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Li X, Bullert AJ, Han W, Yang W, Zhang QY, Ding X, Lehmler HJ. Enantiomeric Fractions Reveal Differences in the Atropselective Disposition of 2,2',3,5',6-Pentachlorobiphenyl (PCB 95) in Wildtype, Cyp2abfgs-Null, and CYP2A6-Humanized Mice. Chem Res Toxicol 2023; 36:1386-1397. [PMID: 37467352 PMCID: PMC10445290 DOI: 10.1021/acs.chemrestox.3c00128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Indexed: 07/21/2023]
Abstract
Polychlorinated biphenyls (PCBs) are environmental contaminants that can cause neurotoxicity. PCBs, such as PCB 95 (2,2',3,5',6-pentachlorobiphenyl), can be metabolized by cytochrome P450 enzymes into neurotoxic metabolites. To better understand how the metabolism of PCB 95 affects neurotoxic outcomes, we conducted a study on the disposition of PCB 95 in transgenic mouse models. The mice were given a single oral dose of PCB 95 (1.0 mg/kg) and were euthanized 24 h later for analysis. PCB 95 levels were highest in adipose tissue, followed by the liver, brain, and blood. Adipose tissue levels were significantly higher in wild-type (WT) mice than in Cyp2abfgs-null (KO) or CYP2A6-transgenic (KI) mice. We also observed genotype-dependent differences in the enrichment of aS-PCB 95 in female mice, with a less pronounced enrichment in KO than WT and KI mice. Ten hydroxylated PCB 95 metabolites were detected in blood and tissue across all exposure groups. The metabolite profiles differed across tissues, while sex and genotype-dependent differences were less pronounced. Total OH-PCB levels were highest in the blood, followed by the liver, adipose tissue, and brain. Total OH-PCB blood levels were lower in KO than in WT mice, while the opposite trend was observed in the liver. In male mice, total OH-PCB metabolite levels were significantly lower in KI than in WT mice in blood and the liver, while the opposite trend was observed in female mice. In conclusion, the study highlights the differences in the atropselective disposition of PCB 95 and its metabolites in different types of mice, demonstrating the usefulness of these transgenic mouse models for characterizing the role of PCB metabolism in PCB neurotoxicity.
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Affiliation(s)
- Xueshu Li
- Department
of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, Iowa 52242, United States
| | - Amanda J. Bullert
- Department
of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, Iowa 52242, United States
- Interdisciplinary
Graduate Program in Neuroscience, University
of Iowa, Iowa City, Iowa 52242, United States
| | - Weiguo Han
- Department
of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona 85721, United States
| | - Weizhu Yang
- Department
of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona 85721, United States
| | - Qing-Yu Zhang
- Department
of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona 85721, United States
| | - Xinxin Ding
- Department
of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona 85721, United States
| | - Hans-Joachim Lehmler
- Department
of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, Iowa 52242, United States
- Interdisciplinary
Graduate Program in Neuroscience, University
of Iowa, Iowa City, Iowa 52242, United States
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2
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Ito T, Miwa C, Haga Y, Kubo M, Itoh T, Yamamoto K, Mise S, Goto E, Tsuzuki H, Matsumura C, Nakano T, Inui H. Enantioselective metabolism of chiral polychlorinated biphenyl 2,2',3,4,4',5',6-Heptachlorobiphenyl (CB183) by human and rat CYP2B subfamilies. CHEMOSPHERE 2022; 308:136349. [PMID: 36084836 DOI: 10.1016/j.chemosphere.2022.136349] [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: 02/27/2022] [Revised: 08/10/2022] [Accepted: 09/02/2022] [Indexed: 06/15/2023]
Abstract
Chiral polychlorinated biphenyls (PCBs) have atropisomers that have different axial chiralities and exist as racemic mixtures. However, biochemical processes often result in the unequal accumulation of these atropisomers in organisms. This phenomenon leads to enantiospecific toxicity enhancement or reduction because either of the atropisomers mainly affects toxicity expression. Enantioselective accumulation is caused by cytochrome P450 (CYP, P450) monooxygenases, especially the CYP2B subfamilies. Therefore, this study investigates the metabolism of a chiral PCB in vitro. Both atropisomers isolated from racemic 2,2',3,4,4',5',6-heptachlorobiphenyl (CB183) were metabolized by human CYP2B6, but not rat CYP2B1. This may be due to the difference in the size of the substrate-binding cavities of CYP2B6 and CYP2B1. The stable accommodation of (-)-CB183 in the cavity without any steric hindrance explained the preferential metabolism of (-)-CB183 compared to (+)-CB183. Two hydroxylated metabolites, 3'-OH-CB183 and 5-OH-CB183, were identified. The docking study showed that the 3'-position of the trichlorophenyl ring closely approaches the heme of CYP2B6. To our knowledge, this is the first study to elucidate the structural basis of chiral PCB metabolism by P450 isozymes. These results will help promote the precise toxicity evaluation of chiral PCBs and provide an explanation of the structural basis of chiral PCB metabolism.
