The Multiple Roles of Exosomes in Metastasis

Exosomes are important contributors to cell-cell communication and their role as diagnostic markers for cancer and the pathogenesis for cancer is under intensive investigation. Here, researchers at Roche Diagnostics GmbH focus on their role in metastasis-related processes. They discuss their impact regarding promotion of invasion and migration of tumor cells, conditioning of lymph nodes, generation of premetastatic niches and organotropism of metastasis. Furthermore, they highlight interactions of exosomes with bone marrow and stromal components such as fibroblasts, endothelial cells, myeloid- and other immune-related cells in the context of metastases. For all processes as described above, the researchers outline molecular and cellular components for therapeutic intervention with metastatic processes.

Interplay between tumor cells, other cell types, secreted factors
and exosomes in the creation of pre- and metastatic niches

Exosomes and secreted factors are indicated by green circles or red squares, respectively. α5β6, α6β1 and α6β4,integrins; CAF, cancer-associated fibroblast; CCL2, CC chemokine ligand 2; cMET, tyrosine kinase receptor c-MET; CXCL2, chemokine (C-X-C motif) ligand 2; DC, dendritic cell; DTC, disseminated tumor cell; EC, endothelial cell; EPC, endothelial progenitor cell; HPC, hematopoietic progenitor cell; LOX, lysyl oxidase; MDSC, myeloid-derived suppressor cell; MIF, macrophage migration inhibitory factor; MMP9, matrix metalloprotease 9; MP, macrophage; MSC, mesenchymal stem cell; NK, natural killer cell; NTP, neutrophile; PLGF, pacental growth factor; S100A8/9, S100 calcium binding protein A8 or A9; TC, tumor cell; Tcyt, cytotoxic T-cell; TGFβ, transforming growth factor β; TNFα, tumor necrosis factor α; Tregs, regulatory T-cells; VEGFA, vascular endothelial growth factor, isoform A.