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Yamada T, Kawamura T, Tsujii S, Miura M, Ohata H, Katsutani N, Matsumoto M, Hirose A. Formation and evaluation of mechanism-based chemical categories for regulatory read-across assessment of repeated-dose toxicity: A case of hemolytic anemia. Regul Toxicol Pharmacol 2022; 136:105275. [DOI: 10.1016/j.yrtph.2022.105275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 09/20/2022] [Accepted: 10/07/2022] [Indexed: 11/05/2022]
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Abdel-Rahman MA, Shibl MF, El-Nahas AM, Abdel-Azeim S, El-demerdash SH, Al-Hashimi N. Mechanistic insights of the degradation of an O-anisidine carcinogenic pollutant initiated by OH radical attack: theoretical investigations. NEW J CHEM 2021. [DOI: 10.1039/d0nj06248k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
O-Anisidine (O-AND) is one of the amino organic compounds that harm human health, and is considered as a carcinogenic chemical.
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Affiliation(s)
| | - Mohamed F. Shibl
- Department of Chemistry and Earth Sciences
- College of Arts and Sciences
- Qatar University
- Doha
- Qatar
| | - Ahmed M. El-Nahas
- Chemistry Department
- Faculty of Science
- Menoufia University
- Shebin El-Kom 32512
- Egypt
| | - Safwat Abdel-Azeim
- Center for Integrative Petroleum Research (CIPR)
- College of Petroleum Engineering and Geosciences
- King Fahd University of Petroleum and Minerals (KFUPM)
- Dhahran 31261
- Saudi Arabia
| | | | - Nessreen Al-Hashimi
- Department of Chemistry and Earth Sciences
- College of Arts and Sciences
- Qatar University
- Doha
- Qatar
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Wewering F, Jouy F, Caliskan S, Kalkhof S, von Bergen M, Luch A, Zellmer S. Hepatic co-cultures in vitro reveal suitable to detect Nrf2-mediated oxidative stress responses on the bladder carcinogen o-anisidine. Toxicol In Vitro 2017; 40:153-160. [PMID: 28089782 DOI: 10.1016/j.tiv.2017.01.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 01/07/2017] [Accepted: 01/11/2017] [Indexed: 11/15/2022]
Abstract
The azo dye o-anisidine is known as an industrial and environmental pollutant. Metabolites of o-anisidine remain in the liver for >24h. However, the toxicological impact of o-anisidine on the liver and its individual cell types, e.g., hepatocytes and immune cells, is currently poorly understood. A novel co-culture system, composed of HepG2 or Huh-7 cells, and differentiated THP-1 cells was used to study the metabolic capacity towards o-anisidine, and compared to primary murine hepatocytes which express high enzyme activities. As model compounds the carcinogenic arylamine o-anisidine and its non-carcinogenic isomer, p-anisidine, as well as caffeine were used. Global proteome analysis revealed an activation of eIF2 and Nrf2-mediated oxidative stress response pathways only in co-cultures after treatment with o-anisidine. This was confirmed via detection of reactive oxygen species. In addition, the mitochondrial membrane potential decreased already after 3h treatment of cells, which correlated with a decrease of ATP levels (R2>0.92). In the supernatant of co-cultured, but not single-cultured HepG2 and Huh-7 cells, o-anisidine caused increases of damage-associated proteins, such as HMGB1 (high mobility group box-1) protein. In summary, only co-cultures of HepG2 and THP-1 cells predict o-anisidine induced stress responsive pathways, since the system has a higher sensitivity compared to single cultured cells.
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Affiliation(s)
- Franziska Wewering
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Strasse 8-10, 10589 Berlin, Germany.
