HOIP limits anti-tumor immunity by protecting against combined TNF and IFN-gamma-induced apoptosis

The success of cancer immunotherapy is limited to a subset of patients, highlighting the need to identify the processes by which tumors evade immunity. Using CRISPR/Cas9 screening, we reveal that melanoma cells lacking HOIP, the catalytic subunit of LUBAC, are highly susceptible to both NK and CD8(+) T-cell-mediated killing. We demonstrate that HOIP-deficient tumor cells exhibit increased sensitivity to the combined effect of the inflammatory cytokines, TNF and IFN-gamma, released by NK and CD8(+) T cells upon target recognition. Both genetic deletion and pharmacological inhibition of HOIP augment tumor cell sensitivity to combined TNF and IFN-gamma. Together, we unveil a protective regulatory axis, involving HOIP, which limits a transcription-dependent form of cell death that engages both intrinsic and extrinsic apoptotic machinery upon exposure to TNF and IFN-gamma. Our findings highlight HOIP inhibition as a potential strategy to harness and enhance the killing capacity of TNF and IFN-gamma during immunotherapy.