Circular RNA circTADA2A promotes the proliferation, invasion, and migration of non-small cell lung cancer cells via the miR-450b-3p/ HMGN5 signaling pathway

Background: Circular RNAs (circRNAs) have been confirmed to exert important roles in promoting tumor initiation and progression. However, the expression, effect, and underlying mechanism of circTADA2A in non-small cell lung cancer (NSCLC) remain unclear. Methods: A total of 60 paired clinical samples of NSCLC tissues and corresponding normal adjacent tissues were obtained. Quantitative real-time PCR was used to verify circTADA2A, miR-450b-3p, and HMGN5 mRNA expression. The NSCLC cell Lines A549 and H1299 were individually transfected with circTADA2A and HMGN5. The regulatory interaction between circTADA2A and miR-450b-3p was investigated by dual-luciferase reporter assay. HMGN5 protein expression was detected by Western blotting. Results: CircTADA2A expression was significantly upregulated and correlated with poor overall survival of NSCLC patients. Functionally, circTADA2A inhibition successfully suppressed the proliferation, invasion, and migration of A549 and H1299 cells. circTADA2A functioned as a competing endogenous RNA to sponge miR-450b-3p to promote the expression of HMGN5 mRNA and protein. Furthermore, a positive relationship between circTADA2A and HMGN5 existed in NSCLC tissues. There were negative relationships between circTADA2A and miR-450b-3p as well as miR-450b-3p and HMGN5 in NSCLC tissues. Conclusions: These findings suggest that circTADA2A might act as an oncogenic circRNA that promotes NSCLC progression by sponging miR-450b-3p and promoting HMGN5 expression, indicating that the suppression of circTADA2A could become a potential therapeutic target for restraining NSCLC.