Circ_0000370 Plays an Oncogenic Role in Colorectal Cancer by Regulating the miR-502-5p/SIRT1 Axis.

The importance of circular RNA has been reported in cancer development. However, the role and mechanism of circ_0000370 in CRC progression are still unclear. Quantitative real-time PCR and Western blot assay were performed to measure RNA and protein expression. Cell proliferation was assessed by cell colony formation assay and 5-Ethynyl-2'-deoxyuridine assay. Flow cytometry was used to measure cell apoptosis. Cell migration and invasion were detected by transwell assay. The intermolecular target relations between miR-502-5p and circ_0000370 or SIRT1 were confirmed by dual-luciferase reporter assay and RNA immunoprecipitation assay. A xenograft tumor model was established to examine the role of circ_0000370 in tumor growth in vivo. As compared with controls, the expression of circ_0000370 was upregulated in CRC tissues and cells. Circ_0000370 depletion inhibited CRC cell proliferation, migration and invasion but induced cell apoptosis. Meanwhile, circ_0000370 depletion restrained tumor growth in vivo. In addition, miR-502-5p inhibitor partly reverted the impacts of circ_0000370 knockdown on CRC cells. Moreover, miR-502-5p mimic-caused effects on cell phenotypes were attenuated by SIRT1 overexpression. Circ_0000370 induced the proliferation and metastasis of CRC cells by sponging miR-502-5p and enhancing SIRT1 expression, which provided a possible target for CRC treatment.