LncRNA-LINC00472 suppresses the malignant progression of non-small cell lung cancer via modulation of the miRNA-1275/Homeobox A2 axis.

Abstract

Long non-coding RNAs (lncRNAs) are increasingly observed as regulatory factors for the initiation and progression of varying kinds of cancers. However, studies on lncRNAs in non-small cell lung cancer (NSCLC) progression are currently lacking. We intended to determine the role of lncRNA LINC00472 and its downstream regulatory mechanism in NSCLC, thus providing novel ideas for targeted therapies for NSCLC. The target signaling axis comprising the lncRNA/microRNA/mRNA was identified through bioinformatics analysis. Subcellular localization of LINC00472 was assessed with fluorescence in situ hybridization (FISH). Cellular function experiments were conducted to examine the proliferation, migration, invasion, and apoptosis of NSCLC cells, and dual-luciferase and RNA binding protein immunoprecipitation assays were performed to validate the binding relationship. Quantitative real-time polymerase chain reaction (qPCR) and western blot were utilized to assess the expression levels of the investigated gene and protein, respectively. The LINC00472 expression was markedly decreased in NSCLC tissues and cells. The FISH, combined with nuclear-cytoplasm separation assay, demonstrated that LINC00472 was mainly located in the cytoplasm. The overexpression of LINC00472 restrained proliferation and metastasis of NSCLC in vitro. The LINC00472 could target and repress miR-1275 level, and overexpression of LINC00472 reduced the miR-1275-dependent malignant cell phenotype in NSCLC. Further study revealed that HOXA2 was a downstream target of miR-1275 and was negatively modulated by miR-1275. Rescue assays exhibited that the overexpression of miR-1275 or inhibition of HOXA2 reversed the impact of LINC00472 overexpression on the malignant progression of NSCLC cells. The LINC00472 repressed the epithelial-mesenchymal transition (EMT) of NSCLC cells through miR-1275/HOXA2. The LINC00472 functioned as a competing endogenous RNA to modulate HOXA2 level by sponging miR-1275 in NSCLC. Simultaneously, the LINC00472/miR-1275/HOXA2 axis may be a possible therapeutic target and biomarker for NSCLC.