UMLS:C0017636 - FACTA Search

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Query: UMLS:C0017636 (glioblastoma)
18,345 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glioblastomas, the most malignant and prevalent brain tumors which remain incurable, are characterized by both extensive proliferation and invasive growth. We previously reported a remarkable antitumoral effect of the retinoid 6-OH-11-O-hydroxyphenantrene (IIF) on neuroblastoma, leukemia and colon carcinoma cells. In this study we examined the effect of IIF on proliferation, apoptosis and cell invasion in the human glioblastoma cell line U87MG, in comparison with all-trans-retinoic acid (RA). Our results showed that both retinoids induced cell growth inhibition and apoptosis in a dose- and time-dependent manner. We also demonstrated that the invasive ability of glioblastoma cells decreased after treatment with IIF or RA. Since cell invasion involves a complex system of tightly regulated proteases, matrix metalloproteinases (MMPs) and their specific inhibitors, tissue inhibitors of MMPs (TIMPs), we analysed the effect of IIF on MMP and TIMP expression in comparison with RA. Treatment with both retinoids resulted in a marked decrease of MMP2 and MMP9 expression and of lytic activity of MMP2. In addition, exposure to IIF led to enhanced expression of TIMP2. Collectively, our results demonstrated the effectiveness of both IIF and RA in inhibiting proliferation, cell migration, and the invasive potential of glioblastoma U87MG cells. Notably, the anticancer activity of IIF, on the whole, was more pronounced than that of RA. Therefore, these findings, besides providing further evidence that IIF may be a powerful tool in the development of cancer treatments, suggest that IIF may have therapeutic potential against the invasiveness of brain tumors.
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PMID:Inhibitory effects of retinoic acid and IIF on growth, migration and invasiveness in the U87MG human glioblastoma cell line. 1778 68

Extracellular matrix metalloproteinase inducer (EMMPRIN), a member of the immunoglobulin superfamily, is present on the surface of tumor cells where it stimulates adjacent fibroblasts to produce matrix metalloproteinases (MMPs). We have analyzed the clinicopathological characteristics of EMMPRIN and MMP2 expression in normal brain tissue and pediatric gliomas and evaluated their prognostic value in diagnosing the latter. Immunochemistry analysis revealed EMMPRIN and MMP2 expression in cryo-sections of pediatric gliomas (45 samples) and normal brain tissue (20 samples). Both EMMPRIN and MMP2 were expressed in normal brain and glioma tissues with different levels of malignancy. The intensively positive expression rates of EMMPRIN (22/27) and MMP2 (21/27) in anaplastic astrocytoma and glioblastoma tissues were significantly higher than those in normal brain and low-grade astrocytoma tissues (2/28 and (1/2)8, respectively). Spearman analysis indicated that the expression level of EMMPRIN was significantly positively correlated with that of MMP2 (r = 0.86, p < 0.01). The positive expression of EMMPRIN and MMP2 was associated with higher grade gliomas. Patients with EMMPRIN+/MMP2+ expression had the lowest survival rate (p < 0.01). Based on these results, we conclude that EMMPRIN and MMP2 are expressed differently in normal brain and pediatric gliomas. The detection of their co-expression may facilitate the prediction of pediatric gliomas prognosis.
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PMID:Clinical implications and prognostic value of EMMPRIN/CD147 and MMP2 expression in pediatric gliomas. 1879 27

