Reduced IFN-stimulated gene expression in melanoma cells over-expressing SOCS1 and SOCS3. Transcript levels of the IFN-α-responsive genes (a) ISG-15, (b) OAS-1, and (c) IFIT2 were measured following a 4 hour stimulation of SOCS1- and SOCS3-over-expressing cell lines with IFN-α (104 U/mL) by Real Time PCR. (d) Transcript levels of the IFN-γ-responsive gene IRF1 was also measured in the cell lines following a 4 hour stimulation with 1 ng/mL IFN-γ. All data were normalized to β-actin (housekeeping gene) and expressed relative to PBS-treated cells. * Denotes p < 0.05 as compared to empty vector transduced cells.