Transcriptome Analysis and Single-Cell Sequencing Analysis Constructed the Ubiquitination-Related Signature in Glioma and Identified USP4 as a Novel Biomarker.

Background: Glioma, the most frequent malignant tumor of the neurological system, has a poor prognosis and treatment problems. Glioma's tumor microenvironment is also little known. Methods: We downloaded glioma data from the TCGA database. The patients in the TCGA database were split into two groups, one for training and the other for validation. The ubiquitination genes were then evaluated in glioma using COX and Lasso regression to create a ubiquitination-related signature. We assessed the signature's predictive usefulness and role in the immune microenvironment after it was generated. Finally, in vitro experiment were utilized to check the expression and function of the signature's key gene, USP4. Results: This signature can be used to categorize glioma patients. Glioma patients can be separated into high-risk and low-risk groups in both the training and validation cohorts, with the high-risk group having a significantly worse prognosis (P<0.05). Following further investigation of the immune microenvironment, it was discovered that this risk grouping could serve as a guide for glioma immunotherapy. The activity, invasion and migration capacity, and colony formation ability of U87-MG and LN229 cell lines were drastically reduced after the important gene USP4 in signature was knocked down in cell tests. Overexpression of USP4 in the A172 cell line, on the other hand, greatly improved clonogenesis, activity, invasion and migration. Conclusions: Our research established a foundation for understanding the role of ubiquitination genes in gliomas and identified USP4 as a possible glioma biomarker.

Exosomal PTEN as a Predictive Marker of Aggressive Gliomas.

Background: Liquid biopsies have emerged as convenient alternative diagnostic methods to invasive biopsies, by evaluating disease-specific biomarkers and monitoring the disease risk noninvasively. Phosphatase and tensin homolog deleted in chromosome 10 (PTEN) is a potent tumor suppressor, and its deletion/mutations are common in gliomas. Objective: Evaluate the feasibility of non-invasive detection of PTEN and its downstream genes in serum exosomes of glioma patients. Materials and methods: PTEN, Yes-associated-protein 1 (YAP1), and lysyl oxidase (LOX) transcript expression were monitored through polymerase chain reaction (PCR) in serum exosomes and their paired tumor tissues. The impact of PTEN and its axis genes expression on the overall survival (OS) was monitored. Results: Out of the 106 glioma serum samples evaluated, PTEN was retained/lost in 65.4%/34.6% of the tumor samples while it was retained/lost in 67.1%/32.9% of their paired exosomal fractions. PTEN expression in both tissue and paired exosomal fractions was observed in 48.11% of the samples. Sanger sequencing detected three mutations (Chr10: 89720791(A>G), Chr10:89720749(C>T), and Chr10:89720850(A>G). Both PTEN-responsive downstream genes (YAP1) and LOX axis were upregulated in the PTEN-deficient samples. PTEN loss was associated with poor survival in the glioma patients (hazard ratio (HR) 0.68, confidence interval (CI): 0.35-1.31, P = 0.28). The OS of the exosomal PTEN cohort coincided with the tumor-tissue PTEN devoid group (HR 1.08, CI: 0.49-2.36, P = 0.85). While, old age yielded the worst prognosis; gender, location, and grade were not prognostic of OS in the multivariate analysis. Conclusions: PTEN and its responsive genes YAP1 and LOX can be detected in serum exosomes and can serve as essential tools for the non-invasive evaluation/identification of aggressive gliomas.

Duchenne muscular dystrophy gene expression is an independent prognostic marker for IDH mutant low-grade glioma.

