Abstract: Objective　 To observe the effects of gallic acid on autophagy of human tongue squamous cell carcinoma SCC15 cell line and investigate their related molecular mechanism. Methods MTT assay was used to detect the effect of different concentrations of gallic acid on SCC15 cell proliferation. Monodansylcadaverine (MDC) staining was used to detect the effect of gallic acid on the autophagosome formation of SCC15 cells. Western blot was applied to detect the effect of gallic acid on the protein expression of LC3Ⅰ, LC3Ⅱ, Beclin1, and p-Akt and p-mTOR in PI3K/Akt/mTOR pathway. Results MTT assay showed that the inhibitory rate of SCC15 cells was significantly increased after 24 and 48 hours in the 90, 120, 150, 300, 600 μmol/L gallic acid group, with a dose-dependent relationship (P < 0.05). MDC staining results revealed that the scattered point fluorescence particles in the cytoplasm and around the nucleus of SCC15 in the 300 μmol/L gallic acid group were significantly increased. Western blot showed that gallic acid increased the ratio of LC3Ⅱ/LC3Ⅰ and the protein expression of Beclin1 after 48 hours (P＜0.05), while it significantly decreased the protein expressions of p-Akt and p-mTOR (P＜0.05). Conclusion Gallic acid under certain concentration can induce autophagy of SCC15, whose mechanism may be related to the down-regulation of the protein expression of p-Akt and p-mTOR through PI3K/Akt/mTOR pathway and the up-regulation of LC3 and Beclin1 protein expression.

Key words: Gallic acid, Oral Squamous Cell Carcinoma, Cell autophagy, PI3K/ Akt/mTOR pathway