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Background: Determination of H3 K27M mutation in diffuse midline glioma (DMG) is key for prognostic assessment and stratifying patient subgroups for clinical trials. MRI can noninvasively depict morphological and metabolic characteristics of H3 K27M mutant DMG., Purpose: This study aimed to develop a deep learning (DL) approach to noninvasively predict H3 K27M mutation in DMG using T2-weighted images., Study Type: Retrospective and prospective., Population: For diffuse midline brain gliomas, 341 patients from Center-1 (27 ± 19 years, 184 males), 42 patients from Center-2 (33 ± 19 years, 27 males) and 35 patients (37 ± 18 years, 24 males). For diffuse spinal cord gliomas, 133 patients from Center-1 (30 ± 15 years, 80 males)., Field Strength/sequence: 5T and 3T, T2-weighted turbo spin echo imaging., Assessment: Conventional radiological features were independently reviewed by two neuroradiologists. H3 K27M status was determined by histopathological examination. The Dice coefficient was used to evaluate segmentation performance. Classification performance was evaluated using accuracy, sensitivity, specificity, and area under the curve., Statistical Tests: Pearson's Chi-squared test, Fisher's exact test, two-sample Student's t-test and Mann-Whitney U test. A two-sided P value <0.05 was considered statistically significant., Results: In the testing cohort, Dice coefficients of tumor segmentation using DL were 0.87 for diffuse midline brain and 0.81 for spinal cord gliomas. In the internal prospective testing dataset, the predictive accuracies, sensitivities, and specificities of H3 K27M mutation status were 92.1%, 98.2%, 82.9% in diffuse midline brain gliomas and 85.4%, 88.9%, 82.6% in spinal cord gliomas. Furthermore, this study showed that the performance generalizes to external institutions, with predictive accuracies of 85.7%-90.5%, sensitivities of 90.9%-96.0%, and specificities of 82.4%-83.3%., Data Conclusion: In this study, an automatic DL framework was developed and validated for accurately predicting H3 K27M mutation using T2-weighted images, which could contribute to the noninvasive determination of H3 K27M status for clinical decision-making., Evidence Level: 2 Technical Efficacy: Stage 2., (© 2023 International Society for Magnetic Resonance in Medicine.)

Abstract: The prognosis for diffusely infiltrating gliomas at World Health Organization (WHO) grade 2-4 remains dismal due to their heterogeneity. The rapid development of genome-wide molecular-profiling-associated studies has greatly promoted the accuracy of glioma classification. Thus, the latest version of the WHO classification of the central nervous system tumors published in 2021 has incorporated more molecular biomarkers together with histological features for the diagnosis of gliomas. Advanced usage of molecular pathology in clinical diagnostic practice provides also new opportunities for the therapy of patients with glioma, including surgery, radiotherapy and chemotherapy, targeted therapy, immunotherapy, and more precision clinical trials. Herein, we highlight the updates in the classification of gliomas according to the latest WHO guidelines and summarize the clinically relevant molecular markers by focusing on their applications in clinical practice. We also review the advances in molecular features of gliomas, which can facilitate the development of glioma therapies, thereby discussing the challenges and future directions of molecular pathology toward precision medicine for patients with glioma., (Copyright © 2023 The Chinese Medical Association, produced by Wolters Kluwer, Inc. under the CC-BY-NC-ND license.)

Glioma is the most common lethal tumor of the human brain. The median survival of patients with primary World Health Organization grade IV glioma is only 14.6 months. The World Health Organization classification of tumors of the central nervous system categorized gliomas into lower-grade gliomas and glioblastomas. Unlike primary glioblastoma that usually develop de novo in the elderly, secondary glioblastoma enriched with an isocitrate dehydrogenase mutant typically progresses from lower-grade glioma within 5-10 years from the time of diagnosis. Based on various evolutional trajectories brought on by clonal and subclonal alterations, the evolution patterns of glioma vary according to different theories. Some important features distinguish the normal brain from other tissues, e.g., the composition of the microenvironment around the tumor cells, the presence of the blood-brain barrier, and others. The underlying mechanism of glioma recurrence and evolution patterns of glioma are different from those of other types of cancer. Several studies correlated tumor recurrence with tumor heterogeneity and the immune microenvironment. However, the detailed reasons for the progression and recurrence of glioma remain controversial. In this review, we introduce the different mechanisms involved in glioma progression, including tumor heterogeneity, the tumor microenvironment and drug resistance, and their pre-clinical implements in clinical trials. This review aimed to provide new insights into further clinical strategies for the treatment of patients with recurrent and secondary glioma., (© 2021. Higher Education Press.)

