title: Inhibition of radiation induced migration of human head and neck squamous cell carcinoma cells by blocking of EGF receptor pathways.
abstract: BACKGROUND
  Recently it has been shown that radiation induces migration of glioma cells and facilitates a further spread of tumor cells locally and systemically. The aim of this study was to evaluate whether radiotherapy induces migration in head and neck squamous cell carcinoma (HNSCC). A further aim was to investigate the effects of blocking the epidermal growth factor receptor (EGFR) and its downstream pathways (Raf/MEK/ERK, PI3K/Akt) on tumor cell migration in vitro.
  
  
  METHODS
  Migration of tumor cells was assessed via a wound healing assay and proliferation by a MTT colorimeritric assay using 3 HNSCC cell lines (BHY, CAL-27, HN). The cells were treated with increasing doses of irradiation (2 Gy, 5 Gy, 8 Gy) in the presence or absence of EGF, EGFR-antagonist (AG1478) or inhibitors of the downstream pathways PI3K (LY294002), mTOR (rapamycin) and MEK1 (PD98059). Biochemical activation of EGFR and the downstream markers Akt and ERK were examined by Western blot analysis.
  
  
  RESULTS
  In absence of stimulation or inhibition, increasing doses of irradiation induced a dose-dependent enhancement of migrating cells (p < 0.05 for the 3 HNSCC cell lines) and a decrease of cell proliferation (p < 0.05 for the 3 HNSCC cell lines). The inhibition of EGFR or the downstream pathways reduced cell migration significantly (almost all p < 0.05 for the 3 HNSCC cell lines). Stimulation of HNSCC cells with EGF caused a significant increase in migration (p < 0.05 for the 3 HNSCC cell lines). After irradiation alone a pronounced activation of EGFR was observed by Western blot analysis.
  
  
  CONCLUSIONS
  Our results demonstrate that the EGFR is involved in radiation induced migration of HNSCC cells. Therefore EGFR or the downstream pathways might be a target for the treatment of HNSCC to improve the efficacy of radiotherapy.
authors: Department of Otolaryngology Head and Neck Surgery, Technical University of Munich, Ismaninger Straße 22, 81675 Munich, Germany. a.pickhard@lrz.tum.de
authors: Anja C
authors: AC
authors: Pickhard
authors: Johanna
authors: J
authors: Margraf
authors: Andreas
authors: A
authors: Knopf
authors: Thomas
authors: T
authors: Stark
authors: Guido
authors: G
authors: Piontek
authors: Carolin
authors: C
authors: Beck
authors: Anne-Laure
authors: AL
authors: Boulesteix
authors: Elias Q
authors: EQ
authors: Scherer
authors: Steffi
authors: S
authors: Pigorsch
authors: Jürgen
authors: J
authors: Schlegel
authors: Wolfgang
authors: W
authors: Arnold
authors: Rudolf
authors: R
authors: Reiter
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000201:enzymology / Q000473:pathology* / Q000532:radiotherapy*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects* / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D004815:Epidermal Growth Factor / Q000378:metabolism; D066246:ErbB Receptors / Q000037:antagonists & inhibitors* / Q000378:metabolism; D005419:Flavonoids / Q000494:pharmacology; D005720:Gamma Rays; D006258:Head and Neck Neoplasms / Q000188:drug therapy / Q000201:enzymology / Q000473:pathology* / Q000532:radiotherapy*; D006801:Humans; D048369:MAP Kinase Kinase 1 / Q000378:metabolism; D020935:MAP Kinase Signaling System; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011799:Quinazolines / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D020123:Sirolimus / Q000494:pharmacology; D000077195:Squamous Cell Carcinoma of Head and Neck; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism; D020032:Tyrphostins / Q000494:pharmacology
chemical_list: D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D005419:Flavonoids; D048369:MAP Kinase Kinase 1; D019869:Phosphatidylinositol 3-Kinases; D011799:Quinazolines; D020123:Sirolimus; D058570:TOR Serine-Threonine Kinases; D020032:Tyrphostins; C101044:RTKI cpd; C546842:MTOR protein, human; C482125:MAP2K1 protein, human; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one