CircEIF4G2 Promotes Tumorigenesis and Progression of Osteosarcoma by Sponging miR-218

Circular RNAs (circRNAs) play a key role in regulating the tumorigenesis and development of human cancers, including osteosarcoma (OS). Of note, the molecular mechanism underlying the progression of OS has remained largely unclear. The present study identified that a novel circRNA circEIF4G2 was upregulated in OS tissues and cells. Moreover, we constructed a circEIF4G2-mediated ceRNA network and revealed that circEIF4G2 was involved in regulating multiple cancer pathways, such as the EGFR signaling pathway, the PI3K-Akt signaling pathway, and the ErbB signaling pathway. Loss-of-function assays showed that circEIF4G2 knockdown significantly suppressed OS cell proliferation, migration, and invasion. Mechanically, we found that circEIF4G2 could directly bind to miR-218, and miR-218 mediated the effect of circEIF4G2 knockdown on OS progression. In conclusion, the present study showed that circEIF4G2 could be a potential biomarker for OS.