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Luo W, Hu K, Chen Y, Wang L, Liu Y. Specific human CYP enzymes-dependent mutagenicity of tris(2-butoxyethyl) phosphate (an organophosphorus flame retardant) in human and hamster cell lines. Chem Biol Interact 2024; 397:111088. [PMID: 38823534 DOI: 10.1016/j.cbi.2024.111088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 05/07/2024] [Accepted: 05/29/2024] [Indexed: 06/03/2024]
Abstract
Tris(2-butoxyethyl) phosphate (TBOEP) is an organophosphorus flame retardant ubiquitously present in the environment and even the human body. TBOEP is toxic in multiple tissues, which forms dealkylated and hydroxylated metabolites under incubation with human hepatic microsomes; however, the impact of TBOEP metabolism on its toxicity, particularly mutagenicity (typically requiring metabolic activation), is left unidentified. In this study, the mutagenicity of TBOEP in human hepatoma cell lines (HepG2 and C3A) and the role of specific CYPs were studied. Through molecular docking, TBOEP bound to human CYP1A1, 1B1, 2B6 and 3A4 with energies and conformations favorable for catalyzing reactions, while the conformations of its binding with human CYP1A2 and 2E1 appeared unfavorable. In C3A cells (endogenous CYPs being substantial), TBOEP exposing for 72 h (2-cell cycle) at low micromolar levels induced micronucleus, which was abolished by 1-aminobenzotriazole (inhibitor of CYPs); in HepG2 cells (CYPs being insufficient) TBOEP did not induce micronucleus, whose effect was however potentiated by pretreating the cells with PCB126 (CYP1A1 inducer) or rifampicin (CYP3A4 inducer). TBOEP induced micronucleus in Chinese hamster V79-derived cell lines genetically engineered for stably expressing human CYP1A1 and 3A4, but not in cells expressing the other CYPs. In C3A cells, TBOEP selectively induced centromere protein B-free micronucleus (visualized by immunofluorescence) and PIG-A gene mutations, and elevated γ-H2AX rather than p-H3 (by Western blot) which indicated specific double-strand DNA breaks. Therefore, this study suggests that TBOEP may induce DNA/chromosome breaks and gene mutations in human cells, which requires metabolic activation by CYPs, primarily CYP1A1 and 3A4.
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Affiliation(s)
- Wenwen Luo
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China
| | - Keqi Hu
- Department of Science and Education, Guangdong Second Provincial General Hospital, 466 Xingang Middle Road, Guangzhou, 510317, China
| | - Yijing Chen
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China
| | - Lin Wang
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China
| | - Yungang Liu
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China.
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Chen Y, Yang Z, Zhou Z, Liu EJ, Luo W, He Z, Han W, Liu Y. Metabolism-dependent mutagenicity of two structurally similar tobacco-specific nitrosamines (N-nitrosonornicotine and N-nitrosoanabasine) in human cells, partially different CYPs being activating enzymes. Toxicology 2024; 504:153774. [PMID: 38490321 DOI: 10.1016/j.tox.2024.153774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 03/09/2024] [Accepted: 03/11/2024] [Indexed: 03/17/2024]
Abstract
N-nitrosonornicotine (NNN) and N-nitrosoanabasine (NAB) are both tobacco-specific nitrosamines bearing two heterocyclic amino groups, NAB bearing an extra -CH2- group (conferring a hexa- rather than penta-membered cycle) but with significantly decreased carcinogenicity. However, their activating enzymes and related mutagenicity remain unclear. In this study, the chemical-CYP interaction was analyzed by molecular docking, thus the binding energies and conformations of NNN for human CYP2A6, 2A13, 2B6, 2E1 and 3A4 appeared appropriate as a substrate, so did NAB for human CYP1B1, 2A6, 2A13 and 2E1. The micronucleus test in human hepatoma (HepG2) cells with each compound (62.5-1000 μM) exposing for 48 h (two-cell cycle) was negative, however, pretreatment with bisphenol AF (0.1-100 nM, CYPs inducer) and ethanol (0.2% v:v, CYP2E1 inducer) potentiated micronucleus formation by both compounds, while CITCO (1 μM, CYP2B6 inducer) selectively potentiated that by NNN. In C3A cells (endogenous CYPs enhanced over HepG2) both compounds induced micronucleus, which was abolished by 1-aminobenzotriazole (60 μM, CYPs inhibitor) while unaffected by 8-methoxypsoralen (1 μM, CYP2A inhibitor). Consistently, NNN and NAB induced micronucleus in V79-derived recombinant cell lines expressing human CYP2B6/2E1 and CYP1B1/2E1, respectively, while negative in those expressing other CYPs. By immunofluorescent assay both compounds selectively induced centromere-free micronucleus in C3A cells. In PIG-A assays in HepG2 cells NNN and NAB were weakly positive and simply negative, respectively; however, in C3A cells both compounds significantly induced gene mutations, NNN being slight more potent. Conclusively, both NNN and NAB are mutagenic and clastogenic, depending on metabolic activation by partially different CYP enzymes.
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Affiliation(s)
- Yijing Chen
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou 510515, China
| | - Zongying Yang
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou 510515, China; School of Clinical Technology, Sichuan Vocational College of Health and Rehabilitation, 3 Deming Road, Zigong, Sichuan Province 643000, China
| | - Zhao Zhou
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou 510515, China
| | - Ellery J Liu
- International High School Section, Guangzhou Experimental Foreign Language School, 599 Guanghuayi Road, Guangzhou 510440, China
| | - Wenwen Luo
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou 510515, China
| | - Zhini He
- Research Center of Food Safety and Health, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou 510515, China
| | - Weili Han
- Department of inspection and quarantine, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou 510515, China
| | - Yungang Liu
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou 510515, China.
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Miao YS, Wang JY, Zhuang RR, Huo XK, Yi ZC, Sun XN, Yu ZL, Tian XG, Ning J, Feng L, Ma XC, Lv X. A high-affinity fluorescent probe for human uridine-disphosphate glucuronosyltransferase 1A9 function monitoring under environmental pollutant exposure. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133439. [PMID: 38218035 DOI: 10.1016/j.jhazmat.2024.133439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 12/30/2023] [Accepted: 01/02/2024] [Indexed: 01/15/2024]
Abstract
Uridine-disphosphate glucuronosyltransferase 1A9 (UGT1A9), an important detoxification and inactivation enzyme for toxicants, regulates the exposure level of environmental pollutants in the human body and induces various toxicological consequences. However, an effective tool for high-throughput monitoring of UGT1A9 function under exposure to environmental pollutants is still lacking. In this study, 1,3-dichloro-7-hydroxy-9,9-dimethylacridin-2(9H)-one (DDAO) was found to exhibit excellent specificity and high affinity towards human UGT1A9. Remarkable changes in absorption and fluorescence signals after reacting with UGT1A9 were observed, due to the intramolecular charge transfer (ICT) mechanism. Importantly, DDAO was successfully applied to monitor the biological functions of UGT1A9 in response to environmental pollutant exposure not only in microsome samples, but also in living cells by using a high-throughput screening method. Meanwhile, the identified pollutants that disturb UGT1A9 functions were found to significantly influence the exposure level and retention time of bisphenol S/bisphenol A in living cells. Furthermore, the molecular mechanism underlying the inhibition of UGT1A9 by these pollutant-derived disruptors was elucidated by molecular docking and molecular dynamics simulations. Collectively, a fluorescent probe to characterize the responses of UGT1A9 towards environmental pollutants was developed, which was beneficial for elucidating the health hazards of environmental pollutants from a new perspective.
