title: Molecular determinants of epothilone B derivative (BMS 247550) and Apo-2L/TRAIL-induced apoptosis of human ovarian cancer cells.
abstract: OBJECTIVE
  We determined the cytotoxic effects BMS 247550 (Epo B), a derivative of epothilone B, on cisplatinum- or paclitaxel-sensitive or -resistant human ovarian cancer cells. Additionally, we determined the effect of Epo B on Apo-2L/TRAIL-induced apoptosis of ovarian cancer cells.
  
  
  METHODS
  Epo B-induced cytotoxic and cell cycle effects were evaluated by the MTT assay and flow cytometry, respectively. Epo B-induced apoptosis was assessed by immunoblot analyses of the processing and proteolytic activity of caspases, flow cytometric measurement of annexin V staining, and the TUNEL assay. The effects of Epo B and/or Apo-2L/TRAIL on the protein expressions of the death receptors DR4 and DR5 as well as of XIAP and survivin were determined by immunoblot analyses.
  
  
  RESULTS
  In the cell cycle-synchronized ovarian cancer cells, Epo B induced tubulin polymerization and mitotic arrest, followed by apoptosis. This was associated with the cytosolic accumulation of cytochrome (cyt) c and Smac/DIABLO as well as PARP cleavage activity of caspase-3. Epo B was able to exert cytotoxic effects against cisplatinum- and paclitaxel-resistant ovarian cancer cells. Epo B increased the expressions of DR4 and DR5, as well as augmented Apo-2L/TRAIL-induced processing of caspase-8 and Bid. This was associated with more caspase-3 activity, a decline in the intracellular levels of XIAP, cIAP, and survivin, and apoptosis of ovarian cancer cells.
  
  
  CONCLUSIONS
  These data support the in vivo testing of Epo B against cisplatinum- and paclitaxel-resistant ovarian cancers, and suggest that a pretreatment with Epo B may sensitize human ovarian cancers to the cytotoxic effects of Apo-2L/TRAIL.
authors.affiliation: Interdisciplinary Oncology Program, Moffitt Cancer Center and Research Institute, University of South Florida, Tampa, FL 33612, USA.
authors.forename: David
authors.initials: D
authors.lastname: Griffin
authors.forename: Sylvie
authors.initials: S
authors.lastname: Wittmann
authors.forename: Fei
authors.initials: F
authors.lastname: Guo
authors.forename: Ramadevi
authors.initials: R
authors.lastname: Nimmanapalli
authors.forename: Purva
authors.initials: P
authors.lastname: Bali
authors.forename: Hong Gang
authors.initials: HG
authors.lastname: Wang
authors.forename: Kapil
authors.initials: K
authors.lastname: Bhalla
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D051017:Apoptosis Regulatory Proteins; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002945:Cisplatin / Q000494:pharmacology; D003574:Cytochrome c Group / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D004357:Drug Synergism; D034261:Epothilones / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D008562:Membrane Glycoproteins / Q000008:administration & dosage / Q000494:pharmacology*; D008869:Microtubule-Associated Proteins / Q000096:biosynthesis; D008938:Mitosis / Q000187:drug effects; D009363:Neoplasm Proteins; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D017239:Paclitaxel / Q000494:pharmacology; D014176:Protein Biosynthesis; D011506:Proteins; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000494:pharmacology; D000077022:Survivin; D053221:TNF-Related Apoptosis-Inducing Ligand; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000008:administration & dosage / Q000494:pharmacology*; D051636:X-Linked Inhibitor of Apoptosis Protein
chemical_list: D051017:Apoptosis Regulatory Proteins; C107489:BIRC5 protein, human; D003574:Cytochrome c Group; D034261:Epothilones; D051034:Inhibitor of Apoptosis Proteins; D008562:Membrane Glycoproteins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D011506:Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011994:Recombinant Proteins; D000077022:Survivin; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha; D051636:X-Linked Inhibitor of Apoptosis Protein; C496866:XIAP protein, human; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; C430592:ixabepilone; D017239:Paclitaxel; D002945:Cisplatin