Tailoring Vascular‐Immune Homeostasis via Manganese‐DNA Complex‐Armed Immunogenic Extracellular Vesicles for Pancreatic Cancer Immunotherapy

Abstract Harnessing the cGAS‐STING DNA sensing pathway in dendritic cells (DCs) to enhance anti‐tumor immunity in immunosuppressive pancreatic tumors remains a significant challenge. While manganese (Mn 2+ ) enhances cGAS sensitivity to DNA, the precise mechanisms and potential of Mn‐DNA complexes in this process are unclear. Here, this work introduces a strategy to encapsulate Mn‐DNA complexes into DC‐derived immunogenic extracellular vesicle (EV DC @Mn‐DNA) to trigger robust anti‐tumor immunity. This work shows that Mn 2+ induces tumor cell‐DNA transition to Z‐DNA, strengthening cGAS binding and promoting its phase condensation for optimal activation in DCs. Using this newly developed Raft‐Ultra method, this work engineers immunogenic EVs derived from tumor cell lysate‐pulsed DCs, loaded with Mn‐DNA complexes (EV DC @Mn‐DNA). These EVs efficiently deliver Mn‐DNA complexes to DCs, activating the cGAS‐STING pathway both in vitro and in vivo. In animal models, EV DC @Mn‐DNA administration enhances vascular function, as evidenced by increased blood flow and perfusion, improved anti‐PD‐L1 delivery, reduced hypoxia, and elevated endothelial cell‐ICAM1 expression, which facilitates T cell adhesion. This approach expands the intratumoral population of activated DCs and T cells and promotes the formation of larger tertiary lymphoid structures, ultimately suppressing orthotopic pancreatic tumor growth. Overall, this EV DC @Mn‐DNA strategy reprograms intratumoral DCs, restores vascular‐immune homeostasis, and potentiates anti‐tumor immunity in pancreatic cancer.