Abstract: Objective: To detect the expression of X box binding protein 1 (XBP1) in human oral squamous cell carcinoma (OSCC) and to investigate the effect of inhibition the expression of XBP1 on proliferation and apoptosis of Tca8113. Methods: The expressions of XBP1 gene in the OSCC and paracancerous tissue were detected by RT-PC. NC-siRNA and XBP1-siRNA were transfected into Tca8113 cells, and the cells without any treatment were set the control group. The cell proliferation and apoptosis were detected after XBP1 gene transfection for 48h by CCK8 test and flow cytometry. The cleaved caspase3, β-catenin, and Cyclin D1 protein expression were detected by Western blot. Results: The mRNA expression of XBP1 gene in OSCC was significantly higher than that in paracancerous tissues (P<0.01). The expression of XBP1 protein and the cell viability were significantly decreased. Cell apoptosis were promoted. The protein expression of cleaved Caspase3 was increased, but the expressions of β-catenin and Cyclin D1 were decreased after XBP1-siRNA transfection (P<0.01). Conclusion: Silencing XBP1 gene expression by RNA interference can inhibit the proliferation of Tca8113 and induce apoptosis by inhibiting the Wnt/ β-catenin signaling pathway.

Key words: RNA interference , XBP1 gene, Oral squamous cell carcinoma, Proliferation, Apoptosis Wnt/β-catenin signaling pathway