Long non-coding RNA TUG1 promotes osteosarcoma cell proliferation and invasion through inhibition of microRNA-212-3p expression

Role of long noncoding RNA taurine-upregulated gene 1 in cancers

Long non-coding RNAs (lncRNAs) are a group of non-protein coding RNAs with a length of more than 200 bp. The lncRNA taurine up-regulated gene 1 (TUG1) is abnormally expressed in many human malignant cancers, where it acts as a competitive endogenous RNA (ceRNA), regulating gene expression by specifically sponging its corresponding microRNAs. In the present review, we summarised the current understanding of the role of lncRNA TUG1 in cancer cell proliferation, metastasis, angiogenesis, chemotherapeutic drug resistance, radiosensitivity, cell regulation, and cell glycolysis, as well as highlighting its potential application as a clinical biomarker or therapeutic target for malignant cancer. This review provides the basis for new research directions for lncRNA TUG1 in cancer prevention, diagnosis, and treatment.

The potential role of lncRNAs in osteoporosis

Osteoporosis is a common bone disease characterized by low bone mass and deterioration of bone microstructure, which predisposes to higher risks of bone fragility and bone fracture. Long non-coding RNAs (lncRNAs) are a class of RNAs with a length of > 200 nucleotides without protein-coding function, which control the expression of genes and affect multiple biological processes. Accumulating evidence suggests that lncRNAs are widely involved in the molecular mechanisms of osteoporosis. This review aims to summarize the function and underlying mechanism of lncRNAs involved in the development of osteoporosis, and how it contributes to osteoblast and osteoclast function. This knowledge will shed new light on the modulation and potential treatment of osteoporosis.

The Involvement of Long Non-Coding RNAs in Bone

A harmonious balance between osteoblast and osteoclast activity guarantees optimal bone formation and resorption, pathological conditions affecting the bone may arise. In recent years, emerging evidence has shown that epigenetic mechanisms play an important role during osteoblastogenesis and osteoclastogenesis processes, including long non-coding RNAs (lncRNAs). These molecules are a class of ncRNAs with lengths exceeding 200 nucleotides not translated into protein, that have attracted the attention of the scientific community as potential biomarkers to use for the future development of novel diagnostic and therapeutic approaches for several pathologies, including bone diseases. This review aims to provide an overview of the lncRNAs and their possible molecular mechanisms in the osteoblastogenesis and osteoclastogenesis processes. The deregulation of their expression profiles in common diseases associated with an altered bone turnover is also described. In perspective, lncRNAs could be considered potential innovative molecular biomarkers to help with earlier diagnosis of bone metabolism-related disorders and for the development of new therapeutic strategies.

Long non-coding RNA MIAT promotes the proliferation and invasion of laryngeal squamous cell carcinoma cells by sponging microRNA-613

Accumulating evidence indicates that the long non-coding RNA myocardial infarction associated transcript (lncRNA MIAT) serves an important role in the progression of a number of cancer types. However, the precise molecular mechanism of MIAT in laryngeal squamous cell carcinoma (LSCC) progression remain elusive. The aim of the current study was to assess the effects and to clarify the molecular mechanism of MIAT on the proliferation and invasion of LSCC cells. The expression of MIAT was detected in LSCC tissues and cells using reverse transcription-quantitative PCR. MTT and colony formation assays were performed to examine the effects of MIAT on the proliferation of LSCC cells. Additionally, wound healing and Transwell experiments were employed to examine cellular migration and invasion. Luciferase reporter gene assay was also used to confirm the direct binding between MIAT and microRNA (miR)-613 in LSCC cells. An RNA immunoprecipitation assay was performed to verify the interaction between MIAT and miR-613. In the present study, it was found that the expression of MIAT in LSCC tissues was markedly higher compared with that in adjacent non-tumor tissues. In addition, MIAT expression was also increased in the human LSCC cell lines TU686, TU-177 and AMC-HN-8 compared with that in normal human keratinocytes (HaCaT). Knocking down MIAT expression significantly reduced LSCC cell proliferation and inhibited colony formation, a shown by MTT and colony formation assays, respectively. MIAT knockdown also substantially inhibited the migratory and invasive abilities of LSCC cells, as shown by wound healing and Transwell invasion assays, respectively. Subsequently, luciferase reporter assays verified that MIAT could bind to miR-613, where a negative correlation was observed between the expression of MIAT and miR-613 in LSCC tissues. Suppression of miR-613 partially reversed the inhibitory effects of MIAT knockdown on the proliferation, migration and invasion of LSCC cells. Taken together, the present study identified that MIAT may function as an oncogenic lncRNA to promote LSCC progression, which provides a potential therapeutic target or as a novel diagnostic biomarker for LSCC.

