title: In vitro study of normoxic epidermal growth factor receptor-induced hypoxia-inducible factor-1-alpha, vascular endothelial growth factor, and BNIP3 expression in head and neck squamous cell carcinoma cell lines: Implications for anti-epidermal growth factor receptor therapy.
abstract: BACKGROUND
  We previously showed that activation of epidermal growth factor receptor (EGFR) induces hypoxia inducible factor-1α (HIF-1α) in head and neck squamous cell carcinoma (HNSCC) cells. In this study, we have furthered this by investigating the mechanism of HIF-1α activation by epidermal growth factor (EGF) and its association with the sensitivity to gefitinib.
  
  
  METHODS
  EGFR/HIF-1α signaling was tested by immunoblot, polymerase chain reaction (PCR), cell proliferation, and apoptosis assays.
  
  
  RESULTS
  HIF-1α accumulated in cells overexpressing EGF and phosphorylated epidermal growth factor receptor (pEGFR), phosphatidylinositol-3-kinase (pPI3K), and mitogen-activated protein kinase (pMAPK). EGF-induced expression of HIF-1α and its targets, vascular endothelial growth factor (VEGF) and BNIP3, were blocked by gefitinib and PI3K-inhibitors and MAPK-inhibitors. HIF-1α-siRNAs abrogated EGF-induced BNIP3 but not VEGF expression. Gefitinib inhibited cell proliferation and induced apoptosis more strongly in cells with constitutively active EGFR/HIF-1α signaling than in cells lacking activation of these pathways. HIF-1α-siRNA treatment reduced sensitivity to gefitinib.
  
  
  CONCLUSIONS
  The search for molecular predictors of sensitivity to gefitinib in HNSCC should be extended to the activation status of EGFR-downstream pathways, phosphorylated protein kinase B, pMAPK, and HIF-1α.
authors.affiliation: Servicio de Otorrinolaringología, Hospital Universitario Central de Asturias, Instituto Universitario de Oncología del Principado de Asturias, Universidad de Oviedo, Oviedo, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: Secades
authors.affiliation: Servicio de Otorrinolaringología, Hospital Universitario Central de Asturias, Instituto Universitario de Oncología del Principado de Asturias, Universidad de Oviedo, Oviedo, Spain.
authors.forename: Inés Saenz
authors.initials: IS
authors.lastname: de Santa-María
authors.affiliation: Servicio de Otorrinolaringología, Hospital Universitario Central de Asturias, Instituto Universitario de Oncología del Principado de Asturias, Universidad de Oviedo, Oviedo, Spain.
authors.forename: Anna
authors.initials: A
authors.lastname: Merlo
authors.affiliation: Servicio de Otorrinolaringología, Hospital Universitario Central de Asturias, Instituto Universitario de Oncología del Principado de Asturias, Universidad de Oviedo, Oviedo, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Suarez
authors.affiliation: Servicio de Otorrinolaringología, Hospital Universitario Central de Asturias, Instituto Universitario de Oncología del Principado de Asturias, Universidad de Oviedo, Oviedo, Spain.
authors.forename: María-Dolores
authors.initials: MD
authors.lastname: Chiara
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000077156:Gefitinib; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006258:Head and Neck Neoplasms / Q000188:drug therapy / Q000378:metabolism*; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D015151:Immunoblotting; D066298:In Vitro Techniques; D008565:Membrane Proteins / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011237:Predictive Value of Tests; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D011799:Quinazolines / Q000494:pharmacology; D012680:Sensitivity and Specificity; D015398:Signal Transduction; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; C090121:BNIP3 protein, human; D014408:Biomarkers, Tumor; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D011799:Quinazolines; D042461:Vascular Endothelial Growth Factor A; D066246:ErbB Receptors; D000077156:Gefitinib
keywords: BNIP3; epidermal growth factor; gefitinib; head and neck squamous cell carcinoma; hypoxia inducible factor