Growth arrest in human T-cells is controlled by the non-coding RNA growth-arrest-specific transcript 5 (GAS5)

The regulatory network among CircHIPK3, LncGAS5, and miR-495 promotes Th2 differentiation in allergic rhinitis

Allergic rhinitis (AR) is a common allergic disease which is characterized by the promotion of Th2 differentiation of CD4⁺ T cells. However, the mechanisms underlying Th2 differentiation remain unclear. Non-coding RNAs play a critical role in Th2 differentiation, whereas few studies have revealed the interactions among long non-coding RNAs, circular RNAs, and microRNAs. In this study, the differential expressions of several circRNAs and lncRNAs were compared in nasal mucosa samples of AR patients and mice with experimentally induced AR as compared to healthy controls. The results showed that the highly expressed CircHIPK3 and LncGAS5 promoted Th2 differentiation of ovalbumin-induced CD4⁺ T cells and aggravated nasal symptoms of AR mice. We also found that CircHIPK3 and LncGAS5 induced the upregulation of Th2 cell-specific transcript factor GATA-3 via modulating their common target miR-495. Meanwhile, the intranasal administration of CircHIPK3 or LncGAS5 knockdown lentivirus decreased nasal symptoms of AR mice. In conclusion, our findings indicated that the interactions among CircHIPK3, LncGAS5, and miR-495 play a critical role in the regulation of Th2 differentiation in AR.

The glucocorticoid receptor DNA-binding domain recognizes RNA hairpin structures with high affinity

The glucocorticoid receptor (GR) binds the noncoding RNA Gas5 via its DNA-binding domain (DBD) with functional implications in pro-apoptosis signaling. Here, we report a comprehensive in vitro binding study where we have determined that GR-DBD is a robust structure-specific RNA-binding domain. GR-DBD binds to a diverse range of RNA hairpin motifs, both synthetic and biologically derived, with apparent mid-nanomolar affinity while discriminating against uniform dsRNA. As opposed to dimeric recognition of dsDNA, GR-DBD binds to RNA as a monomer and confers high affinity primarily through electrostatic contacts. GR-DBD adopts a discrete RNA-bound state, as assessed by NMR, distinct from both free and DNA-bound. NMR and alanine mutagenesis suggest a heightened involvement of the C-terminal α-helix of the GR-DBD in RNA-binding. RNA competes for binding with dsDNA and occurs in a similar affinity range as dimer binding to the canonical DNA element. Given the prevalence of RNA hairpins within the transcriptome, our findings strongly suggest that many RNAs have potential to impact GR biology.

Comprehensive analysis of differentially expressed lncRNAs as diagnostic and prognostic markers for colorectal cancer

Colorectal cancer (CRC) is the third most common type of cancer worldwide. Recent studies had revealed the important roles of long non-coding RNAs (lncRNAs) in a variety of human cancers, including CRC. However, the molecular mechanisms associated with CRC remain largely undetermined. In the current study, the GSE21510 dataset was analyzed to identify differentially expressed mRNAs and lncRNAs in CRC samples. The Database for Annotation, Visualization and Integrated Discovery was used to perform Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway bioinformatics analysis. Furthermore, protein-protein interaction networks were constructed to reveal interactions among differentially expressed proteins. Kaplan-Meier analysis was subsequently performed to determine the association between key lncRNA expression and the overall survival of patients with CRC. A total of 107 upregulated lncRNAs and 43 downregulated lncRNAs were identified in CRC. A lncRNA mediated co-expression network was also constructed in CRC. Bioinformatics analysis indicated that lncRNAs were associated with a series of biological processes, including 'xenobiotic glucuronidation', 'rRNA processing', 'sister chromatid cohesion', 'cell proliferation', 'mitotic nuclear division' and 'cell cycle regulation'. Furthermore, a higher expression of small nucleolar RNA host gene 17, tetratricopeptide repeat domain 2B-antisense RNA (AS) 1, erythrocyte membrane protein band 4.1 like 4A-AS2, deleted in lymphocytic leukemia 2, and a lower expression of muscle blind like splicing regulator 1-AS1 and LOC389332 were associated with shorter overall survival time in CRC samples. The present study provides useful information that can be used in the identification of novel biomarkers for CRC.

Long non-coding RNA GAS5 acts as proliferation "brakes" in CD133+ cells responsible for tumor recurrence

Presence of quiescent, therapy evasive population often described as cancer stem cells (CSC) or tumor initiating cells (TIC) is often attributed to extreme metastasis and tumor recurrence. This population is typically enriched in a tumor as a result of microenvironment or chemotherapy induced stress. The TIC population adapts to this stress by turning on cell cycle arrest programs that is a “fail-safe” mechanism to prevent expansion of malignant cells to prevent further injury. Upon removal of the “stress” conditions, these cells restart their cell cycle and regain their proliferative nature thereby resulting in tumor relapse. Growth Arrest Specific 5 (GAS5) is a long-non-coding RNA that plays a vital role in this process. In pancreatic cancer, CD133+ population is a typical representation of the TIC population that is responsible for tumor relapse. In this study, we show for the first time that emergence of CD133+ population coincides with upregulation of GAS5, that reprograms the cell cycle to slow proliferation by inhibiting GR mediated cell cycle control. The CD133+ population further routed metabolites like glucose to shunt pathways like pentose phosphate pathway, that were predominantly biosynthetic in spite of being quiescent in nature but did not use it immediately for nucleic acid synthesis. Upon inhibiting GAS5, these cells were released from their growth arrest and restarted the nucleic acid synthesis and proliferation. Our study thus showed that GAS5 acts as a molecular switch for regulating quiescence and growth arrest in CD133+ population, that is responsible for aggressive biology of pancreatic tumors.

Long noncoding RNAs in cancer: From discovery to therapeutic targets

Long noncoding RNAs (lncRNAs) have recently gained considerable attention as key players in biological regulation; however, the mechanisms by which lncRNAs govern various disease processes remain mysterious and are just beginning to be understood. The ease of next-generation sequencing technologies has led to an explosion of genomic information, especially for the lncRNA class of noncoding RNAs. LncRNAs exhibit the characteristics of mRNAs, such as polyadenylation, 5' methyl capping, RNA polymerase II-dependent transcription, and splicing. These transcripts comprise more than 200 nucleotides (nt) and are not translated into proteins. Directed interrogation of annotated lncRNAs from RNA-Seq datasets has revealed dramatic differences in their expression, largely driven by alterations in transcription, the cell cycle, and RNA metabolism. The fact that lncRNAs are expressed cell- and tissue-specifically makes them excellent biomarkers for ongoing biological events. Notably, lncRNAs are differentially expressed in several cancers and show a distinct association with clinical outcomes. Novel methods and strategies are being developed to study lncRNA function and will provide researchers with the tools and opportunities to develop lncRNA-based therapeutics for cancer.

Long non-coding RNAs in diseases related to inflammation and immunity

Long non-coding RNAs (lncRNAs) have been key regulators of gene expression in innate and adaptive immunity. Although lncRNAs have been reported to be associated with some diseases, its expression and function in diseases related to inflammation and immunity are still unknown. We reviewed how lncRNA regulated transcription and controlled the function and balance of the cells in the immune response. In addition, we discussed the impacts and challenges of lncRNAs on immunity in diseases.

