Long non-coding RNA LINC00152 regulates cell proliferation and migration by epigenetically repressing LRIG1 expression in cholangiocarcinoma

Background: Recently, long non-coding RNAs (lncRNAs) have been verified to have significant regulatory roles in multiple human cancer processes. Long non-coding RNA LINC00152, located on chromosome 2p11.2, was identified as an oncogenic lncRNA in various cancers. However, the biological function and molecular mechanism of LINC00152 in cholangiocarcinoma (CCA) are still unknown.Methods: Bioinformatic analysis was performed to determine LINC00152 expression levels in the CCA and normal tissues by using raw microarray data downloaded from Gene Expression Omnibus (GSE76297) and The Cancer Genome Atlas (TCGA). Quantitative reverse transcription PCR (qRT-PCR) was used to validate LINC00152 expression in the CCA tissues compared with that in the paired normal tissues. CCK8, colony formation, Edu assays, transwell assays, flow cytometry, and in vivo tumor formation assays were performed to investigate the biological function of LINC00152 on CCA cell phenotypes. RNA-seq was carried out to identify the downstream target gene which was further examined by qRT-PCR, western bolt and rescue experiments. RNA immunoprecipitation (RIP) and Chromatin immunoprecipitation (ChIP) assays were performed to reveal the factors involved in the mechanism of LINC00152 functions in CCA.Results: LINC00152 is significantly upregulated in cholangiocarcinoma. LINC00152 regulated the proliferation and migration of cholangiocarcinoma cells both in vitro and in vivo. RNA-seq revealed that LINC00152 knockdown preferentially affected genes linked with cell proliferation, cell differentiation and cell adhesion. Furthermore, mechanistic investigation validated that LINC00152 could bind EZH2 and modulate the histone methylation of promoter of leucine rich repeats and immunoglobulin like domains 1 (LRIG1), thereby affecting cholangiocarcinoma cells growth and migration.Conclusion: Taken together, these results demonstrated the significant roles of LINC00152 in cholangiocarcinoma and suggested a new diagnostic and therapeutic direction of cholangiocarcinoma.