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Inesta-Vaquera F, Miyashita L, Grigg J, Henderson CJ, Wolf CR. Defining the in vivo mechanism of air pollutant toxicity using murine stress response biomarkers. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 888:164211. [PMID: 37196967 DOI: 10.1016/j.scitotenv.2023.164211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 05/10/2023] [Accepted: 05/12/2023] [Indexed: 05/19/2023]
Abstract
Air pollution can cause a wide range of serious human diseases. For the informed instigation of interventions which prevent these outcomes there is an urgent need to develop robust in vivo biomarkers which provide insights into mechanisms of toxicity and relate pollutants to specific adverse outcomes. We exemplify for a first time the application of in vivo stress response reporters in establishing mechanisms of air pollution toxicity and the application of this knowledge in epidemiological studies. We first demonstrated the utility of reporter mice to understand toxicity mechanisms of air pollutants using diesel exhaust particles compounds. We observed that nitro-PAHs induced Hmox1 and CYP1a1 reporters in a time- and dose-dependent, cell- and tissue-specific manner. Using in vivo genetic and pharmacological approaches we confirmed that the NRF2 pathway mediated this Hmox1-reporter induction stress reporter activity. We then correlated the activation of stress-reporter models (oxidative stress/inflammation, DNA damage and Ah receptor -AhR- activity) with responses in primary human nasal cells exposed to chemicals present in particulate matter (PM; PM2.5-SRM2975, PM10-SRM1648b) or fresh roadside PM10. To exemplify their use in clinical studies, Pneumococcal adhesion was assessed in exposed primary human nasal epithelial cells (HPNEpC). The combined use of HPNEpC and in vivo reporters demonstrated that London roadside PM10 particles induced pneumococcal infection in HPNEpC mediated by oxidative stress responses. The combined use of in vivo reporter models with human data thus provides a robust approach to define the relationship between air pollutant exposure and health risks. Moreover, these models can be used in epidemiological studies to hazard ranking environmental pollutants by considering the complexity of mechanisms of toxicity. These data will facilitate the relationship between toxic potential and the level of pollutant exposure in populations to be established and potentially extremely valuable tools for intervention studies for disease prevention.
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Affiliation(s)
- Francisco Inesta-Vaquera
- Division of Systems Medicine, School of Medicine, University of Dundee, Jacqui Wood Cancer Centre, Ninewells Hospital, Dundee DD1 9SY, UK
| | | | | | - Colin J Henderson
- Division of Systems Medicine, School of Medicine, University of Dundee, Jacqui Wood Cancer Centre, Ninewells Hospital, Dundee DD1 9SY, UK
| | - C Roland Wolf
- Division of Systems Medicine, School of Medicine, University of Dundee, Jacqui Wood Cancer Centre, Ninewells Hospital, Dundee DD1 9SY, UK.
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Nimesulide increases the aldehyde oxidase activity of humans and rats. Acta Pharmacol Sin 2020; 41:843-851. [PMID: 31913347 PMCID: PMC7471466 DOI: 10.1038/s41401-019-0336-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 11/18/2019] [Indexed: 11/09/2022] Open
Abstract
An increasing number of drugs are metabolized by aldehyde oxidase (AOX), but AOX-mediated drug interactions are seldom reported due to the lack of appropriate inhibitors and inducers. A recent study reported that nimesulide (NIM) could increase the liver injury risk of methotrexate. The latter was mainly metabolized by AOX to form hepatotoxic 7-hydroxymethotrexate (7-OH MTX). Thus, we speculated that NIM could induce AOX. In this study, we investigated the potential induction of AOX activity by NIM using methotrexate as the probe substrate. Treatment of primary human and rat hepatocytes with NIM (20 μM) for 24 h caused a 2.0- and 3.1-fold, respectively, increase in 7-OH MTX formation. Oral administration of NIM (100 mg·kg−1·d−1, for 5 days) to rats significantly increased the systematic exposure (6.5-fold), liver distribution (2.5-fold), and excretion (5.2-fold for urinary excretion and 2.1-fold for fecal excretion) of 7-OH MTX. The 7-OH MTX formation in liver cytosol from rats pretreated with 20, 50, and 100 mg·kg−1·d−1 NIM for 5 days increased by 1.9-, 3.2-, and 3.7-fold, respectively, compared with that of rats pretreated with the vehicle. We revealed that the elevation of AOX activity was accompanied by an increase in AOX1 protein levels but not the corresponding mRNA levels. Collectively, our results demonstrate for the first time that NIM can increase the AOX activity of humans and rats, and may raise concerns regarding the risk of drug interactions between NIM and AOX substrates in clinical practice.
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Murray JR, Mesaros CA, Arlt VM, Seidel A, Blair IA, Penning TM. Role of Human Aldo-Keto Reductases in the Metabolic Activation of the Carcinogenic Air Pollutant 3-Nitrobenzanthrone. Chem Res Toxicol 2018; 31:1277-1288. [PMID: 30406992 DOI: 10.1021/acs.chemrestox.8b00250] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
3-Nitrobenzanthrone (3-NBA) is a potent mutagen and suspected human carcinogen detected in diesel exhaust particulate and ambient air pollution. It requires metabolic activation via nitroreduction to promote DNA adduct formation and tumorigenesis. NAD(P)H:quinone oxidoreductase 1 (NQO1) has been previously implicated as the major nitroreductase responsible for 3-NBA activation, but it has recently been reported that human aldo-keto reductase 1C3 (AKR1C3) displays nitroreductase activity toward the chemotherapeutic agent PR-104A. We sought to determine whether AKR1C isoforms could display nitroreductase activity toward other nitrated compounds and bioactivate 3-NBA. Using discontinuous enzymatic assays monitored by UV-HPLC, we determined that AKR1C1-1C3 catalyze three successive two-electron nitroreductions toward 3-NBA to form the reduced product 3-aminobenzanthrone (3-ABA). Evidence of the nitroso- and hydroxylamino- intermediates were obtained by UPLC-HRMS. Km, kcat, and kcat/ Km values were determined for recombinant AKR1C and NQO1 and compared. We found that AKR1C1, AKR1C3, and NQO1 have very similar apparent catalytic efficiencies (8 vs 7 min-1 mM-1) despite the higher kcat of NQO1 (0.058 vs 0.012 min-1). AKR1C1-1C3 possess a Km much lower than that of NQO1, which suggests that they may be more important than NQO1 at the low concentrations of 3-NBA to which humans are exposed. Given that inhalation represents the primary source of 3-NBA exposure, we chose to evaluate the relative importance of AKR1C1-1C3 and NQO1 in human lung epithelial cell lines. Our data suggest that the combined activities of AKR1C1-1C3 and NQO1 contribute equally to the reduction of 3-NBA in A549 and HBEC3-KT cell lines and together represent approximately 50% of the intracellular nitroreductase activity toward 3-NBA. These findings have significant implications for the metabolism of nitrated polycyclic aromatic hydrocarbons and suggest that the hitherto unrecognized nitroreductase activity of AKR1C enzymes should be further investigated.
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Affiliation(s)
| | | | - Volker M Arlt
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health , King's College London , SE1 9NH , United Kingdom.,NIHR Health Protection Research Unit in Health Impact of Environmental Hazards , King's College London in partnership with Public Health England and Imperial College London , London SE1 9NH , United Kingdom
| | - Albrecht Seidel
- Biochemical Institute for Environmental Carcinogens, Prof. Dr. Gernot Grimmer-Foundation , Grosshansdorf 22927 , Germany
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Wohak LE, Baranski AC, Krais AM, Schmeiser HH, Phillips DH, Arlt VM. The impact of p53 function on the metabolic activation of the carcinogenic air pollutant 3-nitrobenzanthrone and its metabolites 3-aminobenzanthrone and N-hydroxy-3-aminobenzanthrone in human cells. Mutagenesis 2018; 33:311-321. [PMID: 30215795 PMCID: PMC6180618 DOI: 10.1093/mutage/gey025] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 08/10/2018] [Accepted: 08/17/2018] [Indexed: 12/16/2022] Open
Abstract
The tumour suppressor p53, encoded by TP53, is a key player in a wide network of signalling pathways. We investigated its role in the bioactivation of the environmental carcinogen 3-nitrobenzanthrone (3-NBA)found in diesel exhaust and its metabolites 3-aminobenzanthrone (3-ABA) and N-hydroxy-3-aminobenzanthrone (N-OH-3-ABA) in a panel of isogenic human colorectal HCT116 cells differing only with respect to their TP53 status [i.e. TP53(+/+), TP53(+/-), TP53(-/-), TP53(R248W/+) or TP53(R248W/-)]. As a measure of metabolic competence, DNA adduct formation was determined using 32P-postlabelling. Wild-type (WT) p53 did not affect the bioactivation of 3-NBA; no difference in DNA adduct formation was observed in TP53(+/+), TP53(+/-) and TP53(-/-) cells. Bioactivation of both metabolites 3-ABA and N-OH-3-ABA on the other hand was WT-TP53 dependent. Lower 3-ABA- and N-OH-3-ABA-DNA adduct levels were found in TP53(+/-) and TP53(-/-) cells compared to TP53(+/+) cells, and p53's impact was attributed to differences in cytochrome P450 (CYP) 1A1 expression for 3-ABA whereas for N-OH-3-ABA, an impact of this tumour suppressor on sulphotransferase (SULT) 1A1/3 expression was detected. Mutant R248W-p53 protein function was similar to or exceeded the ability of WT-p53 in activating 3-NBA and its metabolites, measured as DNA adducts. However, identification of the xenobiotic-metabolising enzyme(s) (XMEs), through which mutant-p53 regulates these responses, proved difficult to decipher. For example, although both mutant cell lines exhibited higher CYP1A1 induction after 3-NBA treatment compared to TP53(+/+) cells, 3-NBA-derived DNA adduct levels were only higher in TP53(R248W/-) cells but not in TP53(R248W/+) cells. Our results show that p53's influence on carcinogen activation depends on the agent studied and thereby on the XMEs that mediate the bioactivation of that particular compound. The phenomenon of p53 regulating CYP1A1 expression in human cells is consistent with other recent findings; however, this is the first study highlighting the impact of p53 on sulphotransferase-mediated (i.e. SULT1A1) carcinogen metabolism in human cells.
