Glioblastoma ; genetics ; metabolism ; Humans ; Mutation ; Oncogene Proteins ; genetics ; metabolism ; Tumor Suppressor Proteins ; genetics ; metabolism

Patients with glioblastoma (GBM) generally have a bad prognosis and short overall survival after being treated with surgery, chemotherapy or radiotherapy due to the histological heterogeneity, strong invasive ability and rapid postoperative recurrence of GBM. The components of GBM cell-derived exosome (GBM-exo) can regulate the proliferation and migration of GBM cell via cytokines, miRNAs, DNA molecules and proteins, promote the angiogenesis via angiogenic proteins and non-coding RNAs, mediate tumor immune evasion by targeting immune checkpoints with regulatory factors, proteins and drugs, and reduce drug resistance of GBM cells through non-coding RNAs. GBM-exo is expected to be an important target for the personalized treatment of GBM and a marker for diagnosis and prognosis of this kind of disease. This review summarizes the preparation methods, biological characteristics, functions and molecular mechanisms of GBM-exo on cell proliferation, angiogenesis, immune evasion and drug resistance of GBM to facilitate developing new strategies for the diagnosis and treatment of GBM.
Humans ; Glioblastoma/genetics* ; Exosomes/metabolism* ; MicroRNAs/metabolism* ; Prognosis ; Cell Proliferation ; Brain Neoplasms/genetics* ; Cell Line, Tumor

OBJECTIVETo reveal the molecular genetic mechanisms for the pathogenesis of glioblastoma (GBM) and determine which chromosomes or chromosomal regions may play a role in the pathogenesis of GBM or may harbor tumor suppressor genes (TSGs) associated GBM.

METHODSAn allelotype study of 21 cases of GBM was performed by polymerase chain reaction and loss of heterozygosity (LOH) analysis. Three hundred and eighty-two microsatellite markers covering all 22 autosomes were used. The mean genetic distance between two flanking markers is about 10 cM. Fluorescent dye-labeled primers and Perkin Elmer 377 DNA Sequencer were applied.

RESULTSLOH was observed on all chromosomal arms examined in this study. The LOH frequencies of 10q, 10p, 13q, 17p and 9p were the highest (>50%), on which high LOH frequencies were detected at the regions resided by the known TSGs including PTEN, DMBT1, p16, p15, p53 and Rb. The following commonly deleted regions were detected: 9p22-23, 10p12.2-14, 10q21.3, 13q12.1-14.1, 13q14.3-31, 17p11.2-12, 17p13, 3q24-27, 11p12-13, 14q31-32.3, 14q21-24.1, 22q13.2-13.3, 4q35, 4q31.1-31.2, 6qtel, 6q16.3.

CONCLUSIONThis study demonstrated that the pathogenesis of GBM is very complicated and associated with various molecular genetic abnormalities on lots of chromosomes. The chromosomal arms most closely relevant to the pathogenesis of GBM are 10q, 10p, 9p, 17p and 13q. Besides the well-known TSGs, such as PTEN, DMBT1, p16, p15, p53 and Rb, multiple unknown TSGs associated with GBM may be present on the commonly deleted regions observed for the first time in this study.

Adult ; Aged ; Chromosomes, Human ; genetics ; DNA, Neoplasm ; genetics ; Female ; Glioblastoma ; genetics ; Humans ; Loss of Heterozygosity ; Male ; Microsatellite Repeats ; Middle Aged

BACKGROUNDSite A132Arg mutations potentially impair the affinity of isocitrate dehydrogenase 1 (IDH1) for its substrate isocitrate (ICT), consequently reducing the production of α-ketoglutarate and leading to tumor growth through the induction of the hypoxia-inducible factor-1 (HIF-1) pathway. However, given that the roles of other active sites in IDH1 substrate binding remain unclear, we aimed to investigate IDH1 mutation pattern and its influence on enzyme function.

METHODSFifteen IDH1 catalytic active site candidates were selected for in silico mutagenesis and protein homology modeling. Binding free energy of the IDH1/ICT complexes with single-site mutations was compared with that of the wild type. The affinity of 10 IDH1 catalytic active sites for the ICT substrate was further calculated.

RESULTSThe IDH1 active site included seven residues from chain A (A77Thr, A94Ser, A100Arg, A132Arg, A109Arg, A275Asp, and A279Asp) and three residues from chain B (B214Thr, B212Lys, and B252Asp) that constituted the substrate ICT-binding site. These residues were located within 0.5 nm of ICT, indicating a potential interaction with the substrate. IDH1 changes of binding free energy (ΔE) suggested that the A132Arg residue from chain A contributes three hydrogen bonds to the ICT α-carboxyl and β-carboxyl groups, while the other nine residues involved in ICT binding form only one or two hydrogen bonds. Amino acid substitutes at A132Arg, A109Arg, and B212Lys sites, had the greatest effect on enzyme affinity for its substrate.

