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Abstract
Recent developments in biomarkers relating to the interrelationship of diet, disease and health were surveyed. Most emphasis was placed on biomarkers of deleterious effects, since these are of greatest relevance to the subject of this review. The area of greatest activity was found to be that relating to biomarkers of mutagenic, genotoxic and carcinogenic effects. This is also one of the major areas of concern in considerations of the beneficial and deleterious effects of dietary components, and also the area in which regulatory testing requires studies of the longest duration. A degree of progress has also been made in the identification and development of biomarkers relating to certain classes of target organ toxicity. Biomarkers for other types of toxicity, such as immunotoxicity, neurotoxicity, reproductive toxicity and developmental toxicity, are less developed, and further investigation in these areas is required before a comprehensive biomarker strategy can be established. A criticism that recurs constantly in the biomarker literature is the lack of standardisation in the methods used, and the lack of reference standards for the purposes of validation and quality control. It is encouraging to note the growing acknowledgement of the need for validation of biomarkers and biomarker assays. Some validation studies have already been initiated. This review puts forward proposals for criteria to be used in biomarker validation. More discussion on this subject is required. It is concluded that the use of biomarkers can, in some cases, facilitate the implementation of the Three Rs with respect to the testing of food chemicals and studies on the effects of diet on health. The greatest potential is seen to be in the refinement of animal testing, in which biomarkers could serve as early and sensitive endpoints, in order to reduce the duration of the studies and also reduce the number of animals required. Biomarkers could also contribute to establishing a mechanistic basis for in vitro test systems and to facilitating their validation and acceptance. Finally, the increased information that could result from the incorporation of biomarker determinations into population studies could reduce the need for supplementary animal studies. This review makes a number of recommendations concerning the prioritisation of future activities on dietary biomarkers in relation to the Three Rs. It is emphasised, however, that further discussions will be required among toxicologists, epidemiologists and others researching the relationship between diet and health.
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Affiliation(s)
- Krys Bottrill
- FRAME, Russell & Burch House, 96–98 North Sherwood Street, Nottingham NG1 4EE, UK
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Yun BH, Guo J, Bellamri M, Turesky RJ. DNA adducts: Formation, biological effects, and new biospecimens for mass spectrometric measurements in humans. MASS SPECTROMETRY REVIEWS 2020; 39:55-82. [PMID: 29889312 PMCID: PMC6289887 DOI: 10.1002/mas.21570] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 04/25/2018] [Indexed: 05/18/2023]
Abstract
Hazardous chemicals in the environment and diet or their electrophilic metabolites can form adducts with genomic DNA, which can lead to mutations and the initiation of cancer. In addition, reactive intermediates can be generated in the body through oxidative stress and damage the genome. The identification and measurement of DNA adducts are required for understanding exposure and the causal role of a genotoxic chemical in cancer risk. Over the past three decades, 32 P-postlabeling, immunoassays, gas chromatography/mass spectrometry, and liquid chromatography/mass spectrometry (LC/MS) methods have been established to assess exposures to chemicals through measurements of DNA adducts. It is now possible to measure some DNA adducts in human biopsy samples, by LC/MS, with as little as several milligrams of tissue. In this review article, we highlight the formation and biological effects of DNA adducts, and highlight our advances in human biomonitoring by mass spectrometric analysis of formalin-fixed paraffin-embedded tissues, untapped biospecimens for carcinogen DNA adduct biomarker research.
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Affiliation(s)
- Byeong Hwa Yun
- Masonic Cancer Center and Department of Medicinal Chemistry, University of Minnesota, 2231 6 St. SE, Minneapolis, Minnesota, 55455, United States
| | - Jingshu Guo
- Masonic Cancer Center and Department of Medicinal Chemistry, University of Minnesota, 2231 6 St. SE, Minneapolis, Minnesota, 55455, United States
| | - Medjda Bellamri
- Masonic Cancer Center and Department of Medicinal Chemistry, University of Minnesota, 2231 6 St. SE, Minneapolis, Minnesota, 55455, United States
| | - Robert J. Turesky
- Masonic Cancer Center and Department of Medicinal Chemistry, University of Minnesota, 2231 6 St. SE, Minneapolis, Minnesota, 55455, United States
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Affiliation(s)
- Julia Kastner
- University of Maryland School of Medicine, Baltimore, MD
| | - Rydhwana Hossain
- University of Maryland School of Medicine, Cardiothoracic Imaging, Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland Medical Center, Baltimore, MD
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Bist I, Bhakta S, Jiang D, Keyes TE, Martin A, Forster RJ, Rusling JF. Evaluating Metabolite-Related DNA Oxidation and Adduct Damage from Aryl Amines Using a Microfluidic ECL Array. Anal Chem 2017; 89:12441-12449. [PMID: 29083162 PMCID: PMC5777145 DOI: 10.1021/acs.analchem.7b03528] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Damage to DNA from the metabolites of drugs and pollutants constitutes a major human toxicity pathway known as genotoxicity. Metabolites can react with metal ions and NADPH to oxidize DNA or participate in SN2 reactions to form covalently linked adducts with DNA bases. Guanines are the main DNA oxidation sites, and 8-oxo-7,8-dihydro-2-deoxyguanosine (8-oxodG) is the initial product. Here we describe a novel electrochemiluminescent (ECL) microwell array that produces metabolites from test compounds and measures relative rates of DNA oxidation and DNA adduct damage. In this new array, films of DNA, metabolic enzymes, and an ECL metallopolymer or complex assembled in microwells on a pyrolytic graphite wafer are housed in dual microfluidic chambers. As reactant solution passes over the wells, metabolites form and can react with DNA in the films to form DNA adducts. These adducts are detected by ECL from a RuPVP polymer that uses DNA as a coreactant. Aryl amines also combine with Cu2+ and NADPH to form reactive oxygen species (ROS) that oxidize DNA. The resulting 8-oxodG was detected selectively by ECL-generating bis(2,2'-bipyridine)-(4-(1,10-phenanthrolin-6-yl)-benzoic acid)Os(II). DNA/enzyme films on magnetic beads were oxidized similarly, and 8-oxodG determined by LC/MS/MS enabled array standardization. The array limit of detection for oxidation was 720 8-oxodG per 106 nucleobases. For a series of aryl amines, metabolite-generated DNA oxidation and adduct formation turnover rates from the array correlated very well with rodent 1/TD50 and Comet assay results.
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Affiliation(s)
- Itti Bist
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Snehasis Bhakta
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Di Jiang
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Tia E. Keyes
- School of Chemical Sciences, Dublin City University, Dublin 9, Ireland
| | - Aaron Martin
- School of Chemical Sciences, Dublin City University, Dublin 9, Ireland
| | - Robert J. Forster
- School of Chemical Sciences, Dublin City University, Dublin 9, Ireland
| | - James F. Rusling
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
- Institute of Materials Science, University of Connecticut, 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, Galway, University Road, Galway H91 TK33, Ireland
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Ceppi M, Munnia A, Cellai F, Bruzzone M, Peluso MEM. Linking the generation of DNA adducts to lung cancer. Toxicology 2017; 390:160-166. [PMID: 28928033 DOI: 10.1016/j.tox.2017.09.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 09/11/2017] [Accepted: 09/15/2017] [Indexed: 11/29/2022]
Abstract
Worldwide, lung cancer is the leading cause of cancer death. DNA adducts are considered a reliable biomarker that reflects carcinogen exposure to tobacco smoke, but the central question is what is the relationship of DNA adducts and cancer? Therefore, we investigated this relationship by a meta-analysis of twenty-two studies with bronchial adducts for a total of 1091 subjects, 887 lung cancer cases and 204 apparently healthy individuals with no evidence of lung cancer. Our study shows that these adducts are significantly associated to increase lung cancer risk. The value of Mean Ratiolung-cancer (MR) of bronchial adducts resulting from the random effects model was 2.64, 95% C.I. 2.00-3.50, in overall lung cancer cases as compared to controls. The significant difference, with lung cancer patients having significant higher levels of bronchial adducts than controls, persisted after stratification for smoking habits. The MRlung-cancer value between lung cancer patients and controls for smokers was 2.03, 95% C.I. 1.42-2.91, for ex-smokers 3.27, 95% C.I. 1.49-7.18, and for non-smokers was 3.81, 95% C.I. 1.85-7.85. Next, we found that the generation of bronchial adducts is significantly related to inhalation exposure to tobacco smoke carcinogens confirming its association with volatile carcinogens. The MRsmoking estimate of bronchial adducts resulting from meta-regression was 2.28, 95% Confidence Interval (C.I.) 1.10-4.73, in overall smokers in respect to non-smokers. The present work provides strengthening of the hypothesis that bronchial adducts are not simply relate to exposure, but are a cause of chemical-induced lung cancer.
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Affiliation(s)
- Marcello Ceppi
- Clinical Epidemiology Branch, IRCCS - Ospedale Policlinico San Martino, Largo R. Benzi 10, 16132 Genoa, Italy
| | - Armelle Munnia
- Cancer Risk Factor Branch, Regional Cancer Prevention Laboratory, ISPOCancer Prevention and Research Institute, 50139 - Florence, Italy
| | - Filippo Cellai
- Cancer Risk Factor Branch, Regional Cancer Prevention Laboratory, ISPOCancer Prevention and Research Institute, 50139 - Florence, Italy
| | - Marco Bruzzone
- Clinical Epidemiology Branch, IRCCS - Ospedale Policlinico San Martino, Largo R. Benzi 10, 16132 Genoa, Italy
| | - Marco E M Peluso
- Cancer Risk Factor Branch, Regional Cancer Prevention Laboratory, ISPOCancer Prevention and Research Institute, 50139 - Florence, Italy.
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Plant flavonoids in cancer chemoprevention: role in genome stability. J Nutr Biochem 2017; 45:1-14. [DOI: 10.1016/j.jnutbio.2016.11.007] [Citation(s) in RCA: 215] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Revised: 08/27/2016] [Accepted: 11/14/2016] [Indexed: 12/13/2022]
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Munnia A, Giese RW, Polvani S, Galli A, Cellai F, Peluso MEM. Bulky DNA Adducts, Tobacco Smoking, Genetic Susceptibility, and Lung Cancer Risk. Adv Clin Chem 2017. [PMID: 28629590 DOI: 10.1016/bs.acc.2017.01.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The generation of bulky DNA adducts consists of conjugates formed between large reactive electrophiles and DNA-binding sites. The term "bulky DNA adducts" comes from early experiments that employed a 32P-DNA postlabeling approach. This technique has long been used to elucidate the association between adducts and carcinogen exposure in tobacco smoke studies and assess the predictive value of adducts in cancer risk. Molecular data showed increased DNA adducts in respiratory tracts of smokers vs nonsmokers. Experimental studies and meta-analysis demonstrated that the relationship between adducts and carcinogens was linear at low doses, but reached steady state at high exposure, possibly due to metabolic and DNA repair pathway saturation and increased apoptosis. Polymorphisms of metabolic and DNA repair genes can increase the effects of environmental factors and confer greater likelihood of adduct formation. Nevertheless, the central question remains as to whether bulky adducts cause human cancer. If so, lowering them would reduce cancer incidence. Pooled and meta-analysis has shown that smokers with increased adducts have increased risk of lung cancer. Adduct excess in smokers, especially in prospective longitudinal studies, supports their use as biomarkers predictive of lung cancer.
