Objective: 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.
Patients and methods: 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.
Results: 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.
Conclusions: 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.