To study whether exposure to a sinusoidal extremely low frequency magnetic field (50 Hz, 1 mT) can affect cell proliferation and cell differentiation in the human neuroblastoma cell line BE(2)C, which is representative of high risk neuroblastomas.
Cells were subjected to extremely low frequency magnetic field exposure in the presence or absence of a neuronal differentiating agent (all-trans-retinoic acid, ATRA) for 24-72 h (ATRA treated BE(2)C cells show a decrease in cell proliferation rate and neurite outgrowth).
The effects of magnetic fields on neural differentiation should be investigated in view of possible biomedical applications; induction of cell differentiation is a purpose in the care of tumors, since the less a tumor is differentiated, the higher its metastatic aggressiveness. In high-risk neuroblastoma therapy, retinoic acid is sometimes used because of its ability to induce growth arrest and differentiation. The authors hypothesize that magnetic field exposure could improve the differentiation of low-responsive neuroblastomas to ATRA.
Exposure duration: continuous for 24 hr to 72 hr
|Setup||two pairs of Helmholtz coils in a 5% CO2 incubator at a constant temperature of 37°C; coils with a diamter of 25 cm and 2 x 20 turns double wrapped; 11 cm high exposure area with a diamter of 4 cm in the center of the coil system|
|Sham exposure||A sham exposure was conducted.|
|magnetic flux density||1 mT||-||measured||-||-|
Cells exposed to extremely low frequency magnetic fields combined with retinoic treatment (ATRA) showed a decreased cell proliferation and an increased proportion of G0 phase/G1 phase cells compared to cells exposed to either treatment alone. Moreover, the cells subjected to the magnetic field in combination with ATRA treatment showed an increase in the neurite outgrowth number and length compared to cells subjected to either treatment alone. Additionally, a significant increase of gene expression of p21WAF1/CPP1 and cdk5 genes was found. Cyp19 gene expression was enhanced by ATRA treatment and significantly enhanced further by extremely low frequency magnetic field exposure combined with ATRA.
In conclusion, the data suggest that extremely low frequency magnetic field exposure can strengthen ATRA effects on neuroblastoma cells.