Blood circulating exosomes carrying microRNA-423-5p regulates cell progression in prostate cancer via targeting FRMD3

This study explored the role of circulating exosomal microRNA-423-5p in the progression of PCa and its molecular mechanism. First, based on the microarray analysis, microRNA-423-5p was at a high expression level in PCa peripheral blood samples. It was demonstrated that microRNA-423-5p expression in serum exosomes of PCa patients was notably higher than that in healthy people as revealed by qRT-PCR. Further studies indicated that overexpressing microRNA-423-5p promoted cell progression of PCa. Microarray analysis and luciferase gene reporter assay illustrated that FRMD3 was targeted by microRNA-423-5p, and its expression was down-regulated by microRNA-423-5p. While FEMD3 knockdown would reverse the repressive effect of silencing microRNA-423-5p on PCa cell functions. In addition, it was exhibited that exosomes carrying microRNA-423-5p could internalize into PCa cells by labeling and tracing exosomes. Cell function assays and animal experiments manifested those exosomes carrying microRNA-423-5p could enhance PCa cell proliferation, migration, and invasion in vivo. In conclusion, this study indicated that blood circulating exosomal microRNA-423-5p played important roles in PCa cell functions, and illustrated the molecular mechanism of microRNA-423-5p as an oncogene in PCa.