title: TRAIL and interferon-alpha act synergistically to induce renal cell carcinoma apoptosis.
abstract: OBJECTIVE
  Despite modern targeted therapy metastatic renal cell carcinoma remains a deadly disease. Interferon-alpha (Calbiochem(R)) is currently used to treat this condition, mainly combined with the targeted anti-vascular endothelial growth factor antibody bevacizumab. TRAIL (Apo2 ligand/tumor necrosis factor related apoptosis inducing ligand) (Calbiochem) is a novel antineoplastic agent now in early phase clinical trials. Interferon-alpha and TRAIL can act synergistically to kill cancer cells but to our knowledge this has never been tested in the context of renal cell carcinoma. We hypothesized that TRAIL and interferon-alpha could synergistically induce apoptosis in renal cell carcinoma cells.
  
  
  METHODS
  We treated renal cell carcinoma cell lines with recombinant TRAIL and/or interferon-alpha. Viability and apoptosis were assessed by MTS assay, flow cytometry and Western blot. Synergy was confirmed by isobologram. Interferon-alpha induced changes in renal cell carcinoma cell signaling were assessed by Western blot, flow cytometry and enzyme-linked immunosorbent assay.
  
  
  RESULTS
  TRAIL and interferon-alpha acted synergistically to increase apoptotic cell death in renal cell carcinoma cells. Interferon-alpha treatment altered the ability of cells to activate extracellular signal-regulated kinase while inhibiting extracellular signal-regulated kinase with UO126 abrogated TRAIL and interferon-alpha apoptotic synergy. Interferon-alpha did not induce changes in TRAIL or death receptor expression, or change other known mediators of the intrinsic and extrinsic apoptotic cascade in the cells.
  
  
  CONCLUSIONS
  TRAIL plus interferon-alpha synergistically induces apoptosis in renal cell carcinoma cells, which is due at least in part to interferon-alpha mediated changes in extracellular signal-regulated kinase activation. TRAIL and interferon-alpha combination therapy may be a novel approach to advanced renal cell carcinoma that warrants further testing in vivo.
authors.affiliation: Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2765, USA. peter.clark@vanderbilt.edu
authors.forename: Peter E
authors.initials: PE
authors.lastname: Clark
authors.forename: Dina A
authors.initials: DA
authors.lastname: Polosukhina
authors.forename: Kenneth
authors.initials: K
authors.lastname: Gyabaah
authors.forename: Harold L
authors.initials: HL
authors.lastname: Moses
authors.forename: Andrew
authors.initials: A
authors.lastname: Thorburn
authors.forename: Roy
authors.initials: R
authors.lastname: Zent
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D002292:Carcinoma, Renal Cell / Q000473:pathology*; D045744:Cell Line, Tumor; D004357:Drug Synergism; D006801:Humans; D016898:Interferon-alpha / Q000494:pharmacology*; D007680:Kidney Neoplasms / Q000473:pathology*; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000494:pharmacology*
chemical_list: D016898:Interferon-alpha; D053221:TNF-Related Apoptosis-Inducing Ligand