LncRNA TUG1 promotes the intervertebral disc degeneration and nucleus pulposus cell apoptosis though modulating miR-26a/HMGB1 axis and regulating NF-κB activation

AIMS

This study was to investigate the effect of TUG1 on apoptosis and ECM degradation of human degenerative intervertebral disc nucleus pulposus cells (NPCs) and its mechanism.

METHODS

Human degenerative intervertebral disc NP tissues were obtained from 10 patients with lumbar disc herniation (LDH) who underwent lumbar spine surgery (IDD group), normal intervertebral disc NP tissues were obtained from 10 patients with lumbar vertebrae fractures (LVF group).

RESULTS

The expression of TUG1 and HMGB1 protein in human degenerative disc NP tissues and NPCs was significantly increased, while the level of miR-26a was significantly decreased. Overexpression of TUG1 inhibited the proliferation while promoted apoptosis and ECM degradation of human degenerative intervertebral disc NPCs. Simultaneously, the effect of TUG1 knockdown on NPCs was opposite. Interestingly, TUG1 acted as an endogenous sponge to down-regulate the expression of miR-26a in NPCs by direct binding to miR-26a. Overexpression of miR-26a reversed the effects of TUG1 overexpression on apoptosis and ECM degradation. Additionally, HMGB1 was a target gene of miR-26a. The increased expression of HMGB1 induced by TUG1 overexpression could be reversed by the introduction of miR-26a mimic. Overexpression of TUG1 significantly upregulated the expression of p65 in the nucleus, while overexpression of TUG1 partially abolished the inhibition of NF-κB by QNZ pretreatment.

CONCLUSION

TUG1 could promote the apoptosis and ECM degradation of degenerated intervertebral disc NPCs by regulating the miR-26a/HMGB1, which may be involved in the activation of NF-κB pathway.

Long Noncoding RNA TUG1 Promotes Autophagy-Associated Paclitaxel Resistance by Sponging miR-29b-3p in Ovarian Cancer Cells

Purpose

Paclitaxel (PTX) is a first-line chemotherapeutic agent for treating ovarian cancer. However, PTX resistance has become a major obstacle in ovarian cancer therapy. The underlying mechanism associated with PTX resistance is still unclear.

Patients and Methods

We used qPCR to detect taurine up-regulated 1 (TUG1) expression in normal ovarian tissues and ovarian tumor tissues. A combination of small interfering RNA (siRNA), cell counting kit 8 (CCK8), colony formation assay and nude mouse model were used to detect the effect of TUG1 on ovarian cancer cell PTX-resistance. Autophagy/cytotoxicity dual staining assay, luciferase reporter assay, Western blot and RNA-binding protein immunoprecipitation assay were used for further mechanistic studies.

Results

TUG1 is highly expressed not only in ovarian tumor tissues compared with normal ovarian tissues but also in the chemo-resistant group compared with the sensitive group. Knockdown of TUG1 by siRNA decreased ovarian cancer cell and xenograft tumor PTX resistance with or without PTX treatment. Moreover, deletion of TUG1 in ovarian cancer cells decreased autophagosome formation and increased apoptosis as demonstrated by autophagy/cytotoxicity dual staining and Western blot assays. Furthermore, microRNA-29b-3p (miR-29b-3p) was found as the direct target of TUG1. Additionally, TUG1 could directly bind Ago2, a key protein of the RNA-induced silencing complex.

Conclusion

Our findings suggest that TUG1, through targeting miR-29b-3p, induces autophagy and consequently results in PTX resistance in ovarian cancer.

