Exosome-mediated siRNA delivery to suppress postoperative breast cancer metastasis

High recurrence and metastasis of triple-negative breast cancer (TNBC) after operation is a leading cause of breast cancer related death. The pre-metastatic niche (PMN) is an environment in a secondary organ conducive to the metastasis of a primary tumor. Herein, we identify exosomes from autologous breast cancer cells that show effective lung targeting ability. Based on this, we developed the biomimetic nanoparticles (cationic bovine serum albumin (CBSA) conjugated siS100A4 and exosome membrane coated nanoparticles, CBSA/[email protected]) to improve drug delivery to the lung PMN. CBSA/[email protected] self-assembled nanoparticles formed homogeneous sizes of ~200 nm, protected siRNA from degradation, and showed excellent biocompatibility. Further in vivo studies showed that CBSA/[email protected] had a higher affinity toward lung in comparison to the CBSA/[email protected], and exhibited outstanding gene-silencing effects that significantly inhibited the growth of malignant breast cancer cells. Taken together, these results indicate that CBSA/[email protected] self-assembled nanoparticles are a promising strategy to suppress postoperative breast cancer metastasis.