title: Celecoxib enhances radiation response of secondary bone tumors of a human non-small cell lung cancer via antiangiogenesis in vivo.
abstract: OBJECTIVE
  Cyclooxygenase-2 (COX-2) inhibitors mediate a systemic antitumor activity via antiangiogenesis and seem to enhance the response of primary tumors to radiation. Radiosensitizing effects of COX-2 inhibition have not been reported for bone metastases. Therefore, the aim of this study was the investigation of the radiosensitizing effects of the selective COX-2 inhibitor celecoxib in secondary bone tumors of a non-small cell lung carcinoma in vivo.
  
  
  METHODS
  Human A549 lung carcinomas were implanted into a cranial window preparation in male SCID mice (n = 24). Animals were treated with either celecoxib or radiation (7 Gy single photon dose) alone or a combination of celecoxib and radiation, respectively. Untreated animals served as controls. The impact of radiation and COX-2 inhibition on angiogenesis, microcirculation, and tumor growth was analyzed over 28 days by means of intravital microscopy and histological methods.
  
  
  RESULTS
  Monotherapies with radiation as well as celecoxib had significant antitumor effects compared to untreated controls. Both therapies reduced tumor growth and vascularization to a similar extent. The simultaneous administration of celecoxib and radiation further enhanced the antitumor and antiangiogenic effects of single-beam radiation. With the combined treatment approach, tumor vascularization and tumor size were decreased by 57% and 51%, respectively, as compared to monotherapy with radiation.
  
  
  CONCLUSIONS
  The combined application of radiation therapy and COX-2 inhibition showed synergistic effects concerning the inhibition of tumor growth and tumor angiogenesis. Therefore, the combination of radiation with COX-2 inhibitor therapy represents a promising approach to improve the therapeutic efficacy of radiotherapy of bone metastases.
authors.affiliation: Department of Orthopedic Surgery, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Frank Michael
authors.initials: FM
authors.lastname: Klenke
authors.forename: Amir
authors.initials: A
authors.lastname: Abdollahi
authors.forename: Marc
authors.initials: M
authors.lastname: Bischof
authors.forename: Martha-Maria
authors.initials: MM
authors.lastname: Gebhard
authors.forename: Volker
authors.initials: V
authors.lastname: Ewerbeck
authors.forename: Peter E
authors.initials: PE
authors.lastname: Huber
authors.forename: Axel
authors.initials: A
authors.lastname: Sckell
mesh_terms: D020533:Angiogenesis Inhibitors / Q000494:pharmacology*; D000818:Animals; D001859:Bone Neoplasms / Q000098:blood supply / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy* / Q000556:secondary*; D002289:Carcinoma, Non-Small-Cell Lung / Q000098:blood supply / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy* / Q000556:secondary*; D000068579:Celecoxib; D002455:Cell Division / Q000187:drug effects / Q000528:radiation effects; D003131:Combined Modality Therapy; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology*; D046169:Dermoscopy; D006801:Humans; D008175:Lung Neoplasms / Q000098:blood supply / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D051379:Mice; D016513:Mice, SCID; D008856:Microscopy, Fluorescence; D018715:Microscopy, Video; D009389:Neovascularization, Pathologic / Q000473:pathology; D011720:Pyrazoles / Q000494:pharmacology*; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*; D013449:Sulfonamides / Q000494:pharmacology*; D047368:Tumor Burden
chemical_list: D020533:Angiogenesis Inhibitors; D052246:Cyclooxygenase 2 Inhibitors; D011720:Pyrazoles; D011838:Radiation-Sensitizing Agents; D013449:Sulfonamides; D000068579:Celecoxib