Characterization of ornithine decarboxylase activies of human breast cancer cells (MCF-7) and spontaneously immortalized human mammary cells (MCF-10).
Zhu-H; Mathias-PI; Lotz-WG; Savage-RE
Proceedings of the Eighty-Ninth Annual Meeting of the American Association for Cancer Research, March 28 - April 1, 1998, New Orleans, Louisiana. Philadelphia, PA: American Association for Cancer Research, 1998 Mar-Apr; 39:409
Epidemiological studies suggest that increased risk of breast cancer is associated with exposures to electromagnetic fields (EMFs). EMFs have been demonstrated to increase Ornithine decarboxylase (ODC) activity in a variety of experimental systems. ODC, the rate limiting enzyme in polyamine synthesis, has been associated with chemical carcinogenesis. Very few if any studies have examined the effects of EMFs on breast cell ODC. Preliminary to our studies of EMF on ODC in human breast cancer cells (MCF-7) and spontaneously immortalized human mammary cells (MCF-10), we attempted to characterize the enzyme's response to a number of common ODC inducers. For the MCF-7 cells, time course studies suggested that ODC activity began to increase at 6 h, peaked at 12 h and then dropped sharply by 24 h. Treatment with 50 nM 12-O-tetradecanoylphorbol-13-acetate (TPA) for 12 h, ODC activity could be induced over 100 folds over the basal level. 9, 10 Dimethyl 1,2 benzanthracene (DMBA) also induced ODC activity of MCF-7 cells in similar manner. In contrast, ODC activity was barely detectable, and was not induced by TPA or DMBA with concentration up to 400 nM in MCF-10A cells. The finding that melatonin, a cytostatic agent induced ODC activity was also peculiar. Melatonin induced ODC activity significantly in MCF-7 cells with 1 nM concentration at 12h. Studies are underway to determine the effects of EMF on the ODC activity of these and other breast cancer cells lines.
Breast-cancer; Cancer; Epidemiology; Risk-analysis; Risk-factors; Electromagnetic-fields; Exposure-levels
Abstract; Conference/Symposia Proceedings
Proceedings of the Eighty-Ninth Annual Meeting of the American Association for Cancer Research, March 28 - April 1, 1998, New Orleans, Louisiana