Glioma is the most common and lethal intrinsic primary tumor of the brain. Its controversial origins may contribute to its heterogeneity, creating challenges and difficulties in the development of therapies. Among the components constituting tumors, glioma stem cells are highly plastic subpopulations that are thought to be the site of tumor initiation. Neural stem cells/progenitor cells and oligodendrocyte progenitor cells are possible lineage groups populating the bulk of the tumor, in which gene mutations related to cell-cycle or metabolic enzymes dramatically affect this transformation. Novel approaches have revealed the tumor-promoting properties of distinct tumor cell states, glial, neural, and immune cell populations in the tumor microenvironment. Communication between tumor cells and other normal cells manipulate tumor progression and influence sensitivity to therapy. Here, we discuss the heterogeneity and relevant functions of tumor cell state, microglia, monocyte-derived macrophages, and neurons in glioma, highlighting their bilateral effects on tumors. Finally, we describe potential therapeutic approaches and targets beyond standard treatments.
Humans ; Glioma/metabolism* ; Neuroglia/metabolism* ; Carcinogenesis/pathology* ; Neural Stem Cells/metabolism* ; Microglia/metabolism* ; Brain Neoplasms/metabolism* ; Tumor Microenvironment

OBJECTIVE: To determine whether U(251) cells are permissive for human cytomegalovirus (HCMV), and to investigate the characteristics of temporal expression of proteins IE1 and pp65. METHODS: U(251) cells were infected with HCMV, and then the cells were observed under the transmission electronic microscope, and the viral nucleic acid was detected by PCR, and the expression levels of IE1 and pp65 were analyzed by immunohistochemical assay with anti-IE1 monoclonal antibody and anti-pp65 monoclonal antibody at various time spost infection. RESULTS: Morphological changes of the infected cells appeared under the transmission electron microscope. The viral nucleic acid was detected successfully by PCR. The expression of IE1 was detected firstly at 4h post infection, and reached a peak within 14h, and then decreased. The incoming pp65 was detected at 1h, the low expression levels of pp65 were detected firstly at 4h, and they could remain relatively constant through 96 h, but the maximum expression occurred at 120 h. CONCLUSION Human glioma U(251) cells are permissive for HCMV, the temporal cascade of HCMV gene expression can be observed in the infected U(251) cells, but it is delayed obviously in the human fibroblast.
Cell Line, Tumor ; Cytomegalovirus ; Cytomegalovirus Infections ; Glioma ; metabolism ; virology ; Humans ; Immediate-Early Proteins ; metabolism ; Phosphoproteins ; metabolism ; Viral Matrix Proteins ; metabolism

BACKGROUNDP53 is one of the most studied tumor suppressors in the cancer research, and over 50% of human tumors carry P53 mutations. MDM-2 is amplified and/or overexpressed in a variety of human tumors of diverse tissue origin. The aim of this study was to examine the expression of P53 protein and MDM-2 protein in gliomas, and to investigate the relationship between the expression of the two proteins and the histopathological grades of glioma. The relationship between MDM-2 protein expression and P53 protein expression was also analyzed.

METHODSThe expression of P53 protein and MDM-2 protein was immunohistochemically detected using monoclonal antibodies in 242 paraffin embedded tissues, including 30 normal brain tissues from patients with craniocerebral injury and 212 tissues from patients with primary glioma (grade I - II group: 5 cases of grade I, 119 cases of grade II; and grade III--IV group: 53 cases of grade III, and 35 cases of grade IV).

RESULTSThe P53 positive rate was significantly higher in the glioma groups than in the control group (P < 0.0001). The P53 positive rate was significantly higher in glioma tissues of grade III - IV than in glioma tissues of grade I - II group (P = 0.001). The MDM-2 positive rate was significantly higher in glioma groups than in the control group (P < 0.0001). There was no significant difference in the MDM-2 positive rate between the two glioma groups (P = 0.936). The expression of P53 protein was not related to expression of MDM-2 protein (P = 0.069)

CONCLUSIONSOverexpression of P53 protein might be related to the occurrence and progression of glioma. Overexpression of MDM-2 protein may play an important role in glioma tumorigenesis, but may not be involved in glioma progression. The overexpression of MDM-2 protein was an early event in malignant transformation of glioma. MDM-2 may be a key player in glioma in its own right.