To follow the revision of the fourth edition of WHO classification and the recent progress on the management of diffuse gliomas, the joint guideline committee of Chinese Glioma Cooperative Group (CGCG), Society for Neuro-Oncology of China (SNO-China) and Chinese Brain Cancer Association (CBCA) updated the clinical practice guideline. It provides recommendations for diagnostic and management decisions, and for limiting unnecessary treatments and cost. The recommendations focus on molecular and pathological diagnostics, and the main treatment modalities of surgery, radiotherapy, and chemotherapy. In this guideline, we also integrated the results of some clinical trials of immune therapies and target therapies, which we think are ongoing future directions. The guideline should serve as an application for all professionals involved in the management of patients with adult diffuse glioma and also a source of knowledge for insurance companies and other institutions involved in the cost regulation of cancer care in China and other countries., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Objective: O6methylguanine-DNA methyltransferase ( MGMT ) promoter methylation is a biomarker widely used to predict the sensitivity of IDH -wildtype glioblastoma to temozolomide therapy. Given that the IDH status has critical effects on the survival and epigenetic features of glioblastoma, we aimed to assess the role of MGMT promoter methylation in IDH -mutant glioblastoma., Methods: This study included 187 IDH -mutant glioblastomas and used 173 IDH -wildtype glioblastomas for comparison. Kaplan-Meier curves and multivariate Cox regression were used to study the predictive effects., Results: Compared with IDH -wildtype glioblastomas, IDH -mutant glioblastomas showed significantly higher ( P < 0.0001) MGMT promoter methylation. We demonstrated that MGMT promoter methylation status, as determined by a high cutoff value (≥30%) in pyrosequencing, could be used to significantly stratify the survival of 50 IDH -mutant glioblastomas receiving temozolomide therapy (cohort A); this result was validated in another cohort of 25 IDH -mutant glioblastomas (cohort B). The median progression-free survival and median overall survival in cohort A were 9.33 and 13.76 months for unmethylated cases, and 18.37 and 41.61 months for methylated cases, and in cohort B were 6.97 and 9.10 months for unmethylated cases, and 23.40 and 26.40 months for methylated cases. In addition, we confirmed that the MGMT promoter methylation was significantly ( P = 0.0001) correlated with longer OS in IDH -mutant patients with GBM, independently of age, gender distribution, tumor type (primary or recurrent/secondary), and the extent of resection., Conclusions: MGMT promoter methylation has predictive value in IDH -mutant glioblastoma, but its cutoff value should be higher than that for IDH -wildtype glioblastoma., Competing Interests: Conflict of interest statement No potential conflicts of interest are disclosed., (Copyright: © 2021, Cancer Biology & Medicine.)

This study aimed to identify the optimal radiomic machine-learning classifier for differentiating glioblastoma (GBM) from solitary brain metastases (MET) preoperatively. Four hundred and twelve patients with solitary brain tumors (242 GBM and 170 solitary brain MET) were divided into training (n = 227) and test (n = 185) cohorts. Radiomic features extraction was performed with PyRadiomics software. In the training cohort, twelve feature selection methods and seven classification methods were evaluated to construct favorable radiomic machine-learning classifiers. The performance of the classifiers was evaluated using the mean area under the curve (AUC) and relative standard deviation in percentile (RSD). In the training cohort, thirteen classifiers had favorable predictive performances (AUC≥0.95 and RSD ≤6). In the test cohort, receiver operating characteristic (ROC) curve analysis revealed that support vector machines (SVM) + least absolute shrinkage and selection operator (LASSO) (AUC, 0.90) classifiers had the highest prediction efficacy. Furthermore, the clinical performance of the best classifier was superior to neuroradiologists in accuracy, sensitivity, and specificity. In conclusion, employing radiomic machine-learning technology could help neuroradiologist in differentiating GBM from solitary brain MET preoperatively., (Copyright © 2019. Published by Elsevier B.V.)

