1
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Uhlig S, Olderbø BP, Samuelsen JT, Uvsløkk S, Ivanova L, Vanderstraeten C, Grutle LA, Rangel-Huerta OD. Mass spectrometry-based metabolomics study of nicotine exposure in THP-1 monocytes. Sci Rep 2024; 14:14957. [PMID: 38942832 PMCID: PMC11213872 DOI: 10.1038/s41598-024-65733-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 06/24/2024] [Indexed: 06/30/2024] Open
Abstract
The tobacco alkaloid nicotine is known for its activation of neuronal nicotinic acetylcholine receptors. Nicotine is consumed in different ways such as through conventional smoking, e-cigarettes, snuff or nicotine pouches. The use of snuff has been associated with several adverse health effects, such as inflammatory reactions of the oral mucosa and oral cavity cancer. We performed a metabolomic analysis of nicotine-exposed THP-1 human monocytes. Cells were exposed to 5 mM of the alkaloid for up to 4 h, and cell extracts and medium subjected to untargeted liquid chromatography high-resolution mass spectrometry. Raw data processing revealed 17 nicotine biotransformation products. Among these, cotinine and nornicotine were identified as the two major cellular biotransformation products. The application of multi- and univariate statistical analyses resulted in the annotation, up to a certain level of identification, of 12 compounds in the cell extracts and 13 compounds in the medium that were altered by nicotine exposure. Of these, four were verified as methylthioadenosine, cytosine, uric acid, and L-glutamate. Methylthioadenosine levels were affected in both cells and the medium, while cytosine, uric acid, and L-glutamate levels were affected in the medium only. The effects of smoking on the pathways involving these metabolites have been previously demonstrated in humans. Most of the other discriminating compounds, which were merely tentatively or not fully identified, were amino acids or amino acid derivatives. In conclusion, our preliminary data suggest that some of the potentially adverse effects related to smoking may also be expected when nicotine is consumed via snuff or nicotine pouches.
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Affiliation(s)
- Silvio Uhlig
- Nordic Institute of Dental Materials, Sognsveien 70A, 0855, Oslo, Norway.
| | | | - Jan Tore Samuelsen
- Nordic Institute of Dental Materials, Sognsveien 70A, 0855, Oslo, Norway
| | - Solveig Uvsløkk
- Nordic Institute of Dental Materials, Sognsveien 70A, 0855, Oslo, Norway
| | - Lada Ivanova
- Toxinology Research Group, Norwegian Veterinary Institute, P.O. Box 64, 1431, Ås, Norway
| | - Camille Vanderstraeten
- Nordic Institute of Dental Materials, Sognsveien 70A, 0855, Oslo, Norway
- Department of Bioanalysis, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000, Gent, Belgium
| | - Lene Aiko Grutle
- Nordic Institute of Dental Materials, Sognsveien 70A, 0855, Oslo, Norway
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2
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Zeng T, Liu Y, Jiang Y, Zhang L, Zhang Y, Zhao L, Jiang X, Zhang Q. Advanced Materials Design for Adsorption of Toxic Substances in Cigarette Smoke. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023:e2301834. [PMID: 37211707 PMCID: PMC10401148 DOI: 10.1002/advs.202301834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 04/27/2023] [Indexed: 05/23/2023]
Abstract
Cigarettes, despite being economically important legal consumer products, are highly addictive and harmful, particularly to the respiratory system. Tobacco smoke is a complex mixture containing over 7000 chemical compounds, 86 of which are identified to have "sufficient evidence of carcinogenicity" in either animal or human tests. Thus, tobacco smoke poses a significant health risk to humans. This article focuses on materials that help reduce the levels of major carcinogens in cigarette smoke; these include nicotine, polycyclic aromatic hydrocarbons, tobacco-specific nitrosamines, hydrogen cyanide, carbon monoxide, and formaldehyde. Specifically, the research progress on adsorption effects and mechanisms of advanced materials such as cellulose, zeolite, activated carbon, graphene, and molecularly imprinted polymers are highlighted. The future trends and prospects in this field are also discussed. Notably, with advancements in supramolecular chemistry and materials engineering, the design of functionally oriented materials has become increasingly multidisciplinary. Certainly, several advanced materials can play a critical role in reducing the harmful effects of cigarette smoke. This review aims to serve as an insightful reference for the design of hybrid and functionally oriented advanced materials.
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Affiliation(s)
- Ting Zeng
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, 611731, China
- Research Center, Chengdu Medical College, Chengdu, 610500, China
| | - Yanxia Liu
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, 611731, China
| | - Yingfang Jiang
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, 611731, China
| | - Lan Zhang
- Univ Lyon, CNRS, INSA-Lyon, Université Claude Bernard Lyon 1, CETHIL UMR5008, Villeurbanne, F-69621, France
| | - Yagang Zhang
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, 611731, China
| | - Lin Zhao
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, 611731, China
| | - Xiaoli Jiang
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, 611731, China
| | - Qiang Zhang
- Department of Chemistry, Washington State University, Pullman, WA, 99164, USA
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3
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Haas J, Beck E, Troczka BJ, Hayward A, Hertlein G, Zaworra M, Lueke B, Buer B, Maiwald F, Beck ME, Nebelsiek B, Glaubitz J, Bass C, Nauen R. A conserved hymenopteran-specific family of cytochrome P450s protects bee pollinators from toxic nectar alkaloids. SCIENCE ADVANCES 2023; 9:eadg0885. [PMID: 37043574 PMCID: PMC10096648 DOI: 10.1126/sciadv.adg0885] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 03/09/2023] [Indexed: 06/19/2023]
Abstract
Many plants produce chemical defense compounds as protection against antagonistic herbivores. However, how beneficial insects such as pollinators deal with the presence of these potentially toxic chemicals in nectar and pollen is poorly understood. Here, we characterize a conserved mechanism of plant secondary metabolite detoxification in the Hymenoptera, an order that contains numerous highly beneficial insects. Using phylogenetic and functional approaches, we show that the CYP336 family of cytochrome P450 enzymes detoxifies alkaloids, a group of potent natural insecticides, in honeybees and other hymenopteran species that diverged over 281 million years. We linked this function to an aspartic acid residue within the main access channel of CYP336 enzymes that is highly conserved within this P450 family. Together, these results provide detailed insights into the evolution of P450s as a key component of detoxification systems in hymenopteran species and reveal the molecular basis of adaptations arising from interactions between plants and beneficial insects.
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Affiliation(s)
- Julian Haas
- Crop Science Division, Bayer AG, Alfred Nobel-Strasse 50, Monheim, Germany
| | - Elena Beck
- Crop Science Division, Bayer AG, Alfred Nobel-Strasse 50, Monheim, Germany
- University of Cologne, Department of Chemistry, Institute of Biochemistry, Cologne, Germany
| | - Bartlomiej J. Troczka
- College for Life and Environmental Sciences, University of Exeter, Penryn, Cornwall, UK
| | - Angela Hayward
- College for Life and Environmental Sciences, University of Exeter, Penryn, Cornwall, UK
| | - Gillian Hertlein
- Crop Science Division, Bayer AG, Alfred Nobel-Strasse 50, Monheim, Germany
| | - Marion Zaworra
- Crop Science Division, Bayer AG, Alfred Nobel-Strasse 50, Monheim, Germany
| | - Bettina Lueke
- Crop Science Division, Bayer AG, Alfred Nobel-Strasse 50, Monheim, Germany
| | - Benjamin Buer
- Crop Science Division, Bayer AG, Alfred Nobel-Strasse 50, Monheim, Germany
| | - Frank Maiwald
- Crop Science Division, Bayer AG, Alfred Nobel-Strasse 50, Monheim, Germany
| | - Michael E. Beck
- Crop Science Division, Bayer AG, Alfred Nobel-Strasse 50, Monheim, Germany
| | - Birgit Nebelsiek
- Crop Science Division, Bayer AG, Alfred Nobel-Strasse 50, Monheim, Germany
| | - Johannes Glaubitz
- Crop Science Division, Bayer AG, Alfred Nobel-Strasse 50, Monheim, Germany
| | - Chris Bass
- College for Life and Environmental Sciences, University of Exeter, Penryn, Cornwall, UK
| | - Ralf Nauen
- Crop Science Division, Bayer AG, Alfred Nobel-Strasse 50, Monheim, Germany
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4
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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: 8] [Impact Index Per Article: 8.0] [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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5
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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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6
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Perez-Paramo YX, Watson CJ, Chen G, Thomas CE, Adams-Haduch J, Wang R, Khor CC, Koh WP, Nelson HH, Yuan JM, Lazarus P. Impact of Genetic Variants in the Nicotine Metabolism Pathway on Nicotine Metabolite Levels in Smokers. Cancer Epidemiol Biomarkers Prev 2023; 32:54-65. [PMID: 36252563 PMCID: PMC9827107 DOI: 10.1158/1055-9965.epi-22-0868] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 09/14/2022] [Accepted: 10/11/2022] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Nicotine metabolism is a major factor in nicotine dependence, with approximately 70% to 80% of nicotine metabolized to cotinine in Caucasians. Cotinine formation is catalyzed primarily by CYP2A6, which also converts cotinine to trans-3'-hydroxycotinine (3HC). The goal of the present study was to examine the effects of CYP2A6 deficiency on nicotine metabolism profiles in vivo and the importance of genetic variants in nicotine-metabolizing enzyme genes on urinary nicotine metabolites levels. METHODS Urine samples from 722 smokers who participated in the Singapore Chinese Health Study were analyzed using UPLC-MS/MS to detect nicotine and eight of its urinary metabolites, and a total of 58 variants in 12 genes involved in nicotine metabolism were investigated in 475 of these subjects with informative genotyping data. RESULTS Urine samples stratified by the ratio of 3HC/cotinine exhibited a 7-fold increase in nicotine-N'-oxide, a 6-fold increase in nicotine-Glucuronide (Gluc), and a 5-fold decrease in 3HC-Gluc when comparing the lower versus upper 3HC/cotinine ventiles. Significant (P < 0.0001) associations were observed between functional metabolizing enzyme genotypes and levels of various urinary nicotine metabolites, including CYP2A6 genotype and levels of nicotine, nicotine-Gluc, nicotine-N'-oxide and 3HC, UGT2B10 genotype and levels of cotinine, nicotine-Gluc and cotinine-Gluc, UGT2B17 genotype and levels of 3HC-Gluc, FMO3 genotype and levels of nicotine-N'-oxide, and CYP2B6 genotype and levels of nicotine-N'-oxide and 4-hydroxy-4-(3-pyridyl)-butanoic acid. CONCLUSIONS These data suggest that several pathways are important in nicotine metabolism. IMPACT Genotype differences in several nicotine-metabolizing enzyme pathways may potentially lead to differences in nicotine dependence and smoking behavior and cessation.
