Medical/biological Study (experimental study)

High frequency electromagnetic fields (GSM signals) affect gene expression levels in tumor suppressor p53-deficient embryonic stem cells. med./biol.

PubMed Entry

Journal web site

Aim of study (according to author)
The effects of electromagnetic field exposure were comparatively analyzed in pluripotent embryonic stem cells and embryonic carcinoma cells, including embryonic stem cells deficient for p53, a tumor suppressor protein, to determine the cellular susceptibility to develop spontaneous tumors.
Background/further details:
Two GSM modulation schemes (GSM-217 and GSM-Talk), which generate temporal changes between GSM-Basic (active during talking phases) and GSM-DTX (active during listening phases thus simulating a typical conversation), were applied to the cells.

Endpoints

• molecular biosynthesis: gene expression
• cell viability/cell division/proliferation: cell differentiation, cell cycle phase, and proliferation

Exposure
General category: mobile communication system, GSM

Field characteristics	Parameters
field 1: 1.71 GHz pulsed (PW) exposure duration: intermittent, 5/30 min On/Off cycles for 6 or 48 hours	SAR: 1.5 W/kg average over time SAR: 12 W/kg (slot SAR)
field 2: 1.71 GHz pulsed (PW) exposure duration: intermittent, 5/30 min On/Off cycles for 72 hours	SAR: 2 W/kg average over time SAR: 16 W/kg (slot SAR)
field 3: 1.71 GHz pulsed (PW) exposure duration: intermittent, 5/30 min On/Off cycles for 22 or 40 hours	SAR: 2 W/kg average over time SAR: 16 W/kg (slot SAR)
field 4: 1.71 GHz pulsed (PW) exposure duration: intermittent, 5/30 min On/Off cycles for 6 or 48 hours	SAR: 0.4 W/kg average over time SAR: 8 W/kg (slot SAR)

Exposed system:
intact cell/cell culture (in vitro)
pluripotent R1 embryonic stem cells, wild-type D3 and p53-deficient; embryonic carcinoma cells of line P19

Methods
Endpoint/Measurement parameters/Methodology

• molecular biosynthesis: expression of early response and growth regulatory genes (c-fos, c-jun, c-myc, early growth response-1(egr-1), hsp70, p21, p53, bcl-2, alpha-myosin heavy chain (alpha-MHC as degree of cardiac differentiation), beta-tubulin) (RT-PCR)
• cell viability/cell division/proliferation: cell differentiation (cardiac differentiation/number of embryoid body outgrowth containing spontaneously beating cardiomyocytes); cell cycle phase, proliferation (number of cells) (flow cytometry)
• morphological/histopathological changes: cell morphology

Main outcome of study (according to author)
GSM-217 electromagnetic fields (EMF) induced a significant upregulation of mRNA levels of the heat shock protein, hsp70 of p53-deficient embryonic stem cells differentiating in vitro, paralleled by a low and transient increase of c-jun, c-myc, and p21 levels in p53-deficient, but not in wild-type cells. No responses were revealed in either cell type after electromagnetic field exposure to GSM-Talk applied at similar slot-averaged specific absorption rates (SAR), but at lower time-averaged SAR values. Cardiac differentiation and cell cycle characteristics were not affected in embryonic stem and embryonic carcinoma cells after irradiation to GSM-217 EMF signals. The results indicate that the genetic background determines cellular responses to GSM modulated EMF.

(Study character: medical/biological study, experimental study, full/main study)

Study funded by

• Fonds der chemischen Industrie (FCI; Foundation of the Chemical Industry), Germany
• VERUM Foundation (Stiftung für Verhalten und Umwelt), Germany

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