Dasatinib (BMS-354825) tyrosine kinase inhibitor suppresses invasion and induces cell cycle arrest and apoptosis of head and neck squamous cell carcinoma and non-small cell lung cancer cells

Purpose: Epithelial tumors, including non-small cell lung cancer (NSCLC) and head and neck squamous cell carcinoma (HNSCC), present clinical challenges. One potential target for systemic therapy is Src family nonreceptor tyrosine kinases, which are overexpressed in these tumors and induce pleiotropic effects, including increased proliferation, enhanced survival, stimulation of angiogenesis, and changes in motility. Dasatinib (BMS-354825), an ATP-competitive, small molecule tyrosine kinase inhibitor, suppresses the activity of these kinases at subnanomolar concentrations, Therefore, we tested the antitumor effects of this inhibitor in vitro to determine whether in vivo analyses were warranted. Experimental Design: The antitumor effects of dasatinib on HNSCC and NSCLC cells were evaluated using assays to measure cell cycle progression, apoptosis, migration, and invasion. Western blotting was used to monitor its effects on cell signaling. Results: Dasatinib inhibited migration and invasion in all cell lines and induced cell cycle arrest (blocking the G₁-S transition) and apoptosis in some lines. The effects on migration and invasion correlated with the inhibition of Src and downstream mediators of adhesion [e.g., focal adhesion kinase (FAK), p130, and paxillin], and the cell cycle effects and apoptosis correlated with the induction of p27 and the dephosphorytation of Rb. Dasatinib also induced morphologic changes that were consistent with an upstream role for Src in regulating focal adhesion complexes. Conclusions: This study showed that Src inhibition in HNSCC and NSCLC has antitumor effects in vitro. This suggests that dasatinib would have therapeutic activity against these tumors. Clinical studies in these tumor types are warranted.