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)

Two novel porphyrin-bisacridine conjugates (1 and 2) were designed as bifunctional antitumour agents to combine the DNA-binding character of the acridines and the photosensitizing capacity of porphyrin, and have been subjected to biophysical and biological evaluation. The interactions of the conjugates with calf thymus DNA were evaluated using viscometric, spectrophotometric and stopped-flow sodium dodecyl sulphate (SDS) sequestration methods. Both conjugates acted as bis-intercalators via the two acridine chromophores and displayed a longer residence time on DNA relative to the parent acridine ligand. Their biological activity in vitro was studied against the C6 rat glioma, MCF-7, GBM and A431 cell lines. Both conjugates were cytotoxic to all four cell lines. The ID50 (C6 glioma) was essentially the same as that of the parent acridine for one conjugate, but was increased 20-fold for the other, while both conjugates were approximately 10-fold more cytotoxic than the parent porphyrin component. The tissue distribution of the two conjugates was assessed in nude mice xenografted with a human small cell lung carcinoma (POVD). There were large differences in the tissue distribution of the two conjugates, with conjugate 2 localizing 8-fold more in the tumour than conjugate 1.
 ...
PMID:Biophysical and biological evaluation of porphyrin-bisacridine conjugates. 866 8

Three series of new boron-containing spermidine/spermine (SPD/SPM) analogues have been synthesized: N1- and N5-(4-carboranylbutyl) SPD/SPM derivatives (SPD-1, SPD-5, SPM-1, SPM-5); N1,N10-diethyl-N5-(4-carboranylbutyl)spermidine (DESPD-5), N1,N14-diethyl-N5-(4-carboranylbutyl)spermine (DESPM-5); and N5,N10-bis(4-carboranylbutyl)spermine (SPM-5,10). In vitro studies using rat F98 glioma cells have shown that these polyamines retain the ability to displace ethidium bromide from calf thymus DNA and are rapidly taken up by F98 glioma cells. However, their cytotoxicities, especially those with terminal N-substituted (SPD-1, SPM-1) boron compounds, are greater than those of SPD/SPM. Nevertheless, the groundwork has been created for a new class of boron-containing compounds that maybe useful for boron neutron capture therapy of tumors.
 ...
PMID:Boron-containing polyamines as DNA targeting agents for neutron capture therapy of brain tumors: synthesis and biological evaluation. 939 69

Binding and toxicity of boronated phenanthridinium analogues were studied in vitro using cultured human malignant glioma cells. The compounds, 5-ortho- (5-o-CP), 5-para- (5-p-CP), 5-nido- (5-n-CP) and 6-nido-carboranyl phenanthridinium (6-n-CP) showed varying toxic effects. The cells were exposed to the compounds for 2 or 24 h. The span between non-toxic and toxic concentrations seemed to be very narrow. 5-p-CP was the most toxic compound, causing total cell death at a concentration of 5 micrograms/ml cell culture medium. None of the compounds showed toxic effects at a concentration of 1 microgram/ml. Viable cells incubated with the compounds at this concentration showed a > 100-fold accumulation of boron. Only approximately 1/4 of this accumulation was found in cells permeabilized and inactivated with acetone. Fluorescent images of acetone-treated cells showed clear uptake of the compounds in the cell nucleus, as for ethidium bromide, while for viable cells binding to structures other than DNA was also observed. These results were confirmed by subcellular boron determination. All tested compounds intercalate into DNA, as was demonstrated in cell-free systems with calf thymus DNA. The hypothesis is that the compounds are trapped in the cellular membranes of viable cells because of their lipophilicity, before reaching nuclear DNA.
 ...
PMID:Cytotoxicity and subcellular localization of boronated phenanthridinium analogues. 944 6

