Reduction in antioxidant defenses may contribute to ochratoxin A toxicity and carcinogenicity

Christophe Cavin, Thierry Delatour, Maricel Marin-Kuan, Daisy Holzhäuser, Larry Higgins, Claudine Bezençon, Gabriela Guignard, Sylviane Junod, Janique Richoz-Payot, Eric Gremaud, John D. Hayes, Sandra Nestler, Peter Mantle, Benoît Schilter

    Research output: Contribution to journalArticlepeer-review

    132 Citations (Scopus)


    Ochratoxin A (OTA) is a renal carcinogen in rodents. Its human health significance is unclear. It likely depends upon the mechanism of carcinogenesis. In a previous microarray study a reduction in nuclear factor-erythroid 2 p45-related factor 2 (Nrf2)-dependent gene expression was observed in the kidney but not in the liver of rats fed OTA up to 12 months. Nrf2 regulates detoxification and antioxidant gene expression. The present report shows that OTA decreased the protein expression of several markers of the Nrf2-regulated gene battery in kidney in vivo indicating that the effects observed at mRNA level may be of biological significance. The OTA-mediated Nrf2 response could be reproduced in an NRK renal cell line and in primary hepatocyte cultures. In in vitro systems, an OTA-mediated inhibition of Nrf2 activity was demonstrated by electrophoretic mobility shift and Antioxidant Regulatory Element-driven luciferase reporter assays. The reduction of Nrf2-regulated gene expression resulted in oxidative DNA damage as evidenced by formation of abasic sites in vitro and confirmed in kidney in vivo. All OTA-mediated effects observed were prevented by pretreatment of cell cultures with inducers of Nrf2 activity. Our data suggest that reduction of cellular defense against oxidative stress by Nrf2 inhibition may be a plausible mechanism of OTA nephrotoxicity and carcinogenicity.
    Original languageEnglish
    Pages (from-to)30-9
    Number of pages10
    JournalToxicological Sciences
    Issue number1
    Publication statusPublished - 2007


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