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Dong S, Yang H, Ye D. Development of an LC-MS Method for 4-Fluoroaniline Determination in Ezetimibe. J Chromatogr Sci 2018; 56:724-730. [PMID: 29762651 DOI: 10.1093/chromsci/bmy048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 04/26/2018] [Indexed: 11/13/2022]
Abstract
A rapid and sensitive high-performance liquid chromatography-mass spectrometry method was developed and validated to determine 4-fluoroaniline concentration in ezetimibe. Chromatographic separation was achieved on a Phenomenex Gemini-NX C18 column (150 × 4.6 mm, 3 μm) maintained at 30°C. The liquid chromatography system was operated in gradient mode with an injection volume of 20 μL at a flow rate of 1 mL/min. Mobile phase A was water and mobile phase B consisted of acetonitrile with 0.05% acetic acid. The detection was performed using a single quadrupole mass spectrometer in single ion monitoring mode by using positive ionization. An m/z value of 112 was selected for monitoring 4-fluoroaniline. The method showed good linearity over the concentration range of 0.94-30.26 ng/mL. The limit of quantification and limit of detection were 0.19 and 0.94 ng/mL, respectively. The precision relative standard deviations were less than 8.7% (n = 12), and the accuracy values were within 92-99%. A standard solution of 4-fluoroaniline was stable for at least 24 h at 25°C. Small changes in the organic phase acidity of the mobile phase, flow rate, column temperature, and the instrument parameters had no significant effect on the results for 4-fluoroaniline.
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Affiliation(s)
- Shubo Dong
- School of Chemistry and Chemical Engineering, Nanjing University, Xianlin Road No. 163, Nanjing, Jiangsu, China.,Jiangsu Deyuan Pharm. Co., Ltd. Jinqiao Road No. 21, Lianyungang, Jiangsu, China
| | - Hanyue Yang
- Jiangsu Deyuan Pharm. Co., Ltd. Jinqiao Road No. 21, Lianyungang, Jiangsu, China
| | - Deju Ye
- School of Chemistry and Chemical Engineering, Nanjing University, Xianlin Road No. 163, Nanjing, Jiangsu, China
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2
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Kung RW, Sharma P, Wetmore SD. Effect of Size and Shape of Nitrogen-Containing Aromatics on Conformational Preferences of DNA Containing Damaged Guanine. J Chem Inf Model 2018; 58:1415-1425. [PMID: 29923712 DOI: 10.1021/acs.jcim.8b00238] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Ryan W. Kung
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, Canada T1K 3M4
| | - Purshotam Sharma
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, Canada T1K 3M4
| | - Stacey D. Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, Canada T1K 3M4
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Tomioka K, Saeki K, Obayashi K, Tanaka Y, Kurumatani N. Risk for lung cancer in workers exposed to benzidine and/or beta-naphthylamine: a protocol for systematic review and meta-analysis. Syst Rev 2014; 3:112. [PMID: 25281283 PMCID: PMC4186647 DOI: 10.1186/2046-4053-3-112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 09/24/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Risk for lung cancer in workers exposed to benzidine (BZ) and/or beta-naphthylamine (BNA), which are well-known bladder carcinogens, has been examined in many epidemiological studies, but individual epidemiological studies generally lack the power to examine the association between BZ/BNA exposure and lung cancer. We conduct a systematic review and meta-analysis to determine the risk for lung cancer among workers exposed to BZ/BNA occupationally. METHODS/DESIGN Studies will be identified by a MEDLINE, EMBASE, CDSR, and CINAHL search and by the reference lists of articles/relevant reviews. Eligible studies will be cohort and case-control studies that report occupational BZ/BNA exposure and the outcome of interest (lung cancer death/incidence). The method of meta-analysis will be used to combine standardized mortality ratios (SMRs) and/or standardized incidence ratios (SIRs) from retrospective and prospective cohort studies and odds ratios (ORs) from case-control studies. Two reviewers will independently screen articles, extract data, and assess scientific quality using standardized forms and published quality assessment tools tailored for each study design. Overall pooled risk estimates and their corresponding 95% confidence intervals (CIs) will be obtained using random effects model. This systematic review and meta-analysis will be conducted following the Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines, and results will be reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. DISCUSSION This review will identify and synthesize studies of the association between occupational BZ/BNA exposure and lung cancer. The findings will help to identify whether BZ/BNA could cause lung cancer and might indicate whether workers with exposure to BZ/BNA have a need for preventive measures against non-urological cancer besides bladder cancer. SYSTEMATIC REVIEW REGISTRATION PROSPERO CRD42014010250.
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Affiliation(s)
- Kimiko Tomioka
- Department of Community Health and Epidemiology, Nara Medical University, Shijo-cho 840, Kashihara City, Nara 634-8521, Japan
| | - Keigo Saeki
- Department of Community Health and Epidemiology, Nara Medical University, Shijo-cho 840, Kashihara City, Nara 634-8521, Japan
| | - Kenji Obayashi
- Department of Community Health and Epidemiology, Nara Medical University, Shijo-cho 840, Kashihara City, Nara 634-8521, Japan
| | - Yuu Tanaka
- Department of Anesthesiology, Nara Medical University, Shijo-cho 840, Kashihara City, Nara, Japan
| | - Norio Kurumatani
- Department of Community Health and Epidemiology, Nara Medical University, Shijo-cho 840, Kashihara City, Nara 634-8521, Japan
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Tomioka K, Obayashi K, Saeki K, Okamoto N, Kurumatani N. Increased risk of lung cancer associated with occupational exposure to benzidine and/or beta-naphthylamine. Int Arch Occup Environ Health 2014; 88:455-65. [PMID: 25151432 DOI: 10.1007/s00420-014-0974-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 08/12/2014] [Indexed: 11/28/2022]
Abstract
PURPOSE To evaluate non-urological cancer risks associated with benzidine (BZ) and beta-naphthylamine (BNA), a historical cohort study was undertaken. METHODS A total of 224 male workers exposed to BZ/BNA from a single factory were followed from 1953 to 2011. To estimate BZ/BNA exposure dose, duration of exposure (DOE) was defined as duration of employment between 1953 and 1972, the period when BZ and BNA were produced and used at this factory. Subjects were dichotomized (into long- and short-term groups) based on the median of DOE. Cancer-specific standardized incidence ratios (SIRs) were calculated using national and regional incidence rates as reference. Smoking history was obtained through questionnaires and other sources. Association between lung cancer (LC) or bladder cancer (BC) incidence and DOE was assessed using Cox's proportional hazards model. RESULTS Vital status follow-up was successful for 216 (96.4%). Follow-up duration averaged 44.0 (SD 10.7) years. Increased SIRs based on national rates were found for all cancers (81 cases, SIR = 1.58, 95% CI 1.26-1.98), LC (18 cases, SIR = 2.58, 95% CI 1.53-4.07), and BC (7 cases, SIR = 4.70, 95% CI 1.89-9.67). Among workers with >20 years after first exposure, the SIR for LC was statistically elevated in the long DOE group (15 cases, SIR = 3.34, 95% CI 1.87-5.51). After adjustment for smoking, exposure to bis(chloromethyl) ether, and age at first exposure, a marginally significant hazard ratio (HR) was observed for the long DOE group (adjusted HR = 3.02, 95% CI 0.84-10.93, p = 0.091), compared to the short DOE group. DOE did not affect BC incidence. CONCLUSIONS This study confirms the high risk of LC besides BC, suggesting that BZ/BNA have the potential to cause LC.
