Competing endogenous RNA networks in human cancer: hypothesis, validation, and perspectives

Identification and regulation pattern analysis of long noncoding RNAs in meibomian gland carcinoma

Aim: To identify long noncoding RNAs (lncRNAs) and to elucidate regulation patterns of lncRNAs in meibomian gland carcinoma (MGC). Materials & methods: We used RNA-Seq, gene ontology, ClueGO, Ingenuity Pathway Analysis and co-expression network analyses to profile the expression and regulation patterns of lncRNAs and mRNAs in MGC. Results: We identified 500 lncRNAs and 326 mRNAs as differentially expressed. Co-expression regulatory networks with lncRNAs and mRNAs were constructed. The differentially expressed mRNAs and lncRNAs were enriched by fundamental biological functions that are implicated in the inflammatory signaling pathway and tumor proliferation (IL6 and PTGS2). Conclusion: LncRNAs might play important roles via the competing endogenous RNA regulation pattern in MGC tumorigenesis and contribute to the molecular pathogenesis of MGC.

Unmasking the pathological and therapeutic potential of histone deacetylases for liver cancer

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer, currently ranking as one of the highest neoplastic-related mortalities in the world. Due to the difficulty in early diagnosis and lack of effective treatment options, the 5-year survival rate of HCC remains extremely low. Histone deacetylation is one of the most important epigenetic mechanisms, regulating cellular events such as differentiation, proliferation and cell cycle. Histone deacetylases (HDACs), the chief mediators of this epigenetic mechanism, are often aberrantly expressed in various tumours including HCC. Areas covered: This review focuses on the most up-to-date findings of HDACs and their associated molecular mechanisms in HCC onset and progression. In addition, a potential network between HDACs and non-coding RNAs including microRNAs and long noncoding RNAs underlying hepatocarcinogenesis is considered. Expert opinion: Unmasking the role of HDACs and their association with HCC pathogenesis could have implications for future personalized therapeutic and diagnostic targeting.

Competing endogenous RNA networks in cervical cancer: function, mechanism and perspective

In the past several years, competing endogenous RNAs (ceRNAs) have emerged as a potential class of post-transcriptional regulators that alter gene expression through a microRNA (miRNA)-mediated mechanism. An increasing number of studies have found that ceRNAs play important roles in tumorigenesis. Cervical cancer is one of the most common cancers in female malignancies. Despite advances in our understanding of this neoplasm, patients with advanced cervical cancer still have poor prognosis. There is an urgent need to provide a new insight on the mechanism of cervical cancer development and may be acted as new anticancer therapeutic strategies. Here, we review the ceRNA studies and coherent researches in cervical cancer, especially in long non-coding RNA (lncRNA) and miRNAs in order to broaden horizons into mechanisms, selection biomarkers for diagnosis as well as predicting prognosis, and targeting treatment for cervical cancer in the future.

Long noncoding RNA NEAT1 promotes cell proliferation, migration, and invasion in hepatocellular carcinoma through interacting with miR-384

It was reported that long non-coding RNA nuclear-enriched abundant transcript 1 (NEAT1) is involved in hepatocellular carcinoma (HCC). However, the underlying mechanism of tumorigenesis is still largely unclear. Here, we found that NEAT1 is remarkably upregulated in HCC tissues and cell lines. Overexpression of NEAT1 notably accelerated HCC cell proliferation, migration, and invasion. Knockdown of NEAT1 significantly inhibited HCC cell proliferation, migration and invasion. MiR-384 expression was lower in HCC tissues and cell lines than adjacent nontumor tissues and L02 cell. MiR-384 exhibited the functions of tumor-suppressive. The expression of miR-384 was negatively correlated with the expression of NEAT1. Overexpression of NEAT1 reduced miR-384 expression, whereas inhibition of miR-384 led to a distinct upregulation of NEAT1 expression. In addition, we provided evidence that miR-384 was directly bound to the sequence of NEAT1 by luciferase reporter and RNA-binding protein immunoprecipitation assays. Overexpression of miR-384 inhibited NEAT1 function. Thus, we demonstrated that NEAT1 promotes the malignant biological properties of hepatocellular carcinoma by negatively regulating miR-384.

Biological functions of circular RNAs and their roles in occurrence of reproduction and gynecological diseases

Circular RNAs (circRNAs) are a large class of non coding endogenous RNAs in eukaryotic that are formed through 3'-5' ligation of a single RNA molecule. According to the different sources of the sequences, circRNA can be divided into three types: exon circRNA (ecRNA), intron circRNA (ciRNA), and exon-intron circRNA. Accumulating studies have shown that circRNAs are abundant, diverse, stable, and cell or tissue specific expression, etc. CircRNA plays a regulating role in gene expression, and an essential role in the process of biological development, such as miRNA sponges, endogenous RNAs and biomarkers, as well as critical role in the diagnosis of diseases. Studies have verified the interplay between circRNAs and the development of embryos, sperms, ovarian epithelial tumors, endometrial cancer and preeclampsia, suggesting the potential of circRNAs to become biomarkers or therapeutical targets for human diseases. In this paper, we reviewed the researches on circRNAs' characteristics, databases of circRNA, high-throughput sequencing of circRNA, and effect on reproductive and gynecological diseases.

GAS5 Regulates RECK Expression and Inhibits Invasion Potential of HCC Cells by Sponging miR-135b

Objectives

Long noncoding RNA (LncRNA) growth arrest-specific 5 (GAS5) has been characterized as a tumor suppressor in numerous kinds of human cancers. Its anticancer function in hepatocellular carcinoma (HCC) includes repression of cell proliferation and metastasis, leaving the internal mechanisms unclear. In this study, we intended to examine the anti-invasion effects of GAS5 on HCC and explore the downstream regulatory mechanisms.

Methods

Expression of GAS5 and microRNA-135b (miR-135b) was analyzed by qRT-PCR in paired HCC tissue samples. Their correlation with HCC patients' survival was determined. Transwell assays were done to evaluate in vitro invasion ability. Targeting of GAS5 and RECK by miR-135b was confirmed by qRT-PCR, western blot, and luciferase reporter assays.

Results

Decreased GAS5 and increased miR-135b in HCC inversely correlate with each other and both correlate with poor prognosis of HCC patients. Functionally, GAS5 suppresses while miR-135b promotes HCC cell invasion capacities in vitro. Mechanistically, GAS5 is a target of miR-135b. Furthermore, GAS5 positively regulates expression of RECK, also a target of miR-135b, which further inhibits MMP-2 expression and contributes to invasion repression.

Conclusion

GAS5 acted as a tumor suppressor in HCC invasion in a competing endogenous RNA manner. Our findings indicate that GAS5 is a promising therapeutic target for HCC treatment.

