Polymeric nanocarrier via metabolism regulation mediates immunogenic cell death with spatiotemporal orchestration for cancer immunotherapy

The limited efficacy of cancer immunotherapy occurs due to the lack of spatiotemporal orchestration of adaptive immune response stimulation and immunosuppressive tumor microenvironment modulation. Herein, we report a nanoplatform fabricated using a pH-sensitive triblock copolymer synthesized by reversible addition-fragmentation chain transfer polymerization enabling in situ tumor vaccination and tumor-associated macrophages (TAMs) polarization. The nanocarrier itself can induce melanoma immunogenic cell death (ICD) via tertiary amines and thioethers concentrating on mitochondria to regulate metabolism in triggering endoplasmic reticulum stress and upregulating gasdermin D for pyroptosis as well as some features of ferroptosis and apoptosis. After the addition of ligand cyclic arginine-glycine-aspartic acid (cRGD) and mannose, the mixed nanocarrier with immune adjuvant resiquimod encapsulation can target B16F10 cells for in situ tumor vaccination and TAMs for M1 phenotype polarization. In vivo studies indicate that the mixed targeting nanoplatform elicits tumor ICD, dendritic cell maturation, TAM polarization, and cytotoxic T lymphocyte infiltration and inhibits melanoma volume growth. In combination with immune checkpoint blockade, the survival time of mice is markedly prolonged. This study provides a strategy for utilizing immunoactive materials in the innate and adaptive immune responses to augment cancer therapy. Cancer immunotherapy leans on the effective activation on immune response within tumors and surrounding immunosuppressive microenvironment. Here, the authors report a triblock copolymeric nanocarrier encapsulating Resiquimod for B16F10 cell-targeting, which enables in situ tumor vaccination and tumor-associated macrophages polarization.