Mitochondrial permeabilization engages NF-κB-dependent anti-tumour activity under caspase deficiency

Giampazolias E, Zunino B, Dhayade S, Bock F, Cloix C, Cao K, Roca A, Lopez J, Ichim G, Proïcs E, Rubio-Patiño C, Fort L, Yatim N, Woodham E, Orozco S, Taraborrelli L, Peltzer N, Lecis D, Machesky L, Walczak H, Albert ML, Milling S, Oberst A, Ricci JE, Ryan KM, Blyth K, Tait SWG

Nat. Cell Biol. 2017 Sep;19(9):1116-1129

Abstract

PMID: 28846096

Apoptosis represents a key anti-cancer therapeutic effector mechanism. During apoptosis, mitochondrial outer membrane permeabilization (MOMP) typically kills cells even in the absence of caspase activity. Caspase activity can also have a variety of unwanted consequences that include DNA damage. We therefore investigated whether MOMP-induced caspase-independent cell death (CICD) might be a better way to kill cancer cells. We find that cells undergoing CICD display potent pro-inflammatory effects relative to apoptosis. Underlying this, MOMP was found to stimulate NF-κB activity through the downregulation of inhibitor of apoptosis proteins. Strikingly, engagement of CICD displays potent anti-tumorigenic effects, often promoting complete tumour regression in a manner dependent on intact immunity. Our data demonstrate that by activating NF-κB, MOMP can exert additional signalling functions besides triggering cell death. Moreover, they support a rationale for engaging caspase-independent cell death in cell-killing anti-cancer therapies.