Alterations in the expression of the Duchenne muscular dystrophy (DMD) gene have been associated with the development, progression and survival outcomes of numerous cancers including tumours of the central nervous system. We undertook a detailed bioinformatic analysis of low-grade glioma (LGG) bulk RNAseq data to characterise the association between DMD expression and LGG survival outcomes. High DMD expression was significantly associated with poor survival in LGG with a difference in median overall survival between high and low DMD groups of over 7 years (P = < 0.0001). In a multivariate model, DMD expression remained significant (P = 0.02) and was an independent prognostic marker for LGG. The effect of DMD expression on overall survival was only apparent in isocitrate dehydrogenase (IDH) mutant cases where non-1p/19q co-deleted LGG patients could be further stratified into high/low DMD groups. Patients in the high DMD group had a median overall survival time almost halve that of the low DMD group. The expression of the individual DMD gene products Dp71, Dp71ab and Dp427m were also significantly associated with overall survival in LGG which have differential biological effects relevant to the pathogenesis of LGG. Differential gene expression and pathway analysis identifies dysregulated biological processes relating to ribosome biogenesis, synaptic signalling, neurodevelopment, morphogenesis and immune pathways. Genes spanning almost the entirety of chromosome 1p are upregulated in patients with high overall DMD, Dp71 and Dp427m expression which worsens survival outcomes for these patients. We confirmed dystrophin protein is variably expressed in LGG tumour tissue by immunohistochemistry and, overall, demonstrate that DMD expression has potential utility as an independent prognostic marker which can further stratify IDH mutant LGG to identify those at risk of poor survival. This knowledge may improve risk stratification and management of LGG.

The Pivotal Immunomodulatory and Anti-Inflammatory Effect of Histone-Lysine N-Methyltransferase in the Glioma Microenvironment: Its Biomarker and Therapy Potentials.

Enhancer of zeste homolog 2 (EZH2) is a histone-lysine N-methyltransferase that encrypts a member of the Polycomb group (PcG) family. EZH2 forms a repressive chromatin structure which eventually participates in regulating the development as well as lineage propagation of stem cells and glioma progression. Posttranslational modifications are distinct approaches for the adjusted modification of EZH2 in the development of cancer. The amino acid succession of EZH2 protein makes it appropriate for covalent modifications, like phosphorylation, acetylation, O-GlcNAcylation, methylation, ubiquitination, and sumoylation. The glioma microenvironment is a dynamic component that comprises, besides glioma cells and glioma stem cells, a complex network that comprises diverse cell types like endothelial cells, astrocytes, and microglia as well as stromal components, soluble factors, and the extracellular membrane. EZH2 is well recognized as an essential modulator of cell invasion as well as metastasis in glioma. EZH2 oversecretion was implicated in the malfunction of several fundamental signaling pathways like Wnt/ß-catenin signaling, Ras and NF-κB signaling, PI3K/AKT signaling, ß-adrenergic receptor signaling, and bone morphogenetic protein as well as NOTCH signaling pathways. EZH2 was more secreted in glioblastoma multiforme than in low-grade gliomas as well as extremely secreted in U251 and U87 human glioma cells. Thus, the blockade of EZH2 expression in glioma could be of therapeutic value for patients with glioma. The suppression of EZH2 gene secretion was capable of reversing temozolomide resistance in patients with glioma. EZH2 is a promising therapeutic as well as prognostic biomarker for the treatment of glioma.

A Disintegrin and Metalloproteinase (ADAM) Family: Their Significance in Malignant Tumors of the Central Nervous System (CNS).

Despite the considerable advances in diagnostic methods in medicine, central nervous system (CNS) tumors, particularly the most common ones-gliomas-remain incurable, with similar incidence rates and mortality. A growing body of literature has revealed that degradation of the extracellular matrix by matrix metalloproteinases (MMPs) might be involved in the pathogenesis of CNS tumors. However, the subfamily of MMPs, known as disintegrin and metalloproteinase (ADAM) proteins are unique due to both adhesive and proteolytic activities. The objective of our review is to present the role of ADAMs in CNS tumors, particularly their involvement in the development of malignant gliomas. Moreover, we focus on the diagnostic and prognostic significance of selected ADAMs in patients with these neoplasms. It has been proven that ADAM12, ADAMTS4 and 5 are implicated in the proliferation and invasion of glioma cells. In addition, ADAM8 and ADAM19 are correlated with the invasive activity of glioma cells and unfavorable survival, while ADAM9, -10 and -17 are associated with tumor grade and histological type of gliomas and can be used as prognostic factors. In conclusion, several ADAMs might serve as potential diagnostic and prognostic biomarkers as well as therapeutic targets for malignant CNS tumors. However, future research on ADAMs biology should be performed to elucidate new strategies for tumor diagnosis and treatment of patients with these malignancies.

