Abstract
The effects of ELF alternating magnetic fields tuned to Zn^2+^ on the growth of cancer cells with different status of p53 were investigated using a cell proliferation assay. Human cancer cells HeLa (cervix cancer, p53^+/+^), Saos‐2 and Saos‐2‐His‐273 (osteosarcoma, p53^−/−^ and p53 His‐273 mutant, respectively), H1299tTA and H1299tTA‐His175 (lung carcinoma, p53^−/−^ and p53 His‐175 mutant), and normal human fibroblasts VH‐10 (p53^+/+^) were used. Exposure parameters were calculated for the first harmonic of Zn^2+^ based either on the magnetic parametric resonance (MPR) model of Lednev or the ion parametric resonance (IPR) model of Blanchard and Blackman. ELF exposure was for 72 and 96 h. The vertical alternating field was 20 Hz at amplitudes of either 38.7 or 77.4 μT (peaks, IPR or MPR, respectively). The vertical static magnetic field was 43 μT, and the horizontal static magnetic field was zeroed. Treatments of cells with PRIMA‐1 and γ‐rays were used as positive controls. Growth inhibition was observed in cells after exposure to ELF at 38.7 μT. Inhibition of HeLa, VH‐10, and Saos‐2‐His‐273 cells was statistically significant, P = 0.0003, 0.02, and 0.006, respectively. No consistent ELF effects following exposure 77.4 μT were seen. PRIMA‐1 inhibited the growth of all cell lines with the strongest effect in mutant p53‐carrying cell line H1299tTA‐His175. The effects of γ‐rays were relatively weak, suggesting that the cell proliferation assay under conditions employed in this study is not very sensitive to apoptosis. In conclusion, ELF under conditions of exposure tuned to Zn^2+^ according to the IPR model inhibited the growth of cancer and normal cells. No clear relationship of the observed growth inhibition to p53 status was found. Further experiments, using complementary techniques, are required to test whether p53 reactivation by ELF is feasible. Bioelectromagnetics 26: 2005. © 2005 Wiley‐Liss, Inc.