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)

Aim of this study was to develop and characterize an applicable in vivo model to investigate angiogenesis of human gliomas. An established glioblastoma spheroid model was used to investigate the neovascularization of a standardized avascular solid tumor mass. Spheroids of two human glioma cell lines were labeled with an in vivo fluorescent dye. Single spheroids were implanted into the cortex of athymic rats. After 1, 3, 7, 14, and 21 days, brain sections containing the spheroid were immunostained for endothelial cells or vascular endothelial growth factor (VEGF). The dye-stained glioma spheroid and the endothelial cells were visualized by confocal microscopy. Two distinct mechanisms of tumor vascularization could be observed. (1) "Classical" angiogenesis with new vessels sprouting from existing host vessels into the spheroid was seen. (2) Individual endothelial cells were found to migrate towards and into the center of the spheroid where they coalesced to form new vessels. This process occurred as early as 24 hr after spheroid implantation. Spheroid vascularization was accompanied by an increase of VEGF expression, which peaked 7 days after implantation and returned to normal patterns by 14-21 days. Besides the "classical" angiogenesis by angiogenic blood vessels, the recruitment of individual endothelial cells seems to be an additional mechanism in early glioma vascularization. Our model proves to be a reliable, reproducible system to study in vivo angiogenesis of human gliomas.
 ...
PMID:Vascularization of human glioma spheroids implanted into rat cortex is conferred by two distinct mechanisms. 1072 58

Calpain is a calcium-dependent cysteine protease that is implicated in calcium-dependent cell death, and calpain inhibitors are generally considered as inhibitors of apoptosis. To the contrary, in the present study, we found that calpain inhibitor II (CPI-2) triggers rapid apoptosis in acute lymphoblastic leukemia (ALL) and non-Hodgkin's lymphoma (NHL) cells. All target cell lines were killed by CPI-2, including: ALL-1, a multidrug-resistant BCR-ABL fusion transcript-positive t(9;22) pro-B ALL cell line; RS4;11, a highly radiation-resistant MLL-AF4 fusion transcript-positive t(4;11) pre-pre B ALL cell line; RAMOS, a highly radiation-resistant and p53-deficient Burkitt's lymphoma cell line; DAUDI, a Burkitt's leukemia/lymphoma cell line; NALM-6, a pre-B ALL cell line; and JURKAT and MOLT-3, two T-lineage ALL/NHL cell lines. CPI-2-induced apoptosis in LYN-deficient and BTK-deficient subclones of the DT-40 lymphoma B cell line as effectively as it did in wild-type DT-40 cells. Thus, CPI-2-induced apoptosis is not dependent on the protein tyrosine kinases LYN or BTK. Notably, caspase inhibitor I effectively inhibited CPI-2-induced apoptosis, suggesting that the inhibition of a CPI-2-susceptible protease results in caspase activation, leading to apoptosis in ALL/NHL cells. Unlike the high calpain-expressing ALL/NHL cell lines, myeloid leukemia cell lines HL-60/AML, K562/CML, and U937/AMML, or solid tumor cell lines BT-20/breast cancer, PC-3/prostate cancer, U373/glioblastoma, and HeLa/epitheloid cancer, were not susceptible to the cytotoxicity of CPI-2. Taken together, our results identify calpain as a new molecular target for the treatment of ALL and NHL. CPI-2 and its analogues represent a promising new class of antileukemia/lymphoma agents that deserves further development.
 ...
PMID:Calpain inhibitor II induces caspase-dependent apoptosis in human acute lymphoblastic leukemia and non-Hodgkin's lymphoma cells as well as some solid tumor cells. 1087 99

