CCL9/CCR1 axis-driven chemotactic nanovesicles for attenuating metastasis of SMAD4-deficient colorectal cancer by trapping TGF-.

SMAD4 deficiency in colorectal cancer (CRC) is highly correlated with liver metastasis and high mortality, yet there are few effective precision therapies available. Here, we show that CCR1-granulocytic myeloid-derived suppressor cells (G-MDSCs) are highly infiltrated in SMAD4-deficient CRC CCL15/CCR1 and CCL9/CCR1 axis in clinical specimens and mouse models, respectively. The excessive TGF-, secreted by tumor-infiltrated CCR1-G-MDSCs, suppresses the immune response of cytotoxic T lymphocytes (CTLs), thus facilitating metastasis. Hereby, we develop engineered nanovesicles displaying CCR1 and TGFBR2 molecules (C/T-NVs) to chemotactically target the tumor driven by CCL9/CCR1 axis and trap TGF- through TGF--TGFBR2 specific binding. Chemotactic C/T-NVs counteract CCR1-G-MDSC infiltration through competitive responding CCL9/CCR1 axis. C/T-NVs-induced intratumoral TGF- exhaustion alleviates the TGF--suppressed immune response of CTLs. Collectively, C/T-NVs attenuate liver metastasis of SMAD4-deficient CRC. In further exploration, high expression of programmed cell death ligand-1 (PD-L1) is observed in clinical specimens of SMAD4-deficient CRC. Combining C/T-NVs with anti-PD-L1 antibody (aPD-L1) induces tertiary lymphoid structure formation with sustained activation of CTLs, CXCL13-CD4 T, CXCR5-CD20 B cells, and enhanced secretion of cytotoxic cytokine interleukin-21 and IFN- around tumors, thus eradicating metastatic foci. Our strategy elicits pleiotropic antimetastatic immunity, paving the way for nanovesicle-mediated precision immunotherapy in SMAD4-deficient CRC.