Microtubules: a dynamic target in cancer therapy.

The tubulin/microtubule system is an important target for anticancer therapy. Two of the most clinically valuable groups of these agents are the vinca alkaloids and taxanes. In recent years, new tubulin-binding agents have been under preclinical or clinical development. One of these classes of agents, epothilones, has shown great promise in phase III clinical trials. What all these agents share in common, is that they bind to beta-tubulin and disrupt microtubule function during mitosis which in turn leads to mitotic arrest and cell death. In addition, these agents can inhibit angiogenesis. Not withstanding their effectiveness, drug resistance can pose a major clinical problem. This review provides an overview of the mechanisms mediating resistance to tubulin-binding agents related to the cellular target and discusses strategies to overcome this important clinical problem.