Long noncoding RNA FTX is upregulated in gliomas and promotes proliferation and invasion of glioma cells by negatively regulating miR-342-3p

Patient- and xenograft-derived organoids recapitulate pediatric brain tumor features and patient treatments

Brain tumors are the leading cause of cancer-related death in children. Experimental in vitro models that faithfully capture the hallmarks and tumor heterogeneity of pediatric brain cancers are limited and hard to establish. We present a protocol that enables efficient generation, expansion, and biobanking of pediatric brain cancer organoids. Utilizing our protocol, we have established patient-derived organoids (PDOs) from ependymomas, medulloblastomas, low-grade glial tumors, and patient-derived xenograft organoids (PDXOs) from medulloblastoma xenografts. PDOs and PDXOs recapitulate histological features, DNA methylation profiles, and intratumor heterogeneity of the tumors from which they were derived. We also showed that PDOs can be xenografted. Most interestingly, when subjected to the same routinely applied therapeutic regimens, PDOs respond similarly to the patients. Taken together, our study highlights the potential of PDOs and PDXOs for research and translational applications for personalized medicine.

Emerging roles of long non-coding RNA FTX in human disorders

Long non-coding RNAs (lncRNAs) are involved the progression of cancerous and non-cancerous disorders via different mechanism. FTX (five prime to xist) is an evolutionarily conserved lncRNA that is located upstream of XIST and regulates its expression. FTX participates in progression of various malignancy including gastric cancer, glioma, ovarian cancer, pancreatic cancer, and retinoblastoma. Also, FTX can be involved in the pathogenesis of non-cancerous disorders such as endometriosis and stroke. FTX acts as competitive endogenous RNA (ceRNA) and via sponging various miRNAs, including miR-186, miR-200a-3p, miR-215-3p, and miR-153-3p to regulate the expression of their downstream target. FTX by targeting various signaling pathways including Wnt/β-catenin, PI3K/Akt, SOX4, PDK1/PKB/GSK-3β, TGF-β1, FOXA2, and PPARγ regulate molecular mechanism involved in various disorders. Dysregulation of FTX is associated with an increased risk of various disorders. Therefore, FTX and its downstream targets may be suitable biomarkers for the diagnosis and treatment of human malignancies. In this review, we summarized the emerging roles of FTX in human cancerous and non-cancerous cells.

The Involvement of Long Non-Coding RNAs in Glioma: From Early Detection to Immunotherapy

Glioma is a brain tumor that arises in the central nervous system and is categorized according to histology and molecular genetic characteristics. Long non-coding RNAs (lncRNAs) are RNAs longer than 200 nucleotides in length. They have been reported to influence significant events such as carcinogenesis, progression, and increased treatment resistance on glioma cells. Long non-coding RNAs promote cell proliferation, migration, epithelial-to-mesenchymal transition and invasion in glioma cells. Various significant advancements in transcriptomic profiling studies have enabled the identification of immune-related long non-coding RNAs as immune cell-specific gene expression regulators that mediates both stimulatory and suppressive immune responses, implying lncRNAs as potential candidates for improving immunotherapy efficacy against tumors and due to the lack of different diagnostic and treatments for glioma, lncRNAs are potential candidates to be used as future diagnostic, prognostic biomarker and treatment tools for glioma. This review’s primary purpose is to concentrate on the role of long non-coding RNAs in early glioma identification, treatment, and immunotherapy.

The lncRNAs at X Chromosome Inactivation Center: Not Just a Matter of Sex Dosage Compensation

Non-coding RNAs (ncRNAs) constitute the majority of the transcriptome, as the result of pervasive transcription of the mammalian genome. Different RNA species, such as lncRNAs, miRNAs, circRNA, mRNAs, engage in regulatory networks based on their reciprocal interactions, often in a competitive manner, in a way denominated “competing endogenous RNA (ceRNA) networks” (“ceRNET”): miRNAs and other ncRNAs modulate each other, since miRNAs can regulate the expression of lncRNAs, which in turn regulate miRNAs, titrating their availability and thus competing with the binding to other RNA targets. The unbalancing of any network component can derail the entire regulatory circuit acting as a driving force for human diseases, thus assigning “new” functions to “old” molecules. This is the case of XIST, the lncRNA characterized in the early 1990s and well known as the essential molecule for X chromosome inactivation in mammalian females, thus preventing an imbalance of X-linked gene expression between females and males. Currently, literature concerning XIST biology is becoming dominated by miRNA associations and they are also gaining prominence for other lncRNAs produced by the X-inactivation center. This review discusses the available literature to explore possible novel functions related to ceRNA activity of lncRNAs produced by the X-inactivation center, beyond their role in dosage compensation, with prospective implications for emerging gender-biased functions and pathological mechanisms.

LncRNA FTX promotes the malignant progression of colorectal cancer by regulating the miR-214-5p-JAG1 axis

Background

Long non-coding RNAs (lncRNAs) have recently been found to be vital regulators of various cancers, including colorectal cancer (CRC). It has been previously reported that the dysregulated expression of lncRNA Five prime to Xist (FTX) is involved in carcinogenesis. However, the role of lncRNA FTX in the progression of CRC is still unclear.

Methods

Fluorescence in situ hybridization (FISH) was used to detect the expression of lncRNA FTX and miR-214-5p in CRC tissues. Cell Counting Kit-8 assay, transwell assay, wound-healing assay, and proliferation assay were used to explore the function of lncRNA FTX in CRC cells. Quantitative real-time polymerase chain reaction (qRT-PCR), western blotting, and luciferase reporter assay were used to confirm the relationship between lncRNA FTX and miR-214-5p-jagged canonical Notch ligand 1 (JAG1). We further explored the role of lncRNA FTX in vivo using xenograft tumor assay.

Results

lncRNA FTX was found to be upregulated in CRC tissues by FISH. The downregulation of endogenous lncRNA FTX expression inhibited CRC cell proliferation, migration, and invasion. Mechanistically, lncRNA FTX sequestered miR-214-5p and thus released its repression on JAG1, driving the malignant progression of CRC.

Conclusions

These findings give rise to a new perspective, the lncRNA FTX-miR-214-5p-JAG1 regulatory axis, in exploring the cancer-promoting mechanism of lncRNA FTX in CRC.

The Function of LncRNA FTX in Several Common Cancers

BACKGROUND

LncRNA is a kind of non-coding RNA and its research is more popular in recent years, which has more than 200 nucleotides. It plays a significant part in various biological functions, including chromosome modification, genome modification, transcriptional activation, transcriptional interference, and other processes. FTX, at the center of the X chromosome inactivation and it has been shown that lncRNA FTX regulates cancer cells' development, migration, and invasion in many studies.

METHODS

Relevant literature was collected through the PubMed system search and is summarized in this article.

RESULTS

LncRNA FTX abnormally increased in tumor cells, such as liver cancer, stomach cancer, leukemia, renal cell carcinoma, colorectal cancer, glioma, osteosarcoma, etc. However, the expression level decreased in temporal lobe epilepsy, liver cirrhosis, heart failure, etc. Conclusion: FTX may be an important regulatory factor and a potential therapeutic target in cancers.

