Coding of Glioblastoma Progression and Therapy Resistance through Long Noncoding RNAs

Innovative perspectives on glioblastoma: the emerging role of long non-coding RNAs

Glioblastoma (GBM) is a highly aggressive and treatment-resistant brain tumor. Recent advancements have highlighted the crucial role of long noncoding RNAs (lncRNAs) in GBM's molecular biology. Unlike protein-coding RNAs, lncRNAs regulate gene expression through transcription, post-transcriptional modifications, and chromatin remodeling. Some lncRNAs, like HOTAIR, CCAT2, CRNDE, and MALAT1, promote GBM development by affecting tumor suppressors and various signaling pathways like PI3K/Akt, mTOR, EGFR, NF-κB, and Wnt/β-catenin. Conversely, certain lncRNAs such as TUG1, MEG3, and GAS8-AS1 act as tumor suppressors and are associated with better prognosis. The study presented in the manuscript aims to explore the involvement of lncRNAs in GBM, focusing on their roles in tumor progression, proliferation, invasion, and potential implications for early detection and immunotherapy. The research seeks to elucidate the mechanisms by which specific lncRNAs influence GBM characteristics and highlight their potential as therapeutic targets or biomarkers in managing this aggressive form of brain cancer.

New sights on long non-coding RNAs in glioblastoma: A review of molecular mechanism

Glioma or glioblastoma (GBM) is one of the aggressive and fatal primary cerebral malignancies, with the highest mortality rate among all brain-related tumors. Also, glioma mainly progresses as a more invasive phenotype after primary treatment. Cumulative evidence suggested that dysregulation of noncoding RNAs (ncRNAs) such as long non-coding RNAs (LncRNAs) and microRNAs (miRNAs) are associated with tumor initiation, progression, and drug resistance, through epigenetic modifications, transcriptional, and post-transcriptional processes in the cells. Many scientific investigations have revealed that LncRNAs play important roles in various biological procedures linked with the development and progression of GBM. In recent years, it has been shown that dysregulation of molecular mechanisms in many LncRNAs such as MIR22HG, HULC, AGAP2-AS1, MALAT1, PVT1, TTTY14, HOTAIRM1, PTAR, LPP-AS2, LINC00336, and TINCR are connected with the GBM. Therefore, this scientific review paper focused on the molecular mechanisms of these LncRNAs in the context of GBM.

Shedding light on function of long non-coding RNAs (lncRNAs) in glioblastoma

The brain tumors and especially glioblastoma, are affecting life of many people worldwide and due to their high mortality and morbidity, their treatment is of importance and has gained attention in recent years. The abnormal expression of genes is commonly observed in GBM and long non-coding RNAs (lncRNAs) have demonstrated dysregulation in this tumor. LncRNAs have length more than 200 nucleotides and they have been located in cytoplasm and nucleus. The current review focuses on the role of lncRNAs in GBM. There two types of lncRNAs in GBM including tumor-promoting and tumor-suppressor lncRNAs and overexpression of oncogenic lncRNAs increases progression of GBM. LncRNAs can regulate proliferation, cell cycle arrest and metastasis of GBM cells. Wnt, STAT3 and EZH2 are among the molecular pathways affected by lncRNAs in GBM and for regulating metastasis of GBM cells, these RNA molecules mainly affect EMT mechanism. LncRNAs are involved in drug resistance and can induce resistance of GBM cells to temozolomide chemotherapy. Furthermore, lncRNAs stimulate radio-resistance in GBM cells. LncRNAs increase PD-1 expression to mediate immune evasion. LncRNAs can be considered as diagnostic and prognostic tools in GBM and researchers have developed signature from lncRNAs in GBM.

Exploring ncRNA-mediated regulation of EGFR signalling in glioblastoma: From mechanisms to therapeutics

Glioblastoma (GBM) is the most prevalent and deadly primary brain tumor type, with a discouragingly low survival rate and few effective treatments. An important function of the EGFR signalling pathway in the development of GBM is to affect tumor proliferation, persistence, and treatment resistance. Advances in molecular biology in the last several years have shown how important ncRNAs are for controlling a wide range of biological activities, including cancer progression and development. NcRNAs have become important post-transcriptional regulators of gene expression, and they may affect the EGFR pathway by either directly targeting EGFR or by modifying important transcription factors and downstream signalling molecules. The EGFR pathway is aberrantly activated in response to the dysregulation of certain ncRNAs, which has been linked to GBM carcinogenesis, treatment resistance, and unfavourable patient outcomes. We review the literature on miRNAs, circRNAs and lncRNAs that are implicated in the regulation of EGFR signalling in GBM, discussing their mechanisms of action, interactions with the signalling pathway, and implications for GBM therapy. Furthermore, we explore the potential of ncRNA-based strategies to overcome resistance to EGFR-targeted therapies, including the use of ncRNA mimics or inhibitors to modulate the activity of key regulators within the pathway.

