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Glioma Cell Lines (glioma + cell_line)
Kinds of Glioma Cell Lines Selected AbstractsRASSF1A, BLU, NORE1A, PTEN and MGMT Expression and Promoter Methylation in Gliomas and Glioma Cell Lines and Evidence of Deregulated Expression of de novo DNMTsBRAIN PATHOLOGY, Issue 2 2009Aiala Lorente Abstract Methylation of CpG islands in gene promoters can lead to gene silencing. Together with deletion or mutation, it may cause a loss of function of tumor suppressor genes. RASSF1A (3p21.3), NORE1A (1q32.1) and BLU (3p21.3) have been shown to be downregulated by methylation in cancer, and PTEN (10q23.3) and MGMT (10q26.1) are located in areas commonly deleted in astrocytomas. MGMT methylation predicts a better response and a longer overall survival in patients with glioblastomas treated with temozolomide. We analyzed 53 astrocytoma samples and 10 high-grade glioma cell lines. Gene expression was assessed by RT-PCR. Bisulfite sequencing, MSP and a melting curve analysis-based real-time PCR were performed to detect promoter methylation. Treatments with 5,-aza-2,-deoxicitidine were applied to restore gene expression in cell lines. Ninety-two percent of tumor samples were methylated for RASSF1A, 30%,57% for BLU and 47% for MGMT, suggesting promoter methylation of these genes to be a common event in glioma tumorigenesis. Only 4% of the tumors revealed a methylated promoter for NORE1A. No association between methylation and loss of expression could be established for PTEN. We identified de novo DNMTs overexpression in a subset of tumors which may explain the methylation phenotype of individual gliomas. [source] Expression of T-type calcium channel splice variants in human gliomaGLIA, Issue 2 2004Isabelle Latour Abstract In humans, three isoforms of the T-type (Cav3.1) calcium-channel ,1 subunit have been reported as a result of alternate splicing of exons 25 and 26 in the III,IV linker region (Cav3.1a, Cav3.1b or Cav3.1bc). In the present study, we report that human glioma express Cav3.1 channels in situ, that splicing of these exons is uniquely regulated and that there is expression of a glioma-specific novel T-type variant (Cav3.1ac). Seven human glioma samples were collected at surgery, RNA was extracted, and cDNA was produced for RT-PCR analysis. In addition, three glioma cell lines (U87, U563, and U251N), primary cultures of human fetal astrocytes, as well as adult and fetal human brain cDNA were used. Previously described Cav3.1 splice variants were present in glioma samples, cultured cells and whole brain. Consistent with the literature, our results reveal that in the normal adult brain, Cav3.1a transcripts predominate, while Cav3.1b is mostly fetal-specific. RT-PCR results on glioma and glioma cell lines showed that Cav3.1 expression in tumor cells resemble fetal brain expression pattern as Cav3.1bc is predominantly expressed. In addition, we identified a novel splice variant, Cav3.1ac, expressed in three glioma biopsies and one glioma cell line, but not in normal brain or fetal astrocytes. Transient expression of this variant demonstrates that Cav3.1ac displays similar current-voltage and steady-state inactivation properties compared with Cav3.1b, but a slower recovery from inactivation. Taken together, our data suggest glioma-specific Cav3.1 gene regulation, which could possibly contribute to tumor pathogenesis. © 2004 Wiley-Liss, Inc. [source] Effects of prolactin on intracellular calcium concentration and cell proliferation in human glioma cellsGLIA, Issue 3 2002Thomas Ducret Abstract Prolactin (PRL) has several physiological effects on peripheral tissues and the brain. This hormone acts via its membrane receptor (PRL-R) to induce cell differentiation or proliferation. Using reverse transcription,polymerase chain reaction (RT-PCR) combined with Southern blot analysis, we detected PRL-R transcripts in a human glioma cell line (U87-MG) and in primary cultured human glioblastoma cells. These transcripts were deleted or not in their extracellular domains. We examined the effects of PRL on intracellular free Ca2+ concentration ([Ca2+]i) in these cells in order to improve our understanding of the PRL transduction mechanism, which is still poorly documented. [Ca2+]i was measured by microspectrofluorimetry using indo-1 as the Ca2+ fluorescent probe. Spatiotemporal aspects of PRL-induced Ca2+ signals