Long non-coding RNA TUG1 promotes cell proliferation and metastasis in human breast cancer

Roles of lncRNAs related to the p53 network in breast cancer progression

The p53 is a crucial tumor suppressor and transcription factor that participates in apoptosis and senescence. It can be activated upon DNA damage to regulate the expression of a series of genes. Previous studies have demonstrated that some specific lncRNAs are part of the TP53 regulatory network. To enhance our understanding of the relationship between lncRNAs and P53 in cancers, we review the localization, structure, and function of some lncRNAs that are related to the mechanisms of the p53 pathway or serve as p53 transcriptional targets.

AMPFLDAP: Adaptive Message Passing and Feature Fusion on Heterogeneous Network for LncRNA-Disease Associations Prediction

Exploration of the intricate connections between long noncoding RNA (lncRNA) and diseases, referred to as lncRNA-disease associations (LDAs), plays a pivotal and indispensable role in unraveling the underlying molecular mechanisms of diseases and devising practical treatment approaches. It is imperative to employ computational methods for predicting lncRNA-disease associations to circumvent the need for superfluous experimental endeavors. Graph-based learning models have gained substantial popularity in predicting these associations, primarily because of their capacity to leverage node attributes and relationships within the network. Nevertheless, there remains much room for enhancing the performance of these techniques by incorporating and harmonizing the node attributes more effectively. In this context, we introduce a novel model, i.e., Adaptive Message Passing and Feature Fusion (AMPFLDAP), for forecasting lncRNA-disease associations within a heterogeneous network. Firstly, we constructed a heterogeneous network involving lncRNA, microRNA (miRNA), and diseases based on established associations and employing Gaussian interaction profile kernel similarity as a measure. Then, an adaptive topological message passing mechanism is suggested to address the information aggregation for heterogeneous networks. The topological features of nodes in the heterogeneous network were extracted based on the adaptive topological message passing mechanism. Moreover, an attention mechanism is applied to integrate both topological and semantic information to achieve the multimodal features of biomolecules, which are further used to predict potential LDAs. The experimental results demonstrated that the performance of the proposed AMPFLDAP is superior to seven state-of-the-art methods. Furthermore, to validate its efficacy in practical scenarios, we conducted detailed case studies involving three distinct diseases, which conclusively demonstrated AMPFLDAP's effectiveness in the prediction of LDAs.

Role of long non-coding RNAs in cholangiocarcinoma: A systematic review and meta-analysis

BACKGROUND

Cholangiocarcinoma (CCA), as a rare malignancy of the biliary tree, has a poor prognosis most of the time. CCA is highly epigenetically regulated and several long non-coding RNAs (lncRNA) have been investigated to have a diagnostic and prognostic role in CCA. The current study aimed to assess the studies finding relevant lncRNAs in CCA systematically.

METHODS

International databases, including PubMed, Cochrane Library, and Embase, were comprehensively searched in order to identify studies investigating any lncRNA in CCA. After screening by title/abstract and full-text, necessary data were extracted. Random-effect meta-analysis was performed for pooling the areas under the curve (AUCs), specificity, and sensitivity of lncRNAs for the diagnosis of CCA.

RESULTS

A total of 33 studies were chosen to be included in the final analysis, comprised of 2677 patients. Meta-analysis of AUCs for evaluation of CCA resulted in pooled AUC of 0.79 (95% CI: 0.75-0.82; I2 = 69.11, p < .01). Additionally, overall sensitivity of 0.80 (95% CI 0.75-0.84) and specificity of 0.77 (95% CI: 0.68-0.84) were observed. Measurement of lncRANs in the assessment of CCA also improved overall survival significantly (effect size 1.61, 95% CI: 1.39-1.82). A similar result was found for progression-free survival (effect size 1.57, 95% CI: 1.20-1.93).

CONCLUSION

Based on our findings, lncRNAs showed promising results as biomarkers in the diagnosis of CCA since they had acceptable sensitivity and specificity, in addition to the fact that improved survival in this poor prognosis cancer. Further studies might be needed to address this issue and find the best clinically useful lncRNA.

The role of mitochondrial/metabolic axis in development of tamoxifen resistance in breast cancer

Only a few investigations, to our knowledge, have examined the bioenergetics of Tamoxifen (TMX) resistant individuals and reported altered mitochondrial activity and metabolic profile. The primary cause of TMX resistance is firmly suggested to be metabolic changes. Metabolic variations and hypoxia have also been linked in a bidirectional manner. Increased hypoxic levels correlate with early recurrence and proliferation and have a negative therapeutic impact on breast cancer (BC) patients. Hypoxia, carcinogenesis, and patient death are all correlated, resulting in more aggressive traits, a higher chance of metastasis, and TMX resistance. Consequently, we sought to investigate the possible role of the metabolic/hypoxial axis Long non-coding RNA (LncRNA) Taurine up-regulated 1 (TUG-1), Micro-RNA 186-5p (miR-186), Sirtuin-3 (SIRT3), Peroxisome Proliferator Activator Receptor alpha (PPAR-α), and Hypoxia-Inducible Factor-1 (HIF-1) in the development of TMX resistance in BC patients and to correlate this axis with tumor progression. Interestingly, this will be the first time to explore epigenetic regulation of this axis in BC.

Metformin and long non-coding RNAs in breast cancer

Breast cancer (BC) is the second most common cancer and cause of death in women. In recent years many studies investigated the association of long non-coding RNAs (lncRNAs), as novel genetic factors, on BC risk, survival, clinical and pathological features. Recent studies also investigated the roles of metformin treatment as the firstline treatment for type 2 diabetes (T2D) played in lncRNAs expression/regulation or BC incidence, outcome, mortality and survival, separately. This comprehensive study aimed to review lncRNAs associated with BC features and identify metformin-regulated lncRNAs and their mechanisms of action on BC or other types of cancers. Finally, metformin affects BC by regulating five BC-associated lncRNAs including GAS5, HOTAIR, MALAT1, and H19, by several molecular mechanisms have been described in this review. In addition, metformin action on other types of cancers by regulating ten lncRNAs including AC006160.1, Loc100506691, lncRNA-AF085935, SNHG7, HULC, UCA1, H19, MALAT1, AFAP1-AS1, AC026904.1 is described.

Serum-Based lncRNA ANRIL, TUG1, UCA1, and HIT Expressions in Breast Cancer Patients

Breast cancer is a heterogeneous disease and is the most common and prevalent form of malignancy diagnosed in women. lncRNAs are found to be frequently dysregulated in cancer, and its expression plays a critical role in tumorigenesis. The study included 100 histopathologically confirmed, newly diagnosed untreated patients of invasive ductal carcinoma (IDC) of breast cancer patients and 100 healthy subjects. After blood collection, the serum was separated and total RNA was extracted, cDNA was synthesized using 100 ng of total RNA, and lncRNA (ANRIL, TUG1, UCA1, and HIT) expression was analyzed. Increased ANRIL (3.83-fold), TUG1 (7.64-fold), UCA1 (7.82-fold), and HIT (3.31-fold) expressions were observed in breast cancer patients compared to healthy controls. Relative expression of lncRNAs UCA-1 (p = 0.010) and HIT-1 (p < 0.0001) was significantly elevated in patients with advanced breast cancer stage compared to those with early-stage disease. While lncRNA TUG-1 expression was found to be higher in patients with early-stage tumors than those with advanced-stage tumors (p = 0.06), lncRNA ANRIL showed increased expression in patients with PR positive status (p = 0.04). However, we found a significant difference in lncRNA HIT expression in HER-2 positive breast cancer patients compared to HER-2 negative breast cancer patients (p = 0.005). An increase in the expression of serum lncRNAs ANRIL (p < 0.0001), UCA-1 (p = 0.004), and HIT (p < 0.0001) was observed in the distant organ metastatic breast cancer patients. In the ROC curve concerning lymph node involvement, the sensitivity and specificity of lncRNA HIT were 68% and 58%, respectively (p value = 0.007). In the ROC curve w.r.t. stages of disease, the sensitivity and specificity of lncRNA HIT were 80% and 50%, respectively (p value < 0.0001). Better sensitivity and specificity were observed for lncRNA HIT (sensitivity 91% and specificity 78%; p value < 0.0001) and ANRIL (sensitivity 70% and specificity 60%; p value < 0.0001) w.r.t distant organ metastases.