The mesenchymal (MES) subtype of glioblastoma (GBM) indicated a more malignant phenotype and worse prognosis compared with their proneural (PN) counterpart. The plasticity between PN and MES transcriptome signatures provided an approach for clinical intervention. However, few miRNAs have been identified to participate in the shift between subtypes. Here, we utilized transcriptomic data and experimental evidences to prove that miR-181d was a novel regulator of NFκB signaling pathway by directly repressing MALT1, leading to induced PN markers and reduced MES genes. Functionally, ectopic expression of miR-181d suppressed GBM cell proliferation, colony formation and anchor-independent growth, as well as migration, invasion and tube formation. Moreover, miR-181d overexpression increased radio- and chemo-sensitivity for GBM cells. Rescue of MALT1 could partially reverse the effects of miR-181d in GBM malignant behaviors. Clinically, miR-181d could serve as a prognostic indicator for GBM patients. Taken together, we concluded that loss of miR-181d contributes to aggressive biological processes associated with MES phenotype via NFκB signaling, which broaden our insights into the underlying mechanisms in subtype transition and miRNA-based tailored medicine for GBM management., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Glioblastoma accounts for more than half of diffuse gliomas. The prognosis of patients with glioblastoma remains poor despite comprehensive and intensive treatments. Furthermore, the clinical significance of molecular parameters and routinely available clinical variables for the prognosis prediction of glioblastomas remains limited. The authors describe a novel model may help in prognosis prediction and clinical management of glioblastoma patients. We performed a recursive partitioning analysis to generate three independent prognostic classes of 103 glioblastomas patients from TCGA dataset. Class I (MGMT promoter methylated, age <58), class II (MGMT promoter methylation, age ≥58; MGMT promoter unmethylation, age <54, KPS ≥70; MGMT promoter unmethylation, age >59, KPS ≥70), class III (MGMT promoter unmethylation, age 54-58, KPS ≥70; MGMT promoter unmethylation, KPS <70). Age, KPS and MGMT promoter methylation were the most significant prognostic factors for overall survival. The results were validated in CGGA dataset.This was the first study to combine various molecular parameters and clinical factors into recursive partitioning analysis to predict the prognosis of patients with glioblastomas. We included MGMT promoter methylation in our study, which could give better suggestion to patients for their chemotherapy. This clinical study will serve as the backbone for the future incorporation of molecular prognostic markers currently in development. Thus, our recursive partitioning analysis model for glioblastomas may aid in clinical prognosis evaluation.

The goal of this work was to explore the most effective miRNAs affecting glioblastoma multiforme (GBM) phenotype transition and malignant progression. We annotated 491 TCGA samples' miRNA expression profiles according to their mRNA-based subtypes and found that the mesenchymal tumors had significantly decreased miR-181 family expression compared with the other three subtypes while the proneural subtype harbored extremely high miR-181 family expression. Patients with high miR-181 family expression had longer overall survival (p = 0.0031). We also confirmed that NF-κB-targeting genes and the EMT (epithelial-mesenchymal transition) pathway were inversely correlated with miR-181 family expression and that the entire miR-181 family inhibited glioma cell invasion and proliferation; of these, miR-181b was the most effective suppressor. Furthermore, miR-181b was validated to suppress EMT by targeting KPNA4 and was associated with survival outcome in the TCGA and CGGA datasets and in another independent cohort. The EMT-inhibitory effect of miR-181b was lost after KPNA4 expression was restored. We also identified the antitumorigenic activity of miR-181b in vitro and in vivo. Our results showed that miR-181 family expression was closely correlated with TCGA subtypes and patients' overall survival, indicating that miR-181b, a tumor-suppressive miRNA, could be a novel therapeutic candidate for treating gliomas.

Purpose: Seizures are a common manifestation of many diseases and play an important role in the clinical presentation and quality of life (QOL) in patients with gliomas. The purpose of the present study was to investigate the possible correlation between tumor-related seizures and clinicopathological factors that influence preoperative seizure characteristics and relevant survival outcomes., Methods: We retrospectively investigated the correlation of preoperative seizures with clinicopathological factors and prognosis in a cohort of 198 Chinese patients with anaplastic gliomas. Univariate and multivariate logistic regression analyses were used to identify factors associated with preoperative seizures. Survival function curves were calculated using the Kaplan-Meier method., Results: Of the 198 patients, 68 (34.3%) patients had preoperative seizures. Among the patients with seizures, 26 (38.2%) had generalized seizures, 38 (55.9%) had simple partial seizures, and four (5.9%) complex seizures. There was a higher proportion of epidermal growth factor receptor (EGFR) amplification, frontal lobe involvement, left cerebral hemisphere involvement, and lower Ki-67 expression in patients with preoperative seizures in both univariate and multivariate analyses. Patients with preoperative seizures had a longer overall survival (OS) time compared with those without (median: 1924 days vs. 923 days, P=0.048)., Conclusion: The current study updates existing information on tumor-related seizures and clinicopathological factors in anaplastic gliomas, and suggests two putative biomarkers for preoperative seizures; Ki-67 expression and EGFR amplification. These factors may provide insights for developing effective treatment strategies aimed at prolonging patient survival., (Copyright © 2014 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)

