Legumain Protease-Activated Tuftsin-Functionalized Nanoparticles for Dual-Targeting TAMs and Cancer Chemotherapy

M2 tumor-associated macrophages (TAMs) play a pivotal role in cancer progression and therapy resistance. Inhibition of TAMs is of great significance to reshape the protumor environment to benefit therapeutic outcomes. In this work, we developed a novel TAMs and tumor cells dual-targeting nanoparticle (ATpep-NPs) system for cancer chemotherapy by integrating a docetaxel (DTX)-loaded nanocarrier and a multi-function peptide ATpep, which is composed of a phagocytosis-stimulating peptide-tuftsin (Tpep) fused with a substrate peptide-alanine-alanine-asparagine (AAN) of endoprotease legumain. In vitro protelytic and cellular uptake assays confirmed ATpep-NPs can be responsively activated into Tpep-NPs by cleavage of legumain that is overexpressed in both tumor cells and TAMs, which then promoted tumor cells internalization and TAMs phagocytosis through neuropilin-1/Fc receptor pathways. Due to AAN deactivation effect, ATpep-NPs can effectively decrease the Tpep-induced non-specific uptake by M1-polarized and normal macrophage during systemic circulation. Our results of in vivo experiments demonstrated ATpep-NPs outperformed Tpep-NPs in tumor and TAMs dual-targeting delivery efficiency with markedly enhanced efficacy against both tumor growth inhibition and TAMs depletion. Overall, this study offers a novel approach for development of multitargeted delivery vehicle for improved cancer chemotherapy.