Exosomes in cancer immunotherapy

Abstract

In recent years, immunotherapy has become a promising treatment for patients with cancer. Exosomes, tiny vesicles released from cells of most types, are an intercellular communication tool that plays a role in the anticancer immune response. In particular, exosomes secreted from tumor cells have been shown to negatively regulate the immune system. The mechanisms underlying the immunosuppressive effect of tumor exosomes include suppression of helper and cytotoxic T cells, natural killer cells, and dendritic cells and the induction of immunosuppressive cells such as regulatory T cells and myeloid-derived suppressor cells. Therefore, tumor exosomes should be regarded as an important target for effective cancer immunotherapies. In addition, exosomes can be used in cancer immunotherapies as endogenous delivery carriers. There are several reports of the successful application of exosomes to cancer immunotherapies. In this chapter, the roles and effects of exosomes in cancer immunotherapy are described.