MALAT1 — a paradigm for long noncoding RNA function in cancer

LncRNA MALAT1 prevents the protective effects of miR-125b-5p against acute myocardial infarction through positive regulation of NLRC5

Acute myocardial infarction (AMI), as the first manifestation of ischemic heart disease, is the most common cause of death in developed countries. A recent study showed that metastasis associated lung adenocarcinoma transcript 1 (MALAT1), a prognostic marker for lung cancer metastasis, could promote myocardial ischemia-reperfusion injury by regulating the levels of microRNA (miR)-145. In order to elucidate the biological function of MALAT1 in the pathogenesis of AMI and to explore the mechanisms underlying its action, an AMI rat model was established by ligation of the left anterior descending coronary artery. Downregulation of MALAT1 by siRNA transfection attenuated heart damage in an AMI model rat. The mouse cardiomyocyte cell line HL-1 was used to show that downregulation of nucleotide binding and oligomerization domain-like receptor C5 (NLRC5) and upregulation of miR-125b-5p were the results of MALAT1 silencing. TargetScan and a dual-luciferase reporter assay indicated that NLRC5 is a direct target of miR-125b-5p. Overexpression of miR-125b-5p significantly reduced hypoxia/reperfusion-induced apoptosis of HL-1 cells, an effect that could be blocked by NLCR5 overexpression. Taken together, these results suggest that MALAT1 reduced the protective effect of miR-125b-5p on injured cells through upregulation of NLCR5. This study highlights the role of MALAT1 in the pathogenesis of AMI and may guide future genetic therapeutic strategies for AMI treatment.

Roles of lncRNAs and circRNAs in regulating skeletal muscle development

The multistep biological process of myogenesis is regulated by a variety of myoblast regulators, such as myogenic differentiation antigen, myogenin, myogenic regulatory factor, myocyte enhancer factor2A-D and myosin heavy chain. Proliferation and differentiation during skeletal muscle myogenesis contribute to the physiological function of muscles. Certain non-coding RNAs, including long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), are involved in the regulation of muscle development, and the aberrant expressions of lncRNAs and circRNAs are associated with muscular diseases. In this review, we summarize the recent advances concerning the roles of lncRNAs and circRNAs in regulating the developmental aspects of myogenesis. These findings have remarkably broadened our understanding of the gene regulation mechanisms governing muscle proliferation and differentiation, which makes it more feasible to design novel preventive, diagnostic and therapeutic strategies for muscle disorders.

Transcriptome analysis reveals overlap in fusion genes in a phase I clinical cohort of TNBC and HGSOC patients treated with buparlisib and olaparib

PURPOSE

Fusion genes can be therapeutically relevant if they result in constitutive activation of oncogenes or repression of tumor suppressors. However, the prevalence and role of fusion genes in female cancers remain largely unexplored. Here, we investigate the fusion gene landscape in triple-negative breast cancer (TNBC) and high-grade serous ovarian cancer (HGSOC), two subtypes of female cancers with high molecular similarity but limited treatment options at present.

METHODS

RNA-seq was utilized to identify fusion genes in a cohort of 18 TNBC and HGSOC patients treated with the PI3K inhibitor buparlisib and the PARP inhibitor olaparib in a phase I clinical trial (NCT01623349). Differential gene expression analysis was performed to assess the function of fusion genes in silico. Finally, these findings were correlated with the reported clinical outcomes.

RESULTS

A total of 156 fusion genes was detected, whereof 44/156 (28%) events occurred in more than one patient. Low recurrence across samples indicated that the majority of fusion genes were private passenger events. The long non-coding RNA MALAT1 was involved in 97/156 (62%) fusion genes, followed in prevalence by MUC16, FOXP1, WWOX and XIST. Gene expression of FOXP1 was significantly elevated in patients with vs. without FOXP1 fusion (P= 0.02). From a clinical perspective, FOXP1 fusions were associated with a favorable overall survival.

CONCLUSIONS

In summary, this study provides the first characterization of fusion genes in a cohort of TNBC and HGSOC patients. An improved mechanistic understanding of fusion genes will support the future identification of innovative therapeutic approaches for these challenging diseases.

Green tea polyphenols protect PC12 cells against H2O2-induced damages by upregulating lncRNA MALAT1

It is of significance to alleviate oxidative damages for the treatment of spinal cord injury (SCI). Studies have ascertained that green tea polyphenols (GTPs) exert protective activities against oxidative damages. In this study, we aimed to investigate the protective effects of GTP against H₂O₂-caused injuries in PC12 cells as well as the molecular underpinnings associated with long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1). PC12 cells were preincubated with GTP prior to H₂O₂ stimulation. Furthermore, MALAT1-deficient PC12 cells were constructed by transfection and identified by quantitative real-time polymerase chain reaction (qRT-PCR) assay. Next, viability and apoptosis were detected by cell counting kit-8 and flow cytometry, respectively. Meanwhile, Western blot assay was carried out to monitor the expression alteration of proteins associated with apoptosis (Bcl-2, Bax, pro-Caspase-3/9, and cleaved Caspase-3/9) and autophagy (microtubule-associated protein 1 light chain 3 (LC3)-II, LC3-I, Beclin-1, and p62). Moreover, we examined the expression of β-catenin and dissected the phosphorylation of phosphatidylinositol 3′-kinase (PI3K) and protein kinase B (AKT). We found that H₂O₂ decreased the viability of PC12 cells while initiated apoptosis and autophagy processes. GTP-preincubated PC12 cells maintained the viability and resisted the apoptosis and autophagy induced by H₂O₂. Pointedly, GTP-pretreated PC12 cells showed an increase in MALAT1 after H₂O₂ stimulation. Of note, the protective effects of GTP were buffered in MALAT1-deficient cells in response to H₂O₂. The expression of β-catenin and phosphorylation of PI3K and AKT were upregulated by GTP, while MALAT1 knockdown led to opposite results. To sum up, GTP protected PC12 cells from H₂O₂-induced damages by the upregulation of MALAT1. This process might be through activating Wnt/β-catenin and PI3K/AKT signal pathways.

LncRNA NRON promotes the proliferation, metastasis and EMT process in bladder cancer

Background: Bladder cancer (BC) is one of the most common malignancies world-wide with high morbidity and mortality. Long noncoding RNAs (lncRNAs) are thought to play a critical role in cancer development. LncRNA NRON, a repressor of activated T-cell nuclear factor (NFAT), has been shown to be dysregulated in many cancer types. However, the clinical significance and molecular mechanism of NRON in bladder cancer is still unknown.

Methods: The expression levels of NRON in BC tissues and cell lines were tested by RT-qPCR. Survival analysis was performed to detect the correlation between NRON expression and clinical outcomes in patients with BC. The biological role of NRON in BC cells proliferation and metastasis was examined in vitro and in vivo.

Results: The expression of NRON was significantly upregulated in BC specimens and cell lines compared with paired adjacent normal tissues and normal cell lines. The upregulation of NRON in bladder cancer patients was significantly associated with the depth of bladder tumor invasion and poor prognosis. Knockdown of NRON inhibited BC cells proliferation, migration, invasion and tumorigenicity. Furthermore, NRON promoted epithelial-mesenchymal transition (EMT) progression, and NRON-induced EZH2 expression contributed to this process.

Conclusion: In conclusion, our results suggested that NRON acted as an oncogene and tumor biomarker for BC.

MALAT1 knockdown inhibits prostate cancer progression by regulating miR-140/BIRC6 axis

BACKGROUND

Prostate cancer (PCa) is the second most common cancer among men globally. Long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been reported to be implicated in tumorigenesis and progression of PCa. However, the pathogenesis of MALAT1 in PCa has not been thoroughly elaborated.

METHODS

RT-qPCR assay was conducted to measure expression of MALAT1, microRNA-140 (miR-140) and Baculoviral IAP repeat containing 6 (BIRC6) mRNA. Protein expression of BIRC6 was detected by western blot assay. Cell proliferative ability was assessed by MTS and Edu retention assays. Cell migratory and invasive abilities were evaluated by wound healing assay and Transwell invasion assay, respectively. Cell apoptotic rate was examined using a flow cytometry. The interaction between miR-140 and MALAT1 or BIRC6 3'UTR was explored by luciferase, RNA immunoprecipitation (RIP) and RNA pull down assays. Xenograft models of PCa were established to further explore the role and molecular mechanism of MALAT in PCa tumorigenesis in vivo.