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Affiliation(s)
- Armelle Munnia
- Cancer Risk Factor Branch, Regional Cancer Prevention Laboratory, ISPO-Cancer Prevention and Research Institute, Florence, Italy
| | - Roger W Giese
- Bouve College of Health Sciences, Barnett Institute, Northeastern University, Boston, MA, United States
| | - Simone Polvani
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Andrea Galli
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Filippo Cellai
- Cancer Risk Factor Branch, Regional Cancer Prevention Laboratory, ISPO-Cancer Prevention and Research Institute, Florence, Italy
| | - Marco E M Peluso
- Cancer Risk Factor Branch, Regional Cancer Prevention Laboratory, ISPO-Cancer Prevention and Research Institute, Florence, Italy.
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Tomioka K, Saeki K, Obayashi K, Kurumatani N. Risk of Lung Cancer in Workers Exposed to Benzidine and/or Beta-Naphthylamine: A Systematic Review and Meta-Analysis. J Epidemiol 2016; 26:447-58. [PMID: 26947956 PMCID: PMC5008964 DOI: 10.2188/jea.je20150233] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 10/25/2015] [Indexed: 11/18/2022] Open
Abstract
Benzidine (BZ) and beta-naphthylamine (BNA) have been classified as definite human carcinogens for bladder cancer by the International Agency for Research on Cancer. However, the epidemiological evidence for an association between exposure to BZ and/or BNA and lung cancer has been inconclusive. We conducted a systematic review and meta-analysis to determine the risk for lung cancer among workers exposed to BZ/BNA. A systematic literature search was conducted to identify studies that had reported occupational BZ/BNA exposure and the outcome of interest (lung cancer death and/or incidence). Meta-analyses were performed using random effects models to combine standardized mortality ratios (SMRs) or standardized incidence ratios (SIRs). We identified 23 retrospective cohort studies including 1745 cases of lung cancer; only one study reported smoking-adjusted lung cancer risk. A significantly increased lung cancer risk (pooled SMR/SIR 1.28; 95% CI, 1.14-1.43) was observed by combining all studies, with significant heterogeneity among studies (I(2) = 64.1%, P < 0.001). Effect estimates were higher for studies with direct BZ/BNA exposure (ie, dyestuff and manufacturing industries) (pooled SMR/SIR 1.58; 95% CI, 1.31-1.89), and studies that identified BZ/BNA-associated bladder cancer with SMR/SIR ≥4.7 (pooled SMR/SIR 1.68; 95% CI, 1.35-2.09). Effect estimates were similar for studies with and without concomitant occupational exposure to chromium, asbestos, arsenic, or bis(chloromethyl) ether. The cumulative meta-analysis showed that the evidence of association between occupational BZ/BNA exposure and lung cancer has been stable since 1995. Although the results of this meta-analysis have the potential for confounding by smoking and heterogeneity, our findings suggest that a finding of lung cancer following occupational BZ/BNA exposure should be considered to be a potential occupational disease.
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Monien BH, Schumacher F, Herrmann K, Glatt H, Turesky RJ, Chesné C. Simultaneous detection of multiple DNA adducts in human lung samples by isotope-dilution UPLC-MS/MS. Anal Chem 2014; 87:641-8. [PMID: 25423194 PMCID: PMC4287830 DOI: 10.1021/ac503803m] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Recent studies have demonstrated
that various DNA adducts can be
detected in human tissues and fluids using liquid chromatography connected
to tandem mass spectrometry (LC-MS/MS). However, the utility of a
single DNA adduct as a biomarker in risk assessment is debatable because
humans are exposed to many genotoxicants. We established a method
to measure DNA adducts derived from 16 ubiquitous genotoxicants and
developed an analytical technique for their simultaneous quantification
by ultra performance liquid chromatography (UPLC)-MS/MS. Methods for
the enrichment of the analytes from DNA hydrolysates and chromatographic
separation preceding mass spectrometric analysis were optimized, and
the resultant technique was used for the simultaneous analysis of
the 16 DNA adducts in human lung biopsy specimens. Eleven adducts
(formed by benzo[a]pyrene, 1-methylpyrene, 4-aminobiphenyl,
2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine,
1-methoxy-3-indolylmethylglucosinolate, 5-hydroxymethylfurfural, and
malondialdehyde) were not detected in any tissue sample (limits of
detection: 0.02–7.1 adducts/108 nucleosides). 3,N4-etheno-2′-deoxycytidine and 1,N6-etheno-2′-deoxyadenosine, formed from
2,3-epoxyaldehydes of endogenous lipid peroxidation products, were
present in all subjects (16.9–115.3 and 27.2–179/108 nucleosides, respectively). The same was true for N2-(trans-methylisoeugenol-3′-yl)-2′-deoxyguanosine,
the major adduct of methyleugenol (1.7–23.7/108 nucleosides).
A minor adduct of methyleugenol and two adducts of furfuryl alcohol
were detected in several pulmonary specimens. Taken together, we developed
a targeted approach for the simultaneous mass spectrometric analyses
of 16 DNA adducts, which can be easily extended by adducts formed
from other mutagens. The method allowed one to detect adducts of furfuryl
alcohol and methyleugenol in samples of human lung.
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Affiliation(s)
- Bernhard H Monien
- Research Group Genotoxic Food Contaminants, German Institute of Human Nutrition (DIfE) , 14558 Nuthetal, Germany
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Kovacic P, Somanathan R. Nitroaromatic compounds: Environmental toxicity, carcinogenicity, mutagenicity, therapy and mechanism. J Appl Toxicol 2014; 34:810-24. [PMID: 24532466 DOI: 10.1002/jat.2980] [Citation(s) in RCA: 236] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 11/25/2013] [Accepted: 11/26/2013] [Indexed: 12/21/2022]
Abstract
Vehicle pollution is an increasing problem in the industrial world. Aromatic nitro compounds comprise a significant portion of the threat. In this review, the class includes nitro derivatives of benzene, biphenyls, naphthalenes, benzanthrone and polycyclic aromatic hydrocarbons, plus nitroheteroaromatic compounds. The numerous toxic manifestations are discussed. An appreciable number of drugs incorporate the nitroaromatic structure. The mechanistic aspects of both toxicity and therapy are addressed in the context of a unifying mechanism involving electron transfer, reactive oxygen species, oxidative stress and antioxidants.
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Affiliation(s)
- Peter Kovacic
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, USA
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Turesky RJ, Le Marchand L. Metabolism and biomarkers of heterocyclic aromatic amines in molecular epidemiology studies: lessons learned from aromatic amines. Chem Res Toxicol 2011; 24:1169-214. [PMID: 21688801 PMCID: PMC3156293 DOI: 10.1021/tx200135s] [Citation(s) in RCA: 217] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Aromatic amines and heterocyclic aromatic amines (HAAs) are structurally related classes of carcinogens that are formed during the combustion of tobacco or during the high-temperature cooking of meats. Both classes of procarcinogens undergo metabolic activation by N-hydroxylation of the exocyclic amine group to produce a common proposed intermediate, the arylnitrenium ion, which is the critical metabolite implicated in toxicity and DNA damage. However, the biochemistry and chemical properties of these compounds are distinct, and different biomarkers of aromatic amines and HAAs have been developed for human biomonitoring studies. Hemoglobin adducts have been extensively used as biomarkers to monitor occupational and environmental exposures to a number of aromatic amines; however, HAAs do not form hemoglobin adducts at appreciable levels, and other biomarkers have been sought. A number of epidemiologic studies that have investigated dietary consumption of well-done meat in relation to various tumor sites reported a positive association between cancer risk and well-done meat consumption, although some studies have shown no associations between well-done meat and cancer risk. A major limiting factor in most epidemiological studies is the uncertainty in quantitative estimates of chronic exposure to HAAs, and thus, the association of HAAs formed in cooked meat and cancer risk has been difficult to establish. There is a critical need to establish long-term biomarkers of HAAs that can be implemented in molecular epidemioIogy studies. In this review, we highlight and contrast the biochemistry of several prototypical carcinogenic aromatic amines and HAAs to which humans are chronically exposed. The biochemical properties and the impact of polymorphisms of the major xenobiotic-metabolizing enzymes on the biological effects of these chemicals are examined. Lastly, the analytical approaches that have been successfully employed to biomonitor aromatic amines and HAAs, and emerging biomarkers of HAAs that may be implemented in molecular epidemiology studies are discussed.
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Affiliation(s)
- Robert J Turesky
- Division of Environmental Health Sciences, Wadsworth Center , Albany, New York 12201, United States.
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Anna L, Kovács K, Gyorffy E, Schoket B, Nair J. Smoking-related O4-ethylthymidine formation in human lung tissue and comparisons with bulky DNA adducts. Mutagenesis 2011; 26:523-7. [PMID: 21454326 DOI: 10.1093/mutage/ger011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Tobacco smoke contains many alkylating agents that can react with DNA to produce O(4)-ethylthymidine (O(4)-etT) and several other types of promutagenic base modifications. Our aims were (i) to confirm results of a pilot study (Godschalk, R., Nair, J., Schooten, F. J., Risch, A., Drings, P., Kayser, K., Dienemann, H. and Bartsch, H. (2002) Comparison of multiple DNA adduct types in tumor adjacent human lung tissue: effect of cigarette smoking. Carcinogenesis, 23, 2081-2086) on the formation of O(4)-etT in smokers' lung; (ii) to explore associations between levels of O(4)-etT and smoking status and (iii) to investigate whether a correlation exists between levels of O(4)-etT and bulky (polycyclic aromatic hydrocarbons-derived) DNA adducts. Archived DNA samples originated from histologically normal peripheral lung tissues of 64 Hungarian lung cancer patients, who underwent lung resection. O(4)-etT was determined by an immunoenriched (32)P-postlabelling-high-performance liquid chromatography method. Levels of bulky DNA adducts were determined by the nuclease P1 adduct-enriched (32)P-postlabelling. O(4)-etT levels ranged from 0.01 to 3.91 adducts/10(8) thymidines. In the combined group of subjects who smoked until surgery or gave up smoking at most 1 year before it, the mean level of O(4)-etT was 1.7-fold (P = 0.015) and of bulky DNA adducts 2.2-fold (P < 0.0001) higher than in long-term ex-smokers (LES) and never-smokers (NS) combined. We found no significant correlation between the individual levels of the two DNA adduct types. No dose-response was detected between O(4)-etT formation and smoking dose. In one-third of LES, O(4)-etT levels were above the 2.0-fold mean level of adducts found in NS, indicating its high persistence. Our results confirm the smoking-related formation of O(4)-etT in human lung DNA that should be explored as biomarker. Its long persistence in target tissue implicates a role of this potentially miscoding lesion in tobacco smoking-associated cancers.
