Knockdown of long non-coding RNA XIST increases blood-tumor barrier permeability and inhibits glioma angiogenesis by targeting miR-137

Overexpressed microRNA-103a-3p inhibits acute lower-extremity deep venous thrombosis via inhibition of CXCL12

Studies have shown that microRNAs (miRNAs) participate in almost all pathological and physiological processes including acute lower-extremity deep venous thrombosis (LEDVT). Here, this study was designed to elucidate the possible function of miR-103a-3p in acute LEDVT. Expression of miR-103a-3p and chemokine C-X-C motif ligand 12 (CXCL12) was initially quantified in plasma collected from 81 LEDVT patients. Then LEDVT mouse models were established by injection with 3% sodium pentobarbital. The interaction between miR-103a-3p and CXCL12 was identified by dual-luciferase reporter gene assay. After gain- and loss-of-function studies, interleukin-6 (IL-6) and IL-8 and tissue factor (TF) levels, and expression of plasminogen activator inhibitors (PAIs), von Willebrand factor (vWF), thromboxane A2 (TH-A2), F4/80, IL-12, Arginase-1 (Arg-1) and CD206 were determined using enzyme-linked immunosorbent assay (ELISA), reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot analysis, respectively. miR-103a-3p was downregulated, while CXCL12 was upregulated in patients and mice with LEDVT. miR-103a-3p targets CXCL12 and inhibited its expression. Overexpressed miR-103a-3p or downregulated CXCL12 decreased expression of IL-6, IL-8, TF, PAIs, vWF, TH-A2, M1 markers (IL-6 and IL-12), yet increased expression of M2 markers (Arg-1 and CD206) in LEDVT mice. Additionally, upregulated miR-103a-3p or silencing CXCL12 suppressed thrombosis in LEDVT mice. However, overexpression of CXCL12 reversed the tendency mentioned above. Altogether, miR-103a-3p can potentially downregulate CXCL12 expression to disrupt inflammatory response and thrombosis, ultimately preventing the development of LEDVT. Our findings underscore a possible alternative therapeutic strategy to limit LEDVT.

Long Non-Coding RNA (lncRNA) X-Inactive Specific Transcript (XIST) Plays a Critical Role in Predicting Clinical Prognosis and Progression of Colorectal Cancer

Background

Long non-coding RNAs (lncRNAs) participate in all cancer biology processes of cells. Although functions and associated mechanisms of lncRNAs have been proven in colorectal cancer (CRC), the roles of lncRNA X-inactive specific transcript (XIST) have not been clearly investigated in CRC.

Material/Methods

Expression of XIST was detected by quantitative real-time PCR (qRT-PCR) assay in CRC cell lines and 196 clinical samples. Correlations between XIST expression and CRC clinicopathological features were analyzed. Log-rank test and Kaplan-Meier test were performed to assess and compare the prognoses of patients with higher and lower expression of XIST. The multivariate Cox regression and univariate Cox regression were conducted to evaluate the risk factors for prognosis of CRC.

Results

lncRNA XIST was upregulated in CRC cells lines and tissues (p<0.05). Statistical analysis found high XIST expression was correlated with larger tumor size, N1, M1, and topography lymph node metastasis (TNM) III+IV stage of CRC. Moreover, higher expression of XIST could predict poor progression-free survival (PFS) and poor overall survival (OS) of CRC patients. The M1 stage and high expression of XIST were proven to be independent risk factors for poor prognosis (p<0.05).

Conclusions

XIST is upregulated in CRC and is significantly correlated with CRC clinical progression. lncRNA XIST overexpression predict poor PFS and poor OS for CRC patients. lncRNA XIST can be an independent risk factor for CRC prognosis, and could be a potential therapeutic target and prognostic biomarker for CRC patients.

Long noncoding RNAs, emerging and versatile regulators of tumor-induced angiogenesis

Angiogenesis is an essential step in maintaining tumor growth and facilitating metastasis. The regulatory mechanisms of tumor-induced angiogenesis are extremely complicated, and include sophisticated crosstalk between tumors and surrounding microenvironment cells, oncogenic signaling pathway activation and aberrant expression of angiogenesis-related genes. Recently, emerging evidence demonstrated that long noncoding RNAs (lncRNAs) play crucial roles in angiogenesis. However, there are lack of reports to review the progression in this scientific field. Here, we focus on and summarize the latest findings of lncRNA in angiogenesis in various cancers. Firstly, we introduced how lncRNAs in tumor cells to modulate the cellular signaling axis, interact with proteins and serve as competitive endogenous RNAs (ceRNAs) to alter target gene expression, by which induce endothelial cell to form capillaries. Then, we recapitulated the essential functions of lncRNA in endothelial cells, and how lncRNAs in tumor-associated macrophages to mediate angiogenesis. Next, the angiogenesis mechanism of tumor-derived lncRNAs via exosomes were collectively described. At last, the effects of lncRNAs on vasculogenic mimicry were summarized, which showed that malignant tumor cells acquire dedifferentiated and endothelial properties to form vessel-like structures by themselves. This review provides new insights into the complexity of angiogenesis, and suggests that lncRNAs may become promising biomarkers and targets for enhancing the efficacy of anti-angiogenesis therapy in cancer.

Knockdown of linc01023 restrains glioma proliferation, migration and invasion by regulating IGF-1R/AKT pathway

LncRNAs have been proved to be involved in the promotion of glioma cell malignant development. However, the exact roles and molecular mechanisms of linc01023 in glioma remain blurred. In this study, we confirm linc01023 is up-regulated in glioma tissues and cell lines. In addition, elevated linc01023 expression indicates shorter survival times in patients with glioma. Moreover, loss-of-function studies reveal that restoration of linc01023 restrains glioma cell proliferation, migration and invasion by regulating IGF1R/AKT pathway in vitro and in vivo. Collectively, the study indicates that linc01023 plays an oncogenic role in glioma through activation of IGF1R/AKT signal pathway, and it could be a candidate therapeutic target.