Long non-coding RNA TUG1 promotes proliferation and migration in PDGF-BB-stimulated HASMCs by regulating miR-216a-3p/SMURF2 axis

BACKGROUND

Abnormal proliferation and migration of human airway smooth muscle cells (HASMCs) play an important role in the development of childhood asthma. Long non-coding RNAs (lncRNAs) have been demonstrated to participate in HASMC proliferation and migration. We aimed to explore more effects and molecular mechanism of taurine upregulated gene 1 (TUG1) in childhood asthma.

RESULTS

TUG1 and SMURF2 were overexpressed and miR-216a-3p was downregulated in childhood asthma patients and PDGF-BB-stimulated HASMCs. TUG1 knockdown attenuated PDGF-BB-triggered proliferation and migration of HASMCs. MiR-216a-3p was targeted by TUG1, and miR-216a-3p suppression counteracted the repressive effects of TUG1 interference on proliferation and migration in PDGF-BB-treated HASMCs. SMURF2 was a downstream target of miR-216a-3p, and SMURF2 upregulation abated the inhibiting effects of miR-216a-3p on migration and proliferation in PDGF-BB-exposed HASMCs. TUG1 sponged miR-216a-3p to positively regulate SMURF2 expression.

CONCLUSION

TUG1 downregulation inhibited PDGF-BB-induced HASMC proliferation and migration by regulating miR-216a-3p/SMURF2 axis, offering novel insight into the potential application of TUG1 for childhood asthma treatment.

LncRNA-TUG1 promotes the progression of infantile hemangioma by regulating miR-137/IGFBP5 axis

Background

Previous studies indicated that lncRNA taurine upregulated gene 1 (TUG1) played essential roles in human cancers. This study aimed to investigate its function in infantile hemangioma (IH).

Methods

A total of 30 pairs of clinical infantile specimens were used in this study. The expression of TUG1 in IH tissues was assessed by quantitative reverse transcriptase PCR (qRT-PCR). Two short hairpin RNA targeting TUG1 (sh-TUG1-1 and sh-TUG1-2) were transfected into hemangioma-derived endothelial cells, HemECs, to block its expression. The effects of TUG1 on HemECs were evaluated by Cell Counting Kit-8 (CCK-8), colony formation assay, wound healing assay, and Transwell assay. The underlying molecular mechanism of TUG1 was investigated by Starbase prediction and luciferase reporter assay and further determined by loss- and gain-of-function approaches. In addition, the role of TUG1 on tumorigenesis of HemECs was confirmed in an in vivo mouse model.

Results

TUG1 was significantly upregulated in infant hemangioma tissues compared with normal adjacent subcutaneous tissues. The loss- and gain-of-function approaches indicated that TUG1 overexpression promoted proliferation, migration, and invasion of HemECs in vitro, and TUG1 knockdown inhibited the tumorigenesis of HemECs in vivo. Specifically, TUG1 could compete with IGFBP5 for miR137 binding. Rescue experiments further confirmed the role of the TUG1/miR137/IGFBP5 axis in HemECs.

Conclusion

TUG1 was closely associated with the progression of IH by regulating the miR-137/IGFBP5 axis, which might be a potential target for IH treatment.

Association between long noncoding RNA taurine-upregulated gene 1 and microRNA-377 in vitiligo

BACKGROUND

Taurine-upregulated gene 1 (TUG1) is one of the long noncoding RNAs (lncRNAs) that plays a role in melanogenesis. MicroRNA-377 (miRNA-377) is a conserved noncoding RNA that regulates angiogenesis and promotes oxidative stress. Peroxisome proliferator-activated receptors (PPARs) are components of the nuclear hormone receptor superfamily. PPAR-γ activators stimulate melanogenesis. Interleukin (IL)-17 has been implicated in the pathogenesis of several immunological diseases. This work aimed at detecting the expression levels of lncRNA TUG1, miRNA-377, PPAR-γ, and IL-17 among vitiligo subjects and to investigate their possible role in the pathogenesis of vitiligo.

METHODS

This study was conducted on 30 healthy controls and 30 vitiligo patients. LncRNA TUG1 and miRNA-377 were detected in serum by real-time polymerase chain reaction (PCR). Also, expressions of PPAR-γ and IL-17 were assessed in tissue by real-time PCR.

RESULTS

LncRNA TUG1 and PPAR-γ levels were significantly downregulated in the vitiligo group compared with the control group. On the other hand, miRNA-377 and IL-17 were significantly upregulated in the vitiligo group compared with the control group.

CONCLUSION

This study demonstrated the dysregulated expressions of lncRNA TUG1 and miRNA-377 in patients with vitiligo suggesting that both contributed to the pathogenesis of vitiligo that might be through PPAR-γ downregulation and IL-17 upregulation.

TUG1 knockdown inhibits the tumorigenesis and progression of prostate cancer by regulating microRNA-496/Wnt/β-catenin pathway

Our study aimed to further investigate the roles and molecular mechanisms of lncRNA taurine upregulated gene 1 (TUG1) in the development and progression of PC. RT-qPCR assay was carried out to measure expression of TUG1, miR-496, together with β-catenin, cyclin D1 and c-myc. Protein levels of β-catenin, cyclin D1 and c-myc were detected by western blot assay. Cell proliferative ability was assessed by colony formation assay and CCK-8 assay. Cell migratory and invasive capacities were evaluated by Transwell migration and invasion assay. The interaction between miR-496 and TUG1 was explored by bioinformatics analysis, luciferase reporter assay and RNA immunoprecipitation assay. Mouse xenograft experiments were performed to further investigate the roles and molecular basis of TUG1 in the tumorigenesis of PC in vivo. TUG1 was highly expressed in PC tissues and cells (DU145 and PC3). TUG1 knockdown inhibited proliferation, migration and invasion in DU145 and PC3 cells. Moreover, TUG1 suppressed miR-496 expression by direct interaction. TUG1 overexpression abrogated miR-96-mediated antiproliferation, anti-migration and anti-invasion effects in DU145 and PC3 cells. TUG1 knockdown inactivated Wnt/β-catenin signaling pathway by upregulating miR-496 in DU145 and PC3 cells. Additionally, TUG1 knockdown inhibited DU145 cells derived PC xenograft growth by upregulating miR-496 and inactivating Wnt/β-catenin signaling in vivo. TUG1 knockdown suppressed PC cell proliferation, migration and invasion in vitro and curbed PC xenograft growth in vivo by regulating miR-496/Wnt/ β-catenin signaling pathway, deepening our understanding on etiology of PC.