Upregulation of FTX expression is associated with a poor prognosis and contributes to the progression of thyroid cancer

The dysregulated expression of long non-coding RNA FTX transcript X inactive specific transcript regulator (FTX) has been reported to be involved in the tumorigenesis of multiple cancer types. However, to the best our knowledge, its function and clinical value in thyroid cancer remain unclear. The present study aimed to determine the potential role of FTX in the development and progression of thyroid cancer. Reverse transcription-quantitative PCR analysis revealed that the expression levels of FTX were upregulated in thyroid cancer tissues and cell lines compared with those in normal tissues and cell lines, respectively. Survival analysis demonstrated that patients with upregulated FTX expression had a lower survival rate. Functional experiments revealed that the knockdown of FTX inhibited proliferation, cell cycle progression, migration and invasion, and induced apoptosis in thyroid cancer cells, while FTX overexpression accelerated proliferation, migration and invasion, and alleviated apoptosis in thyroid cancer cells. In addition, FTX knockdown significantly inhibited tumor growth in vivo. Furthermore, in thyroid cancer cells, FTX was identified to positively regulate the expression levels of TGF-β1, which is known to play an important regulatory role in tumor metastasis. In conclusion, the findings of the present study suggested that FTX may accelerate thyroid cancer progression via regulation of cellular activities, including cell proliferation, migration, invasion and apoptosis. Thus, FTX may represent a potential biomarker for the diagnosis, treatment and prognosis of thyroid cancer.

Astrocyte elevated gene-1 (AEG-1): A key driver of hepatocellular carcinoma (HCC)

An array of human cancers, including hepatocellular carcinoma (HCC), overexpress the oncogene Astrocyte elevated gene-1 (AEG-1). It is now firmly established that AEG-1 is a key driver of carcinogenesis, and enhanced expression of AEG-1 is a marker of poor prognosis in cancer patients. In-depth studies have revealed that AEG-1 positively regulates different hallmarks of HCC progression including growth and proliferation, angiogenesis, invasion, migration, metastasis and resistance to therapeutic intervention. By interacting with a plethora of proteins as well as mRNAs, AEG-1 regulates gene expression at transcriptional, post-transcriptional, and translational levels, and modulates numerous pro-tumorigenic and tumor-suppressive signal transduction pathways. Even though extensive research over the last two decades using various in vitro and in vivo models has established the pivotal role of AEG-1 in HCC, effective targeting of AEG-1 as a therapeutic intervention for HCC is yet to be achieved in the clinic. Targeted delivery of AEG-1 small interfering ribonucleic acid (siRNA) has demonstrated desired therapeutic effects in mouse models of HCC. Peptidomimetic inhibitors based on protein-protein interaction studies has also been developed recently. Continuous unraveling of novel mechanisms in the regulation of HCC by AEG-1 will generate valuable knowledge facilitating development of specific AEG-1 inhibitory strategies. The present review describes the current status of AEG-1 in HCC gleaned from patient-focused and bench-top studies as well as transgenic and knockout mouse models. We also address the challenges that need to be overcome and discuss future perspectives on this exciting molecule to transform it from bench to bedside.

Multifunctional Role of Astrocyte Elevated Gene-1 (AEG-1) in Cancer: Focus on Drug Resistance

Simple Summary

Chemotherapy is a major mode of treatment for cancers. However, cancer cells adapt to survive in stressful conditions and in many cases, they are inherently resistant to chemotherapy. Additionally, after initial response to chemotherapy, the surviving cancer cells acquire new alterations making them chemoresistant. Genes that help adapt the cancer cells to cope with stress often contribute to chemoresistance and one such gene is Astrocyte elevated gene-1 (AEG-1). AEG-1 levels are increased in all cancers studied to date and AEG-1 contributes to the development of highly aggressive, metastatic cancers. In this review, we provide a comprehensive description of the mechanism by which AEG-1 augments tumor development with special focus on its ability to regulate chemoresistance. We also discuss potential ways to inhibit AEG-1 to overcome chemoresistance.

Abstract

Cancer development results from the acquisition of numerous genetic and epigenetic alterations in cancer cells themselves, as well as continuous changes in their microenvironment. The plasticity of cancer cells allows them to continuously adapt to selective pressures brought forth by exogenous environmental stresses, the internal milieu of the tumor and cancer treatment itself. Resistance to treatment, either inherent or acquired after the commencement of treatment, is a major obstacle an oncologist confronts in an endeavor to efficiently manage the disease. Resistance to chemotherapy, chemoresistance, is an important hallmark of aggressive cancers, and driver oncogene-induced signaling pathways and molecular abnormalities create the platform for chemoresistance. The oncogene Astrocyte elevated gene-1/Metadherin (AEG-1/MTDH) is overexpressed in a diverse array of cancers, and its overexpression promotes all the hallmarks of cancer, such as proliferation, invasion, metastasis, angiogenesis and chemoresistance. The present review provides a comprehensive description of the molecular mechanism by which AEG-1 promotes tumorigenesis, with a special emphasis on its ability to regulate chemoresistance.

Silencing of FTX suppresses pancreatic cancer cell proliferation and invasion by upregulating miR-513b-5p

BACKGROUND

Abnormal expression of long non-coding RNA (lncRNA) FTX (five prime to Xist), which is involved in X chromosome inactivation, has been reported in various tumors. However, the effect of FTX on the development of pancreatic cancer (PC) has not been elucidated. The purpose of this study was to explore the possible molecular mechanism of FTX in PC.

METHODS

Quantitative real-time PCR (qRT-PCR) was used to measure the expression levels of FTX and miR-513b-5p in PC cell lines. Proliferation and apoptosis of PC cells were determined by CCK-8, Edu assay, and flow cytometry. Invasion and migration ability of PC cells were detected by Transwell assay and scratch test. Bioinformatics analysis, luciferase reporter gene assay, and RNA immunoprecipitation (RIP) assay were used to verify the direct binding between FTX and miR-513b-5p. The xenotransplantation mouse model was established to explore the effect of FTX and miR-513b-5p on the PC tumor growth in vivo.

RESULTS

The expression levels of FTX were increased in PC cell lines, and silencing of FTX remarkably suppressed the invasion ability and cell viability. Besides, FTX could bind to miR-513b-5p as a competitive endogenous RNA, thus promoting the invasion and proliferation ability of PC cells. Moreover, knockdown of FTX inhibited the tumor growth and increased the expression levels of miR-513b-5p and apoptosis-related proteins in vivo.

CONCLUSIONS

FTX could directly combine with miR-513b-5p as a competitive endogenous RNA, thus promoting the occurrence and development of PC in vitro and in vivo.