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Affiliation(s)
- Laura E Wohak
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King’s College London, London, UK
- Section of Molecular Carcinogenesis, Institute of Cancer Research, Sutton, Surrey, UK
| | - Ann-Christin Baranski
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King’s College London, London, UK
| | - Annette M Krais
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King’s College London, London, UK
| | - Heinz H Schmeiser
- Division of Radiopharmaceutical Chemistry, German Cancer Research Center (DKFZ), Im Neuenheimer Feld, Heidelberg, Germany
| | - David H Phillips
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King’s College London, London, UK
- NIHR Health Protection Research Unit, Health Impact of Environmental Hazards, King’s College London, Public Health England and Imperial College London, London, UK
| | - Volker M Arlt
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King’s College London, London, UK
- NIHR Health Protection Research Unit, Health Impact of Environmental Hazards, King’s College London, Public Health England and Imperial College London, London, UK
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Stiborova M. Formation of Covalent DNA Adducts by Enzymatically Activated Carcinogens and Drugs In Vitro and Their Determination by 32P-postlabeling. J Vis Exp 2018. [PMID: 29630053 DOI: 10.3791/57177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Covalent DNA adducts formed by chemicals or drugs with carcinogenic potency are judged as one of the most important factors in the initiation phase of carcinogenic processes. This covalent binding, which is considered the cause of tumorigenesis, is now evaluated as a central dogma of chemical carcinogenesis. Here, methods are described employing the reactions catalyzed by cytochrome P450 and additional biotransformation enzymes to investigate the potency of chemicals or drugs for their activation to metabolites forming these DNA adducts. Procedures are presented describing the isolation of cellular fractions possessing biotransformation enzymes (microsomal and cytosolic samples with cytochromes P450 or other biotransformation enzymes, i.e., peroxidases, NADPH:cytochrome P450 oxidoreductase, NAD(P)H:quinone oxidoreductase, or xanthine oxidase). Furthermore, methods are described that can be used for the metabolic activation of analyzed chemicals by these enzymes as well as those for isolation of DNA. Further, the appropriate methods capable of detecting and quantifying chemical/drug-derived DNA adducts, i.e., different modifications of the 32P-postlabeling technique and employment of radioactive-labeled analyzed chemicals, are shown in detail.
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Linhart I, Hanzlíková I, Mráz J, Dušková Š. S-(3-Aminobenzanthron-2-yl)cysteine in the globin of rats as a novel type of adduct and possible biomarker of exposure to 3-nitrobenzanthrone, a potent environmental carcinogen. Arch Toxicol 2017; 91:3317-3325. [PMID: 28283705 DOI: 10.1007/s00204-017-1943-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 02/23/2017] [Indexed: 12/21/2022]
Abstract
3-Nitrobenzanthrone (3-NBA), a potent environmental mutagen and carcinogen, is known to be activated in vivo to 3-benzanthronylnitrenium ion which forms both NH and C2-bound adducts with DNA and also reacts with glutathione giving rise to urinary 3-aminobenzanthron-2-ylmercapturic acid. In this study, acid hydrolysate of globin from rats dosed intraperitoneally with 3-NBA was analysed by HPLC/MS to identify a novel type of cysteine adduct, 3-aminobenzanthron-2-ylcysteine (3-ABA-Cys), confirmed using a synthesised standard. The 3-ABA-Cys levels in globin peaked after single 3-NBA doses of 1 and 2 mg/kg on day 2 to attain 0.25 and 0.49 nmol/g globin, respectively, thereafter declining slowly to 70-80% of their maximum values during 15 days. After dosing rats for three consecutive days with 1 mg 3-NBA/kg a significant cumulation of 3-ABA-Cys in globin was observed. 3-ABA-Cys was also found in the plasma hydrolysate. Herein, after dosing with 1 and 2 mg 3-NBA/kg the adduct levels peaked on day 1 at 0.15 and 0.51 nmol/ml plasma, respectively, thereafter declining rapidly to undetectable levels on day 15. In addition, sulphinamide adducts were also found in the exposed rats, measured indirectly as 3-aminobenzanthrone (3-ABA) split off from globin by mild acid hydrolysis. Levels of both types of adducts in the globin samples parallelled very well with 3-ABA/3-ABA-Cys ratio being around 1:8. In conclusion, 3-ABA-Cys is the first example of arylnitrenium-cysteine adduct in globin representing a new promising class of biomarkers to assess cumulative exposures to aromatic amines, nitroaromatics and heteroaromatic amines.
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Affiliation(s)
- Igor Linhart
- Department of Organic Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology, Prague, Technická 5, 166 28, Prague, Czech Republic.
| | - Iveta Hanzlíková
- National Institute of Public Health, Prague, Šrobárova 48, 10042, Prague, Czech Republic
| | - Jaroslav Mráz
- National Institute of Public Health, Prague, Šrobárova 48, 10042, Prague, Czech Republic
| | - Šárka Dušková
- National Institute of Public Health, Prague, Šrobárova 48, 10042, Prague, Czech Republic
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7
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Krais AM, Speksnijder EN, Melis JPM, Indra R, Moserova M, Godschalk RW, van Schooten FJ, Seidel A, Kopka K, Schmeiser HH, Stiborova M, Phillips DH, Luijten M, Arlt VM. The impact of p53 on DNA damage and metabolic activation of the environmental carcinogen benzo[a]pyrene: effects in Trp53(+/+), Trp53(+/-) and Trp53(-/-) mice. Arch Toxicol 2016; 90:839-51. [PMID: 25995008 PMCID: PMC4785204 DOI: 10.1007/s00204-015-1531-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Accepted: 05/05/2015] [Indexed: 12/22/2022]
Abstract
The tumour suppressor p53 is one of the most important cancer genes. Previous findings have shown that p53 expression can influence DNA adduct formation of the environmental carcinogen benzo[a]pyrene (BaP) in human cells, indicating a role for p53 in the cytochrome P450 (CYP) 1A1-mediated biotransformation of BaP in vitro. We investigated the potential role of p53 in xenobiotic metabolism in vivo by treating Trp53(+/+), Trp53(+/-) and Trp53(-/-) mice with BaP. BaP-DNA adduct levels, as measured by (32)P-postlabelling analysis, were significantly higher in liver and kidney of Trp53(-/-) mice than of Trp53(+/+) mice. Complementarily, significantly higher amounts of BaP metabolites were also formed ex vivo in hepatic microsomes from BaP-pretreated Trp53(-/-) mice. Bypass of the need for metabolic activation by treating mice with BaP-7,8-dihydrodiol-9,10-epoxide resulted in similar adduct levels in liver and kidney in all mouse lines, confirming that the influence of p53 is on the biotransformation of the parent compound. Higher BaP-DNA adduct levels in the livers of Trp53(-/-) mice correlated with higher CYP1A protein levels and increased CYP1A enzyme activity in these animals. Our study demonstrates a role for p53 in the metabolism of BaP in vivo, confirming previous in vitro results on a novel role for p53 in CYP1A1-mediated BaP metabolism. However, our results also suggest that the mechanisms involved in the altered expression and activity of the CYP1A1 enzyme by p53 in vitro and in vivo are different.
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Affiliation(s)
- Annette M Krais
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment & Health, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, UK
| | - Ewoud N Speksnijder
- Center for Health Protection, National Institute for Public Health and the Environment (RIVM), 3721 MA, Bilthoven, The Netherlands
- Department of Human Genetics, Leiden University Medical Center, 2300 RC, Leiden, The Netherlands
| | - Joost P M Melis
- Center for Health Protection, National Institute for Public Health and the Environment (RIVM), 3721 MA, Bilthoven, The Netherlands
- Department of Human Genetics, Leiden University Medical Center, 2300 RC, Leiden, The Netherlands
| | - Radek Indra
- Department of Biochemistry, Faculty of Science, Charles University, 12840, Prague 2, Czech Republic
| | - Michaela Moserova
- Department of Biochemistry, Faculty of Science, Charles University, 12840, Prague 2, Czech Republic
| | - Roger W Godschalk
- Department of Toxicology, School for Nutrition, Toxicology and Metabolism (NUTRIM), Maastricht University Medical Centre, 6200 MD, Maastricht, The Netherlands
| | - Frederik-J van Schooten
- Department of Toxicology, School for Nutrition, Toxicology and Metabolism (NUTRIM), Maastricht University Medical Centre, 6200 MD, Maastricht, The Netherlands
| | - Albrecht Seidel
- Biochemical Institute for Environmental Carcinogens, Prof. Dr. Gernot Grimmer-Foundation, 22927, Grosshansdorf, Germany
| | - Klaus Kopka
- Division of Radiopharmaceutical Chemistry, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - Heinz H Schmeiser
- Division of Radiopharmaceutical Chemistry, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - Marie Stiborova
- Department of Biochemistry, Faculty of Science, Charles University, 12840, Prague 2, Czech Republic
| | - David H Phillips
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment & Health, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, UK
| | - Mirjam Luijten
- Center for Health Protection, National Institute for Public Health and the Environment (RIVM), 3721 MA, Bilthoven, The Netherlands
- Department of Human Genetics, Leiden University Medical Center, 2300 RC, Leiden, The Netherlands
| | - Volker M Arlt
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment & Health, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, UK.
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Dračínská H, Bárta F, Levová K, Hudecová A, Moserová M, Schmeiser HH, Kopka K, Frei E, Arlt VM, Stiborová M. Induction of cytochromes P450 1A1 and 1A2 suppresses formation of DNA adducts by carcinogenic aristolochic acid I in rats in vivo. Toxicology 2016; 344-346:7-18. [PMID: 26845733 PMCID: PMC4804751 DOI: 10.1016/j.tox.2016.01.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 01/21/2016] [Accepted: 01/29/2016] [Indexed: 02/05/2023]
Abstract
Aristolochic acid I (AAI) is a natural plant alkaloid causing aristolochic acid nephropathy, Balkan endemic nephropathy and their associated urothelial malignancies. One of the most efficient enzymes reductively activating AAI to species forming AAI-DNA adducts is cytosolic NAD(P)H quinone oxidoreductase 1. AAI is also either reductively activated or oxidatively detoxified to 8-hydroxyaristolochic acid (AAIa) by microsomal cytochrome P450 (CYP) 1A1 and 1A2. Here, we investigated which of these two opposing CYP1A1/2-catalyzed reactions prevails in AAI metabolism in vivo. The formation of AAI-DNA adducts was analyzed in liver, kidney and lung of rats treated with AAI, Sudan I, a potent inducer of CYP1A1/2, or AAI after pretreatment with Sudan I. Compared to rats treated with AAI alone, levels of AAI-DNA adducts determined by the (32)P-postlabeling method were lower in liver, kidney and lung of rats treated with AAI after Sudan I. The induction of CYP1A1/2 by Sudan I increased AAI detoxification to its O-demethylated metabolite AAIa, thereby reducing the actual amount of AAI available for reductive activation. This subsequently resulted in lower AAI-DNA adduct levels in the rat in vivo. Our results demonstrate that CYP1A1/2-mediated oxidative detoxification of AAI is the predominant role of these enzymes in rats in vivo, thereby suppressing levels of AAI-DNA adducts.
