18β-glycyrrhetinic Acid-induced Apoptosis and Relation withIntracellular Ca2+ Release in Human Breast Carcinoma Cells

Objective: To study the effects of 18β-glycyrrhetinic acid (GA) on proliferation inhibition, apop- totic induction, and the relationship between GA-induced apoptosis and intracellular Ca2+ concentration in human breast carcinoma (MCF-7) cells. Methods: After MCF-7 cells were treated with GA at the concentrations from 50 μmol/L to 250 μmol/L for 24 h, cell viability of proliferation was assessed by MTT assay. After the cells were treated with 100 μmol/L, 150 μmol/L, and 200 μmol/L GA for 24 h, 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. After the cells treated with 150 μmol/L GA for 24 h, intracellular Ca2+ concentration was measured by Fure-2 fluorescein load method. Results: After the cells were treated with GA at the concentrations from 100 μmol/L to 250 μmol/L, the rates of proliferative inhibition were increased significantly (P<0.05 and P<0.01) in a dose- dependent fashion. IC50 of the proliferation inhibition was 234.33 μmol/L. Treated with 100 μmol/L, 150 μmol/L, and 200 μmol/L, the rates of cell apoptosis were increased significantly (P<0.01). Intracellular Ca2+ concentration after treatment with GA was higher evidently than that of control (P<0.05). Conclusion: 18β-glycyrrhetinic acid has the effects of the proliferation inhibition and the apoptotic induction on MCF-7 cells. The rise of intracellular Ca2+ level may be depended on apoptosis induced by GA in MCF-7 cells.