Taurine Upregulated Gene 1 Knockdown Research Articles

Long non-coding RNA TUG1 promotes colorectal cancer metastasis via EMT pathway.

Colorectal cancer (CRC) is the third most common malignancy in developed countries, and its incidence rate has been continuously increasing in developing countries over the past few decades. Taurine-upregulated gene 1 (TUG1) plays an important role in signal transduction, regulation of cell morphology, migration, proliferation and apoptosis. The aim of the present study was to evaluate the role of TUG1 in CRC, and whether knockdown of TUG1 expression could affect cell proliferation, migration and invasion of CRC cell lines. Here, we reported that TUG1 was upregulated in CRC. Further experiments revealed that TUG1 knockdown significantly inhibited cell proliferation, migration and invasion of CRC in vitro. Above all, knockdown of TUG1 may represent a rational therapeutic strategy for CRC patients in future.

The long non-coding RNA TUG1 indicates a poor prognosis for colorectal cancer and promotes metastasis by affecting epithelial-mesenchymal transition.

BackgroundLong intergenic non-coding RNAs (lncRNAs) are a class of non-coding RNAs that are involved in gene expression regulation. Taurine up-regulated gene 1 (TUG1) is a cancer progression related lncRNA in some tumor oncogenesis; however, its role in colorectal cancer (CRC) remains unclear. In this study, we determined the expression patterns of TUG1 in CRC patients and explored its effect on CRC cell metastasis using cultured representative CRC cell lines.MethodsThe expression levels of TUG1 in 120 CRC patients and CRC cells were determined using quantitative real-time PCR. HDACs and epithelial-mesenchymal transition (EMT)-related gene expression were determined using western blot. CRC cell metastasis was assessed by colony formation, migration assay and invasion assay.ResultsOur data showed that the levels of TUG1 were upregulated in both CRC cell lines and primary CRC clinical samples. TUG1 upregulation was closely correlated with the survival time of CRC patients. Overexpression of TUG1 in CRC cells increased their colony formation, migration, and invasion invitro and promoted their metastatic potential in vivo, whereas knockdown of TUG1 inhibited the colony formation, migration, and invasion of CRC cells invitro. It is also worth pointing out that TUG1 activated EMT-related gene expression.ConclusionOur data suggest that tumor expression of lncRNA TUG1 plays a critical role in CRC metastasis. TUG1 may have potential roles as a biomarker and/or a therapeutic target in colorectal cancer.

LncRNA Taurine-Upregulated Gene 1 Promotes Cell Proliferation by Inhibiting MicroRNA-9 in MCF-7 Cells.

PurposeThis study was designed to investigate the role of taurine-upregulated gene 1 (TUG1) in MCF-7 breast cancer cells and the molecular mechanism involved in the regulation of microRNA-9 (miR-9).MethodsThe expression of TUG1 in breast cancer tissues and cells was evaluated using quantitative reverse transcription polymerase chain reaction. Cell viability was examined using a 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay; cell cycle progression and apoptosis were analyzed using flow cytometry. A dual luciferase reporter assay was used to detect the relationship between TUG1 and miR-9. The expression of methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) was measured by western blot.ResultsHigher expression of TUG1 was observed in breast cancer tissues and cell lines than in the corresponding controls. TUG1 knockdown reduced proliferation, suppressed cell cycle progression, and promoted apoptosis of MCF-7 cells. The dual luciferase reporter assay showed that TUG1 could negatively regulate the expression of miR-9. MiR-9 inhibition abrogated the effect of TUG1 knockdown on the proliferation, cell cycle progression, and apoptosis of MCF-7 cells. TUG1 positively regulated the expression of MTHFD2 in breast cancer cells.ConclusionTUG1 knockdown was significantly associated with decreased cell proliferation and it promoted apoptosis of breast cancer cells through the regulation of miR-9.

The long noncoding RNA TUG1 regulates blood-tumor barrier permeability by targeting miR-144.

Blood-tumor barrier (BTB) limits the delivery of chemotherapeutic agent to brain tumor tissues. Long non-coding RNAs (lncRNAs) have been shown to play critical regulatory roles in various biologic processes of tumors. However, the role of lncRNAs in BTB permeability is unclear. LncRNA TUG1 (taurine upregulated gene 1) was highly expressed in glioma vascular endothelial cells from glioma tissues. It also upregulated in glioma co-cultured endothelial cells (GEC) from BTB model in vitro. Knockdown of TUG1 increased BTB permeability, and meanwhile down-regulated the expression of the tight junction proteins ZO-1, occludin, and claudin-5. Both bioinformatics and luciferase reporter assays demonstrated that TUG1 influenced BTB permeability via binding to miR-144. Furthermore, Knockdown of TUG1 also down-regulated Heat shock transcription factor 2 (HSF2), a transcription factor of the heat shock transcription factor family, which was defined as a direct and functional downstream target of miR-144. HSF2 up-regulated the promoter activities and interacted with the promoters of ZO-1, occludin, and claudin-5 in GECs. In conclusion, our results indicate that knockdown of TUG1 increased BTB permeability via binding to miR-144 and then reducing EC tight junction protein expression by targeting HSF2. Thus, TUG1 may represent a useful future therapeutic target for enhancing BTB permeability.

