Despite the numerous conventional and alternative and complementary treatment options available for cancer the medical community continues to search for safer and more effective treatments. A relatively new area of study in cancer research is cell to cell communication and the role of exosomes.
Exosomes are extraordinarily tiny vesicles used by various cells of the body for cell-to-cell communication. They contain signaling molecules including mRNA, miRNA, proteins as well as growth factors which influence the function and behavior of nearby or distant target cells.
In recent year’s research on the pathological and therapeutic roles of exosomes has greatly increased. Researchers now recognize that exosomes play a significant role in pathology of many diseases and regulate numerous physiological processes including immune surveillance, tissue repair, inflammation, etc.
In addition to the number of therapeutic properties exosomes have been shown to have, emerging research suggests that due to their role in transporting signals between cells, exosomes could be used as a vehicle for drug delivery and vaccine therapy in cancer.
The study entitled “Vaccination of metastatic melanoma patients with autologous dendritic cell (DC) derived-exosomes: results of the first phase 1 clinical trial,” investigated the feasibility and safety of exosome therapy with MAGE3 tumor specific antigens for the immunization of melanoma patients.
The exosomes used in this study were isolated from dendritic cells (a specific type of immune cell involved with presenting information to other immune cells) of patients undergoing the therapy. In vitro studies have demonstrated that dendritic cell derived exosomes, also known as dexosomes, prime specific immune cells involved with tumor surveillance and eradication via cell to cell communication. Dexosomes have also been shown to have significant anti-tumor activity in rodent cancer models.
The isolated dexosomes were then loaded with MAGE3 tumor antigens, tumor specific proteins that many tumors including melanoma, non-small cell lung cancer, and others exert on their cell surface. These tumor antigens are used as biological markers in tumor surveillance by cells of the immune system. Loaded with MAGE3 antigens the dexosomes act as a vehicle for transmitting them to other immune cells in order to invoke an immune response. This is the concept of using exosomes for cancer vaccine.
Fifteen patients received four exosome vaccinations and were evaluated before and 2 weeks after treatment. As this is a Phase 1 trial their primary objective is to demonstrate tolerability and safety. Results demonstrate that the therapy was well tolerated as there were no reports of grade 2 toxicity.
The author’s concluded that “the first exosome phase 1 trial highlighted the feasibility of large scale exosome production and the safety of exosome administration.”
Although, more large scale human clinical trials are needed to confirm safety and efficacy, exosomes are a promising new therapy in cancer treatment.