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Affiliation(s)
- Yadira X. Perez-Paramo
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Christy J.W. Watson
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Gang Chen
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Claire E. Thomas
- Division of Cancer Control and Population Sciences, UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Jennifer Adams-Haduch
- Division of Cancer Control and Population Sciences, UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Renwei Wang
- Division of Cancer Control and Population Sciences, UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Chiea Chuen Khor
- Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, Singapore.,Singapore Eye Research Institute, Singapore, Singapore.,Eye Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore
| | - Woon-Puay Koh
- Health Services and Systems Research, Duke-NUS Medical School Singapore, Singapore, Singapore.,Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore
| | - Heather H. Nelson
- Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota.,Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, Minnesota
| | - Jian-Min Yuan
- Division of Cancer Control and Population Sciences, UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania.,Corresponding Authors: Philip Lazarus, College of Pharmacy and Pharmaceutical Sciences, Washington State University, PBS building, Room 431, Spokane, Washington, 99210-1495. E-mail: ; and Jian-Min Yuan, Division of Cancer Control and Population Sciences, UPMC Hillman Cancer Center, University of Pittsburgh, 5150 Centre Avenue, Pittsburgh, Pennsylvania, 15232. E-mail:
| | - Philip Lazarus
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington.,Corresponding Authors: Philip Lazarus, College of Pharmacy and Pharmaceutical Sciences, Washington State University, PBS building, Room 431, Spokane, Washington, 99210-1495. E-mail: ; and Jian-Min Yuan, Division of Cancer Control and Population Sciences, UPMC Hillman Cancer Center, University of Pittsburgh, 5150 Centre Avenue, Pittsburgh, Pennsylvania, 15232. E-mail:
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7
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Li Y, Hecht SS. Metabolism and DNA Adduct Formation of Tobacco-Specific N-Nitrosamines. Int J Mol Sci 2022; 23:5109. [PMID: 35563500 PMCID: PMC9104174 DOI: 10.3390/ijms23095109] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 04/29/2022] [Accepted: 04/30/2022] [Indexed: 01/06/2023] Open
Abstract
The tobacco-specific N-nitrosamines 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN) always occur together and exclusively in tobacco products or in environments contaminated by tobacco smoke. They have been classified as "carcinogenic to humans" by the International Agency for Research on Cancer. In 1998, we published a review of the biochemistry, biology and carcinogenicity of tobacco-specific nitrosamines. Over the past 20 years, considerable progress has been made in our understanding of the mechanisms of metabolism and DNA adduct formation by these two important carcinogens, along with progress on their carcinogenicity and mutagenicity. In this review, we aim to provide an update on the carcinogenicity and mechanisms of the metabolism and DNA interactions of NNK and NNN.
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Affiliation(s)
- Yupeng Li
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA;
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, MN 55455, USA
| | - Stephen S. Hecht
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA;
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8
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Ishii H, Leung GNW, Yamashita S, Nagata SI, Kushiro A, Sakai S, Toju K, Okada J, Kawasaki K, Kusano K, Kijima-Suda I. Comprehensive metabolic study of nicotine in equine plasma and urine using liquid chromatography/high-resolution mass spectrometry for the identification of unique biomarkers for doping control. J Chromatogr B Analyt Technol Biomed Life Sci 2022; 1190:123100. [PMID: 35032890 DOI: 10.1016/j.jchromb.2022.123100] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 12/07/2021] [Accepted: 01/03/2022] [Indexed: 10/19/2022]
Abstract
Nicotine is classified as a stimulant, and its use is banned in horse racing and equestrian sports by the International Federation of Horseracing Authorities and the Fédération Équestre Internationale, respectively. Because nicotine is a major alkaloid of tobacco leaves, there is a potential risk that doping control samples may be contaminated by tobacco cigarettes or smoke during sample collection. In order to differentiate the genuine doping and sample contamination with tobacco leaves, it is necessary to monitor unique metabolites as biomarkers for nicotine administration and intake. However, little is known about the metabolic fate of nicotine in horses. This is the first report of comprehensive metabolism study of nicotine in horses. Using liquid chromatography/electrospray ionization high-resolution mass spectrometry, we identified a total of 17 metabolites, including one novel horse-specific metabolite (i.e., 4-hydroxy-4-(3-pyridyl)-N-methylbutanamide), in post-administration urine samples after nasoesophageal administration of nicotine to three thoroughbred mares; eight of these compounds were confirmed based on reference standards. Among these metabolites, N-hydroxymethylnorcotinine was the major urinary metabolite in equine, but it could only be tentatively identified by mass spectral interpretation due to the lack of reference material. In addition, we developed simultaneous quantification methods for the eight target analytes in plasma and urine, and applied them to post-administration samples to establish elimination profiles of nicotine and its metabolites. The quantification results revealed that trans-3'-hydroxycotinine could be quantified for the longest period in both plasma (72 h post-administration) and urine (96 h post-administration). Therefore, this metabolite is the most appropriate monitoring target for nicotine exposure for the purpose of doping control due to its long detection times and the availability of its reference material. Further, we identified trans-3'-hydroxycotinine as a unique biomarker allowing differentiation between nicotine administration and sample contamination with tobacco leaves.
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Affiliation(s)
- Hideaki Ishii
- Drug Analysis Department, Laboratory of Racing Chemistry, 1731-2 Tsuruta-machi, Utsunomiya, Tochigi 320-0851, Japan; Department of Pharmaceutical Sciences, Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8574, Japan.
| | - Gary Ngai-Wa Leung
- Drug Analysis Department, Laboratory of Racing Chemistry, 1731-2 Tsuruta-machi, Utsunomiya, Tochigi 320-0851, Japan
| | - Shozo Yamashita
- Drug Analysis Department, Laboratory of Racing Chemistry, 1731-2 Tsuruta-machi, Utsunomiya, Tochigi 320-0851, Japan
| | - Shun-Ichi Nagata
- Genetic Analysis Department, Laboratory of Racing Chemistry, 1731-2 Tsuruta-machi, Utsunomiya, Tochigi 320-0851, Japan
| | - Asuka Kushiro
- Equine Research Institute, Research Planning & Coordination Division, JRA, 1400-4, Shiba, Shimotsuke, Tochigi 329-0412, Japan
| | - Satoshi Sakai
- Race Horse Hospital, Miho Training Center, JRA, 2500-2, Oaza-Mikoma, Miho-mura, Inashiki-gun, Ibaraki 300-0493, Japan
| | - Kota Toju
- Race Horse Hospital, Miho Training Center, JRA, 2500-2, Oaza-Mikoma, Miho-mura, Inashiki-gun, Ibaraki 300-0493, Japan
| | - Jun Okada
- Veterinarian Section, Equine Department, JRA, 6-11-1 Roppongi, Minato-ku, Tokyo 105-0003, Japan
| | - Kazumi Kawasaki
- Veterinarian Section, Equine Department, JRA, 6-11-1 Roppongi, Minato-ku, Tokyo 105-0003, Japan
| | - Kanichi Kusano
- Race Horse Hospital, Ritto Training Center, JRA, 1028, Misono, Ritto, Shiga 520-3085, Japan
| | - Isao Kijima-Suda
- Drug Analysis Department, Laboratory of Racing Chemistry, 1731-2 Tsuruta-machi, Utsunomiya, Tochigi 320-0851, Japan
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9
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Nwabufo CK, Aigbogun OP, Allen KJH, Owens MN, Lee JS, Phenix CP, Krol ES. Employing in vitro metabolism to guide design of F-labelled PET probes of novel α-synuclein binding bifunctional compounds. Xenobiotica 2021; 51:885-900. [PMID: 34187286 DOI: 10.1080/00498254.2021.1943566] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
A challenge in the development of novel 18F-labelled positron emission tomography (PET) imaging probes is identification of metabolically stable sites to incorporate the 18F radioisotope. Metabolic loss of 18F from PET probes in vivo can lead to misleading biodistribution data as displaced 18F can accumulate in various tissues.In this study we report on in vitro hepatic microsomal metabolism of novel caffeine containing bifunctional compounds (C8-6-I, C8-6-N, C8-6-C8) that can prevent in vitro aggregation of α-synuclein, which is associated with the pathophysiology of Parkinson's disease. The metabolic profile obtained guided us to synthesize stable isotope 19F-labelled analogues in which the fluorine was introduced at the metabolically stable N7 of the caffeine moiety.An in vitro hepatic microsomal metabolism study of the 19F-labelled analogues resulted in similar metabolites to the unlabelled compounds and demonstrated that the fluorine was metabolically stable, suggesting that these analogues are appropriate PET imaging probes. This straightforward in vitro strategy is valuable for avoiding costly stability failures when designing radiolabelled compounds for PET imaging.
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Affiliation(s)
- Chukwunonso K Nwabufo
- Drug Discovery and Development Research Group, College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, Canada
| | | | - Kevin J H Allen
- Drug Discovery and Development Research Group, College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, Canada
| | - Madeline N Owens
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, Canada
| | - Jeremy S Lee
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, Canada
| | | | - Ed S Krol
- Drug Discovery and Development Research Group, College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, Canada
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10
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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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11
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Sun HN, Ren CX, Gong YX, Xie DP, Kwon T. Regulatory function of peroxiredoxin I on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced lung cancer development. Oncol Lett 2021; 21:465. [PMID: 33907575 PMCID: PMC8063228 DOI: 10.3892/ol.2021.12726] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 03/17/2021] [Indexed: 12/18/2022] Open
Abstract
Smoking is a major cause of lung cancer, and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is one of the most important carcinogens in cigarette smoke. NNK modulates the expression of peroxiredoxin (Prdx) I in lung cancer. Prdx1 is upregulated in lung squamous cell carcinoma and lung adenocarcinoma, and considered a potential biomarker for lung cancer. The current article reviewed the role and regulatory mechanisms of Prdx1 in NNK-induced lung cancer cells. Prdx1 protects erythrocytes and DNA from NNK-induced oxidative damage, prevents malignant transformation of cells and promotes cytotoxicity of natural killer cells, hence suppressing tumor formation. In addition, Prdx1 has the ability to prevent NNK-induced lung tumor metabolic activity and generation of large amount of reactive oxygen species (ROS) and ROS-induced apoptosis, thus promoting tumor cell survival. In contrast to this, Prdx1, together with NNK, can promote the epithelial-mesenchymal transition and migration of lung tumor cells. The signaling pathways associated with NNK and Prdx1 in lung cancer cells have been discussed in present review; however, numerous potential pathways are yet to be studied. To develop novel methods for treating NNK-induced lung cancer, and improve the survival rate of patients with lung cancer, further research is needed to understand the complete mechanism associated with NNK.
