Tubulin assembly inhibitor colchicines

Halichondrin B (7), a highly cytotoxic metabolite isolated from the Japanese sponge H. okadai is a tubulin assembly inhibitor,which binds to the colchicine domain. The macrocyclic portion seems to be essential for the activityEribulin (E7389 146) is a drug candidate designed on the basis of the macrocyclic portion of halichondrin B and is now under phase II/III trials for breast cancer conducted by Eisei Co. Ltd., Tokyo. ... 

Vinca alkaloids (vincristine, vinblastine, vinorelbine) are derived from the periwinkle plant (Vinca rosea). These agents work by binding to tubulin at a site different than colchicine or paclitaxel. They block polymerization, which prevents the formation of the mitotic spindle, and are used as antineoplastic agents. Taxanes produce a stabilization of microtubules similar to colchicine, but by a different mechanism, and also halt cells in metaphase. Paclitaxel (taxol) is the taxane used clinically. It is derived from the bark of the pacific yew. Taxol disrupts several microtubule-based functions as completely as inhibitors of polymerization, emphasizing the importance of assembly/disassembly balance in microtubule function. Recently, it has been found that paclitaxel also binds to and inhibits the function of a protein called bcl-2, an inhibitor of one or more pathways involved in mediating apoptosis. PaclitaxeTs interference with this function promotes apoptosis in addition to its microtubule-related inhibition of cell division. 

---