Circular RNA circ_0000517 Facilitates The Growth and Metastasis of Non-Small Cell Lung Cancer by Sponging miR-326/miR-330-5p

OBJECTIVE: There is growing evidence showing that circular RNAs (circRNAs) are crucial regulators in modulating the biological behavior of tumors. This work is aimed to probe the role of circ_0000517 in non-small cell lung cancer (NSCLC) and to elucidate its mechanism of action. MATERIALS AND METHODS: In this experimental study, the differentially expressed circRNAs in NSCLC were screened using the GEO database (GSE158695). Circ_0000517, miR-326, miR-330-5p, and MMP2 expression levels were determined by quantitative real-time polymerase chain reaction (qRT-PCR) analysis and Western blot. The proliferation, apoptosis, migration, and invasion of NSCLC cells were detected by CCK-8, flow cytometry, and transwell assays. RNA immunoprecipitation (RIP), RNA pull-down, and dual-luciferase reporter gene assays were performed to clarify the association between the circ_0000517 and miR-326/miR-330-5p. RESULTS: Circ_0000517 was shown to be up-regulated in NSCLC tissues and cell lines. The up-regulation of circ_0000517 is closely associated with advanced clinical stage of cancer, lymph node metastasis, and poor prognosis in NSCLC patients. Circ_0000517 knockdown impeded the proliferation, migration, and invasion of NSCLC cells and enhanced their apoptosis. Mechanistically, circ_0000517 was demonstrated to up-regulate MMP2 expression via decoying miR-326 and miR-330-5p to facilitate the malignant biological behaviors of NSCLC cells. CONCLUSION: This work reveals that circ_0000517 is implicated in NSCLC cell growth and metastasis through the modulation of miR-326/miR-330-5p/MMP2, providing novel insights into the role of circRNAs in NSCLC progression.