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Affiliation(s)
- Yi-Sheng Miao
- Second Affiliated Hospital, Dalian Medical University, Dalian 116023, China; College of Integrative Medicine, Dalian Medical University, Dalian 116044, China
| | - Jia-Yue Wang
- Second Affiliated Hospital, Dalian Medical University, Dalian 116023, China; College of Integrative Medicine, Dalian Medical University, Dalian 116044, China
| | - Rui-Rui Zhuang
- College of Integrative Medicine, Dalian Medical University, Dalian 116044, China
| | - Xiao-Kui Huo
- Second Affiliated Hospital, Dalian Medical University, Dalian 116023, China
| | - Zi-Chang Yi
- College of Integrative Medicine, Dalian Medical University, Dalian 116044, China
| | - Xiao-Nan Sun
- College of Integrative Medicine, Dalian Medical University, Dalian 116044, China; School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007, China
| | - Zhen-Long Yu
- College of Integrative Medicine, Dalian Medical University, Dalian 116044, China
| | - Xiang-Ge Tian
- Second Affiliated Hospital, Dalian Medical University, Dalian 116023, China
| | - Jing Ning
- College of Integrative Medicine, Dalian Medical University, Dalian 116044, China
| | - Lei Feng
- Second Affiliated Hospital, Dalian Medical University, Dalian 116023, China; Chengdu University of Traditional Chinese Medicine, Chengdu 611137 China.
| | - Xiao-Chi Ma
- Second Affiliated Hospital, Dalian Medical University, Dalian 116023, China; Heilongjiang University of Chinese Medicine, Harbin 150040, China.
| | - Xia Lv
- Second Affiliated Hospital, Dalian Medical University, Dalian 116023, China; College of Integrative Medicine, Dalian Medical University, Dalian 116044, China.
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Kovačič A, Modic M, Hojnik N, Štampar M, Gulin MR, Nannou C, Koronaiou LA, Heath D, Walsh JL, Žegura B, Lambropoulou D, Cvelbar U, Heath E. Degradation and toxicity of bisphenol A and S during cold atmospheric pressure plasma treatment. JOURNAL OF HAZARDOUS MATERIALS 2023; 454:131478. [PMID: 37116332 DOI: 10.1016/j.jhazmat.2023.131478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 04/06/2023] [Accepted: 04/22/2023] [Indexed: 05/19/2023]
Abstract
Bisphenols are widely recognised as toxic compounds that potentially threaten the environment and public health. Here we report the use of cold atmospheric pressure plasma (CAP) to remove bisphenol A (BPA) and bisphenol S (BPS) from aqueous systems. Additionally, methanol was added as a radical scavenger to simulate environmental conditions. After 480 s of plasma treatment, 15-25 % of BPA remained, compared to > 80 % of BPS, with BPA being removed faster (-kt = 3.4 ms-1, half-life = 210 s) than BPS (-kt = 0.15 ms-1, half-life 4700 s). The characterisation of plasma species showed that adding a radical scavenger affects the formation of reactive oxygen and nitrogen species, resulting in a lower amount of ˙OH, H2O2, and NO2- but a similar amount of NO3-. In addition, a non-target approach enabled the elucidation of 11 BPA and five BPS transformation products. From this data, transformation pathways were proposed for both compounds, indicating nitrification with further cleavage, demethylation, and carboxylation, and the coupling of smaller bisphenol intermediates. The toxicological characterisation of the in vitro HepG2 cell model has shown that the mixture of transformation products formed during CAP is less toxic than BPA and BPS, indicating that CAP is effective in safely degrading bisphenols.
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Affiliation(s)
- Ana Kovačič
- Department of Environmental Sciences O2, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Jamova 39, 1000 Ljubljana, Slovenia
| | - Martina Modic
- Jožef Stefan International Postgraduate School, Jamova 39, 1000 Ljubljana, Slovenia; Laboratory for Gaseous Electronics F6, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | - Nataša Hojnik
- Jožef Stefan International Postgraduate School, Jamova 39, 1000 Ljubljana, Slovenia; Laboratory for Gaseous Electronics F6, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | - Martina Štampar
- National Institute of Biology, Department of Genetic Toxicology and Cancer Biology, 1000 Ljubljana, Slovenia
| | - Martin Rafael Gulin
- Department of Environmental Sciences O2, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | - Christina Nannou
- Department of Chemistry, International Hellenic University, GR 65404 Kavala, Greece
| | - Lelouda-Athanasia Koronaiou
- Laboratory of Environmental Pollution Control, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece; Center for Interdisciplinary Research and Innovation (CIRI-AUTh), Thessaloniki GR-57001, Greece
| | - David Heath
- Department of Environmental Sciences O2, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | - James L Walsh
- York Plasma Institute, University of York, YO10 5DQ, UK
| | - Bojana Žegura
- Jožef Stefan International Postgraduate School, Jamova 39, 1000 Ljubljana, Slovenia; National Institute of Biology, Department of Genetic Toxicology and Cancer Biology, 1000 Ljubljana, Slovenia
| | - Dimitra Lambropoulou
- Laboratory of Environmental Pollution Control, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece; Center for Interdisciplinary Research and Innovation (CIRI-AUTh), Thessaloniki GR-57001, Greece
| | - Uroš Cvelbar
- Jožef Stefan International Postgraduate School, Jamova 39, 1000 Ljubljana, Slovenia; Laboratory for Gaseous Electronics F6, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | - Ester Heath
- Department of Environmental Sciences O2, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Jamova 39, 1000 Ljubljana, Slovenia.
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5
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Hou Z, Li Y, Zheng M, Liu X, Zhang Q, Wang W. Regioselective oxidation of heterocyclic aromatic hydrocarbons catalyzed by cytochrome P450: A case study of carbazole. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 258:114964. [PMID: 37121081 DOI: 10.1016/j.ecoenv.2023.114964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 04/11/2023] [Accepted: 04/26/2023] [Indexed: 05/22/2023]
Abstract
Recently there are increasing interests in accurately evaluating the health effects of heterocyclic PAHs. However, the activation mechanism and possible metabolites of heterocyclic PAHs catalyzed by human CYP1A1 is still elusive to a great extent. Here, leveraged to high level QM/MM calculations, the corresponding activation pathways of a representative heterocyclic PAHs, carbazole, were systematically explored. The first stage is electrophilic addition or hydrogen abstraction from N-H group. Electrophilic addition was evidenced to be more feasible and regioselectivity at C3 and C4 sites were identified. Correlations between energy barriers and key structural/electrostatic parameters reveal that O-Cα distance and Fe-O-Cα angle are the main origin for the catalytic regioselectivity. Electrophilic addition was determined as the rate-determining step and the subsequent possible reactions include epoxidation, NIH shift (the hydrogen migration from the site of hydroxylation to the adjacent carbon) and proton shuttle. The corresponding products are epoxides, ketones and hydroxylated carbazoles, respectively. The main metabolites (hydroxylated carbazoles) are estimated to be more toxic than carbazole. The regioselectivity of carbazole activated by CYP1A1 is different from the environmental processes (gas and aqueous phase). Collectively, these results will inform the in-depth understanding the metabolic processes of heterocyclic PAHs and aid the accurate evaluation of their health effects.
