Nanoconjugate Strategy Integrating Immunogenic Cell Death Induction and Innate Immune Activation for Potent Anti‐Cancer Immunity

ABSTRACT In vivo immune modulation can potentially benefit broader cancer patients. Efficient cross‐priming of anti‐tumor T cells requires “three‐signal” dendritic cells (DCs) that simultaneously integrate antigenic, co‐stimulatory, and migratory programs, which remains a major challenge. Here, we developed a carrier‐free peptide–cyclic dinucleotide (CDN) nanoconjugate (PCN) that co‐activates immunogenic cell death (ICD) in tumors and stimulator of interferon genes (STING) signaling in DCs. Library screening identified ICD‐inducing peptides enriched in hydrophobic and cationic residues that promote self‐assembly, cell penetration, and ICD potency. Mechanistic studies revealed peptides can trigger overlapping pyroptosis, necroptosis, and apoptosis, with lysosomal damage and cathepsin release as dominant upstream drivers. PCN promoted tumor‐antigen release and facilitated cytosolic CDN delivery for robust STING activation. This dual functionality induced early cytokine and chemokine responses and generated cDC1‐enriched “three‐signal” migratory DCs trafficking from tumors to draining lymph nodes, resulting in enhanced antigen‐specific CD8 + T‐cell activation and memory formation. PCN also broadly reprogrammed the tumor microenvironment toward anti‐tumor immunity. In preclinical models, PCN induced complete tumor rejection in 70% of B16‐F10‐ or CT26‐bearing mice and provided durable protection against tumor rechallenge when combined with α ‐PD‐1.