OBJECTIVETo investigate the effect and possible mechanism of low concentration of triptolide (TPL) combined with homoharringtonine (HHT) on the proliferation and apoptosis of KG-1α cells.

METHODSCCK-8 method was used to detect the antiproliferating effects of different concentrations of TPL and HHT single-use and combined use on KG-1α cells, and the combined index (CI) was calculated. The colony formation ability was also determined by methylcellulose colony formation assay, cell surface molecules, apoptosis rate and cell cycle changes were detected by flow cytometry. Westerrn blot was used to detect the expression of Akt signaling pathway related proteins before and after low dose TPL combined with HHT using.

RESULTSHigh expression of CD34 and CD123 were on KG-1a cells, which being lack expression of CD38. TPL and HHT dose-dependently inhibited the proliferation of KG-1α cells. Compared with low dosage TPL and HHT single-use groups, the cell proliferation and colony formation efficiency were lower, and the cell apoptosis rate was higher in the combined group. CI values also indicated that low concentration TPL combined with HHT possessed highly synergistic effect. After the combination of the 2 drugs, the expressions of P-Akt, P-Akt, BCL-2, PARP and survivin protein were down-regulated and the cleavage of PARP protein was increased.

CONCLUSIONLow concentration of TPL combined with HHT can synergistically inhibit KG-1α cell proliferation and induce its apoptosis through the PI3K/Akt signaling pathway and downstream protein.