P53-regulated long non-coding RNA TUG1 affects cell proliferation in human non-small cell lung cancer, partly through epigenetically regulating HOXB7 expression.

Recently, a novel class of transcripts, long non-coding RNAs (lncRNAs), is being identified at a rapid pace. These RNAs have critical roles in diverse biological processes, including tumorigenesis. Here we report that taurine-upregulated gene 1 (TUG1), a 7.1-kb lncRNA, recruiting and binding to polycomb repressive complex 2 (PRC2), is generally downregulated in non-small cell lung carcinoma (NSCLC) tissues. In a cohort of 192 NSCLC patients, the lower expression of TUG1 was associated with a higher TNM stage and tumor size, as well as poorer overall survival (P<0.001). Univariate and multivariate analyses revealed that TUG1 expression serves as an independent predictor for overall survival (P<0.001). Further experiments revealed that TUG1 expression was induced by p53, and luciferase and chromatin immunoprecipitation (ChIP) assays confirmed that TUG1 was a direct transcriptional target of p53. TUG1 knockdown significantly promoted the proliferation in vitro and in vivo. Moreover, the lncRNA-mediated regulation of the expression of HOX genes in tumorigenesis and development has been recently receiving increased attention. Interestingly, inhibition of TUG1 could upregulate homeobox B7 (HOXB7) expression; ChIP assays demonstrated that the promoter of HOXB7 locus was bound by EZH2 (enhancer of zeste homolog 2), a key component of PRC2, and was H3K27 trimethylated. This TUG1-mediated growth regulation is in part due to specific modulation of HOXB7, thus participating in AKT and MAPK pathways. Together, these results suggest that p53-regulated TUG1 is a growth regulator, which acts in part through control of HOXB7. The p53/TUG1/PRC2/HOXB7 interaction might serve as targets for NSCLC diagnosis and therapy.

Down-regulation of long non-coding RNA TUG1 suppresses melanoma cell proliferation and induces apoptosis via up-regulating microRNA-9

With the development of next-generationsequencing technologies,longnon-coding RNAs (lncRNAs) have received increasing attention. Taurine Upregulated Gene 1 (TUG1) is anlncRNA that is required for differentiation of the murine retina. It remains unclear, however, whether TUG1 plays a functional role in human malignant melanoma. In this study, we demonstrated that levels of TUG1 were significantly increased in primary melanoma tissues as compared to benign nevi. Knockdown of TUG1 in melanoma cells induced up-regulation of microRNA-9 and down-regulation of its target genes. TUG1 inhibited microRNA-9 by base-pairing interaction. TUG1-siRNA treatment suppressed proliferation and induced apoptosis in melanoma cells. Anti-microRNA-9 expression vector reversed the phenotype changes caused by TUG11-siRNA. Our data suggest that the oncogenic role ofTUG1 in melanoma is related to suppression of microRNA-9. This study provides novel insights into the functional role of lncRNA in cancer biology.

The Noncoding RNA Taurine Upregulated Gene 1 Is Required for Differentiation of the Murine Retina

With the advent of genome-wide analyses, it is becoming evident that a large number of noncoding RNAs (ncRNAs) are expressed in vertebrates. However, of the thousands of ncRNAs identified, the functions of relatively few have been established. In a screen for genes upregulated by taurine in developing retinal cells, we identified a gene that appears to be a ncRNA. Taurine Upregulated Gene 1 (TUG1) is a spliced, polyadenylated RNA that does not encode any open reading frame greater than 82 amino acids in its full-length, 6.7 kilobase (kb) RNA sequence. Analyses of Northern blots and in situ hybridization revealed that TUG1 is expressed in the developing retina and brain, as well as in adult tissues. In the newborn retina, knockdown of TUG1 with RNA interference (RNAi) resulted in malformed or nonexistent outer segments of transfected photoreceptors. Immunofluorescent staining and microarray analyses suggested that this loss of proper photoreceptor differentiation is a result of the disregulation of photoreceptor gene expression. A function for a newly identified ncRNA, TUG1, has been established. TUG1 is necessary for the proper formation of photoreceptors in the developing rodent retina.