Isosteviol Sodium Protects against Ischemic Stroke by Modulating Microglia/Macrophage Polarization via Disruption of GAS5/miR-146a-5p sponge

Recent studies have shown that transforming microglia phenotype from pro-inflammation of M1 phenotype to anti-inflammation and tissue-repairing M2 phenotype may be an effective therapeutic strategy for preventing ischemic stroke brain injury. Isosteviol Sodium (STV-Na) has shown promise as a neuroprotective agent in cerebral ischemia model, although its effect on microglial polarization and chronic recovery after stroke is not clear. Here, we demonstrated that STV-Na treatment significantly reduced cerebral ischemic damage at both acute and chronic time points. STV-Na has a profound regulatory effect on microglia response after stroke. It can promote M2 polarization and inhibit microglia-mediated inflammation (M1) response following stroke in vivo and in vitro. Furthermore, we also found that Growth Arrest-Specific 5 (GAS5) altered OGD/R-induced microglial activation by increasing Notch1 expression via miR-146a-5p, the mRNA level of GAS5 and the protein level of Notch1 in vivo and in vitro, were discovered that both downgraded with STV-Na. Taken together, the present study demonstrated that STV-Na exerted neuroprotective effects by modulating microglia/macrophage polarization in ischemic stroke via the GAS5/miR-146a-5p sponge. These findings provide new evidence that targeting STV-Na could be a treatment for the prevention of stroke-related brain damage.

Genome‑wide investigation of the clinical implications and molecular mechanism of long noncoding RNA LINC00668 and protein‑coding genes in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the leading causes of tumor‑related mortalities worldwide. Long noncoding RNAs have been reported to be associated with tumor initiation, progression and prognosis. The present study aimed to explore the association between long noncoding RNA LINC00668 and its co‑expression correlated protein‑coding genes (PCGs) in HCC. Data of 370 HCC patients from The Cancer Genome Atlas database were used for analysis. LINC00668 and its top 10 PCGs were selected to determine their diagnostic and prognostic value. Molecular mechanisms were explored to identify metabolic processes that LINC00668 and its PCGs are involved in. Prognosis‑related clinical factors and PCGs were used to construct a nomogram for predicting prognosis in HCC. A Connectivity Map was constructed to identify candidate target drugs for HCC. The top 10 PCGs identified were: Pyrimidineregic receptor P2Y4 (P2RY4), signal peptidase complex subunit 2 (SPCS2), family with sequence similarity 86 member C1 (FAM86C1), tudor domain containing 5 (TDRD5), ferritin light chain (FTL), stratifin (SFN), nucleolar complex associated 2 homolog (NOC2L), peroxiredoxin 1 (PRDX1), cancer/testis antigen 2 CTAG2 and leucine zipper and CTNNBIP1 domain containing (LZIC). FAM86C1, CTAG2 and SFN had significant diagnostic value for HCC (total area under the curve ≥0.7, P≤0.05); LINC00668, FAM86C1, TDRD5, FTL and SFN were of significant prognostic value for HCC (all P≤0.05). Investigation into the molecular mechanism indicated that LINC00668 affects cell division, cell cycle, mitotic nuclear division, and drug metabolism cytochrome P450 (all P≤0.05). The Connectivity Map identified seven candidate target drugs for the treatment of HCC, which were: Indolylheptylamine, mimosine, disopyramide, lidocaine, NU‑1025, bumetanide, and DQNLAOWBTJPFKL‑PKZXCIMASA‑N (all P≤0.05). Our findings indicated that LINC00668 may function as an oncogene and its overexpression indicates poor prognosis of HCC. FAM86C1, CTAG2 and SFN are of diagnostic significance, while FAM86C1, TDRD5, FTL and SFN are of prognostic significance for HCC.

Microenvironment-regulated lncRNA-HAL is able to promote stemness in breast cancer cells

Multicellular Tumor Spheroids culture (MCTS) is an in vitro model mimicking the characteristics of the tumor microenvironment, such as hypoxia and acidosis, resulting in the presence of both proliferating and quiescent cell populations. lncRNA's is a novel group of regulatory molecules that participates in the acquisition of tumorigenic phenotypes. In the present work we evaluated the oncogenic association of an uncharacterized lncRNA (lncRNA-HAL) in the tumorigenic phenotype induced by the MCTS microenvironment. We measured lncRNA-HAL expression level in MCF-7-MCTS populations and under different hypoxic conditions by RT-qPCR. Afterwards, we silenced lncRNA-HAL expression by shRNAs and evaluated its effect in MCF-7 transcriptome (by RNAseq) and validated the modified cellular processes by proliferation, migration, and stem cells assays. Finally, we analyzed which proteins interacts with lncRNA-HAL by ChIRP assay, to propose a possible molecular mechanism for this lncRNA. We found that lncRNA-HAL is overexpressed in the internal quiescent populations (p27 positive populations) of MCF-7-MCTS, mainly in the quiescent stem cell population, being hypoxia one of the microenvironmental cues responsible of its overexpression. Transcriptome analysis of lncRNA-HAL knockdown MCF7 cells revealed that lncRNA-HAL effect is associated with proliferation, migration and cell survival mechanisms; moreover, lncRNA-HAL silencing increased cell proliferation and impaired cancer stem cell proportion and function, resulting in decreased tumor grafting in vivo. In addition, we found that this lncRNA was overexpressed in triple-negative breast cancer patients. Analysis by ChIRP assay showed that this nuclear lncRNA binds to histones and hnRNPs suggesting a participation at the chromatin level and transcriptional regulation. The results obtained in the present work suggest that the function of lncRNA-HAL is associated with quiescent stem cell populations, which in turn is relevant due to its implications in cancer cell survival and resistance against treatment in vivo. Altogether, our data highlights a new lncRNA whose expression is regulated by the tumor microenvironment and associated to stemness in breast cancer.

Expression Pattern of Long Non-coding RNA Growth Arrest-specific 5 in the Remission Induction Therapy in Childhood Acute Lymphoblastic Leukemia

BACKGROUND

Long non-coding RNA growth arrest-specific 5 (GAS5) is deregulated in many cancers because of its role in cell growth arrest and apoptosis. Additionally, GAS5 interacts with glucocorticoid receptor, making it a potential pharmacotranscription marker of glucocorticoid (GC) therapy. In this study, we aimed at analysing GAS5 expression in the remission induction therapy phase of childhood acute lymphoblastic leukemia (ALL), in which GCs are mandatorily used, and to correlate it with therapy response.

METHODS

GAS5 expression was measured in peripheral blood mononuclear cells taken from 29 childhood ALL patients at diagnosis, on day 15 and day 33 of remission induction therapy using RT-qPCR methodology.

RESULTS

Our results have shown interindividual differences in GAS5 expression at all time points. For each ALL patient, GAS5 expression was higher on day 15 in comparison to its level at diagnosis (p<0.0005). On day 33, the level of GAS5 expression decreased in comparison with day 15 (p<0.0005), but it was still significantly higher than at diagnosis for the majority of patients (p=0.001). Patients whose number of blasts on day 8 was below 100 per μL of peripheral blood had a higher GAS5 expression at diagnosis (p=0.016), and lower ratio day 15/diagnosis (p=0.009).

CONCLUSIONS

Our results suggest that the expression level of GAS5 could be a potential marker of therapy response in remission induction therapy of childhood ALL.