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Affiliation(s)
- Lívia Anna
- Department of Molecular Environmental Epidemiology, National Institute of Environmental Health, Gyáli út 2-6, H-1097 Budapest, Hungary.
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Böhm F, Schmid D, Denzinger S, Wieland WF, Richter E. DNA adducts of ortho-toluidine in human bladder. Biomarkers 2010; 16:120-8. [PMID: 21117897 DOI: 10.3109/1354750x.2010.534556] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND 4-Aminobiphenyl (4-ABP) and o-toluidine are known human bladder carcinogens, but only 4-ABP-releasing DNA adducts are known. METHODS Determination of 4-ABP and o-toluidine-releasing DNA adducts in epithelial and submucosal bladder tissues of sudden death victims (SDV: n=46), and bladder tumours (n=12) by gas chromatography/mass spectrometry. RESULTS Above background, 4 and 11 of 12 tumour samples contained adducts of 4-ABP (0.057 ± 0.125 fmol/µg DNA) and o-toluidine (8.72 ± 4.49 fmol/µg DNA), respectively. Lower adduct levels were present in both epithelial and submucosal bladder tissues of SDV (4-ABP: 0.011 ± 0.022 and 0.019 ± 0.047 fmol/µg DNA; o-toluidine: 0.24 ± 0.63 and 0.27 ± 0.70 fmol/µg DNA). CONCLUSION Detection of o-toluidine-releasing DNA adducts support the carcinogenicity of o-toluidine in the human bladder.
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Affiliation(s)
- Francine Böhm
- Walther Straub Institute, Department of Toxicology, Ludwig-Maximilians-University, Nussbaumstrasse 26, D-80336 Munich, Germany
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The GSTP1 Ile105 Val polymorphism modifies the metabolism of toluene di-isocyanate. Pharmacogenet Genomics 2010; 20:104-11. [PMID: 20032816 DOI: 10.1097/fpc.0b013e328334fb84] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Toluene di-isocyanate (TDI) is widely used in the production of polyurethane foams and paints. As TDI causes respiratory disease in only a fraction of exposed workers, genetic factors may play a key role in disease susceptibility. Polymorphisms in TDI metabolising genes may affect elimination kinetics, resulting in differences in body retention, and in its turn differences in adverse effects. OBJECTIVES To analyze how genotype modifies the associations between (i) TDI in air (2,4-TDI and 2,6-TDI) and its metabolites toluene diamine (TDA; 2,4-TDA and 2,6-TDA) in hydrolyzed urine; and (ii) 2,4-TDA and 2,6-TDA in hydrolyzed plasma and 2,4-TDA and 2,6-TDA in urine. METHODS Workers exposed to TDI were analyzed for 2,4-TDI and 2,6-TDI in air (N=70), 2,4-TDA and 2,6-TDA in hydrolyzed urine (N=124) and in plasma (N=128), and genotype: CYP1A1*2A, CYP1A1*2B, GSTA1-52, GSTM1O, GSTM3B, GSTP1 I105V, GSTP1 A114V, GSTT1O, MPO-463, NAT1*3, *4, *10, *11, *14, *15, NAT2*5, *6, *7, and SULT1A1 R213H. RESULTS GSTP1 105 strongly modified the relationship between 2,4-TDA in plasma and in urine: ValVal carriers had about twice as steep regression slope than IleIle carriers. A similar pattern was found for 2,6-TDA. CYP1A1*2A, GSTM1, GSTP1, GSTT1, and MPO possibly influenced the relationship between TDA in plasma and urine. CONCLUSION Our results show, for the first time, genetic modification on the human TDI metabolism. The findings suggest that GSTP1 genotype should be considered when evaluating biomarkers of TDI exposure in urine and plasma. Moreover, the results support earlier findings of GSTP1 105 Val as protective against TDI-related asthma.
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Bendaly J, Doll MA, Millner LM, Metry KJ, Smith NB, Pierce WM, Hein DW. Differences between human slow N-acetyltransferase 2 alleles in levels of 4-aminobiphenyl-induced DNA adducts and mutations. Mutat Res 2009; 671:13-9. [PMID: 19682468 DOI: 10.1016/j.mrfmmm.2009.08.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2009] [Revised: 07/28/2009] [Accepted: 08/04/2009] [Indexed: 12/25/2022]
Abstract
Aromatic amines such as 4-aminobiphenyl (ABP) require biotransformation to exert their carcinogenic effects. Genetic polymorphisms in biotransformation enzymes such as N-acetyltransferase 2 (NAT2) may modify cancer risk following exposure. Nucleotide excision repair-deficient Chinese hamster ovary (CHO) cells stably transfected with human cytochrome P4501A1 (CYP1A1) and a single copy of either NAT2*4 (rapid acetylator), NAT2*5B (common Caucasian slow acetylator), or NAT2*7B (common Asian slow acetylator) alleles (haplotypes) were treated with ABP to test the effect of NAT2 polymorphisms on DNA adduct formation and mutagenesis. ABP N-acetyltransferase catalytic activities were detectable only in cell lines transfected with NAT2 and were highest in cells transfected with NAT2*4, lower in cells transfected with NAT2*7B, and lowest in cells transfected with NAT2*5B. Following ABP treatment, N-(deoxyguanosin-8-yl)-4-aminobiphenyl (dG-C8-ABP) was the primary adduct formed. Cells transfected with both CYP1A1 and NAT2*4 showed the highest concentration-dependent cytotoxicity, hypoxanthine phosphoribosyl transferase (hprt) mutants, and dG-C8-ABP adducts. Cells transfected with CYP1A1 and NAT2*7B showed lower levels of cytotoxicity, hprt mutagenesis, and dG-C8-ABP adducts. Cells transfected with CYP1A1 only or cells transfected with both CYP1A1 and NAT2*5B did not induce cytotoxicity, hprt mutagenesis or dG-C8-ABP adducts. ABP-DNA adduct levels correlated very highly (r>0.96) with ABP-induced hprt mutant levels following each treatment. The results of the present study suggest that investigations of NAT2 genotype or phenotype associations with disease or toxicity could be more precise and reproducible if heterogeneity within the "slow" NAT2 acetylator phenotype is considered and incorporated into the study design.
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Affiliation(s)
- Jean Bendaly
- Department of Pharmacology & Toxicology, University of Louisville School of Medicine, Louisville, KY 40292, United States
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16
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Stiborová M, Dracínská H, Martínková M, Mizerovská J, Hudecek J, Hodek P, Liberda J, Frei E, Schmeiser HH, Phillips DH, Arlt VM. 3-aminobenzanthrone, a human metabolite of the carcinogenic environmental pollutant 3-nitrobenzanthrone, induces biotransformation enzymes in rat kidney and lung. Mutat Res 2009; 676:93-101. [PMID: 19398038 DOI: 10.1016/j.mrgentox.2009.04.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2008] [Revised: 02/05/2009] [Accepted: 04/12/2009] [Indexed: 11/30/2022]
Abstract
3-aminobenzanthrone (3-ABA) is the metabolite of the carcinogenic air pollutant 3-nitrobenzanthrone (3-NBA). 3-ABA was investigated for its ability to induce cytochrome P450 1A1 (CYP1A1) and NAD(P)H:quinone oxidoreductase (NQO1) in kidney and lung of rats, and for the influence of such induction on DNA adduct formation by 3-ABA and 3-NBA. NQO1 is the enzyme that reduces 3-NBA to N-hydroxy-3-aminobenzanthrone (N-OH-3-ABA) and CYP1A enzymes oxidize 3-ABA to the same intermediate. When activated by cytosolic and and/or microsomal fractions isolated from rat lung, the target organ for 3-NBA carcinogenicity, and kidney, both compounds generated the same DNA-adduct pattern, consisting of five adducts. When pulmonary cytosols isolated from rats that had been treated i.p. with 40 mg/kg bw of 3-ABA were incubated with 3-NBA, DNA adduct formation was up to 1.7-fold higher than in incubations with cytosols from control animals. This increase corresponded to an increase in protein level and enzymatic activity of NQO1. In contrast, no induction of NQO1 expression by 3-ABA treatment was found in the kidney. Incubations of 3-ABA with renal and pulmonary microsomes of 3-ABA-treated rats led to an increase of up to a 4.5-fold in DNA-adduct formation relative to controls. The stimulation of DNA-adduct formation correlated with a higher protein expression and activity of CYP1A1 induced by 3-ABA. These results show that by inducing lung and kidney CYP1A1 and NQO1, 3-ABA increases its own enzymatic activation as well as that of the environmental pollutant, 3-NBA, thereby enhancing the genotoxic and carcinogenic potential of both compounds.
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Affiliation(s)
- Marie Stiborová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic.
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17
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Davies MJ, Hawkins CL, Pattison DI, Rees MD. Mammalian heme peroxidases: from molecular mechanisms to health implications. Antioxid Redox Signal 2008; 10:1199-234. [PMID: 18331199 DOI: 10.1089/ars.2007.1927] [Citation(s) in RCA: 423] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A marked increase in interest has occurred over the last few years in the role that mammalian heme peroxidase enzymes, primarily myeloperoxidase, eosinophil peroxidase, and lactoperoxidase, may play in both disease prevention and human pathologies. This increased interest has been sparked by developments in our understanding of polymorphisms that control the levels of these enzymes, a greater understanding of the basic chemistry and biochemistry of the oxidants formed by these species, the development of specific biomarkers that can be used in vivo to detect damage induced by these oxidants, the detection of active forms of these peroxidases at most, if not all, sites of inflammation, and a correlation between the levels of these enzymes and a number of major human pathologies. This article reviews recent developments in our understanding of the enzymology, chemistry, biochemistry and biologic roles of mammalian peroxidases and the oxidants that they generate, the potential role of these oxidants in human disease, and the use of the levels of these enzymes in disease prognosis.
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Affiliation(s)
- Michael J Davies
- The Heart Research Institute, Camperdown, University of Sydney, Sydney, Australia., Faculty of Medicine, University of Sydney, Sydney, Australia.