were investigated using high-speed fluo-3 confocal imaging. We found that physiological concentrations (0.4,4 nM) of PRL-stimulated Ca2+ entry and intracellular Ca2+ mobilization via a tyrosine kinase,dependent mechanism. The two types of Ca2+ responses observed were distinguishable by their kinetics: one showing a slow (type I) and the other a fast (type II) increase in [Ca2+]i. The amplitude of PRL-induced Ca2+ increases may be sufficient to provoke several physiological responses, such as stimulating proliferation. Furthermore, PRL induced a dose-dependent increase in [3H]thymidine incorporation levels and in cellular growth and survival, detected by the MTT method. These data indicate that PRL induced mitogenesis of human glioma cells. GLIA 38:200,214, 2002. © 2002 Wiley-Liss, Inc. [source] Dominant-negative Rac increases both inherent and ionizing radiation-induced cell migration in C6 rat glioma cellsINTERNATIONAL JOURNAL OF CANCER, Issue 8 2006So-Young Hwang Abstract Rho-like GTPases, including Cdc42, Rac1 and RhoA, regulate distinct actin cytoskeleton changes required for cell adhesion, migration and invasion. In the present study, we examined the role of Rac signaling in inherent migration, as well as radiation-induced migration, of rat glioma cells. Stable overexpression of dominant-negative Rac1N17 in a C6 rat glioma cell line (C6-RacN17) promoted cell migration, and ionizing radiation further increased this migration. Migration was accompanied by decreased expression of the focal adhesion molecules FAK and paxillin. Focal contacts and actin stress fibers were also reduced in C6-RacN17 cells. Downstream effectors of Rac include JNK and p38 MAP kinases. Irradiation transiently activated p38, JNK and ERK1/2 MAP kinases in C6-RacN17 cells, while p38 and JNK were constitutively activated in C6 control cells. Blocking JNK activity with JNK inhibitor SP600125 inhibited migration, suggesting that the JNK pathway may regulate radiation-induced, as well as inherent, migration of C6-RacN17 cells. Additionally, the radiation-induced migration increase was also inhibited by SB203580, a specific inhibitor of p38 MAP kinase. However, PD98059, a MEK kinase 1 inhibitor, failed to influence migration. This is the first evidence that suppression of Rac signaling may be involved in invasion or metastasis of glioma cells before and/or after radiotherapy. These data further suggest that radiotherapy for malignant glioma needs to be used with caution because of the potential for therapy-induced cell migration or invasion and that pharmacological inhibition of cell migration and invasion through targeting the Rac signaling pathway may represent a new approach for improving the therapeutic efficacy of radiotherapy for malignant glioma. © 2005 Wiley-Liss, Inc. [source] RNAi-mediated inhibition of MSP58 decreases tumour growth, migration and invasion in a human glioma cell lineJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 11-12 2009Wei Lin Abstract MSP58, a 58-kD nuclear microspherule protein, is an evolutionarily conserved nuclear protein implicated in the regulation of gene transcription as well as in malignant transformation. An analysis of mRNA expression by real-time PCR revealed that MSP58 was significantly up-regulated in 29% of high-grade glioblastoma tissues as well as in four glioblastoma cell lines. In the present study, we further evaluated the biological functions of MSP58 in U251 glioma cell proliferation, migration, invasion and tumour growth in vivo by specific MSP58 knockdown using short hairpin RNA (shRNA). We found that MSP58 depletion inhibited glioma cell growth, primarily by inducing cell cycle arrest rather than apoptosis. MSP58 depletion also decreased the invasive capability of glioma cells and anchorage-independent colony formation in soft agar. Moreover, suppression of MSP58 expression significantly impaired the growth of glioma xenografts in nude mice. Finally, a cell cycle-associated gene array revealed potential molecular mechanisms contributing to cell cycle arrest in MSP58-depleted glioma cells. In summary, our data highlight the importance of MSP58 in glioma progression and provided a biological basis for MSP58 as a novel candidate target for treatment of glioma. [source] Ultrastructural characterization of the new NG97ht human-derived glioma cell line using two different electron microscopy technical