Although temozolomide (TMZ) replaced nitrosoureas as the standard initial chemotherapy for glioblastoma (GBM), no studies have compared TMZ with nimustine (ACNU), a nitrosourea agent widely used in central Europe and most Asian regions. One hundred thirty-five patients with GBM who underwent extensive tumor resection in our institution received both radiation and chemotherapy as initial treatment, 34 received TMZ and 101 ACNU-based (ACNU plus teniposide or cisplatin) chemotherapy. Efficacy analysis included overall survival (OS) and progression-free survival (PFS). The following prognostic factors were taken into account: age, performance status, extent of resection, and O(6)-methylguanine-DNA-methyltransferase (MGMT) gene status. The median OS was superior in the TMZ versus the ACNU group (p = 0.011), although MGMT gene silencing, which is associated with a striking survival benefit from alkylating agents, was more frequent in the ACNU group. In multivariate Cox analysis adjusting for the common prognostic factors, TMZ chemotherapy independently predicted a favorable outcome (p = 0.002 for OS, hazard ratio [HR], 0.45; p = 0.011 for PFS, HR, 0.56). Given that >40 % of patients in ACNU group did not receive the intensive chemotherapy cycles because of severe hematological and nonhematological toxicity, we performed a further subanalysis for patients who received at least 4 cycles of chemotherapy. Although a modest improvement in survival occurred in this ACNU subgroup, the efficacy was still inferior to that in the TMZ cohort. Our data suggest that the survival benefit of TMZ therapy is superior to that of an ACNU-based regimen in patients with extensive tumor resection, also shows greater tolerability.

In order to more thoroughly analyze aberrant DNA methylation in glioma, we applied a large cohort methylation microarray including 119 glioma samples. Six genes, ADCY1, KAZALD1, KLF4, SLMAP, TETRAN and TP53INP1, were screened out through significance analysis of microarray (SAM), survival Cox-regression and certain other pre-set conditions. We focused on the KAZALD1 oncogene. KAZALD1, also known as IGFBP-rP10, belongs to the IGFBP family. We found that KAZALD1 was hypomethylated in high-grade glioma (anaplastic gliomas and glioblastomas) compared to low-grade glioma (astrocytoma, oligodendrocytoma and oligoastrocytoma) using methylation microarrays (p<0.001). Immunohistochemistry (IHC) of 91 glioma samples showed that the KAZALD1 expression scores of high-grade glioma samples were higher compared to the scores of low-grade gliomas (p<0.001). In high-grade gliomas, overall survival (OS) was shorter for patients with KAZALD1 hypomethylation or overexpression compared to those without. Decreased KAZALD1 expression in glioma inhibited cell proliferation and invasion both in vitro and in vivo. On the basis of these observations and the results from subset analysis, it is reasonable to conclude that KAZALD1 promoter hypomethylation is an important prognostic biomarker in glioma. KAZALD1 promotes glioma malignant progression through invasion and proliferation.

