LncRNA NORAD promotes thyroid carcinoma progression by targeting miR-451

Long non-coding RNA (lncRNA) NORAD plays an essential role in the development and progress of papillary thyroid carcinoma (PTC). MicroRNA-451 (MiR-451) has been identified as playing an inhibitory role in some types of cancer. However, the molecular mechanism of lncRNA NORAD regulating metastasis of PTC cells by miR-451 has not been fully elucidated.

Real-Time quantitative Polymerase Chain Reaction (RT-qPCR) or Western blot analysis of the expression of NORAD, miR-451, and interleukin-6 receptor (IL-6R) in PTC cell lines were carried out. The detection of Luciferase reporter gene showed the relationship between lncRNA NORAD, miR-451 and IL-6R. Cell Counting Kit-8 (CCK-8) assay and transwell assay were performed to detect the influence of lncRNA NORAD, miR-451 on the proliferation, migration, and invasion of PTC cells.

The results of RT-qPCR and Western blotting suggested that the expression of lncRNA NORAD and IL-6R were higher than that of the control group, while the expression of miR-451 was lower. Transwell assay indicated that the knockdown of lncRNA NORAD or overexpression of miR-451 significantly inhibited cell proliferation, migration and invasion in PTC cell lines. In addition, lncRNA NORAD negatively controls the expression of miR-451, resulting in the upregulation of IL-6R. IL-6R overexpression can reverse the inhibitory effect of lncRNA NORAD knockdown or miR-451 on PTC cell proliferation and metastasis.

Our results indicated that the cell migration and invasion were inhibited by knockdown of lncRNA NORAD or overexpression of miR-451, suggesting that the axis of lncRNA NORAD -miR-451- IL-6R was involved in the development of PTC.