The Lncrna-TUG1/EZH2 Axis Promotes Pancreatic Cancer Cell Proliferation, Migration and EMT Phenotype Formation Through Sponging Mir-382

Background/Aims: Krüppel-like factor 4 (KLF4), a member of the KLF family of zinc finger transcription factors, has been identified as a tumor suppressor gene in a variety of tumors. However, the molecular mechanisms by which KLF4 inhibits epithelial-to-mesenchymal transition (EMT) and metastasis in pancreatic cancer remain unclear. Methods: KLF4 expression in pancreatic cancer was analyzed using public datasets (Oncomine and The Cancer Genome Atlas). The expression of KLF4, caveolin-1 (Cav-1), E-cadherin, and vimentin, and their correlations with clinicopathological characteristics were evaluated by immunohistochemistry in pancreatic cancer tissues. The biological functions and underlying mechanisms of KLF4 expression on EMT and metastasis were also investigated in vitro and in vivo. Results: Public datasets showed that KLF4 expression was significantly decreased in pancreatic cancer and correlated with the depth of invasion and disease stage. The expression of KLF4, Cav-1, E-cadherin, and vimentin protein in pancreatic cancer tissues was closely associated with pathological grade, disease stage, and metastasis. KLF4 expression was also positively correlated with E-cadherin expression and negatively correlated with vimentin expression, whereas Cav-1 expression was negatively associated with E-cadherin expression and positively correlated with vimentin expression. Knockdown of KLF4 expression promoted EMT and facilitated pancreatic cancer cell growth and metastasis in vitro and in vivo. In addition, immunohistochemistry (IHC) results indicated that KLF4 expression was negatively correlated with Cav-1 expression. Furthermore, down-regulating KLF4 expression increased Cav-1 and vimentin expression and decreased E-cadherin expression. Mechanistically, KLF4 could transcriptionally inhibit Cav-1 expression by binding directly to the promoter domain of Cav-1. Conclusions: KLF4 inhibits pancreatic cancer EMT and metastasis by down-regulating Cav-1 expression, suggesting that the KLF4/Cav-1 signaling pathway may be a novel diagnostic and therapeutic target.

Section: Discussionsupporting

confidence: 57%

Krüppel-Like Factor 4 Inhibits Pancreatic Cancer Epithelial-to-Mesenchymal Transition and Metastasis by Down-Regulating Caveolin-1 Expression

Zhu

Wang

et al. 2018

“…The lncRNA taurine upregulated gene 1 (TUG1) plays a role in the progression of several human cancers by interacting with miRNAs Wang et al [22][23][24]. For example, TUG1 accelerates the malignancy of pancreatic cancer through sponging miR-382 Zhao et al [25], mediates methotrexate resistance in colorectal cancer (CRC) by interacting with miR-186 Li et al [26], acts as an oncogene in osteosarcoma by binding with miR-335 Wang et al [22], and improves gastric cancer progression through sponging miR-145-5p Ren et al [24]. Thus, this study aimed to clarify the interaction between TUG1 and miR-142-3p in HCC.…”

Section: Introductionmentioning

confidence: 99%

lncRNA TUG1-Mediated Mir-142-3p Downregulation Contributes to Metastasis and the Epithelial-to-Mesenchymal Transition of Hepatocellular Carcinoma by Targeting ZEB1

Liu

Jin

et al. 2018

Background/Aims: MicroRNA-142-3p (miR-142-3p) is dysregulated in many malignancies and may function as a tumor suppressor or oncogene in tumorigenesis and tumor development. However, few studies have investigated the clinical significance and biological function of miR-142-3p in hepatocellular carcinoma (HCC). Methods: The expression levels of taurine upregulated gene 1 (TUG1), miR-142-3p, and zinc finger E-box-binding homeobox 1 (ZEB1) were evaluated in HCC tissues and cell lines by quantitative real-time PCR. MTT and colony formation assays were used to detect cell proliferation ability, transwell assays were used to assess cell migration and invasion, and luciferase reporter assays were used to examine the interaction between the long noncoding RNA TUG1 and miR-142-3p. Tumor formation was evaluated through in vivo experiments. Results: miR-142-3p was significantly downregulated in HCC tissues, but TUG1 was upregulated in HCC tissues. Knockdown of TUG1 and upregulation of miR-142-3p inhibited cell proliferation, cell migration, cell invasion, and the epithelial-mesenchymal transition (EMT). miR-142-3p was found to be a prognostic factor of HCC, and the mechanism by which TUG1 upregulated ZEB1 was via direct binding to miR-142-3p. In vivo assays showed that TUG1 knockdown suppressed cell proliferation and the EMT in nude mice. Conclusion: The results of this study suggest that the TUG1/miR-142-3p/ ZEB1 axis contributes to the formation of malignant behaviors in HCC.

“…We tentatively thought that a reciprocal regulatory mechanism might underlie p53 and TUG1, which demands further investigation. Furthermore, investigators have identified several targets of TUG1, such as the microRNAs MiR-197 [36], MiR-221 [37], MiR-222 [37] and MiR382 [38] and Krüppel-like factor [26], and that the interaction between TUG1 and these targets may can cause transcriptional changes in downstream genes, expression of which is crucial for processes such as tumorigenesis and metastasis. Therefore, we plan to further investigate the molecular mechanism of TUG1's involvement in the pathogenesis of LSCC, including its impact on the p53-dependent signaling pathway, to fully understand its function.…”

Section: Discussionmentioning

confidence: 99%

The Long Noncoding RNA TUG1 Promotes Laryngeal Cancer Proliferation and Migration

Zhang

Wang

Cao

et al. 2018

Background/Aims: Researchers have shown that long noncoding RNAs are closely associated with the pathogenesis of laryngeal squamous cell carcinoma (LSCC). However, the role of the long noncoding RNA taurine-upregulated gene 1 (TUG1) in the pathogenesis of LSCC remains unclear, although it is recognized as an oncogenic regulator for several types of squamous cell carcinoma. Methods: qRT-PCR was performed to measure the expression of TUG1 in LSCC tissues and cell lines. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) was used to measure the effect of TUG1 on cell proliferation. Transwell assay and flow cytometry were employed to determine the effect of TUG1 on cell migration and invasion. Western-blot were performed to explore the relation of TUG1 and p53 mRNA. Results: Higher TUG1 expression in LSCC than in paired normal tumor-adjacent tissue specimens (N = 64) was observed using quantitative real-time polymerase chain reaction. Also, high TUG1 expression was positively associated with advanced T category, worse lymph node metastasis and late clinical stage. Furthermore, in vitro experiments demonstrated that silencing of TUG1 markedly inhibited proliferation, cell-cycle progression, migration, and invasion of LSCC cells, whereas depletion of TUG1 led to increased apoptosis. Conclusion: These findings demonstrated that upregulated TUG1 expression exerted oncogenic effects by promoting proliferation, migration, and invasion, and inhibiting apoptosis in LSCC cells.