proceduresMICROSCOPY RESEARCH AND TECHNIQUE, Issue 4 2009Camila Maria Longo Machado Abstract On the basis of transmission electron microscopy observations in tumor cell lines, oncologists have made innumerous diagnostic and therapeutical progresses. Following this path, the UNICAMP immunopathologies laboratory established the NG97 cell line derived from a human astrocytoma grade III, which when injected to the athymic nude mouse flank developed a grade IV astrocytoma. In this study, we focused on ultrastructural characterization of the NG97 cells after being recovered from xenotransplant (NG97ht). These cells in culture were assayed by two different electron microscopy procedures to characterize ultrastructures related to grade IV astrocytomas and to observe their structures through cell subcultivation. Additionally, comparative morphological descriptions of different cell passages in these technical procedures could be a useful tool for improving electron microscopy cell lineage protocols. Results from many cell passage observations showed ultrastructural similarities, which suggest malignant and glioblastoma phenotypes. In the first procedure, NG97ht cells were harvested and then incorporated into agarose before subjecting them to electron microscopy protocols, whereas in the second one, monolayer cells grew first on cover slides. Comparison among protocols revealed that organelles, cytoplasmatic extensions, spatial conformation of filopodia, and cell attachment to substrate were more preserved in the second procedure. Furthermore, in this latter procedure, a unique ellipsoidal structure was observed, which was already described when dealing with gliosarcoma cell line elsewhere. Therefore, these analyses demonstrated a morphological characterization of a new NG97ht cell line using electron transmission microscopy. Moreover, it has been shown that the second procedure provides more detailed information compared with the first. Microsc. Res. Tech, 2009. © 2008 Wiley-Liss, Inc. [source] GABAA -receptor expression in glioma cells is triggered by contact with neuronal cellsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2001Michael Synowitz Abstract The expression of functional GABAA -receptors in glioma cells correlates with low malignancy of tumours and cell lines from glioma lack these receptors. Here we show that contact with neurons induces the expression of functional GABAA -receptors. C6 and F98 glioma cell lines were labelled by recombinant expression of enhanced green fluorescent protein injected into rat brain and studied in acute slices after two to three weeks of tumour growth. The cells responded to GABA or the specific agonist, muscimol with a current typical for GABAA -receptors, as studied with the patch-clamp technique. To get insight into the mechanism of GABAA receptor induction, the C6 or F98 cells were co-cultured with neurons, astrocytes, oligodendrocytes and microglia. Glioma cells expressed functional GABAA receptors within 24 h only in cultures where physical contact to neurons occurred. Activation of GABAA -receptors in the co-cultures attenuated glioma cell metabolism while blockade of the receptors increased metabolism. We conclude that with this form of interaction, neurons can influence tumour behaviour in the brain. [source] Characterization and gene expression profiling in glioma cell lines with deletion of chromosome 19 before and after microcell-mediated restoration of normal human chromosome 19GENES, CHROMOSOMES AND CANCER, Issue 10 2009Kristen L. Drucker Nearly 10% of human gliomas are oligodendrogliomas. Deletion of chromosome arm 19q, often in conjunction with deletion of 1p, has been observed in 65,80% of these tumors. This has suggested the presence of a tumor suppressor gene located on the 19q arm. Chromosome 19 deletion is also of interest due to the better prognosis of patients with deletion, including longer survival and better response to chemotherapy, compared with patients without deletion. Two glioma cell lines with deletion of 19q were used for chromosome 19 microcell-mediated transfer, to assess the effect of replacing the deleted segment. Complementation with chromosome 19 significantly reduced the growth rate of the hybrid cells compared with the parental cell lines. Affymetrix U133 Plus 2.0 Gene Chip analysis was performed to measure and compare the expression of the chromosome 