Long non-coding RNA Sox4 promotes proliferation and migration by activating Wnt/β-catenin signaling pathway in osteosarcoma.

Osteosarcoma is a bone tumor without effective treatment in the world. Recently, long non-coding RNAs (lncRNAs) are considered as essential regulators in cancer progression. LncSox4 plays crucial roles in liver tumor-initiating cells self-renewal and tumor initiation. However, the effect of lncSox4 in osteosarcoma remains largely unclear. Quantitative real-time PCR (qRT-PCR) and Northern blot were performed to detect lncSox4 expressions in osteosarcoma. The functions of lncSox4 in osteosarcoma were determined using cell viability and migration assays. In addition, the proteins associated with lncSox4 were further evaluated by western blot. We found that lncSox4 was expressed highly in U-20S and Mg63 cells and osteosarcoma tumor tissues (all P < 0.001). LncSox4 silencing attenuated but lncSox4 overexpression promoted cell viability (all P < 0.001) and migration (P < 0.01) in the Mg63 cells. Next, we found lncSox4 regulation of osteosarcoma is involved in β-catenin, and overexpression of lncSox4 could stable β-catenin expression. Further, Wnt agonist CID11210285 completely abolished the decrease of Mg63 cells viability induced by lncSox4 silencing when cells cultured for 3 and 4 days (both P < 0.01), while Wnt inhibitor IWP-3 abolished the increase of Mg63 cells viability induced by overexpression of lncSox4 after treatment for 2 (P < 0.01), 3 (P < 0.001) and 4 (P < 0.01) days. Our study offers evidence for the first time that lncSox4 plays a positive role in osteosarcoma development and progression, and could act as a potential prognostic and therapy biomarker.