The transduction efficiencies of adeno-associated viral vectors (AAV, serotype 2) and adenovirus vectors (ADV, serotype 5) were examined in three different models of cancer. First, we used flow cytometry to quantitate AAV-GFP or ADV-GFP transduction in 13 cell lines derived from malignant tissue (6 gliomas, 6 mammary cancers, and 1 leukemia). These experiments showed variable transduction efficiency (0%-81%) between the cell lines, with ADV being more effective compared to AAV in 9 of 13 cell lines. Second, spheroids prepared from human glioblastomas were infected with ADV or AAV expressing GFP or lacZ cassettes, and after 2 weeks, uniform reporter gene expression was observed on the spheroid. Whereas AAV produced consistent transduction throughout the spheroids, ADV infection was mainly limited to the outer cell layers of the spheroids, suggesting that AAV were more efficient at penetrating solid tumor tissue. Third, human biopsies from glioblastoma multiforme patients were xenografted into nude rats and grown for 4 weeks followed by viral vector injection. Combined use of high-resolution magnetic resonance imaging (MRI) and histologic analysis allowed the identification of transduced cells and their spatial distribution within the tumors. AAV-mediated transgene expression was observed in cell clusters through the entire tumor, while ADV-mediated transduction was restricted to cells at the tumor periphery. Thus, while AAV and ADV vectors may infect tumor-derived cell lines to a similar degree, AAV penetrated glioblastoma spheroids and xenografts more efficiently compared to ADV vectors. These results suggest that AAV may be suitable for therapeutic gene delivery to malignant tumors.
 ...
PMID:Adeno-associated viral vectors penetrate human solid tumor tissue in vivo more effectively than adenoviral vectors. 1206 44

Epidermal growth factor receptor (EGFR) gene amplification occurs in glioblastomas as so-called double minutes. Because double minutes are extrachromosomal fragments, selection pressures must operate to maintain high EGFR copy number over multiple cell divisions. In analyses of glioblastoma lysates, EGFR amplification has been observed almost exclusively in glioblastomas harboring wild-type TP53 genes, which raises the alternative hypotheses that TP53 mutation either prevents amplification or selects against maintenance of EGFR-amplified cells. To address these possibilities at the cellular level, we studied 14 glioblastomas for TP53 mutation and EGFR gene amplification status, using fluorescence in situ hybridization (FISH) for the latter. Remarkably, four of the six cases with TP53 mutation had isolated EGFR-amplified cells in different regions, demonstrating that EGFR amplification occurs frequently at the cellular level in TP53-mutant glioblastomas. Thus, TP53 mutation does not prevent EGFR amplification but does not facilitate selection of EGFR-amplified cells. Of the eight cases without TP53 mutation, five had widespread EGFR amplification. In four of these five cases, multiple regions of the tumor were available for examination; FISH demonstrated a gradation of EGFR amplification, with highly amplified cells, primarily at the invading edges rather than the relatively solid tumor centers, suggesting that EGFR overexpression, when selected for in vivo, may be related to tumor invasion.
 ...
PMID:Selection pressures of TP53 mutation and microenvironmental location influence epidermal growth factor receptor gene amplification in human glioblastomas. 1254 96

To develop novel therapeutic agents for the treatment of brain tumors, we have been investigating the expression of unique tumor-associated receptors or antigens on the tumor cell surface. About six years ago, we discovered that human solid tumor cell lines, including human malignant glioma, express high- to intermediate-affinity receptors (R) for a Th2 cell-derived cytokine, interleukin-13 (IL-13). Analysis of the subunit composition of IL-13R in primary explants of malignant glioma cells has demonstrated that IL-13R is composed of three different chains (IL-13R alpha 1, IL-13R alpha 2 and IL-4R alpha, also known as IL-13R alpha', alpha and IL-4R beta, respectively) and that IL-13R alpha 2 chain is overexpressed on these cells. Normal brain tissues express IL-13R alpha 1 and IL-4R alpha chains, but show only marginal expression of IL-13R alpha 2 chain. Thus IL-13R alpha 2 chain appears to be overexpressed on glioma cells and may serve as a novel tumor biomarker or a target for receptor-directed therapeutic agents for brain tumors. To target IL-13 receptors, we have produced a recombinant fusion protein composed of IL-13 and a mutated form of Pseudomonas exotoxin (PE). This cytotoxin, termed IL-13PE38QQR or IL-13 cytotoxin, is highly and specifically cytotoxic to a spectrum of human glioma cell lines. In preclinical models of human glioblastoma tumors growing subcutaneously in immunodeficient mice, IL-13 cytotoxin has been found to have remarkable antitumor activity. The data that emerged from these studies reveal that localized or systemic administration of IL-13 cytotoxin can produce nontoxic drug levels and that IL-13 cytotoxin is potently effective against established glioblastoma tumors. On the basis of these and other preclinical studies, we have begun a phase I clinical trial using IL-13PE38QQR for therapy of recurrent malignant glioma.
 ...
PMID:Preclinical studies with IL-13PE38QQR for therapy of malignant glioma. 1287 31