Long Noncoding RNAs: Emerging Players in Medulloblastoma

Central Nervous System tumors are the leading cause of cancer-related death in children, and medulloblastoma has the highest incidence rate. The current therapies achieve a 5-year survival rate of 50-80%, but often inflict severe secondary effects demanding the urgent development of novel, effective, and less toxic therapeutic strategies. Historically identified on a histopathological basis, medulloblastoma was later classified into four major subgroups-namely WNT, SHH, Group 3, and Group 4-each characterized by distinct transcriptional profiles, copy-number aberrations, somatic mutations, and clinical outcomes. Additional complexity was recently provided by integrating gene- and non-gene-based data, which indicates that each subclass can be further subdivided into specific subtypes. These deeper classifications, while getting over the typical tumor heterogeneity, indicate that different forms of medulloblastoma hold different molecular drivers that can be successfully exploited for a greater diagnostic accuracy and for the development of novel, targeted treatments. Long noncoding RNAs are transcripts that lack coding potential and play relevant roles as regulators of gene expression in mammalian differentiation and developmental processes. Their cell type- and tissue-specificity, higher than mRNAs, make them more informative about cell- type identity than protein-coding genes. Remarkably, about 40% of long noncoding RNAs are expressed in the brain and their aberrant expression has been linked to neuro-oncological disorders. However, while their involvement in gliomas and neuroblastomas has been extensively studied, their role in medulloblastoma is still poorly explored. Here, we present an overview of current knowledge regarding the function played by long noncoding RNAs in medulloblastoma biology.

RNA Interference Technology

RNA interference (RNAi) is the biological process of mRNA degradation induced by complementary sequences double-stranded (ds) small interfering RNAs (siRNA) and suppression of target gene expression. Exogenous siRNAs (perfectly paired dsRNAs of ∼21–25 nt in length) play an important role in host defense against RNA viruses and in transcriptional and post-transcriptional gene regulation in plants and other eukaryotes. Using RNAi technology by transfecting synthetic siRNAs into eukaryotic cells to silence genes has become an indispensable tool to investigate gene functions, and siRNA-based therapy is being developed to knockdown genes implicated in diseases. Other examples of RNAi technology include method of producing highly potent and purified siRNAs directly from Escherichiacoli cells, based on an unexpected discovery that ectopic expression of p19, a plant viral siRNA-binding protein, stabilizes a cryptic siRNA-like RNA species in bacteria. Those siRNAs, named as pro-siRNA for “prokaryotic siRNA”, are bacterial RNase III products that have chemical and functional properties that like eukaryotic siRNAs.

Circular RNA PVT1 acts as a competing endogenous RNA for miR-497 in promoting non-small cell lung cancer progression

Circular RNAs (circRNAs) are a class of covalently closed non-coding RNAs and play crucial regulatory roles in human cancer biology. The purpose of the present study was to explore the expression pattern and biological role of circular RNA PVT1 (circPVT1) in non-small cell lung cancer (NSCLC). We firstly found that circPVT1 was overexpressed in clinical NSCLC tissues and cell lines. NSCLC patients with high expression of circPVT1 exhibited aggressive clinicopathological characteristics and poor prognosis. In vitro assays of the NSCLC cell lines (H1299 and A549 cells) demonstrated that knockdown of circPVT1 inhibited NSCLC cell proliferation and induced NSCLC cell apoptosis. We further found that circPVT1 served as a competing endogenous RNA of miR-497 and indirectly regulated Bcl-2 expression in NSCLC cells. Finally, inhibition of miR-497 abrogated the effects of circPVT1 knockdown in NSCLC cells. Taken together, the results from our study indicated circPVT1 acts as an oncogene in NSCLC, and may serve as a promising therapeutic target for NSCLC patients.

Pseudogenes as Functionally Significant Elements of the Genome

Pseudogene is a gene copy that has lost its original function. For a long time, pseudogenes have been considered as "junk DNA" that inevitably arises as a result of ongoing evolutionary process. However, experimental data obtained during recent years indicate this understanding of the nature of pseudogenes is not entirely correct, and many pseudogenes perform important genetic functions. In the review, we have addressed classification of pseudogenes, methods of their detection in the genome, and the problem of their evolutionary conservatism and prevalence among species belonging to different taxonomic groups in the light of modern data. The mechanisms of gene expression regulation by pseudogenes and the role of pseudogenes in pathogenesis of various human diseases are discussed.

Construction and analysis of the lncRNA‑miRNA‑mRNA network based on competitive endogenous RNA reveals functional genes in heart failure

Heart failure (HF) is a principal cause of morbidity and mortality worldwide, affecting an estimated 38 million people. Although significant progress has been made with respect to the underlying molecular mechanisms, the role of the competing endogenous RNA (ceRNA) network in the pathogenesis of HF remains largely unknown. In this study, an HF-associated ceRNA network was constructed based on the differentially expressed long noncoding RNAs (lncRNAs), microRNAs (miRNAs) and mRNAs obtained, respectively, from the GSE77399, GSE104150 and GSE84796 datasets. The ceRNA network consisted of 12 lncRNA nodes, 43 miRNA nodes, 343 mRNA nodes and 530 edges. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis demonstrated that the ceRNA network was primarily enriched in the immune response, inflammatory response and T cell and B cell receptor signaling pathways. In addition, three lncRNAs (growth arrest specific 5, taurine upregulated 1 and HOX transcript antisense RNA) and three miRNAs [hsa-miRNA (miR)-26b-5p, hsa-miR-8485 and hsa-miR-940] with higher node degrees compared with other genes were selected as hub nodes. The expression of hub nodes in patients with HF was verified by reverse transcription-quantitative polymerase chain reaction analysis. The present study provided further insights into the important roles of the ceRNA network in HF development, and indicated the potential use of these hub nodes as diagnostic biomarkers and therapeutic targets.

Long non-coding RNA 1308 promotes cell invasion by regulating the miR-124/ADAM 15 axis in non-small-cell lung cancer cells

Purpose

Emerging evidence suggests that many differentially expressed long non-coding RNAs (lncRNAs) are involved in tumorigenesis. However, the functional roles of these transcripts and the mechanisms responsible for their deregulation in non-small-cell lung cancer (NSCLC) remain elusive. Here, we identified a novel lncRNA (lncRNA 1308), which was significantly upregulated in NSCLC tissues and investigated its biological function and potential molecular mechanism.

Methods

Differences in the lncRNA expression profiles between NSCLC and tumor-adjacent normal tissues were assessed by lncRNA expression microarray analysis. The microRNA in vivo precipitation (miRIP) method was used to identify the targeting microRNAs (miRNAs) on lncRNA 1308, and luciferase reporter assays were performed. Loss-of-function studies were used to explore the effect of lncRNA 1308 on lung carcinogenesis in NSCLC cells.

