Hsa_circ_0003176 Suppresses the Progression of Non-Small-Cell Lung Cancer Via Regulating MiR-182-5p/RBM5 Axis

Background: Non-small-cell lung cancer (NSCLC) is one of the major diseases that threaten human health, and there is still no fundamental treatment method. Emerging evidences suggested that circRNAs might be an effective target to treatment NSCLC. However, the roles and detailed mechanisms of hsa_circ_0003176 in NSCLC still not clear.

Methods: hsa_circ_0003176 was identified from GSE101684 and GSE112214 datasets of Gene Expression Omnibus (GEO) database. The expression of hsa_circ_0003176 was detected by RT-qPCR in NSCLC tissues, paired adjacent nontumor tissues, and cell lines. RNA fluorescence in situ hybridization and nuclear and cytoplasmic RNA fractionation analysis was used to detect the subcellular localization of hsa_circ_0003176 in H1299 and A549 cells. Dual-luciferase reporter and RNA pull-down assay were used to confirm the regulatory of miR-182-5p to hsa_circ_0003176 and RBM5. The roles of hsa_circ_0003176 in NSCLC progression was evaluated both in vitro by CCK-8 assay, colony formation assay, wound-healing assay, and matrigel transwell assay and in vivo by the subcutaneous xenograft nude mouse experiment and lung metastasis nude mouse experiment. In addition, RNA pull down and luciferase reporter assays were carried out to investigate the interaction between hsa_circ_0003176 or RBM5 and miR-182-5p.

Results: Our results indicated that hsa_circ_0003176 showed typical characteristic of circRNAs, which was downregulated in both NSCLC tissues and cell lines. Functionally, overexpression of hsa_circ_0003176 suppressed the proliferation, migration, and invasion of NSCLC cells in vitro and inhibited NSCLC growth and metastasis in vivo. Furthermore, we found that hsa_circ_0003176 acts as sponge of miR-182-5p to regulate RBM5 expression. Further, in vitro rescue experiments demonstrated that hsa_circ_0003176 suppressed the proliferation, migration, and invasion of NSCLC cells by regulating miR-182-5p/RBM5 axis.

Conclusion: We demonstrated that hsa_circ_0003176 suppressed the NSCLC progression via regulating miR-182-5p/RBM5 axis. These data indicated that hsa_circ_0003176 might be a novel molecular target for NSCLC treatment.