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18
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Broberg K, Tinnerberg H, Axmon A, Warholm M, Rannug A, Littorin M. Influence of genetic factors on toluene diisocyanate-related symptoms: evidence from a cross-sectional study. Environ Health 2008; 7:15. [PMID: 18447907 PMCID: PMC2424047 DOI: 10.1186/1476-069x-7-15] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Accepted: 04/30/2008] [Indexed: 05/26/2023]
Abstract
BACKGROUND Toluene diisocyanate (TDI) is a highly reactive compound used in the production of, e.g., polyurethane foams and paints. TDI is known to cause respiratory symptoms and diseases. Because TDI causes symptoms in only a fraction of exposed workers, genetic factors may play a key role in disease susceptibility. METHODS Workers (N = 132) exposed to TDI and a non-exposed group (N = 114) were analyzed for genotype (metabolising genes: CYP1A1*2A, CYP1A1*2B, GSTM1*O, GSTM3*B, GSTP1 I105V, GSTP1 A114V, GSTT1*O, MPO -463, NAT1*3, *4, *10, *11, *14, *15, NAT2*5, *6, *7, SULT1A1 R213H; immune-related genes: CCL5 -403, HLA-DQB1*05, TNF -308, TNF -863) and symptoms of the eyes, upper and lower airways (based on structured interviews). RESULTS For three polymorphisms: CYP1A1*2A, CYP1A1*2B, and TNF -308 there was a pattern consistent with interaction between genotype and TDI exposure status for the majority of symptoms investigated, although it did reach statistical significance only for some symptoms: among TDI-exposed workers, the CYP1A1 variant carriers had increased risk (CYP1A1*2A and eye symptoms: variant carriers OR 2.0 95% CI 0.68-6.1, p-value for interaction 0.048; CYP1A1*2B and wheeze: IV carriers OR = 12, 1.4-110, p-value for interaction 0.057). TDI-exposed individuals with TNF-308 A were protected against the majority of symptoms, but it did not reach statistical significance. In the non-exposed group, however, TNF -308 A carriers showed higher risk of the majority of symptoms (eye symptoms: variant carriers OR = 2.8, 1.1-7.1, p-value for interaction 0.12; dry cough OR = 2.2, 0.69-7.2, p-value for interaction 0.036). Individuals with SULT1A1 213H had reduced risk both in the exposed and non-exposed groups. Other polymorphisms, showed associations to certain symptoms: among TDI-exposed,NAT1*10 carriers had a higher risk of eye symptoms and CCL5 -403 AG+AA as well as HLA-DQB1 *05 carriers displayed increased risk of symptoms of the lower airways. GSTM1, GSTM3 and GSTP1 only displayed effects on symptoms of the lower airways in the non-exposed group. CONCLUSION Specific gene-TDI interactions for symptoms of the eyes and lower airways appear to exist. The results suggest different mechanisms for TDI- and non-TDI-related symptoms of the eyes and lower airways.
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Affiliation(s)
- Karin Broberg
- Department of Occupational and Environmental medicine, Lund University, Sweden
| | - Håkan Tinnerberg
- Department of Occupational and Environmental medicine, Lund University, Sweden
| | - Anna Axmon
- Department of Occupational and Environmental medicine, Lund University, Sweden
| | - Margareta Warholm
- Department of Work Environment Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Sweden
| | - Agneta Rannug
- Department of Work Environment Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Sweden
| | - Margareta Littorin
- Department of Occupational and Environmental medicine, Lund University, Sweden
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19
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Stiborová M, Arlt VM, Henderson CJ, Wolf CR, Kotrbová V, Moserová M, Hudeček J, Phillips DH, Frei E. Role of hepatic cytochromes P450 in bioactivation of the anticancer drug ellipticine: Studies with the hepatic NADPH:Cytochrome P450 reductase null mouse. Toxicol Appl Pharmacol 2008; 226:318-27. [DOI: 10.1016/j.taap.2007.09.017] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Revised: 09/14/2007] [Accepted: 09/19/2007] [Indexed: 10/22/2022]
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20
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Abstract
The aim of this study is to summarize the available molecular epidemiologic studies of lung cancer and metabolic genes, such as NAD(P)H quinone reductase 1 (NQO1) and myeloperoxidase (MPO). NQO1 plays a dual role in the detoxification and activation of procarcinogens whereas MPO has Phase I activity by converting lipophilic carcinogens into hydrophilic forms. Variant genotypes of both NQO1 Pro187 Ser and MPO G-463A polymorphisms may be related to low enzyme activity. The Pro/Ser and Ser/Ser genotypes combined of NQO1 was significantly associated with decreased risk of lung cancer in Japanese [random effects odds ratio (OR) = 0.70, 95% confidence interval (CI) = 0.56-0.88] among whom the variant allele is common. The variant genotype of MPO was associated with decreased risk of lung cancer among Caucasians (random effects OR = 0.70, 95% CI = 0.47-1.04). Gene-environment interactions in both polymorphisms may be hampered by inaccurate categorization of tobacco exposure. Evidence on gene-gene interactions is extremely limited. As lung cancer is a multifactorial disease, an improved understanding of such interactions may help identify individuals at risk for developing lung cancer. Such a study should include larger sample size and other polymorphisms in the metabolism of tobacco-derived carcinogens and address interactions with smoking status. The effects of polymorphisms are best represented by their haplotypes. In future studies on lung cancer, the development of haplotype-based approaches will facilitate the evaluation of haplotypic effects, either for selected polymorphisms physically close to each other or for multiple genes within the same drug-metabolism pathway.
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Affiliation(s)
- Chikako Kiyohara
- Department of Preventive Medicine, Graduate School of Medical Sciences, Kyushu University, Maidashi, Fukuoka, Japan
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21
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Kurian JR, Longlais BJ, Trepanier LA. Discovery and characterization of a cytochrome b5 variant in humans with impaired hydroxylamine reduction capacity. Pharmacogenet Genomics 2007; 17:597-603. [PMID: 17622936 DOI: 10.1097/fpc.0b013e328011aaff] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES We have shown that cytochrome b5 (cyt b5), along with its reductase, NADH cytochrome b5 reductase (b5R), is capable of direct xenobiotic biotransformation. We hypothesized that functionally significant genetic variability in cyt b5 could be found in healthy individuals. BASIC METHODS Cyt b5 cDNAs were prepared from peripheral blood mononuclear cells from 63 individuals. MAIN RESULTS One individual was heterozygous for a sequence variant in cyt b5 (A178G), with a predicted amino acid substitution of T60A. This variant, when expressed in Escherichia. coli, maintained a similar Vmax for the hydroxylamines of sulfamethoxazole, 4-aminobiphenyl, and 2-amino-l-methyl-6-phenylimidazo[4,5-b] pyridine (PhIP), compared with wild type cyt b5, with a modestly increased Km (2 to 3.5-fold) for each substrate. When expressed in a mammalian system (HeLa cells), however, T60A was associated with a 70% reduction in cyt b5 protein expression compared with wild type. mRNA expression for both isoforms were comparable in HeLa cells, and translation of these mRNAs in a rabbit reticulocyte lysate system with inhibited proteasomal machinery were also similar. Incubation of these translated enzymes with uninhibited rabbit reticulocyte lysate, however, indicated greater susceptibility of T60A to proteasomal degradation. CONCLUSIONS These data indicate that a naturally occurring variant in cyt b5, T60A, leads to modestly altered affinity for hydroxylamine substrates and dramatically reduced cyt b5 expression. Work is underway to determine the prevalence of this and other variants in cyt b5 or b5R in a larger population, and to determine the association of such variants with differences in hydroxylamine reduction in vivo.
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Affiliation(s)
- Joseph R Kurian
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, USA
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22
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Littorin M, Hou S, Broberg K, Björk J, Fält S, Abdoulaye G, Kalemba M, Ryk C, Skerfving S. Influence of polymorphic metabolic enzymes on biotransformation and effects of diphenylmethane diisocyanate. Int Arch Occup Environ Health 2007; 81:429-41. [PMID: 17676332 DOI: 10.1007/s00420-007-0232-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Accepted: 07/11/2007] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To identify effect modification produced by genetic traits found in metabolic enzymes, to investigate how these affect the levels of different biomarkers of sprayed and thermo-degraded polyurethane (PUR) based on 4,4'-diphenylmethane diisocyanate (MDI) and to determine how associated respiratory disorders are affected. METHODS Two partly overlapping groups of 141 and 158 factory employees exposed to sprayed or heated MDI-PUR glue were examined in years 0 and 2, respectively, for occurrence of polymorphisms in five genes (N-acetyltransferase NAT2 and the glutathione S-transferases GSTM1, GSTM3, GSTP1 [codon 105 and 114] and GSTT1) on the basis of the polymerase chain reaction, exposure biomarkers in plasma and urine (P- and U-MDX), by means of gas chromatography-mass spectrometry, specific serum IgG antibodies against MDI (S-IgG-MDI) by means of ELISA, total S-IgE, symptoms in the eyes, nose and lower airways as assessed by questionnaire and interview, and lung function as measured by spirometry. RESULTS Both the GSTP1 (105) isoleucine/isoleucine and GSTP1 (114) alanine/alanine genotypes showed higher levels of U-MDX than the other genotypes and the GSTP1 (114) genotype modified the P-MDX/U-MDX relationship. GSTP1 (105) isoleucine/isoleucine was found to be associated with lower levels of S-IgG-MDI and fewer eye symptoms, but with an increased risk of symptoms in the airways, as well as with atopy. Presence of the GSTT1 gene resulted in somewhat lower lung function levels than did the null genotype. A slow NAT2 acetylating capacity was associated with lower P- and U-MDX and S-IgG-MDI levels, and better lung function, but a higher risk of eye and airway symptoms. Analysing the effects of combinations of the different genes provided no further information. CONCLUSIONS Although our study has clear limitations, it reveals various effect modifications produced by the GST and NAT2 genotypes. Gene-environment interactions are highly complex. Further research is needed to obtain a more comprehensive understanding of them.
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Affiliation(s)
- Margareta Littorin
- Department of Occupational and Environmental Medicine, University Hospital, 221 85 Lund, Sweden.
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23
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Kurian JR, Chin NA, Longlais BJ, Hayes KL, Trepanier LA. Reductive detoxification of arylhydroxylamine carcinogens by human NADH cytochrome b5 reductase and cytochrome b5. Chem Res Toxicol 2007; 19:1366-73. [PMID: 17040106 PMCID: PMC2516554 DOI: 10.1021/tx060106t] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Heterocyclic and aromatic amine carcinogens are thought to lead to tumor initiation via the formation of DNA adducts, and bioactivation to arylhydroxylamine metabolites is necessary for reactivity with DNA. Carcinogenic arylhydroxylamine metabolites are cleared by a microsomal, NADH-dependent, oxygen-insensitive reduction pathway in humans, which may be a source of interindividual variability in response to aromatic amine carcinogens. The purpose of this study was to characterize the identity of this reduction pathway in human liver. On the basis of our findings with structurally similar arylhydroxylamine metabolites of therapeutic drugs, we hypothesized that the reductive detoxification of arylhydroxylamine carcinogens was catalyzed by NADH cytochrome b5 reductase (b5R) and cytochrome b5 (cyt b5). We found that reduction of the carcinogenic hydroxylamines of the aromatic amine 4-aminobiphenyl (4-ABP; found in cigarette smoke) and the heterocyclic amine 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP; found in grilled meats) was indeed catalyzed by a purified system containing only human b5R and cyt b5. Specific activities were 56-346-fold higher in the purified system as compared to human liver microsomes (HLM), with similar Michaelis-Menten constants (K(m) values) in both systems. The stoichiometry for b5R and cyt b5 that yielded the highest activity in the purified system was also similar to that found in native HLM ( approximately 1:8 to 1:10). Polyclonal antisera to either b5R or cyt b5 significantly inhibited N-hydroxy-4-aminobiphenyl (NHOH-4-ABP) reduction by 95 and 89%, respectively, and immunoreactive cyt b5 protein content in individual HLM was significantly correlated with individual reduction of both NHOH-4-ABP and N-hydroxy-PhIP (NHOH-PhIP). Finally, titration of HLM into the purified b5R/cyt b5 system did not enhance the efficiency of reduction activity. We conclude that b5R and cyt b5 are together solely capable of the reduction of arylhydroxylamine carcinogens, and we further hypothesize that this pathway may be a source of individual variability with respect to cancer susceptibility following 4-ABP or PhIP exposure.
