RIPK3 and cancer: To specify the canonical apoptosis pathway, receptor-interacting kinase 3 (RIPK3)-negative cancer cell lines, such as HeLa, MDA-MB-231, and U2OS cells, were selected (Supplementary Fig. S1a) and stimulated with TNF-α in the presence of cycloheximide, which inhibits the synthesis of NF-κB target proteins25.