Effects of grape seed extract in Type 2 diabetic subjects at high cardiovascular risk: a double blind randomized placebo controlled trial examining metabolic markers, vascular tone, inflammation, oxidative stress and insulin sensitivity.

OBJECTIVE: Current research has focused upon the potential links between novel markers of vascular risk such as endothelial dysfunction, oxidative stress, inflammation and insulin resistance in the pathogenesis of Type 2 diabetes and its complications. Grape seed extract (GSE), a flavonoid-rich product, is a potential moderator of these markers. This study aimed to test the hypothesis that GSE may improve these markers in high-risk cardiovascular subjects with Type 2 diabetes. RESEARCH DESIGN AND METHODS: Thirty-two Type 2 diabetes mellitus patients, prescribed diet or oral glucose-lowering agents, received GSE (600 mg/day) or placebo for 4 weeks in a double-blinded randomized crossover trial. Markers of endothelial function (measured by photoplethysmography), oxidative stress [total antioxidant status (TAOS), reduced glutathione (GSH)/oxidized glutathione (GSSG)], inflammation [highly sensitive C-reactive protein (hsCRP), urinary albumin : creatinine ratio), insulin resistance [homeostasis model assessment-insulin resistance (HOMA-IR)] and metabolism (fructosamine, lipid profile) was measured at baseline and after intervention with GSE or placebo. RESULTS: Baseline characteristics (16 male and 16 female): age 61.8 +/- 6.36 years; body mass index 30.2 +/- 5.92 kg/m2; diabetes duration 5.9 +/- 2.14 years. Following GSE (but not placebo), significant changes were noted in fructosamine (282 +/- 40.9 vs. 273 +/- 50.2 mmol/l; P = 0.0004); whole blood GSH (2359 +/- 823 vs. 3595 +/- 1051 mmol/l; P < 0.01) and hsCRP (3.2 +/- 3.65 vs. 2.0 +/- 2.2 mg/l; P = 0.0006). Total cholesterol concentration also decreased (4.5 +/- 0.96 vs. 4.3 +/- 0.99 mmol/l; P = 0.05). No statistically significant changes were shown in endothelial function, HOMA-IR or TAOS. CONCLUSION: GSE significantly improved markers of inflammation and glycaemia and a sole marker of oxidative stress in obese Type 2 diabetic subjects at high risk of cardiovascular events over a 4-week period, which suggests it may have a therapeutic role in decreasing cardiovascular risk.

The potential for strategies using micronutrients and heterocyclic drugs to treat invasive gliomas.

Local invasion of neoplastic cells into the surrounding brain is perhaps the most important aspect of the biology of gliomas that precludes successful therapy. Despite significant advances in neuro-imaging, neurosurgery and radiotherapy, the median survival for patients with a malignant glioma is still less than one year. With the increasing knowledge of the biology of brain tumours, derived from cellular and molecular studies, new methods of treatment are being developed with some success. Approaches studied already include anti-invasive, pro-apoptotic and anti-angiogenesis strategies and clinical trials are imminent. In this article we review two new approaches to the management of gliomas: nutraceutical intervention and heterocyclic drugs. The first approach uses a combination of naturally occurring agents, including citrus flavonoids, chokeberry extract, red grape seed extract, lycopene, selenium and red clover extract. These agents can either trigger apoptosis or affect the pathways underlying diffuse invasion. The second approach involves the use of a heterocyclic drug, clomipramine, which selectively triggers apoptosis in neoplastic cells but not in normal glia. The article refers to the results of recent studies performed in our laboratory which suggest that these new approaches can be translated into benefit to patients.

Tissue distribution and neuroprotective effects of citrus flavonoid tangeretin in a rat model of Parkinson's disease.

Neuroprotective effects of a natural antioxidant tangeretin, a citrus flavonoid, were elucidated in the 6-hydroxydopamine (6-OHDA) lesion rat model of Parkinson's disease (PD), after bioavailability studies. Following the chronic oral administration (10 mg/kg/day for 28 days), significant levels of tangeretin were detected in the hypothalamus, striatum and hippocampus (3.88, 2.36 and 2.00 ng/mg, respectively). The levels in the liver and plasma were 0.59 ng/mg and 0.11 ng/ml respectively. Unilateral infusion of the dopaminergic neurotoxin, 6-hydroxydopamine (6-OHDA; 8 microg), onto medial forebrain bundle significantly reduced the number of tyrosine hydroxylase positive (TH+) cells in the substantia nigra and decreased striatal dopamine content in the vehicle treated rats. Sub-chronic treatment of the rats with high doses of tangeretin (20 mg/kg/day for 4 days; p.o.) before 6-OHDA lesioning markedly reduced the loss of both TH+ cells and striatal dopamine content. These studies, for the first time, give evidence that tangeretin crosses the blood-brain barrier. The significant protection of striato-nigral integrity and functionality by tangeretin suggests its potential use as a neuroprotective agent.