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Affiliation(s)
- Zexi Hou
- Environment Research Institute, Shandong University, Qingdao 266237, PR China
| | - Yanwei Li
- Environment Research Institute, Shandong University, Qingdao 266237, PR China; Shenzhen Research Institute, Shandong University, Shenzhen 518057, PR China.
| | - Mingna Zheng
- Environment Research Institute, Shandong University, Qingdao 266237, PR China
| | - Xinning Liu
- Environment Research Institute, Shandong University, Qingdao 266237, PR China
| | - Qingzhu Zhang
- Environment Research Institute, Shandong University, Qingdao 266237, PR China
| | - Wenxing Wang
- Environment Research Institute, Shandong University, Qingdao 266237, PR China
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Lambré C, Barat Baviera JM, Bolognesi C, Chesson A, Cocconcelli PS, Crebelli R, Gott DM, Grob K, Lampi E, Mengelers M, Mortensen A, Rivière G, Silano (until 21 December 2020†) V, Steffensen I, Tlustos C, Vernis L, Zorn H, Batke M, Bignami M, Corsini E, FitzGerald R, Gundert‐Remy U, Halldorsson T, Hart A, Ntzani E, Scanziani E, Schroeder H, Ulbrich B, Waalkens‐Berendsen D, Woelfle D, Al Harraq Z, Baert K, Carfì M, Castoldi AF, Croera C, Van Loveren H. Re-evaluation of the risks to public health related to the presence of bisphenol A (BPA) in foodstuffs. EFSA J 2023; 21:e06857. [PMID: 37089179 PMCID: PMC10113887 DOI: 10.2903/j.efsa.2023.6857] [Citation(s) in RCA: 31] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023] Open
Abstract
In 2015, EFSA established a temporary tolerable daily intake (t-TDI) for BPA of 4 μg/kg body weight (bw) per day. In 2016, the European Commission mandated EFSA to re-evaluate the risks to public health from the presence of BPA in foodstuffs and to establish a tolerable daily intake (TDI). For this re-evaluation, a pre-established protocol was used that had undergone public consultation. The CEP Panel concluded that it is Unlikely to Very Unlikely that BPA presents a genotoxic hazard through a direct mechanism. Taking into consideration the evidence from animal data and support from human observational studies, the immune system was identified as most sensitive to BPA exposure. An effect on Th17 cells in mice was identified as the critical effect; these cells are pivotal in cellular immune mechanisms and involved in the development of inflammatory conditions, including autoimmunity and lung inflammation. A reference point (RP) of 8.2 ng/kg bw per day, expressed as human equivalent dose, was identified for the critical effect. Uncertainty analysis assessed a probability of 57-73% that the lowest estimated Benchmark Dose (BMD) for other health effects was below the RP based on Th17 cells. In view of this, the CEP Panel judged that an additional uncertainty factor (UF) of 2 was needed for establishing the TDI. Applying an overall UF of 50 to the RP, a TDI of 0.2 ng BPA/kg bw per day was established. Comparison of this TDI with the dietary exposure estimates from the 2015 EFSA opinion showed that both the mean and the 95th percentile dietary exposures in all age groups exceeded the TDI by two to three orders of magnitude. Even considering the uncertainty in the exposure assessment, the exceedance being so large, the CEP Panel concluded that there is a health concern from dietary BPA exposure.
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Wang Y, Chen Y, Chen Y, Luo W, Liu Y. Induction of clastogenesis and gene mutations by carbamazepine (at its therapeutically effective serum levels) in mammalian cells and the dependence on human CYP2B6 enzyme activity. Arch Toxicol 2023; 97:1753-1764. [PMID: 36995427 DOI: 10.1007/s00204-023-03489-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 03/21/2023] [Indexed: 03/31/2023]
Abstract
Carbamazepine (CBZ, an antiepileptic) is metabolized by multiple CYP enzymes to its epoxide and hydroxides; however, whether it is genotoxic remains unclear. In this study, molecular docking (CBZ to CYPs) and cytogenotoxic toxicity assays were employed to investigate the activation of CBZ for mutagenic effects, in various mammalian cell models. Docking results indicated that CBZ was valid as a substrate of human CYP2B6 and 2E1, while not for CYP1A1, 1A2, 1B1 or 3A4. In the Chinese hamster (V79) cell line and its derivatives genetically engineered for the expression of human CYP1A1, 1A2, 1B1, 2E1 or 3A4 CBZ (2.5 ~ 40 μM) did not induce micronucleus, while in human CYP2B6-expressing cells CBZ significantly induced micronucleus formation. In a human hepatoma C3A cell line, which endogenously expressed CYP2B6 twofold higher than in HepG2 cells, CBZ induced micronucleus potently, which was blocked by 1-aminobenzotriazole (inhibitor of CYPs) and ticlopidine (specific CYP2B6 inhibitor). In HepG2 cells CBZ did not induce micronucleus; however, pretreatment of the cells with CICTO (CYP2B6 inducer) led to micronucleus formation by CBZ, while rifampicin (CYP3A4 inducer) or PCB126 (CYP1A inducer) did not change the negative results. Immunofluorescent assay showed that CBZ selectively induced centromere-free micronucleus. Moreover, CBZ induced double-strand DNA breaks (γ-H2AX elevation, by Western blot) and PIG-A gene mutations (by flowcytometry) in C3A (threshold being 5 μM, lower than its therapeutic serum concentrations, 17 ~ 51 μM), with no effects in HepG2 cells. Clearly, CBZ may induce clastogenesis and gene mutations at its therapeutic concentrations, human CYP2B6 being a major activating enzyme.
