MicroRNA-336 directly targets Sox-2 in osteosarcoma to inhibit tumorigenesis

Previous evidence has suggested that microRNAs (miRNAs or miRs), which belong to a class of non-coding RNAs, shape cellular processes by regulating gene expression. Abnormal expression of miRNAs has been associated with tumorigenesis in multiple cancers. However, the function of miR-336 in osteosarcoma (OS) remains unknown. The experimental procedures used in the present study included flow cytometry, reverse transcription-quantitative polymerase chain reaction, luciferase reporter assay, invasion assay, western blot analysis and in vivo implantation. The results of the present study demonstrated that miR-336 may serve as a tumor suppressor in OS. Downregulation of miR-336 was observed in human OS specimens as well as OS cell lines. In addition, a significant negative correlation between sex determining region Y-box 2 (Sox-2) expression and miR-336 was demonstrated. miR-336 was confirmed to target the 3'-untranslated region of Sox-2 to inhibit proliferation, migration and invasion of OS cells. Consistently, restoration of Sox-2 expression counteracted the effect of miR-336, and recovered the tumorigenic potential of OS cells. The present study established a novel association between miR-336 and Sox-2 in OS. This relationship between miR-336 and Sox-2 may lead to improved knowledge concerning OS progression and sheds light on potential novel therapeutic interventions for OS treatment.