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Affiliation(s)
- Terushi Ito
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Chiharu Miwa
- Faculty of Agriculture, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Yuki Haga
- Hyogo Prefectural Institute of Environmental Sciences, 3-1-18 Yukihiracho, Suma-ku, Kobe, Hyogo, 654-0037, Japan
| | - Makoto Kubo
- Laboratory of Drug Design and Medicinal Chemistry, Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo, 194-8543, Japan
| | - Toshimasa Itoh
- Laboratory of Drug Design and Medicinal Chemistry, Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo, 194-8543, Japan
| | - Keiko Yamamoto
- Laboratory of Drug Design and Medicinal Chemistry, Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo, 194-8543, Japan
| | - Shintaro Mise
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Erika Goto
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Harunobu Tsuzuki
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Chisato Matsumura
- Hyogo Prefectural Institute of Environmental Sciences, 3-1-18 Yukihiracho, Suma-ku, Kobe, Hyogo, 654-0037, Japan
| | - Takeshi Nakano
- Research Center for Environmental Preservation, Osaka University, 2-4 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Hideyuki Inui
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo, 657-8501, Japan; Biosignal Research Center, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe, Hyogo, 657-8501, Japan.
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3
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Abu-Bakar A, Tan BH, Halim H, Ramli S, Pan Y, Ong6 CE. Cytochromes P450: Role in Carcinogenesis and Relevance to Cancers. Curr Drug Metab 2022; 23:355-373. [DOI: 10.2174/1389200223666220328143828] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 12/06/2021] [Accepted: 01/25/2022] [Indexed: 11/22/2022]
Abstract
Abstracts:
Cancer is a leading factor of mortality globally. Cytochrome P450 (CYP) enzymes play a pivotal role in the biotransformation of both endogenous and exogenous compounds. Evidence from numerous epidemiological, animal, and clinical studies points to instrumental role of CYPs in cancer initiation, metastasis, and prevention. Substantial research has found that CYPs are involved in activating different carcinogenic chemicals in the environment, such as polycyclic aromatic hydrocarbons and tobacco-related nitrosamines. Electrophilic intermediates produced from these chemicals can covalently bind to DNA, inducing mutation and cellular transformation that collectively result in cancer development. While bioactivation of procarcinogens and promutagens by CYPs has long been established, the role of CYP-derived endobiotics in carcinogenesis has emerged in recent years. Eicosanoids derived from arachidonic acid via CYP oxidative pathways have been implicated in tumorigenesis, cancer progression and metastasis. The purpose of this review is to update on the current state of knowledge about the cancer molecular mechanism involving CYPs with focus on the biochemical and biotransformation mechanisms in the various CYP-mediated carcinogenesis, and the role of CYP-derived reactive metabolites, from both external and endogenous sources, on cancer growth and tumour formation.
