Downregulation of circ-SFMBT2 blocks the development of gastric cancer by targeting the miR-885-3p/CHD7 pathway

Abstract

Accumulating evidence insists that circular RNAs (circRNAs) play important roles in the development of human cancers, including gastric cancer. This study aimed to investigate the role of circ-SFMBT2 and provide a potential mechanism to explain its function. The expression of circ-SFMBT2, miR-885-3p and chromodomain-helicase-DNA-binding protein 7 (CHD7) mRNA was determined by quantitative real-time PCR (qRT-PCR), and the protein level of CHD7 was determined by western blot. To investigate the function of circ-SFMBT2 in vitro, the effects of circ-SFMBT2 on cell viability, colony formation, apoptosis, migration and invasion were assessed using cell counting kit-8 assay, colony formation assay, flow cytometry assay, wounding healing assay and transwell assay, respectively. The indicators of oxidative stress were assessed using matched kits. Besides, the function of circ-SFMBT2 was also investigated in animal models. The relationship between miR-885-3p and circ-SFMBT2 or CHD7 was verified by dual-luciferase reporter assay and RNA immunoprecipitation assay. Circ-SFMBT2 and CHD7 were upregulated, whereas miR-885-3p was downregulated in gastric cancer tissues and cells. In functional assay, circ-SFMBT2 knockdown suppressed gastric cancer cell viability, colony formation ability, migration, invasion and oxidative stress but induced apoptosis, and circ-SFMBT2 downregulation also blocked tumor growth in vivo. In mechanism analysis, circ-SFMBT2 regulated CHD7 expression by sponging its target miRNA, miR-885-3p. Rescue experiments manifested that miR-885-3p inhibition reversed the effects of circ-SFMBT2 knockdown, and CHD7 overexpression abolished the antitumor role of miR-885-3p overexpression. Moreover, circ-SFMBT2 knockdown inactivated the Wnt/β-catenin signaling pathway. Circ-SFMBT2 downregulation repressed the development of gastric cancer partially by controlling the miR-885-3p/CHD7 axis, which might be a novel strategy to inhibit gastric cancer progression.