Results

The novel lncRNA 1308 was upregulated in NSCLC tissues and cell lines. By using biotin-labeled lncRNA 1308 for miRIP in NSCLC cells and dual-luciferase reporter assays, the results suggested that miRNA-124 was associated with lncRNA 1308. Furthermore, the expression of a disintegrin and a metalloproteinase 15 (ADAM 15) was downregulated in NSCLC cells when silencing of lncRNA 1308, the target of oncogenic miR-124, inhibits NSCLC cell proliferation and invasion. Conversely, the expression of ADAM 15 was significantly increased, when inhibiting the expression of miR-124, and alleviated cell invasion inhibition.

Conclusion

The results suggested that lncRNA 1308 may function as a competing endogenous RNA (ceRNA) for miR-124 to regulate cell invasion through the miR-124/ADAM 15 signaling pathway, indicating that lncRNA 1308 plays an important role in the disease progression of NSCLC.

A comprehensive competitive endogenous RNA network pinpoints key molecules in diabetic retinopathy

Diabetic retinopathy (DR) is a severe microvascular complication of diabetes and the primary cause of vision loss in diabetic patients. Previous research has revealed that long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) play pivotal roles in the pathogenesis of DR. However, the roles of lncRNA-miRNA-mRNA interactions in DR are poorly understood. In the present study, we aimed to compute a global triple network of competitive endogenous RNAs (ceRNAs) in order to pinpoint essential molecules. We found that there were 802 nodes (121 lncRNA nodes, 17 miRNA nodes, and 664 mRNA nodes) and 949 edges in the ceRNA network. Further functional analysis suggested that some molecules were specifically related to DR. Surprisingly, these molecules were involved in visual perception, eye development, and lens development in camera-type eye. In summary, our study highlighted specific lncRNAs and miRNAs related to the pathogenesis of DR, which might be used as potential diagnostic biomarkers and therapeutic targets for DR.

Altered expression of circular RNAs in human placental chorionic plate-derived mesenchymal stem cells pretreated with hypoxia

BACKGROUND

Hypoxic preconditioning alters the biological properties of mesenchymal stem cells (MSCs). It is not known whether this process has an effect on circular RNAs (circRNAs) in MSCs.

METHODS

Human placental chorionic plate-derived MSCs (hpcpMSCs) isolated from the same placentae were classed into two groups: hypoxic pretreated (hypoxia) group and normally cultured (normoxia) group. The comparative circRNA microarray analysis was used to determine circRNAs expression and verified by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) in the two groups.

RESULTS

One hundred and two differentially expressed circRNAs in the hypoxia group were found compared to that in the normoxia group (fold change >1.5-fold and P < 0.05). The expression levels of circRNAs by qRT-PCR were consistent with those evaluated by microarray analysis. Gene ontology (GO) analysis showed that the putative function of their target genes for those differentially expressed circRNAs was primarily involved in cell development and its differentiation and regulation. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that transcriptional misregulation in cancer and mitogen-activated protein kinase (MAPK) signaling pathway were the most significant. MAPK signaling pathway was found to be the core regulatory pathway triggered by hypoxia.

CONCLUSIONS

The results indicate that the altered expression of specific circRNAs in MSCs is associated with hypoxic preconditioning. This finding provides further exploration of underlying mechanisms of the characteristic changes of MSCs with hypoxic preconditioning.

Long non-coding RNA SNHG20 promotes the tumorigenesis of oral squamous cell carcinoma via targeting miR-197/LIN28 axis

Long non‐coding RNA (lncRNA) has been verified to participate in the tumour regulation, including oral squamous cell carcinoma (OSCC). Nevertheless, the role of lncRNA SNHG20 on OSCC still remains elusive. Here, we investigate the physiopathologic functions of lncRNA SNHG20 in OSCC tumorigenesis and explore its potential mechanism. LncRNA SNHG20 was up‐regulated in OSCC tissue compared with adjacent non‐tumour tissue. Meanwhile, SNHG20 was overexpressed in cancer stem‐like cells. In vitro and in vivo, loss‐of‐function experiments showed that lncRNA SNHG20 knockdown inhibited proliferative ability, mammosphere‐forming ability, ALDH1 expression, stem factors (LIN28, Nanog, Oct4, SOX2) and tumour growth. Bioinformatics and luciferase reporter assay revealed that miR‐197 targeted the 3′‐untranslated regions of SNHG20 and LIN28 by complementary binding. Validation experiments confirmed the associated functions of SNHG20/miR‐197/LIN28 axis on OSCC proliferation and stemness. In summary, our results reveal the important function of SNHG20/miR‐197/LIN28 axis in the oncogenesis and stemness of OSCC, suggesting the vital role of SNHG20 in OSCC tumorigenesis.

Epigenetic regulation of MAGE family in human cancer progression-DNA methylation, histone modification, and non-coding RNAs

The melanoma antigen gene (MAGE) proteins are a group of highly conserved family members that contain a common MAGE homology domain. Type I MAGEs are relevant cancer-testis antigens (CTAs), and originally considered as attractive targets for cancer immunotherapy due to their typically high expression in tumor tissues but restricted expression in normal adult tissues. Here, we reviewed the recent discoveries and ideas that illustrate the biological functions of MAGE family in cancer progression. Furthermore, we also highlighted the current understanding of the epigenetic mechanism of MAGE family expression in human cancers.

lncRNA-ATB functions as a competing endogenous RNA to promote YAP1 by sponging miR-590-5p in malignant melanoma

The critical long non‑coding RNAs (lncRNAs) involved in the carcinogenesis and progression of malignant melanoma (MM) have not been fully investigated. In the present study, it was identified that lncRNA activated by transforming growth factor‑β (lncRNA‑ATB) was upregulated in MM tissues and cells compared with benign nevus cells and human melanocytes, via comparative lncRNA screening from Gene Expression Omnibus datasets and reverse transcription‑quantitative polymerase chain reaction analysis. Furthermore, lncRNA‑ATB promoted the cell proliferation, cell migration, and cell invasion of MM cells in vitro, and tumor growth in vivo. It was additionally identified that lncRNA‑ATB attenuated cell cycle arrest and inhibited cellular apoptosis in MM cells. Finally, it was demonstrated that lncRNA‑ATB functions as a competing endogenous RNA (ceRNA) to enhance Yes associated protein 1 expression by competitively sponging microRNA miR‑590‑5p in MM cells. In conclusion, the present study revealed the expression and roles of lncRNA‑ATB in MM, and indicated that lncRNA‑ATB functions as a ceRNA to promote MM proliferation and invasion by sponging miR‑590‑5p.

