Downregulation of circDYNC1H1 exhibits inhibitor effect on cell proliferation and migration in hepatocellular carcinoma through miR‐140‐5p

Abstract Circular RNAs have been found to be aberrantly expressed in tumors and their significance in tumorigenesis has been focused on. The role of circDYNC1H1 in hepatocellular carcinoma (HCC) pathogenesis and its relationship with miR‐140‐5p were explored. The expression of circDYNC1H1, miR‐140‐5p, and SULT2B1 in HCC tissues and cells was measured, and Pearson's analysis was used to analyze their expression correlation. 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide and Transwell assays were performed to determine cell proliferation and migration. Binding between circDYNC1H1 and miR‐140‐5p was evaluated with RNA pull‐down assay. A luciferase reporter assay was conducted to assess the interaction between circDYNC1H1 and miR‐140‐5p and between miR‐140‐5p and SULT2B1. circDYNC1H1 was highly expressed in HCC tissues ( n = 20), and it was negatively associated with the expression of miR‐140‐5p but positively correlated with SULT2B1 messenger RNA expression. circDYNC1H1 was upregulated in cell lines of HCC. Interference of circDYNC1H1 suppressed cell proliferation and migration of HCC. circDYNC1H1 acted as a sponge of miR‐140‐5p. miR‐140‐5p controlled SULT2B1 expression by targeting its 3′‐untranslated region. circDYNC1H1 enhanced SULT2B1 expression via sponging miR‐140‐5p. Downregulation of circDYNC1H1 disturbed cell proliferation and migration of HCC through miR‐140‐5p/SULT2B1 pathway. Silencing of circDYNC1H1 delayed tumor growth in HCC mouse model. Acting like a sponge of miR‐140‐5p, silenced circDYNC1H1 downregulated SULT2B1 to restrain HCC cell proliferation and migration, which is adverse to HCC growth and progression.