Engineered Exosome Delivery of Apoptin as Tumor Therapeutic

Abstract Apopotin is a small protein that can specifically induce apoptosis in tumor cells, thereby selectively killing a variety of human cancer cells. However, penetrating the cell membrane is often challenging and exosome is sometimes leveraged to deliver functional molecules into cells. As the expression of fusion lysosomal-associated membrane protein 2b (LAMP-2B) can integrate exogenous proteins into the exosome membrane, we investigated the ability of apoptin-armed exosomes to penetrate tumor cells and induce apoptosis. In this study, the recombinant plasmid Apoptin-EGFP-Lamp2b was constructed and transfected into COS-7 cells. The Apoptin-EGFP-Lamp2b recombinant fusion protein was expressed and rendered apoptin was displayed on the surface of exosomes. Our study showed that the engineered apoptin-containing exosomes could deliver apopotin across the cell membrane into the nucleus. CCK8 cytotoxicity tests demonstrated that apoptin- containing exosomes could specifically target and kill cancer cells. In addition, Hoechst33342 staining and Annexin-V-FITC/PI method were used to observe the ability of exosome mediated apoptin to induce apoptosis. These results showed that the engineered exosome could successfully deliver apoptin into cancer cells and induce apoptosis, indicating that exosomes could be used as a new type of protein delivery platform.This study developed a powerful apoptin- anchored exosome as a potential for tumor-specific therapy.