Considerable efforts have been invested to improve local control of the glioma disease although its infiltrative nature leading to whole brain involvement is a fundamental characteristic and antagonistic to this endeavour. The typically local recurrence of glioblastoma in about 80% of the cases has prompted intracavitary treatments of which presently only a biodegradable wafer containing carmustine has shown statistically significant benefit regarding survival in three phase III trials. Based on that proof of principle, many new developments are attempting to improve on this concept, introducing different agents with otherwise high systemic toxicity and poor penetration. New pharmacological formulations offer longer sustained release, better adaptation to the geometry of the resection cavity, and allow repeated administration. Should local recurrence become effectively controlled, significant progress can be made to increase survival with very limited local and virtually no systemic side effects. Since all agents so far show only limited activity against solid tumor, complete resection seems to be the prerequisite for effective local therapies.
 ...
PMID:Intracavitary chemotherapy for glioblastoma: present status and future directions. 1453 63

Human malignant glioma cell lines, primary cell cultures, and tumor specimens derived from surgical samples have been shown to overexpress high-affinity receptors (R) for interleukin-4 (IL-4) in vitro and in situ. The significance of IL-4R expression on malignant glioma cells is still unclear. However, IL-4 has been reported to mediate functional effects in several solid tumor cell lines. These activities include inhibition of cell proliferation, regulation of adhesion molecules, and induction of signal transduction through the JAK/STAT pathway. To target IL-4Rs on tumor cells, we have produced a chimeric recombinant fusion protein consisting of a binding ligand, circularly permuted IL-4 and a mutated form of Pseudomonas exotoxin. This molecule is termed IL4(38-37)-PE38KDEL, cpIL4-PE, or IL-4 cytotoxin. Recombinant cpIL4-PE is highly and specifically cytotoxic to glioma cell lines in vitro, while it is not cytotoxic or less cytotoxic to hematopoietic and normal brain cells. In a nude mouse model, cpIL4-PE showed significant antitumor activity and partial or complete regression of small or large established human glioblastoma tumors. Encouraging preclinical efficacy, safety, and tolerability studies lead to testing of this agent in patients with recurrent glioblastoma. Based on these pilot studies, an extended Phase I/II clinical trial is currently ongoing to determine safety, tolerability, and efficacy of cpIL4-PE when injected stereotactically directly into the recurrent glioma by convection enhanced delivery. Preliminary clinical results suggest that cpIL4-PE can cause pronounced necrosis of recurrent glioma tumors without systemic toxicity. The central nervous system toxicities observed were attributed to the volume of infusion and/or nonspecific toxicity. Ongoing clinical trials will reveal antitumor activities of IL-4 cytotoxin in recurrent malignant glioma.
 ...
PMID:Interleukin-4-Pseudomonas exotoxin chimeric fusion protein for malignant glioma therapy. 1464 82

