Nanoparticle-Loaded Polarized-Macrophages for Enhanced Tumor Targeting and Cell-Chemotherapy

Cell therapy is a promising strategy for cancer therapy. However, its therapeutic efficiency remains limited due to the complex and immunosuppressive nature of tumor microenvironments. In this study, the "cell-chemotherapy" strategy was presented to enhance antitumor efficacy. M1-type macrophages, which are therapeutic immune cells with both of immunotherapeutic ability and targeting ability, carried sorafenib (SF)-loaded lipid nanoparticles (M1/SLNPs) were developed. M1-type macrophages were used both as therapeutic tool to provide immunotherapy and as delivery vessel to target deliver SF to tumor tissues for chemotherapy simultaneously. M1-type macrophages were obtained by polarizing macrophages using lipopolysaccharide, and M1/SLNPs were obtained by incubating M1-type macrophages with SLNP. Tumor accumulation of M1/SLNP was increased compared with SLNP (p < 0.01), which proved M1/SLNP could enhance tumor targeting of SF. An increased ratio of M1-type macrophages to M2-type macrophages, and the CD3⁺CD4⁺ T cells and CD3⁺CD8⁺ T cell quantities in tumor tissues after treatment with M1/SLNP indicated M1/SLNP could relieve the immunosuppressive tumor microenvironments. The tumor volumes in the M1/SLNP group were significantly smaller than those in the SLNP group (p < 0.01), indicating M1/SLNP exhibited enhanced antitumor efficacy. Consequently, M1/SLNP showed great potential as a novel cell-chemotherapeutic strategy combining both cell therapy and targeting chemotherapy.