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Affiliation(s)
| | | | | | | | - Lauren A. Trepanier
- Address correspondence to: Lauren A. Trepanier, Department of Medical Sciences, UW-Madison School of Veterinary Medicine, 2015 Linden Dr, Madison, WI, 53706. Tel. 608 265−9022; Fax 608 265−8020;
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24
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Jiang Z, Dragin N, Jorge-Nebert LF, Martin MV, Guengerich FP, Aklillu E, Ingelman-Sundberg M, Hammons GJ, Lyn-Cook BD, Kadlubar FF, Saldana SN, Sorter M, Vinks AA, Nassr N, von Richter O, Jin L, Nebert DW. Search for an association between the human CYP1A2 genotype and CYP1A2 metabolic phenotype. Pharmacogenet Genomics 2006; 16:359-67. [PMID: 16609368 DOI: 10.1097/01.fpc.0000204994.99429.46] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The genotype responsible for more than 60-fold interindividual differences in human hepatic CYP1A2 constitutive expression is not understood. Resequencing the human CYP1A1_CYP1A2 locus (39.6 kb) in five major geographically isolated subgroups recently led to the identification of 85 single nucleotide polymorphisms (SNPs), 57 of which were double-hit SNPs. Here, we attempted to correlate the CYP1A2 genotype with a metabolic phenotype. We chose 16 SNPs (all having a minor allele frequency > or =0.05 in Caucasians) to genotype 32 DNA samples (26 Caucasians, six Ethiopians) in which CYP1A2 metabolism had previously been determined. From 280 subjects (five locations worldwide) that had been CYP1A2-phenotyped, we genotyped the 10 highest, 14 lowest and eight intermediate DNA samples. Although no SNP was significant (P<0.05), possibly due to the small sample size, we found a trend for several of the six SNPs across the CYP1A2 linkage disequilibrium block associated with the trait. Five CYP1A2 haplotypes were inferred, two of which had not previously been reported; haplotype 1A2H10 showed the greatest association with CYP1A2 activity. Regulatory sequences responsible for the large interindividual differences in hepatic CYP1A2 gene basal expression might reside, in part, with some of these CYP1A2 SNPS but, in large part, might be located either cis (in nearby sequences not yet haplotyped) or trans in that they are not linked to the gene. We conclude that no SNP or haplotype in the CYP1A2 gene has yet been identified that can unequivocally be used to predict the metabolic phenotype in any individual patient.
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Affiliation(s)
- Zhengwen Jiang
- Department of Environmental Health and Center for Environmental Genetics (CEG), University of Cincinnati Medical Center, Cincinnati, OH 45267, USA
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25
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Arlt VM, Henderson CJ, Wolf CR, Schmeiser HH, Phillips DH, Stiborova M. Bioactivation of 3-aminobenzanthrone, a human metabolite of the environmental pollutant 3-nitrobenzanthrone: evidence for DNA adduct formation mediated by cytochrome P450 enzymes and peroxidases. Cancer Lett 2006; 234:220-31. [PMID: 15885895 DOI: 10.1016/j.canlet.2005.03.035] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2005] [Revised: 03/20/2005] [Accepted: 03/24/2005] [Indexed: 11/28/2022]
Abstract
3-Nitrobenzanthrone (3-NBA) is a suspected human carcinogen found in diesel exhaust and ambient air pollution. The main metabolite of 3-NBA, 3-aminobenzanthrone (3-ABA), was detected in the urine of salt mining workers occupationally exposed to diesel emissions. We evaluated the role of hepatic cytochrome P450 (CYP) enzymes in the activation of 3-ABA in vivo by treating hepatic cytochrome P450 oxidoreductase (POR)-null mice and wild-type littermates intraperitoneally with 0.2 and 2mg/kg body weight of 3-ABA. Hepatic POR-null mice lack POR-mediated CYP enzyme activity in the liver. Using the (32)P-postlabelling method, multiple 3-ABA-derived DNA adducts were observed in liver DNA from wild-type mice, qualitatively similar to those formed in incubations using human hepatic microsomes. The adduct pattern was also similar to those formed by the nitroaromatic counterpart 3-NBA and which derive from reductive metabolites of 3-NBA bound to purine bases in DNA. DNA binding by 3-ABA in the livers of the null mice was undetectable at the lower dose and substantially reduced (by up to 80%), relative to wild-type mice, at the higher dose. These data indicate that POR-mediated CYP enzyme activities are important for the oxidative activation of 3-ABA in livers, confirming recent results indicating that CYP1A1 and -1A2 are mainly responsible for the metabolic activation of 3-ABA in human hepatic microsomes. No difference in DNA binding was found in kidney and bladder between null and wild-type mice, suggesting that cells in these extrahepatic organs have the metabolic capacity to oxidize 3-ABA to species forming the same 3-ABA-derived DNA adducts, independently from the CYP-mediated oxidation in the liver. We determined that different model peroxidases are able to catalyse DNA adduct formation by 3-ABA in vitro. Horseradish peroxidase (HRP), lactoperoxidase (LPO), myeloperoxidase (MPO), and prostaglandin H synthase (PHS) were all effective in activating 3-ABA in vitro, forming DNA adducts qualitatively similar to those formed in vivo in mice treated with 3-ABA and to those found in DNA reacted with N-hydroxy-3-aminobenzanthrone (N-OH-ABA). Collectively, these results suggest that both CYPs and peroxidases may play an important role in metabolizing 3-ABA to reactive DNA adduct forming species.
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Affiliation(s)
- Volker M Arlt
- Section of Molecular Carcinogenesis, Institute of Cancer Research, Brookes Lawley Building, Sutton, Surrey SM2 5NG, UK.
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26
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Stiborová M, Poljaková J, Ryslavá H, Dracínský M, Eckschlager T, Frei E. Mammalian peroxidases activate anticancer drug ellipticine to intermediates forming deoxyguanosine adducts in DNA identical to those foundin vivo and generated from 12-hydroxyellipticine and 13-hydroxyellipticine. Int J Cancer 2006; 120:243-51. [PMID: 17066455 DOI: 10.1002/ijc.22247] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Ellipticine is a potent antineoplastic agent, whose mode of action is considered to be based mainly on DNA intercalation, inhibition of topoisomerase II and cytochrome P450-mediated formation of covalent DNA adducts. This is the first report on the molecular mechanism of ellipticine oxidation by peroxidases (human myeloperoxidase, human and ovine cyclooxygenases, bovine lactoperoxidase, horseradish peroxidase) to species forming ellipticine-DNA adducts. Using NMR spectroscopy, the structures of 2 ellipticine metabolites were identified; the major product is the ellipticine dimer, in which the 2 ellipticine skeletons are connected via N(6) of the pyrrole ring of one ellipticine molecule and C9 in the second one. The minor metabolite is ellipticine N(2)-oxide. Using (32)P-postlabeling and [(3)H]-labeled ellipticine, we showed that ellipticine binds covalently to DNA after its activation by peroxidases. The DNA adduct pattern induced by ellipticine consisted of a cluster of up to 4 adducts. The 2 adducts are indistinguishable from the 2 major adducts generated between deoxyguanosine in DNA and either 13-hydroxy- or 12-hydroxyellipticine or in rats treated with ellipticine, or if ellipticine was activated with human hepatic and renal microsomes. The results presented here are the first characterization of the peroxidase-mediated oxidative metabolites of ellipticine and we have proposed species, 2 carbenium ions, ellipticine-13-ylium and ellipticine-12-ylium, as reactive species generating 2 major DNA adducts seen in vivo in rats treated with ellipticine. The study forms the basis to further predict the susceptibility of human cancers to ellipticine.
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Affiliation(s)
- Marie Stiborová
- Department of Biochemistry, Faculty of Science, Charles University, Prague, Czech Republic.
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27
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Abstract
Arylamines and heterocyclic arylamines (HAAs) are of particular interest because of demonstrated carcinogenicity in animals and humans and the broad exposure to many of these compounds. The activation of these, and also some arylamine drugs, involves N-hydroxylation, usually by cytochrome P450 (P450). P450 1A2 plays a prominent role in these reactions. However, P450 1A1 and 1B1 and other P450s are also important in humans as well as experimental animals. Some arylamines (including drugs) are N-hydroxylated predominantly by P450s other than those in Family 1. Other oxygenases can also have roles. An important issue is extrapolation between species in predicting cancer risks, as shown by the low rates of HAA activation by rat P450 1A2 and low levels of P450 1A2 expression in some nonhuman primates.
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Affiliation(s)
- Donghak Kim
- Department of Biochemistry and Center in Molecular Toxicology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, USA
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Schabath MB, Delclos GL, Martynowicz MM, Greisinger AJ, Lu C, Wu X, Spitz MR. Opposing effects of emphysema, hay fever, and select genetic variants on lung cancer risk. Am J Epidemiol 2005; 161:412-22. [PMID: 15718477 DOI: 10.1093/aje/kwi063] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The authors compared histories of nonmalignant respiratory diseases (asthma, bronchitis, emphysema, hay fever, and pneumonia) in 1,553 lung cancer patients and 1,375 healthy controls enrolled in a Texas case-control study from 1995 to 2003. They incorporated data on two biologically relevant polymorphic genes, matrix metalloproteinase-1 and myeloperoxidase. Emphysema was associated with a statistically significant increased lung cancer risk (odds ratio (OR) = 2.87, 95% confidence interval (CI): 2.20, 3.76), while hay fever had a significant protective effect (OR = 0.58, 95% CI: 0.48, 0.70). Odds ratios were consistent after exclusion of respiratory disease diagnoses made up to 10 years before interview. There was little association between other respiratory diseases and lung cancer risk. Among carriers of "protective" genotypes, emphysema was associated with a 1.7-fold increased risk (95% CI: 0.84, 3.50), as compared with the substantially higher risk for persons possessing one (OR = 4.98, 95% CI: 2.94, 8.44) or two (OR = 4.23, 95% CI: 1.84, 9.73) "adverse" genotypes. For hay fever, significantly decreased risks were evident with one (OR = 0.32, 95% CI: 0.21, 0.50) or two (OR = 0.35, 95% CI: 0.19, 0.66) protective genotypes as compared with none (OR = 0.69, 95% CI: 0.30, 1.59). The biologic role of respiratory disease in lung cancer is unclear. Further study may yield new insights for identification of susceptible subgroups.
