microRNA-23B inhibits non-small cell lung cancer proliferation, invasion and migration via downregulation of RUNX2 and inhibition of Wnt/Β-catenin signaling pathway

Non-small cell lung cancer (NSCLC) accounts for about 85% of all lung cancer cases. MicroRNAs (miRNAs/miRs) have been reported to play significant roles in the progression of human tumors, however, the expression and biological role of miR-23b in NSCLC remains elusive. Underexpression of miR-23b was detected in NSCLC tissues in comparison with the matched para-carcinoma tissues. The clinical value of miR-23b was analyzed, and the findings showed that miR-23b expression was negatively correlated with poor overall survival and malignant clinicopathologic characteristics of NSCLC patients. Furthermore, functional assays demonstrated that overexpression of miR-23b inhibited NSCLC cell viability, invasion and migration. Luciferase reporter assay and qRT-PCR revealed that RUNX2 was a functional target of miR-23b. The elevated expression of RUNX2 was positively correlated with overall survival of NSCLC patients. Additionally, Western blot analysis indicated that EMT and Wnt/β-catenin pathways were blocked by the upregulation of miR-23b. Taken together, these data demonstrated that dysregulation of miR-23b/RUNX2 signal may be a novel therapeutic target for the treatment of NSCLC.

MiR-20a promotes lung tumorigenesis by targeting RUNX3 via TGF-β signaling pathway

MiR-20a shows a significant role in the development of various human tumors. However, its specific biological function in non-small-cell lung cancer (NSCLC) is still not clear. qRT-PCR was applied for detecting miR-20a expression. The analysis of cell growth and apoptosis were performed by MTT, xenograft models, Western blot assays. Dual luciferase reporter, Western blotting and qRT-PCR were carried out to verify the potential target of miR-20a. In NSCLC tissues and cells, miR-20a was highly expressed and RUNX3 was lowly expressed. Moreover, up-regulation of miR-20a expression promoted NSCLC cell proliferation, invasion and migration, while low-expression of miR-20a showed the converse case on cell proliferation, invasion and migration. RUNX3 was verified as the direct target of miR-20a and it could overturn its biological function in NSCLC cells. Moreover, miR-20a negatively regulated RUNX3 expression. Mechanistically, increasing miR-20a expression inhibited RUNX3 expression and then activated the TGF-β signaling pathway. Taken together, our results demonstrated that re-expression of miR-20a promoted lung tumorigenesis by down-regulation of RUNX3 and facilitating the activation of TGF-β signaling pathway.