Glioma ; metabolism ; pathology ; Humans ; Immunohistochemistry ; In Vitro Techniques ; Proto-Oncogene Proteins c-mdm2 ; metabolism ; Tumor Suppressor Protein p53 ; metabolism

OBJECTIVETo review the leading roles of glioma stem cells (GSCs) and their sophisticated interactions with other cells in the tissue remodeling process of gliomagenesis.

DATA SOURCESPublished articles about assessing GSCs in tumor initiation, progression, and multiple interactions with other cells in the special microenvironment were selected using PubMed. The search terms were "glioma stem cells", "tumorigenesis", and "microenvironment".

STUDY SELECTIONArticles regarding the tissue remodeling of GSCs in gliomagenesis were selected.

RESULTSGSCs exhibit enhanced tumor-initiating ability, could reestablish tumor, and were resistant to radiotherapy and chemotherapy. Studying the role of GSCs in gliomagenesis helps to develop targeting therapy against GSCs, which seems to be a cure for gliomas. However, sophisticated interactions between GSCs and their local microenvironment during tumor remodeling, including integrating with partially differentiated tumor cells, GSCs niche, neural stem cells (NSCs), normal glia, tumor-infiltrating lymphocytes, may obscure the leading role of GSCs during gliomagenesis, and make single targeting therapy unsuccessful.

CONCLUSIONSUnderstanding the biological behaviour of GSCs and their regulatory mechanisms may directly impact current efforts for more directed therapeutics against the highly aggressive gliomas. For multiple possible sources to turning into GSCs, simply eradicating the existing GSCs is not enough to be a cure for gliomas, blocking the potential sources of GSCs and ameliorating the local tumor inducing/promoting microenvironment should be a reasonable strategy.

AC133 Antigen ; Antigens, CD ; Biomarkers, Tumor ; metabolism ; Glioma ; metabolism ; pathology ; Glycoproteins ; Humans ; Neoplastic Stem Cells ; metabolism ; pathology ; Peptides

To explore the magnetic resonance imaging (MRI) characteristics of glioma with Brg/Brm-associated factor 53a (BAF53a) expression.
 Methods: A total of 121 patients with glioma was divided into a BAF53a high expression group (n=79) and a low expression group (n=42) according to the results of immunohistochemistry. Then the MRI characteristics, including lesion location, number, boundary, maximum diameter, peripheral edema, midline structure shift, homogeneity, cystic necrosis, hemorrhage, strengthening degree, ependymal strengthening, pia mater enhancement, deep white matter invasion and lesion across the midline (total 14 items), were analyzed.
 Results: The results showed that there were significance difference in lesion border, lesion edema, enhancement of the lesion, and deep white matter invasion between the 2 groups (all P<0.05).
 Conclusion: The MRI characteristics, such as lesion border, lesion edema degree, enhancement degree of the lesion and deep white matter invasion, might be associated with BAF53a expression in gliomas.
Actins ; metabolism ; Brain Neoplasms ; Chromosomal Proteins, Non-Histone ; metabolism ; DNA-Binding Proteins ; metabolism ; Glioma ; Humans ; Magnetic Resonance Imaging ; Necrosis

BACKGROUNDIn vivo proton magnetic resonance spectroscopy (MRS) provides a noninvasive method of examining a wide variety of cerebral metabolites in both healthy subjects and patients with various brain diseases. Absolute metabolite concentrations have been determined using external and internal standards with known concentrations. When an external standard is placed beside the head, variations in signal amplitudes due to B1 field inhomogeneity and static field inhomogeneity may occur. Hence an internal standard is preferable. The purpose of this study was to quantitatively analyze the metabolite concentrations in normal adult brains and gliomas by in vivo proton MRS using the fully relaxed water signal as an internal standard.

METHODSBetween January 1998 and October 2001, 28 healthy volunteers and 16 patients with gliomas were examined by in vivo proton MRS. Single-voxel spectra were acquired using the point-resolved spectroscopic pulse sequence with a 1.5 T scanner (TR/TE/Ave = 3000 ms/30 ms/64).

RESULTSThe calculated concentrations of N-acetyl-asparatate (NAA), creatine (Cre), choline (Cho), and water (H2O) in the normal hemispheric white matter were (23.59 +/- 2.62) mmol/L, (13.06 +/- 1.8) mmol/L, (4.28 +/- 0.8) mmol/L, and (47,280.96 +/- 5414.85) mmol/L, respectively. The metabolite concentrations were not necessarily uniform in different parts of the brain. The concentrations of NAA and Cre decreased in all gliomas (P < 0.001). The ratios of NAA/Cho and NAA/H2O showed a significant difference between the normal brain and gliomas, and also between the high and low grades (P < 0.001).