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.

Dysregulation of LINC00324 promotes poor prognosis in patients with glioma

BACKGROUND

LINC00324 is a long-stranded non-coding RNA, which is aberrantly expressed in various cancers and is associated with poor prognosis and clinical features. It involves multiple oncogenic molecular pathways affecting cell proliferation, migration, invasion, and apoptosis. However, the expression, function, and mechanism of LINC00324 in glioma have not been reported.

MATERIAL AND METHODS

We assessed the expression of LINC00324 of LINC00324 in glioma patients based on data from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) to identify pathways involved in LINC00324-related glioma pathogenesis.

RESULTS

Based on our findings, we observed differential expression of LINC00324 between tumor and normal tissues in glioma patients. Our analysis of overall survival (OS) and disease-specific survival (DSS) indicated that glioma patients with high LINC00324 expression had a poorer prognosis compared to those with low LINC00324 expression. By integrating clinical data and genetic signatures from TCGA patients, we developed a nomogram to predict OS and DSS in glioma patients. Gene set enrichment analysis (GSEA) revealed that several pathways, including JAK/STAT3 signaling, epithelial-mesenchymal transition, STAT5 signaling, NF-κB activation, and apoptosis, were differentially enriched in glioma samples with high LINC00324 expression. Furthermore, we observed significant correlations between LINC00324 expression, immune infiltration levels, and expression of immune checkpoint-related genes (HAVCR2: r = 0.627, P = 1.54e-77; CD40: r = 0.604, P = 1.36e-70; ITGB2: r = 0.612, P = 6.33e-7; CX3CL1: r = -0.307, P = 9.24e-17). These findings highlight the potential significance of LINC00324 in glioma progression and suggest avenues for further research and potential therapeutic targets.

CONCLUSION

Indeed, our results confirm that the LINC00324 signature holds promise as a prognostic predictor in glioma patients. This finding opens up new possibilities for understanding the disease and may offer valuable insights for the development of targeted therapies.

Glioblastoma Therapy: Past, Present and Future

Glioblastoma (GB) stands out as the most prevalent and lethal form of brain cancer. Although great efforts have been made by clinicians and researchers, no significant improvement in survival has been achieved since the Stupp protocol became the standard of care (SOC) in 2005. Despite multimodality treatments, recurrence is almost universal with survival rates under 2 years after diagnosis. Here, we discuss the recent progress in our understanding of GB pathophysiology, in particular, the importance of glioma stem cells (GSCs), the tumor microenvironment conditions, and epigenetic mechanisms involved in GB growth, aggressiveness and recurrence. The discussion on therapeutic strategies first covers the SOC treatment and targeted therapies that have been shown to interfere with different signaling pathways (pRB/CDK4/RB1/P16ink4, TP53/MDM2/P14arf, PI3k/Akt-PTEN, RAS/RAF/MEK, PARP) involved in GB tumorigenesis, pathophysiology, and treatment resistance acquisition. Below, we analyze several immunotherapeutic approaches (i.e., checkpoint inhibitors, vaccines, CAR-modified NK or T cells, oncolytic virotherapy) that have been used in an attempt to enhance the immune response against GB, and thereby avoid recidivism or increase survival of GB patients. Finally, we present treatment attempts made using nanotherapies (nanometric structures having active anti-GB agents such as antibodies, chemotherapeutic/anti-angiogenic drugs or sensitizers, radionuclides, and molecules that target GB cellular receptors or open the blood-brain barrier) and non-ionizing energies (laser interstitial thermal therapy, high/low intensity focused ultrasounds, photodynamic/sonodynamic therapies and electroporation). The aim of this review is to discuss the advances and limitations of the current therapies and to present novel approaches that are under development or following clinical trials.

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.

