MicroRNA-10b regulates epithelial-mesenchymal transition by modulating KLF4/KLF11/Smads in hepatocellular carcinoma.

Background: Our previous work showed that miR-10b was overexpressed in hepatocellular carcinoma (HCC) and promoted HCC cell migration and invasion. Epithelial-mesenchymal transition (EMT) is involved in HCC metastasis. So, we suspected that miR-10b might participate in the HCC EMT.

Methods: We performed morphological analysis and immunofluorescence to observe the roles of miR-10b in HCC EMT. The expression of KLF11 and EMT markers were detected by real-time RT-PCR and western blot. The regulation roles of miR-10b on KLF11 and KLF4 were determined by luciferase reporter assay. The chromatin immunoprecipitation revealed the binding relationship between KLF4 and KLF11.

Results: We found that overexpression of miR-10b could promote HCC EMT. miR-10b could upregulated KLF11 expression. The upregulation of KLF11 reduced the downstream molecular Smad7 expression, which upregulated the Smad3 expression to promote EMT development. Furthermore, the induction role of miR-10b in HCC EMT could be blocked by KLF11 siRNA. But our results showed that there was no direct regulation of miR-10b in KLF11 expression. Specifically, miR-10b could bind to the 3'UTR of KLF4 and inhibit KLF4 expression. KLF4 could directly bind to KLF11 promoter and downregulate KLF11 transcription.

Conclusion: Our results reveal that miR-10b downregulates KLF4, the inhibitory transcriptional factor of KLF11, which induces Smads signaling activity to promote HCC EMT. Our study presents the regulation mechanism of miR-10b in EMT through the KLF4/KLF11/Smads pathway for the first time and implicates miR-10b as a potential target for HCC therapies.