To study whether exposure to 50 Hz electromagnetic fields raised anti-apoptotic BAG3 protein levels (as marker for stress) in the human melanoma cell lines in vitro and in xenografts (i.e. M14 cells were subcutaneously injected on the back of 30 BALB/c nu/nu mice (15 mice were exposed)).
Exposure of cultured cells or xenografts for 6 hours or 4 weeks, respectively, produced a significant increase in BAG3 protein expression. Interestingly, at the same times, the authors could not detect any significant variation in the levels of HSP70/HSP72 protein or cell apoptosis.
These data confirm the stressful effect of exposure to extremely low frequency in human cells, by identifying BAG3 protein as a marker of extremely low frequency-induced stress. Furthermore, the findings suggest that BAG3 induction by extremely low frequency may contribute to melanoma cell survival and/or resistance to therapy.