The role of matrix metalloproteinase genes in glioma invasion: co-dependent and interactive proteolysis.

Matrix metalloproteinases (MMPs) are cation-dependent endopeptidases which have been implicated in the malignancy of gliomas. It is thought that the MMPs play a critical role in both metastasis and angiogenesis, and that interference with proteases might therefore deter local tumor dissemination and neovascularization. However, the attempt to control tumor-associated proteolysis will rely on better definition of the normal tissue function of MMPs, an area of study still in its infancy in the central nervous system (CNS). Understanding the role of MMP-mediated proteolysis in the brain relies heavily on advances in other areas of molecular neuroscience, most notably an understanding of extracellular matrix (ECM) composition and the function of cell adhesion molecules such as integrins, which communicate knowledge of ECM composition intracellularly. Recently, protease expression and function has been shown to be strongly influenced by the functional state and signaling properties of integrins. Here we review MMP function and expression in gliomas and present examples of MMP profiling studies in glioma tissues and cell lines by RT-PCR and Western blotting. Co-expression of MMPs and certain integrins substantiates the gathering evidence of a functional intersection between the two, and inhibition studies using recombinant TIMP-1 and integrin antisera demonstrate significant inhibition of glioma invasion in vitro. Use of promising new therapeutic compounds with anti-MMP and anti-invasion effects are discussed. These data underline the importance of functional interaction of MMPs with accessory proteins such as integrins during invasion, and the need for further studies to elucidate the molecular underpinnings of this process.

Evaluation of the effects of swainsonine, captopril, tangeretin and nobiletin on the biological behaviour of brain tumour cells in vitro.

Although intrinsic tumours of the brain seldom metastasize to distant sites, their diffuse, infiltrative-invasive growth within the brain generally precludes successful surgical and adjuvant therapy. Hence, attention has now focused on novel therapeutic approaches to combat brain tumours that include the use of anti-invasive and anti-proliferative agents. The effect of four anti-invasive agents, swainsonine (a locoweed alkaloid), captopril (an anti-hypertensive drug), tangeretin and nobiletin (both citrus flavonoids), were investigated on various parameters of brain tumour invasion such as matrix metalloproteinase (MMP) secretion, migration, invasion and adhesion. A standard cytotoxicity assay was used to optimize working concentrations of the drugs on seven human brain tumour-derived cell lines of various histological type and grade of malignancy. A qualitative assessment by gelatin zymography revealed that the effect of these agents varied between the seven cell lines such that the low grade pilocytic astrocytoma was unaffected by three of the agents. In contrast, downregulation of the two gelatinases, MMP-2 and MMP-9 was seen in the grade 3 astrocytoma irrespective of which agent was used. Generally, swainsonine was the least effective whereas the citrus flavonoids, particularly nobiletin, showed the greatest downregulation of secretion of the MMPs. Furthermore, captopril and nobiletin were most efficient at inhibiting invasion, migration and adhesion in four representative cell lines (an ependymoma, a grade II oligoastrocytoma, an anaplastic astrocytoma and a glioblastoma multiforme). Yet again, the effects of the four agents varied between the four cell lines. Nobiletin was, nevertheless, the most effective agent used in these assays. In conclusion, the differential effects seen on the various parameters studied by these putative anti-invasive agents may be the result of interference with MMPs and other mechanisms underlying the invasive phenotype. From these pilot studies, it is possible that these agents, especially the citrus flavonoids, could be of future therapeutic value. However, further work is needed to validate this in a larger study.

The effects of exogenous growth factors on matrix metalloproteinase secretion by human brain tumour cells.