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Affiliation(s)
- Kimiko Tomioka
- Department of Community Health and Epidemiology, Nara Medical University, Shijo-cho 840, Kashihara City, Nara, zip code 6348521, Japan,
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Mohammed M, Ch S, Ch RV. Aniline is an inducer, and not a precursor, for indole derivatives in Rubrivivax benzoatilyticus JA2. PLoS One 2014; 9:e87503. [PMID: 24533057 PMCID: PMC3922755 DOI: 10.1371/journal.pone.0087503] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 12/27/2013] [Indexed: 11/19/2022] Open
Abstract
Rubrivivax benzoatilyticus JA2 and other anoxygenic photosynthetic bacteria produce indole derivatives when exposed to aniline, a xenobiotic compound. Though this phenomenon has been reported previously, the role of aniline in the production of indoles is still a biochemical riddle. The present study aims at understanding the specific role of aniline (as precursor or stimulator) in the production of indoles and elucidating the biochemical pathway of indoles in aniline-exposed cells by using stable isotope approaches. Metabolic profiling revealed tryptophan accumulation only in aniline exposed cells along with indole 3-acetic acid (IAA) and indole 3-aldehyde (IAld), the two major catabolites of tryptophan. Deuterium labelled aniline feeding studies revealed that aniline is not a precursor of indoles in strain JA2. Further, production of indoles only in aniline-exposed cells suggests that aniline is an indoles stimulator. In addition, production of indoles depended on the presence of a carbon source, and production enhanced when carbon sources were added to the culture. Isotope labelled fumarate feeding identified, fumarate as the precursor of indole, indicating de novo synthesis of indoles. Glyphosate (shikimate pathway inhibitor) inhibited the indoles production, accumulation of tryptophan, IAA and IAld indicating that indoles synthesis in strain JA2 occurs via the de novo shikimate pathway. The up-regulation of anthranilate synthase gene and induction of anthranilate synthase activity correlated well with tryptophan production in strain JA2. Induction of tryptophan aminotransferase and tryptophan 2-monooxygenase activities corroborated well with IAA levels, suggesting that tryptophan catabolism occurs simultaneously in aniline exposed cells. Our study demonstrates that aniline (stress) stimulates tryptophan/indoles synthesis via the shikimate pathway by possibly modulating the metabolic pathway.
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Affiliation(s)
- Mujahid Mohammed
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Sasikala Ch
- Bacterial Discovery Laboratory, Centre for Environment, IST, J NT University Hyderabad, Kukatpally, Hyderabad, India
| | - Ramana V. Ch
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, India
- * E-mail:
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Powell JB, Ghotbaddini M. Cancer-promoting and Inhibiting Effects of Dietary Compounds: Role of the Aryl Hydrocarbon Receptor (AhR). ACTA ACUST UNITED AC 2014; 3. [PMID: 25258701 PMCID: PMC4172379 DOI: 10.4172/2167-0501.1000131] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Polyaromatic hydrocarbons, heterocyclic aromatic amines and dioxin-like compounds are environmental carcinogens shown to initiate cancer in a number of tissue types including prostate and breast. These environmental carcinogens elicit their effects through interacting with the aryl hydrocarbon receptor (AhR), a ligand activated transcription factor. Naturally occurring compounds found in fruits and vegetables shown to have anti-carcinogenic effects also interact with the AhR. This review explores dietary and environmental exposure to chemical carcinogens and beneficial natural compounds whose effects are elicited by the AhR.
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Affiliation(s)
- Joann B Powell
- Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, GA USA
| | - Maryam Ghotbaddini
- Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, GA USA
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Shamovsky I, Ripa L, Blomberg N, Eriksson LA, Hansen P, Mee C, Tyrchan C, O'Donovan M, Sjö P. Theoretical Studies of Chemical Reactivity of Metabolically Activated Forms of Aromatic Amines toward DNA. Chem Res Toxicol 2012; 25:2236-52. [DOI: 10.1021/tx300313b] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Igor Shamovsky
- Department of Medicinal Chemistry, R&I iMed, AstraZeneca R&D, Pepparedsleden 1, S-431 83 Mölndal, Sweden
| | - Lena Ripa
- Department of Medicinal Chemistry, R&I iMed, AstraZeneca R&D, Pepparedsleden 1, S-431 83 Mölndal, Sweden
| | - Niklas Blomberg
- Department of Medicinal Chemistry, R&I iMed, AstraZeneca R&D, Pepparedsleden 1, S-431 83 Mölndal, Sweden
| | - Leif A. Eriksson
- Department of Chemistry and Molecular Biology, University of Gothenburg, S-412 96 Göteborg, Sweden
| | - Peter Hansen
- Department of Medicinal Chemistry, R&I iMed, AstraZeneca R&D, Pepparedsleden 1, S-431 83 Mölndal, Sweden
| | - Christine Mee
- Genetic Toxicology, AstraZeneca R&D, Alderley Park, Macclesfield, Cheshire, SK10 4TG, United Kingdom
| | - Christian Tyrchan
- Department of Medicinal Chemistry, CVGI iMed, AstraZeneca R&D, Pepparedsleden 1, S-431 83 Mölndal, Sweden
| | - Mike O'Donovan
- Genetic Toxicology, AstraZeneca R&D, Alderley Park, Macclesfield, Cheshire, SK10 4TG, United Kingdom
| | - Peter Sjö
- Department of Medicinal Chemistry, R&I iMed, AstraZeneca R&D, Pepparedsleden 1, S-431 83 Mölndal, Sweden
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Liu S, Wang W, Chen J, Sun J. Determination of aniline and its derivatives in environmental water by capillary electrophoresis with on-line concentration. Int J Mol Sci 2012; 13:6863-6872. [PMID: 22837668 PMCID: PMC3397500 DOI: 10.3390/ijms13066863] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 04/27/2012] [Accepted: 05/17/2012] [Indexed: 11/23/2022] Open
Abstract
This paper describes a simple, sensitive and environmentally benign method for the direct determination of aniline and its derivatives in environmental water samples by capillary zone electrophoresis (CZE) with field-enhanced sample injection. The parameters that influenced the enhancement and separation efficiencies were investigated. Surprisingly, under the optimized conditions, two linear ranges for the calibration plot, 1–50 ng/mL and 50–1000 ng/mL (R > 0.998), were obtained. The detection limit was in the range of 0.29–0.43 ng/mL. To eliminate the effect of the real sample matrix on the stacking efficiency, the standard addition method was applied to the analysis of water samples from local rivers.
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Affiliation(s)
- Shuhui Liu
- College of Sciences, Northwest A & F University, Yangling, Shaanxi 712100, China; E-Mails: (W.W.); (J.C.); (J.S.)
- State Key Laboratory of Crop Stress Biology in Arid Areas, Yangling 712100, China
- Author to whom correspondence should be addressed; E-Mail: ; Tel./Fax: +86-029-8709-2226
| | - Wenjun Wang
- College of Sciences, Northwest A & F University, Yangling, Shaanxi 712100, China; E-Mails: (W.W.); (J.C.); (J.S.)
| | - Jie Chen
- College of Sciences, Northwest A & F University, Yangling, Shaanxi 712100, China; E-Mails: (W.W.); (J.C.); (J.S.)
| | - Jianzhi Sun
- College of Sciences, Northwest A & F University, Yangling, Shaanxi 712100, China; E-Mails: (W.W.); (J.C.); (J.S.)
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Turesky RJ, Bessette EE, Dunbar D, Liberman RG, Skipper PL. Cytochrome P450-mediated metabolism and DNA binding of 2-amino-1,7-dimethylimidazo[4,5-g]quinoxaline and its carcinogenic isomer 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline in mice. Chem Res Toxicol 2012; 25:410-21. [PMID: 22118226 PMCID: PMC3531872 DOI: 10.1021/tx2004536] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
2-Amino-1,7-dimethylimidazo[4,5-g]quinoxaline (MeIgQx) is a recently discovered heterocyclic aromatic amine (HAA) that is formed during the cooking of meats. MeIgQx is an isomer of 2-amino-3,8-dimethylmidazo[4,5-f]quinoxaline (MeIQx), a rodent carcinogen and possible human carcinogen that also occurs in cooked meats. MeIgQx is a bacterial mutagen, but knowledge about its metabolism and carcinogenic potential is lacking. Metabolism studies on MeIgQx and MeIQx were conducted with human and mouse liver microsomes, and recombinant human P450s. DNA binding studies were also investigated in mice to ascertain the genotoxic potential of MeIgQx in comparison to MeIQx. Both HAAs underwent comparable rates of N-oxidation to form genotoxic N-hydroxylated metabolites with mouse liver microsomes (0.2-0.3 nmol/min/mg protein). The rate of N-oxidation of MeIQx was 4-fold greater than the rate of N-oxidation of MeIgQx with human liver microsomes (1.7 vs 0.4 nmol/min/mg protein). The rate of N-oxidation, by recombinant human P450 1A2, was comparable for both substrates (6 pmol/min/pmol P450 1A2). MeIgQx also underwent N-oxidation by human P450s 1A1 and 1B1 at appreciable rates, whereas MeIQx was poorly metabolized by these P450s. The potential of MeIgQx and MeIQx to form DNA adducts was assessed in female C57BL/6 mice given [(14)C]-MeIgQx (10 μCi, 9.68 mg/kg body wt) or [(14)C]-MeIQx (10 μCi, 2.13 mg/kg body wt). DNA adduct formation in the liver, pancreas, and colorectum was measured by accelerator mass spectrometry at 4, 24, or 48 h post-treatment. Variable levels of adducts were detected in all organs. The adduct levels were similar for both HAAs, when adjusted for dose, and ranged from 1 to 600 adducts per 10(7) nucleotides per mg/kg dose. Thus, MeIgQx undergoes metabolic activation and binds to DNA at levels that are comparable to MeIQx. Given the high amounts of MeIgQx formed in cooked meats, further investigations are warranted to assess the carcinogenic potential of this HAA.
