Ding GR, Wang XW, Li KC, Qiu LB, Xu SL, Tan J, Guo GZ. (2009) Comparison of Hsps expression after radio-frequency field exposure in three human glioma cell lines. Biomed Environ Sci. 22(5):374-80.
Hyperthermia and exposure to a wide variety of toxins result in synthesis of heart shock protein (HSP). It has been shown that exposure to electromagnetic fields induces heat shock response in human HL-60 cells and human endothelial cells. It was reported that exposure to 1950 MHz radiofrequency field (RF) did not change the expression level of Hsp27 or Hsp70 in MO54 glioma cells, but slightly inhibited the phosphorylation of Hsp27 in these cells.
The objective of this study was to investigate and compare the effect of RF exposure on expression of stress response genes (Hsps) in three human glioma cell lines (MO54, A172, and T98).
The cells were exposed to 1950 MHz continuous-wave RF field at specific absorption rate (SAR=1 W/kg) and at SAR=10 W/kg, or sham-exposed for 1 hour. Localization and expression of Hsp27 and phosphorylated Hsp-27 (p-Hsp-27) were detected by immunofluorescent staining; the levels of expression of Hsp27, p-Hs27, and Hsp70 were determined by Western blotting.
In the absence of exposure, Hsp27 was located mainly in the cytoplasm of MO54, A172, and T98 cells. RF exposure (10 W/kg, 1 h) did not affect the distribution or expression of Hsp27 in any cell line. In the absence of exposure, p-Hsp27 was located both in the cytoplasm and in the nuclei of MO54, A172, and T98 cells. After RF exposure (10 W/kg, 1 h), the p-Hsp27 immunofluorescence became slightly weaker in MO54 cells compared to control cells. Western blotting did not show any difference in Hsp27 and Hsp70 expression level between A172, MO54, and T98 cells exposed to RF fields (1 W/kg or 10 W/kg) and sham-exposed cells. Expression level of p-Hsp27 in MO54 cells was slightly decreased after exposure to RF at SAR 10 W/kg, but not after exposure at SAR=1 W/kg.
Interpretation and Conclusion
The results of this study show that 1950 MHz RF exposure for 1 hour at SAR level of 1 or 10 W/kg has little or no effect on Hsp70 and Hsp27 expression in MO54, A172, and T98 human glioma cell lines.