circ_0005273 promotes thyroid carcinoma progression by SOX2 expression.

Papillary thyroid carcinoma (PTC) is one of the most prevalent tumors in endocrine system. CircRNAs (circular RNAs) are widely known as critical regulators in tumorigenesis of papillary thyroid carcinoma (PTC). The present study focused on the functional investigation and potential molecular mechanism toward circ_0005273 in PTC progression. Gene Expression Omnibus datasets (GSE93522) and qRT-PCR (quantitative real-time PCR) analyses showed that circ_0005273 were upregulated in PTC tissues and cell lines. Moreover, circ_0005273 was located in the cytoplasm of PTC cells and suggested poor prognosis in PTC patients. In vivo and in vitro functional assays indicated that knockdown of circ_0005273 inhibited PTC tumor growth and progression, respectively. Mechanistically, miR-1183 was identified as functional target of circ_0005273, and circ_0005273 could directly bind to miR-1138 and relieve inhibition of SRY (sex-determining region Y)-box 2 (SOX2). Data from Cell Counting Kit-8, colony formation assays and transwell assays revealed that the oncogenic role of circ_0005273 on PTC progression dependent on miR-1183-mediated SOX2 expression. In conclusion, circ_0005273 functioned as a tumor promoter of PTC via circ_0005273/miR-1183/SOX2 axis, suggesting a novel biomarker and therapeutic target for PTC.