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Affiliation(s)
- Robert J Turesky
- Division of Environmental Health Sciences, Wadsworth Center, New York State Department of Health , Albany, New York 12201, United States.
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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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Kirkland D, Reeve L, Gatehouse D, Vanparys P. A core in vitro genotoxicity battery comprising the Ames test plus the in vitro micronucleus test is sufficient to detect rodent carcinogens and in vivo genotoxins. Mutat Res 2011; 721:27-73. [PMID: 21238603 DOI: 10.1016/j.mrgentox.2010.12.015] [Citation(s) in RCA: 161] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 11/12/2010] [Accepted: 12/15/2010] [Indexed: 01/27/2023]
Abstract
In vitro genotoxicity testing needs to include tests in both bacterial and mammalian cells, and be able to detect gene mutations, chromosomal damage and aneuploidy. This may be achieved by a combination of the Ames test (detects gene mutations) and the in vitro micronucleus test (MNvit), since the latter detects both chromosomal aberrations and aneuploidy. In this paper we therefore present an analysis of an existing database of rodent carcinogens and a new database of in vivo genotoxins in terms of the in vitro genotoxicity tests needed to detect their in vivo activity. Published in vitro data from at least one test system (most were from the Ames test) were available for 557 carcinogens and 405 in vivo genotoxins. Because there are fewer publications on the MNvit than for other mammalian cell tests, and because the concordance between the MNvit and the in vitro chromosomal aberration (CAvit) test is so high for clastogenic activity, positive results in the CAvit test were taken as indicative of a positive result in the MNvit where there were no, or only inadequate data for the latter. Also, because Hprt and Tk loci both detect gene-mutation activity, a positive Hprt test was taken as indicative of a mouse-lymphoma Tk assay (MLA)-positive, where there were no data for the latter. Almost all of the 962 rodent carcinogens and in vivo genotoxins were detected by an in vitro battery comprising Ames+MNvit. An additional 11 carcinogens and six in vivo genotoxins would apparently be detected by the MLA, but many of these had not been tested in the MNvit or CAvit tests. Only four chemicals emerge as potentially being more readily detected in MLA than in Ames+MNvit--benzyl acetate, toluene, morphine and thiabendazole--and none of these are convincing cases to argue for the inclusion of the MLA in addition to Ames+MNvit. Thus, there is no convincing evidence that any genotoxic rodent carcinogens or in vivo genotoxins would remain undetected in an in vitro test battery consisting of Ames+MNvit.
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Affiliation(s)
- David Kirkland
- Kirkland Consulting, PO Box 79, Tadcaster LS24 0AS, United Kingdom.
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Helmes CT, Atkinson DL, Jaffer J, Sigman CC, Thompson KL, Kelsey MI, Kraybill HF, Munn JI. Evaluation and classification of the potential carcinogenicity of organic air pollutants. ACTA ACUST UNITED AC 2008. [DOI: 10.1080/10934528209375038] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
| | | | - J. Jaffer
- a SRI International , Menlo Park, CA, 94025
| | | | | | - M. I. Kelsey
- b National Cancer Institute , Bethesda, MD, 20014
| | | | - J. I. Munn
- b National Cancer Institute , Bethesda, MD, 20014
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13
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Rosenkranz HS, Mermelstein R. The genotoxicity, metabolism and carcinogenicity of nitrated polycyclic aromatic hydrocarbons. ACTA ACUST UNITED AC 2008. [DOI: 10.1080/10590508509373334] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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14
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Neumann HG. Aromatic Amines in Experimental Cancer Research: Tissue-Specific Effects, an Old Problem and New Solutions. Crit Rev Toxicol 2008; 37:211-36. [PMID: 17453932 DOI: 10.1080/10408440601028603] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Carcinogenic aromatic amines usually produce tumors in specific target tissue, such as 2-acetylaminofluorene (AAF) producing liver tumors in rats, in contrast to some other structurally related arylamines. A hypothesis is presented that explains the mode of action in this rat liver model. Genotoxic and nongenotoxic effects work together and make AAF a complete rat liver carcinogen. The cytotoxic, promoting effects are particularly important. N-Hydroxy-2-aminofluorene and 2-nitrosofluorene, two metabolites of AAF, are able to uncouple the mitochondrial respiratory chain. They entertain a redox cycle that removes electrons from the respiratory chain and impairs ATP production. The dose-dependent opening of the mitochondrial permeability transition pore signals the viability of the cell. If the pore is opened to a certain extent, the cell is eliminated by apoptosis. As a consequence, oval cells proliferate, and as this process is overloaded, the liver transforms into a cirrhosis-like situation and thus provides the conditions under which initiated liver cells develop tumors. Such an interpretation is based on assumptions that have been debated for a long time. Some of these often forgotten developments are reviewed in support of the hypothesis, which allows a more comprehensive view of the complex in vivo situation at a time when in vitro models prevail.
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Affiliation(s)
- H-G Neumann
- Department of Toxicology, University of Würzburg, Germany.
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Ni W, McNaughton L, LeMaster DM, Sinha R, Turesky RJ. Quantitation of 13 heterocyclic aromatic amines in cooked beef, pork, and chicken by liquid chromatography-electrospray ionization/tandem mass spectrometry. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2008; 56:68-78. [PMID: 18069786 DOI: 10.1021/jf072461a] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The concentrations of heterocyclic aromatic amines (HAAs) were determined, by liquid chromatography-electrospray ionization/tandem mass spectrometry (LC-ESI-MS/MS), in 26 samples of beef, pork, and chicken cooked to various levels of doneness. The HAAs identified were 2-amino-3-methylimidazo[4,5- f]quinoline, 2-amino-1-methylimidazo[4,5- b]quinoline, 2-amino-1-methylimidazo[4,5- g]quinoxaline (I gQx), 2-amino-3-methylimidazo[4,5- f]quinoxaline, 2-amino-1,7-dimethylimidazo[4,5- g]quinoxaline (7-MeI gQx), 2-amino-3,8-dimethylimidazo[4,5- f]quinoxaline, 2-amino-1,6-dimethyl-furo[3,2- e]imidazo[4,5- b]pyridine, 2-amino-1,6,7-trimethylimidazo[4,5- g]quinoxaline, 2-amino-3,4,8-trimethylimidazo[4,5- f]quinoxaline, 2-amino-1,7,9-trimethylimidazo[4,5- g]quinoxaline, 2-amino-1-methyl-6-phenylimidazo[4,5- b]pyridine (PhIP), 2-amino-9 H-pyrido[2,3- b]indole, and 2-amino-3-methyl-9 H-pyrido[2,3- b]indole. The concentrations of these compounds ranged from <0.03 to 305 parts per billion (micrograms per kilogram). PhIP was the most abundant HAA formed in very well done barbecued chicken (up to 305 microg/kg), broiled bacon (16 microg/kg), and pan-fried bacon (4.9 microg/kg). 7-MeI gQx was the most abundant HAA formed in very well done pan-fried beef and steak, and in beef gravy, at concentrations up to 30 microg/kg. Several other linear tricyclic ring HAAs containing the I gQx skeleton are formed at concentrations in cooked meats that are relatively high in comparison to the concentrations of their angular tricyclic ring isomers, the latter of which are known experimental animal carcinogens and potential human carcinogens. The toxicological properties of these recently discovered I gQx derivatives warrant further investigation and assessment.