Background: Dysregulated zinc transport has been observed in many cancers. However, the status of zinc homeostasis and the expression profile of zinc transporters in brain and brain tumors have not been reported., Methods: The gene profiles of 14 zinc importers (ZIPs) and 10 zinc exporters (ZnTs) in patients with glioma were studied by investigating the association between the zinc transporters and brain tumor characteristics (tumor grade and overall survival time). Three independent cohorts were analyzed to cross-validate the findings: the Chinese Glioma Genome Atlas (CGCA) cohort (n = 186), the US National Cancer Institute Repository for Molecular Brain Neoplasia Data (REMBRANDT) cohort (n = 335), and The University of Texas (UT) cohort (n = 34)., Results: The expression of ZIP3, 4, 8, 14, ZnT5, 6, and 7 were increased, and the expression of ZnT10 was decreased in grade IV gliomas, compared with grade II gliomas. Among all 24 zinc transporters, ZIP4 is most significantly associated with tumor grade and overall survival; this finding is consistent across 2 independent cohorts (CGCA and REMBRANDT) and is partially validated by the third cohort (UT). High ZIP4 expression was significantly associated with higher grade of gliomas and shorter overall survival (hazard ratio = 1.61, 95% confidence interval = 1.02-2.53, P = .040 in CGCA cohort; hazard ratio = 1.32, 95% confidence interval = 1.08-1.61, P = .007 in REMBRANDT cohort)., Conclusions: Dysregulated expression of zinc transporters is involved in the progression of gliomas. Our results suggest that ZIP4 may serve as a potential diagnostic and prognostic marker for gliomas.

To analyze the clinical characteristics and prognostic factors in patients with glioma in an academic institute in China. From October 2004 to August 2010, total 1,285 patients were diagnosed as glioma at the Glioma Center of Beijing Tiantan Hospital. Clinical and molecular pathology features and survival rates were analyzed. The median overall survival (OS) times were 78.1, 37.6 and 14.4 months for low-grade glioma (WHO grade II), anaplastic glioma (WHO grade III) and glioblastoma (WHO grade IV), respectively. In patients with low-grade glioma, age, preoperative Karnofsky performance scale (KPS), pathological type, radiotherapy, O(6)-methylguanine-DNA methyltransferase (MGMT) expression and Ki-67 expression, were significantly associated with OS in multivariate analyses; and preoperative KPS and radiotherapy were significantly associated with progression-free survival (PFS). For anaplastic gliomas, age, preoperative KPS, pathological type, extent of resection, radiotherapy, p53 expression and phosphatase and tensin homolog (PTEN) expression were associated with OS. For glioblastomas, age, preoperative KPS, pathology type, extent of resection, radiotherapy and chemotherapy were associated with OS; and age, gender, preoperative KPS, extent of resection, radiotherapy and chemotherapy were associated with PFS. This is the largest survey for glioma management in China to date. We found significant differences in age, presenting symptoms and the expression of p53, MGMT, PTEN, and Ki-67 among patients with different types of glioma. Age, preoperative KPS, tumor grades, radiotherapy, chemotherapy and Ki-67 expression were significantly associated with clinical prognosis.

High-grade gliomas (HGGs) account for the vast majority of all gliomas, including glioblastoma (World Health Organization (WHO) grade IV) and anaplasticgliomas (WHO grade III). Despite tremendous efforts in developing multimodal treatments, the overall prognosis remains poor; however, survival time varies considerably between patients. The nature of diffuse permeation into surrounding brain parenchyma poses dilemma for neurosurgeons between extensive surgical resection to eliminate as much as tumor cells as possible and adverse effects associated with brain function. Heterogeneity in both cytology and gene expression makes it difficult to coordinate an effective therapy which works for every patient. This article reviews recent advancements in the molecular mechanism, multimodal treatment and clinical management, and the updated view on the biomarkers in patients with HGG, both in primary and recurrent setting, with an emphasis on targeted therapies tailored to the patient., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

To explore the expression pattern, prognostic value and functional role of stromal periostin (POSTN) in glioma patients, POSTN expression was measured using the Agilent Whole Human Genome Oligo Microarray in 220 frozen glioma tissues. We analyzed POSTN expression in 71 independent validated glioma samples using immuno-histochemistry. The expression levels of POSTN were relative to glioma grade progression and inversely correlated with overall survival in high-grade glioma patients (anaplastic gliomas and glioblastomas). Gene ontology (GO) analysis performed using DAVID showed that the gene sets related to cell migration and proliferation were significantly enriched in the cases with POSTN overexpression. Functional analyses in LN229 and U87 cells revealed that POSTN was involved in cell invasion and proliferation. MMP-9 was an effector of POSTN signaling in glioma cells. The expression of stromal protein POSTN is relative to glioma grade progression and confers a poor prognosis via promoting cellular invasion and proliferation in high-grade glioma patients.

