Long Intergenic Non-coding RNA 00152 Promotes Lung Adenocarcinoma Proliferation Via Interacting With EZH2 And Repressing IL24 Expression

Background:Numerous studies have shown that long non-coding RNAs(lncRNAs)behave as a novel class of transcript during multiple cancer processes,such as cell proliferation,apoptosis,migration,and invasion.LINC00152 is located on chromosome 2p11.2,and has a transcript length of 828 nucleotides.Some reports suggested that LINC00152 dysregulation is associated with the development of gastric cancer and hepatocellular carcinoma.But the biological role of LINC00152 in LAD(lung adenocarcinoma)remains unknown.Objective:This study is aimed to detect LINC00152 expression in LAD and to evaluate the function and potential mechanisms of LINC00152 in LAD progression.Methods:(1)LINC00152 levels in LAD was screened by TCGA database.(2)Quantitative reverse transcription PCR(qRT-PCR)was used to detect LINC00152 expression in 60 human LAD tissues and paired normal tissues.(3)In vitro assays were used to evaluate the viability of LAD cells transfected with si-LINC00152.(4)In vivo studies was performed to observe the tumor formation ability of A549 cell after knockdown LINC00152 on nude mice.(5)Microarray was used to screen downstream target genes that regulated by LINC00152.(6)qRT-PCR and Western blot further varified target genes.(7)Subcellular fractionation,RNA immunoprecipitation(RIP)assay,RNA pulldown assa and,Chromatin immunoprecipitation assay were used to explore the underlying mechanism that how LINC00152 regulate IL24.(8)IL24 overexpression plasmid was built and rescue experiment was performed to observe whether IL24 was modulated by LINC00152.Results:(1)It was found that LINC00152 was highly expressed in LAD tissues via TCGA database.(2)LINC00152 expression was upregulated in 60 human LAD tissues and related cancer cell lines.High levels of LINC00152 expression were correlated with advanced TNM stage,larger tumor size,and lymph node metastasis.LINC00152 could behave as poor predictor of LAD.(3)In vitro studies revealed that LINC00152 silencing could inhibit LAD cell proliferation and induce G1 arrest and cell apoptosis.(4)In vivo studies suggested that tumor formation ability of A549 could be reduced after LINC00152 knockdown.(5)Microarray assays showed that IL24 was upregulated after LINC00152 knockdown.(6)qRT-PCR and Western blot was used to testify that IL24 was upregulated at mRNA and protein levels after LINC00152 knockdown.(7)Subcellular fractionation,RNA immunoprecipitation(RIP)assay and RNA pulldown assay showed that LINC00152 could recruit EZH2 and LSD1.ChIP assay showed that LINC00152 silenced IL24 transcription by recruiting EZH2(instead of LSD1)to the IL24 promoter region.(8)Rescue experiments indicated that overexpression of IL24 could partly inverse the oncogenic effect of LINC00152 in LAD.Conclusions:Our study reveals an oncogenic role for LINC00152 in LAD tumorigenesis.LINC00152 promoted LAD proliferation via repressing IL24 expression.It was suggested that LINC00152 could be used as a therapeutic target in LAD treatment.