Anaplasia and Heterogeneity of Gfap Expression in Gliomas

GFAP (glial fibrillary acidic protein) distribution was investigated in selected areas of glioblastomas and astrocytomas. The proliferating cell population of glioblastomas was GFAP negative and contained many mitoses which were also negative. The old, deeply located areas were composed of cells with visible cytoplasm, intensely GFAP-positive; mitoses in these areas were both GFAP-positive and negative. GFAP-positive reactive astrocytes, once trapped in the tumor, were no longer distinguishable from positive tumor cells. They sometimes contained mitoses. In astrocytoma, anaplasia was due to the development of a GFAP-negative population with negative mitoses. The problem of dedifferentiation and differentiation of malignant gliomas in discussed taking into account the possiblity that malignancy may be due to increasing mutation rates of tumors. The problem of redifferentiation of already dedifferentiated cells is also discussed.

Composition of free amino acids in brain tumors

The composition of the free amino acid pools in various brain tumors and in normal brains obtained at surgery or at autopsy is determined with an automatic amino acid analyzer and the results statistically evaluated. The tumors have lower ratios of GABA in the pools than the normal brain; tumors with higher GABA ratios are found in those which are in close contact with and have an invasive nature to brain tissue. In gliomas, the more malignant a tumor becomes, the more different the composition in that tumor is from that in normal brain tissue. But conversely, the ratio of GABA is highest in glioblastoma. The composition of the pool in oligodendroglioma is not significantly different from that in the normal brain. Metastatic brain tumors show the highest ratios of phenylalanine, tyrosine and methionine in the pool among the tumors and the normal brain. From the viewpoint of the composition of the free amino acid pools, like from that of the histological aspects, brain tumors seem to be classified into four groups: glioma, neurinoma, meningioma and metastatic tumors.

Localization and characterization of endothelin receptors in human gliomas: a growth factor?

Localization and characterization of endothelin receptors in surgical specimens of human gliomas (6 benign astrocytomas and 7 glioblastomas multiforme) and in normal human cortices were studied using quantitative receptor autoradiographic methods. Low numbers of [125I]endothelin-1 [( 125I]ET-1) binding sites were detected in the gray matter of the human frontal cortex, with little binding in the white matter. Conversely, relatively high numbers of [125I]ET-1 binding sites were homogeneously present in tissue sections derived from astrocytomas, whereas higher numbers of [125I]ET-1 binding sites were heterogeneously located on groups of cells with a pseudopalisading appearance and pleomorphic astrocytes in glioblastoma multiforme. Necrotic areas within the tissue sections derived from glioblastoma were devoid of binding. Binding of [125I]ET-1 to gliomas and normal gray matter was specific. Unlabeled ET-1 and its natural analogs (ET-2 and ET-3) inhibited the binding of [125I]ET-1 to these lesions in a concentration-dependent manner and with similar high potencies. Possibly related substances, such as ion channel regulators (omega-conotoxin, apamin, and tetrodotoxin), a Ca2+ channel blocker (nicardipine), and growth factors (epidermal growth factor and insulin-like growth factor I), did not affect the binding to tissue sections derived from gliomas or from normal frontal cortices. Scatchard analysis revealed the presence of a single class and high-affinity binding sites for endothelin in normal cortex and in gliomas. There was no significant difference in the binding affinities: dissociation constants (Kd) were 2.1 +/- 0.5 nM in 6 astrocytomas, 2.5 +/- 0.4 nM in 7 glioblastomas, and 1.4 and 1.5 nM in two normal cortices.(ABSTRACT TRUNCATED AT 250 WORDS)

Silver colloid staining technique for analysis of glioma malignancy

A silver colloid staining technique for identifying nucleolar organizer region-associated proteins (Ag-NOR's) was applied to 51 human gliomas. These comprised 20 glioblastomas multiforme, 15 anaplastic astrocytomas, and 16 astrocytomas, in which the mean numbers of Ag-NOR's per cell (+/- standard error of the mean) were 2.51 +/- 0.12, 2.01 +/- 0.10, and 1.76 +/- 0.06, respectively. Significant differences among these were recognized, and the mean number of Ag-NOR's paralleled the degree of histopathological malignancy. In 16 cases, studies were performed of the number of Ag-NOR's and the S-phase fraction by in vitro labeling using antibromodeoxyuridine monoclonal antibody. A linear relationship was demonstrated between these two factors (r = 0.857, p less than 0.001), although some scatter was seen. In 32 adult patients, the correlation between the number of Ag-NOR's and the prognosis was estimated. The results demonstrated that the group containing patients with less than 1.80 Ag-NOR's per cell had a better prognosis than the group with 1.80 Ag-NOR's or more. Thus, the number of Ag-NOR's reflected the degree of histopathological malignancy, S-phase fraction, and prognosis. Silver colloid staining for Ag-NOR's is a simple, rapid, and reproducible method for estimating the proliferative potential of human gliomas without requiring a complicated technique.

Multiparameter flow cytometric analysis of neoplasms of the central nervous system: correlation of nuclear antigen p105 and DNA content with clinical behavior

Analysis of the DNA content of various solid tumors and hematological malignancies may provide useful prognostic information. To date, however, there has been a striking lack of correlation between DNA content in neoplasms of the central nervous system and clinical behavior. Simultaneous quantitation of DNA content and proliferation-associated nuclear antigen (p105) by flow cytometry was performed on paraffin-embedded tissues representing three major groups of central nervous system neoplasms--1) 21 astrocytic tumors, 2) 13 pituitary tumors, and 3) 19 meningiomas--and the results were correlated with clinical behavior. All 4 well-differentiated gliomas were diploid, while 3 of 9 anaplastic astrocytomas and 1 of 8 glioblastomas had a demonstrable aneuploid peak. Three of 13 pituitary tumors had an identifiable aneuploid peak, while only 2 of 19 meningiomas had an aneuploid DNA content. Cell-cycle analysis of the malignant gliomas revealed a significantly higher proliferative index (PI, %S + G2M) compared with the well-differentiated astrocytomas (P less than 0.05). Within the subgroup of diploid anaplastic astrocytomas, however, extended patient survival appeared to be associated with a higher PI. For diploid pituitary adenomas, the PI was consistently lower in the 3 tumors that recurred than it was in the remaining 8 adenomas. Nuclear antigen quantitation of diploid tumors showed a wide range of p105 expression in G0G1 cells, suggesting that, within each tumor, the cells are heterogeneous with respect to proliferative activity. Aneuploid nuclei of glial tumors showed enhanced expression of p105 relative to diploid cells of the same specimen. In pituitary tumors, the median G2M/G0G1 fluorescence ratio for p105 was significantly higher (P less than 0.05) for the 3 diploid recurrent tumors than for those that did not recur. These data support the assumption that the aggressive clinical course of malignant glial neoplasms may be related to an abnormal DNA stemline and/or an alteration in cell proliferative activity. Cell cycle analysis and measurement of p105 by this technique may provide information useful from both a prognostic standpoint and in directing adjuvant therapy.

