Detection of exosome miRNAs using molecular beacons for diagnosing prostate cancer.

Prostate cancer is the fifth leading cause of cancer-related deaths among males worldwide. However, the biomarker for diagnosing prostate cancer that is used currently has limitations that must be overcome. Recently, several studies have demonstrated that the cancer liquid biopsy can be implemented by using exosome miRNAs. However, the current methods for the detection of exosome miRNAs are time-consuming, expensive, and laborious. Thus, we investigated a novel method for diagnosing prostate cancer that involves the use of molecular beacons for the in situ detection of miRNAs in exosomes from prostate cancer cells. We chose miRNA-375 and miRNA-574-3p as the target miRNAs for prostate cancer, and these markers in exosomes produced by prostate cancer cells including DU145 and PC-3 were successfully detected using molecular beacons. High fluorescent signals were obtained from MB and miRNA hybridization in exosomes in a concentration-dependent manner. In addition, exosome miRNAs can be detected even in the presence of human urine, so this method can be applied directly using human urine to perform liquid biopsies for prostate cancer. Overall, the in situ detection of exosome miRNAs using molecular beacons can be developed as a simple, cost effective, and non-invasive liquid biopsy for diagnosing prostate cancer.