Circular RNA circ_0001649 acts as a prognostic biomarker and inhibits NSCLC progression via sponging miR-331-3p and miR-338-5p

Accumulating evidence documented the key functions of circular RNAs (circRNAs) in various malignancies. However, the study regarding the involvement of circRNAs in non-small cell lung cancer (NSCLC) has just begun. In the present study, qRT-PCR was used to determine the expression of circ_0001649 in NSCLC tissues and cells. Its clinical significance was further assessed by Fisher's exact test, Kaplan-Meier analysis and Cox regression model. Additionally, loss-of-function and gain-of-function experiments were carried out to detect the functional role of circ_0001649 in cell proliferation, migration and invasion. Furthermore, animal study was performed to confirm the in vitro results. Importantly, luciferase reporter assay was induced to reveal the underlying mechanism of circ_0001649. As a result, circ_0001649 was decreased in NSCLC tissues and cells and this downregulation is correlated with advanced TNM stage, positive lymph node metastasis and unfavorable prognosis. Additionally, circ_0001649 inhibited cell growth and metastasis both in vitro and in vivo. In mechanism, circ_0001649 was identified as the sponge of miR-331-3p and miR-338-5p. Moreover, the biological functions of circ_0001649 is partly dependent on its regulation on miR-331-3p and miR-338-5p. Collectively, this study suggested that circ_0001649/miR-331-3p/miR-338-5p regulatory signaling might be a potential target for NSCLC therapy. (C) 2018 Elsevier Inc. All rights reserved.