Products of cells from gliomas: VIII. Multiple-well immunoperoxidase assay of immunoreactivity of primary hybridoma supernatants with human glioma and brain tissue and cultured glioma cells

To test the feasibility of primary screening of hybridoma supernatants against human glioma tissue, over 5000 combinations of hybridoma supernatants with glioma tissue, cultured glioma cells, and normal central neural tissue were screened with a new multiple-well (M-well) screening system. This is an immunoperoxidase assay system with visual endpoints for screening 20-30 hybridoma supernatants per single microscope slide. There were extensive differences between specificities to tissue and to cultured glioma cells when both were screened with M-wells and when cultured cells were screened with standard semi-automated fluorescence. Primary M-well screening with glioma tissue detected seven hybridoma supernatants that specifically identified parenchymal cells of glioma tissue and that were not detected with cultured cells. Immunoreactivities of individual supernatants for vascular components (nine supernatants), necrosis (five supernatants), and nuclei (three supernatants) were detected. Other supernatants bound multiple sites on glioma tissue and/or subpopulations of neurons and glia of normal tissue. The results show that primary screening with glioma tissue detects a number of different specificities of hybridoma supernatants to gliomas not detected by conventional screening with cultured cells. These are potentially applicable to diagnosis and therapy.

Attenuation of opioid receptor activity by phorbol esters in neuroblastoma x glioma NG108-15 hybrid cells

Chronic opioid treatment of neuroblastoma x glioma NG108-15 cells induces desensitization of the opioid receptor and this may involve a change in membrane protein phosphorylation. In an attempt to mimic this possible mechanism, we studied effects of phorbol ester activation of protein kinase C on opioid receptor activity. Incubation of NG108-15 hybrid cells with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) abolished up to 45% of opioid inhibition of cyclic AMP accumulation in intact cells, while basal accumulation and prostaglandin E1-stimulated cyclic AMP accumulation were unaltered. This decrease of opioid inhibition was dose- and time-dependent and the potency order of phorbol esters and apparent K activation (90 nM) for TPA were consistent with phorbol esters acting through the stimulation of protein kinase C. TPA also decreased the inhibition of cyclic AMP accumulation mediated through muscarinic and alpha-2 adrenergic receptors. These effects of TPA were best explained by a TPA-induced alteration of the inhibitory nucleotide-binding protein (Gi), the common transducer protein of these receptors. Impairment of Gi by TPA treatment was evidenced by a reduction in agonist-stimulated GTP hydrolysis and activation by GTP. Quantification of Gi by pertussis toxin-catalyzed ADP-ribosylation revealed that TPA decreased maximal labeling. In summary, phorbol esters appeared to attenuate opioid receptor activity by altering the activity of the transducer protein Gi.

[DAPI-DNA cytofluorometric study of glioma cells--application of DAPI-DNA cytofluorometry to paraffin embedded archival glioma tissue for nuclear DNA content analysis]

Using DAPI-DNA cytofluorometry, the author analyzed nuclear DNA content of formalin fixed, paraffin embedded, glioma material obtained from 14 glioma cases at surgery. Sections of 10 microns were deparaffinized. Following simultaneous DAPI (4,6-diamidino-2-phenylindole dihydroporphyrin chloride)/HP (hematoporphyrin) staining, DAPI binds DNA and DNA-DAPI complexes emit blue fluorescence when exited by ultraviolet (UV) light. Through Zeiss fluorescence microscope, the author measured nuclear fluorescence intensity with histological verification of glioma cells. A DNA histogram was obtained with fluorescence intensity recorded on the abscissa and number of cells plotted on the ordinate. Samples of 20 normal non-neoplastic astrocytes taken from apparently normal brain tissue included in the histological slide were used as diploid (2 C) control. Based on DNA content, tumor cells were classified into 4 groups: N-group composed of cells with 2 C DNA content (normoploid), S-group with less than 2 C (hypoploid), L-group more than 4 C (hypertetraploid), I-group between 2 C and 4 C (intermediate ploidy). Intermediate ploidy was significantly higher and normoploid was significantly lower in glioblastoma compared with those of benign astrocytoma. Thus, DNA content and histological malignancy were well correlated. Due to limitation of measuring diaphragm of turret in the microscope, some extra large cell could not be included in it and was excluded from the measurement.(ABSTRACT TRUNCATED AT 250 WORDS)

Suramin inhibits proliferation of rat glioma cells and alters N-CAM cell surface expression

Suramin, a drug used in the treatment of trypanosomiasis and onchocerciasis inhibits growth-factor-induced mitogenesis. We have investigated the effect of suramin on the growth rate and the morphology of C6 glioma cells cultured in the presence of serum or in a serum-free defined medium. Exponentially growing cells were seeded in multi-dish plates (5 x 10(4) cells/2 cm2 well) in DMEM supplemented with 5% fetal calf serum and were continuously exposed to 1 microgram/ml to 1,000 micrograms/ml suramin. Growth rate (determined 9 days after seeding) was reduced by 5%, 33%, 56% and 97%, respectively for suramin concentrations of 1, 10, 100 and 1000 micrograms/ml. Similar results were obtained in serum-free defined medium (DMEM/F12, 1:1, v:v, EGF 5 ng/ml, transferrin 5 micrograms/ml, selenium 10 ng/ml). Moreover, the concentration of suramin in the culture medium remained constant, demonstrating that the drug was not actively metabolized by the cells. Suramin also induced marked changes in cell morphology: the usual bipolar shape of C6 cells evolved toward a more differentiated appearance, with numerous cellular processes allowing a wide number of cell-cell contacts. In parallel, we monitored expression of an adhesion molecule (N-CAM) at both the mRNA and protein levels. Indirect immunofluoresence technique showed an important increase in cell surface N-CAM expression, starting from a dose of 10 micrograms/ml suramin, whereas total cellular content of N-CAM protein as well as its mRNA levels were unaffected. We also observed that the levels of expression of actin and N-CAM mRNAs decreased by a factor of two in cells maintained in defined medium. However, the relative ratio of N-CAM mRNA over actin mRNA was virtually unchanged following suramin treatment. Taken together, our results suggest that suramin (i) exerts a blocking effect of autocrine growth factors, (ii) interferes with the turn-over mechanisms of N-CAM expressed at the cell surface, either by impairing its endocytosis and/or the process of release of the N-CAM 120 isoform.

Cautionary note on the use of the B subunit of cholera toxin as a ganglioside GM1 probe: detection of cholera toxin A subunit in B subunit preparations by a sensitive adenylate cyclase assay

The use of the B subunit of cholera toxin, a protein that binds specifically to ganglioside GM1, has provided a new paradigm for studying physiological functions of ganglioside GM1. The B subunit inhibited the growth of rat glioma C6 cells that had been pretreated with ganglioside GM1. In some preparations of the B subunit, the inhibition was independent of adenylate cyclase activation and was due to the binding of the B subunit to ganglioside GM1 inserted onto the cell surface. However, in other preparations of the B subunit, there was an additional inhibitory effect due to small contaminations with the A subunit, which caused increases in intracellular cyclic adenosine monophosphate (cAMP) levels and concomitant growth inhibition. This vanishingly small contamination with the A subunit could not be detected by conventional protein sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis but could be measured utilizing a sensitive adenylate cyclase activation assay. Thus caution must be used to ensure that any biological effects of the B subunit are not due to contaminating A subunit and are due solely to the binding of the B subunit to ganglioside GM1 exposed on the cell surface. This is especially important in cyclic nucleotide-sensitive systems.

