Effect Of YM155 And Homoharringtonine On Apoptosis And Autophagy Of K562 Cells

ObjectiveThis study was purposed to investigate the effect of YM155,a survivin inhibitor,on the apoptosis and autophagy of K562 cells and the effect of homoharringtonine(HHT)on mTOR signal pathway of K562 cells and its significance.Methods1.K562 cells were treated with YM155 at different concentration.Cell survival was analyzed by CCK-8 assay,cell apoptosis was detected by flow cytometry.Survivin,Bcl-2 and Beclin1 mRNA expressions were determined by RT-PCR.Survivin,Bcl-2,caspase-3,PARP and LC-3 protein expression were assayed by Western blot.2.K562 cells were treated with HHT at different concentration.Cell survival was analyzed by CCK-8 assay,cell apoptosis was detected by flow cytometry.mTOR,4E-BP1,p70S6 K and Beclin1 mRNA expressions were determined by RT-PCR.Caspase-3,Bcl-6,LC-3 and mTOR signal pathway related protein expressions were assayed by Western blot.Results1.The results of YM155:(1)YM155 inhibited K562 cells proliferation in a time and dose dependent mode.(2)With the increasing of YM155 concentration and action time,the expression levels of m RNA and protein of survivin and Bcl-2 were decreased,while the expression levels of caspase-3,PARP,Beclin1 and LC-3 wereincreased.(3)Compared with the YM155 group,the protein levels of LC-3 and caspase-3 were lower in YM155 united 3-MA group.2.The results of HHT:(1)HHT inhibit proliferation of K562 cells in a time dependent mode.(2)With the increasing of HHT concentration,the expression levels of mRNA and protein of mTOR,4E-BP1,p70S6 K and caspase-3 were increased,while the expression levels of Beclin1 and LC-3 were decreased.(3)Compared with the HHT group,the protein levels of mTOR signal pathway related protein and caspase-3 were lower and the levels of Bcl-6 and LC-3 were higher in HHT united rapamycin group.Conclusion1.YM155 can inhibit K562 cell proliferation by inducing apoptosis and autophagy,while autophagy induction effect can enhance its cytotoxic effect.2.HHT induces apoptosis of K562 cells by means of inhibiting autophagy and Bcl-6 expression through mTOR signal pathway.