Differential Plasma Expression Profiles of Long Non-Coding RNAs Reveal Potential Biomarkers for Systemic Lupus Erythematosus

Identify long non-coding RNAs (lncRNAs) that might serve as biomarkers for systemic lupus erythematosus (SLE) and explore the biological functions of the identified lncRNAs. In the screening phase, we examined the lncRNA expression profile of plasma samples from 24 patients with SLE and 12 healthy controls (HCs) using lncRNA microarray with pooled samples. The candidate lncRNAs were verified in individual samples by quantitative real-time (qRT)-PCR. In the independent validation stage, the identified lncRNAs were evaluated in 240 patients with SLE and 120 HCs. The identified lncRNAs were assessed further in an external validation stage including patients with rheumatoid arthritis (RA) and primary Sjögren’s syndrome (pSS). In addition, we constructed correlated expression networks including coding–non-coding co-expression and competing endogenous RNAs (ceRNAs). Plasma levels of linc0597, lnc0640, and lnc5150 were elevated in SLE patients compared with those of HCs, whereas levels of GAS5 and lnc7074 were decreased. Five lncRNAs were identified as potential SLE biomarkers with an area under the receiver operating characteristic curve (AUC) ranging from 0.604 to 0.833 in the independent validation phase. This panel of five lncRNAs had high diagnostic accuracy for SLE (AUC = 0.966) and distinguished SLE from RA and pSS (AUC = 0.683 and 0.910, respectively). Co-expression analysis showed that GAS5, lnc0640, and lnc5150 may participate in the SLE pathogenesis through the MAPK pathway. The ceRNA network indicated that GAS5, lnc0640, lnc3643, lnc6655, and lnc7074 bind competitively with microRNAs regulating the expression of target genes. Aberrant expression and related pathways suggest the important role of lncRNAs in SLE pathogenesis. In addition, the panel of five lncRNAs (GAS5, lnc7074, linc0597, lnc0640, and lnc5150) in plasma could be used as SLE biomarkers.

Role of long non-coding RNAs in lymphoma: A systematic review and clinical perspectives

Long non-coding RNAs (lncRNAs), are over 200 nucleotides in length, and they rarely act as templates for protein synthesis. Mounting studies have shown that lncRNAs play a crucial regulatory role in various processes that sustain life, such as epigenetic regulation, cell cycle control, splicing, and post-transcriptional regulation. LncRNAs were aberrantly expressed in most hematological malignancies including lymphoma, participating in tumor suppression or promoting oncogenesis and modulating key genes in different pathways. The specific expression patterns of lncRNAs in lymphoma make them good candidates to be used as diagnostic biomarkers or as therapeutic targets. LncRNAs can be targeted by multiple approaches including nucleic acid therapeutics, CRISPR/Cas genome editing techniques, small molecule inhibitors, and gene therapy. Efforts are made to develop therapeutic strategies aimed at targeting lncRNAs, but there are still some avenues to be covered before they can be applied to the clinical treatment of lymphoma.

The role of long non-coding RNA GAS5 in cancers

Long non-coding RNAs (lncRNAs) have shown potential as a biomarker in the diagnosis and prognosis in multiple cancers. LncRNAs are dysregulated in various cancers, playing either oncogenic or tumor suppressive roles. Emerging evidences have proved that the growth arrest-specific 5 (GAS5) lncRNA can function as a tumor suppressor in several cancers. LncRNA GAS5 is downregulated in many types of cancer, regulating cellular processes such as cell proliferation, apoptosis and invasion. The low level of GAS5 expression often elevates capacity of proliferation and predicts poorer prognosis in some cancers. This review aims to summarize the recent published literature on the biogenesis, regulation mechanism and function of GAS5 in different types of cancers and explore its potential for cancer diagnosis, prognosis and treatment.

Retracted: Knockdown of long noncoding RNA GAS5 attenuates H2 O2 -induced damage in retinal ganglion cells through upregulating miR-124: Potential role in traumatic brain injury

BACKGROUND

Optic nerve injury is one of the most common and serious complications in traumatic brain injury (TBI). Alleviating degree of optic nerve injury is important to cure of TBI. This study explored the role of long noncoding RNA (lncRNA) GAS5 in mice retinal ganglion cells (RGCs) suffered to H₂ O ₂ injury.

METHODS

Primary RGC (PRGCs) were treated with H₂ O ₂ to simulate an in vitro oxidation stress model. LncRNA GAS5 and miR-124 expressions were knocked down by cell transfection with short-hairpin RNA against GAS5 and miR-124 inhibitor, and the transfection efficiency was determined by qRT-PCR. Cell viability, apoptotic cell rate, and production of reactive oxygen species (ROS) was analyzed by CCK-8 assay, PI/FITC-Annexin V method, and DCFH-DA fluorometric assay. Cell apoptosis-associated proteins as well as activations of JAK/STAT3 signaling and JNK signaling were analyzed by Western blot.

RESULTS

H₂ O ₂ treatment-induced cell injury was inhibited by lncRNA GAS5 silence. Specifically, knockdown of GAS5 improved viability of primary PRGCs, inhibited apoptosis, decreased ROS expression, increased antiapoptosis proteins' expressions, and decreased proapoptosis proteins' expressions. It was also found that miR-124 inhibitor treatment impaired the cell protective effect of GAS5 silence, indicating low level of GAS5 protected PRGCs via upregulating miR-124. GAS5 silence might exert cytoprotection effect via activating JAK/STAT3 signaling pathway and inhibiting activation of JNK signaling pathway.

CONCLUSION

Knocking down lncRNA GAS5 alleviated H₂ O ₂ -induced injury in PRGCs via upregulation of miR-124, which might dependent on activation of JAK/STAT3 signaling pathway and inhibition of JNK signaling pathway.

Long non-coding RNA PSMB8-AS1 regulates influenza virus replication

Long non-coding RNAs (lncRNAs) are a new arm of gene regulatory mechanism as discovered by sequencing techniques and follow-up functional studies. There are only few studies on lncRNAs as related to gene expression regulation and anti-viral activity during influenza virus infection. We sought to identify and characterize lncRNAs involved in influenza virus replication. Using RNA sequencing analysis, we found that 1,912 lncRNAs were significantly changed in human lung epithelial A549 cells infected with influenza A/Puerto Rico/8/34. Gene ontology analysis on neighboring genes of these lncRNAs revealed that the genes involved in type I interferon signaling and cellular response were highly enriched. Seven selected up-regulated lncRNAs (AC015849.2, RP-1-7H24.1, PSMB8-AS1, CTD-2639E6.9, PSOR1C3, AC007283.5 and RP11-670E13.5) were verified by real-time PCR. These lncRNAs were also induced by other two influenza H1N1 virus strains (A/WSN/1933 and A/Oklahoma/3052/09) and interferon β1. Repression of PSMB8 antisense RNA 1 (PSMB8-AS1) using CRISPR interference reduced viral mRNA and protein levels as well as the release of progeny influenza virus particles. Our study suggests that lncRNA PSMB8-AS1 could be a new host factor target for developing antiviral therapy against influenza virus infection.