Radiosensitizers represent an enticing concept in tumor therapy. As ionizing radiation affects both neoplastic and normal tissues, its effects are generally non-specific. The aim of applying a radiosensitizing agent is to achieve a maximum effect on tumor tissue, while minimizing the damage to normal tissues. A variety of parameters such as the oxygen supply and the state in the cell cycle, need to be taken into account when evaluating a potential radiosensitizer. Most of the previously known radiosensitizers are neither selective nor tumor specific. In this article, we review the properties and radiosensitizing potential of Photofrin II. Photofrin II is well-known as a photosensitizing agent in photodynamic therapy. In recent years, a radiosensitizing potential of the substance has been demonstrated, specifically increasing the sensitivity of solid tumor tissues, especially of radio-resistant, hypoxic tumor cells, to radiation. This radiosensitizing effect has been demonstrated both by in vitro studies and by animal experiments. Several studies with tissue cultures have demonstrated a radiosensitizing effect of Photofrin II in glioblastoma (U-373MG) and bladder cancer cell lines (RT-4). No effect was noted in colon carcinoma cell lines (HT-29). Unpublished data of additional cell lines will be mentioned in the review. Animal experiments with Lewis sarcoma and with bladder cancer have moreover demonstrated an in vivo effect of Photofrin II as a radiosensitizer. The mechanism of this radiosensitizing effect is not completely understood. In vitro data, however, support the hypothesis that the radiosensitizing action involves OH-radicals in addition to a potential impairment of repair mechanisms after sublethal damage of ionizing radiation. Moreover, early results of a phase I trial are available and document the potential feasibility of the application of Phototofrin II as a radiosensitizing agent in clinical practice.
 ...
PMID:The Application of Photofrin II as a sensitizing agent for ionizing radiation--a new approach in tumor therapy? 1589 32

MAGE derived HLA ligands have repeatedly been shown to elicit T-cell responses against tumor cells. In renal cell carcinoma (RCC), however, only few T-cell epitopes from cancer testis antigens have been described. To identify potential candidates, we applied a combined approach of microarray/qPCR expression analysis and sequencing of HLA ligands from RCC by mass spectrometry. We analyzed the expression of 21 MAGE genes in ten RCC samples and two glioblastoma samples and could identify the first MHC class I ligand NIGDEALIGRW from MAGED4 presented by HLA-A*25 on RCC solid tumor tissue. MAGED4 was expressed in 30% of RCC and both glioblastoma samples. Among the other MAGE family members only MAGEB2 and -C1 and the broadly expressed MAGED1, -D2, -F1 and -H1 were expressed in RCC. Ligands from MAGED4 could thus be interesting tumor-associated antigens in a subset of RCC, even though the identified ligand is presented by a rather rare allele.
 ...
PMID:MAGED4-expression in renal cell carcinoma and identification of an HLA-A*25-restricted MHC class I ligand from solid tumor tissue. 1608 91

A 67-year-old male presented with a clear cell ependymoma with symptoms of ataxic gait and dizziness. Magnetic resonance imaging showed a ring enhanced and circumscribed mass lesion with some cysts in the left cerebellar hemisphere, and the vertebral artery angiogram showed the vascurality of the tumor fed by both the left posterior inferior cerebellar artery and the left superior cerebellar artery mainly. They demonstrated suspicious finding of metastatic tumor, glioblastoma, or cystic meningioma. Surgery via the left suboccipital approach revealed a whitish and solid tumor, which was demarcated from the cerebellar parenchyma and had no continuity with the 4th ventricle. Total resection of the tumor was successfully performed. The hematoxilyn-eosin staining of the surgical specimen was similar to hemangioblastoma or oligodendroglioma, however, immunohistochemical findings for glial fibrillary acidic protein, vimentin, epithelial membrane antigen, and factor VIII were compatible with clear cell ependymoma. The patient's postoperative course was uneventful, and his symptoms improved. Clear cell ependymoma is known as a variant of ependymoma, which is usually located at the foramen of Monro. We think that the immunohistochemical study is highly helpful for the diagnosis of the cerebellar tumor with atypical presentation such as our case.
 ...
PMID:[Immunohistochemical study is helpful for the diagnosis of cerebellar clear cell ependymoma with atypical radiological findings--case report]. 1627 26


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>