Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0017636 (glioblastoma)
 18,345 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Regulated gene expression may be required for the clinical development of certain gene therapies. Several approaches have been developed that allow pharmacologic control of transgene expression, including the dimerizer-regulated transcriptional system in which rapamycin or its analogs function as transcriptional inducers. These compounds can also act as direct antitumor agents via inhibition of mammalian target of rapamycin (mTOR). We describe the development of an optimized recombinant adeno-associated virus (AAV) expression cassette that allows dimerizer-regulated gene expression from a single vector in vitro and in vivo. After demonstrating multiple cycles of rapamycin-dependent transgene induction following a single administration of an AAV vector in vivo, application of this regulated AAV gene expression system to the pharmacologic control of antiangiogenic therapy was evaluated in preclinical tumor models. Dimerizer-regulated vectors were constructed encoding a soluble inhibitor of the vascular endothelial growth factor (VEGF) pathway. In two subcutaneous models of glioblastoma, regulated expression of the VEGF inhibitor via recombinant AAV-mediated gene transfer, in combination with rapamycin, was shown to decrease tumor growth rate significantly. The dual properties of rapamycin--as a transcriptional inducer and mTOR inhibitor--are exploited in combination with an AAV-encoded antiangiogenic agent to provide a novel approach for the treatment of malignant diseases.
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PMID:Rapamycin-regulated control of antiangiogenic tumor therapy following rAAV-mediated gene transfer. 1724 54

High-grade gliomas comprise the most malignant type of primary brain tumor and are relatively frequent in adults. Recent studies have indicated that the loss of p16, an inhibitor of CDK4, promotes the acquisition of malignant characteristics in gliomas. A correlation between overexpression of urokinase-type plasminogen activator receptor (uPAR) and glioblastoma invasion has also been established. Moreover, uPAR/integrin binding has been shown to initiate or potentiate integrin signaling through focal adhesion kinase and/or src kinases. Our previous studies demonstrated that downregulation of uPAR expression and restoration of p16 regress glioma growth in nude mice and downregulate alphavbeta3 integrin receptor expression. Here, we show the effect of a bicistronic construct on alphavbeta5 integrin receptor expression, angiogenesis and the biochemical pathway that causes glioma cell death. The U251 glioblastoma and a glioblastoma xenograft cell line transduced with a recombinant replication-defective adenovirus vector containing the cDNA of wild-type p16 and antisense RNA of uPAR significantly inhibited human mammary epithelial cell capillary formation and vascular endothelial growth factor (VEGF) expression. Inactivation of anti-apoptotic molecules such as Akt, PARP, activation of caspases and accumulation of heteroduplex chromosomal DNA in pre-G1 phase of the cell cycle was demonstrated by Western blotting, caspase activity assay and FACS analysis. Nuclear DNA fragmentation upon induction of apoptosis was scored using the TUNEL assay. Significant downregulation of alphavbeta5 integrin receptor expression was also confirmed by FACS analysis, immunoprecipitation and RT-PCR. Taken together, the results demonstrate that the sense p16 and anti-sense uPAR bicistronic construct significantly inhibits angiogenesis, induces apoptosis by deregulation of the PI3K-Akt pathway and downregulates alphavbeta5 integrin receptor expression.
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PMID:Sense p16 and antisense uPAR bicistronic construct inhibits angiogenesis and induces glioma cell death. 1727 68

Genetic studies in mice and humans have shown that the transforming growth factor-beta (TGF-beta) type-I receptor activin receptor-like kinase 1 (ALK1) and its co-receptor endoglin play an important role in vascular development and angiogenesis. Here, we demonstrate that ALK1 is a signalling receptor for bone morphogenetic protein-9 (BMP-9) in endothelial cells (ECs). BMP-9 bound with high affinity to ALK1 and endoglin, and weakly to the type-I receptor ALK2 and to the BMP type-II receptor (BMPR-II) and activin type-II receptor (ActR-II) in transfected COS cells. Binding of BMP-9 to ALK2 was greatly facilitated when BMPR-II or ActR-II were co-expressed. Whereas BMP-9 predominantly bound to ALK1 and BMPR-II in ECs, it bound to ALK2 and BMPR-II in myoblasts. In addition, we observed binding of BMP-9 to ALK1 and endoglin in glioblastoma cells. BMP-9 activated Smad1 and/or Smad5, and induced ID1 protein and endoglin mRNA expression in ECs. Furthermore, BMP-9 was found to inhibit basic fibroblast growth factor (bFGF)-stimulated proliferation and migration of bovine aortic ECs (BAECs) and to block vascular endothelial growth factor (VEGF)-induced angiogenesis. Taken together, these results suggest that BMP-9 is a physiological ALK1 ligand that plays an important role in the regulation of angiogenesis.
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PMID:BMP-9 signals via ALK1 and inhibits bFGF-induced endothelial cell proliferation and VEGF-stimulated angiogenesis. 1731 49

