OBJECTIVEThis study was aimed to investigate the effects of emodin combined with 3'-azido-3'-deoxythymidine (AZT) on proliferation and apoptosis of leukemia cell line KG-1a cells and its mechanism.

METHODSKG-1a cells were transfected with Egr-1 siRNA by electroporation and divided into blank control (KG-1a), nonspecific control (KG-1a/NC) and Egr-1 siRNA (KG-1a/siRNA) groups. Transfection efficiency was tested through fluorescence microscopy and flow cytometry and the transfection effect was detected by using qPCR. The cell proliferation rate was detected with MTT method. After the cells were treated with 10 µmol/L of emodin, 3200 or 1600 µmol/L of AZT and their combinations, the proliferation inhibition rates and the apoptosis rates of cells in 3 groups were detected with MTT method and FCM, respectively.

RESULTSThe transfection efficiency of Egr-1 siRNA was found to reach more than 59.21%; as compared with blank control(KG-1a) and nonspectic control(KG-1a/NC), the cell proliferation in Egr-1 siRNA group significantly reduced (P<0.01). The combination of emodin and AZT had considerable synergistic inhibitory effects on proliferation of normal KG-1a cells and nonspecific control(KG-1a NC) cells, but the synergistic effects disappeared after Egr-1 gene silencing.

CONCLUSIONThe effects of the combination of emodin and AZT on proliferation and apoptosis may be related with Egr-1.