Induction of MAPK-dependent transcription factors by deoxynivalenol in human cell lines

Contamination of cereals with the trichothecene deoxynivalenol (DON) is a global problem in agriculture. DON-related cytotoxicity results from inhibition of translation preceded by a ribotoxic stress response, which is characterized by phosphorylation of the mitogen-activated protein kinases and activation of downstream transcription factors. In this study, we measured the expression of AP-1 associated transcription factor mRNA levels in six human cell lines (Hep-G2, A549, U937, A204, Jurkat, and CaCo-2) by using real-time RT-PCR. Previous work suggested that transcription factors mRNA and protein levels are affected by DON in Hep-G2 cells. In this study, we found significant cell-specific differences in mRNA levels for the transcription factors JUN, JUND, FOS, FOSL2, ATF3, and EGR1. After exposure to 1 µmol/l DON for 3 h, the induction of the transcription factor JUN was highest in the Jurkat (342-fold) and Hep-G2 (84-fold) cell lines. JUND expression was mainly affected in the immunocompetent cell-lines U937 (11-fold) and Jurkat (12-fold), whereas significant FOSL2 induction (5-fold) was only found in Jurkat cells. DON-induced expression of FOS was mainly observed in Hep-G2 (96-fold) and U937 cells (59-fold). In contrast, response of A549 cells to DON was characterized by a distinct induction of ATF3 (44-fold) and EGR1 (92-fold). Time- and concentration-dependent induction of the transcription factors by DON was studied in detail for Hep-G2, A549, A204, and U937 cells. Considering the chronic dietary exposure of humans, broader investigations on DON influence on cell signaling pathways are required to understand the impact of this mycotoxin on human health.