The fluorescence of protoporphyrin IX (PpIX) induced endogenously by 5-aminolevulinic acid (5-ALA) administration has recently been used for the intraoperative visualization of glioma tissues. To increase the sensitivity of photodetection, the emission spectra of 5-ALA-induced PpIX fluorescence was quantitatively measured in tissues taken from six cases of en bloc resected diffusely infiltrating astrocytomas (2 diffuse astrocytomas, 2 anaplastic astrocytomas, and 2 glioblastomas), and the correlation assessed between the fluorescence intensity and histological features. A total of 65 slices were analyzed by ex vivo spectroscopy. The ratio of the peak emission intensity to reflected excitation intensity or fluorescence intensity ratio was less than 0.001 for all 36 non-tumor tissues. The tissues with glioblastoma morphology had a fluorescence intensity ratio in excess of 0.090. The spectroscopic fluorescence intensity was positively correlated with the MIB-1 labeling index as an indicator of proliferation activity, the CD31-microvessel density as a pan-endothelial marker, and the vascular endothelial growth factor expression as an angiogenetic factor. The MIB-1 proliferation index was the most powerful determinant, suggesting that higher cell proliferation may govern preferential PpIX accumulation in glioma cells. This preliminary study suggests that spectroscopic analysis may be useful for optimizing the removal of diffuse gliomas.
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PMID:Quantitative spectroscopic analysis of 5-aminolevulinic acid-induced protoporphyrin IX fluorescence intensity in diffusely infiltrating astrocytomas. 1731 41

Nordy is a chiral compound synthesized based on the structure of a natural lipoxygenase (LO) inhibitor nordihydroguaiaretic acid (NDGA) from plants. The aim of the present study is to investigate the effect of Nordy on malignant human glioma cell responses to chemoattractants and growth promoting signals. We found that Nordy, in a non-cytotoxic concentration range, potently inhibited the chemotaxis and calcium flux of a human glioblastoma cell line U87 induced by a formylpeptide receptor (FPR) agonist, formyl-methionyl-leucyl-phenylalanine (fMLF) and epidermal growth factor (EGF). U87 cells treated by Nordy also showed a significantly impaired proliferation and expression of mRNA for vascular endothelial growth factor (VEGF) induced by fMLF. The chemotactic and proliferation responses of Nordy treated U87 cells to EGF were concomitantly diminished. Further experiments revealed that Nordy did not significantly affect FPR gene expression in U87 cells, but attenuated the activation of a plethora of signaling molecules including ERK1/2, p38, JNK, and Akt when the cells were stimulated by fMLF. EGF-induced EGF receptor phosphorylation was also inhibited in Nordy-treated U87 cells. Moreover, Nordy significantly reduced the tumorigenicity of U87 cells in nude mice. Our results suggest that Nordy is capable of inhibiting glioma cell responses to signals that promote cell motility, growth and production of VEGF. Thus, Nordy may constitute a molecular basis for the development of novel anti-cancer drugs.
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PMID:A novel lipoxygenase inhibitor Nordy attenuates malignant human glioma cell responses to chemotactic and growth stimulating factors. 1737 39

Glioblastomas represent an important cause of cancer-related mortality with poor survival. Despite many advances, the mean survival time has not significantly improved in the last decades. New experimental approaches have shown tumor regression after the grafting of neural stem cells and human mesenchymal stem cells into experimental intracranial gliomas of adult rodents. However, the cell source seems to be an important limitation for autologous transplantation in glioblastoma. In the present study, we evaluated the tumor targeting and antitumor activity of human skin-derived stem cells (hSDSCs) in human brain tumor models. The hSDSCs exhibit tumor targeting characteristics in vivo when injected into the controlateral hemisphere or into the tail vein of mice. When implanted directly into glioblastomas, hSDSCs distributed themselves extensively throughout the tumor mass, reduced tumor vessel density, and decreased angiogenic sprouts. In addition, transplanted hSDSCs differentiate into pericyte cell and release high amounts of human transforming growth factor-beta1 with low expression of vascular endothelial growth factor, which may contribute to the decreased tumor cell invasion and number of tumor vessels. In long-term experiments, the hSDSCs were also able to significantly inhibit tumor growth and to prolong animal survival. Similar behavior was seen when hSDSCs were implanted into two different tumor models, the chicken embryo experimental glioma model and the transgenic Tyrp1-Tag mice. Taken together, these data validate the use of hSDSCs for targeting human brain tumors. They may represent therapeutically effective cells for the treatment of intracranial tumors after autologous transplantation.
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PMID:Effect of human skin-derived stem cells on vessel architecture, tumor growth, and tumor invasion in brain tumor animal models. 1740 12

