Tumors Cells with Mismatch Repair Deficiency Induce Hyperactivation of Pyroptosis Resistant to Cell Membrane Damage but Are More Sensitive to Co-Treatment of IFN-γ and TNF-α to PANoptosis

Hypermutated neoantigens in cancers with DNA mismatch repair deficiency (dMMR) are prerequisites for favorable clinical responses to immune-checkpoint blockade (ICB) therapy. However, TMB is not significantly associated with favorable prognosis from Preclinical and clinical studies. It implies that except for TMB, other mechanisms should be needed to contribute to successful cancer immunotherapy. We found that the hyperactivation of PANoptotic effective molecules in dMMR tumor cells caused cell membrane damage, induced ESCRT-mediated membrane repair, and protected tumor cells from the damage caused by Triton X-100, while DNA mismatch repair proficient (pMMR) tumor cells were sensitive to Triton X-100 mediating cell membrane damage due to the lack of ESCRT-mediated membrane repair. There was hyperactivation of GSDMD, GSDME, and p-MLKL in dMMR tumor cells. Co-treatment of IFN-gamma and TNF-alpha induced rapid death of dMMR tumor cells by inducing PANoptosis including pyroptosis, apoptosis, and no necrosis. pMMR tumor cells had defects in the PANoptosis pathway and were resistant to co-treatment of IFN-gamma and TNF-alpha. In conclusion, we can activate immune cells to release IFN-gamma and TNF-alpha to overcome resistance to ICB treatment.