Medical/biological study (experimental study)

A 60-Hz sinusoidal magnetic field induces apoptosis of prostate cancer cells through reactive oxygen species med./bio.

By: Koh EK, Ryu BK, Jeong DY, Bang IS, Nam MH, Chae KS

Published in: Int J Radiat Biol 2008; 84 (11): 945-955

Aim of study (acc. to author)

To study the effects of power frequency magnetic fields on cell growth in different prostate cancer cell lines and the underlying mechanisms for these effects.

Background/further details

The cells were exposed to various intensities and durations of 60 Hz sinusoidal magnetic field in combination with various concentrations of serum, caspase-3 inhibitor, or N-acetyl-L-cysteine (as antioxidant) in the media.

Endpoint

cell viability/cell division/proliferation: cell growth, cell death/apoptosis, cell cycle

Exposure

Exposure	Parameters
Exposure 1: 60 Hz Exposure duration: continuous for 24 h for serveral days - possibly up to 4 days - not exactly stated	magnetic flux density: 0.2 mT minimum magnetic flux density: 0.5 mT magnetic flux density: 1 mT magnetic flux density: 2.5 mT maximum

General information

In some experimental sets, a certain percentage of serum, Caspase-3 inhibitor, or NAC at various concentrations was added to the serum-free medium 1h or 2 h before MF exposure.

Exposure 1

Main characteristics

Frequency	60 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	continuous for 24 h for serveral days - possibly up to 4 days - not exactly stated

Exposure setup

Exposure source	Helmholtz coils
Setup	28 cm x 28 cm x 30 cm rectangular Helmholtz coils on open acrylic frames with three bundles (2000 turns per bundle) of 0.5 mm copper wire, aligned parallel, 20 cm apart
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	0.2 mT	minimum	measured	-	-
magnetic flux density	0.5 mT	-	measured	-	-
magnetic flux density	1 mT	-	measured	-	-
magnetic flux density	2.5 mT	maximum	measured	-	-

Exposed system:

intact cell/cell culture
different human prostate carcinoma cell lines (DU145, LNCaP, PC3)

Methods Endpoint/measurement parameters/methodology

molecular biosynthesis: caspase-3 expression (Western blot); reactive oxygen species formation (spectrofluorometry)
cell viability/cell division/proliferation: cell growth (cell counting); cell death/apoptosis (trypan blue exclusion test); cell cycle analysis (flow cytometry)

Investigated system:

isolated bio./chem. substance
intact cell/cell culture
cell lysates

Time of investigation:

after exposure

Main outcome of study (acc. to author)

In the three prostate cancer cells, magnetic field exposure inhibited cell growth and significantly promoted apoptosis and cell cycle arrest proportional to the intensity and duration of the magnetic field. Cleaved caspase-3, and reactive oxygen species increased. Pretreatment with a caspase-3 inhibitor or the antioxidant N-acetyl-L-cysteine significantly attenuated magnetic field induced cell growth inhibition and cell death. Media replacement experiments failed to show any notable change in the magnetic field effects.
The data suggest that a possibility of using 60 Hz magnetic field in radiation therapy of prostate cancer could usefully be investigated.

Study character:

medical/biological study
experimental study
full/main study
blind study

Study funded by

Korea Research Foundation (KRF), Korea
Kyungpook National University Research Fund, Korea

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