α-hederin induces autophagic cell death in colorectal cancer cells through reactive oxygen species dependent AMPK/mTOR signaling pathway activation.

α‑hederin, a monodesmosidic triterpenoid saponin, had previously demonstrated strong anticancer effects. In the current study, the pharmacological mechanism of autophagic cell death induced by α‑hederin was investigated in human colorectal cancer cells. First, through cell counting kit‑8 and colony formation assays, it was demonstrated that α‑hederin could inhibit the proliferation of HCT116 and HCT8 cell. Results of flow cytometry using fluorescein isothiocyanate Annexin V/propidium iodide and Hoechst 33258 staining indicated that α‑hederin could induce apoptosis. Western blotting demonstrated that α‑hederin could activate mitochondrial apoptosis signal pathway. Then, using light chain 3 lentiviral and electron microscope assay, it was demonstrated that α‑hederin could induce autophagy in colorectal cancer cells. In addition, immunohistochemistry results from in vivo experiments also demonstrated that α‑hederin could induce autophagy. AMP‑activated protein kinase (AMPK)/mechanistic target of rapamycin (mTOR) signaling was demonstrated to be activated by α‑hederin, which could be blocked by reactive oxygen species (ROS) inhibitor NAC. Furthermore, NAC could inhibit apoptosis and autophagy induced by α‑hederin. Finally, 3‑MA (autophagy inhibitor) reduced the inhibition of α‑hederin on cell activity, but it had no significant effect on apoptosis. In conclusion, α‑hederin triggered apoptosis through ROS‑activated mitochondrial signaling pathway and autophagic cell death through ROS dependent AMPK/mTOR signaling pathway activation in colorectal cancer cells.