Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109.
Department of Chemistry, Pennsylvania State University, University Park, PA 16802.
Mol Biol Cell. 2022 Dec 1;33(14):ar132. doi: 10.1091/mbc.E22-06-0225. Epub 2022 Oct 6.
Mitosis is the cellular process that ensures accurate segregation of the cell's genetic material into two daughter cells. Mitosis is often deregulated in cancer; thus drugs that target mitosis-specific proteins represent attractive targets for anticancer therapy. Numerous inhibitors have been developed against kinesin-5 Eg5, a kinesin essential for bipolar spindle assembly. Unfortunately, Eg5 inhibitors (K5Is) have been largely ineffective in the clinic, possibly due to the activity of a second kinesin, KIF15, that can suppress the cytotoxic effect of K5Is by driving spindle assembly through an Eg5-independent pathway. We hypothesized that pairing of K5Is with small molecule inhibitors of KIF15 will be more cytotoxic than either inhibitor alone. Here we present the results of a high-throughput screen from which we identified two inhibitors that inhibit the motor activity of KIF15 both in vitro and in cells. These inhibitors selectively inhibit KIF15 over other molecular motors and differentially affect the ability of KIF15 to bind microtubules. Finally, we find that chemical inhibition of KIF15 reduces the ability of cells to acquire resistance to K5Is, highlighting the centrality of KIF15 to K5I resistance and the value of these inhibitors as tools with which to study KIF15 in a physiological context.
有丝分裂是一种细胞过程，可确保细胞的遗传物质准确地分裂成两个子细胞。癌症中经常会出现有丝分裂失控的情况；因此，针对有丝分裂特异性蛋白的药物是癌症治疗的有吸引力的靶点。已经开发出了针对驱动蛋白-5（Eg5）的许多抑制剂，Eg5 是一种对于双极纺锤体组装至关重要的驱动蛋白。不幸的是，Eg5 抑制剂（K5Is）在临床上基本上没有效果，这可能是由于第二种驱动蛋白 KIF15 的活性所致，KIF15 可以通过 Eg5 独立途径驱动纺锤体组装来抑制 K5Is 的细胞毒性作用。我们假设将 K5Is 与 KIF15 的小分子抑制剂联合使用将比单独使用任何一种抑制剂更具细胞毒性。在这里，我们展示了高通量筛选的结果，从中我们鉴定出两种抑制剂，它们可以在体外和细胞内抑制 KIF15 的运动活性。这些抑制剂可以选择性地抑制 KIF15 而不是其他分子马达，并对 KIF15 结合微管的能力产生不同的影响。最后，我们发现化学抑制 KIF15 降低了细胞获得对 K5Is 耐药性的能力，这突出了 KIF15 在 K5I 耐药性中的核心地位，以及这些抑制剂作为在生理环境中研究 KIF15 的工具的价值。
