RVH-421

Targeting ZBP1-Mediated PANoptosis Induces Melanoma Cell Death

Cancer is characterized by resistance to programmed cell death (PCD). However, the therapeutic potential of particular compounds is often obscured by redundancy and crosstalk amongst PCD pathways. PANoptosis, an innate immune-driven inflammatory cell death mechanism that integrates elements of pyroptosis, apoptosis and necroptosis, has emerged as a critical determinant of cancer cell fate. Mall et al. systematically identified the important predictive influence of PANoptosis in several malignancies using a computational methodology. Interestingly, increased expression of critical PANoptosis molecules was connected with better patient survival in skin cutaneous melanoma (SKCM), indicating that induction of PANoptosis may be a promising treatment method.

Z-DNA binding protein 1 (ZBP1) is the primary regulator of PANoptosis. In mouse models, ZBP1 binds nucleic acids via its Zα domain and interacts with the RHIM domain of RIPK3 to induce cell death. ZBP1 is known to trigger PANoptosis by activating NLRP3 inflammasome, caspase-8, caspase-7, GSDMD and MLKL. Given the positive correlation of ZBP1 with survival in SKCM, they anticipated that targeting ZBP1 could cause melanoma cell death. Two human melanoma cell lines, SK-MEL-5 and RVH-421, were selected for their variety in donor sex, tumor type and anatomical origin, and their high PANoptosis scores measured by ssGSEA. Nuclear export inhibitors KPT-335 or leptomycin B (LMB) plus interferon-gamma (IFN-γ) significantly boosted cell death relative to monotherapies or controls (Fig. 1A-D). Combination therapy induced upregulation of ZBP1 and activation of PANoptotic executioner molecules including caspase-1, GSDMD, GSDME, caspase-8, caspase-3 and caspase-7 in RVH-421 cells (Fig. 2).

These data suggest that pharmacological upregulation of ZBP1 expression initiates PANoptosis and strongly induces melanoma cell death. This validates the therapeutic importance of PANoptosis-related compounds found with computational frameworks and offers a path to next-generation cancer immunotherapies.