Combination therapy of calcitriol inhibits the proliferation of breast cancer cells: new concept of nonclassical function of calcitriol

Abstract

Abstract Objectives To evaluate the anticancer effects of calcitriol and cholecalciferol against different cell lines of breast cancer in monotherapy settings and in combination with raloxifene. Methods The antiproliferative, anti-migratory, and apoptotic induction effects were assessed by MTT, wound healing, and flow cytometry assays, respectively. Results Calcitriol and cholecalciferol exhibited antiproliferative effects against T47D, MCF-7, and MDA-MB-231 in a time and concentration-dependent manner. The IC50 values of calcitriol were in the range of 0.05–0.25 μM while that for cholecalciferol were in the range of 3–100 μM. Furthermore, the results showed that calcitriol and cholecalciferol exhibited anti-migratory effects on MDA-MB-231, an apoptotic induction effect on MCF-7 cells, and a synergistic effect when combined with raloxifene. Conclusions Calcitriol and cholecalciferol exhibited anticancer effects and may be used as chemosensitizers.