Nucleic Acids in Cancer Diagnosis and Therapy

Nucleic acids include two main classes: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) [...].

Nucleic acid drug vectors for diagnosis and treatment of brain diseases

Nucleic acid drugs have the advantages of rich target selection, simple in design, good and enduring effect. They have been demonstrated to have irreplaceable superiority in brain disease treatment, while vectors are a decisive factor in therapeutic efficacy. Strict physiological barriers, such as degradation and clearance in circulation, blood-brain barrier, cellular uptake, endosome/lysosome barriers, release, obstruct the delivery of nucleic acid drugs to the brain by the vectors. Nucleic acid drugs against a single target are inefficient in treating brain diseases of complex pathogenesis. Differences between individual patients lead to severe uncertainties in brain disease treatment with nucleic acid drugs. In this Review, we briefly summarize the classification of nucleic acid drugs. Next, we discuss physiological barriers during drug delivery and universal coping strategies and introduce the application methods of these universal strategies to nucleic acid drug vectors. Subsequently, we explore nucleic acid drug-based multidrug regimens for the combination treatment of brain diseases and the construction of the corresponding vectors. In the following, we address the feasibility of patient stratification and personalized therapy through diagnostic information from medical imaging and the manner of introducing contrast agents into vectors. Finally, we take a perspective on the future feasibility and remaining challenges of vector-based integrated diagnosis and gene therapy for brain diseases.

Meta-Analysis of RNA-Seq Datasets Identifies Novel Players in Glioblastoma

Glioblastoma is a devastating grade IV glioma with poor prognosis. Identification of predictive molecular biomarkers of disease progression would substantially contribute to better disease management. In the current study, we performed a meta-analysis of different RNA-seq datasets to identify differentially expressed protein-coding genes (PCGs) and long non-coding RNAs (lncRNAs). This meta-analysis aimed to improve power and reproducibility of the individual studies while identifying overlapping disease-relevant pathways. We supplemented the meta-analysis with small RNA-seq on glioblastoma tissue samples to provide an overall transcriptomic view of glioblastoma. Co-expression correlation of filtered differentially expressed PCGs and lncRNAs identified a functionally relevant sub-cluster containing DANCR and SNHG6, with two novel lncRNAs and two novel PCGs. Small RNA-seq of glioblastoma tissues identified five differentially expressed microRNAs of which three interacted with the functionally relevant sub-cluster. Pathway analysis of this sub-cluster identified several glioblastoma-linked pathways, which were also previously associated with the novel cell death pathway, ferroptosis. In conclusion, the current meta-analysis strengthens evidence of an overarching involvement of ferroptosis in glioblastoma pathogenesis and also suggests some candidates for further analyses.

Long non-coding RNA LINC01018 inhibits human glioma cell proliferation and metastasis by directly targeting miRNA-182-5p

AIM

Accumulating evidence suggests that lncRNAs are potential biomarkers and key regulators of tumor development and progression. However, the precise function of most lncRNAs in glioma remains unknown. In this study, we explored the role of long intergenic non-protein coding RNA 1018 (LINC01018) in human glioma.

METHODS

Expression levels of LINC01018 and miR-182-5p in clinical glioma tissues and cell lines were detected by quantitative real-time PCR (qRT-PCR). Cell proliferation, migration, and invasion were determined by Cell Counting Kit-8 (CCK-8) assay and Transwell assay. Epithelial-mesenchymal transition (EMT) related proteins were measured by Western blotting. Direct relationship between LINC01018 and miR-182-5p was tested by dual-luciferase reporter assay, RNA immunoprecipitation assay (RIP), and rescue assays. Lastly, bioinformatics analyses were conducted to predict the downstream factors of LINC01018/miR-182-5p axis in glioma.

RESULTS

LINC01018 was significantly down-regulated in glioma tissues and cell lines. Overexpression of LINC01018 dramatically inhibited cell proliferation, migration, and invasion and reverse EMT process in glioma. LINC01018 directly target to miR-182-5p. Forced up-regulation of miR-182-5p reversed the inhibitory effects on proliferative and metastatic abilities of glioma cells with LINC01018 overexpression. Lastly, the bioinformatics analyses revealed that LINC01018/miR-182-5p axis mediated a cluster of downstream genes (ADRA2C, RAB6B, RAB27B, RAPGEF5, STEAP2, TAGLN3, and UNC13C), which were potential key factors in the development of glioma.

