title: Interferon-alpha enhances sensitivity of human osteosarcoma U2OS cells to doxorubicin by p53-dependent apoptosis.
abstract: OBJECTIVE
  To determine whether interferon-alpha(IFNalpha) can enhance doxorubicin sensitivity in osteosarcoma cells and its molecular mechanism.
  
  
  METHODS
  Cell viability was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Apoptosis was studied using Flow cytometry analysis, Hoechst33258 staining, DNA fragmentation assay, as well as the activation of caspase-3 and poly (ADP-ribose) polymerase. Protein expression was detected by Western blotting. The dependence of p53 was determined using p53-siRNA transfection.
  
  
  RESULTS
  IFNalpha increased doxorubicin-induced cytotoxicity to a much greater degree through apoptosis in human osteosarcoma p53-wild U2OS cells, but not p53-mutant MG63 cells. IFNalpha markedly upregulated p53, Bax, Mdm2, and p21, downregulated Bcl-2, and activated caspase-3 and PARP cleavage in response to doxorubicin in U2OS cells. Moreover, the siRNA-mediated silencing of p53 significantly reduced the IFNalpha/doxorubicin combination-induced cytotoxicity and PARP cleavage.
  
  
  CONCLUSIONS
  IFNalpha enhances the sensitivity of human osteosarcoma U2OS cells to doxorubicin by p53-dependent apoptosis. The proper combination with IFNalpha and conventional chemotherapeutic agents may be a rational strategy for improving the treatment of osteosarcoma with functional p53.
authors.affiliation: Department of Orthopedic Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China.
authors.forename: Xiang-wei
authors.initials: XW
authors.lastname: Yuan
authors.forename: Xiao-feng
authors.initials: XF
authors.lastname: Zhu
authors.forename: Xiu-fang
authors.initials: XF
authors.lastname: Huang
authors.forename: Pu-yi
authors.initials: PY
authors.lastname: Sheng
authors.forename: Ai-shan
authors.initials: AS
authors.lastname: He
authors.forename: Zi-bo
authors.initials: ZB
authors.lastname: Yang
authors.forename: Rong
authors.initials: R
authors.lastname: Deng
authors.forename: Gong-kan
authors.initials: GK
authors.lastname: Feng
authors.forename: Wei-ming
authors.initials: WM
authors.lastname: Liao
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000008:administration & dosage / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D004317:Doxorubicin / Q000008:administration & dosage / Q000494:pharmacology*; D004357:Drug Synergism; D016158:Genes, p53 / Q000502:physiology; D006801:Humans; D066298:In Vitro Techniques; D016898:Interferon-alpha / Q000008:administration & dosage / Q000494:pharmacology*; D009154:Mutation; D012516:Osteosarcoma / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D015533:Transcriptional Activation
chemical_list: D000903:Antibiotics, Antineoplastic; D016898:Interferon-alpha; D004317:Doxorubicin