The New Deal: A Potential Role for Secreted Vesicles in Innate Immunity and Tumor Progression

Abstract

Tumors must evade the immune system to survive and metastasize, although the mechanisms that lead to tumor immunoediting and their evasion of immune surveillance are far from clear. The first line of defense against metastatic invasion is the innate immune system that provides immediate defense through humoral immunity and cell-mediated components, mast cells, neutrophils, macrophages, and other myeloid-derived cells that protect the organism against foreign invaders. Therefore, tumors must employ different strategies to evade such immune responses or to modulate their environment, and they must do so prior metastasizing. Exosomes and other secreted vesicles can be used for cell–cell communication during tumor progression by promoting the horizontal transfer of information. In this review, we will analyze the role of such extracellular vesicles during tumor progression, summarizing the role of secreted vesicles in the crosstalk between the tumor and the innate immune system.

Human Pericardial Fluid Contains Exosomes Enriched with Cardiovascular-Expressed MicroRNAs and Promotes Therapeutic Angiogenesis

“…In line with this possibility, the positive impact of PF exosomes on blood flow recovery was not sustained over time. On the other hand, exosomes have been suggested to be able to modulate immunity 37 . Given the increasingly recognized importance of the crosstalk between the immune and cardiovascular systems in health and disease, we would not exclude that exosomes could influence cardiovascular responses partly by modulating the immune system.…”

Macrophage-Dependent Cytoplasmic Transfer during Melanoma Invasion In Vivo

“…In this work, with time-lapse imaging in in vivo and in vitro systems, we discover a mechanism by which macrophages communicate with tumor cells through cytoplasmic transfer of molecules by cell-to-cell contact. Recently, there have been a wealth of studies showing that tumor cells transfer cytoplasmic material to the microenvironment via extracellular vesicles, and furthermore, tumor-derived extracellular vesicles modulate immune interactions (Benito-Martin et al, 2015). In contrast, macrophage cytoplasmic transfer has been elusive, with one paper describing in vitro experiments using macrophage conditioned media showing that macrophages transfer oncogenic miRNAs to tumor cells (Yang et al, 2011).…”

Extracellular Vesicles in Cancer: Cell-to-Cell Mediators of Metastasis

“…Local interactions between tumors and innate immune cells ultimately determine whether the cancer can be contained locally or escape and invade both local and distant sites (Benito-Martin et al, 2015). Breast cancer cell-derived exosomes stimulate the activation of tumor-associated macrophages (TAMs), resulting in NF-κB activation and secretion of pro-inflammatory cytokines (Chow et al, 2014).…”