Sigma and opioid receptors in human brain tumors

Human brain tumors (obtained as surgical specimens) and nude mouse-borne human neuroblastomas and gliomas were analyzed for sigma and opioid receptor content. Sigma binding was assessed using [3H]1,3-di-o-tolylguanidine (DTG), whereas opoid receptor subtypes were measured with tritiated forms of the following: mu, [D-ala2,mePhe4,gly-ol5]enkephalin (DAMGE); kappa, ethylketocyclazocine (EKC) or U69,593; delta, [D-pen2,D-pen5]enkephalin (DPDPE) or [D-ala2,D-leu5]enkephalin (DADLE) with mu suppressor present. Binding parameters were estimated by homologous displacement assays followed by analysis using the LIGAND program. Sigma binding was detected in 15 of 16 tumors examined with very high levels (pmol/mg protein) found in a brain metastasis from an adenocarcinoma of lung and a human neuroblastoma (SK-N-MC) passaged in nude mice. kappa opioid receptor binding was detected in 4 of 4 glioblastoma multiforme specimens and 2 of 2 human astrocytoma cell lines tested but not in the other brain tumors analyzed.

Glomeruloid blood vessels in ethylnitrosourea-induced rat gliomas. Histological and immunohistochemical studies

Glomeruloid blood vessels (GBVs), a characteristic histological feature of most human malignant gliomas, were recognized with high incidence in autochthonous rat gliomas induced by transplacental administration of ethylnitrosourea. To evaluate some of the biological properties of these GBVs, we carried out a study using histological methods and immunohistochemical staining for glial fibrillary acidic protein, factor VIII-related antigen (VIII Ag) and bromodeoxyuridine (BrdUrd). Of 22 animals with large, massively growing gliomas in the CNS, GBVs including conglomerate aggregations of small blood vessels with endothelial hyperplasia and strong VIII Ag expression were observed in 13 large gliomas histologically consisting of primitive neuroepithelial neoplasms (PNN; so called ependymoma) and mixed-type gliomas in combination with astrocytoma and PNN or anaplastic astrocytoma. The anaplastic gliomas in our series were devoid of GBVs. These findings indicate that GBV formation takes place in a histological variety of experimental gliomas. Furthermore, the GBVs were frequently associated with the vasculo-mesenchymal stroma in the parent gliomas, suggesting an intimate relationship with the morphogenesis of GBVs. In addition, it was shown that the GBVs had a higher BrdUrd-labelling index than that of other blood vessels in gliomas and also that of neoplastic cells in most parent gliomas, except for anaplastic gliomas. Based on these results, the possible mechanism of GBV morphogenesis is discussed with regard to the roles of macromolecules in the induction and regulation of GBVs.

GD3 expression by cultured human tumor cells of neuroectodermal origin

Seven monoclonal antibodies (mAbs) reactive with ganglioside II3(NeuAc)2-LacCer (GD3) were generated; four of these mAbs (DMAb-21, DMAb-22, DMAb-23, and DMAb-24) by immunizing mice with GD3 adsorbed to Salmonella minnesota and the remaining three (DMAb-7, DMAb-8, and DMAb-17) with melanoma line SK-MEL 28, which contains 1.4 nmol sialic acid of GD3 per mg protein. The specificities of the mAbs were defined by high-performance thin-layer chromatography (HPTLC) immunostain and solid-phase radioimmunoassay (SP-RIA) with a panel of purified gangliosides. DMAb-7 and DMAb-8 reacted with GD3, IV3(NeuAc)2nLcOse4Cer(3',8'-LD1), and very weakly with IV3(NeuAc)2II3NeuAcGgOse4Cer (GT1a), but not with II3NeuAc-LacCer (GM3), II3NeuAcGgOse3Cer(GM2), II3NeuAcGgOse4Cer (GM1), II3NeuAc, IV3NeuAcGgOse4Cer (GD1a), II3(NeuAc)2GgOse3(GD2), II3(NeuAc)2GgOse4Cer (GD1b), IV3NeuAcII3(NeuAc)2, GgOse4Cer(GT1b), suggesting the binding epitope to be a terminal tetrasaccharide NeuAc alpha 2-8NeuAc alpha 2-3Gal beta 1-4(Glc or GlcNAc). DMAb-7 and DMAb-8 were used to investigate the expression of GD3 on cultured human tumor cells of neuroectodermal origin. Thirteen of 19 gliomas, 3 of 5 medulloblastomas, 5 of 5 neuroblastomas, 2 of 2 melanomas, and 1 of 3 teratomas were shown to react with DMAb-8 and/or DMAb-7 by cell surface-RIA (CS-RIA) and immunofluorescence (IF) assays. HPTLC and densitometric analysis confirmed these results, as positive immunostains in the GD3 region were obtained with oligoganglioside fractions from 9 glioma, 1 medulloblastoma, 2 neuroblastoma, 1 melanoma, and 1 teratoma cell line. Glioma cell line U-105 MG and medulloblastoma cell line Daoy contain GD3 as shown by HPTLC immunostain analysis of extracts, although GD3 was undetectable on the cell surface as determined by CS-RIA and IF.(ABSTRACT TRUNCATED AT 250 WORDS)

Isolation and partial purification of growth factors with TGF-like activity from human malignant gliomas

The effect of concentrated conditioned medium from each of eight human malignant glioma cell lines on the growth of indicator cells (normal rat kidney fibroblasts (NRK), clone 14) was determined in monolayer and in soft agar assay systems. The conditioned medium from all cell lines was mitogenic in the monolayer assay, but only SF-210, U-343 MG-A, and U-251 MG produced soluble factors that caused NRK cells to grow in soft agar. The soluble growth-promoting factors from these three cell lines were acid- and heat-stable (60 degrees C for 30 minutes) but were inactivated by trypsin (100 microns/ml) and dithiothreitol (50 microM). The growth factors from SF-210 and U-343 MG-A were further purified by molecular-sieve chromatography. The partially purified growth factor from U-343 MG-A retained transforming growth factor (TGF)-like activity, had a molecular weight of 9 kD, was potentiated by TGF-beta in the soft agar assay, competed effectively with 125I-epidermal growth factor (EGF) radiolabeled for the EGF receptor on A 431 epidermoid carcinoma cells, and was completely inhibited by monoclonal antibodies to TGF-alpha. The partially purified growth factor from SF-210 had a molecular weight of 17 kD, was not inhibited by monoclonal antibodies to platelet-derived growth factor (PDGF) or TGF-alpha, and did not bind to a heparin-Sepharose column. These results imply that U-343 MG-A secretes a growth factor with TGF-alpha-like activity, and SF-210 secretes a TGF with neither TGF-alpha nor TGF-beta activity.

Gliosarcoma: an immunohistochemical study

Gliosarcomas contain both neuro-ectodermal and mesenchymal elements. Its histogenesis has been much debated and endothelial and adventitial fibroblast origins have been suggested, as has a "histiocytic" origin following the demonstration of antiprotease activity. Eight gliosarcomas have been examined with a panel of ten monoclonal and polyclonal antibodies to investigate the origin of the sarcomatous element. Glial fibrillary acid protein expression showed a sharp distinction between gliomatous and sarcomatous tumour components. Contrary to some previous reports factor 8-related antigen and Ulex europeus agglutinin stained vascular luminal endothelium but no tumour cells. Vimentin and fibronectin expression was extensive and confined largely to sarcomatous areas. Desmin and neurofilament protein could not be demonstrated in any of the cases. Numerous cells, particularly in the sarcoma areas, expressed alpha-1-antitrypsin and -chymotrypsin. A proportion of these stained for the monocyte/macrophage marker MAC 387. Four cases focally exhibited a true storiform pattern and this and the immunohistochemical results suggest analogies with the fibrous histiocytomas. These tumours contain reactive histiocytes but are now thought to be derived from fibroblasts or from pluripotent mesenchymal cells in perivascular adventitia. This resembles the pattern exhibited in the sarcomatous component of gliosarcomas.

