Prevention by vitamin E of DNA fragmentation and apoptosis induced by fumonisin B1 in C6 glioma cells

Fumonisin B-1 (FB1), produced by the fungus Fusarium moniliforme, belongs to a class of sphingosine analogue mycotoxins that occur widely in the food chain. Epidemiological studies have associated consumption of Fusarium moniliforme-contaminated food with human oesophageal cancer in China and South Africa. FB1 also causes equine leucoencephalomalacia. Evidence for induction of apoptosis by FB1 was first obtained when C6 glioma cells were incubated with fumonisin B-1 (3-27 mu M) causing DNA fragmentation profiles showing DNA laddering in gel electrophoresis and apoptotic bodies revealed by chromatin staining with acridine orange and ethidium bromide. Further confirmation experiments and comet assays have been performed under similar conditions. The results of the comet test show that FB1 at 9 and 18 mu M induces respectively 50 +/- 2% and 40 +/- 1% of cells with a comet with an increased tail length of 93 +/- 9 mu m and 102 +/- 17 mu m respectively. Under these concentrations, FB1 induced DNA fragmentation and laddering and many apoptotic bodies. Pre-incubation of the cells with vitamin E (25 mu M) for 24 h before FB1 (18 mu M) significantly reduced DNA fragmentation and apoptotic bodies induced by FB1.