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.

Chimeric NANOG repressors inhibit glioblastoma growth in vivo in a context-dependent manner

Targeting stemness promises new therapeutic strategies against highly invasive tumors. While a number of approaches are being tested, inhibiting the core transcription regulatory network of cancer stem cells is an attractive yet challenging possibility. Here we have aimed to provide the proof of principle for a strategy, previously used in developmental studies, to directly repress the targets of a salient stemness and pluripotency factor: NANOG. In doing so we expected to inhibit the expression of so far unknown mediators of pro-tumorigenic NANOG function. We chose NANOG since previous work showed the essential requirement for NANOG activity for human glioblastoma (GBM) growth in orthotopic xenografts, and it is apparently absent from many adult human tissues thus likely minimizing unwanted effects on normal cells. NANOG repressor chimeras, which we name NANEPs, bear the DNA-binding specificity of NANOG through its homeodomain (HD), and this is linked to transposable human repressor domains. We show that in vitro and in vivo, NANEP5, our most active NANEP with a HES1 repressor domain, mimics knock-down (kd) of NANOG function in GBM cells. Competition orthotopic xenografts also reveal the effectiveness of NANEP5 in a brain tumor context, as well as the specificity of NANEP activity through the abrogation of its function via the introduction of specific mutations in the HD. The transcriptomes of cells expressing NANEP5 reveal multiple potential mediators of pro-tumorigenic NANEP/NANOG action including intercellular signaling components. The present results encourage further studies on the regulation of context-dependent NANEP abundance and function, and the development of NANEP-based anti-cancer therapies.

Liquid Biopsies in Lung Cancer: Four Emerging Technologies and Potential Clinical Applications

Background: Liquid biopsies offer a promising alternative to tissue samples, providing non-invasive diagnostic approaches or serial monitoring of disease evolution. However, certain challenges remain, and the full potential of liquid biopsies has yet to be reached. Here we report several methodological approaches to interrogate liquid biopsies using circulating tumour cell (CTC) enumeration and characterisation, transcriptomics, Raman spectroscopy, and copy number instability (CNI) scores using blood samples of lung cancer (LC) patients. Methods: We choose LC; since it still is the most common cause of cancer-related mortality worldwide, and therefore there is a need for development of new non-invasive diagnostic/prognostic technologies. Changes in gene expression were assessed using RNA-seq, and in CTCs using ImageStream, an imaging flow-cytometer. CNI scores, from paired tissue/ctDNA were also explored. Raman spectroscopy was used to provide chemical fingerprints of plasma samples. Results: CTCs were detected in all LC patients (n = 10). We observed a significant increase in CTC levels in LC patients (n = 10) compared to controls (n = 21). A similar CNI was noted in the tissue and plasma of 2 patients, where higher CNI scores corresponded with poorer outcome. Significant changes in Raman spectra (carotenoid concentrations) were noted in LC patients (n = 20) compared to controls (n = 10). RNA-seq revealed differential expression of 21 genes between LC cases and controls in both LC tissue and blood samples. Conclusions: Liquid biopsies can potentially provide a more comprehensive picture of the disease compared to a single tissue biopsy. CTC enumeration is feasible and sensitive for LC patients. Molecular profiling of CTCs is also possible from total blood. CNI scores and Raman spectra require further investigation. Further work is being undertaken to explore these methods of detection in a larger LC cohort.

The role of LINC00094/miR-224-5p (miR-497-5p)/Endophilin-1 axis in Memantine mediated protective effects on blood-brain barrier in AD microenvironment

The dysfunction of the blood-brain barrier (BBB) is one of the main pathological features of Alzheimer's disease (AD). Memantine (MEM), an N-methyl-d-aspartate (NMDA) receptor antagonist, has been reported that been used widely for AD therapy. This study was performed to demonstrate the role of the MEM in regulating BBB permeability in AD microenvironment as well as its possible mechanisms. The present study showed that LINC00094 was dramatically increased in Abeta_1-42 -incubated microvascular endothelial cells (ECs) of BBB model in vitro. Besides, it was decreased in MEM-incubated ECs. Silencing LINC00094 significantly decreased BBB permeability, meanwhile up-regulating the expression of ZO-1, occludin and claudin-5. Furthermore, silencing LINC00094 enhance the effect of MEM on decreasing BBB permeability in AD microenvironment. The analysis of the mechanism demonstrated that reduction of LINC00094 inhibited Endophilin-1 expression by up-regulating miR-224-4p/miR-497-5p, promoted the expression of ZO-1, occludin and claudin-5, and ultimately alleviated BBB permeability in AD microenvironment. Taken together, the present study suggests that the MEM/LINC00094/miR-224-5p (miR-497-5p)/Endophilin-1 axis plays a crucial role in the regulation of BBB permeability in AD microenvironment. Silencing LINC00094 combined with MEM provides a novel target for the therapy of AD.

