Abstract
A cluster of differentiation 47 (CD47) and immune-modulatory protein for myeloid cells has been implicated in cisplatin (CDDP) resistance. Exosome delivery of drugs has shown great potential for targeted drug delivery in the treatment of various diseases. In the current study, we explored the approach of co-delivering CDDP and CD47 antibody with MDA-MB-231 cell-derived exosome 231-exo (CaCE) and assessed the phagocytosis activity of bone marrow flow cytometry derived macrophages (BMDM) against co-cultured A549 cells. CD8+ T-cell proliferation was examined with flow cytometry analysis. In vivo, we used the Lewis lung carcinoma (LLC) tumor-bearing mouse model and assessed survival rate, tumor weight, phagocytosis, and T-cell proliferation, as well as cytokine levels in tumors analyzed by enzyme-linked immunoassay (ELISA). Although co-administration of CDDP with anti-CD47 (CDDP and aCD47) showed a significant antitumor effect, CaCE had an even more dramatic anticancer effect in survival rate and tumor weight. We observed increased phagocytosis activity selectively against lung tumor cells in vivo and in vitro with exosome CaCE treatment. CaCE treatment also increased T-cell proliferation compared to the vehicle treatment and co-administration groups. Furthermore, immunostimulatory interleukin (IL)-12p and interferon (IFN)-γ were increased, whereas transforming growth factor β (TGF-β) were decreased, indicating the improved CDDP anticancer effect is related to a tumor microenvironmental change. Our study demonstrates a dramatically improved anticancer effect of CDDP when administered by exosome co-delivery with anti-CD47.