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Affiliation(s)
- Weijuan Ni
- Division of Environmental Disease Prevention and Division of Molecular Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12201-0509, USA
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Turesky RJ, Goodenough AK, Ni W, McNaughton L, LeMaster DM, Holland RD, Wu RW, Felton JS. Identification of 2-amino-1,7-dimethylimidazo[4,5-g]quinoxaline: an abundant mutagenic heterocyclic aromatic amine formed in cooked beef. Chem Res Toxicol 2007; 20:520-30. [PMID: 17316027 PMCID: PMC2533101 DOI: 10.1021/tx600317r] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A previously unknown isomer of the carcinogenic heterocyclic aromatic amine (HAA) 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (8-MeIQx) was recently discovered in the urine of meat eaters and subsequently detected in cooked ground beef (Holland, R.D., et al. (2004) Chem. Res. Toxicol. 17, 1121-1136). In this current investigation, the identity of the analyte was determined through a comparison of its chromatographic tR by HPLC and through UV and mass spectral comparisons to the synthesized isomers of 8-MeIQx. Angular tricyclic isomers of 8-MeIQx were excluded as potential structures of the newly discovered HAA, on the basis of dissimilar tR and product ion mass spectral data. The linear tricyclic isomers 2-amino-1,6-dimethylimidazo[4,5-g]quinoxaline (6-MeIgQx) and 2-amino-1,7-dimethylimidazo[4,5-g]quinoxaline (7-MeIgQx) were postulated as plausible structures. Both compounds were synthesized from 4-fluoro-5-nitro-benzene-1,2-diamine in five steps. The structure of the analyte was proven to be 7-MeIgQx, on the basis of co-injection of the compound with the synthetic isomers, and corroborated by comparisons of the UV and mass spectral data of the analyte and MeIgQx isomers. 7-MeIgQx induced 348 revertants/microg in the S. typhimurium tester strain YG1024, when liver S-9 homogenate of rats pretreated with polychlorinated biphenyls (PCBs) was used for bioactivation. This newly discovered 7-MeIgQx molecule is one of the most abundant HAAs formed in cooked ground beef patties and pan-fried scrapings. The human health risk of 7-MeIgQx requires investigation.
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Affiliation(s)
- Robert J Turesky
- Division of Environmental Disease Prevention, Wadsworth Center, New York State Department of Health, Albany, New York 12201, USA.
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Neumann HG, Bitsch A, Klöhn PC. The dual role of 2-acetylaminofluorene in hepatocarcinogenesis: specific targets for initiation and promotion. Mutat Res 1997; 376:169-76. [PMID: 9202753 DOI: 10.1016/s0027-5107(97)00040-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
2-Acetylaminofluorene (AAF) is one of the most widely studied model carcinogens. It produces liver tumors in rats. Comparison with other arylamides shows that promutagenic DNA lesions are necessary but not sufficient to explain this tissue-specific effect. Mutagenicity of AAF was studied in AS52 cells and compared with that of 2-acetylaminophenanthrene and trans-4-acetylaminostilbene which are incomplete carcinogens in rat liver. The major mutations were G to T transversions in all cases. All three acetamides acted as initiators in an initiation-promotion experiment with phenobarbital as a promoter. Chronic toxic effects of AAF were attributed to specific effects of AAF metabolites on mitochondrial respiration. Electron drainage by 2-nitrosofluorene causes an uncoupling effect on oxidative phosphorylation in vitro. Corresponding compensatory effects were observed in vivo. Initiating as well as promoting properties of AAF are therefore considered responsible for the generation of rat liver tumors. The results support the hypothesis that genotoxic effects generate initiated cells which begin to proliferate only when microcirculation is disturbed due to cirrhotic alterations. These are triggered by non-genotoxic interference with mitochondrial respiration and oxidative phosphorylation.
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Affiliation(s)
- H G Neumann
- Department of Toxicology, University of Würzburg, Germany
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18
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Koh WS, Yang KH, Jeong TC, Delany B, Kaminski NE. 2-Acetylaminofluorene inhibits the activation of immune responses by blocking cell cycle progression at G1 phase. Arch Toxicol 1995; 69:350-6. [PMID: 7654142 DOI: 10.1007/s002040050183] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
2-Acetylaminofluorene (AAF) inhibited in a dose dependent manner mouse spleen cell blastogenesis in response to phorbol 12-myristate 13-acetate (PMA)/Ionomycin (Io) activation, the T-cell lectin, concanavalin A (Con A), and following stimulation by alloantigens as measured by the mixed lymphocyte response (MLR). AAF also markedly suppressed the T-cell dependent antibody forming cell (AFC) response to sRBC. AAF was most inhibitory on both the sRBC IgM AFC response and Con A stimulated proliferation when added during the first 24 h following initiation of culture. Direct addition of high concentrations of AAF (100 microM) to spleen cell cultures at 48 h following Con A stimulation produced a very modest inhibition (< 20%) of T-cell proliferation as compared to 90% when added at the time cultures were initiated. Similarly, AAF (75 and 100 microM) produced a greater than 80% inhibition of the in vitro AFC response when spleen cells were sensitized with antigen in presence of AAF. In contrast, no inhibition of the IgM AFC response was produced when AAF (75 microM) was added to spleen cell cultures 48 or 72 h after antigen sensitization. Con A-triggered cell-cycle progression was attenuated at the G1 stage by the addition of AAF (50 and 100 microM) with no inhibition of S to G2/M phase transition. These results suggest that the mechanism of AAF-mediated immune suppression is through a blockade of cell cycle progression from G1 to S phase.
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Affiliation(s)
- W S Koh
- Department of Life Science, Korea Advanced Institute of Science and Technology, Taejon
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19
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Heflich RH, Neft RE. Genetic toxicity of 2-acetylaminofluorene, 2-aminofluorene and some of their metabolites and model metabolites. Mutat Res 1994; 318:73-114. [PMID: 7521935 DOI: 10.1016/0165-1110(94)90025-6] [Citation(s) in RCA: 174] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
2-Acetylaminofluorene and 2-aminofluorene are among the most intensively studied of all chemical mutagens and carcinogens. Fundamental research findings concerning the metabolism of 2-acetylaminofluorene to electrophilic derivatives, the interaction of these derivatives with DNA, and the carcinogenic and mutagenic responses that are associated with the resulting DNA damage have formed the foundation upon which much of genetic toxicity testing is based. The parent compounds and their proximate and ultimate mutagenic and carcinogenic derivatives have been evaluated in a variety of prokaryotic and eukaryotic assays for mutagenesis and DNA damage. The reactive derivatives are active in virtually all systems, while 2-acetylaminofluorene and 2-aminofluorene are active in most systems that provide adequate metabolic activation. Knowledge of the structures of the DNA adducts formed by 2-acetylaminofluorene and 2-aminofluorene, the effects of the adducts on DNA conformation and synthesis, adduct distribution in tissues, cells and DNA, and adduct repair have been used to develop hypotheses to understand the genotoxic and carcinogenic effects of these compounds. Molecular analysis of mutations produced in cell-free, bacterial, in vitro mammalian, and intact animal systems have recently been used to extend these hypotheses.
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Affiliation(s)
- R H Heflich
- Division of Genetic Toxicology, National Center for Toxicological Research, Jefferson, AR 72079
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20
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Ford GP, Herman PS. Relative stabilities of nitrenium ions derived from polycyclic aromatic amines. Relationship to mutagenicity. Chem Biol Interact 1992; 81:1-18. [PMID: 1730143 DOI: 10.1016/0009-2797(92)90023-e] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The relative energetics of arylamine N-hydroxylation and N-O heterolysis (ArNH2----ArNHOH----ArNH+) for condensed systems of two, three and four rings were calculated using semiempirical AM1 molecular orbital theory. The overall thermodynamics of N-hydroxylation were almost insensitive to the structure of the amine while differences in the energetics of nitrenium ion formation varied from 0 to 35 kcal mol-1. Limited correlations between the latter and the experimental TA98 and TA100 mutagenicities of the amines are presented.
