Static and ELF magnetic fields induce tumor growth inhibition and apoptosis

TLDR

The study discusses the biophysical mechanisms underlying the observed effects of magnetic fields on tumor cells. In vitro experiments varied magnetic field intensity, frequency, and modulation on colon, breast, and fibroblast cell lines, and the most effective regimes were then applied subcutaneously to WiDr‑tumor‑bearing nude mice for 70 min daily over 4 weeks. Static and ELF magnetic fields >1 mT, especially modulated (static + 50 Hz ELF), induced apoptosis in colon and breast cancer cells and inhibited WiDr tumor growth by up to 50 % in nude mice without harming normal cells.

Abstract

The ability of static and extremely low frequency (ELF) Magnetic Fields (MF) to interfere with neoplastic cell function has been evaluated. In vitro experiments were carried out to study the role of MF characteristics (intensity, frequency, and modulation) on two transformed cell lines (WiDr human colon adenocarcinoma and MCF-7 human breast adenocarcinoma) and one nontransformed cell line (MRC-5 embryonal lung fibroblast). Increase in cell death morphologically consistent with apoptosis was reported exclusively in the two transformed cell lines. Cell-death induction was observed with MF of more than 1 mT. It was independent of the MF frequency and increased when modulated MF (static with a superimposition of ELF at 50 Hz) were used. Based on the in vitro results, four different MF exposure characteristics were selected and used to treat nude mice xenografted with WiDr cells. The treatment of nude mice bearing WiDr tumors subcutaneously. with daily exposure for 70 min to MF for 4 weeks caused significant tumor growth inhibition (up to 50%) by the end of the treatment when modulated MF were used for at least 60% of the whole treatment period and the time-averaged total MF intensity was higher than 3.59 mT. No toxic morphological changes induced by exposure were observed in renewing, slowly proliferating, or static normal cells. A discussion on the possible biophysical mechanism at the base of the observed biological results is also offered.