11/22/2022] Open
Abstract
CYP2A6, a member of the cytochrome P450 (P450) family, is one of the enzymes responsible for the metabolism of therapeutic drugs and such tobacco components as nicotine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, and N-nitrosodiethylamine. Genetic polymorphisms in CYP2A6 are associated with individual variation in smoking behavior, drug toxicities, and the risk of developing several cancers. In this study, we conducted an in vitro analysis of 34 allelic variants of CYP2A6 using nicotine and coumarin as representative CYP2A6 substrates. These variant CYP2A6 proteins were heterologously expressed in 293FT cells, and their enzymatic activities were assessed on the basis of nicotine C-oxidation and coumarin 7-hydroxylation activities. Among the 34 CYP2A6 variants, CYP2A6.2, CYP2A6.5, CYP2A6.6, CYP2A6.10, CYP2A6.26, CYP2A6.36, and CYP2A6.37 exhibited no enzymatic activity, whereas 14 other variants exhibited markedly reduced activity toward both nicotine and coumarin. These comprehensive in vitro findings may provide useful insight into individual differences in smoking behavior, drug efficacy, and cancer susceptibility.
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Affiliation(s)
- Hiroki Hosono
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (H.H., M.K., N.H., M.H.), Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, Japan (M.M., H.Y., N.M.), Department of Biophysical Chemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan (A.O.)
| | - Masaki Kumondai
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (H.H., M.K., N.H., M.H.), Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, Japan (M.M., H.Y., N.M.), Department of Biophysical Chemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan (A.O.)
| | - Masamitsu Maekawa
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (H.H., M.K., N.H., M.H.), Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, Japan (M.M., H.Y., N.M.), Department of Biophysical Chemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan (A.O.)
| | - Hiroaki Yamaguchi
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (H.H., M.K., N.H., M.H.), Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, Japan (M.M., H.Y., N.M.), Department of Biophysical Chemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan (A.O.)
| | - Nariyasu Mano
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (H.H., M.K., N.H., M.H.), Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, Japan (M.M., H.Y., N.M.), Department of Biophysical Chemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan (A.O.)
| | - Akifumi Oda
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (H.H., M.K., N.H., M.H.), Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, Japan (M.M., H.Y., N.M.), Department of Biophysical Chemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan (A.O.)
| | - Noriyasu Hirasawa
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (H.H., M.K., N.H., M.H.), Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, Japan (M.M., H.Y., N.M.), Department of Biophysical Chemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan (A.O.)
| | - Masahiro Hiratsuka
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (H.H., M.K., N.H., M.H.), Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, Japan (M.M., H.Y., N.M.), Department of Biophysical Chemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan (A.O.)
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Patel YM, Park SL, Han Y, Wilkens LR, Bickeböller H, Rosenberger A, Caporaso N, Landi MT, Brüske I, Risch A, Wei Y, Christiani DC, Brennan P, Houlston R, McKay J, McLaughlin J, Hung R, Murphy S, Stram DO, Amos C, Le Marchand L. Novel Association of Genetic Markers Affecting CYP2A6 Activity and Lung Cancer Risk. Cancer Res 2016; 76:5768-5776. [PMID: 27488534 PMCID: PMC5050097 DOI: 10.1158/0008-5472.can-16-0446] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 06/10/2016] [Indexed: 01/28/2023]
Abstract
Metabolism of nicotine by cytochrome P450 2A6 (CYP2A6) is a suspected determinant of smoking dose and, consequently, lung cancer risk. We conducted a genome-wide association study (GWAS) of CYP2A6 activity, as measured by the urinary ratio of trans-3'-hydroxycotinine and its glucuronide conjugate over cotinine (total 3HCOT/COT), among 2,239 smokers in the Multiethnic Cohort (MEC) study. We identified 248 CYP2A6 variants associated with CYP2A6 activity (P < 5 × 10-8). CYP2A6 activity was correlated (r = 0.32; P < 0.0001) with total nicotine equivalents (a measure of nicotine uptake). When we examined the effect of these variants on lung cancer risk in the Transdisciplinary Research in Cancer of the Lung (TRICL) consortium GWAS dataset (13,479 cases and 43,218 controls), we found that the vast majority of these individual effects were directionally consistent and associated with an increased lung cancer risk. Two hundred and twenty-six of the 248 variants associated with CYP2A6 activity in the MEC were available in TRICL. Of them, 81% had directionally consistent risk estimates, and six were globally significantly associated with lung cancer. When conditioning on nine known functional variants and two deletions, the top two SNPs (rs56113850 in MEC and rs35755165 in TRICL) remained significantly associated with CYP2A6 activity in MEC and lung cancer in TRICL. The present data support the hypothesis that a greater CYP2A6 activity causes smokers to smoke more extensively and be exposed to higher levels of carcinogens, resulting in an increased risk for lung cancer. Although the variants identified in these studies may be used as risk prediction markers, the exact causal variants remain to be identified. Cancer Res; 76(19); 5768-76. ©2016 AACR.
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Affiliation(s)
- Yesha M Patel
- Department of Preventive Medicine and Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Sunghim L Park
- Department of Preventive Medicine and Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Younghun Han
- Department of Biomedical Data Science, Dartmouth College, Hanover, New Hampshire
| | - Lynne R Wilkens
- Epidemiology Program, University of Hawai'i Cancer Center, Honolulu, Hawaii
| | - Heike Bickeböller
- Department of Genetic Epidemiology, University Medical Center, Georg-August-University Göttingen, Göttingen, Germany
| | - Albert Rosenberger
- Department of Genetic Epidemiology, University Medical Center, Georg-August-University Göttingen, Göttingen, Germany
| | - Neil Caporaso
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Maria Teresa Landi
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Irene Brüske
- Helmholtz Centre Munich, German Research Centre for Environmental Health, Institute of Epidemiology I, Neuherberg, Germany
| | - Angela Risch
- Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - Yongyue Wei
- Nanjing Medical University School of Public Health, Nanjing, China
| | - David C Christiani
- Massachusetts General Hospital, Boston, Massachusetts. Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts
| | - Paul Brennan
- Genetic Epidemiology Group, International Agency for Research on Cancer (IARC), Lyon, France
| | - Richard Houlston
- Division of Genetics and Epidemiology, The Institute of Cancer Research, London, United Kingdom
| | - James McKay
- Genetic Epidemiology Group, International Agency for Research on Cancer (IARC), Lyon, France
| | | | - Rayjean Hung
- Lunenfeld-Tanenbaum Research Institute of Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Sharon Murphy
- Department of Biochemistry Molecular Biology and Biophysics and Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota
| | - Daniel O Stram
- Department of Preventive Medicine and Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Christopher Amos
- Department of Biomedical Data Science, Dartmouth College, Hanover, New Hampshire
| | - Loïc Le Marchand
- Epidemiology Program, University of Hawai'i Cancer Center, Honolulu, Hawaii.
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Abstract
Driven by new regulatory demands to demonstrate risk reduction, the toxicity assessment of tobacco products increasingly employs innovative in vitro methods, including biphasic cell and tissue cultures exposed to whole cigarette smoke at the air-liquid interface, cell transformation assays, and genomic analyses. At the same time, novel tobacco products are increasingly compared to traditional cigarettes. This overview of in vitro toxicology studies of tobacco products reported in the last five years provides evidence to support the prioritisation of in vitro over in vivo methods by industry and their recommendation by regulatory authorities.
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