Isabella Randerath, Thomas Schettgen, Julian Peter Müller, Jens Rengelshausen, Susanne Ziegler, Nathalia Quinete, Jens Bertram, Salah Laieb, Elke Schaeffeler, Andrea Kaifie, Katja S. Just, Aaron Voigt, Roman Tremmel, Matthias Schwab, Julia C. Stingl, Thomas Kraus, Patrick Ziegler
{"title":"Metabolic activation of WHO-congeners PCB28, 52, and 101 by human CYP2A6: evidence from in vitro and in vivo experiments","authors":"Isabella Randerath, Thomas Schettgen, Julian Peter Müller, Jens Rengelshausen, Susanne Ziegler, Nathalia Quinete, Jens Bertram, Salah Laieb, Elke Schaeffeler, Andrea Kaifie, Katja S. Just, Aaron Voigt, Roman Tremmel, Matthias Schwab, Julia C. Stingl, Thomas Kraus, Patrick Ziegler","doi":"10.1007/s00204-024-03836-w","DOIUrl":null,"url":null,"abstract":"<div><p>Despite extensive research on the metabolism of polychlorinated biphenyls (PCBs), knowledge gaps persist regarding their isoform-specific biotransformation pathways. This study aimed to elucidate the role of different cytochrome P450 enzymes in PCB metabolism, focusing on WHO-congeners 2,4,4′-trichlorobiphenyl (PCB28), 2,2′,5,5′-tetrachlorobiphenyl (PCB52), and 2,2′,4,5,5′-pentachlorobiphenyl (PCB101). Utilizing engineered HEK293 cell lines, we investigated the in vitro metabolism of these PCBs by CYP1A2, CYP2C8, CYP2C9, CYP3A4, CYP2A6, and CYP2E1, revealing robust production of hydroxylated metabolites. Our results show that CYP2A6 plays a major role in the metabolism of these congeners responsible for predominant formation of para-position hydroxylated metabolites, with concentrations reaching up to 1.61 µg/L (5,89 nM) for PCB28, 316.98 µg/L (1,03 µM) for PCB52, and 151.1 µg/L (441 nM) for PCB101 from a 20 µM parent PCB concentration. Moreover, concentration-dependent cytotoxic and cytostatic effects induced by reactive intermediates of the PCB hydroxylation pathway were observed in HEK293CYP2A6 cells, for all three congeners tested. CYP2A6 was specifically capable of activating PCBs 28 and 101 to genotoxic metabolites which produced genetic defects which were propagated to subsequent generations, potentially contributing to carcinogenesis. In a clinical study examining CYP2A6 enzyme activity in formerly exposed individuals with elevated internal PCB levels, a participant with increased enzyme activity showed a direct association between the phenotypic activity of CYP2A6 and the metabolism of PCB28, confirming the role of CYP2A6 in the in vivo metabolism of PCB28 also in humans. These results altogether reinforce the concept that CYP2A6 plays a pivotal role in PCB congener metabolism and suggest its significance in human health, particularly in the metabolism of lower chlorinated, volatile PCB congeners.</p></div>","PeriodicalId":8329,"journal":{"name":"Archives of Toxicology","volume":null,"pages":null},"PeriodicalIF":4.8000,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00204-024-03836-w.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Archives of Toxicology","FirstCategoryId":"3","ListUrlMain":"https://link.springer.com/article/10.1007/s00204-024-03836-w","RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"TOXICOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Despite extensive research on the metabolism of polychlorinated biphenyls (PCBs), knowledge gaps persist regarding their isoform-specific biotransformation pathways. This study aimed to elucidate the role of different cytochrome P450 enzymes in PCB metabolism, focusing on WHO-congeners 2,4,4′-trichlorobiphenyl (PCB28), 2,2′,5,5′-tetrachlorobiphenyl (PCB52), and 2,2′,4,5,5′-pentachlorobiphenyl (PCB101). Utilizing engineered HEK293 cell lines, we investigated the in vitro metabolism of these PCBs by CYP1A2, CYP2C8, CYP2C9, CYP3A4, CYP2A6, and CYP2E1, revealing robust production of hydroxylated metabolites. Our results show that CYP2A6 plays a major role in the metabolism of these congeners responsible for predominant formation of para-position hydroxylated metabolites, with concentrations reaching up to 1.61 µg/L (5,89 nM) for PCB28, 316.98 µg/L (1,03 µM) for PCB52, and 151.1 µg/L (441 nM) for PCB101 from a 20 µM parent PCB concentration. Moreover, concentration-dependent cytotoxic and cytostatic effects induced by reactive intermediates of the PCB hydroxylation pathway were observed in HEK293CYP2A6 cells, for all three congeners tested. CYP2A6 was specifically capable of activating PCBs 28 and 101 to genotoxic metabolites which produced genetic defects which were propagated to subsequent generations, potentially contributing to carcinogenesis. In a clinical study examining CYP2A6 enzyme activity in formerly exposed individuals with elevated internal PCB levels, a participant with increased enzyme activity showed a direct association between the phenotypic activity of CYP2A6 and the metabolism of PCB28, confirming the role of CYP2A6 in the in vivo metabolism of PCB28 also in humans. These results altogether reinforce the concept that CYP2A6 plays a pivotal role in PCB congener metabolism and suggest its significance in human health, particularly in the metabolism of lower chlorinated, volatile PCB congeners.
期刊介绍:
Archives of Toxicology provides up-to-date information on the latest advances in toxicology. The journal places particular emphasis on studies relating to defined effects of chemicals and mechanisms of toxicity, including toxic activities at the molecular level, in humans and experimental animals. Coverage includes new insights into analysis and toxicokinetics and into forensic toxicology. Review articles of general interest to toxicologists are an additional important feature of the journal.