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Affiliation(s)
- Hu-Nan Sun
- College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, Heilongjiang 163319, P.R. China
| | - Chen-Xi Ren
- College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, Heilongjiang 163319, P.R. China
| | - Yi-Xi Gong
- College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, Heilongjiang 163319, P.R. China
| | - Dan-Ping Xie
- College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, Heilongjiang 163319, P.R. China
| | - Taeho Kwon
- Primate Resources Center, Korea Research Institute of Bioscience and Biotechnology, Jeongeup, Jeonbuk 56216, Republic of Korea
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12
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Perez-Paramo YX, Lazarus P. Pharmacogenetics factors influencing smoking cessation success; the importance of nicotine metabolism. Expert Opin Drug Metab Toxicol 2021; 17:333-349. [PMID: 33322962 PMCID: PMC8049967 DOI: 10.1080/17425255.2021.1863948] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 12/10/2020] [Indexed: 01/12/2023]
Abstract
Introduction: Smoking remains a worldwide epidemic, and despite an increase in public acceptance of the harms of tobacco use, it remains the leading cause of preventable death. It is estimated that up to 70% of all smokers express a desire to quit, but only 3-5% of them are successful.Areas covered: The goal of this review was to evaluate the current status of smoking cessation treatments and the feasibility of implementing personalized-medicine approaches to these pharmacotherapies. We evaluated the genetics associated with higher levels of nicotine addiction and follow with an analysis of the genetic variants that affect the nicotine metabolic ratio (NMR) and the FDA approved treatments for smoking cessation. We also highlighted the gaps in the process of translating current laboratory understanding into clinical practice, and the benefits of personalized treatment approaches for a successful smoking cessation strategy.Expert opinion: Evidence supports the use of tailored therapies to ensure that the most efficient treatments are utilized in an individual's smoking cessation efforts. An understanding of the genetic effects on the efficacy of individualized smoking cessation pharmacotherapies is key to smoking cessation, ideally utilizing a polygenetic risk score that considers all genetic variation.
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Affiliation(s)
- Yadira X. Perez-Paramo
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington, USA
| | - Philip Lazarus
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington, USA
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13
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de la Monte SM, Moriel N, Lin A, Abdullah Tanoukhy N, Homans C, Gallucci G, Tong M, Saito A. Betel Quid Health Risks of Insulin Resistance Diseases in Poor Young South Asian Native and Immigrant Populations. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17186690. [PMID: 32937888 PMCID: PMC7558723 DOI: 10.3390/ijerph17186690] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/02/2020] [Accepted: 09/03/2020] [Indexed: 01/30/2023]
Abstract
Betel quid, traditionally prepared with areca nut, betel leaf, and slaked lime, has been consumed for thousands of years, mainly in the form of chewing. Originally used for cultural, medicinal, and ceremonial purposes mainly in South Asian countries, its use has recently spread across the globe due to its psychoactive, euphoric, and aphrodisiac properties. Now it is widely used as a social lubricant and source of financial profit. Unfortunately, the profit motive has led to high rates of habitual consumption with eventual conversion to addiction among young girls and boys. Moreover, the worrisome practice of including tobacco in quid preparations has grown, particularly among pregnant women. Major health concerns include increased rates of malignancy, oral pathology, and cardiovascular, hepatic, fertility, metabolic, and neuropsychiatric disorders. Metabolic disorders and insulin resistance disease states such as type 2 diabetes, obesity, and metabolic syndrome contribute to cognitive decline and neurodegeneration. Mechanistically, the constituents of areca nut/betel quid are metabolized to N-nitroso compounds, i.e., nitrosamines, which are carcinogenic at high doses and cause insulin resistance following chronic low-level exposures. From an epidemiological perspective, the rising tide of insulin resistance diseases including obesity, diabetes, and dementias that now disproportionately burden poor countries has been propagated by rapid commercialization and enhanced access to betel quid. Public health measures are needed to impose socially and ethically responsible barriers to yet another cause of global health disparity.
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Affiliation(s)
- Suzanne M. de la Monte
- Department of Pathology and Laboratory Medicine, Providence VA Medical Center, Providence, RI 02808, USA
- Women & Infants Hospital of Rhode Island, Providence, RI 02808, USA
- Alpert Medical School, Brown University, Providence, RI 02808, USA
- Departments of Medicine, Rhode Island Hospital, Providence, RI 02808, USA; (G.G.); (M.T.)
- Neurology, Neurosurgery and Neuropathology, Rhode Island Hospital, Alpert Medical School of Brown University, Providence, RI 02903, USA
- Correspondence:
| | - Natalia Moriel
- Department of Molecular Pharmacology and Physiology at Brown University, Providence, RI 02912, USA; (N.M.); (A.L.); (N.A.T.)
| | - Amy Lin
- Department of Molecular Pharmacology and Physiology at Brown University, Providence, RI 02912, USA; (N.M.); (A.L.); (N.A.T.)
| | - Nada Abdullah Tanoukhy
- Department of Molecular Pharmacology and Physiology at Brown University, Providence, RI 02912, USA; (N.M.); (A.L.); (N.A.T.)
| | - Camille Homans
- Department of Neuroscience, Brown University, Providence, RI 02912, USA;
| | - Gina Gallucci
- Departments of Medicine, Rhode Island Hospital, Providence, RI 02808, USA; (G.G.); (M.T.)
| | - Ming Tong
- Departments of Medicine, Rhode Island Hospital, Providence, RI 02808, USA; (G.G.); (M.T.)
| | - Ayumi Saito
- Department of Epidemiology in the School of Public Health, Brown University, Providence, RI 02912, USA;
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14
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Moerke MJ, McMahon LR, Wilkerson JL. More than Smoke and Patches: The Quest for Pharmacotherapies to Treat Tobacco Use Disorder. Pharmacol Rev 2020; 72:527-557. [PMID: 32205338 DOI: 10.1124/pr.119.018028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Tobacco use is a persistent public health issue. It kills up to half its users and is the cause of nearly 90% of all lung cancers. The main psychoactive component of tobacco is nicotine, primarily responsible for its abuse-related effects. Accordingly, most pharmacotherapies for smoking cessation target nicotinic acetylcholine receptors (nAChRs), nicotine's major site of action in the brain. The goal of the current review is twofold: first, to provide a brief overview of the most commonly used behavioral procedures for evaluating smoking cessation pharmacotherapies and an introduction to pharmacokinetic and pharmacodynamic properties of nicotine important for consideration in the development of new pharmacotherapies; and second, to discuss current and potential future pharmacological interventions aimed at decreasing tobacco use. Attention will focus on the potential for allosteric modulators of nAChRs to offer an improvement over currently approved pharmacotherapies. Additionally, given increasing public concern for the potential health consequences of using electronic nicotine delivery systems, which allow users to inhale aerosolized solutions as an alternative to smoking tobacco, an effort will be made throughout this review to address the implications of this relatively new form of nicotine delivery, specifically as it relates to smoking cessation. SIGNIFICANCE STATEMENT: Despite decades of research that have vastly improved our understanding of nicotine and its effects on the body, only a handful of pharmacotherapies have been successfully developed for use in smoking cessation. Thus, investigation of alternative pharmacological strategies for treating tobacco use disorder remains active; allosteric modulators of nicotinic acetylcholine receptors represent one class of compounds currently under development for this purpose.
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Affiliation(s)
- M J Moerke
- Division of Preclinical Pharmacology, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland (M.J.M.) and Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida (L.R.M., J.L.W.)
| | - L R McMahon
- Division of Preclinical Pharmacology, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland (M.J.M.) and Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida (L.R.M., J.L.W.)
| | - J L Wilkerson
- Division of Preclinical Pharmacology, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland (M.J.M.) and Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida (L.R.M., J.L.W.)
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15
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Kankanamage RNT, Ghosh AB, Jiang D, Gkika K, Keyes T, Achola LA, Suib S, Rusling JF. Metabolites of Tobacco- and E-Cigarette-Related Nitrosamines Can Drive Cu 2+-Mediated DNA Oxidation. Chem Res Toxicol 2020; 33:2072-2086. [PMID: 32672941 PMCID: PMC7510339 DOI: 10.1021/acs.chemrestox.0c00027] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Nitrosamine metabolites resulting from cigarette smoking and E-cigarette (E-cig) vaping cause DNA damage that can lead to genotoxicity. While DNA adducts of metabolites of nitrosamines 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N-nitrosonornicotine (NNN) are well-known tobacco-related cancer biomarkers, only a few studies implicate NNN and NNK in DNA oxidation in humans. NNK and NNN were found in the urine of E-cigarette users who never smoked cigarettes. This paper proposes the first chemical pathways of DNA oxidation driven by NNK and NNN metabolites in redox reactions with Cu2+ and NADPH leading to reactive oxygen species (ROS). A microfluidic array with thin films of DNA and metabolic enzymes that make metabolites of NNN and NNK in the presence of Cu2+ and NADPH was used to estimate relative rates of DNA oxidation. Detection by electrochemiluminescence (ECL) employed a new ECL dye [Os(tpy-benz-COOH)2]2+ that is selective for and sensitive to the primary DNA oxidation product 8-oxo-7,8-dihydro-2-deoxyguanosine (8-oxodG) in DNA. Enzyme-DNA films on magnetic beads were used to produce nitrosamine metabolites that enter ROS-forming redox cycles with Cu2+ and NADPH, and liquid chromatography-mass spectrometry (LC-MS) was used to quantify 8-oxodG and identify metabolites. ROS were detected by optical sensors. Metabolites of NNK and NNN + Cu2+ + NADPH generated relatively high rates of DNA oxidation. Lung is the exposure route in smoking and vaping, human lung tissue contains Cu2+ and NADPH, and lung microsomal enzymes gave the highest rates of DNA oxidation in this study. Also, E-cigarette vapor contains 6-fold more copper than that in cigarette smoke, which could exacerbate DNA oxidation.
