title: The influence of retinoic Acid and thalidomide on the radiosensitivity of u343 glioblastoma cells.
abstract: OBJECTIVE
  13-cis-retinoic acid (RA) and thalidomide have shown a synergistic anti-proliferative effect on U343 glioblastoma (GBM) cells. In the present study, we test if their combined treatment might enhance the radiosensitivity of these cells.
  
  
  METHODS
  The radiosensitivity of U343 GBM cells was determined by the colony formation assay. Fibroblast growth factor-2 (FGF2) gene expression was determined by a quantitative polymerase chain reaction (qPCR).
  
  
  RESULTS
  RA up-regulated FGF2 gene expression, which was abrogated by thalidomide. No radiosensitisation by RA was observed under standard culture conditions with 10% serum, but enhanced radiosensitivity was observed under 1% serum during irradiation. However, a synergistic effect with thalidomide was not observed.
  
  
  CONCLUSIONS
  Growth factors in the culture medium may mask radiosensitization by RA while autocrine expression of FGF2 did not seem to be protective. Importantly, the anti-proliferative effect of RA in combination with thalidomide would not compromise the radiosensitivity of these GBM cells.
authors.affiliation: University Hospital Freiburg, Department of Radiation Oncology, Robert Koch Strasse 3, D-79106 Freiburg, Germany. dusan.milanovic@uniklinik-freiburg.de.
authors.forename: Dušan
authors.initials: D
authors.lastname: Milanović
authors.forename: Patrick
authors.initials: P
authors.lastname: Maier
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Schanne
authors.forename: Frederik
authors.initials: F
authors.lastname: Wenz
authors.forename: Carsten
authors.initials: C
authors.lastname: Herskind
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D018929:Cell Culture Techniques; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D016222:Fibroblast Growth Factor 2 / Q000235:genetics / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D005909:Glioblastoma / Q000188:drug therapy / Q000235:genetics / Q000532:radiotherapy; D006801:Humans; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D011836:Radiation Tolerance / Q000187:drug effects*; D013792:Thalidomide / Q000494:pharmacology*; D014212:Tretinoin / Q000494:pharmacology*; D014410:Tumor Stem Cell Assay
chemical_list: D000970:Antineoplastic Agents; D016222:Fibroblast Growth Factor 2; D013792:Thalidomide; D014212:Tretinoin
keywords: Radiosensitivity; glioblastoma cells; retinoic acid; thalidomide