Emerging Role of Long Non-Coding RNAs in the Pathobiology of Glioblastoma

LncRNA GAS5 Modulates the Progression of Glioma Through Repressing miR-135b-5p and Upregulating APC

Purpose

The main purpose of this paper is to explore the interaction between GAS5 and miR-135b-5p to understand their function in the metastasis, invasion, and proliferation of glioma. This may provide new ideas for the pathogenesis and treatment of glioma.

Patients and Methods

Western blotting assays and RT‑qPCR were employed to investigate the expression of related genes in glioma tissues or cell lines. CCK-8 was used to examine the impact of GAS5 on cell viability. Motile activities were adopted by the transwell and wound healing experiments. A double luciferase experiment was performed to elucidate transcriptional regulation.

Results

GAS5 showed low expression in glioma cells and tissues, and up-regulation of GAS5 could depress the invasion, proliferation, and metastasis of glioma. GAS5 negatively regulates miR-135b-5p, which can counteract the cellular effects caused by GAS5. APC was the target of miR-135b-5p, and GAS5 can regulate the expression of APC by sponging miR-135b-5p. APC overexpression reversed the effects of miR-135b-5p promotion on glioma cells, while miR-135b-5p has the opposite function. As a downstream target gene of GAS5, miR-135b-5p was negatively regulated by GAS5. The restoration of miR-135b-5p can remarkably reverse the impact of GAS5 on glioma cells. In addition, GAS5 increased the expression of APC in glioma cells by inhibiting miR-135b-5p.

Conclusion

GAS5 increased APC expression by restraining miR-135b-5p and partially blocked the progression of glioma, suggesting that it could be an advantageous therapeutic target for glioma intervention.

A novel disulfidptosis-related gene signature predicts overall survival of glioblastoma patients

Aim: The aim of this study was to investigate the prognostic relevance of disulfidptosis-related genes in glioblastoma using bioinformatic analysis in The Cancer Genome Atlas Program-Glioblastoma (TCGA-GBM) database and develop a gene signature model for predicting patient prognosis. Methods: We conducted a bioinformatic analysis using the TCGA-GBM database and employed weighted co-expression network analysis to identify disulfidptosis-related genes. Subsequently, we developed a predictive gene signature model based on these genes to stratify glioblastoma patients into high and low-risk groups. Results: Patients categorized into the high-risk group based on the disulfidptosis-related gene signature exhibited a significantly reduced survival rate in comparison to those in the low-risk group. Functional analysis also revealed notable differences in the immune status between the two risk groups. Conclusion: In conclusion, a new disulfidptosis-related gene signature can be utilised to predict prognosis in GBM.

lncRNA Biomarkers of Glioblastoma Multiforme

Long noncoding RNAs (lncRNAs) are RNA molecules of 200 nucleotides or more in length that are not translated into proteins. Their expression is tissue-specific, with the vast majority involved in the regulation of cellular processes and functions. Many human diseases, including cancer, have been shown to be associated with deregulated lncRNAs, rendering them potential therapeutic targets and biomarkers for differential diagnosis. The expression of lncRNAs in the nervous system varies in different cell types, implicated in mechanisms of neurons and glia, with effects on the development and functioning of the brain. Reports have also shown a link between changes in lncRNA molecules and the etiopathogenesis of brain neoplasia, including glioblastoma multiforme (GBM). GBM is an aggressive variant of brain cancer with an unfavourable prognosis and a median survival of 14-16 months. It is considered a brain-specific disease with the highly invasive malignant cells spreading throughout the neural tissue, impeding the complete resection, and leading to post-surgery recurrences, which are the prime cause of mortality. The early diagnosis of GBM could improve the treatment and extend survival, with the lncRNA profiling of biological fluids promising the detection of neoplastic changes at their initial stages and more effective therapeutic interventions. This review presents a systematic overview of GBM-associated deregulation of lncRNAs with a focus on lncRNA fingerprints in patients' blood.

Biomolecules to Biomarkers? U87MG Marker Evaluation on the Path towards Glioblastoma Multiforme Pathogenesis

