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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: 21] [Impact Index Per Article: 10.5] [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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2
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Shaw SA, Vokits BP, Dilger AK, Viet A, Clark CG, Abell LM, Locke GA, Duke G, Kopcho LM, Dongre A, Gao J, Krishnakumar A, Jusuf S, Khan J, Spronk SA, Basso MD, Zhao L, Cantor GH, Onorato JM, Wexler RR, Duclos F, Kick EK. Discovery and structure activity relationships of 7-benzyl triazolopyridines as stable, selective, and reversible inhibitors of myeloperoxidase. Bioorg Med Chem 2020; 28:115723. [PMID: 33007547 DOI: 10.1016/j.bmc.2020.115723] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 08/17/2020] [Accepted: 08/18/2020] [Indexed: 01/15/2023]
Abstract
Myeloperoxidase (MPO) is a heme peroxidase found in neutrophils, monocytes and macrophages that efficiently catalyzes the oxidation of endogenous chloride into hypochlorous acid for antimicrobial activity. Chronic MPO activation can lead to indiscriminate protein modification causing tissue damage, and has been associated with chronic inflammatory diseases, atherosclerosis, and acute cardiovascular events. Triazolopyrimidine 5 is a reversible MPO inhibitor; however it suffers from poor stability in acid, and is an irreversible inhibitor of the DNA repair protein methyl guanine methyl transferase (MGMT). Structure-based drug design was employed to discover benzyl triazolopyridines with improved MPO potency, as well as acid stability, no reactivity with MGMT, and selectivity against thyroid peroxidase (TPO). Structure-activity relationships, a crystal structure of the MPO-inhibitor complex, and acute in vivo pharmacodynamic data are described herein.
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Affiliation(s)
- Scott A Shaw
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States.
| | - Benjamin P Vokits
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Andrew K Dilger
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Andrew Viet
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Charles G Clark
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Lynn M Abell
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Gregory A Locke
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Gerald Duke
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Lisa M Kopcho
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Ashok Dongre
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Ji Gao
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Arathi Krishnakumar
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Sutjano Jusuf
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Javed Khan
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Steven A Spronk
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Michael D Basso
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Lei Zhao
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Glenn H Cantor
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Joelle M Onorato
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Ruth R Wexler
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Franck Duclos
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Ellen K Kick
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
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3
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Dator R, von Weymarn LB, Villalta PW, Hooyman CJ, Maertens LA, Upadhyaya P, Murphy SE, Balbo S. In Vivo Stable-Isotope Labeling and Mass-Spectrometry-Based Metabolic Profiling of a Potent Tobacco-Specific Carcinogen in Rats. Anal Chem 2018; 90:11863-11872. [PMID: 30086646 DOI: 10.1021/acs.analchem.8b01881] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), is a potent lung carcinogen that exerts its carcinogenic effects upon metabolic activation. The identification and quantitation of NNK metabolites could identify potential biomarkers of bioactivation and detoxification of this potent carcinogen and may be used to predict lung cancer susceptibility among smokers. Here, we used in vivo isotope-labeling and high-resolution-mass-spectrometry-based methods for the comprehensive profiling of all known and unknown NNK metabolites. The sample-enrichment, LC-MS, and data-analysis workflow, including a custom script for automated d0- d4- m/ z-pair-peak detection, enabled unbiased identification of numerous NNK metabolites. The structures of the metabolites were confirmed using targeted LC-MS2 with retention-time ( tR) and MS2-fragmentation comparisons to those of standards when possible. Eleven known metabolites and unchanged NNK were identified simultaneously. More importantly, our workflow revealed novel NNK metabolites, including 1,3-Diol (13), α-OH-methyl-NNAL-Gluc (14), nitro-NK- N-oxide (15), nitro-NAL- N-oxide (16), γ-OH NNAL (17), and three N-acetylcysteine (NAC) metabolites (18a-c). We measured the differences in the relative distributions of a panel of nitroso-containing NNK-specific metabolites in rats before and after phenobarbital (PB) treatment, and this served as a demonstration of a general strategy for the detection of metabolic differences in animal and cell systems. Lastly, we generated a d4-labeled NNK-metabolite mixture to be used as internal standards ( d4-rat urine) for the relative quantitation of NNK metabolites in humans, and this new strategy will be used to assess carcinogen exposure and ultimately to evaluate lung-cancer risk and susceptibility in smokers.
