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Ding ZM, Neslund EM, Sun D, Tan X. Methoxsalen inhibited the acquisition of nicotine self-administration: attenuation by cotinine replacement in rats. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.04.543614. [PMID: 37333320 PMCID: PMC10274622 DOI: 10.1101/2023.06.04.543614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Cigarette smoking remains the leading preventable cause of disease and death. Nicotine is the primary reinforcing ingredient in cigarettes sustaining addiction. Cotinine is the major metabolite of nicotine that produces a myriad of neurobehavioral effects. Cotinine supported self-administration and rats with a history of intravenous self-administration of cotinine exhibited relapse-like drug-seeking behavior, suggesting cotinine may also be reinforcing. To date, a potential contribution of cotinine to nicotine reinforcement remains unknown. Nicotine metabolism is mainly catalyzed by hepatic CYP2B1 enzyme in the rat and methoxsalen is a potent CYP2B1 inhibitor. The study tested the hypothesis that methoxsalen inbibits nicotine metabolism and self-administration, and that cotinine replacement attenuates the inhibitory effects of methoxsalen. Acute methoxsalen decreased plasma cotinine levels and increased nicotine levels following subcutaneous nicotine injection. Repeated methoxsalen reduced the acquisition of nicotine self-administration, leading to fewer nicotine infusions, disruption of lever differentiation, smaller total nicotine intake, and lower plasma cotinine levels. On the other hand, methoxsalen did not alter nicotine self-administration during the maintenance phase despite great reduction of plasma cotinine levels. Cotinine replacement by mixing cotinine with nicotine for self-administration dose-dependently increased plasma cotinine levels, counteracted effects of methoxsalen, and enhanced the acquisition of self-administration. Neither basal nor nicotine-induced locomotor activity was altered by methoxsalen. These results indicate that methoxsalen depressed cotinine formation from nicotine and the acquisition of nicotine self-administration, and that replacement of plasma cotinine attenuated the inhibitory effects of methoxsalen, suggesting that cotinine may contribute to the development of nicotine reinforcement.
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Affiliation(s)
- Zheng-Ming Ding
- Department of Anesthesiology & Perioperative Medicine, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
- Department of Pharmacology, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - Elizabeth M. Neslund
- Department of Anesthesiology & Perioperative Medicine, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - Dongxiao Sun
- Department of Pharmacology, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
- Penn State Mass Spectrometry Core Facility, Penn State University College of Medicine, Hershey, PA 17033, USA
| | - Xiaoying Tan
- Department of Anesthesiology & Perioperative Medicine, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
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2
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Nasrin S, Coates S, Bardhi K, Watson C, Muscat JE, Lazarus P. Inhibition of Nicotine Metabolism by Cannabidiol (CBD) and 7-Hydroxycannabidiol (7-OH-CBD). Chem Res Toxicol 2023; 36:177-187. [PMID: 36626330 PMCID: PMC9945182 DOI: 10.1021/acs.chemrestox.2c00259] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Indexed: 01/11/2023]
Abstract
Cannabis-based products have experienced notable increases in co-usage alongside tobacco products. Several cannabinoids exhibit inhibition of a number of cytochrome P450 (CYP) and UDP glucuronosyltransferase (UGT) enzymes, but few studies have examined their inhibition of enzymes involved in nicotine metabolism. The goal of the present study was to examine potential drug-drug interactions occurring in the nicotine metabolism pathway perpetrated by cannabidiol (CBD) and its active metabolite, 7-hydroxy-CBD (7-OH-CBD). The inhibitory effects of CBD and 7-OH-CBD were tested in microsomes from HEK293 cells overexpressing individual metabolizing enzymes and from human liver tissue. Assays with overexpressing microsomes demonstrated that CBD and 7-OH-CBD inhibited CYP-mediated nicotine metabolism. Binding-corrected IC50,u values for CBD inhibition of nicotine metabolism to cotinine and nornicotine, and cotinine metabolism to trans-3'-hydroxycotinine (3HC), were 0.27 ± 0.060, 0.23 ± 0.14, and 0.21 ± 0.14 μM, respectively, for CYP2A6; and 0.26 ± 0.17 and 0.029 ± 0.0050 μM for cotinine and nornicotine formation, respectively, for CYP2B6. 7-OH-CBD IC50,u values were 0.45 ± 0.18, 0.16 ± 0.08, and 0.78 ± 0.23 μM for cotinine, nornicotine, and 3HC formation, respectively, for CYP2A6, and 1.2 ± 0.44 and 0.11 ± 0.030 μM for cotinine and nornicotine formation, respectively, for CYP2B6. Similar IC50,u values were observed in HLM. Inhibition (IC50,u = 0.37 ± 0.06 μM) of 3HC to 3HC-glucuronide formation by UGT1A9 was demonstrated by CBD. Significant inhibition of nicotine metabolism pathways by CBD and 7-OH-CBD suggests that cannabinoids may inhibit nicotine metabolism, potentially impacting tobacco addiction and cessation.
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Affiliation(s)
- Shamema Nasrin
- Department
of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical
Sciences, Washington State University, Spokane, Washington99223, United States
| | - Shelby Coates
- Department
of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical
Sciences, Washington State University, Spokane, Washington99223, United States
| | - Keti Bardhi
- Department
of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical
Sciences, Washington State University, Spokane, Washington99223, United States
| | - Christy Watson
- Department
of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical
Sciences, Washington State University, Spokane, Washington99223, United States
| | - Joshua E. Muscat
- Penn
State Cancer Institute, Department of Public Health Sciences, Penn State University College of Medicine, Hershey, Pennsylvania17033, United States
| | - Philip Lazarus
- Department
of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical
Sciences, Washington State University, Spokane, Washington99223, United States
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3
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von Weymarn LB, Lu X, Thomson NM, LeMarchand L, Park SL, Murphy SE. Quantitation of Ten Urinary Nicotine Metabolites, Including 4-Hydroxy-4-(3-pyridyl) Butanoic Acid, a Product of Nicotine 2'-Oxidation, and CYP2A6 Activity in Japanese Americans, Native Hawaiians, and Whites. Chem Res Toxicol 2023; 36:313-321. [PMID: 36735658 PMCID: PMC10042446 DOI: 10.1021/acs.chemrestox.2c00413] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Smoking intensity varies across smokers and is influenced by individual variability in the metabolism of nicotine, the major addictive agent in tobacco. Therefore, lung cancer risk, which varies by racial ethnic group, is influenced by the primary catalyst of nicotine metabolism, cytochrome P450 2A6 (CYP2A6). In smokers, CYP2A6 catalyzes nicotine 5'-oxidation. In vitro, CYP2A6 also catalyzes, to a much lower extent, 2'-oxidation, which leads to the formation of 4-hydroxy-4-(3-pyridyl) butanoic acid (hydroxy acid). The urinary concentration of hydroxy acid has been quantified in only a few small studies of White smokers. To quantitatively assess the importance of nicotine 2'-oxidation in smokers, an LC-MS/MS-based method was developed for the analysis of nicotine and ten metabolites in urine. The concentrations of nicotine and these metabolites were measured in 303 smokers (99 Whites, 99 Native Hawaiians, and 105 Japanese Americans), and the relative metabolism of nicotine by four pathways was determined. Metabolism by these pathways was also compared across quartiles of CYP2A6 activity (measured as the plasma ratio of 3-hydroxycotinine to cotinine). As reported previously and consistent with their average CYP2A6 activity, nicotine 5'-oxidation was highest in Whites and lowest in Japanese Americans. Nicotine N-glucuronidation and N-oxidation increased with decreasing CYP2A6 activity. However, the relative urinary concentration of hydroxy acid (mean, 2.3%; 95% CI, 2.2-2.4%) did not vary by ethnic group or by CYP2A6 activity. In summary, CYP2A6 is not an important catalyst of nicotine 2'-oxidation in smokers, nor does nicotine 2'-oxidation compensate for decreased CYP2A6 activity.
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Affiliation(s)
- Linda B von Weymarn
- Department of Biochemistry Molecular Biology and Biophysics and Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, United States.,Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Xiaotong Lu
- Department of Biochemistry Molecular Biology and Biophysics and Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, United States.,Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Nicole M Thomson
- Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Loic LeMarchand
- Epidemiology Program, University of Hawaii Cancer Center, Honolulu, Hawaii 96813, United States
| | - Sungshim L Park
- Epidemiology Program, University of Hawaii Cancer Center, Honolulu, Hawaii 96813, United States
| | - Sharon E Murphy
- Department of Biochemistry Molecular Biology and Biophysics and Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, United States.,Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
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4
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Seemiller LR, Goldberg LR, Smith PB, Dennis J, Patterson AD, Gould TJ. Genetic differences in nicotine sensitivity and metabolism in C57BL/6J and NOD/ShiLtJ mouse strains. Neuropharmacology 2022; 221:109279. [PMID: 36208797 DOI: 10.1016/j.neuropharm.2022.109279] [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: 05/18/2022] [Revised: 09/13/2022] [Accepted: 09/28/2022] [Indexed: 11/08/2022]
Abstract
Genetic background impacts sensitivity to nicotine's rewarding and aversive effects and metabolism, which influences susceptibility to nicotine addiction. This is important because sensitivity to nicotine influences susceptibility to nicotine addiction. Thus, understanding genetic contribution to nicotine sensitivity can aid in identifying risk factors for nicotine addiction. Genetic variability in addiction phenotypes can be modeled in rodent systems, and comparisons of nicotine sensitivity in inbred mice can identify contributing genetic substrates. Our laboratory has identified differences in nicotine sensitivity in male mice from two inbred mouse strains, C57BL/6J and NOD/ShiLtJ. We found that the NOD/ShiLtJ strain experienced greater nicotine-induced locomotor depression and hypothermia than the C57BL/6J strain. To investigate possible differences in nicotine metabolism between strains, subjects were treated with acute nicotine and serum and urine samples were analyzed using LC-MS/MS to quantify nicotine and metabolites. This analysis revealed that NOD/ShiLtJ mice had similar serum nicotine but lower cotinine and 3'-hydroxycotinine levels after nicotine treatment when compared to C57BL/6J mice. Possible genetic factors mediating strain differences were identified by surveying nicotine sensitivity- and metabolism-related genes within the Mouse Phenome Database SNP retrieval tool. Polymorphisms were found in 15 of the 26 examined gene sequences. Liver expression levels of nicotine metabolism-related genes (Cyp2a5, Cyp2a4, and Aox1) were measured using qPCR. NOD/ShiLtJ mice showed lower expression of Cyp2a5 and Cyp2a4 and greater expression of Aox1 in liver tissue. These data demonstrate complex differences in nicotine sensitivity and metabolism driven by genetic differences between C57BL/6J and NOD/ShiLtJ inbred mouse strains.
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Affiliation(s)
- Laurel R Seemiller
- Department of Biobehavioral Health, Penn State University, University Park, PA, USA
| | - Lisa R Goldberg
- Department of Biobehavioral Health, Penn State University, University Park, PA, USA
| | - Phillip B Smith
- The Huck Institutes for the Life Sciences, Penn State University, University Park, PA, USA
| | - Jason Dennis
- Department of Biobehavioral Health, Penn State University, University Park, PA, USA
| | - Andrew D Patterson
- Department of Veterinary and Biomedical Sciences, Penn State University, University Park, PA, USA
| | - Thomas J Gould
- Department of Biobehavioral Health, Penn State University, University Park, PA, USA.
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5
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Nicotine Inhibits the Cytotoxicity and Genotoxicity of NNK Mediated by CYP2A13 in BEAS-2B Cells. Molecules 2022; 27:molecules27154851. [PMID: 35956805 PMCID: PMC9369970 DOI: 10.3390/molecules27154851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 07/24/2022] [Accepted: 07/25/2022] [Indexed: 12/02/2022] Open
Abstract
Both tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and nicotine can be metabolized by cytochrome P450 2A13 (CYP2A13). Previous studies have shown that nicotine has a potential inhibitory effect on the toxicity of NNK. However, due to the lack of CYP2A13 activity in conventional lung cell lines, there had been no systematic in vitro investigation for the key target organ, the lung. Here, BEAS-2B cells stably expressing CYP2A13 (B-2A13 cells) were constructed to investigate the effects of nicotine on the cytotoxicity and genotoxicity of NNK. The results showed more sensitivity for NNK-induced cytotoxicity in B-2A13 cells than in BEAS-2B and B-vector cells. NNK significantly induced DNA damage, cell cycle arrest, and chromosomal damage in B-2A13 cells, but had no significant effect on BEAS-2B cells and the vector control cells. The combination of different concentration gradient of nicotine without cytotoxic effects and a single concentration of NNK reduced or even counteracted the cytotoxicity and multi-dimensional genotoxicity in a dose-dependent manner. In conclusion, CYP2A13 caused the cytotoxicity and genotoxicity of NNK in BEAS-2B cells, and the addition of nicotine could inhibit the toxicity of NNK.
