Cellular FLICE-like inhibitory protein (cFLIP)

Cellular FLICE-like inhibitory protein (cFLIP), encoded by the CFLAR gene, is a master regulator of the extrinsic apoptosis pathway and a key factor in therapeutic resistance. Structurally, cFLIP is a protease-dead homolog of procaspase-8 that contains two death effector domains (DEDs), allowing it to competitively bind to the adaptor protein FADD within the death-inducing signaling complex (DISC) (Safa AR, 2012). By preventing the recruitment and full activation of initiator caspases-8 and -10, cFLIP effectively blocks the downstream apoptotic cascade (UniProt CFLAR). It is frequently overexpressed in a wide range of human cancers, including breast, colon, and lung malignancies, where it facilitates immune evasion and resistance to death receptor ligands like TRAIL and various chemotherapeutic agents (Safa AR, et al., 2019). Beyond its anti-apoptotic role, cFLIP also modulates other cell death modalities such as necroptosis and autophagy, and acts as a scaffold to activate pro-survival signaling pathways including NF-κB, ERK, and Akt. Pharmacological strategies targeting cFLIP aim to downregulate its expression or disrupt its interaction at the DISC to sensitize tumor cells to apoptosis. However, therapeutic development must account for its physiological roles in heart development and T-cell homeostasis to avoid systemic toxicity.

Other names

CFLARCASP8 and FADD-like apoptosis regulatorFLAME-1I-FLICECASPERCASHCLARPMRITUsurpin

cFLIP inhibits the extrinsic apoptosis pathway by competitively binding to the FADD adaptor protein and procaspase-8/10 at the death-inducing signaling complex (DISC), thereby preventing the proteolytic activation of initiator caspases. It also functions as a molecular switch between apoptosis, necroptosis, and autophagy, and can activate pro-survival pathways such as NF-κB and ERK.