19 genes in the chromosome 19 hybrid cell lines to the parental cell line. Probes were considered significantly different when a P value <0.01 was seen in all of the cell line comparisons. Of 345 probes within the commonly deleted 19q region, seven genes (APOE, RCN3, FLJ10781, SAE1, STRN4, CCDC8, and BCL2L12) were identified as potential candidate genes. RT-PCR analysis of primary tumor specimens showed that several genes had significant differences when stratified by tumor morphology or deletion status. This suggests that one or more of these candidates may play a role in glioma formation or progression. © 2009 Wiley-Liss, Inc. [source] Elastin-derived peptides: Matrikines critical for glioblastoma cell aggressiveness in a 3-D systemGLIA, Issue 16 2009Bérénice Coquerel Abstract In the most common primary brain tumors, malignant glioma cells invade the extracellular matrix (ECM) and proliferate rapidly in the cerebral tissue, which is mainly composed of hyaluronan (HA) along with the elastin present in the basement membrane of blood vessels. To determine the role of ECM components in the invasive capacity of glioma cell lines, we developed a 3-D cell-culture system, based on a hydrogel in which HA can be coreticulated with kappa-elastin (HA-,E). Using this system, the invasiveness of cells from four glioma cell lines was dramatically increased by the presence of ,E and a related, specific peptide (VGVAPG)3. In addition, MMP-2 secretion increased and MMP-12 synthesis occurred. Extracellular injections of ,E or (VGVAPG)3 provoked a pronounced and dose-dependent increase in [Ca2+]i. ,E significantly enhanced the expression of the genes encoding elastin-receptor and tropoelastin. We propose the existence of a positive feedback loop in which degradation of elastin generates fragments that stimulate synthesis of tropoelastin followed by further degradation as well as migration and proliferation of the very cells responsible for degradation. All steps in this ECM-based loop could be blocked by the addition of either of the EBP antagonists, lactose, and V-14 peptide, suggesting that the loop itself should be considered as a new therapeutic target. © 2009 Wiley-Liss, Inc. [source] HSP27 mediates SPARC-induced changes in glioma morphology, migration, and invasionGLIA, Issue 10 2008William A. Golembieski Abstract Secreted protein acidic and rich in cysteine (SPARC) regulates cell,extracellular matrix interactions that influence cell adhesion and migration. We have demonstrated that SPARC is highly expressed in human gliomas, and it promotes brain tumor invasion in vitro and in vivo. To further our understanding regarding SPARC function in glioma migration, we transfected SPARC-green fluorescent protein (GFP) and control GFP vectors into U87MG cells, and assessed the effects of SPARC on cell morphology, migration, and invasion after 24 h. The expression of SPARC was associated with elongated cell morphology, and increased migration and invasion. The effects of SPARC on downstream signaling were assessed from 0 to 6 h and 24 h. SPARC increased the levels of total and phosphorylated HSP27; the latter was preceded by activation of p38 MAPK and inhibited by the p38 MAPK inhibitor SB203580. Augmented expression of SPARC was correlated with increased levels of HSP27 mRNA. In a panel of glioma cell lines, increasing levels of SPARC correlated with increasing total and phosphorylated HSP27. SPARC and HSP27 were colocalized to invading cells in vivo. Inhibition of HSP27 mRNA reversed the SPARC-induced changes in cell morphology, migration, and invasion in vitro. These data indicate that HSP27, a protein that regulates actin polymerization, cell contraction, and migration, is a novel downstream effector of SPARC-regulated cell morphology and migration. As such, it is a potential therapeutic target to inhibit SPARC-induced glioma invasion. © 2008 Wiley-Liss, Inc. [source] Expression of T-type calcium channel splice variants in human gliomaGLIA, Issue 2 2004Isabelle Latour Abstract In humans, three isoforms of the T-type (Cav3.1) calcium-channel ,1 subunit have been reported as a result of alternate splicing of exons 25 and 26 in the III,IV linker region (Cav3.1a, Cav3.1b or Cav3.1bc). In the present study, we report that human glioma express Cav3.1 channels in situ, that splicing of these exons is uniquely regulated and that there is expression of a