[Identification and functional characterization of circular RNAs in the liver of whitespotted bamboo shark (Chiloscyllium plagiosum)].

This study aims to identify the circular RNAs (circRNAs) in the liver of whitespotted bamboo shark (Chiloscyllium plagiosum) and to explore the effect of the overexpression of circRNAs on the proliferation and migration of hepatocellular carcinoma HepG2 cells. We conducted high-throughput sequencing for prediction of the circRNAs and then designed forward and reverse primers to verify them. Further, we constructed overexpression vectors for transient transfection of circRNAs into HepG2 cells. Finally, we employed CCK-8 assay and scratch assay to measure the proliferation and migration of the treated HepG2 cells. A total of 4 558 circRNAs were predicted, among which 14 circRNAs were confirmed. The qRT-PCR showed that circRNA 13-566, circRNA 4-475, circRNA 5-402, circRNA 294-177, and circRNA 30-219 were transiently overexpressed in HepG2 cells. The overexpression of these five circRNAs inhibited the proliferation and migration of HepG2 cells to varying degrees, and circRNA 4-475 and circRNA 294-177 had especially notable effect. This study provided a basic database of circRNA genes that particularly active in whitespotted bamboo shark liver and demonstrated with functional studies of these circRNAs potentially involved in normal and malignant liver cells.