Upregulation of the APOBEC3 Family Is Associated with a Poor Prognosis and Influences Treatment Response to Raf Inhibitors in Low Grade Glioma.

Apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3 (APOBEC3) has been identified as a group of enzymes that catalyze cytosine deamination in single-stranded (ss) DNA to form uracil, causing somatic mutations in some cancers. We analyzed the APOBEC3 family in 33 TCGA cancer types and the results indicated that APOBEC3s are upregulated in multiple cancers and strongly correlate with prognosis, particularly in low grade glioma (LGG). Then we constructed a prognostic model based on family expression in LGG where the APOBEC3 family signature is an accurate predictive model (AUC of 0.85). Gene mutation, copy number variation (CNV), and a differential gene expression (DEG) analysis were performed in different risk groups, and the weighted gene co-expression network analysis (WGCNA) was employed to clarify the role of various members in LGG; CIBERSORT algorithm was deployed to evaluate the landscape of LGG immune infiltration. We found that upregulation of the APOBEC3 family expression can strengthen Ras/MAPK signaling pathway, promote tumor progression, and ultimately reduce the treatment benefits of Raf inhibitors. Moreover, the APOBEC3 family was shown to enhance the immune response mediated by myeloid cells and interferon gamma, as well as PD-L1 and PD-L2 expression, implying that they have immunotherapy potential. Therefore, the APOBEC3 signature enables an efficient assessment of LGG patient survival outcomes and expansion of clinical benefits by selecting appropriate individualized treatment strategies.

Identification of autophagic target RAB13 with small-molecule inhibitor in low-grade glioma via integrated multi-omics approaches coupled with virtual screening of traditional Chinese medicine databases.

OBJECTIVES: Autophagy, a highly conserved lysosomal degradation process in eukaryotic cells, has been widely reported closely related to the progression of many types of human cancers, including LGG; however, the intricate relationship between autophagy and LGG remains to be clarified. MATERIALS AND METHODS: Multi-omics methods were used to integrate omics data to determine potential autophagy regulators in LGG. The expression of ZFP36L2 and RAB13 in SW1088 cells was experimentally manipulated using cDNAs and small interfering RNAs (siRNA). RT-qPCR detects RNAi gene knockout and cDNA overexpression efficiency. The expression levels of proteins in SW1088 cells were evaluated using Western blot analysis and immunofluorescence analysis. Homology modelling and molecular docking were used to identify compounds from Multi-Traditional Chinese Medicine (TCM) Databases. The apoptosis ratios were determined by flow cytometry analysis of Annexin-V/PI double staining. We detect the number of autophagosomes by GFP-MRFP-LC3 plasmid transfection to verify the process of autophagy flow. RESULTS: We integrated various omics data from LGG, including EXP, MET and CNA data, with the SNF method and the LASSO algorithm, and identified ZFP36L2 and RAB13 as positive regulators of autophagy, which are closely related to the core autophagy regulators. Both transcription level and protein expression level of the four autophagy regulators, including ULK1, FIP200, ATG16L1 and ATG2B, and LC3 puncta were increased by ZFP36L2 and RAB13 overexpression. In addition, RAB13 participates in autophagy through ATG2B, FIP200, ULK1, ATG16L1 and Beclin-1. Finally, we screened multi-TCM databases and identified gallic acid as a novel potential RAB13 inhibitor, which was confirmed to negatively regulate autophagy as well as to induce cell death in SW1088 cells. CONCLUSION: Our study identified the key autophagic regulators ZFP36L2 and Rab13 in LGG progression, and demonstrated that gallic acid is a small molecular inhibitor of RAB13, which negatively regulates autophagy and provides a possible small molecular medicine for the subsequent treatment of LGG.

Predicting prognosis and IDH mutation status for patients with lower-grade gliomas using whole slide images.

