Development of stemness-related signature to optimize prognosis prediction and identify XMD8-85 as a novel therapeutic compound for glioma.

Glioma is a highly invasive and aggressive type of brain cancer with poor treatment response. Stemness-related transcription factors form a regulatory network that sustains the malignant phenotype of gliomas. We conducted an integrated analysis of stemness-related transcription factors using The Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) datasets, established the characteristics of stemness-related transcription factors, including Octamer-Binding Protein 4 (OCT4), Meis Homeobox 1 (MEIS1), E2F Transcription Factor 1 (E2F1), Transcription Factor CP2 Like 1 (TFCP2L1), and RUNX Family Transcription Factor 1 (RUNX1). The characteristic of stemness-related transcription factors was identified as an independent prognostic factor for glioma patients. Patients in the high-risk group have a worse prognosis than those in the low-risk group. The glioma microenvironment in the high-risk group exhibited a more active immune status. Single-cell level analysis revealed that stem cell-like cells exhibited stronger intercellular communication than glioma cells. Meanwhile, patients in different risk stratification exhibited varying sensitivities to immunotherapy and small molecule drug therapy. XMD8-85 was more effective in the high-risk group, and its antitumor effects were validated both in vivo and in vitro. Our results indicate that this prognostic feature will assist clinicians in predicting the prognosis of glioma patients, guiding immunotherapy and personalized treatment, as well as the potential clinical application of XMD8-85 in glioma treatment, and helping to develop effective treatment strategies.

Lycorine hydrochloride interferes with energy metabolism to inhibit chemoresistant glioblastoma multiforme cell growth through suppressing PDK3.

Glioblastoma multiforme (GBM) is the highest grade of glioma. Tumours, including GBM, possess reprogrammed metabolism, such as altered aerobic glycolysis and aberrant energy production. Lycorine hydrochloride (LH) was extracted from the bulb of Lycoris radiata. The previous study indicated that LH exerts antiviral, anti-inflammatory and antitumour effects. However, the effect of LH on GBM and the underlying molecular mechanism remain unclear. Our study revealed that LH restrained chemoresistant GBM cells growth by inhibiting PDK3 expression in vitro and in vivo. Functionally, LH inhibited the proliferation and invasive capacity of chemoresistant GBM cells in dose-dependent manner. Metabolomics and cellular energy analyses showed that LH decreased extracellular acidification rates while increased oxidative respiration and ROS levels. Mechanistically, LH inhibits the growth of GBM chemoresistant cells by regulating the expression of apoptosis-related proteins, while overexpression of of PDK3 can reverse the antitumor effect of LH. In conclusion, our study revealed that LH could reprogramme cell energy metabolism, including aerobic glycolysis suppression and oxidative phosphorylation hyperactivation by inhibiting PDK3. PDK3 may be a candidate therapeutic target for chemoresistant GBM treatment with LH.

Blocking Palmitoylation of Apelin Receptor Alleviates Morphine Tolerance in Neuropathic Cancer Pain.

Neuropathic cancer pain (NCP) is an important symptom in patients with cancer. However, significant analgesic tolerance and other side effects critically hamper the administration of morphine. Protein palmitoylation mediated by the DHHC family may be involved in the glial activation and inflammatory responses underlying organ failure. In this study, we investigated the key role of protein palmitoylation in cancer pain and sought to target palmitoylation to suppress morphine tolerance. We found that long-term use of morphine led to the accumulation of the morphine metabolite, morphine-3-glucuronide, in vivo and activated ERK1/2 and microglia to release inflammatory factors through the apelin receptor APLNR. Palmitoyltransferase ZDHHC9 was upregulated in NCP, and APLNR was palmitylated to protect it from lysosomal degradation and to maintain its stability. We also designed competitive inhibitors of APLNR palmitoylation to inhibit the development of NCP, release of inflammatory factors, and attenuation of morphine tolerance. Therefore, targeting APLNR palmitoylation in combination with morphine is a potent method for cancer pain treatment. Our data provide a basis for the future clinical use of related drugs combined with morphine for the treatment of cancer-related pain.