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Affiliation(s)
- A’edah Abu-Bakar
- Product Stewardship and Toxicology, Group Health, Safety, Security and Environment, PETRONAS, Kuala Lumpur, Malaysia
| | - Boon Hooi Tan
- Division of Applied Biomedical Sciences and Biotechnology, International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia
| | - Hasseri Halim
- Faculty of Pharmacy, Universiti Teknologi MARA, Selangor, 42300 Puncak Alam, Selangor, Malaysia
| | - Salfarina Ramli
- Faculty of Pharmacy, Universiti Teknologi MARA, Selangor, 42300 Puncak Alam, Selangor, Malaysia
| | - Yan Pan
- Department of Biomedical Science, University of Nottingham Malaysia Campus, Semenyih, Selangor, Malaysia
| | - Chin Eng Ong6
- School of Pharmacy, International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia
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4
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Chen S, Wu Q, Li X, Li D, Mei N, Ning B, Puig M, Ren Z, Tolleson WH, Guo L. Characterization of cytochrome P450s (CYP)-overexpressing HepG2 cells for assessing drug and chemical-induced liver toxicity. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART C, TOXICOLOGY AND CARCINOGENESIS 2021; 39:68-86. [PMID: 33576714 PMCID: PMC7931144 DOI: 10.1080/26896583.2021.1880242] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Hepatic metabolism catalyzed by the cytochrome P450 (CYP) superfamily affects liver toxicity associated with exposures to natural compounds and xenobiotic agents. Previously we generated a battery of HepG2-derived stable cell lines that individually express 14 CYPs (1A1, 1A2, 1B1, 2A6, 2B6, 2C8, 2C9, 2C18, 2C19, 2D6, 2E1, 3A4, 3A5, and 3A7). In this study, we comprehensively characterized each cell line for its CYP expression and enzyme activity. Specifically, we measured the mRNA expression, protein expression, and metabolite formation. Using CYP3A4, 2D6, and 2C9-overexpressing cells as representatives, we examined the stability of these cells in long-term cultures for up to 10 passages. The results showed that CYPs can be stably overexpressed for up to 10 cell culture passages without losing their activities. The robustness of responses to stimuli among the cells at different passages was also investigated in CYP3A4-overexpressing cells and the response to amiodarone and dronedarone showed no difference between the cells at the passage 2 and 10. Moreover, the mRNA expression level of most CYPs was higher in CYP-overexpressing HepG2 cells than that in HepaRG cells and primary human hepatocytes. This study confirmed the stability of CYP-overexpressing HepG2 cell lines and provided useful information for a broader use of these cells in pharmacologic and toxicologic research.
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Affiliation(s)
- Si Chen
- Division of Biochemical Toxicology, National Center for Toxicological Research/U.S. FDA, Jefferson, Arkansas, USA
| | - Qiangen Wu
- Division of Biochemical Toxicology, National Center for Toxicological Research/U.S. FDA, Jefferson, Arkansas, USA
| | - Xilin Li
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research/U.S. FDA, Jefferson, Arkansas, USA
| | - Dongying Li
- Division of Bioinformatics and Biostatistics, National Center for Toxicological Research/U.S. FDA, Jefferson, Arkansas, USA
| | - Nan Mei
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research/U.S. FDA, Jefferson, Arkansas, USA
| | - Baitang Ning
- Division of Bioinformatics and Biostatistics, National Center for Toxicological Research/U.S. FDA, Jefferson, Arkansas, USA
| | - Montserrat Puig
- Division of Biotechnology Review and Research III, Office of Biotechnology Products, Center for Drug Evaluation and Research/U.S. FDA, Silver Spring, Maryland, USA
| | - Zhen Ren
- Division of Biochemical Toxicology, National Center for Toxicological Research/U.S. FDA, Jefferson, Arkansas, USA
| | - William H. Tolleson
- Division of Biochemical Toxicology, National Center for Toxicological Research/U.S. FDA, Jefferson, Arkansas, USA
| | - Lei Guo
- Division of Biochemical Toxicology, National Center for Toxicological Research/U.S. FDA, Jefferson, Arkansas, USA
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5
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Zhang CY, Flor S, Ludewig G, Lehmler HJ. Atropselective Partitioning of Polychlorinated Biphenyls in a HepG2 Cell Culture System: Experimental and Modeling Results. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:13817-13827. [PMID: 33059451 PMCID: PMC7642102 DOI: 10.1021/acs.est.0c02508] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Cell culture models are used to study the toxicity of polychlorinated biphenyls (PCBs); however, it is typically unknown how much PCB enters the cells and, for chiral PCBs, if the partitioning is atropselective. We investigated the partitioning of racemic PCB 91, PCB 95, PCB 132, and PCB 136 in HepG2 cells following a 72 h incubation. PCBs were present in the cell culture medium (60.7-88.8%), cells (8.0-14.6%), and dishes (2.3-7.8%) and displayed atropisomeric enrichment in the cells (enantiomeric fraction [EF] = 0.55-0.77) and dishes (EF = 0.53-0.68). Polyparameter linear free energy relationships coupled with a composition-based model provided a good estimate of the PCB levels in the cells and cell culture medium. The free concentration was subsequently used to extrapolate from the nominal cell culture concentration to PCB tissue levels and vice versa. This approach can be used for in vitro-in vivo extrapolations for all 209 PCB congeners. However, this model (and modified models based on descriptors incorporating atropselective interactions, i.e., relative retention times on chiral columns) did not predict the atropselective partitioning in the cell culture system. Improved chemical descriptors that account for the atropselective binding of PCBs to biological macromolecules are, therefore, needed to predict the atropselective partitioning of PCBs in biological systems.