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Affiliation(s)
- Rumasha N T Kankanamage
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Abhisek Brata Ghosh
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Di Jiang
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Karmel Gkika
- School of Chemical Sciences, Dublin City University, Dublin D9, Ireland
| | - Tia Keyes
- School of Chemical Sciences, Dublin City University, Dublin D9, Ireland
| | - Laura A Achola
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Steven Suib
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
- Institute of Material Science, Storrs, Connecticut 06269, United States
| | - James F Rusling
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
- Institute of Material Science, Storrs, Connecticut 06269, United States
- Department of Surgery and Neag Cancer Center, UConn Health, Farmington, Connecticut 06032, United States
- School of Chemistry, National University of Ireland at Galway, Galway H91 TK33, Ireland
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16
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Borrego-Soto G, Perez-Paramo YX, Chen G, Santuario-Facio SK, Santos-Guzman J, Posadas-Valay R, Alvarado-Monroy FM, Balderas-Renteria I, Medina-Gonzalez R, Ortiz-Lopez R, Lazarus P, Rojas-Martinez A. Genetic variants in CYP2A6 and UGT1A9 genes associated with urinary nicotine metabolites in young Mexican smokers. THE PHARMACOGENOMICS JOURNAL 2020; 20:586-594. [PMID: 31959879 PMCID: PMC7375952 DOI: 10.1038/s41397-020-0147-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 12/19/2019] [Accepted: 01/07/2020] [Indexed: 12/24/2022]
Abstract
Nicotine is the major pharmacologically active substance in tobacco. Several studies have examined genotypes related to nicotine metabolism, but few studies have been performed in the Mexican population. The objective was to identify associations between gene variants in metabolizing enzymes and the urinary levels of nicotine metabolites among Mexican smokers. The levels of nicotine and its metabolites were determined in the urine of 88 young smokers from Mexico, and 167 variants in 24 genes associated with nicotine metabolism were genotyped by next-generation sequencing (NGS). Trans-3'-hydroxy-cotinine (3HC) and 4-hydroxy-4-(3-pyridyl)-butanoic acid were the most abundant metabolites (35 and 17%, respectively). CYP2A6*12 was associated with 3HC (p = 0.014). The rs145014075 was associated with creatinine-adjusted levels of nicotine (p = 0.035), while the rs12471326 (UGT1A9) was associated to cotinine-N-glucuronide (p = 0.030). CYP2A6 and UGT1A9 variants are associated to nicotine metabolism. 4HPBA metabolite was an abundant urinary metabolite in young Mexican smokers.
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Affiliation(s)
- Gissela Borrego-Soto
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Monterrey, Mexico
| | - Yadira X Perez-Paramo
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | - Gang Chen
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | | | - Jesus Santos-Guzman
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Monterrey, Mexico
| | - Rodolfo Posadas-Valay
- Facultad de Medicina, Centro Universitario de Salud, Universidad Autonoma de Nuevo Leon, Monterrey, Mexico
| | | | | | - Ramses Medina-Gonzalez
- Centro de Investigación y Desarrollo en Ciencias de la Salud, Universidad Autonoma de Nuevo Leon, Monterrey, Mexico
| | - Rocio Ortiz-Lopez
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Monterrey, Mexico
| | - Philip Lazarus
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | - Augusto Rojas-Martinez
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Monterrey, Mexico.
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17
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Tai LC, Ahn CH, Nyein HYY, Ji W, Bariya M, Lin Y, Li L, Javey A. Nicotine Monitoring with a Wearable Sweat Band. ACS Sens 2020; 5:1831-1837. [PMID: 32429661 DOI: 10.1021/acssensors.0c00791] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The tobacco epidemic is a public health threat that has taken a heavy toll of lives around the globe each year. Smoking affects both the smokers and those who are exposed to secondhand smoke, and careful tracking of exposure can be key to mitigating the potential hazards. For smokers, the variation of chemical compositions between commercial cigarettes has led to ambiguity in estimating the health risks, both for active smokers and others involuntarily exposed to tobacco smoke and byproducts. In this regard, sweat possesses an attractive opportunity to monitor smoke exposure due to sweat's abundance in biomolecules and its great accessibility. Here, we present a wearable sweat band to monitor nicotine, a prominent ingredient in cigarettes, as a viable way to quantitatively assess a wearer's exposure to smoking. Both smokers and normal subjects are tested to demonstrate the use of this device for smoke-related health monitoring. Our results exhibit confirmable and elevated nicotine levels in sweat for subjects inhaling cigarette smoke. This continuous and personalized sweat sensing device is leverage to monitor smoke pollution for a potentially broad population.
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Affiliation(s)
- Li-Chia Tai
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
- Berkeley Sensor and Actuator Center, University of California, Berkeley, California 94720, United States
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Christine Heera Ahn
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
| | - Hnin Yin Yin Nyein
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
- Berkeley Sensor and Actuator Center, University of California, Berkeley, California 94720, United States
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Wenbo Ji
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
- Berkeley Sensor and Actuator Center, University of California, Berkeley, California 94720, United States
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Mallika Bariya
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
- Berkeley Sensor and Actuator Center, University of California, Berkeley, California 94720, United States
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Yuanjing Lin
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
- Berkeley Sensor and Actuator Center, University of California, Berkeley, California 94720, United States
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Lu Li
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Ali Javey
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
- Berkeley Sensor and Actuator Center, University of California, Berkeley, California 94720, United States
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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18
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Benowitz NL, St. Helen G, Nardone N, Cox LS, Jacob P. Urine Metabolites for Estimating Daily Intake of Nicotine From Cigarette Smoking. Nicotine Tob Res 2020; 22:288-292. [PMID: 30852610 PMCID: PMC7297087 DOI: 10.1093/ntr/ntz034] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 03/06/2019] [Indexed: 11/13/2022]
Abstract
INTRODUCTION Accurate measurement of nicotine exposure from cigarette smoke is important in studying disease risk and level of dependence. Urine total nicotine equivalents, the molar sum of nicotine and six metabolites (NE7), accounts for more than 90% of a nicotine dose and is independent of individual metabolic differences. However, measuring NE7 is technically difficult and costly. We compared NE7, the gold standard of nicotine intake, with different combinations of fewer urinary nicotine metabolites. We also examined the impact of individual differences in nicotine metabolic rate, sex, and race on strength of association with NE7. METHODS Urine samples from 796 daily smokers, who participated across five clinical studies, were assayed for nicotine and/or metabolites. Associations with NE7 were assessed by regression and Bland-Altman analyses. RESULTS Overall, the molar sum of urine [cotinine + 3'-hydroxycotinine (3HC)] (NE2) and [nicotine +
cotinine + 3HC] (NE3) were strongly correlated with NE7 (r = .97 and .99, respectively). However, in slow metabolizers NE2 was less predictive of NE7, whereas NE3 was equally robust. Urine total cotinine was also strongly correlated with NE7 (r = .87). CONCLUSIONS Urine NE3 is a robust biomarker of daily nicotine intake, independently of individual metabolic differences, whereas NE2 is less accurate in slow metabolizers. Our findings inform the selection of more rigorous and cost-effective measures to assess nicotine exposure in tobacco research studies. IMPLICATIONS The molar sum of urine total nicotine, cotinine and 3HC (NE3) is a robust biomarker of daily nicotine intake, independently of individual metabolic differences, and performs as well as measuring seven nicotine metabolites (NE7). The sum of cotinine and 3HC (NE2) is less accurate in slow metabolizers. Our findings inform the selection of more rigorous and cost-effective measures to assess nicotine exposure in tobacco research studies.
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Affiliation(s)
- Neal L Benowitz
- Division of Clinical Pharmacology, Department of Medicine, University of California, San Francisco, CA
- Center for Tobacco Control Research and Education, Department of Medicine, University of California, San Francisco, CA
| | - Gideon St. Helen
- Division of Clinical Pharmacology, Department of Medicine, University of California, San Francisco, CA
- Center for Tobacco Control Research and Education, Department of Medicine, University of California, San Francisco, CA
| | - Natalie Nardone
- Division of Clinical Pharmacology, Department of Medicine, University of California, San Francisco, CA
| | - Lisa Sanderson Cox
- Department of Preventive Medicine and Public Health, University of Kansas Medical School, Kansas City, KS
| | - Peyton Jacob
- Center for Tobacco Control Research and Education, Department of Medicine, University of California, San Francisco, CA
- Department of Psychiatry, University of California, San Francisco, CA
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19
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Jokić S, Gagić T, Knez Ž, Banožić M, Škerget M. Separation of active compounds from tobacco waste using subcritical water extraction. J Supercrit Fluids 2019. [DOI: 10.1016/j.supflu.2019.104593] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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20
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Thisted T, Biesova Z, Walmacq C, Stone E, Rodnick-Smith M, Ahmed SS, Horrigan SK, Van Engelen B, Reed C, Kalnik MW. Optimization of a nicotine degrading enzyme for potential use in treatment of nicotine addiction. BMC Biotechnol 2019; 19:56. [PMID: 31375100 PMCID: PMC6679477 DOI: 10.1186/s12896-019-0551-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 07/23/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Smoking and tobacco use continue to be the largest preventable causes of death globally. A novel therapeutic approach has recently been proposed: administration of an enzyme that degrades nicotine, the main addictive component of tobacco, minimizing brain exposure and reducing its reinforcing effects. Pre-clinical proof of concept has been previously established through dosing the amine oxidase NicA2 from Pseudomonas putida in rat nicotine self-administration models of addiction. RESULTS This paper describes efforts towards optimizing NicA2 for potential therapeutic use: enhancing potency, improving its pharmacokinetic profile, and attenuating immunogenicity. Libraries randomizing residues located in all 22 active site positions of NicA2 were screened. 58 single mutations with 2- to 19-fold enhanced catalytic activity compared to wt at 10 μM nicotine were identified. A novel nicotine biosensor assay allowed efficient screening of the many primary hits for activity at nicotine concentrations typically found in smokers. 10 mutants with improved activity in rat serum at or below 250 nM were identified. These catalytic improvements translated to increased potency in vivo in the form of further lowering of nicotine blood levels and nicotine accumulation in the brains of Sprague-Dawley rats. Examination of the X-ray crystal structure suggests that these mutants may accelerate the rate limiting re-oxidation of the flavin adenine dinucleotide cofactor by enhancing molecular oxygen's access. PEGylation of NicA2 led to prolonged serum half-life and lowered immunogenicity observed in a human HLA DR4 transgenic mouse model, without impacting nicotine degrading activity. CONCLUSIONS Systematic mutational analysis of the active site of the nicotine-degrading enzyme NicA2 has yielded 10 variants that increase the catalytic activity and its effects on nicotine distribution in vivo at nicotine plasma concentrations found in smokers. In addition, PEGylation substantially increases circulating half-life and reduces the enzyme's immunogenic potential. Taken together, these results provide a viable path towards generation of a drug candidate suitable for human therapeutic use in treating nicotine addiction.