GTF2E2 downregulated by miR-340-5p inhibits the malignant progression of glioblastoma.

Glioblastoma is the most common malignant tumor in the central nervous system. The general transcription factor IIE subunit beta (GTF2E2) is crucial for physiological and pathological functions, but its roles in the malignant biological function of glioma remain ambiguous. CCK-8, colony formation assays, TUNEL assays, cell migration assays, wound-healing assays, and xenograft model were established to investigate the biological functions of GTF2E2 both in vitro and in vivo. GTF2E2 was overexpressed in glioma and was associated with poor prognosis of glioma patients. Biological functions of GTF2E2 were investigated both in vitro and in vi0vo by multiple experiments. Moreover, we explored the possible mechanisms of GTF2E2. In our results, we demonstrated that GTF2E2 could be regulated by miR-340-5p directly or indirectly. CCND1 was transcriptionally affected by GTF2E2 and glioma progression was then regulated. Our data presented the overexpression of GTF2E2 in glioma and indicated the association between GTF2E2 and glioma prognosis. GTF2E2 was found to be regulated by miR-340-5p and thus affect downstream gene expressions and glioma progression. Our results indicate that GTF2E2 might be a potential target in the diagnosis and treatments of glioblastoma.

CircSOBP suppresses the progression of glioma by disrupting glycolysis and promoting the MDA5-mediated immune response.

Glioma, an aggressively growing and highly malignant brain tumor, poses substantial therapeutic challenges due to its resistance to radiotherapy and chemotherapy. Recent research has identified circRNAs as pivotal players in glioma formation and development. However, the roles of circRNA in the metabolic and immune regulation of glioma are unclear. In this study, circSOBP expression was significantly downregulated in glioma cells and specimens. Functionally, enhanced circSOBP expression mitigated cell proliferation, invasion, migration, and glycolysis in gliomas. Mechanistically, circSOBP inhibited glycolysis and activated the MDA5-mediated IKKε/TBK1/IRF3 signaling pathway by binding TKFC proteins. Furthermore, the elevated levels of IFN-I induced by the MDA5 pathway increased the number and activity of CD8+ T and NK cells in the immune response of the animal models. In summary, our findings have emphasized the critical role of circSOBP in binding and modulating TKFC protein, offering potential therapeutic avenue for targeting glioma metabolism and immunological reprogramming.

Loss of p53 Concurrent with RAS and TERT Activation Induces Glioma Formation.

There is an ongoing debate regarding whether gliomas originate due to functional or genetic changes in neural stem cells (NSCs). Genetic engineering has made it possible to use NSCs to establish glioma models with the pathological features of human tumors. Here, we found that RAS, TERT, and p53 mutations or abnormal expression were associated with the occurrence of glioma in the mouse tumor transplantation model. Moreover, EZH2 palmitoylation mediated by ZDHHC5 played a significant role in this malignant transformation. EZH2 palmitoylation activates H3K27me3, which in turn decreases miR-1275, increases glial fibrillary acidic protein (GFAP) expression, and weakens the binding of DNA methyltransferase 3A (DNMT3A) to the OCT4 promoter region. Thus, these findings are significant because RAS, TERT, and p53 oncogenes in human neural stem cells are conducive to a fully malignant and rapid transformation, suggesting that gene changes and specific combinations of susceptible cell types are important factors in determining the occurrence of gliomas.

Oct4A palmitoylation modulates tumorigenicity and stemness in human glioblastoma cells.

