Combined Inhibition of KIF11 and KIF15 as an Effective Therapeutic Strategy for Gastric Cancer

Background: Novel therapeutic strategies are urgently required to improve clinical outcomes of gastric cancer (GC). KIF15 cooperates with KIF11 to promote bipolar spindle assembly and formation, which is essential for proper sister chromatid segregation. Therefore, we speculated that the combined inhibition of KIF11 and KIF15 might be an effective strategy for GC treatment. Hence, to test this hypothesis, we aimed to evaluate the combined therapeutic effect of KIF15 inhibitor KIF15- IN-1 and KIF11 inhibitor ispinesib in GC. Methods: We validated the expression of KIF11 and KIF15 in GC tissues using immunohistochemistry and immunoblotting. Next, we determined the effects of KIF11 or KIF15 knockout on the proliferation of GC cell lines. Finally, we investigated the combined effects of the KIF11 and KIF15 inhibitors both in vitro and in vivo. Results: KIF11 and KIF15 were overexpressed in GC tissues than in the adjacent normal tissues. Knockout of either KIF11 or KIF15 inhibited the proliferative and clonogenic abilities of GC cells. We found that the KIF15 knockout significantly increased ispinesib sensitivity in GC cells, while its overexpression showed the opposite effect. Further, using KIF15-IN-1 and ispinesib together had a synergistic effect on the antitumor proliferation of GC both in vitro and in vivo. Conclusion: This study shows that the combination therapy of inhibiting KIF11 and KIF15 might be an effective therapeutic strategy against gastric cancer.