Pathophysiological Functions of the lncRNA TUG1

BACKGROUND

Long non-coding RNAs (lncRNAs) with little or no coding capacity are associated with a plethora of cellular functions, participating in various biological processes. Cumulative study of lncRNA provides explanations to the physiological and pathological processes and new perspectives to the diagnosis, prevention, and treatment of some clinical diseases. Long non-coding RNA taurine-upregulated gene 1(TUG1) is one of the first identified lncRNAs associated with human disease, which actively involved in various physiological processes, including regulating genes at epigenetics, transcription, post-transcription, translation, and posttranslation. The aim of this review was to explore the molecular mechanism of TUG1 in various types of human diseases.

METHODS

In this review, we summarized and analyzed the latest findings related to the physiologic and pathophysiological processes of TUG1 in human diseases. The related studies were retrieved and selected the last six years of research articles in PubMed with lncRNA and TUG1 as keywords.

RESULTS

TUG1 is a valuable lncRNA that its dysregulated expression and regulating the biological processes were found in a variety of human diseases. TUG1 is found to exhibit aberrant expression in a variety of malignancies. Dysregulation of TUG1 has been shown to contribute to proliferation, migration, cell cycle changes, inhibited apoptosis, and drug resistance of cancer cells, which revealed an oncogenic role for this lncRNA, but some reports have shown downregulation of TUG1 in lung cancer samples compared with noncancerous samples. In addition, the molecular and biological functions of TUG1 in physiology and disease (relevant to endocrinology, metabolism, immunology, neurobiology) have also been highlighted. Finally, we discuss the limitations and tremendous diagnostic/therapeutic potential of TUG1 in cancer and other diseases.

CONCLUSION

Long non-coding RNA-TUG1 likely served as useful disease biomarkers or therapy targets and effectively applied in different kinds of diseases, such as human cancer and cardiovascular diseases.

The roles of long noncoding RNAs in breast cancer metastasis

Breast cancer is the most significant threat to female health. Breast cancer metastasis is the major cause of mortality in breast cancer patients. To fully unravel the molecular mechanisms that underlie the breast cancer cell metastasis is critical for developing strategies to improve survival and prognosis in breast cancer patients. Recent studies have revealed that the long noncoding RNAs (lncRNAs) are involved in breast cancer metastasis through a variety of molecule mechanisms, though the precise functional details of these lncRNAs are yet to be clarified. In the present review, we focus on the functions of lncRNAs in breast cancer invasion and metastasis, with particular emphasis on the functional properties, the regulatory factors, the therapeutic promise, as well as the future challenges in studying these lncRNA.

Emodin relieved lipopolysaccharide-evoked inflammatory damage in WI-38 cells by up-regulating taurine up-regulated gene 1

BACKGROUND

Neonatal pneumonia (NP) has a high fatality rate in neonatal illness. This research investigated the functions of emodin on lipopolysaccharide (LPS)-evoked inflammatory injury in WI-38 cells.

METHODS

Cell counting kit-8 (CCK-8) assay and flow cytometry were utilized for examining the impacts of LPS and emodin on viability and apoptosis, respectively. Taurine up-regulated gene 1 (TUG1) level was altered through cell transfection and investigated by reverse transcription quantitative polymerase chain reaction (RT-qPCR). Moreover, RT-qPCR, western blot and enzyme-linked immunosorbent assay (ELISA) were utilized for investigating expressions of monocyte chemoattractant protein-1 (MCP-1) and interleukin (IL)-6. Western blot was carried out for investigating the levels of Bcl-2, Bax, pro-Caspase-3, cleaved-Caspase-3 and NF-κB and p38MAPK pathway-related proteins.

RESULTS

LPS treatment restrained cell viability, enhanced apoptosis, and expressions of inflammation-related IL-6 and MCP-1. Emodin alleviated LPS-evoked inflammatory injury and restrained the NF-κB and p38MAPK pathways. Furthermore, emodin positively regulated TUG1 expression and TUG1 silencing could reverse the efficacy of emodin on IL-6 and MCP-1 expressions. Finally, TUG1 regulates the expression of inflammatory factors through NF-κB and p38MAPK pathways.

CONCLUSION

Emodin alleviated LPS-evoked inflammatory injury by raising TUG1 expression via NF-κB and p38MAPK pathways in WI-38 cells.

Long non-coding RNA regulation of TRAIL in breast cancer: A tangle of non-coding threads

Breast cancer is a complex disease posing a serious threat to the female population worldwide. A complex molecular landscape and tumor heterogeneity render breast cancer cells resistant to drugs and able to promote metastasis and invasiveness. Despite the recent advancements in diagnostics and drug discovery, finding an effective cure for breast cancer is still a major challenge. Positive and negative regulation of apoptosis has been a subject of extensive study over the years. Numerous studies have shed light on the mechanisms that impede the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) signaling cascade. Long non-coding RNAs (lncRNAs) have been implicated in the orchestration, development, proliferation, differentiation and metastasis of breast cancer. However, the roles of lncRNAs in fine-tuning apoptosis regulating machinery in breast cancer remain to be elucidated. The present review illuminates the roles of these molecules in the regulation of breast cancer and the interplay between lncRNA and TRAIL in breast cancer. The present review also attempts to reveal their role in the regulation of apoptosis in breast cancer appears a promising approach for the development of new diagnostic and therapeutic regimens.

Long noncoding RNA TUG1 regulates prostate cancer cell proliferation, invasion and migration via the Nrf2 signaling axis

BACKGROUND

Long noncoding RNAs (lncRNAs) have been identified to modulate the development and progression of prostate cancer (PCa) via the regulation of their target genes. However, the biological function underlying the effect of lncRNA TUG1 in PCa remains unclear.

METHODS

Reverse transcription-quantitative polymerase chain reaction (qRT-PCR) and Western blotting analysis were used to assess the mRNA expression of TUG1 and protein expression levels of Nrf2 pathway members, respectively. The migration, invasion, and proliferation abilities of cells were assessed by the wound-healing, Transwell migration/invasion, and CCK8 assays, respectively.

RESULTS

TUG1 was strikingly upregulated in PCa cells compared with non-tumorigenic human prostate epithelial cells. The LncTar Web Server, which is a bioinformatics tool, was used to predict the target association between TUG1 and Nrf2. Moreover, the expression of TUG1 showed a strikingly positive correlation with that of Nrf2 in TCGA PCa RNA-Seq data (r = 0.26,P = 4.63E-09). Subsequently, inhibition of TUG1 using siRNA resulted in deceased proliferation, migration, and invasion of PCa cells; however, these effects were reversed by treatment with oltipraz (an activator of Nrf2). Finally, we evaluated the Nrf2 pathway to reveal the underlying mechanism of TUG1 in PCa cells, and found that TUG1 knockdown decreased the protein expression of Nrf2 downstream members (e.g., HO-1, FTH1, and NQO1).

CONCLUSIONS

LncRNA TUG1 plays an oncogenic role in human PCa cells by promoting the cell proliferation and invasion in PCa cell lines, at least partly via the Nrf2 signaling pathway.