Novel insights into the interaction between long non-coding RNAs and microRNAs in glioma

Glioma is the most common brain tumor of the central nervous system. Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) have been identified to play a vital role in the initiation and progression of glioma, including tumor cell proliferation, survival, apoptosis, invasion, and therapy resistance. New documents emerged, which indicated that the interaction between long non-coding RNAs and miRNAs contributes to the tumorigenesis and pathogenesis of glioma. LncRNAs can act as competing for endogenous RNA (ceRNA), and molecular sponge/deregulator in regulating miRNAs. These interactions stimulate different molecular signaling pathways in glioma, including the lncRNAs/miRNAs/Wnt/β-catenin molecular signaling pathway, the lncRNAs/miRNAs/PI3K/AKT/mTOR molecular signaling pathway, the lncRNAs-miRNAs/MAPK kinase molecular signaling pathway, and the lncRNAs/miRNAs/NF-κB molecular signaling pathway. In this paper, the basic roles and molecular interactions of the lncRNAs and miRNAs pathway glioma were summarized to better understand the pathogenesis and tumorigenesis of glioma.

Long non-coding RNA FTX predicts a poor prognosis of human cancers: a meta-analysis

Background: Several studies have assessed the relationship between long non-coding RNA five prime to Xist (FTX) expression, clinicopathological features, and survival outcomes in patients with cancer with conflicting results. This meta-analysis synthesized existing data to clarify the association between FTX with cancer prognosis.

Methods: PubMed, Embase, Cochrane library, Web of Science, Chinese CNKI, and the Chinese WanFang databases were used to search for relevant studies. The role of FTX in cancers was evaluated by pooled odds ratios (ORs) and hazard ratios (HRs) with 95% confidence intervals (CIs).

Results: Eleven studies comprising 1210 participants including colorectal cancer (CRC), hepatocellular carcinoma (HCC), gastric cancer (GC), renal cell carcinoma (RCC), osteosarcoma (OSC), and glioma were enrolled in this analysis. The meta-analysis showed that high FTX expression was significantly associated with several clinicopathological characteristics, including lymph node metastasis in patients with CRC, GC, HCC, and RCC, distant metastasis in patients with CRC, GC, HCC, and OSC, larger tumor size in patients with CRC, GC, HCC, RCC, and OSC, and subsequently TNM/clinical stage in patients with CRC, GC, HCC, OSC, and glioma. The pooled results from the survival analysis revealed a significant correlation between high FTX expression and shorter OS in patients with HCC, CRC, GC, OSC, and glioma. Further, FTX overexpression could be an independent predictive marker for shorter OS in patients with CRC, HCC, OSC, and glioma.

Conclusions: FTX may be a potential oncogene, with high FTX expression being associated with a poorer prognosis in patients with CRC, HCC, OSC, and glioma.

Long noncoding RNA FTX ameliorates hydrogen peroxide-induced cardiomyocyte injury by regulating the miR-150/KLF13 axis

Background

Myocardial reperfusion is an effective therapy for acute myocardial infarction (AMI). However, ischemia/reperfusion (I/R) injury following myocardial reperfusion is a significant limitation for AMI treatment. Five prime to Xist (FTX) was recognized as a biomarker of multiple diseases, including heart disease. However, the molecular mechanism of FTX in I/R injury is unclear.

Methods

Cell viability was evaluated by using cell counting kit-8 (CCK-8) assay. Apoptosis was analyzed by using a caspase-3 activity detection kit and flow cytometry. The expression of FTX, microRNA (miR)-150, and Kruppel-like factor 13 (KLF13) was measured by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The interaction of miR-150 and FTX or KLF13 was confirmed by a dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. Protein expression of KLF13 was examined by Western blot. The role of FTX was detected in I/R-injured heart tissues in vivo.

Results

Hydrogen peroxide (H₂O₂) induced cardiomyocyte injury by decreasing cell viability and expediting cell apoptosis. However, FTX alleviated cardiomyocyte injury by promoting cell proliferation and restricting cell apoptosis of H9C2 cells that were treated with H₂O₂. In addition, we discovered that FTX directly interacted with miR-150, while KLF13 was a target of miR-150. Rescue experiments showed that miR-150 neutralized the FTX-mediated promotion of cell progression and restriction of cell apoptosis in H9C2 cells treated with H₂O₂. KLF13 knockdown restored the effect of miR-150 on increased proliferation and decrease in apoptosis in H₂O₂-treated cardiomyocytes. Furthermore, FTX enhanced the expression of KLF13 protein through interaction with miR-150. Upregulation of FTX repressed apoptosis in I/R-injured heart tissues in vivo.

Conclusion

FTX relieves H₂O₂-induced cardiomyocyte injury by increasing KLF13 expression via depletion of miR-150, thus providing a novel therapeutic target for the alleviation of I/R injury.

Downregulation of Long Noncoding RNA TUG1 Attenuates MTDH-Mediated Inflammatory Damage via Targeting miR-29b-1-5p After Spinal Cord Ischemia Reperfusion

Long noncoding RNAs and microRNAs (miRNAs) play a vital role in spinal cord ischemia reperfusion (IR) injury. The aim of this study was to identify the potential interactions between taurine upregulated gene 1 (TUG1) and miRNA-29b-1-5p in a rat model of spinal cord IR. The IR injury was established by 14-minute occlusion of aortic arch. TUG1 and metadherin (MTDH) knockdown were induced by respective siRNAs, and miR-29b-1-5p expression was modulated using specific inhibitor or mimics. The interactions between TUG1, miR-29b-1-5p, and the target genes were determined using the dual-luciferase reporter assay. We found that IR respectively downregulated and upregulated miR-29b-1-5p and TUG1, and significantly increased MTDH expression. MTDH was predicted as a target of miR-29b-1-5p and its knockdown downregulated NF-κB and IL-1β levels. A direct interaction was observed between TUG1 and miR-29b-1-5p, and knocking down TUG1 upregulated the latter. Furthermore, overexpression of miR-29b-1-5p or knockdown of TUG1 alleviated blood-spinal cord barrier leakage and improved hind-limb motor function by suppressing MTDH and its downstream pro-inflammatory cytokines. Knocking down TUG1 also alleviated MTDH/NF-κB/IL-1β pathway-mediated inflammatory damage after IR by targeting miR-29b-1-5p, whereas blocking the latter reversed the neuroprotective effect of TUG1 knockdown and restored MTDH/NF-κB/IL-1β levels.

Systematic Analysis of Intronic miRNAs Reveals Cooperativity within the Multicomponent FTX Locus to Promote Colon Cancer Development

Approximately half of all miRNA reside within intronic regions and are often cotranscribed with their host genes. However, most studies of intronic miRNA focus on individual miRNA, while conversely most studies of protein-coding and noncoding genes frequently ignore any intron-derived miRNA. We hypothesize that the individual components of such multigenic loci may play cooperative or competing roles in driving disease progression and that examining the combinatorial effect of these components would uncover deeper insights into their functional importance. To address this, we performed systematic analyses of intronic miRNA:host loci in colon cancer. The FTX locus, comprising of a long noncoding RNA FTX and multiple intronic miRNA, was highly upregulated in cancer, and cooperativity within this multicomponent locus promoted cancer growth. FTX interacted with DHX9 and DICER and regulated A-to-I RNA editing and miRNA expression. These results show for the first time that a long noncoding RNA can regulate A-to-I RNA editing, further expanding the functional repertoire of long noncoding RNA. Intronic miR-374b and miR-545 inhibited tumor suppressors PTEN and RIG-I to enhance proto-oncogenic PI3K-AKT signaling. Furthermore, intronic miR-421 may exert an autoregulatory effect on miR-374b and miR-545. Taken together, our data unveil the intricate interplay between intronic miRNA and their host transcripts in the modulation of key signaling pathways and disease progression, adding new perspectives to the functional landscape of multigenic loci. SIGNIFICANCE: This study illustrates the functional relationships between individual components of multigenic loci in regulating cancer progression.See related commentary by Calin, p. 1212.

