Circ-0012417/ miR-29c-5p Axis Stimulates Thyroid Cancer Growth

Abstract Background: There is an increasing tendency of the incidence rate of thyroid cancer. Despite the advance of widespread early diagnose and good prognosis of papillary thyroid cancer (PTC), some patients still suffered from the invasiveness and metastasis of thyroid cancer. More and more evidences demonstrated that circular RNAs (circRNAs) play important roles in tumorigenesis, tumor progression and metastasis. This study aims to identify oncogenic cirRNAs and explore its underlying molecular mechanisms in thyroid cancers.Methods: With circRNA chips in GEO database, we found that circ-0012417 was over-expressed in thyroid cancer. After silencing circ-0012417 or ectopic over-expressed circ-0012417, CCK-8 was used for detecting cell proliferation and transwell is used for examining metastasis and invasion abilities. Western Blot was used to detect changes of downstream proteins. Dual luciferase reporter assay was used to verify whether miR-29c-5p is the target of circ-0012417. Tumor xenografts in nude mice were used for further in vivo verifications. Results: Circ-0012417 is overexpressed in thyroid cancer, and silencing circ-0012417 could inhibit cancer cell proliferation, metastasis and invasion. MiR-29c-5p may be the target of circ-0012417 and inhibiting miR-29c-5p could reverse this phenomenon. And further analysis of TCGA and GTEx databases showed that EGFL7 may be the target of miR-126 and a promising thyroid cancer prognosis indicator.Conclusion: Circ-0012417 promotes thyroid cancer progression through regulating miR-29c-5p /EGFL7 pathway. Our finding provided novel therapeutic targets for thyroid cancer treatment.