Enhanced expression of circ_0000267 in hepatocellular carcinoma indicates poor prognosis and facilitates cell progression by sponging miR-646

Hepatocellular carcinoma (HCC) is a highly aggressive carcinoma worldwide. Circular RNAs (circRNAs) have been proved to be involved in the pathogenesis of several carcinomas. circ_0000267 was reported to be elevated in HCC tissue samples by circRNA microarray. In this study, quantitative reverse-transcription polymerase chain reaction was induced to further detect the expression of circ_0000267 in HCC tissues and cells. The clinical significance was also explored by Fisher's exact test, Kaplan-Meier curves and Cox regression analysis. Cell counting kit-8, colony formation, flow cytometry and transwell experiments were conducted on HCC cells to elucidate the functions of circ_0000267. Dual-luciferase reporter assay was induced to explore the mechanism of circ_0000267. Moreover, rescue experiments were also performed on HCC cells. As a result, circ_0000267 was enhanced in HCC tissues and cell lines. This upregulation is associated with patients' clinical severity and poor prognosis. Functionally, circ_0000267 could facilitate cell growth, migration and invasion and attenuate cell apoptosis in HCC cells. Mechanistically, circ_0000267 could directly sponge miR-646 to exert its oncogenic properties. In summary, we identified a novel HCC-associated circRNA in the progression of this fatal disease.