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

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 RuII and OsII complexes and investigated their microtubule-targeting properties in comparison with paclitaxel and colchicine. Compounds were fully characterized by spectroscopic techniques (1H 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 1H and 13C 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 RuII 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.