Thymosin fraction 5 (TF5) is a partially purified preparation of the bovine thymus possessing immunopotentiating properties. TF5 also stimulates the hypothalamic-pituitary-adrenal axis in vivo and anterior pituitary hormone release in vitro. Interleukin-6 (IL-6) is an inflammatory, pyrogenic cytokine that also stimulates hypothalamic and anterior pituitary hormone release. We hypothesized that TF5 may activate the neuroendocrine system in part via the stimulation of central cytokine production. Therefore, we determined the effects of TF5 on IL-6 release from rat C6 glioma cells in vitro. Glioma cells (25-100 x 10(3)) were exposed to vehicle (RPMI-1640) or TF5 (10-1,000 micrograms/ml) in 96-well plates (200 microliters incubation volume) for 4-24 h to determine optimal cell number and incubation period conditions. TF5 (1,000 micrograms/ml) stimulated IL-6 release from 100 x 10(3) C6 cells/well by 9-fold following a 24-hour incubation (p < 0.01). Reducing the number of cultured C6 cells to either 50 or 25 x 10(3) cells/well resulted in diminished IL-6 responses to TF5. TF5 stimulated C6 cell IL-6 release in a time-dependent manner (4-24 h) at all concentrations tested. A 24-hour incubation period provided the largest TF5-stimulated increases in IL-6 release compared with shorter time intervals (i.e., 4-8 h). Pretreatment of C6 glioma cells with 1 microM phorbol myristate acetate (PMA) for 24 h completely blocked the subsequent stimulation of IL-6 release by PMA (20-250 nM) and partially blocked by 50% the TF5 stimulation of this cytokine. Peptides previously purified from TF5 had no effect on IL-6 release at 50-1,000 nM [i.e., thymosin alpha 1 (T alpha 1), thymosin beta 4 (T beta 4), MB35, MB40]. Therefore, TF5 was further fractionated into 7 pools by preparative reverse phase high performance liquid chromatography (HPLC). HPLC pools P1 (fractions 1-8) and P2 (fractions 9-12) significantly increased C6 cell IL-6 release (p < 0.01) to the same extent as 250 micrograms/ml TF5. Other HPLC pooled fractions (P3-P7) had no effect on IL-6 release from C6 glioma cells. P1 and P2 stimulated a 50- and 10-fold increase in IL-6 release, respectively, at a protein concentration of 1.0 microgram/ml. Therefore, P1 was more potent and displayed a greater efficacy for the stimulation of IL-6 release compared to P2. Analysis of individual fractions of P1 and P2 revealed that 1 microgram/ml of fraction 6 was as efficacious as 250 micrograms/ml TF5 for the stimulation of IL-6 release. These data indicate that one or more peptide components of TF5 enhance glial cell production of IL-6. In addition, the thymosin-stimulated production of extracellular IL-6 is mediated partially by one or more isoforms of protein kinase C. We hypothesize that a peptide product of the thymus transported across the CNS blood-brain barrier may stimulate the glial cell production of IL-6 and affect neuronal, neuroendocrine and/or inflammatory processes.
 ...
PMID:A novel thymosin peptide stimulates interleukin-6 release from rat C6 glioma cells in vitro. 950 Jan 50