The heterogeneity of the glioma subtype glioblastoma multiforme (GBM) challenges effective neuropathological treatment. The reliance on in vitro studies and xenografted animal models to simulate human GBM has proven ineffective. Currently, a dearth of knowledge exists regarding the applicability of cell line biomolecules to the realm of GBM pathogenesis. Our study's objectives were to address this preclinical issue and assess prominin-1, ICAM-1, PARTICLE and GAS5 as potential GBM diagnostic targets. The methodologies included haemoxylin and eosin staining, immunofluorescence, in situ hybridization and quantitative PCR. The findings identified that morphology correlates with malignancy in GBM patient pathology. Immunofluorescence confocal microscopy revealed prominin-1 in pseudo-palisades adjacent to necrotic foci in both animal and human GBM. Evidence is presented for an ICAM-1 association with degenerating vasculature. Significantly elevated nuclear PARTICLE expression from in situ hybridization and quantitative PCR reflected its role as a tumor activator. GAS5 identified within necrotic GBM validated this potential prognostic biomolecule with extended survival. Here we present evidence for the stem cell marker prominin-1 and the chemotherapeutic target ICAM-1 in a glioma animal model and GBM pathology sections from patients that elicited alternative responses to adjuvant chemotherapy. This foremost study introduces the long non-coding RNA PARTICLE into the context of human GBM pathogenesis while substantiating the role of GAS5 as a tumor suppressor. The validation of GBM biomarkers from cellular models contributes to the advancement towards superior detection, therapeutic responders and the ultimate attainment of promising prognoses for this currently incurable brain cancer.

Autophagy in combination therapy of temozolomide and IFN-γ in C6-induced glioblastoma: role of non-coding RNAs

Aim: We predicted the modulation of autophagy and apoptosis in response to temozolomide (TMZ) and IFN-γ based on changes in the expression of non-coding RNAs in C6-induced glioblastoma (GBM). Materials & methods: Each rat received an intraperitoneal injection of TMZ (7.5 mg/kg) and/or IFN-γ (50,000 IU). Results: The reduced expression of H19 and colorectal neoplasia differentially expressed (CRNDE) was associated with a reduction in autophagy in response to TMZ, IFN-γ and TMZ + IFN-γ therapy, whereas the decreased level of miR-29a (proapoptotic miRNA) was associated with an increase in apoptosis. Conclusion: It appears that H19 promotes switching from autophagy to apoptosis in response to combination therapy of TMZ and IFN-γ through the miR-29a/autophagy-related protein 9A (ATG9A) pathway in C6-induced GBM.

Role of Non-Coding RNAs in TGF-β Signalling in Glioma

Brain tumours and Gliomas, in particular, are among the primary causes of cancer mortality worldwide. Glioma diagnosis and therapy have not significantly improved despite decades of efforts. Autocrine TGF-β signalling promotes glioma proliferation, invasion, epithelial-to-mesenchymal transition (EMT), and drug resistance. Non-coding RNAs such as miRNA, lncRNA, and circRNAs have emerged as critical transcriptional and post-transcriptional regulators of TGF-β pathway components in glioma. Here, we summarize the complex regulatory network among regulatory ncRNAs and TGF-β pathway during Glioma pathogenesis and discuss their role as potential therapeutic targets for Gliomas.

LncRNA CASC2 Inhibits Progression of Glioblastoma by Regulating the Expression of AKT in T98G Cell Line, Treated by TMZ and Thiosemicarbazone Complex

BACKGROUND

The aim of this study was to evaluate the expression alterations of CACS2 and its target gene, AKT, in T98G cell line treated with Temozolomide and Thiosemicarbazone complex (Ni, Cu) and to compare the results with each other.

METHODS

Temozolomide and Thiosemicarbazone complexes were prepared in different concentrations. Cell culturing of T98G cell line was carried out and was classified into 3 groups based on the incubation time (24, 48, and 72h) with utilized agents, after RNA extraction the expression level of CACS2 and AKT genes were evaluated by Real-time PCR. Ultimately, the results were analyzed by Rest software.

RESULTS

CASC2 expression under Temozolomide treatment at different concentrations (100, 150, 200, and 250 µM) and different time periods (24, 48, and 72h) was increased. Moreover, its expression was significantly upregulated after treating with Ni at the concentrations of 100.5 and 104 µM after 24h. Furthermore, its expression was augmented after 72 h Cu treatment at the concentrations of 15, 16, 17, and 18 µM. In addition, AKT expression after Temozolomide and Thiosemicarbazone complex treatment was significantly decreased (P <0.001). The results showed that the expression alterations of CASC2 and its target gene, AKT, after treatment with Temozolomide and Thiosemicarbazone are highly depended on incubation time and concentration.

CONCLUSION

In a conclusion, the studied agents at different concentrations and times showed a high potential to control the expression of the studied lncRNA and gene in glioblastoma cells.

An overview of glioblastoma multiforme and temozolomide resistance: can LC-MS-based proteomics reveal the fundamental mechanism of temozolomide resistance?