| | - Florent Jouy
- Department of Molecular Systems Biology, UFZ, Helmholtz-Centre for Environmental Research, Permoserstrasse 15, 04318 Leipzig, Germany
| | - Sükran Caliskan
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Strasse 8-10, 10589 Berlin, Germany
| | - Stefan Kalkhof
- Department of Molecular Systems Biology, UFZ, Helmholtz-Centre for Environmental Research, Permoserstrasse 15, 04318 Leipzig, Germany; Department of Bioanalytics, University of Applied Sciences and Arts of Coburg, 96450 Coburg, Germany
| | - Martin von Bergen
- Department of Molecular Systems Biology, UFZ, Helmholtz-Centre for Environmental Research, Permoserstrasse 15, 04318 Leipzig, Germany; Department of Biochemistry, Faculty of Biosciences, Pharmacy and Psychology, University of Leipzig, Brüderstrasse 34, 04103 Leipzig, Germany; Department of Chemistry and Bioscience, Aalborg University, DK-9220 Aalborg, Denmark
| | - Andreas Luch
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Strasse 8-10, 10589 Berlin, Germany
| | - Sebastian Zellmer
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Strasse 8-10, 10589 Berlin, Germany
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Naiman K, Martínková M, Schmeiser HH, Frei E, Stiborová M. Human cytochrome-P450 enzymes metabolize N-(2-methoxyphenyl)hydroxylamine, a metabolite of the carcinogens o-anisidine and o-nitroanisole, thereby dictating its genotoxicity. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2011; 726:160-8. [DOI: 10.1016/j.mrgentox.2011.09.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Revised: 08/22/2011] [Accepted: 09/05/2011] [Indexed: 10/17/2022]
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Cytochrome P450-mediated metabolism of N-(2-methoxyphenyl)-hydroxylamine, a human metabolite of the environmental pollutants and carcinogens o-anisidine and o-nitroanisole. Interdiscip Toxicol 2011; 1:218-24. [PMID: 21218119 PMCID: PMC2994023 DOI: 10.2478/v10102-010-0045-8] [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: 11/28/2008] [Revised: 12/05/2008] [Accepted: 12/07/2008] [Indexed: 11/20/2022] Open
Abstract
N-(2-methoxyphenyl)hydroxylamine is a human metabolite of the industrial and environmental pollutants and bladder carcinogens 2-methoxyaniline (o-anisidine) and 2-methoxynitrobenzene (o-nitroanisole). Here, we investigated the ability of hepatic microsomes from rat and rabbit to metabolize this reactive compound. We found that N-(2-methoxyphenyl)hydroxylamine is metabolized by microsomes of both species mainly to o-aminophenol and a parent carcinogen, o-anisidine, whereas 2-methoxynitrosobenzene (o-nitrosoanisole) is formed as a minor metabolite. Another N-(2-methoxyphenyl)hydroxylamine metabolite, the exact structure of which has not been identified as yet, was generated by hepatic microsomes of rabbits, but its formation by those of rats was negligible. To evaluate the role of rat hepatic microsomal cytochromes P450 (CYP) in N-(2-methoxyphenyl)hydroxylamine metabolism, we investigated the modulation of its metabolism by specific inducers of these enzymes. The results of this study show that rat hepatic CYPs of a 1A subfamily and, to a lesser extent those of a 2B subfamily, catalyze N-(2-methoxyphenyl)hydroxylamine conversion to form both its reductive metabolite, o-anisidine, and o-aminophenol. CYP2E1 is the most efficient enzyme catalyzing conversion of N-(2-methoxyphenyl)hydroxylamine to o-aminophenol.
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Genotoxic mechanisms for the carcinogenicity of the environmental pollutants and carcinogens o-anisidine and 2-nitroanisole follow from adducts generated by their metabolite N-(2-methoxyphenyl)-hydroxylamine with deoxyguanosine in DNA. Interdiscip Toxicol 2011; 2:24-7. [PMID: 21217841 PMCID: PMC2984092 DOI: 10.2478/v10102-009-0004-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2009] [Revised: 03/25/2009] [Accepted: 04/01/2009] [Indexed: 11/21/2022] Open
Abstract
An aromatic amine, o-anisidine (2-methoxyaniline) and its oxidative counterpart, 2-nitroanisole (2-methoxynitrobenzene), are the industrial and environmental pollutants causing tumors of the urinary bladder in rats and mice. Both carcinogens are activated to the same proximate carcinogenic metabolite, N-(2-methoxyphenyl)hydroxylamine, which spontaneously decomposes to nitrenium and/or carbenium ions responsible for formation of deoxyguanosine adducts in DNA in vitro and in vivo. In other words, generation of N-(2-methoxyphenyl)hydroxylamine is responsible for the genotoxic mechanisms of the o-anisidine and 2-nitroanisole carcinogenicity. Analogous enzymes of human and rat livers are capable of activating these carcinogens. Namely, human and rat cytochorme P4502E1 is the major enzyme oxidizing o-anisidine to N-(2-methoxyphenyl)hydroxylamine, while xanthine oxidase of both species reduces 2-nitroanisole to this metabolite. Likewise, O-demethylation of 2-nitroanisole, which is the detoxication pathway of its metabolism, is also catalyzed by the same human and rat enzyme, cytochorme P450 2E1. The results demonstrate that the rat is a suitable animal model mimicking the fate of both carcinogens in humans and suggest that both compounds are potential carcinogens also for humans.