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Affiliation(s)
- G P Ford
- Department of Chemistry, Southern Methodist University, Dallas, TX 75275
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Arylamine activation following chronic ethanol ingestion by rats: studies on the liver S9, microsomal and cytosolic fractions and comparison with Aroclor 1254 pretreatment. Mutat Res 1991; 247:153-66. [PMID: 2002800 DOI: 10.1016/0027-5107(91)90043-n] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
That enzyme fractions derived from animals chronically fed alcohol can alter the metabolism of carcinogenic xenobiotic compounds has been documented. To further understand this relationship the mutagenicity of 3 aromatic amines was determined in the Ames test, employing activation systems derived from rats maintained on an alcohol-containing liquid diet, an isocaloric control liquid diet or Aroclor 1254-pretreated animals fed standard laboratory chow. Depending upon protein and substrate concentrations, S9 from ethanol-fed rats was 30-50% less efficient than S9 from pair-fed rats in activating arylamines (2-aminofluorene, 2-aminoanthracene and 2-acetylaminofluorene) to mutagens in Salmonella typhimurium TA98 and TA100. Cytosolic fractions from ethanol-fed animals always resulted in greater arylamine activation than that of controls whereas the opposite was true of the microsomal compartment in which the ethanol-treated group was consistently less active than the controls. The cytosolic N-acetyltransferase activities with respect to 2 different substrates, isoniazid and 2-aminofluorene, were unaffected by ethanol consumption, indicating that this activity probably does not account for the different activation profiles exhibited by the ethanol and pair-fed cytosolic systems. Both the cytosolic and microsomal compartments are required for maximal expression of the mutagenicity of each arylamine however, each compartment can activate arylamines independently of the other. Reconstituting cytosol with microsomes from ethanol- and pair-fed rats, but not Aroclor-pretreated rats, resulted in a synergistic activation of the aromatic amines and displayed an effect similar to that of S9. Compared to Aroclor pretreatment and pair-fed controls, microsomes from ethanol-fed rats displayed the least capacity for activating any of the arylamines to mutagens. Microsomes from Aroclor-pretreated rats accounted for at least 80% of the S9-mediated activation of each of the arylamines to mutagenic metabolites which was in marked contrast to the contribution of the microsomal fractions to the S9 activity in the ethanol- (5-20% of S9 activity) and pair-fed systems (22-30% of S9 activity). The data indicate that 2 opposing reactions occur in S9, a cytosolic activity that augments and a microsomal activity that attenuates the mutagenicity of arylamines. Both activities are modified by ethanol consumption and Aroclor pretreatment.
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22
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Polycyclic aromatic compounds of environmental and occupational importance ? Their occurrence, toxicity and the development of high-purity certified reference materials. ACTA ACUST UNITED AC 1991. [DOI: 10.1007/bf00321499] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Watanabe M, Ishidate M, Nohmi T. Sensitive method for the detection of mutagenic nitroarenes and aromatic amines: new derivatives of Salmonella typhimurium tester strains possessing elevated O-acetyltransferase levels. Mutat Res 1990; 234:337-48. [PMID: 2215547 DOI: 10.1016/0165-1161(90)90044-o] [Citation(s) in RCA: 255] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Acetyl-CoA: N-hydroxyarylamine O-acetyltransferase is an enzyme involved in the intracellular metabolic activation of arylhydroxylamines derived from mutagenic nitroarenes and aromatic amines. The acetyltransferase gene of Salmonella typhimurium TA1538 was cloned into pBR322 and the plasmids harboring the gene were introduced into TA98 and TA100. The resulting strains (YG1024 and YG1029) had about 100 times higher 2-hydroxyamino-6-methyldipyrido[1,2-a:3',2'-d]-imidazole (N-hydroxy-Glu-P-1) O-acetyltransferase activity than TA1538 containing pBR322, and were extremely sensitive to the mutagenic actions of 2-nitrofluorene, 1-nitropyrene, 1,8-dinitropyrene, 2-amino-6-methyldipyrido[1,2-a:3',2-d)-imidazole (Glu-P-1), 2-aminofluorene and 2-aminoanthracene. These results indicate that the new strains permit the efficient detection of the mutagenicity of environmental nitroarenes and aromatic amines.
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Affiliation(s)
- M Watanabe
- Division of Genetics and Mutagenesis, National Institute of Hygienic Sciences, Tokyo, Japan
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24
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Watanabe M, Ishidate M, Nohmi T. A sensitive method for the detection of mutagenic nitroarenes: construction of nitroreductase-overproducing derivatives of Salmonella typhimurium strains TA98 and TA100. Mutat Res 1989; 216:211-20. [PMID: 2668749 DOI: 10.1016/0165-1161(89)90007-1] [Citation(s) in RCA: 134] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
'Classical nitroreductase' is an enzyme involved in the intracellular metabolic activation of mutagenic nitroarenes. The nitroreductase gene of Salmonella typhimurium TA1538 was cloned into pBR322 and the plasmids harboring the gene were introduced into TA98 and TA100. The resulting strains (YG1021 and YG1026) had more than 50 times higher nitrofurazone-reductase activity than TA1538 containing pBR322, and were extremely sensitive to the mutagenic action of 2-nitrofluorene, 1-nitropyrene and 2-nitronaphthalene. These results indicate that the new strains permit the efficient detection of mutagenic nitroarenes.
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Affiliation(s)
- M Watanabe
- Division of Mutagenesis, National Institute of Hygienic Sciences, Tokyo, Japan
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25
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Franz R, Neumann HG. Reaction of trans-4-N-acetoxy-N-acetylaminostilbene with guanosine and deoxyguanosine in vitro: the primary reaction product at N2 of guanine yields different final adducts. Chem Biol Interact 1988; 67:105-16. [PMID: 3168079 DOI: 10.1016/0009-2797(88)90090-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The model ultimate carcinogen, trans-4-N-acetoxy-N-acetylaminostilbene (N-acetoxy-AAS), was reacted with guanosine (Guo) and deoxyguanosine (d-Guo) and the resulting adducts were purified by Sephadex LH-20 chromatography and HPLC for structure identification. A number of new adducts was identified by mass and 1H-NMR spectroscopy. The generation of all known adducts can now be explained by a common mechanism. The electrophile formed from the hydroxamic acid ester at C-beta reacts in a first step predominantly with N2 of guanine (Gua). The resulting quinone-imide intermediate reacts in a second step with either one of three nucleophiles: (1) predominantly with N3 of Gua to yield the previously described angular cyclic adducts ((5R,6R)/(5S,6S)-9-oxo-5,6,7,9-tetrahydro-imidazo(2,1-b)purines); (2) with N1 of Gua to yield linear cyclic adducts ((6R,7R)/(6S,7S)-9-oxo-5,6,7,9-tetrahydro-imidazo(1,2-a)purines); (3) with water to yield the open ring (1R,2R)/(1S,2S)-2-(N2'-guanyl)-1-hydroxyethanes. To some minor extent (1:8-1:9) the electrophile reacts first with N1 or N3 of guanine which leads to the formation of two pairs of the corresponding regioisomeric cyclic adducts. This reaction mechanism may also explain the formation of cross-links between different bases.
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Affiliation(s)
- R Franz
- Institute of Pharmacology and Toxicology, University of Würzburg, F.R.G
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26
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Mullin CA, Rashid KA, Mumma RO. Mutagenic potency of some conjugated nitroaromatic compounds and its relationship to structure. Mutat Res 1987; 188:267-74. [PMID: 3302696 DOI: 10.1016/0165-1218(87)90003-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The mutagenicities of 12 conjugated non-fused nitroaromatic compounds and 1 amino analogue were determined in strains TA100 and TA98 of Salmonella typhimurium. Reversions by p-nitroaromatics increased in the order of the acetophenone, benzaldehyde, styrene, chalcone, cinnamic acid and stilbene indicating the importance for mutagenic potency of extended conjugation to the p-nitrophenyl substituent. Highest mutagenicity was found with alpha-substituted 4-nitrostyryl derivatives of which the phenyl derivative (31 revertants per nmole in TA100) was the most active. Generally, the TA100 strain was more sensitive than TA98 to these mutagens and S9 treatment was unnecessary for activity, although 4-nitrochalcone required S9 activation. Para-nitro isomers of the cinnamic acids and chalcones were much more active than the corresponding ortho and meta isomers. The 4-aminocinnamic acid analogue was inactive suggesting that complete reduction in Salmonella of 4-nitrocinnamic acid to an active amino derivative is not response for the high mutagenicity of the former. Mutagenicity of these p-nitrostyryl compounds may be explained by the covalent interaction of the electrophilic benzylic carbon with Salmonella DNA.