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Štampar M, Ravnjak T, Domijan AM, Žegura B. Combined Toxic Effects of BPA and Its Two Analogues BPAP and BPC in a 3D HepG2 Cell Model. Molecules 2023; 28:molecules28073085. [PMID: 37049848 PMCID: PMC10095618 DOI: 10.3390/molecules28073085] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/17/2023] [Accepted: 03/28/2023] [Indexed: 03/31/2023] Open
Abstract
Bisphenol A (BPA) is one of the most commonly used substances in the manufacture of various everyday products. Growing concerns about its hazardous properties, including endocrine disruption and genotoxicity, have led to its gradual replacement by presumably safer analogues in manufacturing plastics. The widespread use of BPA and, more recently, its analogues has increased their residues in the environment. However, our knowledge of their toxicological profiles is limited and their combined effects are unknown. In the present study, we investigated the toxic effects caused by single bisphenols and by the combined exposure of BPA and its two analogues, BPAP and BPC, after short (24-h) and prolonged (96-h) exposure in HepG2 spheroids. The results showed that BPA did not reduce cell viability in HepG2 spheroids after 24-h exposure. In contrast, BPAP and BPC affected cell viability in HepG2 spheroids. Both binary mixtures (BPA/BPAP and BPA/BPC) decreased cell viability in a dose-dependent manner, but the significant difference was only observed for the combination of BPA/BPC (both at 40 µM). After 96-h exposure, none of the BPs studied affected cell viability in HepG2 spheroids. Only the combination of BPA/BPAP decreased cell viability in a dose-dependent manner that was significant for the combination of 4 µM BPA and 4 µM BPAP. None of the BPs and their binary mixtures studied affected the surface area and growth of spheroids as measured by planimetry. In addition, all BPs and their binary mixtures studied triggered oxidative stress, as measured by the production of reactive oxygen species and malondialdehyde, at both exposure times. Overall, the results suggest that it is important to study the effects of BPs as single compounds. It is even more important to study the effects of combined exposures, as the combined effects may differ from those induced by single compounds.
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Yu H, Liu Y. Impact of Extended and Combined Exposure of Bisphenol Compounds on Their Chromosome-Damaging Effect─Increased Potency and Shifted Mode of Action. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:498-508. [PMID: 36571243 DOI: 10.1021/acs.est.2c06064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Bisphenol (BP) compounds are important environmental pollutants and endocrine disruptors. BPs are capable of inducing DNA/chromosome breaks (clastogenesis, involved in carcinogenesis), which requires activation by human CYP1A1. We hypothesized that combined BPs and extended (from the standard two-cell cycle) exposure may enhance their genotoxicity via modulating CYP enzymes. In this study, individual and combined BPA/BPF/BPS/BPAF and a human hepatoma (HepG2) cell line were used for testing several genotoxicity end points. Exposing for a two-cell cycle period (48 h), each BP alone (0.625-10 μM) was negative in the micronucleus test, while micronucleus was formed under three- (72 h) and four-cell cycle (96 h) exposure; BP combinations further elevated the potency (with nanomolar thresholds). Immunofluorescence analysis of the centromere with formed micronucleus indicated that 48 h exposure produced centromere-negative micronucleus and phosphorylated histone H2AX (γ-H2AX) (evidencing clastogenesis), while extended (72 and 96 h) exposure formed centromere-positive micronucleus and phosphorylated histone H3 (p-H3) (indicating chromosome loss, i.e., aneugenesis); moreover, 1-aminotriabenzotriazole (CYP inhibitor) selectively blocked the formation of centromere-negative micronucleus and γ-H2AX, without affecting that of centromere-positive micronucleus and p-H3. This study suggests that the genotoxicity of BPs is potentiated by combined and extended exposure, the latter being specific for aneuploidy formation, a CYP activity-independent effect.
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Affiliation(s)
- Hang Yu
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou 510515, China
| | - Yungang Liu
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou 510515, China
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Xie J, Tu H, Chen Y, Chen Z, Yang Z, Liu Y. Triphenyl phosphate induces clastogenic effects potently in mammalian cells, human CYP1A2 and 2E1 being major activating enzymes. Chem Biol Interact 2023; 369:110259. [PMID: 36372259 DOI: 10.1016/j.cbi.2022.110259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 10/31/2022] [Accepted: 11/07/2022] [Indexed: 11/11/2022]
Abstract
As a new-type flame retardant and toxic substance, triphenyl phosphate (TPP) is a ubiquitous pollutant present even in human blood. TPP is transformed by human CYP enzymes to oxidized/dealkylated metabolites. The impact of TPP metabolism on its toxicity, however, remains unclear. In this study, the genotoxicity of TPP in several mammalian cell lines and its relevance to CYP/sulfortransferase (SULT) activities were investigated. The results indicated that TPP induced micronucleus formation at ≥1 μM concentrations in a human hepatoma (C3A, endogenous CYPs being substantial) cell line, which was abolished by 1-aminobenzotriazole (CYPs inhibitor). In cell line HepG2 (parental to C3A with lower CYP expression) TPP was inactive up to 10 μM, while pretreatment with ethanol (CYP2E1 inducer), PCB 126 (CYP1A inducer), or rifampicin (CYP3A inducer) led to micronucleus formation by TPP. In V79-Mz and V79-derived cells expressing human CYP1A1 TPP was inactive (up to 32 μM), and in cells expressing human CYP1B1, 2B6 and 3A4 it induced micronucleus weakly (positive only at 32 μM). However, TPP induced micronucleus potently in V79-derived cells expressing human CYP1A2, while this effect was drastically reduced by human SULT1A1 co-expression; likewise, TPP was inactive in cells expressing both human CYP2E1 and SULT1A1, but became positive with pentachlorophenol (inhibitor of SULT1) co-exposure. Moreover, in C3A cells TPP selectively induced centromere-free micronucleus (immunofluorescent assay), and TPP increased γ-H2AX (by Western blot, indicating double-strand DNA breaks). In conclusion, this study suggests that TPP is potently clastogenic, human CYP1A2 and 2E1 being major activating enzymes while SULT1A1 involved in detoxification.
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Affiliation(s)
- Jiayi Xie
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China
| | - Hongwei Tu
- Guangdong Provincial Center for Disease Control and Prevention, Qunxian Road, Panyu District, Guangzhou, 511430, China
| | - Yijing Chen
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China
| | - Zhihong Chen
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China
| | - Zongying Yang
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China
| | - Yungang Liu
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China.
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11
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Sendra M, Štampar M, Fras K, Novoa B, Figueras A, Žegura B. Adverse (geno)toxic effects of bisphenol A and its analogues in hepatic 3D cell model. ENVIRONMENT INTERNATIONAL 2023; 171:107721. [PMID: 36580735 PMCID: PMC9875311 DOI: 10.1016/j.envint.2022.107721] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/05/2022] [Accepted: 12/23/2022] [Indexed: 05/10/2023]
Abstract
Bisphenol A (BPA) is one of the most widely used and versatile chemical compounds in polymer additives and epoxy resins for manufacturing a range of products for human applications. It is known as endocrine disruptor, however, there is growing evidence that it is genotoxic. Because of its adverse effects, the European Union has restricted its use to protect human health and the environment. As a result, the industry has begun developing BPA analogues, but there are not yet sufficient toxicity data to claim that they are safe. We investigated the adverse toxic effects of BPA and its analogues (BPS, BPAP, BPAF, BPFL, and BPC) with emphasis on their cytotoxic and genotoxic activities after short (24-h) and prolonged (96-h) exposure in in vitro hepatic three-dimensional cell model developed from HepG2 cells. The results showed that BPFL and BPC (formed by an additional ring system) were the most cytotoxic analogues that affected cell viability, spheroid surface area and morphology, cell proliferation, and apoptotic cell death. BPA, BPAP, and BPAF induced DNA double-strand break formation (γH2AX assay), whereas BPAF and BPC increased the percentage of p-H3-positive cells, indicating their aneugenic activity. All BPs induced DNA single-strand break formation (comet assay), with BPAP (≥0.1 μM) being the most effective and BPA and BPC the least effective (≥1 μM) under conditions applied. The results indicate that not all of the analogues studied are safer alternatives to BPA and thus more in-depth research is urgently needed to adequately evaluate the risks of BPA analogues and assess their safety for humans.
