Effects of Ursolic Acid on Proliferative Inhibition, Apoptotic Induction and Intracellular Free Ca2+ in Human Breast Carcinoma Cells

To investigate the effects of ursolic acid(UA) on proliferative inhibition, apoptotic induction, and the relationship between UA-induced apoptosis and intracellular Ca2+ concentration in human breast carcinoma(MCF-7) cells. After MCF-7 cells treated with UA in the concentrations from 5μmol/L to 40μmol/L UA for 24h, cell viability of proliferation was assessed by MTT assay. Treated MCF-7 cells with 10μmol/L, 20μmol/L, and 30μmol/L UA for 24h, the rates of cell apoptosis were examined by terminal deoxynucleotide transferase mediated dUTP nick-end-labeling method and flow cytometry with Annexin V/ propidium iodide fluorescent stain. Treated with 20μmol/L UA for 24h, intracellular Ca2+ concentration was measured by Fure-2 fluorescein load method. Treated with the concentrations from 10μmol/L to 40μmol/L UA, the rates of proliferative inhibition were increased significantly(P0.01). The degrees of the inhibition were in a dose-dependent fashion. IC50 of the proliferative inhibition was 36.18μmol/L. Treated with 10μmol/L, 20μmol/L and 30μmol/L UA, the rates of cell apoptosis were increased significantly(P0.01). Intracellular Ca2+ concentration after treatment with UA was significantly higher than that of control(P0.05). [Conclusion] Ursolic acid has the effects of inhibition to MCF-7 cell proliferation and induction of cell apoptosis. The apoptosis induced by UA may depend on rise of intracellular Ca2+ level in MCF-7 cells.