Department of Biosciences, Graduate School of Science and Engineering, Soka University, 1-236 Tangi-cho, Hachioji, Tokyo 192-8577, Japan.
J Biochem. 2021 Oct 11;170(2):229-237. doi: 10.1093/jb/mvab035.
The mitotic kinesin Eg5 is a plus-end directed homotetrameric molecular motor essential for the formation of bipolar spindles during cell division. Kinesin Eg5 is overexpressed in cancer cells and hence considered as a target for cancer therapy; the inhibitors specific for Eg5 have been developed as anticancer drugs. In this study, we synthesized a novel functional photoresponsive inhibitor composed of spiropyran and azobenzene derivatives to control Eg5 function with multistage inhibitory activity accompanied by the formation of different isomerization states. The photochromic inhibitor spiropyran-sulfo-azobenzene (SPSAB) exhibited three isomerization states: spiro (SP)-trans, merocyanine (MC)-cis and MC-trans, upon exposure to visible light, ultraviolet and in the dark, respectively. SPSAB-induced reversible changes in the inhibitory activity of ATPase and motor activities correlating with photoisomerization among the three states. Among the three isomerization states of SPSAB, the SP-trans isomer showed potent inhibitory activity at an IC50 value of 30 µM in the basal ATPase assay. MC-trans and MC-cis exhibited less inhibitory activity at IC50 values of 38 and 86 µM, respectively. The results demonstrated that the novel photochromic inhibitor enabled precise control of Eg5 function at three different levels using light irradiation.
有丝分裂驱动蛋白 Eg5 是一种正极导向的四聚体分子马达，对于细胞分裂过程中形成两极纺锤体至关重要。在癌细胞中，Eg5 过表达，因此被认为是癌症治疗的靶点；针对 Eg5 的抑制剂已被开发为抗癌药物。在这项研究中，我们合成了一种新型的功能性光响应抑制剂，由螺吡喃和偶氮苯衍生物组成，以控制 Eg5 功能，具有多阶段抑制活性，并伴随着不同的异构化状态的形成。光致变色抑制剂螺吡喃-磺基-偶氮苯（SPSAB）在暴露于可见光、紫外光和黑暗中时，分别呈现出三种异构化状态：螺（SP）-反式、次甲基（MC）-顺式和 MC-反式。SPSAB 诱导的 ATP 酶抑制活性的可逆变化与三种状态之间的光致异构化相关。在 SPSAB 的三种异构化状态中，SP-反式异构体在基础 ATP 酶测定中表现出 30µM 的强抑制活性。MC-反式和 MC-顺式的抑制活性分别为 38µM 和 86µM。结果表明，新型光致变色抑制剂能够通过光照射在三个不同水平上精确控制 Eg5 功能。
