title: Epothilone B enhances surface EpCAM expression in ovarian cancer Hey cells.
abstract: OBJECTIVE
  Epothilone B (EpoB), like Taxol, stabilizes microtubules resulting in an inhibition of microtubule dynamic instability. The drug is being evaluated in phase III clinical trials. An EpoB analog, Ixabepilone, was approved by the FDA for the treatment of taxane-resistant metastatic breast cancer. Epithelial cell adhesion antigen (EpCAM) expression is significantly higher in epithelial ovarian cancer cells compared to normal cells. The effects of EpoB and other microtubule-interacting agents on surface EpCAM expression were studied.
  
  
  METHODS
  Biochemical methods, immunofluorescence and flow cytometry were used to identify EpCAM expression on the surface of the ovarian cancer cell line, Hey, after exposure to EpoB. The relationship between EpoB-mediated surface EpCAM expression and EpoB-induced α-tubulin acetylation, a surrogate marker for stable microtubules, in Hey cells also was investigated.
  
  
  RESULTS
  Nanomolar concentrations of EpoB, Taxol, discodermolide or vinblastine caused a marked increase in surface EpCAM expression in Hey cells. Alpha-tubulin acetylation was increased following treatment with Taxol, EpoB and discodermolide, but not with vinblastine, indicating that drug-enhanced surface EpCAM expression does not correlate with tubulin acetylation or stabilization. Unexpectedly, EpoB did not have a significant effect on EpCAM mRNA expression, nor did it alter the level of total cellular EpCAM in Hey cells.
  
  
  CONCLUSIONS
  The results indicate that disruption of the microtubule cytoskeleton is associated with the redistribution of cell surface antigens in ovarian cancer cells. The increase in cell surface EpCAM antigen density may facilitate the antibody targeting of EpCAM-positive ovarian cancer cells.
authors.affiliation: Division of Gynecologic Oncology, Department of Obstetrics & Gynecology and Women's Health, Montefiore Medical Center Bronx, NY 10461, USA.
authors.forename: Shohreh
authors.initials: S
authors.lastname: Shahabi
authors.forename: Chia-Ping Huang
authors.initials: CP
authors.lastname: Yang
authors.forename: Gary L
authors.initials: GL
authors.lastname: Goldberg
authors.forename: Susan Band
authors.initials: SB
authors.lastname: Horwitz
mesh_terms: D000107:Acetylation / Q000187:drug effects; D000473:Alkanes / Q000494:pharmacology; D000951:Antigens, Neoplasm / Q000096:biosynthesis*; D002219:Carbamates / Q000494:pharmacology; D015815:Cell Adhesion Molecules / Q000096:biosynthesis*; D045744:Cell Line, Tumor; D000071858:Epithelial Cell Adhesion Molecule; D034261:Epothilones / Q000494:pharmacology*; D005260:Female; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D007783:Lactones / Q000494:pharmacology; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000378:metabolism*; D017239:Paclitaxel / Q000494:pharmacology; D011753:Pyrones / Q000494:pharmacology; D014404:Tubulin / Q000378:metabolism; D050257:Tubulin Modulators / Q000494:pharmacology; D014747:Vinblastine / Q000494:pharmacology
chemical_list: D000473:Alkanes; D000951:Antigens, Neoplasm; D002219:Carbamates; D015815:Cell Adhesion Molecules; C499379:EPCAM protein, human; D000071858:Epithelial Cell Adhesion Molecule; D034261:Epothilones; D006877:Hydroxamic Acids; D007783:Lactones; D011753:Pyrones; D014404:Tubulin; D050257:Tubulin Modulators; C012589:trichostatin A; D014747:Vinblastine; C071229:discodermolide; D017239:Paclitaxel; C093788:epothilone B