重楼皂苷D通过诱导凋亡及分化抑制K562细胞的增殖

Polyphyllin D inhibits proliferation of K562 on human leukemia cells by inducing apoptosis and differentiation

目的探讨重楼皂苷D对慢性粒细胞白血病细胞株K562的增殖抑制作用及其机制。方法四甲基偶氮唑蓝（MTT）法测定重楼皂苷D对K562细胞增殖抑制作用；流式细胞仪检测重楼皂苷D对K562细胞凋亡的影响；Western blotting检测相关蛋白的表达。结果重楼皂苷D对K562细胞有明显的增殖抑制作用，其作用24 h的半抑制浓度（IC50）值为（0.8±0.1）μmol/L；流式细胞仪检测结果显示，浓度为0、0.4、0.8、1.2 μmol/L重楼皂苷D作用K562细胞24 h后细胞凋亡率分别为（1.73±0.33）%、（14.47±2.57）%、（24.10±3.52）%、（31.51±4.09）%，呈依次增加趋势，差异有统计学意义（F=58.231，P＜0.001）。Western blotting结果显示，重楼皂苷D能够下调Bcl2的表达，上调Bax水平，使Bcl2/Bax比值明显降低，上调细胞色素c、活化caspase3表达。此外，重楼皂苷D能够明显上调细胞表面分化抗原CD14的表达，诱导细胞向单核巨噬细胞分化。结论重楼皂苷D能够明显抑制K562细胞增殖，其作用机制可能是通过诱导细胞凋亡及促进细胞分化实现的。

ObjectiveTo investigate the inhibitory effect of polyphyllin D on the proliferation of human chronic myelogenous leukemia （CML） cell line K562 cells and its mechanism. MethodsMethyl thiazolyl thiazolium （MTT） assay was used to evaluate the inhibition effect of polyphyllin D on the proliferation of K562 cells. Flow cytometry was used to determine the effect of polyphyllin D on the apoptosis of K562 cells. The related proteins were analyzed by Western blotting. ResultsThe MTT assay showed that polyphyllin D obviously inhibited the growth of K562 cells. The hemiinhibitory concentration （IC50） of 24 hours for the K562 cells was （0.8±0.1）μmol/L. Flow cytometric results demonstrated that polyphyllin D significantly induced apoptosis in a dosedependent manner, and the apoptosis rates of 0, 0.4, 0.8, 1.2 μmol/L polyphyllin D were （1.73±0.33）%, （14.47±2.57）%, （24.10±3.52）%, （31.51±4.09）% after 24 hours, with a significant difference （F=58.231, P〈0.001）. Western blotting showed that polyphyllin D significantly downregulated the expression of Bcl2, and this was accompanied by upregulation of Bax, decrease of the Bcl2/Bax ratio, upregulation of cytochrome c and activation of caspase3. Otherwise, polyphyllin D obviously induced monocyte differentiation by increasing CD14 expression on the surface of K562 cells. ConclusionPolyphyllin D can significantly inhibit the proliferation of K562 cells, and the mechanism may be realized by inducing apoptosis and promoting monocyte differentiation.