CONCLUSION

LINC01018 inhibits cell proliferation and metastasis in human glioma by targeting miR-182-5p, and should be considered as a potential therapeutic target in this cancer.

MIR99AHG/miR-204-5p/TXNIP/Nrf2/ARE Signaling Pathway Decreases Glioblastoma Temozolomide Sensitivity

Glioblastoma (GBM) is the most prevalent primary cerebral tumor in adults with high aggressiveness. Temozolomide (TMZ) is considered as the most widely used chemotherapy for GBM patients. Accumulating studies have proved that long non-coding RNAs (lncRNAs) participate in the pathogenesis of tumors. The aim of our study is to disclose the role of mir-99a-let-7c cluster host gene (MIR99AHG) in GBM. MIR99AHG expression was discovered to be elevated in GBM cells through quantitative real-time polymerase chain reaction (RT-qPCR) analysis. Loss-of-function experiments demonstrated that MIR99AHG silencing enhanced TMZ sensitivity of GBM both in vitro and in vivo. RNA pull down, RNA-binding protein immunoprecipitation (RIP), and luciferase reporter assays were implemented to unveil the underlying mechanism of MIR99AHG in GBM. The results of the mechanism assays implied that MIR99AHG interacted with microRNA-204-5p (miR-204-5p) and enhanced thioredoxin interacting protein (TXNIP) expression to inactivate the Nrf2/ARE signaling pathway. MIR99AHG/miR-204-5p/TXNIP regulatory axis was verified by rescue experiments in GBM. To summarize, MIR99AHG plays a promoting role in the TMZ resistance of GBM cells. The findings in this study might provide novel sight for the treatment for GBM.

Identifying Autophagy-Related lncRNAs and Potential ceRNA Networks in NAFLD

Nonalcoholic fatty liver disease (NAFLD) is a common chronic disease with complex pathogenesis, which brings economic burden to the society, and there is still no effective therapy. Impaired autophagy has been implicated in the development of NAFLD. Long noncoding RNAs (lncRNAs) are also reported to play a role in the pathogenesis of NAFLD. However, the role of autophagy-related lncRNAs in NAFLD disease has not been elucidated. Here, we mined GSE135251, GSE160016, GSE130970 and GSE185062 datasets from the Gene Expression Omnibus database (GEO) and obtained the human autophagy-related gene list from the Human Autophagy Database (HADb) for in-depth bioinformatic analysis. Following differential expression analysis and intersection of the datasets, Pearson correlation analysis was performed on DElncRNAs and autophagy-related DEmRNAs to obtain autophagy-related lncRNAs, and then Starbase3.0 and TargetScan7.2 were used to construct competing endogenous RNAs (ceRNA) regulatory networks. We constructed four lncRNA-dominated ceRNA regulatory networks (PSMG3-AS1, MIRLET7BHG, RP11-136K7.2, LINC00925), and visualized with Cytoscape. Then we performed co-expression analysis of the ceRNA networks and autophagy-related genes, and functionally annotated them with Metascape. Finally, we performed receiver operating characteristic curve (ROC) analysis on lncRNAs and mRNAs within the ceRNA networks. Conclusively, our project is the first to study autophagy-related lncRNAs in NAFLD and finally mined four autophagy-related lncRNAs (PSMG3-AS1, MIRLET7BHG, RP11-136K7.2, LINC00925). We suggested that the four autophagy-related lncRNAs may be closely associated with the occurrence and development of NAFLD through the corresponding ceRNA regulatory networks. This research brings new horizons to the study of NAFLD.

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

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

Dynamic Intercell Communication between Glioblastoma and Microenvironment through Extracellular Vesicles

Glioblastoma is simultaneously the most common and most aggressive primary brain tumor in the central nervous system, with poor patient survival and scarce treatment options. Most primary glioblastomas reoccur and evolve radio- and chemoresistant properties which make them resistant to further treatments. Based on gene mutations and expression profiles, glioblastoma is relatively well classified; however, research shows that there is more to glioblastoma biology than that defined solely by its genetic component. Specifically, the overall malignancy of the tumor is also influenced by the dynamic communication to its immediate and distant environment, as important messengers to neighboring cells in the tumor microenvironment extracellular vesicles (EVs) have been identified. EVs and their cargo can modulate the immune microenvironment and other physiological processes, and can interact with the host immune system. They are involved in tumor cell survival and metabolism, tumor initiation, progression, and therapy resistance. However, on the other hand EVs are thought to become an effective treatment alternative, since they can cross the blood-brain barrier, are able of specific cell-targeting and can be loaded with various therapeutic molecules.