De Novo A-to-I RNA Editing Discovery in lncRNA

Simple Summary

Long non-coding RNAs are emerging as key regulators of gene expression at both transcriptional and translational levels, and their alterations (in expression or sequence) are linked to tumorigenesis and tumor progression. RNA editing has the unique ability to change the RNA sequence without altering the integrity or sequence of genomic DNA, with adenosine to inosine (A-to-I) RNA editing being the most common event in humans. With the ability to change the genetic information after transcription, RNA editing is an essential player in the transcriptome and proteome enrichment; however, when deregulated, it can contribute to cell transformation. In this article, we performed the first deep de novo editing survey in lncRNA, demonstrating that RNA editing is a pervasive phenomenon involving lncRNAs important in the brain and brain cancer. Our study will open a new field of research in which the interplay between lncRNA and RNA editing can add novel insights into cancer.

Abstract

Background: Adenosine to inosine (A-to-I) RNA editing is the most frequent editing event in humans. It converts adenosine to inosine in double-stranded RNA regions (in coding and non-coding RNAs) through the action of the adenosine deaminase acting on RNA (ADAR) enzymes. Long non-coding RNAs, particularly abundant in the brain, account for a large fraction of the human transcriptome, and their important regulatory role is becoming progressively evident in both normal and transformed cells. Results: Herein, we present a bioinformatic analysis to generate a comprehensive inosinome picture in long non-coding RNAs (lncRNAs), using an ad hoc index and searching for de novo editing events in the normal brain cortex as well as in glioblastoma, a highly aggressive human brain cancer. We discovered >10,000 new sites and 335 novel lncRNAs that undergo editing, never reported before. We found a generalized downregulation of editing at multiple lncRNA sites in glioblastoma samples when compared to the normal brain cortex. Conclusion: Overall, our study discloses a novel layer of complexity that controls lncRNAs in the brain and brain cancer.

The long noncoding RNA FTX promotes a malignant phenotype in bone marrow mesenchymal stem cells via the miR-186/c-Met axis

Gliomas are the most common and aggressive primary tumours of the central nervous system in adults. Bone marrow-derived mesenchymal stem cells (BMSCs) are an important component of the glioma microenvironment. Our previous study indicated that BMSCs in the glioma microenvironment could be induced to malignantly transform by glioma stem cells (GSCs). The malignant transformation of BMSCs is closely related to glioma progression; however, the underlying mechanism of this transformation has not been fully clarified. In this study, we found that compared with the levels in normal BMSCs, the levels of the long noncoding RNA FTX transcript XIST regulator (lncRNA-FTX) were increased in malignantly transformed BMSCs (tBMSCs), which was associated with the proliferation, migration and invasion of tBMSCs. Next, by using a luciferase reporter assay and an RNA pull-down assay, we found that lncRNA-FTX acted as a sponge for miR-186 in tBMSCs. Further research revealed that miR-186 could bind to the 3'-UTR (untranslated region) of c-Met, which acts as an oncogene in gliomas. Through functional assays, we showed that lncRNA-FTX could regulate c-Met expression in tBMSCs in a miR-186-dependent manner. Based on these data, we concluded that lncRNA-FTX plays a key role in the GSC-mediated malignant transformation of BMSCs in the glioma microenvironment, which is of great significance for further understanding the pathogenesis of glioma.

LncRNA SNHG7 promotes glioma cells viability, migration and invasion by regulating miR-342-3p/AKT2 axis

PURPOSE

Glioma has been categorized as the most common primary malignant brain tumor. Long non-coding RNA SNHG7 (lncRNA SNHG7) has been recognized in various cancers as a possible oncogene. In this study, the effect of SNHG7 on glioma cells was investigated.

MATERIALS AND METHODS

Thirty glioma tissues and adjacent normal tissues were collected. Pc-SNHG7, sh-SNHG7, miR-342-3p mimic and miR-342-3p inhibitor were transfected into the glioma cells. Cell Counting Kit-8, Transwell and scratch assay evaluated glioma cells viability, invasion and migration, respectively. TargetScan, Starbase and dual-luciferase reporter were used to predict and confirm the target genes and potential binding sites of SNHG7, miR-342-3p and AKT2. Relative miR-342-3p and AKT2 expressions were assessed by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. Pearson's analysis was adopted for correlation analysis between SNHG7, miR-342-3p and AKT2.

RESULTS

SNHG7 expressions in glioma tissues and cells were increased, upregulation of SNHG7 promotes cell viability, invasion and migration. SNHG7 was shown to bind with miR-342-3p, and upregulating SNHG7 reduced miR-342-3p expression. AKT2 was the target gene of miR-342-3p, and miR-342-3p expression was decreased while AKT2 expression was increased in glioma tissues. High expression of miR-342-3p inhibited cell viability, invasion and migration and reduced AKT2 expression, whereas low expression of miR-342-3p did the opposite effect.

CONCLUSIONS

Upregulating SNHG7 might promote glioma cells viability, migration and invasion with the regulation of decreasing miR-342-3p level and increasing AKT2 level.

Expression of microRNAs in plasma and in extracellular vesicles derived from plasma for dogs with glioma and dogs with other brain diseases

OBJECTIVE

To measure expression of microRNAs (miRNAs) in plasma and in extracellular vesicles (EVs) derived from plasma for dogs with glioma and dogs with other brain diseases.

SAMPLE

Plasma samples from 11 dogs with glioma and 19 control dogs with various other brain diseases.

PROCEDURES

EVs were isolated from plasma samples by means of ultracentrifugation. Expression of 4 candidate reference miRNAs (let-7a, miR-16, miR-26a, and miR-103) and 4 candidate target miRNAs (miR-15b, miR-21, miR-155, and miR-342-3p) was quantified with reverse transcription PCR assays. Three software programs were used to select the most suitable reference miRNAs from among the 4 candidate reference miRNAs. Expression of the 4 target miRNAs was then calculated relative to expression of the reference genes in plasma and EVs, and relative expression was compared between dogs with glioma and control dogs with other brain diseases.

RESULTS

The most suitable reference miRNAs were miR-16 for plasma and let-7a for EVs. Relative expression of miR-15b in plasma and in EVs was significantly higher in dogs with glioma than in control dogs. Relative expression of miR-342-3p in EVs was significantly higher in dogs with glioma than in control dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that miR-15b and miR-342-3p have potential as noninvasive biomarkers for differentiating glioma from other intracranial diseases in dogs. However, more extensive analysis of expression in specific glioma subtypes and grades, compared with expression in more defined control populations, will be necessary to assess their clinical relevance.

Long noncoding RNA FTX is associated with prognosis of glioma patients

Background

Long noncoding RNAs play influential roles in the progression of many types of human malignancies. The present study aimed to explore the prognostic value of long noncoding RNA FTX (FTX) on patients with glioma.