A recent systematic analysis of 18.191 well annotated coding sequences (RefSeq) in breast and colorectal cancers has led to the identification of somatic mutations in 1.718 genes (Wood et al., 2007). Based on statistical parameters 280 of these have been denominated candidate cancer (CAN) genes. This analysis has provided an interesting snapshot of the landscape of tumor genomes by showing that they contain a few frequently mutated genes (denominated 'mountains'). On the contrary, the large majority of CAN genes are altered at low frequency (designated 'hills'). Whether 'hill' type CAN genes are tumor specific is largely unknown. To address this question we evaluated the mutational profiles of 27 'hill' CAN genes in glioblastoma, melanoma and pancreatic carcinoma by sequencing the exons previously found mutated by Wood and colleagues. Only 4 of the breast/colorectal 'hill' type CAN genes (SMAD4, MYO18B, NAV3 and MMP2) were also mutated in melanoma and pancreatic carcinoma, while none was altered in glioblastoma. These results suggest that 'hill' type CAN genes are not frequently shared by different tumor types and that their mutation patterns are tissue specific. Tumor-specific genome wide mutational profiling will be required to identify 'hill' type CAN genes that characterize the genomic landscapes of each cancer lineage.
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PMID:Mutational profiling of cancer candidate genes in glioblastoma, melanoma and pancreatic carcinoma reveals a snapshot of their genomic landscapes. 1905 23

Experimental data from in vitro and in vivo models indicate that peroxisome proliferator-activated receptor (PPAR) ligand activation regulates differentiation and induces cell growth arrest and apoptosis in a variety of cancer types. Thiazolidinediones such as ciglitazone (CGZ) constitute the most well-known synthetic ligands for PPARgamma. We previously reported a remarkable antitumor effect of the retinoid 6-OH-11-O-hydroxyphenantrene (IIF), synthetic retinoid X receptors (RXRs) agonist, on many cancer cell lines. Since PPARs bind to DNA as heterodimers with RXRs, in this study we investigated if IIF potentiates the antitumoral properties of the PPARgamma ligand CGZ in glioblastoma U87MG and melanoma G361 cells. Our results show that either IIF or CGZ inhibited cell growth and tissue invasion ability, but these properties were enhanced by using IIF and CGZ in combined treatment. Since matrix metalloproteinases (MMPs) play a major role in tumor cell invasion, we analyzed the effect of IIF and CGZ on MMP2 and MMP9 activity and expression. The addition of IIF to CGZ resulted in a decrease of MMP2 and MMP9 expression and activity, higher than when each agent was used alone. Furthermore, treatment with IIF and/or CGZ enhanced PPARgamma expression but both agents in combined treatment caused the maximum efficiency. Finally, we demonstrated that IIF can potentiate PPARgamma trascriptional activity induced by CGZ, by evaluation of peroxisome proliferator-responsive element transactivation. In conclusion, these findings suggest that the RXR selective retinoid IIF, in combination with the PPARgamma ligand CGZ, may provide a therapeutic advantage in cancer treatment.
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PMID:Enhanced effects of PPARgamma ligands and RXR selective retinoids in combination to inhibit migration and invasiveness in cancer cells. 1928 12

We reported that PAX6 suppresses glioblastoma cell growth in vivo and anchorage-independent growth without significant alteration of cell proliferation in vitro, suggesting that PAX6 may alter the tumor microenvironment. Because we found that PAX6 downregulates expression of the gene encoding vascular endothelial growth factor A (VEGFA) in glioma cells, we used a subcutaneous xenograft model to verify PAX6 suppression of VEGFA-induced angiogenesis based on CD31-immunostaining of endothelial cells. The results showed a significant reduction of VEGFA at the transcription level in PAX6-transfected cells in xenografts and PAX6 has a suppressive effect on the microvascular amplification typically seen in glioblastoma. We showed that PAX6 suppression of VEGFA expression requires its DNA binding-domain. The C-terminal truncation mutant of PAX6, however, did not show the dominant negative function in regulating VEGFA expression that it showed previously in regulating MMP2 expression. In the glioma cell line U251HF, we further determined that blocking the PI3K/Akt signaling pathway with either adenoviral-mediated PTEN expression or LY294002 enhanced PAX6-mediated suppression of VEGFA in an additive manner; thus, PAX6-mediated suppression of VEGFA is not via the canonical pathway through HIF1A. These two VEGFA-regulatory pathways can also be similarly modulated in another malignant glioma cell line, U87, but not in LN229 where the basal VEGFA level is low and PTEN is wild-type. PAX6 suppression of VEGFA appears to be blocked in LN229. In conclusion, our data showed that PAX6 can initiate in glioma cells a new signaling pathway independent of PI3K/Akt-HIF1A signaling to suppress VEGFA expression.
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PMID:PAX6 suppression of glioma angiogenesis and the expression of vascular endothelial growth factor A. 1961 19