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Affiliation(s)
- Matthew B Schabath
- Department of Epidemiology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
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Yang M, Coles BF, Caporaso NE, Choi Y, Lang NP, Kadlubar FF. Lack of association between Caucasian lung cancer risk and O6-methylguanine-DNA methyltransferase-codon 178 genetic polymorphism. Lung Cancer 2004; 44:281-6. [PMID: 15140540 DOI: 10.1016/j.lungcan.2003.12.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2003] [Revised: 11/25/2003] [Accepted: 12/04/2003] [Indexed: 11/19/2022]
Abstract
The formation of DNA adducts is thought to be a critical step for the induction of chemically induced cancer. O(6)-Methylguanine-DNA methyltransferase (MGMT) is a ubiquitously expressed enzyme that repairs DNA adducts formed by alkylating carcinogens. Thus, genetic polymorphisms of the MGMT that could result in differences in MGMT activity are potential risk factors for cancer. In the present study, we established a convenient and reliable genotyping method for the MGMT codon 178 polymorphism, a Lys (AAG) to Arg (AGG) substitution, using restriction fragment length polymorphism (RFLP), and studied differences in the distribution of this polymorphism in 92 Caucasian lung cancer patients and 85 controls. Frequencies of the "A" and "G" alleles (MGMT codon 178, AAG and AGG, respectively) were 0.91 and 0.09, respectively. The genetic polymorphism of the MGMT codon 178 was linked with that of the MGMT codon 143 (P < 0.05). The distribution of the MGMT codon 178 genetic polymorphism was not significantly different between lung cancer patients and controls. Thus, our study suggests that the MGMT codon 178 (and possibly 143) polymorphisms do not appear to markedly affect lung cancer risk for this population. In addition, we found an apparent 10bp-deletion in the intron before exon 5 by DNA sequencing. Because this "deletion" was observed in all sequenced samples (N = 20), the previously reported human (Caucasian) MGMT gene sequence should be revised to exclude this 10bp segment.
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Affiliation(s)
- Mihi Yang
- Department of Preventive Medicine, Cancer Research Institute, College of Medicine, Seoul National University, Chongno-go, South Korea.
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30
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Abstract
The xenobiotic-metabolizing P450s have been extensively studied for their ability to metabolize endogenous and exogenous chemicals. The latter include drugs and dietary and environmentally derived toxicants and carcinogens. These enzymes also metabolize endogenous steroids and fatty acids. P450s are thought to be required for efficient removal of most xenobiotics from the body and to be responsible for the hazardous effects of toxicants and carcinogens based on their ability to convert chemicals to electrophilic metabolites that can cause cellular damage and gene mutations. P450 catalytic activities have been extensively studied in vitro and in cell culture, yielding considerable information on their mechanisms of catalysis, substrate specificities, and metabolic products. Targeted gene disruption has been used to determine the roles of P450s in intact animals and their contributions to the mechanisms of toxicity and carcinogenesis. The P450s chosen for study, CYP1A1, CYP1B1, CYP1A2, and CYP2E1, are conserved in mammals and are known to metabolize most toxicants and chemical carcinogens. Mice lacking expression of these enzymes do not differ from wild-type mice, indicating that these P450s are not required for development and physiological homeostasis. However, the P450 null mice have altered responses to the toxic and carcinogenic effects of chemicals as compared with wild-type mice. These studies establish that P450s mediate the adverse effects of drugs and dietary, environmental, and industrial chemicals and serve to validate molecular epidemiology studies that seek to determine links between P450 polymorphisms and susceptibility to chemically associated diseases. More recently, P450 humanized mice have been produced.
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Affiliation(s)
- Frank J Gonzalez
- Building 37, Room 3E-24, Laboratory of Metabolism, National Cancer Institute, Bethesda, MD 20892, USA.
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31
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Pfeifer GP, Denissenko MF, Olivier M, Tretyakova N, Hecht SS, Hainaut P. Tobacco smoke carcinogens, DNA damage and p53 mutations in smoking-associated cancers. Oncogene 2002; 21:7435-51. [PMID: 12379884 DOI: 10.1038/sj.onc.1205803] [Citation(s) in RCA: 741] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
It is estimated that cigarette smoking kills over 1 000 000 people each year by causing lung cancer as well as many other neoplasmas. p53 mutations are frequent in tobacco-related cancers and the mutation load is often higher in cancers from smokers than from nonsmokers. In lung cancers, the p53 mutational patterns are different between smokers and nonsmokers with an excess of G to T transversions in smoking-associated cancers. The prevalence of G to T transversions is 30% in smokers' lung cancer but only 12% in lung cancers of nonsmokers. A similar trend exists, albeit less marked, in laryngeal cancers and in head and neck cancers. This type of mutation is infrequent in most other tumors aside from hepatocellular carcinoma. At several p53 mutational hotspots common to all cancers, such as codons 248 and 273, a large fraction of the mutations are G to T events in lung cancers but are almost exclusively G to A transitions in non-tobacco-related cancers. Two important classes of tobacco smoke carcinogens are the polycyclic aromatic hydrocarbons (PAH) and the nicotine-derived nitrosamines. Recent studies have indicated that there is a strong coincidence of G to T transversion hotspots in lung cancers and sites of preferential formation of PAH adducts along the p53 gene. Endogenously methylated CpG dinucleotides are the preferred sites for G to T transversions, accounting for more than 50% of such mutations in lung tumors. The same dinucleotide, when present within CpG-methylated mutational reporter genes, is the target of G to T transversion hotspots in cells exposed to the model PAH compound benzo[a]pyrene-7,8-diol-9,10-epoxide. As summarized here, a number of other tobacco smoke carcinogens also can cause G to T transversion mutations. The available data suggest that p53 mutations in lung cancers can be attributed to direct DNA damage from cigarette smoke carcinogens rather than to selection of pre-existing endogenous mutations.
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Affiliation(s)
- Gerd P Pfeifer
- Division of Biology, Beckman Research Institute of the City of Hope, Duarte, California, CA 91010, USA.
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32
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Koc H, Swenberg JA. Applications of mass spectrometry for quantitation of DNA adducts. J Chromatogr B Analyt Technol Biomed Life Sci 2002; 778:323-43. [PMID: 12376138 DOI: 10.1016/s1570-0232(02)00135-6] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
DNA adducts are formed when electrophilic molecules or free radicals attack DNA. 32P-postlabeling has been the most commonly used assay for quantitation of DNA adducts due mainly to its excellent sensitivity that allows quantitation at concentrations as low as approximately 1 adduct per 10(9) normal bases. Such methods, however, do not have the specificity desired for accurate and reliable quantitation, and are prone to produce false positives and artifacts. In the last decade, mass spectrometry in combination with liquid and gas chromatography has presented itself as a good alternative to these techniques since it can satisfy the need for specificity and reliability through the use of stable isotope-labeled internal standards and highly specific detection modes such as selected reaction monitoring and high-resolution mass spectrometry. In this article, the contribution of mass spectrometry to the quantitation of DNA adducts is reviewed with special emphasis on unique applications of mass spectrometry in the area of DNA adduct quantitation and recent applications with improvements in sensitivity.
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Affiliation(s)
- Hasan Koc
- Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, NC 27599-7431, USA
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Yang M, Coles BF, Delongchamp R, Lang NP, Kadlubar FF. Effects of the ADH3, CYP2E1, and GSTP1 genetic polymorphisms on their expressions in Caucasian lung tissue. Lung Cancer 2002; 38:15-21. [PMID: 12367788 DOI: 10.1016/s0169-5002(02)00150-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Individual differences in lung cancer susceptibility should be considered for effective lung cancer prevention. We investigated the CYP2E1, ADH3, and GSTP1 genetic polymorphisms that biotransform xenobiotic carcinogens, and variations of their enzyme activity in Caucasian lung tissues (N=28), and found a variant distribution in pulmonary ADH and CYP2E1 activity. The ADH3*1/*1 subjects (N=8) showed significantly higher ADH activity than ADH3*2/*2 (N=3) subjects (P<0.01). On the other hand, we found a 5-fold variation in the pulmonary CYP2E1 activity using a sensitive HLPC/EC based technique. A subject with the CYP2E1-c/t allele showed 2-fold higher CYP2E1 activity than subjects with the c/c allele (N=14). GSTP1 expression comprised 83% of the total pulmonary GSTs. However, neither the GSTP1 polymorphism, nor other lifestyle factors, such as age, gender, smoking status, were found to be associated with pulmonary GST expression. In conclusion, subjects with the ADH3*1 allele showed higher ADH activity and acetaldehyde-DNA adducts in lung than other subjects; thus, the ADH3*1 allele could be considered a risk factor for lung cancer.
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Affiliation(s)
- Mihi Yang
- Department of Preventive Medicine, Cancer Research Institute, College of Medicine, Seoul National University, 28 Yongon-Dong, Chongno-Gu, 110-799, Seoul, Republic of Korea.
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Abstract
Arylamines and nitroarenes are very important intermediates in the industrial manufacture of dyes, pesticides and plastics, and are significant environmental pollutants. The metabolic steps of N-oxidation and nitroreduction to yield N-hydroxyarylamines are crucial for the toxic properties of arylamines and nitroarenes. Nitroarenes are reduced by microorganisms in the gut or by nitroreductases and aldehyde dehydrogenase in hepatocytes to nitrosoarenes and N-hydroxyarylamines. N-Hydroxyarylamines can be further metabolized to N-sulphonyloxyarylamines, N-acetoxyarylamines or N-hydroxyarylamine N-glucuronide. These highly reactive intermediates are responsible for the genotoxic and cytotoxic effects of this class of compounds. N-Hydroxyarylamines can form adducts with DNA, tissue proteins, and the blood proteins albumin and haemoglobin in a dose-dependent manner. DNA and protein adducts have been used to biomonitor humans exposed to such compounds. All these steps are dependent on enzymes, which are present in polymorphic forms. This article reviews the metabolism of arylamines and nitroarenes and the biomonitoring studies performed in animals and humans exposed to these substances.
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Affiliation(s)
- Gabriele Sabbioni
- Walther-Straub-Institut für Pharmakologie und Toxikologie, Ludwig-Maximilians-Universität München, Nussbaumstrasse 26, D-80336 München, Germany.
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35
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Siraki AG, Chan TS, Galati G, Teng S, O'Brien PJ. N-oxidation of aromatic amines by intracellular oxidases. Drug Metab Rev 2002; 34:549-64. [PMID: 12214666 DOI: 10.1081/dmr-120005657] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The introduction includes a literature review of DNA reactive species and DNA adduct formation that results from aromatic amine N-oxidation catalyzed by hepatic cytochrome P450 vs. that catalyzed by nonhepatic peroxidases. Experimental evidence is then described for a novel oxidative stress mechanism involving prooxidant N-cation radical formation by both oxidases, which is proposed as a contributing mechanism for aromatic amine induced cytotoxicity and carcinogenesis. Aromatic amine N-cation radicals formed by peroxidases were found to cooxidize GSH or NADH and form reactive oxygen species. The latter could explain the reported DNA oxidative damage found in vivo following methylaminoazobenzene administration [Hirano et al. Analyses of Oxidative DNA Damage and Its Repair Activity in the Livers of 3'-Methyl-4-dimethylaminoazobenzene-Treated Rodents. Jpn. J. Cancer Res. 2000, 91, 681-685]. It was also found that the prooxidant activity of the aromatic amine increased as its redox potential, i.e., ease of oxidation decreased with o-anisidine and aminofluorene being the most effective at forming reactive oxygen species. This suggests that the rate-limiting step in the cooxidation is the rate of arylamine oxidation by the peroxidase. Incubation of hepatocytes with aromatic amines caused a decrease in the mitochondrial membrane potential before cytotoxicity ensued. The CYP1A2-induced hepatocytes isolated from 3-methylcholanthrene administered rats were much more susceptible to some arylamines and were protected by CYP1A2 inhibitors. Hepatocyte GSH was also depleted by all arylamines tested and extensive GSH oxidation occurred with o-anisidine and aminofluorene, which was prevented by CYP1A2 inhibitors. This suggests that in intact hepatocytes CYP1A2 may also catalyze a one-electron oxidation of some arylamines to form prooxidant cation radicals, which cooxidize GSH to form the reactive oxygen species.