BACKGROUND: Glioblastoma multiforme and other solid malignancies are heterogeneous, containing subpopulations of tumor cells that exhibit stem characteristics. Oct4, also known as POU5F1, is a key transcription factor in the self-renewal, proliferation, and differentiation of stem cells. Although it has been detected in advanced gliomas, the biological function of Oct4, and transcriptional machinery maintained by the stemness of Oct4 protein-mediated glioma stem cells (GSC), has not been fully determined. METHODS: The expression of Oct4 variants was evaluated in brain cancer cell lines, and in brain tumor tissues, by quantitative real-time PCR, western blotting, and immunohistochemical analysis. The palmitoylation level of Oct4A was determined by the acyl-biotin exchange method, and the effects of palmitoylation Oct4A on GSCs were investigated by a series of in vitro (neuro-sphere formation assay, double immunofluorescence, pharmacological treatment, luciferase assay, and coimmunoprecipitation) and in vivo (xenograft model) experiments. RESULTS: Here, we report that all three variants of Oct4 are expressed in different types of cerebral cancer, while Oct4A is important for maintaining tumorigenicity in GSCs. Palmitoylation mediated by ZDHHC17 was indispensable for preserving Oct4A from lysosome degradation to maintain its protein stability. Oct4A palmitoylation also helped to integrate Sox4 and Oct4A in the SOX2 enhancement subregion to maintain the stem performance of GSCs. We also designed Oct4A palmitoylation competitive inhibitors, inhibiting the self-renewal ability and tumorigenicity of GSCs. CONCLUSIONS: These findings indicate that Oct4A acts on the tumorigenic activity of glioblastoma, and Oct4A palmitoylation is a candidate therapeutic target.

Exosomal miR-155-5p derived from glioma stem-like cells promotes mesenchymal transition via targeting ACOT12.

Tumor-associated exosomes play essential roles in intercellular communication and the foundation of cancer microenvironment in glioma. Many mRNAs, microRNAs (miRNAs) and proteins contained in tumor-associated exosomes can be transferred to recipient cells and contribute to the progression of tumor. Nevertheless, the cellular communication between malignant cells with different heterogeneities or characteristics and resultant tumor progression are still unclear in glioma. Here, we show that exosomes released from glioma stem-like cells (GSCs) contain a significant increasing level of miR-155-5p and could be horizontally transferred to surrounding glioma cells. High expression of miR-155-5p in plasma exosomes from patients was associated with glioma diagnosis and grading. Mechanically, we found that miR-155-5p markedly reduced the expression of acetyl-CoA thioesterase 12 (ACOT12), which played as a tumor suppressor in glioma. Furthermore, mesenchymal transition was significantly promoted in glioma cells treated with GSCs-derived exosomes. In conclusion, GSCs-derived exosomal miR-155-5p play a critical role in glioma progression and facilitating tumor aggressive growth by targeting ACOT12 and promoting mesenchymal transition. Exosomal miR-155-5p is also a potential predictive biomarker for glioma, which may provoke the development of novel diagnostic and therapeutic strategies against glioma.

Systematic transcriptome profiling of pyroptosis related signature for predicting prognosis and immune landscape in lower grade glioma.

BACKGROUND: Pyroptosis is a programmed cell death mediated by the gasdermin superfamily, accompanied by inflammatory and immune responses. Exogenously activated pyroptosis is still not well characterized in the tumor microenvironment. Furthermore, whether pyroptosis-related genes (PRGs) in lower-grade glioma (LGG) may be used as a biomarker remains unknown. METHODS: The RNA-Sequencing and clinical data of LGG patients were downloaded from publicly available databases. Bioinformatics approaches were used to analyze the relationship between PRGs and LGG patients' prognosis, clinicopathological features, and immune status. The NMF algorithm was used to differentiate phenotypes, the LASSO regression model was used to construct prognostic signature, and GSEA was used to analyze biological functions and pathways. The expression of the signature genes was verified using qRT-PCR. In addition, the L1000FWD and CMap tools were utilized to screen potential therapeutic drugs or small molecule compounds and validate their effects in glioma cell lines using CCK-8 and colony formation assays. RESULTS: Based on PRGs, we defined two phenotypes with different prognoses. Stepwise regression analysis was carried out to identify the 3 signature genes to construct a pyroptosis-related signature. After that, samples from the training and test cohorts were incorporated into the signature and divided by the median RiskScore value (namely, Risk-H and Risk-L). The signature shows excellent predictive LGG prognostic power in the training and validation cohorts. The prognostic signature accurately stratifies patients according to prognostic differences and has predictive value for immune cell infiltration and immune checkpoint expression. Finally, the inhibitory effect of the small molecule inhibitor fedratinib on the viability and proliferation of various glioma cells was verified using cell biology-related experiments. CONCLUSION: This study developed and validated a novel pyroptosis-related signature, which may assist instruct clinicians to predict the prognosis and immunological status of LGG patients more precisely. Fedratinib was found to be a small molecule inhibitor that significantly inhibits glioma cell viability and proliferation, which provides a new therapeutic strategy for gliomas.

