A baicalein and oxaliplatin co-loaded nano-delivery system for dual gasdermin-mediated pyroptosis in pancreatic ductal adenocarcinoma.

Abstract

e16456 Background: Pancreatic ductal adenocarcinoma (PDAC) features a highly immunosuppressive tumor microenvironment (TME). Inducing pyroptosis is a promising strategy to reverse this “cold” TME, but achieving synergistic activation of dual gasdermin (GSDMD/GSDME) pathways with efficient tumor-targeted delivery remains challenging. Methods: We constructed a nano-delivery system co-loading baicalein and oxaliplatin (B/O@NPs). Its mechanisms and anti-tumor efficacy were evaluated in PDAC cell lines (PANC02, MIAPaCa-2), 3D spheroids, immunocompetent subcutaneous models, and patient-derived xenograft (PDX) models. Techniques included confocal microscopy, flow cytometry, western blot, ELISA, RNA-seq, and immunofluorescence. Results: BONPs demonstrated efficient tumor targeting and penetration in vivo. Mechanistically, baicalein inhibited NF-κB nuclear translocation, leading to mitochondrial dysfunction and reactive oxygen species (ROS) burst, which activated the NLRP3/caspase-1/GSDMD pathway. Concurrently, oxaliplatin triggered caspase-3-mediated cleavage of GSDME. This dual activation resulted in synergistic pyroptosis, confirmed by increased LDH release, IL-1β/IL-18 secretion, and cleavage of GSDMD/GSDME. Pyroptosis induced robust immunogenic cell death (ICD), evidenced by calreticulin exposure, HMGB1 and ATP release. In vitro, BONPs-treated tumor cells promoted dendritic cell (DC) maturation. In vivo, B/O@NPstreatment significantly inhibited tumor growth in both subcutaneous and PDX models. Crucially, it remodeled the TME by increasing infiltration of mature DCs (43.2% vs. PBS), CD8+ T cells (49.2% vs. 1.1% in PBS), and the M1/M2 macrophage ratio (9.51 vs. 0.89 in PBS), while also generating effector memory T cells in the spleen. BONPs treatment mitigated the systemic weight loss associated with free oxaliplatin. Conclusions: The B/O@NPs system effectively co-activates dual gasdermin-mediated pyroptosis, leading to potent ICD and remodeling of the immunosuppressive PDAC TME into an immunologically active state, accompanied by favorable safety profile. This nanoplatform presents a novel combinatorial strategy for PDAC treatment.