Testing of library preparation methods for transcriptome sequencing of real life glioblastoma and brain tissue specimens: A comparative study with special focus on long non-coding RNAs

Current progress in the field of next-generation transcriptome sequencing have contributed significantly to the study of various malignancies including glioblastoma multiforme (GBM). Differential sequencing of transcriptomes of patients and non-tumor controls has a potential to reveal novel transcripts with significant role in GBM. One such candidate group of molecules are long non-coding RNAs (lncRNAs) which have been proved to be involved in processes such as carcinogenesis, epigenetic modifications and resistance to various therapeutic approaches. To maximize the value of transcriptome sequencing, a proper protocol for library preparation from tissue-derived RNA needs to be found which would produce high quality transcriptome sequencing data and increase the number of detected lncRNAs. It is important to mention that success of library preparation is determined by the quality of input RNA, which is in case of real-life tissue specimens very often altered in comparison to high quality RNA commonly used by manufacturers for development of library preparation chemistry. In the present study, we used GBM and non-tumor brain tissue specimens and compared three different commercial library preparation kits, namely NEXTflex Rapid Directional qRNA-Seq Kit (Bioo Scientific), SENSE Total RNA-Seq Library Prep Kit (Lexogen) and NEBNext Ultra II Directional RNA Library Prep Kit for Illumina (NEB). Libraries generated using SENSE kit were characterized by the most normal distribution of normalized average GC content, the least amount of over-represented sequences and the percentage of ribosomal RNA reads (0.3–1.5%) and highest numbers of uniquely mapped reads and reads aligning to coding regions. However, NEBNext kit performed better having relatively low duplication rates, even transcript coverage and the highest number of hits in Ensembl database for every biotype of our interest including lncRNAs. Our results indicate that out of three approaches the NEBNext library preparation kit was most suitable for the study of lncRNAs via transcriptome sequencing. This was further confirmed by highly consistent data reached in an independent validation on an expanded cohort.

The Role of ACKR3 in Breast, Lung, and Brain Cancer

Recent reports regarding the significance of chemokine receptors in disease have put a spotlight on atypical chemokine receptor 3 (ACKR3). This atypical chemokine receptor is overexpressed in numerous cancer types and has been involved in the modulation of tumor cell proliferation and migration, tumor angiogenesis, or resistance to drugs, thus contributing to cancer progression and metastasis occurrence. Here, we focus on the clinical significance and potential mechanisms underlying the pathologic role of ACKR3 in breast, lung, and brain cancer and discuss its possible relevance as a prognostic factor and potential therapeutic target in these contexts.

LncRNA X inactive specific transcript contributes to neuropathic pain development by sponging miR-154-5p via inducing toll-like receptor 5 in CCI rat models

Noncoding RNAs, including long non-coding RNAs (lncRNAs) and microRNAs, are involved in the development of neuropathic pain. Currently, we investigated that lncRNA X inactive-specific transcript (XIST) and toll-like receptor 5 (TLR5) were greatly upregulated in chronic constriction injury rat models, whereas miR-154-5p (microRNA-154-5p) was significantly downregulated. Bioinformatics analysis was used to predict miR-154-5p as a target gene of XIST, and dual-luciferase reporter tests proved the correlation between them. We observed that miR-154-5p was negatively modulated by XIST in vitro. XIST overexpression markedly induced neuropathic pain development in rats with chronic constriction injury, whereas the upregulation of miR-154-5p could reverse this phenomenon. Furthermore, TLR5 was demonstrated to be a target gene of miR-154-5p by using bioinformatics predictions. miR-154-5p negatively regulated TLR5 expression in vitro, and TLR5 was able to promote neuropathic pain development. In addition, overexpressing miR-154-5p can reverse the role of TLR5 neuropathic pain in vivo. Taken these together, we indicated that XIST could increase TLR5 expression by acting as a sponge of miR-154-5p in neuropathic pain development. This study revealed that XIST can contribute to neuropathic pain progression in rats through decreasing miR-154-5p and increasing TLR5. The XIST/miR-154-5p/ TLR5 axis can be provided as a novel therapeutic target in treating neuropathic pain.

A dynamic and integrated epigenetic program at distal regions orchestrates transcriptional responses to VEGFA

Cell behaviors are dictated by epigenetic and transcriptional programs. Little is known about how extracellular stimuli modulate these programs to reshape gene expression and control cell behavioral responses. Here, we interrogated the epigenetic and transcriptional response of endothelial cells to VEGFA treatment and found rapid chromatin changes that mediate broad transcriptomic alterations. VEGFA-responsive genes were associated with active promoters, but changes in promoter histone marks were not tightly linked to gene expression changes. VEGFA altered transcription factor occupancy and the distal epigenetic landscape, which profoundly contributed to VEGFA-dependent changes in gene expression. Integration of gene expression, dynamic enhancer, and transcription factor occupancy changes induced by VEGFA yielded a VEGFA-regulated transcriptional regulatory network, which revealed that the small MAF transcription factors are master regulators of the VEGFA transcriptional program and angiogenesis. Collectively these results revealed that extracellular stimuli rapidly reconfigure the chromatin landscape to coordinately regulate biological responses.

Long Noncoding RNA XIST Regulates miR-137-EZH2 Axis to Promote Tumor Metastasis in Colorectal Cancer

We aimed to investigate the significant role of long noncoding RNA X inactive specific transcript (XIST) in regulating tumor metastasis in colorectal cancer (CRC), as well as its possible mechanism. Expression of lncRNA XIST in CRC tissues and CRC cells was detected. CRC cells were transfected with pc-XIST, blank control si-XIST, or si-control, and then the effects of lncRNA XIST on CRC cell migration and invasion were investigated, along with the interaction between lncRNA XIST and miR-137. lncRNA XIST was upregulated in CRC tissues. Compared with HT29 cells that had low metastatic potential, XIST was markedly more highly expressed in LoVo cells that had a higher metastatic potential. Overexpression of XIST promoted the migratory and invasive potential of HT29 cells, while knockdown of XIST inhibited the migratory and invasive potential of LoVo cells. Moreover, epithelial-mesenchymal transition (EMT) markers, including E-cadherin, N-cadherin, and vimentin, exhibited corresponding expression changes. In addition, miR-137 was inhibited by XIST, and inhibition of miR-137 could reverse the effects of knockdown of XIST on the migratory and invasive potential of LoVo cells. Furthermore, enhancer of zeste homolog 2 (EZH2) was confirmed as a target of miR-137. Our data reveal that lncRNA XIST may promote tumor metastasis in CRC possibly through regulating the miR-137-EZH2 axis. lncRNA XIST may serve as a prognostic indicator for CRC progression.

