Circ_0000376 regulates miR-577/HK2/LDHA signaling pathway to promote the growth, invasion and glycolysis of osteosarcoma

Many studies have confirmed that circular RNAs (circRNAs) mediate the malignant progression of various tumors including osteosarcoma (OS). Our study is to uncover novel molecular mechanisms by which circ_0000376 regulates OS progression. The expression of circ_0000376, microRNA (miR)-577, hexokinase 2 (HK2) and lactate dehydrogenase-A (LDHA) was determined by quantitative real-time PCR. OS cell proliferation, apoptosis and invasion were measured using cell counting kit 8 assay, colony formation assay, EdU assay, flow cytometry and transwell assay. Besides, cell glycolysis was assessed by testing glucose consumption, lactate production, and ATP/ADP ratios. Protein expression was examined by western blot analysis. The interaction between miR-577 and circ_0000376 or HK2/LADA was verified by dual-luciferase reporter assay. The role of circ_0000376 on OS tumor growth was explored by constructing mice xenograft models. Circ_0000376 had been found to be upregulated in OS tissues and cells. Functional experiments revealed that circ_0000376 interference hindered OS cell growth, invasion and glycolysis. Circ_0000376 sponged miR-577 to reduce its expression. In rescue experiments, miR-577 inhibitor abolished the regulation of circ_0000376 knockdown on OS cell functions. MiR-577 could target HK2 and LDHA in OS cells. MiR-577 suppressed OS cell growth, invasion and glycolysis, and these effects were reversed by HK2 and LDHA overexpression. Also, HK2 and LDHA expression could be regulated by circ_0000376. In vivo experiments showed that circ_0000376 knockdown inhibited OS tumorigenesis. Circ_0000376 contributed to OS growth, invasion and glycolysis depending on the regulation of miR-577/HK2/LDHA axis, providing a potential target for OS treatment.