glioma-specific novel T-type variant (Cav3.1ac). Seven human glioma samples were collected at surgery, RNA was extracted, and cDNA was produced for RT-PCR analysis. In addition, three glioma cell lines (U87, U563, and U251N), primary cultures of human fetal astrocytes, as well as adult and fetal human brain cDNA were used. Previously described Cav3.1 splice variants were present in glioma samples, cultured cells and whole brain. Consistent with the literature, our results reveal that in the normal adult brain, Cav3.1a transcripts predominate, while Cav3.1b is mostly fetal-specific. RT-PCR results on glioma and glioma cell lines showed that Cav3.1 expression in tumor cells resemble fetal brain expression pattern as Cav3.1bc is predominantly expressed. In addition, we identified a novel splice variant, Cav3.1ac, expressed in three glioma biopsies and one glioma cell line, but not in normal brain or fetal astrocytes. Transient expression of this variant demonstrates that Cav3.1ac displays similar current-voltage and steady-state inactivation properties compared with Cav3.1b, but a slower recovery from inactivation. Taken together, our data suggest glioma-specific Cav3.1 gene regulation, which could possibly contribute to tumor pathogenesis. © 2004 Wiley-Liss, Inc. [source] MicroRNA-10b is overexpressed in malignant glioma and associated with tumor invasive factors, uPAR and RhoCINTERNATIONAL JOURNAL OF CANCER, Issue 6 2009Takashi Sasayama Abstract MicroRNAs (miRNAs) are effective post-transcriptional regulators of gene expression and are important in many biological processes. Although the oncogenic and tumor suppressive functions of several miRNAs have been characterized, the role of miRNAs in mediating tumor invasion and migration remains largely unexplored. Recently, miR-10b was identified as an miRNA highly expressed in metastatic breast cancer, promoting cell migration and invasion. Here, we performed real-time reverse transcriptase polymerase chain reaction (RT-PCR) assays on 43 glioma samples (17 glioblastoma, 6 anaplastic astrocytoma, 10 low-grade astrocytoma, 6 oligodendroglioma and 4 ependymoma) and 6 glioma cell lines. We found that miR-10b expression was upregulated in all glioma samples compared to non-neoplastic brain tissues. The expression levels of miR-10b were associated with higher grade glioma. In addition, mRNA expressions of RhoC and urokinase-type plasminogen activator receptor (uPAR), which were thought to be regulated by miR-10b via HOXD10, were statistically significantly correlated with the expression of miR-10b (p < 0.001, p = 0.001, respectively). Also, protein expression levels of RhoC and uPAR were associated with expression levels of miR-10b (p = 0.009, p = 0.014, respectively). Finally, multifocal lesions on enhanced MRI of 7 malignant gliomas were associated with higher expression levels of miR-10b (p = 0.02). Our data indicated that miR-10b might play some role in the invasion of glioma cells. © 2009 UICC [source] Inhibition of immunosuppressive effects of melanoma-inhibiting activity (MIA) by antisense techniquesINTERNATIONAL JOURNAL OF CANCER, Issue 1 2005Piotr Jachimczak Abstract Melanoma inhibitory activity (MIA) is an 11 kD protein secreted by malignant melanomas. Recent studies revealed an interaction of MIA with epitopes of extracellular matrix proteins including fibronectin. Structural homology of MIA with the binding sites of ,4,1 integrin results in complex interactions of MIA with molecules binding to ,4,1 integrin. As cells of the immune system express ,4,1 integrins (VLA-4), we investigated whether MIA may modulate the function of human leukocytes. Here we describe the effects of MIA on the activation of human PBMCs and auto-/allogeneic lymphokine-activated killer cell (LAK) cytotoxicity in human MIA-negative glioma cell lines and MIA-positive melanoma cell lines in vitro. MIA inhibits PHA- or IL-2-induced human PBMC proliferation in a dose-dependent manner up to 63% (3H-Tdr incorporation) and 59% (cell count), respectively, when added to the cell culture prior to mitogen stimulation. In addition, both autologous (GL and HW) and allogeneic (HTZ-17, HTZ-243 and HTZ-374) antitumor LAK cytotoxicity was reduced by the addition of exogenous rhMIA (500 ng/ml, f.c.). Consequently, endogenous inhibition of MIA expression in human melanoma cells by MIA-specific phosphorothioate antisense oligonucleotides