Potent Hemithioindigo-Based Antimitotics Photocontrol the Microtubule Cytoskeleton in Cellulo

31 July 2019, Version 1
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

Hemithioindigo is a promising molecular photoswitch that has only recently been applied as a photoswitchable pharmacophore for control over bioactivity in cellulo. Uniquely, in contrast to other photoswitches that have been applied to biology, the pseudosymmetric hemithioindigo scaffold has allowed the creation of both dark-active and lit-active photopharmaceuticals for the same binding site by a priori design. However, the potency of previous hemithioindigo photopharmaceuticals has not been optimal for their translation to other biological models.

Inspired by the structure of tubulin-inhibiting indanones, we created hemithioindigo-based indanone-like tubulin-inhibitors (HITubs) and optimised their cellular potency as antimitotic photopharmaceuticals. These HITubs feature reliable and robust visible light photoswitching and high fatigue resistance. The use of the hemithioindigo scaffold also permitted us to employ a para-hydroxy hemistilbene motif – a structural feature which is denied to most azobenzenes due to the negligibly short lifetimes of their metastable Z isomers – which proved crucial to enhancing the potency and photoswitchability. The HITubs are ten times more potent than previously reported hemithioindigo photopharmaceutical antimitotics in a series of cell-free and cellular assays, and allowed robust photocontrol over tubulin polymerisation, microtubule network structure, cell cycle and cell survival.

We conclude that HITubs represent a powerful addition to the growing toolbox of photopharmaceutical reagents for microtubule cytoskeleton research. Additionally, as the hemithioindigo scaffold allows photoswitchable bioactivity for substituent patterns inaccessible to the majority of current photopharmaceuticals, wider adoption of the hemithioindigo scaffold may significantly expand the scope cellular and in vivo targets addressable by photopharmacology.

Keywords

antimitotic agents
Cytoskeletal proteins
hemithioindigo
photopharmacology
photoswitchable activity

Supplementary materials

Title
Description
Actions
Title
sailer2019b hitub supporting information v2.4
Description
Actions

Comments

Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.