Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0017638 (glioma)
 30,880 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Malignant gliomas are one of the leading causes of cancer deaths worldwide, but chemoprevention strategies for them are few and poorly investigated. Here, we show that cholera toxin, the traditional biotoxin and well known inducer of accumulation of cellular cAMP, is capable of inducing differentiation on malignant gliomas in vitro with rat C6 and primary cultured human glioma cells. Cholera toxin-induced differentiation was characterized by typical morphological changes, increased expression of glial fibrillary acid protein, decreased expression of Ki-67, inhibition of cellular proliferation, and accumulation of cells in the G(1) phase of the cell cycle. Cholera toxin also triggered a significant reduction in the G(1) cell-cycle regulatory proteins cyclin D1 and Cdk2 along with an overexpression of cell-cycle inhibitory proteins p21(Cip1) and p27(Kip1). Abrogation of cAMP-dependent protein kinase A activity by protein kinase A inhibitor or silencing of cAMP-responsive element binding proteins by RNA interference resulted in suppressed differentiation. These findings imply the attractiveness of cholera toxin as a drug candidate for further development of differentiation therapy. Furthermore, activation of the protein kinase A/cAMP-responsive element binding protein pathway may be a key and requisite factor in glioma differentiation.
 ...
PMID:Cholera toxin induces malignant glioma cell differentiation via the PKA/CREB pathway. 1767 96

The purpose of this study was to investigate molecular changes associated with glioma tissues by Raman microspectroscopy in order to develop its use in clinical practice. Spectroscopic markers obtained from C6 glioma tissues were compared to conventional histological and histochemical techniques. Cholesterol and phospholipid contents were highest in corpus callosum and decreased gradually towards the cortex surface as well as in the tumor. Two different necrotic areas have been identified: a fully necrotic zone characterized by the presence of plasma proteins and a peri-necrotic area with a high lipid content. This result was confirmed by Nile Red staining. Additionally, one structure was detected in the periphery of the tumor. Invisible with histopathological hematoxylin and eosin staining, it was revealed by immunohistochemical Ki-67 and MT1-MMP staining used to visualize the proliferative and invasive activities of glioma, respectively. Hierarchical cluster analysis on the only cluster averaged spectra showed a clear distinction between normal, tumoral, necrotic and edematous tissues. Raman microspectroscopy can discriminate between healthy and tumoral brain tissue and yield spectroscopic markers associated with the proliferative and invasive properties of glioblastoma. Development of in vivo Raman spectroscopy could thus accurately define tumor margins, identify tumor remnants, and help in the development of novel therapies for glioblastoma.
 ...
PMID:Discriminating healthy from tumor and necrosis tissue in rat brain tissue samples by Raman spectral imaging. 1776 Nov 39

Growth of solid tumors is highly dependent on angiogenesis. During tumor development, neoplastic cells switch to an angiogenic phenotype, playing a significant role in the expression of the vascular endothelial growth factor (VEGF). Seventy-two brain gliomas were induced in Sprague Dawley rats by prenatal exposure to ethylnitrosourea (ENU). Screening and location of tumors was carried out using magnetic resonance imaging (MRI). Conventional histology and immunocytochemistry for antibodies against glial fibrillary acidic protein (GFAP), S-100, NF, oligodendrocyte Ab-2, Ki-67, and VEGF165 were performed. The proliferation index (PI) was calculated from the Ki-67 labeling index, and the concentration of VEGF165 was quantified by enzyme-linked immunosorbent assay (ELISA). In vivo identification of macro- and microtumor appears to be useful to lead morphological and biochemical studies. Histopathology allows us to identify microtumors as classic oligodendrogliomas (CO; mean PI of 6.01 +/- 2.8%) and macrotumors as anaplastic oligodendrogliomas (AO; mean PI of 14.06 +/- 5%). Classic oligodendrogliomas show scarce VEGF165 expression whereas anaplastic ones display VEGF165 protein level 100-fold increased respect to CO. Astrocytes, neoplastic, and endothelial cells show differential immunostaining patterns from the border to the core of neoplasm. Positive structures for VEGF and their distribution vary according to PI increase. Anaplastic gliomas displaying VEGF-positive intratumor capillaries correspond to the highest PI values. To identify the "angiogenic switch," we propose the glioma stage characterized by VEGF immunopositive neoplastic cells inside the tumor and positive endothelial cells surrounding it.
 ...
PMID:VEGF immunopositivity related to malignancy degree, proliferative activity and angiogenesis in ENU-induced gliomas. 1791 75