Immunosuppression and transforming growth factor-beta in glioblastoma. Preferential production of transforming growth factor-beta 2

Transforming growth factor (TGF)-beta 1 is a polypeptide that is assumed to play a fundamental role in the growth of both normal and neoplastic cells. TGF-beta 2 is a closely related polypeptide, originally described as glioblastoma cell-derived T cell suppressor factor (G-TsF) due to its immunosuppressive activity. Expression of the genes for TGF-beta 1 and G-TsF/TGF-beta 2 was examined in tumor cells and was found to be different in several cell lines and tissues that were tested. Whereas two glioblastoma cell lines expressed both TGF-beta 1 and G-TsF/TGF-beta 2 mRNA, one melanoma and neuroblastoma cell lines showed only TGF-beta 1 mRNA which in the case of the neuroblastoma required cycloheximide treatment for its detection. The coordinate expression of the genes for TGF-beta 1 and G-TsF/TGF-beta 2 in glioblastoma was not paralleled by secretion of both polypeptides as only G-TsF/TGF-beta 2 but not TGF-beta 1 was identified in supernatants of glioblastoma cells. These data provide evidence for a post-transcriptional level of regulation for production of the two forms of TGF-beta. As mRNA for G-TsF/TGF-beta 2 was also identified in fresh surgically removed human glioblastoma tissue, G-TsF/TGF-beta 2 may also be secreted within the tumor in vivo. Unlike glioblastoma, human fetal brain tissues or adult brain specimens studied did not express detectable levels of TGF-beta mRNA. Impaired cell-mediated immunity is an established finding in patients with glioblastoma. Secretion of G-TsF/TGF-beta 2 by tumor cells in vivo may contribute to decreased immune surveillance for tumor development, as well as neovascularization of the tumor tissue.

Immunolocalization of extracellular matrix proteins during brain tumor invasion in BD IX rats

The distribution of several native extracellular matrix proteins (type I, III, and IV collagens and fibronectin) using immunofluorescent localization is described for in two different malignant gliomas (BT4A and BT4An). In addition, antibodies against denatured forms of type I and III collagens were used to localize areas of active degradation within the tumors. We have shown that both tumors express the native connective tissue components studied, although the distribution of these components within and between the tumors was different. In addition, native type I and III collagens and fibronectin were overexpressed in the tumors compared to the normal brain. Morphometry on immunostained type IV collagen sections showed an increase in vascular elements in both tumors compared to normal brain tissue. The BT4A tumor, which by light microscopy showed a degradative mode of invasion, expressed denatured type I and III collagens at the tumor-brain border zone, suggesting that this tumor has collagenolytic activity. The present article suggests that the distribution and changes in extracellular matrix protein synthesis and degradation may play an important role in the progressive growth of brain tumors in vivo.

Immunocytochemical characterization of extracellular matrix proteins expressed by cultured glioma cells

The immunolocalization of type I, III and IV collagens and fibronectin in two rat glioma cell lines in vitro (BT4C and BT4Cn) is described. In addition, antibodies against denatured type I and III collagens were used to study breakdown products of native type I and III collagens. For the BT4C cells, the extracellular matrix expression in monolayer cultures and in multicellular tumor spheroids was compared. Type IV collagen was strongly expressed in BT4C tumor spheroids but was negative in the corresponding monolayer cultures. Denatured type I collagen was found both in monolayers and in spheroids of BT4C, suggesting either a rapid turnover (i.e., synthesis and immediate breakdown) of type I collagen or an altered collagen gene transcription. Both cell lines were negative for native type I and III and denatured type III collagen. Fibronectin was strongly expressed in both cell lines. Supporting the immunofluorescence data, the hydroxyproline content in the tumor spheroids was twice the amount found in monolayer cultures. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis combined with immunoblotting also verified the immunostaining experiments, showing that glioma spheroids and injected tumor cells have the potential for fibronectin and collagen production, given the appropriate growth conditions.

Identification of functional beta-adrenergic receptors on AC glioma cells

AC glioma cells, a clonal cell line derived from a rat glioma, responded to 1 mM dibutyryl-cyclic AMP and isobutylmethylxanthine with a change to stellate morphology. A concentration-related morphological change was induced by beta 1- and beta 2-adrenergic agonists with the order of potency being isoproterenol greater than soterenol greater than norepinephrine. Propranolol (nonselective, beta-antagonist), butoxamine (beta 2-antagonist) and metoprolol (beta 1-antagonist) significantly decreased the cell response to isoproternol. Schild analysis of the response, using the competitive antagonist metoprolol, gave pA2 values of 7.5 and 8.5 for the agonists norepinephrine and soterenol, respectively, with slopes of the curves being less than unity. These observations indicate that both beta 1- and beta 2-adrenergic receptors mediate the change in cellular morphology.

Experimental transplantation gliomas in the adult cat brain. 2. Pathophysiology and magnetic resonance imaging

In adult cats experimental brain tumours were produced by stereotactical xenotransplantation of the rat glioma clone F 98 into the internal capsule of the left hemisphere. Two to four weeks after transplantation tumours and peritumoural oedema were investigated by magnetic resonance imaging (MRI), electrophysiological recording and analysis of tissue content of water, electrolytes and extravasated serum proteins. Spherical tumours with a diameter of about 10 mm developed at the injection site and were surrounded by massive white matter oedema. Water content in peritumoural white matter increased from 2.63 +/- 0.17 to 3.65 +/- 0.19 ml/g d.w. (means +/- SD), sodium from 187 +/- 11 to 351 +/- 55 mueq/g d.w. and calcium from 7.4 +/- 1.1 to 13.3 +/- 1.3 +/- 1.3 mueq/g d.w. Potassium and magnesium did not change. Oedema development was associated with the extravasation of 18.0 +/- 16.8 mg/g d.w. albumin and 15.8 +/- 12.2 mg/g d.w. immunoglobulin. The calculated electrolyte content of oedema fluid approximated that of plasma but the serum protein content was about 40% lower. The ratio of low (albumin) to high (immunoglobulin) molecular weight proteins was the same in blood and oedema fluid. It is, therefore, concluded that peritumoural oedema consist of two components, a whole plasma extravasate and a protein-free ultrafiltrate. Peritumoural oedema could be clearly detected by MRI but differentiation between tumour and oedema was only possible after contrast enhancement with gadolinium-DTPA. The ratios of the intensities of the MR signal correlated linearly with the water content within white matter. MRI, in consequence, allows quantification of oedema provided a reference area with normal water content is present.

