MicroRNA-203 inhibits long noncoding RNA HOTAIR and regulates tumorigenesis through epithelial-to-mesenchymal transition pathway in renal cell carcinoma

This study aims to investigate the role of miR-203-HOTAIR interaction in the suppression of renal cell carcinoma (RCC). We employed series of in vitro assays such as proliferation, invasion, migration and colony formation along with in vivo tumor xenograft model. Profiling of miR-203 and HOTAIR expression revealed that miR-203 was significantly under-expressed whereas HOTAIR was overexpressed in RCC cell-lines and clinical specimens compared to normal cell line and tissue. Both miR-203 and HOTAIR expression significantly distinguished malignant from normal tissues and significantly correlated with clinicopathological characteristics of patients. Overexpression of miR-203 significantly inhibited proliferation, migration and invasion with an induction of apoptosis and cell cycle arrest. Whereas, HOTAIR suppression resulted in the similar functional effects in the same RCC cell lines. In silico RNA-22 algorithm showed a binding site for miR-203 in HOTAIR. We observed a direct interaction between miR-203 and HOTAIR by RNA-immunoprecipitation (RIP) and luciferase reporter assays. We show that miR-203-HOTAIR interaction resulted in the inhibition of epithelial to mesenchymal transition (EMT) and metastatic genes as indicated by induction of key metastasis-suppressing proteins E-cadherin, claudin (epithelial markers) and PTEN along with induction of tumor suppressor genes p21 and p27. A significant decrease in vimentin (mesenchymal-marker), KLF4 and nanog (stemness-markers) was also observed. This is the first report demonstrating miR-203 mediated regulation of HOTAIR induces tumor suppressor effects in RCC by regulating EMT and metastatic pathway genes. Thus, the study suggests that therapeutic regulation of HOTAIR by miR-203 overexpression may provide an opportunity to regulate RCC growth and metastasis.

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