LncRNA HOTAIR: A master regulator of chromatin dynamics and cancer. Biochim Biophys Acta Rev Cancer. 2015;1856:151-164. [PMID: 26208723 DOI: 10.1016/j.bbcan.2015.07.001]

Identification and Validation of a Novel Immune-Related lncRNA Signature for Bladder Cancer

Purpose

We aimed to construct an immune-related long noncoding ribonucleic acids (irlncRNA) signature to evaluate the prognosis of patients without specific expression level of these irlncRNA.

Methods

The raw transcriptome data were downloaded from The Cancer Genome Atlas (TCGA), irlncRNAs were filtered out using an online immune related gene database and coexpression analysis, differently expressed irlncRNA (DEirlncRNA) pairs were identified by univariate analysis. The areas under curve (AUC) were compared and the Akaike information criterion (AIC) values of receiver operating curve (ROC) was counted, the most optimal model was constructed to divide bladder cancer patients into high- and low-risk groups usingõ the cut-off point of ROC. Then, we evaluated them from multiple perspectives, such as survival time, clinic-pathological characteristics, immune-related cells infiltrating, chemotherapeutics efficacy and immune checkpoint inhibitors.

Results

14 DEirlncRNA pairs were included in this signature. Patients in high-risk groups demonstrated apparent shorter survival time, more aggressive clinic-pathological characteristics, different immune-related cells infiltrating status, lower chemotherapeutics efficacy.

Conclusion

The irlncRNA signature demonstrated a promising prediction value for bladder cancer patients and was important in guiding clinical treatment.

Long noncoding RNA uc003pxg.1 regulates endothelial cell proliferation and migration via miR‑25‑5p in coronary artery disease

Long noncoding RNAs (lncRNAs) have been reported to be associated with the progression of coronary artery disease (CAD). In our previous study, the levels of lncRNA uc003pxg.1 were upregulated in patients with CAD compared with those in control subjects. However, the role and underlying mechanism of the effects of uc003pxg.1 in CAD remain unknown. Therefore, the aim of the present study was to investigate the expression pattern and biological function of uc003pxg.1 in CAD. First, uc003pxg.1 expression levels were assessed in peripheral blood mononuclear cells isolated from patients with CAD by reverse transcription‑quantitative (RT‑q)PCR. The results demonstrated that the levels of uc003pxg.1 were significantly upregulated (~4.6‑fold) in samples from 80 patients with CAD compared with those in 80 healthy subjects. Subsequently, the present study demonstrated that small interfering RNA‑mediated uc003pxg.1 knockdown inhibited human umbilical vein endothelial cell (HUVEC) proliferation and migration, which was analyzed using the Cell Counting Kit‑8, cell cycle, EdU and Transwell assays. Additionally, the results of RT‑qPCR and western blot analyses revealed that uc003pxg.1 regulated the mRNA and protein levels of cyclin D1 and cyclin‑dependent kinase. Through high‑throughput sequencing and dual‑luciferase reporter assays, the present study demonstrated that microRNA (miR)‑25‑5p was a downstream target of uc003pxg.1. Further experiments verified that uc003pxg.1 regulated HUVEC proliferation and migration via miR‑25‑5p. The results of the present study may enhance the current understanding of the role of lncRNA uc003pxg.1 in CAD.

Individualized lncRNA differential expression profile reveals heterogeneity of breast cancer

Long non-coding RNAs (lncRNAs) play key regulatory roles in breast cancer. However, population-level differential expression analysis methods disregard the heterogeneous expression of lncRNAs in individual patients. Therefore, we individualized lncRNA expression profiles for breast invasive carcinoma (BRCA) using the method of LncRNA Individualization (LncRIndiv). After evaluating the robustness of LncRIndiv, we constructed an individualized differentially expressed lncRNA (IDElncRNA) profile for BRCA and investigated the subtype-specific IDElncRNAs. The breast cancer subtype-specific IDElncRNA showed frequent co-occurrence with alterations of protein-coding genes, including mutations, copy number variation and differential methylation. We performed hierarchical clustering to subdivide TNBC and revealed mesenchymal subtype and immune subtype for TNBC. The TNBC immune subtype showed a better prognosis than the TNBC mesenchymal subtype. LncRNA PTOV1-AS1 was the top differentially expressed lncRNA in the mesenchymal subtype. And biological experiments validated that the upregulation of PTOV1-AS1 could downregulate TJP1 (ZO-1) and E-Cadherin, and upregulate Vimentin, which suggests PTOV1-AS1 may promote epithelial-mesenchymal transition and lead to migration and invasion of TNBC cells. The mesenchymal subtype showed a higher fraction of M2 macrophages, whereas the immune subtype was more associated with CD4 + T cells. The immune subtype is characterized by genomic instability and upregulation of immune checkpoint genes, thereby suggesting a potential response to immunosuppressive drugs. Last, drug response analysis revealed lncRNA ENSG00000230082 (PRRT3-AS1) is a potential resistance biomarker for paclitaxel in BRCA treatment. Our analysis highlights that IDElncRNAs can characterize inter-tumor heterogeneity in BRCA and the new TNBC subtypes indicate novel insights into TNBC immunotherapy.

Aberrant Expression of Long Non Coding RNA HOTAIR and De-Regulation of the Paralogous 13 HOX Genes Are Strongly Associated with Aggressive Behavior of Gastro-Entero-Pancreatic Neuroendocrine Tumors

Gastro-entero-pancreatic neuroendocrine neoplasms (GEP-NENs) are rare diseases occurring in the gastrointestinal tract and pancreas. They are characterized by the loss of epithelial tubular gland elements, and by the increased expression of neuroendocrine markers. GEP-NENs are subdivided into two histo-pathological types, gastro-entero-pancreatic neuroendocrine tumors (GEP-NETs) and gastro-entero-pancreatic neuroendocrine carcinomas (GEP-NECs). According to WHO 2017 and 2019 classification criteria are graded and staged in four categories, NET-G1, NET-G2, NET-G3, and NEC-G3. The molecular characterization of these tumors can be fundamental for the identification of new diagnostic, prognostic and predictive biomarkers. The main purpose of this study was to analyze the expression of the paralogous 13 HOX genes, normally involved in embryogenic development and frequently deregulated in human cancers, and of the HOX regulating lncRNA HOTAIR in GEP-NENs. The expression of HOX genes is gradually lost in the transition from GEP NET G1 to NET/NEC G3 tumors, while HOTAIR expression, inversely correlated with HOX genes expression and weakly expressed in low-grade GEP NENs, becomes aberrant in NET G3 and NEC G3 categories. Our data highlights their potential role in the molecular stratification of GEP-NENs by suggesting new prognostic markers and potential therapeutic targets.

Long non-coding RNAs and their involvement in bipolar disorders

Non-coding RNAs (nc-RNAs) can be defined as RNA molecules that are not translated into proteins. Although the functional meaning of many nc-RNAs remains still to be verified, several of these molecules have a clear biological importance, which goes from translation of mRNAs to DNA replication. Indeed, regulatory nc-RNAs can be classified into two groups: short non-coding RNAs (sncRNAs) and long-non coding RNAs (lncRNAs). In the last years, lncRNAs have gained increasing importance in the study of gene regulation, helping authors understand the molecular mechanisms underlying cellular physiology and pathology. LncRNAs are greater than 200 bp and accumulate in nucleus, cytoplasm and exosomes with high tissue specificity, acting in cis or in trans in order to exert enhancer or silencer modulation on gene expression. Such regulatory features, which are widespread in human cells and tissues, can be disrupted in several morbid states. Recent evidences may suggest a disruption of lncRNAs in bipolar disorders, a cluster of severe, chronic and disabling psychiatric diseases, which are characterized by major depressive states cyclically alternating with manic episodes. Here, the authors reviewed genes, classification, biogenesis, structures, functions and databases regarding lncRNAs, and also focused on bipolar disorders, in which some lncRNAs, especially those involved in inflammation and neuronal development, has reported to be dysregulated.

lncRNA MALAT1 participates in metformin inhibiting the proliferation of breast cancer cell

In recent years, the repurposing of conventional and chemotherapeutic drugs is recognized as an alternative strategy for health care. The main purpose of this study is to strengthen the application of non‐oncological drug metformin on breast cancer treatment in the perspective of epigenetics. In the present study, metformin was found to inhibit cell proliferation, promote apoptosis and induce cell cycle arrest in breast cancer cells at a dose‐dependent manner. In addition, metformin treatment elevated acH3K9 abundance and decreased acH3K18 level. The expression of lncRNA MALAT1, HOTAIR, DICER1‐AS1, LINC01121 and TUG1 was up‐regulated by metformin treatment. In metformin‐treated cells, MALAT1 knock‐down increased the Bax/Bcl2 ratio and enhanced p21 but decreased cyclin B1 expression. The expression of Beclin1, VDAC1, LC3‐II, CHOP and Bip was promoted in the cells received combinatorial treatment of metformin and MALAT1 knock‐down. The reduced phosphorylation of c‐Myc was further decreased in the metformin‐treated cells in combination with MALAT1 knock‐down than metformin treatment alone. Taken together, these results provide a promising repurposed strategy for metformin on cancer treatment by modulating epigenetic modifiers.