Methods

FTX expression in glioma specimens and matched adjacent non‐neoplasm specimens was examined by a quantitative real‐time polymerase chain reaction assay. Furthermore, assays of the relationships between FTX expression and clinicopathologic characteristics of patients with glioma were also performed. Kaplan–Meier methods were applied for the assays of the overall survival (OS) and progression‐free survival (PFS) of patients and Cox regression assays were used to analyze the clinical value of FTX used as a possible biomarker.

Results

FTX levels were significantly up‐regulated in glioma specimens compared to the paired non‐neoplasm specimens (p < 0.01). Furthermore, high FTX expression in neoplasm tissues was dramatically associated with World Health Organization grade (p = 0.001) and Karnofsky Performance Score (p = 0.009). Kaplan–Meier assays with 187 patients revealed that patients with high level of FTX expression displayed poorer OS (p = 0.002) and PFS (p = 0.000). Subsequently, multivariable Cox regression analysis identified FTX expression as an independent prognostic factor of unfavorable survivals in glioma (OS: p = 0.001; PFS: p = 0.002).

Conclusions

These findings indicated that FTX may be a novel predictor for prognostic assessment of glioma patients. However, studies conducted with larger numbers of patients are essential to confirm our findings.

Genomic analyses of early responses to radiation inglioblastoma reveal new alterations at transcription,splicing, and translation levels

High-dose radiation is the main component of glioblastoma therapy. Unfortunately, radio-resistance is a common problem and a major contributor to tumor relapse. Understanding the molecular mechanisms driving response to radiation is critical for identifying regulatory routes that could be targeted to improve treatment response. We conducted an integrated analysis in the U251 and U343 glioblastoma cell lines to map early alterations in the expression of genes at three levels: transcription, splicing, and translation in response to ionizing radiation. Changes at the transcriptional level were the most prevalent response. Downregulated genes are strongly associated with cell cycle and DNA replication and linked to a coordinated module of expression. Alterations in this group are likely driven by decreased expression of the transcription factor FOXM1 and members of the E2F family. Genes involved in RNA regulatory mechanisms were affected at the mRNA, splicing, and translation levels, highlighting their importance in radiation-response. We identified a number of oncogenic factors, with an increased expression upon radiation exposure, including BCL6, RRM2B, IDO1, FTH1, APIP, and LRIG2 and lncRNAs NEAT1 and FTX. Several of these targets have been previously implicated in radio-resistance. Therefore, antagonizing their effects post-radiation could increase therapeutic efficacy. Our integrated analysis provides a comprehensive view of early response to radiation in glioblastoma. We identify new biological processes involved in altered expression of various oncogenic factors and suggest new target options to increase radiation sensitivity and prevent relapse.

Integrated analysis of lymphocyte infiltration-associated lncRNA for ovarian cancer via TCGA, GTEx and GEO datasets

Background

Abnormal expression of long non-coding RNAs (lncRNA) play a significant role in the incidence and progression of high-grade serous ovarian cancer (HGSOC), which is a leading cause of mortality among gynecologic malignant tumor patients. In this study, our aim is to identify lncRNA-associated competing endogenous RNA (ceRNA ) axes that could define more reliable prognostic parameters of HGSOC, and to investigate the lncRNAs’ potential mechanism of in lymphocyte infiltration.

Methods

The RNA-seq and miRNA expression profiles were downloaded from The Cancer Genome Atlas (TCGA) and the Genotype-Tissue Expression (GTEx) database; while for obtaining the differentially expressed lncRNAs (DELs), miRNAs (DEMs), and genes (DEGs), we used edgeR, limma and DESeq2. After validating the RNA, miRNA and gene expressions, using integrated three RNA expression profiles (GSE18520, GSE27651, GSE54388) and miRNA profile (GSE47841) from the Gene Expression Omnibus (GEO) database, we performed Gene Ontology (GO) and Kyoto Encyclopedia of Gene and Genome (KEGG) pathway analyses through ClusterProfiler. The prognostic value of these genes was determined with Kaplan–Meier survival analysis and Cox regression analysis. The ceRNA network was constructed using Cytoscape. The correlation between lncRNAs in ceRNA network and immune infiltrating cells was analyzed by using Tumor IMmune Estimation Resource (TIMER), and gene markers of tumor-infiltrating immune cells were identified using Spearman’s correlation after removing the influence of tumor purity.

Results

A total of 33 DELs (25 upregulated and eight downregulated), 134 DEMs (76 upregulated and 58 downregulated), and 1,612 DEGs (949 upregulated and 663 downregulated) were detected that could be positively correlated with overall survival (OS) of HGSOC. With the 1,612 analyzed genes, we constructed a ceRNA network, which indicated a pre-dominant involvement of the immune-related pathways. Furthermore, our data revealed that LINC00665 influenced the infiltration level of macrophages and dendritic cells (DCs). On the other hand, FTX and LINC00665, which may play their possible roles through the ceRNA axis, demonstrated a potential to inhibit Tregs and prevent T-cell exhaustion.

Conclusion

We defined several prognostic biomarkers for the incidence and progression of HGSOC and constructed a network for ceRNA axes; among which three were indicated to have a positive correlation with lymphocyte infiltration, namely: FTX-hsa-miR-150-5p-STK11, LINC00665-hsa-miR449b-5p-VAV3 and LINC00665-hsa-miR449b-5p-RRAGD.

LncRNA FTX Contributes to the Progression of Colorectal Cancer Through Regulating miR-192-5p/EIF5A2 Axis

Background

Long non-coding RAN five prime to Xist (LncRNA FTX) has been revealed to be a cancer-related lncRNA and implicated in the progression of colorectal cancer (CRC). Besides, miR-192-5p (miR-192) or eukaryotic initiation factor 5A2 (EIF5A2) also was identified to link with the tumorigenesis of CRC. Here, we further explored the function of FTX and the regulatory relationship among FTX, miR-192 and EIF5A2 in CRC progression.

Methods

Levels of FTX, miR-192-5p and EIF5A2 were detected by quantitative real-time polymerase chain reaction (qRT-PCR) or Western blot, respectively. Cell proliferation, apoptosis, migration and invasion were analyzed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometry or transwell assay, respectively. The interaction between miR-192-5p and FTX or EIF5A2 was confirmed by dual-luciferase reporter and pull-down assay. Murine xenograft model was established using LoVo cells transfected with sh-FTX.

Results

FTX was up-regulated in CRC tissues and cell lines, knockdown of FTX inhibited CRC cell proliferation, migration and invasion in vitro as well as suppressed CRC tumor growth in vivo. FTX was confirmed to directly bind to miR-192-5p and negatively regulated miR-192-5p expression in CRC cells. Besides that overexpressed FTX positively modulated EIF5A2, a direct target of miR-192-5p, via miR-192-5p in CRC cells. Importantly, the inhibitory activities on CRC progression mediated by FTX deletion were reversed miR-192-5p down-regulation or EIF5A2 up-regulation.

Conclusion

LncRNA FTX functioned as an oncogene to contribute to CRC progression by regulating miR-192-5p/EIF5A2 axis, providing a novel insight into the pathogenesis of CRC and a promising therapeutic target for CRC treatment.