Matrix metalloproteinases (MMPs) are a growing family of zinc-dependent endopeptidases that are capable of degrading various components of the extracellular matrix. These enzymes have been implicated in a variety of physiological and pathological conditions including embryogenesis and tumour invasion. The synthesis of many MMPs is thought to be regulated by growth factors, cytokines and hormones. In this study, we investigated the effects of five exogenous growth factors known to be expressed by gliomas [epidermal growth factor (EGF), basic growth factor (bFGF), transforming growth factor beta (TGF-beta1,2) and vascular endothelial growth factor (VEGF)].on MMP-2 and MMP-9 expression in an ependymoma, two grade III astrocytomas, a grade III oligoastrocytoma and a benign meningioma. Zymogram analysis revealed that the effects of the growth factors depended upon the cell lines used in the study. Growth factors generally up-regulated MMP-2 and MMP-9 expression in the gliomas but were least effective in the meningioma; the effect being most prominent with TGF-beta1 and TGF-beta2 in all the cell lines. It is hypothesized that paracrine growth factor interplay may be crucial in the regulation of MMP expression by glioma invasion of the normal brain.

The NG2 chondroitin sulfate proteoglycan: role in malignant progression of human brain tumours.

The expression and function of NG2, a transmembrane chondroitin sulfate proteoglycan was studied in human gliomas of various histological types in culture using immunocytochemistry and flow cytometry. NG2 was differentially expressed in the neoplasms, with higher expression in high compared to low-grade gliomas. In acutely isolated cells from human biopsies, NG2 +ve and NG2 -ve populations were morphologically distinct from each other, and NG2 +ve cells were more proliferative than NG2 -ve cells. The mitogens platelet derived growth factor (PDGF-AA) and basic fibroblast growth factor (bFGF) added in combination to serum-free medium (SFM) upregulated NG2 expression on glioblastoma multiforme cells in culture but had little effect on NG2 expression on the anaplastic astrocytoma cells. Furthermore, NG2 was colocalised with the platelet derived growth factor alpha receptor (PDGFalphaR) and antibody blockade of the PDGF-alphaR ablated NG2 expression on the glioblastoma multiforme cells, suggesting that increased NG2 expression in the presence of PDGF-AA is mediated via the PDGF-alphaR. Assays of migration and invasion indicate that NG2 +ve glioma cells migrated more efficiently on collagen IV and that NG2 -ve cells were more invasive than their NG2 +ve counterparts. The results indicate that NG2 may be, respectively, positively and negatively related to the proliferative and invasive capacity of glioma cells. Thus, expression of the NG2 proteoglycan may have major implications for malignant progression in glial neoplasms and may prove a useful target for future therapeutic regimens.

The role of integrin receptors in aspects of glioma invasion in vitro.

Integrins are heterodimers consisting of non-covalently associated alpha and beta subunits. They mediate adherence of normal and tumour cells to the extracellular matrix, a property which is essential for migration of neoplastic astrocytes as they invade into the normal brain parenchyma. Flow cytometry and immunocytochemical analysis of cultured cells derived from 10 gliomas (1 pilocytic astrocytoma, 1 astrocytoma, 1 oligoastrocytoma, 1 anaplastic oligoastrocytoma, 4 anaplastic astrocytomas and 2 glioblastoma multiforme) revealed that the beta1 integrin subunit was generally expressed more strongly than alpha4 or alpha(v) integrin subunits. Subsequent studies with function-blocking antibodies against the beta1 subunit inhibited adhesion, motility and invasion of the gliomas in vitro, to varying degrees, on all extracellular matrix substrates investigated (laminin, collagen type IV, fibronectin and vitronectin), the inhibition by beta1 subunit was greatest on collagen type IV. These studies therefore substantiate the case for a role of the beta1 integrin subunit in neoplastic glial cell invasion of the brain.

CD44 expression in human meningiomas: An immunocytochemical, immunohistochemical and flow cytometric analysis.

CD44 is a polymorphic family of cell adhesion molecules that has been implicated in tumour invasion and metastasis. In this comparative analysis study, we investigated the expression of the standard form of CD44 (CD44s or CD44H) in 25 early passage cultures of meningiomas and histological sections, using immunohistochemical, immunocytochemical and flow cytometry techniques. There were 20 grade I, 3 grade II and 2 grade III meningiomas in the study which also included 2 recurrent meningiomas and 1 meningioma arising some time after previous radiotherapy. Immunocytochemistry and flow cytometry results on early passage culture cells show that although the majority of the meningiomas were strongly positive for CD44H, some were only weakly positive. Immunohistochemical studies revealed a great variability in staining patterns both within individual tumours and between different tumours. Generally, the intensity varied between strong and negative, and in most tumours that were immunopositive, there was a multifocal pattern of staining. Five meningiomas did not stain at all for CD44H. Taken together, these findings suggest that generally the flow cytometry results correspond well with those of both immunocytochemical and immunohistochemical techniques, with a few exceptions. It is concluded that microenvironmental factors may be responsible for the differential expression seen with different techniques.