Long Non-Coding RNA Epigenetics

Long noncoding RNAs exceeding a length of 200 nucleotides play an important role in ensuring cell functions and proper organism development by interacting with cellular compounds such as miRNA, mRNA, DNA and proteins. However, there is an additional level of lncRNA regulation, called lncRNA epigenetics, in gene expression control. In this review, we describe the most common modified nucleosides found in lncRNA, 6-methyladenosine, 5-methylcytidine, pseudouridine and inosine. The biosynthetic pathways of these nucleosides modified by the writer, eraser and reader enzymes are important to understanding these processes. The characteristics of the individual methylases, pseudouridine synthases and adenine-inosine editing enzymes and the methods of lncRNA epigenetics for the detection of modified nucleosides, as well as the advantages and disadvantages of these methods, are discussed in detail. The final sections are devoted to the role of modifications in the most abundant lncRNAs and their functions in pathogenic processes.

Deciphering the Long Non-Coding RNAs and MicroRNAs Coregulation Networks in Ovarian Cancer Development: An Overview

Non-coding RNAs are emergent elements from the genome, which do not encode for proteins but have relevant cellular functions impacting almost all the physiological processes occurring in eukaryotic cells. In particular, microRNAs and long non-coding RNAs (lncRNAs) are a new class of small RNAs transcribed from the genome, which modulate the expression of specific genes at transcriptional and posttranscriptional levels, thus adding a new regulatory layer in the flux of genetic information. In cancer cells, the miRNAs and lncRNAs interactions with its target genes and functional pathways are deregulated as a consequence of epigenetic and genetic alterations occurring during tumorigenesis. In this review, we summarize the actual knowledge on the interplay of lncRNAs with its cognate miRNAs and mRNAs pairs, which interact in coregulatory networks with a particular emphasis on the mechanisms underlying its oncogenic behavior in ovarian cancer. Specifically, we reviewed here the evidences unraveling the relevant roles of lncRNAs/miRNAs pairs in altered regulation of cell migration, angiogenesis, therapy resistance, and Warburg effect. Finally, we also discussed its potential clinical implications in ovarian cancer and related endocrine disease therapies.

The molecular basis of mammary gland development and epithelial differentiation

Our understanding of the molecular events underpinning the development of mammalian organ systems has been increasing rapidly in recent years. With the advent of new and improved next-generation sequencing methods, we are now able to dig deeper than ever before into the genomic and epigenomic events that play critical roles in determining the fates of stem and progenitor cells during the development of an embryo into an adult. In this review, we detail and discuss the genes and pathways that are involved in mammary gland development, from embryogenesis, through maturation into an adult gland, to the role of pregnancy signals in directing the terminal maturation of the mammary gland into a milk producing organ that can nurture the offspring. We also provide an overview of the latest research in the single-cell genomics of mammary gland development, which may help us to understand the lineage commitment of mammary stem cells (MaSCs) into luminal or basal epithelial cells that constitute the mammary gland. Finally, we summarize the use of 3D organoid cultures as a model system to study the molecular events during mammary gland development. Our increased investigation of the molecular requirements for normal mammary gland development will advance the discovery of targets to predict breast cancer risk and the development of new breast cancer therapies.

Association between HOTAIR lncRNA Polymorphisms and Coronary Artery Disease Susceptibility

Coronary artery disease (CAD), one of the most frequent causes of mortality, is the most common type of cardiovascular disease. This condition is characterized by the accumulation of plaques in the coronary artery, leading to blockage of blood flow to the heart. The main symptom of CAD is chest pain caused by blockage of the coronary artery and shortness of breath. HOX transcript antisense RNA gene (HOTAIR) is a long non-coding RNA which is well-known as an oncogene involved in various cancers, such as lung, breast, colorectal, and gastric cancer. We selected six single nucleotide polymorphisms, rs4759314 A>G, rs1899663 G>T, rs920778 T>C, rs7958904 G>C, rs12826786 C>T, and rs874945 C>T, for genotype frequency analysis and assessed the frequency of HOTAIR gene polymorphisms in 442 CAD patients and 418 randomly selected control subjects. To analyze the differences between these two populations, we performed a Student's t-test, adjusted odds ratio (AOR), 95% confidence intervals (CIs), and ANOVA analysis. According to our baseline characteristic analysis, control subjects and CAD patients were significantly different in hypertension and diabetes mellitus. We also found that the rs4759314 A>G, rs1899663 G>T, and rs12826786 C>T genotypes were strongly associated with CAD susceptibility (AA vs. AG+GG: AOR = 0.608, 95% CI = 0.393-0.940, p = 0.025; GG vs. TT: AOR = 2.276, 95% CI = 1.125-4.607, p = 0.022; CC vs. CT+TT: AOR = 1.366, 95% CI = 1.027-1.818, p = 0.032, respectively). Our data also demonstrated that the genotype of HOTAIR polymorphisms, genotype combination, and haplotype analysis affect disease occurrence. Moreover, these polymorphisms are linked to clinical factors that contribute to disease susceptibility. In conclusion, results from our study suggest that HOTAIR polymorphisms may be useful novel biomarkers for diagnosing CAD.

The prognostic impact of abnormally expressed, long noncoding RNAs in acute myeloid leukemia: a meta-analysis

Objectives: A growing number of studies demonstrate that long noncoding RNAs (lncRNAs) could act as biomarkers to determine the prognosis of acute myeloid leukemia (AML) patients. Nonetheless, the significance of lncRNAs in AML prognosis remains unclear. We conducted a meta-analysis to assess the prognostic indicators of abnormally expressed lncRNAs in AML. Methods: Literature was searched using PubMed, EMBASE, and Web of Science databases up to November 10, 2018. Results: Thirteen studies with 2755 individuals were included. The abnormal expression of lncRNAs was associated with worse overall survival (OS) in AML patients, especially in cytogenetically normal AML (CN-AML), and was associated with shorter disease-free survival and event-free survival. Subgroup analysis showed that high levels of HOTAIR and TUG1 were associated with poor OS. Discussion: Overexpression of lncRNA HOTAIR and TUG1 were reported in two separate studies, and correlated with worse AML prognoses. Conclusion: Abnormally expressed lncRNAs are significantly related to worse prognoses of AML patients and might serve as potential prognostic markers to predict the prognosis of AML patients.

lncRNA APOC1P1-3 promoting anoikis-resistance of breast cancer cells

BACKGROUND

Anoikis resistance plays a critical role in the tumor metastasis by allowing survival of cancer cells in the systemic circulation. We previously showed that long non-coding RNAs APOC1P1-3 (lncRNA APOC1P1-3) inhibit apoptosis of breast cancer cells. In this study, we explored its role in anoikis resistance.

METHODS

We induced anoikis resistance in two breast cancer cell lines (MCF-7 and MDA-MB-231) under anchorage-independent culture conditions and studied lncRNA APOC1P1-3 effects on apoptosis. Using Dual-Luciferase activity assay, we determined whether it specifically binds to miRNA-188-3P. We further explored its role in lung metastasis by injecting MDA-MB-231 and MDA-MB-231-APOC1P1-3-knock-down cells in female BALB/c nude mice.

RESULTS

We found that lncRNA APOC1P1-3 suppressed early apoptosis of these cells (demonstrated by gain or loss of their function, respectively) and promoted anoikis resistance via reducing activated- Caspase 3, 8, 9 and PARP. Moreover, it specifically binds to the target miRNA-188-3p acting as a "sponge" to block the inhibition of Bcl-2 (an anti-apoptosis protein).

CONCLUSIONS

Our study supports a theory that lncRNA APOC1P1-3 can promote development of breast cancer metastasis via anoikis resistance by specifically binding to miRNA-188-3p to block the inhibition of Bcl-2.

The Role of lncRNAs in the Pathobiology and Clinical Behavior of Multiple Myeloma

Simple Summary

Multiple myeloma (MM), the second most common hematological neoplasm, is still considered an incurable disease. Long non-coding RNAs (lncRNAs), genes that do not encode proteins, participate in numerous biological processes, but their deregulation, like that of coding genes, can contribute to carcinogenesis. Increasing evidence points to the relevant role of lncRNAs in the development of human tumors, such that they emerge as attractive biomarkers and therapeutic targets for cancer treatment, including MM. Here we review the oncogenic or tumor-suppressor functions of lncRNAs in MM and provide an overview of novel therapeutic approaches based on lncRNAs that will help to improve the management of these patients.

