The cancer immunotherapeutic effect of a carboxymethylated β-d-glucan (CMPTR)/iron oxide nanoparticles (IONPs) system (CMPTR/IONPs) were investigated by using cell culture of bone marrow-derived macrophages (BMDMs) and B16F10 melanoma skin cancer-bearing mouse model. When compared with that of control group, CMPTR/IONPs-treated M2-like BMDMs exhibited upregulated M1 biomarkers expression, significantly inhibited the migration of B16F10 cancer cells (p < 0.05), and had the highest apoptotic percentage of B16F10 cancer cells (80.39 ± 8.73 %) in co-culture system. Intratumoral administration of CMPTR/IONPs significantly (p < 0.05) suppressed tumor growth (46.58 % based on tumor weight) in mice and enhanced the M1/M2 ratio from 0.40 ± 0.09 (control group) to 6.64 ± 1.61 in tumor associated macrophages (TAMs) which was higher than that of in CMPTR (1.27 ± 0.38), IONPs (1.38 ± 0.17). CMPTR/IONPs treatment also promoted apoptosis in cancer cells and increased the infiltration of CD4 and CD8 T-lymphocytes in tumor tissues. These results could be due to the combined effects of CMPTR and IONPs in the CMPTR/IONPs system, possibly mediated by the activation of NF-κB and IRF5 pathways for inducing M1 macrophages polarization and had potential cancer immunotherapeutic applications.
Keywords: Cancer immunotherapeutic effect; Carboxymethylated β-d-glucan; Iron oxide nanoparticles; Targeting delivery; Tumor-associated macrophages.
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