We developed end-to-end deep learning models using whole slide images of adults diagnosed with diffusely infiltrating, World Health Organization (WHO) grade 2 gliomas to predict prognosis and the mutation status of a somatic biomarker, isocitrate dehydrogenase (IDH) 1/2. The models, which utilize ResNet-18 as a backbone, were developed and validated on 296 patients from The Cancer Genome Atlas (TCGA) database. To account for the small sample size, repeated random train/test splits were performed for hyperparameter tuning, and the out-of-sample predictions were pooled for evaluation. Our models achieved a concordance- (C-) index of 0.715 (95% CI: 0.569, 0.830) for predicting prognosis and an area under the curve (AUC) of 0.667 (0.532, 0.784) for predicting IDH mutations. When combined with additional clinical information, the performance metrics increased to 0.784 (95% CI: 0.655, 0.880) and 0.739 (95% CI: 0.613, 0.856), respectively. When evaluated on the WHO grade 3 gliomas from the TCGA dataset, which were not used for training, our models predicted survival with a C-index of 0.654 (95% CI: 0.537, 0.768) and IDH mutations with an AUC of 0.814 (95% CI: 0.721, 0.897). If validated in a prospective study, our method could potentially assist clinicians in managing and treating patients with diffusely infiltrating gliomas.

TOP2B Enzymatic Activity on Promoters and Introns Modulates Multiple Oncogenes in Human Gliomas.

PURPOSE: The epigenetic mechanisms involved in transcriptional regulation leading to malignant phenotype in gliomas remains poorly understood. Topoisomerase IIB (TOP2B), an enzyme that decoils and releases torsional forces in DNA, is overexpressed in a subset of gliomas. Therefore, we investigated its role in epigenetic regulation in these tumors. EXPERIMENTAL DESIGN: To investigate the role of TOP2B in epigenetic regulation in gliomas, we performed paired chromatin immunoprecipitation sequencing for TOP2B and RNA-sequencing analysis of glioma cell lines with and without TOP2B inhibition and in human glioma specimens. These experiments were complemented with assay for transposase-accessible chromatin using sequencing, gene silencing, and mouse xenograft experiments to investigate the function of TOP2B and its role in glioma phenotypes. RESULTS: We discovered that TOP2B modulates transcription of multiple oncogenes in human gliomas. TOP2B regulated transcription only at sites where it was enzymatically active, but not at all native binding sites. In particular, TOP2B activity localized in enhancers, promoters, and introns of PDGFRA and MYC, facilitating their expression. TOP2B levels and genomic localization was associated with PDGFRA and MYC expression across glioma specimens, which was not seen in nontumoral human brain tissue. In vivo, TOP2B knockdown of human glioma intracranial implants prolonged survival and downregulated PDGFRA. CONCLUSIONS: Our results indicate that TOP2B activity exerts a pleiotropic role in transcriptional regulation of oncogenes in a subset of gliomas promoting a proliferative phenotype.

Kynurenine Monooxygenase Expression and Activity in Human Astrocytomas.

Glioblastoma multiforme (GBM) is the most common and aggressive primary brain tumor. The enzyme indoleamine-2,3-dioxygenase (IDO), which participates in the rate-limiting step of tryptophan catabolism through the kynurenine pathway (KP), is associated with poor prognosis in patients with GBM. The metabolites produced after tryptophan oxidation have immunomodulatory properties that can support the immunosuppressor environment. In this study, mRNA expression, protein expression, and activity of the enzyme kynurenine monooxygenase (KMO) were analyzed in GBM cell lines (A172, LN-18, U87, U373) and patient-derived astrocytoma samples. KMO mRNA expression was assessed by real-time RT-qPCR, KMO protein expression was evaluated by flow cytometry and immunofluorescence, and KMO activity was determined by quantifying 3-hydroxykynurenine by HPLC. Heterogenous patterns of both KMO expression and activity were observed among the GBM cell lines, with the A172 cell line showing the highest KMO expression and activity. Higher KMO mRNA expression was observed in glioma samples than in patients diagnosed with only a neurological disease; high KMO mRNA expression was also observed when using samples from patients with GBM in the TCGA program. The KMO protein expression was localized in GFAP+ cells in tumor tissue. These results suggest that KMO is a relevant target to be explored in glioma since it might play a role in supporting tumor metabolism and immune suppression.

Evaluating Mechanisms of IDH1 Regulation through Site-Specific Acetylation Mimics.