Cytokines such as interleukin-1 (IL-1) and IL-6 stimulate the hypothalamic-pituitary-adrenal (HPA) axis. In addition, these proteins affect pituitary cell proliferation in vitro. Thymosin fraction 5 (TF5) is a partially purified preparation of the bovine thymus that enhances immune system functioning. Because TF5 similarly stimulates the HPA axis, we examined the effects of this preparation on neuroendocrine tumor cell proliferation. Cells of the PRL-secreting rat anterior pituitary adenoma, MMQ (5-50 x 10(3) cells/well), were exposed to vehicle (RPMI-1640 containing 2.5% FCS, 7.5% horse serum, and antibiotics) or TF5 (100-500 microg/ml) for up to 96 h and the proliferation of MMQ cells monitored using the MTT assay (3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide). TF5-mediated inhibition of cell proliferation was dependent on both TF5 concentration and the initial MMQ cell number. Minimal reductions in optical densities resulted from exposure to 100 microg/ml TF5, whereas the highest concentration of this preparation (i.e. 500 microg/ml) completely blocked MMQ cell division. The concentration-dependent effects of TF5 were particularly striking at initial plating densities of 25 and 50 x 10(3) MMQ cells/well; in contrast, all concentrations of TF5 completely inhibited MMQ cell growth at 5 and 10 x 10(3) cells/well. The antiproliferative actions of TF5 on MMQ cells were demonstrable within 24 h and remained for up to 96 h as determined by the MTT assay and actual cell counts. Because the highest densities of MMQ cells were partially refractive to the antiproliferative effects of TF5, we examined the effects of PRL (1-1000 nM) and MMQ cell conditioned medium (50%) on TF5 inhibition of MMQ adenoma proliferation. The TF5 concentration-dependent inhibition of MMQ cell growth was largely reversed by the 50% conditioned medium, whereas PRL slightly potentiated the antiproliferative actions of TF5. The proliferation of the rat C6 glioma cell line (10-30 x 10(3) cells/well) demonstrated greater sensitivity to TF5: concentrations as low as 10 microg/ml TF5 inhibited C6 cell proliferation (P < 0.01), and near-maximal inhibition was noted at 200 microg/ml TF5. Significant reductions in MMQ and C6 cell viabilities accompanied decreases in cell number and morphological analysis indicated these cells were dying by apoptosis. The peptides thymosin alpha1 (T alpha1), thymosin beta4 (T beta4), MB35, and MB40 had no effect on either MMQ or C6 cell proliferation, indicating that these TF5 components are not the principle active peptides. Therefore, TF5 was further separated into 60 fractions by preparative reverse phase HPLC. HPLC fractions 17, 25, 26, and 27 significantly suppressed MMQ cell proliferation (P < 0.01) to the same extent as TF5; other HPLC fractions had no effect. These data demonstrate a new biological property of TF5: the inhibition of cell proliferation and the induction of apoptosis in neuroendocrine tumor cells. The proliferation effects were time and concentration dependent and could be partially reversed by an activity present in the MMQ cell conditioned medium. Thus, TF5 and cytokines have opposite effects on adenoma cells because IL-2 and IL-6 stimulate GH3 cell proliferation. We propose that circulating thymic peptides may act to prevent pituitary adenoma and glioma tumor formation, an action opposed by autocrine growth factors secreted by these tumors.
 ...
PMID:Thymosin fraction 5 inhibits the proliferation of the rat neuroendocrine MMQ pituitary adenoma and C6 glioma cell lines in vitro. 952 5

During postnatal development, the formation of new blood vessels is possible only through angiogenesis. The initial growth of solid neoplasms, including childhood brain tumors, during the genetically determined stages of carcinogenesis, even at clinically undetectable sizes (a few mm3), depends upon the continuous formation of new blood capillaries [i.e. neovascularization (NV)/neoplasm-related angiogenesis (NRA)]. The generation of a malignant, invasive cellular immunophenotype (CIP) and distant metastases are also NRA-dependent processes. Endothelial cells undergo rapid proliferation during brain tumor related angiogenesis. Human endoglin (CD105/EDG), is a homodimeric cell surface component of the transforming growth factor-beta (TGF-beta) type I receptor complex and is also a proliferation-associated antigen (PAA) expressed at high density on endothelial cells. Formalin fixed, paraffin-wax embedded (3-5 microns thick), as well as frozen tissue sections (6 microns thick) of 62 childhood brain tumors [34 medulloblastomas (MEDs) and 28 astrocytomas (ASTRs)], were employed for the assessment of EDG expression. Both an indirect, four-step, alkaline phosphatase (AP) conjugated, biotin-streptavidin based (or a diamino-benzidine [DAB]) conjugated immunoperoxidase antigen detection technique were employed, utilizing the SN6h anti-EDG monoclonal antibody (DAKO Corp.). Another antigen detection method, based on the Histogold (Zymed) reaction was also employed using the same antibody on formalin fixed, paraffin-wax embedded tissues. Strong expression (A; +3 to +4) of EDG on endothelial cells and demonstrated in all 62 childhood brain tumor cases. The most striking feature of the newly formed tumor-related capillaries was the presence of a markedly enlarged perivascular space. Blood vessels in several normal human tissues (cortex, cerebellum, thymus, tonsil, spleen, lymph node, skin) used as control tissues contained significantly lower levels of EDG (B and mostly C; +/- to +), in accordance with the extremely slow turnover rate of normal endothelial cells. A close apposition between the capillaries and the adjacent parenchyma was also observed. Brain tumors, especially glioblastoma, are among the most vascularized human neoplasms, and thus are candidates for antiangiogenic therapy. VEGF/PF-R1 (flt-1) and VEGF/PF-R2 (flk-1) are formed de novo in a glioma progression-dependent manner. Further studies should substantiate the importance of EDG in the earliest possible detection, diagnosis and NRA inhibition-based treatment of mammalian solid neoplasms, especially childhood brain tumors.
 ...
PMID:Upregulation of endoglin (CD105) expression during childhood brain tumor-related angiogenesis. Anti-angiogenic therapy. 967 60