Extracellular matrix-modulated differential invasion of human meningioma cell lines in vitro.

The in vitro invasive behaviour of six meningioma cell lines of various histological sub-type and grade was assessed using Boyden chemotaxis chambers ('Transwell' units) precoated with various extracellular matrix proteins. The cell lines included a benign meningothelial (IPGS), two benign transitional (IPCBR and IPGC), one atypical (IPIH) and two malignant (IPSE and IPIR) meningiomas. IPGC was a recurrent tumour. The results showed that IPCBR was most invasive through laminin and vitronectin. IPIH was moderately invasive through collagen type IV, laminin, vitronectin and fibronectin. However, both IPSE and IPIR were less invasive than IPIH whereas, IPGS was least invasive of all. Moreover, laminin was the most permissive extracellular matrix protein for most cell lines and collagen type IV, the least permissive. These results show that there is a differential in vitro invasive behaviour of cell lines derived from different histological types of meningiomas according to extracellular matrix substrate and suggests that invasion and migration of meningiomas in situ might be modulated by various extracellular components.

Comparative analysis of matrix metalloproteinases by immunocytochemistry, immunohistochemistry and zymography in human primary brain tumours.

Matrix metalloproteinases (MMPs) are a growing family of zinc-dependent endopeptidases which are characterised by their ability to degrade various extracellular matrix (ECM) components. The family includes collagenases, gelatinases, stromelysins, metalloelastase and membrane type metalloproteinases. Consistent with their proteolytic activities, MMPs have been implicated in a variety of physiological and pathological conditions, such as normal embryogenesis, tissue morphogenesis and are thought to play a role in facilitating tumour cell invasion of the normal brain. In this comparative study, we have used zymography, immunohistochemical and immunocytochemical techniques to demonstrate the expression of gelatinase-A and B (MMP-2 and 9, respectively) and membrane type metalloproteinase (MMP-14) in 8 intrinsic human primary brain tumours of various histological type and grade. Zymography results showed that MMP-2 was the most prominent proteolytic enzyme in all the cell lines studied (with one exception), while MMP-9 was only faintly expressed. However, the corresponding paraffin sections showed no expression of either MMP-2, 9 or 14 within the tumour cells, positivity being confined to haematogenous cells and the vascular endothelium. Fluorescence immunocytochemical studies, using monoclonal antibodies to MMP-2, 9 and 14, showed granular cytoplasmic reactivity in vitro. In addition, there was strong focal positivity at the cell membrane with MMP-14 in some high grade tumours suggesting that MMPs are produced at the leading edge of the cell by individual subpopulations of invading glia, in small quantities and on demand in vivo. It can be concluded that local microenvironmental conditions in vitro appear to stimulate such MMP activity.

An inverse correlation between expression of NCAM-A and the matrix-metalloproteinases gelatinase-A and gelatinase-B in human glioma cells in vitro.

Matrix metalloproteinases (MMPs) are an homologous family of proteolytic enzymes capable of degrading components of the extracellular matrix (ECM) and thereby facilitating the invasion of tumour cells into normal tissues. The neural cell adhesion molecules (NCAMs) of neuronal and glial cells provide a Ca2+-independent mechanism for cell-cell and cell-ECM adhesion. NCAMs are downregulated to promote cell disaggregation during cell migration in the developing nervous system whereas MMPs facilitate migration. Recent studies have shown downregulation of MMP secretion in rat glioma cells transfected with an NCAM cDNA, implying an inverse correlation between NCAM and MMP expression. The purpose of this study was to establish whether such a correlation could be demonstrated in a panel of nine human glioma cell-lines, one metastatic carcinoma and one foetal astrocyte derived cell line. The secretion of two MMPs, 72 kDa gelatinase (MMP-2 or gelatinase-A) and 92 kDa gelatinase (MMP-9 or gelatinase-B), was investigated using SDS-PAGE zymography; NCAM-A was assayed by an immunochemiluminescent assay following SDS-PAGE of whole-cell extracts. An inverse correlation was found between the expression of NCAM-A and that of both MMPs studied although the patterns of expression showed no obvious correlation with histological type or grade of the parent tumours. Our results suggest that downregulation of NCAM-A may contribute to tumour invasiveness by promoting both cell disaggregation and protease secretion.

