Functional Gadofullerene Nanoparticles Trigger Robust Cancer Immunotherapy Based on Rebuilding an Immunosuppressive Tumor Microenvironment.

Cancer immunotherapy as a novel cancer therapeutic strategy has shown enormous promise. However, the immunosuppressive tumor microenvironment (ITM) is a primary obstacle. Tumor-associated macrophages (TAMs) as a major component of immune cells in a tumor microenvironment are generally polarized to the M2 phenotype that not only accelerates tumor growth but also influences the infiltration of lymphocytes and leads to immunosuppression. Thus, rebuilding ITM by re-educating TAMs and increasing infiltration of lymphocytes is a promising strategy. Herein, gadofullerene (GF-Ala) nanoparticles are demonstrated to reprogram TAMs to M1-like and increase the infiltration of cytotoxic T lymphocytes (CTLs), achieving effective inhibition of tumor growth. Notably, the modulation of ITM by GF-Ala promotes the anticancer efficacy of anti-PD-L1 immune checkpoint inhibitor, achieving superior synergistic treatment. Additionally, GF-Ala nanoparticles can be mostly excreted from the body and cause no obvious toxicity. Together, this study provides an effective immunomodulation strategy using gadofullerene nanoparticles by rebuilding ITM and synergizing immune checkpoint blockade therapy.