Long noncoding RNA GAS5 promotes apoptosis in primary nucleus pulposus cells derived from the human intervertebral disc via Bcl‑2 downregulation and caspase‑3 upregulation

Nucleus pulposus cell (NPC) apoptosis serves an important role in intervertebral disc degeneration (IDD); however, the roles of long noncoding RNAs (lncRNAs) in this process remain unknown. The present study aimed to determine the effects of the lncRNA growth arrest-specific transcript 5 (GAS5) on the apoptosis of primary human NPCs derived from the intervertebral disc, and to investigate the underlying mechanisms. TargetScan was used to predict the lncRNAs targeted by microRNA-155 (miR-155). Then, NPCs were subjected to lentivirus-mediated transduction of miR-155 or GAS5. A human lncRNA and mRNA array was used to screen differentially expressed lncRNAs following miR-155 overexpression. GAS5 and miR-155 expression levels were determined by reverse transcription-quantitative polymerase chain reaction. After GAS5 overexpression, apoptosis was assessed by flow cytometry via Annexin V/propidium iodide staining. Western blotting was employed to determine the expression of apoptosis-associated proteins, including caspase-3 and B cell lymphoma 2 (Bcl-2). TargetScan indicated GAS5 had one binding site for miR-155. Following exogenous transfection of miR-155 mimics, GAS5 expression levels in NPCs were significantly decreased (P<0.05). Interestingly, miR-155 overexpression in NPCs resulted in 721 differentially expressed lncRNAs compared with the negative control group (P<0.05), including 492 and 229 upregulated and downregulated lncRNAs respectively. In addition, 18 transcripts of GAS5 exhibited a downregulated expression profile. GAS5 overexpression in NPCs resulted in enhanced caspase-3 decreased Bcl-2 expression levels; the apoptosis of NPCs was significantly increased (P<0.05). The results of the present study revealed that overexpression of lncRNA GAS5 may promotes NPC apoptosis via Bcl-2 downregulation and caspase-3 upregulation, which may be associated with miR-155. The results of the present study suggest that lncRNA GAS5-silenced NPCs, or lentivirus-mediated lncRNA GAS5 knockdown may be precise and effective therapeutic strategies in the treatment of IDD.

Evidence for long noncoding RNA GAS5 up-regulationin patients with Klinefelter syndrome

Background

Klinefelter syndrome (KS) is characterized by the presence of at least one supernumerary X chromosome. KS typical symptoms include tall stature, gynecomastia, hypogonadism and azoospermia. KS patients show a higher risk of developing metabolic and cardiovascular diseases, inflammatory and autoimmune disorders, osteoporosis and cancer. Long non-coding RNA (lncRNA) growth arrest-specific 5 (GAS5) has been shown to be involved in several biologic processes, including inflammatory and autoimmune diseases, vascular endothelial cells apoptosis and atherosclerosis, as well as cellular growth and proliferation, cellular development and cell-to-cell signaling and interaction. The lncRNA GAS5 expression profile in KS patients has never been evaluated so far.

Methods

To accomplish this, GAS5 mRNA levels were evaluated by Next Generation Sequencing (NGS) technology and qRT-PCR assay in 10 patients with KS and 10 age-matched controls.

Results

NGS results showed a significantly lncRNAGAS5up-regulation by 5.171-fold in patients with KS. Theresults of qRT-PCR confirmed the NGS data.

Conclusions

These findings showed the occurrence of lncRNA GAS5 over-expression in KS patients. Whether this lncRNA is involved in the pathogenesis of inflammation and autoimmune diseases, atherogenesis or germ cell depletion in KS patients is not known. Further studies are needed.

Long non-coding RNA GAS5 promotes PC12 cells differentiation into Tuj1-positive neuron-like cells and induces cell cycle arrest

Growth arrest-specific 5 (GAS5) is an anti-oncogene that has been extensively studied in tumors. However, research on GAS5 in the context of nervous system disease is rare at present. This study aimed to investigate the role of the long non-coding RNA GAS5 in rat pheochromocytoma cells (PC12 cells). GAS5-overexpressing lentivirus was transfected into PC12 cells, and expression levels of GAS5 and C-myc were detected by real-time PCR. Ratios of cells in S phase were detected by 5-ethynyl-2′-deoxyuridine. Immunohistochemical staining was used to detect the immunoreactivity of neuron microtubule markers Tuj1, doublecortin, and microtubule-associated protein 2. Apoptosis was detected by flow cytometry, while expression of acetylcholine in cells was detected by western blot assay. We found that GAS5 can promote PC12 cells to differentiate into Tuj1-positive neuron-like cells with longer processes. In addition, cell proliferation and cell cycle were significantly suppressed by GAS5, whereas it had no effect on apoptosis of PC12 cells. Our results indicate that GAS5 could increase the expression of choline acetyltransferase and acetylcholine release. Thus, we speculate that GAS5 is beneficial to the recovery of neurons and the cholinergic nervous system.

The emerging role of lncRNAs in inflammatory bowel disease

Dysregulation of long noncoding RNA (lncRNA) expression is linked to the development of various diseases. Recently, an emerging body of evidence has indicated that lncRNAs play important roles in the pathogenesis of inflammatory bowel diseases (IBDs), including Crohn’s disease (CD) and ulcerative Colitis (UC). In IBD, lncRNAs have been shown to be involved in diverse processes, including the regulation of intestinal epithelial cell apoptosis, association with lipid metabolism, and cell–cell interactions, thereby enhancing inflammation and the functional regulation of regulatory T cells. In this review, we aim to summarize the current knowledge regarding the role of lncRNAs in IBD and highlight potential avenues for future investigation. We also collate potentially immune-relevant, IBD-associated lncRNAs identified through a built-by association analysis with respect to their neighboring protein-coding genes within IBD-susceptible loci. We further underscore their importance by highlighting their enrichment for various aspects of immune system regulation, including antigen processing/presentation, immune cell proliferation and differentiation, and chronic inflammatory responses. Finally, we summarize the potential of lncRNAs as diagnostic biomarkers in IBD.

Studying long noncoding RNAs (lncRNAs) may improve diagnosis and treatment of inflammatory bowel disease (IBD). These RNAs are found between genes in DNA regions previously thought to be “junk,” and have recently been shown to be important in development of various diseases. IBD, which includes both Crohn’s disease and ulcerative colitis, damages the digestive tract lining, causing pain and chronic diarrhea. A better understanding of IBD’s complex causes is needed to identify more effective treatments. Flemming Pociot at the Steno Diabetes Center in Gentofte, Denmark, and co-workers reviewed recent research linking lncRNAs and IBD. They discuss how lncRNAs’ roles in immunity and inflammation influence IBD development, describing how particular lncRNAs are related to IBD. Promising avenues for further research are highlighted, including the use of lncRNAs as biomarkers of IBD, which can be difficult to diagnose.

Loss of GAS5 tumour suppressor lncRNA: an independent molecular cancer biomarker for short-term relapse and progression in bladder cancer patients

Background

Bladder cancer (BlCa) heterogeneity and the lack of personalised prognosis lead to patients’ highly variable treatment outcomes. Here, we have analysed the utility of the GAS5 tumour-suppressor lncRNA in improving BlCa prognosis.

Methods

GAS5 was quantified in a screening cohort of 176 patients. Hedegaard et al. (2016) (n = 476) and TCGA provisional (n = 413) were used as validation cohorts. Survival analysis was performed using recurrence and progression for NMIBC, or death for MIBC. Internal validation was performed by bootstrap analysis, and decision curve analysis was used to evaluate the clinical benefit on disease prognosis.

Results

GAS5 levels were significantly downregulated in BlCa and associated with invasive high-grade tumours, and high EORTC-risk NMIBC patients. GAS5 loss was strongly and independently correlated with higher risk for NMIBC early relapse (HR = 2.680, p = 0.011) and progression (HR = 6.362, p = 0.035). Hedegaard et al. and TCGA validation cohorts’ analysis clearly confirmed the association of GAS5 loss with NMIBC worse prognosis. Finally, multivariate models incorporating GAS5 with disease established markers resulted in higher clinical benefit for NMIBC prognosis.

Conclusions

GAS5 loss is associated with adverse outcome of NMIBC and results in improved positive prediction of NMIBC patients at higher risk for short-term relapse and progression, supporting personalised prognosis and treatment decisions.

