Extracellular vesicles, especially small extracellular vesicles (sEVs) are now accepted as important messengers in cell-to-cell communication and as a promising drug delivery platform. They are involved in nearly all physiological and pathological processes and are involved in disease diagnosis and therapy. However, their heterogeneity of physicochemical properties and functions is not fully understood, which hinders further clinical applications. To obtain highly bioactive sEVs with both high yield and purity, will certainly facilitate their future study and application. This review informs up-to-date research on frequently-used and cutting-edge technologies of sEVs isolation and makes a deep comparison and analysis of different methods, including their advantages, limitations and applications. Pending questions about the inherent property of these small vesicles as well as isolation strategies are discussed. Additionally, an overview of their applications in disease diagnosis and treatment, including some of the on-going clinical trials, are also reviewed.

Gastric cancer is a malignant tumor characterized by high morbidity and invasion. Surgery combined with chemo-radiotherapy is the most common treatment for gastric cancer, while multiple drug resistance always results in treatment failure. Once the anti-tumor drugs enter the tumor foci, tumor cells as well as those found in the microenvironment are affected. However, the effects of drugs on tumor microenvironment (TME) are easily overlooked. In this study, we investigated the effects of the anti-cancer drug 3,3’-diindolylmethane (DIM) on gastric cancer-derived mesenchymal stem cells (GC-MSCs) and their subsequent impact on cancer progression. Surprisingly, we found that the therapeutic concentration of DIM upregulated the expression level of tumor-related factors such as CCL-2, IL-6, and IL-8 in GC-MSCs. The conditioned medium of DIM-treated GC-MSCs promoted the proliferation, invasion, and migration of gastric cancer cells in vitro and tumor growth in vivo. Mechanistically, DIM enhanced the expression of β-TrCP, an E3 ubiquitin ligase leading to IκBα degradation and NF-κB activation in GC-MSCs. The β-TrCP knockdown partially eliminated positive results caused by DIM. Our results showed that the therapeutic dosage of DIM induced cell death in cancer cells, while enhancing MSC paracrine functions in the stroma to offset the original DIM effect on cancer cells. These findings provide a new mechanism of anti-cancer drug resistance and remind us to adjust the chemotherapeutic scheme by combining the anti-cancer drug with an appropriate signaling pathway inhibitor to block the side effects of drug on targeted TME cells.

No abstract