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Affiliation(s)
- Romel Dator
- Masonic Cancer Center , University of Minnesota , 2231 Sixth Street Southeast , Minneapolis , Minnesota 55455 , United States
| | - Linda B von Weymarn
- Masonic Cancer Center , University of Minnesota , 2231 Sixth Street Southeast , Minneapolis , Minnesota 55455 , United States
| | - Peter W Villalta
- Masonic Cancer Center , University of Minnesota , 2231 Sixth Street Southeast , Minneapolis , Minnesota 55455 , United States
| | - Cory J Hooyman
- Independent Consultant , 3732 Harriet Avenue South , Minneapolis , Minnesota 55409 , United States
| | - Laura A Maertens
- Masonic Cancer Center , University of Minnesota , 2231 Sixth Street Southeast , Minneapolis , Minnesota 55455 , United States
| | - Pramod Upadhyaya
- Masonic Cancer Center , University of Minnesota , 2231 Sixth Street Southeast , Minneapolis , Minnesota 55455 , United States
| | - Sharon E Murphy
- Masonic Cancer Center , University of Minnesota , 2231 Sixth Street Southeast , Minneapolis , Minnesota 55455 , United States
| | - Silvia Balbo
- Masonic Cancer Center , University of Minnesota , 2231 Sixth Street Southeast , Minneapolis , Minnesota 55455 , United States
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4
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Fan PW, Zhang D, Halladay JS, Driscoll JP, Khojasteh SC. Going Beyond Common Drug Metabolizing Enzymes: Case Studies of Biotransformation Involving Aldehyde Oxidase, γ-Glutamyl Transpeptidase, Cathepsin B, Flavin-Containing Monooxygenase, and ADP-Ribosyltransferase. ACTA ACUST UNITED AC 2016; 44:1253-61. [PMID: 27117704 DOI: 10.1124/dmd.116.070169] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 04/25/2016] [Indexed: 11/22/2022]
Abstract
The significant roles that cytochrome P450 (P450) and UDP-glucuronosyl transferase (UGT) enzymes play in drug discovery cannot be ignored, and these enzyme systems are commonly examined during drug optimization using liver microsomes or hepatocytes. At the same time, other drug-metabolizing enzymes have a role in the metabolism of drugs and can lead to challenges in drug optimization that could be mitigated if the contributions of these enzymes were better understood. We present examples (mostly from Genentech) of five different non-P450 and non-UGT enzymes that contribute to the metabolic clearance or bioactivation of drugs and drug candidates. Aldehyde oxidase mediates a unique amide hydrolysis of GDC-0834 (N-[3-[6-[4-[(2R)-1,4-dimethyl-3-oxopiperazin-2-yl]anilino]-4-methyl-5-oxopyrazin-2-yl]-2-methylphenyl]-4,5,6,7-tetrahydro-1-benzothiophene-2-carboxamide), leading to high clearance of the drug. Likewise, the rodent-specific ribose conjugation by ADP-ribosyltransferase leads to high clearance of an interleukin-2-inducible T-cell kinase inhibitor. Metabolic reactions by flavin-containing monooxygenases (FMO) are easily mistaken for P450-mediated metabolism such as oxidative defluorination of 4-fluoro-N-methylaniline by FMO. Gamma-glutamyl transpeptidase is involved in the initial hydrolysis of glutathione metabolites, leading to formation of proximate toxins and nephrotoxicity, as is observed with cisplatin in the clinic, or renal toxicity, as is observed with efavirenz in rodents. Finally, cathepsin B is a lysosomal enzyme that is highly expressed in human tumors and has been targeted to release potent cytotoxins, as in the case of brentuximab vedotin. These examples of non-P450- and non-UGT-mediated metabolism show that a more complete understanding of drug metabolizing enzymes allows for better insight into the fate of drugs and improved design strategies of molecules in drug discovery.
