| Objective:To investigate the synergy mechanism of ganetespib and triptolide in human leukemia cell lines.Methods:（1）MTT assay was used to assess cell proliferous inhibition of ganetespib and triptolide in human leukemia cell K562 and HL-60 in vitro.（2）Synergy between ganetespib and triptolide was evaluated using the CompuSyn software.（3）Western blot was applied to reveal the related protein level.（4）The apoptotic effect was detected by flow cytometry via Annexin V-FITC/PI double staining.Results:（1）Ganetespib and triptolide inhibited cell proliferation in human leukemia cell lines K562 and HL-60 in dose-dependent manner,with IC50 of（0.0486±0.0093）μmol/L,（0.0359±0.0203）μmol/L,（0.0532±0.0199）μmol/L and（0.0319±0.0036）μmol/L,respectively.（2）The antigrowth effect of ganetespib in combination with triptolide in K562 and HL-60 cell is synergistic.（3）Ganetespib and triptolide downregulated Bcr-Abl,Akt and the phosporylation of Akt and increased the expression of apoptotic proteins of cleaved caspase-3,cleaved caspase-7,cleaved caspase-9 and cleaved PARP;Ganetespib increased the protein level of Hsp70 and downregulated the phosporylation of ERK,but triptolide decreased the protein level of Hsp70 and upregulated the phosporylation of ERK.（4）The combination of genetespib and triptolide shows significantly synergistic effect on cell proliferation and induce cell apoptosis by downregulating Bcr-Abl,Akt,Hsp70 and the phosporylation of Akt,increasing cleaved caspase-3,cleaved caspase-7,cleaved caspase-9 and cleaved PARP.Conclusion:（1）The combination of genetespib with triptolide synergistically induced cell growth inhibition and apoptosis in human leukemia cell lines in vitro.（2）Ganetespib is synergistic with triptolide,the mechanism of which may be based on downregulation of the genetespib-induced expression of Hsp70 by triptolide,inhibition of the proliferation of cells and activation of caspase apoptotic pathways. |