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Kovar L, Selzer D, Britz H, Benowitz N, St Helen G, Kohl Y, Bals R, Lehr T. Comprehensive Parent-Metabolite PBPK/PD Modeling Insights into Nicotine Replacement Therapy Strategies. Clin Pharmacokinet 2021; 59:1119-1134. [PMID: 32166575 PMCID: PMC7467963 DOI: 10.1007/s40262-020-00880-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Background Nicotine, the pharmacologically active substance in both tobacco and many electronic cigarette (e-cigarette) liquids, is responsible for the addiction that sustains cigarette smoking. With 8 million deaths worldwide annually, smoking remains one of the major causes of disability and premature death. However, nicotine also plays an important role in smoking cessation strategies. Objectives The aim of this study was to develop a comprehensive, whole-body, physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) model of nicotine and its major metabolite cotinine, covering various routes of nicotine administration, and to simulate nicotine brain tissue concentrations after the use of combustible cigarettes, e-cigarettes, nicotine gums, and nicotine patches. Methods A parent–metabolite, PBPK/PD model of nicotine for a non-smoking and a smoking population was developed using 91 plasma and brain tissue concentration–time profiles and 11 heart rate profiles. Among others, cytochrome P450 (CYP) 2A6 and 2B6 enzymes were implemented, including kinetics for CYP2A6 poor metabolizers. Results The model is able to precisely describe and predict both nicotine plasma and brain tissue concentrations, cotinine plasma concentrations, and heart rate profiles. 100% of the predicted area under the concentration–time curve (AUC) and maximum concentration (Cmax) values meet the twofold acceptance criterion with overall geometric mean fold errors of 1.12 and 1.15, respectively. The administration of combustible cigarettes, e-cigarettes, nicotine patches, and nicotine gums was successfully implemented in the model and used to identify differences in steady-state nicotine brain tissue concentration patterns. Conclusions Our PBPK/PD model may be helpful in further investigations of nicotine dependence and smoking cessation strategies. As the model represents the first nicotine PBPK/PD model predicting nicotine concentration and heart rate profiles after the use of e-cigarettes, it could also contribute to a better understanding of the recent increase in youth e-cigarette use. Electronic supplementary material The online version of this article (10.1007/s40262-020-00880-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lukas Kovar
- Clinical Pharmacy, Saarland University, Campus C2 2, 66123, Saarbrücken, Germany
| | - Dominik Selzer
- Clinical Pharmacy, Saarland University, Campus C2 2, 66123, Saarbrücken, Germany
| | - Hannah Britz
- Clinical Pharmacy, Saarland University, Campus C2 2, 66123, Saarbrücken, Germany
| | - Neal Benowitz
- Department of Medicine, University of California, San Francisco, CA, USA
| | - Gideon St Helen
- Department of Medicine, University of California, San Francisco, CA, USA
| | - Yvonne Kohl
- Fraunhofer Institute for Biomedical Engineering IBMT, Sulzbach, Germany
| | - Robert Bals
- Department of Internal Medicine V, Saarland University, Homburg, Germany
| | - Thorsten Lehr
- Clinical Pharmacy, Saarland University, Campus C2 2, 66123, Saarbrücken, Germany.
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7
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Eleftheriou C, Zacharia LC. Ginkgo biloba L. flavonoids inhibit CYP 2A5; potential dietary supplement for nicotine replacement therapy enhancement. Nat Prod Res 2021; 36:4210-4214. [PMID: 34498955 DOI: 10.1080/14786419.2021.1972419] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Smoking is a public health concern, and even though smoking cessation methods exist, nicotine replacement therapy (NRT) is often ineffective. Smoking behavior is related to the nicotine metabolizing enzyme (NME) P450 2A6 (mouse 2A5) polymorphisms. Accordingly, fast metabolizers are nicotine dependent, and have low quitting rates compared to slow metabolizers. In this study we examined the ability of Ginkgo biloba L (GB) and its constituents to inhibit the NME, using mouse liver microsomes containing the 2A5 enzyme. Our results indicate that GB can inhibit 2A5 (25% inhibition at 5%v/v), with the flavonoids quercetin, isorhamnetin, and kaempferol being responsible for this inhibition (23.5%, 10.7%, 25.2% inhibition at 60 ng/μL, respectively). Importantly, the flavonoids inhibited 2A5 via mechanism based inhibition (for quercetin 30 ng/μl inhibition increased from 20.8% to 26.9% within 15 minutes). Our results suggest that GB if consumed on a regular basis can help NRT enhancement particularly in fast nicotine metabolizers.
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Affiliation(s)
- Constantina Eleftheriou
- Department of Life and Health Sciences, School of Sciences and Engineering, University of Nicosia, Nicosia, Cyprus
| | - Lefteris C Zacharia
- Department of Life and Health Sciences, School of Sciences and Engineering, University of Nicosia, Nicosia, Cyprus
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8
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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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9
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Xia W, Kolli AR, Koshibu K, Martin F, Kondylis A, Kuczaj A, Tan WT, Yeo YS, Tan G, Teng C, Woon K, Schneider T, Talikka M, Phillips BW, Vanscheeuwijck P, Peitsch MC, Hoeng J. In Vivo Profiling of a Natural Alkaloid, Anatabine, in Rodents: Pharmacokinetics and Anti-Inflammatory Efficacy. JOURNAL OF NATURAL PRODUCTS 2021; 84:1012-1021. [PMID: 33706515 DOI: 10.1021/acs.jnatprod.0c01044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Natural alkaloids, a large class of plant-derived substances, have attracted considerable interest because of their pharmacological activities. In this study, the in vivo pharmacokinetics and anti-inflammatory profile of anatabine, a naturally occurring alkaloid, were characterized in rodents. Anatabine was found to be bioavailable and brain-penetrant following systemic administration. Following intraperitoneal (i.p.) administration (1, 2, and 5 mg/kg), anatabine caused a dose-dependent reduction in carrageenan-induced paw edema in rats; in mice, it inhibited the production of pro-inflammatory cytokines and simultaneously elevated the levels of an anti-inflammatory cytokine in a dose-dependent manner 2 h after lipopolysaccharide challenge. Furthermore, anatabine (∼10 and ∼20 mg/kg/day for 4 weeks; inhalation exposure) had effects in a murine model of multiple sclerosis, reducing neurological deficits and bodyweight loss. Comparative studies of the pharmacokinetics and anti-inflammatory activity of anatabine demonstrated its bioequivalence in rats following i.p. administration and inhalation exposure. This study not only provides the first detailed profile of anatabine pharmacokinetics in rodents but also comprehensively characterizes the anti-inflammatory activities of anatabine in acute and chronic inflammatory models. These findings provide a basis for further characterizing and optimizing the anti-inflammatory properties of anatabine.
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Affiliation(s)
- Wenhao Xia
- Philip Morris International Research Laboratories Pte Ltd, 50 Science Park Road, Singapore 117406
| | - Aditya Reddy Kolli
- Philip Morris Products S.A., Quai Jeanrenaud 5, Neuchatel, CH-2000, Switzerland
| | - Kyoko Koshibu
- Philip Morris Products S.A., Quai Jeanrenaud 5, Neuchatel, CH-2000, Switzerland
| | - Florian Martin
- Philip Morris Products S.A., Quai Jeanrenaud 5, Neuchatel, CH-2000, Switzerland
| | - Athanasios Kondylis
- Philip Morris Products S.A., Quai Jeanrenaud 5, Neuchatel, CH-2000, Switzerland
| | - Arkadiusz Kuczaj
- Philip Morris Products S.A., Quai Jeanrenaud 5, Neuchatel, CH-2000, Switzerland
| | - Wei Teck Tan
- Philip Morris International Research Laboratories Pte Ltd, 50 Science Park Road, Singapore 117406
| | - Ying Shan Yeo
- Philip Morris International Research Laboratories Pte Ltd, 50 Science Park Road, Singapore 117406
| | - Glenda Tan
- Philip Morris International Research Laboratories Pte Ltd, 50 Science Park Road, Singapore 117406
| | - Charles Teng
- Philip Morris International Research Laboratories Pte Ltd, 50 Science Park Road, Singapore 117406
| | - Kaing Woon
- Philip Morris International Research Laboratories Pte Ltd, 50 Science Park Road, Singapore 117406
| | - Thomas Schneider
- Philip Morris Products S.A., Quai Jeanrenaud 5, Neuchatel, CH-2000, Switzerland
| | - Marja Talikka
- Philip Morris Products S.A., Quai Jeanrenaud 5, Neuchatel, CH-2000, Switzerland
| | - Blaine W Phillips
- Philip Morris International Research Laboratories Pte Ltd, 50 Science Park Road, Singapore 117406
| | | | - Manuel C Peitsch
- Philip Morris Products S.A., Quai Jeanrenaud 5, Neuchatel, CH-2000, Switzerland
| | - Julia Hoeng
- Philip Morris Products S.A., Quai Jeanrenaud 5, Neuchatel, CH-2000, Switzerland
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10
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Juvonen RO, Jokinen EM, Huuskonen J, Kärkkäinen O, Raunio H, Pentikäinen OT. Molecular docking and oxidation kinetics of 3-phenyl coumarin derivatives by human CYP2A13. Xenobiotica 2021; 51:1207-1216. [PMID: 33703988 DOI: 10.1080/00498254.2021.1898700] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
CYP2A13 enzyme is expressed in human extrahepatic tissues, while CYP2A6 is a hepatic enzyme. Reactions catalyzed by CYP2A13 activate tobacco-specific nitrosamines and some other toxic xenobiotics in lungs.To compare oxidation characteristics and substrate-enzyme active site interactions in CYP2A13 vs CYP2A6, we evaluated CYP2A13 mediated oxidation characteristics of 23 coumarin derivatives and modelled their interactions at the enzyme active site.CYP2A13 did not oxidize six coumarin derivatives to corresponding fluorescent 7-hydroxycoumarins. The Km-values of the other coumarins varied 0.85-97 µM, Vmax-values of the oxidation reaction varied 0.25-60 min-1, and intrinsic clearance varied 26-6190 kL/min*mol CYP2A13). Km of 6-chloro-3-(3-hydroxyphenyl)-coumarin was 0.85 (0.55-1.15 95% confidence limit) µM and Vmax 0.25 (0.23-0.26) min-1, whereas Km of 6-hydroxy-3-(3-hydroxyphenyl)-coumarin was 10.9 (9.9-11.8) µM and Vmax 60 (58-63) min-1. Docking analyses demonstrated that 6-chloro or 6-methoxy and 3-(3-hydroxyphenyl) or 3-(4-trifluoromethylphenyl) substituents of coumarin increased affinity to CYP2A13, whereas 3-triazole or 3-(3-acetate phenyl) or 3-(4-acetate phenyl) substituents decreased it.The active site of CYP2A13 accepts more diversified types of coumarin substrates than the hepatic CYP2A6 enzyme. New sensitive and convenient profluorescent CYP2A13 substrates were identified, such as 6-chloro-3-(3-hydroxyphenyl)-coumarin having high affinity and 6-hydroxy-3-(3-hydroxyphenyl)-coumarin with high intrinsic clearance.
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Affiliation(s)
- Risto O Juvonen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Box 1627, 70211 Kuopio, Finland
| | - Elmeri M Jokinen
- Institute of Biomedicine, Faculty of Medicine, Integrative Physiology and Pharmacology, University of Turku, Kiinamyllynkatu 10, FI-20520 Turku, Finland
| | - Juhani Huuskonen
- University of Jyvaskyla, Department of Chemistry, P.O. Box 35, FI-40014, Finland
| | - Olli Kärkkäinen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Box 1627, 70211 Kuopio, Finland
| | - Hannu Raunio
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Box 1627, 70211 Kuopio, Finland
| | - Olli T Pentikäinen
- Institute of Biomedicine, Faculty of Medicine, Integrative Physiology and Pharmacology, University of Turku, Kiinamyllynkatu 10, FI-20520 Turku, Finland.,University of Jyvaskyla, Department of Chemistry, P.O. Box 35, FI-40014, Finland
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11
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Lkhagvadorj K, Meyer KF, Verweij LP, Kooistra W, Reinders-Luinge M, Dijkhuizen HW, de Graaf IAM, Plösch T, Hylkema MN. Prenatal smoke exposure induces persistent Cyp2a5 methylation and increases nicotine metabolism in the liver of neonatal and adult male offspring. Epigenetics 2020; 15:1370-1385. [PMID: 32573327 PMCID: PMC7678918 DOI: 10.1080/15592294.2020.1782655] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 05/12/2020] [Accepted: 05/15/2020] [Indexed: 02/08/2023] Open
Abstract
Prenatal smoke exposure (PSE) is a risk factor for nicotine dependence. One susceptibility gene for nicotine dependence is Cytochrome P450 (CYP) 2A6, an enzyme responsible for the conversion of nicotine to cotinine and nicotine clearance in the liver. Higher activity of the CYP2A6 enzyme is associated with nicotine dependence, but no research has addressed the PSE effects on the CYP2A6 gene or its mouse homologue Cyp2a5. We hypothesized that PSE affects Cyp2a5 promoter methylation, Cyp2a5 mRNA levels, and nicotine metabolism in offspring. We used a smoke-exposed pregnant mouse model. RNA, DNA, and microsomal protein were isolated from liver tissue of foetal, neonatal, and adult offspring. Enzyme activity, Cyp2a5 mRNA levels, and Cyp2a5 methylation status of six CpG sites within the promoter region were analysed via HPLC, RT-PCR, and bisulphite pyrosequencing. Our data show that PSE induced higher cotinine levels in livers of male neonatal and adult offspring compared to controls. PSE-induced cotinine levels in neonates correlated with Cyp2a5 mRNA expression and promoter methylation at CpG-7 and CpG+45. PSE increased methylation in almost all CpG sites in foetal offspring, and this effect persisted at CpG-74 in male neonatal and adult offspring. Our results indicate that male offspring of mothers which were exposed to cigarette smoke during pregnancy have a higher hepatic nicotine metabolism, which could be regulated by DNA methylation. Given the detected persistence into adulthood, extrapolation to the human situation suggests that sons born from smoking mothers could be more susceptible to nicotine dependence later in life.
