Catalpol inhibits migration and induces apoptosis in gastric cancer cells and in athymic nude mice

Gastric cancer is one of the leading factors, causing tumor-associated death worldwide. However, due to the limited therapeutic strategies in inhibition of gastric cancer, further studies are still required to develop effective treatments. In the present study, we attempted to explore the effects of catalpol, extracted from a traditional Chinese herb Rehmannia glutinosa, on gastric cancer progression in cells and in xenograft nude mice. The results indicated that catalpol dose-dependently reduced the proliferation of cancer cells. The migrated cells were also decreased with catalpol treatment, as evidenced by the down-regulated expressions of matrix metalloproteinase-2 (MMP-2), alpha-smooth muscle actin (α-SMA), Ras homolog gene family, member A (RhoA), Rho kinase 1 (ROCK1) and N-cadherin. Further, catalpol induced apoptosis in gastric cancer cells. Apoptosis-related markers including cleaved Caspase-3 and PARP were highly expressed in catalpol-treated cells. However, the cells with pre-treatment of caspases inhibitor reversed catalpol-induced apoptosis. Further, catalpol also enhanced reactive oxygen species (ROS) generation in gastric cancer cells, which was eliminated by N-acetylcystein (NAC) pre-incubation, an important ROS scavenger. Of note, catalpol potentiated the anti-cancer effects of cisplatin (DDP) in suppressing gastric cancer cells. In vivo, catalpol prevented the tumor growth in xenograft nude mice, while no significant difference was observed in body weight. The immunohistochemical analysis showed that catalpol increased the number of terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL)-positive cells, whereas decreased the number of KI-67-positive cells. Together, the results above indicated that catalpol has a potential value in treating gastric cancer.