RESULTS

MALAT1 and BIRC6 were highly expressed in human PCa tumor tissues and cell lines. MALAT1 or BIRC6 knockdown inhibited cell proliferation, migration and invasion and induced cell apoptosis in PCa. MiR-140 could directly bind with MALAT1 or BIRC6 3'UTR. Moreover, MALAT1 knockdown inhibited BIRC mRNA and protein expression through upregulating miR-140 in PCa cells. Additionally, MALAT1 knockdown inhibited PCa xenograft tumor growth by regulating miR-140/BIRC6 axis in vivo.

CONCLUSION

MALAT1 knockdown hindered PCa progression by regulating miR-140/BIRC6 axis in vitro and in vivo, hinting the potential value of MALAT1 in the management of PCa.

Circulating Expression Level of LncRNA Malat1 in Diabetic Kidney Disease Patients and Its Clinical Significance

BACKGROUND

Long noncoding RNA MALAT1 is closely related to diabetes and kidney diseases and is expected to be a new target for the diagnosis and treatment of diabetic nephropathy.

OBJECTIVE

This study aimed to explore the circulating expression level and significance of lncRNA Malat1 in patients with type 2 diabetes mellitus (T2DM) and diabetic kidney disease (DKD).

METHODS

Quantitative real-time PCR (qPCR) was conducted to assess the expression of lncRNA Malat1 in 20 T2DM patients, 27 DKD patients, and 14 healthy controls, and then, the clinical significance was analyzed.

RESULTS

LncRNA MALAT1 expression in peripheral blood mononuclear cells (PBMC) was significantly upregulated in T2DM and DKD groups when compared to control. Pearson's correlation analysis showed correlation of lncRNA MALAT1 levels with ACR, urine β2-microglobulin (β2-MG), urine α1-microglobulin (α1-MG), creatinine (Cr), and glycosylated hemoglobin (HbA1c), while negative with superoxide dismutase (SOD) (r = -0.388, P < 0.05). Binary regression analysis showed that ACR, creatinine, α1-MG, and LncRNA Malat1 were the risk factors for diabetic nephropathy with OR value of 1.166, 1.031, 1.031, and 2.019 (P < 0.05). The area under ROC curve (AUC) of DKD identified by the above indicators was 0.914, 0.643, 0.807, and 0.797, respectively. The AUC of Joint prediction probability of DKD recognition was 0.914, and the sensitivity and specificity of DKD diagnosis were 1.0 and 0.806, respectively. (Take ≥0.251 as the diagnostic cutoff point).

CONCLUSION

LncRNA Malat1 is highly expressed in DKD patients, and the combined detection of ACR, creatinine, α1-MG, and LncRNA Malat1 with diabetes mellitus may be the best way to diagnose diabetic nephropathy.

LncRNA-miRNA interaction prediction through sequence-derived linear neighborhood propagation method with information combination

BACKGROUND

Researchers discover lncRNAs can act as decoys or sponges to regulate the behavior of miRNAs. Identification of lncRNA-miRNA interactions helps to understand the functions of lncRNAs, especially their roles in complicated diseases. Computational methods can save time and reduce cost in identifying lncRNA-miRNA interactions, but there have been only a few computational methods.

RESULTS

In this paper, we propose a sequence-derived linear neighborhood propagation method (SLNPM) to predict lncRNA-miRNA interactions. First, we calculate the integrated lncRNA-lncRNA similarity and the integrated miRNA-miRNA similarity by combining known lncRNA-miRNA interactions, lncRNA sequences and miRNA sequences. We consider two similarity calculation strategies respectively, namely similarity-based information combination (SC) and interaction profile-based information combination (PC). Second, the integrated lncRNA similarity-based graph and the integrated miRNA similarity-based graph are respectively constructed, and the label propagation processes are implemented on two graphs to score lncRNA-miRNA pairs. Finally, the weighted averages of their outputs are adopted as final predictions. Therefore, we construct two editions of SLNPM: sequence-derived linear neighborhood propagation method based on similarity information combination (SLNPM-SC) and sequence-derived linear neighborhood propagation method based on interaction profile information combination (SLNPM-PC). The experimental results show that SLNPM-SC and SLNPM-PC predict lncRNA-miRNA interactions with higher accuracy compared with other state-of-the-art methods. The case studies demonstrate that SLNPM-SC and SLNPM-PC help to find novel lncRNA-miRNA interactions for given lncRNAs or miRNAs.

CONCLUSION

The study reveals that known interactions bring the most important information for lncRNA-miRNA interaction prediction, and sequences of lncRNAs (miRNAs) also provide useful information. In conclusion, SLNPM-SC and SLNPM-PC are promising for lncRNA-miRNA interaction prediction.

MALAT1: a therapeutic candidate for a broad spectrum of vascular and cardiorenal complications

Cardiovascular and renal complications cover a wide array of diseases. The most commonly known overlapping complications include cardiac and renal fibrosis, cardiomyopathy, cardiac hypertrophy, hypertension, and cardiorenal failure. The known or reported causes for the abovementioned complications include injury, ischemia, infection, and metabolic stress. To date, various targets have been reported and investigated in detail that are considered to be the cause of these complications. In the past 5 years, the role of noncoding RNAs has emerged in the area of cardiovascular and renal research, especially in relation to metabolic stress. The long noncoding RNA MALAT1 (metastasis-associated lung adenocarcinoma transcript 1) has shown immense promise among the long noncoding RNA targets for treating cardiorenal complications. In this review, we shed light on the role of MALAT1 as a primary and novel target in treating cardiovascular and renal diseases as a whole.

LncRNAs in ocular neovascularizations

The prevalence of eye diseases worldwide is dramatically increasing and represents a major concern in underdeveloped and developed regions. Ocular diseases, previously associated with a higher depression risk, also impose a substantial economic burden on affected families, thus early detection and/or accurate treatment in order to avoid and prevent blindness should be emphasized. Ocular neovascularization (NV), the leading cause of blindness in a variety of eye diseases, is a pathologic process characterized by the formation, proliferation and infiltration of anomalous, tiny and leaky fragile blood vessels within the eye. Genetics have been suspected to play an important role in the occurrence of eye diseases, with the detection of a numbers of specific gene mutations. Long non-coding RNA (lncRNAs) are novel class of regulatory molecules previously associated with various biological processes and diseases, however the nature of the relation and pathways by which they might contribute to the development of corneal, choroidal and retinal NV have not yet been completely elucidated. In this review, we focus on the regulation and characteristics of lncRNAs, summarize results from ocular NV-related studies and discuss the implication of lncRNAs in ocular NV development.

Knockdown of lncRNA TDRG1 Inhibits Tumorigenesis in Endometrial Carcinoma Through the PI3K/AKT/mTOR Pathway

BACKGROUND AND OBJECTIVE

Endometrial carcinoma (EC) is one of the most frequently diagnosed malignancies in females. Dysregulation of lncRNA TDRG1 has been widely documented in several cancers, including EC. However, the mechanism of this lncRNA involving in EC progression remains to be further elucidated.

MATERIALS AND METHODS

The enrichment levels of TDRG1 in EC tissues and cell lines were examined by RT-qPCR. Flow cytometry, cell counting kit-8 (CCK-8), transwell, and Western blot assays were conducted to assess whether TDRG1 knockdown could affect cell cycle arrest, proliferation, migration, invasion, and apoptosis of EC cells. The phosphorylation levels of mTOR, AKT and PI3K that associated with PI3K/Akt/mTOR pathway were determined by Western blot assay.

RESULTS

TDRG1 expression was markedly upregulated in EC tissues and cell lines. Knockdown of TDRG1 significantly induced cell cycle arrest and apoptosis, inhibited cell proliferation, restrained the invasion and migration abilities in EC cells. Moreover, TDRG1 silencing decreased the protein levels of p-AKT, p-PI3K, and p-mTOR of EC cells.

CONCLUSION

Our data underlined the implication of TDRG1 in EC progression, proposing that targeting TDRG1 might be a potential therapeutic avenue in EC.

