Eupalinilide B as a novel anti-cancer agent that inhibits proliferation and epithelial–mesenchymal transition in laryngeal cancer cells

OBJECTIVE: To investigate the anti-cancer effects and potential mechanisms of eupalinilide B in laryngeal cancer cells. METHODS: Laryngeal cancer cell lines were selected to study the anti-tumor effects of eupalinilide B in vitro and in vivo. Lysine-specific demethylase 1 (LSD1) activity was assessed in vitro and dialysis experiments were performed to identify the anti-tumor target of the drug. RESULTS: Eupalinilide B concentration-dependently inhibited the proliferation of laryngeal cancer cells, exhibiting potent inhibitory activity against TU686 (IC(50) = 6.73 µM), TU212 (IC(50) = 1.03 µM), M4e (IC(50) = 3.12 µM), AMC-HN-8 (IC(50) = 2.13 µM), Hep-2 (IC(50) = 9.07 µM), and LCC cells (IC(50) = 4.20 µM). Subsequent target verification experiments demonstrated that eupalinilide B selectively and reversibly inhibited LSD1. Furthermore, eupalinilide B, as a natural product, suppressed epithelial–mesenchymal transition in TU212 cells. An in vivo experiment further indicated that eupalinilide B could significantly reduce the growth of tumors in TU212 xenograft mouse models. CONCLUSIONS: Eupalinilide B might be a novel LSD1 inhibitor for treating laryngeal cancer.