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Affiliation(s)
- Thomas Thisted
- Antidote Therapeutics, Inc, 708 Quince Orchard Road, Suite 250-C, Gaithersburg, MD 20878 USA
| | - Zuzana Biesova
- Antidote Therapeutics, Inc, 708 Quince Orchard Road, Suite 250-C, Gaithersburg, MD 20878 USA
| | - Celine Walmacq
- Antidote Therapeutics, Inc, 708 Quince Orchard Road, Suite 250-C, Gaithersburg, MD 20878 USA
| | - Everett Stone
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX USA
| | - Max Rodnick-Smith
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX USA
| | - Shaheda S. Ahmed
- Alcyomics Ltd, Bulman House, Regent Centre, Gosforth, Newcastle upon Tyne, NE3 3LS UK
| | | | - Bo Van Engelen
- Antidote Therapeutics, Inc, 708 Quince Orchard Road, Suite 250-C, Gaithersburg, MD 20878 USA
- Maastricht University, P. Debyeplein 1, 6229 HA, Maastricht, NL USA
| | - Charles Reed
- Antidote Therapeutics, Inc, 708 Quince Orchard Road, Suite 250-C, Gaithersburg, MD 20878 USA
| | - Matthew W. Kalnik
- Antidote Therapeutics, Inc, 708 Quince Orchard Road, Suite 250-C, Gaithersburg, MD 20878 USA
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Xu Y, Zhang Q, Li P, Hong G, Wang D, Liu J, Zhou H, Chai G, Lu B, He S, Zhang W, Sun S, Zhang J, Mao J. Nicotine Pharmacokinetics in Rat Brain and Blood by Simultaneous Microdialysis, Stable-Isotope Labeling, and UHPLC–HRMS: Determination of Nicotine Metabolites. Anal Chem 2019; 91:2916-2922. [DOI: 10.1021/acs.analchem.8b05078] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Yan Xu
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Qidong Zhang
- Zhengzhou Tobacco Research Institute of China National Tobacco Company, Zhengzhou 450001, China
| | - Peng Li
- Zhengzhou Tobacco Research Institute of China National Tobacco Company, Zhengzhou 450001, China
| | - Guangfeng Hong
- Zhengzhou Tobacco Research Institute of China National Tobacco Company, Zhengzhou 450001, China
| | - Dingzhong Wang
- Zhengzhou Tobacco Research Institute of China National Tobacco Company, Zhengzhou 450001, China
| | - Junhui Liu
- Zhengzhou Tobacco Research Institute of China National Tobacco Company, Zhengzhou 450001, China
| | - Hao Zhou
- Technology Center, China Tobacco Henan Industrial Co., Ltd., Zhengzhou 450000, China
| | - Guobi Chai
- Zhengzhou Tobacco Research Institute of China National Tobacco Company, Zhengzhou 450001, China
| | - Binbin Lu
- Zhengzhou Tobacco Research Institute of China National Tobacco Company, Zhengzhou 450001, China
| | - Shengbao He
- China National Tobacco Quality Supervision and Test Center, Zhengzhou 450001, China
| | - Wenjuan Zhang
- Zhengzhou Tobacco Research Institute of China National Tobacco Company, Zhengzhou 450001, China
| | - Shihao Sun
- Zhengzhou Tobacco Research Institute of China National Tobacco Company, Zhengzhou 450001, China
| | - Jianxun Zhang
- Zhengzhou Tobacco Research Institute of China National Tobacco Company, Zhengzhou 450001, China
| | - Jian Mao
- Zhengzhou Tobacco Research Institute of China National Tobacco Company, Zhengzhou 450001, China
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22
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Jaccard G, Kondylis A, Gunduz I, Pijnenburg J, Belushkin M. Investigation and comparison of the transfer of TSNA from tobacco to cigarette mainstream smoke and to the aerosol of a heated tobacco product, THS2.2. Regul Toxicol Pharmacol 2018; 97:103-109. [PMID: 29928933 DOI: 10.1016/j.yrtph.2018.06.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 06/15/2018] [Accepted: 06/16/2018] [Indexed: 01/26/2023]
Abstract
Tobacco-specific nitrosamines (TSNA) levels in tobacco cut filler and cigarette smoke were measured in more than 1000 commercially available cigarettes sampled between 2008 and 2014. Relative contributions to their transfer from tobacco to the mainstream smoke in terms of direct transfer by distillation, pyrorelease, and pyrosynthesis were evaluated on the basis of the comparison with the transfer of nicotine from tobacco to smoke. N'-nitrosonornicotine (NNN) was transferred essentially by distillation, while N'-nitrosoanatabine (NAT), 4-(methylnitrosamino)-1-(3-bipyridyl)-1-butanone (NNK) and N'-nitrosoanabasine (NAB) were transferred by pyrorelease or pyrosynthesis as well. In the case of the Tobacco Heating System 2.2, the transfer of nicotine from tobacco to the aerosol was similar to that observed for cigarettes, while the % transfer of TSNAs from tobacco to THS 2.2 aerosol was 2-3 times lower than in cigarettes. This difference is due to the fact that the tobacco is heated instead of burnt resulting in a lower direct transfer by distillation and a lower if any contribution of pyrosynthesis or pyrorelease.
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Affiliation(s)
- Guy Jaccard
- PMI R&D, Philip Morris Products S.A., Part of Philip Morris International Group of Companies, Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland.
| | - Athanasios Kondylis
- PMI R&D, Philip Morris Products S.A., Part of Philip Morris International Group of Companies, Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland
| | - Irfan Gunduz
- Philip Morris International Management S.A., Part of Philip Morris International Group of Companies, Lausanne, Switzerland
| | - Johannes Pijnenburg
- PMI R&D, Philip Morris Products S.A., Part of Philip Morris International Group of Companies, Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland
| | - Maxim Belushkin
- PMI R&D, Philip Morris Products S.A., Part of Philip Morris International Group of Companies, Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland
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Abstract
OBJECTIVE The aim of this study is to use high-resolution metabolomics (HRM) to identify metabolic pathways and networks associated with tobacco use in military personnel. METHODS Four hundred deidentified samples obtained from the Department of Defense Serum Repository were classified as tobacco users or nonusers according to cotinine content. HRM and bioinformatic methods were used to determine pathways and networks associated with classification. RESULTS Eighty individuals were classified as tobacco users compared with 320 nonusers on the basis of cotinine levels at least 10 ng/mL. Alterations in lipid and xenobiotic metabolism, and diverse effects on amino acid, sialic acid, and purine and pyrimidine metabolism were observed. Importantly, network analysis showed broad effects on metabolic associations not simply linked to well-defined pathways. CONCLUSIONS Tobacco use has complex metabolic effects that must be considered in evaluation of deployment-associated environmental exposures in military personnel.
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24
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Lian L, Yan S, Yao B, Chan SA, Song W. Photochemical Transformation of Nicotine in Wastewater Effluent. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:11718-11730. [PMID: 28942634 DOI: 10.1021/acs.est.7b03223] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Nicotine is a highly toxic tobacco alkaloid that is ubiquitous in wastewater effluent. For the first time, we report the identification of the products and the pathways for the photodegradation of nicotine in an effluent matrix under simulated solar irradiation. Nicotine was found to be degraded by triplet-state organic matter (3OM*), thus indicating that electron transfer is a preferred reaction mechanism. Using the multivariate statistical strategies orthogonal projection to latent structures discriminant analysis (OPLS-DA) and hierarchical clustering, 49 potential transformation products (TPs) of nicotine were successfully extracted from the water matrix via high-resolution ultrahigh-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS). Overall, 30 TPs, including 4 groups of nonseparated isomeric photo TPs, were identified with various levels of confidence based on the tandem mass spectrometry information on standard compounds and the isotope-labeling method (using rac-nicotine-2',3',3'-D3, rac-nicotine-13CD3, and rac-nicotine-D4) under air-saturated conditions. The pyrrolidine ring of nicotine was found to be the reactive site under sunlight irradiation. Pseudooxynicotine was the main primary TP from nicotine, with a maximum transformation ratio of 64%. Nicotinic acid, cotinine, 3'-hydroxycotinine, and myosmine were the final stable TPs after 72 h of solar irradiation, with yields of 13%, 3%, 5%, and 5%, respectively.
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Affiliation(s)
- Lushi Lian
- Department of Environmental Science and Engineering, Fudan University , Shanghai 200433, China
| | - Shuwen Yan
- Department of Environmental Science and Engineering, Fudan University , Shanghai 200433, China
| | - Bo Yao
- Department of Environmental Science and Engineering, Fudan University , Shanghai 200433, China
| | - Shen-An Chan
- Agilent Technology, Inc. , 1350 North Sichuan Road, Shanghai 200080, PR China
| | - Weihua Song
- Department of Environmental Science and Engineering, Fudan University , Shanghai 200433, China
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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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Periplasmic Nicotine Dehydrogenase NdhAB Utilizes Pseudoazurin as Its Physiological Electron Acceptor in Agrobacterium tumefaciens S33. Appl Environ Microbiol 2017. [PMID: 28625985 DOI: 10.1128/aem.01050-17] [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] [Indexed: 11/20/2022] Open
Abstract
Agrobacterium tumefaciens S33 can grow with nicotine as the sole source of carbon, nitrogen, and energy via a novel hybrid of the pyridine pathway and the pyrrolidine pathway. Characterization of the enzymes involved in the hybrid pathway is important for understanding its biochemical mechanism. Here, we report that the molybdenum-containing nicotine dehydrogenase (NdhAB), which catalyzes the initial step of nicotine degradation, is located in the periplasm of strain S33, while the 6-hydroxynicotine oxidase and 6-hydroxypseudooxynicoine oxidase are in the cytoplasm. This is consistent with the fact that NdhA has a Tat signal peptide. Interestingly, an open reading frame (ORF) adjacent to the ndhAB gene was verified to encode a copper-containing electron carrier, pseudoazurin (Paz), which has a signal peptide typical of bacterial Paz proteins. Both were transported into the periplasm after being produced in the cytoplasm. We purified NdhAB from the periplasmic fraction of strain S33 and found that with Paz as the physiological electron acceptor, NdhAB catalyzed the hydroxylation of nicotine at a specific rate of 110.52 ± 8.09 μmol · min-1 · mg of protein-1, where the oxygen atom in the hydroxyl group of the product 6-hydroxynicotine was derived from H2O. The apparent Km values for nicotine and Paz were 1.64 ± 0.07 μM and 3.61 ± 0.23 μM, respectively. NAD(P)+, O2, and ferredoxin could not serve as electron acceptors. Disruption of the paz gene disabled the strain for nicotine degradation, indicating that Paz is required for nicotine catabolism in the strain. These findings help our understanding of electron transfer during nicotine degradation in bacteria.IMPORTANCE Nicotine is a toxic and addictive N-heterocyclic aromatic alkaloid produced in tobacco. Its catabolism in organisms and degradation in tobacco wastes have become major concerns for human health and the environment. Bacteria usually decompose nicotine using the classical strategy of hydroxylating the pyridine ring with the help of activated oxygen by nicotine dehydrogenase, which binds one molybdopterin, two [2Fe2S] clusters, and usually one flavin adenine dinucleotide (FAD) as well. However, the physiological electron acceptor for the reaction is still unknown. In this study, we found that the two-component nicotine dehydrogenase from Agrobacterium tumefaciens S33, naturally lacking an FAD-binding domain, is located in the periplasmic space and uses a copper-containing electron carrier, pseudoazurin, as its physiological electron acceptor. We report here the role of pseudoazurin in a reaction catalyzed by a molybdopterin-containing hydroxylase occurring in the periplasmic space. These results provide new biochemical knowledge on microbial degradation of N-heterocyclic aromatic compounds.
