Increased level of H19 long noncoding RNA promotes invasion, angiogenesis, and stemness of glioblastoma cells

KHDRBS3 facilitates self-renewal and temozolomide resistance of glioblastoma cell lines

Glioblastoma is a deadly tumor which possesses glioblastoma stem cell populations involved in temozolomide (TMZ) resistance. To gain insight into the mechanisms of self-renewing and therapy-resistant cancer stem cells, subcellular proteomics was utilized to identify proteins whose expression is enriched in U251-derived glioblastoma stem-like cells. The KH RNA Binding Domain Containing, Signal Transduction Associated 3, KHDRBS3, was successfully identified as a gene up-regulated in the cancer stem cell population compared with its differentiated derivatives. Depletion of KHDRBS3 by RNA silencing led to a decrease in cell proliferation, neurosphere formation, migration, and expression of genes involved in glioblastoma stemness. Importantly, TMZ sensitivity can be induced by the gene knockdown. Collectively, our results highlight KHDRBS3 as a novel factor associated with self-renewal of glioblastoma stem-like cells and TMZ resistance. As a consequence, targeting KHDRBS3 may help eradicate glioblastoma stem-like cells.

Glioblastoma stem cell long non-coding RNAs: therapeutic perspectives and opportunities

Glioblastoma poses a formidable challenge among primary brain tumors: its tumorigenic stem cells, capable of self-renewal, proliferation, and differentiation, contribute substantially to tumor initiation and therapy resistance. These glioblastoma stem cells (GSCs), resembling conventional stem and progenitor cells, adopt pathways critical for tissue development and repair, promoting uninterrupted tumor expansion. Long non-coding RNAs (lncRNAs), a substantial component of the human transcriptome, have garnered considerable interest for their pivotal roles in normal physiological processes and cancer pathogenesis. They display cell- or tissue-specific expression patterns, and extensive investigations have highlighted their impact on regulating GSC properties and cellular differentiation, thus offering promising avenues for therapeutic interventions. Consequently, lncRNAs, with their ability to exert regulatory control over tumor initiation and progression, have emerged as promising targets for innovative glioblastoma therapies. This review explores notable examples of GSC-associated lncRNAs and elucidates their functional roles in driving glioblastoma progression. Additionally, we delved deeper into utilizing a 3D in vitro model for investigating GSC biology and elucidated four primary methodologies for targeting lncRNAs as potential therapeutics in managing glioblastoma.

Long noncoding RNA H19: functions and mechanisms in regulating programmed cell death in cancer

Long noncoding RNAs (lncRNAs) are a group of noncoding RNAs with transcript lengths of >200 nucleotides. Mounting evidence suggests that lncRNAs are closely associated with tumorigenesis. LncRNA H19 (H19) was the first lncRNA to function as an oncogene in many malignant tumors. Apart from the established role of H19 in promoting cell growth, proliferation, invasion, migration, epithelial-mesenchymal transition (EMT), and metastasis, it has been recently discovered that H19 also inhibits programmed cell death (PCD) of cancer cells. In this review, we summarize the mechanisms by which H19 regulates PCD in cancer cells through various signaling pathways, molecular mechanisms, and epigenetic modifications. H19 regulates PCD through the Wnt/β-catenin pathway and the PI3K-Akt-mTOR pathway. It also acts as a competitive endogenous RNA (ceRNA) in PCD regulation. The interaction between H19 and RNA-binding proteins (RBP) regulates apoptosis in cancer. Moreover, epigenetic modifications, including DNA and RNA methylation and histone modifications, are also involved in H19-associated PCD regulation. In conclusion, we summarize the role of H19 signaling via PCD in cancer chemoresistance, highlighting the promising research significance of H19 as a therapeutic target. We hope that our study will contribute to a broader understanding of H19 in cancer development and treatment.

Identification of glioblastoma stem cell-associated lncRNAs using single-cell RNA sequencing datasets

Glioblastoma multiforme (GBM) is an aggressive, heterogeneous brain tumor in which glioblastoma stem cells (GSCs) are known culprits of therapy resistance. Long non-coding RNAs (lncRNAs) have been shown to play a critical role in both cancer and normal biology. A few studies have suggested that aberrant expression of lncRNAs is associated with GSCs. However, a comprehensive single-cell analysis of the GSC-associated lncRNA transcriptome has not been carried out. Here, we analyzed recently published single-cell RNA sequencing datasets of adult GBM tumors, GBM organoids, GSC-enriched GBM tumors, and developing human brain samples to identify lncRNAs highly expressed in GSCs. We further revealed that the GSC-specific lncRNAs GIHCG and LINC01563 promote proliferation, migration, and stemness in the GSC population. Together, this study identified a panel of uncharacterized GSC-enriched lncRNAs and set the stage for future in-depth studies to examine their role in GBM pathology and their potential as biomarkers and/or therapeutic targets in GBM.

H19 recruited m6A reader YTHDF1 to promote SCARB1 translation and facilitate angiogenesis in gastric cancer

BACKGROUND

Angiogenesis is described as a complex process in which new microvessels sprout from endothelial cells of existing vasculature. This study aimed to determine whether long non-coding RNA (lncRNA) H19 induced the angiogenesis of gastric cancer (GC) and its possible mechanism.

METHODS

Gene expression level was determined by quantitative real-time polymerase chain reaction and western blotting. Cell counting kit-8, transwell, 5-Ethynyl-2'-deoxyuridine (EdU), colony formation assay, and human umbilical vein endothelial cells (HUVECs) angiogenesis assay as well as Matrigel plug assay were conducted to study the proliferation, migration, and angiogenesis of GC in vitro and in vivo. The binding protein of H19 was found by RNA pull-down and RNA Immunoprecipitation (RIP). High-throughput sequencing was performed and next Gene Ontology (GO) as well as Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis was conducted to analyze the genes that are under H19 regulation. Methylated RIP (me-RIP) assay was used to investigate the sites and abundance among target mRNA. The transcription factor acted as upstream of H19 was determined through chromatin immunoprecipitation (ChIP) and luciferase assay.

RESULTS

In this study, we found that hypoxia-induced factor (HIF-1α) could bind to the promoter region of H19, leading to H19 overexpression. High expression of H19 was correlated with angiogenesis in GC, and H19 knocking down could inhibit cell proliferation, migration and angiogenesis. Mechanistically, the oncogenic role of H19 was achieved by binding with the N6-methyladenosine (m6A) reader YTH domain-containing family protein 1 (YTHDF1), which could recognize the m6A site on the 3'-untransated regions (3'-UTR) of scavenger receptor class B member 1 (SCARB1) mRNA, resulting in over-translation of SCARB1 and thus promoting the proliferation, migration, and angiogenesis of GC cells.

CONCLUSION

HIF-1α induced overexpression of H19 via binding with the promoter of H19, and H19 promoted GC cells proliferation, migration and angiogenesis through YTHDF1/SCARB1, which might be a beneficial target for antiangiogenic therapy for GC.

Identification of glioblastoma stem cell-associated lncRNAs using single-cell RNA-sequencing datasets

Glioblastoma multiforme (GBM) is an aggressive, heterogeneous grade IV brain tumor. Glioblastoma stem cells (GSCs) initiate the tumor and are known culprits of therapy resistance. Mounting evidence has demonstrated a regulatory role of long non-coding RNAs (lncRNAs) in various biological processes, including pluripotency, differentiation, and tumorigenesis. A few studies have suggested that aberrant expression of lncRNAs is associated with GSCs. However, a comprehensive single-cell analysis of the GSC-associated lncRNA transcriptome has not been carried out. Here, we analyzed recently published single-cell RNA-sequencing datasets of adult human GBM tumors, GBM organoids, GSC-enriched GBM tumors, and developing human brains to identify lncRNAs highly expressed in GBM. To categorize GSC populations in the GBM tumors, we used the GSC marker genes SOX2, PROM1, FUT4, and L1CAM. We found three major GSC population clusters: radial glia, oligodendrocyte progenitor cells, and neurons. We found 10â€"100 lncRNAs significantly enriched in different GSC populations. We also validated the level of expression and localization of several GSC-enriched lncRNAs using qRT-PCR, single-molecule RNA FISH, and sub-cellular fractionation. We found that the radial glia GSC-enriched lncRNA PANTR1 is highly expressed in GSC lines and is localized to both the cytoplasmic and nuclear fractions. In contrast, the neuronal GSC-enriched lncRNAs LINC01563 and MALAT1 are highly enriched in the nuclear fraction of GSCs. Together, this study identified a panel of uncharacterized GSC-specific lncRNAs. These findings set the stage for future in-depth studies to examine their role in GBM pathology and their potential as biomarkers and/or therapeutic targets in GBM.

