Coupling Kinesin Spindle Protein and Aurora B Inhibition with Apoptosis Induction Enhances Oral Cancer Cell Killing.

Simple Summary: Scientists are studying proteins like kinesin spindle protein and Aurora B, crucial for cell division and potential targets in cancer treatment. Drugs aimed at these proteins show promise in lab tests for killing cancer cells, but in clinical trials alone, they are not always effective, possibly due to varied cancer cell responses. To enhance their efficacy, researchers are exploring combinations with other cell-killing drugs. Our study focused on Navitoclax, an inducer of cancer cell death, tested alongside Ispinesib and Barasertib, targeting kinesin spindle protein and Aurora B, respectively. Together, these drugs induced significant cancer cell death, mainly through apoptosis. Moreover, imaging techniques revealing their combined effects suggest that combining these drugs could be a potent cancer treatment strategy, warranting further investigation in clinical trials. Many proteins regulating mitosis have emerged as targets for cancer therapy, including the kinesin spindle protein (KSP) and Aurora kinase B (AurB). KSP is crucial for proper spindle pole separation during mitosis, while AurB plays roles in chromosome segregation and cytokinesis. Agents targeting KSP and AurB selectively affect dividing cells and have shown significant activity in vitro. However, these drugs, despite advancing to clinical trials, often yield unsatisfactory outcomes as monotherapy, likely due to variable responses driven by cyclin B degradation and apoptosis signal accumulation networks. Accumulated data suggest that combining emerging antimitotics with various cytostatic drugs can enhance tumor-killing effects compared to monotherapy. Here, we investigated the impact of inhibiting anti-apoptotic signals with the BH3-mimetic Navitoclax in oral cancer cells treated with the selective KSP inhibitor, Ispinesib, or AurB inhibitor, Barasertib, aiming to potentiate cell death. The combination of BH3-mimetics with both KSP and AurB inhibitors synergistically induced substantial cell death, primarily through apoptosis. A mechanistic analysis underlying this synergistic activity, undertaken by live-cell imaging, is presented. Our data underscore the importance of combining BH3-mimetics with antimitotics in clinical trials to maximize their effectiveness. [ABSTRACT FROM AUTHOR]