Circ_0004140 promotes lung adenocarcinoma progression by upregulating NOVA2 via sponging miR‐330‐5p

Abstract

AbstractBackgroundCircular RNAs (circRNAs) play a significant role in the tumorigenesis and progression of diverse human cancers, including lung adenocarcinoma. A previous study suggested that circ_0004140 expression was increased in lung adenocarcinoma cells. However, the molecular mechanism of circRNA circ_0004140 involved in lung adenocarcinoma is poorly defined.MethodsCirc_0004140, microRNA‐330‐5p (miR‐330‐5p), and NOVA alternative splicing regulator 2 (NOVA2) expression were determined by real‐time quantitative polymerase chain reaction (RT‐qPCR). Cell proliferation, apoptosis, migration, invasion, and angiogenesis ability were assessed using 5‐ethynyl‐2’‐deoxyuridine (EdU), flow cytometry, wound healing, transwell, and capillary‐like network formation assays. Proliferating cell nuclear antigen (PCNA), cyclin D1, and NOVA2 protein levels were detected using Western blot assay. The interaction between miR‐330‐5p and circ_0004140 or NOVA2 was verified by dual‐luciferase reporter assay. Xenograft tumor model was utilized to assess the role of circ_0004140 in tumor growth in vivo.ResultsCirc_0004140 was upregulated in lung adenocarcinoma tissues and cell lines. Circ_0004140 silencing suppressed cell proliferation, migration, invasion and tube formation ability, and triggered the apoptosis of lung adenocarcinoma cells. Circ_0004140 acted as a molecular sponge for miR‐330‐5p, and miR‐330‐5p silencing largely reversed circ_0004140 knockdown‐induced effects in lung adenocarcinoma cells. NOVA2 was a target of miR‐330‐5p, and NOVA2 overexpression might largely overturn miR‐330‐5p overexpression‐induced influences in lung adenocarcinoma cells. Circ_0004140 upregulated NOVA2 expression via sponging miR‐330‐5p in lung adenocarcinoma cells. Circ_0004140 silencing restrained xenograft tumor growth in vivo.ConclusionCirc_0004140 knockdown might suppress the malignant biological behaviors of lung adenocarcinoma cells via miR‐330‐5p‐dependent regulation of NOVA2.