Glioblastoma multiforme (GBM) is a primary type of lethal brain tumor. Over the last two decades, temozolomide (TMZ) has remained the primary chemotherapy for GBM. However, TMZ resistance in GBM constitutes an underlying factor contributing to high rates of mortality. Despite intense efforts to understand the mechanisms of therapeutic resistance, there is currently a poor understanding of the molecular processes of drug resistance. For TMZ, several mechanisms linked to therapeutic resistance have been proposed. In the past decade, significant progress in the field of mass spectrometry-based proteomics has been made. This review article discusses the molecular drivers of GBM, within the context of TMZ resistance with a particular emphasis on the potential benefits and insights of using global proteomic techniques.

Crosstalk between SOX Genes and Long Non-Coding RNAs in Glioblastoma

Glioblastoma (GBM) continues to be the most devastating primary brain malignancy. Despite significant advancements in understanding basic GBM biology and enormous efforts in developing new therapeutic approaches, the prognosis for most GBM patients remains poor with a median survival time of 15 months. Recently, the interplay between the SOX (SRY-related HMG-box) genes and lncRNAs (long non-coding RNAs) has become the focus of GBM research. Both classes of molecules have an aberrant expression in GBM and play essential roles in tumor initiation, progression, therapy resistance, and recurrence. In GBM, SOX and lncRNAs crosstalk through numerous functional axes, some of which are part of the complex transcriptional and epigenetic regulatory mechanisms. This review provides a systematic summary of current literature data on the complex interplay between SOX genes and lncRNAs and represents an effort to underscore the effects of SOX/lncRNA crosstalk on the malignant properties of GBM cells. Furthermore, we highlight the significance of this crosstalk in searching for new biomarkers and therapeutic approaches in GBM treatment.

Roles of circular RNAs in regulating the development of glioma

BACKGROUND

Glioma is the most common malignant tumor in the central nervous system. In patients with glioma, the prognosis is poor and median survival is only 12-15 months. With the recent development of sequencing technology, important roles of noncoding RNAs are being discovered in cells, especially those of circular RNAs (circRNAs). Because circRNAs are stable, abundant, and highly conserved, they are regarded as novel biomarkers in the early diagnosis and prognosis of diseases.

PURPOSE

In this review, roles and mechanisms of circRNAs in the development of glioma are summarized.

METHODS

This paper collects and reviews relevant PubMed literature.

CONCLUSION

Several classes of circRNAs are highly expressed in glioma and are associated with malignant biological behaviors of gliomas, including proliferation, migration, invasion, apoptosis, angiogenesis, and drug resistance. Further studies are needed to clarify the roles of circRNAs in glioma and to determine whether it is possible to increase therapeutic effects on tumors through circRNA intervention.

LncRNA PANTR1 is Associated with Poor Prognostic and Suppresses Apoptosis in Glioma

Glioma is the most common tumor in the central nervous system. High-grade gliomas confer a poor prognosis, being a serious health and economic burden. Current literature suggests the important role of long noncoding RNA (lncRNA) in mammals, especially in tumorigenesis of various tumors. The functions of lncRNA POU3F3 adjacent noncoding transcript 1 (PANTR1) have been investigated in hepatocellular carcinoma but remain yet unclear in gliomas. We evaluated the role of PANTR1 in glioma cells using published data from The Cancer Genome Atlas (TCGA), then validated it by ex vivo experiments. To investigate the potential cellular mechanism of different levels of PANTR1 expression in glioma cells, we used siRNA-mediated knockdown in low-grade (grade II) cell lines and GBM (grade IV) cell lines (SW1088 and SHG44, respectively). On the molecular level, low expression of PANTR1 caused significantly reduced glioma cell viability and enhanced cell death. Moreover, we identified the importance of PANTR1 expression for cell migration in both cell lines, a critical foundation for invasiveness in recurrent gliomas. In conclusion, this study provides the first evidence that PANTR1 has a relevant role in human glioma by influencing cell viability and cell death.

Novel tumor necrosis factor-related long non-coding RNAs signature for risk stratification and prognosis in glioblastoma

Background

Tumor necrosis factor (TNF) is an inflammatory cytokine that can coordinate tissue homeostasis by co-regulating the production of cytokines, cell survival, or death. It widely expresses in various tumor tissues and correlates with the malignant clinical features of patients. As an important inflammatory factor, the role of TNFα is involved in all steps of tumorigenesis and development, including cell transformation, survival, proliferation, invasion and metastasis. Recent research has showed that long non-coding RNAs (lncRNAs), defined as RNA transcripts >200 nucleotides that do not encode a protein, influence numerous cellular processes. However, little is known about the genomic profile of TNF pathway related-lncRNAs in GBM. This study investigated the molecular mechanism of TNF related-lncRNAs and their immune characteristics in glioblastoma multiforme (GBM) patients.

Methods

To identify TNF associations in GBM patients, we performed bioinformatics analysis of public databases - The Cancer Genome Atlas (TCGA) and the Chinese Glioma Genome Atlas (CGGA). The ConsensusClusterPlus, CIBERSORT, Estimate, GSVA and TIDE and first-order bias correlation and so on approaches were conducted to comprehensively characterize and compare differences among TNF-related subtypes.

