Macrophage Membrane-Camouflaged shRNA and Doxorubicin: A pH-Dependent Release System for Melanoma Chemo-Immunotherapy

Improving the efficacy of melanoma treatment remains an important global challenge. Here, we combined chemotherapy with protein tyrosine phosphatase nonreceptor type 2(Ptpn2) based immunotherapy in an effort to address this challenge. Short-hairpin RNA (shRNA) targeting Ptpn2 was coencapsulated with doxorubicin (DOX) in the cell membrane of M1 macrophages (M1HD@RPR). The prepared nanoparticles (NPs) were effectively phagocytosed by B16F10 cells and M1 macrophages, but not by M0 macrophages. Hence, NP evasion from the reticuloendothelial system (RES) was improved and NP enrichment in tumor sites increased. M1HD@RPR can directly kill tumor cells and stimulate immunogenic cell death (ICD) by DOX and downregulate Ptpn2. It can promote M1 macrophage polarization and dendritic cell maturation and increase the proportion of CD8⁺ T cells. M1HD@RPR killed and inhibited the growth of primary melanoma and lung metastatic tumor cells without harming the surrounding tissue. These findings establish M1HD@RPR as a safe multifunctional nanoparticle capable of effectively combining chemotherapy and gene immunotherapies against melanoma.