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Affiliation(s)
- Peter W Fan
- Department of Drug Metabolism and Pharmacokinetics, Genentech, Inc., South San Francisco (P.W.F., D.Z., S.C.K.); Anacor Pharmaceuticals, Inc., Palo Alto (J.S.H.); MyoKardia, Inc., South San Francisco (J.P.D.), California
| | - Donglu Zhang
- Department of Drug Metabolism and Pharmacokinetics, Genentech, Inc., South San Francisco (P.W.F., D.Z., S.C.K.); Anacor Pharmaceuticals, Inc., Palo Alto (J.S.H.); MyoKardia, Inc., South San Francisco (J.P.D.), California
| | - Jason S Halladay
- Department of Drug Metabolism and Pharmacokinetics, Genentech, Inc., South San Francisco (P.W.F., D.Z., S.C.K.); Anacor Pharmaceuticals, Inc., Palo Alto (J.S.H.); MyoKardia, Inc., South San Francisco (J.P.D.), California
| | - James P Driscoll
- Department of Drug Metabolism and Pharmacokinetics, Genentech, Inc., South San Francisco (P.W.F., D.Z., S.C.K.); Anacor Pharmaceuticals, Inc., Palo Alto (J.S.H.); MyoKardia, Inc., South San Francisco (J.P.D.), California
| | - S Cyrus Khojasteh
- Department of Drug Metabolism and Pharmacokinetics, Genentech, Inc., South San Francisco (P.W.F., D.Z., S.C.K.); Anacor Pharmaceuticals, Inc., Palo Alto (J.S.H.); MyoKardia, Inc., South San Francisco (J.P.D.), California
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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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Le H, Ford KA, Khojasteh SC, Fan PW. Elucidation of the mechanism of ribose conjugation in a pyrazole-containing compound in rodent liver. Xenobiotica 2012; 43:236-45. [PMID: 22931212 DOI: 10.3109/00498254.2012.715211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
1. Here we report on the mechanism of ribose conjugation, through NADH as a cofactor, of a pyrazole-containing compound (PT). Incubation of PT in rat liver microsomes supplemented with NADP⁺/H, NAD⁺/H, and β-nicotinamide mononucleotide (NMN) resulted in complete conjugation to the adenine dinucleotide phosphate conjugate (ADP-C), adenine dinucleotide conjugate (AD-C), and 5-phosphoribose conjugate (Rib-C1), respectively. In hepatocytes, PT predominantly formed three ribose conjugates: Rib-C1, the ribose conjugate (Rib-C2), and the carboxylic acid of Rib-C2 (Rib-C3). 2. Phosphatase inhibitors were added to hepatocyte incubations. AD-C was detected in this reaction, which suggests that one of the major pathways for the formation of the ribose conjugates is through NAD⁺/H. When AD-C was incubated with phosphatase, Rib-C1 and Rib-C2 formed. 3. To understand the in vivo relevance of this metabolic pathway, rats were dosed with PT and Rib-C2 was found in the urine. 4. Structure-activity relationship shows that replacement of the distal thiazole group in the PT to a phenyl group abolishes this conjugation. Three amino acid residues in the active site preferentially interact with the sulfur atom in the thiazole of PT. 5. In summary, PT forms direct AD-C in hepatocytes, which is further hydrolyzed by phosphatase to give ribose conjugates.
