Celastrol Induces Apoptosis of Gastric Cancer Cells by miR-21 Inhibiting PI3K/Akt-NF-κB Signaling Pathway

Objective: Celastrol, a plant triterpene, has anticancer effects by increase of apoptosis. In the present study, the mechanism of celastrol on gastric cancer cell apoptosis was examined. Methods: The effect of celastrol on PI3K/Akt and the NF-κB signaling pathway was evaluated with Western blot and luciferase reporter assay. miR-21 expression was determined using real-time PCR. miR-21 inhibitor and miR-21 mimic were used to downregulate and upregulate miR-21 expression, respectively. Results: It was identified that celastrol was capable of inducing apoptosis of gastric cancer cells, which was mediated via inhibiting the activation of PI3K/Akt and NF-κB. A strong activator of Akt, IGF-1 restored NF-κB activity in cells treated with celastrol. Celastrol could also significantly suppress miR-21 expression. Furthermore, miR-21 inhibitor could decrease phospho-Akt expression and NF-κB activity. Notably, upregulation of miR-21 expression can increase PI3K/Akt and NF-κB activity and decrease apoptosis of gastric cancer cells treated with celastrol, which could be reversed by PI3K inhibitor. Conclusions: Our data revealed that the effect of celastrol on apoptosis was due to miR-21 inhibiting the PI3K/Akt-dependent NF-κB pathway.