Inhibition of autophagy enhances the anticancer effect of Schisandrin B on head and neck squamous cell carcinoma

Abstract Head and neck squamous cell carcinoma (HNSCC) is among the most common malignant tumors worldwide and has a poor prognosis. Autophagy regulation has been proposed as a possible treatment option for HNSCC. Schisandrin B (Sch B) exerts anticancer effects by regulating apoptosis and autophagy, but the anticancer effect of Sch B in HNSCC remains unclear. This study aimed to investigate the effects of Sch B on human Cal27 HNSCC cells and to further reveal its potential regulatory mechanisms. The anticancer effect of Sch B was evaluated in vitro by flow cytometry, clonogenic assays, and Western blot analysis. The regulatory mechanism of Sch B‐induced apoptosis and autophagy was further explored by polymerase chain reaction, luciferase assay, and reactive oxygen species (ROS) detection. The results showed that Sch B significantly induced apoptosis and autophagy in Cal27 cells and that inhibition of autophagy enhanced the apoptotic effect of Sch B on Cal27 cells. Additionally, Sch B‐activated autophagy in Cal27 cells was dependent on the nuclear factor‐kappa B (NF‐κB) pathway, and ROS acted as a regulator of the NF‐B pathway. N‐acetylcysteine, a scavenger of ROS, inhibited Sch B‐dependent autophagy via the NF‐κB pathway. Based on the results, Sch B is a potential therapeutic agent for HNSCC and activates the NF‐κB pathway by increasing ROS production, which subsequently promotes autophagy in HNSCC cells. Therefore, the strategy of enhancing the anticancer effect of Sch B by inhibiting autophagy deserves further attention.