目的研究甘草次酸对髓系白血病细胞系K562体外增殖抑制作用,分析其引起细胞周期的变化及探讨其可能的抗癌机制。方法MTT法检测甘草次酸对K562细胞增殖活性的影响;Hoechst 33258染色法观察细胞凋亡形态学改变;流式细胞术分析细胞周期的变化以及cyclin D1和cyclin E蛋白表达的变化;RT-PCR测定细胞中cyclin D1和cyclin E mRNA表达的改变。结果甘草次酸对K562有增殖抑制作用,其抑制作用呈现为量效和时效依赖性,作用48 h的IC50值为(93.1±3.7)μmol/L。甘草次酸可以诱导细胞发生凋亡,Hoechst染色可见细胞核内凋亡小体。甘草次酸可以诱导K562细胞周期阻滞于G₀/G₁期,同时G₂/M期细胞比例减小,S期变化不明显,仅在最大浓度组稍有降低。甘草次酸可以同时下调K562细胞内cylin D1和cyclin E蛋白和基因的表达,下调作用与剂量呈正相关。结论甘草次酸能明显抑制K562细胞增殖,并诱导其周期阻滞于G₀/G₁期。该效应可能与其下调周期蛋白cyclin D1和cyclin E表达有关,有望成为新型抗肿瘤中药。

Objective To investigate the effects of glycyrrhetic acid(GA) on the proliferation in K562 cells in vitro and explore the possible mechanisms.Methods Cell proliferation was detected by MTT assay.Hoechst 33258 staining was used to evaluate the morphological changes in K562 cells induced by GA.The influence on cell cycle was studied by a propidium iodide method.Both flow cytometry(FCM) and RT-PCR techniques were applied to assess the expression of cyclin D1 and cyclin E proteins.ResultsGA presented the striking proliferation inhibition,as well as apoptosis induction potency on K562 cells in vitro in a time-and dose-dependent manner,with IC50 value for 48 h being(93.1±3.7) μmol/L.Moreover,cells treated with GA showed the accumulation in G0/G1 phase,reduction in the percentage of cells in G2/M phase and no significant change in S phase,except a little reducing in group with maximum concentration of GA.The contents of cyclin D1 and cyclin E were found to be downregulated at both protein and gene levels in K562 cells in a dose-dependent manner when treated with various concentrations of GA.Conclusion GA presents the potent inhibition on proliferation of K562,induction on apoptosis,and cell-cycle arrest in leukemia cells in G0/G1 phase,which might correspond to the down regulation of the expression of cyclin D1 and cyclin E.GA,as a Chinese materia medica,indicates a potential for acute leukemia.

国家自然科学基金资助项目(30572440)