circPVT1 promotes osteosarcoma glycolysis and metastasis by sponging miR-423-5p to activate Wnt5a/Ror2 signaling

Abstract

Osteosarcoma (OS) is the most prevalent form of bone cancer. It has a high metastatic potential and progresses rapidly. The molecular mechanisms of OS remain unclear and this study aims to examine the functional role of circPVT1 and miR-423-5p in OS. Quantitative RT-PCR (qRT-PCR) and western blotting were used to examine levels of miR-423-5p, circPVT1, Wnt5a, Ror2, and glycolysis-related proteins, including HK2, PKM2, GLUT1, and LDHA. Colony formation and transwell assays were used to test the roles of miR-423-5p, circPVT1, and Wnt5a/Ror2 in OS cell proliferation, migration, and invasion. Dual luciferase assay and Ago2-RIP were used to validate the interactions of miR-423-5p/Wnt5a, miR-423-5p/Ror2, and circPVT1/miR-423-5p. Glucose uptake assay and measurement of lactate production were performed to assess the glycolysis process. A nude mouse xenograft model was used to evaluate the effects of sh-circPVT1 and miR-423-5p mimics on tumor growth and metastasis in vivo. miR-423-5p was reduced in both OS tissues and OS cell lines, while Wnt5a/Ror2 and circPVT1 were elevated. miR-423-5p bound to 3′-UTR of Wnt5a and Ror2 mRNA, and inhibited glycolysis and OS cell proliferation, migration, and invasion by targeting Wnt5a and Ror2. circPVT1 interacted with miR-423-5p and activated Wnt5a/Ror2 signaling by sponging miR-423-5p. Knockdown of circPVT1 or overexpression of miR-423-5p suppressed OS tumor growth and metastasis in vivo. miR-423-5p inhibited OS glycolysis, proliferation, migration, and metastasis by targeting and suppressing Wnt5a/Ror2 signaling pathway, while circPVT1 promoted those processes by acting as a sponge of miR-423-5p.