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Affiliation(s)
- Chun-Yun Zhang
- Department of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Susanne Flor
- Department of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Gabriele Ludewig
- Department of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
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6
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Malina N, Mazlova EA, Kulikova O. Markers of polychlorinated biphenyl (PCB) degradation in highly contaminated soil of Central Russia. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:36587-36595. [PMID: 32564313 DOI: 10.1007/s11356-020-09712-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 06/11/2020] [Indexed: 06/11/2023]
Abstract
The highly polychlorinated biphenyl (PCB)-contaminated historical soil is located in the Serpukhov region (Central Russia). This study evaluates the processes of PCB degradation in the soil under natural conditions. Compositions of industrial mixtures (Sovol, Sovtol, and trichlorodiphenyl) were compared with PCB-contaminated soil from different depths. An increased number of dichlorobiphenyls (6 congeners) were determined in the deeper soil horizons (40-60 cm) in comparison with the surface layer (1 congener). Non-associated with industrial mixture congener, PCB 11 was determined in some soil layers with concentrations reaching 3.6 mg/kg. PCB 11 can be considered as a potential marker of activated degradation processes in highly contaminated soils with industrial mixtures. Aegopodium podagraria reduced total PCB concentrations in the contaminated soil to 25% during pot experiments. Prospective precursors of PCB 11 were significantly depleted (62-88%) after phytoremediation, but this did not increase PCB 11 concentration in the soil.
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Affiliation(s)
- Natalia Malina
- Department of Industrial Ecology, Gubkin Russian State University of Oil and Gas, Leninskiy pr-t 65k1, Moscow, Russian Federation, 119991.
| | - Elena A Mazlova
- Department of Industrial Ecology, Gubkin Russian State University of Oil and Gas, Leninskiy pr-t 65k1, Moscow, Russian Federation, 119991
| | - Olga Kulikova
- Department of Industrial Ecology, Gubkin Russian State University of Oil and Gas, Leninskiy pr-t 65k1, Moscow, Russian Federation, 119991
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7
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Uwimana E, Cagle B, Yeung C, Li X, Patterson EV, Doorn JA, Lehmler HJ. Atropselective Oxidation of 2,2',3,3',4,6'-Hexachlorobiphenyl (PCB 132) to Hydroxylated Metabolites by Human Liver Microsomes and Its Implications for PCB 132 Neurotoxicity. Toxicol Sci 2019; 171:406-420. [PMID: 31268529 PMCID: PMC6760323 DOI: 10.1093/toxsci/kfz150] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 06/18/2019] [Accepted: 06/18/2019] [Indexed: 02/05/2023] Open
Abstract
Polychlorinated biphenyls (PCBs) have been associated with neurodevelopmental disorders. Several neurotoxic congeners display axial chirality and atropselectively affect cellular targets implicated in PCB neurotoxicity. Only limited information is available regarding the atropselective metabolism of these congeners in humans and their atropselective effects on neurotoxic outcomes. Here we investigate the hypothesis that the oxidation of 2,2',3,3',4,6'-hexachlorobiphenyl (PCB 132) by human liver microsomes (HLMs) and their effects on dopaminergic cells in culture are atropselective. Racemic PCB 132 was incubated with pooled or single donor HLMs, and levels and enantiomeric fractions of PCB 132 and its metabolites were determined gas chromatographically. The major metabolite was either 2,2',3,4,4',6'-hexachlorobiphenyl-3'-ol (3'-140), a 1,2-shift product, or 2,2',3,3',4,6'-hexachlorobiphenyl-5'-ol (5'-132). The PCB 132 metabolite profiles displayed inter-individual differences and depended on the PCB 132 atropisomer. Computational studies suggested that 3'-140 is formed via a 3,4-arene oxide intermediate. The second eluting atropisomer of PCB 132, first eluting atropisomer of 3'-140, and second eluting atropisomer of 5'-132 were enriched in all HLM incubations. Enantiomeric fractions of the PCB 132 metabolites differed only slightly between the single donor HLM preparations investigated. Reactive oxygen species and levels of dopamine and its metabolites were not significantly altered after a 24 h exposure of dopaminergic cells to pure PCB 132 atropisomers. These findings suggest that there are inter-individual differences in the atropselective biotransformation of PCB 132 to its metabolites in humans; however, the resulting atropisomeric enrichment of PCB 132 is unlikely to affect neurotoxic outcomes associated with the endpoints investigated in the study.