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Affiliation(s)
- Helena Dračínská
- Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - František Bárta
- Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Kateřina Levová
- Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Alena Hudecová
- Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Michaela Moserová
- Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Heinz H Schmeiser
- Division of Radiopharmaceutical Chemistry, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Klaus Kopka
- Division of Radiopharmaceutical Chemistry, German Cancer Research Center (DKFZ), Heidelberg, Germany; German Cancer Consortium (DKTK), Heidelberg, Germany
| | - Eva Frei
- Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Volker M Arlt
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment & Health, King's College London, London, United Kingdom
| | - Marie Stiborová
- Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague, Czech Republic.
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Tebay LE, Robertson H, Durant ST, Vitale SR, Penning TM, Dinkova-Kostova AT, Hayes JD. Mechanisms of activation of the transcription factor Nrf2 by redox stressors, nutrient cues, and energy status and the pathways through which it attenuates degenerative disease. Free Radic Biol Med 2015; 88:108-146. [PMID: 26122708 PMCID: PMC4659505 DOI: 10.1016/j.freeradbiomed.2015.06.021] [Citation(s) in RCA: 604] [Impact Index Per Article: 67.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 06/09/2015] [Accepted: 06/10/2015] [Indexed: 12/11/2022]
Abstract
UNLABELLED Nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) regulates the basal and stress-inducible expression of a battery of genes encoding key components of the glutathione-based and thioredoxin-based antioxidant systems, as well as aldo-keto reductase, glutathione S-transferase, and NAD(P)H quinone oxidoreductase-1 drug-metabolizing isoenzymes along with multidrug-resistance-associated efflux pumps. It therefore plays a pivotal role in both intrinsic resistance and cellular adaptation to reactive oxygen species (ROS) and xenobiotics. Activation of Nrf2 can, however, serve as a double-edged sword because some of the genes it induces may contribute to chemical carcinogenesis by promoting futile redox cycling of polycyclic aromatic hydrocarbon metabolites or confer resistance to chemotherapeutic drugs by increasing the expression of efflux pumps, suggesting its cytoprotective effects will vary in a context-specific fashion. In addition to cytoprotection, Nrf2 also controls genes involved in intermediary metabolism, positively regulating those involved in NADPH generation, purine biosynthesis, and the β-oxidation of fatty acids, while suppressing those involved in lipogenesis and gluconeogenesis. Nrf2 is subject to regulation at multiple levels. Its ability to orchestrate adaptation to oxidants and electrophiles is due principally to stress-stimulated modification of thiols within one of its repressors, the Kelch-like ECH-associated protein 1 (Keap1), which is present in the cullin-3 RING ubiquitin ligase (CRL) complex CRLKeap1. Thus modification of Cys residues in Keap1 blocks CRLKeap1 activity, allowing newly translated Nrf2 to accumulate rapidly and induce its target genes. The ability of Keap1 to repress Nrf2 can be attenuated by p62/sequestosome-1 in a mechanistic target of rapamycin complex 1 (mTORC1)-dependent manner, thereby allowing refeeding after fasting to increase Nrf2-target gene expression. In parallel with repression by Keap1, Nrf2 is also repressed by β-transducin repeat-containing protein (β-TrCP), present in the Skp1-cullin-1-F-box protein (SCF) ubiquitin ligase complex SCFβ-TrCP. The ability of SCFβ-TrCP to suppress Nrf2 activity is itself enhanced by prior phosphorylation of the transcription factor by glycogen synthase kinase-3 (GSK-3) through formation of a DSGIS-containing phosphodegron. However, formation of the phosphodegron in Nrf2 by GSK-3 is inhibited by stimuli that activate protein kinase B (PKB)/Akt. In particular, PKB/Akt activity can be increased by phosphoinositide 3-kinase and mTORC2, thereby providing an explanation of why antioxidant-responsive element-driven genes are induced by growth factors and nutrients. Thus Nrf2 activity is tightly controlled via CRLKeap1 and SCFβ-TrCP by oxidative stress and energy-based signals, allowing it to mediate adaptive responses that restore redox homeostasis and modulate intermediary metabolism. Based on the fact that Nrf2 influences multiple biochemical pathways in both positive and negative ways, it is likely its dose-response curve, in terms of susceptibility to certain degenerative disease, is U-shaped. Specifically, too little Nrf2 activity will lead to loss of cytoprotection, diminished antioxidant capacity, and lowered β-oxidation of fatty acids, while conversely also exhibiting heightened sensitivity to ROS-based signaling that involves receptor tyrosine kinases and apoptosis signal-regulating kinase-1. By contrast, too much Nrf2 activity disturbs the homeostatic balance in favor of reduction, and so may have deleterious consequences including overproduction of reduced glutathione and NADPH, the blunting of ROS-based signal transduction, epithelial cell hyperplasia, and failure of certain cell types to differentiate correctly. We discuss the basis of a putative U-shaped Nrf2 dose-response curve in terms of potentially competing processes relevant to different stages of tumorigenesis.
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Affiliation(s)
- Lauren E Tebay
- Jacqui Wood Cancer Centre, Division of Cancer Research, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, Scotland, UK
| | - Holly Robertson
- Jacqui Wood Cancer Centre, Division of Cancer Research, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, Scotland, UK
| | - Stephen T Durant
- AstraZeneca Oncology Innovative Medicines, Bioscience, 33F197 Mereside, Alderley Park, Cheshire SK10 4TG, UK
| | - Steven R Vitale
- Center of Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104-6160, USA
| | - Trevor M Penning
- Center of Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104-6160, USA
| | - Albena T Dinkova-Kostova
- Jacqui Wood Cancer Centre, Division of Cancer Research, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, Scotland, UK
| | - John D Hayes
- Jacqui Wood Cancer Centre, Division of Cancer Research, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, Scotland, UK.
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Arlt VM, Krais AM, Godschalk RW, Riffo-Vasquez Y, Mrizova I, Roufosse CA, Corbin C, Shi Q, Frei E, Stiborova M, van Schooten FJ, Phillips DH, Spina D. Pulmonary Inflammation Impacts on CYP1A1-Mediated Respiratory Tract DNA Damage Induced by the Carcinogenic Air Pollutant Benzo[a]pyrene. Toxicol Sci 2015; 146:213-25. [PMID: 25911668 PMCID: PMC4517052 DOI: 10.1093/toxsci/kfv086] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Pulmonary inflammation can contribute to the development of lung cancer in humans. We investigated whether pulmonary inflammation alters the genotoxicity of polycyclic aromatic hydrocarbons (PAHs) in the lungs of mice and what mechanisms are involved. To model nonallergic acute inflammation, mice were exposed intranasally to lipopolysaccharide (LPS; 20 µg/mouse) and then instilled intratracheally with benzo[a]pyrene (BaP; 0.5 mg/mouse). BaP-DNA adduct levels, measured by (32)P-postlabeling analysis, were approximately 3-fold higher in the lungs of LPS/BaP-treated mice than in mice treated with BaP alone. Pulmonary Cyp1a1 enzyme activity was decreased in LPS/BaP-treated mice relative to BaP-treated mice suggesting that pulmonary inflammation impacted on BaP-induced Cyp1a1 activity in the lung. Our results showed that Cyp1a1 appears to be important for BaP detoxification in vivo and that the decrease of pulmonary Cyp1a1 activity in LPS/BaP-treated mice results in a decrease of pulmonary BaP detoxification, thereby enhancing BaP genotoxicity (ie, DNA adduct formation) in the lung. Because less BaP was detoxified by Cyp1a1 in the lungs of LPS/BaP-treated mice, more BaP circulated via the blood to extrapulmonary tissues relative to mice treated with BaP only. Indeed, we observed higher BaP-DNA adduct levels in livers of LPS/BaP-treated mice compared with BaP-treated mice. Our results indicate that pulmonary inflammation could be a critical determinant in the induction of genotoxicity in the lung by PAHs like BaP. Cyp1a1 appears to be involved in both BaP bioactivation and detoxification although the contribution of other enzymes to BaP-DNA adduct formation in lung and liver under inflammatory conditions remains to be explored.
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Affiliation(s)
- Volker M Arlt
- *Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment & Health, King's College London, London SE1 9NH, United Kingdom,
| | - Annette M Krais
- *Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment & Health, King's College London, London SE1 9NH, United Kingdom
| | - Roger W Godschalk
- Department of Toxicology, School for Nutrition, Toxicology and Metabolism (NUTRIM), Maastricht University Medical Centre, 6200 MD Maastricht, The Netherlands
| | - Yanira Riffo-Vasquez
- Sackler Institute of Pulmonary Pharmacology, Institute of Pharmaceutical Science, King's College London, London SE1 9NH, United Kingdom
| | - Iveta Mrizova
- Department of Biochemistry, Faculty of Science, Charles University, 12840 Prague 2, Czech Republic
| | - Candice A Roufosse
- Department of Histopathology, Imperial College Healthcare NHS Trust, Hammersmith Hospital, London W12 0HS, United Kingdom, and
| | - Charmaine Corbin
- *Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment & Health, King's College London, London SE1 9NH, United Kingdom
| | - Quan Shi
- Department of Toxicology, School for Nutrition, Toxicology and Metabolism (NUTRIM), Maastricht University Medical Centre, 6200 MD Maastricht, The Netherlands
| | - Eva Frei
- Division of Preventive Oncology, National Center for Tumor Diseases, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Marie Stiborova
- Department of Biochemistry, Faculty of Science, Charles University, 12840 Prague 2, Czech Republic
| | - Frederik-Jan van Schooten
- Department of Toxicology, School for Nutrition, Toxicology and Metabolism (NUTRIM), Maastricht University Medical Centre, 6200 MD Maastricht, The Netherlands
| | - David H Phillips
- *Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment & Health, King's College London, London SE1 9NH, United Kingdom
| | - Domenico Spina
- Sackler Institute of Pulmonary Pharmacology, Institute of Pharmaceutical Science, King's College London, London SE1 9NH, United Kingdom
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11
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Krais AM, Mühlbauer KR, Kucab JE, Chinbuah H, Cornelius MG, Wei QX, Hollstein M, Phillips DH, Arlt VM, Schmeiser HH. Comparison of the metabolic activation of environmental carcinogens in mouse embryonic stem cells and mouse embryonic fibroblasts. Toxicol In Vitro 2015; 29:34-43. [PMID: 25230394 PMCID: PMC4258613 DOI: 10.1016/j.tiv.2014.09.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 08/31/2014] [Accepted: 09/05/2014] [Indexed: 01/08/2023]
Abstract
We compared mouse embryonic stem (ES) cells and fibroblasts (MEFs) for their ability to metabolically activate the environmental carcinogens benzo[a]pyrene (BaP), 3-nitrobenzanthrone (3-NBA) and aristolochic acid I (AAI), measuring DNA adduct formation by (32)P-postlabelling and expression of xenobiotic-metabolism genes by quantitative real-time PCR. At 2 μM, BaP induced Cyp1a1 expression in MEFs to a much greater extent than in ES cells and formed 45 times more adducts. Nqo1 mRNA expression was increased by 3-NBA in both cell types but induction was higher in MEFs, as was adduct formation. For AAI, DNA binding was over 450 times higher in MEFs than in ES cells, although Nqo1 and Cyp1a1 transcriptional levels did not explain this difference. We found higher global methylation of DNA in ES cells than in MEFs, which suggests higher chromatin density and lower accessibility of the DNA to DNA damaging agents in ES cells. However, AAI treatment did not alter DNA methylation. Thus mouse ES cells and MEFs have the metabolic competence to activate a number of environmental carcinogens, but MEFs have lower global DNA methylation and higher metabolic capacity than mouse ES cells.