Early effects of boron neutron capture therapy (BNCT) on malignant glioma are characterized by reduction of the enhancement area and regression of the peritumoral edema radiologically. The aim of this study was to investigate the early histological changes of tumors and inflammatory cells after BNCT in the rat brain. Rats were treated with BNCT using boronophenylalanine (BPA) 7 days after implantation of C6 glioma cells. The tumors were assessed with magnetic resonance imaging and histopathological examination at 4 days after BNCT. The mean tumor volumes were 39 +/- 2 mm3 in the BNCT group and 134 +/- 18 mm3 in the control group. In the BNCT group, tumor cells showed a less pleomorphic appearance with atypical nuclei and mitotic figures. The Ki-67 labeling index was 6.5% +/- 4.7% in the BNCT and 35% +/- 3.8% in the control group. The reactions of the inflammatory cells were examined with ED-1 as macrophage marker and OX42 as microglia marker. ED-1- and OX-42-positive cells were reduced both in the core and the marginal area of the tumor in the BNCT group. It is suggested that BNCT reduced tumor progression by suppression of proliferation. Inhibition of the activated macrophages may relate to reduced peritumoral edema in the early phase.
 ...
PMID:Early effects of boron neutron capture therapy on rat glioma models. 1809 38

The aim of the study was to investigate the ability of (1)HMRS to reflect proliferative activity of diffuse low-grade gliomas (WHO grade II). Between November 2002 and March 2007, a prospective study was performed on consecutive patients with suspected supratentorial hemispheric diffuse low-grade tumors. All the patients underwent MR examination using uniform procedures, and then surgical resection or biopsy within 2 weeks of the MR examination. Proliferative activity of the tumors was assessed by Ki-67 immunochemistry (Mb-1) on paraffin embedded tumor sections. Spectroscopic data was compared with Ki-67 labeling index and other histologic data such as histological subtype, cellular atypia, cellular density using univariate and multivariate analysis. 82 of 97 consecutive patients had histologically confirmed WHO grade 2 gliomas. Ki-67 proliferation index (PI) was correlated with specific spectral patterns: (1) low PI (<4%) was associated with increased Cho/Cr and absence of both free lipids or lactates; (2) intermediate PI (4-8%) was associated with resonance of lactates; and (3) high PI (>8%) was characterized by a resonance of free lipids. On multivariate analysis, resonance of lactates and resonance of free lipids appeared as independent predictors of intermediate PI (P < 0.001) and high PI (P < 0.001), respectively; moreover, free lipids resonance was correlated with cellular atypia (P < 0.05). This study suggests that (1)HMRS is a reliable tool to evaluate the proliferation activity of WHO grade 2 glioma and to identify potentially more aggressive clinical behavior.
 ...
PMID:Proton magnetic resonance spectroscopy predicts proliferative activity in diffuse low-grade gliomas. 1816 85

High-grade gliomas release excitotoxic concentrations of glutamate which contributes to their malignant phenotype. To improve our understanding of the mechanisms by which glutamate enhances tumor growth and invasion, we examined alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-mediated signaling in glioma cell lines. shRNA was used to stably knockdown GluR1, the most abundant AMPA receptor subunit in glioma, to evaluate its role in tumor signaling, proliferation and tumorigenicity. In a tissue array, there was a statistically significant increase in GluR1 expression in glioblastoma samples compared to anaplastic astrocytoma and low-grade tumors. In vitro, we observed a time and dose-dependent increase in MAPK phosphorylation following exposure to AMPA, which was blocked with AMPA receptor antagonists and the MEK1 inhibitor PD98059. Retroviral delivery of GluR1 shRNA in U251 and U87 glioma cells reduced GluR1 protein expression, inhibited AMPA-mediated increases in MAPK phosphorylation, and decreased glioma proliferation in vitro. U251 and U87 shGluR1 cells implanted into the flanks of nude mice grew slower than controls, which correlated with a decrease in proliferation measured by Ki-67 staining and an increase in apoptosis. These results suggest that AMPA receptors are abundantly expressed in high-grade gliomas and gene silencing of the GluR1 AMPA receptor subunit results in abrogation of AMPA-mediated signaling and tumor growth.
 ...
PMID:Knockdown of GluR1 expression by RNA interference inhibits glioma proliferation. 1831 90

Quantitative analysis of digitized IHC-stained tissue sections is increasingly used in research studies and clinical practice. Accurate quantification of IHC staining, however, is often complicated by conventional tissue counterstains caused by the color convolution of the IHC chromogen and the counterstain. To overcome this issue, we implemented a new counterstain, Acid Blue 129, which provides homogeneous tissue background staining. Furthermore, we combined this counterstaining technique with a simple, robust, fully automated image segmentation algorithm, which takes advantage of the high degree of color separation between the 3-amino-9-ethyl-carbazole (AEC) chromogen and the Acid Blue 129 counterstain. Rigorous validation of the automated technique against manual segmentation data, using Ki-67 IHC sections from rat C6 glioma and beta-amyloid IHC sections from transgenic mice with amyloid precursor protein (APP) mutations, has shown the automated method to produce highly accurate results compared with ground truth estimates based on the manually segmented images. The synergistic combination of the novel tissue counterstaining and image segmentation techniques described in this study will allow for accurate, reproducible, and efficient quantitative IHC studies for a wide range of antibodies and tissues.
 ...
PMID:Synergistic tissue counterstaining and image segmentation techniques for accurate, quantitative immunohistochemistry. 1857 55

