Taxol

Taxol, an antineoplastic and antimicrotubule agent, posses mechanisms of cytotoxic action and has a broad antineoplastic spectrum compared to the vinca alkaloids. Studies have shown that Taxol is an inhibitor of neurite outgrowth and initiation by destroying normal control of microtuble assemly in growing neurites and removing tubulin from the cytoplasm. At lower concentrations Taxol displays the capacity to slightly enhance the mechanisms of microtubule assembly in neurons, and in turn changes the morphogenetic properties of growing neurites. The mechanism for microtuble formation occurs by binding of Taxol to the N-terminal region of β-tubulin. These new microtubules are highly stable and resist depolymerization therefore preventing normal cell division and arresting cell cycle at the G₂/M phase. It has been reported that Taxol also causes apoptotic cell death, internucleosomal DNA fragmentation, and inhibition of protein isoprenylation. Taxol is a potential activator of PKA and Raf-1.