The effect of acetaldehyde on human brain transketolase activity.

Chronic alcoholism and thiamine deficiency are well documented factors in the aetiology of Wernicke-Korsakoff Syndrome. More recently, acetaldehyde (ACH) has been implicated as a possible aetiological factor. In the present investigation the direct effect of ACH was studied on the activity of transketolase, a thiaminedependent enzyme, as well as two non-thiamine-dependent enzymes (aspartate aminotransferase and lactate dehydrogenase), isolated from five control human brains. The concentration of ACH required to inhibit 50% activity of holo- and apo-transketolase was 80 mM and 60 mM, respectively, whereas that for aspartate aminotransferase and lactate dehydrogenase was 14 mM and 10 mM, respectively. None of the enzymes were completely inhibited by the range of ACH concentrations used in the study. It was concluded that the thiamineindependent enzymes were markedly affected by the concentrations of ACH which did not affect the thiaminedependent enzyme, transketolase. In vitro studies with homogenates pre-treated with ACH in the presence of various concentrations of glutathione showed that the latter had a protective effect against loss of transketolase activity.

Correlation of expression of NCAM and GD3 ganglioside to motile behaviour in neoplastic glia.

Studies of developing mammalian tissues have established that certain neural cell adhesion molecules (NCAMs) may be down-regulated during the migratory phase concurrent with an increase in levels of matrix metalloproteinases. In addition, there is evidence that simple gangliosides such as GD3 are transiently present on the surface of such migratory cells. Since migration, or motility, is a prerequisite for diffuse local invasion of brain by neoplastic cells, the expression of NCAM and GD3 on brain tumour cells was studied in order to establish their possible role in the invasive process. An astrocytoma parent cell line (IPSB-18) and two morphologically distinct, cloned cell lines (clone 1 and 12) derived from it, were used in in vitro motility assays using 8 microns porosity polycarbonate filters in "Transwell" modified Boyden chambers. Immunocytochemical staining with anti-NCAM monoclonal antibodies (UJ13A and ERIC-1) and with the anti-ganglioside monoclonal antibodies LB1 (which recognises GD3) and A2B5 (which recognises a range of simple gangliosides) showed that some cells in culture from the parent line were positive for either NCAM or GD3; clone 1 was NCAM positive but GD3 negative, while clone 12 was NCAM negative but ganglioside positive. Motility assays showed that although clone 12 migrated more efficiently than either clone 1 or the parent line, this was not statistically significant. Moreover, similar assays were conducted on two further sub populations of cells which were evolved from the immunomagnetic separation of the parent cell line, IPSB-18, according to NCAM expression (i.e. NCAM positive and NCAM negative). The results indicated that the NCAM negative cells migrated more efficiently than the NCAM positive cells, in a time-dependent manner, when incubated for 4, 12 and 18 hours in Boyden chambers. These findings suggest that during the migratory phase of brain tumour invasion, NCAM expression is down-regulated whereas ganglioside expression is up-regulated.

Establishment and characterization of two paediatric brain tumour cell lines in vitro.

Well-characterised, established cell lines derived from paediatric brain tumours are rare. The paucity of medulloblastoma cell lines may reflect--at least in part--the differences in cell adhesion molecule expression between the cells of primitive neoplasms of childhood and their better-differentiated adult counterpart neoplasms. This frequently results in primitive neoplastic cells failing to adhere to the culture dish substrate and leads to suspension, rather than monolayer, growth. Furthermore, low grade astrocytic neoplasms of infancy and early adulthood often have low mitotic indices and, accordingly, fail to establish themselves in vitro. We report here the establishment and characterisation of a surface adherent medulloblastoma-derived cell line (IPNN-8) from a 13 year old boy and a pilocytic astrocytoma of the hypothalamus-derived cell line (IPNT-H) from a 6 month old child which have undergone 39 and 36 serial passages respectively. Growth curves and PCNA staining results show that these cell lines have similar population doubling times (24 hours and 27 hours respectively) and high proliferative indices. Immunocytochemical analysis shows that the IPNN-8 cell line is weakly positive for NFP and S-100 protein and negative for both NSE and CD44 but positive for A2B5 and GFAP, indicating glial differentiation; whereas, the IPNT-H cell line is positive for GFAP, glutamine synthetase, A2B5 and CD44 but only weakly positive for vimentin.

