Synthesis and Evaluation of Paclitaxel Immunoconjugate with Antitumor Activity In Vitro

Paclitaxel, also referred to as paclitaxel® is diterpenoid taxane derivative that was first identified in 1971 from Taxus brevifolia (1,2). This important discovery has spurred the isolation of many additional taxoids, in part with the hope of finding additional compounds with even better activity than paclitaxel itself. The structures of over 350 taxane diterpenoids have been reported (3). The antitumor property of paclitaxel is related to the promotion of tubulin assembly into microtubules (4–6). In the presence of paclitaxel, microtubules are resistant to depolymerization, thus interfering with the G2 and M phases of the cell cycle (7–9). Another mechanism proposed is the induction of apoptosis (10).