B7-H1 Expression And Its Contribution To The Regulation Of Biological Function In Human Esophageal Cancer Cell Line

Objective To study the impact that down-regulating the negative costimulation molecule B7-H1 on biological behavior in esophageal cancer cell line Eca-109.Methods Down-regulation of B7-H1 was performed by RNAi method in the human esophageal cancer cell line Eca-109,The expression level of B7-H1 was confirmed by flow cytometry and Western blot.The cell counting kit-8 assay,scrape assay,Transwell assay and nude mice tumorigenesis experiment were conducted to investigate the effect of B7-H1 on biological behavior of esophageal cancer cells.Results We successfully constructed stable reduced expression of B7-H1 in human esophageal cancer cell line by using RNAi named Eca109-B7-H1-siRNA and the control group Eca109-NC.The CCK-8 cell proliferation experiment showed that on day6,day7and day8,the proliferation rate of Eca109-B7-H1-siRNA group(0.61±0.03?0.78±0.04?0.89±0.04)was significantly lower than the control group(0.80±0.01?1.00±0.04?1.07±0.09;P<0.001),there is statistic significance betweeen Eca109-NC group and Eca-109 group(P>0.05).The scrape assay results showed that the cell migration ability of Eca109-B7-H1-siRNA group(126±22.63?m)was significantly lower than the control group(339±22.11?m)after scratched 24h(P<0.05),there is no singnificant difference betweeen Eca109-NC group and Eca-109 group(P>0.05).Transwell invasion assay results showed that at 24h after the cells seeded,the invasive cell number of Eca109-B7-H1-siRNA group(20.6±4.61)was relatively lower than the control group(60.4±12.50,P<0.01).The results showed that the tumor size of Eca109-B7-H1-siRNA cells(0.114±0.064)cm~3 was obviously smaller than that of Eca109-NC cells(0.651±0.107)cm~3 after 11 days of subcutaneous tumor growth in nude mice(P<0.001).The expression of B7-H1 was up-regulated in cell lines Eca109-B7-H1-OE and Eca109-B7-H1-OE?(cells over-expressing cytoplasmic truncated B7-H1).Cell proliferation experiment showed that the relative proliferation ability of Eca109-B7-H1-OE was significantly higher than that of WT cells(0.926±0.026 vs0.846±0.036,P<0.05),and the proliferation of Eca109-B7-H1-OE?and WT cells was not significantly different.Conclusion Down-regulation of B7-H1 in esophageal cancer cell line Eca-109 could significantly inhibit the cell proliferation,migration,invasion and tumorigenicity,suggesting that abnormal expression of B7-H1 in esophageal carcinoma cells could be involved in the regulation of tumor biological behavior and contribute to the tumor progression.There was no significant difference in the cell proliferation of Eca109-B7-H1-OE?,which indcated that the intracellular signaling of B7-H1 plays an important role in cell biology function,and provided a cell model for the B7-H1 signaling study.