Non-Coding RNAs in Glioma

Glioma is the most aggressive brain tumor of the central nervous system. The ability of glioma cells to migrate, rapidly diffuse and invade normal adjacent tissue, their sustained proliferation, and heterogeneity contribute to an overall survival of approximately 15 months for most patients with high grade glioma. Numerous studies indicate that non-coding RNA species have critical functions across biological processes that regulate glioma initiation and progression. Recently, new data emerged, which shows that the cross-regulation between long non-coding RNAs and small non-coding RNAs contribute to phenotypic diversity of glioblastoma subclasses. In this paper, we review data of long non-coding RNA expression, which was evaluated in human glioma tissue samples during a five-year period. Thus, this review summarizes the following: (I) the role of non-coding RNAs in glioblastoma pathogenesis, (II) the potential application of non-coding RNA species in glioma-grading, (III) crosstalk between lncRNAs and miRNAs (IV) future perspectives of non-coding RNAs as biomarkers for glioma.

NR2C2-uORF targeting UCA1-miR-627-5p-NR2C2 feedback loop to regulate the malignant behaviors of glioma cells

Accumulating evidence has highlighted the potential role of non-coding RNAs (ncRNAs) and upstream open-reading frames (uORFs) in the biological behaviors of glioblastoma. Here, we elucidated the function and possible molecular mechanisms of the effect of some ncRNAs and NR2C2-uORF on the biological behaviors of gliomas. Quantitative real-time PCR was conducted to profile the cell expression of lnc-UCA1 and microRNA-627-5p (miR-627-5p) in glioma tissues and cells. Western blot assay was used to determine the expression levels of NR2C2, SPOCK1, and NR2C2-uORF in glioma tissues and cells. Stable knockdown of lnc-UCA1 or overexpression of miR-627-5p in glioma cell lines (U87 and U251) were established to explore the function of lnc-UCA1 and miR-627-5p in glioma cells. Further, Dual luciferase report assay was used to investigate the correlation between lnc-UCA1 and miR-627-5p. Cell Counting Kit-8, transwell assays, and flow cytometry were used to investigate lnc-UCA1 and miR-627-5p function including cell proliferation, migration and invasion, and apoptosis, respectively. ChIP assays were used to ascertain the correlations between NR2C2 and SPOCK1 as well as NR2C2 between lnc-UCA1. This study confirmed that lnc-UCA1 was up-regulated in glioma tissues and cells. UCA1 knockdown inhibited the malignancies of glioma cells by reducing proliferation, migration, and invasion, but inducing apoptosis. We found that lnc-UCA1 acted as miR-627-5p sponge in a sequence-specific manner. Meanwhile, upregulated lnc-UCA1 inhibited miR-627-5p expression. In addition, miR-627-5p targeted 3'UTR of NR2C2 and down-regulated its expression. Moreover, UCA1 knockdown impaired NR2C2 expression by upregulating miR-627-5p. An uORF was identified in mRNA 5'UTR of NR2C2 and overexpression of whom negatively regulated NR2C2 expression. Remarkably, lnc-UCA1 knockdown combined with uORF overepression and NR2C2 knockdown led to severe tumor suppression in vivo. This study demonstrated that the NR2C2-uORF impaired the pivotal roles that UCA1-miR-627-5p-NR2C2 feedback loop had in regulating the malignancies of glioma cells by targeting NR2C2 directly. And this may provide a potential therapeutic strategy for treating glioma.

Long non-coding RNAs in hematological malignancies: translating basic techniques into diagnostic and therapeutic strategies

Recent studies have revealed that non-coding regions comprise the vast majority of the human genome and long non-coding RNAs (lncRNAs) are a diverse class of non-coding RNAs that has been implicated in a variety of biological processes. Abnormal expression of lncRNAs has also been linked to different human diseases including cancers, yet the regulatory mechanisms and functional effects of lncRNAs are still ambiguous, and the molecular details also need to be confirmed. Unlike protein-coding gene, it is much more challenging to unravel the roles of lncRNAs owing to their unique and complex features such as functional diversity and low conservation among species, which greatly hamper their experimental characterization. In this review, we summarize and discuss both conventional and advanced approaches for the identification and functional characterization of lncRNAs related to hematological malignancies. In particular, the utility and advancement of clustered regularly interspaced short palindromic repeats (CRISPR)-Cas system as gene-editing tools are envisioned to facilitate the molecular dissection of lncRNAs via different knock-in/out strategies. Besides experimental considerations specific to lncRNAs, the roles of lncRNAs in the pathogenesis and progression of leukemia are also highlighted in the review. We expect that these insights may ultimately lead to clinical applications including development of biomarkers and novel therapeutic approaches targeting lncRNAs.