FTX contributes to cell proliferation and migration in lung adenocarcinoma via targeting miR-335-5p/NUCB2 axis

Background

Extensive studies revealed that long non-coding RNAs (lncRNAs) could act as a regulator in tumors, including lung adenocarcinoma (LUAD). LncRNA FTX transcript, XIST regulator (FTX) has been reported to regulate the biological behaviors of some cancers. Nevertheless, its functional role and molecular mechanism remain obscure in LUAD. Our current study concentrates on exploring the biological function of FTX in LUAD.

Methods

RT-qPCR was used to test the expression of FTX, miR-335-5p or NUCB2 in LUAD cells. The effect of FTX on LUAD progression was investigated by colony formation, EdU, flow cytometry, TUNEL, transwell and western blot assays. The interaction between microRNA-335-5p (miR-335-5p) and FTX or nucleobindin 2 (NUCB2) was confirmed by luciferase reporter assay.

Results

RT-qPCR showed that FTX expression was up-regulated in LUAD cell lines. Loss-of-function assay indicated that FTX accelerated cell proliferation, migration and invasion, while inhibited cell apoptosis in LUAD. Besides, miR-335-5p, lowly expressed in LUAD cells, was discovered to be sponged by FTX. Subsequently, NUCB2 was identified as a target gene of miR-335-5p. Additionally, it was confirmed that NUCB2 functioned as an oncogene in LUAD. Rescue assays indicated that LUAD progression inhibited by FTX knockdown could be restored by NUCB2 up-regulation.

Conclusion

FTX played an oncogenic role in LUAD and contributed to cancer development via targeting miR-335-5p/NUCB2 axis.

Long Noncoding RNA FTX Reduces Hypertrophy of Neonatal Mouse Cardiac Myocytes and Regulates the PTEN/PI3K/Akt Signaling Pathway by Sponging MicroRNA-22

BACKGROUND Cardiac myocyte hypertrophy results from clinical conditions that include hypertension and valvular heart disease, and can result in heart failure. This study aimed to investigate the expression and role of the long noncoding RNA FTX (lnc-FTX), an X-inactive-specific transcript (XIST) regulator transcribed from the X chromosome, in hypertrophy of neonatal mouse cardiac myocytes induced by angiotensin II (Ang II) in vitro. MATERIAL AND METHODS Cardiac myocytes were isolated from neonatal mice and cultured with and without Ang II. Immunofluorescence, with localization of an antibody to alpha-smooth muscle actin (alpha-SMA), was used to identify the neonatal mouse cardiac myocytes. Quantitative real-time polymerase chain reaction (qRT-PCR) measured gene expression levels. The cell counting kit-8 (CCK-8) assay was used to determine cell viability, and Western blot measured protein expression. StarBase v2.0 bioinformatics software was used for target gene prediction and was confirmed with the luciferase reporter assay. RESULTS The expression of lnc-FTX was reduced in mouse cardiac myocytes treated with Ang II. Overexpression of lnc-FTX reduced cell apoptosis, cardiomyocyte contractility, and the expression of c-Jun, A-type natriuretic peptide (ANP), and B-type natriuretic peptide (BNP) induced by Ang II. The target of lnc-FTX was micro-RNA 22 (miRNA-22). The mechanism of action of lnc-FTX in neonatal mouse cardiac myocytes was through suppression of the PI3K/Akt signaling pathway by promoting the release of PTEN by sponging miRNA-22. CONCLUSIONS The expression of lnc-FTX was associated with reduced hypertrophy of neonatal mouse cardiac myocytes and regulated the PTEN/PI3K/Akt signaling pathway by sponging miRNA-22.

Quantitative Proteomics Analysis Revealed the Potential Role of lncRNA Ftx in Promoting Gastric Cancer Progression

PURPOSE

The molecular pathogenesis of gastric cancer is still ambiguous till now. Here, it is demonstrated that long noncoding RNA (lncRNA) Ftx acts as a novel tumor promotor of gastric cancer and a potent regulator of hexokinase-2 (HK2).

EXPERIMENTAL DESIGN

The role of lncRNA Ftx is detected in the loss and gain-of-function models of gastric cancer cells. Tandem mass tags combined with multidimensional LC and MS analyses are performed to decipher comparative proteomic profiles of gastric cancer cells in response to lncRNA Ftx knockdown and overexpression. Real-time roteomics-clinical applications (PCR) and western blot are used to validate the proteomic data.

RESULTS

A total of 5124 proteins are quantified and indicated in diverse biological functions and metabolic related signaling pathways. Interestingly, HK2, which is downregulated when lncRNA Ftx is deleted and upregulated while lncRNA Ftx is overexpressed, is further validated in gastric cancer cells.

CONCLUSIONS AND CLINICAL RELEVANCE

The present study suggests lncRNA Ftx promotes gastric cancer progression by upregulating HK2, which provides a new perspective for the mechanism of gastric cancer progression, and thus identifies potential therapeutic targets for gastric cancer.

Long Non-Coding RNAs and Related Molecular Pathways in the Pathogenesis of Epilepsy

Epilepsy represents one of the most common neurological disorders characterized by abnormal electrical activity in the central nervous system (CNS). Recurrent seizures are the cardinal clinical manifestation. Although it has been reported that the underlying pathological processes include inflammation, changes in synaptic strength, apoptosis, and ion channels dysfunction, currently the pathogenesis of epilepsy is not yet completely understood. Long non-coding RNAs (lncRNAs), a class of long transcripts without protein-coding capacity, have emerged as regulatory molecules that are involved in a wide variety of biological processes. A growing number of studies reported that lncRNAs participate in the regulation of pathological processes of epilepsy and they are dysregulated during epileptogenesis. Moreover, an aberrant expression of lncRNAs linked to epilepsy has been observed both in patients and in animal models. In this review, we summarize latest advances concerning the mechanisms of action and the involvement of the most dysregulated lncRNAs in epilepsy. However, the functional roles of lncRNAs in the disease pathogenesis are still to be explored and we are only at the beginning. Additional studies are needed for the complete understanding of the underlying mechanisms and they would result in the use of lncRNAs as diagnostic biomarkers and novel therapeutic targets.

Mechanism of microRNA-431-5p-EPB41L1 interaction in glioblastoma multiforme cells

INTRODUCTION

Glioblastoma multiforme (GBM) is a kind of malignant brain tumor prevalent in adults, with the characteristics well adapted to poorly immunogenic and hypoxic conditions. Effective treatment of GBM is impeded due to the high proliferation, migration and invasion of GBM cells. GBM cells migrate by degrading the extracellular matrix, so it is difficult to have GBM cells eradicated completely by surgery. This study aims to confirm that miR-431-5p could influence the proliferation, invasion and migration of human glioblastoma multiforme cells by targeting EPB41L1 (erythrocyte membrane protein band 4.1).

MATERIAL AND METHODS

The expression levels of miR-431-5p and EPB41L1 were detected in GBM cells and tissues using qRT-PCR. Dual luciferase reporter gene assay and western blot were applied to confirm the targeting relationship between miR-431-5p and EPB41L1. GBM cell line U87 was used in MTT, flow cytometry, Transwell, and wound healing assays to determine cell proliferation, migration and invasion.