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Affiliation(s)
- Hoa Le
- Department of Drug Metabolism and Pharmacokinetics, Genentech, Inc., South San Francisco, CA, USA
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7
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Wittel UA, Momi N, Seifert G, Wiech T, Hopt UT, Batra SK. The pathobiological impact of cigarette smoke on pancreatic cancer development (review). Int J Oncol 2012; 41:5-14. [PMID: 22446714 PMCID: PMC3589138 DOI: 10.3892/ijo.2012.1414] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 01/25/2012] [Indexed: 12/13/2022] Open
Abstract
Despite extensive efforts, pancreatic cancer remains incurable. Most risk factors, such as genetic disposition, metabolic diseases or chronic pancreatitis cannot be influenced. By contrast, cigarette smoking, an important risk factor for pancreatic cancer, can be controlled. Despite the epidemiological evidence of the detrimental effects of cigarette smoking with regard to pancreatic cancer development and its unique property of being influenceable, our understanding of cigarette smoke-induced pancreatic carcinogenesis is limited. Current data on cigarette smoke-induced pancreatic carcinogenesis indicate multifactorial events that are triggered by nicotine, which is the major pharmacologically active constituent of tobacco smoke. In addition to nicotine, a vast number of carcinogens have the potential to reach the pancreatic gland, where they are metabolized, in some instances to even more toxic compounds. These metabolic events are not restricted to pancreatic ductal cells. Several studies show that acinar cells are also greatly affected. Furthermore, pancreatic cancer progenitor cells do not only derive from the ductal epithelial lineage, but also from acinar cells. This sheds new light on cigarette smoke-induced acinar cell damage. On this background, our objective is to outline a multifactorial model of tobacco smoke-induced pancreatic carcinogenesis.
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Affiliation(s)
- Uwe A Wittel
- Department of General- and Visceral Surgery, Universitätsklinik Freiburg, Freiburg, Germany.
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8
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Xia Y, Bernert JT, Jain RB, Ashley DL, Pirkle JL. Tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) in smokers in the United States: NHANES 2007-2008. Biomarkers 2011; 16:112-9. [PMID: 21114376 DOI: 10.3109/1354750x.2010.533288] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), a metabolite of the tobacco-specific nitrosamine (TSNA) 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), has been measured in urine samples from all participants aged 6 years and older from the National Health and Nutrition Examination Survey 2007-2008. Participants with a serum cotinine concentration of ≥ 10 ng/mL were identified as tobacco users, primarily cigarette smokers. Regression models were developed to calculate geometric mean NNAL concentrations adjusted for serum cotinine, urinary creatinine, cigarettes per day, and Federal Trade Commission tar values of the cigarettes smoked. Significant differences were found by gender (p=0.003) and race/ethnicity (p=0.022 for non-Hispanic white versus non-Hispanic black smokers), but not by menthol type of the cigarettes. Females and non-Hispanic white smokers had the highest adjusted means for urinary NNAL (353 and 336 pg/mL, respectively). The results from this study demonstrated significant relationships between NNAL concentrations and serum cotinine (p<0.001) and urine creatinine (p<0.001). The joint effect of linear and quadratic terms for number of cigarettes smoked per day was also statistically significant (p=0.001). In addition to addressing current NNK exposure levels, these results will form a baseline for future estimates of tobacco users' exposure to this carcinogen.
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Affiliation(s)
- Yang Xia
- Division of Laboratory Science, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, USA.