N-Acetylglucosamine-6-O-sulfotransferase catalyzes the transfer of sulfate from 3'-phosphoadenosine 5'-phosphosulfate to position 6 of a non-reducing N-acetylglucosamine (GlcNAc) residue. We have cloned human GlcNAc-6-O-sulfotransferase cDNA, based on the sequence homology to cloned cDNA of mouse GlcNAc-6-O-sulfotransferase. The predicted protein sequence of the human enzyme was highly homologous to that of the mouse enzyme; in the 363 amino acid stretch of the catalytic region, the two proteins were nearly identical except for conservative changes in 3 amino acid residues. The expressed enzyme transferred sulfate to GlcNAcbeta1-3Galbeta1-4GlcNAcbeta1-3Galbeta1-4Gl cNAc. Co-transfection of the enzyme cDNA and fucosyltransferase VII cDNA into COS-7 cells resulted in cell surface expression of 6-sulfo sialyl Lewis X. Fluorescence in situ hybridization analysis revealed that the GlcNAc-6-O-sulfotransferase gene is located on human chromosome 7q31. mRNA of the human enzyme was strongly expressed in the bone marrow, peripheral blood leukocytes, spleen, brain, spinal cord, ovary, and placenta, and moderate levels of expression were observed in many organs including lymph nodes and thymus. In situ hybridization with the mouse system showed that the transcript was localized in specific regions of the brain, i.e. pyramidal cells in the CA3 subregion of the hippocampus, cerebellar nucleus and Purkinje cells. Among human tumor cells, strong expression of the mRNA was found in MOLT-4 and Jarkat lymphoblastic leukemia cells, Raji lymphoma cells, K-562 chronic myelogeneous leukemia cells, U251 glioma cells, and G361 melanoma cells. Carbohydrate structures synthesized by the sulfotransferase may be involved in various aspects of the differentiation and behavior of blood cells, their progenitor cells, and neurons in the central nervous system.
 ...
PMID:Human N-acetylglucosamine-6-O-sulfotransferase involved in the biosynthesis of 6-sulfo sialyl Lewis X: molecular cloning, chromosomal mapping, and expression in various organs and tumor cells. 972 82

New boron-containing spermidine/spermine (SPD/SPM) analogues have been synthesized: N5-[4-(2-aminoethyl-o-carboranyl)butyl] and N5-{4-[(2,3-dihydroxypropyl)-o-carboranyl]butyl} SPD/SPM derivatives (ASPD-5, ASPM-5, DHSPD-5, and DHSPM-5) as well as N5-{[4-(dihydroxyboryl)phenyl]methyl}spermidine (BBSPD-5). These boronated polyamines retain their ability to displace ethidium bromide from calf thymus DNA and are rapidly taken up in vitro by F98 rat glioma cells. The in vitro toxicities of ASPD-5, ASPM-5, DHSPD-5, and DHSPM-5 are lower than those previously reported for N5-[4-(o-carboranyl)butyl] SPD/SPM derivatives (SPD-5 and SPM-5) but similar to those of native SPD and SPM. Very low toxicity was also observed for BBSPD-5. In vivo studies of ASPD-5 and BBSPD-5 were performed in mice bearing intracerebral implants of the GL261 glioma and subcutaneous implants of the B16 melanoma. The biodistribution data found in both tumor models suggest that the polyamines synthesized to date do not appear to be suitable boron agents for BNCT.
 ...
PMID:Synthesis and biological evaluation of boron-containing polyamines as potential agents for neutron capture therapy of brain tumors. 1019 71

p53 deficient mice have been found to be highly prone to develop tumors spontaneously. In particular, the thymic lymphoma was observed predominantly, which is not the case for p53-related tumorigenesis in human. To elucidate this differences, I tried to rescue the p53 deficient mice from lymphoma originated in thymus by allowing the p53 expression in their lymphocytes by using transgenic technique. They survived longer than the p53 deficient littermates. In addition, they developed various types of tumors including glioma, medulloblastoma and breast cancer, which have not been observed in p53 deficient mice.
 ...
PMID:[Tissue specific rescue of lymphomas arose various types of tumors with p53-deficiency]. 1033 29

