Radiofrequency radiation (900 MHz) induces Egr‐1 gene expression and affects cell‐cycle control in human neuroblastoma cells

Abstract

Many environmental signals, including ionizing radiation and UV rays, induce activation of Egr-1 gene, thus affecting cell growth and apoptosis. The paucity and the controversial knowledge about the effect of electromagnetic fields (EMF) exposure of nerve cells prompted us to investigate the bioeffects of radiofrequency (RF) radiation on SH-SY5Y neuroblastoma cells. The effect of a modulated RF field of 900 MHz, generated by a wire patch cell (WPC) antenna exposure system on Egr-1 gene expression, was studied as a function of time. Short-term exposures induced a transient increase in Egr-1 mRNA level paralleled with activation of the MAPK subtypes ERK1/2 and SAPK/JNK. The effects of RF radiations on cell growth rate and apoptosis were also studied. Exposure to RF radiation had an antiproliferative activity in SH-SY5Y cells with a significant effect observed at 24 h. RF radiation impaired cell cycle progression, reaching a significant G 2 -M arrest. In addition, the appearance of the sub-G 1 peak, a hallmark of apoptosis, was highlighted after a 24-h exposure, together with a significant decrease in mRNA levels of Bcl-2 and survivin genes, both interfering with signaling between G 2 -M arrest and apoptosis. Our results provide evidence that exposure to a 900 MHz-modulated RF radiation affect both Egr-1 gene expression and cell regulatory functions, involving apoptosis inhibitors like Bcl-2 and survivin, thus providing important insights into a potentially broad mechanism for controlling in vitro cell viability.

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

“…Besides, though subtle and with no relevant impact on the overall population, statistically significant, mutually compensatory changes in the fraction of necrotic/apoptotic cells were detected in NB69 after RF exposure. This suggests that RF fields can exert an effect on mechanisms intervening on survival of neuroblastoma cells, as proposed by Buttiglione et al [2007]. As a whole, these results are not supportive of the hypothesis that RF signals at low doses can exert carcinogenic effects by increasing cell proliferation.…”

“…Conversely, other studies have reported changes in DNA synthesis, cell cycle control and/or apoptosis [Marinelli et al, 2004;Caraglia et al, 2005], protein and gene expression [Czyz et al, 2004;Buttiglione et al, 2007;Karinen et al, 2008] or tumorigenesis [Repacholi et al, 1997] in different systems exposed to weak RF signals. Additionally, a number of studies have documented the ability of RF radiation to affect biochemical and molecular mechanisms, inducing effects that are potentially independent of thermal phenomena [Litovitz et al, 1993;Cleary et al, 1996;Leszczynski et al, 2002;Remondini et al, 2006;Rao et al, 2008].…”

Effects of Early-Onset Radiofrequency Electromagnetic Field Exposure (GSM 900 MHz) on Behavior and Memory in Rats

“…Few studies of RF EMF effects on cell differentiation have been completed, in contrast to studies using cultured neurons (Buttiglione et al, 2007;Del Vecchio et al, 2009;Joubert et al, 2007Joubert et al, & 2008. Several studies of neuronal differentiation following RF EMF exposure are ongoing in Italy and Germany.…”

Beneficial Effects of Electromagnetic Radiation in Cancer

“…High resolution 1 H-NMR spectroscopy also revealed an apoptosis like behavior, when K562 (human muelogenous leukaemia) cells were exposed to ELF 50 Hz sinusoidal magnetic field of 1mT or 5mT, for 2h (Santini et al, 2005). Moreover, continuous exposure of SH-SY5Y (human neuroblastoma) cells to a 900MHz radiofrequency radiation (SAR: 1W/kg), for 24h, leads to significant reduction in the viability of neuroblastoma cells (Buttiglione et al, 2007), whereas exposure of human epidermoid cancer KB cells at a 1.95MHz non-thermal electromagnetic field (SAR 3.6±0.2 mW/g) induced a time-dependent apoptosis, which reached 45% after 3h of exposure (Caraglia et al, 2005).…”