RESUMO
BACKGROUND: Increasing evidence suggests that circular RNA (circRNA) plays a regulatory role in the progression of renal cell carcinoma (RCC). However, the precise function and underlying mechanism of circSCNN1A in RCC progression still remain unclear. METHODS: The expression levels of circSCNN1A, microRNA-590-5p (miR-590-5p), claudin 8 (CLDN8), cyclin D1, matrix metalloprotein 2 (MMP2), MMP9, E-cadherin, N-cadherin and vimentin were detected by a quantitative real-time polymerase chain reaction and Western blotting analysis. Immunohistochemistry assay was performed to analyze the positive expression rate of CLDN8. Cell proliferation was investigated by cell colony formation, 5-Ethynyl-2'-deoxyuridine and DNA content quantitation assays. Cell migration and invasion were assessed by wound-healing and transwell invasion assays. Interactions among circSCNN1A, miR-590-5p and CLDN8 were identified by dual-luciferase reporter assay, RNA immunoprecipitation assay and RNA pull-down assay. Xenograft mouse model assay was conducted to verify the effect of circSCNN1A on tumor formation in vivo. RESULTS: CircSCNN1A and CLDN8 expression were significantly downregulated, while miR-590-5p was upregulated in both RCC tissues and cells. CircSCNN1A overexpression inhibited RCC cell proliferation, migration and invasion, accompanied by decreases of cyclin D1, MMP2, MMP9, N-cadherin and vimentin expression and an increase of E-cadherin expression. CircSCNN1A acted as a miR-590-5p sponge and regulated RCC cell processes by binding to miR-590-5p. CLDN8, a target gene of miR-590-5p, was involved in the regulation of the biological behaviors of RCC cells by miR-590-5p. In addition, circSCNN1A induced CLDN8 production by interacting with miR-590-5p. Further, circSCNN1A suppressed tumor formation in vivo. CONCLUSION: CircSCNN1A inhibited RCC cell proliferation, migration and invasion by regulating the miR-590-5p/CLDN8 pathway.