In contrast to pilocytic astrocytomas (WHO grade I gliomas) that are circumscribed and cured by surgical resection, invasion is a hallmark of grades II-IV gliomas. Proteases play a major role in the invasion process and correlations between glioma grading, survival and protease expression have been demonstrated. In this study, we have chosen to study using different technical approaches (Q-RT-PCR, in situ hybridization and immunohistochemistry) the expression of five molecules involved in extracellular matrix degradation (cathepsin B, MMP2, MMP9, uPA and PAI-1) in glioblastomas in order to determine their prognostic impact among grade IV gliomas. Pilocytic astrocytomas were used as controls. Q-RT-PCR showed that transcripts of uPA, PAI-1, cathepsin B and MMP9 were significantly more expressed in glioblastomas (n = 52), in comparison to pilocytic astrocytomas (n = 17) (P = 0.049, P < 0.0001, P = 0.03 and P < 0.0001, respectively). On both univariate and multivariate analyses, cathepsin B and PAI-1 were strong predictors of overall survival among the group of glioblastomas (P < 0.0001 and P = 0.01, respectively). Immunohistochemical expression of cathepsin B further confirmed its prognostic value in an independent cohort of patients with glioblastoma. In situ hybridization showed that uPA is detected at the invasive edge of glioblastomas, whereas PAI-1 is more abundant in microvascular proliferation and pseudo-palisading cells than at the infiltrative edges. These results suggest that cathepsin B and PAI-1 are important biomarkers for the stratification of glioblastoma patients with respect to survival.
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PMID:High expression of cathepsin B and plasminogen activator inhibitor type-1 are strong predictors of survival in glioblastomas. 1977 87

Polyamidoamine (PAMAM) dendrimer and Tat peptides were conjugated to bacterial magnetic nanoparticles (BMPs) for the construction of an efficient and targeted gene delivery system with transmembrane ability for the gene therapy of brain tumors. Tat-BMPs-PAMAM was complexed with small interfering RNA expression plasmid (psiRNA) corresponding to the open reading frame of the human epidermal growth factor receptor gene (psiRNA-EGFR) to downregulate the EGFR gene by electrostatic interaction. The antitumor effect of psiRNA-EGFR delivered via Tat-BMPs-PAMAM was assessed both in human glioblastoma U251-MG cells and in nude mouse models. Compared with control groups, Tat-BMPs-PAMAM/psiRNA-EGFR resulted in better suppression of EGFR expression and a more obviously arrested effect on the proliferation and invasion ability of U251 cells in vitro. In addition, the growth rate of tumor in the U251 subcutaneous nude mouse model treated with Tat-BMPs-PAMAM/psiRNA-EGFR was slower than in those treated with phosphate-buffered saline or Lipofectamine 2000/psiRNA-Scr. Also, compared with control groups, the expression of oncoproteins (EGFR, p-AKT, MMP2/9, PCNA, VEGF, Bcl-2, and cyclin D1) was obviously downregulated and the number of apoptotic cells was clearly increased in the Tat-BMPs-PAMAM/psiRNA-EGFR treatment groups. In addition, there was no significant difference between the results in vitro and in vivo for the Tat-BMPs-PAMAM/psiRNA-EGFR treatment groups and those of the Lipofectamine 2000/psiRNA-EGFR treatment groups. These results show that Tat-BMPs-PAMAM, with its targeted delivery and transmembrane ability, may be a novel gene delivery system with potential applications in the targeted gene therapy of brain tumors.
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PMID:Tat-BMPs-PAMAM conjugates enhance therapeutic effect of small interference RNA on U251 glioma cells in vitro and in vivo. 1989 55

