Novel photochromic inhibitor for mitotic kinesin Eg5 which forms multiple isomerization states

Abstract

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 a target for cancer therapy; the inhibitors specific for Eg5 have been developed as anti-cancer drugs. In this study, we synthesized a novel functional photoresponsive inhibitor composed of spiropyran and azobenzene derivatives to control Eg5 function with multi-stage 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 (VIS), ultraviolet (UV), and in the dark, respectively. SPSAB induced reversible changes in the inhibitory activity of ATPase and motor activities correlating with photo-isomerization 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 µM 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.

The Evaluation of DHPMs as Biotoxic Agents on Pathogen Bacterial Membranes

“…Monastrol as a specific compound is a protagonist of the DHPM class. Research has revealed that its action as an inhibitor on human kinesin Eg5 leads to apoptosis by mitotic spindle arrest [8][9][10][11]. Reported data show other possible targets for these molecules, such as centrin [12], calcium channels [13] and topoisomerase I [14].…”

Optical Control of Mitosis with a Photoswitchable Eg5 Inhibitor

“…The Tamaoki group introduced one of the first photoswitchable inhibitors of a motor protein for the mitotic kinesin CENP‐E, which was based on the small molecule GSK923295 [37, 38] . Recently, Maruta and colleagues introduced photoswitchable inhibitors that enabled reversible control of Eg5 in vitro [39–41] . However, they did not demonstrate activity in cells, possibly due to insufficient cell permeability and solubility of their compounds.…”

“…[37,38] Recently, Maruta and colleagues introduced photoswitchable inhibitors that enabled reversible control of Eg5 in vitro. [39][40][41] However, they did not demonstrate activity in cells, possibly due to insufficient cell permeability and solubility of their compounds. This led us to synthesize and evaluate azobenzenebased photoswitchable Eg5 inhibitors.…”

Photocontrol of GTPase Cycle and Multimerization of the Small G-Protein H-Ras using Photochromic Azobenzene Derivatives

“…These nucleotide-binding proteins might have evolved from a common nucleotidebinding ancestral protein, as they share a common catalytic core region, including the P-loop, Switch I, and Switch II, and molecular mechanisms utilizing a nucleotide hydrolysis cycle. Previously, we demonstrated that incorporating artificial regulatory nanodevices, such as photochromic molecules, into the kinesin functional site enables photoreversible regulation of ATPase activity [5][6][7] . Subsequently, we incorporated azobenzene derivatives into the functional sites of the motor domain and succeeded in photocontrolling GTPase activity 8 .…”