Studies of the interactions between melatonin and 2 Hz, 0.3 mT PEMF on theproliferation and invasion of human breast cancer cells

Interactions between the hormone melatonin at pharmacological concentration s (10(-3) M) and 2 Hz, 0.3 mT pulsed electromagnetic fields (PEMF) on the p roliferation and invasion of human breast cancer cells were studied in vitr o. Three types of human breast cancer cells were used in this study: MDA-MB -435, MDA-MB-231, and MCF-7. Results showed that cellular growth of MDA-MB- 231 cells, which were reported to be lowly metastatic, and MCF-7 cells, whi ch were reported to be nonmetastatic, were both significantly reduced by me latonin regardless of the presence of the field. Results also showed that M DA-MB-435 and MDA-MB-231 cells were invasive, with MDA-MB-231 cells being m ore invasive than the MDA-MB-435 cells for both unexposed and experimental- PEMF groups. In addition, invasion studies showed that MCF-7 cells were not invasive and that melatonin did not have any effects on the invasion of th ese cells, with or without the PEMF. It is also suggested that since metast asis requires growth and invasion into tissue, anti-invasion agents can be used in conjunction with melatonin to prevent formation of secondary metast ases. The overall studies suggest that PEMF at 2 Hz, 0.3 mT does not influe nce cancer metastasis; while having clinical merit in the healing of soft t issue injury, this field has shown no influence on cancer cells as 60 Hz po wer line fields have. (C) 2001 Wiley-Liss, Inc.