Abstract

MM is a hematological neoplasm that is still considered an incurable disease. Besides established genetic alterations, recent studies have shown that MM pathogenesis is also characterized by epigenetic aberrations, such as the gain of de novo active chromatin marks in promoter and enhancer regions and extensive DNA hypomethylation of intergenic regions, highlighting the relevance of these non-coding genomic regions. A recent study described how long non-coding RNAs (lncRNAs) correspond to 82% of the MM transcriptome and an increasing number of studies have demonstrated the importance of deregulation of lncRNAs in MM. In this review we focus on the deregulated lncRNAs in MM, including their biological or functional mechanisms, their role as biomarkers to improve the prognosis and monitoring of MM patients, and their participation in drug resistance. Furthermore, we also discuss the evidence supporting the role of lncRNAs as therapeutic targets through different novel RNA-based strategies.

Fucoidan Inhibits the Progression of Hepatocellular Carcinoma via Causing lncRNA LINC00261 Overexpression

Hepatocellular carcinoma (HCC) as a main type of primary liver cancers has become one of the most deadly tumors because of its high morbidity and poor prognosis. Fucoidan is a family of natural, heparin-like sulfated polysaccharides extracted from brown algae. It is not only a widely used dietary supplement, but also participates in many biological activities, such as anti-oxidation, anti-inflammation and anti-tumor. However, the mechanism of fucoidan induced inhibition of HCC is elusive. In our study, we demonstrated that fucoidan contributes to inhibiting cell proliferation in vivo and in vitro, restraining cell motility and invasion and inducing cell cycle arrest and apoptosis. According to High-Throughput sequencing of long-non-coding RNA (lncRNA) in MHCC-97H cells treated with 0.5 mg/mL fucoidan, we found that 56 and 49 lncRNAs were correspondingly up- and down-regulated. LINC00261, which was related to the progression of tumor, was highly expressed in fucoidan treated MHCC-97H cells. Moreover, knocking down LINC00261 promoted cell proliferation by promoting the expression level of miR-522-3p, which further decreased the expression level of downstream SFRP2. Taken together, our results verified that fucoidan effectively inhibits the progression of HCC via causing lncRNA LINC00261 overexpression.

RNAs as Regulators of Cellular Matchmaking

RNA molecules are increasingly being identified as facilitating or impeding the interaction of proteins and nucleic acids, serving as so-called scaffolds or decoys. Long non-coding RNAs have been commonly implicated in such roles, particularly in the regulation of nuclear processes including chromosome topology, regulation of chromatin state and gene transcription, and assembly of nuclear biomolecular condensates such as paraspeckles. Recently, an increased awareness of cytoplasmic RNA scaffolds and decoys has begun to emerge, including the identification of non-coding regions of mRNAs that can also function in a scaffold-like manner to regulate interactions of nascently translated proteins. Collectively, cytoplasmic RNA scaffolds and decoys are now implicated in processes such as mRNA translation, decay, protein localization, protein degradation and assembly of cytoplasmic biomolecular condensates such as P-bodies. Here, we review examples of RNA scaffolds and decoys in both the nucleus and cytoplasm, illustrating common themes, the suitability of RNA to such roles, and future challenges in identifying and better understanding RNA scaffolding and decoy functions.

Long Noncoding RNA NEAT1: A Potential Biomarker in the Progression of Laryngeal Squamous Cell Carcinoma

INTRODUCTION

Laryngeal squamous cell carcinoma (LSCC) is diverse in its natural history and responsiveness to treatments. There is an urgent need to generate candidate biomarkers for the stratification and individualization of treatment to avoid overtreatment or inadequate treatment. Long noncoding RNA nuclear paraspeckle assembly transcript 1 (NEAT1) has been identified as an oncogenic gene in multiple human tumors entitles, and dysregulation of NEAT1 was tightly linked to carcinogenesis and cancer progression.

METHODS

One hundred two paraffin samples of LSCC patients were collected. Furthermore, in situ hybridization (ISH), Kaplan-Meier, and MTT were used to analyze the relationship between NEAT1 and the progress of LSCC.

RESULTS

In this study, ISH revealed that NEAT1 was strongly expressed in the nucleus. The increased expression of NEAT1 was correlated with T grade, neck nodal metastasis, clinical stage, drinking history, or smoking history of LSCC. The Kaplan-Meier analysis indicated that patients with higher NEAT1 expression had a worse overall survival in LSCC patients. In addition, NEAT1 knockdown significantly inhibited the growth of LSCC cells.

CONCLUSION

Together, these results suggested that NEAT1 involved in the progress of LSCC and might act as a tumor oncogenic gene. This study provides a potential new marker and target for gene therapy in the treatment of LSCC.

An angiogenesis-related long noncoding RNA signature correlates with prognosis in patients with hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent and lethal cancers worldwide. Neovascularization is closely related to the malignancy of tumors. We constructed a signature of angiogenesis-related long noncoding RNA (lncRNA) to predict the prognosis of patients with HCC. The lncRNA expression matrix of 424 HCC patients was downloaded from The Cancer Genome Atlas (TCGA). First, gene set enrichment analysis (GSEA) was used to distinguish the differentially expressed genes of the angiogenesis genes in liver cancer and adjacent tissues. Next, a signature of angiogenesis-related lncRNAs was constructed using univariate and multivariate analyses, and receiver operating characteristic (ROC) curves were used to assess the accuracy. The signature and relevant clinical information were used to construct the nomogram. A 5-lncRNA signature was highly correlated with overall survival (OS) in HCC patients and performed well in evaluations using the C-index, areas under the curve, and calibration curves. In summary, the 5-lncRNA model can serve as an accurate signature to predict the prognosis of patients with liver cancer, but its mechanism of action must be further elucidated by experiments.

LncRNA GAS5 inhibits Invasion and Migration of Lung Cancer through influencing EMT process

Background: Lung cancer is a malignant tumor in mammary gland epithelium with high morbidity and mortality among women worldwide. Long noncoding RNA GAS5 (GAS5) has been proved to be closely related with tumor progression. However, the influence of GAS5 on lung cancer and the specific mechanism remain unclear.

Methods: Cell invasion, cell migration, cell apoptosis and cell cycle were investigated after transfection with pcDNA-GAS5 and sh-GAS5. Sizes of tumors were measured by establishing transplanted tumor model in vivo. E-cadherin and N-cadherin expressions were investigated.

Results: Cell invasion and migration were inhibited markedly in GAS5 overexpressed cell line. Cell cycle results indicated that the percentage of S-phase cells was increased, and G2-phase was reduced in the GAS5 overexpression cell line. Tumor size was suppressed obviously after GAS5 overexpression treatment. GAS5 markedly inhibited the expression of E-cadherin and induced the expression of N-cadherin. GAS5 overexpression significantly inhibited lung cancer cell proliferation by increasing the E-cadherin and decreasing N-cadherin.

Conclusions: These findings provide novel evidence that GAS5 can be viewed as an anti-lung cancer agent through affecting EMT pathway.

The function of LncRNAs and their role in the prediction, diagnosis, and prognosis of lung cancer

Lung cancer remains a major threat to human health. Low dose CT scan (LDCT) has become the main method of early screening for lung cancer due to the low sensitivity of chest X-ray. However, LDCT not only has a high false positive rate, but also entails risks of overdiagnosis and cumulative radiation exposure. In addition, cumulative radiation by LDCT screening and subsequent follow-up can increase the risk of lung cancer. Many studies have shown that long noncoding RNAs (lncRNAs) remain stable in blood, and profiling of blood has the advantages of being noninvasive, readily accessible and inexpensive. Serum or plasma assay of lncRNAs in blood can be used as a novel detection method to assist LDCT while improving the accuracy of early lung cancer screening. LncRNAs can participate in the regulation of various biological processes. A large number of researches have reported that lncRNAs are key regulators involved in the progression of human cancers through multiple action models. Especially, some lncRNAs can affect various hallmarks of lung cancer. In addition to their diagnostic value, lncRNAs also possess promising potential in other clinical applications toward lung cancer. LncRNAs can be used as predictive markers for chemosensitivity, radiosensitivity, and sensitivity to epidermal growth factor receptor (EGFR)-targeted therapy, and as well markers of prognosis. Different lncRNAs have been implicated to regulate chemosensitivity, radiosensitivity, and sensitivity to EGFR-targeted therapy through diverse mechanisms. Although many challenges need to be addressed in the future, lncRNAs have bright prospects as an adjunct to radiographic methods in the clinical management of lung cancer.