Apoptosis is a physiological process wherein the cell initiates a sequence of events culminating in the fragmentation of its DNA, nuclear collapse, and finally disintegration of the cell into small, membrane-bound apoptotic bodies. Expression of Fas (APO-1, CD95) Receptor (FasR) and programmed or active cell (PCD) death was studied in childhood astrocytomas (ASTRs) with varying stages of malignancy, including pilocytic ASTR, low grade ASTR, anaplastic ASTR, and glioblastoma multiforme (GBM). The great majority of childhood glial tumors, particularly ASTRs express FasR whereas normal cells in the central nervous system (CNS) do not. FasR represents a transmembrane glycoprotein which belongs to the nerve growth factor/tumor necrosis factor (NGF/TNF) receptor superfamily. Apoptosis within ASTRs is triggered by the binding of FasR to its natural ligand (FasL) or by cross-linking with antibodies developed against FasR. Presence of FasL was also detected in childhood glial tumors. The expression of both FasR and FasL was also observed within the same ASTRs. Therefore, spontaneous, IP regulatory, intratumoral apoptotic cell death (autocrine suicide) is possible in childhood glial tumors. During a systematic, immunocytochemical screening of 42 childhood ASTRs tissues divided according to WHO classification: 6 WHO grade I or pilocytic ASTRs; 14 WHO grade II or low grade ASTRs; 16 WHO grade III or anaplastic ASTRs and 6 WHO grade IV or glioblastoma multiforme (GBM), we detected strong expression (intensity of staining: "A"--the highest possible; number of stained cells: +2 to +4, between 20% to 90%) of FasR, employing 4 microns thick, formalin fixed, paraffin-wax embedded tissue slides. FasR was present on 70% to 90% of tumor cells in pilocytic ASTRs, in 50% to 60% of the tumor cells in low grade ASTRs, in between 30% and 40% of the tumor cells in anaplastic ASTRs, and in between 20% to 35% of GBM cells. The panel of normal tissues employed as positive and negative tissue controls demonstrated presence of FasR in the prenatal thymus, mature tonsils and colonic epithelium. The use of a sensitive, indirect, six step immunoperoxidase or alkaline phosphatase conjugated streptavidin-biotin antigen detection technique provided excellent immunocytochemical results. A broad spectrum of neoplastic cells have been identified to express FasR: 1) carcinomas of epithelial origin, such as breast (ductal invasive, lobular invasive, mucinous), renal cell, gastric, colorectal, endometrial, prostate, pancreas, hepatocellular and large cell and squamous cell lung carcinomas: 2) non-epithelial neoplasms such as B cell mediastinal B cell and nodal non-Hodgkin's lymphomas large granular lymphocytic leukemia of T or NK cell origin malignant fibrous histiocytoma, malignant mesothelioma, leiomyosarcoma, epitheloid sarcoma and alveolar soft part sarcoma, as well as melanomas. Flow cytometry studies have also detected FasR expression on cells of adult T cell, and hairy cell leukemias, as well as in chronic B cell lymphocytic leukemia (BCLL). The coexpression of both FasR and FasL on several malignant cell types may represent an effective mechanism of tumor escape from the cellular immunological response of the host. It has been well established that brain tumors and melanomas produce their autocrine FasL, and even become capable of switching the signal transduction associated with FasL-FasR coupling from the PCD pathway to a tumor growth, proliferative pathway. It seems that the therapeutical use of FasR-FasL (main apoptotic pathway) may represent a new and exciting type of immunotherapy in the treatment of primary childhood glial tumors.
 ...
PMID:Fas (Apo-1, CD95) receptor expression in childhood astrocytomas. Is it a marker of the major apoptotic pathway or a signaling receptor for immune escape of neoplastic cells? 1058 78


<< Previous 1 2 3 4 Next >>