Aurora kinase small molecule inhibitor destroys mitotic spindle, suppresses cell growth, and induces apoptosis in oral squamous cancer cells

Mitotic Aurora kinases are required for accurate chromosome segregation during cell. division. Ectopic expression of Aurora-A (Aur-A) kinase results in centrosome amplification, aberrant spindles, and consequent aneuploidy. In the present study, we showed that Aurora kinase inhibitory small molecule VX-680 inhibited histone H3 phosphorylation at Ser10, a known in vivo substrate residue of Aurora kinase, in oral squamous cell. carcinoma (OSCC) KB cells. In addition, monopolar spindle structures, typical. abnormalities induced by inhibition of Aur-A, were generated in VX-680-treated cells. Inhibition of Aurora kinase led to reduced KB cell. growth, as assessed by MTT assay. Western Not analysis revealed that VX-680 caused cleavage of two critical apoptotic associated proteins, PARP and caspase-3. In contrast, expression of cell survival factor Bcl-2 was reduced by VX-680 treatment in a dose-dependent manner. Subsequently, nuclear characteristic of DNA fragmentation, indicative of apoptotic cell. death, was clearly observed in these OSCC cells with Aurora kinase inhibitory VX-680. Taken together, we showed that Aurora kinase inhibitory VX-680 led to apoptotic cell death in OSCC cells, suggesting a novel therapeutic target in oral. cancer. (C) 2007 Elsevier Ltd. All rights reserved.