Paclitaxel

Paclitaxel is a novel antineoplastic agent, which was discovered in a screen of extracts of thousands of plants and natural products for antineoplastic activity by a National Y Institute program. Alought it functions as a mitotic inhibitor like vinca alkaloids, paclitaxel promotes the polymerization of tubulin instead of inducing the disassembly of microtubules, which inhibits the microtubules disassembly and promotes the formation of excessively stable, dysfunctional microtubules. Paclitaxel has exhibited antitumor activity against a broad spectrum of human Ys, including ovarian, breast, head and neck, and lung Y, in a large number of studies. (In Vitro) :Paclitaxel (20 nM; 48 hours) induces programmed cell death and exists a block at the G2/M phase of the cell cycle.Paclitaxel (20 nM; 48 hours) induces a consistent increase in the level of p53. (In Vivo) :Paclitaxel (1-20 mg/kg; i.p.; 1 time/2 days for five cycles) obviously induces liver metastases at the low-Paclitaxel group with little influence on primary tumor growth.