DAPK3-DCAF1 Pathway Regulates ZBP1 Stability in Ovarian Cancer

Background: Z-DNA binding protein 1 (ZBP1) is an interferons (IFN)-stimulated cytosolic sensor of Z-nucleic acids (Z-NA) that regulates PANoptosis (pyroptosis, apoptosis, and/or necroptosis) and thereby drives potent anti-tumor immune responses. However, the mechanisms controlling ZBP1 protein stability in tumors—and whether they can be therapeutically manipulated to induce ICD—remain unclear. We sought to define regulatory pathways that govern ZBP1 abundance in ovarian cancer and to test strategies that exploit ZBP1 activation for antitumor therapy. Methods & Results: Here we demonstrate that the reduced ZBP1 expression in ovarian cancer and correlated with poorer survival. Type I IFN (IFN-β) rapidly increased ZBP1 levels by inhibiting its proteasome-dependent ubiquitination. Proximity labeling and biochemical assays identified DCAF1 as a key interactor that mediates ZBP1 ubiquitination and degradation. Furthermore, IP-MS and LC-MS/MS identified DAPK3 as an IFN-induced DCAF1 kinase, which phosphorylates DCAF1-pS1328 to promote its turnover, thereby stabilizing ZBP1. Genetic ablation of DCAF1 impaired tumor cell proliferation in vitro, reduced tumor burden and promoted anti-tumor immunity in vivo. Pharmacological targeting of this pathway using the DCAF1 inhibitor B32B3 and—when combined with the Z-NA activator CBL0137—effectively reactivated ZBP1 signaling, promoted PANoptosis, and enhanced antitumor immunity, thereby suppressing tumor growth in two chemotherapy-resistant ovarian cancer patient-derived xenograft (PDX) models and providing a promising therapeutic strategy for refractory malignancies. Conclusion: Overall, this study delineates a novel DAPK3-DCAF1 signaling axis that governs ZBP1 stability, unveiling an integrated regulatory framework that connects interferon signaling, post-translational modification, and immunogenic cell death. Combining DCAF1 blockade with Z-NA activation elicits ZBP1-mediated PANoptosis and augments anti-tumor immunity, representing a promising therapeutic approach for refractory ovarian cancer. Citation Format: Zhiqi Liao, Linghui Wang, Wenjian Gong, Ziyan Zhang, Gordon B. Mills, Ding Ma, Guangnian Zhao, Qinglei Gao, Yong Fang. DAPK3-DCAF1 pathway regulates ZBP1 protein stability to orchestrate innate immune responses and PANoptosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 7462.