金丝桃素介导的光动力疗法在抑制白血病细胞株增殖中的机制研究

Mechanism of Photodynamic Therapy Mediated by Hypericin in Inhibiting the Proliferation of Leukemia Cell Lines

目的研究光活化后金丝桃素对白血病细胞增殖、凋亡的影响及其可能作用机制。方法荧光显微镜确定金丝桃素的入胞时间,运用四甲基偶氮唑蓝(MTT)技术检测金丝桃素对多种白血病细胞的增殖抑制作用,并计算其半抑制浓度(IC50);采用Annexin V-FITC/PI双标记法检测金丝桃素作用后白血病细胞的凋亡情况,Western blot方法检测Bax,Bcl-2以及caspase-3,8,9蛋白的含量变化。结果本实验探索了光活化后金丝桃素的最佳入胞时间为16 h。光活化后金丝桃素对多种白血病细胞的增殖具有抑制作用,且这种抑制作用具有明显的量效关系(r=0.990 5,P<0.01)。经金丝桃素作用后,白血病细胞发生了明显凋亡,Bax/Bcl-2蛋白比率明显升高,凋亡蛋白caspase-3,8,9被切割活化。结论金丝桃素通过caspase途径诱导细胞凋亡,从而有效抑制了多种白血病细胞株的增殖。

OBJECTIVE To observe the effects of hypericin on proliferation, apoptosis of leukemia cells and its possible mecha- nism. METHODS Subcellular localization of hypericin in leukemia cells by fluorescence microscopy. MTT （3-（4,5-dimethyl-2- thiazolyl）-2,5-diphenyl-2-H-tetrazolium bromide） test was adopted to observe the inhibitory effects of hyperiein on the proliferation of leukemia cells and calculated its half maximal inhibitory eoneentration（IC50）. The technology of flow cytometry, Annexin-V-FITC/ PI double stained method were employed to measure the cell apoptosis of leukemia cells after hypericin treatment. RESULTS The optimal time for hypericin to entry into cells was 16 h. Hypericin could inhibit the proliferation of leukemia cells in vitro, and the in- hibition presented obvious dose-effect relationship（ r = 0. 990 5, P 〈 0.01 ）. The apoptotic ratio of leukemia cells was gradually increased. The ratio of Bax/Bcl-2 was significantly increased, and the apoptotic protein caspase-3, 8, 9 is cleaved and activated. CONCLUSION Hypericin could inhibit the growth of leukemia cells, induce the apoptosis through induction of caspase dependent apoptosis pathway.