Network-Based Approaches to Explore Complex Biological Systems towards Network Medicine

Network medicine relies on different types of networks: from the molecular level of protein–protein interactions to gene regulatory network and correlation studies of gene expression. Among network approaches based on the analysis of the topological properties of protein–protein interaction (PPI) networks, we discuss the widespread DIAMOnD (disease module detection) algorithm. Starting from the assumption that PPI networks can be viewed as maps where diseases can be identified with localized perturbation within a specific neighborhood (i.e., disease modules), DIAMOnD performs a systematic analysis of the human PPI network to uncover new disease-associated genes by exploiting the connectivity significance instead of connection density. The past few years have witnessed the increasing interest in understanding the molecular mechanism of post-transcriptional regulation with a special emphasis on non-coding RNAs since they are emerging as key regulators of many cellular processes in both physiological and pathological states. Recent findings show that coding genes are not the only targets that microRNAs interact with. In fact, there is a pool of different RNAs—including long non-coding RNAs (lncRNAs) —competing with each other to attract microRNAs for interactions, thus acting as competing endogenous RNAs (ceRNAs). The framework of regulatory networks provides a powerful tool to gather new insights into ceRNA regulatory mechanisms. Here, we describe a data-driven model recently developed to explore the lncRNA-associated ceRNA activity in breast invasive carcinoma. On the other hand, a very promising example of the co-expression network is the one implemented by the software SWIM (switch miner), which combines topological properties of correlation networks with gene expression data in order to identify a small pool of genes—called switch genes—critically associated with drastic changes in cell phenotype. Here, we describe SWIM tool along with its applications to cancer research and compare its predictions with DIAMOnD disease genes.

A comprehensive review of circRNA: from purification and identification to disease marker potential

Circular RNA (circRNA) is an endogenous noncoding RNA with a covalently closed cyclic structure. Based on their components, circRNAs are divided into exonic circRNAs, intronic circRNAs, and exon-intron circRNAs. CircRNAs have well-conserved sequences and often have high stability due to their resistance to exonucleases. Depending on their sequence, circRNAs are involved in different biological functions, including microRNA sponge activity, modulation of alternative splicing or transcription, interaction with RNA-binding proteins, and rolling translation, and are a derivative of pseudogenes. CircRNAs are involved in the development of a variety of pathological conditions, such as cardiovascular diseases, diabetes, neurological diseases, and cancer. Emerging evidence has shown that circRNAs are likely to be new potential clinical diagnostic markers or treatments for many diseases. Here we describe circRNA research methods and biological functions, and discuss the potential relationship between circRNAs and disease progression.

Diagnostic and prognostic relevance of serum miR-195 in pediatric acute myeloid leukemia

BACKGROUND

MicroRNA-195 acts as a tumor suppressor in a variety of cancers. However, its clinical significance in pediatric acute myeloid leukemia (AML) remains largely undefined.

OBJECTIVE

To investigate the diagnostic and prognostic relevance of miR-195 in this malignancy.

METHODS

Expression levels of miR-195 in peripheral blood and bone marrow samples of patients with pediatric AML and normal controls were detected by real-time quantitative PCR. Then, receiver-operating characteristic (ROC) curve analysis, Kaplan-Meier method, and Cox regression analysis were performed to evaluate the diagnostic and prognostic relevance of serum miR-195 in pediatric AML.

RESULTS

Compared to normal controls, the expression levels of miR-195 in both bone marrow and patients' sera were significantly decreased (both P< 0.001). In addition, serum miR-195 had an optimal diagnostic cut-off point (2.09) for pediatric AML with sensitivity of 68.87% and specificity of 96.23%. The area under the ROC curve (AUC) based on serum miR-195 was 0.910. Moreover, patients with low serum miR-195 level more often had French-American-British classification subtype M7 (P= 0.02), unfavorable karyotypes (P= 0.01), and shorter relapse-free and overall survivals (both P= 0.001) than those with high serum miR-195 level. Furthermore, the multivariate analysis identified serum miR-195 level as an independent prognostic factor for both relapse-free and overall survivals.

CONCLUSION

The findings of this study suggest that the aberrant expression of miR-195 may play crucial roles in the development and progression of pediatric AML patients. Serum miR-195 may serve as a promising marker for monitoring the occurrence of this disease and predicting the clinical outcome of patients.

HOXA11-AS promotes the growth and invasion of renal cancer by sponging miR-146b-5p to upregulate MMP16 expression

Recently, increasing studies showed that long noncoding RNAs (lncRNAs) play critical roles in tumor progression. However, the function and underlying mechanism of HOMEOBOX A11 antisense RNA (HOXA11-AS) on renal cancer remain unclear. In the current study, our data showed that the expression of HOXA11-AS was significantly upregulated in clear cell renal cell carcinoma (ccRCC) tissues and cell lines. High HOXA11-AS expression was associated with the advanced clinical stage, tumor stage, and lymph node metastasis. Function assays showed that HOXA11-AS inhibition significantly suppressed renal cancer cells growth, invasion, and ETM phenotype. In addition, underlying mechanism revealed that HOXA11-AS could act as a competing endogenous RNA (ceRNA) that repressed miR-146b-5p expression, which regulated its downstream target MMP16 in renal cancer. Taken together, our findings suggested that HOXA11-AS could promote renal cancer cells growth and invasion by modulating miR-146b-5p-MMP16 axis. Thus, our findings suggested that HOXA11-AS could serve as potential therapeutic target for the treatment of renal cancer.

A novel oncogenic role for urokinase receptor in leukemia cells: molecular sponge for oncosuppressor microRNAs

Urokinase receptor (uPAR) expression is up-regulated and represents a negative prognostic marker in most cancers. We previously reported that uPAR and CXCR4 can be regulated by common microRNAs in leukemia cells. Transcripts containing response elements for shared microRNAs in their 3’UTR may regulate their availability.

We investigated uPAR 3’UTR capability to recruit microRNAs, thus regulating the expression of their targets. uPAR 3’UTR transfection in KG1 leukemia cells up-regulates the expression of endogenous uPAR. Transfection of uPAR 3’UTR, inserted downstream a reporter gene, increases uPAR expression and simultaneously down-regulates the reporter gene expression. Transfection of uPAR 3’UTR also increases CXCR4 expression; accordingly, uPAR silencing induces down-regulation of CXCR4 expression, through a mechanism involving Dicer, the endoribonuclease required for microRNA maturation.

Transfection of uPAR 3’UTR also increases the expression of pro-tumoral factors and modulates cell adhesion and migration, consistently with the capability of uPAR3’UTR-recruited microRNAs to target several and different transcripts and, thus, functions.