Identification of novel biomarkers for intracerebral hemorrhage via long noncoding RNA-associated competing endogenous RNA network

Intracerebral hemorrhage (ICH) is a leading cause of death and disability worldwide. This study aimed to examine the involvement of long non-coding RNAs (lncRNAs), a group of non-coding transcripts, in ICH as potential biomarkers. An expression profile of patients with ICH using four contralateral grey matter controls (GM) and four contralateral white matter controls (WM) was downloaded from the Gene Expression Omnibus (GEO) database. Co-expressed lncRNAs and mRNAs were selected to create competing endogenous RNA (ceRNA) networks. Key lncRNAs were identified in ceRNA networks, which were validated through Real-time qPCR (RT-qPCR) with peripheral blood samples from patients with ICH. A total of 49 differentially expressed lncRNAs were discovered in different brain regions. The ceRNA network in GM included 9 lncRNAs, 40 mRNAs, and 20 microRNAs (miRNAs), while the one in WM covered 6 lncRNAs, 25 mRNAs, and 14 miRNAs. Six hub lncRNAs were observed and RT-qPCR results showed that LY86-AS1, DLX6-AS1, RRN3P2, and CRNDE were down-regulated, while HCP5 and MIAT were up-regulated in patients with ICH. Receiver Operating Characteristic (ROC) assessments demonstrated the diagnostic value of these lncRNAs. Our findings highlight the potential roles of lncRNA in ICH pathogenesis. Moreover, the hub lncRNAs discovered here might become novel biomarkers and promising targets for ICH drug development.

Long non-coding RNA panel as a molecular biomarker in glioma

BACKGROUND

Glioma is one of the most malignant brain tumors, accounting for about half of the gliomas that occur in central nervous system (CNS), originates from the glial tissue of the brain. The aim of the present study was to determine the expression levels of 5 lncRNAs (MDC1-AS1, HOXA11-AS, MALAT1, CASC2, ADAMTS9-AS2) in patients with high-grade glioma in comparison with low grade glioma.

METHODS

This was a retrospective study which determined molecular biomarker on pathologic glioma samples. We examined 100 patients' pathologic block which consisted of 50 pathology samples of high-grade glioma (case group) and control group consisted of 50 pathology samples of low-grade glioma. This research was performed using real time polymerase chain reaction (PCR) technique.

RESULTS

The results showed that the expression of ADAMTS9-AS2 and HOXA11-AS genes significantly increased with increasing tumor grade. Also the expression of CASC2 gene significantly decreased with increasing tumor grade.

CONCLUSIONS

It was concluded that ADAMTS9-AS2 and HOXA11-AS and CASC2 are promising lncRNA markers in prognosis of glioma.

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.

Taxifolin Targets PI3K and mTOR and Inhibits Glioblastoma Multiforme

Glioblastoma multiforme (GBM), the most common malignant primary brain tumor, has a very poor prognosis. With increasing knowledge of tumor molecular biology, targeted therapies are becoming increasingly integral to comprehensive GBM treatment strategies. mTOR is a key downstream molecule of the PI3K/Akt signaling pathway, integrating input signals from growth factors, nutrients, and energy sources to regulate cell growth and cell proliferation through multiple cellular responses. mTOR/PI3K dual-targeted therapy has shown promise in managing various cancers. Here, we report that taxifolin, a flavanone commonly found in milk thistle, inhibited mTOR/PI3K, promoted autophagy, and suppressed lipid synthesis in GBM. In silico analysis showed that taxifolin can bind to the rapamycin binding site of mTOR and the catalytic site of PI3K (p110α). In in vitro experiments, taxifolin inhibited mTOR and PI3K activity in five different glioma cell lines. Lastly, we showed that taxifolin suppressed tumors in mice; stimulated expression of autophagy-related genes LC3B-II, Atg7, atg12, and Beclin-1; and inhibited expression of fatty acid synthesis-related genes C/EBPα, PPARγ, FABP4, and FAS. Our observations suggest that taxifolin is potentially a valuable drug for treating GBM.