MicroRNAs are strongly implicated as affecting glioma, but their specific roles and functions have yet to be fully elucidated. In this study, we defined the expression and function of miR-24, which we found to be upregulated in glioma samples and glioma cells by qRT-PCR. Downregulation of miR-24 in glioma cell lines inhibited proliferation and invasion and induced apoptosis. Using computational and expression analysis, ST7L was identified as a candidate target of miR-24. A reporter assay with the 3'UTR of ST7L cloned downstream of a luciferase gene showed increased luciferase activity in the absence of miR-24, providing strong evidence that miR-24 is a direct regulator of ST7L. Furthermore, we observed that restoration of ST7L activity resulted in effects that were similar to those from transfecting a miR-24 inhibitor into glioma cells. Mechanistic investigation revealed that the deletion of miR-24 suppressed β-catenin/Tcf-4 transcription activity by targeting ST7L. In conclusion, our study demonstrates that miR-24 upregulation is common in glioma and that suppression of miR-24 expression inhibits cell proliferation and invasion, suggesting that miR-24 may act as an oncogene in glioma., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Defining glioma subtypes based on objective genetic and molecular signatures may allow for a more rational, patient-specific approach to molecularly targeted therapy. However, prior studies attempting to classify glioma subtypes have given conflicting results. We aim to complement and validate the existing molecular classification system on a large number of samples from an East Asian population. A total of 225 samples from Chinese patients was selected for whole genome gene expression profiling. Consensus clustering was applied. Three major groups of gliomas were identified (referred to as G1, G2, and G3). The G1 subgroup correlates with a good clinical outcome, young age, and extremely high frequency of IDH1 mutations. Relative to the G1 subgroup, the G3 subgroup is correlated with a poorer clinical outcome, older age, and a very low rate of mutations in the IDH1 gene. Correlations of the G2 subgroup with respect to clinical outcome, age, and IDH1 mutation fall between the G1 and G3 subgroups. In addition, the G2 subtype was associated with a higher percentage of loss of 1p/19q when compared with G1 and G3 subtypes. Furthermore, our classification scheme was validated on 2 independent datasets derived from the cancer genome atlas (TCGA) and Rembrandt. With use of the TCGA classification system, proneural, neural, and mesenchymal, but not classical subtype, associated gene signatures were clearly defined. In summary, our results reveal that 3 main subtypes stably exist in Chinese patients with glioma. Our classification scheme may reflect the clinical and genetic alterations more clearly. Classical subtype-associated gene signature was not found in our dataset.

Notch pathway plays critical role in stem cell maintenance and angiogenesis, as well as cell fate decisions of cancer. However, concrete mechanisms of notch pathway regulation in glioma were not well known, especially mediated by microRNAs. In this study, we identified a brain-specific miRNA, miR-524-5p, which was associated with the pathological grade and overall survival of gliomas. Restorated expression of miR-524-5p in glioma suppressed cell proliferation and invasion both in vitro and in vivo. Using bioinformatics and biological approaches, we found that Jagged-1 and Hes-1, two key components of notch pathway, were direct targets of miR-524-5p. Knocking down of Jagged-1 or Hes-1 partially phenocopied miR-524-5p re-expression, whereas forced expression of Jagged-1 or Hes-1 reversed the effects of miR-524-5p on proliferation and invasion of glioma. Moreover, miR-524-5p levels in glioma samples were inversely correlated with Jagged-1 and Hes-1 and their overexpressions were associated with poor survival. Thus, we have identified that miR-524-5p behaves as a tumor suppressor by negatively targeting Jagged-1 and Hes-1 and provides an additional option to inhibit this oncogene in gliomas.

