The Effect Of Survivin Geng Expression On The Lymphocyte Proliferation And Function In K562 Cells

Objective: To study the effect of survivin gene expression on the lymphocyte's proliferation and function in experimental leukemia cells in vitro by enhancing and decreasing the expression of survivin gene in K562 cells which may be used for further research in mechanism of genesis and development of tumor and establish important experimental basis for immune-gene therapy of tumor.Methods:①The vector pEGFP-C1 with survivin gene was transfected into K562 cells with liposome-mediated method to enhance the expression of survivin gene and then the K562 cells were sieved by G418(K562/survivin+ cells).②The plasmid pTZU6+1 containing short hairpin RNA of survivin was transfected into K562 cells with liposome-mediated method to decrease the expression of survivin gene(K562/survivin- cells).③The survivin mRNA levels in the three kinds of cells(K562/survivin+,K562 and K562/survivin-) were detected by semi-quantitative RT-PCR.④Peripheral blood mononuclear cells(PBMCs) were separated by Ficoll-hypaque density gradient centrifugation from blood of healthy adults.⑤PBMC were co-cultured with tumor cells(mixed lymphocyte-tumor cell culture, MLTC). Experimental tumor cells were divided into 3 groups: K562/survivin+ group , K562 group and K562/survivin- group. Lymphocyte Proliferation in the supernatant was evaluated by MTT assay. Nature killer activity was detected by flow cytometry and IFN-γlevel was detected by ELISA assay.Result:①Enhanced and decreased survivin gene were stably expressed in K562 cells.②Semi-quantitative RT-PCR assay revealed that survivin mRNA level in K562/survivin+ cells was much higher than that in the K562 cells and survivin mRNA level in K562/survivin- cells was much lower than that in the K562 cells. The mRNA levels ofβ-actin in the three groups were not different.③Proliferation index in K562/survivin+ group was much smaller than that in the K562 group(P<0.05). Proliferation index in K562/survivin- group was much higher than that in K562 group(P>0.05).④NK activity in K562/survivin+ group was much smaller than that in the K562 group(P<0.05). NK activity in K562/survivin- group was much higher than that in K562 group (P<0.05).⑤IFN-γsecretion in the MLTC with K562/survivin+ group was lower than that in K562 group (P<0.05). IFN-γsecretion in the MLTC with K562/survivin- group was higher than that in K562 group (P<0.05).Conclusions:①The high expression of survivin gene may inhibit lymphocyte proliferation.②The high expression of survivin gene may inhibit nature killer activity; the low expression of survivin gene may up-regulated nature killer activity.③The high expression of survivin gene may inhibit the secretion of IFN-γ; the low expression of survivin gene may up-regulated the secretion of IFN-γ.④Survivin gene may inhibit the systemic anti-neoplastic immunity to help tumor cells escape from the immune control.