Dual role of microRNA-1297 in the suppression and progression of human malignancies

MicroRNAs (miRNAs) are endogenous, non-coding, single-stranded and tiny RNAs that modulate several biological functions, more importantly, the pathophysiology of numerous human cancers. They are bound with target mRNAs and thereby regulate gene expression at post-transcriptional levels. MiRNAs can either trigger cancer progression as an oncogene or alleviate it as a tumor suppressor. Abnormal expression of microRNA-1297 (miR-1297) has been noticed in several human cancers suggesting a distinct role for the miRNA in tumorigenesis. More specifically, it is both up-regulated and down-regulated in various cancers suggesting that it can act as both tumor suppressor and oncogene. This review systematically highlights the different roles of miR-1297 in the pathophysiology of human cancers, explains the mechanisms underlying miR-1297-mediated tumorigenesis, and discusses its potential prognostic, diagnostic, and therapeutic importance.

TP73-AS1 is induced by YY1 during TMZ treatment and highly expressed in the aging brain

Aging is a factor associated with poor prognosis in glioblastoma (GBM). It is therefore important to understand the molecular features of aging contributing to GBM morbidity. TP73-AS1 is a long noncoding RNA (lncRNA) over expressed in GBM tumors shown to promote resistance to the chemotherapeutic temozolomide (TMZ), and tumor aggressiveness. How the expression of TP73-AS1 is regulated is not known, nor is it known if its expression is associated with aging. By analyzing transcriptional data obtained from natural and pathological aging brain, we found that the expression of TP73-AS1 is high in pathological and naturally aging brains. YY1 physically associates with the promoter of TP73-AS1 and we found that along with TP73-AS1, YY1 is induced by TMZ. We found that the TP73-AS1 promoter is activated by TMZ, and by YY1 over expression. Using CRISPRi to deplete YY1, we found that YY1 promotes up regulation of TP73-AS1 and the activation of its promoter during TMZ treatment. In addition, we identified two putative YY1 binding sites within the TP73-AS1 promoter, and used mutagenesis to find that they are essential for TMZ mediated promoter activation. Together, our data positions YY1 as an important TP73-AS1 regulator, demonstrating that TP73-AS1 is expressed in the natural and pathological aging brain, including during neurodegeneration and cancer. Our findings advance our understanding of TP73-AS1 expression, bringing forth a new link between TMZ resistance and aging, both of which contribute to GBM morbidity.

Potential role of microRNAs as biomarkers in human glioblastoma: a mini systematic review from 2015 to 2020

Glioblastoma (GBM) is the most common, aggressive and malignant type of glioma, with poor prognosis, despite advances in medical knowledge and technology. It's known that some microRNAs (miRNAs) can be dysregulated and associated with tumors. We aim to investigate miRNAs that may have a role as potential biomarkers in human glioblastoma. A search was performed using PubMed, LILACS and SCIELO databases to find papers from 2015 to 2020, related to human in vitro and ex vivo data. From 99 articles, 10 were eligible and 13 dysregulated miRNAs were found with description of regulation, target(s), pathway(s) and mechanism(s). The miRNAs of interest were found and seem to be involved in development and progression of glioblastoma and used as target therapies. Understanding the mechanisms in which those miRNAs are involved and their role in epigenetic pathways that lead to cancer, as well as their potential in clinical application, may improve GBM clinical outcome (CRD42020182706, 07/10/2020, retrospectively registered).

Long noncoding RNA DLGAP1-AS1 promotes the progression of glioma by regulating the miR-1297/EZH2 axis

Dysregulated lncRNAs have been implicated in a plethora of tumors, including glioma. One such oncogenic lncRNAs that has been reported in several cancers is the lncRNA DLGAP1 antisense RNA 1 (DLGAP1-AS1). This study seeks to characterize the expression of DLGAP1-AS1 in glioma tissues, which we found to be raised in both glioma samples and cell lines. Functional experiments revealed that DLGAP1-AS1 promoted in vitro glioma cell invasion, migration and proliferation. DLGAP1-AS1 was found to function as a miR-1297 sponge, based on information from luciferase reporter assays, RNA pull-down assays and publicly available online databases. miR-1297 was in turn found to functionally target EZH2. DLGAP1-AS1 modulated EZH2 expressions through miR-1297 sponging. Glioma progression appears to be supported DLGAP1-AS1 -promoted activation of the miR-1297/EZH2 axis. The components of this axis may function as therapeutic targets for glioma.

