RREB1 and melanoma: Additionally, imidazo-pyrazole derivative Ib (Figure 1) showed low micromolar IC50 values against the skin melanoma SKMEL-28 cell line [22] and proteomics studies evidenced its ability to downregulate Ras-responsive element binding protein 1 (RREB1), a crucial molecular target in SKMEL-28 melanoma cells [23].