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Affiliation(s)
- Arno G Siraki
- Faculty of Pharmacy, University of Toronto, Ont, Canada
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36
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Schabath MB, Spitz MR, Hong WK, Delclos GL, Reynolds WF, Gunn GB, Whitehead LW, Wu X. A myeloperoxidase polymorphism associated with reduced risk of lung cancer. Lung Cancer 2002; 37:35-40. [PMID: 12057865 DOI: 10.1016/s0169-5002(02)00034-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Myeloperoxidase (MPO) is a metabolic/oxidative enzyme found in neutrophils and monocytes that contributes to pulmonary carcinogenesis through activation of specific procarcinogens including benzo[a]pyrene intermediates, 4-aminobiphenyl and the arylamines. There is a G-->A polymorphism located in the 5' untranslated region of the MPO gene that may be responsible for reduced transcriptional activity due to the decreased binding affinity for the SP1 transcription factor. Individuals with one or two copies of the A-allele may be afforded protection due to decreased transcriptional activity of MPO and subsequent decreased metabolic activation of procarcinogens. Previous studies have reported a range of protective effects in different ethnic populations. We employed a restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) assay to identify the MPO genotypes in 375 lung cancer cases and 378 healthy controls, all of whom were Caucasian. Our results demonstrate a reduced risk of lung cancer when the A-allele genotypes (G/A+A/A) were combined (odds ratio (OR)=0.66; 95% confidence interval (CI) 0.49-0.90). We also noted a protective effect (OR=0.63; 95% CI 0.45-0.87) in ever smokers with the A-allele genotypes which was not evident in never smokers (OR=1.14; 95% CI 0.42-3.11). We observed an incremental decrease in the protective effects as cigarette pack-years increased. Thus, lightest smokers were provided the greatest protection. When the data were stratified by gender, there was a statistically significant reduced risk of lung cancer among men (OR=0.55; 95% CI 0.36-0.84), but not among women (OR=0.81; 95% CI 0.55-1.26) for the A-allele genotypes. Lastly, an age effect was evident only in men but not women. The protective effects of the A-allele genotypes decreased with increasing age. This report provides further support for the hypothesis that a single nucleotide polymorphism in the MPO gene is a protective factor in lung cancer carcinogenesis.
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Affiliation(s)
- Matthew B Schabath
- Department of Epidemiology, The University of Texas M.D. Anderson Cancer Center, Box 189, 1515 Holcombe Blvd, Houston, TX 77030, USA
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37
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Abstract
Arylamine N-acetyltransferases (NATs) play an important role in the interaction of competing metabolic pathways determining the fate of and response to xenobiotics as therapeutic drugs, occupational chemicals and carcinogenic substances. Individual susceptibility for drug response and possible adverse drug reactions are modulated by the genetic predisposition (manifested for example, by polymorphisms) and the phenotype of these enzymes. For all drugs metabolized by NATs, the impact of different in vivo enzyme activities is reviewed with regard to therapeutic use, prevention of side effects and possible indications for risk assessment by phenotyping and/or genotyping. As genes of NATs are susceptibility genes for multifactorial adverse effects and xenobiotic-related diseases, risk prediction can only be made possible by taking the complexity of events into consideration.
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Affiliation(s)
- Peter Meisel
- Department of Pharmacology, Ernst Moritz Arndt University Greifswald, F-Loeffler-Str. 23d, D-17487 Greifswald, Germany.
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Kawanishi S, Hiraku Y, Murata M, Oikawa S. The role of metals in site-specific DNA damage with reference to carcinogenesis. Free Radic Biol Med 2002; 32:822-32. [PMID: 11978484 DOI: 10.1016/s0891-5849(02)00779-7] [Citation(s) in RCA: 193] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We reviewed the mechanism of oxidative DNA damage with reference to metal carcinogenesis and metal-mediated chemical carcinogenesis. On the basis of the finding that chromium (VI) induced oxidative DNA damage in the presence of hydrogen peroxide (H2O2), we proposed the hypothesis that endogenous reactive oxygen species play a role in metal carcinogenesis. Since then, we have reported that various metal compounds, such as cobalt, nickel, and ferric nitrilotriacetate, directly cause site-specific DNA damage in the presence of H2O2. We also found that carcinogenic metals could cause DNA damage through indirect mechanisms. Certain nickel compounds induced oxidative DNA damage in rat lungs through inflammation. Endogenous metals, copper and iron, catalyzed ROS generation from various organic carcinogens, resulting in oxidative DNA damage. Polynuclear compounds, such as 4-aminobiphenyl and heterocyclic amines, appear to induce cancer mainly through DNA adduct formation, although their N-hydroxy and nitroso metabolites can also cause oxidative DNA damage. On the other hand, mononuclear compounds, such as benzene metabolites, caffeic acid, and o-toluidine, should express their carcionogenicity through oxidative DNA damage. Metabolites of certain carcinogens efficiently caused oxidative DNA damage by forming NADH-dependent redox cycles. These findings suggest that metal-mediated oxidative DNA damage plays important roles in chemical carcinogenesis.
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Affiliation(s)
- Shosuke Kawanishi
- Department of Hygiene, Mie University School of Medicine, Edobashi, Tsu, Japan.
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39
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Coles BF, Morel F, Rauch C, Huber WW, Yang M, Teitel CH, Green B, Lang NP, Kadlubar FF. Effect of polymorphism in the human glutathione S-transferase A1 promoter on hepatic GSTA1 and GSTA2 expression. PHARMACOGENETICS 2001; 11:663-9. [PMID: 11692074 DOI: 10.1097/00008571-200111000-00004] [Citation(s) in RCA: 172] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The patterns of expression of glutathione S-transferases A1 and A2 in human liver (hGSTA1 and hGSTA2, respectively) are highly variable, notably in the ratio of hGSTA1/hGSTA2. We investigated if this variation had a genetic basis by sequencing the proximal promoters (-721 to -1 nucleotides) of hGSTA1 and hGSTA2, using 55 samples of human liver that exemplified the variability of hGSTA1 and hGSTA2 expression. Variants were found in the hGSTA1 gene: -631T or G, -567T, -69C, -52G, designated as hGSTA1*A; and -631G, -567G, -69T, -52A, designated as hGSTA1*B. Genotyping for the substitution -69C > T by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP), showed that the polymorphism was widespread in Caucasians, African-Americans and Hispanics, and that it appeared to conform to allelic variation. Constructs consisting of the proximal promoters of hGSTA1*A, hGSTA1*B or hGSTA2, with luciferase as a reporter gene, showed differential expression when transfected into HepG2 cells: hGSTA1*A approximately hGSTA2 > hGSTA1*B. Similarly, mean levels of hGSTA1 protein expression in liver cytosols decreased significantly according to genotype: hGSTA1*A > hGSTA1-heterozygous > hGSTA1*B. Conversely, mean hGSTA2 expression increased according to the same order of hGSTA1 genotype. Consequently, the ratio of GSTA1/GSTA2 was highly hGSTA1 allele-specific. Because the polymorphism in hGSTA1 correlates with hGSTA1 and hGSTA2 expression in liver, and hGSTA1-1 and hGSTA2-2 exhibit differential catalysis of the detoxification of carcinogen metabolites and chemotherapeutics, the polymorphism is expected to be of significance for individual risk of cancer or individual response to chemotherapeutic agents.
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Affiliation(s)
- B F Coles
- Division of Molecular Epidemiology, National Center for Toxicological Research, Jefferson, Arkansas 72079-9502, USA.
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40
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Misra RR, Tangrea JA, Virtamo J, Ratnasinghe D, Andersen MR, Barrett M, Taylor PR, Albanes D. Variation in the promoter region of the myeloperoxidase gene is not directly related to lung cancer risk among male smokers in Finland. Cancer Lett 2001; 164:161-7. [PMID: 11179831 DOI: 10.1016/s0304-3835(01)00384-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In order to examine whether a polymorphism in the promoter region of the myeloperoxidase (MPO) gene is associated with lung cancer among male smokers, we conducted a case-control study nested within a Finnish clinical trial cohort. Although we found no evidence of an overall association between lung cancer risk and MPO genotype, the variant MPO genotype was associated with an increased risk of lung cancer among a subset of older men. These findings contrast with those from previous studies that report decreased lung cancer risk among MPO variant individuals.
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Affiliation(s)
- R R Misra
- Cancer Prevention Studies Branch, Division of Clinical Sciences, National Cancer Institute, 6006 Executive Boulevard, Suite 321, Bethesda, MD 20892-7058, USA.
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41
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Tang YM, Green BL, Chen GF, Thompson PA, Lang NP, Shinde A, Lin DX, Tan W, Lyn-Cook BD, Hammons GJ, Kadlubar FF. Human CYP1B1 Leu432Val gene polymorphism: ethnic distribution in African-Americans, Caucasians and Chinese; oestradiol hydroxylase activity; and distribution in prostate cancer cases and controls. PHARMACOGENETICS 2000; 10:761-6. [PMID: 11221602 DOI: 10.1097/00008571-200012000-00001] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Cytochrome P4501B1 (CYP1B1) is involved in the activation of many carcinogens and in the metabolism of steroid hormones, including 17beta-oestradiol (E2) and testosterone. We report a significant difference in the allele frequencies of two point mutations in the coding region of the CYP1B1 gene among Caucasian (n = 189), African-American (n = 52) and Chinese (Linxian) (n = 109) populations. A (C to G) transversion at position 1666 in exon 3, which results in an amino acid substitution of Leu432 to Val, was present in African-Americans with an allele frequency for Va1432 of 0.75, in Caucasians of 0.43, and in Chinese of 0.17. A (C to T) transition at position 1719 in exon 3, with no amino acid change (Asp449), appeared to be closely linked with the Val432 variant. Results using human lung microsomal preparations from individuals with the CYP1B1Val/Val and CYP1B1Leu/Leu genotypes indicate that Val432 variant may be a high activity allele and thus may contribute to the interindividual differences in CYP1B1 activity. Because CYP1B1 is involved in hormone and carcinogen metabolism, and given the disparate rates of prostate cancer among ethnic groups, we also evaluated the association of the CYP1B1 Leu432Val polymorphism with prostate cancer risk in a pilot case-control study. Among Caucasians, 34% of men with cancer (n = 50) were homozygous for the Val432 polymorphism, while only 12% of matched control subjects (n = 50) had this genotype. These preliminary data indicate that genetic polymorphisms in CYP1B1 might play an important role in human prostate carcinogenesis.