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Affiliation(s)
- Annette M Krais
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom
| | - Karl-Rudolf Mühlbauer
- Research Group Genetic Alterations in Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Jill E Kucab
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom
| | - Helena Chinbuah
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom
| | - Michael G Cornelius
- Research Group Genetic Alterations in Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Quan-Xiang Wei
- Research Group Genetic Alterations in Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Monica Hollstein
- Research Group Genetic Alterations in Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, Germany; Molecular Mechanisms and Biomarkers Group, International Agency for Research on Cancer, Lyon, France
| | - David H Phillips
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom
| | - Volker M Arlt
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom
| | - Heinz H Schmeiser
- Research Group Genetic Alterations in Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, Germany
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12
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Arlt VM, Henderson CJ, Wolf CR, Stiborová M, Phillips DH. The Hepatic Reductase Null (HRN™) and Reductase Conditional Null (RCN) mouse models as suitable tools to study metabolism, toxicity and carcinogenicity of environmental pollutants. Toxicol Res (Camb) 2015. [DOI: 10.1039/c4tx00116h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
This review describes the applicability of the Hepatic Reductase Null (HRN) and Reductase Conditional Null (RCN) mouse models to study carcinogen metabolism.
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Affiliation(s)
- Volker M. Arlt
- Analytical and Environmental Sciences Division
- MRC-PHE Centre for Environment and Health
- King's College London
- London SE1 9NH
- UK
| | - Colin J. Henderson
- Division of Cancer Research
- Medical Research Institute
- Jacqui Wood Cancer Centre
- University of Dundee
- Dundee DD1 9SY
| | - C. Roland Wolf
- Division of Cancer Research
- Medical Research Institute
- Jacqui Wood Cancer Centre
- University of Dundee
- Dundee DD1 9SY
| | - Marie Stiborová
- Department of Biochemistry
- Faculty of Science
- Charles University
- 128 40 Prague 2
- Czech Republic
| | - David H. Phillips
- Analytical and Environmental Sciences Division
- MRC-PHE Centre for Environment and Health
- King's College London
- London SE1 9NH
- UK
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13
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Stiborová M, Bárta F, Levová K, Hodek P, Frei E, Arlt VM, Schmeiser HH. The influence of ochratoxin A on DNA adduct formation by the carcinogen aristolochic acid in rats. Arch Toxicol 2014; 89:2141-58. [PMID: 25209566 DOI: 10.1007/s00204-014-1360-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 08/28/2014] [Indexed: 11/28/2022]
Abstract
UNLABELLED Exposure to the plant nephrotoxin and carcinogen aristolochic acid (AA) leads to the development of AA nephropathy, Balkan endemic nephropathy (BEN) and upper urothelial carcinoma (UUC) in humans. Beside AA, exposure to ochratoxin A (OTA) was linked to BEN. Although OTA was rejected as a factor for BEN/UUC, there is still no information whether the development of AA-induced BEN/UUC is influenced by OTA exposure. Therefore, we studied the influence of OTA on the genotoxicity of AA (AA-DNA adduct formation) in vivo. AA-DNA adducts were formed in liver and kidney of rats treated with AA or AA combined with OTA, but no OTA-related DNA adducts were detectable in rats treated with OTA alone or OTA combined with AA. Compared to rats treated with AA alone, AA-DNA adduct levels were 5.4- and 1.6-fold higher in liver and kidney, respectively, of rats treated with AA combined with OTA. Although AA and OTA induced NAD(P)H quinone oxidoreductase (NQO1) activating AA to DNA adducts, their combined treatment did not lead to either higher NQO1 enzyme activity or higher AA-DNA adduct levels in ex vivo incubations. Oxidation of AA I (8-methoxy-6-nitrophenanthro[3,4-d]-1,3-dioxole-5-carboxylic acid) to its detoxification metabolite, 8-hydroxyaristolochic acid, was lower in microsomes from rats treated with AA and OTA, and this was paralleled by lower activities of cytochromes P450 1A1/2 and/or 2C11 in these microsomes. Our results indicate that a decrease in AA detoxification after combined exposure to AA and OTA leads to an increase in AA-DNA adduct formation in liver and kidney of rats.
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Affiliation(s)
- Marie Stiborová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40, Prague 2, Czech Republic.
| | - František Bárta
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40, Prague 2, Czech Republic
| | - Kateřina Levová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40, Prague 2, Czech Republic
| | - Petr Hodek
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40, Prague 2, Czech Republic
| | - Eva Frei
- Division of Preventive Oncology, National Center for Tumor Diseases, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - Volker M Arlt
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environmental and Health, King's College London, 150 Stamford Street, London, SE1 9NH, UK
| | - Heinz H Schmeiser
- Division of Radiopharmaceutical Chemistry (E030), German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
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14
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Bárta F, Levová K, Frei E, Schmeiser HH, Arlt VM, Stiborová M. The effect of aristolochic acid I on expression of NAD(P)H:quinone oxidoreductase in mice and rats--a comparative study. MUTATION RESEARCH. GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2014; 768:1-7. [PMID: 24769487 DOI: 10.1016/j.mrgentox.2014.01.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 12/22/2013] [Accepted: 01/15/2014] [Indexed: 10/25/2022]
Abstract
Aristolochic acid is the cause of aristolochic acid nephropathy (AAN) and Balkan endemic nephropathy (BEN) and their associated urothelial malignancies. Using Western blotting, we investigated the expression of NAD(P)H quinone oxidoreductase (NQO1), the most efficient cytosolic enzyme that reductively activates aristolochic acid I (AAI) in mice and rats. In addition, the effect of AAI on the expression of the NQO1 protein and its enzymatic activity in these experimental animal models was examined. We found that NQO1 protein levels in cytosolic fractions isolated from liver, kidney and lung of mice differed from those expressed in these organs of rats. In mice, the highest levels of NQO1 protein and NQO1 activity were found in the kidney, followed by lung and liver. In contrast, the NQO1 protein levels and enzyme activity were lowest in rat-kidney cytosol, whereas the highest amounts of NQO1 protein and activity were found in lung cytosols, followed by those of liver. NQO1 protein and enzyme activity were induced in liver and kidney of AAI-pretreated mice compared with those of untreated mice. NQO1 protein and enzyme activity were also induced in rat kidney by AAI. Furthermore, the increase in hepatic and renal NQO1 enzyme activity was associated with AAI bio-activation and elevated AAI-DNA adduct levels were found in ex vivo incubations of cytosolic fractions with DNA and AAI. In conclusion, our results indicate that AAI can increase its own metabolic activation by inducing NQO1, thereby enhancing its own genotoxic potential.
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Affiliation(s)
- František Bárta
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
| | - Kateřina Levová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
| | - Eva Frei
- Division of Preventive Oncology, National Center for Tumour Diseases, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Heinz H Schmeiser
- Research Group Genetic Alteration in Carcinogenesis, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Volker M Arlt
- Analytical and Environmental Sciences Division, King's College London, MRC-PHE Centre for Environmental & Health, 150 Stamford Street, London SE1 9NH, United Kingdom
| | - Marie Stiborová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic.
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15
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Stiborová M, Frei E, Schmeiser HH, Arlt VM, Martínek V. Mechanisms of enzyme-catalyzed reduction of two carcinogenic nitro-aromatics, 3-nitrobenzanthrone and aristolochic acid I: Experimental and theoretical approaches. Int J Mol Sci 2014; 15:10271-95. [PMID: 24918288 PMCID: PMC4100152 DOI: 10.3390/ijms150610271] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 05/30/2014] [Accepted: 05/30/2014] [Indexed: 01/14/2023] Open
Abstract
This review summarizes the results found in studies investigating the enzymatic activation of two genotoxic nitro-aromatics, an environmental pollutant and carcinogen 3-nitrobenzanthrone (3-NBA) and a natural plant nephrotoxin and carcinogen aristolochic acid I (AAI), to reactive species forming covalent DNA adducts. Experimental and theoretical approaches determined the reasons why human NAD(P)H quinone oxidoreductase (NQO1) and cytochromes P450 (CYP) 1A1 and 1A2 have the potential to reductively activate both nitro-aromatics. The results also contributed to the elucidation of the molecular mechanisms of these reactions. The contribution of conjugation enzymes such as N,O-acetyltransferases (NATs) and sulfotransferases (SULTs) to the activation of 3-NBA and AAI was also examined. The results indicated differences in the abilities of 3-NBA and AAI metabolites to be further activated by these conjugation enzymes. The formation of DNA adducts generated by both carcinogens during their reductive activation by the NOQ1 and CYP1A1/2 enzymes was investigated with pure enzymes, enzymes present in subcellular cytosolic and microsomal fractions, selective inhibitors, and animal models (including knock-out and humanized animals). For the theoretical approaches, flexible in silico docking methods as well as ab initio calculations were employed. The results summarized in this review demonstrate that a combination of experimental and theoretical approaches is a useful tool to study the enzyme-mediated reaction mechanisms of 3-NBA and AAI reduction.
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Affiliation(s)
- Marie Stiborová
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, CZ-12843, Prague 2, Czech Republic.
| | - Eva Frei
- Division of Preventive Oncology, National Center for Tumor Diseases, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
| | - Heinz H Schmeiser
- Radiopharmaceutical Chemistry E030, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
| | - Volker M Arlt
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environmental & Health, King's College London, 150 Stamford Street, London SE1 9NH, UK.
| | - Václav Martínek
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, CZ-12843, Prague 2, Czech Republic.
