Effects of radiofrequency radiation on apoptotic and antiapoptotic factors in colorectal cancer cells.

ABSTRACT

In this study, it is aimed to investigate the effect of radiofrequency radiation (RFR) on apoptotic and antiapoptotic factors under different exposure conditions in human colonic adenocarcinoma cells (Caco-2). We analyzed the effects of 2.5 GHz continuous wave and 3 GPP modulated radiofrequency radiation exposure (15 min on, 15 min off) for 1 h and (1 h on, 1 h off) for 3 hours on Caco-2 cell lines. The cell viability of Caco-2 cells was determined by XTT method. Then, the cells were analyzed by flow cytometry to determine the effects on apoptosis staining with AnnexinV-FITC and PI. Protein expression levels of Bcl-2, Bax, Caspase-3 and Survivin were subsequently analyzed by using flow cytometric methods. Bax, Caspase 8, and Survivin protein levels were also analyzed by western blot. The cell viability rates were not significantly different after 2.5 GHz of RFR exposure for 1 h, but RFR exposure for 3 h at 2.5 GHz frequencies caused a decrease on cell viability of Caco-2 cells. RFR exposure for 1 and 3 hours at 2.5 GHz frequencies resulted in an apoptotic response. Protein analyses of Bcl-2, Bax, Survivin, Caspase-3, and Caspase-8 showed that RFR led to increase the levels of proapoptotic Bax, Caspase-3, and Caspase 8 in Caco-2 cells under different exposure conditions. However, 3-h exposure caused a decrease in antiapoptotic survivin levels. The results of our study indicate that RFR exposure affects the cell death mechanism due to apoptotic pathway.