Critical roles of long noncoding RNAs in breast cancer

Breast cancer is a major clinical challenge that affects a wide range of the female population and heavily burdens the health system. In the past few decades, attempts have been made to understand the etiology of breast cancer, possible environmental risk factors, and the genetic predispositions, pathogenesis, and molecular aberrations involved in the process. Studies have shown that breast cancer is a heterogeneous entity; each subtype has its specific set of aberrations in different cell signaling pathways, such as Notch, Wnt/β-catenin, transforming growth factor-β, and mitogen-activated protein kinase pathways. One novel group of molecules that have been shown to be inducted in the regulation of multiple cell signaling pathways is the long noncoding RNAs (lncRNAs). These molecules have important implications in the regulation of multiple signaling pathways by interacting with various genes, affecting the transcription process, and finally, playing roles in posttranslational control of these genes. There is growing evidence that lncRNAs are involved in the process of breast cancer formation by effecting the aforementioned signaling pathways, and that this involvement can have significant diagnostic and prognostic values in clinical contexts. The present review aims to elicit the significance of lncRNAs in the regulation of cell signaling pathways, and the resulting changes in cell survival, proliferation, and invasion, which are the hallmarks of breast cancer.

Long Non-Coding RNA and Breast Cancer

Breast cancer, one of the most common diseases among women, is regarded as a heterogeneous and complicated disease that remains a major public health concern. Recently, owing to the development of next-generation sequencing technologies, long non-coding RNAs have received extensive attention. Numerous studies reveal that long non-coding RNAs are playing important roles in tumor development. Although the biological function and molecular mechanisms of long non-coding RNAs remain enigmatic, recent researchers have demonstrated that an array of long non-coding RNAs express abnormally in cancers, including breast cancer. Herein, we summarized the latest literature about long non-coding RNAs in breast cancer, with a particular focus on the multiple molecular roles of regulatory long non-coding RNAs that regulate cell proliferation, invasion, metastasis, and apoptosis.

Long non-coding RNA TUG1 promotes cell progression in hepatocellular carcinoma via regulating miR-216b-5p/DLX2 axis

BACKGROUND

Accumulating evidence indicates that the long noncoding RNA taurine upregulated gene 1(TUG1) plays a critical role in cancer progression and metastasis. However, the overall biological role and clinical significance of TUG1 in hepatocellular carcinoma (HCC) remain largely unknown.

METHODS

The expressions of TUG1, microRNA-216b-5p and distal-less homeobox 2 (DLX2) were detected by Quantitative real-time polymerase chain reaction (qRT-PCR). The target relationships were predicted by StarBase v.2.0 or TargetScan and confirmed by dual-luciferase reporter assay. The cell growth, apoptosis, migration and invasion were detected by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), Flow cytometry and Transwell assays, respectively. All protein expression levels were detected by western blot. Tumor xenografts were implemented to explore the role of TUG1 in vivo.

RESULTS

We found that there was a marked rise in TUG1 expression in HCC tissues and cells, and knockdown of TUG1 repressed the growth and metastasis and promoted apoptosis of HCC cells. In particular, TUG1 could act as a ceRNA, effectively becoming a sink for miR-216b-5p to fortify the expression of DLX2. Additionally, repression of TUG1 impared the progression of HCC cells by inhibiting DLX2 expression via sponging miR-216b-5p in vitro. More importantly, TUG1 knockdown inhibited HCC tumor growth in vivo through upregulating miR-216b-5p via inactivation of the DLX2.

CONCLUSION

TUG1 interacting with miR-216b-5p contributed to proliferation, metastasis, tumorigenesis and retarded apoptosis by activation of DLX2 in HCC.

Long non-coding RNAs in non-small cell lung cancer: functions and distinctions from other malignancies

Lung cancer leads to the most cancer-related death in the world. It was shown from the increasing evidences that long non-coding RNAs (lncRNAs) are emerging as molecules for diagnosis, prognosis and even therapy of lung cancer and other malignancies. The biological functions or involved signaling pathways of lncRNAs are always found to be inconsistent among different types of malignancies. However, no available literature has systemically summarized differences in the functions and underlying molecular mechanisms of lncRNAs between lung cancer and other cancers. In this review, the biological functions and molecular mechanisms of lncRNAs in lung cancer were introduced. Furthermore, their functional differences between lung cancer and other malignancies were discussed. Finally, their potential clinical applications in future lung cancer therapy were focused on.

Molecular mechanisms of TUG1 in the proliferation, apoptosis, migration and invasion of cancer cells

Long non-coding RNAs (lncRNAs) are RNA sequences >200 nucleotides in length that have no protein-coding capacity. lncRNAs serve key roles in multiple biological processes, such as tumorigenesis and tumor progression. Taurine upregulated 1 (TUG1) is a novel lncRNA that has been associated with human cancer. TUG1 has attracted increasing attention in recent years and has been documented to be abnormally expressed in different types of cancer. Numerous studies indicate that TUG1 may be significantly associated with tumor development and cell metabolism by regulating cell proliferation, invasion, metastasis, apoptosis, differentiation and drug resistance. TUG1 exerts its function via recruiting specific RNA-binding proteins, promoting target gene expression, influencing tumor angiogenesis and by functioning as a competing endogenous RNA (ceRNA). An increasing number of studies have demonstrated that ceRNAs serve a role in cancer development. TUG1 is considered to be a biomarker or a novel therapeutic target for the diagnosis and prognosis of different cancer types. The present review focuses on recent developments in the major underlying molecular mechanisms of TUG1 in cancer, including its role in cell proliferation, apoptosis, migration, invasion and drug resistance. Also discussed in the present review is the current knowledge regarding the regulation of TUG1.

Long non-coding RNA small nucleolar RNA host gene 7 is upregulated and promotes cell proliferation in thyroid cancer

Thyroid cancer (THCA) is one of the most common types of endocrine cancer worldwide. However, the mechanisms underlying THCA progression have not been fully elucidated. Recent studies have demonstrated that long non-coding RNAs (lncRNAs) are dysregulated in human diseases, and are involved in regulating various biological processes. Furthermore, several reports have indicated that lncRNAs serve important roles in THCA. In the present study, a dataset from The Cancer Genome Atlas was used to analyze the expression levels and the clinical information of small nucleolar RNA host gene 7 (SNHG7) in THCA. Starbase was used to construct the competing endogenous RNA network. The Molecule Annotation System was used to analyze the data from Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases. Furthermore, cell proliferation and cell cycle assays were used to detect the functions of SNHG7 in THCA. The present study revealed for the first time, to the best of our knowledge, that SNHG7 is markedly upregulated in THCA samples following analysis of The Cancer Genome Atlas datasets. SNHG7 expression was higher in advanced stage compared with early stage THCA samples. In addition, high expression levels of SNHG7 were associated with shorter survival times in THCA patients compared with low expression levels. Bioinformatics analysis revealed that SNHG7 was associated with the processes of ‘protein translation’, ‘viral life cycle’, ‘RNA processing’, ‘mRNA splicing’, ‘histone ubiquitination’, ‘endoplasmic reticulum-to-Golgi vesicle-mediated transport’, ‘sister chromatid cohesion’, ‘DNA damage checkpoint regulation’, ‘translation’ and ‘the spliceosome’. Additionally, knockdown of SNHG7 significantly inhibited thyroid cancer cell proliferation and cell cycle progression in vitro. Taken together, the results obtained in the present study suggested that SNHG7 may serve as a novel therapeutic and prognostic target for THCA.

