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Background/Aims: Pancreatic carcinoma (PC) is the one of the most common and malignant cancers worldwide. LncRNA taurine upregulated gene 1 (TUG1) was initially identified as a transcript upregulated by taurine, and the abnormal expression of TUG1 has been reported in many cancers. However, the biological role and molecular mechanism of TUG1 in PC still needs further investigation. Methods: Quantitative real-time PCR (qRT-PCR) was performed to measure the expression of TUG1 in PC cell lines and tissues. MTT and colony formation assays were used to measure the effect of TUG1 on cell proliferation. A wound healing assay, transwell assay and western blot assay were employed to determine the effect of TUG1 on cell migration and the epithelial mesenchymal transition (EMT) phenotype. RNA-binding protein immunoprecipitation (RIP) and a biotin-avidin pulldown system were performed to confirm the interaction between miR-328 and TUG1. A gene expression array analysis using clinical samples and RT-qPCR suggested that enhancer of zeste homolog 2 (EZH2) was a target of miR-382 in PC. Results: In this study, we reported that TUG1 was overexpressed in PC tissues and cell lines, and high expression of TUG1 predicted poor prognosis. Further experiments revealed that overexpressed TUG1 promoted cell proliferation, migration and contributed to EMT formation, whereas silenced TUG1 led to opposing results. Additionally, luciferase reporter assays, an RIP assay and an RNA-pulldown assay demonstrated that TUG1 could competitively sponge miR-382 and thereby regulate EZH2. Conclusion: Collectively, these findings revealed that TUG1 functions as an oncogenic lncRNA that promotes tumor progression, at least partially, by functioning as an endogenous 'sponge' and competing for miR-382 binding to the miRNA target EZH2. [ABSTRACT FROM AUTHOR]

Abstract It is commonly recognized that aberrant expression of long non-coding RNAs (lncRNAs) is an important cause of cancer progression. The oncogenic property of KCNQ1OT1 has been identified in several malignant tumors. Here, we decided to explore the biological function and molecular mechanism of KCNQ1OT1 in cholangiocarcinoma (CCA). The expression conditions of KCNQ1OT1 in different tissues and cell lines were examined with qRT-PCR analysis. As expected, KCNQ1OT1 was highly expressed in CCA tissues and cell lines. Results of functional assays revealed the oncogenic function of KCNQ1OT in cholangiocarcinoma progression. The positive effect of KCNQ1OT1 on cell proliferation, invasion and epithelial-mesenchymal transition was identified by performing MTT assay, colony formation assay, transwell invasion assay and western blotting. Whereas, the negative effect of KCNQ1OT1 on the cell apoptosis was tested with flow cytometry analysis. Mechanism investigation revealed that KCNQ1OT1 can act as a ceRNA to improve CCA progression by regulating miR-140-5p/SOX4 axis. Recue assays were conducted to demonstrate the actual effects of KCNQ1OT1-miR-140-5p-SOX4 pathway on CCA progression. Highlights • Overexpressed KCNQ1OT1 is a prognostic factor for CCA patients. • The inhibitory effects of silenced KCNQ1OT1 on proliferation, EMT progress and invasion of CCA cells. • KCNQ1OT1 upregulates SOX4 through competitively binding with miR-140-5p. • KCNQ1OT1 improves CCA progression in a miR-140-5p/SOX4 dependent manner. [ABSTRACT FROM AUTHOR]