Homotypic targeting exosomes mediating a “dual-strike” strategy for stromal suppression and enhanced chemotherapy in colorectal cancer

Objectives Desmoplastic stroma and cancer-associated fibroblasts (CAFs) constitute major barriers to effective drug delivery and antitumor responses in colorectal cancer (CRC). This study aimed to develop a biomimetic exosome-based nanoplatform capable of combining tumor-directed chemotherapy with stromal modulation to improve therapeutic efficacy against CRC. Methods HCT116 cell-derived exosomes were engineered with DSPE-PEG 2000 and loaded with doxorubicin (DOX) and anti-fibroblast activation protein antibody (a-FAP) to construct DF@DP-Exo. The physicochemical properties, cellular uptake, antitumor activity, CAF modulation, and hemocompatibility of the nanoplatform were evaluated in vitro . Its therapeutic efficacy, effects on angiogenic markers and T cell infiltration, and systemic biosafety were further assessed in HCT116 xenograft and immunocompetent CT26 tumor models. Results An engineered exosome-based nanoplatform, DF@DP-Exo, was successfully constructed and showed favorable physicochemical characteristics. DF@DP-Exo exhibited efficient cellular internalization and preferential uptake by HCT116 cells compared with SW480 cells. In vitro , DF@DP-Exo inhibited HCT116 cell viability by 80.3%, suppressed cell migration and colony formation, and reduced CAF viability, TGF-β1 levels, and FAP expression. In vivo , DF@DP-Exo significantly suppressed tumor progression in both HCT116 xenograft and CT26 tumor models, accompanied by increased tumor-cell apoptosis and reduced expression of CD31 and VEGFR2. Increased intratumoral CD4 + and CD8 + T cell infiltration was also observed. Serum biochemical analyses and histological examination of major organs revealed no significant treatment-related systemic toxicity. Conclusions DF@DP-Exo integrates homotypic exosome-mediated tumor targeting, FAP-directed stromal modulation, and DOX delivery within a single nanoplatform. This dual-strike strategy demonstrated antitumor activity in CRC models, accompanied by stromal modulation, reduced angiogenic marker expression, and increased intratumoral T cell infiltration. These findings support further investigation of DF@DP-Exo as a potential therapeutic strategy for stroma-rich CRC.