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16
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Stiborová M, Levová K, Bárta F, Šulc M, Frei E, Arlt VM, Schmeiser HH. The influence of dicoumarol on the bioactivation of the carcinogen aristolochic acid I in rats. Mutagenesis 2014; 29:189-200. [PMID: 24598128 DOI: 10.1093/mutage/geu004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Aristolochic acid I (AAI) is the major toxic component of the plant extract AA, which leads to the development of nephropathy and urothelial cancer in human. Individual susceptibility to AAI-induced disease might reflect variability in enzymes that metabolise AAI. In vitro NAD(P)H quinone oxidoreductase (NQO1) is the most potent enzyme that activates AAI by catalyzing formation of AAI-DNA adducts, which are found in kidneys of patients exposed to AAI. Inhibition of renal NQO1 activity by dicoumarol has been shown in mice. Here, we studied the influence of dicoumarol on metabolic activation of AAI in Wistar rats in vivo. In contrast to previous in vitro findings, dicoumarol did not inhibit AAI-DNA adduct formation in rats. Compared with rats treated with AAI alone, 11- and 5.4-fold higher AAI-DNA adduct levels were detected in liver and kidney, respectively, of rats pretreated with dicoumarol prior to exposure to AAI. Cytosols and microsomes isolated from liver and kidney of these rats were analysed for activity and protein levels of enzymes known to be involved in AAI metabolism. The combination of dicoumarol with AAI induced NQO1 protein level and activity in both organs. This was paralleled by an increase in AAI-DNA adduct levels found in ex vivo incubations with cytosols from rats pretreated with dicoumarol compared to cytosols from untreated rats. Microsomal ex vivo incubations showed a lower AAI detoxication to its oxidative metabolite, 8-hydroxyaristolochic acid (AAIa), although cytochrome P450 (CYP) 1A was practically unchanged. Because of these unexpected results, we examined CYP2C activity in microsomes and found that treatment of rats with dicoumarol alone and in combination with AAI inhibited CYP2C6/11 in liver. Therefore, these results indicate that CYP2C enzymes might contribute to AAI detoxication.
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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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Hodek P, Koblihová J, Kizek R, Frei E, Arlt VM, Stiborová M. The relationship between DNA adduct formation by benzo[a]pyrene and expression of its activation enzyme cytochrome P450 1A1 in rat. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2013; 36:989-96. [PMID: 24095716 DOI: 10.1016/j.etap.2013.09.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 09/04/2013] [Accepted: 09/05/2013] [Indexed: 06/02/2023]
Abstract
Benzo[a]pyrene (BaP) is a human carcinogen requiring metabolic activation prior to reaction with DNA. Cytochrome P450 (CYP) 1A1 is the most important hepatic and intestinal enzyme in both BaP activation and detoxification. CYP1A2 is also capable of oxidizing BaP, but to a lesser extent. The induction of CYP1A1/2 by BaP and/or β-naphthoflavone in liver and small intestine of rats was investigated. Both BaP and β-naphthoflavone induced CYP1A expression and increased enzyme activities in both organs. Moreover, the induction of CYP1A enzyme activities resulted in an increase in formation of BaP-DNA adducts detected by (32)P-postlabeling in rat liver and in the distal part of small intestine in vivo. The increases in CYP1A enzyme activity were also associated with bioactivation of BaP and elevated BaP-DNA adduct levels in ex vivo incubations of microsomes of both organs with DNA and BaP. These findings indicate a stimulating effect of both compounds on BaP-induced carcinogenesis.
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Affiliation(s)
- Petr Hodek
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
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18
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Stiborová M, Dračínská H, Martínek V, Svášková D, Hodek P, Milichovský J, Hejduková Ž, Brotánek J, Schmeiser HH, Frei E. Induced expression of cytochrome P450 1A and NAD(P)H:quinone oxidoreductase determined at mRNA, protein, and enzyme activity levels in rats exposed to the carcinogenic azo dye 1-phenylazo-2-naphthol (Sudan I). Chem Res Toxicol 2013; 26:290-9. [PMID: 23289503 DOI: 10.1021/tx3004533] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Sudan I (1-phenylazo-2-hydroxynaphthol) is a suspected human carcinogen causing tumors in the livers and urinary bladders of rats, mice, and rabbits. Here, we investigated for the first time the influence of Sudan I exposure on the expression of several biotransformation enzymes in the livers, kidneys, and lungs of rats concomitantly at the mRNA and protein levels and assayed their enzymatic activities. We also studied its effect on the formation of Sudan I-derived DNA adducts in vitro. Sudan I increased the total amounts of cytochrome P450 (P450) in all organs tested. Western blots using antibodies raised against various P450s, NADPH:P450 reductase, and NAD(P)H:quinone oxidoreductase 1 (NQO1) showed that the expression of P450 1A1 and NQO1 was induced in the liver, kidney, and lung of rats treated with Sudan I. The higher protein levels correlated with increased enzyme activities of P450 1A1/2 and NQO1. Furthermore, 9.9-, 5.9-, and 2.8-fold increases in the formation of Sudan I oxidative metabolites catalyzed by microsomes isolated from the liver, kidney, and lung, respectively, of rats treated with Sudan I were found. The relative amounts of P450 1A and NQO1 mRNA, measured by real-time polymerase chain reaction (RT-PCR) analysis, demonstrated that Sudan I induced the expression of P450 1A1 and NQO1 mRNA in the liver, kidney, and lung, and of P450 1A2 mRNA in kidney and lung. Finally, microsomes isolated from livers, kidneys, and lungs of Sudan I exposed rats more effectively catalyzed the formation of Sudan I-DNA adducts than microsomes from organs of control rats. This was attributable to the higher P450 1A1 expression. Because P450 1A1 is playing a major role in the bioactivation of Sudan I in rat and human systems, its induction by Sudan I may have a profound effect on cancer risk by this azo dye. In addition, the induction of P450 1A1/2 and NQO1 enzymes can influence individual human susceptibility to other environmental carcinogens and have an effect on cancer risk.
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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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19
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Levova K, Moserova M, Nebert DW, Phillips DH, Frei E, Schmeiser HH, Arlt VM, Stiborova M. NAD(P)H:quinone oxidoreductase expression in Cyp1a-knockout and CYP1A-humanized mouse lines and its effect on bioactivation of the carcinogen aristolochic acid I. Toxicol Appl Pharmacol 2012; 265:360-7. [PMID: 22982977 DOI: 10.1016/j.taap.2012.09.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 09/05/2012] [Accepted: 09/06/2012] [Indexed: 01/01/2023]
Abstract
Aristolochic acid causes a specific nephropathy (AAN), Balkan endemic nephropathy, and urothelial malignancies. Using Western blotting suitable to determine protein expression, we investigated in several transgenic mouse lines expression of NAD(P)H:quinone oxidoreductase (NQO1)-the most efficient cytosolic enzyme that reductively activates aristolochic acid I (AAI). The mouse tissues used were from previous studies [Arlt et al., Chem. Res. Toxicol. 24 (2011) 1710; Stiborova et al., Toxicol. Sci. 125 (2012) 345], in which the role of microsomal cytochrome P450 (CYP) enzymes in AAI metabolism in vivo had been determined. We found that NQO1 levels in liver, kidney and lung of Cyp1a1⁻/⁻, Cyp1a2⁻/⁻ and Cyp1a1/1a2⁻/⁻ knockout mouse lines, as well as in two CYP1A-humanized mouse lines harboring functional human CYP1A1 and CYP1A2 and lacking the mouse Cyp1a1/1a2 orthologs, differed from NQO1 levels in wild-type mice. NQO1 protein and enzymic activity were induced in hepatic and renal cytosolic fractions isolated from AAI-pretreated mice, compared with those in untreated mice. Furthermore, this increase in hepatic NQO1 enzyme activity was associated with bioactivation of AAI and elevated AAI-DNA adduct levels in ex vivo incubations of cytosolic fractions with DNA and AAI. In conclusion, AAI appears to increase its own metabolic activation by inducing NQO1, thereby enhancing its own genotoxic potential.
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Affiliation(s)
- Katerina Levova
- Department of Biochemistry, Faculty of Science, Charles University, Prague, Czech Republic
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Oeder S, Jörres RA, Weichenmeier I, Pusch G, Schober W, Pfab F, Behrendt H, Schierl R, Kronseder A, Nowak D, Dietrich S, Fernández-Caldas E, Lintelmann J, Zimmermann R, Lang R, Mages J, Fromme H, Buters JTM. Airborne Indoor Particles from Schools Are More Toxic than Outdoor Particles. Am J Respir Cell Mol Biol 2012; 47:575-82. [DOI: 10.1165/rcmb.2012-0139oc] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Linhart I, Mráz J, Hanzlíková I, Silhánková A, Frantík E, Himl M. Carcinogenic 3-nitrobenzanthrone but not 2-nitrobenzanthrone is metabolised to an unusual mercapturic acid in rats. Toxicol Lett 2011; 208:246-53. [PMID: 22143054 DOI: 10.1016/j.toxlet.2011.11.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Revised: 11/18/2011] [Accepted: 11/19/2011] [Indexed: 11/19/2022]
Abstract
3-Nitrobenzanthrone (3-NBA) is an extremely potent mutagen and suspect human carcinogen found in diesel exhaust. Its isomer 2-nitrobenzanthrone (2-NBA) has also been found in ambient air. These isomers differ in mutagenicity in Salmonella by 2-3 orders of magnitude. To identify their urinary metabolites and also to assess the assumed differences in their excretion, rats were dosed orally with 2mg/kg b.w. of either 2-NBA or 3-NBA. Their urine was collected for two consecutive days after dosage. Both LC-ESI-MS and GC-MS confirmed formation of the corresponding aminobenzanthrones (ABA). Excretion of these metabolites within the first day after dosing with 2- and 3-ABA amounted to 0.32±0.06 and 0.83±0.40% of the doses, respectively, while the excretion within the second day was by one order of magnitude lower. A novel mercapturic acid metabolite of 3-NBA was identified in urine by LC-ESI-MS as N-acetyl-S-(3-aminobenzanthron-2-yl)cysteine (3-ABA-MA) by comparison with the authentic standard. Its excretion amounted to 0.49±0.15 and 0.02±0.01% of dose within the first and second day after dosing, respectively. In contrast, no mercapturic acid was detected in the urine of rats dosed with 2-NBA. Observed difference in the mercapturic acid formation between 2- and 3-NBA is a new distinctive feature reflecting differences in the critical step of their metabolism, i.e., benzanthronylnitrenium ion formation that is intrinsically associated with biological activities of these two isomers. Moreover, 3-ABA-MA is a promising candidate biomarker of exposure to the carcinogenic 3-NBA.
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Affiliation(s)
- Igor Linhart
- Department of Organic Chemistry, Faculty of Chemical Technology, Institute of Chemical Technology, Prague, Technická 1905, CZ-166 28 Prague, Czech Republic.