enhanced the autologous LAK-cell activity to the same level as observed in MIA-negative human HMB melanoma cells expressing an MIA-antisense construct. Our results indicate that MIA may contribute to immunosuppression frequently seen in malignant melanomas by inhibiting cellular antitumor immune reactions. Antagonization of MIA activity using antisense techniques may represent a novel therapeutic strategy for treatment of malignant melanomas. [source] Pleiotrophin, an angiogenic and mitogenic growth factor, is expressed in human gliomasJOURNAL OF NEUROCHEMISTRY, Issue 4 2002Rolf Mentlein Abstract Pleiotrophin (PTN) is a mitogenic/angiogenic, 15.3 kDa heparin-binding peptide that is found in embryonic or early postnatal, but rarely in adult, tissues. Since developmentally regulated factors often re-appear in malignant cells, we examined PTN expression in human glioma cell lines, cell cultures derived from solid gliomas and glioma sections. PTN mRNA or protein was detected by reverse transcriptase-polymerase chain reaction, immunohistochemistry, western blot or enzyme-linked immunoassay in all WHO III and IV grade gliomas and cells analyzed in vitro or in situ. One WHO II grade glioma investigated was PTN negative. In vitro, PTN was synthesized in perinuclear regions of glioma cells, secreted into the cultivation medium, but its production varied considerably between glioma cells cultivated from different solid gliomas or glioma cell lines. In situ, PTN expression was restricted to distinct parts/cells of the tumour. PTN did not influence the proliferation of glioma cells themselves, but stimulated [3H]thymidine incorporation into DNA of microglial cells. Furthermore, in Boyden chamber assays, PTN showed a strong chemotactic effect on murine BV-2 microglial cells. PTN is supposed to be a paracrine growth/angiogenic factor that is produced by gliomas and contributes to their malignancy by targeting endothelial and microglial cells. [source] Cooperative inhibitory effect of ZD1839 (Iressa) in combination with 17-AAG on glioma cell growth,MOLECULAR CARCINOGENESIS, Issue 5 2006Daniel R. Premkumar Abstract ZD1839 ("Iressa") is an orally active, selective epidermal growth factor (EGF) receptor-tyrosine kinase inhibitor. We evaluated the antitumor activity of ZD1839 in combination with HSP90 antagonist, 17-AAG in malignant human glioma cell lines. ZD1839 independently produced a dose-dependent inhibition of cellular proliferation in glioma cells grown in culture with time- and dose-dependent accumulation of cells in G1 phase of the cell cycle on flow cytometric analysis, although the concentrations required for optimal efficacy were at or above the limits of clinically achievable levels. Because the heat shock protein (HSP) is involved in the conformational maturation of a number of signaling proteins critical to the proliferation of malignant glioma cells, we hypothesized that the HSP90 inhibitor 17-AAG would potentiate ZD 1839-mediated glioma cytotoxicity by decreasing the activation status of EGF receptor, as well as downregulating the levels of other relevant signaling effectors. We, therefore, examined the effects of ZD1839 and 17-AAG, alone and in combination, on signal transduction and apoptosis in a series of malignant glioma cell lines. Simultaneous exposure to these inhibitors significantly induced cell death and quantitative analysis revealed that interaction between ZD1839 and 17-AAG-induced cytotoxicity was synergistic, leading to a pronounced increase in active caspase-3 and PARP cleavage. No significant growth inhibition or caspase activation was seen in control cells. The enhanced cytotoxicity of this combination was associated with diminished Akt activation and a significant downregulation of EGFR receptor, Raf-1 and mitogen activated protein kinase (MAPK). Cells exposed to 17-AAG and ZD1839 displayed a significant reduction in cell cycle regulatory proteins, such as CDK4 and CDK6. Taken together, these findings suggest that ZD1839, an EGF receptor tyrosine kinase inhibitor, plays a critical role in regulating the apoptotic response to 17-AAG and that multi-site targeting of growth signaling and cell survival pathways could provide a potent strategy to treat patients with malignant gliomas. © 2006 Wiley-Liss, Inc. [source] Correlation of thrombospondin-1 and transforming growth factor-, expression with malignancy of