Identification and Validation of a Potent Multi-miRNA Signature for Prediction of Prognosis of Osteosarcoma Patients

Background

Osteosarcoma, the most common solid malignancy, has high incidence and mortality rates. We constructed a miRNA-based signature that can be used to assess the prognosis of osteosarcoma patients.

Material/Methods

The miRNA profile was derived from the Gene Expression Omnibus (GEO) website, with matched clinical records. The miRNA-based overall survival (OS)-predicting signature was established by LASSO Cox regression analysis. Receiver operating characteristic (ROC) curve and Kaplan-Meier (K-M) analyses were performed to examine the stability and discriminatory ability of the OS-predicting signatures. Pathway enrichment analyses were performed to uncover potential mechanisms.

Results

Three miRNAs (miR-153, miR-212, and miR-591) independently related to the OS were extracted to build a risk score formula. The ROC curve and K-M analyses revealed good discrimination ability of the OS signature for osteosarcoma patients in both the training cohort (P=0.00015, AUC=0.962) and the validation cohort (P=0.0065, AUC=0.793). As shown in multivariate analysis, the classifier showed favorable predictive accuracy similar to the recurrence status to be an independent risk factor for osteosarcoma. Furthermore, the nomogram showed a synergistic effect by combining the clinicopathological features with our classifier. Also, the enrichment analyses of the target genes may contribute to improved treatment of osteosarcoma.

Conclusions

The 3-miRNA-based classifier serves as an effective prognosis-predicting signature for osteosarcoma patients.

Non-Coding RNAs in Pediatric Solid Tumors

Pediatric solid tumors are a diverse group of extracranial solid tumors representing approximately 40% of childhood cancers. Pediatric solid tumors are believed to arise as a result of disruptions in the developmental process of precursor cells which lead them to accumulate cancerous phenotypes. In contrast to many adult tumors, pediatric tumors typically feature a low number of genetic mutations in protein-coding genes which could explain the emergence of these phenotypes. It is likely that oncogenesis occurs after a failure at many different levels of regulation. Non-coding RNAs (ncRNAs) comprise a group of functional RNA molecules that lack protein coding potential but are essential in the regulation and maintenance of many epigenetic and post-translational mechanisms. Indeed, research has accumulated a large body of evidence implicating many ncRNAs in the regulation of well-established oncogenic networks. In this review we cover a range of extracranial solid tumors which represent some of the rarer and enigmatic childhood cancers known. We focus on two major classes of ncRNAs, microRNAs and long non-coding RNAs, which are likely to play a key role in the development of these cancers and emphasize their functional contributions and molecular interactions during tumor formation.

Silver, Gold, and Iron Oxide Nanoparticles Alter miRNA Expression but Do Not Affect DNA Methylation in HepG2 Cells

The increasing use of nanoparticles (NPs) in various applications entails the need for reliable assessment of their potential toxicity for humans. Originally, studies concerning the toxicity of NPs focused on cytotoxic and genotoxic effects, but more recently, attention has been paid to epigenetic changes induced by nanoparticles. In the present research, we analysed the DNA methylation status of genes related to inflammation and apoptosis as well as the expression of miRNAs related to these processes in response to silver (AgNPs), gold (AuNPs), and superparamagnetic iron oxide nanoparticles (SPIONs) at low cytotoxic doses in HepG2 cells. There were no significant differences between treated and control cells in the DNA methylation status. We identified nine miRNAs, the expression of which was significantly altered by treatment with nanoparticles. The highest number of changes was induced by AgNPs (six miRNAs), followed by AuNPs (four miRNAs) and SPIONs (two miRNAs). Among others, AgNPs suppressed miR-34a expression, which is of particular interest since it may be responsible for the previously observed AgNPs-mediated HepG2 cells sensitisation to tumour necrosis factor (TNF). Most of the miRNAs affected by NP treatment in the present study have been previously shown to inhibit cell proliferation and tumourigenesis. However, based on the observed changes in miRNA expression we cannot draw definite conclusions regarding the pro- or anti-tumour nature of the NPs under study. Further research is needed to fully elucidate the relation between observed changes in miRNA expression and the effect of NPs observed at the cellular level. The results of the present study support the idea of including epigenetic testing during the toxicological assessment of the biological interaction of nanomaterials.

