OBJECTIVETo evaluate biological effects of OCT4A gene on K562 cells and explore the molecular mechanism of K562 cell apoptosis.

METHODSTwo recombinant lentiviral vectors were constructed, which could stablely up- regulate and down- regulate OCT4A protein. Recombinant lentivirus was generated by co-transfection of three-plasmids and transfec-ted into K562 cells. The experiments were divided into 5 groups: normal, pLVX-OCT4A-ZsGreen1, pLVX vector control, PLB-OCT4A shRNA and non-specific shRNA groups. Western blot was applied to detect the expression of OCT4A protein, the cell counting kit-8 was applied to evaluate the effect of OCT4A on proliferation of K562 cells. The apoptosis and differentiation of K562 cells were detected by flow cytometry with AnnexinV/7-AAD double staining. The mRNA expressions of caspase-3,BIM,BCL-xL,BAX in K562 cells were determined by real time PCR.

RESULTSThe OCT4A fragment was amplified by reverse transcription polymerase chain reaction(RT-PCR), the 2 lentiviral vectors were successfully constructed. In comparson with those in the control group, the expression of OCT4A protein of pLVX-OCT4A-ZsGreen1 group was significantly increased, but decreased in PLB-OCT4A shRNA group. CCK-8 assay showed that the higher the content of OCT4A protein, the faster the cell proliferation. The apoptosis rate was (3.48±0.52)% of pLVX-OCT4A-ZsGreen1 group, which was lower than that of control group, while the apoptosis rate PLB-OCT4A shRNA group was (7.25±0.57)%, which was higher than that of control group (P<0.05), however, the K562 cells differentiation was not influenced(P>0.05). Compared with control group, the gene expression of Caspase-3,BIM and BAX was down-regulated(P>0.05), but a significant up-regulation of BCL-xL gene expression was observed(P<0.05).

CONCLUSIONTwo lentiviral vectors have been successfully constructed, which can stably up- and down- regulate the expression of OCT4A in K562 cells respectively. OCT4A can promote the K562 cell proliferation and inhibit the apoptosis, the mechanism may be related with up-regulation of BCL-xl expression.