Preliminary Study On The Effect Of RetroNectin On CIK Cells' Proliferation, Phenotype And Anti-tumor Activity

Objects: To study the effect of RetroNectin on the proliferation, phenotype changeand anti-tumor activity of CIK cells and investigate the possible mechanism. Method:Monouclear cells were collected frome person's peripheral blood, and every samplewas divided into two groups. The control group was induced to propagate by usingIFN-γ, IL-2, IL-1αand CD3 mAb, and for the experiment group, RetroNectin wasadded as another inducement. The number of CIK cells was counted by living cellcounting method in different cultural time to observe the growth of the CIK cells, andthe phenotype change of the CIK cells was detected by flow cytometry. Meanwhile,cytotoxicity of CIK cells to tumor cell lines K562 and PC-3 was also measured byusing LDH-release assay. Apoptotic rates of CIK cells cultured with or withoutRetroNectin were evaluated by AnnexinV/PI staining. The effect of RetroNectin oncell cycle was measured by flow cytometry. Result: After stimulated by cytokinesand anti-CD3 antibody, CIK cells can proliferate significantly. The number of CIKwas increased to 96.13±5.03 fold induced by IFN-γ,, IL-2, IL-1α, CD3 mAb and330.46±7.96 fold induced by another RetroNectin, respectively. The CD3~+CD8~+ andCD3~+CD56~+ cells were increased significantly compared with those of PBMC withthe progression of the cultural time and the CD3~+CD4~+ cells were decreased with theprogression of cultural time. But there was not significant difference between thecontrol and experiment group. The CD25~+ cells stimulated by RetroNectin wereincreased significantly compared with those CIK cells induced without RetroNectin(p＜0.05). The cytotoxicity of CIK cells to tumor cell lines was increased withprogression of the cultural time. However, the cytotoxicity of CIK cells to K562 andPC-3 was similar between the two groups (p＞0.05). The'apoptotic rates of CIK cellscultured with or without RetroNectin are not significantly different (p＞0.05). Thecells arrested in the S stage in the RetroNectin induced group were higher than the control group (p＜0.05). Conclusion: 1. CIK cells have strong proliferative abilityand higher cytotoxicity to tumor cells in vitro. 2. RetroNectin can effect CIK cells'proliferation but has no effect on CIK cells' phenotype change and cytotoxicity. 3.The possible mechanism of CIK cells' proliferation promoted by RetroNectin may beas follows: (1) promote the adherence and strengthen the signal conduction betweencells; (2) induce the T cell to be activated; (3) resist cell apoptosis; (4) promote thecell to develop from G1 to S stage.