Long non-coding RNA NEAT1 can predict various malignant tumour lympha node metastasis: a meta-analysis

It has been found in several studies and research that the long non-coding RNA (Inc RNA) NEAT1 plays an important role in the development and succession in various malignant tumour. The development and metastasis of tumour mainly happen through lymph node. The purpose of this research is to explore the value of lymph node metastasis (LNM) in cancer. We have collected all the concerned studies about NEAT1 and researched the relationship between NEAT1 and lymph node metastasis. We have searched the studies by seeking database PubMed, Web of Science, and China National Knowledge Infrastructure (up to 10 January 2019), as well as a total of 821 patients from eight studies topics and made accordingly meta-analysis. By analyzing the data, we have found that the result is the high expression of NEAT1 associate with the metastasis of lymph node in different malignant tumours. The high level of NEAT1 expression can predict the metastasis of lymph node (OR = 3.36, 95% CI = 1.66-6.77, p = .000) and it is a molecular marker of positive lymph node for treatment.

Silencing long noncoding RNA OGFRP1 inhibits the proliferation and migration of cervical carcinoma cells

Cervical cancer is still a serious threat to women's health and life safety worldwide, and new treatment strategies are urgently needed. Accumulating evidences also imply that long non-coding RNAs (lncRNAs) are involved in a wide range of cellular processes, such as cell proliferation, apoptosis, and cell cycle. We found that the expression of lncOGFRP1 in cervical cancer tissues was significantly higher than that in normal cervical tissues (P < .05). Further, CCK8 detection found when lncOGFRP1 was silenced, the proliferation of cells was inhibited. After depleting lncOGFRP1, the proportion of apoptosis cells in C33A (3.71 ± 0.38% VS 11.98 ± 1.26%, P < .05) and SiHa (0.69 ± 0.06% VS 11.06 ± 1.03%, P < .05) cells increased significantly, and cell cycle was arrested in S phase. On the other hand, migration detection found the migration of cells also was hindered when lncOGFRP1 level was reduced. And the depletion of lncOGFRP1 inhibited the expression of β-catenin, Vimentin, N-cadherin, and SNAIL and promoted the expression of E-cadherin. In summary, we first discovered the high expression of lncOGFRP1 in cervical cancer and revealed that silencing lncOGFRP1 inhibits the proliferation and migration of cervical carcinoma cells. SIGNIFICANCE OF THE STUDY: We first discovered the high expression of lncOGFRP1 in cervical cancer and revealed that silencing lncOGFRP1 inhibits the proliferation and migration of cervical carcinoma cells. These results help to better understand the pathogenesis and development of cervical cancer and provide insight to develop better diagnosis and treatment strategies.

Long noncoding RNA LCAT1 functions as a ceRNA to regulate RAC1 function by sponging miR-4715-5p in lung cancer

Introduction

Long noncoding RNAs (lncRNAs) are emerging as key players in the development and progression of cancer. However, the biological role and clinical significance of most lncRNAs in lung carcinogenesis remain unclear. In this study, we identified and explored the role of a novel lncRNA, lung cancer associated transcript 1 (LCAT1), in lung cancer.

Methods

We predicted and validated LCAT1 from RNA-sequencing (RNA-seq) data of lung cancer tissues. The LCAT1–miR-4715-5p–RAC1 axis was assessed by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. Signaling pathways altered by LCAT1 knockdown were identified using RNA-seq. Furthermore, the mechanism of LCAT1 was investigated using loss-of-function and gain-of-function assays in vivo and in vitro.

Results

LCAT1 is an oncogene that is significantly upregulated in lung cancer tissues and associated with poor prognosis. LCAT1 knockdown caused growth arrest and cell invasion in lung cancer cells in vitro, and inhibited tumorigenesis and metastasis in the mouse xenografts. Mechanistically, LCAT1 functions as a competing endogenous RNA for miR-4715-5p, thereby leading to the upregulation of the activity of its endogenous target, Rac family small GTPase 1 (RAC1). Moreover, EHop-016, a small molecule inhibitor of RAC1, as an adjuvant could improve the Taxol monotherapy against lung cancer cells in vitro.

Conclusions

LCAT1–miR-4715-5p–RAC1/PAK1 axis plays an important role in the progression of lung cancer. Our findings may provide valuable drug targets for treating lung cancer. The novel combination therapy of Taxol and EHop-016 for lung cancer warrants further investigation, especially in lung cancer patients with high LCAT1 expression.

Long noncoding RNA MEG3 suppresses podocyte injury in diabetic nephropathy by inactivating Wnt/β-catenin signaling

Background

Diabetic nephropathy (DN) is one of the principal complications of diabetes and podocyte injury plays an important role in the DN pathogenesis. Wnt/β-catenin signaling overactivation confers podocyte injury and promotes multiple types of renal disease. However, the underlying mechanism of Wnt/β-catenin signaling activation in DN progression has not been fully elucidated. Long noncoding RNA (lncRNA) is a large class of endogenous RNA molecules lacking functional code capacity and which participates in the pathogenesis of human disease, including DN.

Method

A diabetes model was constructed by intraperitoneal injection of Streptozotocin in rats. The MPC5 cells were used to create the in vitro model. Western blot and Quantitative reverse-transcriptase-PCR were used to examine the expression of protein and mRNA. The migrated capacity was analyzed by Transwell migration assay. The cell viability was detected by CCK8.

Results

In the present study, we revealed the association of lncRNA Maternally Expressed Gene 3 (MEG3) with aberrant activation of Wnt/β-catenin signaling and the role of MEG3/Wnt axis in podocyte injury. We found that high glucose (HG) treatment suppressed MEG3 expression in cultured podocytes, activated Wnt/β-catenin signaling and caused podocyte injury as indicated by the downregulation of podocyte-specific markers (podocin and synaptopodin) and the upregulation of snail1 and α-smooth muscle actin. Overexpression of MEG3 attenuated HG-induced podocyte injury by reducing Wnt/β-catenin activity, repressing cell migration, reactive oxygen species production and increasing the viability of podocytes. Furthermore, we provided evidences that restoration of Wnt/β-catenin signaling by specific agonist impeded the protective effect of MEG3 on podocyte injury. Current results demonstrated that MEG3/Wnt axis plays an important role in fostering podocyte injury and may serve as a potential therapeutic target for the treatment of DN.

Conclusion

lncRNA MEG3 ameliorates podocyte injury in DN via inactivating Wnt/β-catenin signaling.

Regulation of mTOR signaling by long non-coding RNA

The mechanistic target of rapamycin (mTOR) is a major signaling hub that coordinates cellular and organismal responses, such as cell growth, proliferation, apoptosis, and metabolism. Dysregulation of mTOR signaling occurs in many human diseases, and there are significant ongoing efforts to pharmacologically target this pathway. Long noncoding RNAs (lncRNA), defined by a length > 200 nucleotides and absence of a long open-reading-frame, are a class of non-protein-coding RNAs. Mutations and dysregulations of lncRNAs are directly linked to the development and progression of many diseases, including cancer, diabetes, and neurologic disorders. Recent findings reveal diverse functions for lncRNA that include transcriptional regulation, organization of nuclear domains, and regulation of proteins or RNA molecules. Despite considerable development in our understanding of lncRNA over the past decade, only a fraction of annotated lncRNAs has been examined for biological function. In addition, lncRNAs have emerged as therapeutic targets due to their ability to modulate multiple pathways, including mTOR signaling. This review will provide an up-to-date summary of lncRNAs that are involved in regulating mTOR pathway.

LncRNA DLEU2 accelerates the tumorigenesis and invasion of non-small cell lung cancer by sponging miR-30a-5p

Long non‐coding RNAs (lncRNAs) have been reported to participate in the pathogenesis of non–small cell lung cancer (NSCLC). However, how lncRNA deleted in lymphocytic leukaemia 2 (DLEU2) contributes to NSCLC remains undocumented. The clinical significance of lncRNA DLEU2 and miR‐30a‐5p expression in NSCLC was analysed by using fluorescence in situ hybridization and TCGA cohorts. Gain‐ and loss‐of‐function experiments as well as a NSCLC tumour model were executed to determine the role of lncRNA DLEU2 in NSCLC. DLEU2‐sponged miR‐30a‐5p was verified by luciferase reporter, and RIP assays. Herein, the expression of lncRNA DLEU2 was elevated in NSCLC tissues, and its high expression or low expression of miR‐30a‐5p acted as an independent prognostic factor of poor survival and tumour recurrence in NSCLC. Silencing of lncRNA DLEU2 repressed the tumorigenesis and invasive potential of NSCLC, whereas re‐expression of lncRNA DLEU2 showed the opposite effects. Furthermore, lncRNA DLEU2 harboured a negative correlation with miR‐30a‐5p expression in NSCLC tissues and acted as a sponge of miR‐30a‐5p, which reversed the tumour‐promoting effects of lncRNA DLEU2 by targeting putative homeodomain transcription factor 2 in NSCLC. Altogether, lncRNA DLEU2 promoted the tumorigenesis and invasion of NSCLC by sponging miR‐30a‐5p.

