Toosendanin inhibits growth and induces apoptosis in colorectal cancer cells through suppression of AKT/GSK-3β/β-catenin pathway

AKT/GSK-3β/β-catenin signaling pathway plays an important role in the progression of colorectal cancer (CRC). Toosendanin (TSN) is a triterpenoid extracted from the bark or fruits of Melia toosendan Sieb et Zucc and possesses anti-tumour effects on various human cancer cells. However, its effect on CRC remains poorly understood. The present study investigated the effect of TSN on CRC SW480 cells and the AKT/GSK-3β/β-catenin signaling. Proliferation assay, flow cytometry and Hoechst 33342 nuclear staining demonstrated TSN dose-dependently inhibited cell viability and induced cell apoptosis as well as cell cycle arrest in S phase. Confocal laser scanning microscope showed β-catenin transferred to the outside of the nucleus in TSN-treated cells. Quantitative real-time PCR and western blot analysis found that TSN effectively modulated molecules related to apoptosis and AKT/GSK-3β/β-catenin signaling. Moreover, TSN administration significantly inhibited CRC growth in a mouse tumor xenograft model. In conclusion, our findings indicate that TSN inhibits growth and induces apoptosis in CRC cells through suppression of AKT/GSK-3β/β-catenin pathway, suggesting that TSN may have potential for use in CRC treatment.