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Affiliation(s)
- Khosbayar Lkhagvadorj
- Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- GRIAC Research Institute, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Department of Pulmonology and Allergology, Mongolian National University of Medical Sciences, Ulaanbaatar, Mongolia
| | - Karolin F. Meyer
- Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- GRIAC Research Institute, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Laura P. Verweij
- Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- GRIAC Research Institute, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Wierd Kooistra
- Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- GRIAC Research Institute, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Marjan Reinders-Luinge
- Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- GRIAC Research Institute, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Henk W. Dijkhuizen
- Faculty of Science and Engineering, University of Groningen, Groningen, The Netherlands
| | - Inge A. M. de Graaf
- Department of Pharmacokinetics, Toxicology, and Targeting, Groningen Research Institute of Pharmacy, University of Groningen, Groningen, The Netherlands
| | - Torsten Plösch
- Department of Obstetrics and Gynecology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Machteld N. Hylkema
- Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- GRIAC Research Institute, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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12
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Gao Y, Miksys S, Palmour RM, Tyndale RF. The Influence of Tobacco Smoke/Nicotine on CYP2A Expression in Human and African Green Monkey Lungs. Mol Pharmacol 2020; 98:658-668. [PMID: 33055223 DOI: 10.1124/molpharm.120.000100] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 09/17/2020] [Indexed: 11/22/2022] Open
Abstract
CYP2A enzymes metabolically inactivate nicotine and activate tobacco-derived procarcinogens [e.g., 4-[methylnitrosamino]-1-(3-pyridyl)-1-butanone]. Smoking decreases nicotine clearance, and chronic nicotine reduces hepatic CYP2A activity. However, little is known about the impact of smoking or nicotine on the expression of CYP2A in the lung. We investigated 1) the levels of human lung CYP2A mRNA in smokers versus nonsmokers and 2) the impact of daily nicotine treatment on lung CYP2A protein levels in African green monkeys (AGMs). Lung CYP2A13, CYP2A6, and CYP2A7 (and CYP1A2) mRNA levels in smokers and nonsmokers were assessed in Gene Expression Omnibus data sets (GSE30063, GSE108134, and GSE11784). The impact of chronic, twice-daily, subcutaneous nicotine at two doses (0.3 and 0.5 mg/kg) versus vehicle on lung CYP2A protein levels was assessed. The impact of ethanol self-administration was also investigated, with and without nicotine treatment. Smokers versus nonsmokers (from GSE30063 and GSE108134) had lower (1.04- to 1.12-fold) levels of lung CYP2A13, CYP2A6, and CYP2A7 (and higher CYP1A2) mRNA. Both doses of nicotine tested decreased AGM lung CYP2A protein (3- to 7-fold). Ethanol self-administration had no effect on AGM lung CYP2A protein, and there was no interaction between ethanol and nicotine. Our results suggest that smoking was associated with a reduction in human lung CYP2A13, CYP2A6, and CYP2A7 mRNA, consistent with the role of nicotine treatment in reducing AGM lung CYP2A protein. This regulation by smoking/nicotine will increase interindividual variation in lung CYP2A levels, which may impact the localized metabolism of inhaled drugs and tobacco smoke procarcinogens. SIGNIFICANCE STATEMENT: CYP2A13 and CYP2A6 are expressed in the lung and may contribute to local procarcinogen activation. Smokers had lower lung CYP2A mRNA levels compared with nonsmokers. Lung CYP2A protein expression was decreased by systemic treatment with nicotine. Decreased lung CYP2A expression may alter smoking-related lung cancer risk and tissue damage from other inhaled toxins. This novel regulatory impact of nicotine, including nicotine found in smoking-cessation nicotine-replacement therapies, may have potential benefits on smoking-related lung cancer risk.
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Affiliation(s)
- Yuan Gao
- Department of Pharmacology and Toxicology, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH) (Y.G., S.M., R.F.T.) and Department of Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada and Department of Psychiatry and Human Genetics, McGill University, Montreal, Quebec, Canada (R.M.P.)
| | - Sharon Miksys
- Department of Pharmacology and Toxicology, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH) (Y.G., S.M., R.F.T.) and Department of Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada and Department of Psychiatry and Human Genetics, McGill University, Montreal, Quebec, Canada (R.M.P.)
| | - Roberta M Palmour
- Department of Pharmacology and Toxicology, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH) (Y.G., S.M., R.F.T.) and Department of Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada and Department of Psychiatry and Human Genetics, McGill University, Montreal, Quebec, Canada (R.M.P.)
| | - Rachel F Tyndale
- Department of Pharmacology and Toxicology, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH) (Y.G., S.M., R.F.T.) and Department of Psychiatry (R.F.T.), University of Toronto, Toronto, Ontario, Canada and Department of Psychiatry and Human Genetics, McGill University, Montreal, Quebec, Canada (R.M.P.)
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13
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Nguyen K, Kanamori K, Shin CS, Hamid A, Lutfy K. The Impact of Sex on Changes in Plasma Corticosterone and Cotinine Levels Induced by Nicotine in C57BL/6J Mice. Brain Sci 2020; 10:brainsci10100705. [PMID: 33023022 PMCID: PMC7601418 DOI: 10.3390/brainsci10100705] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 09/28/2020] [Accepted: 10/01/2020] [Indexed: 12/12/2022] Open
Abstract
We assessed if there were any sex-related differences in the ability of nicotine to increase plasma corticosterone secretion after single or repeated nicotine administration. For single-dose studies, male and female mice were habituated to the test room for 1 h and injected with saline or nicotine (0.25 or 1 mg/kg, subcutaneously (s.c.)). In repeated-dosing studies, mice were injected with saline or nicotine (1 mg/kg, s.c.) once daily for six days, and, on day 7, received nicotine (1 mg/kg, s.c.). Mice were then euthanized 15 min later, and trunk blood was collected for the measurement of corticosterone, nicotine, and cotinine. Our results showed that saline or nicotine each significantly increased plasma corticosterone levels in both males and females, with a greater response in female mice. Plasma corticosterone levels were increased in male but not female mice after being treated repeatedly compared to single nicotine administration. The level of cotinine, a biomarker of nicotine use, was significantly higher in female than in male mice. Taken together, these novel findings suggest that female mice respond to nicotine and the stress of handling more than male mice and provide for the first-time quantitative data on male–female differences in nicotine-induced elevations of corticosterone and cotinine plasma levels.
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Affiliation(s)
- Khoa Nguyen
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, 309 East 2nd Street, Pomona, CA 91766, USA; (K.N.); (K.K.); (C.S.S.); (A.H.)
| | - Keiko Kanamori
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, 309 East 2nd Street, Pomona, CA 91766, USA; (K.N.); (K.K.); (C.S.S.); (A.H.)
- Lab Launch, 605 E. Huntington Drive, Suite # 103, Monrovia, CA 91016, USA
| | - Chang Sung Shin
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, 309 East 2nd Street, Pomona, CA 91766, USA; (K.N.); (K.K.); (C.S.S.); (A.H.)
| | - Abdul Hamid
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, 309 East 2nd Street, Pomona, CA 91766, USA; (K.N.); (K.K.); (C.S.S.); (A.H.)
| | - Kabirullah Lutfy
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, 309 East 2nd Street, Pomona, CA 91766, USA; (K.N.); (K.K.); (C.S.S.); (A.H.)
- Correspondence: ; Tel.: +1-(909)-469-5481
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Smith LC, George O. Advances in smoking cessation pharmacotherapy: Non-nicotinic approaches in animal models. Neuropharmacology 2020; 178:108225. [PMID: 32758566 DOI: 10.1016/j.neuropharm.2020.108225] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 06/26/2020] [Accepted: 06/28/2020] [Indexed: 12/22/2022]
Abstract
The landscape of worldwide tobacco use is changing, with a decrease in traditional smoking and an exponential rise in electronic cigarette use. No new nicotine cessation pharmacotherapies have come to market in the last 10 years. The current therapies that have been approved by the United States Food and Drug Administration for nicotine cessation include nicotine replacement therapy, varenicline, a nicotinic acetylcholine receptor partial agonist, and the atypical antidepressant bupropion. Nicotine replacement therapy and varenicline both act on nicotinic acetylcholine receptors. Bupropion inhibits the dopamine transporter, the norepinephrine transporter, and the nicotinic acetylcholine receptors to inhibit smoking behavior. Notwithstanding these treatments, rates of successful nicotine cessation in clinical trials remain low. Recent pharmacological approaches to improve nicotine cessation rates in animal models have turned their focus away from activating nicotinic acetylcholine receptors. The present review focuses on such pharmacological approaches, including nicotine vaccines, anti-nicotine antibodies, nicotine-degrading enzymes, cannabinoids, and metformin. Both immunopharmacological and enzymatic approaches rely on restricting and degrading nicotine within the periphery, thus preventing psychoactive effects of nicotine on the central nervous system. In contrast, pharmacologic inhibition of the enzymes which degrade nicotine could affect smoking behavior. Cannabinoid receptor agonists and antagonists interact with the dopamine reward pathway and show efficacy in reducing nicotine addiction-like behaviors in preclinical studies. Metformin is currently approved by the Food and Drug Administration for the treatment of diabetes. It activates specific intracellular kinases that may protect against the lower metabolism, higher oxidation, and inflammation that are associated with nicotine withdrawal. Further studies are needed to investigate non-nicotinic targets to improve the treatment of tobacco use disorder. This article is part of the special issue on 'Contemporary Advances in Nicotine Neuropharmacology'.
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Affiliation(s)
- Lauren C Smith
- Department of Neuroscience, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA, 92037, USA; Department of Psychiatry, University of California, San Diego, School of Medicine, La Jolla, CA, 92093, USA
| | - Olivier George
- Department of Neuroscience, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA, 92037, USA; Department of Psychiatry, University of California, San Diego, School of Medicine, La Jolla, CA, 92093, USA.
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15
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The Multifarious Link between Cytochrome P450s and Cancer. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:3028387. [PMID: 31998435 PMCID: PMC6964729 DOI: 10.1155/2020/3028387] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 12/08/2019] [Accepted: 12/18/2019] [Indexed: 02/07/2023]
Abstract
Cancer is a leading cause of death worldwide. Cytochrome P450s (P450s) play an important role in the metabolism of endogenous as well as exogenous substances, especially drugs. Moreover, many P450s can serve as targets for disease therapy. Increasing reports of epidemiological, diagnostic, and clinical research indicate that P450s are enzymes that play a major part in the formation of cancer, prevention, and metastasis. The purposes of this review are to shed light on the current state of knowledge about the cancer molecular mechanism involving P450s and to summarize the link between the cancer effects and the participation of P450s.
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16
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Neves Cruz J, Santana de Oliveira M, Gomes Silva S, Pedro da Silva Souza Filho A, Santiago Pereira D, Lima E Lima AH, de Aguiar Andrade EH. Insight into the Interaction Mechanism of Nicotine, NNK, and NNN with Cytochrome P450 2A13 Based on Molecular Dynamics Simulation. J Chem Inf Model 2019; 60:766-776. [PMID: 31622091 DOI: 10.1021/acs.jcim.9b00741] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Tobacco smoke contains various cancer-causing toxic substances, including nicotine and nitrosamines 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN). The cytochrome 2A13 is involved in nicotine metabolism and in the activation of the pro-carcinogenic agents NNK and NNN, by means of α-hydroxylation reactions. Despite the significance of cytochrome 2A13 in the biotransformation of these molecules, its conformational mechanism and the molecular basis involved in the process are not fully understood. In this study, we used molecular dynamics and principal component analysis simulations for an in-depth analysis of the essential protein motions involved in the interaction of cytochrome 2A13 with its substrates. We also evaluated the interaction of these substrates with the amino acid residues in the binding pocket of cytochrome 2A13. Furthermore, we quantified the nature of these chemical interactions from free energy calculations using the Molecular Mechanics/Generalized Born Surface Area method. The ligands remained favorably oriented toward compound I (cytochrome P450 O═FeIV state), to undergo α-hydroxylation. The hydrogen bond with asparagine 297 was essential to maintaining the substrates in a favorable catalytic orientation. The plot of first principal motion vs second principal motion revealed that the enzyme's interaction with nicotine and NNK involved different conformational subgroups, whereas the conformational subgroups in the interaction with NNN are more similar. These results provide new mechanistic insights into the mode of interaction of the substrates with the active site of cytochrome 2A13, in the presence of compound I, which is essential for α-hydroxylation.