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Naiman K, Hodek P, Liberda J, Schmeiser HH, Frei E, Stiborová M. Rat liver microsomal metabolism of o-aminophenol and N-(2-methoxyphenyl)hydroxylamine, two metabolites of the environmental pollutant and carcinogen o-anisidine in humans. ACTA ACUST UNITED AC 2010. [DOI: 10.1135/cccc2010077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
o-Aminophenol and N-(2-methoxyphenyl)hydroxylamine are human metabolites of the industrial and environmental pollutant and bladder carcinogen 2-methoxyaniline (o-anisidine). The latter one is also a human metabolite of another pollutant and bladder carcinogen, 2-methoxynitrobenzene (o-nitroanisole). Here, we investigated the ability of rat hepatic micro- somes to metabolize these metabolites. N-(2-methoxyphenyl)hydroxylamine is metabolized by rat hepatic microsomes to o-aminophenol and predominantly o-anisidine, the parent carcinogen from which N-(2-methoxyphenyl)hydroxylamine is formed. In addition, two N-(2-methoxyphenyl)hydroxylamine metabolites, whose exact structures have not been identified as yet, were generated. On the contrary, no metabolites were found to be formed from o-aminophenol by rat hepatic microsomes. Whereas N-(2-methoxyphenyl)hydroxylamine is responsible for formation of three deoxyguanosine adducts in DNA, o-aminophenol seems to be a detoxication metabolite of N-(2-methoxyphenyl)hydroxylamine and/or a parental carcinogen, o-anisidine; no o-aminophenol-derived DNA adducts were found after its reaction with microsomal cytochromes P450 and peroxidases.
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Naiman K, Dracínská H, Martínková M, Sulc M, Dracínský M, Kejíková L, Hodek P, Hudecek J, Liberda J, Schmeiser HH, Frei E, Stiborová M. Redox cycling in the metabolism of the environmental pollutant and suspected human carcinogen o-anisidine by rat and rabbit hepatic microsomes. Chem Res Toxicol 2008; 21:1610-21. [PMID: 18624415 DOI: 10.1021/tx8001127] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We investigated the ability of hepatic microsomes from rat and rabbit to metabolize 2-methoxyaniline (o-anisidine), an industrial and environmental pollutant and a bladder carcinogen for rodents. Using HPLC combined with electrospray tandem mass spectrometry, we determined that o-anisidine is oxidized by microsomes of both species to N-(2-methoxyphenyl)hydroxylamine, o-aminophenol, and one additional metabolite, the exact structure of which has not been identified as yet. N-(2-Methoxyphenyl)hydroxylamine is either further oxidized to 2-methoxynitrosobenzene (o-nitrosoanisole) or reduced to parental o-anisidine, which can be oxidized again to produce o-aminophenol. To define the role of microsomal cytochromes P450 (P450) in o-anisidine metabolism, we investigated the modulation of this metabolism by specific inducers and selective inhibitors of these enzymes. The results of the studies suggest that o-anisidine is a promiscuous substrate of P450s of rat and rabbit liver; because P450s of 1A, 2B, 2E, and 3A subfamilies metabolize o-anisidine in hepatic microsomes of both studied species. Using purified enzymes of rat and rabbit (P450s 1A1, 1A2, 2B2, 2B4, 2E1, 2C3, 3A1, and 3A6), reconstituted with NADPH:P450 reductase, the ability of P450s 1A1, 1A2, 2B2, 2B4, 2E1, and 3A6 to metabolize o-anisidine was confirmed. In the reconstituted P450 system, rabbit P450 2E1 was the most efficient enzyme metabolizing o-anisidine. The data demonstrate the participation of different rat and rabbit P450s in o-anisidine metabolism and indicate that both experimental animal species might serve as suitable models to mimic the fate of o-anisidine in human.
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Affiliation(s)
- Karel Naiman
- Department of Biochemistry, Faculty of Science, Charles University, AlbertoV 2030, 128 40 Prague 2, Czech Republic
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