Abstract: Objective To investigate the expression of PTEN-Long in gastric cancer cells and its effect on the proliferation and apoptosis of gastric cancer cells (SGC-7901). Methods RT-qPCR and Western blotting were performed to detect the expression levels of PTEN-Long mRNA and protein in gastric cancer cells, and the cell line for further studies was selected. The recombinant lentiviral vector carrying the PTEN-Long gene was transfected into the SGC-7901 cells (the PTEN-Long group), cells in the NC group were transfected with the empty lentiviral vector, and cells in the control group were not transfected, and the transfection efficiency was detected. Cell proliferation was assayed by MTT method and Edu staining. Cell cycle and apoptosis were measured by flow cytometry. The expression levels of P27, cyclin D1 and PI3K/ AKT pathway related proteins were detected by Western blotting. Results The expression levels of PTEN-Long mRNA and protein in gastric cancer cells were greatly reduced (P < 0. 05). SGC-7901 cell line was selected for the subsequent experiments due to its lowest expression level of PTEN-Long among the detected gastric cancer cell lines. RT-qPCR and Western blotting confirmed that the lentivirus transfection was successful. Compared with the control group and the NC group, the cell proliferation in the PTEN-Long group was greatly reduced, the proportion of cells in the G0 / G1 phase was greatly increased, and the proportions of cells in the G2 / M and S phases were greatly decreased (P< 0. 05), the apoptosis rate was greatly increased. The expression level of P27 protein was greatly increased, and the protein expression levels of p-PI3K, p-AKT and cyclin D1 were greatly decreased in the PTEN-Long group (P < 0. 05). Conclusion PTEN-Long is down-regulated in gastric cancer cells, and the overexpression of PTEN-Long can inhibit the proliferation of gastric cancer cells and promote cell apoptosis by inhibiting the activation of PI3K/ AKT signaling pathway. 

Key words: PTEN-Long, gastric cancer cells, PI3K/ AKT signaling pathway, proliferation, apoptosis