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Affiliation(s)
- Jorddy Neves Cruz
- Adolpho Ducke Laboratory , Emílio Goeldi Paraense Museum , Belém , Pará 66040-170, Brazil.,Laboratory of Agro-Industry , Embrapa Eastern Amazon , Belém , Pará 66040-170, Brazil
| | | | - Sebastião Gomes Silva
- Adolpho Ducke Laboratory , Emílio Goeldi Paraense Museum , Belém , Pará 66040-170, Brazil
| | | | | | - Anderson Henrique Lima E Lima
- Laboratory of Planning and Development of Pharmaceuticals , Federal University of Pará , Belém , Pará 70770-901, Brazil
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17
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Liu Y, Zhang D, Du J, Qin Y, Zhao Z, Shi Y, Mei S, Liu Y. Simultaneous determination of plasma nicotine and cotinine by UHPLC–MS/MS in C57BL/6 mice and its application in a pharmacokinetic study. Biomed Chromatogr 2019; 33:e4634. [PMID: 31257625 DOI: 10.1002/bmc.4634] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 06/20/2019] [Accepted: 06/26/2019] [Indexed: 01/27/2023]
Affiliation(s)
- Yang Liu
- Laboratory of Tissue Regeneration and Immunology and Department of Periodontics, Beijing Key Laboratory of Tooth Regeneration and Function ReconstructionSchool of Stomatology, Capital Medical University 4 Tiantanxili Beijing P. R. China
| | - Dongjie Zhang
- Department of Pharmacy, Beijing Tiantan HospitalCapital Medical University 119 Nansihuan West Road, Fengtai District Beijing P. R. China
| | - Juan Du
- Laboratory of Tissue Regeneration and Immunology and Department of Periodontics, Beijing Key Laboratory of Tooth Regeneration and Function ReconstructionSchool of Stomatology, Capital Medical University 4 Tiantanxili Beijing P. R. China
| | - Ying Qin
- Laboratory of Tissue Regeneration and Immunology and Department of Periodontics, Beijing Key Laboratory of Tooth Regeneration and Function ReconstructionSchool of Stomatology, Capital Medical University 4 Tiantanxili Beijing P. R. China
| | - Zhigang Zhao
- Department of Pharmacy, Beijing Tiantan HospitalCapital Medical University 119 Nansihuan West Road, Fengtai District Beijing P. R. China
- Department of Clinical Pharmacology, College of Pharmaceutical SciencesCapital Medical University Beijing P. R. China
| | - Yanjun Shi
- Department of Clinical Pharmacology, College of Pharmaceutical SciencesCapital Medical University Beijing P. R. China
- Department of Pharmacy, Beijing Tongren HospitalCapital Medical University Beijing P. R. China
| | - Shenghui Mei
- Department of Pharmacy, Beijing Tiantan HospitalCapital Medical University 119 Nansihuan West Road, Fengtai District Beijing P. R. China
- Department of Clinical Pharmacology, College of Pharmaceutical SciencesCapital Medical University Beijing P. R. China
| | - Yi Liu
- Laboratory of Tissue Regeneration and Immunology and Department of Periodontics, Beijing Key Laboratory of Tooth Regeneration and Function ReconstructionSchool of Stomatology, Capital Medical University 4 Tiantanxili Beijing P. R. China
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18
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Tsou HH, Ko HT, Chen CT, Wang TW, Lee CH, Liu TY, Wang HT. Betel quid containing safrole enhances metabolic activation of tobacco specific 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 251:13-21. [PMID: 31071628 DOI: 10.1016/j.envpol.2019.04.080] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 04/03/2019] [Accepted: 04/15/2019] [Indexed: 06/09/2023]
Abstract
Cigarette smoking (CS) and betel quid (BQ) chewing are two known risk factors that have synergistic potential for the enhancing the development of oral squamous cell carcinoma (OSCC) in Taiwan. Most mutagens and carcinogens are metabolically activated by cytochrome P450 (CYP450) to exert their mutagenicity or carcinogenicity. Previous studies have shown that metabolic activation of the tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), by CYP2A6 activity determines NNK-induced carcinogenesis. In addition, safrole affects cytochrome P450 activity in rodents. However, the effect of BQ safrole on the metabolism of tobacco-specific NNK and its carcinogenicity remains elusive. This study demonstrates that safrole (1 mg/kg/d) induced CYP2A6 activity, reduced urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) levels, and increased NNK-induced DNA damage, including N7-methylguanine, 8-OH-deoxyguanosine and DNA strand breaks in a Syrian golden hamster model. Furthermore, altered NNK metabolism and increased NNK-induced DNA damage were also observed in healthy subjects with CS and BQ chewing histories compared to healthy subjects with CS histories. In conclusion, BQ containing safrole induced tobacco-specific NNK metabolic activation, resulting in higher NNK-induced genotoxicity. This study provides valuable insight into the synergistic mechanisms of CS- and BQ-induced OSCC.
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Affiliation(s)
- Han-Hsing Tsou
- Institute of Environmental and Occupational Health Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Hsiao-Tung Ko
- Institute of Food Safety and Health Risk Assessment, National Yang-Ming University, Taipei, Taiwan
| | - Chia-Tzu Chen
- Institute of Environmental and Occupational Health Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Tse-Wen Wang
- Institute of Food Safety and Health Risk Assessment, National Yang-Ming University, Taipei, Taiwan
| | - Chien-Hung Lee
- Department of Public Health, College of Health Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan; Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Tsung-Yun Liu
- Institute of Environmental and Occupational Health Sciences, National Yang-Ming University, Taipei, Taiwan; Institute of Food Safety and Health Risk Assessment, National Yang-Ming University, Taipei, Taiwan
| | - Hsiang-Tsui Wang
- Department of Pharmacology, National Yang-Ming University, Taipei, Taiwan.
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Wei WJ, Qian HX, Wang WJ, Liao RZ. Computational Understanding of the Selectivities in Metalloenzymes. Front Chem 2018; 6:638. [PMID: 30622942 PMCID: PMC6308299 DOI: 10.3389/fchem.2018.00638] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 12/07/2018] [Indexed: 01/26/2023] Open
Abstract
Metalloenzymes catalyze many different types of biological reactions with high efficiency and remarkable selectivity. The quantum chemical cluster approach and the combined quantum mechanics/molecular mechanics methods have proven very successful in the elucidation of the reaction mechanism and rationalization of selectivities in enzymes. In this review, recent progress in the computational understanding of various selectivities including chemoselectivity, regioselectivity, and stereoselectivity, in metalloenzymes, is discussed.
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Affiliation(s)
| | | | | | - Rong-Zhen Liao
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, China
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20
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Ji M, Zhang Z, Li N, Xia R, Wang C, Yu Y, Yao S, Shen J, Wang SL. Identification of 5-hydroxymethylfurfural in cigarette smoke extract as a new substrate metabolically activated by human cytochrome P450 2A13. Toxicol Appl Pharmacol 2018; 359:108-117. [PMID: 30253172 DOI: 10.1016/j.taap.2018.09.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 09/12/2018] [Accepted: 09/21/2018] [Indexed: 02/06/2023]
Abstract
Cytochrome P450 2A13 (CYP2A13) is an extrahepatic enzyme mainly expressed in the human respiratory system and is reported to mediate tobacco-specific N-nitrosamines (TSNA) metabolism in cigarette smoke. This study aimed to identify other new substrates of CYP2A13 in cigarette smoke and their corresponding respiratory toxicity. Following separation by HPLC, GC-MS/MS, NMR and cytotoxicity assays in BEAS-2B cells stably expressing CYP2A13 (B-2A13), 5-Hydroxymethylfurfural (5-HMF) was screened and identified in the 4-5 min section of cigarette smoke extract (CSE). In vitro metabolism results showed that CYP2A13 mediated the fast clearance of 5-HMF and formed the metabolite 5-HMF acid (5-HMFA). CSE 5-HMF (CSE-5-HMF) showed cytotoxicity similar to that of standard 5-HMF in B-2A13 and B-2A5 cells, which was inhibited by 8-methoxypsoralen (8-MOP), a CYP enzyme inhibitor. Mouse CYP2A5, a homologous CYP enzyme to CYP2A13, shares many substrates with CYP2A13 in cigarette smoke. Thus, CYP2A5-/- mice were generated to explore the role of CYP2A5 in 5-HMF bioactivation. Compared with CYP2A5-/- mice, WT mice showed serious histological lung and nasal olfactory mucosa damage, as well as increased inflammatory cells and elevated TNF-α and IL-6 levels in bronchoalveolar lavage fluid. Besides, nasal microsomes undertook fast 5-HMFA formation in WT mice than that in CYP2A5-/- mice, which could be inhibited by 8-MOP. This study is the first to identify 5-HMF as a new toxic substrate of human CYP2A13 in cigarette smoke, it may play a potential role in cigarette smoke-induced respiratory injuries.
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Affiliation(s)
- Minghui Ji
- Key Lab of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, PR China; School of Nursing, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, PR China
| | - Zhan Zhang
- Key Lab of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, PR China; State Key Lab of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, PR China
| | - Na Li
- Key Lab of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, PR China
| | - Rong Xia
- Key Lab of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, PR China
| | - Chao Wang
- Key Lab of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, PR China; State Key Lab of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, PR China
| | - Yongquan Yu
- Key Lab of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, PR China; State Key Lab of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, PR China
| | - Shen Yao
- Key Lab of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, PR China
| | - Jiemiao Shen
- Key Lab of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, PR China
| | - Shou-Lin Wang
- Key Lab of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, PR China; State Key Lab of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, PR China.
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Kumondai M, Hosono H, Maekawa M, Yamaguchi H, Mano N, Oda A, Hirasawa N, Hiratsuka M. Functional characterization of 9 CYP2A13 allelic variants by assessment of nicotine C-oxidation and coumarin 7-hydroxylation. Drug Metab Pharmacokinet 2017; 33:82-89. [PMID: 29342418 DOI: 10.1016/j.dmpk.2017.11.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 11/01/2017] [Accepted: 11/13/2017] [Indexed: 10/18/2022]
Abstract
Cytochrome P450 2A13 (CYP2A13) is responsible for the metabolism of chemical compounds such as nicotine, coumarin, and tobacco-specific nitrosamine. Several of these compounds have been recognized as procarcinogens activated by CYP2A13. We recently showed that CYP2A13*2 contributes to inter-individual variations observed in bladder cancer susceptibility because CYP2A13*2 might cause a decrease in enzymatic activity. Other CYP2A13 allelic variants may also affect cancer susceptibility. In this study, we performed an in vitro analysis of the wild-type enzyme (CYP2A13.1) and 8 CYP2A13 allelic variants, using nicotine and coumarin as representative CYP2A13 substrates. These CYP2A13 variant proteins were heterologously expressed in 293FT cells, and the kinetic parameters of nicotine C-oxidation and coumarin 7-hydroxylation were estimated. The quantities of CYP2A13 holoenzymes in microsomal fractions extracted from 293FT cells were determined by measuring reduced carbon monoxide-difference spectra. The kinetic parameters for CYP2A13.3, CYP2A13.4, and CYP2A13.10 could not be determined because of low metabolite concentrations. Five other CYP2A13 variants (CYP2A13.2, CYP2A13.5, CYP2A13.6, CYP2A13.8, and CYP2A13.9) showed markedly reduced enzymatic activity toward both substrates. These findings provide insights into the mechanism underlying inter-individual differences observed in genotoxicity and cancer susceptibility.
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Affiliation(s)
- Masaki Kumondai
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, 980-8578, Japan
| | - Hiroki Hosono
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, 980-8578, Japan
| | - Masamitsu Maekawa
- Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, 980-8574, Japan
| | - Hiroaki Yamaguchi
- Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, 980-8574, Japan
| | - Nariyasu Mano
- Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, 980-8574, Japan
| | - Akifumi Oda
- Faculty of Pharmacy, Meijo University, Nagoya, 468-8503, Japan
| | - Noriyasu Hirasawa
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, 980-8578, Japan
| | - Masahiro Hiratsuka
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, 980-8578, Japan; Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, 980-8574, Japan; Tohoku Medical Megabank Organization, Tohoku University, Sendai, 980-8575, Japan.
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22
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Ji M, Zhang Y, Li N, Wang C, Xia R, Zhang Z, Wang SL. Nicotine Component of Cigarette Smoke Extract (CSE) Decreases the Cytotoxicity of CSE in BEAS-2B Cells Stably Expressing Human Cytochrome P450 2A13. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:ijerph14101221. [PMID: 29027939 PMCID: PMC5664722 DOI: 10.3390/ijerph14101221] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Revised: 10/06/2017] [Accepted: 10/09/2017] [Indexed: 11/16/2022]
Abstract
Cytochrome P450 2A13 (CYP2A13), an extrahepatic enzyme mainly expressed in the human respiratory system, has been reported to mediate the metabolism and toxicity of cigarette smoke. We previously found that nicotine inhibited 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) metabolism by CYP2A13, but its influence on other components of cigarette smoke remains unclear. The nicotine component of cigarette smoke extract (CSE) was separated, purified, and identified using high-performance liquid chromatography (HPLC) and ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS), splitting CSE into a nicotine section (CSE-N) and nicotine-free section (CSE-O). Cell viability and apoptosis by Cell Counting Kit-8 (CCK-8) and flow cytometry assays were conducted on immortalized human bronchial epithelial (BEAS-2B) cells stably expressing CYP2A13 (B-2A13) or vector (B-V), respectively. Interestingly, CSE and CSE-O were toxic to BEAS-2B cells whereas CSE-N showed less cytotoxicity. CSE-O was more toxic to B-2A13 cells than to B-V cells (IC50 of 2.49% vs. 7.06%), which was flatted by 8-methoxypsoralen (8-MOP), a CYP inhibitor. CSE-O rather than CSE or CSE-N increased apoptosis of B-2A13 cells rather than B-V cells. Accordingly, compared to CSE-N and CSE, CSE-O significantly changed the expression of three pairs of pro- and anti-apoptotic proteins, Bcl-2 Associated X Protein/B cell lymphoma-2 (Bax/Bcl-2), Cleaved Poly (Adenosine Diphosphate-Ribose) Polymerase/Poly (Adenosine Diphosphate-Ribose) Polymerase (C-PARP/PARP), and C-caspase-3/caspase-3, in B-2A13 cells. In addition, recombination of CSE-N and CSE-O (CSE-O/N) showed similar cytotoxicity and apoptosis to the original CSE. These results demonstrate that the nicotine component decreases the metabolic activation of CYP2A13 to CSE and aids in understanding the critical role of CYP2A13 in human respiratory diseases caused by cigarette smoking.
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Affiliation(s)
- Minghui Ji
- Key Lab of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, China.
- State Key Lab of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, China.
- School of Nursing, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, China.
| | - Yudong Zhang
- Key Lab of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, China.
| | - Na Li
- Key Lab of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, China.
| | - Chao Wang
- Key Lab of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, China.
- State Key Lab of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, China.
| | - Rong Xia
- Key Lab of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, China.
| | - Zhan Zhang
- Key Lab of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, China.
