A biflavonoid-rich extract from Selaginella moellendorffii Hieron. induces apoptosis via STAT3 and Akt/NF-κB signalling pathways in laryngeal carcinoma

Selaginella moellendorffii Hieron. (SM), a perennial evergreen plant, has been used in the treatment of acute infectious hepatitis, thoracic and hypochondriac lumbar contusions, systemic oedema and thrombocytopaenia. However, the role of a biflavonoid-rich extract from SM (SM-BFRE) in anti-larynx cancer has rarely been reported. In this study, the in vitro and in vivo anti-laryngeal cancer activity and potential mechanisms of SM-BFRE were investigated. An off-line semipreparative liquid chromatography-nuclear magnetic resonance protocol was carried out to determine six biflavonoids from SM-BFRE. In vitro, MTT assay revealed that SM-BFRE inhibited the proliferation of laryngeal carcinoma cells. A wound healing assay indicated that SM-BFRE suppressed the migration of laryngeal cancer cells. Hoechst 33 258 and Annexin V-FITC/PI double staining assays were performed and verified that SM-BFRE induced apoptosis in laryngeal carcinoma cells. The Hep-2 bearing nude mouse model confirmed that SM-BFRE also exhibited anticancer effect in vivo. In addition, Western blot analysis demonstrated that SM-BFRE exerted its anti-laryngeal cancer effect by activating the mitochondrial apoptotic pathway and inhibiting STAT3 and Akt/NF-κB signalling pathways. All results suggested that SM-BFRE could be considered as a potential chemotherapeutic drug for laryngeal cancer.

Keywords: Akt/NF-κB; STAT3; Selaginella moellendorffii Hieron.; apoptosis; biflavonoid-rich extract; laryngeal carcinoma.