Proteomics analysis of human endothelial cells after short-term exposure to mobile phone radiation

Mobile phones have been a part of our everyday life in the developed world since the late 1990s. This has raised concerns over the potential health risks of mobile phone use. Biological and health effects potentially caused by mobile phone radiation have been extensively studied and several biological and medical endpoints have been examined. So far, results have not been conclusive on the potential effects of mobile phone radiation. Mobile phones generate a modulated radio frequency electromagnetic field (RF-EMF), which is a form of non-ionizing radiation. This means that mobile phone radiation does not have enough energy to ionize atoms and it cannot break chemical bonds directly (e.g., in DNA strands). There could, however, be other mechanisms by which mobile phone radiation may affect cellular and physiological functions. Whether these mechanisms exist is unknown. In this thesis, large-scale screening techniques, such as proteomics, were applied to examine changes on the proteome level after exposure to mobile phone radiation. Proteomics techniques allow the screening of several hundreds, and even thousands, of proteins simultaneously, and are thus more efficient than single endpoint techniques. Four different types of human endothelial cells (two cell lines, two types of primary cells) were exposed to two types of mobile phone radiation (900 and 1800 MHz GSM). The proteome of these cells was examined immediately after short-term exposure using two-dimensional gel electrophoresis (2DE). Two protein detection/analysis techniques were used: silver staining for the cell line samples and difference gel electrophoresis (DIGE) for the primary cells. 2DE-DIGE technology is currently a state-of-the-art technique in 2DE studies. Several changes were found in the proteome of the human endothelial cell line EA.hy926 after exposure to 900 MHz GSM mobile phone radiation. In addition, the proteome of a variant of the same cell line, the EA.hy926v1, was affected after 900 MHz GSM mobile phone radiation exposure, but the altered proteins were different from those in the EA.hy926 cells. The changes in the proteome of the EA.hy926 cells were weaker after 1800 MHz GSM exposure compared to those after 900 MHz GSM exposure. Furthermore, certain proteins affected earlier after 900 MHz GSM exposure were unaffected after 1800 MHz GSM exposure. The proteome of the primary human endothelial cells was not affected after 1800 MHz GSM exposure when examined using 2DE-DIGE technology. 2DE-DIGE technology is more reliable than the technology used with the EA.hy926 cell line, and these results should therefore be highly relevant when assessing the potential immediate effects of mobile phone radiation. The results presented in this thesis on the proteome-level effects of mobile phone radiation exposure are contradictory. The results with EA.hy926 cells suggest that minor effects do occur, whereas no effects were observed when using the more reliable 2DE-DIGE technology and primary cells. The responses with EA.hy926 cells varied according to the cell variant and exposure conditions, and consistent responses at the cellular level could not therefore be identified. Further research is recommended to understand the variation in responses and whether consistent cellular-level responses exist