Abstract
BACKGROUND: Bladder cancer (BC) is a common type of cancer that involves tumors of the urinary system and poses a serious threat to human health. Long noncoding RNAs (lncRNAs) have emerged as crucial biomarkers and regulators in many cancers. Novel lncRNA biomarkers in BC urgently need to be investigated in regard to its function and regulatory mechanisms. METHODS: Identification of differentially expressed lncRNAs in BC tissue was performed via microarray analysis. To investigate the biological functions of LINC00612, loss-of-function and gain-of-function experiments were performed in vitro and in vivo. Bioinformatics analysis, dual-luciferase reporter assays, AGO2-RIP assays, RNA pull-down assays, real-time quantitative PCR (RT-qPCR) arrays, fluorescence in situ hybridization assays, and western blot assays were conducted to explore the underlying mechanisms of competitive endogenous RNAs (ceRNAs). RESULTS: LINC00612 was upregulated in BC tissues and cell lines. Functionally, downregulation of LINC00612 inhibited cell proliferation and invasion in vitro and in vivo, whereas overexpression of LINC00612 resulted in the opposite effects. Bioinformatics analysis and luciferase assays revealed that miR-590 was a direct target of LINC0061, which was validated by dual-luciferase reporter assays, AGO2-RIP assays, RNA pull-down assays, RT-qPCR arrays, and rescue experiments. Additionally, miR-590 was shown to directly target the PHD finger protein 14 (PHF14) gene. LNIC00612 modulated the expression of E-cadherin and vimentin by competitively sponging miR-590 to elevate the expression of PHF14, thus affecting BC cellular epithelial-mesenchymal transition (EMT). CONCLUSIONS: Our results indicate that LINC00612 enhances the proliferation and invasion ability of BC cells by sponging miR-590 to upregulate PHF14 expression and promote BC cellular EMT, suggesting that LINC00612 may act as a potential biomarker and therapeutic target for BC.