Circ-XPO1 upregulates XPO1 expression by sponging multiple miRNAs to facilitate osteosarcoma cell progression.

Circular RNAs (circRNAs) act as a key role in mediating carcinogenesis. Nevertheless, the functions and mechanisms of circRNAs in osteosarcoma (OS) are still not fully understood. In the present study, we aim to investigate the functions of circ-XPO1 in OS and its potential mechanism underlying OS progression. CircRNA microarray indicated elevation of circ-XPO1 in OS specimens relative to normal samples. Elevation of circ-XPO1 and XPO1 mRNA was identified in OS tissue specimens and cells by qRT-PCR. In addition, enhanced expression of circ-XPO1 and XPO1 mRNA both correlated with poor prognosis for the patients with OS, as estimated by Kaplan-Meier analysis. Functionally, circ-XPO1 and XPO1 both facilitated the growth and invasion and decreased the apoptosis of OS cells. Moreover, we constructed the circ-XPO1-miRNAs-XPO1 3'-UTR interaction network and verified that circ-XPO1 could sponge miR-23a-3p, miR-23b-3p, miR-23c, and miR-130a-5p to regulate XPO1 expression. Furthermore, rescue assay indicated that the effect of circ-XPO1 on cell progression was partly relying on these miRNAs. Taken together, we found that circ-XPO1 regulated the expression of XPO1 through sponging miRNAs as a competing endogenous (ceRNA), providing the possibility that circ-XPO1 might play as a new therapeutic target for OS.