Abstract:

Background and Aims: 1,25(OH)2D3 (vitamin D) is a pleiotropic hormone with anti-proliferative, pro-apoptotic, and pro- differentiation effects on various cell types, which suggest anti-cancer activity in addition to its classical regulatory action on calcium and phosphate metabolism. Methods: We aimed to put forward the effects of vitamin D in various concentrations and time intervals on cell proliferation and invasion of human estrogen receptor-positive breast cancer (MCF-7) cells by real-time cell electronic sensing system (xCELLigence). A determined dose of the IC50 was applied on samples taken from cell lysates and analyzed the levels of the energy. We also aimed to clarify how vitamin D effects the activity of the protease uPA and their relations with each other. Results: Vitamin D showed a cytotoxic effect on MCF-7 cells in a time and dose dependent manner, with dose of IC50 found to be 140 nM. ATP, ADP, and AMP levels, as well as uPA activities were respectively increased in vitamin D treatment group compared to the control group for the first 24 hours while decreasing at 48, 72, and 96 hours. We determined that 70 and 140 nM vitamin D were decreased in invasion of MCF-7 cells compared to control cells. Conclusion: We observed that proliferation and invasion of breast cancer cells were inhibited by vitamin D treatment on a dose and time dependent manner, and also vitamin D supplementation decreased uPA activity and energy levels. Further studies on the mechanisms of vitamin D and the formulation of none-hypercalcemic analogues in featured are needed.

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