RESUMO
Each type of cancer has its own specific metastatic route developed by disseminating circulating tumor cells (CTCs) and related extracellular vesicles to the target organ, i.e., metastasis organotropism. Tumor-derived small extracellular vesicles (herein exosomes, EXO) play an important role in determining cancer organotropic metastases to pre-metastasis niches. We therefore hypothesized that drug-loaded EXO may mix well with their companion small extracellular vesicles to specifically target the aimed metastatic organ via organotropism. Here, we demonstrate that the circulating breast-cancer-derived EXO loaded with doxorubicin (EXO-DOX) can mingled with their original companion EXO and inhibit breast cancer metastasis to lungs. The CD47 on the EXO-DOX prevented EXO-DOX from immune attack and prolonged their circulation in blood. The tissue distribution ratio of EXO-DOX is identical to the ratio of their companion EXO due to the specific affinity of EXO to integrins in targeted tissues. Quantitative accumulation of EXO-DOX in the mouse lungs is proportional to the organotropism of the circulating breast cancer cells that disseminate from subcutaneously-implanted human breast cancer cells in mice. EXO-DOX inhibited angiogenesis and cancer cell proliferation, resulting in prevention of breast cancer metastasis to the lungs. This study opens a novel path to use Trojan small extracellular vesicles for specifically controlled release of active components by small extracellular vesicles organotropism mechanism to the targeted organ for disease chemoprevention.