摘要Macrophages are important antigen-presenting cells to combat tumor via both innate and adaptive immunity,while they are programmed to M2 phenotype in established tumors and instead promote cancer development and metastasis.Here,we develop a nanomedicine that can re-educate M2 polarized macrophages to restore their anti-tumor activities.The nanomedicine has a core-shell structure to co-load IPI549,a PI3Ky inhibitor,and CpG,a Toll-like receptor 9 agonist.Specifically,the hydrophobic IPI549 is self-assembled into a pure drug nano-core,while MOF shell layer is coated for CpG encapsulation,achieving extra-high total drugs loading of 44％.Such nanosystem could facilitate intracellular delivery of the payloads but without any cytotoxicity,displaying excellent biocompatibility.After entering macrophages,the released IPI549 and CpG exert a synergistic effect to switch macrophages from M2 to M1 phenotype,which enables anti-tumor activities via directly engulfing tumor cells or excreting tumor killing cytokines.Moreover,tumor antigens released from the dying tumor cells could be effectively presented by the re-educated macrophages owing to the up-regulation of various antigen presenting mediators,resulting in infiltration and activation of cytotoxic T lymphocytes.As a result,the nanosystem triggers a robust anti-tumor immune response in combination with PD-L1 antibody to inhibit tumor growth and metastasis.This work provides a non-cytotoxic nanomedicine to modulate tumor immune microenvironment by reprograming macrophages.