Selection of microRNAs in extracellular vesicles for diagnosis of malignant pleural mesothelioma by in vitro analysis.

Malignant pleural mesothelioma (MPM) is a malignant tumor which is a challenge for diagnosis and is associated with a poor patient prognosis. Thus, early diagnostic interventions will improve the quality of life and life expectancy of these patients. Recently, cellular microRNAs (miRNAs) have been found to be involved in maintaining homeostasis, and abnormal miRNA expression has often been observed in various diseases including cancer. Extracellular vesicles (EVs) released by many cells contain proteins and nucleic acids. miRNAs are secreted from all cells via EVs and circulate throughout the body. In this study, culture media were passed sequentially through membrane filters 220‑50 nm in size, and EVs with diameters of 50 to 220 nm (EVcap50/220) were collected. miRNAs (EV50‑miRNAs) in EVcap50/220 were purified, and microarray analysis was performed. EV50‑miRNA expression profiles were compared between MPM cells and a normal pleural mesothelial cell line, and six EV50‑miRNAs were selected for further investigation. Of these, hsa‑miR‑193a‑5p and hsa‑miR‑551b‑5p demonstrated higher expression in MPM‑derived EVcap50/220. These miRNAs reduced the expression of several genes involved in cell‑cell interactions and cell‑matrix interactions in normal pleural mesothelial cells. Our data suggest that hsa‑miR‑193a‑5p and hsa‑miR‑551b‑5p in EVcap50/220 could be diagnostic markers for MPM.