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27
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E-cigarettes induce toxicological effects that can raise the cancer risk. Sci Rep 2017; 7:2028. [PMID: 28515485 PMCID: PMC5435699 DOI: 10.1038/s41598-017-02317-8] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 04/10/2017] [Indexed: 11/08/2022] Open
Abstract
Electronic cigarettes (e-cigs) are devices designed to deliver nicotine in a vaping solution rather than smoke and without tobacco combustion. Perceived as a safer alternative to conventional cigarettes, e-cigs are aggressively marketed as lifestyle-choice consumables, thanks to few restrictions and a lack of regulatory guidelines. E-cigs have also gained popularity among never-smokers and teenagers, becoming an emergent public health issue. Despite the burgeoning worldwide consumption of e-cigs, their safety remains largely unproven and it is unknown whether these devices cause in vivo toxicological effects that could contribute to cancer. Here we demonstrate the co-mutagenic and cancer-initiating effects of e-cig vapour in a rat lung model. We found that e-cigs have a powerful booster effect on phase-I carcinogen-bioactivating enzymes, including activators of polycyclic aromatic hydrocarbons (PAHs), and increase oxygen free radical production and DNA oxidation to 8-hydroxy-2'-deoxyguanosine. Furthermore, we found that e-cigs damage DNA not only at chromosomal level in peripheral blood, such as strand breaks in leucocytes and micronuclei formation in reticulocytes, but also at gene level such as point mutations in urine. Our results demonstrate that exposure to e-cigs could endanger human health, particularly among younger more vulnerable consumers.
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28
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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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29
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Barley RDC, Pollock S, Shallow MC, Peters E, Lam EWN. Tobacco-related-compound-induced Nitrosative Stress Injury in the Hamster Cheek Pouch. J Dent Res 2016; 83:903-8. [PMID: 15557395 DOI: 10.1177/154405910408301203] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The nitric oxide radical (•NO) released from tobacco-related compounds induces DNA damage, protein modifications, and cellular toxicity through the formation of peroxynitrite (ONOO−), the reaction product of •NO and the oxygen radical, superoxide. We hypothesize that tobacco-related compounds are cytotoxic and induce quantifiable DNA single-strand breaks in immortalized hamster cheek pouch (POII) cells, and that an amino acid marker of ONOO− injury, namely, 3-nitrotyrosine (3-NT), is detectable in hamster cheek pouch tissues chronically exposed to these compounds. We observed a dose-dependent decrease in POII cell viability with increasing tobacco-related compound concentrations, as well as a dose-dependent increase in DNA strand breaks. Semi-quantitative immunohistochemistry showed intense 3-NT immunoreactivity in hamster tissues treated with tobacco-related compounds compared with controls (p < 0.005). Our results suggest that tobacco-related compounds, including nicotine, are genotoxic, and that 3-NT is a quantifiable marker of ONOO− damage in intact hamster cheek pouch tissues.
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Affiliation(s)
- R D C Barley
- Division of Oral & Maxillofacial Radiology, Department of Dentistry, Faculty of Medicine and Dentistry, University of Alberta, DPC 2085, Edmonton, AB T6G 2N8, Canada
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30
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Nicotine versus 6-hydroxy-l-nicotine against chlorisondamine induced memory impairment and oxidative stress in the rat hippocampus. Biomed Pharmacother 2016; 86:102-108. [PMID: 27951416 DOI: 10.1016/j.biopha.2016.12.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 11/28/2016] [Accepted: 12/04/2016] [Indexed: 11/21/2022] Open
Abstract
6-Hydroxy-l-nicotine (6HLN), a nicotine derivative from nicotine degradation by Arthrobacter nicotinovorans pAO1 strain was found to improve behavioral deficits and to reverse oxidative stress in the rat hippocampus. Rats were given CHL (10mg/kg, i.p.) were used as an Alzheimer's disease-like model. The nicotine (0.3mg/kg) and 6HLN (0.3mg/kg) were administered alone or in combination in the CHL-treated rats. Memory-related behaviors were evaluated using Y-maze and radial arm-maze tests. The antioxidant enzymes activity and the levels of the biomarkers of oxidative stress were measured in the hippocampus. Statistical analyses were performed using two-way ANOVA and Tukey's post hoc test. F values for which p<0.05 were regarded as statistically significant. CHL-caused memory deficits and oxidative stress enhancing were observed. Both nicotine and 6HLN administration attenuated the cognitive deficits and recovered the antioxidant capacity in the rat hippocampus of the CHL rat model. Our results suggest that 6HLN versus nicotine confers anti-amnesic properties in the CHL-induced a rat model of memory impairment via reversing cholinergic function and decreasing brain oxidative stress, suggesting the use of this compound as an alternative agent in AD treatment.
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31
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Dupont P, Benyamina A, Aubin HJ. Sécurité d’emploi de la nicotine au long cours : le débat n’est pas clos. Rev Mal Respir 2016; 33:892-898. [DOI: 10.1016/j.rmr.2016.05.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 11/07/2015] [Indexed: 02/02/2023]
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32
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Gong X, Ma G, Duan Y, Zhu D, Chen Y, Zhang KQ, Yang J. Biodegradation and metabolic pathway of nicotine in Rhodococcus sp. Y22. World J Microbiol Biotechnol 2016; 32:188. [PMID: 27677748 DOI: 10.1007/s11274-016-2147-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 09/22/2016] [Indexed: 10/20/2022]
Abstract
Nicotine in tobacco is harmful to health and the environment, so there is an environmental requirement to remove nicotine from tobacco and tobacco wastes. In this study, the biotransformation of nicotine by Rhodococcus sp. Y22 was investigated, and three metabolites (NIC1, NIC4 and NIC5) were isolated by column separation, preparative TLC and solid plate's method, respectively. NIC1 was identified as 6-hydoxynicotine based on the results of NMR, MS, HPLC-UV and HRESIMS analysis; NIC4 was a novel compound and identified as 5-(3-methyl-[1,3]oxazinan-2-ylidene)-5H-pyridin-2-one based on the results of NMR, MS and UV analysis; NIC5 was identified as nicotine blue based on the results of NMR and MS analysis. Meanwhile, two metabolites NIC2 and NIC3 were identified as 6-hydroxy-N-methylmyosmine and 6-hydroxypseudooxynicotine by HRESIMS analysis, respectively. According to these metabolites, the possible pathway of nicotine degradation by Rhodococcus sp. Y22 was proposed. The nicotine can be transformed to nicotine blue through two pathways (A and B), and 6-hydroxy-N-methylmyosmine is the key compound, which can be converted to 6-hydroxypseudooxynicotine (pathway A) and 5-(3-methyl-[1,3]oxazinan-2-ylidene)-5H-pyridin-2-one (pathway B), respectively. Moreover, the encoding gene of nicotine dehydrogenase, ndh, was amplified from Rhodococcus sp. Y22, and its transcriptional level could be up-regulated obviously under nicotine induction. Our studies reported the key metabolites and possible biotransformation pathway of nicotine in Rhodococcus sp. Y22, and provided new insights into the microbial metabolism of nicotine.
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Affiliation(s)
- Xiaowei Gong
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, People's Republic of China
- R & D Center of China Tobacco Yunnan Industrial Co., Ltd., Kunming, 650024, People's Republic of China
| | - Guanghui Ma
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, People's Republic of China
- Yunnan Comtestor Co., Ltd., Kunming, 650106, People's Republic of China
| | - Yanqing Duan
- R & D Center of China Tobacco Yunnan Industrial Co., Ltd., Kunming, 650024, People's Republic of China
| | - Donglai Zhu
- R & D Center of China Tobacco Yunnan Industrial Co., Ltd., Kunming, 650024, People's Republic of China
| | - Yongkuan Chen
- R & D Center of China Tobacco Yunnan Industrial Co., Ltd., Kunming, 650024, People's Republic of China
| | - Ke-Qin Zhang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, People's Republic of China
| | - Jinkui Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, People's Republic of China.
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33
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Yalcin E, de la Monte S. Tobacco nitrosamines as culprits in disease: mechanisms reviewed. J Physiol Biochem 2016; 72:107-20. [PMID: 26767836 PMCID: PMC4868960 DOI: 10.1007/s13105-016-0465-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 01/05/2016] [Indexed: 12/29/2022]
Abstract
The link between tobacco abuse and cancer is well-established. However, emerging data indicate that toxins in tobacco smoke cause cellular injury due to enhanced toxic/metabolic effects of metabolites, disruption of intracellular signaling mechanisms, and formation of DNA, protein, and lipid adducts that impair function and promote oxidative stress and inflammation. These effects of smoking, which are largely non-carcinogenic, can be produced by tobacco-specific nitrosamines and their metabolites. These factors could account for the increased rates of neurodegeneration and insulin resistance diseases among smokers. Herein, we review nicotine and tobacco-specific nitrosamine metabolism, mechanisms of adduct formation, DNA damage, mutagenesis, and potential mechanisms of disease.
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Affiliation(s)
- Emine Yalcin
- Departments of Pathology (Neuropathology), Neurology, and Medicine, Rhode Island Hospital and the Warren Alpert Medical School of Brown University, 55 Claverick Street, Room 419, Providence, RI, 02903, USA
| | - Suzanne de la Monte
- Departments of Pathology (Neuropathology), Neurology, and Medicine, Rhode Island Hospital and the Warren Alpert Medical School of Brown University, 55 Claverick Street, Room 419, Providence, RI, 02903, USA.
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34
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Xue S, Schlosburg JE, Janda KD. A New Strategy for Smoking Cessation: Characterization of a Bacterial Enzyme for the Degradation of Nicotine. J Am Chem Soc 2015; 137:10136-9. [DOI: 10.1021/jacs.5b06605] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Song Xue
- Departments of Chemistry
and Immunology and The Skaggs Institute
for Chemical Biology, and ‡Worm Institute for Research and Medicine (WIRM), The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Joel E. Schlosburg
- Departments of Chemistry
and Immunology and The Skaggs Institute
for Chemical Biology, and ‡Worm Institute for Research and Medicine (WIRM), The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Kim D. Janda
- Departments of Chemistry
and Immunology and The Skaggs Institute
for Chemical Biology, and ‡Worm Institute for Research and Medicine (WIRM), The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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35
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Ande A, McArthur C, Ayuk L, Awasom C, Achu PN, Njinda A, Sinha N, Rao PSS, Agudelo M, Nookala AR, Simon S, Kumar A, Kumar S. Effect of mild-to-moderate smoking on viral load, cytokines, oxidative stress, and cytochrome P450 enzymes in HIV-infected individuals. PLoS One 2015; 10:e0122402. [PMID: 25879453 PMCID: PMC4399877 DOI: 10.1371/journal.pone.0122402] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 02/21/2015] [Indexed: 01/05/2023] Open
Abstract
Mild-to-moderate tobacco smoking is highly prevalent in HIV-infected individuals, and is known to exacerbate HIV pathogenesis. The objective of this study was to determine the specific effects of mild-to-moderate smoking on viral load, cytokine production, and oxidative stress and cytochrome P450 (CYP) pathways in HIV-infected individuals who have not yet received antiretroviral therapy (ART). Thirty-two human subjects were recruited and assigned to four different cohorts as follows: a) HIV negative non-smokers, b) HIV positive non-smokers, c) HIV negative mild-to-moderate smokers, and d) HIV positive mild-to-moderate smokers. Patients were recruited in Cameroon, Africa using strict selection criteria to exclude patients not yet eligible for ART and not receiving conventional or traditional medications. Those with active tuberculosis, hepatitis B or with a history of substance abuse were also excluded. Our results showed an increase in the viral load in the plasma of HIV positive patients who were mild-to-moderate smokers compared to individuals who did not smoke. Furthermore, although we did not observe significant changes in the levels of most pro-inflammatory cytokines, the cytokine IL-8 and MCP-1 showed a significant decrease in the plasma of HIV-infected patients and smokers compared with HIV negative non-smokers. Importantly, HIV-infected individuals and smokers showed a significant increase in oxidative stress compared with HIV negative non-smoker subjects in both plasma and monocytes. To examine the possible pathways involved in increased oxidative stress and viral load, we determined the mRNA levels of several antioxidant and cytochrome P450 enzymes in monocytes. The results showed that the levels of most antioxidants are unaltered, suggesting their inability to counter oxidative stress. While CYP2A6 was induced in smokers, CYP3A4 was induced in HIV and HIV positive smokers compared with HIV negative non-smokers. Overall, the findings suggest a possible association of oxidative stress and perhaps CYP pathway with smoking-mediated increased viral load in HIV positive individuals.
