Proteomic analysis of the response of human endothelial cell line EA.hy926 to 1800 GSM mobile phone radiation

Abstract

Background: We have earlier shown that exposure of human endothelial cell line EA.hy926 to 900 MHz GSM mobile phone radiation causes changes in the expression of numerous proteins. Here, we have examined the effects of 1800 MHz GSM mobile phone signal on the proteome of the same cell line. Results: EA.hy926 cells were exposed for one hour to 1800 MHz GSM signal, simulating mobile phone talking conditions, at an average specific absorption rate (SAR) of 2.0 W/kg at 37±0.3°C. Sham samples were produced simultaneously in the same conditions but without the radiation exposure. Cells were harvested immediately after 1-hour exposure to the radiation, and proteins were extracted and separated using 2-dimensional electrophoresis (2DE). In total, 10 experimental replicates were generated from both exposed and sham samples. About 900 protein spots were detected in the 2DE-gels using PDQuest software and eight of them were found to be differentially expressed in exposed cells (p<0.05, t-test). Three out of these eight proteins were identified using Maldi-ToF mass spectrometry (MS). These proteins are: spermidine synthase (SRM), 78 kDa glucose-regulated protein (55 kDa fragment) (GRP78) and proteasome subunit alpha type 1 (PSA1). Due to the lack of the availability of commercial antibodies we were able to further examine expression of only GRP78. Using SDSPAGE and western blot method we were not able to confirm the result obtained for GRP78 using 2DE. Additionally, we have not seen any effect of 1800GSM exposure on the expression of vimentin and Hsp27 - proteins that were affected by the 900 MHz GSM exposure in our earlier studies. Conclusions: Our results suggest that the 900GSM and 1800GSM exposures might affect the expression of some proteins in the EA.hy926 cell line. The observed here discrepancy between the expression changes of GRP78 detected with 1DE and 2DE confirms the importance of validation of the results obtained with 2DE using other methods, e.g. western blot. © 2009 Nylund R, et al.