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9
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Zhang S, Wang M, Villalta PW, Lindgren BR, Upadhyaya P, Lao Y, Hecht SS. Analysis of pyridyloxobutyl and pyridylhydroxybutyl DNA adducts in extrahepatic tissues of F344 rats treated chronically with 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and enantiomers of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol. Chem Res Toxicol 2009; 22:926-36. [PMID: 19358518 PMCID: PMC2701567 DOI: 10.1021/tx900015d] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and its metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) are potent pulmonary carcinogens in rats. NNK and NNAL require metabolic activation to express their carcinogenicity. Cytochrome P450-catalyzed alpha-hydroxylation at the methyl position of NNK or NNAL generates reactive intermediates, which alkylate DNA to form pyridyloxobutyl (POB)-DNA adducts or pyridylhydroxybutyl (PHB)-DNA adducts. NNK is metabolized to NNAL in a reversible and stereoselective manner, and the tissue-specific retention of (S)-NNAL is believed to be important to the carcinogenicity of NNK. In the present study, we investigated the formation of POB- and PHB-DNA adducts in extrahepatic tissues of F344 rats treated chronically with NNK and (R)- and (S)-NNAL (10 ppm in the drinking water, 1-20 weeks). POB- and PHB-DNA adducts were quantified in nasal olfactory mucosa, nasal respiratory mucosa, oral mucosa, and pancreas of treated rats. Adduct formation in the nasal respiratory mucosa exceeded that in the other tissues. O(2)-[4-(3-Pyridyl)-4-oxobut-1-yl]thymidine (O(2)-POB-dThd) or O(2)-[4-(3-pyridyl)-4-hydroxybut-1-yl]thymidine (O(2)-PHB-dThd) was the major adduct, followed by 7-[4-(3-pyridyl)-4-oxobut-1-yl]guanine (7-POB-Gua) or 7-[4-(3-pyridyl)-4-hydroxybut-1-yl]guanine (7-PHB-Gua). There was a remarkable similarity in adduct formation between the NNK and the (S)-NNAL groups, both of which were distinctively different from that in the (R)-NNAL group. For example, in the nasal olfactory mucosa, POB-DNA adduct levels in the NNK and (S)-NNAL groups were not significantly different from each other, while (R)-NNAL treatment generated 6-33 times lower amounts of POB-DNA adducts than did NNK treatment. In contrast, (R)-NNAL treatment produced significantly higher levels of PHB-DNA adducts than did NNK or (S)-NNAL treatment. Similar trends were observed in the nasal respiratory mucosa, oral mucosa, and pancreas. These results suggest extensive retention of (S)-NNAL in various tissues of NNK-treated rats and support a mechanism in which the preferential metabolism of NNK to (S)-NNAL, followed by sequestration of (S)-NNAL in the target tissues and reoxidation to NNK, is important to NNK tumorigenesis.
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Affiliation(s)
- Siyi Zhang
- Department of Medicinal Chemistry and Masonic Cancer Center, University of Minnesota Minneapolis, MN
| | - Mingyao Wang
- Department of Medicinal Chemistry and Masonic Cancer Center, University of Minnesota Minneapolis, MN
| | - Peter W. Villalta
- Department of Medicinal Chemistry and Masonic Cancer Center, University of Minnesota Minneapolis, MN
| | - Bruce R. Lindgren
- Department of Medicinal Chemistry and Masonic Cancer Center, University of Minnesota Minneapolis, MN
| | - Pramod Upadhyaya
- Department of Medicinal Chemistry and Masonic Cancer Center, University of Minnesota Minneapolis, MN
| | | | - Stephen S. Hecht
- Department of Medicinal Chemistry and Masonic Cancer Center, University of Minnesota Minneapolis, MN
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Ma S, Subramanian R, Xu Y, Schrag M, Shou M. Structural characterization of novel adenine dinucleotide phosphate conjugates of imatinib in incubations with rat and human liver microsomes. Drug Metab Dispos 2008; 36:2414-8. [PMID: 18799804 DOI: 10.1124/dmd.108.023085] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Imatinib, a potent and selective protein tyrosine kinase inhibitor, has been approved for the treatment of chronic myelogenous leukemia and metastatic and unresectable malignant gastrointestinal stromal tumors. In vitro metabolism of imatinib was investigated in rat and human liver microsomes. Besides several oxidative metabolites and an N-desmethyl metabolite, as previous reported, a novel metabolite with a mass addition of 621 atomic mass units to the parent was detected as the major metabolite in the incubations with rat liver microsomes, using NADPH as a cofactor. The analysis of MS(2) and MS(n) data revealed that this metabolite corresponded to adenine dinucleotide phosphate (ADP+) conjugate of imatinib. The ADP+ adduct was scaled up from rat liver microsomal incubations and isolated for NMR analysis. NMR data confirmed and conclusively showed the conjugation had occurred between the pyridine nitrogen of imatinib to the ribose ring of ADP+ moiety. The formation of this adduct was enzymatic and required NADP+ as a reactant. In addition, ADP+ adducts of imatinib N-oxide and desmethyl imatinib were also detected as minor metabolites in the incubations with rat liver microsomes. In contrast, only trace levels of ADP+ adducts of imatinib and desmethyl imatinib were detected in the incubations with human liver microsomes. Imatinib-ADP+ adducts have been observed only in in vitro studies to date. The physiological role of these adducts is not clear, nor is their in vivo relevance.