Isocitrate dehydrogenase (IDH1) catalyzes the reversible NADP+-dependent oxidation of isocitrate to α-ketoglutarate (αKG). IDH1 mutations, primarily R132H, drive > 80% of low-grade gliomas and secondary glioblastomas and facilitate the NADPH-dependent reduction of αKG to the oncometabolite D-2-hydroxyglutarate (D2HG). While the biochemical features of human WT and mutant IDH1 catalysis have been well-established, considerably less is known about mechanisms of regulation. Proteomics studies have identified lysine acetylation in WT IDH1, indicating post-translational regulation. Here, we generated lysine to glutamine acetylation mimic mutants in IDH1 to evaluate the effects on activity. We show that mimicking lysine acetylation decreased the catalytic efficiency of WT IDH1, with less severe catalytic consequences for R132H IDH1.

From Laboratory Studies to Clinical Trials: Temozolomide Use in IDH-Mutant Gliomas.

In this review, we discuss the use of the alkylating agent temozolomide (TMZ) in the treatment of IDH-mutant gliomas. We describe the challenges associated with TMZ in clinical (drug resistance and tumor recurrence) and preclinical settings (variabilities associated with in vitro models) in treating IDH-mutant glioma. Lastly, we summarize the emerging therapeutic targets that can potentially be used in combination with TMZ.

Targeting RTK-PI3K-mTOR Axis in Gliomas: An Update.

Gliomas are the most common and challenging malignancies of the central nervous system (CNS), due to their infiltrative nature, tendency to recurrence, and poor response to treatments. Indeed, despite the advances in neurosurgical techniques and in radiation therapy, the modest effects of therapy are still challenging. Moreover, tumor recurrence is associated with the onset of therapy resistance; it is therefore critical to identify effective and well-tolerated pharmacological approaches capable of inducing durable responses in the appropriate patient groups. Molecular alterations of the RTK/PI3K/Akt/mTOR signaling pathway are typical hallmarks of glioma, and several clinical trials targeting one or more players of this axis have been launched, showing disappointing results so far, due to the scarce BBB permeability of certain compounds or to the occurrence of resistance/tolerance mechanisms. However, as RTK/PI3K/mTOR is one of the pivotal pathways regulating cell growth and survival in cancer biology, targeting still remains a strong rationale for developing strategies against gliomas. Future rigorous clinical studies, aimed at addressing the tumor heterogeneity, the interaction with the microenvironment, as well as diverse posology adjustments, are needed-which might unravel the therapeutic efficacy and response prediction of an RTK/PI3K/mTOR-based approach.

Radiological model based on the standard magnetic resonance sequences for detecting methylguanine methyltransferase methylation in glioma using texture analysis.

This study aims to build a radiological model based on standard MR sequences for detecting methylguanine methyltransferase (MGMT) methylation in gliomas using texture analysis. A retrospective cross-sectional study was undertaken in a cohort of 53 glioma patients who underwent standard preoperative magnetic resonance (MR) imaging. Conventional visual radiographic features and clinical factors were compared between MGMT promoter methylated and unmethylated groups. Texture analysis extracted the top five most powerful texture features of MR images in each sequence quantitatively for detecting the MGMT promoter methylation status. The radiomic signature (Radscore) was generated by a linear combination of the five features and estimates in each sequence. The combined model based on each Radscore was established using multivariate logistic regression analysis. A receiver operating characteristic (ROC) curve, nomogram, calibration, and decision curve analysis (DCA) were used to evaluate the performance of the model. No significant differences were observed in any of the visual radiographic features or clinical factors between different MGMT methylated statuses. The top five most powerful features were selected from a total of 396 texture features of T1, contrast-enhanced T1, T2, and T2 FLAIR. Each sequence's Radscore can distinguish MGMT methylated status. A combined model based on Radscores showed differentiation between methylated MGMT and unmethylated MGMT both in the glioblastoma (GBM) dataset as well as the dataset for all other gliomas. The area under the ROC curve values for the combined model was 0.818, with 90.5% sensitivity and 72.7% specificity, in the GBM dataset, and 0.833, with 70.2% sensitivity and 90.6% specificity, in the overall gliomas dataset. Nomogram, calibration, and DCA also validated the performance of the combined model. The combined model based on texture features could be considered as a noninvasive imaging marker for detecting MGMT methylation status in glioma.