- State Key Lab of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, China.
| | - Shou-Lin Wang
- Key Lab of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, China.
- State Key Lab of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, China.
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23
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Kaisar MA, Kallem RR, Sajja RK, Sifat AE, Cucullo L. A convenient UHPLC-MS/MS method for routine monitoring of plasma and brain levels of nicotine and cotinine as a tool to validate newly developed preclinical smoking model in mouse. BMC Neurosci 2017; 18:71. [PMID: 29020944 PMCID: PMC5637319 DOI: 10.1186/s12868-017-0389-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 10/05/2017] [Indexed: 12/29/2022] Open
Abstract
Background A sensitive, rapid and selective UHPLC–MS/MS method has been developed and validated for the quantification of Nicotine (NT) and Cotinine (CN) using Continine-d3 as internal standard (IS) as per FDA guidelines. Sample preparation involved simple protein precipitation of 20 µL mouse plasma or brain homogenate using acetonitrile at 1:8 ratio. Mass Spectrometer was operated in positive polarity under the multiple reaction-monitoring mode using electro spray ionization technique and the transitions of m/z 163.2 → 132.1, 177.2 → 98.0 and 180.2 → 101.2 were used to measure the NT, CN and IS, respectively. The elution of NT, CN and IS are at 1.89, 1.77 and 1.76 min, respectively. This was achieved with a gradient mobile phase consisting of 5 mM ammonium bicarbonate, acetonitrile and methanol (3:1, v/v) at a flow rate of 0.3 mL/min on a Kinetex EVO C18 column. The method was validated with a lower limit of quantitation 3.0 ng/mL in mouse plasma and brain for both the analytes. Results A linear response function was established for the range of concentrations 3–200 (r > 0.995) for NT and 3–600 ng/mL (r > 0.995) for CN. The intra- and inter-day precision values met the acceptance criteria. NT and CN are stable in the battery of stability studies viz., stock solution, bench-top and auto-sampler. Conclusion This method was successfully utilized to validate a newly developed preclinical smoking model in mice.
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Affiliation(s)
- Mohammad A Kaisar
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, 1300 S. Coulter Street, Amarillo, TX, 79106, USA
| | - Raja Reddy Kallem
- Office of Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, TX, 79106, USA
| | - Ravi K Sajja
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, 1300 S. Coulter Street, Amarillo, TX, 79106, USA
| | - Ali Ehsan Sifat
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, 1300 S. Coulter Street, Amarillo, TX, 79106, USA
| | - Luca Cucullo
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, 1300 S. Coulter Street, Amarillo, TX, 79106, USA. .,Center for Blood Brain Barrier Research, Texas Tech University Health Sciences Center, Amarillo, TX, 79106, USA.
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Wang Q, Kuang Y, He J, Li K, Song W, Jin H, Qiao X, Ye M. The prenylated phenolic natural product isoglycycoumarin is a highly selective probe for human cytochrome P450 2A6. Eur J Pharm Sci 2017; 109:472-479. [PMID: 28867491 DOI: 10.1016/j.ejps.2017.08.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 07/07/2017] [Accepted: 08/30/2017] [Indexed: 10/18/2022]
Abstract
Prenylated phenolic compounds are an important class of bioactive natural products. One major in vivo metabolic pathway of these compounds is hydroxylation at terminal methyl of the isoprenyl group. This study aims to identify the P450 isozyme catalyzing this metabolic reaction. In human liver microsomes, 16 out of 24 screened compounds could be metabolized into their hydroxylated derivatives. Chemical inhibition assays using 11 isozyme specific inhibitors indicated the hydroxylation reactions of 12 compounds were primarily catalyzed by cytochrome P450 2A6 (CYP2A6). In particular, CYP2A6 was the major enzyme participating in the metabolism of isoglycycoumarin (IGCM). The product of IGCM was obtained and identified as licopyranocoumarin (4″-hydroxyl isoglycycoumarin) using NMR spectroscopic analysis. The Km values for human liver microsomes and recombinant human CYP2A6 were 7.98 and 10.14μM, respectively. According to molecular docking analysis, the catalytic mechanism may involve cyclized isoprenyl group of IGCM entering the active cavity of CYP2A6. These results demonstrate that IGCM could serve as an ideal isozyme selective probe to evaluate CYP2A6 activities.
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Affiliation(s)
- Qi Wang
- Department of Medicinal Chemistry and Natural Medicine Chemistry, College of Pharmacy, Harbin Medical University, Baojian Road 157, Nangang District, Harbin 150081, China; State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China
| | - Yi Kuang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China
| | - Junbin He
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China
| | - Kai Li
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China
| | - Wei Song
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China
| | - Hongwei Jin
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China
| | - Xue Qiao
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China.
| | - Min Ye
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China.
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25
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Lefever TW, Lee YO, Kovach AL, Silinski MA, Marusich JA, Thomas BF, Wiley JL. Delivery of nicotine aerosol to mice via a modified electronic cigarette device. Drug Alcohol Depend 2017; 172:80-87. [PMID: 28157590 PMCID: PMC5327853 DOI: 10.1016/j.drugalcdep.2016.12.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 11/21/2016] [Accepted: 12/04/2016] [Indexed: 01/05/2023]
Abstract
BACKGROUND Although both men and women use e-cigarettes, most preclinical nicotine research has focused on its effects in male rodents following injection. The goals of the present study were to develop an effective e-cigarette nicotine delivery system, to compare results to those obtained after subcutaneous (s.c.) injection, and to examine sex differences in the model. METHODS Hypothermia and locomotor suppression were assessed following aerosol exposure or s.c. injection with nicotine in female and male mice. Subsequently, plasma and brain concentrations of nicotine and cotinine were measured. RESULTS Passive exposure to nicotine aerosol produced concentration-dependent and mecamylamine reversible hypothermic and locomotor suppressant effects in female and male mice, as did s.c. nicotine injection. In plasma and brain, nicotine and cotinine concentrations showed dose/concentration-dependent increases in both sexes following each route of administration. Sex differences in nicotine-induced hypothermia were dependent upon route of administration, with females showing greater hypothermia following aerosol exposure and males showing greater hypothermia following injection. In contrast, when they occurred, sex differences in nicotine and cotinine levels in brain and plasma consistently showed greater concentrations in females than males, regardless of route of administration. DISCUSSION In summary, the e-cigarette exposure device described herein was used successfully to deliver pharmacologically active doses of nicotine to female and male mice. Further, plasma nicotine concentrations following exposure were similar to those after s.c. injection with nicotine and within the range observed in human smokers. Future research on vaped products can be strengthened by inclusion of translationally relevant routes of administration.
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Affiliation(s)
- Timothy W. Lefever
- RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709
| | - Youn O.K. Lee
- RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709
| | | | | | - Julie A. Marusich
- RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709
| | - Brian F. Thomas
- RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709
| | - Jenny L. Wiley
- RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709
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26
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Abstract
Nicotine is the primary addictive agent in tobacco, and P450 2A6 (gene name: CYP2A6) is the primary catalyst of nicotine metabolism. It was proposed more than 20 years ago that individuals who metabolize nicotine poorly would smoke less, either fewer cigarettes per day or less intensely per cigarette, compared to smokers who metabolize nicotine more efficiently. These poor metabolizers would then be less likely to develop lung cancer due to their lower exposure to the many carcinogens delivered with nicotine in each puff of smoke. Numerous studies have reported that smokers who carry reduced activity or null CYP2A6 alleles do smoke less. Yet only in Asian populations, both Japanese and Chinese, which have a high prevalence of genetic variants, has a link between CYP2A6, smoking dose, and lung cancer been established. In other ethnic groups, it has been challenging to confirm a direct link between P450 2A6-mediated nicotine metabolism and the risk of lung cancer. This challenge is due in part to the difficulty in accurately quantifying smoking dose and accurately predicting or measuring P450 2A6-mediated nicotine metabolism. Biomarkers of nicotine metabolism and smoking exposure, including the ratio of trans-3-hydroxycotine to cotinine, a measure of P450 2A6 activity and plasma cotinine, or urinary total nicotine equivalents (the sum of nicotine and six metabolites) as measures of exposure are useful for addressing this challenge. However, to take full advantage of these biomarkers in the study of ethnic/racial differences in the risk of lung cancer requires the complete characterization of nicotine metabolism across ethnic/racial groups. Variation in metabolism pathways, other than those catalyzed by P450 2A6, can impact biomarkers of both nicotine metabolism and dose. This is clearly important for smokers with low levels of UGT2B10-catalyzed nicotine and cotinine glucuronidation because the UGT2B10 genotype influences plasma cotinine levels. Cotinine is not glucuronidated in 15% of African American smokers (compared to 1% of Whites) due to the prevalence of a UGT2B10 splice variant. This variant contributes significantly to the higher plasma cotinine levels per cigarette in this group and may also influence the accuracy of the 3HCOT to cotinine ratio as a measure of P450 2A6 activity.
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Affiliation(s)
- Sharon E. Murphy
- Department of Biochemistry Molecular Biology and Biophysics and Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455
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27
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Budzynska B, Skalicka-Wozniak K, Kruk-Slomka M, Wydrzynska-Kuzma M, Biala G. In vivo modulation of the behavioral effects of nicotine by the coumarins xanthotoxin, bergapten, and umbelliferone. Psychopharmacology (Berl) 2016; 233:2289-300. [PMID: 27080866 PMCID: PMC4873531 DOI: 10.1007/s00213-016-4279-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 03/14/2016] [Indexed: 12/14/2022]
Abstract
RATIONALE Nicotine, a dominant alkaloid found in tobacco, is responsible for physical dependence, as well as addiction to cigarette smoking; consequently, smoking cessation is a very difficult process. Hepatic cytochrome P-450 2A6 (CYP2A6) is involved in the 70-80 % of the initial metabolism of nicotine and its co-metabolites. As this metabolism is slowed by inhibitors of CYP2A6, this kind of enzymatic inhibition has been proposed as a novel target for smoking cessation. OBJECTIVES Nicotine administered alone improved memory acquisition and consolidation as well as exerted antidepressive activity in animal models. These effects persist for 24 h. However, they are completely extinguished 48 h after administration. METHODS To investigate if the coumarins prolong the behavioral effects of nicotine, the forced swimming test (FST)-animal models of depression, and passive avoidance (PA) test-memory and learning paradigm were used. RESULTS This study revealed that three CYP2A6 inhibitors: two furanocoumarins, xanthotoxin (15 mg/kg) and bergapten (25 mg/kg), and the simple coumarin umbelliferone (25 mg/kg), prolonged the antidepressive and procognitive effects of nicotine. CONCLUSIONS These natural products may offer a new approach to the treatment of nicotinism as antidepressant and memory improvement actions are one of the main factors of nicotine dependence.
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Affiliation(s)
- Barbara Budzynska
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Lublin, Poland.
| | - Krystyna Skalicka-Wozniak
- />Department of Pharmacognosy with Medicinal Plants Unit, Medical University of Lublin, Lublin, Poland
| | - Marta Kruk-Slomka
- />Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Lublin, Poland
| | | | - Grazyna Biala
- />Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Lublin, Poland
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28
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Shah MB, Wilderman PR, Liu J, Jang HH, Zhang Q, Stout CD, Halpert JR. Structural and biophysical characterization of human cytochromes P450 2B6 and 2A6 bound to volatile hydrocarbons: analysis and comparison. Mol Pharmacol 2015; 87:649-59. [PMID: 25585967 PMCID: PMC4366795 DOI: 10.1124/mol.114.097014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 01/12/2015] [Indexed: 11/22/2022] Open
Abstract
X-ray crystal structures of complexes of cytochromes CYP2B6 and CYP2A6 with the monoterpene sabinene revealed two distinct binding modes in the active sites. In CYP2B6, sabinene positioned itself with the putative oxidation site located closer to the heme iron. In contrast, sabinene was found in an alternate conformation in the more compact CYP2A6, where the larger hydrophobic side chains resulted in a significantly reduced active-site cavity. Furthermore, results from isothermal titration calorimetry indicated a much more substantial contribution of favorable enthalpy to sabinene binding to CYP2B6 as opposed to CYP2A6, consistent with the previous observations with (+)-α-pinene. Structural analysis of CYP2B6 complexes with sabinene and the structurally similar (3)-carene and comparison with previously solved structures revealed how the movement of the F206 side chain influences the volume of the binding pocket. In addition, retrospective analysis of prior structures revealed that ligands containing -Cl and -NH functional groups adopted a distinct orientation in the CYP2B active site compared with other ligands. This binding mode may reflect the formation of Cl-π or NH-π bonds with aromatic rings in the active site, which serve as important contributors to protein-ligand binding affinity and specificity. Overall, the findings from multiple techniques illustrate how drugs metabolizing CYP2B6 and CYP2A6 handle a common hydrocarbon found in the environment. The study also provides insight into the role of specific functional groups of the ligand that may influence the binding to CYP2B6.
