We identified that miR-31 directly targeted SIRT3 in OSCC cells, and a reverse correlation between miR-31 expression and SIRT3 expression was noted in OSCC tumors.
The resulting hypothesis is possible that the tissue-specific features of adenocarcinoma and squamous cell cancer and the positive feedback loop consists of miR-31 and its upstream and downstream may account for the diversity of miR-31 functions.
We demonstrate that miR-31 is significantly decreased in invasive esophageal cancer cells, while upregulation of miR-31 inhibits growth, migration and invasion of esophageal adenocarcinoma (EAC) and squamous cell carcinoma (ESCC) cell lines. miR-31, in turn, targets SOX4 for degradation by directly binding to its 3'-UTR.
miR-31(*) is a functional miRNA involving in regulating RhoA, and the activity of miR-31(*)'s activity seems to counteract the functions of miR-31 during OSCC tumorigenesis.
In comparison to normal epithelium, miR-21 was overexpressed in both VC and SCC and miR-31 was overexpressed in VC and in well- and moderately differentiated SCC.
We also showed that high expression of hsa-miR-31 was associated with poor survival in these 60 SCC patients by Kaplan-Meier analysis (P = 0.007), by univariate Cox analysis (P = 0.011), and by multivariate Cox analysis (P = 0.011).