Medical/biological study (experimental study)

Proto-oncogene mRNA levels and activities of multiple transcription factors in C3H 10T 1/2 murine embryonic fibroblasts exposed to 835.62 and 847.74 MHz cellular phone communication frequency radiation med./bio.

By: Goswami PC, Albee LD, Parsian AJ, Baty JD, Moros EG, Pickard WF, Roti Roti JL, Hunt CR

Published in: Radiat Res 1999; 151 (3): 300-309

Aim of study (acc. to author)

To determine whether two different modulated radiofrequencies of the type generally used in cellular phones (835.62 MHz (FMCW) and 835.62 MHz (CDMA)) could elicit a general stress response in a biological system.

Background/further details

Changes in proto-oncogene expression, determined by measuring Fos, Jun, and Myc mRNA levels as well as by the DNA-binding activity of the AP1, AP2 and NFkB transcription factors, were used as indicators of a general stress response.

Endpoint

molecular biosynthesis: stress response (proto-oncogene expression and DNA-binding activity of transcription factors)

Exposure

- CDMA
- mobile communications

Exposure	Parameters
Exposure 1: 835.62 MHz Exposure duration: continuous for 24 h or 4 days FMCW	SAR: 0.6 W/kg mean (± 0.3 W/kg)
Exposure 2: 847.74 MHz Exposure duration: continuous for 24 h or 4 days CDMA	SAR: 0.6 W/kg mean (± 0.3 W/kg)

Exposure 1

Main characteristics

Frequency	835.62 MHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 24 h or 4 days
Additional info	FMCW

Modulation

Modulation type	cf. additional info
Additional info	FMCW

Exposure setup

Exposure source	radial waveguide
Chamber	A detailed description of the radial transmission line (RTL) and a temperature-controlled facility containing nine RTLs has been given in the reference articles. The RTL is a shielded irradiator consisting of a parallel-plate region (43 mm spacing, total radius of 533 mm) with the bottom aluminium plate acting as a thermal homogenizer for the flasks. A central conical antenna (203 mm in diameter) emitted TEM waves radially outward that were terminated by RF-absorbing material backed by a lamina of perforated aluminium.
Setup	A total of 16 T-75 culture flasks each containing 40 ml of medium could be distributed angularly around the antenna. The cell layer in the flasks was subjected to a perpendicular EF and a circumferential MF perpendicular to the EF and the direction of propagation inducing a radial component to the EF.
Sham exposure	A sham exposure was conducted.
Additional info	Sham exposures were performed in an identical RTL without the RF field. The temperature of the culture medium was maintained at 37.0 ± 0.25°C by feedback controllers for each RTL.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	0.6 W/kg	mean	estimated	-	± 0.3 W/kg

Measurement and calculation details

An extensive analytical, numerical and experimental evaluation was carried out using both thermometric and thermographic techniques to map power deposition distributions (see reference article on dosimetry). The larger than usual amount of culture medium (40 instead of 15 ml) was needed to reduce SAR non-uniformities. Results from a fast temperature differential thermometry measurement on a fully loaded RTL at 835.62 MHz were used for estimating the SAR for the input power applied to the RTL during the experiments. The high-SAR region at the centre of the flask was 1.5 dB higher and the low-SAR regions were approx. 3 dB lower than the average SAR for a typical flask.

Exposure 2

Main characteristics

Frequency	847.74 MHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 24 h or 4 days
Additional info	CDMA

Modulation

Modulation type	cf. additional info
Additional info	CDMA

Exposure setup

Exposure source	same setup as exposure 1

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	0.6 W/kg	mean	estimated	-	± 0.3 W/kg

Reference articles

Moros EG et al. (1999): The radial transmission line as a broad-band shielded exposure system for microwave irradiation of large numbers of culture flasks
Moros EG et al. (1999): Compact shielded exposure system for the simultaneous long-term UHF irradiation of forty small mammals. II. Dosimetry

Exposed system:

intact cell/cell culture
C3H 10T1/2 cells (derived from mouse embryo fibroblasts)

Methods Endpoint/measurement parameters/methodology

molecular biosynthesis: Fos, Jun, and Myc mRNA levels (RT-PCR); DNA-binding activity of the AP1, AP2 and NFkB transcription factors (gel mobility shift assay)

Investigated system:

DNA/RNA
DNA-protein complex

Time of investigation:

after exposure

Main outcome of study (acc. to author)

Exposure of cells to a FMCW or CDMA field did not result in any significant variation in Jun and Myc mRNA levels or the DNA-binding activities of AP1, AP2, and NFkB.
Thus it is concluded that it is unlikely that the radiofrequency field is capable of eliciting a general stress response in cells of this cell line. However, the statistically significant increase in Fos expression suggests that the radiation could affect expression of specific genes.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Motorola
National Institutes of Health (NIH), Maryland, USA

Replication studies

Whitehead TD et al. (2005): Expression of the proto-oncogene Fos after exposure to radiofrequency radiation relevant to wireless communications

Yan JG et al. (2008): Upregulation of specific mRNA levels in rat brain after cell phone exposure
Zhao TY et al. (2007): Exposure to cell phone radiation up-regulates apoptosis genes in primary cultures of neurons and astrocytes
Chauhan V et al. (2007): Analysis of gene expression in two human-derived cell lines exposed in vitro to a 1.9 GHz pulse-modulated radiofrequency field
Belyaev IY et al. (2006): Exposure of rat brain to 915 MHz GSM microwaves induces changes in gene expression but not double stranded DNA breaks or effects on chromatin conformation
Chauhan V et al. (2006): Gene Expression Analysis of a Human Lymphoblastoma Cell Line Exposed In Vitro to an Intermittent 1.9 GHz Pulse-Modulated Radiofrequency Field
Whitehead TD et al. (2006): Gene expression does not change significantly in C3H 10T(1/2) cells after exposure to 847.74 CDMA or 835.62 FDMA radiofrequency radiation
Chauhan V et al. (2006): Analysis of proto-oncogene and heat-shock protein gene expression in human derived cell-lines exposed in vitro to an intermittent 1.9 GHz pulse-modulated radiofrequency field
Whitehead TD et al. (2006): The number of genes changing expression after chronic exposure to Code Division Multiple Access or Frequency DMA radiofrequency radiation does not exceed the false-positive rate
Whitehead TD et al. (2005): Expression of the proto-oncogene Fos after exposure to radiofrequency radiation relevant to wireless communications

Proto-oncogene mRNA levels and activities of multiple transcription factors in C3H 10T 1/2 murine embryonic fibroblasts exposed to 835.62 and 847.74 MHz cellular phone communication frequency radiation med./bio.

Aim of study (acc. to author)

Background/further details

Endpoint

Exposure

Exposure 1

Main characteristics

Modulation

Exposure setup

Parameters

Measurement and calculation details

Exposure 2

Main characteristics

Modulation

Exposure setup

Parameters

Reference articles

Methods Endpoint/measurement parameters/methodology

Main outcome of study (acc. to author)

Study funded by

Replication studies

Related articles