Abstract: Objective: To investigate the effects and related mechanism of β-sitosterol on oral squamous cell carcinoma cells SSC9. Methods: SCC9 cells were treated by various dose of β-sitosterol, and the cell apoptosis was monitored. The intracellular ROS were analyzed and the mRNA and protein level of NADPH oxidase gp91^phox were detected. Knock down of gp91^phox in SCC9 was performed to confirm the effects of β-sitosterol on SCC9 cells. Results: Compared with the control group, β-sitosterol induced cell apoptosis in a dose dependent manner (P<0.01). β-sitosterol elevated the intracellular ROS level and mRNA and protein expression of gp91^phox in SCC9 cells. Inhibition of gp91^phox blocked the effect of β-sitosterol on SCC9 cells. Conclusion: NADPH oxidase gp91^phox had an important role in mediating the β-sitosterol-induced apoptotic process in SCC9 cells, which might be a target of OSCC treatment.

Key words: Oral squamous cell carcinoma, β-sitosterol, Apoptosis, ROS, Gp91^phox