Finally, we found 3’UTR-containing variants of uPAR transcript in U937 leukemia cells, which show higher levels of uPAR expression as compared to KG1 cells, in which these variants are not detected.

These results suggest that uPAR mRNA may recruit oncosuppressor microRNAs, allowing the expression of their targets.

HOXD-AS1/miR-130a sponge regulates glioma development by targeting E2F8

Glioma development is an extremely complex process with changes occurring in numerous genes. HOXD antisense growth-associated long noncoding RNA (HOXD-AS1), an important long noncoding RNA (lncRNA), is known to regulate metastasis-related gene expression in bladder cancer, ovarian cancer and neuroblastoma. Here, we elucidated the function and possible molecular mechanisms of lncRNA HOXD-AS1 in human glioma cells. Our results proved that HOXD-AS1 expression was upregulated in glioma tissues and in glioma cell lines. HOXD-AS1 overexpression promoted cell migration and invasion in vitro, whereas knockdown of HOXD-AS1 expression repressed these cellular processes. Mechanistic studies further revealed that HOXD-AS1 could compete with the transcription factor E2F8 to bind with miR-130a, thus affecting E2F8 expression. Additionally, reciprocal repression was observed between HOXD-AS1 and miR-130a, and miR-130a mediated the tumor-suppressive effects of HOXD-AS1 knockdown. Taken together, these results provide a comprehensive analysis of the role of HOXD-AS1 in glioma cells and offer important clues to understand the key roles of competing endogenous RNA (ceRNA) mechanisms in human glioma.

LncRNA n335586/miR-924/CKMT1A axis contributes to cell migration and invasion in hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is a leading cause of cancer death worldwide and chronic hepatitis B virus (HBV) infection is a major risk factor for HCC. Emerging evidences indicate that long noncoding RNAs (lncRNAs) play a pivotal role in HCC development, but its contribution to HBV-related HCC remains largely unclear. Differentially expressed lncRNAs in HBV-related HCC tissues were identified by deep sequencing in our previous study. The function of lncRNA n335586, one of most up-regulated lncRNAs in HBV-related HCC, was characterized in the present study. We found that the expression of n335586 was significantly increased in HBV positive HCC tissues and cells and was induced by HBV in vitro. Function study indicated that lncRNA n335586 remarkably promoted HCC cells migration, invasion and epithelial-mesenchymal transition (EMT) in vitro and metastasis in vivo. Further mechanistic studies showed lncRNA n335586 promoted HCC cells migration and invasion through facilitating the expression of its host gene CKMT1A by competitively binding miR-924. In conclusion, we demonstrated that the n335586/miR-924/CKMT1A axis contributes to HCC cell migration and invasion, which may be helpful for understanding of pathogenesis of HBV-related HCC.

Systematic analysis of lncRNAs, mRNAs, circRNAs and miRNAs in patients with postmenopausal osteoporosis

Osteoporosis (OP) is a disease characterized by bone loss, imbalance of bone metabolism and destruction of trabecular microstructure, and associated with menopause. Studies have shown that immune related lymphocytes are involved in bone metabolism. However, the molecular mechanisms hidden in the interaction of lymphocytes with OP need to be further studied. In the present study, we investigated the expression profiles and differences of lncRNAs, mRNAs, circRNAs and miRNAs in peripheral blood lymphocytes of patients with postmenopausal OP using Illumina-based complementary DNA (cDNA) deep sequencing (RNA-seq). 70 lncRNAs, 475 mRNAs, 260 circRNAs and 13 miRNAs were differentially expressed in patients with postmenopausal osteoporosis (OP group) compared with healthy controls (NC group). The functions of differentially expressed lncRNAs, circRNA, miRNA and potential targeting genes were predicted by Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Complex lncRNA-miRNA-mRNA and circRNA-miRNA-mRNA regulatory networks were constructed based on differentially expressed RNAs. Taken together, our study indicated that lncRNAs, mRNA, circRNAs and miRNA could associate with the occurrence of postmenopausal OP and may be as possible biomarkers and target genes in lymphocytes for OP.

The lncRNA myocardial infarction associated transcript-centric competing endogenous RNA network in non-small-cell lung cancer

Background

The leading cause of death for cancer is lung cancer, of which the majority subtype is non-small cell lung cancer (NSCLC). Recent studies have shown long non-coding RNAs are transcribed and contribute to cancer. Previous study has shown that a few single nucleotide polymorphisms (SNPs) in myocardial infarction associated transcript (MIAT) were associated with some diseases or function as competing endogenous RNA (ceRNA) in some cancer.

Patients and methods

We performed bioinformatic methods for analyzing RNA-seq and miRNA-seq data of NSCLC from The Cancer Genome Atlas database. 1352 NSCLC patients and 1320 cancer-free controls for genotyping, and dual luciferase reporter assay, real-time PCR are performed in A549 and H1975 lung cancer cell lines. Results are analyzed by SPSS v16.0.

Results

In the present study, we focus on the role of over-expression MIAT in NSCLC. We confirmed that rs1061451 T>C (allele odds ratio = 0.22; P < 0.01) was associated with NSCLC. Furthermore, we constructed MIAT-centric ceRNA network, and three mRNAs (MYO1B, SGK1 and WNT9A) was identified as targets by MIAT via miR-133a-5p.

Conclusion

C-containing genotypes of MIAT rs1061451 were protective factor of NSCLC, and MIAT, which may act as ceRNA via miR-133a-5p, modulated MYO1B, SGK1 and WNT9A expression level.

Quaking promotes the odontoblastic differentiation of human dental pulp stem cells

Odontoblastic differentiation of human dental pulp stem cells (hDPSCs) is essential for the formation of reparative dentin after dental caries or injury. Our previous studies have demonstrated that krüppel-like factor 4 (KLF4) is a critical transcription factor that promotes the odontoblastic differentiation of hDPSCs. Analysis of the microRNA binding sites within the 3'-UTR of KLF4 revealed that QKI, an RNA-binding protein, shared the most microRNAs with KLF4, presumably served as a "competent endogenous RNA (ceRNA)" with KLF4. Thus, we hypothesized QKI could also promote odontoblastic differentiation. In this study, we found QKI was up-regulated during mouse odontoblast differentiation in vivo and hDPSCs odontoblastic differentiation in vitro. Overexpression or knockdown of QKI in hDPSCs led to the increase or decrease of odontoblast marker genes' expressions, indicating its positive role in odontoblastic differentiation. We further validated that QKI served as a key ceRNA of KLF4 via interaction of the shared miRNAs in hDPSCs. Last, we found that, as an RNA binding protein, QKI protein could bind to, and stabilize dentin sialophosphoprotein (DSPP) mRNA, resulting in the augmented accumulation of DSP protein. Taken together, our study indicates that QKI promotes the odontoblastic differentiation of hDPSCs by acting as a ceRNA of KLF4 and as a binding protein of DSPP mRNA to stabilize its level. These two mechanisms of QKI will together positively regulate the downstream pathways and hence potentiate odontoblastic differentiation.