Valproic acid (VPA) is an established drug in the long-term therapy of epilepsy. Recently, VPA has demonstrated antitumor activity as a histone deacetylase (HDAC) inhibitor. In this study, the anticancer properties of VPA on neural crest-derived human tumor cell lines G361 melanoma, U87MG glioblastoma and SKNMC Askin tumor cells were investigated. The effect of VPA on cell growth, apoptotic activity and invasive ability were evaluated. Firstly, VPA induced cell growth inhibition and apoptotic activity, as demonstrated by sulforhodamine B protein assay, annexin V assay and by Western blot analysis for Bcl2 and Bax expression levels, in all three cell lines. In addition, VPA led to a decrease of HDAC-1 protein level, as assessed by Western blot analysis. Treatment with VPA caused a decrease in the invasive ability of all three cell lines. Since the invasion process involves a complex system of tightly regulated proteases, matrix metalloproteinases (MMPs) and their tissue-specific inhibitors (TIMPs), the effect of VPA on MMP and TIMP expressions was analysed. Exposure to VPA resulted in a decrease of MMP2 and MMP9 activity and expression level, as assesssed by gelatin zymography and Western blot analysis. In addition, exposure to VPA led to enhanced expression of TIMP1, as assessed by Western blot. Taken together, our results, besides providing further evidence that VPA may represent a promising therapeutic strategy in cancer treatment, may help in the design of new protocols geared at the treatment of neural crest-derived tumors.
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PMID:Epigenetic modifiers as anticancer drugs: effectiveness of valproic acid in neural crest-derived tumor cells. 2033 66

Interleukin-6 (IL-6) is a growth and survival factor in human glioblastoma cells and plays an important role in malignant progression. However, its role in glioblastoma invasion is still unknown. This study shows how IL-6 promotes cell invasion and migration in U251 and T98G glioblastoma cell lines. The underlying mechanism includes both protease-dependent and -independent manners. Stimulation with IL-6 increased MMP9 expression in the two cell lines but had no influence on MMP2 expression. Fascin-1 is a cell skeleton binding protein and plays a key role in cell migration and invasion. Its binding style directly influences cell morphology and tendency to become deformed. After IL-6 exposure, fascin-1 expression increased in an IL-6 dose-dependent manner. Immunofluorescence also revealed that the binding style of fascin-1 had changed after IL-6 exposure, resulting in a more invasive phenotype of the cells. Three most commonly emphasized invasion-associated signaling pathways, including JAK-STAT3, p42/44 MAPK, and PI3K/AKT, were verified to further illustrate its underlying mechanism. Only phosphorylation of STAT3 at ser 727 site paralleled the IL-6 stimulation, and JSI-124, a specific JAK-STAT3 pathway blocker, deterred the invasion and migration promotive effect of IL-6, indicating that the JAK/STAT3 pathway mediates signal transduction. Furthermore, IL-6 also acts in a paracrine fashion to promote vascular endothelial cell migration, thus facilitating tumor angiogenesis and invasion. These results suggest that IL-6 promotes glioblastoma cell invasion and angiogenesis and may be a potential anti-invasion target.
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PMID:IL-6 promotion of glioblastoma cell invasion and angiogenesis in U251 and T98G cell lines. 2036 49

Invasion of glioblastoma cells significantly reduces the effectiveness of current treatments, highlighting the importance of understanding dispersal mechanisms and characteristics of the invasive population. Induction of calcium fluxes into glioblastoma cells by autocrine glutamate is critical for invasion. However, the target(s) by which calcium acts to stimulate the dispersal of glioblastoma cells is not clear. In this study, we tested the hypothesis that the calcium-activated protease calpain 2 is required for glioblastoma cell invasion. Knockdown of calpain 2 expression using shRNA or chemical inhibition of calpain activity reduced glioblastoma cell invasion by 90%. Interestingly, decreased expression of calpain 2 did not influence morphology or migration, suggesting regulation of invasion specific mechanisms. Consistent with this idea, 39% less extracellular MMP2 was measured from knockdown cells identifying one mechanism by which calpain 2 mediates glioblastoma cell invasion. This is the first report demonstrating that calpain 2 is required for glioblastoma cell invasion.
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PMID:Calpain 2 is required for glioblastoma cell invasion: regulation of matrix metalloproteinase 2. 2073 May 61

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