The Yin and Yang of tumour-derived extracellular vesicles in tumour immunity.

Extracellular vesicles (EVs) are small particles that are naturally released from various types of cells. EVs contain a wide variety of cellular components, such as proteins, nucleic acids, lipids and metabolites, which facilitate intercellular communication in diverse biological processes. In the tumour microenvironment, EVs have been shown to play important roles in tumour progression, including immune system-tumour interactions. Although previous studies have convincingly demonstrated the immunosuppressive functions of tumour-derived EVs, some studies have suggested that tumour-derived EVs can also stimulate host immunity, especially in therapeutic conditions. Recent studies have revealed the heterogeneous nature of EVs with different structural and biological characteristics that may account for the divergent functions of EVs in tumour immunity. In this review article, we provide a brief summary of our current understanding of tumour-derived EVs in immune activation and inhibition. We also highlight the emerging utility of EVs in the diagnosis and treatment of cancers and discuss the potential clinical applications of tumour-derived EVs.

Yamauchi T ，Moroishi T 《-》

How cancer cells dictate their microenvironment: present roles of extracellular vesicles.

Naito Y ，Yoshioka Y ，Yamamoto Y ，Ochiya T ... -  《-》

Tumor-derived extracellular vesicles: molecular parcels that enable regulation of the immune response in cancer.

Extracellular vesicles (EVs) are a heterogeneous collection of membrane-bound vesicles released by cells that contain bioactive cargoes including proteins, lipids and nucleic acids. Multiple subpopulations of EVs have now been recognized and these include exosomes and microvesicles. EVs have been thought to facilitate intercellular and distal communication to bring about various processes that enable tumor progression and metastases. Here, we describe the current knowledge of the functional cargo contained within EVs, with a focus on tumor microvesicles, and review the emerging theory of how EVs support immune suppression in cancer.

Sheehan C ，D'Souza-Schorey C 《-》

Glioma EVs Contribute to Immune Privilege in the Brain.

Glioblastoma cells release extracellular vesicles (EVs), sometimes referred to as microvesicles and exosomes, to transfer immune modulating molecules to immune cells, resulting in an immune privileged microenvironment. Here we discuss the potential EV-mediated mechanisms underlying glioma immune modulation, as well as the technical difficulties in studying these interactions.

Abels ER ，Broekman MLD ，Breakefield XO ，Maas SLN ... -  《Trends in Cancer》

Cancer-derived extracellular vesicles: friend and foe of tumour immunosurveillance.

Extracellular vesicles (EVs) are important players of intercellular signalling mechanisms, including communication with and among immune cells. EVs can affect the surrounding tissue as well as peripheral cells. Recently, EVs have been identified to be involved in the aetiology of several diseases, including cancer. Tumour cell-released EVs or exosomes have been shown to promote a tumour-supporting environment in non-malignant tissue and, thus, benefit metastasis. The underlying mechanisms are numerous: loss of antigen expression, direct suppression of immune effector cells, exchange of nucleic acids, alteration of the recipient cells' transcription and direct suppression of immune cells. Consequently, tumour cells can subvert the host's immune detection as well as suppress the immune system. On the contrary, recent studies reported the existence of EVs able to activate immune cells, thus promoting the tumour-directed immune response. In this article, the immunosuppressive capabilities of EVs, on the one hand, and their potential use in immunoactivation and therapeutic potential, on the other hand, are discussed.This article is part of the discussion meeting issue 'Extracellular vesicles and the tumour microenvironment'.

Dörsam B ，Reiners KS ，von Strandmann EP 《-》