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Affiliation(s)
- Marta Sendra
- Department of Biotechnology and Food Science, Faculty of Sciences, University of Burgos, Plaza Misael Bañuelos, 09001 Burgos, Spain; International Research Center in Critical Raw Materials-ICCRAM, Universidad de Burgos, Plaza Misael Bañuelos s/n, 09001 Burgos, Spain.
| | - Martina Štampar
- National Institute of Biology, Department of Genetic Toxicology and Cancer Biology, 1000 Ljubljana, Slovenia.
| | - Katarina Fras
- National Institute of Biology, Department of Genetic Toxicology and Cancer Biology, 1000 Ljubljana, Slovenia.
| | - Beatriz Novoa
- Immunology and Genomics Group, Instituto de Investigaciones Marinas (IIM), Consejo Superior de Investigaciones Científicas (CSIC), Vigo, Spain.
| | - Antonio Figueras
- Immunology and Genomics Group, Instituto de Investigaciones Marinas (IIM), Consejo Superior de Investigaciones Científicas (CSIC), Vigo, Spain.
| | - Bojana Žegura
- National Institute of Biology, Department of Genetic Toxicology and Cancer Biology, 1000 Ljubljana, Slovenia; Jozef Stefan International Postgraduate School, 1000 Ljubljana, Slovenia.
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12
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Chen C, Zhang D, Yuan A, Shen J, Wang L, Wang SL. A novel approach to predict the comprehensive EROD potency: Mechanism-based curve fitting of CYP1A1 activity by PAHs. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 843:157052. [PMID: 35787903 DOI: 10.1016/j.scitotenv.2022.157052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/24/2022] [Accepted: 06/25/2022] [Indexed: 06/15/2023]
Abstract
Cytochrome P450 1A1 (CYP1A1) plays critical roles in polycyclic aromatic hydrocarbon (PAH) toxicity, including DNA adduction and ROS generation. Therefore, CYP1A1 activity quantified by the 7-ethoxyresorufin-O-deethylase (EROD) assay (named EROD potency) has been considered a typical biomarker of PAH exposure and toxicity. The EROD dose-response curve always presents a biphasic style, increasing at low concentrations and decreasing at high concentrations of PAHs, but relative effect potency (REP) commonly used in PAH risk assessment is only involved in the increasing phase. In this study, a full bell-shaped EROD curve fitting formula Eq. (1) was obtained by considering both CYP1A1 mRNA induction and enzyme inhibition to completely assess the EROD potency of PAHs. Correspondingly, in silico models of QSAR and docking methods successfully predicted the full EROD curves of PAHs, and the structure-activity relationship indicated that PAHs with heavy molecular weight and large diameter showed stronger EROD potency. Further EROD potency with predicted curve parameters (EC50,ind and area index) was confirmed by the reported REP (R2 = 0.697-0.977) and experimental data from human and mouse cells (R2 = 0.700-0.804). This study provides a novel curve fitting for the EROD dose-response relationship and a prediction model for PAH EROD potency.
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Affiliation(s)
- Chao Chen
- Key Laboratory of Modern Toxicology of Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, PR China
| | - Di Zhang
- Key Laboratory of Modern Toxicology of Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, PR China
| | - Anjie Yuan
- Key Laboratory of Modern Toxicology of Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, PR China
| | - Jiemiao Shen
- Key Laboratory of Modern Toxicology of Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, PR China
| | - Li Wang
- Key Laboratory of Modern Toxicology of Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, PR China
| | - Shou-Lin Wang
- Key Laboratory of Modern Toxicology of Ministry of Education, Center for Global Health, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, PR China; State Key Laboratory of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211166, PR China.
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13
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Kuang H, Zhou W, Zeng Y, Xu D, Zhu W, Lin S, Fan R. Dose makes poison: Insights into the neurotoxicity of perinatal and juvenile exposure to environmental doses of 16 priority-controlled PAHs. CHEMOSPHERE 2022; 298:134201. [PMID: 35257710 DOI: 10.1016/j.chemosphere.2022.134201] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 02/18/2022] [Accepted: 03/02/2022] [Indexed: 06/14/2023]
Abstract
Whether chronic exposure to environmental doses of polycyclic aromatic hydrocarbons (PAHs) can lead to neurotoxic effects is still unclear. Hence, the neurotoxic effects of perinatal and juvenile exposure to 16 priority-controlled PAHs were investigated. The mice were treated with 0, 0.5, 18.75, 50, 1875 μg/kg/day of PAHs corresponding to various population exposure concentrations from gestation to postnatal day 60. Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) and hippocampal and cortical neurotransmitter levels were determined using liquid chromatography-tandem mass spectrometry. Typical indicators or outcome of neurotoxicity, including, spatial learning and memory ability, hippocampal long-term potentiation (LTP) and dendritic spine density were evaluated via Morris water maze tests, electrophysiological experiments and Golgi-Cox assays, respectively. The results showed that exposure to different levels of PAH could not increase oxidative DNA damage level. Mice exposed to 0.5, 50 and 1875 μg/kg/day PAHs had significantly longer escape latency than the control group only on the 1st day (p < 0.05). The number of platform crossings and the time spent in target quadrant were similar between the control and the PAHs-exposed mice. Compared with the control mice, only those exposed to 50 μg/kg/day PAHs had significantly lower LTP in hippocampal CA1 region and dendritic spine density in hippocampal DG region (p < 0.05). Except for serotonin, no significant difference in hippocampal and cortical neurotransmitter concentrations was observed between the control and PAHs-exposed groups. Taken together, perinatal and juvenile exposure to environmental doses of PAHs had no profound effect on spatial learning and memory abilities, hippocampal LTP, dendritic spines density, and neurotransmitter levels. These unexpected findings were quite different from previous in vivo studies which commonly used 2-3 orders of magnitude higher PAHs doses to treat animals. Thus, the environmental dose is a crucial reference for future toxicological research to reveal the actual toxic mechanisms and human health effects of PAHs exposure.