Non-coding RNAs and glioma: Focus on cancer stem cells

Glioblastoma and gliomas can have a wide range of histopathologic subtypes. These heterogeneous histologic phenotypes originate from tumor cells with the distinct functions of tumorigenesis and self-renewal, called glioma stem cells (GSCs). GSCs are characterized based on multi-layered epigenetic mechanisms, which control the expression of many genes. This epigenetic regulatory mechanism is often based on functional non-coding RNAs (ncRNAs). ncRNAs have become increasingly important in the pathogenesis of human cancer and work as oncogenes or tumor suppressors to regulate carcinogenesis and progression. These RNAs by being involved in chromatin remodeling and modification, transcriptional regulation, and alternative splicing of pre-mRNA, as well as mRNA stability and protein translation, play a key role in tumor development and progression. Numerous studies have been performed to try to understand the dysregulation pattern of these ncRNAs in tumors and cancer stem cells (CSCs), which show robust differentiation and self-regeneration capacity. This review provides recent findings on the role of ncRNAs in glioma development and progression, particularly their effects on CSCs, thus accelerating the clinical implementation of ncRNAs as promising tumor biomarkers and therapeutic targets.

T cell exhaustion assessment algorism in tumor microenvironment predicted clinical outcomes and immunotherapy effects in glioma

Despite the recent increase in the use of immune checkpoint blockade (ICB), no ICB medications have been approved or are undergoing large-scale clinical trials for glioma. T cells, the main mediators of adaptive immunity, are important components of the tumor immune microenvironment. Depletion of T cells in tumors plays a key role in assessing the sensitivity of patients to immunotherapy. In this study, the bioinformatics approach was applied to construct T cell depletion-related risk assessment to investigate the impact of T cell depletion on prognosis and ICB response in glioma patients. The Cancer Genome Atlas (TCGA) and GSE108474 glioma cohorts and IMvigor210 immunotherapy datasets were collected, including complete mRNA expression profiles and clinical information. We used cell lines to verify the gene expression and the R 3.6.3 tool and GraphPad for bioinformatics analysis and mapping. T cell depletion in glioma patients displayed significant heterogeneity. The T cell depletion-related prognostic model was developed based on seven prognostic genes (HSPB1, HOXD10, HOXA5, SEC61G, H19, ANXA2P2, HOXC10) in glioma. The overall survival of patients with a high TEXScore was significantly lower than that of patients with a low TEXScore. In addition, high TEXScore scores were followed by intense immune responses and a more complex tumor immune microenvironment. The “hot tumors” were predominantly enriched in the high-risk group, which patients expressed high levels of suppressive immune checkpoints, such as PD1, PD-L1, and TIM3. However, patients with a low TEXScore had a more significant clinical response to immunotherapy. In addition, HSPB1 expression was higher in the U251 cells than in the normal HEB cells. In conclusion, the TEXScore related to T cell exhaustion combined with other pathological profiles can effectively assess the clinical status of glioma patients. The TEXScore constructed in this study enables the effective assessment of the immunotherapy response of glioma patients and provides therapeutic possibilities.

Long non-coding RNA OIP5-AS1 inhibition upregulates microRNA-129-5p to repress resistance to temozolomide in glioblastoma cells via downregulating IGF2BP2

OBJECTIVE

Long non-coding RNAs (lncRNAs) and miRNAs (miRNAs) participate in tumors, while the effects of lncRNA OIP5 antisense RNA 1 (OIP5-AS1) and miR-129-5p on glioblastoma (GBM) remain to be further studied. We aim to explore the role of OIP5-AS1/miR-129-5p/insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) axis in GBM progression.

METHODS

OIP5-AS1, miR-129-5p and IGF2BP2 expression in tissues was determined. Temozolomide (TMZ)-resistant GBM cells were established and transfected with relative plasmid to alter OIP5-AS1, IGF2BP2 or miR-129-5p expression. Then, the viability, proliferation, apoptosis and in vivo tumor growth were assessed. The subcellular localization of OIP5-AS1 was determined, and the binding relationships between OIP5-AS1 and miR-129-5p, and between miR-129-5p and IGF2BP2 were confirmed.

RESULTS

OIP5-AS1 and IGF2BP2 were upregulated whereas miR-129-5p was downregulated in GBM. OIP5-AS1 silencing or miR-129-5p overexpression inhibited GBM cell chemoresistance to TMZ and proliferation, and promoted cell apoptosis. MiR-129-5p downregulation or IGF2BP2 upregulation reversed the role of OIP5-AS1 silencing on GBM cells. OIP5-AS1 sponged miR-129-5p and miR-129-5p targeted IGF2BP2.

CONCLUSION

OIP5-AS1 inhibition upregulated miR-129-5p to repress resistance to TMZ in GBM cells via downregulating IGF2BP2.

lncRNA H19 promotes glioblastoma multiforme development by activating autophagy by sponging miR-491-5p

Glioblastoma multiforme (GBM) is a malignant cancer with severely poor survival, and the cells continue to thrive during hypoxia and toxic stress through autophagy. To validate the oncogenic role of long noncoding RNA H19 in GBM progression and examine whether autophagy and/or miR-491-5p participate in the process. The expression of H19 and autophagy-related genes in GBM and healthy control tissues was assessed via quantitative polymerase chain reaction. In addition, cell viability, proliferation, apoptosis and autophagy were respectively determined via cell counting kit-8 assay, clone formation assay, flow cytometry, western blotting and green fluorescent protein-microtubule-associated protein 1 light chain 3 alpha fluorescence analysis in vitro. Furthermore, a rescue assay was performed using rapamycin or miR-491-5p antagomir to examine the role of autophagy or miR-491-5p in H19-mediated regulation of proliferation and apoptosis. RNA pull-down and dual-luciferase reporter assays were employed to analyze the interaction between H19 and miR-491-5p. Additionally, tumor growth in a xenograft-bearing mouse model and autophagy in tumor mass were analyzed in vivo. The expression H19 was increased in GBM and was positively correlated with LC3 or Beclin-1. Silencing H19 inhibited growth and promoted apoptosis in GBM cells both in vitro and in vivo, and miR-491-5p was identified as one of the important mediators. H19 regulated the autophagy signaling pathway at least partly via miR-491-5p. Increased H19 expression in GBM exerts oncogenic effects by sponging miR-491-5p and enhancing autophagy. Therefore, H19 may be explored as a target for GBM therapy.

Therapy-resistant and -sensitive lncRNAs, SNHG1 and UBL7-AS1 promote glioblastoma cell proliferation

The current treatment options for glioblastoma (GBM) can result in median survival of 15-16 months only, suggesting the existence of therapy-resistant factors. Emerging evidence suggests that long non-coding RNAs (lncRNAs) play an essential role in the development of various brain tumors, including GBM. This study aimed to identify therapy-resistant and therapy-sensitive GBM associated lncRNAs and their role in GBM. We conducted a genome-wide transcriptional survey to explore the lncRNA landscape in 195 GBM brain tissues. Cell proliferation was evaluated by CyQuant assay and Ki67 immunostaining. Expression of MAD2L1 and CCNB2 was analyzed by western blotting. We identified 51 lncRNAs aberrantly expressed in GBM specimens compared with either normal brain samples or epilepsy non-tumor brain samples. Among them, 27 lncRNAs were identified as therapy-resistant lncRNAs that remained dysregulated after both radiotherapy and chemoradiotherapy; while 21 lncRNAs were identified as therapy-sensitive lncRNAs whose expressions were reversed by both radiotherapy and chemoradiotherapy. We further investigated the potential functions of the therapy-resistant and therapy-sensitive lncRNAs and demonstrated their relevance to cell proliferation. We also found that the expressions of several lncRNAs, including SNHG1 and UBL7-AS1, were positively correlated with cell-cycle genes’ expressions. Finally, we experimentally confirmed the function of a therapy-resistant lncRNA, SNHG1, and a therapy-sensitive lncRNA, UBL7-AS1, in promoting cell proliferation in GBM U138MG cells. Our in vitro results demonstrated that knockdown of SNHG1 and UBL7-AS1 showed an additive effect in reducing cell proliferation in U138MG cells.