New advances of lncRNAs in liver fibrosis, with specific focus on lncRNA-miRNA interactions

Noncoding RNAs (ncRNAs) were initially thought to be transcriptional byproducts. However, recent advances of ncRNAs research have increased our understanding of the importance of ncRNA in gene regulation and disease pathogenesis. Consistent with these developments, liver fibrosis research is also experiencing rapid growth in the investigation of links between ncRNAs and the pathology of this disease. The initial focus was on studying the function and regulation mechanisms of microRNAs (miRNAs). However, recently, elucidation of the mechanisms of long noncoding RNAs (lncRNAs) and lncRNA-mediated liver fibrosis has just commenced. In this review, we emphasize on abnormal expression of lncRNAs in liver fibrosis. Furthermore, we also discuss that the interaction of lncRNAs with miRNAs is involved in the regulation of the expression of protein-coding genes in liver fibrosis. Recent advances in understanding dysregulated lncRNAs expression and the lncRNAs-miRNAs interaction in liver fibrosis will help for developing new therapeutic targets and biomarkers of liver fibrosis.

Regulation of hematopoiesis and immune responses by long non-coding RNAs

Since the first draft of the human genome sequence was released in 2001, unprecedentedly rapid progress has been made in whole genome-wide approaches by utilizing next-generation-sequencing technologies. The last decade alone has generated enormous data in the forms of exome sequencing, transcriptomes, transcription factor occupancy, genomic variation profiling and epigenetic modifications. One of the most striking realizations from sequencing studies has been the discovery and characterization of non-coding RNAs (ncRNAs). Although the extent to which ncRNAs are functional in vivo is still a controversial topic, there is at least a consensus that some ncRNAs are functional and that they play various roles in biology. Among the several kinds of ncRNAs, long ncRNAs (lncRNAs) in particular have received more attention because they have a larger potential to act as multifunctional regulators. Not surprisingly, researchers in the field of immunology have started to examine ncRNAs as new regulatory mechanisms. In this review, we will summarize some lncRNAs that have been reported to function in the immune system and then argue that there is still a long way to go before we can achieve a complete understanding of lncRNAs.

The long noncoding RNA GAS5 negatively regulates the adipogenic differentiation of MSCs by modulating the miR-18a/CTGF axis as a ceRNA

Mesenchymal stem cells (MSCs) are important pluripotent stem cells and a major source of adipocytes in the body. However, the mechanism of adipogenic differentiation has not yet been completely elucidated. In this study, the long noncoding RNA GAS5 was found to be negatively correlated with MSC adipogenic differentiation. GAS5 overexpression negatively regulated adipocyte formation, whereas GAS5 knockdown had the opposite effect. Further mechanistic analyses using luciferase reporter assays revealed that GAS5 regulates the adipogenic differentiation of MSCs by acting as competing endogenous RNA (ceRNA) to sponge miR-18a, which promotes adipogenic differentiation. Mutation of the binding sites for GAS5 in miR-18a abolished the effect of the interaction. The miR-18a mimic and inhibitor reversed the negative regulatory effect of GAS5 on MSCs adipogenic differentiation. In addition, GAS5 inhibited miR-18a, which downregulates connective tissue growth factor (CTGF) expression, to negatively regulate the adipogenic differentiation of MSCs. Taken together, the results show that GAS5 serves as a sponge for miR-18a, inhibiting its capability to suppress CTGF protein translation and ultimately decreasing the adipogenic differentiation of MSCs. GAS5 is an important molecule involved in the adipogenic differentiation of MSCs and may contribute to the functional regulation and clinical applications of MSCs.

The emerging co-regulatory role of long noncoding RNAs in epithelial-mesenchymal transition and the Warburg effect in aggressive tumors

Malignant tumor cells have several unique characteristics, and their ability to undergo epithelial-mesenchymal transition (EMT) is a molecular gateway to invasive behavior. Rapid proliferation and increased invasiveness during EMT enhance aberrant glucose metabolism in tumor cells. Meanwhile, aerobic glycolysis provides energy, biosynthesis precursors, and an appropriate microenvironment to facilitate EMT. Reciprocal crosstalk between the processes synergistically contributes to malignant cancer behaviors, but the regulatory mechanisms underlying this interaction remain unclear. Long non-coding RNAs (lncRNAs) are a recently recognized class of RNAs involved in multiple physiological and pathological tumor activities. Increasing evidence indicates that lncRNAs play overlapping roles in both EMT and cancer metabolism. In this review, we describe the lncRNAs reportedly involved in the two biological processes and explore the detailed mechanisms that could help elucidate this co-regulatory network and provide a theoretical basis for clinical management of EMT-related malignant phenotypes.

Down-regulation of lncRNA, GAS5 decreases chemotherapeutic effect of dendrosomal curcumin (DNC) in breast cancer cells

BACKGROUND

Despite positive results obtained from anticancer activities of curcumin, there are some obstacles that limit its use as an anticancer agent.

HYPOTHESIS/PURPOSE

Different methods such as employing the dendrosomal curcumin (DNC) were examined to overcome such problems. There is increasing evidence representing long non-coding RNAs play important roles in biological processes. In this study, we focused on the roles of GAS5 in the anti-cancer effects of DNC on breast cancer.

METHODS

We used several methods including MTT assay, apoptosis assay, cell cycle analysis, transwell migration assay and RT-PCR.

RESULTS

We observed a significant increase in the expression of Tusc7, and GAS5 genes with DNC treatment of MCF7, MDA-MB231, and SKBR3 cells. Also, the combination of GAS5 down-regulation and DNC treatment showed lower percentages of apoptotic cells and a higher level of penetration through the membrane compared with DNC treatment alone. Furthermore, DNC induced a significant increase in the number of cells in sub G1/G1 phase and a decrease in the G2/M phase of the cell cycle. But, after GAS5 down-regulation alone opposite results was observed compared to DNC.

CONCLUSION

We observed that GAS5 down-regulation can suppress many aspects of DNC anti-cancer effects in breast cancer cells, it seems that co-treatment with DNC and GAS5 over-expression may provide a clinically useful tool for drug-resistance breast cancer cells.

Comprehensive analysis of lncRNAs microarray profile and mRNA-lncRNA co-expression in oncogenic HPV-positive cervical cancer cell lines

Long non-coding RNAs are emerging to be novel regulators in gene expression. In current study, lncRNAs microarray and lncRNA-mRNA co-expression analysis were performed to explore the alternation and function of lncRNAs in cervical cancer cells. We identified that 4750 lncRNAs (15.52%) were differentially expressed in SiHa (HPV-16 positive) (2127 up-regulated and 2623 down-regulated) compared with C-33A (HPV negative), while 5026 lncRNAs (16.43%) were differentially expressed in HeLa (HPV-18 positive) (2218 up-regulated and 2808 down-regulated) respectively. There were 5008 mRNAs differentially expressed in SiHa and 4993 in HeLa, which were all cataloged by GO terms and KEGG pathway. With the help of mRNA-lncRNA co-expression network, we found that ENST00000503812 was significantly negative correlated with RAD51B and IL-28A expression in SiHa, while ENST00000420168, ENST00000564977 and TCONS_00010232 had significant correlation with FOXQ1 and CASP3 expression in HeLa. Up-regulation of ENST00000503812 may inhibit RAD51B and IL-28A expression and result in deficiency of DNA repair pathway and immune responses in HPV-16 positive cervical cancer cell. Up-regulation of ENST00000420168, ENST00000564977 and down-regulation of TCONS_00010232 might stimulate FOXQ1 expression and suppress CASP3 expression in HPV-18 positive cervical cancer cell, which lead to HPV-induced proliferation and deficiency in apoptosis. These results indicate that changes of lncRNAs and related mRNAs might impact on several cellular pathways and involve in HPV-induced proliferation, which enriches our understanding of lncRNAs and coding transcripts anticipated in HPV oncogenesis of cervical cancer.

