CircRNA PTPRM Promotes Non-Small Cell Lung Cancer Progression by Modulating the miR-139-5p/SETD5 Axis

Introduction: Circular RNAs (circRNAs) are important regulators in various cancers, especially hepatocellular carcinoma. However, the role of circ RNA PTPRM (circPTPRM) in the development of non-small-cell lung cancer (NSCLC) remains unclear. Methods: We collected 26 clinical specimens (corresponding to 26 normal lung tissues) of lung adenocarcinoma and the expression of mir-139-5p and circPTPRM were first detected. Cell proliferation was detected by EdU method, invasion/migration ability of cells was evaluated by transwell method. And the correlation between circPTPRM and mir-139-5p was detected by luciferase reporter gene and RNA pull-down assay. Finally, we verified our hypothesis with BALB/c nude mice. Results: Through bioinformatics software, we found that circPTPRM was negatively correlated with mir-139-5p, and then we used human adenocarcinoma tissue samples to further verify their relationship and get the same result. EdU method, transwell method, and luciferase assay, RNA pull-down assay were applied, and the results show that the knockdown of circPTPRM inhibit proliferation, migration, and invasion of cells can be reversed by mir-139-5p inhibitor. Next, we used Starbase v2.0 to identify the target site of miR-139-5p and focused on SET domain containing 5 (SETD5). We derive the hypothesis by verifying the relationship between miR-139-5p and SETD5 that circPTPRM may interact with miR-139-5p/SETD5 axis. At last, we evaluated the effects of circPTPRM, SETD5, and miR-139-5p on tumor growth in vivo using BALB/c nude mice to prove the hypothesis. Conclusion: We thus conclude that circPTPRM promotes the progression of NSCLC by regulating the miR-139-5p/SETD5 axis.