gliomaNEUROPATHOLOGY, Issue 3 2000Tomoyuki Kawataki The expression of thrombospondin-1 (TSP-1) and its role in gliomas have not been well examined. In the present study TSP-1 expression in a panel of malignant glioma cell lines and the expression of TSP-1 and transforming growth factor (TGF-,) proteins in low-grade and malignant glioma tissues were investigated. Reverse transcription-polymerase chain reaction analysis showed that nine of nine malignant glioma cell lines expressed TSP-1 mRNA, and seven of nine glioma lines expressed TSP-2 mRNA. Production and secretion of TSP-1 were examined in the T98G glioblastoma cell line by western blot analysis. Total TSP-1 protein content in the supernatant was 10 times higher than that in the cell lysate. Secretion of TSP-1 was examined in these glioma cell lines by western blot analysis. All glioma lines secreted significant levels of TSP-1. Bioassay showed that all tumor lines had the capacity to activate latent TGF-,. Localization of TSP-1, TGF-,1, -,2, and -,3 was examined immunohistochemically in surgically resected glioma tissues, including 11 glioblastomas, six anaplastic astrocytomas, and eight astrocytomas. Most glioblastomas expressed high levels of both TSP-1 and TGF-,. Anaplastic astrocytomas expressed moderate levels of TSP-1 and TGF-,. Most malignant gliomas expressed various levels of TGF-,1, -,2, and -,3. The expression of both proteins, however, was weak in low-grade gliomas. Normal brain tissues around the tumors were negatively or very weakly positively stained for TSP-1 and TGF-,. These results indicate that most malignant glioma cells express TSP-1 in vitro and in vivo, and the expression of TSP-1 and TGF-,in vivo correlates with the histologic malignancy of glioma. Overexpression of both TSP-1 and TGF-, may increase the biologic malignancy of malignant gliomas, through generating the active form of TGF-, in tumor tissues. [source] Vesicle amine transport protein-1 (VAT-1) is upregulated in glioblastomas and promotes migrationNEUROPATHOLOGY & APPLIED NEUROBIOLOGY, Issue 4 2009S. Mertsch Aim:,Diffuse invasion of single-glioma cells is the main obstacle to successful therapy of these tumours. After identifying vesicle amine transport protein-1 (VAT-1) as being upregulated in invasive human gliomas, we study its possible function in glioblastoma cell migration. Methods:,Based on data obtained from previous oligonucleotide arrays, we investigated expression of VAT-1 in glioblastoma tissue and cell lines on mRNA levels using reverse transcriptase PCR. Furthermore, we examined the amount and localization of VAT-1 protein using immunoblotting and immunohistochemistry. Using small interfering RNA technology we repressed VAT-1 expression in human glioma cell lines and analysed their migration using wound healing and transwell migration assays. Results:,Increased VAT-1 mRNA and protein levels were found in glioblastoma tissues and cell lines compared with normal human brain. Small interfering RNA-mediated VAT-1 knockdown led to significantly reduced migration of human glioma cells. Conclusions:,VAT-1 is overexpressed in glioblastomas and functionally involved in glioma cell migration, representing a new component involved in glioma invasion. [source] Photodynamic effect of hypericin in primary cultures of human umbilical endothelial cells and glioma cell linesPHYTOTHERAPY RESEARCH, Issue 6 2009Viktória Stupáková Abstract Hypericin is the most powerful naturally occurring photosensitizer and as such there is renaissant interest in the potentials of this compound for anticancer photodynamic therapy (PDT). The purpose of this study was to investigate the hypericin-mediated photodynamic therapy effects on normal human umbilical endothelial cells (HUVECs) in comparison with cancer human glioma cell lines U-87 MG and U-373 MG, in in vitro conditions. The data suggest that endothelial cells as well as glioma cell lines are sensitive only to photoactivated hypericin. The inhibitory effects of photoactivated hypericin did not differ in endothelial compared with tumor cells in cytotoxicity MTT and DNA fragmentation assays. However, an important difference in sensitivity was found between the above mentioned cell types in migration and metalloproteinases inhibition assays performed as cell function tests. The findings in both function tests were supported by the high sensitivity of endothelial