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Affiliation(s)
- Manish B Shah
- Department of Pharmaceutical Sciences, The University of Connecticut, Storrs, Connecticut (M.B.S., P.R.W., J.L., J.R.H.); School of Biological Sciences and Technology, Chonnam National University, Gwangju, Republic of Korea (H.-H.J.); and Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California (Q.Z., C.D.S.)
| | - P Ross Wilderman
- Department of Pharmaceutical Sciences, The University of Connecticut, Storrs, Connecticut (M.B.S., P.R.W., J.L., J.R.H.); School of Biological Sciences and Technology, Chonnam National University, Gwangju, Republic of Korea (H.-H.J.); and Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California (Q.Z., C.D.S.)
| | - Jingbao Liu
- Department of Pharmaceutical Sciences, The University of Connecticut, Storrs, Connecticut (M.B.S., P.R.W., J.L., J.R.H.); School of Biological Sciences and Technology, Chonnam National University, Gwangju, Republic of Korea (H.-H.J.); and Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California (Q.Z., C.D.S.)
| | - Hyun-Hee Jang
- Department of Pharmaceutical Sciences, The University of Connecticut, Storrs, Connecticut (M.B.S., P.R.W., J.L., J.R.H.); School of Biological Sciences and Technology, Chonnam National University, Gwangju, Republic of Korea (H.-H.J.); and Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California (Q.Z., C.D.S.)
| | - Qinghai Zhang
- Department of Pharmaceutical Sciences, The University of Connecticut, Storrs, Connecticut (M.B.S., P.R.W., J.L., J.R.H.); School of Biological Sciences and Technology, Chonnam National University, Gwangju, Republic of Korea (H.-H.J.); and Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California (Q.Z., C.D.S.)
| | - C David Stout
- Department of Pharmaceutical Sciences, The University of Connecticut, Storrs, Connecticut (M.B.S., P.R.W., J.L., J.R.H.); School of Biological Sciences and Technology, Chonnam National University, Gwangju, Republic of Korea (H.-H.J.); and Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California (Q.Z., C.D.S.)
| | - James R Halpert
- Department of Pharmaceutical Sciences, The University of Connecticut, Storrs, Connecticut (M.B.S., P.R.W., J.L., J.R.H.); School of Biological Sciences and Technology, Chonnam National University, Gwangju, Republic of Korea (H.-H.J.); and Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California (Q.Z., C.D.S.)
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29
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Patel YM, Stram DO, Wilkens LR, Park SSL, Henderson BE, Le Marchand L, Haiman CA, Murphy SE. The contribution of common genetic variation to nicotine and cotinine glucuronidation in multiple ethnic/racial populations. Cancer Epidemiol Biomarkers Prev 2014; 24:119-27. [PMID: 25293881 DOI: 10.1158/1055-9965.epi-14-0815] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND The lung cancer risk of smokers varies by race/ethnicity even after adjustment for smoking. Evaluating the role of genetics in nicotine metabolism is likely important in understanding these differences, as disparities in risk may be related to differences in nicotine dose and metabolism. METHODS We conducted a genome-wide association study in search of common genetic variants that predict nicotine and cotinine glucuronidation in a sample of 2,239 smokers (437 European Americans, 364 African Americans, 453 Latinos, 674 Japanese Americans, and 311 Native Hawaiians) in the Multiethnic Cohort Study. Urinary concentration of nicotine and its metabolites were determined. RESULTS Among 11,892,802 variants analyzed, 1,241 were strongly associated with cotinine glucuronidation, 490 of which were also associated with nicotine glucuronidation (P < 5×10(-8)). The vast majority were within chromosomal region 4q13, near UGT2B10. Fifteen independent and globally significant SNPs explained 33.2% of the variation in cotinine glucuronidation, ranging from 55% for African Americans to 19% for Japanese Americans. The strongest single SNP association was for rs115765562 (P = 1.60 × 10(-155)). This SNP is highly correlated with a UGT2B10 splice site variant, rs116294140, which together with rs6175900 (Asp67Tyr) explains 24.3% of the variation. The top SNP for nicotine glucuronidation (rs116224959, P = 2.56 × 10(-43)) was in high LD (r(2) = 0.99) with rs115765562. CONCLUSIONS Genetic variation in UGT2B10 contributes significantly to nicotine and cotinine glucuronidation but not to nicotine dose. IMPACT The contribution of genetic variation to nicotine and cotinine glucuronidation varies significantly by racial/ethnic group, but is unlikely to contribute directly to lung cancer risk.
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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
| | - Daniel O Stram
- Department of Preventive Medicine and Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Lynne R Wilkens
- Cancer Research Center of Hawaii, University of Hawaii, Honolulu, Hawaii
| | - Sung-Shim L Park
- Department of Preventive Medicine and Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Brian E Henderson
- Department of Preventive Medicine and Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Loic Le Marchand
- Cancer Research Center of Hawaii, University of Hawaii, Honolulu, Hawaii
| | - Christopher A Haiman
- Department of Preventive Medicine and Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Sharon E Murphy
- Department of Biochemistry, Molecular Biology, and Biophysics and Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota.
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Murphy SE, Park SSL, Thompson EF, Wilkens LR, Patel Y, Stram DO, Le Marchand L. Nicotine N-glucuronidation relative to N-oxidation and C-oxidation and UGT2B10 genotype in five ethnic/racial groups. Carcinogenesis 2014; 35:2526-33. [PMID: 25233931 DOI: 10.1093/carcin/bgu191] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Nicotine metabolism influences smoking behavior and differences in metabolism probably contribute to ethnic variability in lung cancer risk. We report here on the proportion of nicotine metabolism by cytochrome P450 2A6-catalyzed C-oxidation, UDP-glucuronosyl transferase 2B10 (UGT2B10)-catalyzed N-glucuronidation and flavin monooxygenase 3-catalyzed N-oxidation in five ethnic/racial groups and the role of UGT2B10 genotype on the metabolic patterns observed. Nicotine and its metabolites were quantified in urine from African American (AA, n = 364), Native Hawaiian (NH, n = 311), White (n = 437), Latino (LA, n = 453) and Japanese American (JA, n = 674) smokers. Total nicotine equivalents, the sum of nicotine and six metabolites, and nicotine metabolism phenotypes were calculated. The relationship of UGT2B10 genotype to nicotine metabolic pathways was determined for each group; geometric means were computed and adjusted for age, sex, creatinine, and body mass index. Nicotine metabolism patterns were unique across the groups, C-oxidation was lowest in JA and NH (P < 0.0001), and N-glucuronidation lowest in AA (P < 0.0001). There was no difference in C-oxidation among Whites and AA and LA. Nicotine and cotinine glucuronide ratios were 2- and 3-fold lower in AA compared with Whites. Two UGT variants, a missense mutation (Asp67Tyr, rs61750900) and a splice variant (rs116294140) accounted for 33% of the variation in glucuronidation. In AA, the splice variant accounted for the majority of the reduced nicotine glucuronidation. UGT2B10 variant allele carriers had increased levels of C-oxidation (P = 0.0099). Our data indicate that the relative importance of nicotine metabolic pathways varies by ethnicity, and all pathways should be considered when characterizing the role of nicotine metabolism on smoking behavior and cancer risk.
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Affiliation(s)
- Sharon E Murphy
- Department of Biochemistry Molecular Biology and Biophysics and Masonic Cancer Center, University of Minnesota, 2-127 CCRB, 2231 6th Street SE, Minneapolis, MN 55455, USA, Department of Preventive Medicine, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA and Cancer Research Center of Hawai'i, University of Hawai'i, Honolulu, HI 96813, USA
| | - Sung-Shim L Park
- Department of Preventive Medicine, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA and
| | - Elizabeth F Thompson
- Department of Biochemistry Molecular Biology and Biophysics and Masonic Cancer Center, University of Minnesota, 2-127 CCRB, 2231 6th Street SE, Minneapolis, MN 55455, USA, Department of Preventive Medicine, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA and Cancer Research Center of Hawai'i, University of Hawai'i, Honolulu, HI 96813, USA
| | - Lynne R Wilkens
- Cancer Research Center of Hawai'i, University of Hawai'i, Honolulu, HI 96813, USA
| | - Yesha Patel
- Department of Preventive Medicine, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA and
| | - Daniel O Stram
- Department of Preventive Medicine, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA and
| | - Loic Le Marchand
- Cancer Research Center of Hawai'i, University of Hawai'i, Honolulu, HI 96813, USA
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Bagdas D, Muldoon PP, Zhu AZX, Tyndale RF, Damaj MI. Effects of methoxsalen, a CYP2A5/6 inhibitor, on nicotine dependence behaviors in mice. Neuropharmacology 2014; 85:67-72. [PMID: 24859605 DOI: 10.1016/j.neuropharm.2014.05.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 04/22/2014] [Accepted: 05/02/2014] [Indexed: 11/15/2022]
Abstract
Metabolism of nicotine to inactive cotinine by hepatic enzyme CYP2A6 is the principal pathway by which active nicotine is removed from circulation. We therefore hypothesized that inhibition of mouse CYP2A5, the ortolog of human CYP2A6, by methoxsalen (8-methoxypsoralen) alter dependence-related behaviors of nicotine in the mouse. Conditioned place preference (CPP) test was used to assess the appetitive reward-like properties and precipitated nicotine withdrawal to assess physical (somatic and hyperalgesia) and affective (anxiety-related behaviors) measures. The nicotine plasma levels were also measured with or without methoxsalen pretreatment. Methoxsalen (15 and 30 mg/kg, intraperitoneally) pretreatment enhanced nicotine-induced preference in mice (p<0.05). However, there was a lack of enhancement of nicotine in the CPP test after the highest dose of the CYP-2A5 inhibitor. Similarly to the CPP results, repeated administration of methoxsalen increased the intensity of mecamylamine-precipitated withdrawal signs. The potentiation of nicotine preference and withdrawal intensity by methoxsalen was accompanied by significant increase in nicotine plasma levels in mice (p<0.05). Finally, methoxsalen enhanced the ability of a very low dose of nicotine (0.05 mg/kg) to reverse withdrawal signs in mice undergoing spontaneous withdrawal after chronic nicotine infusion (p<0.05). In conclusion, inhibition of nicotine metabolism by methoxsalen alters the behavioral effects of nicotine in the mouse. Combining CYP2A6 inhibitors with low dose nicotine replacement therapies may have a beneficial role in smoking cessation because it will decrease the drug elimination rate and maintain plasma and brain nicotine levels.
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Affiliation(s)
- Deniz Bagdas
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA 23298-0613, USA; Experimental Animals Breeding and Research Center, Faculty of Medicine, Uludag University, Bursa 16059, Turkey.
| | - Pretal P Muldoon
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA 23298-0613, USA
| | - Andy Z X Zhu
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Department of Pharmacology and Toxicology, and Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Rachel F Tyndale
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Department of Pharmacology and Toxicology, and Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - M Imad Damaj
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA 23298-0613, USA
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Castrignanò S, Ortolani A, Sadeghi SJ, Di Nardo G, Allegra P, Gilardi G. Electrochemical detection of human cytochrome P450 2A6 inhibition: a step toward reducing dependence on smoking. Anal Chem 2014; 86:2760-6. [PMID: 24527722 DOI: 10.1021/ac4041839] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Inhibition of human cytochrome P450 2A6 has been demonstrated to play an important role in nicotine metabolism and consequent smoking habits. Here, the "molecular Lego" approach was used to achieve the first reported electrochemical signal of human CYP2A6 and to improve its catalytic efficiency on electrode surfaces. The enzyme was fused at the genetic level to flavodoxin from Desulfovibrio vulgaris (FLD) to create the chimeric CYP2A6-FLD. Electrochemical characterization by cyclic voltammetry shows clearly defined redox transitions of the haem domain in both CYP2A6 and CYP2A6-FLD. Electrocatalysis experiments using coumarin as substrate followed by fluorimetric quantification of the product were performed with immobilized CYP2A6 and CYP2A6-FLD. Comparison of the kinetic parameters showed that coumarin catalysis was carried out with a higher efficiency by the immobilized CYP2A6-FLD, with a calculated kcat value significantly higher (P < 0.005) than that of CYP2A6, whereas the affinity for the substrate (KM) remained unaltered. The chimeric system was also successfully used to demonstrate the inhibition of the electrochemical activity of the immobilized CYP2A6-FLD, toward both coumarin and nicotine substrates, by tranylcypromine, a potent and selective CYP2A6 inhibitor. This work shows that CYP2A6 turnover efficiency is improved when the protein is linked to the FLD redox module, and this strategy can be utilized for the development of new clinically relevant biotechnological approaches suitable for deciphering the metabolic implications of CYP2A6 polymorphism and for the screening of CYP2A6 substrates and inhibitors.
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Affiliation(s)
- Silvia Castrignanò
- Department of Life Sciences and Systems Biology, University of Torino , 10123 Torino, Italy
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33
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Ande A, McArthur C, Kumar A, Kumar S. Tobacco smoking effect on HIV-1 pathogenesis: role of cytochrome P450 isozymes. Expert Opin Drug Metab Toxicol 2013; 9:1453-64. [PMID: 23822755 PMCID: PMC4007120 DOI: 10.1517/17425255.2013.816285] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
INTRODUCTION Tobacco smoking is highly prevalent among the HIV-1-infected population. In addition to diminished immune response, smoking has been shown to increase HIV-1 replication and decrease response to antiretroviral therapy, perhaps through drug-drug interaction. However, the mechanism by which tobacco/nicotine increases HIV-1 replication and mediates drug-drug interaction is poorly understood. AREAS COVERED In this review, the authors discuss the effects of smoking on HIV-1 pathogenesis. Since they propose a role for the cytochrome P450 (CYP) pathway in smoking-mediated HIV-1 pathogenesis, the authors briefly converse the role of CYP enzymes in tobacco-mediated oxidative stress and toxicity. Finally, the authors focus on the role of CYP enzymes, especially CYP2A6, in tobacco/nicotine metabolism and oxidative stress in HIV-1 model systems monocytes/macrophages, lymphocytes, astrocytes and neurons, which may be responsible for HIV-1 pathogenesis. EXPERT OPINION Recent findings suggest that CYP-mediated oxidative stress is a novel pathway that may be involved in smoking-mediated HIV-1 pathogenesis, including HIV-1 replication and drug-drug interaction. Thus, CYP and CYP-associated oxidative stress pathways may be potential targets to develop novel pharmaceuticals for HIV-1-infected smokers. Since HIV-1/TB co-infections are common, future study involving interactions between antiretroviral and antituberculosis drugs that involve CYP pathways would also help treat HIV-1/TB co-infected smokers effectively.
