Long noncoding RNA UCA1 promotes osteosarcoma metastasis through CREB1-mediated epithelial-mesenchymal transition and activating PI3K/AKT/mTOR pathway

Increasing evidences have demonstrated that Long noncoding RNAs (lncRNAs) are key regulatory RNAs that participate in multiple biological processes. LncRNA urothelial carcinoma-associated 1 (UCA1) is a newly identified lncRNA and functions as a regulator of growth in several cancers. However, the biological function and molecular mechanism of UCA1 in the metastasis of osteosarcoma remain unclear. In this study, we firstly found UCA1 is upregulated in both osteosarcoma tissues and cell lines, and increased UCA1 is associated with higher tumor stage, larger tumor size and poorer prognosis. Then for the first time, we demonstrated that UCA1 promotes the invasion and metastasis of osteosarcoma both in vitro and in vivo. Further mechanistic investigation showed that UCA1 directly interactes with miR-582 and suppresses its expression. Moreover, UCA1 increases CREB1 expression by functioning as a ceRNA against miR-582, thus promoting the EMT process via CREB1-mediated PI3K/AKT/mTOR pathway and finally leading to osteosarcoma metastasis. These findings may extend the function of UCA1 in osteosarcoma progression and provide a promising therapeutic target for osteosarcoma treatment.