Results

Based on the comprehensive analysis of TNF-related lncRNAs expression profiles, we constructed six TNF-related lncRNAs (C1RL-AS1, LINC00968, MIR155HG, CPB2-AS1, LINC00906, and WDR11-AS1) risk signature to determine the role of TNF-related lncRNAs in GBM. This signature could divide GBM patients into subtypes with distinct clinical and immune characteristics and prognoses. We identified three molecular subtypes (C1, C2, and C3), with C2 showing the best prognosis; otherwise, C3 showing the worst prognosis. Moreover, we assessed the prognostic value, immune infiltration, immune checkpoints, chemokines cytokines and enrichment analysis of this signature in GBM. The TNF-related lncRNA signature was tightly associated with the regulation of tumor immune therapy and could serve as an independent prognostic biomarker in GBM.

Conclusion

This analysis provides a comprehensive understanding of the role of TNF-related characters, which may improve the clinical outcome of GBM patients.

Emerging role of extracellular vesicles in the pathogenesis of glioblastoma

While brain tumors are not extremely frequent, they cause high mortality due to lack of appropriate treatment and late detection. Glioblastoma is the most frequent type of primary brain tumor. This malignant tumor has a highly aggressive behavior. Expression profile of different types of transcripts, methylation status of a number of genomic loci and chromosomal aberrations have been found to affect course of glioblastoma and propensity for recurrence and metastasis. Recent studies have shown that glioblastoma cells produce extracellular vesicles whose cargo can affect behavior of neighboring cells. Several miRNAs such as miR-301a, miR-221, miR-21, miR-16, miR-19b, miR-20, miR-26a, miR-92, miR-93, miR-29a, miR-222, miR-221 and miR-30a have been shown to be transferred by glioblastoma-derived extracellular vesicles and enhance the malignant behavior of these cells. Other components of glioblastoma-derived extracellular vesicles are EGFRvIII mRNA/protein, Ndfip1, PTEN, MYC ssDNA and IDH1 mRNA. In the current review, we discuss the available data about the molecular composition of glioblastoma-derived extracellular vesicles and their impact on the progression of this malignant tumor and its resistance to therapeutic modalities.

LINC01711 promotes transforming growth factor-beta (TGF-β) induced invasion in glioblastoma multiforme (GBM) by acting as a competing endogenous RNA for miR-34a and promoting ZEB1 expression

GBM is the central nervous system's most aggressive and malignant tumor. TGF-β expression is elevated in GBM, and it promotes invasion and EMT. TGF-β regulates the expression of several lncRNAs, which promote glioma pathogenesis. Here we characterize the role of TGF-β-induced lncRNA- LINC01711 in glioma pathogenesis. We show that LINC01711 expression is significantly upregulated in GBM tissues and is associated with poor overall survival of GBM patients. Loss-of-function studies illustrate that LINC01711 promotes proliferation, migration, and invasion in GBM. In addition, LINC01711 depletion sensitizes glioma cells to Temozolomide (TMZ) induced apoptosis by inhibiting ZEB1 expression. LINC01711 functions as a competing endogenous RNA for miR-34a and promotes ZEB1 expression to regulate invasion. Our findings suggest that LINC01711 is an attractive therapeutic target for GBM.

The evaluation expression of non-coding RNAs in response to HSV-G47∆ oncolytic virus infection in glioblastoma multiforme cancer stem cells

Glioblastoma multiforme is the most aggressive astrocytes brain tumor. Glioblastoma cancer stem cells and hypoxia conditions are well-known major obstacles in treatment. Studies have revealed that non-coding RNAs serve a critical role in glioblastoma progression, invasion, and resistance to chemo-radiotherapy. The present study examined the expression levels of microRNAs (in normoxic condition) and long non-coding RNAs (in normoxic and hypoxic conditions) in glioblastoma stem cells treated with the HSV-G47∆. The expression levels of 43 miRNAs and 8 lncRNAs isolated from U251-GBM-CSCs were analyzed using a miRCURY LNA custom PCR array and a quantitative PCR assay, respectively. The data revealed that out of 43 miRNAs that only were checked in normoxic condition, the only 8 miRNAs, including miR-7-1, miR-let-7b, miR-130a, miR-137, miR-200b, miR-221, miR-222, and miR-874, were markedly upregulated. The expression levels of lncRNAs, including LEF1 antisense RNA 1 (LEF1-AS1), metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), long intergenic non-protein coding RNA 470 (LINC00470), tumor suppressor candidate 7 (TUSC7), HOX transcript antisense RNA (HOTAIR), nuclear paraspeckle assembly transcript 1 (NEAT1), and X inactive specific transcript (XIST), were markedly downregulated in the hypoxic microenvironment, and H19-imprinted maternally expressed transcript (H19) was not observed to be dysregulated in this environment. Under normoxic conditions, LEF1-AS1, MALAT1, LINC00470, H19, HOTAIR, NEAT1, and XIST were downregulated and TUSC7 was not targeted by HSV-G47∆. Overall, the present data shows HSVG47Δ treatment deregulates non-coding RNA expression in GBM-CSC tumor microenvironments.

