Anti-hepatoma immunotherapy of Pholiota adiposa polysaccharide-coated selenium nanoparticles by reversing M2-like tumor-associated macrophage polarization.

Targeting macrophages to regulate the tumor microenvironment is a promising strategy for treating cancer. This study developed a stable nano drug (PAP-SeNPs) using Se nanoparticles (SeNPs) and the Pholiota adiposa polysaccharide component (PAP-1a) and reported their physical stability, M2-like macrophages targeting efficacy and anti-hepatoma immunotherapy potential, as well as their molecular mechanisms. Furthermore, the zero-valent and well-dispersed spherical PAP-SeNPs were also successfully synthesized with an average size of 55.84 nm and a negative ζ-potential of -51.45 mV. Moreover, it was observed that the prepared PAP-SeNPs were stable for 28 days at 4 °C. Intravital imaging highlighted that PAP-SeNPs had the dual effect of targeting desirable immune organs and tumors. In vitro analyses showed that the PAP-SeNPs polarized M2-like macrophages towards the M1 phenotype to induce hepatoma cell death, triggered by the time-dependent lysosomal endocytosis in macrophages. Mechanistically, PAP-SeNPs significantly activated the Tlr4/Myd88/NF-κB axis to transform tumor-promoting macrophages into tumor-inhibiting macrophages and successfully initiated antitumor immunotherapy. Furthermore, PAP-SeNPs also enhanced CD3CD4 T cells and CD3CD8 T cells, thereby further stimulating anti-hepatoma immune responses. These results suggest that the developed PAP-SeNPs is a promising immunostimulant that can assist hepatoma therapy.