The proliferation rates of HT-1080 human fibrosarcoma cells can be accelerated or inhibited by weak static and extremely low frequency magnetic fields.

INTRODUCTION: Weak static and low-frequency magnetic fields (MFs) have been hypothesized to influence biological systems through mechanisms involving nuclear spin coupling. This study investigates how such fields modulate the proliferation of HT-1080 fibrosarcoma cells. METHODS: HT-1080 cells were exposed in vitro for 4 days to weak MFs with a 10 μT amplitude and frequencies between 12 Hz and 33 Hz, superimposed on a 45 μT static background field. Changes in cell growth, mitochondrial superoxide (O(2) (-)), calcium ion (Ca(2+)) concentrations, and membrane potential were measured. RESULTS: Results revealed that MFs could either increase or decrease fibrosarcoma cell growth in a frequency- and amplitude-dependent manner. Inversions in growth rates were observed near 16.5 Hz, where a 0.5 Hz shift or amplitude changes as small as 250 nT reversed effects relative to controls. Reversing the static field direction also inverted growth outcomes. Changes in membrane potential, Ca(2+), and mitochondrial superoxide levels supported a role for bioenergetic modulation. DISCUSSION: These findings suggest that weak MFs affect cell proliferation through spin-dependent chemical reaction rate changes. The pronounced sensitivity of fibrosarcoma cells compared to normal fibroblasts points to potential therapeutic applications via selective MF-based modulation.