Circ-NT5C2 stimulates FZD4 expression to promote the malignant progression of osteosarcoma by targeting miR-488-3p

Abstract

BackgroundCirc-NT5C2 has been confirmed to be highly expressed and associated to the progression of osteosarcoma (OS). However, the behind mechanism of circ-NT5C2 involvement in OS remains unclear.MethodsThe expression of circ-NT5C2, miR-488-3p and FZD4 was measured by quantitative real-time PCR, and the protein expression of E-cadherin, N-cadherin and FZD4 was detected by western blot. Cell counting kit 8 assay, colony formation assay and 5-ethynyl-2-deoxyuridine assay were performed to assess the cell proliferation. The cell apoptosis was measured by flow cytometry and Caspase3/Caspase9 Activity Assay Kits. Cell migration and invasion were detected by transwell assay. Dual-luciferase reporter assay and RIP assay were carried out to determine the binding relation among circ-NT5C2, miR-488-3p and FZD4. Animal experiment and immunohistochemistry analysis were conducted to explore the role of circ-NT5C2 in tumor growth in vivo.ResultsComparing with controls, the expression of circ-NT5C2 and FZD4 was upregulated and miR-488-3p expression was downregulated in OS tumor tissues and cells. Circ-NT5C2 overexpression facilitated the cell proliferation and motility and induced cell apoptosis of OS cells, whereas circ-NT5C2 knockdown had the opposite effect. Besides, we also found and confirmed that circ-NT5C2 regulated cell malignant behaviors via modulating miR-488-3p/FZD4 axis in OS. Moreover, circ-NT5C2 silencing repressed the growth of xenografts in vivo.ConclusionCirc-NT5C2 upregulated FZD4 expression via sponging miR-488-3p, thus facilitating cell malignant behaviors in OS.