Profiling and Bioinformatics Analyses of Differential Circular RNA Expression in Glioblastoma Multiforme Cells Under Hypoxia

The hypoxia microenvironment is highly associated with GBM's malignant phenotypes. CircRNAs were reported involved in GBM's biological characteristics and regulated by HIF-1α. However, the differential expression profile and role of circRNAs in GBM cells under hypoxia are still unclear. The expression profiles of circRNAs in LN229 and T98G under hypoxia were explored via circRNA sequencing analysis. Those circRNAs significantly dysregulated both in LN229 and T98G and could be found in circBase were selected and validated by qRT-PCR, RNase R digestion reaction, and Sanger sequencing. Normal cell line and fresh GBM tissues were also used for qRT-PCR validation. The roles of differentially expressed circRNAs were evaluated by bioinformatics analyses. There were 672 dysregulated circRNAs in LN229 and 698 dysregulated circRNAs in T98G. GO analysis indicated that the alteration of circRNA expression related to GBM cell's biogenesis and metabolism. KEGG analysis demonstrated that TGF-β signaling pathway, HIF-1 signaling pathway, and metabolism-related signaling pathway were closely associated with differentially expressed circRNAs under hypoxia. These results were confirmed by GSEA analysis. The 6 selected and dysregulated circRNAs both in LN229 and T98G including hsa_circ_0000745, hsa_circ_0020093, hsa_circ_0020094, hsa_circ_0000943, hsa_circ_0004874, and hsa_circ_0002359 were validated by qRT-PCR. Inhibition of hsa_circ_0000745 inhibited GBM cell's proliferation, migration, and invasion. HIF-1α centered circRNA-miRNA-mRNA networks analysis showed that the 6 validated circRNAs could cross-talk with 11 related miRNAs. The circRNA expressions are dysregulated in GBM cell under hypoxia. The 6 validated circRNAs could participate in GBM's development and progression when hypoxia occurs. They might be the candidates for prognostic markers and adjuvant therapeutics of GBM in the future.

The role of the ZEB1–neuroinflammation axis in CNS disorders

Zinc finger E-box binding homeobox 1 (ZEB1) is a master modulator of the epithelial–mesenchymal transition (EMT), a process whereby epithelial cells undergo a series of molecular changes and express certain characteristics of mesenchymal cells. ZEB1, in association with other EMT transcription factors, promotes neuroinflammation through changes in the production of inflammatory mediators, the morphology and function of immune cells, and multiple signaling pathways that mediate the inflammatory response. The ZEB1–neuroinflammation axis plays a pivotal role in the pathogenesis of different CNS disorders, such as brain tumors, multiple sclerosis, cerebrovascular diseases, and neuropathic pain, by promoting tumor cell proliferation and invasiveness, formation of the hostile inflammatory micromilieu surrounding neuronal tissues, dysfunction of microglia and astrocytes, impairment of angiogenesis, and dysfunction of the blood–brain barrier. Future studies are needed to elucidate whether the ZEB1–neuroinflammation axis could serve as a diagnostic, prognostic, and/or therapeutic target for CNS disorders.

In silico characterization of competing endogenous RNA network in glioblastoma multiforme with a systems biology approach

Glioblastoma multiforme (GBM) is the most frequent malignant type of primary brain cancers and is a malignancy with poor prognosis. Thus, it is necessary to find novel therapeutic modalities based on molecular events occur at different stages of tumor progression. We used expression profiles of GBM tissues that contained long non-coding RNA (lncRNA), microRNA (miRNA) and mRNA signatures to make putative ceRNA networks. Our strategy led to identification of 1080 DEmRNAs, including 777 downregulated DEmRNAs (such as GJB6 and SLC12A5) and 303 upregulated DEmRNAs (such as TOP2A and RRM2), 19 DElncRNAs, including 16 downregulated DElncRNAs (such as MIR7-3HG and MIR124-2HG) and 3 upregulated DElncRNAs (such as CRNDE and XIST) and 49 DEmiRNAs, including 10 downregulated DEmiRNAs (such as hsa-miR-10b-5p and hsa-miR-1290) and 39 upregulated DEmiRNAs (such as hsa-miR-219a-2-3p and hsa-miR-338-5p). We also identified DGCR5, MIAT, hsa-miR-129-5p, XIST, hsa-miR-128-3p, PART1, hsa-miR-10b-5p, LY86-AS1, CRNDE, and DLX6-AS1 as 10 hub genes in the ceRNA network. The current study provides novel insight into molecular events during GBM pathogenesis. The identified molecules can be used as therapeutic targets for GBM.