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27
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Yoshioka T, Takou Y, Uematsu T. Mutagenicity of N-arylacetohydroxamic acids and their O-glucosides derived from chlorinated 4-nitrobiphenyl ethers. Mutat Res 1986; 170:93-102. [PMID: 3520306 DOI: 10.1016/0165-1218(86)90021-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The mutagenic activity of N-arylacetohydroxamic acids, their O-acetates, their O-glucosides, and N-arylhydroxylamines, derived from chlorinated 4-nitrobiphenyl ethers (CNBs), was tested in the Salmonella reversion assay. N-Arylhydroxylamines were mutagenic by themselves; however, other compounds containing an N-acetyl group showed mutagenic activity in the presence of guinea pig liver S9. The mutagenic activation of the glucosides of N-arylacetohydroxamic acids was caused by Ms but not by S10.5, whereas their aglycones, N-arylacetohydroxamic acids, were activated to mutagens by both the fractions. The mutagenic activation of these compounds was inhibited by bis(p-nitrophenyl)phosphate, which indicates that enzymatic deacetylation is a crucial step in the mutagenic activation. Analysis of metabolites of the O-glucosides of N-arylacetohydroxamic acids by h.p.l.c. indicates that the corresponding deacetylated O-glucosides are primary metabolites, which decomposed to amino and azoxy (via hydroxylamine) derivatives, and that the deacetylating activity of S9 locates exclusively in Ms.
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Abstract
Mutagenic activity was observed in sediments of the Suimon River bed with and without S9 mix. The direct-acting mutagens in the sediment were investigated. The sediment was extracted with methanol and fractionated on a Silica gel column. The benzene fraction from the Silica gel column exhibited mutagenic activity without S9 mix in strain TA98, while it failed to show mutagenic activity in nitroreductase-deficient strain TA98NR. This observation led to the suspicion that nitro compounds were the direct-acting mutagens of these samples. The benzene fraction was treated by heptafluorobutyric anhydride (HFBA) and investigated with gas chromatography equipped with an electron capture detector (GC-ECD). 2-Nitrofluorene, 4,4'-dinitrobiphenyl, 2,7-dinitrofluorene and 1-nitropyrene were detected and measured quantitatively. The mutagenic activity of a mixture of these compounds was compared with that of the original fraction and the direct-acting mutagenicity of Suimon River sediment can be explained by these nitroarenes, especially 1-nitropyrene.
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29
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Fu PP, Chou MW, Miller DW, White GL, Helflich RH, Beland FA. The orientation of the nitro substituent predicts the direct-acting bacterial mutagenicity of nitrated polycyclic aromatic hydrocarbons. Mutat Res 1985; 143:173-81. [PMID: 3892279 DOI: 10.1016/s0165-7992(85)80031-2] [Citation(s) in RCA: 99] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Tsuruta Y, Josephy PD, Rahimtula AD, O'Brien PJ. Peroxidase-catalyzed benzidine binding to DNA and other macromolecules. Chem Biol Interact 1985; 54:143-58. [PMID: 4028287 DOI: 10.1016/s0009-2797(85)80159-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
[14C]Benzidine is rapidly oxidized by a peroxidase/H2O2 system to products which bind irreversibly to DNA. The presence of exogenous DNA also prevented benzidine polymerization to 'benzidine brown' and azobenzidine. Two molar equivalents of H2O2 were required to oxidize the benzidine and achieve maximal DNA binding. Furthermore, 95% of the benzidine was trapped and 36 nmol benzidine was bound per mg DNA. Polyriboguanylic acid was as effective as DNA in binding benzidine, but polyriboadenylic acid, polyribouridylic acid and polyribocytidylic acid were much less effective. Binding of [14C]benzidine correlated well with the absorbance at 295 nm and 390 nm of the modified DNA or various synthetic homopolymers of ribonucleotides isolated from the reaction mixture. The peroxidase/H2O2 system also catalyzed the binding of dichlorobenzidine, o-tolidine and o-dianisidine to DNA but 3,5,3',5'-tetramethylbenzidine, a non-carcinogen, did not bind. The binding could be prevented by various biological hydrogen donors, thiols, or phenolic antioxidants. The mechanisms for DNA protection were investigated; the oxidized benzidine species involved in binding can be reduced with ascorbate, NADPH, or thiols, and trapped by thiols or phenolic antioxidants to form conjugates or adducts.
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Hilpert D, Neumann HG. Accumulation and elimination of macromolecular lesions in susceptible and non-susceptible rat tissues after repeated administration of trans-4-acetylaminostilbene. Chem Biol Interact 1985; 54:85-95. [PMID: 2410150 DOI: 10.1016/s0009-2797(85)80154-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Trans-4-acetylaminostilbene (trans-AAS) is a potent carcinogen and quite specifically produces sebaceous gland tumors, predominantly in the Zymbal's gland of rats. It is also acutely toxic to the rat glandular stomach. Recent results have shown that these target tissues are not notably exposed to reactive metabolites after single administration of the compound. Therefore, experiments were designed to test whether multiple exposures cause changes in metabolic activation or repair of DNA-bound metabolites to the effect that target and non-target tissues accumulate macromolecular damage differently. Trans-[3H]AAS was orally administered to female Wistar rats in 12 doses over 6 weeks and binding of metabolites to proteins, RNA and DNA in several tissues as well as the pattern of adducts in liver nucleic acids were measured. In addition, the elimination of macromolecular-bound metabolites was determined at various intervals during the treatment. Metabolism and clearance of bound metabolites remained unaltered. As a consequence, DNA-bound metabolites accumulated in all tissues measured; to the greatest extent in the non-target tissues liver and kidney. Tissue exposure, as estimated by protein-binding, differed by a factor of 10 and decreased in the following order: liver, kidney, lung, Zymbal's gland, glandular stomach, mammary tissue. The results support the notion that neither the extent nor the persistence of DNA-binding correlate with the biological effects of trans-AAS.
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32
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White GL, Heflich RH. Mutagenic activation of 2-aminofluorene by fluorescent light. TERATOGENESIS, CARCINOGENESIS, AND MUTAGENESIS 1985; 5:63-73. [PMID: 2859663 DOI: 10.1002/tcm.1770050108] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
To determine the effect of artificially produced light on the direct mutagenicity of 2-aminofluorene, that arylamine was irradiated with either sun, cool-white, black, blue, or yellow fluorescent light or held in the dark prior to assaying for mutagenicity using Salmonella typhimurium strain TA98. The effectiveness of these exposures in potentiating the mutagenicity of 2-aminofluorene was sun greater than black greater than cool-white greater than blue greater than yellow approximately equal to dark. By varying the radiant flux densities produced by the lamps and using optical filters, wavelengths of light up to approximately 450 nm were found to be effective in the mutagenic potentiation. Studies using radical scavengers and oxygen modifiers indicated that the light-induced mutagenicity was dependent on oxygen and that singlet oxygen may be an effective activator of 2-aminofluorene. The mutagenicity of fluorene was not increased by exposure to light, while only sunlight potentiated the mutagenicity of 2-acetylaminofluorene. This result suggested the importance of the primary amine in the mutagenic activation of 2-aminofluorene by light. Light-activated 2-aminofluorene was less mutagenic in strains TA98NR and TA98/1,8-DNP6 than in TA98. This observation, combined with the dependence of the photoactivation on oxygen and amino-substitution, indicated that the light-enhanced mutagenicity was at least partially due to N-oxidized photoproducts. These studies indicate that the effect of light on environmental contaminants must be considered in assessing their genotoxic potential.
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Klopman G, Frierson MR, Rosenkranz HS. Computer analysis of toxicological data bases: mutagenicity of aromatic amines in Salmonella tester strains. ENVIRONMENTAL MUTAGENESIS 1985; 7:625-44. [PMID: 3899629 DOI: 10.1002/em.2860070503] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
There is an increasing problem in the world of toxicological evaluation in that, while test results of new compounds are appearing regularly, traditional methods of analysis of such data are cumbersome and slow. The new computer program CASE (computer automated structure evaluator) was designed to handle just such problems. It analyzes molecules and their associated biological activity on the basis of structural fragments found and identified by the program as being important for the activity based on statistical tests of significance. The program was used to examine mutagenicity in Salmonella typhimurium strains TA98 and TA100 (with S9 activation) of approximately 80-100 aromatic amines. The resulting structural features were then used in a predictive fashion to test the expected mutagenic properties of a smaller set of about 20 compounds.