FOXC1 silencing inhibits the epithelial‑to‑mesenchymal transition of glioma cells: Involvement of β‑catenin signaling

Glioma is a type of malignant brain tumor. Forkhead box C1 (FOXC1) is a conserved transcription factor that is involved in tumorigenesis; however, the function of FOXC1 in glioma remains unclear. The present study aimed to investigate the effects of FOXC1 silencing on the epithelial-to-mesenchymal transition (EMT) of glioma cells. FOXC1-specific small interfering RNAs were employed to downregulate the expression levels of FOXC1 in glioma cells. The proliferation, migration and invasion of glioma cells were assessed by MTT assay, wound healing assay and Transwell assay. Western blot analysis was performed to reveal the effects of FOXC1 on EMT-associated proteins and β-catenin signaling. The results revealed that, following FOXC1 silencing, the proliferation, migration and invasion of glioma cells were decreased. The expression levels of EMT-associated proteins were also affected. Further examination demonstrated that β-catenin signaling was involved in the effects of FOXC1 on glioma cells. Previous results suggested that overexpression of β-catenin reversed the effects of FOXC1 silencing on glioma cells. The present study demonstrated that FOXC1 may regulate the EMT of glioma cells, potentially via β-catenin signaling. Therefore, FOXC1 may be a potential therapeutic target for the treatment of glioma.

Mechanism of piR-DQ590027/MIR17HG regulating the permeability of glioma conditioned normal BBB

Background

The blood-brain barrier (BBB) strongly restricts the entry of anti-glioma drugs into tumor tissues and thus decreases chemotherapy efficacy. Malignant gliomas are highly invasive tumours that use the perivascular space for invasion and co-opt existing vessels as satellite tumor form. Because regulation of the effect of noncoding RNA on BBB function is attracting growing attention, we investigated the effects of noncoding RNA on the permeability of glioma conditioned normal BBB and the mechanism involved using PIWI-associated RNA piR-DQ590027 as a starting point.

Methods

The mRNA levels of MIR17HG, miR-153, miR-377, ZO-1, occludin, and claudin-5 were determined using real-time PCR. Transient cell transfection was performed using Lipofectamine 3000 reagent. TEER and HRP flux were applied to measure the permeability of glioma conditioned normal BBB. Western blotting and immunofluorescence assays were used to measure ZO-1, occludin, and claudin-5 levels. Reporter vector construction and a luciferase reporter assay were performed to detect the binding sites of MIR17HG and piR-DQ590027, MIR17HG and miR-153 (miR-377), and FOXR2 and miR-153 (miR-377). RNA immunoprecipitation was used to test the interaction between miR-153 (miR-377) and its target proteins. Chromatin immunoprecipitation was performed to detect the interaction between the transcription factor FOXR2 and ZO-1, occludin, and claudin-5.

Results

piR-DQ590027 was expressed at low levels in glioma-conditioned ECs (GECs) of the in vitro glioma conditioned normal BBB model. Overexpression of piR-DQ590027 down-regulated the expressions of ZO-1, occludin, and claudin-5 and increased the permeability of glioma conditioned normal BBB. MIR17HG had high expression in GECs but miR-153 and miR-377 had low expression. piR-DQ590027 bound to and negatively regulated MIR17HG. FOXR2 was a downstream target of miR-153 and miR-377; MIR17HG bound separately to miR-153 and miR-377 and negatively regulated their ability to mediate FOXR2 expression. FOXR2 associated with the promoter regions of ZO-1, occludin, and claudin-5 in GECs to promote their transcription.

Conclusion

The piR-DQ590027/MIR17HG/miR-153 (miR-377)/FOXR2 pathway plays an important role in regulating glioma conditioned normal BBB permeability and provides a new target for the comprehensive treatment of glioma.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0886-0) contains supplementary material, which is available to authorized users.

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.

Long Non-Coding RNAs in Gliomas: From Molecular Pathology to Diagnostic Biomarkers and Therapeutic Targets

Gliomas are the most common malignancies of the central nervous system. Because of tumor localization and the biological behavior of tumor cells, gliomas are characterized by very poor prognosis. Despite significant efforts that have gone into glioma research in recent years, the therapeutic efficacy of available treatment options is still limited, and only a few clinically usable diagnostic biomarkers are available. More and more studies suggest non-coding RNAs to be promising diagnostic biomarkers and therapeutic targets in many cancers, including gliomas. One of the largest groups of these molecules is long non-coding RNAs (lncRNAs). LncRNAs show promising potential because of their unique tissue expression patterns and regulatory functions in cancer cells. Understanding the role of lncRNAs in gliomas may lead to discovery of the novel molecular mechanisms behind glioma biological features. It may also enable development of new solutions to overcome the greatest obstacles in therapy of glioma patients. In this review, we summarize the current knowledge about lncRNAs and their involvement in the molecular pathology of gliomas. A conclusion follows that these RNAs show great potential to serve as powerful diagnostic, prognostic, and predictive biomarkers as well as therapeutic targets.

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.

Angio-LncRs: LncRNAs that regulate angiogenesis and vascular disease

Long noncoding RNAs (lncRNAs) represent a large subgroup of RNAs that are longer than 200 nucleotides and have no apparent protein coding potential. They have diverse functions in different biological processes by regulating chromatin remodeling or protein translation. This review summarizes the recent progress of lncRNAs in angiogenesis and vascular diseases. A general overview of lncRNA functional mechanisms will be introduced. A list of lncRNAs, which are termed "Angio-LncRs", including MALAT1, MANTIS, PUNISHER, MEG3, MIAT, SENCR and GATA6-AS, will be discussed regarding their expression, regulation, function and mechanism of action in angiogenesis. Implications of lncRNAs in vascular diseases, such as atherosclerosis, hypertension, vascular retinopathies and tumor angiogenesis will also be discussed.

