2004 Volume 50 Issue 11 Pages 629-635
Fas is widely expressed on the cell surface of many normal and neoplastic cells and induces apoptotic cell death in the presence of Fas ligand (FasL) or Fas-agonistic antibody CH11 (Fas-mediated apoptosis) Cancer cells constitutively expressing Fas are generally resistant to Fas-mediatedapoptosis. Recently, it has been reported that interferon-γ(IFN-γ) enhances Fas-mediated apoptosis. An oral squamous cell carcinoma cell line, NA, also constitutively expresses Fas on the plasma membrane and shows low susceptibility to Fas-agonistic antibody-induced apoptosis. This study was conducted to examine the effects of IFN-γ on Fas-mediated apoptosis, the expression of Fas and FasL, and the production of soluble Fas (sFas) in NA cells. The results revealed that a Fas-agonistic antibody, CH11, induced apoptosis of NA cells and IFN-γ enhanced susceptibility of NA cells to CH11-induced apoptosis. Further more, IFN-γ up-regulated Fas expression on NA cells without affecting the expression of FasL. A slight decrease in sFas expression was induced by treatment with IFN-γ. These results suggest that IFN-γ may enhance the susceptibility of NA cells to Fas-mediated apoptosis through the up-regulation of Fas.