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Affiliation(s)
- Hongxuan Kuang
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring and Guangdong Provincial Engineering Technology Research Center for Drug and Food Biological Resources Processing and Comprehensive Utilization, School of Life Sciences, South China Normal University, Guangzhou, 510631, China; State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, Ministry of Ecology and Environment, South China Institute of Environmental Sciences, Guangzhou, 510655, China
| | - Wenji Zhou
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring and Guangdong Provincial Engineering Technology Research Center for Drug and Food Biological Resources Processing and Comprehensive Utilization, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Yingwei Zeng
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring and Guangdong Provincial Engineering Technology Research Center for Drug and Food Biological Resources Processing and Comprehensive Utilization, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Da Xu
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring and Guangdong Provincial Engineering Technology Research Center for Drug and Food Biological Resources Processing and Comprehensive Utilization, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Wanqi Zhu
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring and Guangdong Provincial Engineering Technology Research Center for Drug and Food Biological Resources Processing and Comprehensive Utilization, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Shengjie Lin
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring and Guangdong Provincial Engineering Technology Research Center for Drug and Food Biological Resources Processing and Comprehensive Utilization, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Ruifang Fan
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring and Guangdong Provincial Engineering Technology Research Center for Drug and Food Biological Resources Processing and Comprehensive Utilization, School of Life Sciences, South China Normal University, Guangzhou, 510631, China.
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14
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Wang JY, Li JX, Ning J, Huo XK, Yu ZL, Tian Y, Zhang BJ, Wang Y, Sa D, Li YC, Lv X, Ma XC. Human cytochrome P450 3A-mediated two-step oxidation metabolism of dimethomorph: Implications in the mechanism-based enzyme inactivation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 822:153585. [PMID: 35121040 DOI: 10.1016/j.scitotenv.2022.153585] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 01/27/2022] [Accepted: 01/27/2022] [Indexed: 06/14/2023]
Abstract
Dimethomorph (DMM), an effective and broad-spectrum fungicide applied in agriculture, is toxic to environments and living organisms due to the hazardous nature of its toxic residues. This study aims to investigate the human cytochrome P450 enzyme (CYP)-mediated oxidative metabolism of DMM by combining experimental and computational approaches. Dimethomorph was metabolized predominantly through a two-step oxidation process mediated by CYPs, and CYP3A was identified as the major contributor to DMM sequential oxidative metabolism. Meanwhile, DMM elicited the mechanism-based inactivation (MBI) of CYP3A in a suicide manner, and the iminium ion and epoxide reactive intermediates generated in DMM metabolism were identified as the culprits of MBI. Furthermore, three common pesticides, prochloraz (PCZ), difenoconazole (DFZ) and chlorothalonil (CTL), could significantly inhibit CYP3A-mediated DMM metabolism, and consequently trigger elevated exposure to DMM in vivo. Computational studies elucidated that the differentiation effects in charge distribution and the interaction pattern played crucial roles in DMM-induced MBI of CYP3A4 during sequential oxidative metabolism. Collectively, this study provided a global view of the two-step metabolic activation process of DMM mediated by CYP3A, which was beneficial for elucidating the environmental fate and toxicological mechanism of DMM in humans from a new perspective.
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Affiliation(s)
- Jia-Yue Wang
- College of Integrative Medicine, Dalian Medical University, Dalian 116000, Liaoning, China; Pharmaceutical Research Center, Second Affiliated Hospital, Dalian Medical University, Dalian 116000, Liaoning, China; Department of Pharmacy, Peking University Shenzhen Hospital, Shenzhen 518036, China
| | - Jing-Xin Li
- College of Integrative Medicine, Dalian Medical University, Dalian 116000, Liaoning, China; School of Public Health, Dalian Medical University, Dalian 116000, Liaoning, China
| | - Jing Ning
- College of Integrative Medicine, Dalian Medical University, Dalian 116000, Liaoning, China
| | - Xiao-Kui Huo
- Pharmaceutical Research Center, Second Affiliated Hospital, Dalian Medical University, Dalian 116000, Liaoning, China
| | - Zhen-Long Yu
- College of Integrative Medicine, Dalian Medical University, Dalian 116000, Liaoning, China
| | - Yan Tian
- College of Integrative Medicine, Dalian Medical University, Dalian 116000, Liaoning, China
| | - Bao-Jing Zhang
- College of Integrative Medicine, Dalian Medical University, Dalian 116000, Liaoning, China
| | - Yan Wang
- College of Integrative Medicine, Dalian Medical University, Dalian 116000, Liaoning, China
| | - Deng Sa
- College of Integrative Medicine, Dalian Medical University, Dalian 116000, Liaoning, China
| | - Ya-Chen Li
- School of Public Health, Dalian Medical University, Dalian 116000, Liaoning, China
| | - Xia Lv
- College of Integrative Medicine, Dalian Medical University, Dalian 116000, Liaoning, China.
| | - Xiao-Chi Ma
- Pharmaceutical Research Center, Second Affiliated Hospital, Dalian Medical University, Dalian 116000, Liaoning, China.
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15
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Yang Z, Yu H, Tu H, Chen Z, Hu K, Jia H, Liu Y. Influence of aryl hydrocarbon receptor and sulfotransferase 1A1 on bisphenol AF-induced clastogenesis in human hepatoma cells. Toxicology 2022; 471:153175. [PMID: 35395335 DOI: 10.1016/j.tox.2022.153175] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/11/2022] [Accepted: 04/01/2022] [Indexed: 12/11/2022]
Abstract
Bisphenol compounds (BPs) are ubiquitously existing pollutants. Recent evidence shows that they may be activated by human CYP1A1 for clastogenic effects; however, factors that influence/mediate CYP1A1-activated 4,4'-(hexafluoroisopropylidene)diphenol (BPAF) toxicity, particularly the aryl hydrocarbon receptor (AhR), sulfotransferase (SULT) 1A1 [known to conjugate 2,2-bis(4-hydroxyphenol)-propane (BPA)] and reactive oxygen species (ROS), remain unclear. In this study, a human hepatoma (HepG2) cell line was genetically engineered for the expression of human CYP1A1 and SULT1A1, producing HepG2-hCYP1A1 and HepG2-hSULT1A1, respectively. They were used in the micronucleus test and γ-H2AX analysis (Western blot) (indicating double-strand DNA breaks) with BPAF; the role of AhR in mediating BPAF toxicity was investigated by coexposure of AhR modulators in HepG2 and its derivative C3A (with no genetic modifications but enhanced CYP expression). The results indicated induction of micronuclei by BPAF (≥ 2.5 µM, for 2-cell cycle) in HepG2-hCYP1A1 and C3A, while inactive in HepG2 and HepG2-hSULT1A1; however, BPAF induced micronuclei in HepG2 pretreated with 3,3',4,4',5-pentachlorobiphenyl (PCB126, AhR activator), and BAY-218 (AhR inhibitor) blocked the effect of BPAF in C3A. In HepG2-hCYP1A1 BPAF selectively induced centromere-free micronuclei (immunofluorescent assay) and double-strand DNA breaks. In HepG2 cells receiving conditional medium from BPAF-HepG2-hCYP1A1 incubation micronuclei were formed, while negative in HepG2-hSULT1A1. Finally, the intracellular levels of ROS, superoxide dismutase and reduced glutathione in C3A and HepG2-hCYP1A1 exposed to BPAF were all moderately increased, while unchanged in HepG2 cells. In conclusion, like other BPs BPAF is activated by human CYP1A1 for potent clastogenicity, and this effect is enhanced by AhR while alleviated by SULT1A1.
