Evaluation of HSP70 expression and DNA damage in a human trophoblast cell line exposed to 1.8 GHz amplitude-modulated radiofrequency fields

The aim of this study was to determine whether high-frequency electromagnetic fields (HF-EMF) could induce cellular effects. The human trophoblast cell line HTR-8/SVneo was used as a model to evaluate the expression of proteins (HSP70 and HSC70) and genes (HSP70A, B, C and HSC70) of the HSP70 family and the primary DNA damage response after non-thermal exposure to pulse- modulated 1817 MHz sinusoidal waves (GSM-217 Hz; 1 h; SAR of 2 W/Kg). HSP70 expression was significantly enhanced by heat, applied as the prototypical stimulus. The HSP70A, B and C transcripts were differentially expressed under basal conditions however they were all significantly induced above basal by thermal stress. Conversely, HSC70 protein and gene expression was not influenced by heat. Exposing HTR-8/SVneo cells to HF-EMF did not result in changes in either HSP70 or HSC70 protein and gene expression. A significant increase in DNA strand breaks was caused by exposure to H2O2, used as a positive stimulus; however no effect was observed after cell exposure to HF-EMF. Overall, no evidence was found that a 1-h exposure to GSM-217 Hz induced a HSP70-mediated stress response or primary DNA damage in HTR-8/SVneo cells. Nevertheless, further investigations on trophoblast cell responses after exposure to GSM signals of different type and duration are needed