Also, a 1 h pre-treatment of 1205Lu and Dauv-1 melanoma cells with the proteasome inhibitors MG132 and ALLN strongly inhibited SMAD3/4-specific transcriptional response induced by TGF-β in transient cell transfection experiments with (CAGA)9-MLP-luc (Figures 3B and 3C, respectively). This evidence concerns the gene TGFB1 and melanoma.