RESULTS

MiR-431-5p was overexpressed in GBM tissues while EPB41L1 was under-expressed. The results of dual luciferase reporter gene assay and western blot demonstrated that miR-431-5p could target EPB41L1 and suppress its expression. Down-regulating the expression of miR-431-5p or up-regulating the expression of EPB41L1 could inhibit the proliferation, invasion and migration but promote the apoptosis of GBM cells.

CONCLUSIONS

MiR-431-5p facilitated the progression of GBM by inhibiting EPB41L1 expression.

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.

UPF1 regulates the malignant biological behaviors of glioblastoma cells via enhancing the stability of Linc-00313

There is growing evidence that the long non-coding RNAs(lncRNAs) play an important role in the biological behaviors of glioblastoma cells. In this study, we elucidated the function and possible effect and molecular mechanisms of lncRNA-Linc-00313 on the biological behaviors of glioblastoma cells as well as UPF1 function as a RNA-binding protein to enhance its stability. Here, we used qRT-PCR and western blot to measure the expression, cell Transfection to disrupt the expression of genes, cell viability analysis, quantization of apoptosis, cell migration, and invasion assays, Reporter vectors construction and luciferase assays to investigate the malignant biological behaviors of cells, human lncRNA microarrays, RNA-Immunoprecipitation, dual-luciferase gene reporter assay, half-life assay and chromatin immunoprecipitation to verify the binding sites, tumor xenograft implantation for in vivo experiment, SPSS 18.0 statistical software for data statistics. UPF1 and Linc-00313 were both upregulated in glioma tissues and cells. Knockdown of UPF1 or Linc-00313 significantly inhibited malignant biological behaviors of glioma cells by regulating miR-342-3p and miR-485-5p, which are downregulated and functioned as tumor suppressors in glioma. Furthermore, Linc-00313 could acted as a competing endogenous RNA(ceRNA) to regulate the expression of Zic4 by binding to miR-342-3p and miR-485-5p. Interestingly, Zic4 could bind to the promoters of UPF1 and Linc-00313 respectively and upregulate the expression of them. These results indicated that a positive-feedback loop was formed in the regulation of the biological behaviors of glioma cells. The study is the first to prove that the UPF1-Linc-00313-miR-342-3p/miR-485-5p-Zic4-SHCBP1 pathway forms a positive-feedback loop and regulates the biological behaviors of U87 and U251 cells, which might provide a new therapeutic target for glioma.

Differential expression profiles of long noncoding RNAs in synchronous multiple and solitary primary esophageal squamous cell carcinomas: A microarray analysis

As a unique subtype of esophageal cancer, synchronous multiple primary esophageal squamous cell carcinomas (ESCCs) mostly occur in Asian patients with alcohol and/or tobacco abuse, or with a family history of cancer. Multiple ESCCs are associated with poor clinical outcomes. Growing evidence has addressed that long noncoding RNAs (lncRNAs) are involved in the carcinogenesis of various malignancies. We compared the lncRNA and messenger RNA (mRNA) profiles between solitary and multiple ESCC tissues through microarray analysis, aiming at studying their different mechanisms in tumor development. As a result, in multiple ESCCs, a total of 5257 lncRNAs and 3371 mRNAs were consistently differentially expressed compared with solitary ESCC, including 2986 upregulated and 2271 downregulated lncRNAs, and 2313 upregulated, and 1058 downregulated mRNAs. We validated the results in four differentially expressed lncRNAs using quantitative real-time polymerase chain reaction. There were 38 and 20 pathways significantly related to up- and downregulated transcripts. The pathways associated with mostly enriched up- and downregulated mRNAs were hsa01200 (carbon metabolism) and hsa05221 (acute myeloid leukemia- homo sapiens [human]). Gene ontology analysis suggested that upregulated and downregulated mRNAs were mainly enriched in bounding membrane of organelle involved in the cellular component and positive regulation of transport involved in the biological process. Further analysis identified 189 differentially expressed paired antisense lncRNAs and relative sense mRNA, as well as 2134 differentially expressed long intergenic noncoding RNAs and their adjacent mRNA pairs. In conclusion, the aberrantly expressed lncRNAs might play a role in the carcinogenesis of multiple ESCCs and could be candidates as diagnostic biomarkers and therapeutic targets.

microRNA-342-3p targets FOXQ1 to suppress the aggressive phenotype of nasopharyngeal carcinoma cells

Background

microRNA (miR)-342–3p is frequently dysregulated in human cancers. In the present study, we aimed to explore the expression, prognostic significance, and biological relevance of miR-342-3p in nasopharyngeal carcinoma (NPC).

Methods

We examined miR-342-3p expression in 79 paired NPC specimens and corresponding normal tissues and analyzed its prognostic impact on overall survival of NPC patients. Gain- and loss-of-function experiments were conducted to determine the biological roles of miR-342-3p.

Results

Compared with matched normal nasopharyngeal tissues, miR-342-3p was significantly downregulated in NPC (P = 0.0038). Low miR-342-3p expression was significantly correlated with reduced overall survival (P = 0.0084). Ectopic expression of miR-342-3p significantly suppressed proliferation, colony formation, and invasion of NPC cells. In contrast, depletion of miR-342-3p facilitated NPC cell proliferation and invasion. In vivo xenograft studies confirmed that overexpression of miR-342-3p restrained the growth of NPC xenograft tumors. Mechanistically, FOXQ1 served as a functional target of miR-342-3p. There was a significantly negative correlation between miR-342-3p and FOXQ1 expression (r = − 0.487, P = 0.004) in NPC specimens. Overexpression of FOXQ1 rescued the inhibitory effects of miR-342-3p on NPC cell growth and invasion.

Conclusions

miR-342-3p downregulation predicts poor prognosis in NPC patients and shows suppressive activity against NPC growth and invasion through repression of FOXQ1. Restoration of miR-342-3p may represent a potential therapeutic strategy for NPC.

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.

LncRNA FTX sponges miR-215 and inhibits phosphorylation of vimentin for promoting colorectal cancer progression

Recent researches have reported that long noncoding RNA (lncRNA) five prime to Xist (FTX) plays a crucial role in the initiation and progression of cancers. In the current study, the clinical significance and functional roles of lncRNA FTX in colorectal cancer (CRC) progression were investigated. A significant increase of lncRNA FTX expression in CRC tissue and cell lines was observed. Overexpression of lncRNA FTX was significantly associated with the bigger tumor diameter, the advanced TNM stage, the lymph node, and distant metastasis, and also predicted poor prognosis of patients with CRC. Functional analyses demonstrated that knockdown of lncRNA FTX markedly inhibited CRC cell proliferation, migration, and invasion in vitro. Mechanistically, FTX directly interacted with miR-215 and suppressed miR-215 expression. FTX also bind to vimentin and reduced its phosphorylation level on Ser83 in CRC cells. Finally, using siRNAs against lncRNA FTX could dramatically inhibit CRC growth and distant metastasis in vivo. Taken together, our data demonstrated an oncogenic role of lncRNA FTX in CRC tumorigenesis and progression via interaction with miR-215 and vimentin. Then, a promising therapeutic target for CRC was provided.