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Affiliation(s)
- Zongying Yang
- Department of Toxicology, School of Public Health, Southern Medical University (Guangdong Provincial Key Laboratory of Tropical Disease Research), 1023 S. Shatai Road, Guangzhou 510515, China
| | - Hang Yu
- Department of Toxicology, School of Public Health, Southern Medical University (Guangdong Provincial Key Laboratory of Tropical Disease Research), 1023 S. Shatai Road, Guangzhou 510515, China
| | - Hongwei Tu
- Guangdong Provincial Center for Disease Control and Prevention, Qunxian Road, Panyu District, Guangzhou 511430, China
| | - Zhihong Chen
- Department of Toxicology, School of Public Health, Southern Medical University (Guangdong Provincial Key Laboratory of Tropical Disease Research), 1023 S. Shatai Road, Guangzhou 510515, China
| | - Keqi Hu
- Department of Toxicology, School of Public Health, Southern Medical University (Guangdong Provincial Key Laboratory of Tropical Disease Research), 1023 S. Shatai Road, Guangzhou 510515, China
| | - Hansi Jia
- The Eighth Affiliated Hospital, Sun Yat-sen University, 3025 Shennan Middle Road, Futian District, Shenzhen 518033, China.
| | - Yungang Liu
- Department of Toxicology, School of Public Health, Southern Medical University (Guangdong Provincial Key Laboratory of Tropical Disease Research), 1023 S. Shatai Road, Guangzhou 510515, China.
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16
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Song M, Wang Y, Chen Z, Gao H, Yang Z, Yu H, Liu Y. Human CYP enzyme-activated genotoxicity of 2,2',4,4'-tetrabromobiphenyl ether in mammalian cells. CHEMOSPHERE 2022; 291:132784. [PMID: 34742755 DOI: 10.1016/j.chemosphere.2021.132784] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 10/29/2021] [Accepted: 11/02/2021] [Indexed: 06/13/2023]
Abstract
Polybrominated biphenyl ethers (PBDEs) are a group of persistent organic pollutants with endocrine-disrupting, neurotoxic, tumorigenic and DNA-damaging activities. They are hydroxylated by human liver microsomal CYP enzymes, however, their mutagenicity remains unknown. In this study, 2,2',4,4'-tetrabromobiphenyl ether (BDE-47, relatively abundant in human tissues) was investigated for micronuclei induction and DNA damage in mammalian cells. The results indicated that BDE-47 up to 80 μM under a 6 h/18 h (exposure/recovery, covering 2 cell cycles) regime did not induce micronuclei in V79-Mz and V79-derived cell lines expressing human CYP1A1 or 1A2, while it was moderately positive in human CYP2B6-, 2E1-and 3A4-expressing cell lines (V79-hCYP2B6, V79-hCYP2E1-hSULT1A1 and V79-hCYP3A4-hOR, respectively). Following 24 h exposure, BDE-47 induced micronuclei in V79-hCYP2E1-hSULT1A1 and V79-hCYP3A4 cells at increased potencies. In the human hepatoma (HepG2) cells BDE-47 (48 h exposure) was inactive up to 40 μM, however, pretreatment of the cells with ethanol (0.2%, v:v, inducer of CYP2E1) or rifampicin (10 μM, inducer of CYP3A4) led to significant micronuclei formation by BDE-47; pretreatment with bisphenol AF (100 nM) also potentiated BDE-47-induced micronuclei formation (which was blocked by a CYP2E1 inhibitor trans-1,2-dichloroethylene or a CYP3A inhibitor (ketoconazole). Immunofluorescent staining of centromere protein B with the micronuclei formed by BDE-47 in HepG2 cells pretreated with ethanol or rifampicin demonstrated selective formation of centromere-containing micronuclei. The increased phosphorylation of both histones H2AX and H3 in HepG2 by BDE-47 also indicated an aneugenic potential. Therefore, this study suggests that BDE-47 is an aneugen activated by several human CYP enzymes.
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Affiliation(s)
- Meiqi Song
- Department of Toxicology, School of Public Health, Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China
| | - Yujian Wang
- Department of Toxicology, School of Public Health, Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China
| | - Zhihong Chen
- Department of Toxicology, School of Public Health, Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China
| | - Hongbin Gao
- Department of Toxicology, School of Public Health, Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China; Guangdong Laboratory Animals Monitoring Institute, Guangdong Provincial Key Laboratory of Laboratory Animals, Guangzhou, 510663, China
| | - Zongying Yang
- Department of Toxicology, School of Public Health, Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China
| | - Hang Yu
- Department of Toxicology, School of Public Health, Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China
| | - Yungang Liu
- Department of Toxicology, School of Public Health, Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China.
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17
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Lv X, Li JX, Wang JY, Tian XG, Feng L, Sun CP, Ning J, Wang C, Zhao WY, Li YC, Ma XC. Regioselective hydroxylation of carbendazim by mammalian cytochrome P450: A combined experimental and computational study. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 293:118523. [PMID: 34793912 DOI: 10.1016/j.envpol.2021.118523] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/11/2021] [Accepted: 11/14/2021] [Indexed: 06/13/2023]
Abstract
Carbendazim (CBZ), a broad-spectrum pesticide frequently detected in fruits and vegetables, could trigger potential toxic risks to mammals. To facilitate the assessment of health risks, this study aimed to characterize the cytochrome P450 (CYPs)-mediated metabolism profiles of CBZ by a combined experimental and computational study. Our results demonstrated that CYPs-mediated region-selective hydroxylation was a major metabolism pathway for CBZ in liver microsomes from various species including rat, mouse, minipig, dog, rabbit, guinea pig, monkey, cow and human, and the metabolite was biosynthesized and well-characterized as 6-OH-CBZ. CYP1A displayed a predominant role in the region-selective hydroxylation of CBZ that could attenuate its toxicity through converting it into a less toxic metabolite. Meanwhile, five other common pesticides including chlorpyrifos-methyl, prochloraz, chlorfenapyr, chlorpyrifos, and chlorothalonil could significantly inhibit the region-selective hydroxylation of CBZ, and consequently remarkably increased CBZ exposure in vivo. Furthermore, computational study clarified the important contribution of the key amino acid residues Ser122, and Asp313 in CYP1A1, as well as Asp320 in CYP1A2 to the hydroxylation of CBZ through hydrogen bonds. These results would provide some useful information for the metabolic profiles of CBZ by mammalian CYPs, and shed new insights into CYP1A-mediated metabolic detoxification of CBZ and its health risk assessment.