EZH2 as a new therapeutic target in brain tumors: Molecular landscape, therapeutic targeting and future prospects

Brain tumors are responsible for high mortality and morbidity worldwide. The brain tumor treatment depends on identification of molecular pathways involved in progression and malignancy. Enhancer of zeste homolog 2 (EZH2) has obtained much attention in recent years in field of cancer therapy due to its aberrant expression and capacity in modulating expression of genes by binding to their promoter and affecting methylation status. The present review focuses on EZH2 signaling in brain tumors including glioma, glioblastoma, astrocytoma, ependymomas, medulloblastoma and brain rhabdoid tumors. EZH2 signaling mainly participates in increasing proliferation and invasion of cancer cells. However, in medulloblastoma, EZH2 demonstrates tumor-suppressor activity. Furthermore, EZH2 can regulate response of brain tumors to chemotherapy and radiotherapy. Various molecular pathways can function as upstream mediators of EZH2 in brain tumors including lncRNAs and miRNAs. Owing to its enzymatic activity, EZH2 can bind to promoter of target genes to induce methylation and affects their expression. EZH2 can be considered as an independent prognostic factor in brain tumors that its upregulation provides undesirable prognosis. Both anti-tumor agents and gene therapies such as siRNA have been developed for targeting EZH2 in cancer therapy.

Knockdown of LncRNA SNHG1 Suppresses Corneal Angiogenesis by the Regulation of miR-195-5p/VEGF-A

LncRNA SNHG1 (SNHG1) has been widely studied as the causative factor of angiogenesis and proliferative agent in gastric, lung, cervical, and hepatocellular carcinomas. However, its significance of angiogenesis and progression of corneal neovascularization (CRNV) is least understood. This study focuses on the molecular mechanisms followed by SNHG1 to establish CRNV and its angiogenesis. Bioinformatics analysis to identify potential miRNA targets of SNHG1 and vascular endothelial growth factor A (VEGF-A) was conducted using StarBase and was subsequently confirmed by the luciferase reporter assay. Relative quantitative expression of SNHG1 in human umbilical vein endothelial cells (HUVECs) was detected through qRT-PCR and western blot analysis. Cell proliferation was detected through CCK-8 assay, whereas migratory abilities of the cells were determined with transwell assay. A capillary-like tube formation assay was performed to detect the tube formation ability of the cells. Following this, relative expression of miR-195-5p and VEGF-A was determined through qRT-PCR and western blot analysis. Results from the experiments manifested upregulated levels of SNHG1 and VEGF-A in HUVECs and CRNV tissues as compared with the control group, whereas downregulated levels of miR-195-5p were measured in the CRNV tissues and HUVECs, suggesting the negative correlation between lncRNA and miRNA. Overexpressed vascular endothelial growth factor promoted cell proliferation and tube formation; however, its silencing leads to inhibition in angiogenesis and proliferation. Potential binding sites of SNHG1 showed miR-195-5p as its direct target and SNHG1 as a sponge for this miRNA. Knockdown and downregulated levels of SNHG1 showed a notable decrease and inhibition in angiogenesis and migration of CRNV cells. The study showed that SNHG1 inhibition significantly reduced cell proliferation, migration, and tube formation in HUVECs transfect with lncRNA SNHG1. Mechanistic insights into the SNHG1 showed that SNHG1 acts as a sponge for miR-195-5p and upregulates the levels of VEGF-A.

Non-coding RNAs in Regulating Tumor Angiogenesis

Non-coding RNAs (ncRNAs) are RNAs that do not encode proteins, but perform biological functions in various physiological and pathological processes, including cancer formation, inflammation, and neurological diseases. Tumor blood vessels are a key target for cancer management. A number of factors regulate the angiogenesis of malignant tumors. NcRNAs participate in the regulation of tumor angiogenesis. Abnormal expression of ncRNAs act as tumor suppressors or oncogenes to affect the development of tumors. In this review we summarized the biological functions of ncRNAs, and discussed its regulatory mechanisms in tumor angiogenesis. This article will provide new insights for the research of ncRNAs in tumor angiogenesis.

LncRNA H19 Regulates Proliferation, Apoptosis and ECM Degradation of Aortic Smooth Muscle Cells Via miR-1-3p/ADAM10 Axis in Thoracic Aortic Aneurysm

Thoracic aortic aneurysm (TAA) is a prevalent health problem worldwide. Long non-coding RNA H19was highly expressed in TAA patients, but the function and mechanism of H19 in TAA remain unknown. The expression levels of H19, microRNA-1-3p (miR-1-3p), and a disintegrin and metalloproteinase 10 (ADAM10) were detected by real-time quantitative polymerase chain reaction (RT-qPCR). Receiver operating characteristic (ROS) cure was performed to evaluate the diagnostic value of H19 on TAA patients. Proliferation and apoptosis were detected by Cell Counting Kit-8 (CCK-8), colony formation, and flow cytometry. Protein levels of proliferating cell nuclear antigen (PCNA), Cleaved-caspase 3 (Cleaved-cas3), Cleaved-caspase 9 (Cleaved-cas9), Collagen I, Collagen III, and ADAM10 were tested by western blot assay. The binding relationship between miR-1-3p and H19 or ADAM10 was predicted by LncBase Predicted v.2 or Starbase, and verified by the dual-luciferase reporter, RNA pull-down assay, and RNA Immunoprecipitation (RIP) assays. H19 was increased in TAA aorta tissues and serum and vascular smooth muscle cell (VSMC), and hindered proliferation as well as promoted apoptosis and extracellular matrix (ECM) degradation of VSMC. Moreover, miR-1-3p was decreased, and ADAM10 was upregulated in TAA aorta tissues and VSMC. The mechanical analysis confirmed that H19 affected ADAM10 expression by targeting miR-1-3p. Our results indicated that H19 inhibited proliferation, and accelerated apoptosis and ECM degradation of VSMC, providing an underlying lncRNA-targeted therapy for TAA treatment.

LncRNA H19: A novel oncogene in multiple cancers

Long non-coding RNAs (lncRNAs) are a series of non-coding RNAs that lack open reading frameworks. Accumulating evidence suggests important roles for lncRNAs in various diseases, including cancers. Recently, lncRNA H19 (H19) became a research focus due to its ectopic expression in human malignant tumors, where it functioned as an oncogene. Subsequently, H19 was confirmed to be involved in tumorigenesis and malignant progression in many tumors and had been implicated in promoting cell growth, invasion, migration, epithelial-mesenchymal transition, metastasis, and apoptosis. H19 also sequesters some microRNAs, facilitating a multilayer molecular regulatory mechanism. In this review, we summarize the abnormal overexpression of H19 in human cancers, which suggests wide prospects for further research into the diagnosis and treatment of cancers.

Cardiac pathologies in mouse loss of imprinting models are due to misexpression of H19 long noncoding RNA

Maternal loss of imprinting (LOI) at the H19/IGF2 locus results in biallelic IGF2 and reduced H19 expression and is associated with Beckwith--Wiedemann syndrome (BWS). We use mouse models for LOI to understand the relative importance of Igf2 and H19 mis-expression in BWS phenotypes. Here we focus on cardiovascular phenotypes and show that neonatal cardiomegaly is exclusively dependent on increased Igf2. Circulating IGF2 binds cardiomyocyte receptors to hyperactivate mTOR signaling, resulting in cellular hyperplasia and hypertrophy. These Igf2-dependent phenotypes are transient: cardiac size returns to normal once Igf2 expression is suppressed postnatally. However, reduced H19 expression is sufficient to cause progressive heart pathologies including fibrosis and reduced ventricular function. In the heart, H19 expression is primarily in endothelial cells (ECs) and regulates EC differentiation both in vivo and in vitro. Finally, we establish novel mouse models to show that cardiac phenotypes depend on H19 lncRNA interactions with Mirlet7 microRNAs.