Gliomas currently represent a group of uncommon diseases originating from glial elements. According to their biologic features they can be distinguished in low-grade gliomas--not very aggressive and with a poor tendency to progression--and high-grade gliomas--with a greater proliferative drive and aggressiveness. Such definitions outline two distinct disease types, which profoundly differ as for epidemiological, clinical, diagnostic and molecular features. The introduction of biomolecular techniques has provided a deeper knowledge of low-grade gliomas: the use of new molecular markers, such as Ki-67, makes it possible to study peculiar features of the neoplasm, with strong prognostic implications. Nonetheless, in the literature there is still no agreement on their role, nor on their prognostic validity in pediatric age, also because the criteria that are currently used for adult patients haven't still been codified for pediatric age.
 ...
PMID:[The prognostic role of Ki-67 in childhood low-grade glioma]. 1858 59

Malignant glioneuronal tumors (MGNT) are suggested to be a new entity of glioma defined morphologically as any malignant glioma showing immunohistoichemical evidence of neuronal differentiation. We encountered seven cases of MGNT with oligodendroglioma-like component and investigated alternations of chromosome 1p and 19q in these tumors. Seven patients ranged from 33 to 62 years of age, four females and three males. Immunohistochemical study of these tumors was performed using neuronal markers (synaptophysin, neurofilament, beta-tubulin, chromogranin A and NeuN), astrocytic marker (GFAP) and Ki-67. We undertook a molecular cytogenetic study of tumor specimens obtained from seven patients using fluorescence in situ hybridization (FISH) with DNA probes mapping to chromosome 1p36, 1q25, 19p13 and 19q13. Histologically, these tumors resembled anaplastic oligodendroglioma. Immunohistochemically, tumor cells were immunoreactive for synaptophysin (7/7), neurofilament (6/7), beta-tubulin (5/7), chromogranin A (4/7), NeuN (2/7) and GFAP (7/7). The Ki-67 labeling index ranged from 4.5% to 20.7%. FISH analysis demonstrated either 1p or 19q deletion in all seven cases (100%) and both 1p and 19q deletions in five cases (71%). The 1p deletion was detected in six of seven cases (86%) and 19q deletion was also detected in six (86%). 1p and 19q deletions were present in MGNT, especially those with oligodendroglial components. We suggest that the oligodendroglial-like feature was associated with not only 1p or 19q loss but also differentiation along neuronal cell lines as a factor of favorable prognosis in glial tumors. It is inappropriate to make a diagnosis of oligodendroglioma based only on morphological resemblance to oligodendroglia.
 ...
PMID:Chromosome 1p and 19q deletions in malignant glioneuronal tumors with oligodendroglioma-like component. 1878 Dec 79

Papillary glioneuronal tumors (PGNT) are a rare, recently described form of mixed neoplasm composed of glial and neuronal components. PGNT usually occur in children and young adults, and typically demonstrate low-grade pathology, with a low proliferative index of 1-3%. Here we describe a newly diagnosed case of PGNT with a more aggressive phenotype that required irradiation and chemotherapy. The patient was a 19-year-old female who developed progressive headaches and visual seizures. An MRI revealed a heterogeneously enhancing solid mass in the left temporo-occipital region, with significant surrounding edema and mass effect. The mass was resected under stealth guidance without complication. Postoperative MRI scans showed patchy enhancement and residual T2 and FLAIR abnormality. Pathology revealed a highly cellular neoplasm with papillary-like structures, containing cells with glial and neuronal differentiation. Regions of mitoses and focal necrosis were noted, along with a Ki-67 labeling index of 26%. The diagnosis was aggressive PGNT, and treatment consisted of conformal irradiation and concomitant temozolomide over 6 weeks. Postirradiation follow-up MRI scans demonstrated a reduction of residual enhancement and FLAIR abnormality. The patient continues standard-dose adjuvant temozolomide on a monthly basis, with further improvement on subsequent MRI scans and a stable neurologic exam. This patient demonstrates that PGNT may, in rare cases, display an aggressive clinicopathologic phenotype that requires a therapeutic approach more consistent with a high-grade glioma.
 ...
PMID:Aggressive papillary glioneuronal tumor: case report and literature review. 1880 63


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