Labeling monoclonal antibodies and F(ab')2 fragments with the alpha-particle-emitting nuclide astatine-211: preservation of immunoreactivity and in vivo localizing capacity

alpha-Particles such as those emitted by 211At may be advantageous for radioimmunotherapy since they are radiation of high linear energy transfer, depositing high energy over a short distance. Here we describe a strategy for labeling monoclonal antibodies and F(ab')2 fragments with 211At by means of the bifunctional reagent N-succinimidyl 3-(trimethylstannyl)benzoate. An intact antibody, 81C6, and the F(ab')2 fragment of Me1-14 (both reactive with human gliomas) were labeled with 211At in high yield and with a specific activity of up to 4 mCi/mg in a time frame compatible with the 7.2-hr half-life of 211At. Quantitative in vivo binding assays demonstrated that radioastatination was accomplished with maintenance of high specific binding and affinity. Comparison of the biodistribution of 211At-labeled Me1-14 F(ab')2 to that of a nonspecific antibody fragment labeled with 211At and 131I in athymic mice bearing D-54 MG human glioma xenografts demonstrated selective and specific targeting of 211At-labeled antibody in this human tumor model.

Growth factors derived from a human malignant glioma cell line, U-251MG

A human malignant glioma cell line, U-251 Mg, cultured under serum free conditions, was shown to produce a growth factor for BALB/c 3T3 cells (glioma-derived growth factor-1, GDGF-1). The biological activity of GDGF-1 resided in a heat- and acid-resistant protein with a molecular weight (MW) of 25 kDa estimated by gel permeation chromatography. GDGF-1 activity was neutralized by a goat anti-human platelet derived growth factor (PDGF) antibody, indicating that the two factors were immunologically related. Furthermore, U-251 Mg cells constitutively expressed c-sis mRNA. When U-251 Mg cells were stimulated with bacterial lipopolysaccharide, 2 novel growth factors (GDGF-2 and GDGF-3) were produced in addition to the PDGF-like substance. GDGF-2 was determined to be greater than 100 kDa MW and was not neutralized by the goat anti-PDGF antiserum. The biological activity of GDGF-3 was also heat- and acid-resistant with an apparent 14 kDa MW. This factor also did not show any common antigenicity with PDGF. GDGF-2 and GDGF-3 are currently under investigation and evidence as to their natures will be published elsewhere. Our findings with this glioma cell line provide further evidence that inappropriate expression of growth factor-related genes could play important autocrine role(s) in the processes leading to malignant transformation and/or uncontrolled proliferation and may provide a paracrine stimulus for such processes as glioma neovascularization.

Expression of plasminogen receptors on C6 glioma cells

Plasminogen activators (PAs) play an important role in normal and neoplastic neuromorphogenesis in the central nervous system. Proper function of proteinases such as PA may require focusing of activity on a cellular level. In this study, we demonstrate that highly purified plasminogen binds to receptors on rat C6 glioma cells in culture. Specific binding is reversible and saturable at 4 degrees C. The Kd is 1.95 +/- 0.31 microM and the Bmax is 3.6 x 10(6) molecules/cell. At 37 degrees C, there is no evidence for ligand digestion or internalization. Plasminogen receptors may concentrate potential proteinase near membranes of glia during normal and neoplastic development in the central nervous system.

Noninvasive differentiation of tumors with use of localized H-1 MR spectroscopy in vivo: initial experience in patients with cerebral tumors

A recently developed method for image-selected localized hydrogen-1 magnetic resonance (MR) spectroscopy was assessed in the differential diagnosis of nine primary and secondary cerebral tumors, including four gliomas, two meningiomas, one neurilemoma, one arachnoid cyst, and one metastasis of breast cancer. Well-resolved H-1 MR spectra of these tumors were obtained in vivo with a conventional 1.5-T whole-body MR imaging system. All tumor spectra were remarkably different from spectra from normal brain tissue. Spectra obtained from different tumors exhibited reproducible differences, while histologically similar tumors yielded characteristic spectra with only minor differences. The observed spectral alterations reflect variations in concentrations and relaxation times of the H-1 MR sensitive pool of free (mobile) metabolites within the tissues. In most cases, the concentrations of N-acetyl-aspartate and creatine/phosphocreatine are reduced below detectability, whereas choline-containing compounds are generally enhanced. The spectral differences between the tumors are mainly due to the differing concentrations of lipids, lactic acid, and carbohydrates. Localized H-1 MR spectroscopy may become an important clinical tool for the differentiation of tumors as well as for therapeutic control.

Lipocortin-1 immunoreactivity in central and peripheral nervous system glial tumors

We examined the cellular distribution of lipocortin-1 (L-1), a major physiologic substrate for the epidermal growth factor receptor/kinase, in 122 central nervous system (CNS) and peripheral nervous system (PNS) neoplasms using the peroxidase-antiperoxidase technique with a polyclonal antibody specific for L-1. Extensive L-1 immunoreactivity was demonstrated in many CNS tumors; in 11 of 21 glioblastoma multiformes, in five of 12 anaplastic astrocytomas, and in five of 14 astrocytomas. Significant numbers of immunoreactive ependymocytes or astrocytes were also seen in six of 13 ependymomas. In contrast, no immunostaining was detected in the oligodendrocytes in any of ten oligodendrogliomas. PNS tumors, found in two of five malignant nerve sheath tumors, 13 of 15 schwannomas, 13 of 17 neurofibromas, and 14 of 15 traumatic neuromas, also contained considerable L-1 immunoreactivity in Schwann cells or mast cells. These findings raise the possibility that L-1 may participate in the proliferation or subsequent differentiation of neoplastic astrocytes, ependymocytes, and Schwann cells.

In vivo 31P nuclear magnetic resonance spectroscopy of rat 9L gliosarcoma treated with BCNU: dose response of spectral changes

The 9L gliosarcoma, grown subcutaneously in juvenile Fischer 344 rats, was studied by in vivo 31P NMR spectroscopy following treatment with 1,3-bis(2-chloroethyl)-1-nitrosourea. Dose-dependent increases in the proportion of high-energy phosphates were observed for doses between 10 and 36 mg/kg (from 80% of the LD10 to greater than the LD50). These doses reduced clonogenic cell survival in a dose-dependent fashion by as much as 3 log orders and resulted in up to 16 days of growth delay (to pretreatment tumor volume). Increases in high-energy phosphates (relative to Pi) in the tumor were greater at higher doses despite the higher levels of clonogenic cell killing and the substantial host systemic toxicity.

[Expression of insulin-like growth factor I receptors in human brain tumors: comparison with epidermal growth factor receptor by using quantitative autoradiography]

By using quantitative autoradiographic techniques, receptors for insulin-like growth factor I (IGF-I) and epidermal growth factor (EGF) were analyzed in 13 samples of human brain tumors (4 low grade astrocytomas, 7 glioblastomas, 1 anaplastic ependymoma and 1 medulloblastoma). High number of specific binding sites for IGF-I and EGF were homogeneously present in tissue sections derived from glioblastoma. In low grade astrocytoma, relatively high numbers of binding site for EGF were observed, but there was no significant difference in concentrations of IGF-I binding sites between tumors and control cortex. In medulloblastoma, only IGF-I binding sites were present. These observations might indicate that both IGF-I and EGF are involved in the growth modulation of human gliomas possibly through paracrine or autocrine mechanisms. Antagonists to growth factors or monoclonal antibody against those receptors could have the way for therapeutic application for gliomas.