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Schmeiser HH, Pool BL, Wiessler M. Mutagenicity of the two main components of commercially available carcinogenic aristolochic acid in Salmonella typhimurium. Cancer Lett 1984; 23:97-101. [PMID: 6378360 DOI: 10.1016/0304-3835(84)90067-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
One of the 2 main components of the commercially available carcinogenic aristolochic acid (AA) was isolated, the other was enriched. Three different aristolochic acid samples (AAI 99% pure; AAI 65% + AAII 35%; AAI 32% + AAII 68%) were assayed for mutagenic activity in Salmonella typhimurium TA1537, TA100 and TA100 NR with and without the addition of a metabolizing mixture. The two main components (AAI and AAII) were direct mutagens in Salmonella strains TA1537 and TA100 with almost equal mutagenic potency. In TA100 NR the aristolochic acid samples showed no or only a very low level of biological activity, indicating the necessity of nitroreduction for the bioactivation of the samples. These findings suggest that both AAI as well as AAII can be used in further studies to elucidate the metabolism of aristolochic acid.
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Schut HA, Castonguay A. Metabolism of carcinogenic amino derivatives in various species and DNA alkylation by their metabolites. Drug Metab Rev 1984; 15:753-839. [PMID: 6437779 DOI: 10.3109/03602538409041079] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Rosenkranz HS, Mermelstein R. Mutagenicity and genotoxicity of nitroarenes. All nitro-containing chemicals were not created equal. Mutat Res 1983; 114:217-67. [PMID: 6300670 DOI: 10.1016/0165-1110(83)90034-9] [Citation(s) in RCA: 514] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The nitrated polycyclic aromatic hydrocarbons constitute a group of chemicals of environmental concern which display a broad spectrum of mutagenic, genotoxic and carcinogenic properties. Some members of the group are the most potent direct-acting bacterial mutagens while others exhibit low levels of potencies which require metabolic activation mixtures. Bacterial mutagenicity is dependent upon reduction of the nitro function. In mammalian cell systems the genetic and genotoxic effects of these nitrated chemicals include the induction of unscheduled DNA synthesis, sister-chromatid exchanges, chromosomal aberrations, gene mutations and cell transformation. The qualitative as well as quantitative expression of these effects is dependent upon the species and tissue of origin as well as culture history of the cell which in turn determine their enzymic capabilities and the conversion of these nitroarenes to ultimate mutagens and genotoxicants. In eukaryotic cells the following bioactivation pathways have been recognized: (a) reduction of the nitro moiety, (b) ring oxidation (the nature of which is influenced by the nitro function) followed by reduction of the nitro group, and (c) ring oxidation without concomitant reduction of the nitro moiety.
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Vance WA, Chan R. Dinitro and mononitrobenzo(ghi)perylenes and mononitrocoronene are highly mutagenic in the Ames Salmonella assay. ENVIRONMENTAL MUTAGENESIS 1983; 5:859-69. [PMID: 6653506 DOI: 10.1002/em.2860050610] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Benzo(ghi)perylene (B(ghi))Per, (191-24-2)) and coronene (Cor, (191-07-1)) are major constituents of the polycyclic aromatic hydrocarbons (PAH) found in automobile exhaust and polluted air [eg, Grimmer et al, 1981]. Nitration of these PAH by NO2 and traces of HNO3, which are also formed in automobile exhaust, seems highly probable. To identify the presence of these nitroarenes in environmental samples and to examine their mutagenic potencies we synthesized and characterized nitro derivatives of both PAH. 5-NO2B(ghi)Per (81316-87-2) and 1-NO2Cor (81316-84-9) produced 405 and 340 revertants/nmole respectively in TA98 in the presence of 0.6 mg of microsomal enzymes (S-9) per plate in the Ames test. 5,8-diNO2B(ghi)Per (83292-25-5) and 5,10-diNO2B(ghi)Per (83292-26-6) produced 21,500 and 4,000 revertants/nmole in TA98 without microsomal activation. Mutagenicity for the dinitrobenzo(ghi)perylenes was also high in TA98NR and TA97 but was reduced by 97% in TA98-1,8DNP. There is close similarity in the orientation and distances between reactive sites (nitrenium ion and carbocation) on the dinitrobenzo(ghi)perylenes and 1,6-dinitropyrene (42397-64-8) and 1,8-dinitropyrene (42397-65-9).
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Neumann HG. Role of extent and persistence of DNA modifications in chemical carcinogenesis by aromatic amines. Recent Results Cancer Res 1983; 84:77-89. [PMID: 6844703 DOI: 10.1007/978-3-642-81947-6_5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The initial step in tumor formation with aromatic amines is assumed to involve the modification of nucleic acids. Reactive metabolites bind covalently to purine and pyrimidine bases. The extent of formation of DNA adducts and their persistence is therefore expected to correlate with the biological effect. Using [3H]trans-4-amino-stilbene derivatives as model compounds, several parameters have been measured in susceptible and nonsusceptible rat tissues: total initial DNA binding, initial pattern of adducts, persistence of DNA adducts, accumulation of DNA binding after repeated doses, and persistence of DNA adducts after repeated doses. They did not correlate with tissue susceptibility. The tissue burden decreased in the order: liver greater than kidney greater than lung greater than glandular stomach greater than Zymbal gland. The latter tissue is the primary target for tumor formation. Comparison with other aromatic amines shows that aminostilbene derivatives are no exceptions. The role of specific nucleic acid modifications for mutagenic and carcinogenic effects is also difficult to evaluate in these cases. It is therefore emphasized that modulation of secondary steps in the multistage process may largely influence the final outcome. The role of cell proliferation and its stimulation as well as tumor promoting effects are discussed. Aminostilbene derivatives appear to produce primary lesions quite efficiently in rat liver but lack cytotoxic and promoting properties for this tissue.
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Evans FE, Miller DW. Conformation and dynamics associated with the site of attachment of a carcinogen to a nucleotide. Biochem Biophys Res Commun 1982; 108:933-9. [PMID: 7181894 DOI: 10.1016/0006-291x(82)92088-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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McCoy EC, McCoy GD, Rosenkranz HS. Esterification of arylhydroxylamines: evidence for a specific gene product in mutagenesis. Biochem Biophys Res Commun 1982; 108:1362-7. [PMID: 6758776 DOI: 10.1016/0006-291x(82)92150-7] [Citation(s) in RCA: 88] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Bock-Hennig BS, Ullrich D, Bock KW. Activating and inactivating reactions controlling 2-naphthylamine mutagenicity. Arch Toxicol 1982; 50:259-66. [PMID: 7149991 DOI: 10.1007/bf00310858] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Factors controlling 2-naphthylamine mutagenicity were studied using the Ames test. 1) Both rat liver microsomes and cytosolic proteins were required for generation of mutagenic metabolites. 2) 1-Hydroxy-2-naphthylamine, the major metabolite of 2-naphthylamine, was not mutagenic but cytotoxic to bacteria. 3) Ascorbic acid, reduced glutathione and conjugation reactions, such as glucuronidation, were strongly inhibiting 2-naphthylamine mutagenicity. 4) When isolated hepatocytes were used as the activating system mutagenic metabolites could not be detected. However cytotoxicity was detectable at doses of 2-naphthylamine greater than 0.2 mumol/10(6) cells. The results suggest that the formation of genotoxic metabolites of 2-naphthylamine is largely prevented in the intact, non-dividing rat hepatocyte.