Differentially expressed host long intergenic noncoding RNA and mRNA in HIV-1 and HIV-2 infection

Non-coding RNAs and mRNAs have been implicated in replication, pathogenesis and host response in HIV infection. However, the impact of long intergenic non-coding RNAs (lincRNAs) on HIV-1 and HIV-2 infection is not known. In this study, we have analyzed expression profiles of lincRNAs and mRNAs in monocyte derived macrophages (MDMs) infected with HIV-1/HIV-2 using microarrays. Our study identified many differentially expressed lincRNAs and mRNAs in MDMs infected with HIV-1/HIV-2 compared to uninfected MDMs. Genes involved in glutathione metabolism and lysine degradation were differentially regulated only in HIV-1 infected MDMs. In HIV-2 infected MDMs, CUL 2, SFRS9, and RBBP4 genes were differentially expressed. Furthermore, we found that plasma levels of lincRNA: chr2: 165509129-165519404 and lincRNA: chr12: 57761837-57762303 were better indicators of HIV-1 infection while lincRNA: chr10:128586385-128592960, XLOC_001148 and lincRNA: chr5:87580664-87583451, were better indicators of HIV-2 infection. In summary, our study has demonstrated that there is substantial alteration in lincRNA and mRNA expression in response to HIV-1/HIV-2 infection. These differentially expressed lincRNAs and mRNAs could serve as prognostic and diagnostic biomarkers of HIV infection and help in the identification of new targets for therapy.

Critical effects of long non-coding RNA on fibrosis diseases

The expression or dysfunction of long non-coding RNAs (lncRNAs) is closely related to various hereditary diseases, autoimmune diseases, metabolic diseases and tumors. LncRNAs were also recently recognized as functional regulators of fibrosis, which is a secondary process in many of these diseases and a primary pathology in fibrosis diseases. We review the latest findings on lncRNAs in fibrosis diseases of the liver, myocardium, kidney, lung and peritoneum. We also discuss the potential of disease-related lncRNAs as therapeutic targets for the clinical treatment of human fibrosis diseases.

Identification and characterization of conserved lncRNAs in human and rat brain

BACKGROUND

Long noncoding RNAs (lncRNAs) are involved in diverse biological processes and play an essential role in various human diseases. The number of lncRNAs identified has increased rapidly in recent years owing to RNA sequencing (RNA-Seq) technology. However, presently, most lncRNAs are not well characterized, and their regulatory mechanisms remain elusive. Many lncRNAs show poor evolutionary conservation. Thus, the lncRNAs that are conserved across species can provide insight into their critical functional roles.

RESULTS

Here, we performed an orthologous analysis of lncRNAs in human and rat brain tissues. Over two billion RNA-Seq reads generated from 80 human and 66 rat brain tissue samples were analyzed. Our analysis revealed a total of 351 conserved human lncRNAs corresponding to 646 rat lncRNAs. Among these human lncRNAs, 140 were newly identified by our study, and 246 were present in known lncRNA databases; however, the majority of the lncRNAs that have been identified are not yet functionally annotated. We constructed co-expression networks based on the expression profiles of conserved human lncRNAs and protein-coding genes, and produced 79 co-expression modules. Gene ontology (GO) analysis of the co-expression modules suggested that the conserved lncRNAs were involved in various functions such as brain development (P-value = 1.12E-2), nervous system development (P-value = 1.26E-3), and cerebral cortex development (P-value = 1.31E-2). We further predicted the interactions between lncRNAs and protein-coding genes to better understand the regulatory mechanisms of lncRNAs. Moreover, we investigated the expression patterns of the conserved lncRNAs at different time points during rat brain growth. We found that the expression levels of three out of four such lncRNA genes continuously increased from week 2 to week 104, which is consistent with our functional annotation.

CONCLUSION

Our orthologous analysis of lncRNAs in human and rat brain tissues revealed a set of conserved lncRNAs. Further expression analysis provided the functional annotation of these lncRNAs in humans and rats. Our results offer new targets for developing better experimental designs to investigate regulatory molecular mechanisms of lncRNAs and the roles lncRNAs play in brain development. Additionally, our method could be generalized to study and characterize lncRNAs conserved in other species and tissue types.

Long Non-Coding RNAs: Emerging and Versatile Regulators in Host-Virus Interactions

Long non-coding RNAs (lncRNAs) are a class of non-protein-coding RNA molecules, which are involved in various biological processes, including chromatin modification, cell differentiation, pre-mRNA transcription and splicing, protein translation, etc. During the last decade, increasing evidence has suggested the involvement of lncRNAs in both immune and antiviral responses as positive or negative regulators. The immunity-associated lncRNAs modulate diverse and multilayered immune checkpoints, including activation or repression of innate immune signaling components, such as interleukin (IL)-8, IL-10, retinoic acid inducible gene I, toll-like receptors 1, 3, and 8, and interferon (IFN) regulatory factor 7, transcriptional regulation of various IFN-stimulated genes, and initiation of the cell apoptosis pathways. Additionally, some virus-encoded lncRNAs facilitate viral replication through individually or synergistically inhibiting the host antiviral responses or regulating multiple steps of the virus life cycle. Moreover, some viruses are reported to hijack host-encoded lncRNAs to establish persistent infections. Based on these amazing discoveries, lncRNAs are an emerging hotspot in host–virus interactions. In this review, we summarized the current findings of the host- or virus-encoded lncRNAs and the underlying mechanisms, discussed their impacts on immune responses and viral replication, and highlighted their critical roles in host–virus interactions.

Arsenic exposure during embryonic development alters the expression of the long noncoding RNA growth arrest specific-5 (Gas5) in a sex-dependent manner

Our previous studies suggest that prenatal arsenic exposure (50ppb) modifies epigenetic control of the programming of the glucocorticoid receptor (GR) signaling system in the developing mouse brain. These deficits may lead to long-lasting consequences, including deficits in learning and memory, increased depressive-like behaviors, and an altered set-point of GR feedback throughout life. To understand the arsenic-induced changes within the GR system, we assessed the impact of in utero arsenic exposure on the levels of the GR and growth arrest-specific-5 (Gas5), a noncoding RNA, across a key gestational period for GR programming (gestational days, GD 14-18) in mice. Gas5 contains a glucocorticoid response element (GRE)-like sequence that binds the GR, thereby decreasing GR-GRE-dependent gene transcription and potentially altering GR programming. Prenatal arsenic exposure resulted in sex-dependent and age-dependent shifts in the levels of GR and Gas5 expression in fetal telencephalon. Nuclear GR levels were reduced in males, but unchanged in females, at all gestational time points tested. Total cellular Gas5 levels were lower in arsenic-exposed males with no changes seen in arsenic-exposed females at GD16 and 18. An increase in total cellular Gas-5 along with increased nuclear levels in GD14 arsenic-exposed females, suggests a differential regulation of cellular compartmentalization of Gas5. RIP assays revealed reduced Gas5 associated with the GR on GD14 in the nuclear fraction prepared from arsenic-exposed males and females. This decrease in levels of GR-Gas5 binding continued only in the females at GD18. Thus, nuclear GR signaling potential is decreased in prenatal arsenic-exposed males, while it is increased or maintained at levels approaching normal in prenatal arsenic-exposed females. These findings suggest that females, but not males, exposed to arsenic are able to regulate the levels of nuclear free GR by altering Gas5 levels, thereby keeping GR nuclear signaling closer to control (unexposed) levels.

