Abstract
CircRNAs have been implicated in the progression of human cancers, including papillary thyroid carcinoma (PTC). Although circ_0008274 has been demonstrated as a potential oncogenic circRNA in PTC, our understanding of its molecular determinants is limited. The levels of circ_0008274, miR-154-3p and solute carrier family 7 member 11 (SLC7A11) mRNA were determined by quantitative real-time polymerase chain reaction (qRT-PCR). SLC7A11 protein level was assessed by western blot. Cell apoptosis, migration, and adhesion capacities were examined by flow cytometry, transwell and cell adhesion assays, respectively. The targeted correlations among circ_0008274, miR-154-3p and SLC7A11 were confirmed by a dual-luciferase reporter assay. Animal studies were performed to observe the role of circ_0008274 in tumor growth in vivo. Our data showed that the high levels of circ_0008274 and SLC7A11 were associated with poor prognosis of PTC patients. The knockdown of circ_0008274 or SLC7A11 enhanced PTC cell apoptosis and repressed cell migration and adhesion in vitro. Circ_0008274 knockdown suppressed tumor growth in vivo. Mechanistically, circ_0008274 modulated SLC7A11 expression by acting as a sponge of miR-154-3p. SLC7A11 was a functional mediator of circ_0008274 in regulating PTC cell apoptosis, migration and adhesion in vitro, and miR-154-3p overexpression repressed PTC progression in vitro by targeting SLC7A11. Our findings identified that the knockdown of circ_0008274 repressed PTC malignant progression at least in part through regulating the miR-154-3p/SLC7A11 axis, providing a promising therapeutic opportunity for PTC treatment.