Emerging roles of a pivotal lncRNA SBF2-AS1 in cancers

Long non-coding RNAs refer to transcripts over 200 nt in length that lack the ability to encode proteins, which occupy the majority of the genome and play a crucial role in the occurrence and development of human diseases, especially cancers. SBF2-AS1, a newly identified long non-coding RNA, has been verified to be highly expressed in diversiform cancers, and is involved in processes promoting tumorigenesis, tumor progression and tumor metastasis. Moreover, upregulation of SBF2-AS1 expression was significantly related to disadvantageous clinicopathologic characteristics and indicated poor prognosis. In this review, we comprehensively summarize the up-to-date knowledge of the detailed mechanisms and underlying functions of SBF2-AS1 in diverse cancer types, highlighting the potential of SBF2-AS1 as a diagnostic and prognostic biomarker and even a therapeutic target.

Long Non-Coding RNAs in Diagnosis, Treatment, Prognosis, and Progression of Glioma: A State-of-the-Art Review

Glioma is the most common malignant central nervous system tumor with significant mortality and morbidity. Despite considerable advances, the exact molecular pathways involved in tumor progression are not fully elucidated, and patients commonly face a poor prognosis. Long non-coding RNAs (lncRNAs) have recently drawn extra attention for their potential roles in different types of cancer as well as non-malignant diseases. More than 200 lncRNAs have been reported to be associated with glioma. We aimed to assess the roles of the most investigated lncRNAs in different stages of tumor progression and the mediating molecular pathways in addition to their clinical applications. lncRNAs are involved in different stages of tumor formation, invasion, and progression, including regulating the cell cycle, apoptosis, autophagy, epithelial-to-mesenchymal transition, tumor stemness, angiogenesis, the integrity of the blood-tumor-brain barrier, tumor metabolism, and immunological responses. The well-known oncogenic lncRNAs, which are upregulated in glioma, are H19, HOTAIR, PVT1, UCA1, XIST, CRNDE, FOXD2-AS1, ANRIL, HOXA11-AS, TP73-AS1, and DANCR. On the other hand, MEG3, GAS5, CCASC2, and TUSC7 are tumor suppressor lncRNAs, which are downregulated. While most studies reported oncogenic effects for MALAT1, TUG1, and NEAT1, there are some controversies regarding these lncRNAs. Expression levels of lncRNAs can be associated with tumor grade, survival, treatment response (chemotherapy drugs or radiotherapy), and overall prognosis. Moreover, circulatory levels of lncRNAs, such as MALAT1, H19, HOTAIR, NEAT1, TUG1, GAS5, LINK-A, and TUSC7, can provide non-invasive diagnostic and prognostic tools. Modulation of expression of lncRNAs using antisense oligonucleotides can lead to novel therapeutics. Notably, a profound understanding of the underlying molecular pathways involved in the function of lncRNAs is required to develop novel therapeutic targets. More investigations with large sample sizes and increased focus on in-vivo models are required to expand our understanding of the potential roles and application of lncRNAs in glioma.

Long Noncoding RNA PVT1 Promotes Stemness and Temozolomide Resistance through miR-365/ELF4/SOX2 Axis in Glioma

Long non-coding RNA (lncRNA) are a class of non-coding RNAs demonstrated to play pivotal roles in regulating tumor progression. Therefore, deciphering the regulatory role of lncRNA in the development of glioma may offer a promising therapeutic target for treatment of glioma. We performed RT-qPCR analysis on the expression of lncRNA plasmacytoma variant translocation 1 (PVT1) and miR-365 in glioma tissues and cell lines. Cell proliferation and viability was assessed with CCK8 assay. Cell migration was assessed by wound healing assay. Transwell assay was used to assess cell invasion capacity. Expression of CD133+ cells was detected by flow cytometry. Western blot assay was used to detection the expression of ELF4 and stemness-related protein SOX2, Oct4 and Nanog. Bioinformatics and dual-luciferase assay were used to predict and validate the interaction between PVT1 and miR-365. Elevated PVT1 expression was observed in glioma tissues and cells. Knockdown of PVT1 and overexpression of miR-365 inhibited proliferation, migration, invasion and promoted stemness and Temozolomide (TMZ) resistance of glioma cells. PVT1 regulated ELF4 expression by competitively binds to miR-365. PVT1 regulated the stemness and sensitivity of TMZ of glioma cells through miR-365/ELF4/SOX2 axis. This study identified that PVT1 promoted glioma stemness through miR-365/ELF4/SOX2 axis.

Epigenetic regulation of cancer stem cell formation and maintenance

Cancerous tumours contain a rare subset of cells with stem-like properties that are termed cancer stem cells (CSCs). CSCs are defined by their ability to divide both symmetrically and asymmetrically, to initiate new tumour growth and to tolerate the foreign niches required for metastatic dissemination. Accumulating evidence suggests that tumours arise from cells with stem-like properties, the generation of CSCs is therefore likely to be an initiatory event in carcinogenesis. Furthermore, CSCs in established tumours exist in a dynamic and plastic state, with nonstem tumour cells thought to be capable of de-differentiation to CSCs. The regulation of the CSC state both during tumour initiation and within established tumours is a desirable therapeutic target and is mediated by epigenetic factors. In this review, we will explore the epigenetic parallels between induced pluripotency and the generation of CSCs, and discuss how the epigenetic regulation of CSCs opens up novel opportunities for therapeutic intervention.

Insights into how H19 works in glioma cells. A review article

Glioblastoma is a highly aggressive brain tumor and considered to be the most common primary one. Recurrence after treatment is a significant problem, with a survival rate after one year of about 39.7%. The recurrence of GBM is linked to different cellular pathways and molecular signaling. Long non-coding RNA (LncRNA) comprises more than 200 nucleotides and is suggested to play a role in controlling genes that regulate the cell cycle, apoptosis and cellular growth in various tissues. Little is known about LncRNA compared to microRNAs, which are extensively studied in the literature. H19 is one of the most plentiful and conserved transcripts suggested to be involved in mammalian development and tumorigenesis. H19 is one of the LncRNA members transcribed by RNA polymerase II, spliced and polyadenylated, and the product is transferred to the cytoplasm without translation. HI9 maps to 1lp15, a region thought to be relevant to some childhood tumors as embryonal rhabdomyosarcoma and Wilm's Tumor. In these tumors, the analysis of the 11p15 locus showed loss of heterozygosity which is a feature associated with the tumor-suppressing activity. However, the role played by H19 in GBM is still enigmatic and needs further extensive evaluation. Uncovering the hidden role of such molecules in the pathogenesis in glioma will help tailor new targeted therapies that may affect the prognosis and survival of GBM.

LINC01158 works as an oncogene in glioma via sponging miR-6734-3p to boost CENPK expression

BACKGROUND

Long non-coding RNAs (lncRNAs) have been certified to play vital biological functions in glioma and have received considerable attention in the recent literature. Nonetheless, the role of LINC01158 in glioma remains to be elucidated.

METHODS

qRT-PCR, western blot and GEPIA database were applied for reporting the expression of CENPK and LINC01158 in glioma and the correlation between LINC01158 and CENPK expression. EdU, colony formation, CCK-8, caspase-3 activity and TUNEL assays probed the impacts of LINC01158 on glioma cell growth. Subcellular fractionation and FISH assays revealed the cellular distribution of LINC01158. Luciferase reporter and RIP assays examined ceRNA network of LINC01158, CENPK and miR-6734-3p.

RESULTS

LINC01158 and CENPK were both overexpressed in glioma and a positive regulation of LINC01158 on CENPK was corroborated. LINC01158 served a pro-proliferative and anti-apoptotic part in glioma by sponging miR-6734-3p to augment CENPK.

CONCLUSION

LINC01158 enhances CENPK by serving as sponge for miR-6734-3p to facilitate glioma development, proposing LINC01158 as a new player in glioma.