Gliosarcoma: The Distinct Genomic Alterations Identified by Comprehensive Analysis of Copy Number Variations.

Gliosarcoma (GSM), a histologic variant of glioblastoma (GBM), carries a poor prognosis with less than one year of median survival. Though GSM is similar with GBM in most clinical and pathological symptoms, GBM has unique molecular and histological features. However, as the rarity of GSM samples, the genetic information of this tumor is still lacking. Here, we take a comprehensive analysis of DNA copy number variations (CNV) in GBM and GSM. Whole genome sequencing was performed on 21 cases of GBM and 15 cases of GSM. CNVKIT is used for CNV calling. Our data showed that chromosomes 7, 8, 9, and 10 were the regions where CNV frequently happened in both GBM and GSM. There was a distinct CNV signal in chromosome 2 especially in GSM. The pathway enrichment of genes with CNV was suggested that the GBM and GSM shared the similar mechanism of tumor development. However, the CNV of some screened genes displayed a disparate form between GBM and GSM, such as AMP, BEND2, HDAC6, FOXP3, ZBTB33, TFE3, and VEGFD. It meant that GSM was a distinct subgroup possessing typical biomarkers. The pathways and copy number alterations detected in this study may represent key drivers in gliosarcoma oncogenesis and may provide a starting point toward targeted oncologic analysis with therapeutic potential.

GSK3ß palmitoylation mediated by ZDHHC4 promotes tumorigenicity of glioblastoma stem cells in temozolomide-resistant glioblastoma through the EZH2-STAT3 axis.

Glioblastoma stem cells (GSCs) are a highly tumorigenic cell subgroup of glioblastoma (GBM). Glycogen synthase kinase 3ß (GSK3ß) is considered a key hub for promoting malignant phenotypes in GBM. However, the functional relationships between GSK3ß and GSCs in GBM are unclear. Here, we found that GSK3ß was noted as a substrate for ZDHHC4-mediated palmitoylation at the Cys14 residue, which enhanced GBM temozolomide (TMZ) resistance and GSC self-renewal. Clinically, the expression level of ZDHHC4 was upregulated in GBM, which significantly correlated with tumor grade and poor prognosis. The above phenotypes were based on decreasing p-Ser9 and increasing p-Tyr216 by GSK3ß palmitoylation, which further activated the enhancer of the zeste homolog 2 (EZH2)-STAT3 pathway. Notably, STAT3 silencing also inhibited ZDHHC4 expression. This study revealed that GSK3ß palmitoylation mediated by ZDHHC4 improved the stemness of TMZ-resistant GBM by activating the EZH2-STAT3 signaling axis, providing a new theoretical basis for further understanding the mechanism of TMZ resistance and recurrence after treatment.

SETD2 Palmitoylation Mediated by ZDHHC16 in Epidermal Growth Factor Receptor-Mutated Glioblastoma Promotes Ionizing Radiation-Induced DNA Damage.

PURPOSE: The prevalence of epidermal growth factor receptor (EGFR) mutations in glioblastoma multiforme (GBM) has elicited a significant focus on EGFR as a potential drug target. However, no significant clinical advancement in GBM treatment has occurred. METHODS AND MATERIALS: Bioinformatics analysis, western blotting, immunofluorescence, and immunohistochemistry were performed to detect the expression of ZDHHC16 and genetic EGFR alterations in GBM. The biological function of ZDHHC16/SETD2/H3K36me3 signaling axis after EGFR alterations was demonstrated by various in vitro (pharmacologic treatment, flow cytometry, transwell migration assay, and coimmunoprecipitation) and in vivo (xenograft model) experiments. RESULTS: We demonstrate that the ZDHHC16/SETD2/H3K36me3 signaling axis was inactivated in EGFR-altered GBM. ZDHHC16 was downregulated in GBM versus normal brain tissue; this was significantly related to EGFR alterations. These events contributed to p53 activation, halting cells at the G1/S checkpoint. Furthermore, DNA damage repair signaling in EGFR-amplified GBMs was affected after ionizing radiation-induced DNA damage via reduced SETD2 palmitoylation and methylation of its target, H3K36. Our findings suggest that a depalmitoylation inhibitor, PalmB, is useful as a potentially novel adjuvant treatment for patients with GBM undergoing radiation therapy. CONCLUSIONS: Our data present novel mechanistic evidence relating to signaling pathways with DNA damage responses in EGFR-mutated GBM.

