Type I interferon and TNFalpha cooperate with type II interferon for TRAIL induction and triggering of apoptosis in SK-N-MC EWING tumor cells.
Ewing's sarcoma is the second most common human bone tumor in childhood. Here, we investigated the sensitivity of the Ewing tumor cell line, SK-N-MC, to the apoptotic effect of type I (IFNalpha) and type II (IFNgamma) interferons and TNFalpha. We demonstrate that although IFNalpha and TNFalpha alone are unable to induce cell death, they act in synergy with IFNgamma to induce SK-N-MC cell apoptosis. The synergistic induction of apoptosis correlated with the synergistic induction of TNFalpha-related apoptosis-inducing ligand (TRAIL) mRNA and TRAIL protein synthesis as well as of TRAIL secretion. Preparations of inducer-free supernatants from SK-N-MC cells stimulated with combinations of cytokines were shown to be cytotoxic for untreated SK-N-MC cells. This cytotoxicity was partially inhibited by addition of TRAILR2/Fc fusion protein, indicating that the secreted TRAIL mediates, at least in part, the apoptotic effect displayed by the supernatants of stimulated SK-N-MC cells. We have shown that the presence of IFNgamma is required to allow the sustained expression of IRF1 in SK-N-MC cells stimulated by addition of IFNalpha or TNFalpha suggesting that IRF1 plays a role in the synergistic induction of apoptosis by combinations of cytokines. Furthermore, we have shown that inhibition of NF-kappaB activation contributes to the IFNgamma-mediated sensitization to the apoptotic effect of TNFalpha. To our knowledge, this is the first report showing that interferon/cytokine combinations are able to induce TRAIL gene expression and TRAIL protein synthesis and secretion in Ewing sarcoma-derived cells. We believe that the observations reported here might contribute to the development of alternative new approaches to the treatment of Ewing tumors resistant to conventional therapy.
Abadie
Annie
A
INSERM U365 Institut Curie, Section Recherche, 26, rue D'Ulm, 75 248, Paris Cedex 05, France.
Besançon
Françoise
F
Wietzerbin
Juana
J
D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins; D001483:Base Sequence; D001859:Bone Neoplasms; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D017931:DNA Primers; D005434:Flow Cytometry; D006801:Humans; D007370:Interferon Type I / Q000494:pharmacology; D007371:Interferon-gamma / Q000494:pharmacology*; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012512:Sarcoma, Ewing; D053221:TNF-Related Apoptosis-Inducing Ligand; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000235:genetics* / Q000494:pharmacology*
D051017:Apoptosis Regulatory Proteins; D017931:DNA Primers; D007370:Interferon Type I; D008562:Membrane Glycoproteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma