Non-thermal activation of the hsp27/p38MAPK stress pathway by mobile phone radiation in human endothelial cells: molecular mechanism for cancer- and blood-brain barrier-related effects

Differentiation. 2002 May;70(2-3):120-9. doi: 10.1046/j.1432-0436.2002.700207.x.

Abstract

We have examined whether non-thermal exposures of cultures of the human endothelial cell line EA.hy926 to 900 MHz GSM mobile phone microwave radiation could activate stress response. Results obtained demonstrate that 1-hour non-thermal exposure of EA.hy926 cells changes the phosphorylation status of numerous, yet largely unidentified, proteins. One of the affected proteins was identified as heat shock protein-27 (hsp27). Mobile phone exposure caused a transient increase in phosphorylation of hsp27, an effect which was prevented by SB203580, a specific inhibitor of p38 mitogen-activated protein kinase (p38MAPK). Also, mobile phone exposure caused transient changes in the protein expression levels of hsp27 and p38MAPK. All these changes were non-thermal effects because, as determined using temperature probes, irradiation did not alter the temperature of cell cultures, which remained throughout the irradiation period at 37 +/- 0.3 degrees C. Changes in the overall pattern of protein phosphorylation suggest that mobile phone radiation activates a variety of cellular signal transduction pathways, among them the hsp27/p38MAPK stress response pathway. Based on the known functions of hsp27, we put forward the hypothesis that mobile phone radiation-induced activation of hsp27 may (i) facilitate the development of brain cancer by inhibiting the cytochrome c/caspase-3 apoptotic pathway and (ii) cause an increase in blood-brain barrier permeability through stabilization of endothelial cell stress fibers. We postulate that these events, when occurring repeatedly over a long period of time, might become a health hazard because of the possible accumulation of brain tissue damage. Furthermore, our hypothesis suggests that other brain damaging factors may co-participate in mobile phone radiation-induced effects.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Cell Phone*
  • Endothelium / cytology
  • Endothelium / radiation effects*
  • Enzyme Activation
  • HSP27 Heat-Shock Proteins
  • Heat-Shock Proteins*
  • Humans
  • Immunohistochemistry
  • MAP Kinase Signaling System / physiology*
  • Microwaves / adverse effects*
  • Mitogen-Activated Protein Kinases / physiology
  • Mitogen-Activated Protein Kinases / radiation effects*
  • Models, Biological
  • Neoplasm Proteins / metabolism*
  • Phosphorylation
  • Time Factors
  • p38 Mitogen-Activated Protein Kinases

Substances

  • HSP27 Heat-Shock Proteins
  • HSPB1 protein, human
  • Heat-Shock Proteins
  • Neoplasm Proteins
  • Mitogen-Activated Protein Kinases
  • p38 Mitogen-Activated Protein Kinases