Medical/biological study (experimental study)

Changes in gene and protein expression in magnetic field-treated human glioma cells med./bio.

By: Savage Jr RE, Kanitz MH, Lotz WG, Conover D, Hennessey EM, Hanneman WH, Witzmann FA

Published in: Toxicol Mech Methods 2005; 15 (2): 115-120

Aim of study (acc. to author)

The possible carcinogenicity of magnetic fields should be investigated by examining the changes in gene expression and protein expression and their relationship in human glioma cells after an exposure to a 60 Hz magnetic field.

Background/further details

Triplicate sets of cell cultures were exposed to the magnetic field or to sham exposure, respectively. Biomarkers of carcinogens should be detected with protein expression analysis, while the parallel gene expression analysis should identify related oncogenes.

Endpoint

molecular biosynthesis: gene expression, protein expression

Exposure

- 60 Hz
- 50/60 Hz
- magnetic field
- low frequency

Exposure	Parameters
Exposure 1: 60 Hz Exposure duration: continuous for 3 h	magnetic flux density: 1.2 µT

Exposure 1

Main characteristics

Frequency	60 Hz
Type	magnetic field
Exposure duration	continuous for 3 h

Exposure setup

Exposure source	Helmholtz coils Merritt coils
Setup	two concentric Merrit/Helmholtz coil systems, inner coils for exposure, outer coils to limit stray fields; modified commercial incubator placed as exposure chamber in the coil system
Sham exposure	A sham exposure was conducted.
Additional info	for sham exposure: double-wound coils were energized with opposing currents so that the resulting magnetic field was zero

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	1.2 µT	-	-	-	-

Exposed system:

intact cell/cell culture
SF767 (human glioma cell line)

Methods Endpoint/measurement parameters/methodology

molecular biosynthesis: gene expression (oncogene microarray) protein expression (two-dimensional gel electrophoresis: isoelectric focusing followed by SDS-polyacrylamide gel electrophoresis), protein identification (peptide fingerprint, mass spectrometry)

Investigated system:

isolated bio./chem. substance
DNA/RNA
cell homogenate, proteins

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The results of gene expression analysis showed a significant up-regulation of five and down-regulation of 25 genes in cells exposed to the magnetic field compared to sham exposure. Protein expression analysis indicated that the expression rates of ten identified proteins were significantly altered. Three of these showed an increase and seven a decrease in their expression rate, following the exposure compared to sham exposure. However, no obvious relationship between the affected genes and proteins could be found.
The authors conclude that there is an effect of 60 Hz magnetic fields on gene expression and protein expression of human glioma cells, but that further studies are needed to clarify and evaluate the relationships.

Study character:

medical/biological study
experimental study
pilot/exploratory/preliminary study
blind study

Study funded by

not stated/no funding

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