Multilateral strategies utilizing exosomes for cancer therapy

Exosomes are nano-sized extracellular vesicles which transfer their components such as RNA, DNA, and proteins from one cell to another cell. The components are released to the cytoplasm of the recipient cells, having an effect on the cells. Cancer-derived exosomes promote cancer progression, invasion, gain of drug resistance, and metastasis. Recently, according to their characteristics, it is expected to apply exosomes to cancer therapies, such as utilizing exosomes as drug delivery systems (DDS) for anticancer drugs and as cancer vaccines to enhance immunity to cancer cells. More, as the cancer-derived exosomes have cancer-promoting effects on multiple stages, inhibiting the function of the cancer-derived exosomes would be helpful to cancer therapies by suppressing cancer progression. DDS and cancer vaccines utilizing exosomes are now undergoing clinical studies, although DDS is suffering from loading efficiency. Treatments by inhibiting the functions of cancer-derived exosomes have still only few reports at experimental levels. Recently, we showed in a mouse model that disruption of cancer-derived exosomes by antibodies could suppress lung metastasis of the human breast cancer cells. Exosomes will provide us the multiple strategies to fight with cancer, which can be applied to cancers from many organs. It is important to confirm safety and overcome technical problems to bring exosomes in practical use.