The lncRNA TUG1/miR-145-5p/FGF10 regulates proliferation and migration in VSMCs of hypertension

Vascular remodeling is a characteristic pathological feature of hypertension, it can cause of increasing vascular resistance and decrease of compliance. Vascular smooth muscle cell (VSMCs) dysfunction is the important foundation of vascular remodeling. Increasing evidences have revealed that lncRNA is an important regulatory factor of VSMC function. In this paper, we explored the function of lncRNA TUG1 in vascular remodeling of hypertension. Here, we found that lncRNA TUG1 was highly expressed in aorta of spontaneously hypertensive rats (SHR) rats and promoted the proliferation and migration of VSMCs (SHR-VSMCs). Bioinformatics analyze showed that lncRNA TUG1 sequence had miR-145-5p binding sites. Luciferase reporter test, RNA pulldown and qRT-PCR showed that lncRNA TUG1 could bind miR-145-5p. Similarly, bioinformatics analyze found that FGF10 3 'UTR contained miR-145-5p binding sites. Luciferase reporter test, qRT-PCR and Western blot were shown that miR-145-5p inhibited FGF10 expression by binding to its 3 'UTR. MTT showed that miR-145-5p inhibited and FGF10 promoted SHR-VMSCs proliferation and migration. Overexpression of miR-145-5p or knocking down of FGF10 after overexpresion of lncRNA TUG1 could rescue the proliferation and migration promoted by lncRNA TUG1. LncRNA TUG1 and FGF10 promoted and miR-145-5p suppressed the expression of β-catenin, TCF and LEF in SHR-VSMCs. Therefore, lncRNA TUG1/miR-145-5p/FGF10 promotes the proliferation and migration of VSMCs in hypertensive state by activating the Wnt/β-catenin pathway.

Long non-coding RNAs are emerging targets of phytochemicals for cancer and other chronic diseases

The long non-coding RNAs (lncRNAs) are the crucial regulators of human chronic diseases. Therefore, approaches such as antisense oligonucleotides, RNAi technology, and small molecule inhibitors have been used for the therapeutic targeting of lncRNAs. During the last decade, phytochemicals and nutraceuticals have been explored for their potential against lncRNAs. The common lncRNAs known to be modulated by phytochemicals include ROR, PVT1, HOTAIR, MALAT1, H19, MEG3, PCAT29, PANDAR, NEAT1, and GAS5. The phytochemicals such as curcumin, resveratrol, sulforaphane, berberine, EGCG, and gambogic acid have been examined against lncRNAs. In some cases, formulation of phytochemicals has also been used. The disease models where phytochemicals have been demonstrated to modulate lncRNAs expression include cancer, rheumatoid arthritis, osteoarthritis, and nonalcoholic fatty liver disease. The regulation of lncRNAs by phytochemicals can affect multi-steps of tumor development. When administered in combination with the conventional drugs, phytochemicals can also produce synergistic effects on lncRNAs leading to the sensitization of cancer cells. Phytochemicals target lncRNAs either directly or indirectly by affecting a wide variety of upstream molecules. However, the potential of phytochemicals against lncRNAs has been demonstrated mostly by preclinical studies in cancer models. How the modulation of lncRNAs by phytochemicals produce therapeutic effects on cancer and other chronic diseases is discussed in this review.

Protective impacts of long noncoding RNA taurine-upregulated 1 against lipopolysaccharide-evoked injury in MRC-5 cells through inhibition of microRNA-127

BACKGROUND

Pneumonia is a respiratory disease, which is triggered by pathogenic microorganisms or physical/chemical factors. Increasing evidence confirmed the vital impacts of long noncoding RNAs on various inflammatory diseases. Nonetheless, the influence of taurine-upregulated 1 (TUG1) in pneumonia remains vague. The research tried to disclose the protective impacts of TUG1 against lipopolysaccharide (LPS)-evoked injury in MRC-5 cells.

METHODS

MRC-5 cells were disposed with LPS to construct pulmonary injury model. Then, pc-TUG1 vector was transfected into MRC-5 cells and the influence of overexpressed TUG1 in cell viability, apoptosis, and pro-inflammatory cytokines in LPS-disposed cells were evaluated. The correlation between TUG1 and microRNA (miR)-127 was estimated via utilizing real-time quantitative polymerase chain reaction (RT-qPCR), meanwhile whether miR-127 affected the impacts of TUG1 on LPS-injured MRC-5 cells was explored. Besides, NF-κB and p38MAPK pathways were evaluated to understand the dormant mechanisms.

RESULTS

LPS administration apparently evoked inflammatory injury in MRC-5 cells by restraining cell viability, accelerating apoptosis, and enhancing TNF-α and IL-6 productions. But, TUG1 lightened LPS-evoked pro-inflammatory response in MRC-5 cells. In addition, miR-127 was repressed by overexpressed TUG1, meanwhile the protective impacts of TUG1 against LPS-evoked inflammatory injury in MRC-5 cells were overturned by overexpressed miR-127. Finally, we disclosed that TUG1 hindered the activation of NF-κB and p38MAPK pathways via restraining miR-127.

CONCLUSIONS

These explorations testified that taurine-upregulated 1 (TUG1) protected MRC-5 cells against lipopolysaccharide (LPS)-evoked inflammatory injury via hindering miR-127/NF-κB/p38MAPK axis.

Expression of long noncoding RNAs in breast cancer in relation to reproductive factors and tumor characteristics

Long noncoding RNAs (lncRNA) regulate expressions of several cancer-related genes and pathways. Expression profiling of lncRNAs would pave the way for identification of dysregulated pathways in cancer. We assessed expression of FAS-anti sense 1 (FAS-AS1), Taurine Upregulated 1 (TUG1), OPA-interacting protein 5-AS1 (OIP5 -AS1), nuclear-enriched abundant transcript 1 (NEAT1), and highly upregulated in liver cancer (HULC) in breast tumor tissues and adjacent noncancerous tissues (ANCTs). TUG1 was downregulated in tumoral tissues. We found associations between TUG1 expression and mitotic rate, NEAT1 expression and breast feeding duration as well as FAS-AS1 and OPI5 expressions and menarche age. A combination of transcript levels of all genes had 88.5% sensitivity and 42.3% specificity in breast cancer diagnosis. The current study provides evidence for the contribution of lncRNAs in breast cancer in relation to reproductive factors and tumor characteristics.

Taurine-upregulated gene 1: A functional long noncoding RNA in tumorigenesis

Taurine-upregulated gene 1 (TUG1) is a 7.1 kb long noncoding RNA (lncRNA) first recognized in 2005 as an important element for retinal development in rodents. Subsequently, this lncRNA has been shown to participate in oncogenic processes through alteration in chromatin structure, sponging microRNAs, and affecting the expression of some cancer-related pathways. While most of the studies have revealed an oncogenic role for this lncRNA, some reports have shown downregulation of TUG1 in lung cancer samples compared with noncancerous samples. In triple negative breast cancer samples, the expression of this lncRNA has been decreased. Besides, its expression has been higher in HER2-enriched and basal-like subtypes compared with luminal A. In the current review, we discuss the latest literature about the expression pattern and functional roles of TUG1 in diverse cancer types. In addition, its role in epithelial-mesenchymal transition and activation of Wnt/β-catenin pathway in human malignancies will be explored.

Taurine-upregulated gene 1 contributes to cancers through sponging microRNA

Long non-coding RNAs (lncRNAs) are a class of RNAs whose transcripts are more than 200 nucleotides in length and lack protein-coding ability. Taurine-upregulated gene 1 (TUG1), a novel cancer-related lncRNA, has been documented to be abnormally expressed in various types of cancers and act as an oncogene or anti-oncogene. It has been considered previously that TUG1 is closely related to the cell proliferation, invasion, metastasis, and apoptosis of cancer. In recent years, it has been found that TUG1 acts as a microRNA (miRNA) sponge to indirectly regulate the expression of the miRNA target gene and dominates cancer progression in several types of cancers. However, TUG1 also binds to different miRNAs to produce diverse regulatory mechanisms in the same cancer. TUG1 is expected to be a biomarker and a new therapeutic target for the diagnosis and prognosis of certain cancers. In this review, we highlight the up-to-date original studies that focus on the role of TUG1 sponging miRNA in cancers and summarize the function of TUG1 in cancer progression. The novel TUG1-miRNA regulatory network is comprehensively and minutely included in this review. We hope that this review will help readers obtain a more detailed knowledge of the molecular mechanism by which TUG1 sponging miRNA plays its role in cancers, and provide some insights and directions for future cancer research.