LncRNA RSU1P2 contributes to tumorigenesis by acting as a ceRNA against let-7a in cervical cancer cells

Long non-coding RNAs (lncRNAs) can regulate gene expression at different levels and are widely participate in various physiological and pathological processes. Emerging evidences suggests that a number of differentially expressed lncRNAs are involved in tumorigenesis. However, the function and expression regulation of a vast majority of these unique RNAs is little known. Here, we found that the lncRNA Ras suppressor protein 1 pseudogene 2 (RSU1P2) is upregulateded in cervical cancer tissues and has a tumour-promoting role. We revealed that RSU1P2 acts as a competitive endogenous RNA (ceRNA) through regulating the expression of IGF1R, N-myc and EphA4. The mechanism of this regulation is via competition for the shared microRNA let-7a. This competition promotes the malignant phenotype of cervical carcinoma cells. The transcription factor N-myc forms a positive feedback loop with RSU1P2 by in turn activating its expression, thereby enhancing its oncogenic capacity. Hence, cancer-selective targeting of RSU1P2 could have strong benefits.

The long noncoding RNA linc-NeD125 controls the expression of medulloblastoma driver genes by microRNA sponge activity

Long noncoding RNAs (lncRNAs) are major regulators of physiological and disease-related gene expression, particularly in the central nervous system. Dysregulated lncRNA expression has been documented in several human cancers, and their tissue-specificity makes them attractive candidates as diagnostic/prognostic biomarkers and/or therapeutic agents. Here we show that linc-NeD125, which we previously characterized as a neuronal-induced lncRNA, is significantly overexpressed in Group 4 medulloblastomas (G4 MBs), the largest and least well characterized molecular MB subgroup. Mechanistically, linc-NeD125 is able to recruit the miRNA-induced silencing complex (miRISC) and to directly bind the microRNAs miR-19a-3p, miR-19b-3p and miR-106a-5p. Functionally, linc-NeD125 acts as a competing endogenous RNA (ceRNA) that, sequestering the three miRNAs, leads to de-repression of their targets CDK6, MYCN, SNCAIP, and KDM6A, which are major driver genes of G4 MB. Accordingly, linc-NeD125 downregulation reduces G4 cell proliferation. Moreover, we also provide evidence that linc-NeD125 ectopic expression in the aggressive Group 3 MB cells attenuates their proliferation, migration and invasion.This study unveils the first lncRNA-based ceRNA network in central nervous system tumours and provides a novel molecular circuit underlying the enigmatic Group 4 medulloblastoma.

Long non-coding RNA CTA sensitizes osteosarcoma cells to doxorubicin through inhibition of autophagy

Recently, several long non-coding RNAs (lncRNAs) have been implicated in osteosarcoma (OS). However, the regulatory roles of lncRNAs in chemotherapy resistance of OS still remain unclear. This study aimed to screen a novel lncRNA that contributes to chemotherapeutic resistance of OS, and to explore the underlying mechanisms. Our data showed that lncRNA CTA was markedly downregulated in OS tissues compared to their matched non-tumor tissues, and low expression of lncRNA CTA was significantly associated with the advanced clinical stage and tumor size. In addition, OS patients with low lncRNA CTA levels showed a worse prognosis when compared with those with high expression of lncRNA CTA. Furthermore, we report that lncRNA CTA has an inverse relationship with miR-210 expression in OS tissues. LncRNA CTA could be activated by doxorubicin (DOX), and could promote OS cell apoptosis by competitively binding miR-210, while inhibit cell autophagy. On the other hand, lncRNA CTA was downregulated in DOX-resistant OS cells. Overexpression of lncRNA CTA reduced autophagy and subsequently overcame DOX resistance of OS in vitro and in vivo. Therefore, we demonstrate that lncRNA CTA is an essential regulator in DOX-induced OS cell apoptosis, and the lncRNA CTA-miR-210 axis plays an important role in reducing OS chemoresistance.

LncRNA DANCR functions as a competing endogenous RNA to regulate RAB1A expression by sponging miR-634 in glioma

Long noncoding RNA (lncRNA) differentiation antagonizing nonprotein coding RNA (DANCR) plays important regulatory roles in many solid tumors. However, the effect of DANCR in glioma progression and underlying molecular mechanisms were not entirely explored. In the present study, we determined the expression of DANCR in glioma tissues and cell lines using qRT-PCR and further defined the biological functions. Furthermore, we used luciferase reporter assay, Western blot, and RNA immunoprecipitation (RIP) to explore the underlying mechanism. Our results showed that DANCR was significantly up-regulated in glioma tissues and cell lines (U251, U118, LN229, and U87MG). High DANCR expression was correlated with advanced tumor grade. Inhibition of DANCR suppressed the glioma cells proliferation and induced cells arrested in the G0/G1 phase. In addition, we verified that DANCR could directly interact with miR-634 in glioma cells and this interaction resulted in the inhibition of downstream of RAB1A expression. The present study demonstrated that DANCR/miR-634/RAB1A axis plays crucial roles in the progression of glioma, and DANCR might potentially serve as a therapeutic target for the treatment of glioma patients.

The long non-coding RNA SUMO1P3 facilitates breast cancer progression by negatively regulating miR-320a

Although the long non-coding RNA (lncRNA) SUMO1P3, small ubiquitin-like modifier 1 pseudogene 3, has been shown to play a role in human cancer, the biological function and mechanism of SUMO1P3 in breast cancer remained unclear. In this study, we showed that SUMO1P3 expression was higher in breast cancer tissues when compared to adjacent normal tissues and we found that high levels of SUMO1P3 expression associated significantly with tumor progression and poor survival of breast cancer patients. Moreover, we found that knockdown of SUMO1P3 suppressed proliferation, migration, and invasion of breast cancer cells. Bioinformatics analysis and luciferase reporter assays confirmed that SUMO1P3 binds to miR-320a, which has been identified as a tumor suppressor in various cancers, including breast cancer. We also confirmed that the tumor-promoting effects of SUMO1P3 in breast cancer are partly mediated by negative regulation of miR-320a. Our data indicates that SUMO1P3 functions as an oncogenic lncRNA in breast cancer and may serve as a novel diagnostic and biological target for breast cancer diagnosis and treatment.