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Affiliation(s)
- Anusha Ande
- Division of Pharmacology and Toxicology, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri, United States of America
| | - Carole McArthur
- Department of Oral and Craniofacial Science, School of Dentistry, University of Missouri-Kansas City, Kansas City, Missouri, United States of America
| | - Leo Ayuk
- Regional Hospital, Box 818, Bamenda, North West Province, Cameroon
| | - Charles Awasom
- Regional Hospital, Box 818, Bamenda, North West Province, Cameroon
| | - Paul Ngang Achu
- Mezam Polyclinic HIV/AIDS Treatment Center, Bamenda, Cameroon
| | - Annette Njinda
- Mezam Polyclinic HIV/AIDS Treatment Center, Bamenda, Cameroon
| | - Namita Sinha
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - P. S. S. Rao
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Marisela Agudelo
- Department of Immunology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, United States of America
| | - Anantha Ram Nookala
- Division of Pharmacology and Toxicology, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri, United States of America
| | - Stephen Simon
- Department of Medical Informatics, School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, United States of America
| | - Anil Kumar
- Division of Pharmacology and Toxicology, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri, United States of America
| | - Santosh Kumar
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
- * E-mail:
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Abstract
An aversive abstinence syndrome manifests 4-24 h following cessation of chronic use of nicotine-containing products. Symptoms peak on approximately the 3rd day and taper off over the course of the following 3-4 weeks. While the severity of withdrawal symptoms is largely determined by how nicotine is consumed, certain short nucleotide polymorphisms (SNPs) have been shown to predispose individuals to consume larger amounts of nicotine more frequently--as well as to more severe symptoms of withdrawal when trying to quit. Additionally, rodent behavioral models and transgenic mouse models have revealed that specific nicotinic acetylcholine receptor (nAChR) subunits, cellular components, and neuronal circuits are critical to the expression of withdrawal symptoms. Consequently, by continuing to map neuronal circuits and nAChR subpopulations that underlie the nicotine withdrawal syndrome--and by continuing to enumerate genes that predispose carriers to nicotine addiction and exacerbated withdrawal symptoms--it will be possible to pursue personalized therapeutics that more effectively treat nicotine addiction.
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Affiliation(s)
- Ian McLaughlin
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
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Not only smoking is deadly: fatal ingestion of e-juice—a case report. Int J Legal Med 2014; 129:481-6. [DOI: 10.1007/s00414-014-1086-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 09/08/2014] [Indexed: 11/26/2022]
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Bolleddula J, DeMent K, Driscoll JP, Worboys P, Brassil PJ, Bourdet DL. Biotransformation and bioactivation reactions of alicyclic amines in drug molecules. Drug Metab Rev 2014; 46:379-419. [DOI: 10.3109/03602532.2014.924962] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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McKinney DL, Frost-Pineda K, Oldham MJ, Fisher MT, Wang J, Gogova M, Kobal G. Cigarettes with different nicotine levels affect sensory perception and levels of biomarkers of exposure in adult smokers. Nicotine Tob Res 2014; 16:948-60. [PMID: 24638852 DOI: 10.1093/ntr/ntu009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
INTRODUCTION Few clinical studies involving cigarettes have provided a comprehensive picture of smoke exposure, test article characterization, and insights into sensory properties combined. The purpose of these pilot studies was to determine whether cigarettes with different levels of nicotine but similar tar levels would affect sensory experience or smoking behavior so as to significantly alter levels of selected biomarkers of exposure (BOE). METHODS In 2 confined, double-blind studies, 120 adult smokers switched from Marlboro Gold cigarettes at baseline to either 1 of 2 lower nicotine cigarettes or 1 of 2 higher nicotine cigarettes and then to the other cigarette after 5 days. Urinary excretion of exposure biomarkers (nicotine equivalents [NE], total and free 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol [NNAL], 1-hydroxypyrene, and 3-hydroxypropyl mercapturic acid) as well as carboxyhemoglobin and plasma cotinine were measured at baseline, Day 5, and Day 10. Daily cigarette consumption was monitored and sensory characteristics were rated for each cigarette. RESULTS With higher nicotine yield, urine NE, urine total NNAL, and plasma cotinine increased while nonnicotine BOE decreased without changes in cigarette consumption. In contrast, with lower nicotine yield, urine NE, urine total NNAL, and plasma cotinine dropped while nonnicotine BOE and cigarettes per day increased. Higher nicotine cigarettes were rated harsher and stronger than at baseline while lower nicotine cigarettes were less strong. All 4 test cigarettes were highly disliked. CONCLUSIONS These studies demonstrate that abrupt increases or decreases in nicotine and the resulting sensory changes impact BOE through changes in intensity or frequency of smoking.
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Simple, fast and sensitive LC–MS/MS analysis for the simultaneous quantification of nicotine and 10 of its major metabolites. J Chromatogr B Analyt Technol Biomed Life Sci 2014; 951-952:7-15. [DOI: 10.1016/j.jchromb.2014.01.025] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 01/03/2014] [Accepted: 01/10/2014] [Indexed: 11/19/2022]
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Gurusamy R, Natarajan S. Current status on biochemistry and molecular biology of microbial degradation of nicotine. ScientificWorldJournal 2013; 2013:125385. [PMID: 24470788 PMCID: PMC3891541 DOI: 10.1155/2013/125385] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2013] [Accepted: 10/14/2013] [Indexed: 11/30/2022] Open
Abstract
Bioremediation is one of the most promising methods to clean up polluted environments using highly efficient potent microbes. Microbes with specific enzymes and biochemical pathways are capable of degrading the tobacco alkaloids including highly toxic heterocyclic compound, nicotine. After the metabolic conversion, these nicotinophilic microbes use nicotine as the sole carbon, nitrogen, and energy source for their growth. Various nicotine degradation pathways such as demethylation pathway in fungi, pyridine pathway in Gram-positive bacteria, pyrrolidine pathway, and variant of pyridine and pyrrolidine pathways in Gram-negative bacteria have been reported. In this review, we discussed the nicotine-degrading pathways of microbes and their enzymes and biotechnological applications of nicotine intermediate metabolites.
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Affiliation(s)
- Raman Gurusamy
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Puducherry 605014, India
| | - Sakthivel Natarajan
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Puducherry 605014, India
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Earla R, Ande A, McArthur C, Kumar A, Kumar S. Enhanced nicotine metabolism in HIV-1-positive smokers compared with HIV-negative smokers: simultaneous determination of nicotine and its four metabolites in their plasma using a simple and sensitive electrospray ionization liquid chromatography-tandem mass spectrometry technique. Drug Metab Dispos 2013; 42:282-93. [PMID: 24301609 DOI: 10.1124/dmd.113.055186] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Smoking is approximately three times more prevalent in HIV-1-positive than HIV-negative individuals in the United States. Nicotine, which is the major constituent of tobacco, is rapidly metabolized mainly by cytochrome P450 (CYP2A6) to many metabolites. In this study, we developed a simple, fast, and sensitive electrospray ionization liquid chromatography-tandem mass spectrometry method using a strong cation solid phase extraction, and determined the concentration of nicotine and its four major metabolites (cotinine, nornicotine, norcotinine, and trans-3'-hydroxycotinine) in the plasma of HIV-1-positive and HIV-negative smokers. The multiple reaction monitoring transitions for nicotine, cotinine, trans-3'-hydroxycotinine, nornicotine, norcotinine, nicotine-d4, and cotinine-d3 were selected at mass-to-charge ratios of 163.3/117.1, 177.5/80.3, 193.2/80.1, 149.5/132.3, 163.4/80.3, 167.3/121.4, and 180.3/101.2, respectively. The lower limit of quantitation for nicotine and its metabolites was 0.53 ng/ml, which is relatively more sensitive than those previously reported. The concentration of nicotine was detected 5-fold lower in HIV-1-positive smokers (7.17 ± 3.8 ng/ml) than that observed in HIV-negative smokers (33.29 ± 15.4 ng/ml), whereas the concentration of the metabolite nornicotine was 3-fold higher in HIV-1-positive smokers (6.8 ± 2.9 ng/ml) than in HIV-negative smokers (2.3 ± 1.2 ng/ml). Although it was statistically nonsignificant, the concentration of the metabolite cotinine was also higher in HIV-1-positive smokers (85.6 ± 60.5 ng/ml) than in HIV-negative smokers (74.9 ± 40.5 ng/ml). In conclusion, a decrease in the concentration of nicotine and an increase in the concentration of its metabolites in HIV-1-positive smokers compared with HIV-negative smokers support the hypothesis that nicotine metabolism is enhanced in HIV-1-positive smokers compared with HIV-negative smokers.
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Affiliation(s)
- Ravinder Earla
- School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri (R.E., A.A., A.K., S.K.); and Department of Oral and Craniofacial Science, School of Dentistry, University of Missouri-Kansas City, Kansas City, Missouri (C.M.)
