Antagonistic effects of a 50 Hz magnetic field and melatonin in the proliferation and differentiation of hepatocarcinoma cells

Abstract

Background/Aims: Epidemiological and experimental evidence exists indicating that exposure to weak, extremely low frequency magnetic felds (ELF - MF) could affect cancer progression. It has been proposed that such hypothetical action could be mediated by MF-induced effects on the cellular response to melatonin (MEL), a potentially oncostatic neurohormone. The present study investigates the response of HepG2 cells to intermittent exposure to a 50 Hz, 10 μT MF, in the presence or absence of MEL at physiological (10 μM) or pharmacological doses (1 μM). Methods: The Trypan blue cell exclusion test, BrdU incorporation and PCNA expression assays were carried out to assess the cellular response in terms of viability and proliferation. In addition, albumin and alpha-fetoprotein, were analyzed as specifc hepatocellular differentiation markers. Results: The results indicate that the MF exerts signifcant cytoproliferative and dedifferentiating effects that can be prevented by 10. nM MEL. Conversely, MEL exerts cytostatic and differentiating effects on HepG2 that are abolished by simultaneous exposure to MF. Conclusion: As a whole, these results support the hypothesis that ELF - MF and MEL exert opposite, mutually counteracting effects on cell proliferation and differentiation. Copyright © 2012 S. Karger AG, Basel.