Remodeling Tumor‐Associated Neutrophils to Enhance Dendritic Cell‐Based HCC Neoantigen Nano‐Vaccine Efficiency

Abstract Hepatocellular carcinoma (HCC) commonly emerges in an immunologically “cold” state, thereafter protects it away from cytolytic attack by tumor‐infiltrating lymphocytes, resulting in poor response to immunotherapy. Herein, an acidic/photo‐sensitive dendritic cell (DCs)‐based neoantigen nano‐vaccine has been explored to convert tumor immune “cold” state into “hot”, and remodel tumor‐associated neutrophils to potentiate anticancer immune response for enhancing immunotherapy efficiency. The nano‐vaccine is constructed by SiPCCl 2 ‐hybridized mesoporous silica with coordination of Fe(III)‐captopril, and coating with exfoliated membrane of matured DCs by H22‐specific neoantigen stimulation. The nano‐vaccines actively target H22 tumors and induce immunological cell death to boost tumor‐associated antigen release by the generation of excess 1 O 2 through photodynamic therapy, which act as in situ tumor vaccination to strengthen antitumor T‐cell response against primary H22 tumor growth. Interestingly, the nano‐vaccines are also home to lymph nodes to directly induce the activation and proliferation of neoantigen‐specific T cells to suppress the primary/distal tumor growth. Moreover, the acidic‐triggered captopril release in tumor microenvironment can polarize the protumoral N2 phenotype neutrophils to antitumor N1 phenotype for improving the immune effects to achieve complete tumor regression (83%) in H22‐bearing mice and prolong the survival time. This work provides an alternative approach for developing novel HCC immunotherapy strategies.