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Affiliation(s)
- Shuguang Ma
- Drug Metabolism and Pharmacokinetics, Schering-Plough Research Institute, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA.
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11
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Brown B, Avalos J, Lee C, Doolittle D. The effect of tobacco smoke, nicotine, and cotinine on the mutagenicity of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL). Mutat Res 2001; 494:21-9. [PMID: 11423342 DOI: 10.1016/s1383-5718(01)00174-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) is a rodent carcinogen that is metabolically derived from carbonyl reduction of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). NNAL can be pyridine N-oxidized to form NNAL-N-oxide, or conjugated to form NNAL-glucuronide - non-genotoxic metabolites that can be excreted in urine. Alternatively, NNAL can be alpha-hydroxylated at the methyl and methylene carbons adjacent to the nitroso group to generate electrophiles that can react with biological macromolecules, such as DNA and proteins. Our laboratory has previously demonstrated that the mutagenicity of NNK was significantly inhibited by the aqueous extract of tobacco smoke, as well as pyridine alkaloids in cigarette smoke, such as nicotine, cotinine and nornicotine. Given the structural similarity between NNK and NNAL, and the metabolic activation of both by cytochromes P450, we hypothesized that there may be a similar inhibition of NNAL metabolism, and consequently, inhibition of the mutagenic activity of NNAL by tobacco smoke and its pyridine alkaloid constituents. In the present study, we evaluated the ability of two pyridine alkaloids (nicotine and cotinine) and aqueous cigarette smoke condensate extract (ACTE) to inhibit the mutagenicity of NNAL in Salmonella typhimurium strain TA1535 in the presence of a metabolic activation system (S9). Both pyridine alkaloids tested, as well as ACTE, inhibited the mutagenicity of NNAL in a concentration-dependent manner. The observed reductions in mutagenicity were not the result of cell killing due to cytotoxicity. These results demonstrate that tobacco smoke contains pyridine alkaloids, as well as other unidentified constituents that inhibit the mutagenicity of NNAL, a major metabolite of NNK.
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Affiliation(s)
- B Brown
- Environmental and Molecular Toxicology, Research and Development, P.O. Box 1236, R.J. Reynolds Tobacco Company, Winston-Salem, NC 27102, USA.
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Upadhyaya P, Carmella SG, Guengerich F, Hecht SS. Formation and metabolism of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol enantiomers in vitro in mouse, rat and human tissues. Carcinogenesis 2000. [DOI: 10.1093/carcin/21.6.1233] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Upadhyaya P, Carmella SG, Guengerich F, Hecht SS. Formation and metabolism of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol enantiomers in vitro in mouse, rat and human tissues. Carcinogenesis 2000. [DOI: 10.1093/carcin/21.5.233] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Nunes MG, Desai D, Koehl W, Spratt TE, Guengerich FP, Amin S. Inhibition of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) metabolism in human hepatic microsomes by ipomeanol analogs--an exploratory study. Cancer Lett 1998; 129:131-8. [PMID: 9719453 DOI: 10.1016/s0304-3835(98)00049-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The tobacco-specific 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a potent lung carcinogen in mice, rats and Syrian golden hamsters and a suspected human lung carcinogen. We have reported earlier that structural analogs of the naturally occurring pulmonary toxin 4-ipomeanol (IPO) were non toxic up to 50 micromol/mouse. Because these analogs are in part structurally similar to NNK, they are expected to compete for the same enzymes and/or reactive sites within DNA. Both NNK and IPO are primarily metabolized by cytochrome P450 enzymes in the Clara cells of the lung but also in the liver. We describe here the optimal conditions for the study of NNK metabolism in human liver microsomes and our investigation of four non-toxic IPO analogs as potential inhibitors of NNK activation. The IPO analogs studied were 4-hydroxy-1-phenyl-1-octanone (4-HPO), 1,4-diphenyl-4-hydroxy-1-butanone (DPHB), 4-hydroxy-1-phenylpentane (HPPentane) and amyl benzene (AB). When added to microsomal incubations of human liver cells at a concentration of 100 microM, all of these compounds were strong inhibitors of NNK activation, decreasing the total alpha-hydroxylation of NNK, which is the main pathway of activation, by 60-70% and preventing N-oxidation by 78-86%.
