Objective   To explore the effect of the Epstein-Barr virus (EBV) BZLF1 gene on the biological behavior of EBV-negative gastric cancer cells and the underlying molecular mechanism.

  Methods   Lentiviral overexpressing BZLF1 was used to infect AGS and HGC27 gastric cancer cell lines. And the cell proliferation, apoptosis and migration invasive ability, and expression changes of cell signaling pathway were detected by CCK8 assay, apoptosis detection, migration and invasion assay, as well as western blot. HGC27 cells overexpressing BZLF1 were injected into the dorsal of NOD/SCID mice to construct xenografts, and the effect of BZLF1 on tumor growth was observed.

  Results   The expression of BZLF1 protein was significantly up-regulated in AGS-BZLF1 and HGC27-BZLF1 infected by over-expressing BZLF1 lentivirus. The cell proliferation in vitro and the tumorigenic ability in mice were significantly increased (P < 0.05). Apoptosis was inhibited by BZLF1 protein, and the apoptotic rate of AGS-BZLF1 and HGC27-BZLF1 was (2.40±0.14)% and (3.90± 0.14)%, which was significantly lower than (5.75±0.35)% and (9.70 ± 0.42)% of AGS and HGC cells (P < 0.05); however, there was no significant change in cell migration and invasion ability. In-depth molecular mechanism studies found that PI3K/AKT signaling pathway was significantly activated with enhanced pAKT and pS6 expression. After blocking the PI3K/AKT signaling pathway with BEZ235 inhibitor, the growth of HGC27-BZLF1 and AGS-BZLF1 cells was inhibited.

  Conclusions   EBV BZLF1 may promote the growth of gastric cancer cells by activating the PI3K/AKT signaling pathway and targeting PI3K/AKT pathway inhibitors, and serve as a promising treatment option for EBV-associated gastric carcinoma.