LncRNAs associated with glioblastoma: From transcriptional noise to novel regulators with a promising role in therapeutics

Glioblastoma multiforme (GBM) is the most widespread and aggressive subtype of glioma in adult patients. Numerous long non-coding RNAs (lncRNAs) are deregulated or differentially expressed in GBM. These lncRNAs possess unique regulatory functions in GBM cells, ranging from high invasion/migration to recurrence. This review outlines the present status of specific involvement of lncRNAs in GBM pathogenesis, with a focus on their association with key molecular and cellular regulatory mechanisms. Also, we highlighted the potential of different novel RNA-based strategies that may be beneficial for therapeutic purposes.

Long Non-Coding RNAs in Multidrug Resistance of Glioblastoma

Glioblastoma, also known as glioblastoma multiforme, is the most aggressive brain tumor in adults. Despite the huge advance in developing novel therapeutic strategies for patients with glioblastoma, the appearance of multidrug resistance (MDR) against the common chemotherapeutic agents, including temozolomide, is considered as one of the important causes for the failure of glioblastoma treatment. On the other hand, recent studies have demonstrated the critical roles of long non-coding RNAs (lncRNAs), particularly in the development of MDR in glioblastoma. Therefore, this article aimed to review lncRNA's contribution to the regulation of MDR and elucidate the underlying mechanisms in glioblastoma, which will open up new lines of inquiry in the treatment of glioblastoma.

LncRNA-Gm9795 promotes inflammation in non-alcoholic steatohepatitis via NF- κ B/JNK pathway by endoplasmic reticulum stress

BACKGROUND

Non-alcoholic steatohepatitis (NASH) is a key stage in leading development of non-alcoholic simple fatty liver (NAFL) into cirrhosis and even liver cancer. This study aimed at exploring the lncRNAs expression profile in NASH and the biological function of a novel LncRNA-gm9795.

METHODS

Microarray analysis was performed to compare the expression profiles of lncRNAs in the liver of NASH, NAFLD and normal mice (5 mice for each group). Methionine-choline-deficient Medium (MCD) with Lipopolysaccharide (LPS) or palmitic acid (PA)were used to built NASH cell models. The role and mechanism of LncRNA-gm9795 in NASH were explored by knocking down or over-expressing its expression.

RESULTS

A total of 381 lncRNAs were found to be not only highly expressed in NAFLD, but also is going to go even higher in NASH. A novel LncRNA-gm9795 was significantly highly expressed in liver tissues of NASH animal models and NASH cell models. By staining with Nile red, we found that gm9795 did not affect the fat accumulation of NASH. However, gm9795 in NASH cell models significantly promoted the expression of TNFα , IL-6, IL-1β , the important inflammatory mediators in NASH. At the same time, we found that gm9795 upregulated the key molecules in endoplasmic reticulum stress (ERS), while NFκ B/JNK pathways were also activated. When ERS activator Thapsigargin (TG) was introduced in cells with Ggm9757 si-RNA, NF-κ B and JNK pathways were activated. Conversely, ERS inhibitor Tauroursodeoxycholic acid (TUDCA) inhibited NF-kB and JNK pathways in cells with gm9795 overexpression plasmid.

CONCLUSION

LncRNA-gm9795 promotes inflammatory response in NASH through NF-kB and JNK pathways by ERS, which might provide theoretical basis for revealing the pathogenesis of NASH and discovering new therapeutic targets.

Analysis of Long Noncoding RNA ZNF667-AS1 as a Potential Biomarker for Diagnosis and Prognosis of Glioma Patients

Objective

Long noncoding RNAs (lncRNAs) have been strongly associated with various types of cancer. The present study aimed at exploring the diagnostic and prognostic value of lncRNA Zinc finger protein 667-antisense RNA 1 (ZNF667-AS1) in glioma patients. Patients and Methods. The expressions of ZNF667-AS1 were detected in 155 glioma tissues and matched normal brain tissue samples by qRT-PCR. The receiver operating characteristic (ROC) curve was performed to estimate the diagnostic value of ZNF667-AS1. The association between the ZNF667-AS1 expression and clinicopathological characteristics was analyzed by the chi-square test. The Kaplan-Meier method was performed to determine the influence of the ZNF667-AS1 expression on the overall survival and disease-free survival of glioma patients. The Cox regression analysis was used to evaluate the effect of independent prognostic factors on survival outcome. Cell proliferation was measured by the respective cell counting Kit-8 (CCK-8) assays.

