title: Pazopanib synergizes with docetaxel in the treatment of bladder cancer cells.
abstract: OBJECTIVE
  To investigate the efficacy of pazopanib, both alone and in combination with docetaxel, in bladder cancer cells. Bladder cancer expresses many potential therapeutic targets of biological agents, including the vascular endothelial growth factor receptor (VEGFR). Pazopanib is a small molecule inhibitor of VEGFR-1, -2-3, platelet-derived growth factor receptor (PDGFR), and c-Kit.
  
  
  METHODS
  Using human bladder cancer cells HTB3, HT1376, J82, RT4, CRL1749, T24, Sup, and HTB9, the treatment effect of pazopanib and cytotoxic chemotherapy was assessed using a tetrazolium-based assay. The combinatorial effect of these agents on clonogenic growth was further examined. Western blotting was used to assess changes in relevant downstream targets, including phospho-AKT, phospho-FAK, total AKT, and total FAK.
  
  
  RESULTS
  Single-agent pazopanib had modest activity. However, synergy was seen with the combination of docetaxel and pazopanib in these multiple cells lines. J82 and T24 cells were selected for additional clonogenic testing because of their resistance to single-agent docetaxel chemotherapy. 1.25 nM of docetaxel had little effect on clonogenic formation; however, in combination with pazopanib, significant inhibition of colony formation was observed. This combination treatment additionally decreased phospho-AKT, an important mediator of cell survival in all cell lines, whereas phospho-FAK expression was variably affected.
  
  
  CONCLUSIONS
  The present study demonstrates synergistic efficacy of pazopanib with docetaxel in docetaxel-resistant bladder cancer cells. This work supports future evaluation of pazopanib with docetaxel for the treatment of bladder cancer with the potential of improved efficacy and toxicity.
authors.affiliation: Department of Medicine, Division of Medical Oncology, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Yang
authors.forename: Lih-Jen
authors.initials: LJ
authors.lastname: Su
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Flaig
mesh_terms: D000970:Antineoplastic Agents / Q000627:therapeutic use*; D000077143:Docetaxel; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D006801:Humans; D007191:Indazoles; D011743:Pyrimidines / Q000627:therapeutic use*; D013449:Sulfonamides / Q000627:therapeutic use*; D043823:Taxoids / Q000627:therapeutic use*; D014407:Tumor Cells, Cultured; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy* / Q000473:pathology
chemical_list: D000970:Antineoplastic Agents; D007191:Indazoles; D011743:Pyrimidines; D013449:Sulfonamides; D043823:Taxoids; D000077143:Docetaxel; C516667:pazopanib