title: Paclitaxel induces apoptosis via caspase-3 activation in human osteogenic sarcoma cells (U-2 OS).
abstract: Paclitaxel has been found to exhibit cytotoxic and antitumor activity. There is little information regarding the mechanisms of apoptotic-inducing effect of paclitaxel on human osteogenic sarcoma U-2 OS cells. Several key regulatory proteins are involved in the initiation of apoptosis. Caspase-3 plays a direct role in proteolytic cleavage of cellular proteins responsible for progression to apoptosis. We examined the effect of paclitaxel on the cell cycle arrest and apoptosis in U-2 OS cells using flow cytometric analysis and Western blotting. We also measured the inhibition of paclitaxel-induced apoptosis and the caspase-3 activity by the broad-spectrum caspase inhibitor z-VAD-fmk on U-2 OS cells. The increased levels of casapse-3 were also confirmed by cDNA microarray. Our observations were: (1) paclitaxel treatment resulted in G2/M-cycle arrest in U-2 OS cells; (2) time and dose dependent apoptosis of U-2 OS cells was induced by paclitaxel; (3) in U-2 OS cells, z-VAD-fmk blocked the paclitaxel-induced apoptosis and caspase-3 activation. These results suggest that paclitaxel-induced G2/M-cycle arrest of the G2/M phase and apoptosis via a caspase-3 pathway in U-2 OS cells.
authors.affiliation: Department of Orthopaedic Surgery, Chung Shan Medical University Hospital, Taichung 402, Taiwan, ROC.
authors.forename: K-H
authors.initials: KH
authors.lastname: Lu
authors.forename: K-H
authors.initials: KH
authors.lastname: Lue
authors.forename: M-C
authors.initials: MC
authors.lastname: Chou
authors.forename: J-G
authors.initials: JG
authors.lastname: Chung
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001859:Bone Neoplasms / Q000188:drug therapy* / Q000473:pathology; D053148:Caspase 3; D061945:Caspase Inhibitors; D020169:Caspases / Q000502:physiology*; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D006801:Humans; D012516:Osteosarcoma / Q000188:drug therapy* / Q000473:pathology; D017239:Paclitaxel / Q000494:pharmacology*
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D000972:Antineoplastic Agents, Phytogenic; D061945:Caspase Inhibitors; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D017239:Paclitaxel