LncRNA NUTM2A-AS1 aggravates the progression of hepatocellular carcinoma by activating the miR-186-5p/KLF7-mediated Wnt/beta-catenin pathway

Abstract

Emerging evidence has uncovered that noncoding RNAs (ncRNAs) contribute to the development of hepatocellular carcinoma (HCC). Nevertheless, the functions of the majority of long ncRNAs (lncRNAs) in HCC are unknown. Here, we intend to probe the function of lncRNA NUTM2A-AS1 in the evolvement of HCC and the related mechanism. Expression levels of lncRNA NUTM2A-AS1, miR-186-5p and KLF7 mRNA in HCC tissues and adjacent non-tumor tissues were monitored. Gain- or loss-of-function assays were utilized to investigate the biological functions of lncRNA NUTM2A-AS1, miR-186-5p and KLF7 in HCC cell lines (including HCCLM3 and Huh7). Western blot was implemented for the detection of the epithelial-mesenchymal transition (EMT)-related proteins (including E-cadherin, Vimentin and Snail), KLF7, Wnt, β-catenin, and stemness-related proteins (Nanog, OCT4, YKL40, and CD133). Furthermore, the targeted associations between lncRNA NUTM2A-AS1, miR-186-5p, and KLF7 were verified by bioinformatics analysis, dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. As a result, lncRNA NUTM2A-AS1 and KLF7 profiles were heightened in the HCC tissues versus adjacent normal tissues, while miR-186-5p had the opposite expression tendency. Up-regulation of lncRNA NUTM2A-AS1 was related to tumor size, advanced tumor stage, and lymph node metastasis of HCC patients. Functionally, overexpression of lncRNA NUTM2A-AS1 heightened HCC cells' growth, invasion, EMT, and stemness and repressed their apoptosis by activating the Wnt/β-catenin pathway. In contrast, up-regulation of miR-186-5p or inhibition of KLF7 had reverse effects. In vivo, lncRNA NUTM2A-AS1 overexpression facilitated tumor growth and EMT, accompanied by declined miR-186-5p levels and enhanced KLF7 expression. The mechanistic studies revealed that miR-186-5p served as a common target of lncRNA NUTM2A-AS1 and KLF7. As hinted by the rescue experiments, NUTM2A-AS1 partly abated miR-186-5p-mediated anti-tumor effects in HCC cells, whereas KLF7 knockdown reversed the promotive effects of NUTM2A-AS1. LncRNA NUTM2A-AS1 accelerated the evolution of HCC by up-regulating the KLF7/Wnt/beta-catenin pathway through sponging miR-186-5p.

Keywords: Competing endogenous RNA; Hepatocellular carcinoma; LncRNA NUTM2A-AS1; miR-186-5p.