CONCLUSIONSMutations at sites A132Arg, A109Arg, and B212Lys reduced IDH1 affinity for ICT, indicating these active sites may play a central role in substrate binding. Mutations at sites A77Thr, A94Ser, and A275Asp increased the affinity of IDH1 for ICT, which may enhance IDN1 catalytic activity. Mutant IDH1 proteins with higher catalytic activity than the wild-type IDH1 could potentially be used as a novel gene therapy for glioblastoma multiforme.

Catalytic Domain ; genetics ; Glioblastoma ; genetics ; Humans ; Isocitrate Dehydrogenase ; genetics ; metabolism ; Isocitrates ; metabolism ; Mutagenesis ; Mutation ; Protein Binding ; Structure-Activity Relationship

BACKGROUND: Mixed gliomas, such as oligoastrocytomas (OA), anaplastic oligoastrocytomas, and glioblastomas (GBMs) with an oligodendroglial component (GBMO) are defined as tumors composed of a mixture of two distinct neoplastic cell types, astrocytic and oligodendroglial. Recently, mutations ATRX and TP53, and codeletion of 1p/19q are shown to be genetic hallmarks of astrocytic and oligodendroglial tumors, respectively. Subsequent molecular analyses of mixed gliomas preferred the reclassification to either oligodendroglioma or astrocytoma. This study was designed to apply genetically integrated diagnostic criteria to mixed gliomas and determine usefulness and prognostic value of new classification in Korean patients. METHODS: Fifty-eight cases of mixed OAs and GBMOs were retrieved from the pathology archives of Seoul National University Hospital from 2004 to 2015. Reclassification was performed according to genetic and immunohistochemical properties. Clinicopathological characteristics of each subgroup were evaluated. Overall survival was assessed and compared between subgroups. RESULTS: We could reclassify all mixed OAs and GBMOs into either astrocytic or oligodendroglial tumors. Notably, 29 GBMOs could be reclassified into 11 cases of GBM, IDH-mutant, 16 cases of GBM, IDH-wildtype, and two cases of anaplastic oligodendroglioma, IDH mutant. Overall survival was significantly different among these new groups (p<.001). Overall survival and progression-free survival were statistically better in gliomas with IDH mutation, ATRX mutation, no microscopic necrosis, and young patient age (cut off, 45 years old). CONCLUSIONS: Our results strongly suggest that a genetically integrated diagnosis of glioma better reflects prognosis than former morphology-based methods.
Astrocytoma ; Classification ; Diagnosis ; Disease-Free Survival ; Genetics ; Glioblastoma ; Glioma ; Humans ; Necrosis ; Oligodendroglioma ; Pathology ; Prognosis ; Seoul

Glioblastoma is the most common intracranial primary malignant tumor, which leads to the poor quality of life of patients and has a high recurrence rate. Chemotherapy is a vital part in the treatment of this disease. Tetrandrine(Tet) is an active ingredient extracted from the root of the Chinese medicinal plant Stephania tetrandra, which has been proved with a wide range of pharmacological effects including anti-tumor. However, there are few studies regarding the effect of Tet on glioma. In this study, MTT and BrdU assays were employed to detect the effect of Tet on the proliferation of LN229 glioblastoma cells; flow cytometry was used to analyze the cycle distribution and apoptosis; plate cloning assay and soft agar colony formation assay were performed to study the colony formation ability of LN229 cells exposed to Tet; scratch assay and Transwell assay were conducted to detect the ability of migration and invasion; Western blot was adopted to the exploration of the molecular mechanism. The MTT and BrdU assays showed that Tet inhibited the proliferation of LN229 cells in a time-and dose-dependent manner. The plate cloning assay and soft agar colony formation assay showed that Tet weakened the colony formation of LN229 cells in vitro; cytometry assay showed that Tet blocked cells in the G_1 phase and promoted cell apoptosis; scratch and Transwell assays proved that Tet inhibited the migration and invasion of LN229 cells; Western blot results showed that Tet down-regulated the expression levels of CDK2, CDK6, cyclin D1, cyclin E1, snail, slug, vimentin, and N-cadherin, while up-regulated the level of E-cadherin. The results indicate that Tet has a certain inhibitory effect on the proliferation, migration, and invasion of LN229 glioblastoma cells, and such effect may be related to the participation of Tet in the regulation of c-Myc/p27 axis and snail signaling pathway.
Apoptosis ; Benzylisoquinolines ; Cell Line, Tumor ; Cell Movement ; Cell Proliferation ; Glioblastoma/genetics* ; Humans ; Quality of Life

OBJECTIVETo summary the recent advances in molecular research of glioblastoma (GBM) and current trends in personalized therapy of this disease.

DATA SOURCESData cited in this review were obtained mainly from PubMed in English up to 2015, with keywords "molecular", "genetics", "GBM", "isocitrate dehydrogenase", "telomerase reverse transcriptase", "epidermal growth factor receptor", "PTPRZ1-MET", and "clinical treatment".

