Circ-AASDH functions as the progression of early stage lung adenocarcinoma by targeting miR-140-3p to activate E2F7 expression

BACKGROUND: Lung adenocarcinoma (LUAD), which is the most common subtype of non-small cell lung cancer, is a leading course of cancer-related mortality worldwide. Recently, circular RNA (CircRNAs) has become a hot spot in cancer research because of its important role in tumorigenesis and development and its superior stability. This study aims to clarify the role of circ-AASDH in LUAD and explore its competitive endogenous RNA mechanism. METHODS: The circ-AASDH, miR-140-3p and E2F transcription factor 7 (E2F7) mRNA expression levels were detected via qRT-PCR. CCK-8 and colony formation assay were used to evaluate the ability of cell proliferation. Transwell assay and wound healing assay were performed to measure the invasion and migration ability. Flow cytometry was used to detect the apoptosis of cells. Moreover, Sanger sequencing, RNaseR treatment and divergent primers were used to verify the circular structure. Luciferase reporter and RNA pull-down experiment were performed to characterize the ceRNA mechanism of circ-AASDH. The xenograft model of mice was established to investigate the tumorigenicity of circ-AASDH to LUAD in vivo. RESULTS: By screening for differentially expressed circRNAs, we found that circ-AASDH was highly expressed in LUAD tissues and cells and correlated with tumor size, clinical stage and poor prognosis. Transfection of si-circ-AASDH can inhibit the proliferation and migration of LUAD cells and promote apoptosis in vitro. In mechanism, circ-AASDH could be used as a sponge of miR-140-3p to weaken its inhibition on the expression of E2F7. Additionally, the overexpression of circ-AASDH could deduce the suppression of miR-140-3p on the malignant progression of LUAD cells. Besides, silencing of circ-AASDH inhibited cell proliferation and migration by regulating the expression of E2F7. Furthermore, overexpression of circ-AASDH can promote the growth of LUAD in vivo. CONCLUSIONS: Circ-AASDH/miR-140-3p/E2F7 regulating axis promoted the progression in LUAD. Our results provided ideas for understanding the biological mechanism of circ-AASDH and clarify potential therapeutic targets in LUAD.