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Affiliation(s)
- Xia Lv
- Institute of Precision Medicine and Transformation, Second Affiliated Hospital, Dalian Medical University, Dalian, 116023, China; College of Integrative Medicine, School of Public Health, College of Pharmacy, Dalian Medical University, Dalian, 116000, Liaoning, China
| | - Jing-Xin Li
- Institute of Precision Medicine and Transformation, Second Affiliated Hospital, Dalian Medical University, Dalian, 116023, China; College of Integrative Medicine, School of Public Health, College of Pharmacy, Dalian Medical University, Dalian, 116000, Liaoning, China
| | - Jia-Yue Wang
- Institute of Precision Medicine and Transformation, Second Affiliated Hospital, Dalian Medical University, Dalian, 116023, China
| | - Xiang-Ge Tian
- College of Integrative Medicine, School of Public Health, College of Pharmacy, Dalian Medical University, Dalian, 116000, Liaoning, China
| | - Lei Feng
- Institute of Precision Medicine and Transformation, Second Affiliated Hospital, Dalian Medical University, Dalian, 116023, China
| | - Cheng-Peng Sun
- College of Integrative Medicine, School of Public Health, College of Pharmacy, Dalian Medical University, Dalian, 116000, Liaoning, China
| | - Jing Ning
- College of Integrative Medicine, School of Public Health, College of Pharmacy, Dalian Medical University, Dalian, 116000, Liaoning, China
| | - Chao Wang
- College of Integrative Medicine, School of Public Health, College of Pharmacy, Dalian Medical University, Dalian, 116000, Liaoning, China
| | - Wen-Yu Zhao
- College of Integrative Medicine, School of Public Health, College of Pharmacy, Dalian Medical University, Dalian, 116000, Liaoning, China
| | - Ya-Chen Li
- College of Integrative Medicine, School of Public Health, College of Pharmacy, Dalian Medical University, Dalian, 116000, Liaoning, China
| | - Xiao-Chi Ma
- Institute of Precision Medicine and Transformation, Second Affiliated Hospital, Dalian Medical University, Dalian, 116023, China; College of Integrative Medicine, School of Public Health, College of Pharmacy, Dalian Medical University, Dalian, 116000, Liaoning, China.
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18
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Chen Z, Xie J, Li Q, Hu K, Yang Z, Yu H, Liu Y. Human CYP enzyme-activated clastogenicity of 2-ethylhexyl diphenyl phosphate (a flame retardant) in mammalian cells. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 285:117527. [PMID: 34380225 DOI: 10.1016/j.envpol.2021.117527] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 05/30/2021] [Accepted: 06/01/2021] [Indexed: 06/13/2023]
Abstract
2-Ethylhexyl diphenyl phosphate (EHDPP) is a common flame retardant and environmental pollutant, exposing humans with endocrinal disrupting potentials. Its mutagenicity, especially following metabolism, remains unclear. In this study, molecular docking analysis indicated that EHDPP was a potential substrate for several human CYP enzymes except for CYP1A1. Among V79-derived cell lines genetically engineered for the expression of each CYP, EHDPP (6 h exposure/18 h recovery) did not induce micronuclei in the V79 or V79-derived cells expressing human CYP1A1, however, it was positive in V79-derived cell lines expressing human CYP2E1, 3A4, and 2B6. In a human hepatoma (HepG2) cell line, EHDPP (48 h exposure) moderately induced micronuclei, which was blocked by 1-aminobenzotriazole (ABT, 60 μM, inhibitor of CYPs); pretreating HepG2 cells with bisphenol AF, another organic pollutant as inducer of CYPs (0.1 μM for 16 h), significantly potentiated micronuclei formation by EHDPP, threshold being decreased from 10 to 1.25 μM. This effect was blocked by ABT, drastically reduced by ketoconazole (inhibiting CYP3A expression/activity), and moderately inhibited by trans-1,2-dichloroethylene (selective CYP2E1 inhibitor). Immunofluorescent centromere protein B staining indicated that EHDPP-induced micronuclei in V79-derived cell lines expressing human CYP2E1 and 3A4 were predominantly centromere-negative, and that in HepG2 cells pretreated with bisphenol AF (for inducing multiple CYPs) were purely centromere-negative. In bisphenol AF-pretreated HepG2 cells EHDPP potently induced DNA breaks, as indicated by the comet assay and Western blot analysis of γ-H2AX. In conclusion, our study suggests that EHDPP is potently clastogenic, following activation by several human CYP enzymes, CYP3A4 being a major one.
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Affiliation(s)
- Zhihong Chen
- Department of Toxicology, School of Public Health, (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China
| | - Jiayi Xie
- Department of Toxicology, School of Public Health, (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China
| | - Qing Li
- Department of Dietetics, Nanfang Hospital, Southern Medical University, 1838 N. Guangzhou Avenue, Guangzhou, 510515, China
| | - Keqi Hu
- Department of Toxicology, School of Public Health, (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China
| | - Zongying Yang
- Department of Toxicology, School of Public Health, (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China
| | - Hang Yu
- Department of Toxicology, School of Public Health, (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China
| | - Yungang Liu
- Department of Toxicology, School of Public Health, (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou, 510515, China.
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19
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Yu H, Song M, Hu K, Wang Y, Fan R, Yang Z, Glatt H, Braeuning A, Liu Y. Influence of Bisphenol Compounds at Nanomolar Concentrations on Chromosome Damage Induced by Metabolically Activated Carcinogens in HepG2 Cells. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:10001-10011. [PMID: 34241998 DOI: 10.1021/acs.est.1c02189] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Bisphenol (BP) compounds are endocrine-disrupting organic pollutants. BPs may increase the messenger RNA (mRNA) transcripts of nuclear receptors (NRs) regulating the expression of xenobiotic-metabolizing cytochrome P450 (CYP) enzymes. Their impact on the genotoxicity of metabolically activated carcinogens, however, remains unknown. In this study, effects of the bisphenols A, F, S, and AF on the expression of the aryl hydrocarbon receptor (AhR), the pregnane X receptor (PXR), the constitutive androstane receptor, and individual xenobiotic-metabolizing CYP enzymes in a human hepatoma (HepG2) cell line were investigated, along with in silico binding studies of BPs to each receptor. The results indicated that each BP at 1 to 100 nM concentrations increased the mRNA transcripts and protein levels of AhR, PXR, CYP1A1, 1A2, 1B1, 2E1, and 3A4. The predicted affinities of the BPs for binding AhR were comparable to those of potent agonists. Pretreatment of HepG2 cells with each BP potentiated the induction of micronuclei by benzo[a]pyrene, aflatoxin B1, benzene, and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone; this effect was abolished/reduced by inhibitors of NRs and/or CYPs. Our study suggests that BPs at human exposure levels may aggravate chromosome damage by several impactful carcinogens in human cells by inducing relevant CYP enzymes, mostly via NR modulation.
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Affiliation(s)
- Hang Yu
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou 510515, China
| | - Meiqi Song
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou 510515, China
| | - Keqi Hu
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou 510515, China
| | - Yujian Wang
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou 510515, China
| | - Ruifang Fan
- School of Life Science, South China Normal University, Guangzhou 510631, China
| | - Zongying Yang
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou 510515, China
| | - Hansruedi Glatt
- Department of Nutritional Toxicology, German Institute of Human Nutrition (DIfE), Arthur-Scheunert-Allee 114-116, Nuthetal D-14558, Germany
- Department of Food Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Straße 8-10, Berlin D-10589, Germany
| | - Albert Braeuning
- Department of Food Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Straße 8-10, Berlin D-10589, Germany
| | - Yungang Liu
- Department of Toxicology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, 1023 S. Shatai Road, Guangzhou 510515, China
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