Macrophage-centered therapy strategies: A promising weapon in cancer immunotherapy

Macrophages are critical phagocytes in the immune system, and tumor-infiltrating macrophages can substantially influence the efficacy and prognosis of immunotherapy. Therefore, macrophages may serve as therapeutic targets for modulating the tumor immune microenvironment. Macrophage-based drug delivery systems have been extensively evaluated owing to their excellent biocompatibility, long half-life, and inherent ability to migrate and accumulate at sites of inflammation, such as tumors. Live macrophages and their membrane coatings contain abundant receptor proteins that facilitate payload transport across physiological barriers. In this review, we discuss strategies that utilize macrophages as targets and delivery carriers for cancer immunotherapy. Here, we summarize the different macrophage phenotypes, tumor-associated macrophage-targeting strategies, and biomimetic delivery carriers derived from macrophages used in immunotherapy. Overall, macrophage-centered strategies for cancer therapy hold considerable promise for clinical applications. Therapeutic strategies targeting TAMs are regarded as one of the most promising research strategies against tumor. At present, strategies for targeting TAM mainly include the inhibition of “don't eat me” signaling at phagocytic checkpoints, inhibition of macrophage recruitment, depletion of TAMs and reprograming TAMs in TME.