LncRNA TP73‑AS1 predicts poor prognosis and promotes cell proliferation in ovarian cancer via cell cycle and apoptosis regulation

TP73‑AS1, a critical cancer‑associated long noncoding RNA (lncRNA), has been identified in esophageal cancer and glioma. However, its biological role in ovarian cancer (OC) remains to be investigated. The aim of the present study was to investigate the role of TP73‑AS1 in human OC cell lines and clinical tumor samples to determine the function of this molecule. Reverse transcription‑quantitative polymerase chain reaction analysis was carried out to detect that TP73‑AS1 was upregulated in OC tissues and cell lines. Kaplan Meier Method was applied to study the association between overall survival of patients with OC and TP73‑AS1 expression. The results suggested that patients with high expression levels of TP73‑AS1 had lower survival compared with patients with low expression level of TP73‑AS1. MTT and colony formation assays were conducted to investigate the effects of TP73‑AS1 expression on OC cell proliferation. Flow cytometry analysis was used to analyze the effects of TP73‑AS1 expression on cell cycle progression and apoptosis. Loss‑of‑function experiments revealed that TP73‑AS1 silencing was able to suppress the growth of OC cells via modulating the cell cycle and apoptosis. The results of the present study suggest that TP73‑AS1 may be an oncogenic lncRNA that promotes the proliferation of OC cells and may therefore be an effective therapeutic target in patients with OC.

LncRNA SNHG6 acts as a prognostic factor to regulate cell proliferation in glioma through targeting p21

It has been certified that long noncoding RNAs (lncRNAs) are crucial regulators in the progression of various human cancers. snoRNA host gene 6 (SNHG6) has been uncovered to affect the initial stage and tumorigenesis of hepatocellular carcinoma. Nevertheless, the expression pattern and biological role of SNHG6 in glioma still need to be investigated. The study aims to investigate the expression pattern, biological role and the potential mechanism of SNHG6 in glioma. In this study, the high expression of SNHG6 was tested in both glioma tissues and glioma cells. The correlation between expression levels of SNHG6 and the overall survival of glioma patients was demonstrated by using Kaplan Meier method analysis. Next, gain of function assays revealed that overexpression of SNHG6 can promote the formation of malignant phenotype of 1800 cell. However, results of loss-of-function assays revealed that silenced SNHG6 exerted the inhibitory function on glioma cell growth. Flow cytometric analysis was performed in glioma cells to detect the anti-oncogenic effects of silenced SNHG6 on cell cycle and apoptosis. Finally, we identified that p21 was involved in glioma cell proliferation after SNHG6 was downregulated. Taken together, we concluded that SNHG6 is a regulator and a potential therapeutic target in glioma.

lncRNA FEZF1-AS1 Is Associated With Prognosis in Lung Adenocarcinoma and Promotes Cell Proliferation, Migration, and Invasion

Long noncoding RNAs (lncRNAs) have been reported to play important roles in tumorigenesis. In the present study, we demonstrated that lncRNA forebrain embryonic zinc finger protein 1 (FEZF1) antisense RNA1 (FEZF1-AS1) is markedly upregulated in human lung adenocarcinoma (LAD) tissues and cell lines and is associated with poor prognosis. Loss of function revealed that deletion of FEZF1-AS1 expression significantly inhibited the LAD cell proliferation, invasion, and migration. Further studies revealed that downregulation of FEZF1-AS1 reduced mRNA and protein expression of its sense-cognate gene FEZF1 in LAD cells, and vice versa. Correlation analysis indicated that there was a positive correlation between FEZF1-AS1 and FEZF1 expression in LAD tissues. Additionally, rescue assay confirmed that the function of FEZF1-AS1 in LAD was mediated by FEZF1. Our findings suggested that dysregulation of FEZF1-AS1 contributed to the progression of LAD, which might be a potential target for LAD therapy.

New insights into long noncoding RNAs and their roles in glioma

Glioma is one of the most prevalent types of primary intracranial carcinoma with varying malignancy grades I–IV and histological subtypes, including astrocytomas, glioblastoma multiform (GBM), oligodendrogliomas and mixed tumors. Glioma is characterized by rapid cell proliferation and angiogenesis, and the WHO grade IV glioblastoma, which is highly malignant with poor prognosis because GBM stem-like cells (GSCs) are resistant to conventional therapy and easily recrudescent, accounts for the majority of gliomas. Consequently, investigations exploring the accurate molecular mechanisms and reliable therapeutic targets for gliomas have drawn extensive attention.

Based on the increasing amount of functional lncRNAs aberrantly expressed in glioma tissues and cell lines, lncRNAs might be critical for glioma initiation, progression and other malignant phenotypes. This review summarizes the latest insights into the lncRNA field and their functional roles in glioma, therefore evaluating the potential clinical applications of lncRNAs as prospective novel biomarkers and therapeutic targets.

The long non-coding RNA SNHG14 inhibits cell proliferation and invasion and promotes apoptosis by sponging miR-92a-3p in glioma

Malignant glioma is one of the most common types of primary brain tumours. Long non-coding RNAs (lncRNAs) have recently emerged as a new class of therapeutic targets for many cancers. In this study, we aimed to explore the functional involvement of small nucleolar RNA host gene 14 (SNHG14) and its potential regulatory mechanism in glioma progression. SNHG14 was found to be downregulated in human glioma tissues and cell lines. SNHG14 significantly inhibited cell viability, reduced cell invasion, and induced apoptosis in glioma cell lines. Furthermore, a correlation analysis demonstrated that there was a negative correlation between SNHG14 expression and miR-92a-3p expression. Bioinformatics prediction and luciferase reporter assays demonstrated that miR-92a-3p could directly bind to SNHG14. miR-92a-3p was significantly upregulated in glioma and acted as an oncogene in glioma cells by inhibiting Bim. Moreover, mechanistic investigations showed that miR-92a-3p could reverse the tumour suppressive effects induced by SNHG14 in glioma, indicating that SNHG14 may act as an endogenous sponge that competes for binding to miR-92a-3p. Our results suggest that SNHG14 and miR-92a-3p may be promising molecular targets for glioma therapy.