Long non-coding RNAs in brain tumors: roles and potential as therapeutic targets

Brain tumors are associated with adverse outcomes despite improvements in radiation therapy, chemotherapy, and photodynamic therapy. However, treatment approaches are evolving, and new biological phenomena are being explored to identify the appropriate treatment of brain tumors. Long non-coding RNAs (lncRNAs), a type of non-coding RNA longer than 200 nucleotides, regulate gene expression at the transcriptional, post-transcriptional, and epigenetic levels and are involved in a variety of biological functions. Recent studies on lncRNAs have revealed their aberrant expression in various cancers, with distinct expression patterns associated with their instrumental roles in cancer. Abnormal expression of lncRNAs has also been identified in brain tumors. Here, we review the potential roles of lncRNAs and their biological functions in the context of brain tumors. We also summarize the current understanding of the molecular mechanisms and signaling pathways related to lncRNAs that may guide clinical trials for brain tumor therapy.

Long noncoding RNA GAS8-AS1: A novel biomarker in human diseases

Long non-coding RNAs (lncRNAs) represent a group of ncRNAs with more than 200 nucleotides. These RNAs can specifically regulate gene expression at both the transcriptional and the post-transcriptional levels, and increasing evidence indicates that they play vital roles in a variety of disease-related cellular processes. The lncRNA GAS8 antisense RNA 1 (GAS8-AS1, also known as C16orf3) is located in the second intron of GAS8 and has been reported to be both abnormally expressed in several diseases and closely correlated with many clinical characteristics. GAS8-AS1 has been shown to affect many biological functions, including cell proliferation, migration, invasiveness, and autophagy using several signaling pathways. In this review, we have summarized current studies on GAS8-AS1 roles in disease and discuss its potential clinical utility. GAS8-AS1 may be a promising biomarker for both diagnoses and prognoses, and a novel target for many disease therapies.

The Molecular and Microenvironmental Landscape of Glioblastomas: Implications for the Novel Treatment Choices

Glioblastoma (GBM) is the most frequent and aggressive primary central nervous system tumor. Surgery followed by radiotherapy and chemotherapy with alkylating agents constitutes standard first-line treatment of GBM. Complete resection of the GBM tumors is generally not possible given its high invasive features. Although this combination therapy can prolong survival, the prognosis is still poor due to several factors including chemoresistance. In recent years, a comprehensive characterization of the GBM-associated molecular signature has been performed. This has allowed the possibility to introduce a more personalized therapeutic approach for GBM, in which novel targeted therapies, including those employing tyrosine kinase inhibitors (TKIs), could be employed. The GBM tumor microenvironment (TME) exerts a key role in GBM tumor progression, in particular by providing an immunosuppressive state with low numbers of tumor-infiltrating lymphocytes (TILs) and other immune effector cell types that contributes to tumor proliferation and growth. The use of immune checkpoint inhibitors (ICIs) has been successfully introduced in numerous advanced cancers as well as promising results have been shown for the use of these antibodies in untreated brain metastases from melanoma and from non-small cell lung carcinoma (NSCLC). Consequently, the use of PD-1/PD-L1 inhibitors has also been proposed in several clinical trials for the treatment of GBM. In the present review, we will outline the main GBM molecular and TME aspects providing also the grounds for novel targeted therapies and immunotherapies using ICIs for GBM.

LncRNA H19 Promotes Cell Proliferation, Migration, and Angiogenesis of Glioma by Regulating Wnt5a/β-Catenin Pathway via Targeting miR-342

Glioma is the most common malignant brain tumor and long non-coding RNAs (lncRNAs) have been reported to play an important role in the growth and angiogenesis of glioma. However, the potential mechanisms of lncRNA H19 in glioma remain unclear. In the present study, the effects of lncRNA H19 on glioma cell proliferation, migration, and angiogenesis were evaluated. The expression levels of H19, miR-342, and Wnt5a in glioma tissues and cells were detected by RT-qPCR or Western blotting. Dual luciferase reporter assay confirmed the interaction between H19, miR-342, and Wnt5a. Cell proliferation, migration, and angiogenesis were analyzed by colony formation, transwell, and tube formation assays, respectively. IHC was performed to test the angiogenesis-related factor CD31. H19 and Wnt5a expression were remarkably upregulated in glioma tissues and cells, whereas miR-342 expression was downregulated. Moreover, functional analysis confirmed that knockdown of H19 or overexpression of miR-342 suppressed glioma cell proliferation, migration, and angiogenesis in vitro. Besides, H19 was found to directly target miR-342 to promote Wnt5a expression and activate β-catenin pathway in glioma cells. Moreover, suppression of miR-342 or overexpression of Wnt5a reversed the inhibitory effect of sh-H19 on glioma growth and metastasis. Additionally, we verified that H19 promoted glioma cell proliferation, migration, and angiogenesis via miR-342/Wnt5a/β-catenin axis in vivo. H19 regulates glioma cell growth and metastasis through miR-342 to mediate Wnt5a/β-catenin signaling pathway, which provides new therapeutic targets for glioma treatment.

Effect of alkylglycerone phosphate synthase on the expression levels of lncRNAs in glioma cells and its functional prediction

Alkylglycerone phosphate synthase (AGPS) is a key enzyme for ether ester synthesis and acts as an oncogene in malignant tumors. The present study aimed to investigate the effect of AGPS silencing on the expression levels of long non-coding RNAs (lncRNAs) and the co-expression with mRNAs in glioma U251 cells using microarray analysis. Furthermore, the underlying biological functions of crucial lncRNAs identified were investigated. It was discovered that in vitro U251 cell proliferation was suppressed following the genetic silencing of AGPS. Differentially expressed lncRNAs and mRNAs in U251 cells were sequenced following AGPS silencing. The results from the Gene Ontology analysis identified that the co-expressed mRNAs were mainly involved in biological processes, such as 'cellular response to hypoxia', 'extracellular matrix organization' and 'PERK-mediated unfolded protein response'. In addition, Kyoto Encyclopedia of Genes and Genomes signaling pathway enrichment analysis revealed that the co-expressed mRNAs were the most enriched in the 'AGE/RAGE signaling pathway in diabetic conditions'. Additionally, the PI3K/Akt and epidermal growth factor receptor signaling pathways serve important roles in tumor processes, for example carcinogenesis and angiogenesis. Furthermore, it was identified that the lncRNA AK093732 served a vital role in the regulatory network and the core pathway in this network regulated by this lncRNA was discovered to be the 'Cytokine-cytokine receptor interaction'. In conclusion, the findings of the present study suggested that AGPS may affect cell proliferation and the degree of malignancy. In addition, the identified lncRNAs and their co-expressed mRNAs screened using microarrays may have significant biological effects in the occurrence, development and metastasis of glioma, and thus may be novel markers of glioma.

Non-coding RNAs in Brain Tumors, the Contribution of lncRNAs, circRNAs, and snoRNAs to Cancer Development-Their Diagnostic and Therapeutic Potential

Brain tumors are one of the most frightening ailments that afflict human beings worldwide. They are among the most lethal of all adult and pediatric solid tumors. The unique cell-intrinsic and microenvironmental properties of neural tissues are some of the most critical obstacles that researchers face in the diagnosis and treatment of brain tumors. Intensifying the search for potential new molecular markers in order to develop new effective treatments for patients might resolve this issue. Recently, the world of non-coding RNAs (ncRNAs) has become a field of intensive research since the discovery of their essential impact on carcinogenesis. Some of the most promising diagnostic and therapeutic regulatory RNAs are long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), and small nucleolar RNAs (snoRNAs). Many recent reports indicate the important role of these molecules in brain tumor development, as well as their implications in metastasis. In the following review, we summarize the current state of knowledge about regulatory RNAs, namely lncRNA, circRNAs, and snoRNAs, and their impact on the development of brain tumors in children and adults with particular emphasis on malignant primary brain tumors-gliomas and medulloblastomas (MB). We also provide an overview of how these different ncRNAs may act as biomarkers in these tumors and we present their potential clinical implications.

SNHG17 drives malignant behaviors in astrocytoma by targeting miR-876-5p/ERLIN2 axis

Background

Astrocytoma is a common tumor type in primary central nervous system and has a high death rate around the world. Aberrant expression of long non-coding RNAs (lncRNAs) has been introduced by emerging studies to result in the development of diverse cancers.

