Data collection and refinement statistics.

<div><p>Microtubule-targeting agents are an important class of anti-cancer drugs; their full potential is however not realized because of significant myelotoxicity and neurotoxicity. We here report 3-nitropyridine analogues as a novel group of microtubule-targeting agents with potent anti-cancer effects against a broad range of cancer types. We show that these 3-nitropyridines induce cell cycle arrest in the G2-M phase and inhibit tubulin polymerization by interacting with tubulin. Determination of the tubulin–4AZA2996 structure by X-ray crystallography demonstrated that this class of compounds binds to the colchicine-site of tubulin. Furthermore, the anti-cancer effect was demonstrated both <i>in vitro</i> and <i>in vivo</i> in a murine heterotopic xenograft model of colon cancer. When administered intravenously, 4AZA2891 effectively inhibited cancer growth. Whereas 3-nitropyridine compounds do not induce myelotoxicity at pharmacological doses, the neurotoxicity associated with microtubule-targeting agents is still present.</p></div>