Ethyl acetate extract of Pleione bulbocodioides(Franch.)Rolfe induces apoptosis of human leukemia K562 and HL-60 cells through intrinsic mi-tochondrial apoptosis pathway / 中国病理生理杂志

ABSTRACT

AIM:To investigate the effects of ethyl acetate(EtOAc)extract of Pleione bulbocodioides (Franch.)Rolfe on proliferation and apoptosis of human leukemia K 562 and HL-60 cells and the possible apoptosis path-way.METHODS:Human leukemia cell lines were treated with EtOAc extract of Pleione bulbocodioides at different con-centrations.XTT method was used to evaluate the viability of K 562 cells and HL-60 cells.The cell growth inhibition was calculated by Trypan blue exclusion test.The percentage of apoptotic cells was determined by flow cytometry,and 4,,6-dia-midino-2-phenylindole(DAPI)was used to observe morphological changes of the cells.The cell cycle was observed by pro-pidium iodide(PI)staining.The protein expression of Bcl-2, Bax, cleaved poly(ADP-ribose)polymerase(PARP), cleaved caspase-3,cytochrome C and apoptosis-inducing factor(AIF)wase determined by Western blot.RESULTS:The cell viability and proliferation were inhibited by EtOAc extract of Pleione bulbocodioides with IC50of(42.14 ±2.54)mg/L for HL-60 cells and(51.28 ±3.12)mg/L for K562 cells at 24 h.The results of Annexin V-FITC/PI and DAPI staining showed that EtOAc extract of Pleione bulbocodioides induced cell apoptosis in a dose-dependent manner.The apoptotic rate was increased compared with control group(P<0.05).The G2phase increased with typical cell apoptosis-induced mor-phological changes.The levels of pro-apoptotic proteins Bax,cleaved PARP and cleaved caspase-3 were increased, while Bcl-2 was down-regulated(P<0.05).Cytochrome C and AIF in cytosol,characteristic proteins of intrinsic mitochondrial apoptosis pathway,also increased with the concentration of EtOAc extract of Pleione bulbocodioides increasing(P<0.05). CONCLUSION:EtOAc extract of Pleione bulbocodioides significantly inhibits cell proliferation and induces cell apoptosis in human leukemia cell lines HL-60 and K562 through intrinsic mitochondrial apoptosis pathway.