Medical/biological study (experimental study)

Exposure of simian virus-40-transformed human cells to magnetic fields results in increased levels of T-antigen mRNA and protein med./bio.

By: Gold S, Goodman R, Shirley-Henderson A

Published in: Bioelectromagnetics 1994; 15 (4): 329-336

Aim of study (acc. to author)

This study was performed in order to examine the effects of an extremely low frequency magnetic field on viral gene expression in human host cells.

Background/further details

As marker of the viral gene expression SV40 was selected as its T-antigen (viral tumor antigen) gene expression can be clearly measured and distinguished from the host cell gene expression. Additionally, the introduction of a SV40 origin of DNA replication defective mutant in human fibroblasts (so called HAL cells) is known to increase the lifespan up to immortality. Therefore the use of HAL cells represents a model of carcinogenesis.
The negative controls were mouse fibroblast cell lines containing a defective strain of polyoma virus.

Endpoint

molecular biosynthesis: T-antigen gene expression/transcription and translation activity

Exposure

- 50/60 Hz
- magnetic field

Exposure	Parameters
Exposure 1: 60 Hz Exposure duration: continuous for 20 min	electric field strength: 10 µV/m average over time magnetic flux density: 8 µT peak value
Exposure 2: 60 Hz Exposure duration: continuous for 20 min	electric field strength: 38 µV/m maximum magnetic flux density: 8 µT peak value

Exposure 1

Main characteristics

Frequency	60 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	continuous for 20 min

Exposure setup

Exposure source	Helmholtz coils
Setup	The coils (13 cm long x 14 cm wide, 8 cm apart) were oriented vertically and generated a horizontal magnetic field. Six flasks were used for each experiment, three of which were exposed and the remaining three served as controls. Control cells were shielded in a µ-metal box and placed in the same incubator.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
electric field strength	10 µV/m	average over time	measured	-	-
magnetic flux density	8 µT	peak value	measured	-	-

Exposure 2

Main characteristics

Frequency	60 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	continuous for 20 min

Exposure setup

Exposure source	solenoid
Setup	The solenoid was constructed on on an acrylic tube 10.25 inches long with an inner diameter of 6.75 inches and generated a horizontal magnetic field. The exposure and control flasks were handled the same way as in E1.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
electric field strength	38 µV/m	maximum	measured	-	-
magnetic flux density	8 µT	peak value	measured	-	-

Reference articles

Goodman R et al. (1992): Exposure of human cells to electromagnetic fields: effect of time and field strength on transcript levels

Exposed system:

intact cell/cell culture
HAL cells (SV40 origin defective mutant transformed human fibroblast cell line)

Methods Endpoint/measurement parameters/methodology

molecular biosynthesis: T-antigen transcription (Northern blot, gel electrophoresis, autoradiography), T-antigen translation (Western blot, densitometry)

Investigated system:

isolated bio./chem. substance
DNA/RNA
protein

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The exposure of SV40-transformed human fibroblasts to an electromagnetic field showed increased levels of virally derived mRNA and protein of the T-antigen.
These data provide evidence that a foreign DNA integrated into host cells can be affected by electromagnetic fields.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Department of Energy, USA
Electric Power Research Institute (EPRI), USA
Electro-Biology, Parsippany, New York, USA
National Institute of Environmental Health Sciences (NIEHS), North Carolina, USA
Office of Naval Research (ONR), USA

Zhou J et al. (2002): Gene expression of cytokine receptors in HL60 cells exposed to a 50 Hz magnetic field
Morehouse CA et al. (2000): Exposure of Daudi cells to low-frequency magnetic fields does not elevate MYC steady-state mRNA levels
Tipping DR et al. (1999): Observations on the effects of low frequency electromagnetic fields on cellular transcription in Drosophila larvae reared in field-free conditions
Jahreis GP et al. (1998): Absence of 60-Hz, 0.1-mT magnetic field-induced changes in oncogene transcription rates or levels in CEM-CM3 cells
Pieroni L et al. (1998): Can a 50 Hz electromagnetic field influence the preintegrative steps of replication of a murine retrovirus responsible for leukemia/lymphoma?
Balcer-Kubiczek EK et al. (1998): BIGEL analysis of gene expression in HL60 cells exposed to X rays or 60 Hz magnetic fields
Jin M et al. (1997): Biological and technical variables in myc expression in HL60 cells exposed to 60 Hz electromagnetic fields
Harrison GH et al. (1997): Kinetics of gene expression following exposure to 60 Hz, 2 mT magnetic fields in three human cell lines
Lin H et al. (1996): Electromagnetic field stimulation of biosynthesis: changes in c-myc transcript levels during continuous and intermittent exposures
Balcer-Kubiczek EK et al. (1996): Rodent cell transformation and immediate early gene expression following 60-Hz magnetic field exposure
Miyakoshi J et al. (1996): Exposure to magnetic field (5 mT at 60 Hz) does not affect cell growth and c-myc gene expression
Goodman R et al. (1992): Exposure of human cells to electromagnetic fields: effect of time and field strength on transcript levels
Phillips JL et al. (1992): Magnetic field-induced changes in specific gene transcription
Goodman R et al. (1991): Transcription and translation in cells exposed to extremely low frequency electromagnetic fields

Exposure of simian virus-40-transformed human cells to magnetic fields results in increased levels of T-antigen mRNA and protein med./bio.

Aim of study (acc. to author)

Background/further details

Endpoint

Exposure

Exposure 1

Main characteristics

Exposure setup

Parameters

Exposure 2

Main characteristics

Exposure setup

Parameters

Reference articles

Methods Endpoint/measurement parameters/methodology

Main outcome of study (acc. to author)

Study funded by

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