Abstract:
In vitro exposure to power frequency magnetic fields (MF) has been reported to influence cell proliferation and differentiation. However, the nature of the response of different human cancer cell types to these fields has not been sufficiently characterized. The present work investigates the response of two proliferating human cell lines of neuroblastoma (NB69) and hepatocarcinoma (HepG2) to a 42 h, intermittent treatment with a weak, 100 µT, 50 Hz MF, alone or in combination with 0.5 µM all-trans-retinol (ROL), a retinoid currently applied in oncostatic therapies. In each experimental replicate the cell samples were submitted to one of the following treatment combinations: MF+/ROL+, MF+/ROL-, MF-/ROL+ or MF-/ROL-. The proliferative response was determined by cell counting (Trypan blue exclusion), BrdU incorporation and by spectrophotometric analysis of total protein and DNA content. The results show that when administered separately, the two treatments, MF and ROL, significantly enhanced cell proliferation in both cell lines. In NB69 simultaneous administration of MF and ROL induced an additive effect on cell proliferation, associated to increased DNA content. By contrast, in HepG2 the ROL-induc...