Skimmianine as a novel therapeutic agent suppresses proliferation and migration of human esophageal squamous cell carcinoma via blocking the activation of ERK1/2

Esophageal squamous cell carcinoma (ESCC), one of the main histopathological subtypes of esophageal cancer (EC), is characterized by high morbidity and mortality. Clinical treatment for ESCC lacks specific molecular targets and effective therapeutic drugs. Skimmianine (SK), one of the natural fluroquinolone alkaloids, is widely present in Rutaceae family plants. Here, we mainly used CCK-8 assay, clone formation, flow cytometry analysis, wound-healing assay, Transwell assay, western blot, quantitative real-time PCR (qRT-PCR), molecular docking analysis, tumor xenograft assay, and immunohistochemistry (IHC) staining to investigate the potential anti-tumor effect of SK on ESCC. We demonstrated that SK inhibited the proliferation of TE-1 and Eca109 cells via inducing the G0/G1 phase cell cycle arrest, prevented the migration and invasion of tumor cells via regulating epithelial-mesenchymal transition (EMT) in vitro. In addition, SK obviously suppressed the growth of xenografted Eca109 tumors in nude mice. The anti-tumor mechanism of SK could be blocking the activation of extracellular signal-regulated kinases 1/2 (ERK1/2) in the mitogen-activated protein kinase (MAPK)/ERK signaling pathway. Our basic research suggests that SK can be a potential therapeutic agent for ESCC.