Methods

RT-qPCR examined the expression of SNHG17, miR-876-5p and ERLIN2, and western blot evaluated ERLIN2 protein level. RNA pull down and luciferase reporter assays illustrated the relationships between SNHG17 and its downstream molecules.

Results

SNHG17 was up-regulated in astrocytoma cells. Moreover, SNHG17 silence could repress the proliferation, migration and invasion of astrocytoma cells. Besides, miR-876-5p was selected out as a downstream molecule of SNHG17 in astrocytoma. ERLIN2 was determined to be targeted by miR-876-5p. ERLIN2 mRNA and protein levels were lessened by miR-876-5p overexpression and SNHG17 silence. Additionally, miR-876-5p overexpression decelerated the biological processes of astrocytoma cells, so did ERLIN2 knockdown. More importantly, the impacts of SNHG17 down-regulation on the malignant behaviors of astrocytoma cells were counteracted by overexpressed ERLIN2 or inhibited miR-876-5p.

Conclusions

SNHG17 could induce the progression of astrocytoma by sponging miR-876-5p to elevate the expression of ERLIN2. This study indicated that SNHG17 has a high potential to be a therapeutic target for astrocytoma.

Roles of long non-coding RNAs in the hallmarks of glioma

Glioma is one of the most common types of tumor of the central nervous system. Due to the aggressiveness and invasiveness of high-level gliomas, the survival time of patients with these tumors is short, at ~15 months, even after combined treatment with surgery, radiotherapy and/or chemotherapy. Recently, a number of studies have demonstrated that long non-coding RNA (lncRNAs) serve crucial roles in the multistep development of human gliomas. Gliomas acquire numerous biological abilities during multistep development that collectively constitute the hallmarks of glioma. Thus, in this review, the roles of lncRNAs associated with glioma hallmarks and the current and future prospects for their development are summarized.

Coding of Glioblastoma Progression and Therapy Resistance through Long Noncoding RNAs

Glioblastoma is the most aggressive and lethal primary brain malignancy, with an average patient survival from diagnosis of 14 months. Glioblastoma also usually progresses as a more invasive phenotype after initial treatment. A major step forward in our understanding of the nature of glioblastoma was achieved with large-scale expression analysis. However, due to genomic complexity and heterogeneity, transcriptomics alone is not enough to define the glioblastoma “fingerprint”, so epigenetic mechanisms are being examined, including the noncoding genome. On the basis of their tissue specificity, long noncoding RNAs (lncRNAs) are being explored as new diagnostic and therapeutic targets. In addition, growing evidence indicates that lncRNAs have various roles in resistance to glioblastoma therapies (e.g., MALAT1, H19) and in glioblastoma progression (e.g., CRNDE, HOTAIRM1, ASLNC22381, ASLNC20819). Investigations have also focused on the prognostic value of lncRNAs, as well as the definition of the molecular signatures of glioma, to provide more precise tumor classification. This review discusses the potential that lncRNAs hold for the development of novel diagnostic and, hopefully, therapeutic targets that can contribute to prolonged survival and improved quality of life for patients with glioblastoma.

Current advances of long non-coding RNAs mediated by wnt signaling in glioma

Glioma is the most common and aggressive brain tumor in the central nervous system (CNS), in which Wnt signaling pathway has been verified to play a pivotal role in regulating the initiation and progression. Currently, numerous studies have indicated that long non-coding RNAs (lncRNAs) have critical functions across biological processes including cell proliferation, colony formation, migration, invasion and apoptosis via Wnt signaling pathway in glioma. This review depicts canonical and non-canonical Wnt/β-catenin signaling pathway properties and relative processing mechanisms in gliomas, and summarizes the function and regulation of lncRNAs mediated by Wnt signaling pathway in the development and progression of glioma. Ultimately, we hope to seek out promising biomarkers and reliable therapeutic targets for glioma.

Exosomal taurine up-regulated 1 promotes angiogenesis and endothelial cell proliferation in cervical cancer

Emerging evidence had highlighted that exosomes could mediate cell-cell communication in human cancerous development via transferring the various molecular cargos, including long non-coding RNA (lncRNA). Taurine up-regulated 1 (TUG1) was previously reported as an oncogenic lncRNA in cervical cancer (CC) via facilitating cell proliferation and other vital biological behaviors. Nevertheless, the presence of TUG1 in exosomes and the functional regulation of exosomal TUG1 in CC are still elusive. The current study aimed at the communication between CC cell lines and endothelial cell-mediated by exosomes, as well as the roles of exosomes derived from CC cells and exosomal TUG1 in affecting angiogenesis. Initially, it was found that TUG1 expression was upregulated in both CC cells and their secreted exosomes. TUG1 was transferred from CC cells to recipient human umbilical vein endothelial cells (HUVECs) in the exosomes way. Interestingly, TUG1 depletion impaired the exosomes-mediated proangiogenic potential of HUVECs by modulating certain key angiogenesis-related genes. In addition, exosomal TUG1 contributed to HUVECs proliferation through suppressing caspase-3 activity and impacting apoptosis-related proteins. Collectively, we identified a new exosomes-mediated molecular mechanism by which CC cells transferred TUG1 via exosomes to recipient HUVECs, thus promoting angiogenesis, providing a promising target for early diagnosis of CC.

Long non-coding RNA H19, a novel therapeutic target for pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with high mortality, which threats peoples’ health. Unfortunately, the pathogenesis of PDAC remains unclear. Recent studies have indicated that long non-coding RNAs (lncRNAs) can regulate the development and progression of malignant tumors through varying mechanisms. LncRNA H19 has a unique expression profile and can act as a sponger of specific miRNAs to regulate the pathogenic process of many diseases, including PDAC and several other types of cancers. Here, we review the research approaches to understanding the regulatory role of H19 and potential mechanisms in the progression of PDAC and other types of cancers and diseases. These studies suggest that H19 may be a novel therapeutic target for PDAC and our findings may open new revenues for scientific researches and development of valuable therapies for these diseases in the future.

Macrophages-induced long noncoding RNA H19 up-regulation triggers and activates the miR-193b/MAPK1 axis and promotes cell aggressiveness in hepatocellular carcinoma

Dysregulation of long noncoding RNA (lncRNA) H19 has been implicated in hepatocellular carcinoma (HCC), but the concrete regulatory mechanism is lack of research. We mined gene expression profiles of 457 HCC samples from TCGA and TJMUCH cohorts and further validated in 64 FFPE HCC tissues. LncRNA H19 overexpression in situ was significantly correlated with poor prognosis of HCC patients, which induced EMT, promoted stemness and accelerated invasion of HCC cells in vitro. Co-expression network analysis indicated lncRNA H19 negatively correlated with miR-193b and positively correlated with MAPK1 gene, which implicated that lncRNA H19 served as a sponge molecule to hijack miR-193b and protect MAPK1. Forced overexpression of H19 attenuated miR-193b-mediated inhibition on multiple driver oncogenes (EGFR, KRAS, PTEN and IGF1R) and MAPK1 gene, thus triggered EMT and stem cell transformation in HCC. LncRNA H19 positively correlated with CD68 ⁺ TAMs in situ. TAMs-induced lncRNA H19 promotes HCC aggressiveness via triggering and activating the miR-193b/MAPK1 axis, mediates the crosstalk between HCC and immunological microenvironment, and causes poor clinical outcomes. LncRNA H19 is a valuable predictive biomarker and potential therapeutic target in HCC.

H19 lncRNA: Roles in tumorigenesis

H19 is a long non-coding RNA [lncRNA] which was firstly described as an oncofetal transcript. The imprinted gene is normally expressed from the maternal allele. However, this pattern of imprinting is dysregulated in several cancers leading to aberrant up-regulation of H19 in malignant tissues. Several studies have utilized this aberrant expression pattern to find specific biomarkers for detection of cancer in tumoral tissues or peripheral blood. Moreover, single nucleotide polymorphisms within H19 have been associated with risk of oral squamous cell carcinoma, hepatocellular carcinoma, breast cancer, bladder cancer, gastric cancer and colorectal cancer. Taken together, H19 is regarded as a biomarker for cancer and a putative therapeutic target in these human disorders.

