Downregulation of long non-coding RNA XIST inhibits cell proliferation, migration, invasion and EMT by regulating miR-212-3p/CBLL1 axis in non-small cell lung cancer cells.

Abstract

Non-small cell lung cancer (NSCLC) is one of the most common malignant tumors in the world and its 5-year survival rate is very low. Long non-coding RNA X-inactive specific transcript (lncRNA XIST) has been demonstrated to play vital roles in NSCLC, but the exact molecular mechanisms underlying NSCLC still need to be further explored. Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) was performed to detect the expression of XIST, miR-212-3p and Casitas B-lineage proto-oncogene like 1 (CBLL1). Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were conducted to analyze the relationship among XIST, miR-212-3p and CBLL1. Cell Counting Kit-8 (CCK-8) assay and transwell invasion assay were carried out to evaluate cell proliferation, migration and invasion, respectively. Western blot analysis was conducted to examine the protein expression of CBLL1, E-cadherin, N-cadherin and Vimentin. Murine xenograft assay was conducted to explore the role of XIST in vivo. Expression levels of XIST and CBLL1 were markedly upregulated, while the miR-212-3p level was markedly downregulated in NSCLC tissues and cells. MiR-212-3p was identified as a direct target of XIST, and miR-212-3p was predicted to target CBLL1. XIST knockdown repressed NSCLC cell proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) in vitro, and suppressed tumor growth in vivo, while miR-212-3p inhibition restored the effects. Furthermore, CBLL1 overexpression could abolish the effects of miR-212-3p overexpression on NSCLC cell proliferation, migration, invasion and EMT in vitro. XIST was significantly decreased in NSCLC tissues and cells, and XIST knockdown suppressed the proliferation, migration, invasion and EMT of NSCLC cells by miR-212-3p/CBLL1 axis. These findings facilitated our understanding of lncRNA regulation in NSCLC.