Study type: Medical/biological study (experimental study)

The Proliferative Response of NB69 Human Neuroblastoma Cells to a 50 Hz Magnetic Field is mediated by ERK1/2 Signaling. med./bio.

Published in: Cell Physiol Biochem 2012; 29 (5-6): 675-686

Aim of study (acc. to author)

To study whether a 50 Hz magnetic field can induce cell proliferation in the human neuroblastoma cell line NB69, and whether the signaling pathway MAPK-ERK1/2 is involved in that proliferative response.

Background/further details

The possible involvement of the transcription factor CREB in the proliferative response to the magnetic field was also investigated.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous or intermittent (5 min on/10 min off or 3 h on/3 h off) for up to 63 h

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Polarization
Exposure duration continuous or intermittent (5 min on/10 min off or 3 h on/3 h off) for up to 63 h
Additional info field perpendicular to the cell's growth surface
Exposure setup
Exposure source
Setup two pairs of Helmholtz coils set in two magnetically shielded conetic alloy chambers which were placed inside two identical CO2 incubators; cells in Petri dishes placed in the center of the coil system; only one set of coils was energized (samples in the unenergized set were considered as sham-exposed controls)
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 100 µT - - - -

Reference articles

  • Trillo MA et al. (2012): Influence of a 50 Hz magnetic field and of all-transretinol on the proliferation of human cancer cell lines.
  • Focke F et al. (2010): DNA fragmentation in human fibroblasts under extremely low frequency electromagnetic field exposure.
  • Ivancsits S et al. (2002): Induction of DNA strand breaks by intermittent exposure to extremely-low-frequency electromagnetic fields in human diploid fibroblasts.

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

The continuous exposure did not induce significant changes in cell proliferation. In contrast, both intermittent exposure to the 50 Hz magnetic field significantly stimulated cell proliferation in NB69 cells. The magnetic field exposure induced repeated transient activation of the MAPK- ERK1/2 signaling pathway, occurring early after the onset of each of the exposure cycles of the intermittent exposure (peak during "on"-interval).
When a specific inhibitor (PD98059) of the MAPK-ERK1/2 pathway was added to the culture medium, the early activation of ERK1/2 and the proliferative response observed subsequently, were blocked. From this, the authors conclude that activation of ERK1/2 is involved in the molecular mechanisms through which the 50 Hz magnetic field induces a proliferative response in NB69 cells. Additionally, the data showed that the magnetic field exposure also activated CREB, a downstream target of the MAPK- ERK1/2 pathway. However, such activation was independent of ERK1/2, suggesting that other pathways could be involved in the cellular and molecular response to the magnetic field.
These findings provide a further insight into the mechanisms through which weak, 50 Hz magnetic field could influence cancer-related processes in human cells.

Study character:

Study funded by

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