Calmodulin content in human central nervous system tumors

Benign and malignant brain tumors and normal cerebral cortex were assayed for calmodulin content by enzymatic and radioimmunoassay techniques. Normal cerebral cortex contained more (8.31 +/- 1.27 vs 3.30 +/- 0.42 micrograms/mg protein) calmodulin than the brain tumors. The contents of calmodulin in the malignant glioblastomas were significantly higher than the meningiomas (5.41 +/- 0.31 vs 2.97 +/- 0.16 micrograms/mg protein). These differences were independent of tumor location and persisted when calmodulin content was normalized for DNA rather than protein content. This data supports differences in the tissue calmodulin contents with normal cortex greater than primary malignant tumors greater than benign tumors greater than metastatic tumor tissue.

Epidermal growth factor receptor in human glioma

Distribution of the epidermal growth factor (EGF) receptor in the surgical specimen of the human glioma was studied by immunohistochemical techniques using a monoclonal anti-EGF receptor antibody. Of 11 gliomas examined, EGF receptors were detected in nine glioblastomas and in one fibrillary astrocytoma. In the majority of cells, staining was observed over the cell membrane. Nuclear and cytoplasmic staining was also seen. In four glioblastomas, EGF receptor-positive cells were diffusely distributed in the tumor tissue. In one glioblastoma and one fibrillary astrocytoma, only a few positive cells were observed. These results imply the possible role of EGF receptors in the cellular proliferation of the human glioma.

[Analysis of the water-soluble protein fraction of glioma cells by two-dimensional electrophoresis]

The authors analyzed water-soluble proteins of culture human and rat glioma cells by two-dimensional polyacrylamide gel electrophoresis methods. Glioma cells were suspended in distilled water and then destroyed by freezing and thawing to obtain the water-soluble protein fraction. A modification of O'Farrell's non-equilibrium pH gradient (NEPHGE) method was used to analyze differences in protein mapping. Manabe's microscale two-dimensional electrophoresis without denaturing agents was used to detect proliferating cell nuclear antigen (PCNA/cyclin) by Western blotting. With O'Farrell's NEPHGE method and silver staining, at least 200 different polypeptides were clearly identified in each cell line. Cytoskeletal proteins, such as actin, were consistently separated in all cell lines. Marked differences in the protein map were observed between human and rat glioma cell lines, and even within the same species. Presumably, these differences are attributable to cell-biological difference in the glioma cells lines. Some proteins that were prominent in proliferating cells were scant in the protein maps of cells cultured for 24 hours in medium not containing calf serum, which suppresses cell growth. PCNA, an acidic nuclear protein that appears only in the late G1-S phase and is believed to be involved in cell proliferation, was detected by Western blotting and indirect immunostaining. Quantitative analysis of PCNA spots on the protein map appears useful in assessment of glioma cell proliferation. These results indicate that two-dimensional polyacrylamide gel electrophoresis can contribute to the understanding of the biological features of glioma cells.

Cytologic composition of the untreated glioblastoma with implications for evaluation of needle biopsies

To study the progression of astrocytic neoplasms and to provide practical information about the topography of the glioblastoma multiforme, the distribution of eight defined cell types was mapped from whole brain sections of 18 glioblastomas studied postmortem. Based on the densities and topographic distributions of well-differentiated and anaplastic cells, three principal categories of neoplasms were defined. In one group of three cases, multifocal glioblastomas appeared to be emerging in the background of a better differentiated, and presumably precursory, astrocytic neoplasm. In another group of nine cases, the neoplasms were more intimate mixtures of well and poorly differentiated cells. The third group of five cases was composed of neoplasms that were largely undifferentiated without a component of better differentiated cells. The study suggests that progression from a better differentiated neoplasm to one composed largely of undifferentiated cells is common in the fibrillary astrocytic neoplasms. Although some glioblastomas appear largely undifferentiated and consistent with the de novo appearance of overt malignancy, the size of these neoplasms and the patterns of necrosis leave open the possibility that a preexisting better differentiated neoplasm had been obliterated by necrosis and the overgrowth of the anaplastic component. The potential topographic variation of cellular constituency in a glioblastoma underscores the care that must be exercised in utilization of the needle biopsy technique in the diagnosis and grading of astrocytic neoplasms.

[Ultrastructural localization of ferritin in glioma]

In this study, we localized ferritin in 30 cases of glioma under electron microscope by using immunogold staining technique, and detected serum ferritin concentration in 25 patients with gliomas by the ELISA method. The results were as follows: Ferritin positives were mainly diffused in the cell sap, and the strongest immunostain was in the secondary lysosomes, while the endothelial reticulum and Golgi apparatus were rarely found to contain ferritin. Mitochondria and nucleus never had ferritin. Elevated level of serum ferritin was seen in glioma of grade II, III and IV, but the serum ferritin level of grade I remained normal. After resection of the tumor, serum ferritin decreased. These results suggested that the neoplastic cells of glioma could synthesize ferritin and release it to the exterior of the cells resulting in elevated serum ferritin, which may be helpful for clinical diagnosis, treatment and prognosis of glioma.

[Estrogen receptors in patients with brain tumors]

Estrogen receptor (ER) of brain tumors was assayed in 45 patients. In this series there were 39 cases contained ER, ranged from 0.7 to 188 fmol/mg protein of tumors (mean: 16.1 fmol/mg). The mean level of ER was 10.3 fmol/mg in 20 cases with meningiomas, 8.4 fmol/mg in 11 cases with gliomas, 51.1 fmol/mg in 5 cases with neurilemmomas, 10.5 fmol/mg in 3 cases with medulloblastomas, 16 fmol/mg in 2 organized hematomas due to ruptured AVM, 5.7 fmol/mg in a chordoma, 3.9 fmol/mg in a metastatic carcinoma from thyroid gland, and 0.8 fmol/mg in a cholesteatoma. The presence of ER in the latter several kinds of brain tumors have not been reported in previous literatures. The ER level of the tumors correlated with histological type of tumors, as well as the sex and age of the patients.

Altered expression and distribution of heparan sulfate proteoglycans in human gliomas

The expression of heparan sulfate proteoglycans (HSPGs) by human glioma cells was examined by biochemical and immunological methods in vitro and in vivo. Chondroitin sulfate was shown to represent the major [3H]glucosamine-labeled glycosaminoglycan synthesized by cultured normal brain cells. However, high-grade glioma-derived cells were shown to express significantly increased quantities of hyaluronic acid and heparan sulfate and approximately equal amounts of chondroitin sulfate compared with normal glial cells. To investigate further the differential expression of HSPGs, proteoglycans were isolated from glioma cells and were used as an immunogen to generate monoclonal antibodies (MAbs). One of these MAbs, 39H (an IgM), was shown to bind more to high-grade glioma-derived cells then to low-grade glioma or normal brain cells in vitro. MAb 39H was also observed to bind to isolated HSPGs but not to heparan sulfate glycosaminoglycan chains or trypsin-treated cells. Immunofluorescence staining of the cultured high-grade glioma cells revealed an intense diffuse cell surface staining pattern over the entire cell and also isolated footpads. In contrast, the low-grade tumor or normal glial cells showed a distinctive punctated staining. A similar differential staining of MAb 39H was most prominent between tissue sections of glioblastoma multiforme and anaplastic astrocytomas versus low-grade astrocytomas and normal brain. The low grade gliomas exhibited a weak punctated staining, whereas the high-grade gliomas showed significantly more intense staining, particularly along the apical regions of the cells. These results suggest that altered expression of HSPGs may be related to the malignant transformation or growth potential of glial-derived cells.

