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)

Highly tumorigenic subpopulations of several solid cancers share characteristics with somatic stem cells. We showed recently that cancer stem cells, or tumor-initiating cells, derived from human glioblastoma surgical specimens and xenografts display resistance to radiation due to increased activation of the DNA damage checkpoint. We additionally showed that these same tumor subpopulations promote tumor angiogenesis through increased expression of vascular endothelial growth factor. These studies and subsequent reports from other researchers support critical roles for cancer stem cells in determining tumor response to therapy. Hypoxia and stem cell maintenance pathways may provide therapeutic targets to sensitize cancer stem cells to cytotoxic therapies to improve cancer patient treatments.
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PMID:Cancer stem cells in radiation resistance. 1790 97

Leucocytes accumulate at sites of inflammation and microbial infection in response to locally produced chemotactic factors. N-formylpeptides produced by Gram negative bacteria were among the first chemotactic factors structurally defined which signal through G protein-coupled formylpeptide receptor (FPR) and FPR-like 1 (FPRL1) expressed by phagocytic leukocytes in human and in mouse homogogues mFPR and mFPR2. During the past few years, a number of pathogen- and host-derived agonists/antagonists for FPR, FPRL1 and another FPR variant FPR-like 2 (FPRL2) have been identified. Activation of formylpeptide receptors (FPRs) in phagocytic leukocytes by agonists results in increased cell chemotaxis, phagocytosis, and release of pro-inflammatory mediators. Peptide agonists for FPRs have also been shown to possess immune adjuvant activity when injected in mice. In addition, FPR aberrantly expressed on highly malignant human glioblastoma cells promotes tumor cell migration, proliferation and production of vascular endothelial growth factor in response to agonists released by necrotic tumor cells. Therefore, formylpeptide receptor ligands, by interacting with FPRs, play important roles in host defense and in the rapid progression of human glioblastoma.
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PMID:Biologically active peptides interacting with the G protein-coupled formylpeptide receptor. 1804 24

The vascular endothelial growth factor (VEGF) plays a key role in tumor angiogenesis. However, clinical trials targeting the VEGF pathway are often ineffective, suggesting that other factors/pathways are also important in tumor angiogenesis. We have previously shown that the Notch ligand Delta-like 4 (DLL4) is up-regulated in tumor vasculature. Here, we show that DLL4, when expressed in tumor cells, functions as a negative regulator of tumor angiogenesis by reducing the number of blood vessels in all five types of xenografts, but acts as a positive driver for tumor growth in two of them (human glioblastoma and prostate cancer). The growth of in vivo models was not related to the effects on growth in vitro. DLL4 expressed in the tumor cells activated Notch signaling in host stromal/endothelial cells, increased blood vessel size, and improved vascular function within tumors. The promotion of tumor growth was, to some extent, due to a reduction of tumor hypoxia and apoptosis. DLL4-expressing tumor cells responded to anti-VEGF therapy with bevacizumab. A soluble form of DLL4 (D4ECD-Fc) blocked tumor growth in both bevacizumab-sensitive and bevacizumab-resistant tumors by disrupting vascular function despite increased tumor vessel density. In addition, we show that DLL4 is up-regulated in tumor cells and tumor endothelial cells of human glioblastoma. Our findings provide a rational basis for the development of novel antiangiogenic strategies via blockade of DLL4/Notch signaling and suggest that combined approaches for interrupting both DLL4 and VEGF pathways may improve antiangiogenic therapy.
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PMID:Delta-like 4 Notch ligand regulates tumor angiogenesis, improves tumor vascular function, and promotes tumor growth in vivo. 1805 50

Vascular endothelial growth factor (VEGF) inhibitors are the most promising anti-angiogenic agents used increasingly in the clinic. However, to be efficient, anti-VEGF agents need to be associated with classic chemotherapy. Exploring gene regulation in tumor cells during anti-angiogenesis might help to comprehend the molecular basis of response to treatment. To generate a defined anti-angiogenic condition in vivo, we transfected human glioma cells with short-interfering RNAs against VEGF-A and implanted them on the chick chorio-allantoic membrane. Gene regulation in avascular tumors was studied using human Affymetrixtrade mark GeneChips. Potentially important genes were further studied in glioma patients. Despite strong VEGF inhibition, we observed recurrent formation of small, avascular tumors. CHI3L2, IL1B, PI3/elafin and CHI3L1, which encodes for YKL-40, a putative prognosticator for various diseases, including cancer, were strongly up-regulated in avascular glioma. In glioblastoma patients, these genes showed coregulation and their expression differed significantly from low-grade glioma. Importantly, high levels of CHI3L1 (p = 0.036) and PI3/elafin mRNA (p = 0.0004) were significantly correlated with poor survival. Cox regression analysis further confirmed that PI3 and CHI3L1 levels are survival markers independent from patient age and sex. Elafin-positive tumor cells were only found in glioblastoma, where they were clustered around necrotic areas. PI3/elafin is strongly induced by serum deprivation and hypoxia in U87 glioma cells in vitro. Our results indicate that anti-angiogenesis in experimental glioma drives expression of critical genes which relate to disease aggressiveness in glioblastoma patients. In particular, CHI3L1 and PI3/elafin may be useful as new prognostic markers and new therapeutic targets.
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PMID:Experimental anti-angiogenesis causes upregulation of genes associated with poor survival in glioblastoma. 1908 18