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43
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Raman G, Mohan K, Manohar V, Sakthivel N. Biodegradation of nicotine by a novel nicotine-degrading bacterium, Pseudomonas plecoglossicida TND35 and its new biotransformation intermediates. Biodegradation 2013; 25:95-107. [DOI: 10.1007/s10532-013-9643-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Accepted: 04/12/2013] [Indexed: 10/26/2022]
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44
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Hsu PC, Zhou B, Zhao Y, Ressom H, Cheema AK, Pickworth W, Shields PG. Feasibility of identifying the tobacco-related global metabolome in blood by UPLC-QTOF-MS. J Proteome Res 2013; 12:679-91. [PMID: 23240883 PMCID: PMC3579455 DOI: 10.1021/pr3007705] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Indexed: 11/30/2022]
Abstract
Metabolomics is likely an ideal tool to assess tobacco smoke exposure and the impact of cigarette smoke on human exposure and health. To assess reproducibility and feasibility of this by UPLC-QTOF-MS, three experiments were designed for the assessment of smokers' blood. Experiment I was an analysis of 8 smokers with 8 replicates. Experiment II was an analysis of 62 pooled quality control (QC) samples from 7 nonsmokers' plasma placed as every tenth sample among a study of 613 samples from 160 smokers. Finally, to examine the feasibility of metabolomic study in assessing smoke exposure, Experiment III consisted of 9 smokers and 10 nonsmokers' serum to evaluate differences in their global metabolome. There was minimal measurement and sample preparation variation in all experiments, although some caution is needed when analyzing specific parts of the chromatogram. When assessing QC samples in the large scale study, QC clustering indicated high stability, reproducibility, and consistency. Finally, in addition to the identification of nicotine metabolites as expected, there was a characteristic profile distinguishing smokers from nonsmokers. Metabolites selected from putative identifications were verified by MS/MS, showing the potential to identify metabolic phenotypes and new metabolites relating to cigarette smoke exposure and toxicity.
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Affiliation(s)
- Ping-Ching Hsu
- The Ohio State
University Comprehensive Cancer Center, Columbus, Ohio,
United States
| | - Bin Zhou
- Lombardi Comprehensive
Cancer
Center, Georgetown University, Washington,
D.C., United States
| | - Yi Zhao
- Lombardi Comprehensive
Cancer
Center, Georgetown University, Washington,
D.C., United States
| | - Habtom
W. Ressom
- Lombardi Comprehensive
Cancer
Center, Georgetown University, Washington,
D.C., United States
| | - Amrita K. Cheema
- Lombardi Comprehensive
Cancer
Center, Georgetown University, Washington,
D.C., United States
| | - Wallace Pickworth
- Battelle Centers
for Public Health Research & Evaluation, Baltimore,
Maryland, United States
| | - Peter G. Shields
- The Ohio State
University Comprehensive Cancer Center, Columbus, Ohio,
United States
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45
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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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46
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OPRM1 genetic polymorphisms are associated with the plasma nicotine metabolite cotinine concentration in methadone maintenance patients: a cross sectional study. J Hum Genet 2012; 58:84-90. [DOI: 10.1038/jhg.2012.139] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Ande A, Earla R, Jin M, Silverstein PS, Mitra AK, Kumar A, Kumar S. An LC-MS/MS method for concurrent determination of nicotine metabolites and the role of CYP2A6 in nicotine metabolite-mediated oxidative stress in SVGA astrocytes. Drug Alcohol Depend 2012; 125:49-59. [PMID: 22498344 PMCID: PMC3413753 DOI: 10.1016/j.drugalcdep.2012.03.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Revised: 03/15/2012] [Accepted: 03/16/2012] [Indexed: 11/28/2022]
Abstract
BACKGROUND Nicotine is known to generate oxidative stress through cytochrome P450 2A6 (CYP2A6)-mediated metabolism in the liver and other organs, including macrophages. This study has been designed to examine the role of CYP2A6 in nicotine metabolism and oxidative stress in SVGA cells, an immortalized human astrocyte cell line. METHODS SVGA astrocytes were treated with 1 μM nicotine, followed by determination of mRNA and protein levels of several CYPs using quantitative RT-PCR and western blot analyses, respectively. Quantitation of nicotine and the nicotine metabolites, cotinine and nicotine-derived nitrosamine ketones (NNK), was performed using an LC-MS/MS method. The generation of reactive oxygen species (ROS) was measured using flow cytometry. RESULTS Nicotine significantly upregulated mRNA and protein expression of the most abundantly expressed CYPs in SVGA astrocytes, CYP2A6 and CYP1A1. To characterize the metabolism of nicotine in astrocytes, a highly sensitive LC-MS/MS method was developed which is capable of quantifying very low concentrations of nicotine (0.3 ng/mL), cotinine and NNK (0.11 ng/mL). The LC-MS/MS results showed that nicotine is steadily metabolized to cotinine and NNK from 0.5 to 4h. Finally, we showed that nicotine initially causes an increase in ROS formation which is then gradually decreased, perhaps due to the increase in superoxide dismutase level. Nicotine metabolism and ROS formation by CYP2A6 were further confirmed by using tryptamine, a selective inhibitor of CYP2A6, which significantly lowered the levels of cotinine and NNK and inhibited ROS formation. CONCLUSIONS CYP2A6 plays a key role in nicotine metabolism and oxidative stress in astrocytes, and this has implications in nicotine-associated brain toxicity.
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Affiliation(s)
- Anusha Ande
- Pharmacology and Toxicology, School of Pharmacy, 3253 Health Sciences Building, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA
| | - Ravinder Earla
- Pharmaceutical Sciences, School of Pharmacy, 5258 Health Sciences Building, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA
| | - Mengyao Jin
- Pharmacology and Toxicology, School of Pharmacy, 3253 Health Sciences Building, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA
| | - Peter S Silverstein
- Pharmacology and Toxicology, School of Pharmacy, 3253 Health Sciences Building, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA
| | - Ashim K Mitra
- Pharmaceutical Sciences, School of Pharmacy, 5258 Health Sciences Building, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA
| | - Anil Kumar
- Pharmacology and Toxicology, School of Pharmacy, 3253 Health Sciences Building, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA
| | - Santosh Kumar
- Pharmacology and Toxicology, School of Pharmacy, 3253 Health Sciences Building, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA,Corresponding author: Division of Pharmacology and Toxicology, School of Pharmacy, University of Missouri-Kansas City, 2464 Charlotte St. Kansas City, MO 64108, USA Phone: 816-235-5494, Fax: 816-235-1776,
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48
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Williams JM, Gandhi KK, Lu SE, Steinberg ML, Benowitz NL. Nicotine intake and smoking topography in smokers with bipolar disorder. Bipolar Disord 2012; 14:618-27. [PMID: 22938167 PMCID: PMC3641517 DOI: 10.1111/j.1399-5618.2012.01047.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Cigarette smoking behavior in bipolar disorder (BPD), including the effects of mood-stabilizing medications, has not been well characterized. METHODS We compared serum nicotine, nicotine metabolite levels, and smoking topography in 75 smokers with BPD to 86 control smokers (CON). For some comparisons, an additional control group of 75 smokers with schizophrenia (SCZ) were included. RESULTS There were no differences between the BPD and CON groups in baseline smoking characteristics or serum nicotine or cotinine levels. Fifty-one smokers with BPD (68.9%) were taking one of the following mood stabilizers: valproic acid, lamotrigine, carbamazepine, oxcarbazepine, lithium, or topiramate. The 3-hydroxycotinine-to-cotinine ratio, a marker of cytochrome P450 2A6 (CYP2A6) metabolic activity, was significantly higher in BPD versus CON and versus SCZ (0.68 versus 0.49 versus 0.54; p =0.002). The difference between groups, however, was no longer significant when the analysis was repeated with those taking hepatic enzyme-inducing drugs (carbamazepine, oxcarbazepine, and topiramate) included as a covariate. The time between puffs, or interpuff interval (IPI), was shorter in BPD versus CON by an average of 3.0sec (p<0.05), although this was no longer significant when we removed smokers from the analysis of those taking hepatic enzyme inducers. CONCLUSIONS Smokers with BPD are not different from CON on most measures of nicotine intake and smoking topography. We found an increased rate of nicotine metabolism in smokers taking mood stabilizers that are hepatic enzyme inducers, including carbamazepine, oxcarbazepine, and topiramate. Smokers with rapid nicotine metabolism might be expected to smoke more intensely to compensate for the more rapid disappearance of nicotine from the blood and brain, and may have more difficulty in quitting smoking, although this requires further study.
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Affiliation(s)
- Jill M Williams
- University of Medicine and Dentistry of New Jersey (UMDNJ)-Robert Wood Johnson Medical School, New Brunswick, NJ 08901-2008, USA.
| | - Kunal K Gandhi
- UMDNJ–School of Public Health, New Brunswick, NJ,GlaxoSmithKline
| | - Shou-En Lu
- University of Medicine and Dentistry of New Jersey (UMDNJ)–Robert Wood Johnson Medical School, New Brunswick, NJ,UMDNJ–School of Public Health, New Brunswick, NJ
| | - Marc L Steinberg
- University of Medicine and Dentistry of New Jersey (UMDNJ)–Robert Wood Johnson Medical School, New Brunswick, NJ,UMDNJ–School of Public Health, New Brunswick, NJ
| | - Neal L Benowitz
- University of California at San Francisco, San Francisco, CA, USA
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49
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Yarnall NJ, Hughes LM, Turnbull PS, Michaud M. Evaluating the effectiveness of the US Navy and Marine Corps Tobacco Policy: an assessment of secondhand smoke exposure in US Navy submariners. Tob Control 2012; 22:e66-72. [PMID: 22871902 DOI: 10.1136/tobaccocontrol-2012-050488] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE To evaluate the effectiveness of the US Navy and Marine Corps tobacco policy in protecting submariners from secondhand smoke (SHS) by determining if non-tobacco users experienced a significant increase in urinary cotinine levels at sea when compared with in port levels. METHODS From February to August 2009, 634 volunteers recruited from nine US Navy submarines completed a survey to collect demographic data, information on tobacco use and pre-deployment exposure to SHS. Non-tobacco users (n=239) were requested to provide two urine samples (pre-deployment and while at sea) to quantify exposure to SHS using urinary cotinine as a biomarker. Matched samples were analysed using liquid chromatography-tandem mass spectrometry. RESULTS Overall, deployed cotinine levels were 2.1 times the in port levels in non-tobacco using submariners (95% CI 1.8 to 2.4, p<0.001, n=197). A significant increase in deployed urinary cotinine levels was found aboard six of nine submarines (p<0.05). A subgroup of submariners (n=91) who reported no SHS exposure within 10 days prior to in port cotinine sampling had deployed cotinine levels 2.7 times the in port levels (95% CI 2.2 to 3.3, p<0.001). Applying a 4.5:1 urine cotinine to serum cotinine correction factor, submariners' deployed geometric means are similar to recent US male population values at the 75th percentile. CONCLUSIONS This study provides evidence that non-tobacco using submariners were exposed to SHS. Exposure was seen in all submarine classes and was not limited to personnel working in proximity to the smoking area. The existing policy was inadequate to protect non-smokers from exposure to SHS and required revision. As a result of a policy review, informed by this study, smoking below decks was banned aboard all US Navy submarines effective 31 December 2010.
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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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