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

Fumonisin B₁ (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 B₁ (3-27 μM) 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 μM induces respectively 50 ± 2% and 40 ± 1% of cells with a comet with an increased tail length of 93 ± 9 μm and 102 ± 17 μm respectively. Under these concentrations, FB₁ induced DNA fragmentation and laddering and many apoptotic bodies. Pre-incubation of the cells with vitamin E (25 μM) for 24 h before FB₁ (18 μM) significantly reduced DNA fragmentation and apoptotic bodies induced by FB₁.