title: Effects of the exposure to intermittent 1.8 GHz radio frequency electromagnetic fields on HSP70 expression and MAPK signaling pathways in PC12 cells.
abstract: OBJECTIVE
  We previously reported effects on heat shock protein 70 (HSP70) mRNA expression, a cytoprotective protein induced under stressful condition, in human trophoblast cells exposed to amplitude-modulated Global System for Mobile Communication (GSM) signals. In the present work the same experimental conditions were applied to the rat PC12 cells, in order to assess the stress responses mediated by HSP70 and by the Mitogen Activated Protein Kinases (MAPK) in neuronal-like cells, an interesting model to study possible effects of mobile phone frequencies exposure.
  
  
  METHODS
  HSP70 gene expression level was evaluated by reverse transcriptase polymerase chain reaction, HSP70 protein expression and MAPK phosphorylation were assessed by Western blotting. PC12 cells were exposed for 4, 16 or 24 h to 1.8 GHz continuous wave signal (CW, carrier frequency without modulation) or to two different GSM modulation schemes, GSM-217Hz and GSM-Talk (which generates temporal changes between two different GSM signals, active during talking or listening phases, respectively, thus simulating a typical conversation). Specific adsorption rate (SAR) was 2 W/kg.
  
  
  RESULTS
  After PC12 cells exposure to the GSM-217Hz signal for 16 or 24 h, HSP70 transcription significantly increased, whereas no effect was observed in cells exposed to the CW or GSM-Talk signals. HSP70 protein expression and three different MAPK signaling pathways were not affected by the exposure to any of the three different 1.8 GHz signals.
  
  
  CONCLUSIONS
  The positive effect on HSP70 mRNA expression, observed only in cells exposed to the GSM-217Hz signal, is a repeatable response previously reported in human trophoblast cells and now confirmed in PC12 cells. Further investigations towards a possible role of 1.8 GHz signal modulation are therefore advisable.
authors: Interdepartmental Centre for Environmental Science Research, University of Bologna , Ravenna.
authors: Paola
authors: P
authors: Valbonesi
authors: Silvia
authors: S
authors: Franzellitti
authors: Ferdinando
authors: F
authors: Bersani
authors: Andrea
authors: A
authors: Contin
authors: Elena
authors: E
authors: Fabbri
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000528:radiation effects; D004574:Electromagnetic Fields / Q000009:adverse effects*; D005786:Gene Expression Regulation / Q000528:radiation effects*; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics*; D020935:MAP Kinase Signaling System / Q000528:radiation effects*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D016716:PC12 Cells; D010766:Phosphorylation / Q000528:radiation effects; D011846:Radio Waves / Q000009:adverse effects*; D051381:Rats
chemical_list: D018840:HSP70 Heat-Shock Proteins; D020928:Mitogen-Activated Protein Kinases