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Affiliation(s)
- Y M Tang
- Division of Molecular Epidemiology, National Center for Toxicological Research, Jefferson, AR 72079, USA
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Pak JW, Knoke KL, Noguera DR, Fox BG, Chambliss GH. Transformation of 2,4,6-trinitrotoluene by purified xenobiotic reductase B from Pseudomonas fluorescens I-C. Appl Environ Microbiol 2000; 66:4742-50. [PMID: 11055918 PMCID: PMC92374 DOI: 10.1128/aem.66.11.4742-4750.2000] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The enzymatic transformation of 2,4,6-trinitrotoluene (TNT) by purified XenB, an NADPH-dependent flavoprotein oxidoreductase from Pseudomonas fluorescens I-C, was evaluated by using natural abundance and [U-(14)C]TNT preparations. XenB catalyzed the reduction of TNT either by hydride addition to the aromatic ring or by nitro group reduction, with the accumulation of various tautomers of the protonated dihydride-Meisenheimer complex of TNT, 2-hydroxylamino-4,6-dinitrotoluene, and 4-hydroxylamino-2, 6-dinitrotoluene. Subsequent reactions of these metabolites were nonenzymatic and resulted in predominant formation of at least three dimers with an anionic m/z of 376 as determined by negative-mode electrospray ionization mass spectrometry and the release of approximately 0.5 mol of nitrite per mol of TNT consumed. The extents of the initial enzymatic reactions were similar in the presence and in the absence of O(2), but the dimerization reaction and the release of nitrite were favored under aerobic conditions or under anaerobic conditions in the presence of NADP(+). Reactions of chemically and enzymatically synthesized and high-pressure liquid chromatography-purified TNT metabolites showed that both a hydroxylamino-dinitrotoluene isomer and a tautomer of the protonated dihydride-Meisenheimer complex of TNT were required precursors for the dimerization and nitrite release reactions. The m/z 376 dimers also reacted with either dansyl chloride or N-1-naphthylethylenediamine HCl, providing evidence for an aryl amine functional group. In combination, the experimental results are consistent with assigning the chemical structures of the m/z 376 species to various isomers of amino-dimethyl-tetranitrobiphenyl. A mechanism for the formation of these proposed TNT metabolites is presented, and the potential enzymatic and environmental significance of their formation is discussed.
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Affiliation(s)
- J W Pak
- Department of Bacteriology, University of Wisconsin, Madison, Wisconsin 53706, USA
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43
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Coles B, Yang M, Lang NP, Kadlubar FF. Expression of hGSTP1 alleles in human lung and catalytic activity of the native protein variants towards 1-chloro-2,4-dinitrobenzene, 4-vinylpyridine and (+)-anti benzo[a]pyrene-7,8-diol-9,10-oxide. Cancer Lett 2000; 156:167-75. [PMID: 10880766 DOI: 10.1016/s0304-3835(00)00458-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The human glutathione S-transferase (GST) P1 alleles coding for Val(105) (hGSTP1*B and/or P1*C) are over- represented in lung cancer patients. However, the corresponding recombinant Val(105) protein variants tend to show higher catalytic activity than the Ile(105) variants towards bay-region diol epoxides that are thought to be etiological agents in lung cancer. We have examined 29 normal human lung samples with respect to several factors that could confound relationships between hGSTP1 allele type and cancer susceptibility, namely, inter-individual and allele-specific variation of hGSTP1 expression, and differences between the catalytic properties of the native and recombinant hGSTP1-1 variant protein products. hGSTP1 expression varied 7-fold among individuals but was independent of hGSTP1*A, P1*B or P1*C allele type. hGST subunits A1, A2, M1 and M3 were minor components, similarly variable in expression. Despite this variability of expression, the levels of hGSTP1 expression linearly correlated with those of the next most highly expressed GST, hGSTM3, even though the genes for these GSTs are on different chromosomes. Differences between the native protein variants, using 1-chloro-2,4-dinitrobenzene and (+)-anti-benzo[a]pyrene diolepoxide as substrates, were more marked than those between the recombinant variants. However, the order of differential catalytic specificity was the same for native and recombinant variants. Neither the expression of the hGSTP1 alleles nor the catalytic properties of the protein variants appears to provide a simple mechanistic rationale for the observed over-representation of the hGSTP1*B and/or 1*C alleles in lung cancer.
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Affiliation(s)
- B Coles
- Division of Molecular Epidemiology, National Center for Toxicological Research, 3900 NCTR Rd., Jefferson, AR 72079, USA.
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King RS, Teitel CH, Kadlubar FF. In vitro bioactivation of N -hydroxy-2-amino-α-carboline. Carcinogenesis 2000. [DOI: 10.1093/carcin/21.7.1347] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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King RS, Teitel CH, Kadlubar FF. In vitro bioactivation of N-hydroxy-2-amino-α-carboline. Carcinogenesis 2000. [DOI: 10.1093/carcin/21.5.347] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Ohkuma Y, Hiraku Y, Oikawa S, Yamashita N, Murata M, Kawanishi S. Distinct mechanisms of oxidative DNA damage by two metabolites of carcinogenic o-toluidine. Arch Biochem Biophys 1999; 372:97-106. [PMID: 10562421 DOI: 10.1006/abbi.1999.1461] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mechanisms of DNA damage by metabolites of carcinogenic o-toluidine in the presence of metals were investigated by the DNA sequencing technique using (32)P-labeled human DNA fragments. 4-Amino-3-methylphenol, a major metabolite, caused DNA damage in the presence of Cu(II). Predominant cleavage sites were thymine and cytosine residues. o-Nitrosotoluene, a minor metabolite, did not induce DNA damage even in the presence of Cu(II), but addition of NADH induced DNA damage very efficiently. The DNA cleavage pattern was similar to that in the case of 4-amino-3-methylphenol. Bathocuproine and catalase inhibited DNA damage by these o-toluidine metabolites, indicating the participation of Cu(I) and H(2)O(2) in the DNA damage. Typical free hydroxyl radical scavengers showed no inhibitory effects on the DNA damage. o-Toluidine metabolites increased the formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine in calf thymus DNA in the presence of Cu(II). UV-visible and ESR spectroscopic studies have demonstrated that 4-amino-3-methylphenol is autoxidized to form the aminomethylphenoxyl radical and o-nitrosotoluene is reduced by NADH to the o-toluolhydronitroxide radical in the presence and absence of Cu(II). Consequently, it is considered that these radicals react with O(2) to form O(-)(2) and subsequently H(2)O(2), and that the reactive species generated by the reaction of H(2)O(2) with Cu(I) participate in the DNA damage. Metal-mediated DNA damage by o-toluidine metabolites through H(2)O(2) seems to be relevant for the expression of the carcinogenicity of o-toluidine.
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Affiliation(s)
- Y Ohkuma
- Department of Hygiene, Mie University School of Medicine, 2-174 Edobashi, Mie, 514-8507, Japan
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Abstract
For many years (32)P postlabeling has detected DNA adducts at very low levels and yet has not been able to identify unknown adducts. Mass spectrometry offers substantially improved identification powers, albeit at some loss in detection limits. With this ultimate utilization of mass spectrometry in mind, the current research presents a new method to quantitatively purify bulky hydrophobic DNA adducts at levels that are pertinent to ongoing DNA adduct research in human health and environmental fields. This method was demonstrated with benzo[a]pyrene adducts. Purification was accomplished with the use of small columns (7.5-mm frits) with an 11 mg bed of polystyrene-divinlybenzene beads which retained the adducts while permitting the nonadducted nucleotides to be washed out with water. Subsequently, the adducts were eluted with 50% MeOH and the sample was reduced in volume in an evacuated centrifuge. Purification was demonstrated at adduct levels ranging from 4 adducts in 10(6) nonadducted nucleotides to 4 in 10(8). For these levels, analyses by capillary electrophoresis with sample stacking and UV detection determined that recoveries ranged from 91 to 54%, respectively. The adduct quantities isolated should be sufficient to allow the use of current MS capabilities that are linked on-line to separation methodologies such as capillary electrophoresis, capillary electrochromatography, and high-pressure liquid chromatography.
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Affiliation(s)
- C B Norwood
- U. S. EPA AED, 27 Tarzwell Drive, Narragansett, Rhode Island 02882, USA
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Aromatic Amines, Nitroarenes, and Heterocyclic Aromatic Amines. Toxicology 1999. [DOI: 10.1016/b978-012473270-4/50089-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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49
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Abstract
The 32P-postlabelling assay is widely used for detection of carcinogen-DNA adducts and other types of modified nucleotides in DNA. The principle of the method is the enzymatic digestion of DNA to nucleotides, 5'-labelling of these nucleotides with an isotopically labelled phosphate group, and the resolution and detection of the labelled products. Since the development of the original procedure in the early 1980s, many methods have been developed to increase the sensitivity of the method by selection of the modified nucleotides prior to labelling. In favourable circumstances, the method can achieve a level of detection as low as 1 modification in 10(10) nucleotides and requires relatively small quantities of DNA (less than 10 microg). It has been used to detect and characterise DNA adducts formed by numerous genotoxic carcinogens in bacterial and mammalian cells, in animals and, in some cases, in human tissues. Most classes of carcinogen have been subjected to 32P-postlabelling analysis, ranging from bulky and/or aromatic compounds to small and/or aliphatic compounds; it has also been used, with modifications, to detect apurinic sites in DNA, oxidative damage to DNA, UV-induced photodimers and, to a lesser extent, DNA damage caused by cytotoxic drugs. It has provided the first clear evidence for the DNA-damaging properties of several synthetic carcinogenic hormones. It has revealed the DNA-damaging potential of complex mixtures such as coal-tar and tobacco smoke. It has been used in human biomonitoring studies to detect DNA damage from occupational exposure to carcinogens, and also from environmental (i.e. non-occupational) exposures. It has also led to the discovery of the presence of numerous modifications in DNA arising from endogenous processes. The rapid expansion in the use of the assay has resulted in some divergence of procedures and there is a case to be made for the use of more standardised protocols, particularly where human exposure to carcinogens is being measured and where such results may be required for risk assessment. While the procedure is quantifiable, the efficiency of adduct labelling is, in many cases, not quantitative, and the lack of adduct standards has, in many cases, limited the interpretation of data to a demonstration of higher adduct levels in exposed groups compared with unexposed groups. Future developments are expected in automation, standardisation and, in combination with other analytical methods, elucidation of the structures of the many DNA lesions whose existence has been revealed by the 32P-postlabelling technique.
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Affiliation(s)
- D H Phillips
- Haddow Laboratories, Institute of Cancer Research, Sutton, UK
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