Long non-coding RNA LINC00152 promotes cell proliferation, metastasis, and confers 5-FU resistance in colorectal cancer by inhibiting miR-139-5p

Long intergenic non-coding RNA 152 (LINC00152) is a recently identified tumor-promoting long non-coding RNA. However, the biological functions of LINC00152 in colorectal cancer (CRC) remain unclear and require further research. The aim of the present study is to explore the roles of LINC00152 in cellular function and its possible molecular mechanism. In this study, we discovered that LINC00152 was overexpressed in CRC tissues and negatively related to the survival time of CRC patients. Functional analyses revealed that LINC00152 could promote cell proliferation. Furthermore, LINC00152 could increase the resistance of CRC cells to 5-fluorouracil (5-FU) by suppressing apoptosis. We also discovered that LINC00152 could enhance cell migration and invasion. Mechanistic studies demonstrated that LINC00152 could regulate the expression of NOTCH1 through sponging miR-139-5p and inhibiting its activity from promoting CRC progression and development. Altogether, our work points out a novel LINC00152/miR-139-5p/NOTCH1 regulatory axis in CRC progression and development.

Long noncoding RNA lncBRM facilitates the proliferation, migration and invasion of ovarian cancer cells via upregulation of Sox4

Ovarian cancer (OC) is one of the most fatal gynecological cancer in women worldwide. Long noncoding RNA (lncRNA) lncBRM was found to be associated with the progression and prognosis of hepatocellular carcinoma (HCC). However, the expression level, clinical significance and functions in OC tumorigenesis and progression remain unclear. Our present research demonstrated that lncBRM expression was significantly increased in OC tissues. Upregulation of lncBRM expression was correlated with histological grade, FIGO stages, lymph node metastasis and poor prognosis of patients with OC. Functional assays showed that lncBRM positively regulated cell proliferation, migration and invasion in OC. Moreover, lncBRM upregulated Sox4 by competitively binding miR-204. Together, lncBRM functions as an oncogene in OC and can be a promising therapeutic target for OC treatment.

The crosstalk between lncRNA and microRNA in cancer metastasis: orchestrating the epithelial-mesenchymal plasticity

Noncoding RNAs (ncRNAs) have been demonstrated to closely associate with gene regulation and encompass the well-known microRNAs (miRNAs), as well as the most recently acknowledged long noncoding RNAs (lncRNAs). Current evidence indicates that lncRNAs can interact with miRNAs and these interactions play crucial roles in cancer metastasis, through regulating critical events especially the epithelial-mesenchymal transition (EMT). This review summarizes the types of lncRNA-miRNA crosstalk identified to-date and discusses their influence on the epithelial-mesenchymal plasticity and clinical metastatic implication.

The role of miR-17-92 in the miRegulatory landscape of Ewing sarcoma

MicroRNAs serve to fine-tune gene expression and play an important regulatory role in tissue specific gene networks. The identification and validation of miRNA target genes in a tissue still poses a significant problem since the presence of a seed sequence in the 3′UTR of an mRNA and its expression modulation upon ectopic expression of the miRNA do not reliably predict regulation under physiological conditions. The chimeric oncoprotein EWS-FLI1 is the driving pathogenic force in Ewing sarcoma. MiR-17-92, one of the most potent oncogenic miRNAs, was recently reported to be among the top EWS-FLI1 activated miRNAs. Using a combination of AGO2 pull-down experiments by PAR-CLIP (Photoactivatable-Ribonucleoside-Enhanced Crosslinking and Immunoprecipitation) and of RNAseq upon miRNA depletion by ectopic sponge expression, we aimed to identify the targetome of miR-17-92 in Ewing sarcoma. Intersecting both datasets we found an enrichment of PAR-CLIP hits for members of the miR-17-92 cluster in the 3′UTRs of genes up-regulated in response to mir-17-92 specific sponge expression. Strikingly, approximately a quarter of these genes annotate to the TGFB/BMP pathway, the majority mapping downstream of SMAD signaling. Testing for SMAD phosphorylation, we identify quiet but activatable TGFB signaling and cell autonomous activity of the BMP pathway resulting in the activation of the stemness regulatory transcriptional repressors ID1 and ID3. Taken together, our findings shed light on the complex miRegulatory landscape of Ewing Sarcoma pointing miR-17-92 as a key node connected to TGFB/BMP pathway.

Noncoding RNA in drug resistant sarcoma

Sarcomas are a group of malignant tumors that arise from mesenchymal origin. Despite significant development of multidisciplinary treatments for sarcoma, survival rates have reached a plateau. Chemotherapy has been extensively used for sarcoma treatment; however, the development of drug resistance is a major obstacle limiting the success of many anticancer agents. Sarcoma biology has traditionally focused on genomic and epigenomic deregulation of protein-coding genes to identify the therapeutic potential for reversing drug resistance. New and more creative approaches have found the involvement of noncoding RNAs, including microRNAs and long noncoding RNAs in drug resistant sarcoma. In this review, we discuss the current knowledge of noncoding RNAs characteristics and the regulated genes involved in drug resistant sarcoma, and focus on their therapeutic potential in the future.

A positive feedback loop of long noncoding RNA CCAT2 and FOXM1 promotes hepatocellular carcinoma growth

Hepatocellular carcinoma (HCC) is one of the most common malignancies around the world. Long noncoding RNAs (lncRNAs) are greater than 200 nucleotides without protein-coding potential and play critical roles in tumorigenesis, cell differentiation, and cancer metastasis. Colon cancer-associated transcript 2 (CCAT2), a newly identified lncRNA, was shown to be dysregulated in cancers. However, the functional role of CCAT2 in HCC remains questionable. In the present study, we found a significant upregulation of CCAT2 in HCC tissues as compared to non-tumor tissues. Functional assays showed that CCAT2 promotes cell growth in vivo and in vitro. In addition, we found a positive feedback loop between CCAT2 and FOXM1. CCAT2 upregulates FOXM1 expression through interaction with, and suppression of, miR-34a, and FOXM1 activates CCAT2 transcription. We evaluated the therapeutic potential of ultrasound-targeted microbubble destruction (UTMD)-mediated siRNA delivery to specifically target CCAT2. UTMD-mediated siCCAT2 delivery significantly suppressed tumor growth in vivo. Thus, CCAT2-FOXM1 may be a novel target for the treatment of HCC.

microRNA inhibitors: Natural and artificial sequestration of microRNA

MicroRNA (miRNAs) is post-transcriptional regulator of mRNA. However, the prevalence and activity of miRNA are regulated by other regulators. miRNA inhibitors are natural or artificial RNA transcripts that sequestrate miRNAs and decrease or even eliminate miRNA activity. Competing endogenous RNAs (ceRNAs) are natural and intracellular miRNA inhibitors that compete to bind to shared miRNA recognition elements (MREs) to decrease microRNA availability and relieve the repression of target RNAs. In recent years, studies have revealed that ceRNA crosstalk is involved in many pathophysiological processes and adds a new dimension to miRNA regulation. Artificial miRNA inhibitors are RNA transcripts that are synthesized via chemical and genetic methods. Artificial miRNA inhibitors can be used in miRNA loss-of-function research and gene therapies for certain diseases. In this review, we summarize the recent advances in the two different types of miRNA inhibitors.