PIWIL1/piRNA-DQ593109 Regulates the Permeability of the Blood-Tumor Barrier via the MEG3/miR-330-5p/RUNX3 Axis

The blood-tumor barrier (BTB) restricts the efficient delivery of anti-glioma drugs to cranial glioma tissues. Increased BTB permeability may allow greater delivery of the therapeutic agents. Increasing evidence has revealed that PIWI proteins and PIWI-interacting RNAs (piRNAs) play an important role in tumor progression. However, whether PIWI proteins and piRNAs regulate BTB permeability remains unclear. In the present study, we demonstrated that the PIWIL1/piRNA-DQ593109 (piR-DQ593109) complex was the predominant regulator of BTB permeability. Briefly, PIWIL1 was upregulated in glioma endothelial cells (GECs). Furthermore, piR-DQ593109 was also overexpressed in GECs, as revealed via a piRNA microarray. Downregulation of PIWIL1 or piR-DQ593109 increased the permeability of the BTB. Moreover, PIWIL1 and piR-DQ593109, which formed a piRNA-induced silencing complex, degraded the long non-coding RNA maternally expressed 3 (MEG3) in a sequenced-dependent manner. Furthermore, restoring MEG3 released post-transcriptional inhibition of Runt related transcription factor 3 (RUNX3) by sponging miR-330-5p. In addition, RUNX3 bounded to the promoter regions and reduced the promoter activities of ZO-1, occludin, and claudin-5, which significantly impaired the expression levels of ZO-1, occludin, and claudin-5. In conclusion, downregulating PIWIL1 and piR-DQ593109 increased BTB permeability through the MEG3/miR-330-5p/RUNX3 axis. These data may provide insight into glioma treatment.

Molecular Determinants of Malignant Brain Cancers: From Intracellular Alterations to Invasion Mediated by Extracellular Vesicles

Malignant glioma cells invade the surrounding brain parenchyma, by migrating along the blood vessels, thus promoting cancer growth. The biological bases of these activities are grounded in profound alterations of the metabolism and the structural organization of the cells, which consequently acquire the ability to modify the surrounding microenvironment, by altering the extracellular matrix and affecting the properties of the other cells present in the brain, such as normal glial-, endothelial- and immune-cells. Most of the effects on the surrounding environment are probably exerted through the release of a variety of extracellular vesicles (EVs), which contain many different classes of molecules, from genetic material to defined species of lipids and enzymes. EV-associated molecules can be either released into the extracellular matrix (ECM) and/or transferred to neighboring cells: as a consequence, both deep modifications of the recipient cell phenotype and digestion of ECM components are obtained, thus causing cancer propagation, as well as a general brain dysfunction. In this review, we first analyze the main intracellular and extracellular transformations required for glioma cell invasion into the brain parenchyma; then we discuss how these events may be attributed, at least in part, to EVs that, like the pawns of a dramatic chess game with cancer, open the way to the tumor cells themselves.

lncRNA FAM83H-AS1 is associated with the prognosis of colorectal carcinoma and promotes cell proliferation by targeting the Notch signaling pathway

The long non-coding RNA, FAM83H antisense RNA 1 (head to head) (FAM83H-AS1), has exhibited a functional role as an oncogene in a number of different types of cancer. The aim of the present study was to reveal the dysregulation of FAM83H-AS1 in colorectal carcinoma (CRC) samples and elucidate its underlying associations with the Notch signaling pathway. The expression profiles of FAM83H-AS1 and two Notch signaling-associated molecules, Notch1 and Hes family basic-helix-loop-helix transcription factor 1 (Hes1), were measured by reverse transcription-polymerase chain reaction and western blot analysis. The Pearson χ² test was employed to evaluate the associations between FAM83H-AS1 expression and clinical features. A statistically significant positive association between the expression levels of FAM83H-AS1 and those of Notch1 or Hes1 in CRC tissues was analyzed by Spearman's correlation analysis. The Kaplan-Meier method was used to compare the overall survival curves between the highly-expressed and low-expressed FAM83H-AS1 groups via a log-rank test. Specific small hairpin RNA was transfected to silence endogenous FAM83H-AS1. MTT and colony formation assays were performed to measure the growth-inhibition effect of silenced FAM83H-AS1. The levels of FAM83H-AS1, Notch1 and Hes1 were significantly increased in CRC samples and cell lines. Cell proliferation was markedly inhibited when FAM83H-AS1 was knocked down and this effect mediated by FAM83H-AS1 could be reversed by Notch1 regulators. Thus, downregulated FAM83H-AS1 exhibited an anti-proliferative role in CRC by repressing the Notch signaling pathway.

lncRNA SNHG5 is associated with poor prognosis of bladder cancer and promotes bladder cancer cell proliferation through targeting p27

Long non-coding RNAs (lncRNAs) have been identified as critical regulators in tumorigenesis. In our present study, we measured the level of small nucleolar RNA host gene 5 (SNHG5) in bladder cancer (BC) tissues and cell lines, and the correlation of the level of SNHG5 with clinicopathological features and prognosis of BC patients was analyzed. Reverse transcription-quantitative polymerase chain reaction was performed to determine the level of SNHG5 in the BC tissues and cell lines. The Kaplan-Meier method was used to analyze the long-term survival outcomes. MTT and colony formation assays were applied to assess the influence of SNHG5 on cell proliferation ability. Flow cytometry was used to measure the function of SNHG5 on cell cycle and apoptosis rate. SNGH5 was found upregulated in BC tissues and cell lines and a high level of SNGH5 was correlated with a poor prognosis. Silencing SNHG5 inhibited the proliferation ability of BC cells and such a function was attributed to its influence on cells cycle and apoptosis. Our findings imply that SNHG5 was upregulated in BC tissues and played an important role in BC progression and may be a potential therapeutic target for BC patients.

