The role of LINC01419 in regulating the cell stemness in lung adenocarcinoma through recruiting EZH2 and regulating FBP1 expression

Background: Recent years have witnessed a growing academic interest in the effects of lncRNAs on tumors. LINC01419 is found to facilitate proliferation and metastasis of lung adenocarcinoma (LUAD) cells, but there is a great deal of uncertainty about how LINC01419 works on LUAD cell stemness. For this reason, the focus of this research is centered on the regulatory impact of LINC01419 on LUAD cell stemness.

Methods: For the detection of the expression level of LINC01419 in LUAD, qRT-PCR was performed. And how oe-LINC01419 and sh-LINC01419 affected LUAD cell proliferation as well as stem cell sphere-formation were examined by CCK-8 and cell sphere-forming assays. In addition, whether LINC01419 could recruit EZH2 and regulate FBP1 expression were determined by bioinformatics analysis, RNA immunoprecipitation (RIP), and chromatin immunoprecipitation (ChIP). Western blot was utilized to detect the protein expression levels of FBP1, CD44, CD133, and ALDH-1 as well.

Results: On the basis of the findings from those assays, an up-regulation of LINC01419 level was demonstrated in LUAD cell lines, and a remarkable upregulation of it in CD44 + LUAD cells. In LUAD cells, proliferation and stem cell sphere-formation that were attenuated by LINC01419 knockdown were discovered to be facilitated by LINC01419 overexpression. And a binding relationship between LINC01419 and EZH2 was determined by RIP assay. Besides, EZH2 was capable of binding to FBP1 promoter region, as found by ChIP-PCR assay. Finally, it was demonstrated by in vitro experiments that LINC01419 could inhibit FBP1 expression by recruiting EZH2, resulting in promotion of LUAD cell proliferation and stemness.

Significance: To summarize, our findings demonstrate a cancer-promoting role of LINC01419 in LUAD. LINC01419, by recruiting EZH2 and regulating FBP1 expression, contributes to LUAD cell stemness. According to these findings, the potential of LINC01419 to be the target for LUAD treatment is hence determined, which also adds more possibility to the enrichment of therapeutic strategies for lung cancer stem cells.