Results

We observed that ZNF667-AS1 was significantly upregulated in glioma tissues compared to normal tissue samples (p < 0.01). Higher levels of ZNF667-AS1 were positively associated with the WHO grade (p = 0.018) and KPS score (p = 0.008). ROC assays revealed that the high ZNF667-AS1 expression had an AUC value of 0.8541 (95% CI: 0.8148 to 0.8934) for glioma. Survival data revealed that glioma patients in the high ZNF667-AS1 expression group had significantly shorter 5-year overall survival (p = 0.0026) and disease-free survival (p = 0.0005) time than those in the low ZNF667-AS1 expression group. Moreover, multivariate analyses confirmed that the ZNF667-AS1 expression was an independent predictor of the overall survival and disease-free survival for glioma patients. Functionally, we found that knockdown of ZNF667-AS1 suppressed the proliferation of glioma cells.

Conclusions

Our results suggest that ZNF667-AS1 could be used as a potential diagnostic and prognostic biomarker in glioma.

Diagnostic and Prognostic Potentials of Long Noncoding RNA ELF3-AS1 in Glioma Patients

Objective

Accumulating evidence implies that long noncoding RNAs (lncRNAs) play a crucial role in predicting survival for glioma patients. However, the potential function of lncRNA ELF3-antisense RNA 1 (ELF3-AS1) in tumors remained largely unclear. The aim of this study was to explore the expression of lncRNA ELF3-antisense RNA 1 (ELF3-AS1) and evaluate its functions in glioma patients. Patients and Methods. ELF3-AS1 expressions were examined by RT-PCR in 182 pairs of glioma specimens and adjacent normal tissues. The receiver operating characteristic (ROC) curve was performed to estimate the diagnostic value of ELF3-AS1. The chi-square tests were used to examine the associations between ELF3-AS1 expression and the clinicopathological characters. The overall survival (OS) and disease-free survival (DFS) were analyzed by log-rank test, and survival curves were plotted according to Kaplan-Meier. The prognostic value of the ELF3-AS1 expression in glioma patients was further analyzed using univariate and multivariate Cox regression analyses. Loss-of-function assays were performed to determine the potential function of ELF3-AS1 on the proliferation and invasion of glioma cells.

Results

The ELF3-AS1 expression level was significantly higher in glioma specimens compared with adjacent nontumor specimens (p < 0.01). A high expression of ELF3-AS1 was shown to be associated with the WHO grade (p = 0.023) and KPS score (p = 0.012). ROC assays revealed that high ELF3-AS1 expression had an AUC value of 0.8073 (95% CI: 0.7610 to 0.8535) for glioma. Using the Kaplan-Meier analysis, we found that patients with a high ELF3-AS1 expression had significantly poor OS (p = 0.006) and DFS (p = 0.0002). In a multivariate Cox model, we confirmed that ELF3-AS1 expression was an independent poor prognostic factor for glioma patients. The functional assay revealed that knockdown of ELF3-AS1 suppressed the proliferation and invasion of glioma cells.

Conclusions

Our findings confirmed that ELF3-AS1 functions as an oncogene in glioma and indicated that ELF3-AS1 is not only an important prognostic marker but also a potential therapy target for glioma.

Long non-coding RNAs as epigenetic mediator and predictor of glioma progression, invasiveness, and prognosis

Gliomas are aggressive brain tumors with high mortality rate. Over the past several years, non-coding RNAs, specifically the long non-coding RNAs (lncRNAs), have emerged as biomarkers of considerable interest. Emerging data reveals distinct patterns of expressions of several lncRNAs in the glioma tissues, relative to their expression in normal brains. This has led to the speculation for putative exploitation of lncRNAs as diagnostic biomarkers as well as biomarkers for targeted therapy. With a focus on lncRNAs that have shown promise as epigenetic biomarkers in the proliferation, migration, invasion, angiogenesis and metastasis in various glioma models, we discuss several such lncRNAs. The data from cell line / animal model-based studies as well as analysis from human patient samples is presented for the most up-to-date information on the topic. Overall, the information provided herein makes a compelling case for further evaluation of lncRNAs in clinical settings.