The objective of this study was to evaluate the effects of combination therapy with photodynamic therapy (PDT) and a novel antiangiogenic regimen using monoclonal antibodies against both vascular endothelial growth factor receptors (VEGFR)-1 (MF1) and VEGFR-2 (DC101) on intracranial glioblastoma xenografts in nude mice. Nude mice bearing intracerebral U87 glioblastoma were treated with PDT and the antiangiogenic regimen (MF1 and DC101) either alone or in combination, while those left untreated served as tumor controls. Tumor volume and animal survival time were analyzed to evaluate the outcome of different treatment modalities. In addition, the immunohistochemical expression of VEGF in the brain adjacent to the tumor, von Willebrand factor (vWF), apoptotic, and proliferative markers in the tumor area were examined. PDT or MF1 + DC101 alone significantly reduced the tumor volume and prolonged the survival time of glioma-implanted animals. Combined therapy markedly reduced tumor volume and increased survival time with significantly better outcomes than both monotherapies. Both vWF and VEGF levels significantly increased after PDT while they both significantly decreased after antiangiogenic treatment, compared with no treatment. PDT plus antiangiogenic treatment led to significant decreases in both vWF and VEGF expression, compared with PDT alone. Either PDT or antiangiogenic treatment alone significantly increased tumor cell apoptosis compared with no treatment, while combination therapy resulted in further augmentation of apoptosis. Antiangiogenic treatment with or without PDT significantly decreased tumor cell proliferation, compared with either no treatment or PDT alone. In summary, we demonstrate both significant inhibition of tumor growth and extended survival of mice treated by the combination therapy with PDT and antiangiogenic agents, compared with each single treatment, suggesting that the combination therapy may be a promising strategy to improve clinical outcomes in glioblastoma.
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PMID:Combination therapy with antiangiogenic treatment and photodynamic therapy for the nude mouse bearing U87 glioblastoma. 1817 12

Inhibition of tumor angiogenesis through modulation of vascular endothelial growth factor (VEGF) and its signaling pathway has been clinically validated as a viable therapeutic modality in the treatment of cancer. The use of artificial transcription factors based on Cys2-His2 zinc-finger proteins (ZFPs) targeting the VEGF promoter offers a novel strategy for modulating VEGF levels in tumors. In order to demonstrate the utility of VEGF-targeted ZFPs as therapeutic agents, we generated adenoviruses (Ads) expressing VEGF promoter-targeted transcriptional repressor ZFP, F435-KOX. A replication-incompetent Ad expressing F435-KO X, namely, Ad-DeltaE1-KOX, significantly reduced VEGF expression and functionally led to inhibition of angiogenesis. In vivo, an oncolytic Ad expressing F435-KOX, namely, Ad-DeltaB7-KOX, elicited a pronounced antitumor effect against a human glioblastoma xenograft model, U87MG. Further, consistent with its expected mechanism of action, Ad-DeltaB7-KOX was shown to greatly reduce the level of VEGF and vessel density in tumor tissue and increase terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL)-positive apoptotic cells in tumors. Survival rates were also significantly increased in Ad-DeltaB7-KOX-treated mice. Taken together, the findings from this study identify F435-KOX as a novel and potent ZFP transcription factor that can inhibit VEGF-A-mediated angiogenesis and offer a novel therapeutic modality in the treatment of cancer.
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PMID:Novel cancer antiangiotherapy using the VEGF promoter-targeted artificial zinc-finger protein and oncolytic adenovirus. 1839 29

