Mitosis antimitotic agents

Antimitotic drugs that target microtubules (MT) or its constituent protein tubulin are one of the most successful classes of anticancer agents discovered so far. MT are long, filamentous, tube-shaped protein polymers that are essential in all eukaryotic cells. Antimitotic agents are compounds that arrest cells in mitosis, which results in the slowing or blocking of mitosis and induction of apoptotic cell death. 

The Cryptophycins are a unique family of 16-membered macrolide antimitotic agents originally identified in blue-green algae (cyanobacteria) belonging to Nostocaceae (for review see [74]). The parent compounds of the series, Cryptophycin-1 or Cryptophycin-A (26) were found to block cells at mitosis in the low picomolar concentration range [75],... 

The antimitotic mechanism of taxol differs from the antimicrotubule agents such as colchicine and the vinca alkaloids discussed earlier. Rather than causing disassembly of the microtubules, taxol actually enhances tubulin polymerization. This upsets the normal dynamic equilibrium between soluble tubules, which are dimers, and the microtubule polymers. The stabilization of the latter inhibits mitosis in the latter part of Phase G2 and M. Although sharing much of the toxicology of many of the anticancer drugs, taxol promises to be an important addition to the cancer armamentarium. 

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