Immunotherapy is expected as the fourth cancer therapy subsequently to the three pillars of cancer treatment which are surgery, radiation, and chemotherapy. Cancer immunotherapy enhances existing antitumor responses and includes the use of antibodies, lymphocytes and cytokines. Dendritic cells (DCs)-based immunotherapy is one of the cancer immunotherapies. Because DCs play a key role for immune reactions to activate T cells against cancer cells by cancer antigen presentation at cellular membrane, DCs have been used in clinical trials as cellular mediators for therapeutic vaccination of patients with cancer. The cells such as DCs and cancer cells secrete exosomes which are nano-sized extracellular microvesicles. It has reported that the exosomes released from peptide-vaccinated DCs are responsible for the persistence of antigen presentation. On the other hands, cancer cells derived exosomes play an immunosuppressive. So, we considered that whether DCs-derived exosomes could induce suppress cancer cells and more effective response of immune system against cancer with control for the cancer cells-derived exosomes. Luciferase gene transfferd-3LL cells (murine lung cancer cell line derived C57BL/6) were injected to C57BL/6J mice by intraperitoneal administration. And then, DCs, DCs-exosomes or 3LL-exosmes were weekly administrated to lung cancer bearing mice. The exosomes derived from DCs decreased lung cancer cell growth, on the other hand, lung cancer derived-exosomes increased in compared with DCs, DCs-exosomes and non-treated. For cancer immunotherapy, DC-exosomes and controlled cancer-exosomes play important roles. Currently, we are going on analyze immunosuppressive molecules possessing cancer cell-derived exosomes, and immune activation molecules in DCs-exosomes.

Citation Format: Masakatsu Takanashi, Katsuko Sudo, Shinobu Ueda, Shinichiro Ohno, Masahiko Kuroda. Analysis of dendritic cell derived exosomes that suppressed tumor growth [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2017 Oct 1-4; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2018;6(9 Suppl):Abstract nr A66.