Identification of a four-long non-coding RNA signature in predicting breast cancer survival

Long non-coding RNAs (lncRNAs) serve key roles in tumorigenesis and are differentially expressed in cancer. Using bioinformatics and statistical methods, the present study aimed to identify an lncRNA signature to predict breast cancer survival. The gene expression data of 768 patients with breast cancer were downloaded from The Cancer Genome Atlas database, and Cox regression, Kaplan-Meier and receiver operating characteristic (ROC) analyses were performed to construct and validate a predictive model. Gene Ontology term enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analysis were employed to predict the functions of the indicated lncRNAs. A signature consisting of four lncRNAs, including PVT1, MAPT-AS1, LINC00667 and LINC00938, was identified, and patients were subsequently divided into high- and low-risk groups according to the median risk score. Kaplan-Meier analysis confirmed that patients in the high-risk group exhibited significantly poorer overall survival rate in both the training (P=0.0151) and the validation set (P=0.0016); furthermore, ROC analysis confirmed that the model could predict patient survival with a certain sensitivity and specificity. In conclusion, the four-lncRNA signature presents a potential prognostic biomarker for breast cancer that may be relevant for clinical application.

lncRNA MALAT1 Accelerates Skeletal Muscle Cell Apoptosis and Inflammatory Response in Sepsis by Decreasing BRCA1 Expression by Recruiting EZH2

Sepsis is a serious and elusive syndrome caused by infection, which is accompanied by a high mortality worldwide. Recent evidence has documented the regulatory role of long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) during the inflammatory process, the effects of which in the development of sepsis have become the focus of the current study. An in vivo mouse model and in vitro cell model of sepsis induced by lipopolysaccharide (LPS) were developed. High expression of lncRNA MALAT1 along with low expression of breast cancer susceptibility gene 1 (BRCA1) were identified in septic mice and human skeletal muscle cells of sepsis. Then, lncRNA MALAT1 expression was altered in vivo and in vitro to examine serum levels of inflammatory factors, as well as skeletal muscle cell apoptosis. lncRNA MALAT1 was noted to regulate the expression and export from the nucleus of BRCA1 by recruiting zeste homolog 2 (EZH2) in skeletal muscle cells of sepsis. Silencing lncRNA MALAT1 resulted in reduced serum levels of interleukin (IL)-6, IL-8, and tumor necrosis factor alpha (TNF-α), neutrophil migration, skeletal muscle cell apoptosis, and AKT-1 phosphorylation. Taken together, lncRNA MALAT1 interacting with EZH2 stimulated AKT-1 phosphorylation and decreased BRCA1 expression, consequently aggravating the progression of sepsis, highlighting a promising therapeutic option for sepsis.

Prenatal maternal biomarkers for the early diagnosis of congenital malformations: A review

Congenital anomalies cause ~7% of all neonatal deaths, many of which have no identified pathophysiological cause. Because accurate and robust laboratory tests are unavailable for most birth defects, physicians rely on imaging such as ultrasound and MRI. Biomarkers from human body fluids are considered a powerful diagnostic tool to assess human disease and health as it mirrors an individual's condition. Minimally invasive 'liquid biopsies' from blood samples are highly valuable for diagnosis, prognosis, risk assessment, and treatment of many conditions. Recent large-scale analysis ('omics') have enabled researchers to identify novel biomarkers in different areas. To accurately facilitate the early detection of congenital anomalies, the identification of biomarkers from maternal plasma should be promoted. This approach will uncover new opportunities in prenatal diagnosing and likely lead to a better understanding of the pathogenesis of congenital anomalies.

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.

LncRNA MALAT1 shuttled by bone marrow-derived mesenchymal stem cells-secreted exosomes alleviates osteoporosis through mediating microRNA-34c/SATB2 axis

Long non-coding RNAs (lncRNAs) have emerged as promising novel modulators during osteogenesis in mesenchymal stem cells (MSCs). Enhanced SATB2 has been demonstrated to promote osteogenic differentiation of bone marrow-derived mesenchymal stem cells (hBMSCs) in patients with osteonecrosis. Preliminary bioinformatic analysis identified putative binding sites between microRNA-34c (miR-34c) and metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) or miR-34c and SATB2 3'UTR. Thus, the current study aimed to clarify the potential functional relevance of MALAT1-containing exosomes from BMSCs in osteoporosis. The extracted exosomes from primary BMSCs were co-cultured with human osteoblasts (hFOB1.19), followed by evaluation of the hFOB1.19 cell proliferation, alkaline phosphatase (ALP) activity and mineralized nodules. The obtained findings indicated that BMSC-Exos promoted the expression of SATB2 in osteoblasts, and SATB2 silencing reduced the ALP activity of osteoblasts and mineralized nodules. MALAT1 acted as a sponge of miR-34c to promote the expression of SATB2. Additionally, BMSCs-derived exosomal MALAT1 promoted osteoblast activity. Moreover, in vivo experiments indicated that miR-34c reversed the effect of MALAT1, and SATB2 reversed the effect of miR-34c in ovariectomized mice. Taken together, this study demonstrates that BMSCs-derived exosomal MALAT1 enhances osteoblast activity in osteoporotic mice by mediating the miR-34c/SATB2 axis.

Upregulation of LncRNA Malat1 Induced Proliferation and Migration of Airway Smooth Muscle Cells via miR-150-eIF4E/Akt Signaling

The increased proliferation and migration of airway smooth muscle cells (ASMCs) are critical processes in the formation of airway remodeling in asthma. Long non-coding RNAs (lncRNAs) have emerged as key mediators of diverse physiological and pathological processes, and are involved in the pathogenesis of various diseases, including asthma. LncRNA Malat1 has been widely reported to regulate the proliferation and migration of multiple cell types and be involved in the pathogenesis of various human diseases. However, it remains unknown whether Malat1 regulates ASMC proliferation and migration. Here, we explored the function of Malat1 in ASMC proliferation and migration in vitro stimulated by platelet-derived growth factor BB (PDGF-BB), and the underlying molecular mechanism involved. The results showed that Malat1 was significantly upregulated in ASMCs treated with PDGF-BB, and knockdown of Malat1 effectively inhibited ASMC proliferation and migration induced by PDGF-BB. Our data also showed that miR-150 was a target of Malat1 in ASMCs, and inhibited PDGF-BB-induced ASMC proliferation and migration, whereas the inhibition effect was effectively reversed by Malat1 overexpression. Additionally, translation initiation factor 4E (eIF4E), an important regulator of Akt signaling, was identified to be a target of miR-150, and both eIF4E knockdown and Akt inhibitor GSK690693 inhibited PDGF-BB-induced ASMC proliferation and migration. Collectively, these data indicate that Malat1, as a competing endogenous RNA (ceRNA) for miR-150, derepresses eIF4E expression and activates Akt signaling, thereby being involved in PDGF-BB-induced ASMC proliferation and migration. These findings suggest that Malat1 knockdown may present a new target to limit airway remodeling in asthma.

Long non-coding RNAs and nuclear factor-κB crosstalk in cancer and other human diseases

The regulation of the pleiotropic transcription factor, nuclear factor-κB (NF-κB) by miRNAs and proteins is extensively studied. More recently, the NF-κB signaling was also reported to be regulated by several long non-coding RNAs (lncRNAs) that constitute the major portion of the noncoding component of the human genome. The common NF-κB associated lncRNAs include NKILA, HOTAIR, MALAT1, ANRIL, Lethe, MIR31HG, and PACER. The lncRNA and NF-κB signaling crosstalk during cancer and other diseases such as cardiomyopathy, celiac disease, cerebral infarction, chronic kidney disease, diabetes mellitus, Kawasaki disease, pregnancy loss, and rheumatoid arthritis. Some NF-κB related lncRNAs can affect gene expression without modulating NF-κB signaling. Most of the lncRNAs with a potential to modulate NF-κB signaling are regulated by NF-κB itself suggesting a feedback regulation. The discovery of lncRNAs have provided a new type of regulation for the NF-κB signaling and thus could be explored for therapeutic interventions. The manner in which lncRNA and NF-κB crosstalk affects human pathophysiology is discussed in this review. The challenges associated with the therapeutic interventions of this crosstalk are also discussed.