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Rat cytochromes P450 oxidize 3-aminobenzanthrone, a human metabolite of the carcinogenic environmental pollutant 3-nitrobenzanthrone. Interdiscip Toxicol 2011; 1:150-4. [PMID: 21218105 PMCID: PMC2993481 DOI: 10.2478/v10102-010-0031-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Revised: 08/11/2008] [Accepted: 08/25/2008] [Indexed: 11/20/2022] Open
Abstract
3-Aminobenzanthrone (3-ABA) is a human metabolite of carcinogenic 3-nitrobenzanthrone (3-NBA), which occurs in diesel exhaust and air pollution. Understanding which cytochrome P450 (CYP) enzymes are involved in metabolic activation and/or detoxication of this toxicant is important in the assessment of an individual's susceptibility to this substance. The aim of this study was to evaluate the efficiency of rat hepatic CYPs to oxidize 3-ABA and to examine the metabolites formed during such an oxidation. The metabolites formed by CYPs in rat hepatic microsomes were separated by high performance liquid chromatography (HPLC). 3-ABA is oxidized by these enzymes to three metabolites, which were separated by HPLC as distinguish product peaks. Using co-chromatography with synthetic standards, two of them were identified to be oxidative metabolites of 3-ABA, N-hydroxy-3-ABA and 3-NBA. The structure of another 3-ABA metabolite remains to be characterized. To define the role of rat hepatic CYP enzymes in metabolism of 3-ABA, we investigated the modulation of its oxidation using different inducers of CYPs for treatment of rats to enrich the liver microsomes with individual CYPs. Based on these studies, we attribute most of 3-ABA oxidation in rat hepatic microsomes to CYP2B, followed by CYP1A, although a role of other hepatic CYPs cannot be ruled out. Inhibition of 3-ABA oxidation by selective inhibitors of individual CYPs, supported this finding.
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Levová K, Moserová M, Kotrbová V, Šulc M, Henderson CJ, Wolf CR, Phillips DH, Frei E, Schmeiser HH, Mareš J, Arlt VM, Stiborová M. Role of Cytochromes P450 1A1/2 in Detoxication and Activation of Carcinogenic Aristolochic Acid I: Studies with the Hepatic NADPH:Cytochrome P450 Reductase Null (HRN) Mouse Model. Toxicol Sci 2011; 121:43-56. [DOI: 10.1093/toxsci/kfr050] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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Mizerovská J, Dračínská H, Frei E, Schmeiser HH, Arlt VM, Stiborová M. Induction of biotransformation enzymes by the carcinogenic air-pollutant 3-nitrobenzanthrone in liver, kidney and lung, after intra-tracheal instillation in rats. Mutat Res 2010; 720:34-41. [PMID: 21167309 DOI: 10.1016/j.mrgentox.2010.12.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 11/12/2010] [Accepted: 12/02/2010] [Indexed: 10/18/2022]
Abstract
3-Nitrobenzanthrone (3-NBA), a carcinogenic air pollutant, was investigated for its ability to induce cytochrome P450 (CYP) 1A1/2 and NAD(P)H:quinone oxidoreductase (NQO1) in liver, kidney and lung of rats treated by intra-tracheal instillation. The organs used were from a previous study performed to determine the persistence of 3-NBA-derived DNA adducts in target and non-target tissues (Bieler et al., Carcinogenesis 28 (2007) 1117-1121, [22]). NQO1 is the enzyme reducing 3-NBA to N-hydroxy-3-aminobenzanthrone (N-OH-3-ABA) and CYP1A enzymes oxidize a human metabolite of 3-NBA, 3-aminobenzanthrone (3-ABA), to yield the same reactive intermediate. 3-NBA and 3-ABA are both activated to species forming DNA adducts by cytosols and/or microsomes isolated from rat lung, the target organ for 3-NBA carcinogenicity, and from liver and kidney. Each compound generated the same five DNA adducts detectable by (32)P-postlabelling. When hepatic cytosols from rats treated with 0.2 or 2mg/kg body weight of 3-NBA were incubated with 3-NBA, DNA adduct formation was 3.2- and 8.6-fold higher, respectively, than in incubations with cytosols from control animals. Likewise, cytosols isolated from lungs and kidneys of rats exposed to 3-NBA more efficiently activated 3-NBA than those of control rats. This increase corresponded to an increase in protein levels and enzymatic activities of NQO1. Incubations of hepatic, pulmonary or renal microsomes of 3-NBA-treated rats with 3-ABA led to an 9.6-fold increase in DNA-adduct formation relative to controls. The highest induction in DNA-adduct levels was found in lung. The stimulation of DNA-adduct formation correlated with expression of CYP1A1/2 induced by the intra-tracheal instillation of 3-NBA. The results demonstrate that 3-NBA induces NQO1 and CYP1A1/2 in livers, lungs and kidneys of rats after intra-tracheal instillation, thereby enhancing its own genotoxic and carcinogenic potential.
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Affiliation(s)
- Jana Mizerovská
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, Czech Republic
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25
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Stiborová M, Martínek V, Svobodová M, Sístková J, Dvorák Z, Ulrichová J, Simánek V, Frei E, Schmeiser HH, Phillips DH, Arlt VM. Mechanisms of the different DNA adduct forming potentials of the urban air pollutants 2-nitrobenzanthrone and carcinogenic 3-nitrobenzanthrone. Chem Res Toxicol 2010; 23:1192-201. [PMID: 20545351 DOI: 10.1021/tx100052d] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
2-Nitrobenzanthrone (2-NBA) has recently been detected in ambient air particulate matter. Its isomer 3-nitrobenzanthrone (3-NBA) is a potent mutagen and suspected human carcinogen identified in diesel exhaust. We compared the efficiencies of human enzymatic systems [hepatic microsomes and cytosols, NAD(P)H:quinone oxidoreductase 1 (NQO1), xanthine oxidase, NADPH:cytochrome P450 reductase, N,O-acetyltransferases, and sulfotransferases] and human primary hepatocytes to activate 2-NBA and its isomer 3-NBA to species forming DNA adducts. In contrast to 3-NBA, 2-NBA was not metabolized at detectable levels by the tested human enzymatic systems and enzymes expressed in human hepatocytes, and no DNA adducts detectable by (32)P-postlabeling were generated by 2-NBA. Even NQO1, the most efficient human enzyme to bioactive 3-NBA, did not activate 2-NBA. Molecular docking of 2-NBA and 3-NBA to the active site of NQO1 showed similar binding affinities; however, the binding orientation of 2-NBA does not favor the reduction of the nitro group. This was in line with the inhibition of 3-NBA-DNA adduct formation by 2-NBA, indicating that 2-NBA can compete with 3-NBA for binding to NQO1, thereby decreasing the metabolic activation of 3-NBA. In addition, the predicted equilibrium conditions favor a 3 orders of magnitude higher dissociation of N-OH-3-ABA in comparison to N-OH-2-ABA. These findings explain the very different genotoxicity, mutagenicity, and DNA adduct forming potential of the two compounds. Collectively, our results suggest that 2-NBA possesses a relatively lower risk to humans than 3-NBA.
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Affiliation(s)
- Marie Stiborová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, Prague 2, Czech Republic.
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Martin FL, Patel II, Sozeri O, Singh PB, Ragavan N, Nicholson CM, Frei E, Meinl W, Glatt H, Phillips DH, Arlt VM. Constitutive expression of bioactivating enzymes in normal human prostate suggests a capability to activate pro-carcinogens to DNA-damaging metabolites. Prostate 2010; 70:1586-99. [PMID: 20687231 DOI: 10.1002/pros.21194] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND The constitutive bioactivating capacity of human prostate may play a role in determining risk of adenocarcinoma developing in this tissue. Expression of candidate enzymes that convert exogenous and/or endogenous agents into reactive DNA-damaging species would suggest the potential to generate initiating events in prostate cancer (CaP). METHODS Normal prostate tissues from UK-resident Caucasians (n = 10) were collected following either radical retropubic prostatectomy (RRP) or cystaprostatectomy (CyP). An analysis of gene and protein expression of candidate metabolizing enzymes, including cytochrome P450 (CYP)1A1, CYP1A2, CYP1B1, N-acetyltransferase 1 (NAT1), sulfotransferase (SULT)1A1, SULT1A3, NAD(P)H:quinone oxidoreductase (NQO1), prostaglandin H synthase 1 (cyclooxygenase 1; COX1), and CYP oxidoreductase (POR) was carried out. Quantitative real-time reverse transcriptase polymerase chain reaction, Western blot, and immunohistochemical analysis were conducted. RESULTS Except for CYP1A1 and CYP1A2, the metabolizing enzymes examined appeared to be expressed with minimal inter-individual variation (in general, approximately two- to fivefold) in the expression levels. Enzymes such as CYP1B1 and NQO1 that are capable of bioactivating pro-carcinogens to reactive metabolites were readily identifiable in human prostate. Immunohistochemical analysis showed that although some expression is located in the stroma, the majority is localized to epithelial cells lining the glandular elements of the tissue; these are the cells from which CaP might arise. CONCLUSION Constitutive expression of bioactivating enzymes confers the potential to convert a range of exogenous and/or endogenous agents to reactive species capable of inducing DNA damaging events. These findings suggest an organ capability for pro-carcinogen activation that could play an important role in the etiology of human CaP.
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Affiliation(s)
- Francis L Martin
- Centre for Biophotonics, Lancaster Environment Centre, Lancaster University, Lancaster, UK.
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Kucab JE, Phillips DH, Arlt VM. Linking environmental carcinogen exposure to TP53 mutations in human tumours using the human TP53 knock-in (Hupki) mouse model. FEBS J 2010. [DOI: 10.1111/j.1742-4658.2010.07676.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Landvik NE, Arlt VM, Nagy E, Solhaug A, Tekpli X, Schmeiser HH, Refsnes M, Phillips DH, Lagadic-Gossmann D, Holme JA. 3-Nitrobenzanthrone and 3-aminobenzanthrone induce DNA damage and cell signalling in Hepa1c1c7 cells. Mutat Res 2009; 684:11-23. [PMID: 19941874 DOI: 10.1016/j.mrfmmm.2009.11.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Revised: 11/03/2009] [Accepted: 11/18/2009] [Indexed: 01/27/2023]
Abstract
3-Nitrobenzanthrone (3-NBA) is a mutagenic and carcinogenic environmental pollutant found in diesel exhaust and urban air pollution. In the present work we have characterised the effects of 3-NBA and its metabolite 3-aminobenzanthrone (3-ABA) on cell death and cytokine release in mouse hepatoma Hepa1c1c7 cells. These effects were related to induced DNA damage and changes in cell signalling pathways. 3-NBA resulted in cell death and caused most DNA damage as judged by the amount of DNA adducts ((32)P-postlabelling assay), single strand (ss)DNA breaks and oxidative DNA lesions (comet assay) detected. An increased phosphorylation of H2AX, chk1, chk2 and partly ATM was observed using flow cytometry and/or Western blotting. Both compounds increased phosphorylation of p53 and MAPKs (ERK, p38 and JNK). However, only 3-NBA caused an accumulation of p53 in the nucleus and a translocation of Bax to the mitochondria. The p53 inhibitor pifithrin-alpha inhibited 3-NBA-induced apoptosis, indicating that cell death was a result of the triggering of DNA signalling pathways. The highest phosphorylation of Akt and degradation of IkappaB-alpha (suggesting activation of NF-kappaB) were also seen after treatment with 3-NBA. In contrast 3-ABA increased IL-6 release, but caused little or no toxicity. Cytokine release was inhibited by PD98059 and curcumin, suggesting that ERK and NF-kappaB play a role in this process. In conclusion, 3-NBA seems to have a higher potency to induce DNA damage compatible with its cytotoxic effects, while 3-ABA seems to have a greater effect on the immune system.