SNHG16/miR-216-5p/ZEB1 signal pathway contributes to the tumorigenesis of cervical cancer cells

Long non-coding RNAs (lncRNAs) have been confirmed as crucial regulators in tumorgenesis. Small nucleolar RNA host gene 16 (SNHG16) has been recently uncovered to be a potential oncogene in several types of cancers. However, its expression level and potential role in cervical cancer remain uncertain. In our research, we assessed the expression level of SNHG16 in clinical cervical cancer tissues and cells. We made use of functional assays to determine the biological effects of SNHG16 on cell proliferation and migration of cervical cancer. By employing the bioinformatics analysis tools, we revealed that miR-216-5p could interact with SNHG16 and there existed a negative correlation between the expression levels of miR-216-5p and SNHG16 in cervical cancer specimens. Furthermore, RIP assay, RNA pulldown system and dual luciferase reporter assays confirmed that SNHG16 directly targeted miR-216-5p by harboring the binding sites of microRNA in the SNHG16 sequence. Additionally, bioinformatics analysis provided an evidence that ZEB1 was a potential target of miR-216-5p. Collectively, it was suggested that SNHG16 could serve as an oncogene that promoted tumor progression by acting as an endogenous 'sponge' to regulate miR-216A-5p/ZEB1.

LincRNA FEZF1-AS1 contributes to the proliferation of LAD cells by silencing p57 expression

LincRNA FEZF1-AS1 has been identified to exert oncogenic functions in various biological processes of tumorigenesis. However, the function of FEZF1-AS1 in lung adenocarcinoma still remains unclear. Our findings revealed that FEZF1-AS1 was increased in lung adenocarcinoma tissues and cell lines and high level of FEZF1-AS1 was associated with poor prognosis of lung adenocarcinoma. Functional experiments and mechanistic investigations demonstrated that knockdown of FEZF1-AS1 significantly repressed proliferation through influencing the distribution of cell cycle. Besides, we also uncovered that FEZF1-AS1 could suppress p57 expression through recruiting EZH2 and LSD1 to the promoter of p57, thus influenced the cell cycle and proliferation. Collectively, our results suggested that FEZF1-AS1 was involved in the progression of lung adenocarcinoma and might be as a potential therapy target for human lung adenocarcinoma.

Transcription Factor NFAT5 Promotes Glioblastoma Cell-driven Angiogenesis via SBF2-AS1/miR-338-3p-Mediated EGFL7 Expression Change

Glioblastoma (GBM) is the most aggressive primary intracranial tumor of adults and confers a poor prognosis due to high vascularization. Hence anti-angiogenic therapy has become a promising strategy for GBM treatment. In this study, the transcription factor nuclear factor of activated T-cells 5 (NFAT5) was significantly elevated in glioma samples and GBM cell lines, and positively correlated with glioma WHO grades. Knockdown of NFAT5 inhibited GBM cell-driven angiogenesis. Furthermore, long non-coding RNA SBF2 antisense RNA 1 (SBF2-AS1) was upregulated in glioma samples and knockdown of SBF2-AS1 impaired GBM-induced angiogenesis. Downregulation of NFAT5 decreased SBF2-AS1 expression at transcriptional level. In addition, knockdown of SBF2-AS1 repressed GBM cell-driven angiogenesis via enhancing the inhibitory effect of miR-338-3p on EGF like domain multiple 7 (EGFL7). In vivo study demonstrated that the combination of NFAT5 knockdown and SBF2-AS1 knockdown produced the smallest xenograft volume and the lowest microvessel density. NFAT5/SBF2-AS1/miR-338-3p/EGFL7 pathway may provide novel targets for glioma anti-angiogenic treatment.

Non-coding RNAs in the Ovarian Follicle

The mammalian ovarian follicle is the complex reproductive unit comprising germ cell, somatic cells (Cumulus and Granulosa cells), and follicular fluid (FF): paracrine communication among the different cell types through FF ensures the development of a mature oocyte ready for fertilization. This paper is focused on non-coding RNAs in ovarian follicles and their predicted role in the pathways involved in oocyte growth and maturation. We determined the expression profiles of microRNAs in human oocytes and FF by high-throughput analysis and identified 267 microRNAs in FF and 176 in oocytes. Most of these were FF microRNAs, while 9 were oocyte specific. By bioinformatic analysis, independently performed on FF and oocyte microRNAs, we identified the most significant Biological Processes and the pathways regulated by their validated targets. We found many pathways shared between the two compartments and some specific for oocyte microRNAs. Moreover, we found 41 long non-coding RNAs able to interact with oocyte microRNAs and potentially involved in the regulation of folliculogenesis. These data are important in basic reproductive research and could also be useful for clinical applications. In fact, the characterization of non-coding RNAs in ovarian follicles could improve reproductive disease diagnosis, provide biomarkers of oocyte quality in Assisted Reproductive Treatment, and allow the development of therapies for infertility disorders.