MicroRNA-27a-3p regulates epithelial to mesenchymal transition via targeting YAP1 in oral squamous cell carcinoma cells.

MicroRNAs (miRNAs) are small non-coding RNAs frequently dysregulated in human malignancies. Here, we profiled isolated cells from freshly resected tumors from oral squamous cell carcinoma (OSCC) patients and OSCC cell lines using a SYBR Green-based qPCR miRNA array to identify the expression change of the miRNAs. Based on the microarray data and clincopathological factor analysis of 50 OSCC patients related to these miRNAs, miR-27a-3p was selected as a putative miRNA which might play important role in OSCC progression. By bioinformatics analysis and dual-luciferase reporter assay, we found that YAP1 (Yes-associated protein-1) was a direct target gene of miR-27a-3p. Intriguingly, increased expression of miR-27a-3p could significantly decrease the expression level of YAP1 as well as several epithelial to mesenchymal transition (EMT)-related molecules in OSCC cell lines, including Twist and Snail. Then, follow-up studies revealed that miR-27a-3p expression was able to downregulate the EMT-related molecules effectively, which might be involved in the regulation of Sox2 via the YAP1-OCT4-Sox2 signaling axis. In summary, this study found that miR-27a-3p could inhibit the YAP1 directly by post-transcriptionally silencing and potentially suppress EMT process, suggesting that miR‑27a-3p might play pivotal roles in effectively manipulating the invasion and metastasis in oral squamous cell carcinoma cells through the EMT inhibition.