PDIA5 is Correlated With Immune Infiltration and Predicts Poor Prognosis in Gliomas.

Gliomas are the most common and lethal primary malignant tumor of the brain. Routine treatment including surgical resection, chemotherapy, and radiotherapy produced limited therapeutic effect, while immunotherapy targeting the glioma microenvironment has offered a novel therapeutic option. PDIA5 protein is the member of PDI family, which is highly expressed in glioma and participates in glioma progression. Based on large-scale bioinformatics analysis, we discovered that PDIA5 expression level is upregulated in aggressive gliomas, with high PDIA5 expression predicting poor clinical outcomes. We also observed positive correlation between PDIA5 and immune infiltrating cells, immune related pathways, inflammatory activities, and other immune checkpoint members. Patients with high PDIA5 high-expression benefited from immunotherapies. Additionally, immunohistochemistry revealed that PDIA5 and macrophage biomarker CD68 were upregulated in high-grade gliomas, and patients with low PDIA5 level experienced favorable outcomes among 33 glioma patients. Single cell RNA sequencing exhibited that PDIA5 was in high level presenting in neoplastic cells and macrophages. Cell transfection and co-culture of glioma cells and macrophages revealed that PDIA5 in tumor cells mediated macrophages exhausting. Altogether, our findings indicate that PDIA5 overexpression is associated with immune infiltration in gliomas, and may be a promising therapeutic target for glioma immunotherapy.

Identification and characterization of a novel mutant isocitrate dehydrogenase 1 inhibitor for glioma treatment.

Isocitrate dehydrogenase 1 (IDH1) mutant R132H, promoting the oncometabolite D-2-hydroxyglutarate (D2HG), is a driver mutation and an emerging therapeutic target in glioma. This study identified a novel mutant IDH1 inhibitor, WM17, by virtual screening and enzymatic confirmation. It could bind to and increase mutant IDH1 protein's thermostability in both endogenous heterozygous cells and exogenous overexpressed cells. Consequently, WM17 reversed the accumulation of D2HG and histone hypermethylation in IDH1 mutated cells. Finally, we concluded that WM17 significantly inhibited cell migration in IDH1 mutated glioma cells, although it has no apparent effect on cell proliferation. Further studies are guaranteed toward the development of WM17 as a therapeutic agent for IDH1 mutated glioma.

Widespread overexpression from the four DNA hypermethylated HOX clusters in aggressive (IDHwt) glioma is associated with H3K27me3 depletion and alternative promoter usage.

In human, the 39 coding HOX genes and 18 referenced noncoding antisense transcripts are arranged in four genomic clusters named HOXA, B, C, and D. This highly conserved family belongs to the homeobox class of genes that encode transcription factors required for normal development. Therefore, HOX gene deregulation might contribute to the development of many cancer types. Here, we study HOX gene deregulation in adult glioma, a common type of primary brain tumor. We performed extensive molecular analysis of tumor samples, classified according to their isocitrate dehydrogenase (IDH1) gene mutation status, and of glioma stem cells. We found widespread expression of sense and antisense HOX transcripts only in aggressive (IDHwt) glioma samples, although the four HOX clusters displayed DNA hypermethylation. Integrative analysis of expression, DNA methylation, and histone modification signatures along the clusters revealed that HOX gene upregulation relies on canonical and alternative bivalent CpG island promoters that escape hypermethylation. H3K27me3 loss at these promoters emerges as the main cause of widespread HOX gene upregulation in IDHwt glioma cell lines and tumors. Our study provides the first comprehensive description of the epigenetic changes at HOX clusters and their contribution to the transcriptional changes observed in adult glioma. It also identified putative 'master' HOX proteins that might contribute to the tumorigenic potential of glioma stem cells.

MYC-mediated upregulation of PNO1 promotes glioma tumorigenesis by activating THBS1/FAK/Akt signaling.