Differential expression and significance of miRNAs in plasma extracellular vesicles of patients with Parkinson's disease.

OBJECTIVE: To study the feasibility of plasma extracellular vesicles (EVs) miRNAs as diagnostic biomarkers for Parkinson's disease (PD). METHODS: Plasma EVs were isolated from 30 PD patients and 30 age- and sex-matched healthy controls. Plasma EVs miRNAs were analysed by qRT-PCR. SH-SY5Y cells were induced by different concentrations of 1-Methyl-4-phenil-pyridinium (MPP+) to obtain PD cellular model. The levels of miRNAs and α-synuclein (α-syn) in PD cellular model were analysed by qRT-PCR and Western blot. Receiver operating characteristic (ROC) curve analysis was performed to determine the diagnostic usefulness of the miRNAs in plasma EVs for PD. The gene ontology (GO) and KEGG pathways of the target genes of miRNAs were analysed by softwares. RESULTS: The level of hsa-miR-30c-2-3p in plasma EVs was significantly higher in PD patients than that in controls, and the levels of hsa-miR-15b-5p, hsa-miR-138-5p, hsa-miR-338-3p, hsa-miR-106b-3p and hsa-miR-431-5p in plasma EVs were lower in PD patients than that in controls. When compared with the control group, the area under the curve (AUC) values for hsa-miR-15b-5p, hsa-miR-30c-2-3p, hsa-miR-138-5p, hsa-miR-431-5p, hsa-miR-338-3p and hsa-miR-106b-3p were all greater than 0.6. The target genes of hsa-miR-15b-5p, hsa-miR-30c-2-3p, hsa-miR-138-5p and hsa-miR-338-3p were enriched in dopaminergic synapse and PD pathway. CONCLUSIONS: The hsa-miR-15b-5p, hsa-miR-30c-2-3p, hsa-miR-138-5p, hsa-miR-106b-3p, hsa-miR-338-3p and hsa-miR-431-5p may be used as potential biomarkers for the diagnosis of PD, and the combined diagnostic accuracy of hsa-miR-15b-5p, hsa-miR-30c-2-3p, hsa-miR-138-5p and hsa-miR-106b-3p was better. The target genes of hsa-miR-15b-5p, hsa-miR-30c-2-3p, hsa-miR-138-5p and hsa-miR-338-3p may regulate the expression of dopamine by dopaminergic synapse and PD pathway.HighlightsIsolation and identification of plasma EVs.The miRNAs in plasma EVs may be used as potential biomarkers for the diagnosis of PD.When SH-SY5Y cells were induced by different concentrations of MPP+, the levels of miRNAs and α-syn changed gradually.The target genes of miRNAs were enriched in dopaminergic synapse and PD pathway.The target genes of miRNAs may regulate the expression of dopamine.

Heterogeneity of subsets in glioblastoma mediated by Smad3 palmitoylation.

Glioblastoma (GBM) is the most common and deadly of the primary intracranial tumors and is comprised of subsets that show plasticity and marked heterogeneity, contributing to the lack of success in genomic profiling to guide development of precision medicine for these tumors. In this study, a mutation in isocitrate dehydrogenase 1 was found to suppress the transforming growth factor-beta signaling pathway and E2F4 interacted with Smad3 to inhibit expression of mesenchymal markers. However, palmitoylation of Smad3 mediated by palmitoyltransferase ZDHHC19 promoted activation of the transforming growth factor-beta signaling pathway, and its interaction with EP300 promoted expression of mesenchymal markers in the mesenchymal subtype of GBM. Smad3 and hypoxia-inducible factor 1-alpha may be important molecular targets for treatment of glioma because they appear to coordinate the basic aspects of cancer stem cell biology.

