Functional Nucleic Acids Mediated Tumor-Associated Macrophages Reprogramming And Restores Antitumor Immunity

Tumor-associated macrophages（TAMs）are important immune effector cells in the tumor microenvironment and have a high degree of plasticity,which leads to macrophages to polarize into different phenotypes under different factors and exerts different functions.Among them,M1macrophages can directly phagocytose tumor cells,secrete pro-inflammatory cytokines and chemokines to activate immune responses,and participate in positive immune responses.On the contrary,M2macrophages secrete immunosuppressive cytokines,inhibit adaptive immunity response and promote tumor progression.During the occurrence and development of tumors,TAMs gradually polarize into M2macrophages,which promotes tumor growth and metastasis.Clinical studies have also shown that the infiltration of TAMs is related to poor prognosis in the tumor microenvironment.Therefore,TAMs have emerged as an attractive potential therapeutic target for tumor immunotherapy.In recent years,functional nucleic acids have been widely applied in tumor diagnosis and treatment due to their good biocompatibility,ease of synthesis and diversity of chemical modifications.In this paper,two strategies are developed to regulate TAMs in tumor microenvironment through functional nucleic acids to promote anti-tumor immunotherapy.which mainly include the following main contents:1.Self-assembled Tetrahedral Framework Nucleic Acid Mediated Tumor-associated Macrophages Reprogramming and Restores Antitumor ImmunityDNA nanostructure has been widely developed and applied as a nano-carrier with excellent loading performance.In this section,we developed a facile strategy of linking si RNAs and Cp G to a tetrahedral framework nucleic acid（t FNA）by simple base complementation pairs to combine delivery to TAMs cells.Specifically,the t FNA with controllable loading density can simultaneously deliver si RNAs and Cp G into cells.The t FNA composed of Cp G and si RNA showed a higher stability and an enhanced cellular uptake efficiency.Moreover,the Cp G-si RNA-t FNA effectively reprogrammed TAMs toward M1 phenotype polarization with increased pro-inflammatory cytokines secretion and NF-κB signal pathway activation,which triggering dramatical antitumor immune responses.Additionally,the Cp G-si RNA-t FNA effectively reprogrammed TAMs toward M1 phenotype polarization in tumor microenvironment,which exhibited superior antitumor efficacy in vivo.2.Dual Aptamers Engineering M1 Macrophage with Enhanced Specific Targeting and Checkpoint Blocking for Breast Cancer ImmunotherapyChimeric antigen receptor T cells（CAR-T）therapy has faced a series of challenges and shown very little efficacy in solid tumors to date.Although genetically engineered macrophages have achieved the definite therapeutic effect in solid tumors,heterogeneous expression of engineered proteins and potential for toxicity limit further applications.Herein,we proposed a nongenetic and simple macrophage cell engineering strategy.Azido-labeled M1 macrophages were obtained by Ac₄Man NAz and LPS treatment.The AS1411 and PD-L1 aptamers were modified to the surface of cytomembrane by efficiently and stably bind of azide groups and dibenzocycloctyl（DBCO）modified aptamers.The aptamers-engineered M1 macrophage（Ap En-M1）showed enhanced active targeting ability for tumor cells in vitro,promoting the apoptosis of tumor cells.Moreover,Ap En-M1 exhibited superior antitumor efficacy in breast cancer xenograft mouse model and lung metastasis mouse model of breast cancer.Interestingly,the Ap En-M1 could reprogram the immunity microenvironment by increasing the T cells infiltration and enhancing T cells activity in tumor region.