LncRNA TUG1 promotes cells proliferation and inhibits cells apoptosis through regulating AURKA in epithelial ovarian cancer cells

This study aimed to assess the effect of long noncoding RNAs (lncRNAs) taurine-upregulated gene 1 (TUG1) on cells proliferation and apoptosis as well as its targeting genes in epithelial ovarian cancer (EOC) cells.Blank mimic, lncRNA TUG1 mimic, blank inhibitor, and lncRNA TUG1 inhibitor plasmids were transfected into SK-OV-3 (SKOV3) cells. Rescue experiment was performed by the transfection of lncRNA TUG1 inhibitor and Aurora kinase A (AURKA) mimic plasmids into SKOV3 cells. Cell counting kit-8 (CKK-8), annexin V-FITC (AV)-propidium iodide (PI) (AV-PI), quantitative polymerase chain reaction (qPCR), and western blot assays were performed to detect cells proliferation, apoptosis, RNA expression, and protein expression respectively.Cells proliferation was increased in lncRNA TUG1 mimic group and decreased in lncRNA TUG1 inhibitor group than normal control (NC) groups. Cells apoptosis rate was repressed after treatment with lncRNA TUG1 mimic and promoted after treatment with lncRNA TUG1 inhibitor. AURKA expression but not CLDN3, SERPINE1, or ETS1 expression was adversely regulated by lncRNA TUG1 mimic and inhibitor. After transferring lncRNA TUG1 (-) and AURKA (+) plasmids, cells proliferation was increased, while cells apoptosis rate was decreased in AURKA mimic (+)/lncRNA TUG1 inhibitor (-) group than NC (+)/lncRNA TUG1 (-) group, which suggested lncRNA TUG1 regulated cells proliferation and cells apoptosis through targeting AURKA.LncRNA TUG1 promotes cells proliferation and inhibits cells apoptosis through regulating AURKA in EOC cells.

Long non-coding RNA HOTAIR promotes tumorigenesis and forecasts a poor prognosis in cholangiocarcinoma

Cholangiocarcinoma (CCA) arising from the neoplastic transformation of cholangiocytes with increasing incidence in the worldwide. Unfortunately, a large amount of CCA patients lost their chance for surgery because it is hard to diagnose in the early stages. Long non-coding RNAs (lncRNAs) is closely associated with development and progression of various malignant tumors. Hox transcript antisense intergenic (HOTAIR), a negative prognostic factor for patients with gastric, liver and pancreatic carcinoma. Its transcription levels and functional roles in CCA is still unknown. Therefore, we aimed to explore the effect of HOTAIR in CCA including cell proliferation, apoptosis, migration, invasion and epithelial-to-mesenchymal transition (EMT). The results showed that HOTAIR was highly expressed both in CCA tissue samples and cell lines compared with corresponding normal bile duct tissues and Human intrahepatic biliary epithelial cells (HIBEC). Its overexpression was closely correlated with Tumor size, TNM stage and postoperative recurrence in CCA patients. Moreover, up-regulation of HOTAIR has correlation with prognosis in CCA patients. Knockdown of HOTAIR by siRNAs significantly decreased the migration and invasion but increased apoptosis of CCA cells in vitro. Overall, our study revealed that HOTAIR may play as a new potential therapeutic target and forecast poor prognosis for this fatal disease.

Long non-coding RNA TUG1 sponges miR-197 to enhance cisplatin sensitivity in triple negative breast cancer

Breast cancer is the leading cause of women death worldwide. Several long non-coding RNAs (lncRNAs) have been identified as oncogenes or tumor suppressors during the progression of cancers. However, the role of taurine upregulated gene (TUG1) in mediating the chemotherapy sensitivity of triple negative breast cancer (TNBC) has not been studied yet. In TNBC patients, we observed a significant decrease of TUG1 in tumor tissues compared to the normal tissues. Similarly, TUG1 expression was significantly decreased in TNBC cell lines compared with normal breast epithelial cell line and cell lines of other subtypes of breast cancer. In MDA-MB-231 and BT549, cisplatin induced cell growth arrest was remarkably augmented by overexpression of TUG1 and was significantly reduced by TUG1 silencing. Moreover, very low concentration of cisplatin caused cell proliferation inhibition in TUG1-overexpressed-TNBC cells. In addition, we found that TUG1 negatively regulated miR-197 expression in the tested TNBC cell lines. Sponging of TUG1 to miR-197 was proved by a dual luciferase reporter assay. We further predicted and validated that nemo-like kinase (NLK), which was positively controlled by TUG1, was a target gene of miR-197. Via regulation of miR-197/NLK, TUG1 inactivated WNT signaling pathway and thus increasing chemotherapy sensitivity of TNBC cells. Analysis of TCGA database showed that higher expression of TUG1 was associated with better prognosis in breast cancer patients. Our current study drew a preliminary conclusion that TUG1 was involved in chemotherapy sensitivity in TNBC cells.

Selection of Metastatic Breast Cancer Cell-Specific Aptamers for the Capture of CTCs with a Metastatic Phenotype by Cell-SELEX

Circulating tumor cells (CTCs) have the potential to predict metastasis, and the capture of CTCs based on their surface markers is mostly applied for CTC detection. Considering that the CTCs with a metastatic phenotype preferably form a metastatic focus and that aptamers have the ability to bind targets with high specificity and affinity, we selected aptamers directed toward metastatic cells by subtractive Cell-SELEX technology using highly metastatic MDA-MB-231 cells as the target cell and low-metastatic MCF-7 cells as the negative cell for the capture of metastatic CTCs. Affinity and selectivity assays showed that aptamer M3 had the highest affinity, with a K_D of 45.6 ± 1.2 nM, and had good specificity against several other types of metastatic cancer cells. Based on these findings, we developed an M3-based capture system for CTC enrichment, which has the capability to specifically capture the metastatic cells MDA-MB-231 mixed with non-metastatic MCF-7 cells and CTCs derived from the peripheral blood from metastatic breast cancer patients. A further comparative analysis with the anti-EpCAM probe showed that M3 probe captured epithelial feature-deletion metastatic cells. We developed an aptamer-based CTC capture system through the selection of aptamers by taking whole metastatic cells, not known molecules, as targets, which provided a new insight into CTC capture and Cell-SELEX application.

The Impact of lncRNA Dysregulation on Clinicopathology and Survival of Breast Cancer: A Systematic Review and Meta-analysis

Dysregulation of multiple long non-coding RNAs (lncRNAs) was reported to play major roles in breast cancer (BC). Here we aimed to collect most of the relevant literature to assess the prognostic value of lncRNAs in BC. To this end, we systematically searched PubMed, Embase, Web of Science, Chinese National Knowledge Infrastructure (CNKI), and Wanfang to identify published articles on the associations of lncRNAs with clinicopathology and/or survival of BC. Via this searching, we identified 70 articles involving 9,307 BC patients and regarding 48 lncRNAs. The expression of 41 lncRNAs was related to one or more clinicopathological parameters of BC, including tumor size; lymph node metastasis; histological grade; TNM stage; and estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER-2) statuses (p < 0.05). Dysregulation of 28 lncRNAs was associated with overall survival, and abnormal expression of 9 lncRNAs was linked to disease-free survival. Furthermore, the expression level of 3 lncRNAs was correlated with metastasis-free survival, 3 lncRNAs with relapse-free survival, and 3 lncRNAs with progression-free survival. Our analysis showed that multiple lncRNAs were significantly associated with BC clinicopathology and survival. A large-scale study is needed to verify the prognostic value of these lncRNAs in BC.