Interleukin-22 Plays a Protective Role by Regulating the JAK2-STAT3 Pathway to Improve Inflammation, Oxidative Stress, and Neuronal Apoptosis following Cerebral Ischemia-Reperfusion Injury.

The interleukins (ILs) are a pluripotent cytokine family that have been reported to regulate ischemic stroke and cerebral ischemia/reperfusion (I/R) injury. IL-22 is a member of the IL-10 superfamily and plays important roles in tissue injury and repair. However, the effects of IL-22 on ischemic stroke and cerebral I/R injury remain unclear. In the current study, we provided direct evidence that IL-22 treatment decreased infarct size, neurological deficits, and brain water content in mice subjected to cerebral I/R injury. IL-22 treatment remarkably reduced the expression of inflammatory cytokines, including IL-1ß, monocyte chemotactic protein- (MCP-) 1, and tumor necrosis factor- (TNF-) α, both in serum and the ischemic cerebral cortex. In addition, IL-22 treatment also decreased oxidative stress and neuronal apoptosis in mice after cerebral I/R injury. Moreover, IL-22 treatment significantly increased Janus tyrosine kinase (JAK) 2 and signal transducer and activator of transcription (STAT) 3 phosphorylation levels in mice and PC12 cells, and STAT3 knockdown abolished the IL-22-mediated neuroprotective function. These findings suggest that IL-22 might be exploited as a potential therapeutic agent for ischemic stroke and cerebral I/R injury.

Osimertinib successfully combats EGFR-negative glioblastoma cells by inhibiting the MAPK pathway.

Glioblastoma (GBM) patients have extremely poor prognoses, and currently no effective treatment available including surgery, radiation, and chemotherapy. MAPK-interacting kinases (MNK1/2) as the downstream of the MAPK-signaling pathway regulate protein synthesis in normal and tumor cells. Research has shown that targeting MNKs may be an effective strategy to treat GBM. In this study we investigated the antitumor activity of osimertinib, an FDA-approved epidermal growth factor receptor (EGFR) inhibitor, against patient-derived primary GBM cells. Using high-throughput screening approach, we screened the entire panel of FDA-approved drugs against primary cancer cells derived from glioblastoma patients, found that osimertinib (3 µM) suppressed the proliferation of a subset (10/22) of EGFR-negative GBM cells (>50% growth inhibition). We detected the gene expression difference between osimertinib-sensitive and -resistant cells, found that osimertinib-sensitive GBM cells displayed activated MAPK-signaling pathway. We further showed that osimertinib potently inhibited the MNK kinase activities with IC50 values of 324 nM and 48.6 nM, respectively, against MNK1 and MNK2 kinases; osimertinib (0.3-3 µM) dose-dependently suppressed the phosphorylation of eukaryotic translation initiation factor 4E (eIF4E). In GBM patient-derived xenografts mice, oral administration of osimertinib (40 mg· kg-1 ·d-1, for 18 days) significantly suppressed the tumor growth (TGI = 74.5%) and inhibited eIF4E phosphorylation in tumor cells. Given the fact that osimertinib could cross the blood-brain barrier and its toxicity was well tolerated in patients, our results suggest that osimertinib could be a new and effective drug candidate for the EGFR-negative GBM patients.

Long non-coding RNA LPP-AS2 promotes glioma tumorigenesis via miR-7-5p/EGFR/PI3K/AKT/c-MYC feedback loop.

