A novel microRNA identified in hepatocellular carcinomas is responsive to LEF1 and facilitates proliferation and epithelial-mesenchymal transition via targeting of NFIX.

Hepatocellular carcinoma ( HCC) is one of the most prevalent cancers. It has been demonstrated that various cellular microRNAs (miRNAs) play an important role in HCCdevelopment. Here, we analyzed the miRNA profile in HCCtissues by Solexa sequencing, and we identified a novel microRNA, miR-HCC1, which is upregulated in HCCtissues. Further experiments showed that miR-HCC1 promoted HCCcell proliferation in vivo and in vitro, and migration and invasion resulting from the epithelial-mesenchymal transition(EMT) process. Nuclear factor I/X ( NFIX), which inhibited cell proliferation, migration and invasion in HCCcells, was identified as a direct and functional target of miR-HCC1. Furthermore, lymphoid enhancer binding factor 1(LEF1), a transcription factor, was shown to bind the promoter of miR-HCC1 and activate its expression. Collectively, these results indicate that LEF1-upregulated miR-HCC1 functions as an oncogene through the negative regulation of NFIXexpression, which links the LEF1/miR-HCC1/ NFIXaxis to contribute to cell proliferation, migration and invasion of HCCcells and could provide novel insights into miRNA function and hepatocarcinogenesis and potential biomarkers for HCC.