Study type: Medical/biological study (experimental study)

Effects of PEMF on a murine osteosarcoma cell line: drug-resistant (P-glycoprotein-positive) and non-resistant cells med./bio.

By: Miyagi N, Sato K, Rong Y, Yamamura S, Katagiri H, Kobayashi K, Iwata H
Published in: Bioelectromagnetics 2000; 21 (2): 112-121
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Aim of study (acc. to editor)

To investigate the effects of pulsating electromagnetic fields (PEMF) on the growth of murine osteosarcoma (resistent and non-resistent to ADR) in combination with the anti tumor agent Adriamycin (ADR) and human fibroblast cells in vitro.

Background/further details

Self-prepared resistent osteosarcoma cells expressed P-glycoprotein and had resistance to ADR more than 10 times that of their nonresistant parent cells. P-glycoprotein is considered to be clinically the most important factor associated with the ineffectiveness of chemotherapy against metastasis.
The authors expected, that, if the growth of well-differentiated cells (e.g. fibroblast cells) is inhibited by exposure to PEMF under certain conditions, the growth of well-differentiated drug-resistant cells may also be suppressed by exposing them to PEMF under the same conditions. Moreover, the growth of undifferentiated cells may also be promoted in the same manner. These phenomena, if confirmed, will be evidence that PEMF is effective to control drug resistance.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 10 Hz
Modulation type: pulsed
Exposure duration: 72 h

Exposure 1

Main characteristics
Frequency 10 Hz
Type
Waveform
Exposure duration 72 h
Modulation
Modulation type pulsed
Additional info

25 µs magnetic field transition time
Exposure setup
Exposure source
Distance between exposed object and exposure source 0.05 m
Setup coil with a diameter of 10 cm formed by a flat 6 cm thick cable with a diamter of 18 cm; dishes placed in the center of this coil
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 800 µT maximum cf. remarks - 400 to 800 µT

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Exposure to PEMF, promoted the growth of nonresistant cells in an ADR-free medium but supressed the growth of more differentiated resistant cells, which expressed P-glycoprotein, and of human fibroblasts.
Exposure to PEMF supressed the growth of nonresistant cells incubated in media containing ADR at the IC50 (0.03 µg/ml) or above.
Furthermore, it inhibited the growth of P-glycoprotein positive resistant cells incubated in all ADR-containing and ADR-free media.
The data suggest that PEMF promotes the growth of undifferentiated cells but progressively suppresses the growth of more differentiated cells, i.e., PEMF controls cell growth depending on the degree of cell differentiation. Thus, the findings show the potentiality of PEMF as an adjunctive treatment method for malignant tumors.

Study character:

Study funded by

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