Inhibition of Microtubule Dynamics in Cancer Cells by Indole-Modified Latonduine Derivatives and Their Metal Complexes

[Image: see text] Indolo[2,3-d]benzazepines (indololatonduines) are rarely discussed in the literature. In this project, we prepared a series of novel indololatonduine derivatives and their Ru(II) and Os(II) complexes and investigated their microtubule-targeting properties in comparison with paclitaxel and colchicine. Compounds were fully characterized by spectroscopic techniques ((1)H NMR and UV–vis), ESI mass-spectrometry, and X-ray crystallography, and their purity was confirmed by elemental analysis. The stabilities of the compounds in DMSO and water were confirmed by (1)H and (13)C NMR and UV–vis spectroscopy. Novel indololatonduines demonstrated anticancer activity in vitro in a low micromolar concentration range, while their coordination to metal centers resulted in a decrease of cytotoxicity. The preliminary in vivo activity of the Ru(II) complex was investigated. Fluorescence staining and in vitro tubulin polymerization assays revealed the prepared compounds to have excellent microtubule-destabilizing activities, even more potent than the well-known microtubule-destabilizing agent colchicine.