Polyphyllin D inhibits proliferation of K562 on human leukemia cells by inducing apoptosis and differentiation / 国际肿瘤学杂志

ABSTRACT

Objective To investigate the inhibitory effect of polyphyllin D on the proliferation of human chronic myelogenous leukemia (CML) cell line K562 cells and its mechanism.Methods Methyl 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.Results The 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.Conclusion Polyphyllin D can significantly inhibit the proliferation of K562 cells,and the mechanism may be realized by inducing apoptosis and promoting monocyte differentiation.