CONCLUSIONSQuantitative analysis of in vivo proton MR spectra using the fully relaxed water signal as an internal standard is useful. The concentrations of NAA and the ratios of NAA/H2O and NAA/Cho conduce to discriminating between the glioma and normal brain, and also between the low-grade glioma and high-grade glioma.

Adult ; Aspartic Acid ; analogs & derivatives ; metabolism ; Brain ; metabolism ; Choline ; metabolism ; Creatine ; metabolism ; Female ; Glioma ; metabolism ; Glycine ; metabolism ; Humans ; Inositol ; metabolism ; Magnetic Resonance Spectroscopy ; Male

OBJECTIVETo investigate the anti-tumor effects of melittin against malignant human glioma cells in vitro.

METHODSTwo malignant human glioma cell lines (U87 and U251) were treated with melittin at various concentrations, and the cell growth inhibition and apoptosis were evaluated using MTT assay, flow cytometry and agarose gel electrophoresis.

RESULTSMelittin could obviously inhibit the proliferation of the two glioma cell lines (P<0.05). At the concentrations of 1, 10, 20, 40, 80, 160, 200 mg/L, melittin resulted in U87 cell apoptosis rates of 12.80%, 16.92%, 22.69%, 34.05%, 41.82%, 59.87%, and 80.25%, and in U251 cell apoptosis rate of 11.61%, 16.21%, 22.03%, 30.57%, 41.10%, 58.33%, and 79.12%, respectively, showing a dose-dependent effect in its action of inducing cell apoptosis.

CONCLUSIONMelittin inhibits the proliferation and induces apoptosis of malignant human glioma cell lines in vitro.

Apoptosis ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Glioma ; metabolism ; pathology ; Humans ; Melitten ; pharmacology

Objective To investigate the relationship between the expression of glutathione peroxidase(GPX)genes and the clinical prognosis in glioma patients,and to construct and evaluate the model for predicting the prognosis of glioma. Methods The clinical information and GPX expression of 663 patients,including 153 patients of glioblastoma(GBM)and 510 patients of low-grade glioma(LGG),were obtained from The Cancer Genome Atlas(TCGA)database.The relationship between GPX expression and patient survival was analyzed.The key GPX affecting the prognosis of glioma was screened out by single- and multi-factor Cox's proportional-hazards regression models and validated by least absolute shrinkage and selection operator(Lasso)regression.Finally,we constructed the model for predicting the prognosis of glioma with the screening results and then used concordance index and calibration curve respectively to evaluate the discrimination and calibration of model. Results Compared with those in the control group,the expression levels of GPX1,GPX3,GPX4,GPX7,and GPX8 were up-regulated in glioma patients(all P<0.001).Moreover,the expression levels of other GPX except GPX3 were higher in GBM patients than in LGG patients(all P<0.001).The Kaplan-Meier curves showed that the progression-free survival of GBM with high expression of GPX1(P=0.013)and GPX4(P=0.040),as well as the overall survival,disease-specific survival,and progression-free survival of LGG with high expression of GPX1,GPX7,and GPX8,was shortened(all P<0.001).GPX7 and GPX8 were screened out as the key factors affecting the prognosis of LGG.The results were further used to construct a nomogram model,which suggested GPX7 was the most important variable.The concordance index of the model was 0.843(95%CI=0.809-0.853),and the calibration curve showed that the predicted and actual results had good consistency. Conclusion GPX7 is an independent risk factor affecting the prognosis of LGG,and the nomogram model constructed with it can be used to predict the survival rate of LGG.
Brain Neoplasms ; Glioblastoma ; Glioma/diagnosis* ; Glutathione Peroxidase/metabolism* ; Humans ; Peroxidases ; Prognosis ; Proportional Hazards Models

BACKGROUNDRecent studies have suggested that cancer stem cells are one of the major causes for tumor recurrence due to their resistance to radiotherapy and chemotherapy. Although the highly invasive nature of glioblastoma (GBM) cells is also implicated in the failure of current therapies, it is not clear how glioma stem cells (GSCs) are involved in invasiveness. Rac1 activity is necessary for inducing reorganization of actin cytoskeleton and cell movement. In this study, we aimed to investigate the distribution characteristics of CD133+ cells and Rac1+ cells in GBM as well as Rac1 activity in CD133+ GBM cells, and analyze the migration and invasion potential of these cells.

