title: Bid truncation mediated by caspases-3 and -9 in vinorelbine-induced apoptosis.
abstract: Vinorelbine is a chemotherapeutic vinca alkaloid clinically prescribed for non-small cell lung cancer and breast cancer. Here we studied the mechanism for vinorelbine-induced apoptosis in a human T-cell lymphoma. Although vinorelbine induces DNA fragmentation that is inhibited by specific peptide inhibitors for caspases-9 and -3 in Jurkat cells, caspase-8 deficiency retards vinorelbine-induced apoptosis. Activation of caspase-8 is also observed in vinorelbine-treated cells, and the activity is diminished when the caspase-3 activity is blocked by a specific peptide inhibitor, Ac-DNLC-CHO. Blocking of the Fas receptor with an antagonistic anti-Fas antibody does not affect vinorelbine-induced DNA fragmentation. These results suggest that vinorelbine-induced apoptosis is enhanced by the activation of caspase-8 via caspase-9-mediated activation of caspase-3, but not through a Fas-triggered signal. Western blotting suggests that vinorelbine cleaves caspase-3, -9 and -8 and reduces the amount of mitochondrial cytochrome c. Caspase-8 deficiency suppresses all of these events. A downstream substrate for caspase-8, Bid, is also cleaved in vinorelbine-treated cells, but the Bid truncation is also observed in caspase-8-deficient Jurkat cells. Importantly, recombinant caspases-3 and -9, as well as caspase-8, directly cleaves recombinant Bid in vitro. These results suggest that caspases-3 and -9 participate in Bid truncation, indicating a new mechanism for vinorelbine-induces apoptosis.
authors.affiliation: Faculty of Science and Engineering, Tokyo University of Science, Yamaguchi, Japan.
authors.forename: Akemi
authors.initials: A
authors.lastname: Hayakawa
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kawamoto
authors.forename: Hiroo
authors.initials: H
authors.lastname: Nakajima
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Sakai
authors.forename: Ryoko
authors.initials: R
authors.lastname: Takasawa
authors.forename: Izumi
authors.initials: I
authors.lastname: Nakashima
authors.forename: Junji
authors.initials: J
authors.lastname: Magae
authors.forename: Sei-ichi
authors.initials: S
authors.lastname: Tanuma
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D051023:BH3 Interacting Domain Death Agonist Protein / Q000378:metabolism*; D053148:Caspase 3 / Q000502:physiology*; D053181:Caspase 8 / Q000502:physiology; D053453:Caspase 9 / Q000502:physiology*; D045744:Cell Line, Tumor; D045304:Cytochromes c / Q000378:metabolism; D006801:Humans; D019169:Jurkat Cells; D016399:Lymphoma, T-Cell / Q000188:drug therapy* / Q000473:pathology; D014747:Vinblastine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D000077235:Vinorelbine
chemical_list: D051023:BH3 Interacting Domain Death Agonist Protein; C494814:BID protein, human; D014747:Vinblastine; D045304:Cytochromes c; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D000077235:Vinorelbine