MicroRNA profiling of plasma exosomes from patients with ovarian cancer using high-throughput sequencing

To the best of our knowledge, the microRNA (miR/miRNA) expression profile of plasma exosomes in ovarian cancer has not been previously studied. The aim of the present study was to investigate the practicality of using plasma exosomal miRNAs as novel serological biomarkers of ovarian cancer. In the study, exosome-like vesicles were purified from the plasma of patients with ovarian cancer and healthy women using differential centrifugation. The purified vesicles, ranging from 50–100 nm in size, were identified as exosomes by transmission electron microscopy and western blotting. High-throughput sequencing demonstrated that 65 known miRNAs, 34 of which were upregulated and 31 downregulated, were differentially expressed between patients with ovarian cancer and healthy women (P<0.05; fold change ≥2). The miRNA expression levels of hsa-miR-106a-5p, hsa-let-7d-5p and hsa-miR-93-5p were significantly increased, whereas hsa-miR-122-5p, hsa-miR-185-5p and hsa-miR-99b-5p expression levels were significantly decreased in the exosomes of patients with ovarian cancer compared with those in the healthy controls. Additionally, the miRNA expression levels of plasma hsa-miR-93-5p were significantly increased in patients with ovarian cancer compared with those in the healthy controls, while the plasma expression levels of hsa-miR-122-5p and hsa-miR-99b-5p were significantly decreased in patients with ovarian cancer compared with those in the healthy controls. Overall, the present study identified plasma and exosomal miRNAs with dysregulated expression in patients with ovarian cancer compared with that in healthy controls, and the differentially expressed miRNAs may have potential as diagnostic and prognostic targets for the treatment of patients with ovarian cancer.