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Affiliation(s)
- M G Nunes
- Naylor Dana Institute for Disease Prevention, American Health Foundation, Valhalla, NY 10595, USA
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el-Bayoumy K, Prokopczyk B, Peterson LA, Desai D, Amin S, Reddy BS, Hoffmann D, Wynder E. Effects of dietary fat content on the metabolism of NNK and on DNA methylation induced by NNK. Nutr Cancer 1996; 26:1-10. [PMID: 8844716 DOI: 10.1080/01635589609514457] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The available data support the concept that high-fat diets increase cytochrome P-450 activities in the liver, leading to increased rates of carcinogen metabolism and, in some instances, DNA adduct formation. Therefore we investigated whether a high-fat diet can also influence DNA methylation by the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in the lungs of rats. Male F344 rats were fed a regular AIN-76A low-fat (5% corn oil) or AIN-76A high-fat (23.5% corn oil) diet. After three weeks on this dietary regimen, the animals were injected subcutaneously once daily for four days with NNK at 0.39 mmol/kg body wt. Groups of rats were sacrificed 4 and 24 hours after the last NNK administration; livers and lungs were excised for DNA isolation. We found that the high-fat diet significantly enhanced the formation of O6-methylguanine (O6-mGua) in the rat lung four hours (p < 0.01) after the last carcinogen administration. This may, in part, account for our previous finding in regard to the enhancing effect of the high-fat diet on NNK-induced lung carcinogenesis. There was no effect on O6-mGua or 7-mGua in the rat liver at either time point. To further elucidate the enhancing effect of the high-fat diet on DNA methylation by NNK in the lung, we determined its effect on the in vitro and in vivo metabolism of NNK. The in vitro data indicated that dietary fat has no measurable effect on liver and lung microsomal mixed-function oxidase in catalyzing the metabolic activation of NNK. The results of the metabolism study of NNK in vivo appear to be consistent with the in vitro finding, in that fat had no effect on the excretion pattern of NNK or on the distribution pattern of its urinary metabolites. It is apparent that the enhancing effect of the high-fat diet on O6-mGua in the lung of rats that was measured four hours after NNK injection requires future investigations.
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Affiliation(s)
- K el-Bayoumy
- Div. of Cancer Etiology and Prevention, American Health Foundation, Valhalla, NY 10595, USA
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Hecht SS. Recent studies on mechanisms of bioactivation and detoxification of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a tobacco-specific lung carcinogen. Crit Rev Toxicol 1996; 26:163-81. [PMID: 8688159 DOI: 10.3109/10408449609017929] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
This article reviews recent advances in the biochemistry and molecular biology of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a tobacco-specific pulmonary carcinogen believed to be involved in the induction of lung cancer in smokers. Several aspects of NNK bioactivation are addressed, including identification of its metabolites in laboratory animals and humans, cytochrome P450 enzyme involvement in its metabolic activation, DNA and protein adduct formation, biological significance of the major DNA adducts formed, and mutations in oncogenes from tumors induced by NNK. Collectively, the presently available data provide a reasonably clear picture of NNK bioactivation in rodents, although there are still important gaps in our mechanistic understanding of NNK-induced tumorigenesis. The studies in rodents and primates have facilitated development of methods to assess NNK bioactivation in humans, which will be applicable to studies of lung cancer susceptibility and prevention.
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Affiliation(s)
- S S Hecht
- American Health Foundation, Valhalla, NY 10595, USA
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