The LncRNA NEAT1 Accelerates Lung Adenocarcinoma Deterioration and Binds to Mir-193a-3p as a Competitive Endogenous RNA

Abstract

Background/Aims: Long noncoding RNAs (lncRNAs) contribute to the development of multiple malignant tumors. Here, we focused on the biological function and underlying molecular mechanism of an lncRNA, nuclear-enriched abundant transcript 1 (NEAT1), in lung adenocarcinoma (LUAD). Methods: In vitro experiments were conducted to determine the biological effects of NEAT1 in LUAD cells. A luciferase activity reporter assay was performed to corroborate the interaction between NEAT1 and miR-193a-3p. Data from Gene Expression Omnibus (GEO), Oncomine, The Cancer Genome Atlas (TCGA), and our in-house reverse transcription quantitative PCR (RT-qPCR) were combined to examine the expression of NEAT1 and miR-193a-3p in LUAD. To further explore the regulatory mechanism of NEAT1, we searched for putative target genes of miR-193a-3p from 12 online prediction databases and determined genes positively correlated with NEAT1 as candidate targets. Furthermore, we analyzed the expression of these selected genes using data from TCGA. Results: In vitro experiments showed that knockdown of NEAT1 in LUAD cells markedly restrained cell proliferation, invasion, and migration and stimulated cell apoptosis. The dual-luciferase reporter assay demonstrated that miR-193a-3p directly targeted NEAT1 at its 3’-UTR. We then detected NEAT1 and miR-193a-3p in LUAD cells and normal lung epithelial cells and discovered high expression of NEAT1 and low expression of miR-193a-3p in LUAD cell lines. Simultaneously, the pooled results from the GEO, Oncomine, TCGA, and in-house RT-qPCR showed that the NEAT1 expression increased while the miR-193a-3p expression decreased in LUAD tissues versus normal lung tissues. Furthermore, the USF1 gene was not only upregulated in LUAD, but also positively correlated with NEAT1, suggesting that NEAT1 may function as a ceRNA to sponge miR-193a-3p and abrogate the inhibitory effect of miR-193a-3p on USF1. Conclusions: Our findings indicate that NEAT1 plays important roles in the occurrence and progression of LUAD. It may exert its role by acting as a ceRNA to regulate miR-193a-3p.