Fig. 5

IFN-γ-mediated inhibition of NK lysis was modulated by proteasome activity. (A) The ovarian cancer cells were treated with gradient concentration of IFN-γ for 24 h. IFN-γ could increase proteasome activity of the tumor cells. (B) Proteasome inhibitor MG-132 had no influences on IFN-γ-induced upregulation of total HLA-E protein. (C) Surface HLA-E expression was reduced with MG-132 treatment. (D) SKOV3 cells transfected with EGFP was observed after being cultured with NKL cells for 4 h. More tumor cells were survived in IFN-γ stimulating group than in control group. MG-132 could reduce the survival rate to abrogate the effect of IFN-γ. The bars = 250 μm. (E) LDH cytotoxicity assay was used to indicate the function of NK lysis. IFN-γ reduced the cytotoxicity of NK cells significantly compared with control and MG-132 treatment groups. ^**P < 0.01. Data shown represented one of three independent experiments