Abstract: Objective To investigate the effect of cinnamic acid on the proliferation of tongue squamous cell carcinoma cell line Tca8113. Methods After treated with cinnamie acid，the morphological changes of Tca8113 were observed under inverted microscope. The proliferation inhibition of Tca8113 cell was detected by MTT method. The cell cycle of Tca8113 was analyzed by flow cytometry. The protein levels of KLF6,Bcl-2,p53,cyclin D1,c-Jun and PTEN were measured by the method of immunohistochemistry. Results It was showed that the proliferation of Tca8113 cells can be inhibited significantly by cinnnamic acid in vitro(p<0.05) ,and the inhibition is time and dose dependent； Typical feature of induced differentiation of Tca8113 cells was observed. After treated with cinnamic acid,the cell number in G1 and G2 phase was decreased significantly while the number in S phase was increased significantly.Tca8113 cells were significantly arrested in S phase (p<0.05) . The protein levels of KLF6 and p53 were increased(p<0.05) whereas the protein levels of Bcl-2, cyclin D1 and c-Jun decreased significantly(p<0.05). Conclusion Cinnamic acid inhibits the proliferation of Tca8113 cell by arresting the cell cycle in S phase,and then may induce TCA 8113 cell to apoptosis finally.

Key words: Tca8113, proliferation inhibition, cinnnamic acid, KLF6