Possible mechanisms of paclitaxel-induced apoptosis.
Paclitaxel, a naturally occurring antimicrotubule agent, has been demonstrated to possess significant cell-killing activity in a variety of tumor cells through induction of apoptosis. It is currently unclear whether this finding suggests a novel mechanism of action for paclitaxel against tumor cells or just represents an end product of the well-known action of paclitaxel on microtubules and cell cycle arrest. Morphologically, a sustained block of mitosis seems to be required for paclitaxel-induced apoptosis because most apoptotic events are observed to occur in cells showing a prior mitotic arrest. However, this morphological correlation alone does not prove that paclitaxel-induced apoptosis is indeed a secondary event resulting from mitotic arrest. Instead, several lines of evidence obtained from recent studies have suggested that apoptotic cell death induced by paclitaxel may occur via a signaling pathway independent of microtubules and G2/M arrest.
Fan
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Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston 29425, USA. fanw@musc.edu
D000470:Alkaloids / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis; D004347:Drug Interactions; D016195:G2 Phase / Q000187:drug effects; D005938:Glucocorticoids / Q000494:pharmacology; D006801:Humans; D008938:Mitosis / Q000187:drug effects; D017239:Paclitaxel / Q000494:pharmacology*; D043823:Taxoids; D014407:Tumor Cells, Cultured
D000470:Alkaloids; D000972:Antineoplastic Agents, Phytogenic; D005938:Glucocorticoids; D043823:Taxoids; C073950:baccatin III; D017239:Paclitaxel