OBJECTIVE

To investigate the effects of kuwanon G (KG) on proliferation, apoptosis, migration and invasion of gastric cancer cells and the molecular mechanisms.

METHODS

The effects of KG on proliferation and growth of gastric cancer cells were assessed with CCK-8 assay and cell clone formation assay, by observing tumor formation on the back of nude mice and using immunohistochemical analysis of Ki-67. The effect of KG on cell apoptosis was analyzed using Annexin V-FITC/PI apoptosis detection kit, Western blotting and TUNEL staining. The effects of KG on cell migration and invasion were detected using Transwell migration and invasion assay and Western blotting for matrix metalloproteinase (MMP). The role of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway in KG-mediated regulation of gastric cancer cell proliferation, migration, and invasion was verified by Western blotting and rescue assay.

RESULTS

KG significantly inhibited proliferation and reduced clone formation ability of gastric cancer cells in a concentration-dependent manner ( < 0.05). KG treatment also increased apoptosis, enhanced the expressions of cleaved caspase-3 and Bax, down-regulated Bcl-2, lowered migration and invasion capacities and inhibited the expression of MMP2 and MMP9 in gastric cancer cells ( < 0.05). Mechanistic validation showed that KG inhibited the activation of the PI3K/AKT/mTOR pathway, and IGF-1, an activator of the PI3K/AKT/mTOR pathway, reversed the effects of KG on proliferation, migration and invasion of gastric cancer cells ( < 0.05).

CONCLUSION

KG inhibits proliferation, migration and invasion and promotes apoptosis of gastric cancer cells at least in part by inhibiting the activation of the PI3K/AKT/mTOR pathway.