Notch1 and PI3K/Akt signaling blockers DAPT and LY294002 coordinately inhibit metastasis of gastric cancer through mutual enhancement.

Blockade of either Notch1 or PI3K/Akt pathway inhibits metastasis of gastric cancer. However, whether blockade of both pathways coordinately exerts such an effect remains unknown. In this study, we aimed to investigate the effects of combined treatment with Notch1 signaling blocker DAPT and PI3K/Akt signal blocker LY294002 on metastasis of gastric cancer. Notch intracellular domain (NICD) and phosphorylated Akt (p-Akt) levels in gastric cancer tissues and their adjacent normal tissue samples and gastric cancer SGC7901 and AGS cells and normal GES-1 cells were determined using immunohistochemistry and Western blotting. The effects of combined DAPT and LY294002 on metastasis of gastric cancer were evaluated by examining migration and invasion potential of SGC7901 cells using wound healing and transwell assays, determining changes in the levels of epithelial-mesenchymal transition biomarkers and MMP-9, Notch1, HES1, and phosphorylation of Akt in gastric cancer SGC7901 cells and/or AGS cells in vitro using Western blotting, and metastasis of gastric cancer to lungs in BALB/c nude mice after treatment. NICD and p-Akt levels were significantly higher in gastric cancer tissues and SGC7901 and AGS cells than those in the normal control and GES-1 cells. Migration and invasion potential of SGC7901 cells, EMT biomarkers and MMP-9 in SGC7901 cells, and metastasis of gastric cancer to lungs in mice were coordinately inhibited by DAPT and LY294002. In addition, DAPT and LY294002 coordinately inhibited the levels of Notch1, HES1, and p-Akt in gastric cancer cells. DAPT and LY294002 coordinately inhibited metastasis of gastric cancer through mutual enhancement.