We conducted a phase II study of the combination of temozolomide and angiogenesis inhibitors for treating adult patients with newly diagnosed glioblastoma. Patients who had stable disease following standard radiation therapy received temozolomide for 5 days in 28-day cycles, in combination with daily thalidomide and celecoxib. Patients were treated until tumor progression or development of unacceptable toxicity. Four-month progression-free survival (PFS) from study enrollment was the primary end point, and overall survival (OS) was the secondary end point. In addition, we sought to correlate response with O(6)-methylguanine-DNA methyltransferase promoter methylation status and serum levels of angiogenic peptides. Fifty patients with glioblastoma were enrolled (18 women, 32 men). Median age was 54 years (range, 29-78) and median KPS score was 90 (range, 70-100). From study enrollment, median PFS was 5.9 months (95% confidence interval [CI]: 4.2-8.0) and 4-month PFS was 63% (95% CI: 46%-75%). Median OS was 12.6 months (95% CI: 8.5-16.4) and 1-year OS was 47%. Of the 47 patients evaluable for best response, none had a complete response, five (11%) had partial response, four (9%) had minor response, 22 (47%) had stable disease, and 16 (34%) had progressive disease. Analysis of serial serum samples obtained from 47 patients for four angiogenic peptides failed to show a significant correlation with response or survival for three of the peptides; higher vascular endothelial growth factor levels showed a trend toward correlation with decreased OS (p=0.07) and PFS (p=0.09). The addition of celecoxib and thalidomide to adjuvant temozolomide was well tolerated but did not meet the primary end point of improvement of 4-month PFS from study enrollment.
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PMID:Phase II study of temozolomide, thalidomide, and celecoxib for newly diagnosed glioblastoma in adults. 1840 92

Galectin (Gal) 1 is a hypoxia-regulated proangiogenic factor that also directly participates in glioblastoma cell migration. To determine how Gal-1 exerts its proangiogenic effects, we investigated Gal-1 signaling in the human Hs683 glioblastoma cell line. Galectin 1 signals through the endoplasmic reticulum transmembrane kinase/ribonuclease inositol-requiring 1alpha, which regulates the expression of oxygen-regulated protein 150. Oxygen-regulated protein 150 controls vascular endothelial growth factor maturation. Galectin 1 also modulates the expression of 7 other hypoxia-related genes (i.e. CTGF, ATF3, PPP1R15A, HSPA5, TRA1, and CYR61) that are implicated in angiogenesis. Decreasing Gal-1 expression in Hs683 orthotopic xenografts in mouse brains by siRNA administration impaired endoplasmic reticulum stress and enhanced the therapeutic benefits of the proautophagic drug temozolomide. These results suggest that decreasing Gal-1 expression (e.g. through brain delivery of nonviral infusions of anti-Gal-1 siRNA in patients) can represent an additional therapeutic strategy for glioblastoma.
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PMID:Knocking down galectin 1 in human hs683 glioblastoma cells impairs both angiogenesis and endoplasmic reticulum stress responses. 1843 Dec 51

Gliomas are the most common and deadly tumors in the central nervous system (CNS). In the course of studying the role of chemoattractant receptors in tumor growth and metastasis, we discovered that highly malignant human glioblastoma and anaplastic astrocytoma specimens were stained positively for the formylpeptide receptor (FPR), which is normally expressed in myeloid cells and accounts for their chemotaxis and activation induced by bacterial peptides. Screening of human glioma cell lines revealed that FPR was expressed selectively in glioma cell lines with a more highly malignant phenotype. FPR expressed in glioblastoma cell lines mediates cell chemotaxis, proliferation and production of an angiogenic factor, vascular endothelial growth factor (VEGF), in response to agonists released by necrotic tumor cells. Furthermore, FPR in glioblastoma cells activates the receptor for epidermal growth factor (EGFR) by increasing the phosphorylation of a selected tyrosine residue in the intracellular tail of EGFR. Thus, FPR hijacked by human glioblastoma cells exploits the function of EGFR to promote rapid tumor progression.
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PMID:Receptor "hijacking" by malignant glioma cells: a tactic for tumor progression. 1843 88

Angiogenesis is a major hallmark of cancer cells, and glioblastomas are among the most angiogenic tumors. The cascade of angiogenesis is probably initiated by hypoxia, leading to the production of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). Both VEGF and bFGF have paracrine effects on endothelial cells, pericytes, or both, causing the formation of hyperpermeable tumor blood vessels. Advanced MRI techniques, such as dynamic contrast-enhanced, dynamic susceptibility, and arterial spin labeling MRI, have provided semiquantitative measurements of tumor vascular permeability and perfusion. A decrease in vascular permeability and perfusion can be detected after antiangiogenesis drug treatment, either with monoclonal antibody such as bevacizumab that sequesters VEGF, or small-molecule VEGF receptor tyrosine kinase inhibitors. Therefore, antiangiogenesis therapies are being increasingly adopted for treating glioblastomas. However, caution must be exercised because neural stem cells are also sensitive to antiangiogenesis drugs and the combined effect of ionizing radiation. This article summarizes 30 years of laboratory and clinical research on glioblastoma angiogenesis and discusses its underlying biology, clinical trial results, vascular neuroimaging, and the potential side effects of antiangiogenesis treatment.
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PMID:Antiangiogenesis treatment for glioblastoma multiforme: challenges and opportunities. 1849 63


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