title: The effects of tibolone on the human primary glioblastoma multiforme cell culture and the rat C6 glioma model.
abstract: OBJECTIVE
  In the light of recent advances in tumor biology and genetics, we hypothesized that tibolone, an estrogen receptor agonist, may have antiproliferative effects on primary human glioblastoma cells and rat C6 malignant glioma cell lines. We thought that tibolone should exert its antiproliferative effects by augmenting glial cell differentiation through the naive, nonhypermethylated estrogen receptors in the glioma cells.
  
  
  METHODS
  Human primary glioblastoma multiforme (GBM) cells were acquired perioperatively from ten patients aged between 45 and 69 years, diagnosed clinically and radiologically with GBM. The diagnosis was confirmed using immunohistochemical assays. Human GBM and rat C6 malignant glioma cells were cultivated in vitro to obtain monolayer cell cultures. Tibolone was then applied to these cultures in wells, each containing 500,000 tumor cells.
  
  
  RESULTS
  Tibolone significantly decreased the number of human GBM cells at the concentrations of 10 and 100 mg/ml. For tibolone, a strong dose-dependent correlation in tumor inhibition was found (p=0.001). This antiproliferative effect of tibolone in human GBM cells was not observed in rat C6 malignant glioma cells. Tibolone demonstrated differential effects on human GBM and rat C6 glioma cells.
  
  
  CONCLUSIONS
  In vitro antiproliferative effects of tibolone on human GBM need to be investigated further in in vivo works.
authors.affiliation: Istanbul University, Istanbul, Turkey.
authors.forename: Meric A
authors.initials: MA
authors.lastname: Altinoz
authors.forename: Serdar Baki
authors.initials: SB
authors.lastname: Albayrak
authors.forename: Aykut
authors.initials: A
authors.lastname: Karasu
authors.forename: Pulat Akin
authors.initials: PA
authors.lastname: Sabanci
authors.forename: Murat
authors.initials: M
authors.lastname: Imer
authors.forename: Ayhan
authors.initials: A
authors.lastname: Bilir
mesh_terms: D000818:Animals; D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology / Q000627:therapeutic use; D001932:Brain Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D002452:Cell Count; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005909:Glioblastoma / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D005910:Glioma / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D006801:Humans; D007150:Immunohistochemistry; D009652:Norpregnenes / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D011960:Receptors, Estrogen / Q000187:drug effects / Q000378:metabolism; D013045:Species Specificity; D016896:Treatment Outcome
chemical_list: D018931:Antineoplastic Agents, Hormonal; D009652:Norpregnenes; D011960:Receptors, Estrogen; C027385:tibolone