Regulation of temozolomide resistance via lncRNAs: Clinical and biological properties of lncRNAs in gliomas (Review)

Gliomas are a primary types of intracranial malignancies and are characterized by a poor prognosis due to aggressive recurrence profiles. Temozolomide (TMZ) is an auxiliary alkylating agent that is extensively used in conjunction with surgical resection and forms the mainstay of clinical treatment strategies for gliomas. However, the frequent occurrence of TMZ resistance in clinical practice limits its therapeutic efficacy. Accumulating evidence has demonstrated that long non‑coding RNAs (lncRNAs) can play key and varied roles in glioma progression. lncRNAs have been reported to inhibit glioma progression by targeting various signaling pathways. In addition, the differential expression of lncRNAs has also been found to mediate the resistance of glioma to several chemotherapeutic agents, particularly to TMZ. The present review article therefore summarizes the findings of previous studies in an aim to report the significance and function of lncRNAs in regulating the chemoresistance of gliomas. The present review may provide further insight into the clinical treatment of gliomas.

Prognostic utility of lncRNAs (LINC00565 and LINC00641) as molecular markers in glioblastoma multiforme (GBM)

Background and aim

Glioblastoma multiforme (GBM) is primary brain tumor grade IV characterized by fast cell proliferation, high mortality and morbidity and most lethal gliomas. Molecular approaches underlying its pathogenesis and progression with diagnostic and prognostic value have been an area of interest. Long-non coding RNAs (lncRNAs) aberrantly expressed in GBM have been recently studied. The aim is to investigate the clinical role of lncRNA565 and lncRNA641 in GBM patients.

Patients and methods

Blood samples were withdrawn from 35 newly diagnosed GBM cases with 15 healthy individuals, then lncRNA565 and lncRNA641 expression were evaluated using real time-PCR. Their diagnostic efficacy was detected using receiver operating characteristic curve. Progression free survival (PFS) and overall survival (OS) were studied using Kaplan–Meier curves.

Results

lncRNAs expressions were increased significantly among GBM as compared to control group. Their expressions were correlated with clinico-pathological data and survival pattern for the studied GBM patients. Higher levels of both lncRNAs were correlated to worse performance status. Expression of lncRNA565 was increased with large tumor size (≥ 5 cm). Survival analysis showed that both investigated lncRNA were increased with worse PFS and OS.

Conclusion

Expression of lncRNA565 and lncRNA641 in a liquid biopsy sample can be used as prognostic biomarker for GBM patients.

Alterations in Molecular Profiles Affecting Glioblastoma Resistance to Radiochemotherapy: Where Does the Good Go?

Simple Summary

Glioblastoma is a type of brain cancer that remains incurable. Despite multiple past and ongoing preclinical studies and clinical trials, involving adjuvants to the conventional therapy and based on molecular targeting, no relevant benefit for patients’ survival has been achieved so far. The current first-line treatment regimen is based on ionizing radiation and the monoalkylating compound, temozolomide, and has been administered for more than 15 years. Glioblastoma is extremely resistant to most agents due to a mutational background that elicits quick response to insults and adapts to microenvironmental and metabolic changes. Here, we present the most recent evidence concerning the molecular features and their alterations governing pathways involved in GBM response to the standard radio-chemotherapy and discuss how they collaborate with acquired GBM’s resistance.

Abstract

Glioblastoma multiforme (GBM) is a brain tumor characterized by high heterogeneity, diffuse infiltration, aggressiveness, and formation of recurrences. Patients with this kind of tumor suffer from cognitive, emotional, and behavioral problems, beyond exhibiting dismal survival rates. Current treatment comprises surgery, radiotherapy, and chemotherapy with the methylating agent, temozolomide (TMZ). GBMs harbor intrinsic mutations involving major pathways that elicit the cells to evade cell death, adapt to the genotoxic stress, and regrow. Ionizing radiation and TMZ induce, for the most part, DNA damage repair, autophagy, stemness, and senescence, whereas only a small fraction of GBM cells undergoes treatment-induced apoptosis. Particularly upon TMZ exposure, most of the GBM cells undergo cellular senescence. Increased DNA repair attenuates the agent-induced cytotoxicity; autophagy functions as a pro-survival mechanism, protecting the cells from damage and facilitating the cells to have energy to grow. Stemness grants the cells capacity to repopulate the tumor, and senescence triggers an inflammatory microenvironment favorable to transformation. Here, we highlight this mutational background and its interference with the response to the standard radiochemotherapy. We discuss the most relevant and recent evidence obtained from the studies revealing the molecular mechanisms that lead these cells to be resistant and indicate some future perspectives on combating this incurable tumor.