Functional Roles of Long Non-Coding RNAs (LncRNAs) in Glioma Stem Cells

Glioma, the most common and aggressive type of brain tumor, has a poor prognosis. Glioma stem cells (GSCs) are thought to be responsible for glioma genesis, proliferation, resistance to chemoradiotherapy, and recurrence. Long non-coding RNAs (lncRNAs) have been viewed as a prospective novel target in glioma therapy in recent years due to their functional roles in GSC biological processes. However, how lncRNAs interact with GSCs and the underlining mechanisms associated with these interactions are not yet clear. In this review, we briefly illustrate recent advancements in the functional roles of lncRNA and their potential mechanisms in GSCs.

Impact of four lncRNA polymorphisms (rs2151280, rs7763881, rs1136410, and rs3787016) on glioma risk and prognosis: A case-control study

Long noncoding RNA (lncRNA) polymorphisms are reportedly in connection with tumor susceptibility and prognosis. Glioma is one of the most aggressive and common cancers of the central nervous system. This study aimed to investigate the relationship between four lncRNA variants and glioma susceptibility and prognosis in a Chinese Han population. Sequenom Mass-ARRAY was used to genotype 605 patients with glioma and 1300 cancer-free individuals. Odds ratios or hazard ratios and related 95% confidence intervals were calculated to estimate the correlations. Logistic and Cox regression models, log-rank tests, and Kaplan-Meier curves were used for the statistical analysis. Six inheritance models showed that ANRIL rs2151280 variant genotype (A>G) was related to the susceptibility of glioma, while the other three lncRNAs showed no association. Patients treated with temozolomide or nimustine had better progression-free survival (PFS) and overall survival (OS) than those treated with platinum. Besides, patients aged older than 40 years showed a poorer OS. The Cox multivariate analysis revealed that the rs1136410 GG genotype (A>G) was beneficial for OS and PFS. The Kaplan-Meier analyses indicated that rs1136410 A>G and the rs7763881 A>C were associated with longer OS. ANRIL rs2151280 variant genotype might increase susceptibility of glioma. In addition, PARP1 rs1136410 variant genotype could be beneficial for the overall survival of patients with glioma. More research data are needed to further validate our results.

Diabetic Retinopathy, lncRNAs, and Inflammation: A Dynamic, Interconnected Network

Diabetic retinopathy (DR) is reaching epidemic levels globally due to the increase in prevalence of diabetes mellitus (DM). DR also has detrimental effects to quality of life, as it is the leading cause of blindness in the working-age population and the most common cause of vision loss in individuals with DM. Over several decades, many studies have recognized the role of inflammation in the development and progression of DR; however, in recent years, accumulating evidence has also suggested that non-coding RNAs, especially long non-coding (lncRNAs), are aberrantly expressed in diabetes and may play a putative role in the development and progression of DR through the modulation of gene expression at the transcriptional, post-transcriptional, or epigenetic level. In this review, we will first highlight some of the key inflammatory mediators and transcription factors involved in DR, and we will then introduce the critical roles of lncRNAs in DR and inflammation. Following this, we will discuss the implications of lncRNAs in other epigenetic mechanisms that may also contribute to the progression of inflammation in DR.

Long non‑coding RNA DLEU1 promotes cell proliferation of glioblastoma multiforme

Glioblastoma multiforme (GBM) is the most common malignant tumor with high morbidity and mortality. This study investigated the role of long non‑coding RNAs (lncRNAs) in glioblastomagenesis progression. Using the GSE2223 and GSE59612 datasets, and RNA sequencing data of GBM from The Cancer Genome Atlas, differentially expressed (DE) genes including DE messenger RNAs (DEmRNAs) and DElncRNAs between GBM and normal controls were identified. Based on the competing endogenous RNA hypothesis, DElncRNA‑micro RNA (miRNA)‑DEmRNA interactions were obtained by target gene prediction. Gene Ontology (GO) and Kyoto Encyclopedia of Gene and Genomes pathway analysis of DEmRNAs in the DElncRNA‑miRNA‑DEmRNA network was performed. Expression and function analyses of DElncRNAs were performed by reverse transcription‑polymerase chain reaction (RT‑PCR) and an established viability assay, respectively. In total, 712 DE genes were identified. Significant upregulation of lncRNA deleted in lymphocytic leukemia 1 (DLEU1) was revealed in GBM and a number of other types of cancer. DLEU1 interacted with 315 miRNAs and 105 DEmRNAs. The DEmRNAs were mainly enriched in tumorigenesis‑associated GO terms (angiogenesis, positive regulation of cell proliferation, positive regulation of fibroblast apoptotic processes and regulation of neutrophil migration) and pathways (Hippo signaling pathway, cancer pathways, and Wnt signaling pathway). Correlation analysis revealed that mRNA TNF receptor associated factor 4 (TRAF4) was associated with DLEU1 expression. RT‑PCR demonstrated that the expression levels of DLEU1 and TRAF4 were increased in GBM tissues. Small interfering RNA demonstrated that silencing DLEU1 downregulated TRAF4. The viability of GBM cells was significantly decreased following RNA interference with DLEU1 and TRAF4 production. The results demonstrate that DLEU1 and TRAF4 is highly expressed in GBM tissues and promotes proliferation of GBM cells. It may act as a competing endogenous RNA and influence tumorigenesis of GBM.

LINC01579 promotes cell proliferation by acting as a ceRNA of miR-139-5p to upregulate EIF4G2 expression in glioblastoma

Glioblastoma (GBM), a malignant and lethal tumor, remains a big threat to human health and life. Increasing explorations have confirmed that long noncoding RNAs are involved in the tumorigenesis and development of multiple cancers. Nevertheless, the regulatory mechanism of (long intergenic nonprotein coding RNA 1579 LINC01579) in GBM remains to be investigated. In this study, the expression of LINC01579 was upregulated in GBM cells and LINC01579 knockdown inhibited cell proliferation as well as promoted cell apoptosis. Additionally, LINC01579 acted as a sponge for miR-139-5p in GBM and eukaryotic translation initiation factor 4 gamma 2 (EIF4G2) was found to be a downstream target of miR-139-5p. Furthermore, the positive correlation of LINC01579 and EIF4G2 as well as the converse correlation between miR-139-5p and LINC01579 (or EIF4G2) were revealed by the experiments. Based on rescue assays, EIF4G2 overexpression or miR-139-5p inhibitor partially recovered the function of LINC01579 knockdown on cell proliferation and apoptosis. In summary, the results of this study verified that LINC01579 modulated cell proliferation and cell apoptosis in GBM by competitively binding with miR-139-5p to regulate EIF4G2, which provided a new clue to figure out potential therapy for patients suffered from GBM.

Exosomal transfer of long non-coding RNA SBF2-AS1 enhances chemoresistance to temozolomide in glioblastoma

Background

Acquired drug resistance is a constraining factor in clinical treatment of glioblastoma (GBM). However, the mechanisms of chemoresponsive tumors acquire therapeutic resistance remain poorly understood. Here, we aim to investigate whether temozolomide (TMZ) resistance of chemoresponsive GBM was enhanced by long non-coding RNA SBF2 antisense RNA 1 (lncRNA SBF2-AS1) enriched exosomes.

Method

LncSBF2-AS1 level in TMZ-resistance or TMZ-sensitive GBM tissues and cells were analyzed by qRT-PCR and FISH assays. A series of in vitro assay and xenograft tumor models were performed to observe the effect of lncSBF2-AS1 on TMZ-resistance in GBM. CHIP assay were used to investigate the correlation of SBF2-AS1 and transcription factor zinc finger E-box binding homeobox 1 (ZEB1). Dual-luciferase reporter, RNA immunoprecipitation (RIP), immunofluorescence and western blotting were performed to verify the relation between lncSBF2-AS1, miR-151a-3p and XRCC4. Comet assay and immunoblotting were performed to expound the effect of lncSBF2-AS1 on DNA double-stand break (DSB) repair. A series of in vitro assay and intracranial xenografts tumor model were used to determined the function of exosomal lncSBF2-AS1.