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Affiliation(s)
- N E Landvik
- Division of Environmental Medicine, Norwegian Institute of Public Health, P.O. Box 404 Torshov N-4303 Oslo, Norway
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Schmeiser HH, Fürstenberger G, Takamura-Enya T, Phillips DH, Arlt VM. The genotoxic air pollutant 3-nitrobenzanthrone and its reactive metabolite N-hydroxy-3-aminobenzanthrone lack initiating and complete carcinogenic activity in NMRI mouse skin. Cancer Lett 2009; 284:21-9. [PMID: 19442433 DOI: 10.1016/j.canlet.2009.04.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Revised: 03/30/2009] [Accepted: 04/01/2009] [Indexed: 11/28/2022]
Abstract
3-Nitrobenzanthrone (3-NBA), a genotoxic mutagen found in diesel exhaust and ambient air pollution and its active metabolite N-hydroxy-3-aminobenzanthrone (N-OH-3-ABA) were tested for initiating and complete carcinogenic activity in the NMRI mouse skin carcinogenesis model. Both compounds were found to be inactive as either tumour initiators or complete carcinogens in mouse skin over a dose range of 25-400nmol. Topical application of 3-NBA and N-OH-3-ABA produced DNA adduct patterns in epidermis, detected by (32)P-postlabelling, similar to those found previously in other organs of rats and mice. 24h after a single treatment of 100nmol DNA adduct levels produced by 3-NBA (18+/-4 adducts/10(8) nucleotides) were 6 times lower than those by 7,12-dimethylbenz[a]anthracene (DMBA; 114+/-37 adducts/10(8) nucleotides). In contrast, identical treatment with N-OH-3-ABA resulted in adduct levels in the same range as with DMBA (136+/-25 adducts/10(8) nucleotides), indicating that initial DNA adduct levels do not parallel tumour initiating activity. When compounds were tested for tumour initiating activity by a single treatment followed by twice-weekly applications of TPA, DNA adducts formed by DMBA, but not by 3-NBA or N-OH-3-ABA, were still detectable 40weeks after treatment. When tested for activity as complete carcinogens by twice-weekly topical application, 3-NBA and N-OH-3-ABA produced identical DNA adduct profiles in mouse skin, with adducts still detectable after 40weeks. Only 3-NBA produced detectable adducts in other organs.
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Affiliation(s)
- Heinz H Schmeiser
- Research Group Genetic Alterations in Carcinogenesis, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
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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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The mechanism of cytotoxicity and DNA adduct formation by the anticancer drug ellipticine in human neuroblastoma cells. Biochem Pharmacol 2009; 77:1466-79. [PMID: 19426684 DOI: 10.1016/j.bcp.2009.01.021] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 01/26/2009] [Accepted: 01/26/2009] [Indexed: 11/20/2022]
Abstract
Ellipticine is an antineoplastic agent, whose mode of action is based mainly on DNA intercalation, inhibition of topoisomerase II and formation of covalent DNA adducts mediated by cytochromes P450 and peroxidases. Here, the molecular mechanism of DNA-mediated ellipticine action in human neuroblastoma IMR-32, UKF-NB-3 and UKF-NB-4 cancer cell lines was investigated. Treatment of neuroblastoma cells with ellipticine resulted in apoptosis induction, which was verified by the appearance of DNA fragmentation, and in inhibition of cell growth. These effects were associated with formation of two covalent ellipticine-derived DNA adducts, identical to those formed by the cytochrome P450- and peroxidase-mediated ellipticine metabolites, 13-hydroxy- and 12-hydroxyellipticine. The expression of these enzymes at mRNA and protein levels and their ability to generate ellipticine-DNA adducts in neuroblastoma cells were proven, using the real-time polymerase chain reaction, Western blotting analyses and by analyzing ellipticine-DNA adducts in incubations of this drug with neuroblastoma S9 fractions, enzyme cofactors and DNA. The levels of DNA adducts correlated with toxicity of ellipticine to IMR-32 and UKF-NB-4 cells, but not with that to UKF-NB-3 cells. In addition, hypoxic cell culture conditions resulted in a decrease in ellipticine toxicity to IMR-32 and UKF-NB-4 cells and this correlated with lower levels of DNA adducts. Both these cell lines accumulated in S phase, suggesting that ellipticine-DNA adducts interfere with DNA replication. The results demonstrate that among the multiple modes of ellipticine antitumor action, formation of covalent DNA adducts by ellipticine is the predominant mechanism of cytotoxicity to IMR-32 and UKF-NB-4 neuroblastoma cells.
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Johansson T, Jurva U, Grönberg G, Weidolf L, Masimirembwa C. Novel Metabolites of Amodiaquine Formed by CYP1A1 and CYP1B1: Structure Elucidation Using Electrochemistry, Mass Spectrometry, and NMR. Drug Metab Dispos 2008; 37:571-9. [DOI: 10.1124/dmd.108.025171] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Reynisson J, Stiborová M, Martínek V, Gamboa da Costa G, Phillips DH, Arlt VM. Mutagenic potential of nitrenium ions of nitrobenzanthrones: correlation between theory and experiment. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2008; 49:659-67. [PMID: 18618595 DOI: 10.1002/em.20411] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The mutagenic activity of nine substituted nitrobenzanthrone (NBA) derivatives was recently established in the Ames assay and ranged from near inactivity to extremely high mutagenic activity (Takamura-Enya et al. 2006: Mutagenesis 21:399-404). Using thermochemical and molecular modeling techniques, the activation pathway of these NBA derivatives, namely 1-nitro-, 2-nitro-, 3-nitro-, 9-nitro-, 11-nitro-, 1,9-dinitro-, 3,9-dinitro-, 3,11-dinitro-, and 3,9,11-trinitrobenzanthrone, and the formation of the corresponding aryl-nitrenium ions, were investigated using density functional theory calculations. The calculated properties of the NBA derivatives were systematically compared with their bacterial mutagenic potency. Accommodation of the ligand substrates into the binding pocket of the bacterial nitroreductases was not sterically inhibited for the NBAs. Moreover, electron affinities, water elimination energies, esterification, and solvolysis energies did not reveal any possible links with the observed mutagenic potency of the NBAs. However, a strong negative linear correlation was found when the relative energies of the nitrenium ions of the mono and disubstituted NBAs were plotted against the logarithm of the mutagenic potency of the NBAs found in the different Salmonella typhimurium strains. Therefore, our data clearly indicate that the stability of the nitrenium ions is one critical determinant of the mutagenic potency of NBAs in Salmonella tester strains.
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Affiliation(s)
- Jóhannes Reynisson
- School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom.
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Arlt VM, Gingerich J, Schmeiser HH, Phillips DH, Douglas GR, White PA. Genotoxicity of 3-nitrobenzanthrone and 3-aminobenzanthrone in MutaMouse and lung epithelial cells derived from MutaMouse. Mutagenesis 2008; 23:483-90. [PMID: 18635558 DOI: 10.1093/mutage/gen037] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
FE1 lung epithelial cells derived from MutaMouse are a new model system to provide in vitro mutagenicity data with the potential to predict the outcome of an in vivo MutaMouse test. 3-Nitrobenzanthrone (3-NBA) is a potent mutagen and suspected human carcinogen identified in diesel exhaust and urban air pollution. We investigated the mutagenicity and DNA binding of 3-NBA and its main metabolite 3-aminobenzanthrone (3-ABA) in vitro and in vivo in the MutaMouse assay. Mice were treated with 3-NBA or 3-ABA (0, 2 or 5 mg/kg body weight/day) by gavage for 28 days and 28 days later lacZ mutant frequency (MF) was determined in liver, lung and bone marrow. For both compounds, dose-related increases in MF were seen in liver and bone marrow, but not in lung; mutagenic activity was approximately 2-fold lower for 3-ABA than for 3-NBA. With 3-NBA, highest DNA adduct levels (measured by (32)P-post-labelling) were found in liver (approximately 230 adducts per 10(8) nucleotides) with levels 20- to 40-fold lower in bone marrow and lung. With 3-ABA, DNA adduct levels were again highest in the liver, but approximately 4-fold lower than for 3-NBA. FE1 cells were exposed to up to 10 microg/ml 3-NBA or 3-ABA for 6 h with or without exogenous activation (S9) and harvested after 3 days. For 3-NBA, there was a dose-related increase in MF both with and without S9 mix, which was >10 times higher than observed in vivo. At the highest concentration of 3-ABA (10 microg/ml), we found only around a 2-fold increase in MF relative to controls. DNA adduct formation in FE1 cells was dose-dependent for both compounds, but 10- to 20-fold higher for 3-NBA compared to 3-ABA. Collectively, our data indicate that MutaMouse FE1 cells are well suited for cost-effective testing of suspected mutagens with different metabolic activation pathways as a guide for subsequent in vivo MutaMouse testing.
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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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Stiborová M, Dračínská H, Mizerovská J, Frei E, Schmeiser HH, Hudeček J, Hodek P, Phillips DH, Arlt VM. The environmental pollutant and carcinogen 3-nitrobenzanthrone induces cytochrome P450 1A1 and NAD(P)H:quinone oxidoreductase in rat lung and kidney, thereby enhancing its own genotoxicity. Toxicology 2008; 247:11-22. [DOI: 10.1016/j.tox.2008.01.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Revised: 01/23/2008] [Accepted: 01/25/2008] [Indexed: 10/22/2022]
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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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Mutagenicity and DNA adduct formation of PAH, nitro-PAH, and oxy-PAH fractions of atmospheric particulate matter from São Paulo, Brazil. Mutat Res 2008; 652:72-80. [PMID: 18294902 DOI: 10.1016/j.mrgentox.2007.12.007] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2007] [Revised: 12/14/2007] [Accepted: 12/21/2007] [Indexed: 10/22/2022]
Abstract
Urban particulate matter (UPM) contributes to lung cancer incidence. Here, we have studied the mutagenic activity and DNA adduct-forming ability of fractionated UPM extractable organic matter (EOM). UPM was collected with a high-volume sampler in June 2004 at two sites, one at street level adjacent to a roadway and the other inside a park within the urban area of the city of São Paulo, Brazil. UPM was extracted using dichloromethane, and the resulting EOM was separated by HPLC to obtain PAH, nitro-PAH, and oxy-PAH fractions which were tested for mutagenicity with the Salmonella strains TA98 and YG1041 with and without S9 metabolic activation. The PAH fraction from both sites showed negligible mutagenic activity in both strains. The highest mutagenic activity was found for the nitro-PAH fraction using YG1041 without metabolic activation; however, results were comparable for both sites. The nitro-PAH and oxy-PAH fractions were incubated with calf thymus DNA under reductive conditions appropriate for the activation of nitro aromatic compounds, then DNA adduct patterns and levels were determined with thin-layer chromatography (TLC) 32P-postlabeling method using two enrichment procedures-nuclease P1 digestion and butanol extraction. Reductively activated fractions from both sites produced diagonal radioactive zones (DRZ) of putative aromatic DNA adducts on thin layer plates with both enrichment procedures. No such DRZ were observed in control experiments using fractions from unexposed filters or from incubations without activating system. Total adduct levels produced by the nitro-PAH fractions were similar for both sites ranging from 30 to 45 adducts per 10(8) normal nucleotides. In contrast, the DNA binding of reductively activated oxy-PAH fractions was three times higher and the adduct pattern consisted of multiple discrete spots along the diagonal line on the thin layer plates. However, DNA adduct levels were not significantly different between the sampling sites. Both samples presented the same levels of mutagenic activity. The response in the Salmonella assay was typical of nitroaromatics. Although, more mutagenic activity was related to the nitro-PAH fraction in the Salmonella assay, the oxy-PAH fractions showed the highest DNA adduct levels. More studies are needed to elucidate the nature of the genotoxicants occurring in São Paulo atmospheric samples.