Matrine regulates H2O2-induced oxidative stress through long non-coding RNA HOTAIR/miR-106b-5p axis via AKT and STAT3 pathways

Matrine is a main active constituent of Chinese herb Sophora flavescens Ait (Kushen), which has shown various pharmacological effects, and has been reported to exhibit protective effects in heart failure. In the present study, the underlying mechanism of matrine was explored in H₂O₂-induced H9c2 cell line. It was confirmed that matrine could alleviate H₂O₂-induced injury in H9c2 cells. And the down-regulation of long non-coding RNA HOTAIR induced by H₂O₂ could be reversed by treating with matrine. Moreover, overexpression of HOTAIR promoted cell viability and superoxide dismutase (SOD) level, but inhibited cell apoptosis and lactate dehydrogenase (LDH) level. We found that miR-106b-5p was a target of HOTAIR and negatively regulated by HOTAIR. Moreover, up-regulation of miR-106b-5p restored the effects of HOTAIR overexpression on cell viability, apoptosis, and the levels of LDH and SOD. In addition, matrine protected H9c2 cells from H₂O₂-induced injury through HOTAIR/miR-106b-5p axis. Furthermore, we discovered that matrine exerted protective effects on H₂O₂-induced H9c2 cells through activating STAT3 and AKT pathway. In brief, matrine modulated H₂O₂-induced myocardial oxidative stress repair through HOTAIR/miR-106b-5p axis via AKT and STAT3 signaling pathway. Our study may provide a therapeutic target for the therapy of oxidative stress heart diseases.

Association between HOX Transcript Antisense RNA Single-Nucleotide Variants and Recurrent Implantation Failure

Recurrent implantation failure (RIF) refers to the occurrence of more than two failed in vitro fertilization–embryo transfers (IVF-ETs) in the same individual. RIF can occur for many reasons, including embryo characteristics, immunological factors, and coagulation factors. Genetics can also contribute to RIF, with some single-nucleotide variants (SNVs) reported to be associated with RIF occurrence. We examined SNVs in a long non-coding RNA, homeobox (HOX) transcript antisense RNA (HOTAIR), which is known to affect cancer development. HOTAIR regulates epigenetic outcomes through histone modifications and chromatin remodeling. We recruited 155 female RIF patients and 330 healthy controls, and genotyped HOTAIR SNVs, including rs4759314, rs920778, rs7958904, and rs1899663, in all participants. Differences in these SNVs were compared between the patient and control groups. We identified significant differences in the occurrence of heterozygous genotypes and the dominant expression model for the rs1899663 and rs7958904 SNVs between RIF patients and control subjects. These HOTAIR variants were associated with serum hemoglobin (Hgb), luteinizing hormone (LH), total cholesterol (T. chol), and blood urea nitrogen (BUN) levels, as assessed by analysis of variance (ANOVA). We analyzed the four HOTAIR SNVs and found significant differences in haplotype patterns between RIF patients and healthy controls. The results of this study showed that HOTAIR is not only associated with the development of cancer but also with pregnancy-associated diseases. This study represents the first report showing that HOTAIR is correlated with RIF.

Genetic impacts on thermostability of onco-lncRNA HOTAIR during the development and progression of endometriosis

HOTAIR is a well-known long non-coding RNA (lncRNA) involved in various cellular signaling, whereas its functional impacts on endometriosis development are still largely unknown. To this end, six potential functional single nucleotide polymorphisms (SNPs) in HOTAIR, with minor allele frequencies more than 10% in Han population and altered net energy of RNA structures larger than 0.5 kcal/mol, were selected for genotyping study. The study included 207 endometriosis patients and 200 healthy women. Genetic substitutions at rs1838169 and rs17720428 were frequently found in endometriosis patients, and rs1838169 showed statistical significance (p = 0.0174). The G-G (rs1838169-rs17720428) haplotype showed the most significant association with endometriosis (p < 0.0001) with enhanced HOTAIR stability, and patients who harbor such haplotype tended to show higher CA125. Data mining further revealed higher mRNA HOTAIR levels in the endometria of patients with severe endometriosis which consistently showed reduced HOXD10 and HOXA5 levels. HOTAIR knockdown with specific shRNAs down-regulated cell proliferation and migration with the induction of HOXD10 and HOXA5 expression in human ovarian clear cancer cells. Our study therefore provided evidence to indicate a prominent role of HOTAIR in promoting endometriosis, which could be used as a potential target for clinical applications.

Comprehensive analysis of the lncRNA-miRNA-mRNA regulatory network for bladder cancer

Background

Long non-coding RNAs (lncRNAs) are essential regulators for various human cancers. However, these lncRNAs need to be further classified for cancer. In the present study, we identified novel competing endogenous RNA (ceRNA) network for bladder cancer (BC) and explored the gene functions of the ceRNA regulatory network.

Methods

Differential gene expression analysis were performed on The Cancer Genome Atlas Urothelial Bladder Carcinoma (TCGA-BLCA) datasets to identify differentially expressed messenger RNAs (mRNAs), lncRNAs, and microRNAs (miRNAs). Based on the competing endogenous RNA (ceRNA) hypothesis, a lncRNA-miRNA-mRNA network was constructed using the StarBase database and visualization by Cytoscape software. Functional enrichment analyses of Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway were performed via R package ClusterProfiler. The protein-protein interaction network was constructed by STRING database and visualization by Cytoscape. Finally, we used CIBERSORT and the TIMER database to analyze the immune infiltrations for BC.

Results

The regulatory network was constructed via TCGA BLCA cohort. The differential expressions of lncRNA, miRNA, and mRNA were 186, 200, and 2,661, respectively. There were 106 lncRNA, miRNA, and mRNA included in the ceRNA network. In this network, Calcium Voltage-gated Channel Auxiliary Subunit Alpha2delta1 (CACNA2D1, P<0.001), domain containing engulfment adaptor1 (GULP1, P=0.001), latent transforming growth factor beta binding protein 1 (LTBP1, P=0.006), myosin light chain kinase (MYLK, P=0.001), serpin family E member 2 (SERPINE2, P=0.002), spectrin beta non-erythrocytic 2 (SPTBN2, P=0.047), and hsa-miR-590-3p (P<0.001) significantly affected the prognosis of BC patients. Functional enrichment analyses showed that the biological functions included negative regulation of protein phosphorylation, cell morphogenesis, and sensory organ morphogenesis. Important cancer pathways of KEGG included parathyroid hormone synthesis secretion action, the notch signaling pathway, MAPK signaling pathway, the Rap1 signaling pathway, signaling pathways regulating the pluripotency of stem cells, and the transforming growth factor-β signaling pathway. Our findings demonstrated that the ceRNA network has important biological functions and a significant influence on the prognosis of BC.

Conclusions

The lncRNA-miRNA-mRNA network constructed in the present study could provide useful insight into the underlying tumorigenesis of BC, and can determine new molecular biomarkers for the diagnosis and therapeutical treatment of BC.

Interaction Between LncRNA and UPF1 in Tumors

Long non-coding RNAs (LncRNAs) can bind to other proteins or RNAs to regulate gene expression, and its role in tumors has been extensively studied. A common RNA binding protein, UPF1, is also a key factor in a variety of RNA decay pathways. RNA decay pathways serve to control levels of particular RNA molecules. The expression of UPF1 is often dysregulated in tumors, an observation which suggests that UPF1 contributes to development of a variety of tumors. Herein, we review evidence from studies of fourteen lncRNAs interact with UPF1. The interaction between lncRNA and UPFI provide fundamental basis for cell transformation and tumorigenic growth.

The HOTAIR lncRNA: A remarkable oncogenic promoter in human cancer metastasis

Long non-coding RNA (lncRNA) is a new type of non-coding RNA that has an important regulatory influence on several human diseases, including cancer metastasis. HOX antisense intergenic RNA (HOTAIR), a newly discovered lncRNA, has an important effect on tumour proliferation, migration and metastasis. HOTAIR regulates cell proliferation, changes gene expression, and promotes tumour cell invasion and migration. However, its molecular mechanism of action remains unknown. The present review summarizes the molecular mechanism and role of HOTAIR in tumour invasion and metastasis, discusses the association between HOTAIR and tumour metastasis through different pathways, such as the transforming growth factor β, Wnt/β-catenin, PI3K/AKT/MAPK and vascular endothelial growth factor pathways, emphasizes the function of HOTAIR in human malignant tumour metastasis and provides a foundation for its application in the diagnosis, prognosis and medical treatment of various tumours.

LncRNA HOTAIR recruits SNAIL to inhibit the transcription of HNF4α and promote the viability, migration, invasion and EMT of colorectal cancer

l

HOTAIR recruited SNAIL and reduced the expression of HNF4α to promote EMT of colorectal cancer.

l

Provided potential novel long non-coding RNA-directed early diagnosis and therapy for colorectal cancer.

l

Provided further insight into the regulatory mechanism of HOTAIR in colorectal cancer.