LAMC1 mRNA promotes malignancy of hepatocellular carcinoma cells by competing for MicroRNA-124 binding with CD151

Specific RNAs can function as sinks for endogenous miRNAs, known as competing endogenous RNAs (ceRNAs). Here, we confirm a miR-124 mediated ceRNA crosstalk between LAMC1 and CD151 in hepatocellular carcinoma (HCC). miR-124 negatively regulates LAMC1 expression through two miRNA binding sites within its 3' untranslated region (3'UTR) and suppresses migration and invasion of HCC cells through regulating LAMC1. The wild type LAMC1 miRNA response elements (MREs) facilitate expression of CD151, and this regulation is miR-124 dependent. In clinical hepatic tissues, LAMC1 and CD151 mRNAs exhibit positive correlation. Importantly, LAMC1 MREs promote HCC malignancy by absorbing miR-124 and by assisting CD151 expression. We conclude that LAMC1 mRNA acts as a trans regulator to stimulate CD151 expression by competing for miR-124 binding in HCC cells. © 2017 IUBMB Life, 69(8):595-605, 2017.

LncRNA MEG3 inhibits cell epithelial-mesenchymal transition by sponging miR-421 targeting E-cadherin in breast cancer

BACKGROUND

MEG3, a lncRNA, has been verified in several tumors to function as tumor suppressors including breast cancer development and progression, however, the expression pattern and underlying mechanisms of MEG3 involved in breast cancer progression is still need to be further explored.

METHODS

The expression of MEG3 was confirmed in 90 cases of breast cancer tissues compared to adjacent normal tissues by quantitative real-time polymerase chain reaction (qRT-PCR) analysis. The association between clinicopathological factors and MEG3 expression was evaluated by chi-square test. Kaplan-Meier curve and log rank test was performed to assess disease-free survival (DFS) and overall survival (OS) time in patients. CCK8 and transwell invasion assays were used to assess cell proliferation and invasion capacity. Luciferase report assay and RNA pull down assay were used to detect the association between miR-421 and MEG3 in breast cancer.

RESULTS

In the study, we demonstrated that the expression of MEG3 was significantly down-regulated in breast cancer tissues compared to adjacent normal tissues. Reducing MEG3 expression was significantly associated with TNM stage and lymph nodes metastasis in patients. Survival analysis showed that lower MEG3 predicted a poor DFS and OS for patients. In vitro, we showed that up-regulated MEG3 inhibited cell proliferation and cell invasion capacities. We further revealed that endogenous miR-421 expression was negatively regulated by MEG3 in breast cancer cells and MEG3 regulated E-cadherin expression by sponging to miR-421 in breast cancer cells.

CONCLUSIONS

Our results showed that MEG3/miR-421/E-cadherin regulatory axis may be a novel therapeutic target for breast cancer.

SNHG1 lncRNA negatively regulates miR-199a-3p to enhance CDK7 expression and promote cell proliferation in prostate cancer

Long noncoding RNAs (lncRNAs) have been reported to play vital roles in the development of human cancers, but our understandings of most lncRNAs in cancers are still limited. Recently, accumlating evidences have showed that many RNA transcripts could function as competing endogenous RNAs (ceRNAs) by competitively binding common microRNAs. In this study, we demonstrated that a lncRNA, Small Nucleolar RNA Host Gene 1 (SNHG1), as a ceRNA for miR-199a-3p, played a critical role in prostate cancer cell proliferation. We found that SNHG1 was aberrantly up-regulated in prostate carcinoma tissues; while, miR-199a-3p was abnormally down-regulated. The level of SNHG1 in prostate cancer was significantly negatively correlated with that of miR-199a-3p. Our data indicated that SNHG1 could interact with miR-199a-3p and inhibit the activity of miR-199a-3p in prostate cancer cells. In addition, miR-199a-3p could target the 3' UTR of CDK7 and suppress CDK7 expression. More importantly, SNHG1 increased CDK7 expression by competitively binding miR-199a-3p, and then promoted cell proliferation and cell cycle progression in prostate cancer. Taken together, these findings elucidated a novel mechanism of prostate cancer progression. Thus, SNHG1 might serve as a potential target for prostate cancer therapies.

Potentials of Long Noncoding RNAs (LncRNAs) in Sarcoma: From Biomarkers to Therapeutic Targets

Sarcoma includes some of the most heterogeneous tumors, which make the diagnosis, prognosis and treatment of these rare yet diverse neoplasms especially challenging. Long noncoding RNAs (lncRNAs) are important regulators of cancer initiation and progression, which implies their potential as neoteric prognostic and diagnostic markers in cancer, including sarcoma. A relationship between lncRNAs and sarcoma pathogenesis and progression is emerging. Recent studies demonstrate that lncRNAs influence sarcoma cell proliferation, metastasis, and drug resistance. Additionally, lncRNA expression profiles are predictive of sarcoma prognosis. In this review, we summarize contemporary advances in the research of lncRNA biogenesis and functions in sarcoma. We also highlight the potential for lncRNAs to become innovative diagnostic and prognostic biomarkers as well as therapeutic targets in sarcoma.

Noncoding RNAs in the development, diagnosis, and prognosis of colorectal cancer

More than 90% of the human genome is actively transcribed, but less than 2% of the total genome encodes protein-coding RNA, and thus, noncoding RNA (ncRNA) is a major component of the human transcriptome. Recently, ncRNA was demonstrated to play important roles in multiple biological processes by directly or indirectly interfering with gene expression, and the dysregulation of ncRNA is associated with a variety of diseases, including cancer. In this review, we summarize the function and mechanism of miRNA, long intergenic ncRNA, and some other types of ncRNAs, such as small nucleolar RNA, circular ncRNA, pseudogene RNA, and even protein-coding mRNA, in the progression of colorectal cancer (CRC). We also presented their clinical application in the diagnosis and prognosis of CRC. The summary of the current state of ncRNA in CRC will contribute to our understanding of the complex processes of CRC initiation and development and will help in the discovery of novel biomarkers and therapeutic targets for CRC diagnosis and treatment.