Emerging Concepts on the Role of Extracellular Vesicles and Its Cargo Contents in Glioblastoma-Microglial Crosstalk

Glioblastoma multiforme is the most common, highly aggressive malignant brain tumor which is marked by highest inter- and intra-tumoral heterogeneity. Despite, immunotherapy, and combination therapies developed; the clinical trials often result into large number of failures. Often cancer cells are known to communicate with surrounding cells in tumor microenvironment (TME). Extracellular vesicles (EVs) consisting of diverse cargo mediates this intercellular communication and is believed to modulate the immune function against GBM. Tumor-associated microglia (TAM), though being the resident innate immune cell of CNS, is known to attain pro-tumorigenic M2 phenotype, and this immunomodulation is aided by extracellular vesicle-mediated transfer of oncogenic, immunomodulatory molecules. Besides, oncogenic proteins, long non-coding RNAs (lncRNAs), are believed to carry oncogenic potential, and therefore, understanding the mechanism leading to microglial dysregulation mediated by GBM-derived extracellular vesicle (GDEV) lncRNAs becomes crucial. This review focuses on current understanding of role of GDEV and lncRNA in microglial dysfunction and its potential as a therapeutic target.

LncRNA SBF2-AS1: A Budding Star in Various Cancers

Long non-coding RNA (lncRNA) is a new kind of RNA with lengths over 200 nucleotides. Current frontiers revealed that lncRNAs implicate in various tumor progression, including tumorigenesis, proliferation, migration, invasion, metastasis and angiogenesis. Recently discovered long non-coding RNA SET-binding factor 2 antisense RNA 1 (lncRNA SBF2-AS1), an oncogenic antisense RNA to SBF2, locates at 11p15.1 locus and is 2708 nt long. Accumulating evidences have demonstrated that lncRNA SBF2-AS1 participates in various tumor progression including pathogenesis, diagnosis, treatment and prognosis of acute myeloid leukemia (AML), breast cancer (BC), cervical cancer (CC), clear cell renal cell carcinoma (ccRCC), colorectal cancer (CRC), diffuse large B-cell lymphoma (DLBCL), esophageal squamous cell carcinoma (ESCC), gastric cancer (GC), glioma, glioblastoma (GBM), hepatocellular carcinoma (HCC), lung cancer (LC), lung adenocarcinoma (LUAD), non-small cell lung cancer (NSCLC), osteosarcoma (OS), pancreatic cancer (PC), papillary thyroid cancer (PTC), small cell lung cancer (SCLC). Therefore, we summarized the underlying mechanisms about lncRNA SBF2-AS1 in various cancers to utilize its therapeutic function in target-selective treatment modality.

Transforming Growth Factor-Beta-Regulated LncRNA-MUF Promotes Invasion by Modulating the miR-34a Snail1 Axis in Glioblastoma Multiforme

Transforming growth factor beta (TGF-β)-regulated long-non-coding RNAs (lncRNAs) modulate several aspects of tumor development such as proliferation, invasion, metastasis, epithelial to mesenchymal transition (EMT), and drug resistance in various cancers, including Glioblastoma multiforme (GBM). We identified several novel differentially expressed lncRNAs upon TGF-β treatment in glioma cells using genome-wide microarray screening. We show that TGF-β induces lncRNA-MUF in glioma cells, and its expression is significantly upregulated in glioma tissues and is associated with poor overall survival of GBM patients. Knockdown of lncRNA-MUF reduces proliferation, migration, and invasion in glioma cells and sensitizes them to temozolomide (TMZ)-induced apoptosis. In addition, lncRNA-MUF downregulation impairs TGF-β-induced smad2/3 phosphorylation. In line with its role in regulating invasion, lncRNA-MUF functions as a competing endogenous RNA (ceRNA) for miR-34a and promotes Snail1 expression. Collectively, our findings suggest lncRNA-MUF as an attractive therapeutic target for GBM.