PNO1 has been reported to be involved in tumorigenesis, however, its role in glioma remains unexplored. In the present study, PNO1 expression in glioma from on-line databases, cDNA, and tissue microarrays was upregulated and associated with poor prognosis. PNO1 knockdown inhibits tumor cell growth and invasion both in vitro and in vivo; whereas PNO1 overexpression promoted cell proliferation and invasion in vitro. Notably, PNO1 interacted with THBS1 and the promotion of glioma by PNO1 overexpression could be attenuated or even reversed by simultaneously silencing THBS1. Functionally, PNO1 was involved in activation of FAK/Akt pathway. Moreover, overexpressing MYC increased PNO1 promoter activity. MYC knockdown decreased PNO1 and THBS1 expression, while inhibited cell proliferation and invasion. In conclusion, MYC-mediated upregulation of PNO1 contributes to glioma progression by activating THBS1/FAK/Akt signaling. PNO1 was reported to be a tumor promotor in the development and progression of glioma and may act as a candidate of therapeutic target in glioma treatment.

Comprehensive analysis of PLOD family members in low-grade gliomas using bioinformatics methods.

Low-grade gliomas (LGGs) is a primary invasive brain tumor that grows slowly but is incurable and eventually develops into high malignant glioma. Novel biomarkers for the tumorigenesis and lifetime of LGG are critically demanded to be investigated. In this study, the expression levels of procollagen-lysine, 2-oxoglutarate 5-dioxygenases (PLODs) were analyzed by ONCOMINE, HPA and GEPIA. The GEPIA online platform was applied to evaluate the interrelation between PLODs and survival index in LGG. Furthermore, functions of PLODs and co-expression genes were inspected by the DAVID. Moreover, we used TIMER, cBioportal, GeneMINIA and NetworkAnalyst analysis to reveal the mechanism of PLODs in LGG. We found that expression levels of each PLOD family members were up-regulated in patients with LGG. Higher expression of PLODs was closely related to shorter disease-free survival (DFS) and overall survival (OS). The findings showed that LGG cases with or without alterations were significantly correlated with the OS and DFS. The mechanism of PLODs in LGG may be involved in response to hypoxia, oxidoreductase activity, Lysine degradation and immune cell infiltration. In general, this research has investigated the values of PLODs in LGG, which could serve as biomarkers for diagnosis, prognosis and potential therapeutic targets of LGG patients.

Antioxidative effect of DJ-1 is enhanced in NG108-15 cells by DPMQ-induced copper influx.

Disruption of copper homeostasis is closely involved in neurodegenerative disorders. This study examined whether a hybrid copper-binding compound, (E)-2-(4-(dimethylamino)phenylimino)methyl)quinolin-8-ol (DPMQ), is able to protect NG108-15 cells against oxidative stress. We found that treatment of cells with rotenone or hydrogen peroxide increased cellular oxidative stress and resulted in mitochondrial dysfunction and apoptosis. The cellular levels of Nrf2 and the Cu2+ chaperone DJ-1 were also decreased. These oxidative detrimental effects were all inhibited when cells were cotreated with DPMQ. DPMQ increased cellular Cu2+ content, DJ-1 protein level, superoxide dismutase (SOD) activity, and Nrf2 nuclear translocation under basal state. The activity of SOD decreased under redox imbalance and this decrease was blocked by DPMQ treatment, while the protein level of SOD1 remained unaltered regardless of the oxidative stress and DPMQ treatment. Using endogenous proteins, coimmunoprecipitation showed that DJ-1 bound with SOD1 and Nrf2 individually. The amount of Nrf2, bound to DJ-1, consistently reflected its cellular level, while the amount of SOD1, bound to DJ-1, was potentiated by DPMQ, being greater in the basal state than under redox imbalance. Simultaneous inclusion of nonpermeable Cu2+ chelator tetrathiomolybdate or triethylenetetramine during DPMQ treatment blocked all aforementioned effects of DPMQ, showing that the dependency of the effect of DPMQ on extracellular Cu2+. In addition, silencing of DJ-1 blocked the protection of DPMQ against oxidative stress. Taken all together, our results suggest that DPMQ stabilizes DJ-1 in a Cu2+-dependent manner, which then brings about SOD1 activation and Nrf2 nuclear translocation; these together alleviate cellular oxidative stress.