Long noncoding RNA TUG1 promotes proliferation and inhibits apoptosis in multiple myeloma by inhibiting miR-29b-3p

Background: Long non-coding RNA taurine up-regulated gene 1 (TUG1) was reportedly involved in initiation and development of several cancers. However, its function and molecular mechanisms in multiple myeloma (MM) are still unclear. The present study aimed to determine the expression status, biological function, and potential mechanisms of TUG1 in the progression of MM.

Materials and methods: The expression levels of TUG1 were examined in MM samples and cell lines by real-time quantitative PCR. The effects of TUG1 on MM cells proliferation and apoptosis were assessed using Cell Counting Kit-8 assay and flow cytometry respectively. MiRNAs-targeted sites in TUG1 were screened by Starbase2.0 and were identified by RNA immunoprecipitation assay combined with luciferase reporter assay.

Results: The expression levels of TUG1 were markedly increased in MM samples and cell lines. Knockdown of TUG1 significantly suppressed the proliferation, induced cell cycle arrest at G1/G0 phase, and promoted apoptosis of MM cells. In exploring the regulatory mechanism, miR-29b-3p was confirmed to be a direct target of TUG1, and repression of miR-29b-3p could partially rescue the effect TUG1 knockdown on MM cell proliferation, cycle, and apoptosis. In addition, TUG1 positively modulated histone deacetylases 4 (HDAC4, a target of miR-29b-3p) expression through sponging of miR-29b-3p in MM cells.

Conclusion: These findings suggested that TUG1 exerted an oncogenic role in MM by acting as a competing endogenous RNA of miR-29b-3p, and implied the potential application of TUG1 in treatment for MM.

Long Non-coding RNAs Contribute to the Inhibition of Proliferation and EMT by Pterostilbene in Human Breast Cancer

Background: There is increasing evidence that long non-coding RNAs (lncRNAs) are involved in the process of carcinogenesis and treatment using chemotherapy. Pterostilbene, a phytochemical agent with natural antioxidant and anti-inflammatory properties, has been shown to modulate oncogenic processes in many cancers. However, there has been limited research on the association between pterostilbene and the expression of lncRNAs.

Methods: MCF7 breast cancer cells were treated with various concentrations of pterostilbene and their gene expression profile was analyzed by quantitative real-time PCR, Western blotting and immunofluorescence.

Results: Treatment with pterostilbene inhibited cell proliferation and epithelial-to-mesenchymal transition (EMT), and increased cell apoptosis, autophagy and ER stress. The Akt/mTOR pathway was downregulated, but p38 MAPK/Erk signaling was activated in cells following treatment with pterostilbene. Pterostilbene increased the expression of the lncRNAs MEG3, TUG1, H19, and DICER1-AS1 whereas the expression of LINC01121, PTTG3P, and HOTAIR declined. Knockdown of lncRNA H19 resulted in a reduction of the cell invasion, with the cells becoming more sensitive to pterostilbene therapy.

Conclusions: These results suggest that efficient optimum disruption of lncRNA expression might possibly improve the anti-tumor effects of phytochemical agents, thus serving as a potential therapy for breast cancer.

Non-Coding RNA in Pancreas and β-Cell Development

In this review, we provide an overview of the current knowledge on the role of different classes of non-coding RNAs for islet and β-cell development, maturation and function. MicroRNAs (miRNAs), a prominent class of small RNAs, have been investigated for more than two decades and patterns of the roles of different miRNAs in pancreatic fetal development, islet and β-cell maturation and function are now emerging. Specific miRNAs are dynamically regulated throughout the period of pancreas development, during islet and β-cell differentiation as well as in the perinatal period, where a burst of β-cell replication takes place. The role of long non-coding RNAs (lncRNA) in islet and β-cells is less investigated than for miRNAs, but knowledge is increasing rapidly. The advent of ultra-deep RNA sequencing has enabled the identification of highly islet- or β-cell-selective lncRNA transcripts expressed at low levels. Their roles in islet cells are currently only characterized for a few of these lncRNAs, and these are often associated with β-cell super-enhancers and regulate neighboring gene activity. Moreover, ncRNAs present in imprinted regions are involved in pancreas development and β-cell function. Altogether, these observations support significant and important actions of ncRNAs in β-cell development and function.