A highly potent compound W-1-32 targeting XIAP protein inhibits proliferation and metastasis of esophageal squamous cell carcinoma.

Background: China bears the highest global burden of esophageal cancer, with esophageal squamous cell carcinoma representing the predominant histological subtype. The poor clinical outcome of ESCC is largely attributable to its aggressive invasiveness and early metastatic spread. Currently, effective first-line targeted therapies remain limited, underscoring the need to identify actionable molecular targets and develop novel targeted agents for ESCC. Methods: XIAP expression was examined by Western blot analysis. Cell proliferation was assessed using CCK-8 assays, while cell migration and invasion were evaluated by wound-healing and Transwell assays. The interaction between W-1-32 and XIAP was investigated using drug affinity responsive target stability and cellular thermal shift assays. Molecular docking and molecular dynamics simulations were employed to explore the binding mode of W-1-32 to XIAP. Results: A small-molecule compound, W-1-32, was identified as a modulator of XIAP. Computational analyses suggested a stable binding mode between W-1-32 and XIAP mediated by hydrogen bonding and noncovalent interactions, which was further supported by DARTS and CETSA assays. Treatment with W-1-32 reduced XIAP protein abundance in ESCC cells and was associated with decreased cell proliferation and migratory capacity. Notably, W-1-32 exhibited lower cytotoxicity toward normal esophageal epithelial cells compared with ESCC cells, indicating a degree of tumor selectivity Conclusion: Our results confirmed that W-1-32 significantly reduces ESCC cell proliferation and migration, which may be attributed to its binding to XIAP and the consequent reduction of XIAP protein levels. These findings identify W-1-32 as a XIAP-modulating compound with selective