Nordy is a synthesized chrial compound. To investigate the effects of nordy (25 - 100 micromol x L(-1)) on the function of formylpeptide receptor (FPR) of malignant human glioma cells, human glioblastoma cell line U87 was used to detect its proliferation, migration, calcium mobilization, vascular endothelial growth factor (VEGF) mRNA and protein levels after activation of FPR by its agonist N-formyl-methionyl-leucyl-phenylalanine (fMLF). Cell proliferation, migration ability, VEGF mRNA, VEGF protein and calcium mobilization were evaluated by cell counting, chemotaxis assay, RT-PCR, ELISA and spectrometry. Nordy (50 - 100 micromol x L(-1)) potently inhibited the proliferation, migration and calcium mobilization of U87 cells induced by fMLF (P < 0.05). Moreover, 100 micromol x L(-1) nordy showed a significantly impaired VEGF mRNA expression and protein secretion induced by fMLF (P < 0.05). Nordy could inhibit FPR functioning in glioma cell proliferation, migration and angiogenesis, which might be a possible mechanism of its anti-cancer effects.
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PMID:[Effect of nordy on FPR function of malignant human glioma cell line U87]. 1752 Aug 23

Cell proliferation, migration, and capillary network formation of endothelial cells are the fundamental steps for angiogenesis, which involves the formation of new blood vessels. The purpose of this study is to investigate the effect of a novel aminothiazole SNS-032 on these critical steps for in vitro angiogenesis using a coculture system consisting of human umbilical vein endothelial cells (HUVECs) and human glioblastoma cells (U87MG). SNS-032 is a potent selective inhibitor of cyclin-dependent kinases 2, 7, and 9, and inhibits both transcription and cell cycle. In this study, we examined the proliferation and viability of HUVECs and U87MG cells in the presence of SNS-032 and observed a dose-dependent inhibition of cellular proliferation in both cell lines. SNS-032 inhibited threedimensional capillary network formations of endothelial cells. In a coculture study, SNS-032 completely prevented U87MG cell-mediated capillary formation of HUVECs. This inhibitor also prevented the migration of HUVECs when cultured alone or cocultured with U87MG cells. In addition, SNS-032 significantly prevented the production of vascular endothelial growth factor (VEGF) in both cell lines, whereas SNS-032 was less effective in preventing capillary network formation and migration of endothelial cells when an active recombinant VEGF was added to the medium. In conclusion, SNS-032 prevents in vitro angiogenesis, and this action is attributable to blocking of VEGF.
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PMID:SNS-032 prevents tumor cell-induced angiogenesis by inhibiting vascular endothelial growth factor. 1753 42

The role of vascular endothelial growth factor (VEGF) on cathepsin L expression was investigated in human glioblastoma cells (U87MG). Our results demonstrate the transcriptional upregulation of cathepsin L expression by VEGF. Transient transfection of U87MG cells with VEGF expression vector significantly increased cathepsin L activity. These results were further corroborated by a parallel increase in the mRNA levels and promoter activity of cathepsin L by VEGF. By deletion analysis, we identified a 47 base pair VEGF response element (VRE) in human cathepsin L promoter. Site directed mutagenesis studies demonstrated that both SP-1 and AP-4 motifs present in this region contribute to VEGF responsiveness. These results prove for the first time that over-expression of VEGF in human glioblastoma cells induces cathepsin L expression at the transcriptional level. This mechanism could be involved in the enhanced tumorogenic potential of these cells.
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PMID:Transcriptional upregulation of human cathepsin L by VEGF in glioblastoma cells. 1757 78

Despite aggressive surgery, radiotherapy and chemotherapy, malignant gliomas remain uniformly fatal. To progress, these tumours stimulate the formation of new blood vessels through processes driven primarily by vascular endothelial growth factor (VEGF). However, the resulting vessels are structurally and functionally abnormal, and contribute to a hostile microenvironment (low oxygen tension and high interstitial fluid pressure) that selects for a more malignant phenotype with increased morbidity and mortality. Emerging preclinical and clinical data indicate that anti-VEGF therapies are potentially effective in glioblastoma--the most frequent primary brain tumour--and can transiently normalize tumour vessels. This creates a window of opportunity for optimally combining chemotherapeutics and radiation.
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PMID:Angiogenesis in brain tumours. 1764 88


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