METHODSA series of 21 patients with GBM were admitted consecutively and received tumor resection in Tianjin Medical University General Hospital during the first half of the year 2011. Tissue specimens were collected both from the peripheral and the central parts for each tumor under magnetic resonance imaging (MRI) navigation guidance. Immunohistochemical staining was used to detect the CD133+ cells and Rac1+ cells distribution in GBM specimens. Double-labeling immunofluorescence was further used to analyze CD133 and Rac1 co-expression and the relationship between CD133+ cells distribution and Rac1 expression. Serum-free medium culture and magnetic sorting were used to isolate CD133+ cells from U87 cell line. Rac1 activation assay was conducted to assess the activation of Rac1 in CD133+ and CD133 - U87 cells. The migration and invasive ability of CD133+ and CD133 - U87 cells were determined by cell migration and invasion assays in vitro. Student's t-test and one-way analysis of variance (ANOVA) test were used to determine statistical significance in this study.

RESULTSIn the central parts of GBMs, CD133+ cells were found to cluster around necrosis and occasionally cluster around the vessels under the microscope by immunohistological staining. In the peripheral parts of the tumors, CD133+ cells were lined up along the basement membrane of the vessels and myelinated nerve fibers. Rac1 expression was high and diffused in the central parts of the GBMs, and the Rac1+ cells were distributed basically in accordance with CD133+ cells both in the central and peripheral parts of GBMs. In double-labeling immunofluorescence, Rac1 was expressed in (83.14 ± 4.23)% of CD133+ cells, and CD133 and Rac1 co-expressed cells were located around the vessels in GBMs. Significantly higher amounts of Rac1-GTP were expressed in the CD133+ cells (0.378 ± 0.007), compared to CD133- cells (0.195 ± 0.004) (t = 27.81; P < 0.05). CD133+ cells had stronger ability to migrate (74.34 ± 2.40 vs. 38.72 ± 2.60, t = 42.71, P < 0.005) and invade (52.00 ± 2.28 vs. 31.26 ± 1.82, t = 30.76, P < 0.005), compared to their counterpart CD133- cells in transwell cell migration/invasion assay.

CONCLUSIONSThese data suggest that CD133+ GBM cells highly express Rac1 and have greater potential to migrate and invade through activated Rac1-GTP. The accordance of distribution between Rac1+ cells and CD133+ cells in GBMs implies that Rac1 might be an inhibited target to prevent invasion and migration and to avoid malignant glioma recurrence.

AC133 Antigen ; Antigens, CD ; metabolism ; Cell Line, Tumor ; Glioblastoma ; metabolism ; pathology ; Glioma ; metabolism ; pathology ; Glycoproteins ; metabolism ; Humans ; Immunohistochemistry ; In Vitro Techniques ; Peptides ; metabolism ; rac1 GTP-Binding Protein ; metabolism

OBJECTIVETo investigate the effect of quercetin on apoptosis and feedback regulation of MDM2-p53 in multiform glioblastoma U87 cells in vitro.

METHODSU87 cells exposed to different concentrations of quercetin (50, 100, and 150 µmol/L) were examined with flow cytometry, RT-PCR and Western blotting for detecting the cell apoptosis, MDM2 mRNA expression, and p53 and caspase-3 expressions.

RESULTSQuercetin induced obvious apoptosis in U87 cells in a concentration-dependent manner, with apoptosis rates of (12.40∓0.70)% at Q0, (22.53∓0.72)% at Q50, (29.06∓0.81)% at Q100, and (31.5∓0.45)% at Q150. Quercetin significantly increased the expressions of MDM2 mRNA and active caspase-3 protein but decreased the expression of p53 in the cells.

CONCLUSIONQuercetin promotes the apoptosis of multiform glioblastoma U87 cells mediated by caspase-3 and influences the feedback balance of MDM2-p53.

Apoptosis ; Caspase 3 ; metabolism ; Cell Line, Tumor ; drug effects ; Glioma ; metabolism ; pathology ; Humans ; Proto-Oncogene Proteins c-mdm2 ; metabolism ; Quercetin ; pharmacology ; Tumor Suppressor Protein p53 ; metabolism