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Affiliation(s)
- Anusha Ande
- University of Missouri Kansas City, School of Pharmacy, Division of Pharmacology & Toxicology, Kansas City, MO 64108, USA
| | - Carole McArthur
- Professor, University of Missouri Kansas City, School of Dentistry, Department of Oral Biology, Kansas City, MO 64108, USA
| | - Anil Kumar
- Professor and Chair, University of Missouri Kansas City, School of Pharmacy, Division of Pharmacology & Toxicology, Kansas City, MO 64108, USA
| | - Santosh Kumar
- Assistant Professor, University of Missouri Kansas City, School of Pharmacy, Division of Pharmacology & Toxicology, 2464 Charlotte St. Kansas City, MO 64108, USA Tel: +1 816 235 5494 (Off); Fax: +1 816 235 1776;
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Alsharari SD, Siu ECK, Tyndale RF, Damaj MI. Pharmacokinetic and pharmacodynamics studies of nicotine after oral administration in mice: effects of methoxsalen, a CYP2A5/6 inhibitor. Nicotine Tob Res 2013; 16:18-25. [PMID: 23884323 DOI: 10.1093/ntr/ntt105] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
INTRODUCTION The use of novel oral nicotine delivery devices and compositions for human consumption and for animal research studies has been increasing in the last several years. METHODS Studies were undertaken to examine whether the systemic administration of methoxsalen, an inhibitor of human CYP2A6 and mouse CYP2A5, would modulate nicotine pharmacokinetics and pharmacological effects (antinociception in the tail-flick, and hot-plate tests, and hypothermia) in male ICR mouse after acute oral nicotine administration. RESULTS Administration of intra peritoneal (ip) methoxsalen significantly increased nicotine's Cmax, prolonged the plasma half-life (fourfold decrease) of nicotine, and increased its area under the curve (AUC) compared with ip vehicle treatment. Methoxsalen pretreatment prolonged the duration of nicotine-induced antinociception and hypothermia (15mg/kg, po) for periods up to 6- and 24-hr postnicotine administration, respectively. Additionally, methoxsalen potentiated nicotine-induced antinociception and hypothermia as evidenced by leftward shifts in nicotine's dose-response curve. Furthermore, this prolongation of nicotine's effects after methoxsalen was associated with a parallel prolongation of nicotine plasma levels in mice. These data strongly suggest that variation in the rates of nicotine metabolic inactivation substantially alter pharmacological effects of nicotine given orally. CONCLUSION We have shown that the pharmacological effects of inhibiting nicotine's metabolism after oral administration in mice are profound. Our results suggest that inhibiting nicotine metabolism can be used to dramatically enhance nicotine's bioavailability and its resulting pharmacology, which further supports this inhibitory approach for clinical development of an oral nicotine replacement therapy.
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Affiliation(s)
- Shakir D Alsharari
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Kingdom of Saudi Arabia
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35
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Li D, Huang X, Lin J, Zhan CG. Catalytic mechanism of cytochrome P450 for N-methylhydroxylation of nicotine: reaction pathways and regioselectivity of the enzymatic nicotine oxidation. Dalton Trans 2013; 42:3812-20. [PMID: 23303461 DOI: 10.1039/c2dt32106h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The fundamental reaction mechanism of cytochrome P450 2A6 (CYP2A6)-catalyzed N-methylhydroxylation of (S)-(-)-nicotine and the free energy profile have been studied by performing pseudobond first-principles quantum mechanical/molecular mechanical (QM/MM) reaction-coordinate calculations. In the CYP2A6-(S)-(-)-nicotine binding structures that allow for 5'-hydroxylation, the N-methyl group is also sufficiently close to the oxygen of Cpd I for the N-methylhydroxylation reaction to occur. It has been demonstrated that the CYP2A6-catalyzed N-methylhydroxylation reaction is a concerted process involving a hydrogen-transfer transition state on both the quartet and the doublet states. The N-methylhydroxylation reaction proceeds mainly in the doublet state, since the free energy barriers on the doublet state are lower than the corresponding ones on the quartet state. The calculated free energy barriers indicate that (S)-(-)-nicotine oxidation catalyzed by CYP2A6 proceeds with a high regioselective abstraction of the hydrogen at the 5'-position, rather than the hydrogen at the N-methyl group. The predicted regioselectivity of 93% is in agreement with the most recent experimentally reported regioselectivity of 95%. The binding mode of (S)-(-)-nicotine in the active site of CYP2A6 is an important determinant for the stereoselectivity of nicotine (S)-(-)-oxidation, whereas the regioselectivity of (S)-(-)-nicotine oxidation is determined mainly by the free energy barrier difference between the 5'-hydroxylation and N-methylhydroxylation reactions.
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Affiliation(s)
- Dongmei Li
- College of Pharmacy, State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071, China.
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36
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von Weymarn LB, Retzlaff C, Murphy SE. CYP2A6- and CYP2A13-catalyzed metabolism of the nicotine Δ5'(1')iminium ion. J Pharmacol Exp Ther 2012; 343:307-15. [PMID: 22869927 PMCID: PMC3477218 DOI: 10.1124/jpet.112.195255] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 08/02/2012] [Indexed: 11/22/2022] Open
Abstract
Nicotine, the major addictive agent in tobacco, is metabolized primarily by CYP2A6-catalyzed oxidation. The product of this reaction, 5'-hydroxynicotine, is in equilibrium with the nicotine Δ5'(1')iminium ion and is further metabolized to cotinine. We reported previously that both CYP2A6 and the closely related extrahepatic enzyme CYP2A13 were inactivated during nicotine metabolism; however, inactivation occurred after metabolism was complete. This led to the hypothesis that oxidation of a nicotine metabolite, possibly the nicotine Δ5'(1')iminium ion, was responsible for generating the inactivating species. In the studies presented here, we confirm that the nicotine Δ5'(1')iminium ion is an inactivator of both CYP2A6 and CYP2A13, and inactivation depends on time, concentration, and the presence of NADPH. Inactivation was not reversible and was accompanied by a parallel loss in spectrally active protein, as measured by reduced CO spectra. These data are consistent with the characterization of the nicotine Δ5'(1')iminium ion as a mechanism-based inactivator of both CYP2A13 and CYP2A6. We also confirm that both CYP2A6 and CYP2A13 catalyze the metabolism of the nicotine Δ5'(1')iminium ion to cotinine and provide evidence that both enzymes catalyze the sequential metabolism of the nicotine Δ5'(1')iminium ion. That is, a fraction of the cotinine formed may not be released from the enzyme before further oxidation to 3'-hydroxycotinine.
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Affiliation(s)
- Linda B von Weymarn
- Department of Biochemistry, Molecular Biology, and Biophysics, Masonic Cancer Center, University of Minnesota, Mayo Mail Code 806, 420 Delaware Street SE, Minneapolis, MN 55455, USA
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37
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Armstrong CT, Watkins DW, Anderson JLR. Constructing manmade enzymes for oxygen activation. Dalton Trans 2012; 42:3136-50. [PMID: 23076271 DOI: 10.1039/c2dt32010j] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Natural oxygenases catalyse the insertion of oxygen into an impressive array of organic substrates with exquisite efficiency, specificity and power unparalleled by current biomimetic catalysts. However, their true potential to provide tailor-made oxygenation catalysts remains largely untapped, perhaps a consequence of the evolutionary complexity imprinted into their three-dimensional structures through millennia of exposure to parallel selective pressures. In this perspective we describe how we may take inspiration from natural enzymes to design manmade oxygenase enzymes free from such complexity. We explore the differing chemistries accessed by natural oxygenases and outline a stepwise methodology whereby functional elements key to oxygenase catalysis are assembled within artificially designed protein scaffolds.
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Affiliation(s)
- Craig T Armstrong
- School of Biochemistry, University of Bristol, University Walk, Bristol, BS8 1TD, UK
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38
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Kwiecień RA, Le Questel JY, Lebreton J, Delaforge M, André F, Pihan E, Roussel A, Fournial A, Paneth P, Robins RJ. Cytochrome P450-Catalyzed Degradation of Nicotine: Fundamental Parameters Determining Hydroxylation by Cytochrome P450 2A6 at the 5′-Carbon or the N-Methyl Carbon. J Phys Chem B 2012; 116:7827-40. [DOI: 10.1021/jp304276v] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Renata A. Kwiecień
- Laboratory
for the Study of Biosynthesis by Isotopic Spectroscopy, Interdisciplinary
Chemistry: Synthesis, Analysis and Modeling (CEISAM), UMR6230, University of Nantes-CNRS, 2 rue de la Houssinière,
BP 92208, F-44322 Nantes 3, France
| | - Jean-Yves Le Questel
- Laboratory
for the Study of Biosynthesis by Isotopic Spectroscopy, Interdisciplinary
Chemistry: Synthesis, Analysis and Modeling (CEISAM), UMR6230, University of Nantes-CNRS, 2 rue de la Houssinière,
BP 92208, F-44322 Nantes 3, France
| | - Jacques Lebreton
- Laboratory
for the Study of Biosynthesis by Isotopic Spectroscopy, Interdisciplinary
Chemistry: Synthesis, Analysis and Modeling (CEISAM), UMR6230, University of Nantes-CNRS, 2 rue de la Houssinière,
BP 92208, F-44322 Nantes 3, France
| | - Marcel Delaforge
- Laboratoire Stress Oxydant et Détoxication, CNRS UMR8221, iBiTec-S/SB2SM, CEA Saclay, 91191 Saclay, France
| | - François André
- Laboratoire Stress Oxydant et Détoxication, CNRS UMR8221, iBiTec-S/SB2SM, CEA Saclay, 91191 Saclay, France
| | - Emilie Pihan
- Laboratoire Stress Oxydant et Détoxication, CNRS UMR8221, iBiTec-S/SB2SM, CEA Saclay, 91191 Saclay, France
| | - Anaïs Roussel
- Laboratoire Stress Oxydant et Détoxication, CNRS UMR8221, iBiTec-S/SB2SM, CEA Saclay, 91191 Saclay, France
| | - Anaïs Fournial
- Laboratory
for the Study of Biosynthesis by Isotopic Spectroscopy, Interdisciplinary
Chemistry: Synthesis, Analysis and Modeling (CEISAM), UMR6230, University of Nantes-CNRS, 2 rue de la Houssinière,
BP 92208, F-44322 Nantes 3, France
| | - Piotr Paneth
- Laboratory for Isotope Effects
Studies, Faculty of Chemistry, Institute
of Applied Radiation Chemistry, University of Technology Lodz, Zeromskiego 116, 90-924 Łodź, Poland
| | - Richard J. Robins
- Laboratory
for the Study of Biosynthesis by Isotopic Spectroscopy, Interdisciplinary
Chemistry: Synthesis, Analysis and Modeling (CEISAM), UMR6230, University of Nantes-CNRS, 2 rue de la Houssinière,
BP 92208, F-44322 Nantes 3, France
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DeVore NM, Scott EE. Nicotine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone binding and access channel in human cytochrome P450 2A6 and 2A13 enzymes. J Biol Chem 2012; 287:26576-85. [PMID: 22700965 DOI: 10.1074/jbc.m112.372813] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Cytochromes P450 (CYP) from the 2A subfamily are known for their roles in the metabolism of nicotine, the addictive agent in tobacco, and activation of the tobacco procarcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). Although both the hepatic CYP2A6 and respiratory CYP2A13 enzymes metabolize these compounds, CYP2A13 does so with much higher catalytic efficiency, but the structural basis for this has been unclear. X-ray structures of nicotine complexes with CYP2A13 (2.5 Å) and CYP2A6 (2.3 Å) yield a structural rationale for the preferential binding of nicotine to CYP2A13. Additional structures of CYP2A13 with NNK reveal either a single NNK molecule in the active site with orientations corresponding to metabolites known to form DNA adducts and initiate lung cancer (2.35 Å) or with two molecules of NNK bound (2.1 Å): one in the active site and one in a more distal staging site. Finally, in contrast to prior CYP2A structures with enclosed active sites, CYP2A13 conformations were solved that adopt both open and intermediate conformations resulting from an ∼2.5 Å movement of the F to G helices. This channel occurs in the same region where the second, distal NNK molecule is bound, suggesting that the channel may be used for ligand entry and/or exit from the active site. Altogether these structures provide multiple new snapshots of CYP2A13 conformations that assist in understanding the binding and activation of an important human carcinogen, as well as critical comparisons in the binding of nicotine, one of the most widely used and highly addictive drugs in human use.