cells in an additional angiogenesis test of tubular formation in vitro. Copyright © 2009 John Wiley & Sons, Ltd. [source] RASSF1A, BLU, NORE1A, PTEN and MGMT Expression and Promoter Methylation in Gliomas and Glioma Cell Lines and Evidence of Deregulated Expression of de novo DNMTsBRAIN PATHOLOGY, Issue 2 2009Aiala Lorente Abstract Methylation of CpG islands in gene promoters can lead to gene silencing. Together with deletion or mutation, it may cause a loss of function of tumor suppressor genes. RASSF1A (3p21.3), NORE1A (1q32.1) and BLU (3p21.3) have been shown to be downregulated by methylation in cancer, and PTEN (10q23.3) and MGMT (10q26.1) are located in areas commonly deleted in astrocytomas. MGMT methylation predicts a better response and a longer overall survival in patients with glioblastomas treated with temozolomide. We analyzed 53 astrocytoma samples and 10 high-grade glioma cell lines. Gene expression was assessed by RT-PCR. Bisulfite sequencing, MSP and a melting curve analysis-based real-time PCR were performed to detect promoter methylation. Treatments with 5,-aza-2,-deoxicitidine were applied to restore gene expression in cell lines. Ninety-two percent of tumor samples were methylated for RASSF1A, 30%,57% for BLU and 47% for MGMT, suggesting promoter methylation of these genes to be a common event in glioma tumorigenesis. Only 4% of the tumors revealed a methylated promoter for NORE1A. No association between methylation and loss of expression could be established for PTEN. We identified de novo DNMTs overexpression in a subset of tumors which may explain the methylation phenotype of individual gliomas. [source] CD95-mediated Apoptosis of Human Glioma Cells: Modulation by Epidermal Growth Factor Receptor ActivityBRAIN PATHOLOGY, Issue 1 2002Joachim P. Steinbach The death ligands CD95L and Apo2L/TRAIL are promising investigational agents for the treatment of malignant glioma. EGFR is overexpressed in a significant proportion of malignant gliomas in vivo. Here, we report that CD95L-induced cell death is enhanced by EGFR inhibition using tyrphostine AG1478 in 7 of 12 human malignant glioma cell lines. Conversely, CD95-mediated and Apo2L-induced cell death are both inhibited by overexpression of EGFR in LN-229 cells. CD95L-induced cell death augmented by AG1478 is accompanied by enhanced processing of caspase 8. LN-229 cells overexpressing the viral caspase inhibitor, crm-A, are not sensitized to CD95L-induced cell death by AG1478, indicating that EGFR exerts its antiapoptotic properties through a caspase 8-dependent pathway. These data define a modulatory effect of EGFR-activity on death ligand-induced apoptosis and indicate that EGFR inhibition is likely to improve the efficacy of death ligand-based cancer therapies. Furthermore, it is tempting to speculate that EGFR amplification protects tumor cells from death ligand-mediated host immune responses in vivo and that EGFR's effects on death receptor-mediated apoptosis may explain the anti-tumor effects of non-cytotoxic, unarmed anti-EGFR family antibodies. [source] Inhibition of tumor-induced edema by antisense VEGF is mediated by suppressive vesiculo-vacuolar organelles (VVO) formationCANCER SCIENCE, Issue 12 2008Zhi Xiong Lin Vascular endothelial growth factor (VEGF) is an important regulator of angiogenesis, vasculogenesis and vascular permeability. Edema in glioma tumors is considered one of the most pathological characteristics, but the mechanism of regulating vascular permeability is still unclear. In the present study, tumorigenic mice were generated by subcutaneous injection of glioma cell lines, C6-null cells and stable transfected-C6 cells overexpressing mock vector (C6-mock) and antisense VEGF (C6-VEGF,/,). Overexpression of antisense VEGF (C6-VEGF,/, mice) significantly suppressed tumor growth, decreased angiogenesis and reduced tumoral edema. Further studies by electron microscope revealed that tumor-induced hyperpermeability was mediated by formation of vesiculo-vacuolar organelles (VVO), specifically reducing the number of vesicle and caveolae in VVO, and this effect was blocked, at least partially, by antisense VEGF. These data show a possible mechanism of tumor-induced hyperpermeability and indicate that blockage of VEGF might contribute to therapeutical strategies for tumor edema. (Cancer Sci 2008; 99: 2540,2546) [source] | |||||||||||||||||||||||||