Elevation of circular RNA circ_0005230 facilitates cell growth and metastasis via sponging miR-1238 and miR-1299 in cholangiocarcinoma

Cholangiocarcinoma (CCA) is a highly malignant carcinoma with high mortality rate worldwide. Emerging evidence indicates that aberrantly expressed circular RNAs (circRNAs) functions crucial roles in tumor progression. In this work, we focused on a novel circRNA, circ_0005230, in carcinogenesis and development of CCA. Circ_0005230 levels in CCA specimens and cells were measured by qRT-PCR. The clinical implication of circ_0005230 was analyzed by fisher’s exact test. Gain/loss of-function assays were conducted to reveal the effects of circ_0005230 on the cell proliferation, apoptosis, migration and invasion of CCA cells. Xenograft and lung metastatic models were constructed to confirm the in vitro data. Dual luciferase reporter and rescue assays were carried out to illuminate the mechanism behind the regulatory actions. As data showed, circ_0005230 was elevated in tumors and CCA cells. Its expression in tumor samples was related to clinical severity. Functionally, circ_0005230 significantly facilitated cell growth, clone-forming ability and metastatic properties and inhibit cell apoptosis in CCA cells. The in vivo study further validated the in vitro results. However, knockdown of circ_0005230 did not affect normal biliary epithelial (HIBEC) cell growth and apoptosis. For the mechanism investigation, circ_0005230 could directly sponge miR-1238 and miR-1299 to exert its oncogenic functions. Overall, this work showed that circ_0005230 might act as an effective therapeutic target for CCA.