LncRNA SOX2 overlapping transcript acts as a miRNA sponge to promote the proliferation and invasion of Ewing’s sarcoma

Long non-coding RNAs (lncRNAs) function as critical regulator in human cancers. However, the biological regulatory mechanisms of lncRNAs in Ewing’s sarcoma are still elusive. This study tries to investigate the clinical significance and pathological role of lncRNA SOX2 overlapping transcript (SOX2OT) in Ewing’s sarcoma progression. SOX2OT was identified to be up-regulated in Ewing’s sarcoma tissue and cells. In vitro, SOX2OT knockdown suppressed Ewing’s sarcoma cells proliferation and invasion, and triggered apoptosis. In vivo xenograft assays, SOX2OT knockdown significantly inhibited Ewing’s sarcoma growth. With the help of bioinformatics analysis and luciferase assay, SOX2OT was validated to harbor miR-363, acting as miRNA sponge or competing endogenous RNA (ceRNA). Furthermore, FOXP4 was validated to be the target protein of miR-363. Western blot and RT-PCR confirmed that SOX2OT was positively correlated with FOXP4 protein via sponging miR-363, forming a negative cascade regulation. In conclusion, our study realizes that SOX2OT acted as oncogene in the tumorigenesis of Ewing’s sarcoma, suggesting the SOX2OT/miR-363/FOXP4 pathway in Ewing’s sarcoma.