Identification of novel LncRNA targeting Smad2/PKCα signal pathway to negatively regulate malignant progression of glioblastoma

Glioblastoma multiforme (GBM) is a highly proliferative cancer with generally poor prognosis and accumulating evidence has highlighted the potential of long noncoding RNAs (lncRNAs) in the biological behaviors of glioma cells. This study focused on the identification of lncRNAs to identify targets for possible GBM prognosis. Microarray expression profiling found that 1,759 lncRNAs and 3,026 messenger RNAs (mRNAs) were upregulated, and 1932s lncRNA and 2,979 mRNAs were downregulated in GBM. Bioinformatics analysis and experimental verification identified TCONS_00020456 (TCON) for further analysis. In situ hybridization, along with immunohistochemical and receiver operating characteristic analysis determined TCON (truncation value = 3.5) as highly sensitive and specific in GBM. Grade IV patients with glioma life span with different lncRNA staining scores were analyzed. TCON staining scores below 3.5 indicated poor prognosis (life span ranging from 0.25 to 7 months), even if the glioma was surgically removed. TCON decreased significantly in GBM, and showed a coexpressional relationship with Smad2 and protein kinase C α (PKCα). Overexpression of TCON reduced the proliferation on one hand and migration, invasion on the other. TCON also inhibited epithelial–mesenchymal transformation and glioma progression in vivo, based on a nude mouse tumorigenicity assay. In addition, we predicted a potential binding site and intersection that microRNAs targeting Smad2, PKCα, and TCON through RACE pretest and bioinformatics analysis. Taken together, TCON, regarded as oncosuppressor, targeting the Smad2/PKCα axis plays a novel role in inhibiting the malignant progression of glioma. Moreover, it also demonstrates that the level of TCON can be used as a prognostic and diagnostic biomarker for GBM.

Long noncoding RNA MALAT1 releases epigenetic silencing of HIV-1 replication by displacing the polycomb repressive complex 2 from binding to the LTR promoter

Long noncoding RNAs (lncRNAs) may either repress or activate HIV-1 replication and latency; however, specific mechanisms for their action are not always clear. In HIV-1 infected CD4⁺ T cells, we performed RNA-Sequencing (RNA-Seq) analysis and discovered an up-regulation of MALAT1 (metastasis-associated lung adenocarcinoma transcript 1), an lncRNA previously described in cancer cells that associate with cancer pathogenesis. Moreover, we found that MALAT1 promoted HIV-1 transcription and infection, as its knockdown by CRISPR/Cas9 markedly reduced the HIV-1 long terminal repeat (LTR)-driven gene transcription and viral replication. Mechanistically, through an association with chromatin modulator polycomb repressive complex 2 (PRC2), MALAT1 detached the core component enhancer of zeste homolog 2 (EZH2) from binding with HIV-1 LTR promoter, and thus removed PRC2 complex-mediated methylation of histone H3 on lysine 27 (H3K27me3) and relieved epigenetic silencing of HIV-1 transcription. Moreover, the reactivation of HIV-1 stimulated with latency reversal agents (LRAs) induced MALAT1 expression in latently infected cells. Successful combination antiretroviral therapy (cART) was accompanied by significantly diminished MALAT1 expression in patients, suggesting a positive correlation of MALAT1 expression with HIV-1 replication. Our data have identified MALAT1 as a promoter of HIV-1 transcription, and suggested that MALAT1 may be targeted for the development of new therapeutics.

Long noncoding RNAs and exosomal lncRNAs: classification, and mechanisms in breast cancer metastasis and drug resistance

Breast cancer is the most common cancer, and the second cause of cancer-related deaths (after lung cancer) among women. Developing tumor metastasis and invasion is the most important cause of death in breast cancer patients. Several key factors participate in breast cancer metastasis including long noncoding RNAs (lncRNAs). lncRNAs are a category of cellular RNAs that are longer than 200 nucleotides in length. Accumulating evidence suggests that lncRNAs have the potential to be promising diagnostic, prognostic biomarkers and therapeutic targets in breast cancer. Understanding the role of lncRNAs and their mechanisms of functions might help to further discovery of breast cancer biological characteristics. In this review, we discuss physiological functions, epigenetic regulation, transcriptional regulation of lncRNAs, and their important role in tumor progression and metastasis. Some lncRNAs function as oncogenes and some function as tumor suppressors. Interestingly, recent reports depict that hypomethylation of promoters of lncRNAs play a pivotal role in cancer progression, suggesting the importance of epigenetic regulation. Furthermore, we discuss the role of lncRNAs in exosomes and their function in drug resistance, and therapeutic importance of exosomal lncRNAs in cancer biology. In summary, lncRNAs have a great potential to consider them as novel prognostic biomarkers as well as new therapeutic targets in breast cancer.

Resveratrol attenuates pulmonary embolism associated cardiac injury by suppressing activation of the inflammasome via the MALAT1‑miR‑22‑3p signaling pathway

Resveratrol (RS) has been reported to prevent the development of cardiac injury induced by pulmonary embolism (PE). The present study aimed to explore the potential mechanism of RS involved in cardiac injury induced by PE. A luciferase assay was conducted to detect the effect of RS on promoter efficiency of metastasis associated lung adenocarcinoma transcript 1 (MALAT1), in‑silico analysis and luciferase assays were performed to explore the regulatory relationship between MALAT1, microRNA (miR)‑22‑3p and NLRP3. Reverse transcription PCR, western blot analysis and ELISA were carried out to examine MALAT1, miR‑22‑3p, NLRP3, ASC, Caspase‑1, interleukin (IL)‑1β and IL‑18 among different animal model groups, including the sham group, PE associated cardiac injury group and PE associated cardiac injury plus RS group. The results revealed that RS downregulated promoter efficiency of MALAT1 and MALAT1 directly targeted miR‑22‑3p, and luciferase activity of MALAT1 was inhibited by miR‑22‑3p, and furthermore miR‑22‑3p inhibited the expression of NLRP3 by binding to complementary sequences in the 3' untranslated region of NLRP3. MALAT1, NLRP3, ASC, Caspase‑1, IL‑1β and IL‑18 levels were much increased, while miR‑22‑3p level was much decreased in PE associated cardiac injury group compared with the sham group, while the RS upon the PE associated cardiac injury group slightly reduced the upregulated MALAT1/NLRP3 level and elevated the downregulated miR‑22‑3p level. In conclusion, it was demonstrated that RS has been demonstrated to prevent the development of cardiac injury induced by PE via modulating the expression of MALAT1 and further affect miR‑22‑3p and NLRP3.

Endothelial function and dysfunction in the cardiovascular system: the long non-coding road

Present throughout the vasculature, endothelial cells (ECs) are essential for blood vessel function and play a central role in the pathogenesis of diverse cardiovascular diseases. Understanding the intricate molecular determinants governing endothelial function and dysfunction is essential to develop novel clinical breakthroughs and improve knowledge. An increasing body of evidence demonstrates that long non-coding RNAs (lncRNAs) are active regulators of the endothelial transcriptome and function, providing emerging insights into core questions surrounding EC contributions to pathology, and perhaps the emergence of novel therapeutic opportunities. In this review, we discuss this class of non-coding transcripts and their role in endothelial biology during cardiovascular development, homeostasis, and disease, highlighting challenges during discovery and characterization and how these have been overcome to date. We further discuss the translational therapeutic implications and the challenges within the field, highlighting lncRNA that support endothelial phenotypes prevalent in cardiovascular disease.

MALAT1-KTN1-EGFR regulatory axis promotes the development of cutaneous squamous cell carcinoma

Long noncoding RNAs (LncRNAs), including MALAT1, are critical regulators of tumor development. However, the roles and molecular mechanisms of LncRNAs in cutaneous squamous cell carcinoma (cSCC) remain underexplored. In this study, functional studies using in vitro cellular and in vivo xenograft models confirmed the pro-carcinogenic roles of MALAT1 in cSCC. Further, MALAT1 was identified to regulate epidermal growth factor receptor (EGFR) protein expression but did not affect EGFR mRNA expression. Transcriptomic sequencing identified kinectin 1 (KTN1) as the key mediator for MALAT1 regulation of EGFR. Mechanistic study revealed that MALAT1 interacts with c-MYC to form a complex and directly binds to the promoter region of KTN1 gene and enhances its transactivation to positively regulate EGFR protein expression. Our findings, therefore, establish a novel c-MYC-assisted MALAT1-KTN1-EGFR axis, which contributes to cSCC development and may serve as novel target for therapeutic intervention.

