Mechanism Of LINC01234 Promoting Proliferation,invasion And Metastasis Of Non-small Cell Lung Cancer

Background: The discovery of long non-coding RNAs(lnc RNAs)has greatly enhanced our understanding of tumorigenesis and cancer progression,but the mechanism of their role in the development and progression of non-small-cell lung cancer(NSCLC)remains unclear.Here,we comprehensively analyzed the changes of lnc RNA in NSCLC by analyzing high-throughput sequencing data from TCGA and GEO databases.Methods:(1)TCGA and GEO database were used to analyze the expression of LINC01234 in NSCLC tissues.(2)The relative expression of LINC01234 in NSCLC tissues and cell lines was detected by quantitative PCR.(3)MTT,clone formation assay,transwell assay,flow cytometry assays were used to evaluate the effect of LINC01234 on the proliferation and invasion of NSCLC cells.(4)The effect of LINC01234 on tumor formation ability of NSCLC cells in vivo was studied by in vivo experiment(tumor transplantation model in nude mice).(5)Chromatin immunoprecipitation assay and luciferase reporter gene assay were used to explore the upstream regulation mechanism of LINC01234.(6)Downstream regulated target genes of LINC01234 were identified by high-throughput transcriptome sequencing,and the sequencing results were verified by q RT-PCR and Western blot.(7)RNA immunoprecipitation assay,RNA pulldown assay,mass spectrometry and immunoprecipitation were used to explore the mechanism of LINC01234 regulating miRNA maturation by binding with HNRNPA2B1.(8)The upstream and downstream regulation of LINC01234 was verified by rescue experiment.Results: Compared with normal lung tissue,LINC01234 is highly expressed in non-small cell lung cancer tissues and is positively associated with poor prognosis.Downregulated expression of LINC01234 affects cell proliferation,migration and invasion in vitro and in vivo.RNA Pulldown and mass spectrometry revealed that LINC01234 interacts with the RNA binding protein HNRNPA2B1,which can recruit DGCR8 and promote the maturation of pri-miRNAs.The deletion of LINC01234 or HNRNPA2B1 resulted in reduced processing of several pri-miRNAs,such as pri-miR-106 b.In addition,miR-106 b promoted the growth of NSCLC cells by inhibiting CRY2,thereby activating c-myc expression in NSCLC.Besides,activated c-myc binds to the promoter region of LINC01234 and promotes its transcription,leading to the formation of a positive feedback loop for c-Myc-LINC01234-miR-106b-CRY2-c-Myc.LINC01234 promotes cell metastasis by acting as a competing endogenous RNA for miR-340-5p and miR-27b-3p.LINC01234 also interacts with the RNA-binding proteins LSD1 and EZH2,resulting in histone modification and transcriptional inhibition of the anti-proliferative gene BTG2.Conclusion: Our results confirm the oncogenic role of c-Myc-LINC01234-miR-106b-CRY2-c-Myc axis in the tumorigenesis of NSCLC.The role of LINC01234 in invasion and metastasis of NSCLC may be mainly through the following two regulatory axes: one is involved in miR-340-5p/miR-27b-3p in the cytoplasm;The second involves EZH2,LSD1,and BTG2 in the nucleus.This may provide a new target for diagnosis,treatment or prognosis prediction in patients with NSCLC.