Result

It was found that SBF2-AS1 was upregulated in TMZ-resistant GBM cells and tissues, and overexpression of SBF2-AS1 led to the promotion of TMZ resistance, whereas its inhibition sensitized resistant GBM cells to TMZ. Transcription factor ZEB1 was found to directly bind to the SBF2-AS1 promoter region to regulate SBF2-AS1 level and affected TMZ resistance in GBM cells. SBF2-AS1 functions as a ceRNA for miR-151a-3p, leading to the disinhibition of its endogenous target, X-ray repair cross complementing 4 (XRCC4), which enhances DSB repair in GBM cells. Exosomes selected from temozolomide-resistant GBM cells had high levels of SBF2-AS1 and spread TMZ resistance to chemoresponsive GBM cells. Clinically, high levels of lncSBF2-AS1 in serum exosomes were associated with poor response to TMZ treatment in GBM patients.

Conclusion

We can conclude that GBM cells remodel the tumor microenvironment to promote tumor chemotherapy-resistance by secreting the oncogenic lncSBF2-AS1-enriched exosomes. Thus, exosomal lncSBF2-AS1 in human serum may serve as a possible diagnostic marker for therapy-refractory GBM.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1139-6) contains supplementary material, which is available to authorized users.

Oligonucleotide Therapeutics as a New Class of Drugs for Malignant Brain Tumors: Targeting mRNAs, Regulatory RNAs, Mutations, Combinations, and Beyond

Malignant brain tumors are rapidly progressive and often fatal owing to resistance to therapies and based on their complex biology, heterogeneity, and isolation from systemic circulation. Glioblastoma is the most common and most aggressive primary brain tumor, has high mortality, and affects both children and adults. Despite significant advances in understanding the pathology, multiple clinical trials employing various treatment strategies have failed. With much expanded knowledge of the GBM genome, epigenome, and transcriptome, the field of neuro-oncology is getting closer to achieve breakthrough-targeted molecular therapies. Current developments of oligonucleotide chemistries for CNS applications make this new class of drugs very attractive for targeting molecular pathways dysregulated in brain tumors and are anticipated to vastly expand the spectrum of currently targetable molecules. In this chapter, we will overview the molecular landscape of malignant gliomas and explore the most prominent molecular targets (mRNAs, miRNAs, lncRNAs, and genomic mutations) that provide opportunities for the development of oligonucleotide therapeutics for this class of neurologic diseases. Because malignant brain tumors focally disrupt the blood-brain barrier, this class of diseases might be also more susceptible to systemic treatments with oligonucleotides than other neurologic disorders and, thus, present an entry point for the oligonucleotide therapeutics to the CNS. Nevertheless, delivery of oligonucleotides remains a crucial part of the treatment strategy. Finally, synthetic gRNAs guiding CRISPR-Cas9 editing technologies have a tremendous potential to further expand the applications of oligonucleotide therapeutics and take them beyond RNA targeting.

Role of flow-sensitive microRNAs and long noncoding RNAs in vascular dysfunction and atherosclerosis

Atherosclerosis is the primary underlying cause of myocardial infarction, ischemic stroke, and peripheral artery disease. The disease preferentially occurs in arterial regions exposed to disturbed blood flow, in part, by altering expression of flow-sensitive coding- and non-coding genes. In this review, we summarize the role of noncoding RNAs, [microRNAs (miRNAs) and long noncoding RNAs(lncRNAs)], as regulators of gene expression and outline their relationship to the pathogenesis of atherosclerosis. While miRNAs are small noncoding genes that post-transcriptionally regulate gene expression by targeting mRNA transcripts, the lncRNAs regulate gene expression by diverse mechanisms, which are still emerging and incompletely understood. We focused on multiple flow-sensitive miRNAs such as, miR-10a, -19a, -23b, -17~92, -21, -663, -92a, -143/145, -101, -126, -712, -205, and -155 that play a critical role in endothelial function and atherosclerosis by targeting inflammation, cell cycle, proliferation, migration, apoptosis, and nitric oxide signaling. Flow-dependent regulation of lncRNAs is just emerging, and their role in vascular dysfunction and atherosclerosis is unknown. Here, we discuss the flow-sensitive lncRNA STEEL along with other lncRNAs studied in the context of vascular pathophysiology and atherosclerosis such as MALAT1, MIAT1, ANRIL, MYOSLID, MEG3, SENCR, SMILR, LISPR1, and H19. Also discussed is the use of these noncoding RNAs as potential biomarkers and therapeutics to reduce and regress atherosclerosis.

Targeting Long Noncoding RNA in Glioma: A Pathway Perspective

Long noncoding RNAs (lncRNAs) participate extensively in biological processes of various cancers. The majority of these transcripts are uniquely expressed in differentiated tissues or specific cancer types. lncRNAs are aberrantly expressed in gliomas and exert diverse functions. In this article, we provided an overview of how lncRNAs regulate cellular processes in glioma, enumerated the lncRNAs that may act as glioma biomarkers, and showed their potential clinical implications.

Exploring Long Noncoding RNAs in Glioblastoma: Regulatory Mechanisms and Clinical Potentials

Gliomas are primary brain tumors presumably derived from glial cells. The WHO grade IV glioblastoma (GBM), characterized by rapid cell proliferation, easily recrudescent, high morbidity, and mortality, is the most common, devastating, and lethal gliomas. Molecular mechanisms underlying the pathogenesis and progression of GBMs with potential diagnostic and therapeutic value have been explored industriously. With the advent of high-throughput technologies, numerous long noncoding RNAs (lncRNAs) aberrantly expressed in GBMs were discovered recently, some of them probably involved in GBM initiation, malignant progression, relapse and resistant to therapy, or showing diagnostic and prognostic value. In this review, we summarized the profile of lncRNAs that has been extensively investigated in glioma research, with a focus on their regulatory mechanisms. Then, their diagnostic, prognostic, and therapeutic implications were also discussed.

Long non-coding RNA UBE2CP3 enhances HCC cell secretion of VEGFA and promotes angiogenesis by activating ERK1/2/HIF-1α/VEGFA signalling in hepatocellular carcinoma

Background

Angiogenesis is considered as an important process in the development of malignancies and is associated with cancer progression and metastasis. Hepatocellular carcinoma (HCC) is the most common primary tumor of the liver and is recognized as a typical angiogenic tumor. Thus, it is of great importance to study the underlying mechanism of angiogenesis in HCC. The long non-coding RNA (lncRNA) ubiquitin conjugating enzyme E2C pseudogene 3 (UBE2CP3) has been reported as an oncogene that promotes tumor metastasis in HCC. However, the role and underlying mechanisms of UBE2CP3 in HCC angiogenesis are still unclear.

Methods

We measured the expression levels of UBE2CP3 by in situ hybridization (ISH) and quantitative real-time polymerase chain reaction (qRT-PCR) in HCC patient samples. We also concomitantly used CD31/PAS double-staining to measure endothelial vessel (EV) density and used qRT-PCR to measure the CD31 mRNA level. HepG2 and SMMC-7721 cells were transfected with Lv-UBE2CP3 or Sh-UBE2CP3 virus to obtain stably over-expressing or knocking-down UBE2CP3 cell lines. The indirect effects of UBE2CP3 on ECs were studied by establishing a co-culture system using Transwell chambers with a 0.4-μm pore size. HCC cells and ECs in the co-culture system were separated, but the cytokines and growth factors were able to communicate with each other. Following exposed to HCC cells, ECs were collected for functional studies. Finally, we studied the function of UBE2CP3 in vivo by chick embryo chorioallantoic membrane (CAM) angiogenesis assays and nude mouse tumorigenicity assays.

Results

In this study, we found that UBE2CP3 expression was higher in HCC tissues than in para-tumor tissues and was up-regulated in tissues with high EV density. Functionally, we found that in the co-culture systems, HCC cells overexpressing UBE2CP3 promoted HUVEC proliferation, migration and tube formation via the activation of ERK/HIF-1α/p70S6K/VEGFA signalling, increasing the level of VEGFA in HCC cell supernatant. In addition, the opposite results appeared when the expression of UBE2CP3 in HCC cells was knocked down. Consistent with these results, CAM angiogenesis assays and nude mouse tumorigenicity assays showed that UBE2CP3 expression up-regulated EV density in vivo.

Conclusion

Our study suggests that UBE2CP3 can enhance the interaction between HCC tumor cells and HUVECs and promote HCC tumorigenicity by facilitating angiogenesis.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0727-1) contains supplementary material, which is available to authorized users.