Exosomal miRNA423-5p mediated oncogene activity in papillary thyroid carcinoma: a potential diagnostic and biological target for cancer therapy.

Exosomes are considered important "messengers" between cells and their cargo, and some of the miRNAs composing their cargo may be involved in oncogenic activity. Exosomal miRNA423-5p (Ex-miRNA423-5p) is upregulated in gastric cancer and associated with its poor prognosis. However, the role of exosome-derived miRNAs in papillary thyroid cancer (PTC) is still unclear and needs further study. In our work, we found that the level of Ex-miRNA423-5p was significantly increased in the serum of PTC patients compared with the serum of normal healthy people, and in vitro, we demonstrated that miRNA423-5p entered thyroid cancer cells through exosomes from thyroid cancer cell supernatant. Functional experiments demonstrated that overexpression of miRNA423-5p mimics in exosomes increased PTC cell migration and invasion, while the silencing of miRNA423-5p in TPC-1 cell exosomes inhibited PTC cell migration and invasion in vitro. These findings indicate that Ex- miRNA423-5p might serve as a potential tumor marker; thus, silencing miRNA423-5p in exosomes might represent a potential approach against PTC.