CircSAMD4A accelerates cell proliferation of osteosarcoma by sponging miR-1244 and regulating MDM2 mRNA expression

Here, we firstly examined the proliferation and invasion capacities of different osteosarcoma (OS) cell lines, and analyzed the profiling of the differentially expressed circular RNAs(circRNAs). Then, we identified a novel circRNA(circ_101356/circ_0004846, we named circSAMD4 in the present study) and found it was highly expressed in the OS tissues compared to adjacent non -cancerous tissues. Furthermore, we indicated that circSAMD4A promoted OS proliferation in vivo and in vitro. In addition, we proved that circSAMD4A enhances osteosarcoma cells sternness features. In mechanism, circSAMD4A could sponge miR-1244 in OS cells. Moreover, we verified that MDM2 was a target of miR-1244. In conclusion, circSAMD4A/miR-1244/MDM2 regulatory loop might be a promising therapeutic target for OS treatment. (C) 2019 Published by Elsevier Inc.