2-GHz Band CW and W-CDMA Modulated Radiofrequency Fields Have No Significant Effect on Cell Proliferation and Gene Expression Profile in Human Cells

Abstract

We investigated the mechanisms by which radiofrequency (RF) fields exert their activity, and the changes in both cell proliferation and the gene expression profile in the human cell lines, A172 (glioblastoma), H4 (neuroglioma), and IMR-90 (fibroblasts from normal fetal lung) following exposure to 2.1425 GHz continuous wave (CW) and Wideband Code Division Multiple Access (W-CDMA) RF fields at three field levels. During the incubation phase, cells were exposed at the specific absorption rates (SARs) of 80, 250, or 800 mW/kg with both CW and W-CDMA RF fields for up to 96 h. Heat shock treatment was used as the positive control. No significant differences in cell growth or viability were observed between any test group exposed to W-CDMA or CW radiation and the sham-exposed negative controls. Using the Affymetrix Human Genome Array, only a very small (< 1%) number of available genes (ca. 16,000 to 19,000) exhibited altered expression in each experiment. The results confirm that low-level exposure to 2.1425 GHz CW and W-CDMA RF fields for up to 96 h did not act as an acute cytotoxicant in either cell proliferation or the gene expression profile. These results suggest that RF exposure up to the limit of whole-body average SAR levels as specified in the ICNIRP guidelines is unlikely to elicit a general stress response in the tested cell lines under these conditions.

Cytostatic response of NB69 cells to weak pulse-modulated 2.2 GHz radar-like signals

“…However, the available evidence on RF effects on cell proliferation is scarce and the results are conflicting. Some studies have failed to find significant modifications in cell growth, cell survival and/ or cell cycle distribution on various in vitro systems [Higashikubo et al, 2001;Merola et al, 2006;Sekijima et al, 2010]. In contrast, other studies have reported altered cell proliferation after exposure to RF at doses above those applied in the present study [Cleary et al, 1996;Velizarov et al, 1999;Takashima et al, 2006].…”

“…These results have received limited support from experimental data showing that RF fields can induce DNA breaks [Lai and Singh, 1996;Phillips et al, 1998;Schwarz et al, 2008;Garaj-Vrhovac and Orescanin, 2009], and chromosome aberration or activation of oncogene transcription [Ivaschuk et al, 1997;Goswami et al, 1999;Mazor et al, 2008]. Although these in vivo and in vitro results could be indicative of potential detrimental effects due to exposure to weak RF fields, other experimental results do not support this hypothesis [Speit et al, 2007;Sekijima et al, 2010]. Thus, the possibility that the reported biological responses are induced through phenomena that do not involve significant hyperthermia remains a controversial issue that needs to be elucidated.…”

“…The results of in vitro and in vivo studies are also rather conflicting in terms of the mechanistic explanation of the cellular events observed. So, a number of experimental studies on different biological models have failed to detect significant responses to RF radiation at subthermal doses [Higashikubo et al, 2001;Utteridge et al, 2002;Merola et al, 2006;Tillmann et al, 2007;Sekijima et al, 2010].…”

Does MW Radiation Affect Gene Expression, Apoptotic Level, and Cell Cycle Progression of Human SH-SY5Y Neuroblastoma Cells?

“…Real-time RT-PCR and flow cytometry analyses revealed no effect in transcript levels of the cellular stress protein levels, apoptosis, and cell cycle of cells that were exposed to GSM-like at a SAR level of 0.2 W/kg [10]. Sekijima et al [7] checked the expression levels after 96 h of 2.1425 CW and W-CDMA MW radiation (80, 250, and 800 mW/kg) in A172 human glioblas-toma cell line. However, they did not observe any significant difference in gene expression levels between MW-exposed and control cells.…”

“…Contradictory results have been reported in the literature which had investigated the possible adverse health effects of MW radiation. Although some researchers reported significant changes in cell progression, proliferation, and gene expression due to MW radiation exposure, others failed to found any significant change [1][2][3][4][5][6][7][8][9][10][11][12][13]. Remondini et al [3] reported that Bcl-2-associated transcription factor (BTF) gene was down-regulated in EAhy926 human endothelial cells due to exposure of cells to 900 MHz GSM modulated MW radiation at specific absorption rate (SAR) levels of 1.8 and 2.5 W/kg for 1 h. The effects of 835.62 and 847.74 MHz continuous wave MW radiation on cell cycle progression were investigated in mouse fibroblast C3H 10T(1/2) and human glioma U87MG cells by Higashikubo et al [12].…”