RIPK1 and melanoma: RIP1 silencing did not cause any further reduction in the viability of Mel-CV.S and Mel-RMu.S cell transduced with a non-degradable mutant of IκBα (IκBαS32AS36A) (Fig. 3h, i), which diminished NF-κB activity13, confirming the role of NF-κB in RIP1-mediated protection of melanoma cells from killing by PLX4720.