PCSK1 and melanoma: Our findings led us to conclude that RIPK3 overexpression can promote DL-induced necroptosis independently from RIPK1 activity as previously demonstrated.25, 30 In contrast, IAP antagonist/zVAD/CD95L-induced MLKL phosphorylation in RIPK3-expressing melanomas was partially suppressed by Nec-1 and other RIPK1 inhibitors but fully suppressed by any of the used RIPK3 inhibitors.