Almost all enzymes contain ions such as magnesium, calcium, and zinc, which are important for the stability of conformation of these proteins and their enzyme activity. According to several models, extremely low frequency magnetic fields affects cells through an influence on unhydrated ions inside proteins if parameters of exposure are tuned to these ions (see publication 257 and publication 2404).
One potential Zn2+-containing target for magnetic fields is the p53 protein. Binding of Zn2+ by p53 is required both for the conformation stability of p53 and for its sequence-specific DNA binding. Removal of Zn2+ abolishes DNA site-specific activity (and thus functionally inactivates p53).
It was investigated whether modulation of Zn2+ by extremely low frequency magnetic fields as based on IPR (ion parametric resonance model, see publication 2404) and MPR (magnetic parametric resonance model, see publication 1176) models can affect the growth of human cancer cells with different status of p53: wild type, deleted, mutant.
Treatments of cells with PRIMA-1 (p53 reactivation and induction of massive apoptosis; restores DNA-binding activity) and gamma rays were used as positive controls.
Exposure duration: continuous for 72 und 96 h
Exposure duration: continuous for 72 und 96 h.
|Chamber||Each ELF exposure unit was based on three orthogonal pairs of Helmholtz-circular coils, which produced relatively homogeneous (5%) magnetic fields inside the working volume. The vertical coils were oriented in the north-south direction.|
|Setup||Exposures and sham exposures were performed simultaneously, using two identical ELF exposure units. In each experiment,exposure and sham exposure of four 96-well plates were simultaneously performed in identical Helmholtz coils under the same temperature, humidity, CO2 concentration, DC magnetic field, and background ELF magnetic field.|
|Additional info||Treatments of cells with PRIMA-1 and gamma-rays were used as positive controls.|
Growth inhibition was revealed after exposure to extremely low frequency magnetic field at 38.7 µT. Inhibition of HeLa, VH10, and Saos-2-His-273 cells was statistically significant. No consistent extremely low frequency magnetic field effects following exposure at 77.4 µT were found.
PRIMA-1 inhibited the growth of all cell lines with the strongest effect in mutant p53-carrying cell line H1299tTA-His175. The effects of gamma-rays were relatively weak, indicating that the cell proliferation assay under conditions employed in this study is not very sensitive to apoptosis.
In conclusion, extremely low frequency magnetic field exposure tuned to Zn2+ (according to the IPR model) inhibited the growth of cancer and normal cells. No clear relationship of the revealed growth inhibition to p53 status was found.