Dysregulated long noncoding RNAs (lncRNAs) in hepatocellular carcinoma: implications for tumorigenesis, disease progression, and liver cancer stem cells

Hepatocellular carcinoma (HCC) is one of the most common malignant tumours with a poor prognosis worldwide. While early stage tumours can be treated with curative approaches such as liver transplantation or surgical resection, these are only suitable for a minority of patients. Those with advanced stage disease are only suitable for supportive approaches and most are resistant to the conventional chemotherapy or radiotherapy. Liver cancer stem cells (LCSCs) are a small subset of cancer cells with unlimited differentiation ability and tumour forming potential. In order to develop novel therapeutic approaches for HCC, we need to understand how the cancer develops and why treatment resistance occurs. Using high-throughput sequencing techniques, a large number of dysregulated long noncoding RNAs (lncRNAs) have been identified, and some of which are closely linked to key aspects of liver cancer pathology, progression, outcomes and for the maintenance of cancer stem cell-like properties. In addition, some lncRNAs are potential biomarkers for HCC diagnosis and may serve as the therapeutic targets. This review summarizes data recently reported lncRNAs that might be critical for the maintenance of the biological properties of LCSCs.

Emerging roles for long noncoding RNAs in B-cell development and malignancy

Long noncoding (lnc)RNAs have emerged as essential mediators of cellular biology, differentiation and malignant transformation. LncRNAs have a broad range of possible functions at the transcriptional, posttranscriptional and protein level and their aberrant expression significantly contributes to the hallmarks of cancer cell biology. In addition, their high tissue- and cell-type specificity makes lncRNAs especially interesting as biomarkers, prognostic factors or specific therapeutic targets. Here, we review current knowledge on lncRNA expression changes during normal B-cell development, indicating essential functions in the differentiation process. In addition we address lncRNA deregulation in B-cell malignancies, the putative prognostic value of this as well as the molecular functions of multiple deregulated lncRNAs. Altogether, the discussed work indicates major roles for lncRNAs in normal and malignant B cells affecting oncogenic pathways as well as the response to common therapeutics.

Differential Expression Profile of lncRNAs from Primary Human Hepatocytes Following DEET and Fipronil Exposure

While the synthesis and use of new chemical compounds is at an all-time high, the study of their potential impact on human health is quickly falling behind, and new methods are needed to assess their impact. We chose to examine the effects of two common environmental chemicals, the insect repellent N,N-diethyl-m-toluamide (DEET) and the insecticide fluocyanobenpyrazole (fipronil), on transcript levels of long non-protein coding RNAs (lncRNAs) in primary human hepatocytes using a global RNA-Seq approach. While lncRNAs are believed to play a critical role in numerous important biological processes, many still remain uncharacterized, and their functions and modes of action remain largely unclear, especially in relation to environmental chemicals. RNA-Seq showed that 100 µM DEET significantly increased transcript levels for 2 lncRNAs and lowered transcript levels for 18 lncRNAs, while fipronil at 10 µM increased transcript levels for 76 lncRNAs and decreased levels for 193 lncRNAs. A mixture of 100 µM DEET and 10 µM fipronil increased transcript levels for 75 lncRNAs and lowered transcript levels for 258 lncRNAs. This indicates a more-than-additive effect on lncRNA transcript expression when the two chemicals were presented in combination versus each chemical alone. Differentially expressed lncRNA genes were mapped to chromosomes, analyzed by proximity to neighboring protein-coding genes, and functionally characterized via gene ontology and molecular mapping algorithms. While further testing is required to assess the organismal impact of changes in transcript levels, this initial analysis links several of the dysregulated lncRNAs to processes and pathways critical to proper cellular function, such as the innate and adaptive immune response and the p53 signaling pathway.

Long non-coding RNA growth arrest specific transcript 5 acts as a tumour suppressor in colorectal cancer by inhibiting interleukin-10 and vascular endothelial growth factor expression

Long non-coding RNAs (lncRNAs) are highly involved in diverse biological processes of human malignancies. The expression profile and underlying mechanism of lncRNA growth arrest specific transcript 5 (GAS5) in colorectal cancer (CRC) is poorly understood. In this study, we found that GAS5 was commonly downregulated in CRC tissues, serum of CRC patients and CRC cell lines. Knockdown of GAS5 promoted CRC cell proliferation and colony formation, whereas overexpression of GAS5 produced the opposite result. We further demonstrated that knockdown of GAS5 increased the expression and secretion of interleukin-10 (IL-10) and vascular endothelial growth factor (VEGF-A) via NF-κB and Erk1/2 pathways. Neutralization of IL-10 and VEGF-A reduced tumour proliferation caused by GAS5 knockdown. Moreover, GAS5 expression showed a statistically significant correlation with the mRNA levels of IL-10 and VEGF-A in CRC tissues. We further illustrated that GAS5 was markedly downregulated and negatively correlated with the cytokine expression in a mouse model of colitis-associated cancer (CAC). These results delineate a novel mechanism of lncRNA GAS5 in suppressing colorectal carcinogenesis. The cytokines IL-10 and VEGF-A inhibited by GAS5 may provide targets for lncRNA-based therapies for CRC.

Retroviral insertional mutagenesis implicates E3 ubiquitin ligase RNF168 in the control of cell proliferation and survival

The E3 ubiquitin ligase RNF168 is a ring finger protein that has previously been identified to play an important regulatory role in the repair of double-strand DNA breaks.  In the present study, an unbiased forward genetics functional screen in mouse granulocyte/ macrophage progenitor cell line FDCP1 has identified E3 ubiquitin ligase RNF168 as a key regulator of cell survival and proliferation. Our data indicate that RNF168 is an important component of the mechanisms controlling cell fate, not only in human and mouse haematopoietic growth factor-dependent cells, but also in the human breast epithelial cell line MCF-7. These observations therefore suggest that RNF168 provides a connection to key pathways controlling cell fate, potentially through interaction with PML nuclear bodies and/or epigenetic control of gene expression. Our study is the first to demonstrate a critical role for RNF168 in the in the mechanisms regulating cell proliferation and survival, in addition to its well-established role in DNA repair.

LncRNA GAS5 inhibits microglial M2 polarization and exacerbates demyelination

The regulation of inflammation is pivotal for preventing the development or reoccurrence of multiple sclerosis (MS). A biased ratio of high‐M1 versus low‐M2 polarized microglia is a major pathological feature of MS. Here, using microarray screening, we identify the long noncoding RNA (lncRNA) GAS5 as an epigenetic regulator of microglial polarization. Gain‐ and loss‐of‐function studies reveal that GAS5 suppresses microglial M2 polarization. Interference with GAS5 in transplanted microglia attenuates the progression of experimental autoimmune encephalomyelitis (EAE) and promotes remyelination in a lysolecithin‐induced demyelination model. In agreement, higher levels of GAS5 are found in amoeboid‐shaped microglia in MS patients. Further, functional studies demonstrate that GAS5 suppresses transcription of TRF4, a key factor controlling M2 macrophage polarization, by recruiting the polycomb repressive complex 2 (PRC2), thereby inhibiting M2 polarization. Thus, GAS5 may be a promising target for the treatment of demyelinating diseases.

lncRNA LINC00152 knockdown had effects to suppress biological activity of lung cancer via EGFR/PI3K/AKT pathway

Accumulating evidence demonstrates that lncRNAs play important roles in regulating gene expression and are involved in various pathological processes. In our present study, we firstly evaluated lncRNA LINC00152 and EGFR expressions by ISH or IHC methods, and analyzed the correlation between LINC00152 and EGFR with RT-PCR. lncRNA LINC00152 of NSCLC tissues were significantly up-regulation compared with adjacent normal tissues and positively correlated with EGPR. The further cell experiments demonstrated that Linc00152 knockdown had effects of suppression cell proliferation, invasion and migration abilities and improving cell apoptosis and G1 phase rates in both A549 and H1299 cell lines. In the mechanism study, the results were shown that EGFR, PI3K, AKT, Fibronectin and Vimentin proteins expressions were significantly reduced and P21 protein expression was significantly increased in Linc00152 knockdown groups. Our results suggested lncRNA LINC00152 knock-down had anti-tumor effects via EGFR/PI3K/AKT pathway.

