Dual‐Targeted Engineered Bacterial Outer Membrane Vesicles for Hepatocellular Carcinoma Immunotherapy

Abstract

Cluster of differentiation 47 (CD47) is an important innate immune checkpoint that empowers tumors to send “don't eat me” signals, leading to immune escape. CD47 monoclonal antibodies have achieved remarkable therapeutic success in hematological malignancies. However, their efficacy in solid tumors is limited, mainly because of immunosuppression in the tumor microenvironment. In addition, hematotoxicity severely hinders the clinical translation of CD47 antibodies. Here, a novel genetically programmed nanovesicle, OMV‐CD47/GPC3, is generated for hepatocellular carcinoma (HCC) immunotherapy by fusing anti‐CD47 nanobodies and anti‐GPC3 scFv onto bacterial outer membrane vesicles (OMVs). Following intravenous administration, dual‐targeted OMV‐CD47/GPC3 specifically recognized tumor cells expressing both CD47 and GPC3, thereby actively targeting and accumulating at the orthotopic HCC tumor site without hematotoxicity. OMV‐CD47/GPC3 potently blocked tumor CD47 and promoted macrophage phagocytosis. More importantly, immunogenic OMV‐CD47/GPC3 can effectively remodel the tumor immune microenvironment of orthotopic HCC, especially reprogram tumor‐associated macrophages (TAMs) to the M1‐phenotype and promote dendritic cell maturation, synergistically inducing a robust CD8+ T cell‐mediated anti‐tumor immune response. With the two‐pronged approach of immune checkpoint inhibition and immune activation, engineered OMV‐CD47/GPC3 significantly suppressed orthotopic HCC growth and prevented tumor recurrence and metastasis, thus providing a promising strategy for HCC immunotherapy.