Effects of lysate/tissue storage at −80°C on subsequently extracted EVs of epithelial ovarian cancer tissue origins

Small extracellular vesicles (sEVs) and large extracellular vesicles (lEVs), play vital roles in intercellular communication. We optimized a method that extracts EVs from epithelial ovarian cancer (EOC) tissues for the purpose of investigating whether cryopreservation of EOC tissues affects the phenotypes, contents, and biological functions of extracted EVs. EV morphology, the number and size distribution of EVs, and EV-related markers were analyzed. Storage of lysates at −80°C decreased lEV yield and increased sEV yield, whereas storage of tissues at −80°C increased both sEV and lEV yields; neither changed the morphology or particle mass ratio of EVs. The two cryopreservation groups retained over 90% of proteins and 80% of miRNAs detected in the “fresh” group. EVs extracted following lysate/tissue storage at −80°C could also promote angiogenesis and invasive migration ability in human endothelial cells. Cryopreserved EOC tissue may benefit clinical applications for studies of tissue-derived EVs, especially EV proteins-related ones. [Display omitted] •The two frozen methods altered the yield of EOC tissue-derived EVs•The two “frozen” groups retained 90% proteins and 80% miRNAs of the “fresh” group•The two frozen methods did not affect the biological function of EOC tissue-derived EVs Cell biology; Cancer; Methodology in biological sciences