title: Effects of a 2450 MHz high-frequency electromagnetic field with a wide range of SARs on the induction of heat-shock proteins in A172 cells.
abstract: In this study, we investigated whether exposure to 2450 MHz high-frequency electromagnetic fields (HFEMFs) could act as an environmental insult to evoke a stress response in A172 cells, using HSP70 and HSP27 as stress markers. The cells were exposed to a 2450 MHz HFEMF with a wide range of specific absorption rates (SARs: 5-200 W/kg) or sham conditions. Because exposure to 2450 MHz HFEMF at 50-200 W/kg SAR causes temperature increases in culture medium, appropriate heat control groups (38-44 degrees C) were also included. The expression of HSP 70 and HSP 27, as well as the level of phosphorylated HSP 27 ((78)Ser) (p-HSP27), was determined by Western blotting. Our results showed that the expression of HSP 70 increased in a time and dose-dependent manner at >50 W/kg SAR for 1-3 h. A similar effect was also observed in corresponding heat controls. There was no significant change in HSP 27 expression caused by HFEMF at 5-200 W/kg or by comparable heating for 1-3 h. However, HSP 27 phosphorylation increased transiently at 100 and 200 W/kg to a greater extent than at 40-44 degrees C. Phosphorylation of HSP 27 reached a maximum after 1 h exposure at 100 W/kg HFEMF. Our results suggest that exposure to a 2450 MHz HFEMF has little or no apparent effect on HSP70 and HSP27 expression, but it may induce a transient increase in HSP27 Phosphorylation in A172 cells at very high SAR (>100 W/kg).
authors.affiliation: Department of Radiological Technology, School of Health Sciences, Faculty of Medicine, Hirosaki University, Hirosaki, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.forename: S
authors.initials: S
authors.lastname: Koyama
authors.forename: Y
authors.initials: Y
authors.lastname: Komatsubara
authors.forename: Y
authors.initials: Y
authors.lastname: Suzuki
authors.forename: M
authors.initials: M
authors.lastname: Taki
authors.forename: J
authors.initials: J
authors.lastname: Miyakoshi
mesh_terms: D045744:Cell Line, Tumor; D002470:Cell Survival / Q000528:radiation effects; D004574:Electromagnetic Fields / Q000009:adverse effects*; D005909:Glioblastoma / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000096:biosynthesis*; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans
chemical_list: D006360:Heat-Shock Proteins