MicroRNAs are strongly implicated in cancer but their specific roles and functions in the major cancers have yet to be fully elucidated. In this study, we defined the expression and function of miR-137, which we found to be downregulated in glioma samples and glioma cells by qRT-PCR. Ectopic expression of miR-137 in glioma cell lines inhibited proliferation and invasion. Using computational and expression analysis, Cox-2 was identified as a candidate target of miR-137. Reporter assay with 3'UTR of Cox-2 cloned downstream of the luciferase gene showed reduced luciferase activity in the presence of miR-137, providing strong evidence that miR-137 was a direct regulator of Cox-2. Expression analysis further revealed that Cox-2 was elevated in glioma and associated with survival of patients. Furthermore, we observed that Cox-2 knockdown resulted in effects similar to those with miR-137 transfection in glioma cells. In conclusion, our study demonstrates that miR-137 deregulation is common in glioma, and restoration of its function inhibits cell proliferation and invasion, suggesting that miR-137 may act as a tumour suppressor., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The invasive behavior of glioblastoma multiforme (GBM) cells is one of the most important reasons for the poor prognosis of this cancer. For invasion, tumor cells must acquire an ability to digest the extracellular matrix and infiltrate the normal tissue bordering the tumor. Preventing this by altering effector molecules can significantly improve a patient's prognosis. Accumulating evidence suggests that miRNAs are involved in multiple biological functions, including cell invasion, by altering the expression of multiple target genes. The expression levels of miR-218 correlate with the invasive potential of GBM cells. In this study, we found that miR-218 expression was low in glioma tissues, especially in GBM. The data showed an inverse correlation in 60 GBM tissues between the levels of miR-218 and MMP mRNAs (MMP-2, -7 and -9). Additionally, ectopic expression of miR-218 suppressed the invasion of GBM cells whereas inhibition of miR-218 expression enhanced the invasive ability. Numerous members of the MMP family are downstream effectors of the Wnt/LEF1 pathway. Target prediction databases and luciferase data showed that LEF1 is a new direct target of miR-218. Importantly, western blot assays demonstrated that miR-218 can reduce protein levels of LEF1 and MMP-9. We, therefore, hypothesize that miR-218 directly targets LEF1, resulting in reduced synthesis of MMP-9. Results suggest that miR-218 is involved in the invasive behavior of GBM cells and by targeting LEF1 and blocking the invasive axis, miR-218-LEF1-MMPs, it may be useful for developing potential clinical strategies.

Aberrant microRNA expression has been implicated in the development of human cancers. Here, we investigated the oncogenic significance and function of miR-23b in glioma. We identified that the expression of miR-23b was elevated in both glioma samples and glioma cells, indicated by real-time polymerase chain reaction analyses. Down-regulation of miR-23b triggered growth inhibition, induced apoptosis, and suppressed invasion of glioma in vitro. Luciferase assay and Western blot analysis revealed that VHL is a direct target of miR-23b. Restoring expression of VHL inhibited glioma proliferation and invasion. Mechanistic investigation revealed that miR-23b deletion decreased HIF-1α/VEGF expression and suppressed β-catenin/Tcf-4 transcription activity by targeting VHL. Furthermore, expression of VHL was inversely correlated with miR-23b in glioma samples and was predictive of patient survival in a retrospective analysis. Therefore, we demonstrated that downregulation of miR-23b suppressed tumor survival through targeting VHL, leading to the inhibition of β-catenin/Tcf-4 and HIF-1α/VEGF signaling pathways.

Glioblastomas (GBMs) containing foci that resemble oligodendroglioma are defined as GBM with oligodendroglioma component (GBMO). However, whether GBMO is a distinct clinicopathological variant of GBM or merely represents a divergent pattern of differentiation remains controversial. We investigated 219 consecutive primary GBMs, of which 40 (18.3%) were confirmed as GBMOs. The clinical features and genetic profiles of the GBMOs were analyzed and compared with the conventional GBMs. The GBMO group showed more frequent tumor-related seizures (P= .027), higher frequency of IDH1 mutation (31% vs. <5%, P= .015), lower MGMT expression (P= .016), and longer survival (19.0 vs. 13.2 months; P= .022). In multivariate Cox regression analyses, presence of an oligodendroglioma component was predictive of longer survival (P= .001), but the extent of the oligodendroglial component appeared not to be linked to prognosis (P= .664). The codeletions of 1p/19q, somewhat surprisingly, were infrequent (<5%) in both GBMO and conventional GBM. In addition, the response to aggressive therapy differed: the GBMO group had no survival advantage associated with aggressive treatment protocols, whereas a clear treatment effect was observed in the conventional GBM group. Collectively, the clinical behavior and genetic alterations of GBMO thus differs from those of conventional GBM. Presence of an oligodendroglial component may therefore be a useful classification and stratification variable in therapeutic trials of GBMs.

