Raddeanin A Induces Apoptosis and Cycle Arrest in Human HCT116 Cells through PI3K/AKT Pathway Regulation In Vitro and In Vivo

This study aimed to investigate the in vitro and in vivo effects of Raddeanin A on apoptosis and the cell cycle in the human colorectal cell line, HCT116, and to explore the possible underlying mechanisms of action. We found the growth inhibition rate gradually increased as the drug concentration increased via the 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assay, which indicated that Raddeanin A significantly inhibited the growth of HCT116 cells. Flow cytometry (FCM) showed that Raddeanin A concentration-dependently induced apoptosis in HCT116 cells. In addition, the percentage of cells in the G(0)/G(1) phase was noticeably increased, which indicated that Raddeanin A blocked cell cycle progression in HCT116 cells and caused arrest in the G(0)/G(1) phase. Moreover, the expression of proteins involved in the PI3K/AKT signaling pathway (e.g., p-PI3K and p-AKT) was decreased. The results showed that in vivo revealed that Raddeanin A significantly inhibited tumor growth in an HCT116-xenografted mouse model; apoptotic cells were also detected in the tumor tissue. The expression of the tissue proteins cyclinD1, cyclinE, p-PI3K, and p-AKT was decreased. The above results show that the Raddeanin A exerted a strong antitumor effect in the human colorectal cell line HCT116 both in vitro and in vivo. This effect may be caused by the induction of apoptosis and cycle arrest achieved through PI3K/AKT signaling pathway regulation.