MicroRNA-1289 functions as a novel tumor suppressor in oral squamous cell carcinoma

Recently, a number of tumor suppressive microRNAs (TS-miRs) have been found in human ma-lignancies. In this study, we have attempted to identify a novel TS-miR in oral squamous cell carcinoma (OSCC) using function-based screening. First, we transfected human OSCC cells with 968 synthetic mimicking human mature miRs individually, and then the growth of these cells was evaluated. Five miRs significantly reduced the cell growth rate by less than 30%, and miR-1289 had the most potent growth inhibitory effect among these miRs. Next, miR-1289/atelocollagen complex administration significantly reduced the size of subcutaneously xenografted human OSCC tumors. Furthermore, the expression levels of miR-1289 were significant decreased in OSCC tissues compared to adjacent normal oral mucosa. Finally, we identified magnesium transporter 1 as a target gene of miR-1289. These results suggest that miR-1289 functions as a novel TS-miR in OSCC, and may be a useful therapeutic tool for the patients with OSCC. We explored the target genes of miR-1289 in human oral squamous cell carcinoma cells using microarray analysis. We compared the gene expression profiles of 3 human oral squamous cell carcinoma cell lines treated with miR-1289 mimic and miR-non traget (NT).