Isolation and partial characterization of a glial hyaluronate-binding protein

A glial hyaluronate-binding protein (GHAP) with an isoelectric point of 4.3-4.4 was isolated from human brain white matter. The 60-kDa glycoprotein appeared to be quite resistant to proteolysis, and comparison with GHAP from a viable glioma removed at surgery showed that the protein isolated from autopsy material was not a degradation product resulting from postmortem autolysis. The protein was localized immunohistochemically with mouse monoclonal and rabbit polyclonal antibodies in cerebral white matter. Only small amounts could be found in the gray matter. After enzymatic deglycosylation, an immunoreactive 47-kDa polypeptide was obtained. Two amino acid sequences of GHAP showed a striking similarity (up to 89%) with a highly conserved region of cartilage proteins (bovine nasal cartilage proteoglycan and rat and chicken link protein). However, the amino acid composition and other amino acid sequences suggested that there are also differences between brain-specific GHAP and cartilage proteins.

Purification and amino acid analysis of two human glioma-derived monocyte chemoattractants

Two chemoattractants for human monocytes were purified to apparent homogeneity from the culture supernatant of a glioma cell line (U-105MG) by sequential chromatography on Orange A-Sepharose, an HPLC cation exchanger, and a reverse phase HPLC column. On SDS-PAGE gels under reducing or nonreducing conditions, the molecular masses of the two peptides glioma-derived chemotactic factor 1 and 2 were 15 and 13 kD, respectively. Amino acid composition of these molecules was almost identical, and differed from other cytokines that have been reported. The NH2 terminus of each peptide was apparently blocked. When tested for chemotactic efficacy, the peptides attracted approximately 30% of the monocytes added to chemotaxis chambers, at the optimal concentration of 10(-9) M. Potency and efficacy were comparable with that of FMLP, which is often used as a reference attractant. The activity was chemotactic rather than chemokinetic. In contrast to their interaction with human monocytes, the pure peptides did not attract neutrophils. These pure tumor-derived chemoattractants can now be compared with attractants produced by normal cells and evaluated for their biological significance in human neoplastic disease.

Purification and amino acid analysis of two human glioma-derived monocyte chemoattractants

Two chemoattractants for human monocytes were purified to apparent homogeneity from the culture supernatant of a glioma cell line (U-105MG) by sequential chromatography on Orange A-Sepharose, an HPLC cation exchanger, and a reverse phase HPLC column. On SDS-PAGE gels under reducing or nonreducing conditions, the molecular masses of the two peptides glioma-derived chemotactic factor 1 and 2 were 15 and 13 kD, respectively. Amino acid composition of these molecules was almost identical, and differed from other cytokines that have been reported. The NH2 terminus of each peptide was apparently blocked. When tested for chemotactic efficacy, the peptides attracted approximately 30% of the monocytes added to chemotaxis chambers, at the optimal concentration of 10(-9) M. Potency and efficacy were comparable with that of FMLP, which is often used as a reference attractant. The activity was chemotactic rather than chemokinetic. In contrast to their interaction with human monocytes, the pure peptides did not attract neutrophils. These pure tumor-derived chemoattractants can now be compared with attractants produced by normal cells and evaluated for their biological significance in human neoplastic disease.

Endothelial cell growth factor derived from a human glioblastoma cell line and possible association with tumor angiogenesis

The cytosol of a human glioblastoma cell line (KNS-42) stimulated the growth of both bovine aortic endothelial cells and smooth muscle cells in a dose-dependent manner. The endothelial cell growth activity eluted at an apparent molecular weight of about 30,000 on a Sephadex G-100 column and bound to a heparin-Sepharose column with high affinity to elute at 1.3-1.7 M NaCl. The growth activity was destroyed by heating at 56 degrees C for 30 min, but not by exposure to trypsin, deoxyribonuclease or ribonuclease at 37 degrees C for 30 min. As this factor stimulated the growth of vascular endothelial cells and smooth muscle cells, and vasoproliferative responses in chick embryo chorioallantoic membranes were apparent, this factor may possibly be related to tumor angiogenesis.

[The composition of glycosphingolipids and the effect of neuraminidase on cultured glioma cell lines]

The composition of glycosphingolipid on human cultured glioma cell line U 251 and rat glioma cell line C6 was analysed by high performance thin layer chromatography. As a result, the major gangliosides were simple gangliosides such as GM3 (U 251: 7.7%, C6: 84.3%), GM2 (U 251: 32.6%) and SPG (U 251: 30.0%) on glioma cells whereas the major neutral glycosphingolipids were CDH, CTH and globoside. After treatment with neuraminidase 2.92 nmol/mg dry weight and 3.73 nmol/mg dry weight of sialic acid were freed from U 251 cells and C6 cell, but only 8.11% (U 251 cell) and 11.24% (C 6 cell) of these sialic acids originated from glycolipid, and thus the major part of sialic acid might be released from glycoprotein of the cells. The gangliosides that react to neuraminidase are SPG, GD1a and GD1b in U 251 cells and are GM1a and little GM3 in C 6 cells. The biolabelling study using N-acetyl-14C-mannosamine as a precursor of sialic acid demonstrated that the precursor was mainly incorporated into both or either of GM3 and SPG in the acidic glycolipid fraction. In addition, no significant change on proliferation and morphology of glioma cells after neuraminidase treatment was observed in this study.

[Morphological changes in basement membrane associated with endothelial proliferation in astrocytic tumors--an immunohistochemical study of laminin]

Morphological changes of the basement membrane associated with endothelial proliferation in astrocytic tumors are studied in this report. Laminin is known to be a specific glycoprotein of basement membranes. We applied this characteristic of laminin to enable us to observe various characteristics of the basement membrane. The presence of laminin in 13 glioblastomas, 15 anaplastic astrocytomas, 7 astrocytomas, and 6 pilocytic astrocytomas was examined by peroxidase-antiperoxidase (PAP) staining of formalin-fixed and paraffin-embedded surgical specimens. White matter from five normal cerebral hemispheres obtained during autopsy and subsequently embedded using the same method, were used as a control. Laminin was observed at the glioma-mesenchymal junction in astrocytic tumors, and the deposits of laminin made the tumor vasculature come into intense relief. The destructive changes of the basement membrane, including disruption, thickening, disconnection, dissociation, winding, and conjunction, became greater with progressive endothelial proliferation in astrocytic tumors. Those changes were seen to be most remarkable in glioblastoma. In addition, there was a marked variety of morphological change in the basement membrane in different areas of glioblastomas, although the changes were almost constant in other astrocytic tumors. We present a schematic hypothesis of the stages of angiogenesis in glioblastoma based on the above morphological changes of the basement membrane and discuss it in this report.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunohistochemical demonstration of immunoglobulins and albumin in human brain tumors

Routinely processed biopsy material, including 56 gliomas of varying malignancy, 10 meningiomas, 10 brain metastases and 12 brain abscesses, was examined for the presence and distribution of IgG, IgA, IgM, IgD and albumin using the unlabeled antibody peroxidase-antiperoxidase technique. In all specimens the deposition of stained immunoglobulins (Ig) was strictly associated with that of albumin even on cell surfaces. Thus there was no evidence for specific membrane binding or cytotoxicity. The interstitial proteins demonstrated are most likely derived from the plasma by blood-brain barrier breakdown which occurs in nearly all tumors and abscesses. Obvious intracellular staining for Ig and albumin was seen in glioma cells and astrocytes only. This is suggested to be due to active protein uptake as a specific feature of astrocyte differentiation which decreases with malignancy and is lost in glioblastomas. Evidence for local Ig production was found in 8 out of 10 metastases with striking IgG- and IgA-positive plasma cells within lymphocytic infiltrations and in one meningioma showing conspicuous plasma cells components. No glioma contained Ig-bearing plasma cells, though round cell infiltrations were present in 64% of the unselected cases. The significance of these findings regarding the immunological situation in brain tumors is briefly discussed.

