甘草酸诱导人乳腺癌细胞凋亡和细胞内Ca^(2+)的相关性研究

Study on relationship between glycyrrhizin-induced apoptosis and intracellular Ca^(2+) concentration in human breast carcinoma cells

目的探讨甘草酸对人乳腺癌细胞(MCF-7)增殖抑制和诱导凋亡的作用,了解凋亡发生与细胞内Ca2+的相关性。方法MTT比色法测定细胞增殖能力,末端脱氧核苷酸转移酶介导dUTP末端标记法、An-nexinV流式细胞仪法和单细胞凝胶电泳(彗星试验)法检测凋亡细胞,Fura-2荧光负载方法测定[Ca2+]i的变化。结果从5mmol/L甘草酸浓度起对MCF-7细胞的增殖抑制率显著升高(P<0.01),呈剂量依赖性,半增殖抑制浓度(IC50)为15.84mmol/L。7.5mmol/L和10.0mmol/L甘草酸使细胞凋亡率显著升高(P<0.05和P<0.01)。甘草酸处理组的[Ca2+]i明显低于对照组(P<0.05)。甘草酸与BAPTA-AM组合处理组的凋亡率明显高于单纯的7.5mmol/L处理组(P<0.05和P<0.01)。结论甘草酸具有抑制MCF-7细胞增殖和诱导其凋亡的作用;其诱导凋亡可能与细胞内Ca2+水平下调有关。

[Objective] To investigate the effects of glycyrrhizin (GL) on proliferative inhibition, apoptotic induction, and the relationship between GL-induced apoptosis and intracellular Ca2+ concentration in human breast carcinoma (MCF-7) cells. [Methods] Cell viability of proliferation was assessed by MTT assay. The rates of cell apoptosis were examined by terminal deoxynucleotide transferase mediated dUTP nick-end-labeling method, flow cytometry with Annexin V/propidium iodide fluorescent stain and single cell gel electrophoresis assay (SCGE). intracellular Ca2+ concentration was measured by Fure-2 fluorescein load method. [Results] Treated with the concentrations from 5 mmol/L to 12.5 mmol/L GL, the rates of proliferative inhibition were increased significantly (P<0.01), the degrees of the inhibition were in a dose-dependent fashion. IC50 of the proliferative inhibition was 15.84mmol/L. Treated with 7.5 mmol/L and 10 mmol/L GL, the rates of cell apoptosis were increased significantly (P<0.05 and P<0.01). Intracellular Ca2+ concentration of treatment with GL was lower evidently than that of control(P<0.05). The rate of cell apoptosis after treatment with the combination of GL and BAPTA-AM or EGTA was lower markedly than that treated with a single GL (P <0.05 and P <0.01). [Conclusion] Glycyrrhizin has the effects of the inhibition of MCF-7 cell proliferation and induction of the cell apoptosis. The descent of intracellular Ca2+ level may be depended on during apoptosis induced by GL in MCF-7 cells.