Long non-coding RNA taurine-upregulated gene 1 predicts unfavorable prognosis, promotes cells proliferation, and inhibits cells apoptosis in epithelial ovarian cancer

The aim of this study was to evaluate the correlation of long non-coding RNAs (lncRNAs) taurine-upregulated gene 1 (TUG1) with clinicopathological characteristics as well as overall survival (OS) in epithelial ovarian cancer (EOC) patients, and investigate its function in EOC cells proliferation and apoptosis in vitro.LncRNA TUG1 expressions were detected in tumor tissues and paired adjacent tissues obtained from 96 EOC patients. Blank mimic, lncRNA TUG1 mimic, blank inhibitor, and lncRNA TUG1 inhibitor plasmids were transfected into SKOV3 cells. CKK-8, annexin V-FITC-propidium iodide, qPCR and western blot assays were performed to detect cells proliferation, cells apoptosis, RNA expression, and protein expression, respectively.LncRNA TUG1 expression was higher in tumor tissue compared to paired adjacent tissue (P < .001), and it was positively correlated with pathological grade (P = .022), tumor size (P = .011) and FIGO stage (P < .001). Kaplan-Meier curve showed that lncRNA TUG1 high expression was associated with worse OS (P = .003). Multivariate Cox analysis indicated that lncRNA TUG1 high expression (vs. low expression) (P = .035) was independently predictive factor for shorter OS. In vitro, cells proliferation was promoted after treatment with lncRNA TUG1 mimic and was suppressed after treatment with lncRNA TUG1 inhibitor. In addition, cells apoptosis rate was decreased in lncRNA TUG1 mimic group compared to NC1 mimic, and increased in lncRNA TUG1 inhibitor group compared to NC2 inhibitor.In conclusion, lncRNA TUG1 is positively correlated with advanced disease and poor prognosis, and it promotes cells proliferation and inhibits cells apoptosis in EOC cells.

Long non-coding RNA taurine-upregulated gene 1 correlates with poor prognosis, induces cell proliferation, and represses cell apoptosis via targeting aurora kinase A in adult acute myeloid leukemia

This study aimed to investigate the correlation of long non-coding RNA (lncRNA) taurine-upregulated gene 1 (TUG1) with clinicopathological feature and prognosis, and to explore its effect on cell proliferation and apoptosis as well as the relevant target genes in adult acute myeloid leukemia (AML). LncRNA TUG1 expression was detected in bone marrow samples from 186 AML patients and 62 controls. Blank mimic, lncRNA TUG1 mimic, blank inhibitor, and lncRNA TUG1 inhibitor lentivirus vectors were transfected in KG-1 cells. Rescue experiment was performed by transfection of lncRNA TUG1 inhibitor and aurora kinase A (AURKA) mimic lentivirus vectors. Cell proliferation, apoptosis, RNA, and protein expressions were determined by CKK-8, annexin V-FITC-propidium iodide, quantitative polymerase chain reaction, and western blot assays. LncRNA TUG1 expression was higher in AML patients compared to controls and correlated with higher white blood cell counts, monosomal karyotype, FLT3-ITD mutation, poor-risk stratification, and poor prognosis, which independently predicted worse event-free survival and overall survival. In vitro, lncRNA TUG1 expression was higher in AML cell lines (KG-1, MOLM-14, HL-60, NB-4, and THP-1 cells) compared to controls. LncRNA TUG1 mimic promoted cell proliferation and decreased cell apoptosis rate, while lncRNA TUG1 inhibitor repressed cell proliferation and increased cell apoptosis rate. Rescue experiment showed that AURKA attenuated the influence of lncRNA TUG1 on AML cell proliferation and apoptosis. In conclusion, lncRNA TUG1 associates with advanced disease and worse prognosis in adult AML patients, and it induces AML cell proliferation and represses cell apoptosis via targeting AURKA.

Long Non-Coding RNA TUG1 Expression Is Associated with Different Subtypes in Human Breast Cancer

Taurine upregulated 1 gene (TUG1) is a long non-coding RNA associated with several types of cancer. Recently, differential expression of TUG1 was found in cancerous breast tissues and associated with breast cancer malignancy features. Although this is evidence of a potential role in breast cancer, TUG1 expression could not be associated with different subtypes, possibly due to the small number of samples analyzed. Breast cancer is a heterogeneous disease and, based on molecular signatures, may be classified into different subtypes with prognostic implications. In the present study, we include analysis of TUG1 expression in 796 invasive breast carcinoma and 105 normal samples of RNA sequencing (RNA-seq) datasets from The Cancer Genome Atlas (TCGA) and describe that TUG1 expression is increased in HER2-enriched and basal-like subtypes compared to luminal A. Additionally, TUG1 expression is associated with survival in HER2-enriched patients. These results reinforce the importance of TUG1 in breast cancer and outline its potential impact on specific subtypes.

LncRNA expression and implication in osteosarcoma: a systematic review and meta-analysis

Purpose

Osteosarcoma is the most prevalent primary bone tumor in children, adolescents, and older adults, typically presenting with poor survival outcomes. In recent years, ample evidence has shown that many long noncoding RNAs (lncRNAs) have been aberrantly expressed in osteosarcoma, demonstrating their potential to serve as prognostic markers. In this study, we performed a meta-analysis on four lncRNAs (TUG1, UCA1, BCAR4, and HULC) to systematically evaluate their prognostic value in osteosarcoma.

Materials and methods

The eligible articles were systematically searched in PubMed, Web of Science, Embase, and Elsevier ScienceDirect (up to September 22, 2017), and one meta-analysis concerning the association between lncRNA expression and the overall survival (OS) of osteosarcoma patients was performed. Survival outcomes were analyzed by OS. Subgroup analyses were performed.

Results

A total of 1,361 patients with osteosarcoma and 12 lncRNAs from 16 articles were included in the study. Of the listed lncRNAs, the high expression of 10 lncRNAs indicated worse survival outcomes, while only two lncRNAs were shown to positively affect patients’ OS.

Conclusion

This meta-analysis indicated that the abnormally expressed lncRNAs might significantly affect the survival of osteosarcoma patients. Combined use of these lncRNAs may serve as potential novel biomarkers for the indication of clinical outcomes of osteosarcoma patients as well as the selection of adjuvant chemotherapy strategies for clinical treatment of this disease.

LncRNA TUG1 sponges miR-145 to promote cancer progression and regulate glutamine metabolism via Sirt3/GDH axis

Long noncoding RNAs (lncRNAs) are important regulators in cancer progression. Deregulation of the lncRNA taurine upregulated gene 1 (TUG1) predicts poor prognosis and is implicated in the development of several cancers. In this study, we investigated the role of TUG1 in the pathogenesis of intrahepatic cholangiocarcinoma (ICC). We found that TUG1 is upregulated in ICC samples, which correlates with poor prognosis and adverse clinical pathological characteristics. Knockdown of TUG1 inhibited the proliferation, motility, and invasiveness of cultured ICC cells, and decreased tumor burden in a xenograft mouse model. When we explored the mechanisms underlying these effects, we found that TUG1 acts as an endogenous competing RNA (ceRNA) that ‘sponges’ miR-145, thereby preventing the degradation of Sirt3 mRNA and increasing expression of Sirt3 and GDH proteins. Accordingly, glutamine consumption, α-KG production, and ATP levels were dramatically decreased by TUG1 knockdown in ICC cells, and this effect was reversed by miR-145 inhibition. These findings indicate that the TUG1/miR-145/Sirt3/GDH regulatory network may provide a novel therapeutic strategy for treatment of ICC.

