Function And Mechanism Of Long Non-coding RNA LPP-AS2 In Glioma

Purpose: Glioma is the most common primary malignant intracranial tumor in adults and has a poor clinical prognosis.More and more evidences show that long non-coding RNA(lncRNA)plays an important regulatory role in cancer processes including glioblastoma.In this study,we identified a new lncRNA LPP antisense RNA-2(LPP-AS2)and studied its function and mechanism in the occurrence and development of glioma.Methods: High-throughput RNA sequencing was performed to identify differentially expressed lncRNA and m RNA in 3 pairs of glioma tissues and 3 pairs of normal brain tissues.Real-time fluorescent quantitative PCR(RT-q PCR)technology was used to detect the expression levels of LPP-AS2,epidermal growth factor receptor(EGFR)and mi R-7-5p in glioma tissues and glioma cell lines.Using si RNA and overexpression plasmid to change the expression level of lncRNA LPP-AS2 in U251 and SHG44 cell lines.CCK-8 assay was used to verify the effect of lncRNA LPP-AS2 on the proliferation activity of glioma cells;Transwell assays were performed to verify the invasion of glioma cells;scratch test was used to verify the change in migration ability of glioma cells,and flow cytometry assay was used to detect the change in apoptosis ability of glioma cells.Through bioinformatics analysis,dual luciferase reporter gene assay,RNA pull-down assay,RNA immunoprecipitation(RIP)and rescue experiments to explore the potential mechanism of competitive endogenous RNA(ce RNA).Results: The result of high-throughput RNA sequencing showed that lncRNA LPP-AS2 was significantly upregulated in glioma tissues.Real-time fluorescent quantitative PCR(RT-q PCR)further confirmed the expression of LPP-AS2 in gliomas.The expression level of lncRNA LPP-AS2 was significantly related to the poor prognosis of patients with glioma.Downregulation of LPP-AS2 could significantly inhibit the proliferation,invasion abilities and promote apoptosis of glioma cells,and the results of in vivo experiments also showed that downregulation of LPP-AS2 could inhibit the occurrence and development of glioma.Subsequently,we observed that LPP-AS2 was related to EGFR in the co-expression network.A rescue experiment found that LPP-AS2 regulates EGFR expression by sponging mi R-7-5p as ce RNA in glioma cells and further affected PI3K/AKT signaling pathway.In addition,the results of chromatin immunoprecipitation experiments showed that c-MYC directly binds to the promoter region of LPP-AS2.As a downstream protein of EGFR,c-MYC was regulated by LPP-AS2 and further enhanced the expression of LPP-AS2.LncRNA LPP-AS2 promoted the occurrence of glioma through the mi R-7-5p/EGFR/PI3K/AKT/c-MYC feedback loop.Conclusion:(1)LncRNA LPP-AS2 was highly expressed in glioma tissues.Knockdown of LPP-AS2 expression could significantly inhibit the proliferation,invasion and clonal formation abilities of glioma cells,and promote cell apoptosis.It also indicated that the lncRNA LPP-AS2 played an important role in the biological development of glioma.(2)LncRNA LPP-AS2 could competitively bind to EGFR m RNA with mi R-7-5p,thereby regulating the expression of downstream c-MYC protein,and c-MYC protein could reversely enhance the expression of LPP-AS2.(3)LncRNA LPP-AS2 exerted a tumorigenic effect through a new molecular pathway in glioma,and might be a potential target for the diagnosis,treatment and prognosis of glioma.