Systematic review and meta-analysis of the utility of long non-coding RNA GAS5 as a diagnostic and prognostic cancer biomarker

The growth arrest-specific 5 transcript (GAS5) is a long non-coding RNA (lncRNA) involved in the control of cell cycle progression and apoptosis in a wide variety of cells. To determine the clinical value of GAS5 expression in cancer patients, we performed a systematic review and meta-analysis exploring its association with the diagnosis, prognosis, and clinicopathological characteristics of cancer. Ten articles on prognosis, 15 on clinicopathology, and 5 on diagnosis were analyzed. Overall results showed that decreased GAS5 expression associated with unfavorable overall survival (OS) (HR = 2.50, 95%CI: 1.85–3.38, P < 0.001) and disease-free survival (DFS) (HR = 2.24, 95%CI: 1.58–3.18, P < 0.001) in several tumor types. Down-regulation of GAS5 correlated with poor recurrence-free survival (RFS) in hepatocellular carcinoma (HR = 2.40, 95%CI: 1.27–4.54, P = 0.007), and was associated with lymph node metastasis (OR = 1.92, 95% CI: 1.44–2.57, P < 0.001), distant metastasis (OR = 2.7, 95% CI: 1.05–6.97, P = 0.040), poor clinical stage (OR = 0.26, 95% CI: 0.18–0.38, P < 0.001), larger tumor size (OR = 3.21, 95% CI: 2.08–4.95, P < 0.001), and poor tumor differentiation (OR = 1.98, 95% CI: 1.40–2.80, P < 0.001). Pooled results of diagnostic data analysis showed that GAS5 exhibited a sensitivity of 0.76 and specificity of 0.64 for cancer diagnosis, and an area under the curve of 0.76 (95% CI: 0.72–0.80) indicated moderate diagnostic accuracy. This meta-analysis suggests GAS5 lncRNA may be a useful diagnostic and prognostic cancer biomarker, and may be especially useful for identifying patients prone to developing lymph node or distant metastasis.

C/D-box snoRNAs form methylating and non-methylating ribonucleoprotein complexes: Old dogs show new tricks

C/D box snoRNAs (SNORDs) are an abundantly expressed class of short, non-coding RNAs that have been long known to perform 2'-O-methylation of rRNAs. However, approximately half of human SNORDs have no predictable rRNA targets, and numerous SNORDs have been associated with diseases that show no defects in rRNAs, among them Prader-Willi syndrome, Duplication 15q syndrome and cancer. This apparent discrepancy has been addressed by recent studies showing that SNORDs can act to regulate pre-mRNA alternative splicing, mRNA abundance, activate enzymes, and be processed into shorter ncRNAs resembling miRNAs and piRNAs. Furthermore, recent biochemical studies have shown that a given SNORD can form both methylating and non-methylating ribonucleoprotein complexes, providing an indication of the likely physical basis for such diverse new functions. Thus, SNORDs are more structurally and functionally diverse than previously thought, and their role in gene expression is under-appreciated. The action of SNORDs in non-methylating complexes can be substituted with oligonucleotides, allowing devising therapies for diseases like Prader-Willi syndrome.

LncRNA GAS5 Inhibits Cellular Proliferation by Targeting P27Kip1

Recent studies have demonstrated that long noncoding RNAs (lncRNA) have important roles in cancer biology, and that the downregulation of lncRNA growth arrest-specific transcript 5 (GAS5) has been reported in a variety of human cancers. However, its role in prostate cancer is largely unknown. This study aims to investigate the biological role and underlying mechanism of GAS5 on proliferation in prostate cancer. The results demonstrate that GAS5 expression is significantly decreased in prostate cancer cells compared with prostate epithelial cells. Ectopic expression of GAS5 inhibited cell proliferation and induced a cell-cycle arrest in G₀-G₁ phase, whereas GAS5 knockdown promoted the G₁-S phase transition. Subsequent analysis demonstrated that P27^Kip1, a known regulator of cell cycle, was positively regulated by GAS5 and upregulation of GAS5 increased its promoter activity. E2F1, an important transcription factor, was shown to bind directly to and activate the P27^Kip1 promoter. In addition, GAS5 interacted with E2F1 and enhanced the binding of E2F1 to the P27^Kip1 promoter. Collectively, these findings determine that GAS5 functions as a tumor suppressor in prostate cancer development and progression via targeting P27^Kip1Implications: This study reveals a molecular pathway involving lncRNA GAS5/E2F1/P27^Kip1 which regulates cell proliferation and could be a potential therapeutic target in prostate cancer. Mol Cancer Res; 15(7); 789-99. ©2017 AACR.

Long non-coding RNA GAS5 inhibits cell proliferation, induces G0/G1 arrest and apoptosis, and functions as a prognostic marker in colorectal cancer

Colorectal cancer (CRC) is the third most common cancer worldwide and its treatment remains a challenge. Effective control of cell survival and proliferation is critical in the prevention of oncogenesis and successful treatment of cancer. Long non-coding RNAs (lncRNAs) have emerged as primary regulators of carcinogenesis. Growth arrest specific 5 (GAS5), a lncRNA, is known to be aberrantly expressed in several types of cancer, however, the role of GAS5 in CRC remains unclear. In the present study, GAS5 mRNA expression was measured in CRC and adjacent normal mucosa tissue samples from 53 patients using reverse transcription-quantitative polymerase chain reaction analysis, in addition to seven CRC cell lines. GAS5 mRNA expression was observed to be markedly downregulated in human CRC tissues and cell lines. Decreased GAS5 expression was associated with an increase in tumor diameter [odds ratio (OR), 0.176 (95% CI, 0.053-0.586); P=0.003] and later tumor-node-metastasis stage [OR, 0.261 (95% CI, 0.083-0.819); P=0.019]. Patients with decreased GAS5 expression exhibited decreased overall survival rates compared with patients with increased GAS5 expression (P=0.015). The Cox proportional hazards model demonstrated that downregulated GAS5 expression was an independent prognostic factor for CRC (hazard ratio, 0.236; 95% confidence interval, 0.067-0.827; P=0.024). Functional assays demonstrated that overexpression of GAS5 inhibited cell proliferation and survival, and induced G0/G1 cell cycle arrest and apoptosis; however, knockdown of GAS5 expression enhanced cell proliferation, and reduced G0/G1 arrest and apoptosis. In conclusion, the results of the present study suggest that GAS5 is essential in the control of apoptosis and cell growth in CRC. Therefore, GAS5 may represent a novel prognostic and diagnostic marker of CRC, in addition to being a potential therapeutic target.