Suppression of MALAT1 ameliorates chronic constriction injury-induced neuropathic pain in rats via modulating miR-206 and ZEB2

Long noncoding RNAs (lncRNAs) are involved in multiple nervous system diseases, including neuropathic pain. Previous studies have demonstrated that lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been identified as a diagnostic biomarker in many diseases. Nevertheless, the function of MALAT1 in neuropathic pain progression is still unclear. Here, we established a chronic constriction injury (CCI) rat model. We found that MALAT1 was remarkably upregulated in CCI rats. In addition, neuropathic pain behaviors such as mechanical and thermal hyperalgesia were reduced by the inhibition of MALAT1. Meanwhile, the loss of MALAT1 was able to depress the neuroinflammation process via the inhibition of COX-2, interleukin-1β, and interleukin-6. A previous study has indicated that miR-206 upregulation can restrain the CCI-induced neuropathic pain. Furthermore, we exhibited that miR-206 was significantly downregulated and silence of MALAT1 restrained its expression in CCI rats. For another, ZEB2 was a target of miR-206 and it was shown that ZEB2 was elevated in CCI rats in a time-dependent manner. Overexpression of miR-206 obviously suppressed ZEB2 levels in rat microglial cells. Subsequently, it was demonstrated that upregulation of miR-206 rescued the neuropathic pain triggered by ZEB2 overexpression in vivo through neuroinflammation inhibition. Overall, we indicated that suppression of MALAT1 ameliorated neuropathic pain progression via miR-206/ZEB2 axis.

Association of long non-coding RNA HOTAIR and MALAT1 variants with cervical cancer risk in Han Chinese women

Long noncoding RNA (lncRNA) HOTAIR and MALAT1 are implicated in the development of multiple cancers. Genetic variants within HOTAIR and MALAT1 may affect the gene expression, thereby modifying genetic susceptibility to cervical cancer. A case-control study was designed, including 1 486 cervical cancer patients and 1 536 healthy controls. Based on RegulomeDB database, 11 SNPs were selected and genotyped by using Sequenom's Mass ARRAY. Univariate and multivariate logistic regression models were used to calculate the odds ratio (OR) and 95% confidence interval (CI). We found that the A allele of rs35643724 in HOTAIR was associated with increased risk of cervical cancer, while the C allele of rs1787666 in MALAT1 was associated with decreased risk. Compared to individuals with 0–1 unfavorable allele, those with 3–4 unfavorable alleles showed 18% increased odds of having cervical cancer. Our findings suggest that HOTAIR rs35643724 and MALAT1 rs1787666 might represent potential biomarkers for cervical cancer susceptibility.

miR-124-3p availability is antagonized by LncRNA-MALAT1 for Slug-induced tumor metastasis in hepatocellular carcinoma

BACKGROUND

As an oncogene, long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) can promote tumor metastasis. Hyperexpression of MALAT1 has been observed in many malignant tumors, including hepatocellular carcinoma (HCC). However, the role and mechanism of MALAT1 in HCC remain unclear.

METHODS

Thirty human HCC and paracancerous tissue specimens were collected, and the human hepatoma cell lines Huh7 and HepG2 were cultured according to standard methods. MALAT1 and Snail family zinc finger (Slug) expression were measured by real-time PCR, immunohistochemistry, and western blotting. Luciferase reporter assay and RNA immunoprecipitation (RIP) assay verified the direct interaction between miR-124-3p and Slug(SNAI2) or MALAT1. Wound healing and transwell assays were performed to examine invasion and migration, and a subcutaneous tumor model was established to measure tumor progression in vivo.

RESULTS

MALAT1 expression was upregulated in HCC tissues and positively correlated with Slug expression. MALAT1 and miR-124-3p bind directly and reversibly to each other. MALAT1 silencing inhibited cell migration and invasion. miR-124-3p inhibited HCC metastasis by targeting Slug.

CONCLUSIONS

MALAT1 regulates Slug through miR-124-3p, affecting HCC cell metastasis. Thus, the MALAT1/miR-124-3p/Slug axis plays an important role in HCC.

The long noncoding RNA MIR210HG promotes tumor metastasis by acting as a ceRNA of miR-1226-3p to regulate mucin-1c expression in invasive breast cancer

Background: Long noncoding RNAs have been known to be involved in multiple types of malignancies, including invasive breast cancer (IBC). This study aimed to explore the role of long noncoding RNAs in IBC and elucidate the potential molecular mechanisms.

Methods: Using TCGA microarray data analysis, we identified a long noncoding RNA, MIR210HG, highly expressed in IBC. Kaplan-Meier method and the log-rank test were used for survival analysis. The gain-of-function experiments were performed to assess the function of MIR210HG in IBC invasion and migration in both in vitro and in vivo settings. Bioinformatic analysis as well as luciferase reporter assay, rescue experiments and western blot assay revealed the mode of action of MIR210HG.

Results: The aberrantly enhanced MiR210HG expression predicted poor prognosis and lower survival rate. Knockdown of MiR210HG suppressed IBC cell invasion and metastasis both in vitro and in vivo. MiR-1226-3p was identified and validated to be the target miRNA of MiR210HG. Furthermore, MiR210HG functions as a competing endogenous RNAs (ceRNA) which sponges miR-1226-3p, therefore upregulates the expression of mucin1 (MUC1-C).

Conclusions: Our study demonstrated that MiR210HG sponges miR-1226-3p to facilitate invasive breast cancer cell invasion and metastasis by regulating mucin-1c and EMT pathway, revealing the oncogenic role of MiR210HG in IBC cells.

An antisense transcript mediates MALAT1 response in human breast cancer

BACKGROUND

Long non-coding RNAs (lncRNAs) represent a substantial portion of the human transcriptome. LncRNAs present a very stringent cell-type/tissue specificity being potential candidates for therapeutical applications during aging and disease. As example, targeting of MALAT1, a highly conserved lncRNA originally identified in metastatic non-small cell lung cancer, has shown promising results in cancer regression. Nevertheless, the regulation and specificity of MALAT1 have not been directly addressed. Interestingly, MALAT1 locus is spanned by an antisense transcript named TALAM1.

METHODS

Here using a collection of breast cancer cells and in vitro and in vivo migration assays we characterized the dynamics of expression and demonstrated that TALAM1 regulates and synergizes with MALAT1 during tumorigenesis.

RESULTS

Down-regulation of TALAM1 was shown to greatly impact on the capacity of breast cancer cells to migrate in vitro or to populate the lungs of immunocompromised mice. Additionally, we demonstrated that TALAM1 cooperates with MALAT1 in the regulation of the properties guiding breast cancer aggressiveness and malignancy.

CONCLUSIONS

By characterizing this sense/anti-sense pair we uncovered the complexity of MALAT1 locus regulation, describing new potential candidates for cancer targeting.

Inhibition of long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 attenuates high glucose-induced cardiomyocyte apoptosis via regulation of miR-181a-5p

Diabetic cardiomyopathy (DCM) is one of the cardiovascular complications of diabetes mellitus independent of hypertension, coronary disease, and other heart diseases. The development of DCM is multifactorial and hard to detect at an early stage. Long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (Malat1) is emerging as a regulator of DCM, the underlying mechanism of its role in DCM has not been elaborated yet. In this study, we established a mouse DCM model via streptozocin injection as evidenced by cell hypertrophy and cell apoptosis of myocardial tissue, and found that Malat1 expression was upregulated in the myocardium in DCM mice. Meanwhile, elevated expression of pro-apoptotic factors p53, p21, cleaved caspase 3, cleaved caspase 9 and BAX, and down-regulation of anti-apoptotic BCL-2 were observed in DCM myocardium. We further investigated the effect of Malat1 on cardiomyocytes under high glucose condition by silencing Malat1 with its specific short-hairpin RNA. Like in vivo, expression of Malat1 in cardiomyocytes was notably raised, remarkable cell apoptosis and changes in apoptosis-related factors were also observed following high glucose treatment. Besides, we validated that Malat1 acted as a sponge of miR-181a-5p. Inhibition of miR-181a-5p could, at least partially, abolish Malat1 knockdown-induced alteration in cardiomyocytes. In addition, p53, a critical regulator of apoptosis, was validated to be a downstream target of miR-181a-5p. In summary, our findings reveal that Malat1 knockdown attenuates high glucose-induced cardiomyocyte apoptosis via releasing miR-181a-5p, and this mechanism may provide us with new diagnosis target of DCM.