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Takamura-Enya T, Kawanishi M, Yagi T, Hisamatsu Y. Structural identification of DNA adducts derived from 3-nitrobenzanthrone, a potent carcinogen present in the atmosphere. Chem Asian J 2007; 2:1174-85. [PMID: 17712830 DOI: 10.1002/asia.200700061] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
3-Nitrobenzanthrone is a powerful bacterial mutagen and carcinogen to mammals. To obtain precise information on DNA-adduct formation by 3-nitrobenzanthrone, a number of DNA adducts, including N-(2'-deoxyguanosin-8-yl)-3-aminobenzanthrone (13 a), 2-(2'-deoxyguanosin-N2-yl)-3-aminobenzanthrone (14 a), N-(2'-deoxyadenosin-8-yl)-3-aminobenzanthrone (15 a), 2-(2'-deoxyadenosin-N6-yl)-3-aminobenzanthrone (16 a), and their N-acetylated counterparts 13 b, 14 b, 15 b, and 16 b were synthesized by palladium-catalyzed aryl amination of the corresponding nucleoside and bromobenzanthrone derivatives. Among these DNA adducts, DNA adducts 13 a, 13 b, 14 a, 14 b, and 16 a were identified in the reaction mixture of nucleosides (2'-deoxyguanosine, 2'-deoxyadenosine, or DNA) with N-acetoxy-3-aminobenzanthrone or N-acetyl-N-acetoxy-3-aminobenzanthrone, both of which are recognized as activated metabolites of 3-nitrobenzanthrone. The formation of these multiple DNA adducts may help explain the potent mutacarcinogenicity of 3-nitrobenzanthrone.
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Affiliation(s)
- Takeji Takamura-Enya
- Department of Applied Chemistry, Kanagawa Institute of Technology, 1030 Shimo-Ogino, Atsugi-shi 243-0292, Japan.
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Aimová D, Svobodová L, Kotrbová V, Mrázová B, Hodek P, Hudecek J, Václavíková R, Frei E, Stiborová M. The Anticancer Drug Ellipticine Is a Potent Inducer of Rat Cytochromes P450 1A1 and 1A2, Thereby Modulating Its Own Metabolism. Drug Metab Dispos 2007; 35:1926-34. [PMID: 17656468 DOI: 10.1124/dmd.107.016048] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ellipticine is an antineoplastic agent whose mode of action is based mainly on DNA intercalation, inhibition of topoisomerase II, and formation of covalent DNA adducts mediated by cytochromes P450 (P450s) and peroxidases. Here, this drug was found to induce CYP1A1 and/or 1A2 enzymes and their enzymatic activities in livers, lungs, and kidneys of rats treated (i.p.) with ellipticine. The induction is transient. In the absence of repeated administration of ellipticine, the levels and activities of the induced CYP1A decreased almost to the basal level 2 weeks after treatment. The ellipticine-mediated CYP1A induction increases the DNA adduct formation by the compound. When microsomal fractions from livers, kidneys, and lungs of rats treated with ellipticine were incubated with ellipticine, DNA adduct formation, measured by (32)P-postlabeling analysis, was up to 3.8-fold higher in incubations with microsomes from pretreated rats than with controls. The observed stimulation of DNA adduct formation by ellipticine was attributed to induction of CYP1A1 and/or 1A2-mediated increase in ellipticine oxidative activation to 13-hydroxy- and 12-hydroxyellipticine, the metabolites generating two major DNA adducts in human and rat livers. In addition to these metabolites, increased formation of the excretion products 9-hydroxy- and 7-hydroxyellipticine was also observed in microsomes of rats treated with ellipticine. Taken together, these results demonstrate for the first time that by inducing CYP1A1/2, ellipticine increases its own metabolism, leading both to an activation of this drug to reactive species-forming DNA adducts and to detoxication metabolites, thereby modulating to some extent its pharmacological and/or genotoxic potential.
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Affiliation(s)
- Dagmar Aimová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
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Matsumoto Y, Ide F, Kishi R, Akutagawa T, Sakai S, Nakamura M, Ishikawa T, Fujii-Kuriyama Y, Nakatsuru Y. Aryl hydrocarbon receptor plays a significant role in mediating airborne particulate-induced carcinogenesis in mice. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2007; 41:3775-80. [PMID: 17547212 DOI: 10.1021/es062793g] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Urban particulate air pollution is associated with an increased incidence of cancers, and especially lung cancer. Organic extracts of airborne particulate matter (APM) cause cancer in mice, and PAHs adsorbed to APM are associated with particle-induced carcinogenesis. PAHs are agonists for AhR and are predominantly responsible for lung cancer through induction of highly carcinogenic metabolites. PAH metabolization requires CYP1A1 induction through activation of AhR, and therefore we hypothesized that carcinogenesis due to PAHs in APM would be reduced in AhR-/- mice. To examine this hypothesis, we performed a long-term continuous-application study of carcinogenesis in AhR-/- mice using airborne particulate extract (APE) of APM collected in Sapporo. Tumor development (squamous cell carcinoma) occurred in 8 of 17 AhR+/+ mice (47%), but no tumors were found in AhR-/-mice, and CYP1A1 was induced in AhR+/+ mice but not in AhR-/- mice. These results demonstrate that AhR plays a significant role in APE-induced carcinogenesis in AhR+/+ mice and CYP1A1 activation of carcinogenic PAHs is also of importance. Therefore, measurement of CYP1A1 induction in vitro may be useful for assessment of APM-induced carcinogenesis in humans. We also show that PAH-like compounds are major contributors to AhR-mediated carcinogenesis, whereas TCDD and related compounds make a smaller contribution.
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Affiliation(s)
- Yutaka Matsumoto
- Department of Public Health, Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
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Hansen T, Seidel A, Borlak J. The environmental carcinogen 3-nitrobenzanthrone and its main metabolite 3-aminobenzanthrone enhance formation of reactive oxygen intermediates in human A549 lung epithelial cells. Toxicol Appl Pharmacol 2007; 221:222-34. [PMID: 17477947 DOI: 10.1016/j.taap.2007.03.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Revised: 03/02/2007] [Accepted: 03/07/2007] [Indexed: 01/18/2023]
Abstract
The environmental contaminant 3-nitrobenzanthrone (3-NBA) is highly mutagenic and a suspected human carcinogen. We aimed to evaluate whether 3-NBA is able to deregulate critical steps in cell cycle control and apoptosis in human lung epithelial A549 cells. Increased intracellular Ca(2+) and caspase activities were detected upon 3-NBA exposure. As shown by cell cycle analysis, an increased number of S-phase cells was observed after 24 h of treatment with 3-NBA. Furthermore, 3-NBA was shown to inhibit cell proliferation when added to subconfluent cell cultures. The main metabolite of 3-NBA, 3-ABA, induced statistically significant increases in tail moment as judged by alkaline comet assay. The potential of 3-NBA and 3-ABA to enhance the production of reactive oxygen species (ROS) was demonstrated by flow cytometry using 2',7'-dichlorofluorescein-diacetate (DCFH-DA). The enzyme inhibitors allopurinol, dicumarol, resveratrol and SKF525A were used to assess the impact of metabolic conversion on 3-NBA-mediated ROS production. Resveratrol decreased dichlorofluorescein (DCF) fluorescence by 50%, suggesting a role for CYP1A1 in 3-NBA-mediated ROS production. Mitochondrial ROS production was significantly attenuated (20% reduction) by addition of rotenone (complex I inhibition) and thenoyltrifluoroacetone (TTFA, complex II inhibition). Taken together, the results of the present study provide evidence for a genotoxic potential of 3-ABA in human epithelial lung cells. Moreover, both compounds lead to increased intracellular ROS and create an environment favorable to DNA damage and the promotion of cancer.
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Affiliation(s)
- Tanja Hansen
- Fraunhofer Institute of Toxicology and Experimental Medicine, Hannover, Germany.
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Stiborová M, Dračínská H, Aimová D, Hodek P, Hudeček J, Ryšlavá H, Schmeiser HH, Frei E. The Anticancer Drug Ellipticine is an Inducer of Rat NAD(P)H:Quinone Oxidoreductase. ACTA ACUST UNITED AC 2007. [DOI: 10.1135/cccc20071350] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The antineoplastic agent ellipticine was investigated for its ability to induce the biotransformation enzyme NAD(P)H:quinone oxidoreductase (DT-diaphorase, EC 1.6.99.2) in male Wistar rats. Using the real-time polymerase chain reaction, the levels of NAD(P)H:quinone oxidoreductase mRNA were determined in livers, kidneys and lungs of rats treated intraperitoneally with ellipticine (40 mg/kg body weight) and of control (untreated) rats. Cytosolic fractions were isolated from the same tissues of control and ellipticine-treated rats and tested for NAD(P)H:quinone oxidoreductase protein expression and its enzymatic activity. The results demonstrate that ellipticine is a potent inducer of NAD(P)H:quinone oxidoreductase in rat livers and kidneys, while no induction of this enzyme was detectable in rat lungs. The increase in levels of NAD(P)H:quinone oxidoreductase mRNA correlates with the increase in expression of its protein and enzymatic activity, measured with menadione and 3-nitrobenzanthrone as substrates. The results, the identification of the potential of ellipticine to induce NAD(P)H:quinone oxidoreductase, suggest that this drug is capable of modulating biological efficiencies of the toxicants and/or drugs that are reductively metabolized by this enzyme.
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