Colorectal cancer causes severe burdensome on the health by its high fatality and poor prognosis. Hox transcript antisense intergenic RNA (HOTAIR) was believed closely related with the genesis and development of colorectal cancer, but the regulatory mechanism is still to be investigated. The expression of HOTAIR was analyzed in colorectal cancer using both qRT-PCR and ISH assay. The cell viability, migration, invasion and apoptosis rate were evaluated using MTT, BrdU,Transwell and flow cytometryexperiments. The interaction between HOTAIR and SNAIL was detected using RIP and RNA pull-down. The binding of SNAIL to HNF4α promoter was assessed by ChIP. The cell lines that knock down HOTAIR, SNAIL or overexpress HNF4α were constructed using retroviral vector system. The tumorigenic and metastatic capacity of colorectal cancer cells after knocking down HOTAIR were evaluated based on xenograft assay and liver metastases model. HOTAIR was highly expressed in both tissue and cell lines of colorectal cancer, indicated a regulatory function in colorectal cancer. Knock-down of HOTAIR suppressed cell viability, migration, invasion and epithelial-mesenchymal transition (EMT) of colorectal cancer cells in vitro, and inhibited the growth and metastasis of colorectal tumor in nude mice. We further found that HOTAIR suppressed HNF4α via recruiting SNAIL, and the overexpression of HNF4α inhibited cell viability, migration, invasion and EMT of colorectal cancer cells. We demonstrated that HOTAIR regulates the level of HNF4α via recruiting SNAIL, knocking down HOTAIR repressed the cell viability and metestasis of colorectal cancer cell line in vitro, and suppressed the tomorgenesis and migration/invasion of colorectal cancer in vivo.

Functional Interaction among lncRNA HOTAIR and MicroRNAs in Cancer and Other Human Diseases

Simple Summary

This review aimed to describe the contribution of functional interaction between the lncRNA HOTAIR and microRNAs in human diseases, including cancer. HOTAIR/miRNAs complexes interfere with different cellular processes during carcinogenesis, mainly deregulating a series of oncogenic signaling pathways. A great number of ncRNAs-related databases have been established, supported by bioinformatics technologies, to identify the ncRNA-mediated sponge regulatory network. These approaches need experimental validation through cells and animal models studies. The optimization of systems to interfere with HOTAIR/miRNAs interplay could represent a new tool for the definition of diagnostic therapeutics in cancer patients.

Abstract

LncRNAs are a class of non-coding RNAs mostly involved in regulation of cancer initiation, metastatic progression, and drug resistance, through participation in post-transcription regulatory processes by interacting with different miRNAs. LncRNAs are able to compete with endogenous RNAs by binding and sequestering miRNAs and thereby regulating the expression of their target genes, often represented by oncogenes. The lncRNA HOX transcript antisense RNA (HOTAIR) represents a diagnostic, prognostic, and predictive biomarker in many human cancers, and its functional interaction with miRNAs has been described as crucial in the modulation of different cellular processes during cancer development. The aim of this review is to highlight the relation between lncRNA HOTAIR and different microRNAs in human diseases, discussing the contribution of these functional interactions, especially in cancer development and progression.

LncRNA LINC00240 suppresses invasion and migration in non-small cell lung cancer by sponging miR-7-5p

Background

lncRNAs have important roles in regulating cancer biology. Accumulating evidence has established a link between the dysregulation of lncRNAs and microRNA in cancer progression. In previous studies, miR-7-5p has been found to be significantly down-regulated in mesenchymal-like lung cancer cell lines and directly regulated EGFR. In this work, we investigated the lncRNA partner of miR-7-5p in the progression of lung cancer.

Methods

We investigated the expression of miR-7-5p and the lncRNA after transfection with an miR-7-5p mimics using a microarray. The microarray results were validated using quantitative real time-polymerase Chain Reaction (qRT-PCR). The regulatory effects of lncRNA on miR-7-5p and its target were evaluated by changes in the expression of miR-7-5p after transfection with siRNAs for lncRNA and the synthesis of full-length lncRNA. The effect of miR-7-5p on lncRNA and the miRNA target was evaluated after transfection with miRNA mimic and inhibitor. The role of lncRNA in cancer progression was determined using invasion and migration assays. The level of lncRNA and EGFR in lung cancer and normal lung tissue was analyzed using TCGA data.

Results

We found that LINC00240 was downregulated in lung cancer cell line after miR-7-5p transfection with an miR-7-5p mimic. Further investigations revealed that the knockdown of LINC00240 induced the overexpression of miR-7-5p. The overexpression of miR-7-5p diminished cancer invasion and migration. The EGFR expression was down regulated after siRNA treatment for LINC00240. Silencing LINC00240 suppressed the invasion and migration of lung cancer cells, whereas LINC00240 overexpression exerted the opposite effect. The lower expression of LINC00240 in squamous lung cancer was analyzed using TCGA data.

Conclusions

Taken together, LINC00240 acted as a sponge for miR-7-5p and induced the overexpression of EGFR. LINC00240 may represent a potential target for the treatment of lung cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-020-07755-8.

LncRNA HOTAIR regulates glucose transporter Glut1 expression and glucose uptake in macrophages during inflammation

Inflammation plays central roles in the immune response. Inflammatory response normally requires higher energy and therefore is associated with glucose metabolism. Our recent study demonstrates that lncRNA HOTAIR plays key roles in NF-kB activation, cytokine expression, and inflammation. Here, we investigated if HOTAIR plays any role in the regulation of glucose metabolism in immune cells during inflammation. Our results demonstrate that LPS-induced inflammation induces the expression of glucose transporter isoform 1 (Glut1) which controls the glucose uptake in macrophages. LPS-induced Glut1 expression is regulated via NF-kB activation. Importantly, siRNA-mediated knockdown of HOTAIR suppressed the LPS-induced expression of Glut1 suggesting key roles of HOTAIR in LPS-induced Glut1 expression in macrophage. HOTAIR induces NF-kB activation, which in turn increases Glut1 expression in response to LPS. We also found that HOTAIR regulates glucose uptake in macrophages during LPS-induced inflammation and its knockdown decreases LPS-induced increased glucose uptake. HOTAIR also regulates other upstream regulators of glucose metabolism such as PTEN and HIF1α, suggesting its multimodal functions in glucose metabolism. Overall, our study demonstrated that lncRNA HOTAIR plays key roles in LPS-induced Glut1 expression and glucose uptake by activating NF-kB and hence HOTAIR regulates metabolic programming in immune cells potentially to meet the energy needs during the immune response.

Benzyl Butyl Phthalate Induced Early lncRNA H19 Regulation in C3H10T1/2 Stem Cell Line

Exposure to endocrine-disrupting chemicals used in plastic manufacturing may contribute to the current obesity and diabetes epidemic. Our previous study demonstrated that benzyl butyl phthalate (BBP) induced adipogenesis in the C3H10T1/2 stem cell line. Here we investigated if BBP deregulated long noncoding RNA H19 and its downstream pathway and whether BBP plays a role in the insulin signaling pathway during adipocyte diiferentiation. Cells treated with an 8 day BBP regimen showed that H19 expression was decreased at day 2 with 50 μM BBP exposure (p < 0.05). However, no significant changes were observed from day 4 to day 8. Expression of miRNA-103/107, H19 regulated miRNAs, was upregulated at day 2 (p < 0.05) but not from day 4 to day 8. Similarly, expression of the let-7 family members (a, b, c, d, f, and g) was also significantly increased at day 2 (p < 0.05 or p < 0.01), except for let-7e. Both let-7 and miRNA-103/107 are targets of H19 and play roles in insulin signaling. Insulin receptor substrate (IRS)-1, one of the key insulin signal transduction regulators, was significantly downregulated from day 2 to day 8 (p < 0.05). Gene expression of insulin receptor (IR) and IRS-2 were not altered by BBP exposure. The ratio of IRS1/IRS2 was significantly decreased from day 2 to day 8. On day 4, phospho-Akt protein expression was significantly decreased (p < 0.05). In conclusion, BBP exposure may lead to metabolic dysregulation by altering vital epigenetic regulators such as lncRNA H19 and its target microRNAs at an earlier stage, which further regulates insulin signaling.

Non-coding RNAs and potential therapeutic targeting in cancer

Recent advances have begun to clarify the physiological and pathological roles of non-coding RNAs (ncRNAs) in various diseases, including cancer. Among these, microRNAs (miRNAs) have been the most studied and have emerged as key players that are involved in the regulation of important growth regulatory pathways in cancer pathogenesis. The ability of a single ncRNA to modulate the expression of multiple downstream gene targets and associated pathways, have provided a rationale to pursue them for therapeutic drug development in cancer. In this context, early data from pre-clinical studies have demonstrated that synthetic miRNA-based therapeutic molecules, along with various protective coating approaches, has allowed for their efficient delivery and anti-tumor activity. In fact, some of the miRNA-based cancer therapeutic strategies have shown promising results even in early-phase human clinical trials. While the enthusiasm for ncRNA-based cancer therapeutics continue to evolve, the field is still in the midst of unraveling a more precise understanding of the molecular mechanisms and specific downstream therapeutic targets of other lesser studied ncRNAs such as the long-non-coding RNAs, transfer RNAs, circular RNAs, small nucleolar RNAs, and piwi-interacting RNAs. This review article provides the current state of knowledge and the evolving principles for ncRNA-based therapeutic approaches in cancer, and specifically highlights the importance of data to date and the approaches that are being developed to overcome the challenges associated with their delivery and mitigating the off-target effects in human cancers.

