Per2 overexpression prevents the activation of the PI3K/AKT/mTOR pathway, and Per2 silencing contributes to activating the PI3K/AKT/mTOR pathway. The protein expression levels of PIK3CA, p-AKT and p-mTOR in Per2-OE cells were notably downregulated as detected by western blotting, and the levels of total AKT and total mTOR were not evidently changed. In Per2-RNAi cells, the PIK3CA, p-AKT and p-mTOR protein levels were obviously upregulated, and there were also no alterations in total AKT and total mTOR expression. All data represent three independent experiments. Data are presented as the mean ± SD (n ≥ 3). *P < 0.05; **P < 0.01; ***P <0.001; ****P < 0.0001.