Mechanisms of Long Non-Coding RNAs in Biological Characteristics and Aerobic Glycolysis of Glioma

Glioma is the most common and aggressive tumor of the central nervous system. The uncontrolled proliferation, cellular heterogeneity, and diffusive capacity of glioma cells contribute to a very poor prognosis of patients with high grade glioma. Compared to normal cells, cancer cells exhibit a higher rate of glucose uptake, which is accompanied with the metabolic switch from oxidative phosphorylation to aerobic glycolysis. The metabolic reprogramming of cancer cell supports excessive cell proliferation, which are frequently mediated by the activation of oncogenes or the perturbations of tumor suppressor genes. Recently, a growing body of evidence has started to reveal that long noncoding RNAs (lncRNAs) are implicated in a wide spectrum of biological processes in glioma, including malignant phenotypes and aerobic glycolysis. However, the mechanisms of diverse lncRNAs in the initiation and progression of gliomas remain to be fully unveiled. In this review, we summarized the diverse roles of lncRNAs in shaping the biological features and aerobic glycolysis of glioma. The thorough understanding of lncRNAs in glioma biology provides opportunities for developing diagnostic biomarkers and novel therapeutic strategies targeting gliomas.

Roles of ncRNAs as ceRNAs in Gastric Cancer

Although ignored in the past, with the recent deepening of research, significant progress has been made in the field of non-coding RNAs (ncRNAs). Accumulating evidence has revealed that microRNA (miRNA) response elements regulate RNA. Long ncRNAs, circular RNAs, pseudogenes, miRNAs, and messenger RNAs (mRNAs) form a competitive endogenous RNA (ceRNA) network that plays an essential role in cancer and cardiovascular, neurodegenerative, and autoimmune diseases. Gastric cancer (GC) is one of the most common cancers, with a high degree of malignancy. Considerable progress has been made in understanding the molecular mechanism and treatment of GC, but GC’s mortality rate is still high. Studies have shown a complex ceRNA crosstalk mechanism in GC. lncRNAs, circRNAs, and pseudogenes can interact with miRNAs to affect mRNA transcription. The study of the involvement of ceRNA in GC could improve our understanding of GC and lead to the identification of potential effective therapeutic targets. The research strategy for ceRNA is mainly to screen the different miRNAs, lncRNAs, circRNAs, pseudogenes, and mRNAs in each sample through microarray or sequencing technology, predict the ceRNA regulatory network, and, finally, conduct functional research on ceRNA. In this review, we briefly discuss the proposal and development of the ceRNA hypothesis and the biological function and principle of ceRNAs in GC, and briefly introduce the role of ncRNAs in the GC’s ceRNA network.

Role of Long Non-Coding RNAs in Conferring Resistance in Tumors of the Nervous System

Tumors of the nervous system can be originated from several locations. They mostly have high mortality and morbidity rate. The emergence of resistance to chemotherapeutic agents is a hurdle in the treatment of patients. Long non-coding RNAs (lncRNAs) have been shown to influence the response of glioblastoma/glioma and neuroblastoma to chemotherapeutic agents. MALAT1, NEAT1, and H19 are among lncRNAs that affect the response of glioma/glioblastoma to chemotherapy. As well as that, NORAD, SNHG7, and SNHG16 have been shown to be involved in conferring this phenotype in neuroblastoma. Prior identification of expression amounts of certain lncRNAs would help in the better design of therapeutic regimens. In the current manuscript, we summarize the impact of lncRNAs on chemoresistance in glioma/glioblastoma and neuroblastoma.

In vivo Engineering of Chromosome 19 q-arm by Employing the CRISPR/AsCpf1 and ddAsCpf1 Systems in Human Malignant Gliomas (Hypothesis)

Deletions of the q13.3 region of chromosome 19 have been found commonly in all three main kinds of diffuse human malignant gliomas, powerfully demonstrating the existence of tumor suppressor genes in this region. Consistent with the previous studies, the most common deletion interval has been mapped to a roughly 4 Mb region of 19q13.3 between the APOC2 and HRC genes, between genetic markers D19S219 and D19S246. EML2 is a tumor suppressor gene that is located on 19q13.32 and is considerably methylated in high-grade gliomas. Notably, MIR330 gene that is situated within the non-coding intronic region of EML2 is also detected as an oncosuppressor-miR in a variety of cancers including gliomas. Additionally, glioma oncoprotein Bcl2L12 which is located on 19q13.33 is significantly overexpressed in glioblastoma multiform and has a pivotal role in cancer evolution and resistance to apoptosis. Other genes such as MIR519D and NOP53 are also discovered as tumor suppressor genes in gliomas which are located on 19q13.3 and 19q13.4, respectively. Therefore, we hypothesize that a CRISPR/AsCpf1-based genome engineering strategy might be utilized to attach these deleted sizeable chromosomal portions of genes coding tumor suppressors as vital parts of the chromosome 19 q-arm with the purpose of treatment of this chromosomal abnormality in gliomas. Also, we can concurrently employ the CRISPR-ddAsCpf1 strategy for the precise suppression of Bcl2L12 oncogene in glioma.