LSD1 silencing inhibits the proliferation, migration, invasion, and epithelial-to-mesenchymal transition of hypopharyngeal cancer cells by inducing autophagy and pyroptosis

Hypopharyngeal cancer is a subtype of the head and neck malignancies. We aimed to explore the role of lysine-specific demethylase 1 (LSD1/KDM1A) in the progression of hypopharyngeal cancer and to identify the potential mechanisms. First, LSD1 expression in head and neck squamous cell carcinoma (HNSCC) tissues and the correlation between LSD1 and the stage of HNSC were analyzed by the University of ALabama at Birmingham CANcer data analysis Portal (UALCAN). Following LSD1 silencing, proliferation of pharyngeal cancer cell line FaDu cells was evaluated by cell counting kit-8 and colony formation assays. Wounding healing and transwell assays were used to measure the capacities of migration and invasion. In addition, expression of proteins related to epithelial-to-mesenchymal transition (EMT), autophagy, and pyroptosis was tested by Western blot analysis or immunofluorescence. After treatment with autophagy inhibitor 3-methyladenine (3-MA) or NLR family pyrin domain containing 3 (NLRP3) inhibitor MCC950, the malignant biological properties were measured again. High LSD1 expression was observed in HNSC tissues, which was correlated with stage. LSD1 knockdown significantly suppressed the proliferation, migration, invasion, and EMT of hypopharyngeal cancer cells. Moreover, autophagy and pyroptosis were induced by LSD1 depletion, observed by the enhanced fluorescence intensity of LC3, gasdermin-D (GSDMD)-N, and apoptosis-associated speck-like protein containing a CARD (ASC), accompanied by upregulated expression of LC3II/LC3I, Beclin-1, NLRP3, cleaved-caspase 1, ASC, interleukin (IL)-1 beta, and IL-18 and downregulated expression of p62. Importantly, 3-MA or MCC950 addition obviously reversed the inhibitory effects of LSD1 silencing on the proliferation, migration, invasion, and EMT of hypopharyngeal cancer cells. To sum up, LSD1 silencing could restrain the progression of hypopharyngeal cancer cells by inducing autophagy and pyroptosis.