STUDY SELECTIONArticles regarding the morphological pathology of GBM, the epidemiology of GBM, genetic alteration of GBM, and the development of treatment for GBM patients were identified, retrieved, and reviewed.

RESULTSThere is a large amount of data supporting the view that these recurrent genetic aberrations occur in a specific context of cellular origin, co-oncogenic hits and are present in distinct patient populations. Primary and secondary GBMs are distinct disease entities that affect different age groups of patients and develop through distinct genetic aberrations. These differences are important, especially because they may affect sensitivity to radio- and chemo-therapy and should thus be considered in the identification of targets for novel therapeutic approaches.

CONCLUSIONThis review highlights the molecular and genetic alterations of GBM, indicating that they are of potential value in the diagnosis and treatment for patients with GBM.

Brain Neoplasms ; genetics ; pathology ; Glioblastoma ; genetics ; pathology ; Humans ; Isocitrate Dehydrogenase ; genetics ; Mutation ; PTEN Phosphohydrolase ; genetics ; Receptor, Epidermal Growth Factor ; genetics ; Telomerase ; genetics

The purpose of this study was to investigate the molecular mechanism by which miR-21 and its target genes mediate radiation resistance of glioblastoma cells. Real-time PCR was employed to detect miR-21 expression in normal brain tissues, glioblastoma tissues and glioblastoma cell lines (A172, T98G and U87MG). T98G cells were transfected with anti-miR-21 oligonucleotides, or plasmids containing PDCD4 or hMSH2 (PDCD4-pcDNA3 and hMSH2-pcDNA3). The survival curve was obtained to investigate the sensitivity of T98G cells to radiation. Cell apoptosis was measured by using the Caspase-3/7 kit and cell cycle by flow cytometry. Western blotting was performed to detect the expression of hMSH2 and PDCD4 in miR-21-inhibiting T98G cells. The results showed that miR-21 expression in glioblastoma cells and tissues was conversely associated with the radiation sensitivity. Over-expression of miR-21 resulted in radiation resistance, while knockdown of miR-21 led to higher sensitivity of glioblastma cells to radiation. After miR-21 knockdown, the apoptosis of T98G cells was significantly increased and the G(2) phase arrest was more significant. In addition, miR-21 knockdown increased the expression of endogenous PDCD4 and hMSH2, which contributed to the apoptosis and G(2) arrest of T98G cells. The findings suggested that miR-21 may mediate the resistance of glioblastoma cells against radiation via its target genes PDCD4 and hMSH2. MiR-21 and its target genes may be used as potential molecular targets for clinical radiotherapy sensitization in the future.
Apoptosis Regulatory Proteins ; genetics ; Cell Line, Tumor ; Glioblastoma ; genetics ; Humans ; MicroRNAs ; genetics ; MutS Homolog 2 Protein ; genetics ; RNA-Binding Proteins ; genetics ; Radiation Tolerance ; genetics

BACKGROUND: Epithelial to mesenchymal transition (EMT) is strongly linked with tumor invasion and metastasis, which performs a vital role in carcinogenesis and cancer progression. Emerging evidence suggests that microRNAs (miRNAs) expression are closely associated to EMT by regulating targeted genes. MiR542 has been found to be involved in the EMT program and bound up with various cancers. However, the functions of miR542 and its underlying mechanism in glioblastoma multiforme (GBM) remain largely unknown. In the current study, we investigated the effect of astrocyte elevated gene-1 (AEG-1) on U251 cells aggressiveness, proliferation, apoptosis, and cell cycle. METHODS: The screening of targeted miRNAs was performed, as well as the functional roles and mechanisms of miR542 were explored. RESULTS: MiR542 was selected as the target because of the most significantly differential expression and this high level of expression negatively correlated with cell migration and proliferation, which suggested that miR542 could be a novel tumor suppressor. Moreover, we confirmed that AEG-1 was a direct targeted gene of miR542 by luciferase activity assay, reverse transcription-polymerase chain reaction, and immunoblotting analysis. Furthermore, miR542 suppressed the expression of AEG-1, which upgraded the level of E-cadherin and degraded Vimentin expression contributing to retraining EMT. CONCLUSION The in vitro findings demonstrated that miR542 inhibited the migration and proliferation of U251 cells and suppressed EMT through targeting AEG-1, indicating that miR542 may be a potential anti-cancer target for GBM.
Astrocytes ; Cell Line, Tumor ; Cell Movement/genetics* ; Cell Proliferation/genetics* ; Epithelial-Mesenchymal Transition/genetics* ; Gene Expression Regulation, Neoplastic ; Glioblastoma/genetics* ; Humans ; MicroRNAs/genetics* ; Neoplasm Invasiveness/genetics*

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.
Aged ; Brain Neoplasms/genetics* ; Drug Resistance ; Glioblastoma ; Glioma/genetics* ; Humans ; Mutation ; Neoplasm Recurrence, Local/drug therapy* ; Tumor Microenvironment