Fig. 1

NOS1 blocks IFNα-stimulated gene induction and promotes lung metastasis of melanoma. a A375 cells were stimulated with IFNα (1000 U/ml) for 6 h in the presence or absence of simultaneous GSNO (100 μM). The mRNA expression of ISGs was analyzed by RT-PCR. b Control/NOS1 (A375) cells were treated with IFNα (1000 U/ml) for 6 h, followed by RT-PCR analysis. c, d Similar to a, but c N-PLA (100 μM), d L-NAME (1 mM) was used. e Control/NOS1 (A375) cells were cotransfected with pISRE-luc and Renilla-luc reporter plasmids for 24 h, treated with IFNα (1000 U/ml) for 6 h, and analyzed by luciferase assay. f Control/NOS1 (A375) cells were incubated with IFNα (1000 U/ml) for the indicated times, and western blotting was used to detect the protein expression of IRF7. g, h The effect of Over-NOS1 on the expression of IFNα-ISGs in g B16 cells and h tumor tissues was detected by RT-PCR. i Representative images of lung tissue and lung sections stained with H&E from each group are shown. j, k The j tumor nodules and k lung weight of each group (n = 4). l Mice were sacrificed individually upon signs of metastatic distress and lung metastasis confirmed via histology. m Long rank analysis of mouse survival rates (n = 8). ns, not significant; *p < 0.05; **p < 0.01; ***p < 0.001; and ****p < 0.0001