Association between Genetic Polymorphisms of miR-1307, miR- 1269, miR-3117 and Breast Cancer Risk in a Sample of South East Iranian Women

INTRODUCTION

MicroRNAs (miRNAs) play an essential role in the susceptibility and development of cancer cells.

OBJECTIVE

Examining the dependency of breast cancer risk with genetic polymorphisms of miR-1307, miR-1269, and miR-3117 in a sample of Iranian women (southeast region).

METHODS

The case-control study consisted of 520 individuals (260 diagnosed BC patients, 260 healthy individuals). The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used for genotyping of miR-1307 rs7911488, miR-1269 rs73239138, and miR-3117 (rs4655646 and rs7512692) polymorphisms.

RESULTS AND CONCLUSION

This study provided evidence that miR-1307 rs7911488 polymorphism significantly reduced the risk of BC in heterozygous AG genotype, as well as dominant (AG+GG) genotype and G allele. A significant correlation was found between dominant (AA+AG) genotype, the A allele and protection against BC due to miR-1269 rs73239138 in the sample of study. In contrast, our findings suggested that AG genotype and G allele of miR-3117 rs4655646 polymorphism could increase BC's susceptibility among the southeastern Iranian females. The miR-3117 rs7512692 variant also increased the risk of BC in codominant, dominant and recessive models, as well as the T allele. The possible dependency of miR-1307, miR-1269, and miR-3117 variants with patients' clinicopathological characteristics and BC was also studied. It was concluded that there is a correlation between miR-3117 rs7512692 variant and tumor grade (p=0.031); also, a correlation between miR-1269 rs73239138 variant and progesterone receptor status (p=0.006). The current investigation revealed that miR-1307, miR-1269, and miR-3117 polymorphisms might play a crucial role in the Iranian population's vulnerability to BC.<br />.

The Role of Exosomes in the Female Reproductive System and Breast Cancers

Exosomes are nanoscale extracellular vesicles released by nearly all cell types. Exosomes were originally considered as waste receptacles for discarding unwanted cellular products; however, these organelles are now considered to be important for cell communication by delivering biologically active molecules such as proteins, DNA, non-coding RNA and mRNA. Studies have revealed that exosomes are closely related to several diseases, especially cancers. Exosomes are indispensable for the emergence and progression of tumor. Here, we review the status of research on exosomes in the female reproductive system cancers and breast cancer, focusing on their biological roles in chemical resistance and immune responses, as well as their underlying applications in drug delivery and nanotherapy and as biological markers for tumor diagnosis.

Non-Coding RNAs as Mediators of Epigenetic Changes in Malignancies

Non-coding RNAs (ncRNAs) are untranslated RNA molecules that regulate gene expressions. NcRNAs include small nuclear RNAs (snRNAs), small nucleolar RNAs (snoRNAs), ribosomal RNAs (rRNAs), transfer RNAs (tRNAs), circular RNAs (cRNAs) and piwi-interacting RNAs (piRNAs). This review focuses on two types of ncRNAs: microRNAs (miRNAs) or short interfering RNAs (siRNAs) and long non-coding RNAs (lncRNAs). We highlight the mechanisms by which miRNAs and lncRNAs impact the epigenome in the context of cancer. Both miRNAs and lncRNAs have the ability to interact with numerous epigenetic modifiers and transcription factors to influence gene expression. The aberrant expression of these ncRNAs is associated with the development and progression of tumors. The primary reason for their deregulated expression can be attributed to epigenetic alterations. Epigenetic alterations can cause the misregulation of ncRNAs. The experimental evidence indicated that most abnormally expressed ncRNAs impact cellular proliferation and apoptotic pathways, and such changes are cancer-dependent. In vitro and in vivo experiments show that, depending on the cancer type, either the upregulation or downregulation of ncRNAs can prevent the proliferation and progression of cancer. Therefore, a better understanding on how ncRNAs impact tumorigenesis could serve to develop new therapeutic treatments. Here, we review the involvement of ncRNAs in cancer epigenetics and highlight their use in clinical therapy.

HOX transcript antisense RNA: An oncogenic lncRNA in diverse malignancies

HOX transcript antisense RNA (HOTAIR) is a transcript produced from the antisense strand of the HOXC gene cluster and influencing expression of genes from the HOXD locus. HOTAIR has prominent roles in different aspects of carcinogenic process from cancer initiation to metastasis. A number of in vitro, in vivo and human investigations have confirmed the oncogenic impacts of HOTAIR. The diagnostic power of HOTAIR in distinguishing cancer status from healthy status has been optimal in gastric cancer, pancreatic adenocarcinoma and colorectal cancer. The most important achievement in this regard has been provided by studies that verified diagnostic value of this lncRNA in the serum samples, potentiating its application in non-invasive diagnosis of cancer. Moreover, HOTAIR has a crucial role in determination of response of cancer cells to therapeutic modalities. The current review aims to explain the outlines of these studies to emphasize its potential as a biomarker and therapeutic target for these conditions.

Long noncoding RNAs: Potential therapeutic targets in cardiocerebrovascular diseases

Cardiocerebrovascular disease is a collective term for cardiovascular and cerebrovascular diseases. Because of the complex mechanisms involved in cardiocerebrovascular diseases, limited effective treatments have been developed. With advancements in precision medicine, studies have focused on long noncoding RNAs (lncRNAs) in cerebrovascular diseases. LncRNAs, which are over 200 nucleotides long, regulate gene expression at epigenetic, transcriptional, and post-transcriptional levels. Moreover, lncRNAs play pivotal roles in the progression of cardiocerebrovascular diseases. For example, recent studies suggested that abnormal expression of lncRNAs are closely related to the occurrence and progression of these diseases. LncRNAs regulate gene expression by specifically binding to mRNA to modulate disease progression, serving as biomarkers for the diagnosis and prognosis of cardiocerebrovascular diseases. In this review, we discuss the roles, mechanisms, and clinical value of lncRNAs in cardiocerebrovascular diseases, providing a new perspective for the diagnosis and treatment of the diseases.

Prognostic and clinical significance of long non-coding RNA SNHG12 expression in various cancers

Recently, increasing studies suggested that lncRNA SNHG12 was aberrantly expressed in kinds of cancers. However, definite prognostic value of SNHG12 remains unclear. We conducted this meta-analysis to evaluate the association between SNHG12 expression level and cancer prognosis. A literature retrieval was conducted by searching kinds of databases. The meta-analysis was performed by using Revman 5.2 and Stata 12.0 software. Besides, The Cancer Genome Atlas dataset was analyzed to validate the results in our meta-analysis via using Gene Expression Profiling Interactive Analysis. The pooled results showed that high SNHG12 expression significantly indicated worse overall survival and recurrence-free survival. Tumor type, sample size, survival analysis method, and cutoff value did not alter SNHG12 prognosis value according to stratified analysis results. Additionally, higher expression of SNHG12 suggested unfavorable clinicopathological outcomes including larger tumor size, lymph node metastasis, distant metastasis, and advanced clinical stage. Online cross-validation in TCGA dataset further indicated that cancer patients with upregulated SNHG12 expression had worse overall survival and disease-free survival. Therefore, elevated SNHG12 expression was associated with poor survival and unfavorable clinical outcomes in various cancers, and therefore might be a potential prognostic biomarker in human cancers.