Proteases and their inhibitors in human brain tumours: a review.

Proteases such as matrix metalloproteinases (MMPs), cysteine- and serine-proteinases are capable of degrading extracellular matrix and basement membranes and have been implicated in human brain tumours. MMPs are a homologous family of zinc-dependent proteases. Within this group, attention has been focused on the gelatinases (MMP-2 and MMP-9) which are thought to play an important role in tumour progression. The cysteine proteinases which have received most attention in relation to tumour progression are cathepsin B (CB) and to a lesser extent cathepsin L (CL). Among the serine proteinases, urokinase plasminogen activator and its receptor have been the subject of much investigation. In the present review, evidence from current literature on the possible role or significance of serine- and cysteine-proteinases and MMPs and their inhibitors in human brain tumours is discussed with special reference to gliomas. Although direct evidence is reported for MMPs and serine proteinases to support their role in glioma invasion, much of the evidence for the involvement of cysteine proteinases remains circumstantial.

Thiamine pyrophosphate effect and normalized erythrocyte transketolase activity ratio in Wernicke-Korsakoff patients and acute alcoholics undergoing detoxification.

Thiamine deficiency may be assessed clinically by an abnormally low specific erythrocyte transketolase activity and/or by abnormally large activation by thiamine diphosphate in vitro (or 'TPP effect'). In the present investigation, we report erythrocyte transketolase activation by TPP in acute alcoholics and Wernicke-Korsakoff patients undergoing detoxification. A new age-dependent parameter was used to improve the reliability of transketolase activity as an indicator of marginal thiamine deficiency. Thus normalized transketolase activity ratio (NTKZ), primary activation ratio (PAR) and further activation ratio (FAR) were measured in 29 acute alcoholics and 12 Wernicke-Korsakoff patients upon admission, and also on 47 control subjects. It was possible to follow up 14 of the 29 acute alcoholics after 7 days of treatment. Twenty-one per cent of the acute alcoholics and 33% of the Wernicke-Korsakoff patients, on admission to the detoxification Unit, had NTKZ values beyond the defined critical conditions for thiamine deficiency, whereas 7% of the former and 25% of the latter had PAR values beyond these critical conditions. Furthermore, all three parameters were significantly different in the Wernicke-Korsakoff patients compared to the other groups. The pattern of improvement of the different parameters on follow-up varied considerably and is difficult to explain, as only the NTKZ was statistically significant. Hence, only eight out of 14 acute alcoholics showed improvement in NTKZ, seven showed improvement of PAR and six showed improvement of FAR after treatment. Five patients showed improvement of both NTKZ and PAR and none of the patients showed improvement of all three parameters. We conclude that our findings confirm previous reports and that this modified transketolase activation test improves its reliability as an indicator of marginal thiamine deficiency.

The effect of exogenous gangliosides on matrix metalloproteinase secretion by human glioma cells in vitro.

Matrix metalloproteinases (MMPs) are zinc-dependent peptidases and are amongst those enzymes responsible for extracellular matrix (ECM) degradation during tumour-cell migration. Gangliosides are a family of acidic membrane glycolipids thought to play a role during cell development, differentiation and oncogenic transformation. In this descriptive study, we investigated the effects of six exogenous gangliosides (GM1, GM3, GD1a, GD1b, GD3 and GT1b) on the secretion of MMP-2 (72 kDa gelatinase or gelatinase-A) and MMP-9 (92 kDa gelatinase or gelatinase-B). Cell-conditioned media from eight human glioma-derived cell-lines served as the source of MMPs and were investigated using SDS-PAGE zymography. Six of the cell lines showed upregulation of secretion of both enzymes by all six gangliosides. Of the remaining two cell lines, one showed inhibition of MMP secretion by all gangliosides and the other had a small but differential response to the range of gangliosides investigated. These results suggest that gangliosides may stimulate glioma cell invasiveness by promoting MMP expression.