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Affiliation(s)
- Natasha M DeVore
- Department of Medicinal Chemistry, The University of Kansas, Lawrence, Kansas 66045, USA
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40
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Li D, Wang Y, Han K. Recent density functional theory model calculations of drug metabolism by cytochrome P450. Coord Chem Rev 2012. [DOI: 10.1016/j.ccr.2012.01.016] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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41
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Kramlinger VM, von Weymarn LB, Murphy SE. Inhibition and inactivation of cytochrome P450 2A6 and cytochrome P450 2A13 by menthofuran, β-nicotyrine and menthol. Chem Biol Interact 2012; 197:87-92. [PMID: 22486895 PMCID: PMC3362486 DOI: 10.1016/j.cbi.2012.03.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 03/20/2012] [Accepted: 03/23/2012] [Indexed: 11/26/2022]
Abstract
Nicotine is the primary addictive agent in tobacco products and is metabolized in humans by CYP2A6. Decreased CYP2A6 activity has been associated with decreased smoking. The extrahepatic enzyme, CYP2A13 (94% identical to CYP2A6) also catalyzes the metabolism of nicotine, but is most noted for its role in the metabolic activation of the tobacco specific lung carcinogen, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). In this study, the inhibition and potential inactivation of CYP2A6 and CYP2A13 by two tobacco constituents, 1-methyl-4-(3-pyridinyl) pyrrole (β-nicotyrine) and (-)-menthol were characterized and compared to the potent mechanism based inactivator of CYP2A6, menthofuran. The effect of these compounds on CYP2A6 and CYP2A13 activity was significantly different. (-)-Menthol was a more efficient inhibitor of CYP2A13 than of CYP2A6 (KI, 8.2 μM and 110 μM, respectively). β-Nicotyrine was a potent inhibitor of CYP2A13 (KI, 0.17 μM). Neither menthol nor β-nicotyrine was an inactivator of CYP2A13. Whereas, β-nicotyrine was a mechanism based inactivator of CYP2A6 (KI(inact), 106 μM, kinact was 0.61 min(-1)). Similarly, menthofuran, a potent mechanism based inactivator of CYP2A6 did not inactivate CYP2A13. Menthofuran was an inhibitor of CYPA13 (KI, 1.24 μM). The inactivation of CYP2A6 by either β-nicotyrine or menthofuran was not due to modification of the heme and was likely due to modification of the apo-protein. These studies suggest that β-nicotyrine, but not menthol may influence nicotine and NNK metabolism in smokers.
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Affiliation(s)
- Valerie M Kramlinger
- Department of Biochemistry, Molecular Biology, and Biophysics, Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
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42
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Murphy SE, von Weymarn LB, Schutten MM, Kassie F, Modiano JF. Chronic nicotine consumption does not influence 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced lung tumorigenesis. Cancer Prev Res (Phila) 2011; 4:1752-60. [PMID: 22027684 DOI: 10.1158/1940-6207.capr-11-0366] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Nicotine replacement therapy is often used to maintain smoking cessation. However, concerns exist about the safety of long-term nicotine replacement therapy use in ex-smokers and its concurrent use in smokers. In this study, we determined the effect of nicotine administration on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumors in A/J mice. Female mice were administered a single dose of NNK (10 μmol) and 0.44 μmol/mL nicotine in the drinking water. Nicotine was administered 2 weeks prior to NNK, 44 weeks after NNK, throughout the experiment, or without NNK treatment. The average weekly consumption of nicotine-containing water was 15 ± 3 mL per mouse, resulting in an estimated daily nicotine dose of 0.9 μmol (0.15 mg) per mouse. Nicotine administration alone for 46 weeks did not increase lung tumor multiplicity (0.32 ± 0.1 vs. 0.53 ± 0.1 tumors per mouse). Lung tumor multiplicity in NNK-treated mice was 18.4 ± 4.5 and was not different for mice consuming nicotine before or after NNK administration, 21.9 ± 5.3 and 20.0 ± 5.4 tumors per mouse, respectively. Lung tumor multiplicity in animals consuming nicotine both before and after NNK administration was 20.4 ± 5.4. Tumor size and progression of adenomas to carcinomas was also not affected by nicotine consumption. In addition, nicotine consumption had no effect on the level of O(6)-methylguanine in the lung of NNK-treated mice. These negative findings in a commonly used model of human lung carcinogenesis should lead us to question the interpretation of the many in vitro studies that find that nicotine stimulates cancer cell growth.
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Affiliation(s)
- Sharon E Murphy
- Department of Biochemistry Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.
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Abstract
BACKGROUND Cigarette smoking and other forms of tobacco use are the leading cause of preventable mortality in the world. A better understanding of the etiology of nicotine addiction may help to increase the success rate of cessation and to decrease the massive morbidity and mortality associated with smoking. METHODS To identify genetic polymorphisms that contribute to nicotine dependence, our group undertook a genetic association study including three enzyme families that potentially influence nicotine metabolism: cytochrome P450 enzymes, flavin monooxygenases (FMOs), and UDP-glucuronosyl transferases. RESULTS Several polymorphisms in FMO1 showed association in a discovery sample, and were tested in an independent replication sample. One polymorphism, rs10912765, showed an association that remained significant after Bonferroni correction (nominal P=0.0067, corrected P=0.0134). Several additional polymorphisms in linkage disequilibrium with this single nucleotide polymorphism also showed association. Subsequent in-vitro experiments characterized FMO1 as a more efficient catalyst of nicotine N-oxidation than FMO3. In adult humans, FMO1 is primarily expressed in the kidney and is likely to be a major contributor to the renal metabolism and clearance of therapeutic drugs. FMO1 is also expressed in the brain and could contribute to the nicotine concentration in this tissue. CONCLUSION These findings suggest that polymorphisms in FMO1 are significant risk factors in the development of nicotine dependence and that the mechanism may involve variation in nicotine pharmacology.
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In vitro phase I metabolism of the depsipeptide enniatin B. Anal Bioanal Chem 2011; 400:2889-901. [DOI: 10.1007/s00216-011-4964-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 03/25/2011] [Accepted: 03/26/2011] [Indexed: 11/26/2022]
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Ghazi AM, Salhab AS, Arafat TA, Irshaid YM. Effect of Mint Drink on Metabolism of Nicotine as Measured by Nicotine to Cotinine Ratio in Urine of Jordanian Smoking Volunteers. Nicotine Tob Res 2011; 13:661-7. [DOI: 10.1093/ntr/ntr054] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Abdulrahman M Ghazi
- Department of Pharmacology, Faculty of Medicine, University of Jordan, Amman, Jordan
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Li D, Wang Y, Han K, Zhan CG. Fundamental reaction pathways for cytochrome P450-catalyzed 5'-hydroxylation and N-demethylation of nicotine. J Phys Chem B 2010; 114:9023-30. [PMID: 20572647 DOI: 10.1021/jp102225e] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The reaction pathways for 5'-hydroxylation and N-demethylation of nicotine catalyzed by cytochrome P450 were investigated by performing a series of first-principle electronic structure calculations on a catalytic reaction model system. The computational results indicate that 5'-hydroxylation of nicotine occurs through a two-state stepwise process, that is, an initial hydrogen atom transfer from nicotine to Cpd I (i.e., the HAT step) followed by a recombination of the nicotine moiety with the iron-bound hydroxyl group (i.e., the rebound step) on both the high-spin (HS) quartet and low-spin (LS) doublet states. The HAT step is the rate-determining one. This finding represents the first case that exhibits genuine rebound transition state species on both the HS and the LS states for C(alpha)-H hydroxylation of amines. N-Demethylation of nicotine involves a N-methylhydroxylation to form N-(hydroxymethyl)nornicotine, followed by N-(hydroxymethyl)nornicotine decomposition to nornicotine and formaldehyde. The N-methylhydroxylation step is similar to 5'-hydroxylation, namely, a rate-determining HAT step followed by a rebound step. The decomposition process occurs on the deprotonated state of N-(hydroxymethyl)nornicotine assisted by a water molecule, and the energy barrier is significantly lower than that of the N-methylhydroxylation process. Comparison of the rate-determining free energy barriers for the two reaction pathways predicts a preponderance of 5'-hydroxylation over the N-demethylation by roughly a factor of 18:1, which is in excellent agreement with the factor of 19:1 derived from available experimental data.
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Affiliation(s)
- Dongmei Li
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People's Republic of China
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Hădărugă DI, Hădărugă NG, Butnaru G, Tatu C, Gruia A. Bioactive microparticles (10): thermal and oxidative stability of nicotine and its complex with β-cyclodextrin. J INCL PHENOM MACRO 2010. [DOI: 10.1007/s10847-010-9761-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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48
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Zhou X, Zhuo X, Xie F, Kluetzman K, Shu YZ, Humphreys WG, Ding X. Role of CYP2A5 in the clearance of nicotine and cotinine: insights from studies on a Cyp2a5-null mouse model. J Pharmacol Exp Ther 2009; 332:578-87. [PMID: 19923441 DOI: 10.1124/jpet.109.162610] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
CYP2A5, a mouse cytochrome P450 monooxygenase that shows high similarities to human CYP2A6 and CYP2A13 in protein sequence and substrate specificity, is expressed in multiple tissues, including the liver, kidney, lung, and nasal mucosa. Heterologously expressed CYP2A5 is active in the metabolism of both endogenous substrates, such as testosterone, and xenobiotic compounds, such as nicotine and cotinine. To determine the biological and pharmacological functions of CYP2A5 in vivo, we have generated a Cyp2a5-null mouse. Homozygous Cyp2a5-null mice are viable and fertile; they show no evidence of embryonic lethality or developmental deficits; and they have normal circulating levels of testosterone and progesterone. The Cyp2a5-null mouse and wild-type mouse were then used for determination of the roles of CYP2A5 in the metabolism of nicotine and its major circulating metabolite, cotinine. The results indicated that the Cyp2a5-null mouse has lower hepatic nicotine 5'-hydroxylation activity in vitro, and slower systemic clearance of both nicotine and cotinine in vivo. For both compounds, a substantially longer plasma half-life and a greater area under the concentration-time curve were observed for the Cyp2a5-null mice, compared with wild-type mice. Further pharmacokinetics analysis confirmed that the brain levels of nicotine and cotinine are also influenced by the Cyp2a5 deletion. These findings provide direct evidence that CYP2A5 is the major nicotine and cotinine oxidase in mouse liver. The Cyp2a5-null mouse will be valuable for in vivo studies on the role of CYP2A5 in drug metabolism and chemical toxicity, and for future production of CYP2A6- and CYP2A13-humanized mouse models.
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Affiliation(s)
- Xin Zhou
- Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY 12201-0509, USA.
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Berg JZ, Mason J, Boettcher AJ, Hatsukami DK, Murphy SE. Nicotine metabolism in African Americans and European Americans: variation in glucuronidation by ethnicity and UGT2B10 haplotype. J Pharmacol Exp Ther 2009; 332:202-9. [PMID: 19786624 DOI: 10.1124/jpet.109.159855] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nicotine is the major addictive agent in tobacco smoke, and it is metabolized extensively by oxidation and glucuronide conjugation. The contributions of ethnicity and UGT2B10 haplotype on variation in nicotine metabolism were investigated. Nicotine metabolism was evaluated in two populations of smokers. In one population of African American and European American smokers (n = 93), nicotine and its metabolites were analyzed in plasma and 24-h urine over 3 days while participants were abstinent and at steady state on the nicotine patch. In a second study of smokers (n = 84), the relationship of a UGT2B10 haplotype linked with D67Y to nicotine and cotinine glucuronidation levels was determined. We observed that both African American ethnicity and the UGT2B10 D67Y allele were associated with a low glucuronidation phenotype. African Americans excreted less nicotine and cotinine as their glucuronide conjugates compared with European Americans; percentage of nicotine glucuronidation, 18.1 versus 29.3 (p < 0.002) and percentage of cotinine glucuronidation, 41.4 versus 61.7 (p < 0.0001). In smokers with a UGT2B10 Tyr67 allele, glucuronide conjugation of nicotine and cotinine was decreased by 20% compared with smokers without this allele. Two key outcomes are reported here. First, the observation that African Americans have lower nicotine and cotinine glucuronidation was confirmed in a population of abstinent smokers on the nicotine patch. Second, we provide the first convincing evidence that UGT2B10 is a key catalyst of these glucuronidation pathways in vivo.
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Affiliation(s)
- Jeannette Zinggeler Berg
- Department of Biochemistry, Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
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Zhou SF, Liu JP, Chowbay B. Polymorphism of human cytochrome P450 enzymes and its clinical impact. Drug Metab Rev 2009; 41:89-295. [PMID: 19514967 DOI: 10.1080/03602530902843483] [Citation(s) in RCA: 502] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Pharmacogenetics is the study of how interindividual variations in the DNA sequence of specific genes affect drug response. This article highlights current pharmacogenetic knowledge on important human drug-metabolizing cytochrome P450s (CYPs) to understand the large interindividual variability in drug clearance and responses in clinical practice. The human CYP superfamily contains 57 functional genes and 58 pseudogenes, with members of the 1, 2, and 3 families playing an important role in the metabolism of therapeutic drugs, other xenobiotics, and some endogenous compounds. Polymorphisms in the CYP family may have had the most impact on the fate of therapeutic drugs. CYP2D6, 2C19, and 2C9 polymorphisms account for the most frequent variations in phase I metabolism of drugs, since almost 80% of drugs in use today are metabolized by these enzymes. Approximately 5-14% of Caucasians, 0-5% Africans, and 0-1% of Asians lack CYP2D6 activity, and these individuals are known as poor metabolizers. CYP2C9 is another clinically significant enzyme that demonstrates multiple genetic variants with a potentially functional impact on the efficacy and adverse effects of drugs that are mainly eliminated by this enzyme. Studies into the CYP2C9 polymorphism have highlighted the importance of the CYP2C9*2 and *3 alleles. Extensive polymorphism also occurs in other CYP genes, such as CYP1A1, 2A6, 2A13, 2C8, 3A4, and 3A5. Since several of these CYPs (e.g., CYP1A1 and 1A2) play a role in the bioactivation of many procarcinogens, polymorphisms of these enzymes may contribute to the variable susceptibility to carcinogenesis. The distribution of the common variant alleles of CYP genes varies among different ethnic populations. Pharmacogenetics has the potential to achieve optimal quality use of medicines, and to improve the efficacy and safety of both prospective and currently available drugs. Further studies are warranted to explore the gene-dose, gene-concentration, and gene-response relationships for these important drug-metabolizing CYPs.
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Affiliation(s)
- Shu-Feng Zhou
- School of Health Sciences, RMIT University, Bundoora, Victoria, Australia.
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