Abbreviations Akt: protein kinase B; CESC: cervical squamous cell carcinoma and endocervical adenocarcinoma; ceRNA: competitive endogenous RNA; CNKI: China National Knowledge Infrastructure; CI: confidence interval; CCNE1: cyclin E1; COAD: colon adenocarcinoma; DM: distant metastasis; DFS: disease-free survival; EMT: epithelial–mesenchymal transition; FISH: fluorescence in situ hybridization; FIGO: the International Federation of Gynecology and Obstetrics; GEPIA: Gene Expression Profiling Interactive Analysis; HR: hazard ratio; HIFα: hypoxia-inducible factor 1 α; KIRC: kidney renal clear cell carcinoma; KIRP: kidney renal papillary cell carcinoma; LIHC: hepatocellular carcinoma; LNM: lymph node metastasis; mTOR: mechanistic target of rapamycin kinase; MMP-9: matrix metalloproteinase 9; MCL1: myeloid cell leukemia 1; MLK3: mixed-lineage protein kinase 3; N/A: not available; NOS: Newcastle-Ottawa Scale; OR: odd ratio; OS: overall survival; PSA: prostate-specific antigen; PI3K: phosphoinositide 3-kinase; qRT-PCR: quantitative real-time polymerase chain reaction; READ: rectum adenocarcinoma; RFS: recurrence-free survival; SARC: sarcoma; SNHG12: small nucleolar RNA host gene 12; STAT3: signal transducer and activator of transcription 3; SOX4: SRY-box transcription factor 4; SOX5: SRY-box transcription factor 5; STAD: stomach adenocarcinoma; TCGA: The Cancer Genome Atlas; TNM: tumor node metastasis; WWP1: WW domain-containing E3 ubiquitin protein ligase 1; WHO grade: World Health Organization grade; ZEB2: zinc finger E-box-binding homeobox 2

Aberrant Methylation of the SOX21-AS1 Promoter Region Promotes Gene Expression and Its Clinical Value in Cervical Cancer

Cervical cancer is the fourth most common female cancer worldwide. Long non-coding RNAs (lncRNAs), such as SOX21-AS1, play pivotal roles in the progression and metastasis of cancer. We previously described that SOX21-AS1 was hypomethylated in cervical cancer (CC) and aimed to further explore the relationship between methylation of the SOX21-AS1 promoter and CC using clinical cervical samples. Pyrosequencing was performed to detect the methylation status of the SOX21-AS1 promoter in 33 cervical specimens. Additionally, expression levels of related genes in 43 clinical cervical specimens were measured using quantitative real-time PCR (qRT-PCR). The SOX21-AS1 promoter was significantly hypomethylated in CC (P < 0.01). SOX21-AS1 hypomethylation was also significantly associated with an advanced Federation of Gynecology and Obstetrics (FIGO) stage (P < 0.01). The expression levels of SOX21-AS1 and SOX21 were noted to be higher in cancer vs. normal cervix (all P < 0.001). Moreover, the expression of SOX21-AS1 was positively correlated with SOX21 in all samples (r = 0.891, P < 0.001). Methylation statue of the SOX21-AS1 promoter region was negatively correlated with the expression levels of SOX21-AS1 and SOX21 (SOX21-AS1, r = - 0.628; SOX21, r = - 0.648; both P < 0.001). The methylation status of SOX21-AS1 displayed promising diagnostic potential for CC, exhibiting good sensitivity (100.0%) and specificity (69.2%), with an area under the curve of 0.846. In addition, bioinformatic analyses identified a potential link between SOX21-AS1 and the Wnt signaling pathway. Furthermore, methylation status of SOX21-AS1 was negatively correlated with β-catenin/c-myc/cyclin D1 mRNA levels (r_s = - 0.529, - 0.462 ,and - 0.383, respectively, P < 0.05). Our findings illuminated that lncRNA SOX21-AS1 showed hypomethylation in cervical cancer and SOX21-AS1 could serve as a novel biomarker for CC diagnosis or a potential therapeutic target.

Preeclampsia-Associated lncRNA INHBA-AS1 Regulates the Proliferation, Invasion, and Migration of Placental Trophoblast Cells

Preeclampsia is believed to be caused by impaired placentation with insufficient trophoblast invasion, leading to impaired uterine spiral artery remodeling and angiogenesis. However, the underlying molecular mechanism remains unknown. We recently carried out transcriptome profiling of placental long noncoding RNAs (lncRNAs) and identified 383 differentially expressed lncRNAs in early-onset severe preeclampsia. Here, we are reporting our identification of lncRNA INHBA-AS1 as a potential causal factor of preeclampsia and its downstream pathways that may be involved in placentation. We found that INHBA-AS1 was upregulated in patients and positively correlated with clinical severity. We systematically searched for potential INHBA-AS1-binding transcription factors and their targets in databases and found that the targets were enriched with differentially expressed genes in the placentae of patients. We further demonstrated that the lncRNA INHBA-AS1 inhibited the invasion and migration of trophoblast cells through restraining the transcription factor CENPB from binding to the promoter of TNF receptor-associated factor 1 (TRAF1). Therefore, we have identified the dysregulated pathway "INHBA-AS1-CENPB-TRAF1" as a contributor to the pathogenesis of preeclampsia through prohibiting the proliferation, invasion, and migration of trophoblasts during placentation.

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

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

Long noncoding RNA LINC00261 suppresses prostate cancer tumorigenesis through upregulation of GATA6-mediated DKK3

Background

Prostate cancer is one of the leading causes of cancer death in males. Recent studies have reported aberrant expression of lncRNAs in prostate cancer. This study explores the role of LINC00261 in prostate cancer progression.

Methods

The differentially expressed genes, transcription factors, and lncRNAs related to prostate cancer were predicted by bioinformatics analysis. Prostate cancer tissue samples and cell lines were collected for the determination of the expression of LINC00261 by reverse transcription quantitative polymerase chain reaction. The binding capacity of LINC00261 to the transcription factor GATA6 was detected by RIP, and GATA6 binding to the DKK3 promoter region was assessed by ChIP. In addition, luciferase reporter system was used to verify whether LINC00261 was present at the DKK3 promoter. After gain- and loss-of function approaches, the effect of LINC00261 on prostate cancer in vitro and in vivo was assessed by the determination of cell proliferation, invasion and migration as well as angiogenesis.

Results

LINC00261, GATA6, and DKK3 were poorly expressed in prostate cancer. LINC00261 could inhibit transcriptional expression of DKK3 by recruiting GATA6. Overexpression of LINC00261 inhibited prostate cancer cells proliferation, migration, and invasion as well as angiogenesis, which could be reversed by silencing DKK3. Furthermore, LINC00261 could also suppress the tumorigenicity of cancer cells in vivo.

Conclusions

Our study demonstrates the inhibitory role of LINC00261 in prostate cancer progression, providing a novel biomarker for early detection of prostate cancer.

LINC01087 is Highly Expressed in Breast Cancer and Regulates the Malignant Behavior of Cancer Cells Through miR-335-5p/Rock1

PURPOSE

Long non-coding RNA is involved in the genesis and development of various tumors, and it has been found through database screening that LINC01087 is highly expressed in breast cancer (BC), but mechanisms of LINC01087 in BC are still under investigation. Therefore, this study aimed to study relevant mechanisms of LINC01087 in BC to provide potential therapeutic targets for the disease in clinic practice.

PATIENTS AND METHODS

The qRT-PCR assay was applied to determine the LINC01087 expression in BC, and the cell counting kit-8 (CCK8) assay, transwell assay, and flow cytometry were used to analyze the proliferation, apoptosis, and invasion of breast cancer cells (BCCs), respectively. The Western blot assay was used to determine the ROCK1 expression, and the luciferase reporter gene assay, RNA-binding protein immunoprecipitation (RIP), and RNA pull-down assays were applied to study the interaction between LINC01087 and miR-335-5p. Moreover, tumor xenotransplantation was conducted in nude mice to explore the effects of LINC01087 on BCCs.

RESULTS

The qRT-PCR assay revealed that the LINC01087 expression in BC tissues was higher than that in corresponding tumor-adjacent tissues, and survival analysis revealed an unfavorable prognosis of patients with high expression of LINC01087. Down-regulation of LINC01087 could slow down the proliferation, invasion, and migration of BCCs and accelerate apoptosis of them in vitro. Luciferase reporter gene assay results revealed that LINC01087 enhanced the expression of ROCK1 by regulating miR-335-5p, and LINC01087 could be adopted as a miR-335-5p sponge to inhibit ROCK1 expression.

CONCLUSION

LINC01087 is overexpressed in cases with BC, and patients with high expression of it suffer a poor survival. Furthermore, LINC01087 can act as a miR-335-5p sponge to affect the expression of ROCK1 and affect the invasion and migration of BCCs.

LncMirNet: Predicting LncRNA-miRNA Interaction Based on Deep Learning of Ribonucleic Acid Sequences

Long non-coding RNA (LncRNA) and microRNA (miRNA) are both non-coding RNAs that play significant regulatory roles in many life processes. There is cumulating evidence showing that the interaction patterns between lncRNAs and miRNAs are highly related to cancer development, gene regulation, cellular metabolic process, etc. Contemporaneously, with the rapid development of RNA sequence technology, numerous novel lncRNAs and miRNAs have been found, which might help to explore novel regulated patterns. However, the increasing unknown interactions between lncRNAs and miRNAs may hinder finding the novel regulated pattern, and wet experiments to identify the potential interaction are costly and time-consuming. Furthermore, few computational tools are available for predicting lncRNA-miRNA interaction based on a sequential level. In this paper, we propose a hybrid sequence feature-based model, LncMirNet (lncRNA-miRNA interactions network), to predict lncRNA-miRNA interactions via deep convolutional neural networks (CNN). First, four categories of sequence-based features are introduced to encode lncRNA/miRNA sequences including k-mer (k = 1, 2, 3, 4), composition transition distribution (CTD), doc2vec, and graph embedding features. Then, to fit the CNN learning pattern, a histogram-dd method is incorporated to fuse multiple types of features into a matrix. Finally, LncMirNet attained excellent performance in comparison with six other state-of-the-art methods on a real dataset collected from lncRNASNP2 via five-fold cross validation. LncMirNet increased accuracy and area under curve (AUC) by more than 3%, respectively, over that of the other tools, and improved the Matthews correlation coefficient (MCC) by more than 6%. These results show that LncMirNet can obtain high confidence in predicting potential interactions between lncRNAs and miRNAs.

