title: Tumor Growth Suppression and Enhanced Radioresponse by an Exogenous Epidermal Growth Factor in Mouse Xenograft Models with A431 Cells.
abstract: OBJECTIVE
  The purpose of this study was to evaluate whether an exogenous epidermal growth factor (EGF) could induce anti-tumor and radiosensitizing effects in vivo.
  
  
  METHODS
  BALB/c-nu mice that were inoculated with A431 (human squamous cell carcinoma) cells in the right hind legs were divided into five groups: I (no treatment), II (EGF for 6 days), III (EGF for 20 days), IV (radiotherapy [RT]), and V (RT plus concomitant EGF). EGF was administered intraperitoneally (5 mg/kg) once a day and the RT dose was 30 Gy in six fractions. Hematoxylin and eosin (H&E) stained sections of tumor, liver, lung, and kidney tissues were investigated. Additionally, tumors were subjected to immunohistochemistry staining with caspase-3.
  
  
  RESULTS
  EGF for 6 days decreased tumor volume, but it approached the level of the control group at the end of follow-up (p=0.550). The duration of tumor shrinkage was prolonged in group V while the slope of tumor re-growth phase was steeper in group IV (p=0.034). EGF for 20 days decreased tumor volume until the end of the observation period (p < 0.001). Immunohistochemistry revealed that mice in group V showed stronger intensity than those in group IV. There were no abnormal histological findings upon H&E staining of the normal organs.
  
  
  CONCLUSIONS
  EGF-induced anti-tumor effect was ascertained in the xenograft mouse models with A431 cells. Concomitant use of EGF has the potential role as a radiosensitizer in the design of fractionated irradiation.
authors.affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Yu Jin
authors.initials: YJ
authors.lastname: Lim
authors.affiliation: Cancer Research Institution, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Sang-Rok
authors.initials: SR
authors.lastname: Jeon
authors.affiliation: Department of Pathology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Jae Moon
authors.initials: JM
authors.lastname: Koh
authors.affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea.|Cancer Research Institution, Seoul National University College of Medicine, Seoul, Korea.|Institute of Radiation Medicine, Medical Research Center, Seoul National University, Seoul, Korea.
authors.forename: Hong-Gyun
authors.initials: HG
authors.lastname: Wu
mesh_terms: D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy* / Q000532:radiotherapy*; D045744:Cell Line, Tumor; D004815:Epidermal Growth Factor / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D009374:Neoplasms, Experimental / Q000188:drug therapy* / Q000532:radiotherapy*; D011878:Radiotherapy
chemical_list: D004815:Epidermal Growth Factor
keywords: Antineoplastic agents; Apoptosis; Epidermal growth factor; Radiation-sensitizing agents; Xenograft model antitumor assays