Long non-coding RNA Malat1 activated autophagy, hence promoting cell proliferation and inhibiting apoptosis by sponging miR-101 in colorectal cancer

Background

Long non-coding RNA Malat1 has been widely identified as an oncogene which shows a significant relationship with tumorigenesis in colorectal cancer (CRC). Nonetheless, whether Malat1 participates in the autophagy of colorectal cancer remains unclear.

Materials and methods

First, the expression level of Malat1 in 96 pairs of colorectal cancer tissues and four cell lines was detected by qRT-PCR. Subsequently, the autophagy activity in colorectal cancer tissues and cell lines was detected by western blot. Furthermore, the CCK-8 assay and flow cytometry (FCM) were performed to detect the role of autophagy activated by Malat1 in colorectal cancer cell lines.

Results

In this study, significantly increased Malat1 expression and autophagy activity were found in colorectal cancer tissues compared with the adjacent normal tissues. Also, the Malat1 level was positively correlated with the expression of LC3-II mRNA in vivo. Moreover, autophagy activation and cell proliferation were significantly facilitated by Malat1 in colorectal cancer cells, while apoptosis decreased. Above all, the inhibition of autophagy by 3-MA not only relieved the Malat1-induced cell proliferation but also promoted the Malat1-induced cell apoptosis. In addition, Malat1 was found to act as an endogenous sponge by directly binding to miR-101 to reduce miR-101. Furthermore, the suppressive effects of miR-101 on the autophagy, proliferation, and apoptosis of CRC were abolished by Malat1.

Conclusion

Long non-coding RNA Malat1 activated autophagy and promoted cell proliferation, yet inhibited apoptosis by sponging miR-101 in colorectal cancer cells.

Long non-coding RNA LINC00858 promotes cells proliferation, migration and invasion by acting as a ceRNA of miR-22-3p in colorectal cancer

Though long non-coding RNA LINC00858 (LINC00858) has been shown to be involved in tumours of other tissues, its involvement in colorectal cancer (CRC) is still unknown. We aimed to investigated expression and mechanism LINC00858 in human CRC. In this study, we firstly found that LINC00858 expression was significantly up-regulated in both CRC tissues and cell lines by both online data and RT-PCR assay. Then, clinical assay revealed that high LINC00858 expression was significantly associated with advanced clinical progression and poor prognosis. Multivariate analysis demonstrated that high LINC00858 expression was an independent poor prognostic factor for CRC patients. Moreover, lost-of-function assay indicated that knockdown of LINC00858 suppressed CRC cells proliferation, migration and invasion, and promoted apoptosis. Mechanistically, bioinformatics analysis, dual-luciferase reporter assays, and western blot assays showed that LINC00858 functioned as competing endogenous RNA to repress miR-22-3p, which controlled its down-stream target YWHAZ. Then, we suggested that LINC00858 exerted its function through the miR-22-3p/YWHAZ axis. To our knowledge, this is the first report which showed the role of LINC00858 in the progression of CRC. Our findings indicated that LINC00858 played an important role in CRC, and may serve as a novel prognostic factor and therapeutic target.

Crosstalk between the lncRNA UCA1 and microRNAs in cancer

Long non-coding RNAs (lncRNAs) are a major subset of highly conserved non-coding RNAs (ncRNAs) that consist of at least 200 nucleotides and have limited protein-coding potential. Cumulative data have shown that lncRNAs are deregulated in many types of cancer and may control pathophysiological processes of cancer at various levels, including transcription, post-transcription and translation. Recently, lncRNAs have been demonstrated to interact with microRNAs (miRNAs), another major subset of ncRNAs, which regulate physiological and pathological processes by inhibiting target mRNA translation or promoting mRNA degradation. The lncRNA urothelial carcinoma-associated 1 (UCA1) has recently gained much attention as it is overexpressed in many types of cancer and is involved in carcinogenesis. Here, we review the crosstalk between UCA1 and miRNAs during the pathogenesis of cancer, with a focus on cancer-cell proliferation, invasion, drug resistance, and metabolism.

Identification of prognostic signatures associated with long-term overall survival of thyroid cancer patients based on a competing endogenous RNA network

Competing endogenous RNAs (ceRNAs) are considered as transcripts that can regulate each other at post-transcription level by competing for shared miRNAs. Considering the key roles of lncRNAs acting as ceRNAs in progression of solid tumors, to develop prognostic signatures in thyroid cancer (THCA), patients with corresponding clinical data were selected and two ceRNA networks were constructed using online databases. Two prognostic signatures (Lnc5m4 and Lnc2mi1m2) were found to be more efficient in predicting long-term survival of THCA patients. However, the high-risk score of Lnc2mi1m2 was not an independent factor.The risk score of Lnc5m4 was able to effectively stratify patients in stage III-IV into low- and high-risk groups, and also could predict poor prognosis of patients in stage III-IV. In conclusion, these findings indicate that Lnc5m4 is a novel prognostic signature for predicting long-term overall survival of THCA patients, which could provide a new approach to lncRNA research in THCA progression.

Targeted nanocomplex carrying siRNA against MALAT1 sensitizes glioblastoma to temozolomide

Intrinsic therapeutic resistance especially in cancer stem cells (CSCs) together with extensive tumor cell infiltration and restricted permeation of the blood-brain barrier (BBB) by drugs may all contribute to the treatment failure in patients with glioblastoma multiforme (GBM). Accumulating evidence suggests that long non-coding RNA (lncRNA), metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) plays a role in tumor cell infiltration and therapeutic resistance of GBM. Using our tumor-targeted nanocomplex, we have modulated the expression of MALAT1 and investigated its impact on GBM cells. Importantly, our nanocomplex is able to target CSCs that are considered to be the prime culprits in therapeutic resistance and recurrence of GBM. Attenuation of MALAT1 by RNA interference significantly lowered the growth, motility and stemness of GBM cells. In addition, silencing of MALAT1 clearly improved the sensitivity of GBM cells to chemotherapeutic agents including the current first-line therapy of GBM [temozolomide (TMZ)]. In animal models of GBM, tumor involution with a modest but statistically significant survival benefit was achieved with concurrent treatment of TMZ and nanocomplex-mediated silencing of MALAT1. These results suggest that combining standard TMZ treatment with lncRNA-targeting therapies using our nanocomplex could substantially enhance the very poor prognosis for GBM patients.

MALAT1-Driven Inhibition of Wnt Signal Impedes Proliferation and Inflammation in Fibroblast-Like Synoviocytes Through CTNNB1 Promoter Methylation in Rheumatoid Arthritis

Fibroblast-like synoviocytes (FLSs) participate in the pathogenesis of rheumatoid arthritis (RA). Emerging evidence has highlighted the role of long non-coding RNA metastasis associated lung adenocarcinoma transcript 1 (MALAT1) and its potential involvement in RA. In this study, we test the hypothesis that the MALAT1 might inhibit proliferation and inflammatory response of FLSs in RA. The expression of MALAT1 was examined in synovial tissues from patients with RA. The effect of MALAT1 on cultured FLSs was analyzed by introducing overexpressed MALAT1 or short hairpin RNA (shRNA) against MALAT1. To validate whether methylation of CTNNB1 promoter was affected by MALAT1 alternation, we assessed the recruitment of DNA methyltransferases to CTNNB1 promoter. In cultured FLSs with shRNA-mediated CTNNB1 knockdown or activated Wnt signaling, we found the interaction between CTNNB1 and Wnt signaling. MALAT1 expression was reduced in synovial tissues of RA. MALAT1 could bind to CTNNB1 promoter region and recruit methyltransferase to promote CTNNB1 promoter methylation, thereby inhibiting CTNNB1. Notably, MALAT1 could suppress the transcription and expression of CTNNB1, thereby modulating the Wnt signaling pathway. Silenced MALAT1 stimulated the nucleation of β-catenin and the secretion of inflammatory cytokines including interleukin-6, interleukin-10, and tumor necrosis factor-α. Additionally, shRNA-mediated MALAT1 silencing elevated proliferation and suppressed apoptosis of FLSs accompanied. These findings provide evidence for the inhibitory effect of MALAT1 on proliferation and inflammation of FLSs by promoting CTNNB1 promoter methylation and inhibiting the Wnt signaling pathway. Therefore, this study provides a candidate therapeutic target for RA.