The Interplay between Long Noncoding RNAs and Proteins of the Epigenetic Machinery in Ovarian Cancer

Comprehensive large-scale sequencing and bioinformatics analyses have uncovered a myriad of cancer-associated long noncoding RNAs (lncRNAs). Aberrant expression of lncRNAs is associated with epigenetic reprogramming during tumor development and progression, mainly due to their ability to interact with DNA, RNA, or proteins to regulate gene expression. LncRNAs participate in the control of gene expression patterns during development and cell differentiation and can be cell and cancer type specific. In this review, we described the potential of lncRNAs for clinical applications in ovarian cancer (OC). OC is a complex and heterogeneous disease characterized by relapse, chemoresistance, and high mortality rates. Despite advances in diagnosis and treatment, no significant improvements in long-term survival were observed in OC patients. A set of lncRNAs was associated with survival and response to therapy in this malignancy. We manually curated databases and used bioinformatics tools to identify lncRNAs implicated in the epigenetic regulation, along with examples of direct interactions between the lncRNAs and proteins of the epigenetic machinery in OC. The resources and mechanisms presented herein can improve the understanding of OC biology and provide the basis for further investigations regarding the selection of novel biomarkers and therapeutic targets.

LncRNA-NEF regulated the hyperoxia-induced injury of lung epithelial cells by FOXA2

INTRODUCTION

Hyperoxia-induced injury is a common form of damage in lung tissues, which could lead to bronchopulmonary dysplasia (BPD) in newborns. Recent studies have discovered that FOXA2 played a substantial role in protecting lung tissues from various injuries and lncRNA-NEF could activate the expression of FOXA2. However, it is unclear whether lncRNA-NEF could alleviate hyperoxia-caused damage of lung tissues by activating FOXA2.

MATERIAL AND METHODS

In this study, we used the lentivirus to establish the lncRNA-NEF overexpression RLE-6TN and MLE-12 cells. After that, the lentivirus was also used to knockdown the expression of FOXA2 in the two lncRNA-NEF overexpression cells. ELISA was performed to detect the levels of TNF-α, IL-1β and IL-6. The production of ROS, SOD, MDA and LDH was determined with the commercial kits. The apoptosis rates of these cells were measured with the flow cytometry.

RESULTS

The secretion of TNF-α, IL-1β and IL-6 was inhibited in RLE-6TN and MLE-12 cells after the overexpression of lncRNA-NEF. Furthermore, the production of ROS, MDA and LDH was also suppressed after the upregulation of lncRNA-NEF. The promotion of lncRNA-NEF also restricted the hyperoxia-induced apoptosis. However, the knockdown of FOXA2 abolished all the inhibitory effects exerted by lncRNA-NEF.

CONCLUSION

LncRNA-NEF regulated hyperoxia-caused inflammatory response, oxidative damage and apoptosis of RLE-6TN and MLE-12 cells by affecting the expression of FOXA2.

Natural antisense transcripts in the biological hallmarks of cancer: powerful regulators hidden in the dark

Natural antisense transcripts (NATs), which are transcribed from opposite strands of DNA with partial or complete overlap, affect multiple stages of gene expression, from epigenetic to post-translational modifications. NATs are dysregulated in various types of cancer, and an increasing number of studies focusing on NATs as pivotal regulators of the hallmarks of cancer and as promising candidates for cancer therapy are just beginning to unravel the mystery. Here, we summarize the existing knowledge on NATs to highlight their underlying mechanisms of functions in cancer biology, discuss their potential roles in therapeutic application, and explore future research directions.

Non-coding RNAs: the new central dogma of cancer biology

The central dogma of molecular biology states that the functions of RNA revolve around protein translation. Until the last decade, most researches were geared towards characterization of RNAs as intermediaries in protein translation, namely, messenger RNAs (mRNAs) as temporary copies of genetic information, ribosomal RNAs (rRNAs) as a main component of ribosome, or translators of codon sequence (tRNAs). The statistical reality, however, is that these processes account for less than 2% of the genome, and insufficiently explain the functionality of 98% of transcribed RNAs. Recent discoveries have unveiled thousands of unique non-coding RNAs (ncRNAs) and shifted the perception of them from being "junk" transcriptional products to "yet to be elucidated"-and potentially monumentally important-RNAs. Most ncRNAs are now known as key regulators in various networks in which they could lead to specific cellular responses and fates. In major cancers, ncRNAs have been identified as both oncogenic drivers and tumor suppressors, indicating a complex regulatory network among these ncRNAs. Herein, we provide a comprehensive review of the various ncRNAs and their functional roles in cancer, and the pre-clinical and clinical development of ncRNA-based therapeutics. A deeper understanding of ncRNAs could facilitate better design of personalized therapeutics.

Long non-coding RNA-polycomb intimate rendezvous

The interaction between polycomb-repressive complexes 1/2 (PRC1/2) and long non-coding RNA (lncRNA), such as the X inactive specific transcript Xist and the HOX transcript antisense RNA (HOTAIR), has been the subject of intense debate. While cross-linking, immuno-precipitation and super-resolution microscopy argue against direct interaction of Polycomb with some lncRNAs, there is increasing evidence supporting the ability of both PRC1 and PRC2 to functionally associate with RNA. Recent data indicate that these interactions are in most cases spurious, but nonetheless crucial for a number of cellular activities. In this review, we suggest that while PRC1/2 recruitment by HOTAIR might be direct, in the case of Xist, it might occur indirectly and, at least in part, through the process of liquid-liquid phase separation. We present recent models of lncRNA-mediated PRC1/2 recruitment to their targets and describe potential RNA-mediated roles in the three-dimensional organization of the nucleus.

Regulation of a long noncoding RNA MALAT1 by aryl hydrocarbon receptor in pancreatic cancer cells and tissues

Environmental toxicants such as dioxins and polycyclic aromatic carbons are risk factors for pancreatitis and pancreatic cancer. These toxicants activate aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor, of which activation regulates many downstream biological events, including xenobiotic metabolism, inflammation, and cancer cell growth and transformation. Here, we identified that environmental toxicant-activated AHR increased expression of metastasis associated lung adenocarcinoma transcript 1 (MALAT1) in pancreatic cancer cells and pancreatic tissues. The MALAT1 is a long noncoding (lnc) RNA which interacts with Enhancer of Zeste 2 (EZH2), a histone methyltransferase with epigenetic silencer activity, and the MALAT1-EZH2 interaction increased its epigenetic silencing activity. In contrast, AHR antagonist, CH223191 or resveratrol, counteracted the AHR-mediated MALAT1 induction and MALAT1-enahnced EZH2 activity. Collectively, these results revealed a novel pathway of how environmental exposure leads to epigenetic alteration via activation of AHR-MALAT1-EZH2 signaling axis under pancreatic tissue- and cancer cell-context.

LncRNA SNAI3-AS1 promotes PEG10-mediated proliferation and metastasis via decoying of miR-27a-3p and miR-34a-5p in hepatocellular carcinoma

During recent years, long noncoding RNAs (lncRNAs) have received focal attention due to their important function in cancer regulation. Though the relation between lncRNA SNAI3-AS1 and the development of hepatocellular carcinoma (HCC) has been described in our previous study, the role and the exact mechanism of SNAI3-AS1 are still unclear. In this study, qRT-PCR analysis revealed that the expression of SNAI3-AS1 was elevated and was correlated with the levels of PEG10 in HCC tissues. Through functional experiments, we determined that knockdown of SNAI3-AS1 and PEG10 inhibited the proliferation and metastasis, whereas overexpression of SNAI3-AS1 and PEG10 promoted the proliferation and metastasis of HCC cells. In addition, rescue experiments confirmed that upregulation of PEG10 partially restored cell function inhibition induced by SNAI3-AS1 knockdown. Therefore, we hypothesized that PEG10 may be regulated by SNAI3-AS1, which in turn mediates the malignant biological processes of HCC cells regulated by PEG10. Further bioinformatics analysis and mechanistic experiments showed that SNAI3-AS1 functions as a competing endogenous RNA (ceRNA) to activate PEG10 by acting as a sponge for miR-27-3p and miR-34a-5p. In summary, our study revealed that SNAI3-AS1 is a tumor regulator of PEG10 in the progression of HCC, and may contribute to the improvement of HCC diagnosis and therapy.