It has been reported that IDH1 (IDH1R132) mutation was a frequent genomic alteration in grade II and grade III glial tumors but rare in primary glioblastoma (pGBM). To elucidate the frequency of IDH1 mutation and its clinical significance in Chinese patients with pGBM, one hundred eighteen pGBMs were assessed by pyro-sequencing for IDH1 mutation status, and the results were correlated with clinical characteristics and molecular pathological factors. IDH1 mutations were detected in 19/118 pGBM cases (16.1%). Younger age, methylated MGMT promoter, high expression of mutant P53 protein, low expression of Ki-67 or EGFR protein were significantly correlated with IDH1 mutation status. Most notably, we identified pGBM cases with IDH1 mutation were mainly involved in the frontal lobe when compared with those with wild-type IDH1. In addition, Kaplan-Meier survival analysis revealed a highly significant association between IDH1 mutation and a better clinical outcome (p = 0.026 for progression-free survival; p = 0.029 for overall survival). However, in our further multivariable regression analysis, the independent prognostic effect of IDH1 mutation is limited when considering age, preoperative KPS score, extent of resection, TMZ chemotherapy, and Ki-67 protein expression levels, which might narrow its prognostic power in Chinese population in the future.

Our previous miRNAs profiling study showed that miR-27b was up-regulated in glioma cells compared with H4 low grade astrocytoma cells. However, the main function of miR-27b in glioma in not known yet. The aim of this study was to investigate the expression and function of miR-27b in the pathogenesis of glioma. Real-time PCR showed that miR-27b was up-regulated in glioma samples and glioma cells. Down-regulation of miR-27b triggered growth inhibition, induced apoptosis and inhibited invasion in glioma cells. Furthermore, TOPflash luciferase activity was decreased significantly, while FOPflash luciferase did not change significantly. In addition, Western blot assay showed that STAT3, c-myc and cyclin D1 were knocked down after treatment with miR-27b inhibitor. These findings suggest that aberrantly up-regulated miR-27b may be one of the critical factors that contribute to malignancy in human gliomas.

Activation of signal transducer and activator of transcription 3 (STAT3) is associated with poor clinical outcome of glioblastoma (GBM). However, the role of STAT3 in resistance to alkylator-based chemotherapy remains unknown. Here, we retrospectively analyzed the phosphorylated STAT3 (p-STAT3) profile of 68 GBM patients receiving alkylator therapy, identifying p-STAT3 as an independent unfavorable prognostic factor for progression-free and overall survival. Additionally, elevated p-STAT3 expression correlated with resistance to alkylator therapy. In vitro analysis revealed that U251 and U87 human glioma cells were refractory to treatment with the common alkylating agent temozolomide (TMZ), with only a modest impact on AKT and β-catenin activation in the context of high p-STAT3. Inhibition of STAT3 in these cells significantly enhanced the effect of TMZ. Inhibition of STAT3 dramatically decreased the IC50 of TMZ, increasing TMZ-induced apoptosis while up-regulating expression of Bcl-2 and down-regulating expression of Bax. Furthermore, inhibition of STAT3 increased TMZ-induced G₀-G₁ arrest and decreased Cyclin D1 expression compared to TMZ alone. Together, these results indicate that inhibition of STAT3 sensitizes glioma cells to TMZ, at least in part, by blocking the p-AKT and β-catenin pathways. These findings strongly support the hypothesis that STAT3 inhibition significantly improves the clinical efficacy of alkylating agents.

The poor prognosis of glioblastoma multiforme (GBM) is largely attributed to their highly invasive nature and MMP-9 plays a pivotal role in regulating invasiveness of malignant glioma cells. MicroRNAs (miRNAs) are small non-coding RNAs that have been shown to regulate a wide range of biological processes via targeting messenger RNA. Previous reports have shown many oncogenes regulate survival and invasion via targeting MMP-9 in GBM. But no literature indicates that miRNAs regulate glioma cell invasion through targeting MMP-9. Here, we show MMP-9 overexpression conferred a poor prognosis in 163 GBM patients. Furthermore, MMP-9 specific miRNA expression profile (14 positively and 31 negatively correlated miRNAs with MMP-9) was established via miRNA microarrays in 60 GBM samples. Among them, two miRNAs: miR-885-5p and miR-491-5p, were chosen for functional validation for their high positive correlation with MMP-9 expression. And upregulation of miR-885-5p and miR-491-5p were demonstrated to reduce the levels of MMP-9 expression and inhibit cellular invasion in U251 and U87 glioma cells. Furthermore, we found that miR-491-5p suppressed glioma cell invasion via targeting MMP-9 directly. To our knowledge, this is the first study to identify the MMP-9 specific microRNA signature which may provide potential targets for anti-invasion therapy in GBM., (Copyright © 2011 Elsevier B.V. All rights reserved.)