Abstract: OBJECTIVE To investigate the anti-cancer efficacy of a novel AKT inhibitor Hu7691 against gastric cancer cells and its mechanism. METHODS Using human gastric cancer cells HGC27 and BGC823 as in vitro cell models, the SRB method was used to evaluate the in vitro proliferation inhibitory effects of Hu7691 at different concentrations on gastric cancer. The effect of Hu7691 on cell cycle was detected by flow cytometry. Western blotting was performed to determine the change of protein level caused by Hu7691 treatment. The in vivo anti-tumor efficacy was assessed in a human HGC27 gastric cancer xenograft model. RESULTS Hu7691 exhibited significant cytotoxicity in gastric cancer HGC27 and BGC823 cells and induced cell cycle arrest. Hu7691 treatment downregulated the protein expression of AKT pathway related proteins of p-PRAS40(T246), p-GSK3β, p-S6(S235/236), p-4EBP1(T37/46) and p-4EBP1(S65) in a concentration-dependent manner, while it upregulated the expression of p-AKT(S473) and p-AKT(S308), down-regulated the expression of cell cycle related protein Cyclin D1. The anti-cancer efficacy of Hu7691 was validated in the HGC27 xenograft model and had no significant effect on the body weight of the mice. CONCLUSION The novel AKT inhibitor Hu7691 exhibits potent in vitro and in vivo anti-caner efficacy on gastric cancer cells via inducing cell cycle arrest.