Hydrogel/nanoparticles-mediated cooperative combination of antiangiogenesis and immunotherapy

Vascular abnormalities are directly related to the tumor immunosuppressive microenvironment, which is an important obstacle to effective immunotherapy. The combination of antiangiogenesis therapy and immunotherapy may promote a mutually reinforcing cycle of immune reprogramming and vascular normalization to increase the effectiveness of immunotherapy. Herein, a hydrogel/nanosystem-mediated antiangiogenesis combined immunotherapy strategy was used to regulate the tumor microenvironment by the controlled release of apatinib, CD47 antibody (aCD47), and CpG. The combination of hydrogel with nanoparticles protected drug activity and maintained a long-term slow release of the drug for maximum synergistic efficacy. Apatinib promotes vascular normalization in tumors and enhances the efficacy of aCD47-based immunotherapy. The addition of immunoadjuvant CpG further enhanced antigen presentation and stimulated the anti-tumor activity of macrophages to strengthen the efficacy of antiangiogenesis combined immunotherapy. The main effector immune cells, including CD4⁺ T, CD8⁺ T, NK, and activity DCs, were significantly increased after combination treatment, while the proportion of various immunosuppressive cells decreased significantly, especially MDSCs and M2-polarized macrophages. Based on an effective systemic immune response, the hydrogel/nanoparticle-mediated cooperative combination of antiangiogenesis and immunotherapy enhanced the synergistic effect for primary tumors and prevented metastasis for tumor treatment. The biomaterial-mediated antiangiogenesis combined immunotherapy strategy is a promising strategy for effective immunotherapy. STATEMENT OF SIGNIFICANCE: Relieving immunosuppression of the tumor microenvironment is the key to restoring and rebuilding the normal anti-tumor immune defense of the body. Vascular abnormalities are directly related to the tumor immunosuppressive microenvironment, which is an important obstacle to effective immunotherapy. The combination of antiangiogenesis and immunotherapy may promote a mutually reinforcing cycle of immune reprogramming and vascular normalization to increase the effectiveness of immunotherapy. For the combination of antiangiogenesis and immunotherapy, effective drug delivery to overcome local immune tolerance and regulate the tumor microenvironment to increase therapeutic effects is an important issue. The hydrogel/nanomaterial composite system constructs a dual sustained-release system to achieve step-by-step controlled release of antiangiogenic drugs and immune immunotherapy drugs to promote cooperative combination therapy.