Microspectrofluorometric evaluation of single- and double-stranded DNA in short-term cultured human glioma cells

Seven cerebral gliomas in short-term culture were studied by microspectrofluorometry and acridine orange staining to assess their nuclear content of single- and double-stranded DNA. Benign gliomas showed a diploid DNA pattern, whereas malignant gliomas revealed a higher frequency of DNA aneuploidy and hyperploidy. The content of single-stranded DNA remained relatively low in benign gliomas; however, that in malignant gliomas varied widely. After ACNU treatment, the double-stranded DNA histograms showed S-phase-specific accumulation in all cases but 1 with increasing concentrations of ACNU. The single-stranded DNA content decreased considerably in 2 cases, which responded well to chemotherapy and showed clinical amelioration.

Mesenchymal differentiation of cell lines obtained from human gliomas inoculated into nude mice

Tumor formation in nude mice (nu/nu Balb c outbred) inoculated with cells from four new permanent human glioma cell lines was studied. Three of these lines had previously been shown to display features of striated muscle in vitro. Histochemical and immunochemical techniques together with electron microscopic study confirmed that striated muscle differentiation continued to be expressed in vivo. Two of the cell lines arguably showed greater striated muscle differentiation in vivo, whereas one has lost this ability. In one of the two, further mesodermal differentiation was evident with the formation of cartilage.

Products of cells cultured from gliomas. VII. Extracellular matrix proteins of gliomas which contain glial fibrillary acidic protein

Extracellular matrix (ECM) components of two glial fibrillary acidic protein positive (GFAP+) glioma lines U251 and UM6 were studied by silver stain, morphometry, immunofluorescence, enzyme-linked immunosorbent assay, and biosynthetic labeling. Both GFAP+ lines expressed the following qualitative features in common with previously studied GFAP-negative gliomas: (a) laminin, (b) type IV collagen, (c) extracellular fibrils of silver-reducing collagen (d) pattern of reactivity with lectins. Quantitative differences in GFAP+ glioma proteins included less collagen and more laminin than GFAP-negative gliomas. Sparse collagen of GFAP+ gliomas aggregated as extracellular masses. Individual cells of UM6 simultaneously expressed GFAP and mesenchymal ECM components. Results show qualitative similarities of ECM expression among GFAP+ and negative gliomas suggesting a common lineage of these two glioma cell types and universal expression of two epithelial components of ECM, laminin and type IV collagen, among cultured gliomas. Moreover, there is a diversity of quantity and type of ECM proteins of GFAP+ gliomas with the U251 line most restricted in its expression of ECM components and with UM6 manifesting markers of epithelial and mesenchymal lineage. This diversity suggests a capacity for regulation of phenotypic expression of ECM beyond that explained simply by the presence of two cell types of different lineage.

Identification and structural analysis of the A type receptor for platelet-derived growth factor. Similarities with the B type receptor

Binding analyses using 125I-labeled platelet-derived growth factor (PDGF)-AA and PDGF-BB were used to identify a clonal human glioma cell line (U-343 MGa 31L) which expresses the A type but not the B type receptor for PDGF. The glioma cells were devoid of a B type receptor transcript, and immunoprecipitation with an antiserum raised against a B type receptor peptide rendered no signal. Similar analyses using human foreskin fibroblasts, which express both A and B type PDGF receptors, revealed a B type PDGF receptor-specific 5.5-kilobase pair mRNA in a Northern blot experiment, and 160,000 and 180,000 molecular weight components upon immunoprecipitation. A second antiserum, raised against purified porcine PDGF receptor preparations, was reactive with Mr 140,000 and 170,000 components in the U-343 MGa 31L cells, as well as in human fibroblasts. In addition, this antiserum precipitated the Mr 160,000 and 180,000 components from the fibroblasts. Exposure of cells to PDGF-AA, as well as to PDGF-BB, induced an increased rate of degradation of the Mr 170,000 component in the clonal glioma cells and in fibroblasts. The Mr 180,000 component in fibroblasts was degraded only when cells were exposed to PDGF-BB. This allowed the identification of the Mr 170,000 component as the cell surface expressed form of the A type receptor for PDGF. A structural relatedness between the A and B type PDGF receptors was furthermore indicated by similarities in peptide patterns, after limited proteolytic digestion.

Purification and partial characterization of a plasminogen activator inhibitor from the human glioblastoma, U138

A plasminogen activator inhibitor was purified to apparent homogeneity from conditioned media of U138 cells. The inhibitor is a glycoprotein with a pI of 5.4 and an apparent molecular weight of 45,000. The inhibitor forms sodium dodecyl sulfate-stable complexes with plasminogen activators and trypsin but not with plasmin, thrombin, or pancreatic kallikrein. Some biochemical and immunochemical characteristics of the U138 inhibitor distinguish it from other known plasminogen activator inhibitors. The expression of this inhibitor by U138 cells could be modulated by incubation in phorbol myristate acetate, interleukin-1, tumor necrosis factor, and gamma interferon, but not in beta interferon. Thus, the expression of the plasminogen activator inhibitor can be influenced by biological response modifiers known to be active in the brain and in the neural response to inflammatory stimuli. Therefore, this inhibitor, along with protease nexin, may be involved in brain development and regulation.

Glucocorticoids and the cell surface of human glioma cells: relationship to cytostasis

The glucocorticoid hormones methyl prednisolone and dexamethasone were shown to be cytostatic, but not cytotoxic, at high cell densities for early passage and continuous cell lines from human glioma at 0.25 microM and above, in the presence or absence of serum. In the absence of serum both steroids at 2.5 nM increased the saturation density close to the level reached in serum. Examination of the iodinated glycoproteins of the cell surface by gel electrophoresis did not reveal any consistent change. However, gel exclusion chromatography of protease digests of the cell surface and of material released into the medium showed an increase in incorporation of 3H-glucosamine in pronase digests after treatment with methyl prednisolone. Ion exchange chromatography showed that sulphated glycosaminoglycans, particularly heparan sulphate, increased and hyaluronic acid decreased in response to steroids, and there was increased retention of GAGs on the cell surface relative to the released fraction. It was concluded that glucocorticoid hormones modify the cell surface of human glioma cells and that this may contribute to enhanced cell intraction and lead to increased density limitation of cell proliferation.

[Immunohistochemical study of alpha-1-antichymotrypsin and GFAP in glioma]

GFAP is a specific antigen of glial element, but Alpha-1-antichymotrypsin has not been reported in the literature Alpha-1-antichymotrypsin was guided by GFAP using PAP method to the astrocytes of 137 gliomas. 120 (87%) gliomas were positive for Alpha-1-antichymotrypsin. Of these 120 gliomas, 86 (72%) gave diffuse distribution, 17 (14%) gave focal distribution, and 17 (14%) gave scattered distributions. Alpha-1-antichymotrypsin in glioma tissue may be an important tumor marker for diagnosis.