Anticancer Agents Targeting Tubulin

Tubulin is one of the most useful and strategic molecular targets for anticancer drugs. The dynamic process of microtubule assembly and disassembly can be blocked by various agents that bind to distinct sites in the β-tubulin subunit. By interfering with microtubule function, these agents arrest cells in mitosis as well as interface, eventually leading to cell death, by both apoptosis and necrosis. So far, four binding domains have been identified a) the colchicine site close to the α/β interface, b) the area where the vinca alkaloids bind, c) the taxane-binding pocket and d) Laulimalide/Peloruside A Binding Site. This chapter compiles the patent literature up to 2015 and offers a detailed account of all the advances on anticancer agents targeting tubulin (lead molecules) along with in depth knowledge about the number of novel scaffolds, modified analogs and derivatives of the lead molecules. Colchicine binding site remains the most explored site indicated by the patent survey as majority of the patents revolve around phenstatins and combretastatins based molecules where the key structural feature for tubulin inhibition is an appropriate arrangement of the two aromatic rings at an appropriate distance and optimal dihedral angle maximizing interactions with tubulin. A brief account of promising microtubule destablizers/ stablizers in stages of clinical development and some strategies for the development of potent molecules overcoming the problem of drug resistance have also been discussed.

Keywords: Cancer, chalcones, colchicine, combretastatin A-4, cryptophycins, discodermolide, dolastatin, epothilones, halichondrin, hemiasterlins, 2-methoxye- -tradiol, microtubules, patents, phenstatin, podophyllotoxin, steganacin, taxol®, tubulin, tumor, vinca alkaloids.