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Affiliation(s)
- Eric Uwimana
- Interdisciplinary Graduate Program in Human Toxicology and Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, Iowa
| | - Brianna Cagle
- Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City, IA, United States
| | - Coby Yeung
- Department of Chemistry, College of Arts and Sciences, Stony Brook University, Stony Brook, New York
| | - Xueshu Li
- Interdisciplinary Graduate Program in Human Toxicology and Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, Iowa
| | - Eric V Patterson
- Department of Chemistry, College of Arts and Sciences, Stony Brook University, Stony Brook, New York
| | - Jonathan A Doorn
- Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City, IA, United States
| | - Hans-Joachim Lehmler
- Interdisciplinary Graduate Program in Human Toxicology and Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, Iowa
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Uwimana E, Ruiz P, Li X, Lehmler HJ. Human CYP2A6, CYP2B6, AND CYP2E1 Atropselectively Metabolize Polychlorinated Biphenyls to Hydroxylated Metabolites. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:2114-2123. [PMID: 30576102 PMCID: PMC6380921 DOI: 10.1021/acs.est.8b05250] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Exposure to chiral polychlorinated biphenyls (PCBs) has been associated with neurodevelopmental disorders. Their hydroxylated metabolites (OH-PCBs) are also potentially toxic to the developing human brain; however, the formation of OH-PCBs by human cytochrome P450 (P450) isoforms is poorly investigated. To address this knowledge gap, we investigated the atropselective biotransformation of 2,2',3,4',6-pentachlorobiphenyl (PCB 91), 2,2',3,5',6-pentachlorobiphenyl (PCB 95), 2,2',3,3',4,6'-hexachlorobiphenyl (PCB 132), and 2,2',3,3',6,6'-hexachlorobiphenyl (PCB 136) by different human P450 isoforms. In silico predictions with ADMET Predictor and MetaDrug software suggested a role of CYP1A2, CYP2A6, CYP2B6, CYP2E1, and CYP3A4 in the metabolism of chiral PCBs. Metabolism studies with recombinant human enzymes demonstrated that CYP2A6 and CYP2B6 oxidized PCB 91 and PCB 132 in the meta position and that CYP2A6 oxidized PCB 95 and PCB 136 in the para position. CYP2B6 played only a minor role in the metabolism of PCB 95 and PCB 136 and formed meta-hydroxylated metabolites. Traces of para-hydroxylated PCB metabolites were detected in incubations with CYP2E1. No hydroxylated metabolites were present in incubations with CYP1A2 or CYP3A4. Atropselective analysis revealed P450 isoform-dependent and congener-specific atropselective enrichment of OH-PCB metabolites. These findings suggest that CYP2A6 and CYP2B6 play an important role in the oxidation of neurotoxic PCBs to chiral OH-PCBs in humans.
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Affiliation(s)
- Eric Uwimana
- Interdisciplinary Graduate Program in Human Toxicology and Department of Occupational and Environmental Health, University of Iowa, Iowa City, IA 52242, United States
| | - Patricia Ruiz
- Division of Toxicology and Human Health Sciences, Computational Toxicology and Methods Development Lab, Agency for Toxic Substances and Disease Registry, Atlanta, GA 30333, United States
| | - Xueshu Li
- Interdisciplinary Graduate Program in Human Toxicology and Department of Occupational and Environmental Health, University of Iowa, Iowa City, IA 52242, United States
| | - Hans-Joachim Lehmler
- Interdisciplinary Graduate Program in Human Toxicology and Department of Occupational and Environmental Health, University of Iowa, Iowa City, IA 52242, United States
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