LINC00266-1/miR-548c-3p/SMAD2 feedback loop stimulates the development of osteosarcoma

Osteosarcoma (OS) is one of the most common primary bone malignancies and accounts for 3.4% of pediatric tumors. Its 5-year survival is as low as about 20%. Differentially expressed lncRNAs in OS profiling were searched in the downloaded profile of GSE12865. As a result, LINC00266-1 was detected to be upregulated in both GSE12865 and OS tissues we collected. SMAD2 was the downstream target binding to promoter sites of LINC00266-1, displaying a positive regulatory interaction. Knockdown of LINC00266-1 suppressed the proliferative and metastatic abilities, and promoted the apoptosis in OS cells. Besides, knockdown of LINC00266-1 significantly alleviated the growth of OS in vivo. MiR-548c-3p was the sponge miRNA of LINC00266-1, which was able to reverse the regulatory effects of LINC00266-1 on OS cell phenotypes. Moreover, miR-548c-3p bound to the 3′-UTR of SMAD2 and thus downregulated SMAD2. Overexpression of SMAD2 partially reversed the regulatory effects of LINC00266-1 on OS cell phenotypes. Finally, we have identified that LINC00266-1/miR-548c-3p/SMAD2 feedback loop was responsible for stimulating the development of OS.