BACKGROUND: Glioblastoma is the most common primary malignant intracranial tumor with poor clinical prognosis in adults. Accumulating evidence indicates that long non-coding RNAs (lncRNAs) function as important regulators in cancer progression, including glioblastoma. Here, we identified a new lncRNA LPP antisense RNA-2 (LPP-AS2) and investigated its function and mechanism in the development of glioma. METHODS: High-throughput RNA sequencing was performed to discriminate differentially expressed lncRNAs and mRNAs between glioma tissues and normal brain tissues. Expression of LPP-AS2, epidermal growth factor receptor (EGFR) and miR-7-5p in glioma tissues and cell lines was detected by real-time quantitative PCR (RT-qPCR), and the functions of lncRNA LPP-AS2 in glioma were assessed by in vivo and in vitro assays. Insight into the underlying mechanism of competitive endogenous RNAs (ceRNAs) was obtained via bioinformatic analysis, dual luciferase reporter assays, RNA pulldown assays, RNA immunoprecipitation (RIP) and rescue experiments. RESULTS: The results of high-throughput RNA-seq indicated lncRNA LPP-AS2 was upregulated in glioma tissues and further confirmed by RT-qPCR. Higher LPP-AS2 expression was related to a poor prognosis in glioma patients. Based on functional studies, LPP-AS2 depletion inhibited glioma cell proliferation, invasion and promoted apoptosis in vitro and restrained tumor growth in vivo, overexpression of LPP-AS2 resulted in the opposite effects. In addition, LPP-AS2 and EGFR were observed in co-expression networks. LPP-AS2 was found to function as a ceRNA to regulate EGFR expression by sponging miR-7-5p in glioma cells. The result of chromatin immunoprecipitation (ChIP) assays validated that c-MYC binds directly to the promoter region of LPP-AS2. As a downstream protein of EGFR, c-MYC was modulated by LPP-AS2 and in turn enhanced LPP-AS2 expression. Thus, lncRNA LPP-AS2 promoted glioma tumorigenesis via a miR-7-5p/EGFR/PI3K/AKT/c-MYC feedback loop. CONCLUSIONS: Our study elucidated that LPP-AS2 acted as an oncogene through a novel molecular pathway in glioma and might be a potential therapeutic approach for glioma diagnosis, therapy and prognosis.

LncRNA BCYRN1 inhibits glioma tumorigenesis by competitively binding with miR-619-5p to regulate CUEDC2 expression and the PTEN/AKT/p21 pathway.

Glioma is the most common malignant tumor in the central nervous system. Altered long noncoding RNAs (lncRNAs) are playing regulatory roles in physiological and pathogenic processes in cancer. Here, we uncovered a differentially expressed lncRNA called brain cytoplasmic RNA 1 (BCYRN1), and elucidated its function and molecular mechanism in the progression and development of glioma. Three fresh tumor tissues from glioma patients and three normal brain tissues from craniocerebral trauma patients were prepared for high-throughput RNA sequencing. Differential RNA transcripts and BCYRN1 were identified by RT-qPCR in glioma samples and controls. CCK-8, colony formation assays, flow cytometry, TUNEL assays, cell migration assays, wound-healing assays, and xenograft model were established to investigate the biological function of BCYRN1 both in vitro and in vivo. Various bioinformatics analysis, dual-luciferase reporter assays, biotinylated RNA pulldown assays, and rescue experiments were conducted to reveal the underlying mechanisms of competitive endogenous RNAs (ceRNAs). 183 lncRNAs were identified with significant dysregulation in glioma and randomly selected differential RNAs were further confirmed by RT-qPCR. Among them, BCYRN1 was the most downregulated lncRNA, and its low expression positively correlated with glioma progression. Functionally, BCYRN1 overexpression inhibited cell proliferation, migration in glioma cell lines, whereas BCYRN1 depletion resulted in the opposite way. MiR-619-5p was further confirmed as the direct target of BCYRN1. Mechanistically, miR-619-5p specifically targeted the CUE domain containing protein 2 (CUEDC2), and BCYRN1/miR-619-5p suppressed glioma tumorigenesis by inactivating PTEN/AKT/p21 pathway in a CUEDC2-dependent manner. Overall, our data presented that the reduced expression of BCYRN1 was associated with poor patient outcome in glioma. BCYRN1 functioned as a ceRNA to inhibit glioma progression by sponging miR-619-5p to regulate CUEDC2 expression and PTEN/AKT/p21 pathway. Our results indicated that BCYRN1 exerted tumor suppressor potential and might be a candidate in the diagnosis and treatment of glioma.