title: Interleukin-8 as a modulator of response to bevacizumab in preclinical models of head and neck squamous cell carcinoma.
abstract: OBJECTIVE
  Bevacizumab, a monoclonal antibody to VEGF-A, is under active clinical evaluation in head and neck squamous cell carcinoma (HNSCC) and appears to be a promising therapy in at least a subset of patients. However, there are no reliable predictive biomarkers to identify those patients most likely to benefit. In this study, we assessed the efficacy of bevacizumab in HNSCC xenograft models to characterize escape mechanisms underlying intrinsic resistance and identify potential biomarkers of drug response.
  
  
  METHODS
  We evaluated the angiogenic profile of HNSCC cells from sensitive and resistant cell lines using antibody array. We further examined the role of interleukin-8 (IL-8) in contributing to resistance both in vitro and in vivo, using a loss- and gain-of-function approach.
  
  
  RESULTS
  Angiogenic profiling indicated that resistant cells expressed higher levels of proangiogenic factors including IL-8, interleukin-1α (IL-1α), vascular endothelial growth factor (VEGF), fibroblast growth factor-a (FGF-a), and tumor necrosis factor-α (TNF-α). IL-8 was the most differentially expressed protein. IL-8 signaling compensated for VEGF inhibition in endothelial cells. Downregulation of IL-8 resulted in sensitization of resistant tumors to bevacizumab by disrupting angiogenesis and enhancing endothelial cell apoptosis. Overexpression of IL-8 in sensitive tumors conferred resistance to bevacizumab. Serum analysis of HNSCC patients treated with a bevacizumab-containing regime revealed high baseline IL-8 levels in a subset of patients refractory to treatment but not in responders.
  
  
  CONCLUSIONS
  These results implicate IL-8 in mediating intrinsic resistance to bevacizumab in HNSCC. Hence, co-targeting of VEGF and IL-8 may help overcome resistance and enhance therapeutic efficacy.
authors.affiliation: Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
authors.forename: Rekha
authors.initials: R
authors.lastname: Gyanchandani
authors.forename: Daisuke
authors.initials: D
authors.lastname: Sano
authors.forename: Marcus V
authors.initials: MV
authors.lastname: Ortega Alves
authors.forename: Jonah D
authors.initials: JD
authors.lastname: Klein
authors.forename: Beth A
authors.initials: BA
authors.lastname: Knapick
authors.forename: Sanders
authors.initials: S
authors.lastname: Oh
authors.forename: Jeffrey N
authors.initials: JN
authors.lastname: Myers
authors.forename: Seungwon
authors.initials: S
authors.lastname: Kim
mesh_terms: D000818:Animals; D061067:Antibodies, Monoclonal, Humanized / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001483:Base Sequence; D000068258:Bevacizumab; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy* / Q000503:physiopathology; D017931:DNA Primers; D015536:Down-Regulation; D005260:Female; D006258:Head and Neck Neoplasms / Q000188:drug therapy* / Q000503:physiopathology; D006801:Humans; D016209:Interleukin-8 / Q000097:blood / Q000502:physiology*; D051379:Mice; D008819:Mice, Nude; D009389:Neovascularization, Pathologic; D015854:Up-Regulation; D023041:Xenograft Model Antitumor Assays
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D017931:DNA Primers; D016209:Interleukin-8; D000068258:Bevacizumab
keywords: Angiogenesis; Bevacizumab; Biomarker; EGFR; FGF-a; GCSF; HNSCC; IL-1α; IL-8; IUCUC; MVD; RCC; Resistance; TNF-α; TUNEL; UPCI; VEGF; VEGFR; epidermal growth factor receptor; fibroblast growth factor-a; granulocyte colony stimulating factor; head and neck squamous cell carcinoma; institutional animal care and use committee; interleukin-1α; interleukin-8; microvessel density; renal cell carcinoma; terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling; tumor necrosis factor-α; university of pittsburgh cancer institute; vascular endothelial growth factor; vascular endothelial growth factor receptor