Abstract
For studies on the aryl hydrocarbon receptor (AhR)-dependent toxicity of the mycotoxins alternariol (AOH) and alternariol methyl ether (AME), three mouse hepatoma (Hepa-1) cell lines with intact and with compromised AhR signaling were compared with respect to their activities for hydroxylation, methylation, and glucuronidation. Whereas the activities of cytochrome P450-mediated monooxygenase and catechol-O-methyl transferase were very low and did not differ between the three cell lines, a pronounced difference was observed for UDP-glucuronosyl transferase activity, which was much higher in Hepa-1c1c4 than in c1c7 and c1c12 cells. In all three cell types, the rate of glucuronidation of AOH was about four times higher than that of AME. Whereas AME caused a concentration-dependent G2/M arrest in each cell line, AOH arrested Hepa-1c1c7 and c1c12 cells but not c1c4 cells. However, Hepa-1c1c4 cells were arrested by AOH when β-glucuronidase was added to the incubation medium in order to reverse the formation of AOH glucuronides. We conclude that the failure of AOH to cause cell cycle inhibition in Hepa-1c1c4 cells is due to its efficient glucuronidation. The considerable UDP-glucuronosyl transferase activity of Hepa-1c1c4 cells should be taken into account when other compounds are studied in this cell line. Moreover, we demonstrate that differences in glucuronide formation between cell types can be overcome by the addition of β-glucuronidase to the cell culture medium.
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Abbreviations
- AhR:
-
Arylhydrocarbon receptor
- AME:
-
Alternariol-9-O-methyl ether
- AOH:
-
Alternariol
- ARNT:
-
Arylhydrocarbon receptor nuclear translocator
- COMT:
-
Catechol-O-methyl transferase
- CYP:
-
Cytochrome P450
- DMEM:
-
Dulbecco’s modified Eagle medium
- DMSO:
-
Dimethylsulfoxide
- FCS:
-
Fetal calf serum
- LC–MS:
-
Liquid chromatography-mass spectrometry
- PBS:
-
Phosphate-buffered saline
- SAM:
-
S-adenosyl-l-methionine
- TFMU:
-
Trifluoromethylumbelliferone
- UDP:
-
Uridinediphospho
- UDPGA:
-
UDP-glucuronic acid
- UGT:
-
UDP-glucuronosyl transferase
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Acknowledgments
This study was supported by KIT (Research Program “Mycotoxins” as part of the Research Initiative “Food and Health”).
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The authors declare that there are no conflicts of interest.
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Burkhardt, B., Jung, S.A., Pfeiffer, E. et al. Mouse hepatoma cell lines differing in aryl hydrocarbon receptor-mediated signaling have different activities for glucuronidation. Arch Toxicol 86, 643–649 (2012). https://doi.org/10.1007/s00204-011-0789-8
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DOI: https://doi.org/10.1007/s00204-011-0789-8