Mobile phone base station‐emitted radiation does not induce phosphorylation of Hsp27

Abstract

An in vitro study focusing on the effects of low-level radiofrequency (RF) fields from mobile radio base stations employing the International Mobile Telecommunication 2000 (IMT-2000) cellular system was conducted to test the hypothesis that modulated RF fields act to induce phosphorylation and overexpression of heat shock protein hsp27. First, we evaluated the responses of human cells to microwave exposure at a specific absorption rate (SAR) of 80 mW/kg, which corresponds to the limit of the average whole-body SAR for general public exposure defined as a basic restriction in the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. Second, we investigated whether continuous wave (CW) and Wideband Code Division Multiple Access (W-CDMA) modulated signal RF fields at 2.1425 GHz induced activation or gene expression of hsp27 and other heat shock proteins (hsps). Human glioblastoma A172 cells were exposed to W-CDMA radiation at SARs of 80 and 800 mW/kg for 2-48 h, and CW radiation at 80 mW/kg for 24 h. Human IMR-90 fibroblasts from fetal lungs were exposed to W-CDMA at 80 and 800 mW/kg for 2 or 28 h, and CW at 80 mW/kg for 28 h. Under the RF field exposure conditions described above, no significant differences in the expression levels of phosphorylated hsp27 at serine 82 (hsp27[pS82]) were observed between the test groups exposed to W-CDMA or CW signal and the sham-exposed negative controls, as evaluated immediately after the exposure periods by bead-based multiplex assays. Moreover, no noticeable differences in the gene expression of hsps were observed between the test groups and the negative controls by DNA Chip analysis. Our results confirm that exposure to low-level RF field up to 800 mW/kg does not induce phosphorylation of hsp27 or expression of hsp gene family.

Mobile phone base station radiation does not affect neoplastic transformation in BALB/3T3 cells

“…We also confirmed that exposure to low level RF fields of up to 800 mW/kg did not induce p53 phosphorylation, p53-dependent apoptosis, or other stress responses in A172 and IMR-90 cells . Furthermore, phosphorylation and gene expression of hsp27 in A172 and IMR-90 cells were not affected by exposure to low level RF fields [Hirose et al, 2007]. In the present study, exposure to low level RF fields at 80 and 800 mW/kg did not induce cell transformation.…”

Review of possible modulation‐dependent biological effects of radiofrequency fields

“…A number of studies have addressed effects of RF energy on heat shock proteins. Capri et al [2004a] investigated hsp70 levels in human peripheral blood mononuclear cells (Table 3); Hirose et al [2007] studied phosphorylation of hsp27 and heat shock gene expression in human A172 glioblastoma cells and IMR-90 fibroblasts; Lantow et al [2006a,b] measured hsp70 expression in human umbilical cord blood-derived monocytes and lymphocytes, human Mono Mac 6 and K562 cells (Table 3); Laszlo et al [2005] used human HeLa S3 cells, hamster ovary HA-1 fibroblasts and C3H/10T½ cells to study the DNA-binding activity of heat shock factor; Lim et al [2005] measured the number of cells expressing hsp70 or hsp27 in human leukocytes and Simko et al [2006] studied hsp70 in human Mono Mac 6 cells after combined exposure to RF fields and ultrafine particles. No effects of RF fields were found in any of these studies.…”

Cellular Biology Aspects of Mobile Phone Radiation

“…Moreover, no noticeable differences in the gene expression of HSPs were observed between the test groups and the negative controls by DNA Chip analysis (Hirose et al, 2007) .…”