Long non-coding RNAs as an epigenetic regulator in human cancers

Recent studies have described the important multiple roles of long non‐coding RNAs (lncRNAs) during oncogenic transformation. Because the coding genome accounts for a small amount of total DNA, and many mutations leading to cancer occur in the non‐coding genome, it is plausible that the dysregulation of such non‐coding transcribes might also affect tumor phenotypes. Indeed, to date, lncRNAs have been reported to affect diverse biological processes through the regulation of mRNA stability, RNA splicing, chromatin structure, and miRNA‐mediated gene regulation by acting as miRNA sponges. Furthermore, accumulating studies have described the roles of lncRNAs in tumorigenesis; however, the precise mechanisms of many lncRNAs are still under investigation. Here, we discuss recently reported mechanistic insights into how lncRNAs regulate gene expression and contribute to tumorigenesis through interactions with other regulatory molecules. We especially highlight the role of taurine upregulated gene 1, which was recently reported to have biological functions related to gene regulation, and discuss the future clinical implications of lncRNAs in cancer treatments.

Prognostic value of long non-coding RNA TUG1 in various tumors

Taurine up-regulated gene 1 (TUG1) is a long non-coding RNA (lncRNA), has been reported that be dysregulated in various tumors, involved in proliferation and apoptosis in a variety of tumor cells. To detect the clinical significance of TUG1 expression in tumor patients, we carried out current systematic review and meta-analysis investigating its relation with the prognosis and clinicopathological features of cancers. A total of 15 studies comprise 1560 patients were analyzed. The pooled results showed that no significant relationship between high TUG1 expression and overall survival (OS) (HR = 1.28, 95% CI: 0.96–1.69, P = 0.091) in various tumors. In the subgroup analysis by cancer type, elevated TUG1 expression was associated with poorer survival in cancer patients with high TUG1 expression subgroup but better survival in patients with low TUG1 expression subgroup. Over-expression of TUG1 associated with significantly unfavorable survival for bladder cancer (HR=2.67, 95% CI: 1.47–4.87, P = 0.001). Up-regulation of TUG1 correlated with distant metastasis (DM) (OR = 4.22, 95% CI: 2.66–6.70, P < 0.001) and tumor differentiation (OR = 2.45, 95% CI: 1.28–4.70, P = 0.007), but failed to show inline to gender (OR = 1.04, 95% CI: 0.77–1.42, P = 0.774), age (OR = 0.75, 95% CI: 0.51–1.10, P = 0.136), lymph node metastasis (LNM) (OR = 1.45, 95% CI: 0.85–2.50, P = 0.177), and TNM stage (OR = 0.55, 95% CI: 0.17–1.81, P = 0.326). The overall results suggest lncRNA TUG1 may be a useful prognostic biomarker in cancer patients.

The prognostic potential and carcinogenesis of long non-coding RNA TUG1 in human cholangiocarcinoma

Cholangiocarcinoma (CCA) is a fatal disease with increasing worldwide incidence and is characterized by poor prognosis due to its poor response to conventional chemotherapy or radiotherapy. Long non-coding RNAs (lncRNAs) play key roles in multiple human cancers, including CCA. Cancer progression related lncRNA taurine-up-regulated gene 1 (TUG1) was reported to be involved in human carcinomas. However, the impact of TUG1 in CCA is unclear. The aim of this study was to explore the expression pattern of TUG1 and evaluate its clinical significance as well as prognostic potential in CCA. In addition, the functional roles of TUG1 including cell proliferation, apoptosis, migration, invasion and epithelial-mesenchymal transition (EMT), were evaluated after TUG1 silencing. Our data demonstrated up-regulation of TUG1 in both CCA tissues and cell lines. Moreover, overexpression of TUG1 is linked to tumor size (p=0.005), TNM stage (p=0.013), postoperative recurrence (p=0.036) and overall survival (p=0.010) of CCA patients. Furthermore, down-regulation of TUG1 following RNA silencing reduced cell growth and increased apoptosis in CCA cells. Additionally, TUG1 suppression inhibited metastasis potential in vitro by reversing EMT. Overall, our results suggest that TUG1 may be a rational CCA-related prognostic factor and therapeutic target.

Long non-coding RNA TUG1 as a potential prognostic biomarker in human cancers: a meta-analysis

LncRNA taurine upregulated gene 1 (TUG1) is reportedly dysregulated in various cancers. We performed this meta-analysis to clarify the usefulness of TUG1 as a prognostic marker in malignant tumors. The PubMed, Medline, OVID, Cochrane Library, and Web of Science databases were searched from inception to Jan 11, 2017. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated to explore the relationship between TUG1 expression and overall survival (OS). Odds ratios (ORs) were calculated to assess the association between TUG1 expression and pathological parameters. Thirteen original studies covering 1,274 cancer patients were included in this meta-analysis. The pooled HR suggested that high TUG1 expression correlated with poor OS (pooled HR=1.41, 95% CI: 1.01-1.98) in cancer types other than non-small cell lung cancer. TUG1 expression was also related to distant metastasis (OR=3.24, 95% CI: 1.18-8.93), large tumor size (OR=4.07, 95% CI: 1.08-15.28) and advanced tumor stage (OR=3.45, 95% CI: 2.19-5.44). Begg’s funnel plot and Egger’s test showed no evidence of obvious asymmetry for overall survival or tumor stage. Thus high TUG1 expression appears predictive of poor OS, distant metastasis, advanced tumor stage and large tumor size. This suggests TUG1 expression could serve as a biomarker for poor prognosis in cancers.

Prognostic and clinicopathological role of long non-coding RNA taurine upregulated 1 in various human malignancies: A systemic review and meta-analysis

The aberrant dysregulation of taurine upregulated 1, a novel discovered long non-coding RNA, was ubiquitous in different human solid tumors. Accumulating researches have indicated that taurine upregulated 1 is an independent prognostic indicator in cancer patients. This investigation aimed to further explore the prognostic and clinical significance of taurine upregulated 1 in various types of cancers. Eligible studies were systematically searched in PubMed, Embase, Medline, and Web of Science databases. A total of 12/14 studies with 1303/1228 individuals were included to evaluate the association of taurine upregulated 1 with overall survival and clinicopathological features by pooled hazard ratio and odds ratio in malignancies. The meta-analysis suggested overexpression of taurine upregulated 1 was significantly correlated with unfavorable overall survival in patients with cancer (pooled hazard ratio = 1.63, 95% confidence interval: 1.29-2.06). There was also a significantly positive correlation between high level of taurine upregulated 1 and high pathological grade carcinoma (pooled odds ratio = 4.41, 95% confidence interval: 3.07-6.43) and positive lymphatic metastasis (pooled odds ratio = 2.00, 95% confidence interval: 1.31-3.06). In summary, upregulated taurine upregulated 1 is correlated with more advanced clinicopathological characteristics and poor prognosis, suggesting that taurine upregulated 1 may serve as a novel predictive biomarker of patients with numerous tumors.