Global Positioning System: Understanding Long Noncoding RNAs through Subcellular Localization

The localization of long noncoding RNAs (lncRNAs) within the cell is the primary determinant of their molecular functions. LncRNAs are often thought of as chromatin-restricted regulators of gene transcription and chromatin structure. However, a rich population of cytoplasmic lncRNAs has come to light, with diverse roles including translational regulation, signaling, and respiration. RNA maps of increasing resolution and scope are revealing a subcellular world of highly specific localization patterns and hint at sequence-based address codes specifying lncRNA fates. We propose a new framework for analyzing sequencing-based data, which suggests that numbers of cytoplasmic lncRNA molecules rival those in the nucleus. New techniques promise to create high-resolution, transcriptome-wide maps associated with all organelles of the mammalian cell. Given its intimate link to molecular roles, subcellular localization provides a means of unlocking the mystery of lncRNA functions.

LncRNA MALAT1 is involved in sevoflurane-induced neurotoxicity in developing rats

OBJECTIVE

The purpose of this study is to uncover the effects of long chain noncoding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) on sevoflurane-induced neurotoxicity in developing rats.

METHODS

Sevoflurane neurotoxicity model was established by sevoflurane treatment in 7-day-old Sprague-Dawley rats. The rats were treated with Sevo or MALAT1 small interfering RNA to detect the MALAT1 expression, pathological change, ultrastructure, neuronal apoptosis, expression of apoptosis-related proteins, expression of neurotrophic factors BDNF and NGF, spatial learning and memory function change, as well as neuron cell density of hippocampal tissues.

RESULTS

MALAT1 was highly expressed in hippocampus tissues of rats. Downregulation of MALAT1 alleviated the pathological change, improved the ultrastructure, inhibited apoptosis of neuronal cells, declined caspase 3 and Bax while elevated Bcl-2, BDNF and NGF, improved capability of spatial learning and memory, and increased density of hippocampal neurons in hippocampal tissues of sevoflurane-induced rats.

CONCLUSION

Suppression of MALAT1 can reduce the apoptosis of hippocampal neurons induced by sevoflurane anesthesia, improve the capability of spatial learning, and memory function and alleviate the loss of hippocampal nerve cells in developing rats. To a certain extent, it plays the role of protecting brain nerve cells.

The functional roles of exosomal long non-coding RNAs in cancer

Exosomes are extracellular membranous vesicles that are secreted by various cell types. Exosomes have become indispensable facilitators in the exchange of information between cells. More importantly, exosomes perform a crucial role in a variety of diseases including cancers. Long non-coding RNAs (lncRNAs) are over 200 nucleotides long transcripts that exhibit no or limited protein-coding potentials. LncRNAs are an emerging group of regulatory RNAs and can be selectively packaged into exosomes. Exosomal lncRNAs play a central role in carcinogenesis and cancer progression by modulating tumor growth, metastasis, angiogenesis and chemoresistance. Moreover, exosomal lncRNAs function as messengers in cell-to-cell communication, and thus remodel the tumor microenvironment. Their function relevance in cancer biology hints at the possibility of employing exosomal lncRNAs as promising, non-invasive biomarkers for further cancer therapy. In this review, we provide an overview of current research on the functional roles of exosomal lncRNAs in cancer and discuss their potential clinical applications as diagnostic biomarkers and therapeutic targets for cancers.

LncRNAs and epigenetic regulation of vascular endothelium: genome positioning system and regulators of chromatin modifiers

Epigenetic mechanisms regulate the cell type-specific expression of endothelial-enriched genes. A major question has been how chromatin modifiers without inherent sequence specificity can be targeted to genomic coordinates. Recently, long noncoding RNAs (lncRNAs) have emerged as candidates for specifying genomic positioning for chromatin modifiers. However, lncRNAs function by a number of mechanisms in both the nucleus and the cytoplasm. Recent studies indicate the existence of endothelial-enriched lncRNAs. This review discusses lncRNA regulation in endothelial cells with a focus on four recently described nuclear-enriched lncRNAs: MANTIS, LEENE, STEEL, and GATA6-AS. This emerging work on these lncRNAs contributes to our understanding of epigenetic regulation in the vascular endothelium with links to important themes in endothelial biology, including angiogenesis and shear stress.

MALAT1 regulates the transcriptional and translational levels of proto-oncogene RUNX2 in colorectal cancer metastasis

Ectopic expression of lncRNA-MALAT1 has been discovered in recurrent colorectal cancer (CRC) and metastatic sites in postsurgical patients, however, its biological mechanism remained unelucidated. Our study first revealed the novel roles of MALAT1 in promoting CRC metastasis through two mechanisms: first, MALAT1 binds miR-15 family members, to "de-inhibit" their effect on LRP6 expression, enhances β-catenin signaling, leading to elevated transcriptional levels of downstream target genes RUNX2. Second, MALAT1 binds SFPQ, and dissociates SFPQ/PTBP2 dimer to release free PTBP2, which elevates translational levels of RUNX2, through interacting with IRES domain in the 5'UTR of the corresponding RUNX2 mRNAs. Moreover, increased RUNX2 expression levels were detected in recurrent CRC tumors, which were closely associated with TMN stages, metastasis, as well as CRC patients' survival. Our study demonstrated that MALAT1 and RUNX2 may serve as two biomarkers for predicting the recurrence and metastasis of CRC patients.

Long Noncoding RNA MALAT1 Regulates Cancer Glucose Metabolism by Enhancing mTOR-Mediated Translation of TCF7L2

Reprogrammed glucose metabolism of enhanced aerobic glycolysis (or the Warburg effect) is known as a hallmark of cancer. The roles of long noncoding RNAs (lncRNA) in regulating cancer metabolism at the level of both glycolysis and gluconeogenesis are mostly unknown. We previously showed that lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) acts as a proto-oncogene in hepatocellular carcinoma (HCC). Here, we investigated the role of MALAT1 in regulating cancer glucose metabolism. MALAT1 upregulated the expression of glycolytic genes and downregulated gluconeogenic enzymes by enhancing the translation of the metabolic transcription factor TCF7L2. MALAT1-enhanced TCF7L2 translation was mediated by upregulation of SRSF1 and activation of the mTORC1-4EBP1 axis. Pharmacological or genetic inhibition of mTOR and Raptor or expression of a hypophosphorylated mutant version of eIF4E-binding protein (4EBP1) resulted in decreased expression of TCF7L2. MALAT1 expression regulated TCF7L2 mRNA association with heavy polysomes, probably through the TCF7L2 5'-untranslated region (UTR), as determined by polysome fractionation and 5'UTR-reporter assays. Knockdown of TCF7L2 in MALAT1-overexpressing cells and HCC cell lines affected their metabolism and abolished their tumorigenic potential, suggesting that the effects of MALAT1 on glucose metabolism are essential for its oncogenic activity. Taken together, our findings suggest that MALAT1 contributes to HCC development and tumor progression by reprogramming tumor glucose metabolism. SIGNIFICANCE: These findings show that lncRNA MALAT1 contributes to HCC development by regulating cancer glucose metabolism, enhancing glycolysis, and inhibiting gluconeogenesis via elevated translation of the transcription factor TCF7L2.

Emerging Roles of p53 Related lncRNAs in Cancer Progression: A Systematic Review

p53 is the major mediator of the tumor suppressor response. It participates in apoptosis and senescence and can respond to DNA damage. As a crucial sequence-specific transcription factor, p53 regulates the expression of many genes, such as small noncoding RNAs (ncRNAs), microRNAs, and long ncRNAs (lncRNAs). Given the emergence of novel and high-throughput sequencing technologies, many lncRNAs have been discovered. LncRNAs may function as vital gene regulators in a variety of biological processes through extensive mechanisms. Recently, lncRNAs have been demonstrated to be associated with the p53 regulatory pathway. In this review, we discuss the current and fast growing knowledge about the influence of lncRNAs to the p53 signaling pathway, the different mechanisms by which they affect gene expression in cancer. Our findings show that p53-associated lncRNAs may be used as biomarkers for cancer diagnosis or targets for disease therapy.