Inhibition of cancer cell growth by exposure to a specific time-varying electromagnetic field involves T-type calcium channels.

Carly A Buckner,Robert M Lafrenie,Michael A Persinger,Alison L Buckner,Stan A Koren,Steven Barnes

doi:10.1371/journal.pone.0124136

Carly A Buckner, Robert M Lafrenie + Show 4 more

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https://doi.org/10.1371/journal.pone.0124136

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Abstract

Electromagnetic field (EMF) exposures affect many biological systems. The reproducibility of these effects is related to the intensity, duration, frequency, and pattern of the EMF. We have shown that exposure to a specific time-varying EMF can inhibit the growth of malignant cells. Thomas-EMF is a low-intensity, frequency-modulated (25-6 Hz) EMF pattern. Daily, 1 h, exposures to Thomas-EMF inhibited the growth of malignant cell lines including B16-BL6, MDA-MB-231, MCF-7, and HeLa cells but did not affect the growth of non-malignant cells. Thomas-EMF also inhibited B16-BL6 cell proliferation in vivo. B16-BL6 cells implanted in syngeneic C57b mice and exposed daily to Thomas-EMF produced smaller tumours than in sham-treated controls. In vitro studies showed that exposure of malignant cells to Thomas-EMF for > 15 min promoted Ca2+ influx which could be blocked by inhibitors of voltage-gated T-type Ca2+ channels. Blocking Ca2+ uptake also blocked Thomas-EMF-dependent inhibition of cell proliferation. Exposure to Thomas-EMF delayed cell cycle progression and altered cyclin expression consistent with the decrease in cell proliferation. Non-malignant cells did not show any EMF-dependent changes in Ca2+ influx or cell growth. These data confirm that exposure to a specific EMF pattern can affect cellular processes and that exposure to Thomas-EMF may provide a potential anti-cancer therapy.

Highlights

Several studies have shown associations between electromagnetic field (EMF) exposure and health effects, such as cancer incidence; the conclusions of these studies are sometimes difficult to reproduce and are controversial
Exposure of B16-BL6 mouse melanoma cell cultures to Thomas-EMF inhibited their proliferation by 45±6% after 5 days compared to sham-exposed cells (Fig 2A)
Non-malignant cell lines, HBL-100 breast cells, HEK293 kidney cells, and HSG salivary gland cells, to Thomas-EMF had no effect on cell proliferation

Summary

Introduction

Several studies have shown associations between electromagnetic field (EMF) exposure and health effects, such as cancer incidence; the conclusions of these studies are sometimes difficult to reproduce and are controversial. It is difficult to make direct associations between EMF exposure and health effects, since not all EMFs are equivalent [1]. EMF Inhibits Cancer Cell Proliferation altered the authors' adherence to the PLOS ONE editorial policies and criteria. While most studies have focussed on the negative effects of EMF, specific EMFs have been shown to accelerate wound healing, enhance musculoskeletal recovery, and disrupt tumor growth [2,3,4]. Some investigators have proposed that non-specific processes such as the generation of heat, formation of free-radicals, and promotion of DNA damage are involved [5,6,7]. The energies typically associated with low frequency EMF are not sufficient to cause changes in chemical bonds and other models including ion resonance have been proposed [8,9]

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