Aberrant mannosylation profile and FTX/miR-342/ALG3-axis contribute to development of drug resistance in acute myeloid leukemia

Drug-resistance is a major problem in acute myeloid leukemia (AML) chemotherapy. Aberrant changes in specific N-glycans have been observed in leukemia multidrug resistance (MDR). MicroRNAs (miRNAs) and long non coding RNAs (lncRNAs) act as key players in the development of AML resistance to chemotherapy. In the present study, the N-glycan profiles of membrane proteins were analyzed from adriamycin (ADR)-resistant U937/ADR cells and sensitive line U937 cells using mass spectrometry (MS). The composition profiling of high-mannose N-glycans differed in U937/ADR and U937 cell lines. Lectin microarray showed that the strong binding of membrane proteins was observed for MAN-M and ConA lectins, which were specific for mannose. These binding were also validated by flow cytometry. Importantly, the alteration of high-mannose N-glycan was further confirmed by detecting the enzyme level of ALG family. The altered level of ALG3 was found corresponding to the drug-resistant phenotype of AML cell lines both in vitro and in vivo. Mechanistically, miR-342 was found to be dysregulated and inversely correlated to ALG3 expression, targeting its 3'-UTR. LncRNA FTX was a direct target of miR-342 and positively modulated ALG3 expression by competitively binding miR-342 in AML cell lines. Functionally, we found that FTX directly interacted with miR-342 to regulate ALG3 expression and function, including ADR-resistant cell growth and apoptosis. The observation suggested that high-mannose N-glycans and mannosyltransferase ALG3 affected drug-resistance in AML cells. FTX/miR-342/ALG3 axis could potentially be used for the targets to overcome therapeutic resistance in AML.

lncRNA Ftx promotes aerobic glycolysis and tumor progression through the PPARγ pathway in hepatocellular carcinoma

Aerobic glycolysis is a phenomenon by which malignant cells preferentially metabolize glucose through the glycolytic pathway, rather than oxidative phosphorylation to proliferate efficiently. The present study aimed to investigate the expression and functional implications of long non-coding (lnc)RNA Ftx in the aerobic glycolysis and tumorigenesis of hepatocellular carcinoma (HCC). It was identified that lncRNA Ftx was upregulated in human HCC tissues and cell lines and, notably, was associated with aggressive clinicopathological features. lncRNA Ftx overexpression promoted the proliferation, invasion and migration of HCC cells, whereas lncRNA Ftx knockdown resulted in the opposite effects. Furthermore, lncRNA Ftx affected the activity and expression of key enzymes in carbohydrate metabolism, suggesting that lncRNA Ftx may be involved in aerobic glycolysis in HCC. The measurement of glucose consumption, lactate production and glucose transporter expression further supported this assumption. Mechanistically, peroxisome proliferator-activated receptor γ (PPARγ) expression in human HCC tissues and cell lines was positively correlated with lncRNA Ftx. Inhibiting PPARγ in Huh7 cells partially abrogated the alterations in glucose uptake, lactate production and relative glycolytic enzyme expression induced by lncRNA Ftx; similarly, PPARγ activation in Bel-7402 cells partially rescued the lncRNA Ftx-mediated alterations. In conclusion, lncRNA Ftx is a promoter of the Warburg effect and tumor progression, partly via the PPARγ pathway, and may serve as a promising therapeutic target for HCC treatment.

Profiling microRNA from Brain by Microarray in a Transgenic Mouse Model of Alzheimer's Disease

MicroRNAs (miRNAs) are small noncoding RNAs, which regulate numerous cell functions by targeting mRNA for cleavage or translational repression, and have been found to play an important role in Alzheimer's disease (AD). Our study aimed to identify differentially expressed miRNAs in AD brain as a reference of potential therapeutic miRNAs or biomarkers for this disease. We used amyloid precursor protein (APP) and presenilin 1 (PS1) double transgenic mice and age-matched wild-type (WT) littermates to determine the expression of miRNAs in the brain. MiRNAs were profiled by microarray, and differentially expressed miRNAs underwent target prediction and enrichment analysis. Microarray analysis revealed 56 differentially expressed miRNAs in AD mouse brain, which involved 39 miRNAs that were significantly upregulated and 19 that were downregulated at different ages. Among those miRNAs, a total of 11 miRNAs, including miR-342-3p, miR-342-5p, miR-376c-3p, and miR-301b-3p, were not only conserved in human but also predicted to have targets and signaling pathways closely related to the pathology of AD. In conclusion, in this study, differentially expressed miRNAs were identified in AD brain and proposed as biomarkers, which may have the potential to indicate AD progression. Despite being preliminary, these results may aid in investigating pathological hallmarks and identify effective therapeutic targets.

Long non-coding RNAs in hepatocellular carcinoma: Potential roles and clinical implications

Long non-coding RNAs (lncRNAs) are a subgroup of non-coding RNA transcripts greater than 200 nucleotides in length with little or no protein-coding potential. Emerging evidence indicates that lncRNAs may play important regulatory roles in the pathogenesis and progression of human cancers, including hepatocellular carcinoma (HCC). Certain lncRNAs may be used as diagnostic or prognostic markers for HCC, a serious malignancy with increasing morbidity and high mortality rates worldwide. Therefore, elucidating the functional roles of lncRNAs in tumors can contribute to a better understanding of the molecular mechanisms of HCC and may help in developing novel therapeutic targets. In this review, we summarize the recent progress regarding the functional roles of lncRNAs in HCC and explore their clinical implications as diagnostic or prognostic biomarkers and molecular therapeutic targets for HCC.

Upregulation of the long non-coding RNA SNHG1 predicts poor prognosis, promotes cell proliferation and invasion, and reduces apoptosis in glioma

Long non-coding RNAs (lncRNAs), which are non-coding RNAs with a length above 200 nucleotides, have emerged as novel and important gene expression modulators in carcinogenesis. Recent evidence indicates that the lncRNA small nucleolar RNA host gene 1 (SNHG1) functions as an oncogene in several types of human cancers. However, its function in the development of glioma remains unknown. The aim of this research was to investigate the clinical aspects and biological mechanisms of SNHG1 in glioma. SNHG1 expression was measured in glioma tissues and cell lines by quantitative real-time PCR (qRT-PCR). The association between SNHG1 expression in tissues and clinicopathological characteristics and prognosis in glioma patients was also explored. Gain-of-function and loss-of-function studies using SNHG1 cDNA and siRNA, respectively, were used to investigate the role of SNHG1 in cell proliferation, invasion and apoptosis in glioma. SNHG1 was highly expressed in glioma tissues, and its upregulation was closely related to old age. Kaplan-Meier analysis showed that high expression of SNHG1 was significantly associated with poor overall survival (OS). Functionally, ectopic expression of SNHG1 enhanced cell proliferation and cell invasion and reduced cell apoptosis in vitro, while SNHG1 knockdown reversed these effects. Taken together, our findings indicate that SNHG1 functions as an oncogene in glioma and may serve as a novel therapeutic target in future treatments.