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Fu PP, Heflich RH, Casciano DA, Huang AY, Trie WM, Kadlubar FF, Beland FA. Biologically active aromatic amines derived from carcinogenic polycyclic aromatic hydrocarbons: synthesis and mutagenicity of aminobenzo[a]pyrenes. Mutat Res 1982; 94:13-21. [PMID: 7048083 DOI: 10.1016/0027-5107(82)90164-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The mutagenicities of 6-aminobenzo[a]pyrene (6-NH2-BP), 4-, 11- and 12-NH2-BP, and two N,N-diacetyl derivatives (4- and 12-N(Ac)2-BP) were compared to that of the present compound, BP, and to the aromatic amine, 2-aminofluorene (AF), in the Ames' Salmonella typhimurium assay. In the presence of an S9 activating system all the compounds were mutagenic in strains TA100, TA98 and TA1538 was 4-NH2-BP greater than 4-N(Ac)2-BP greater than 12-NH2-BP greater than 12-N(Ac)2-BP greater than AF greater than 11-NH2-BP congruent to BP greater than 6-NH2-BP; whereas in strain TA100, the order was 4-NH2-BP greater than 4-N(Ac)2-BP greater than BP greater than 12-NH2-BP congruent to 12-N(Ac)2-BP congruent to 11-NH2-BP greater than 6-NH2-BP congruent to AF. Inclusion of the deacylase inhibitor, paraoxon, in the incubation decreased the mutagenicity of 4-N(Ac)2-BP but had no effect on its primary amine. These data suggest that, at least for this group of compounds, arylamines derived from carcinogenic polycyclic aromatic hydrocarbons are activated to potent mutagens primarily through S9-mediated metabolism (e.g., N-oxidation) of the amine.
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Lipkowitz KB, Chevalier T, Widdifield M, Beland FA. Force field conformational analysis of aminofluorene and acetylaminofluorene substituted deoxyguanosine. Chem Biol Interact 1982; 40:57-76. [PMID: 7074713 DOI: 10.1016/0009-2797(82)90028-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The hepatocarcinogen N-hydroxy-2-acetylaminofluorene forms two C8-substituted deoxyguanosine adducts in vivo. The conformation of these adducts, as well as 2'-deoxyguanosine and 8-amino-2'-deoxyguanosine has been studied with Allinger's force field. Using the glycoside rotation as a reaction coordinate, multidimensional potential energy surface were determined by relaxing all internal degrees of freedom. The calculations indicate the 2'-deoxyguanosine should exist as a mixture of syn and anti forms, that the syn form is slightly favored for 8-amino-2'-deoxyguanosine, that N-(deoxyguanosin-8-yl)-2-acetylaminofluorene (dG-C8-AAF) will only be found in the syn conformation and that, although the syn form is also more stable for N-(deoxyguanosin-8-yl)-2-aminofluorene (dG-C8-AF), it will have a substantially greater proportion of the anti-conformer than is found with dG-C8-AAF. The results of the force field calculations are discussed in relation to the effects these adducts may have on DNA structure.
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El-Bayoumy K, LaVoie EJ, Tulley-Freiler L, Hecht SS. Effects of ortho-methyl substituents on the mutagenicity of aminobiphenyls and aminonaphthalenes. Mutat Res 1981; 90:345-54. [PMID: 7038458 DOI: 10.1016/0165-1218(81)90057-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A series of aminobiphenyls and aminonaphthalenes were assayed for mutagenicity toward S. typhimurium, in the presence of rat liver 9000 g supernatant, to investigate the effects of positional isomerism and ortho-methyl substitution. Among the 3 possible aminobiphenyl isomers, only 4-aminobiphenyl was a potent mutagen, showing activity in S. typhimurium TA1538 and TA100, but not TA1535. 4-Amino-3-methylbiphenyl was a more potent mutagen in S. typhimurium TA1538 than was 4-aminobiphenyl, whereas both 3-amino-4-methylbiphenyl and 3-aminobiphenyl were inactive in this strain. 3-Amino-4-methylbiphenyl was mutagenic in S. typhimurium TA100, in contrast to 3-aminobiphenyl. These results demonstrate the enhancing effect of an ortho-methyl group on mutagenicity in the aminobiphenyls, which contrasts to the inhibitory effect of methyl substitution frequently observed in the 4-nitrobiphenyl system. Among the 2-aminonaphthalenes, 2-amino-3-methylnaphthalene was the most mutagenic compound in S. typhimurium TA1538, followed by 2-amino-1-methylnaphthalene and 2-aminonaphthalene. In S. typhimurium TA1535, however, 2-aminonaphthalene was a more potent mutagen than either of the ortho-methyl substituted derivatives. No significant mutagenic activity was observed for either 1-aminonaphthalene or 1-amino-2-methylnaphthalene in S. typhimurium TA1538 and TA1535. However, 1-aminoanaphthalene was weakly mutagenic in S. typhimurium TA 100.
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Abstract
The mutagenic activity of all 4 isomeric aminocarbazoles and 4 nitrocarbazoles was evaluated in Salmonella typhimurium tester strains TA98. TA100 and TA1535. All compounds were assayed both in the presence and absence of liver homogenate from Aroclor-treated rats. Among the aminocarbazoles, 2-aminocarbazole was found to be most active in both tester strains, although somewhat less active than 2-aminofluorene. 3-Aminocarbazole was the only other isomer that was mutagenic towards TA98 at the dose levels employed (5--200 micrograms). 4-Aminocarbazole was moderately active in TA100, and 1-aminocarbazole was inactive in both TA98 and TA100. Similar differences in mutagenic potency and specificity towards the tester strains were observed for the related series of nitrocarbazoles.
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McCoy EC, Rosenkranz EJ, Petrullo LA, Rosenkranz HS, Mermelstein R. Structural basis of the mutagenicity in bacteria of nitrated naphthalene and derivatives. ENVIRONMENTAL MUTAGENESIS 1981; 3:499-511. [PMID: 7026224 DOI: 10.1002/em.2860030502] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
While 2-nitronaphthalene was a weak direct-acting base-substitution mutagen (1.4 revertants/nanomole) for Salmonella typhimurium, the analogous nitronaphthalic acid anhydride and imides were moderate frameshift mutagens (approximately 20 rev/nanomole in strain TA98). Although imide derivatives are efficient DNA intercalators, mutagenicity data indicate that the bulk of the frameshift activity is derived from adduct formation between hydroxylamine intermediates and DNA. The low level of frameshift activity (approximately 8% of total) resulting from simple intercalation (measured in strain TA 1537) is not dependent upon reduction of the nitro function. Evidence is presented that suggests that the reduction of the nitro function to the corresponding hydroxylamine might not involve a free nitroso intermediate. The introduction of a second nitrofunction into nitronaphthalenes results in great positional effects of the various isomers on mutagenic activity and specificity.
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Heflich RH, Hazard RM, Lommel L, Scribner JD, Maher VM, McCormick JJ. A comparison of the DNA binding, cytotoxicity and repair synthesis induced in human fibroblasts by reactive derivatives of aromatic amide carcinogens. Chem Biol Interact 1980; 29:43-56. [PMID: 7356535 DOI: 10.1016/0009-2797(80)90085-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The cytotoxicity of three structurally-related direct-acting carcinogens, N-acetoxy-2-acetylaminofluorene, N-acetoxy-2-acetylaminophenanthrene and N-acetoxy-4-acetylaminobiphenyl, was compared in normal cells and in excision repair deficient xeroderma pigmentosum cells (XP12BE). All three proved significantly more cytotoxic to the XP cells than to the normal cells. At equicytoxic levels, substantially more residues were initially bound to the DNA of the normal cells than to the XP cells, suggesting that the former are able to remove a large percentage of the DNA bound residues before these can result in cell death. The ability of these cell strains to remove bound residues from DNA, to incorporate thymidine into parental strands of DNA during repair replication, and to recover from potentially lethal damage if held in the non-replicating, density-inhibited G0 state was compared as a function of dose and time. The XP12BE cells proved virtually incapable of excision repair of DNA damage induced by these carcinogens and of recovery. In contrast, normal cells recovered from the potentially lethal effects of these three compounds and did so at a rate comparable to their rate of removal of bound residues and of repair synthesis. In the excision-deficient XP12BE cells, DNA adducts induced by N-acetoxy-2-acetylaminophenanthrene proved 3- to 6-fold more cytotoxic than adducts induced by the other two carcinogens.
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Scribner JD, Koponen G. Binding of the carcinogen 2-acetamidophenanthrene to rat liver nucleic acids: lack of correlation with carcinogenic activity, and failure of the hydroxamic acid ester model for in vivo activation. Chem Biol Interact 1979; 28:201-9. [PMID: 95104 DOI: 10.1016/0009-2797(79)90161-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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