25 Hz electromagnetic field exposure has no effect on cell cycle distribution and apoptosis in U-937 and HCA-2/1(cch) cells

It is reported that exposure to 50 Hz extremely low-frequency electromagnet ic field (ELF-EMF) can produce apoptosis and small variations in cell cycle distribution on different cell lines. In order to study the effect of ELF-EMF on tumoral cells in vitro, two cell lines (U-937, from a histiocytic lymphoma, and HCA-2/1(cch), from a human colon adenocarcinoma) were exposed to 25 Hz, 1.5 mT, for 2 h and 45 min. Ce ll cycle distribution, apoptosis (spontaneous and dexamethasone-induced) an d cell growth were evaluated. Neither significant alteration in cell cycle phases nor induction of apopto sis was observed. Nevertheless, the relative cell number was found to decre ase to 55.84 +/- 7.35% (p < 0.05, Student's t-test) for HCA-2/1(cch) cells after exposure to EMF in the presence of dexamethasone. The presence of dexamethasone during the EMF exposure could probably produc e a decrease in the cell growth of this cell line. (C) 2000 Elsevier Scienc e S.A. All rights reserved.