Overexpression of the 18A2/mts1 gene and down–regulation of the TIMP–2 gene in invasive human glioma cell lines in vitro

Invasion of the reconstituted extracellular matrix composite, Matrigel, by eight human glioma–derived cell lines and human fetal brain cells was assessed in vitro using 8 um polycarbonate filters in a modified Boyden migration chamber. With the exception of one low grade glioma derived cell line, all lines studied proved to be invasive while normal fetal brain cells failed to invade. This invasive potential was independent of the histological grade of the tumour from which the cell lines originated. In addition, the expression of the metastasis–associated gene 18A2lmts1 as well as the tissue inhibitor of metalloproteinases–2 (TIMP–2) was analysed in each of the glioma–derived cell lines. The 18A2/mtsl was expressed in all the cells studied with the exception of fetal brain cells and the low grade non–invasive glioma derived IPRK–7 cell line. The 18A2/mtsl related genes coding for the S100 subfamily of calcium binding proteins were found to be differentially and overexpressed in invasive cell lines. TIMP–2 was expressed only in noninvasive cell lines. These results suggest that the 18A2/ mtsl and TIMP–2 genes could play an important role in the invasive behaviour of human glioma cells in vitro. .     

Vascular endothelial growth-factor production is stimulated in response to growth-factors in human glioma-cells

Neovascularization is essential for tumour growth and is mediated by physiological substances produced by tumours. Vascular endothelial growth factor (VEGF) is one such potent angiogenic factor. Human gliomas, the most important class of intrinsic brain tumours, express VEGF both in vivo and in vitro. Factors involved in the control of VEGF production by glioma cells are not well known. In this study, we investigated the role of basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), and platelet derived growth factors (PDGF) on VEGF production by four different glioma cell lines in vitro. With the exception of PDGF A/A and B/B in one cell line, all growth factors differentially stimulated VEGF production in all cell lines investigated. These data suggest that VEGF production in human glioma may be regulated by other growth factors which are also known to be expressed in such tumours.     

Expression of vascular endothelial growth-factor in the cyst fluid of human cerebral gliomas

Vascular endothelial growth factor (VEGF) or vascular permeability factor (VPF) has been shown to play a key role in angiogenesis in several solid tumours including human brain neoplasms. Its expression has also been found to be correlated to malignancy in the major class of these tumours, gliomas. Moreover, it has been suggested that cyst fluids (CFs) associated with human gliomas may contain a permeability factor responsible for the formation of brain edema and disruption of the blood-brain barrier generally observed in these tumours. We demonstrate that VEGF is present in low and high grade gliomas of seven patients. We also show that VEGF concentration increases with increasing malignancy of the tumours. Although further cases should be investigated, these results suggest that the amount of CF-VEGF may be of value in the diagnosis of human gliomas.     

Hyaluronic acid/CD44H interaction induces cell detachment and stimulates migration and invasion of human glioma cells in vitro

The mechanisms underlying the invasive properties of glio-mas, the major form of intrinsic brain tumours in humans, are poorly understood. We have reported that CD44 plays an important role in this behaviour in vitro. In the present work, we investigated the role of its ligand, hyaluronic acid (HA), in invasion in 8 human glioma cell lines. We found that HA mediates cell detachment via its interaction with its high affinity receptor, CD44H. Using 8 μm porosity polycarbonate filter transwells, we demonstrate that HA strongly stimulates migration in all 8 cell lines. This effect was found to be partially counteracted by a CD44H monoclonal antibody (MAb), suggesting the involvement of CD44H, as well as other HA receptors, in this process. Furthermore, incorporation of increasing concentrations of HA in Matrigel in an in vitro invasion assay resulted in a substantial increase in the invasive propensity of the glioma cell lines. Moreover, blocking experiments with the CD44H MAb suggest that CD44H and other receptors interact with HA to promote cell invasion in vitro. Our results show that HA induces cell detachment, stimulates migration and promotes invasion via its interaction with CD44H and other HA receptors in vrtro. These effects could be prevented by use of specific HA receptor antibodies.     

Gangliosides modulate proliferation,migration, and invasiveness of human brain tumor cells in vitro

Gliomas, the most common form of intrinsic brain tumor, are characterized by diffuse local invasion of the normal brain structures, irrespective of their histological grade of malignancy; a feature that is a major obstacle to successful therapy. They generally infiltrate the central nervous system (CNS) as individual tumor cells several centimeters beyond the macroscopic tumor margin and consequently often recur, after subtotal surgical resection. Factors involved in the control of both their proliferation and invasiveness are poorly documented. In this work, the role of gangliosides on proliferation of both human fetal human brain cells and five cell lines derived from human gliomas with different grades of malignancy was investigated. In addition, 8 μm-porosity polycarbonate filters were used to study cell motility. In addition, these filters were coated with the reconstituted extracellular matrix (ECM) composite, Matrigel, to assess invasiveness. The results presented show that gangliosides generally exert a proliferation inhibitory effect on fetal brain cells and glioma cell lines in vitro and play an important role in promoting glioma cell motility and invasiveness. The molecular mechanisms involved in the action of gangliosides may prove useful in identifying new targets for an anti-invasion therapy.     

Synergism between growth-factors in the control of glioma cell-proliferation, migration and invasion in-vitro

Gliomas constitute more than 50% of primary brain tumours in man. Perhaps the most important hallmark of these tumours is their diffuse invasion of the normal brain structures. The biological factors involved in the control of both their proliferation and invasion are, however, not well known. We studied the expression of receptors for epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), platelet derived growth factor (PDGF), and transforming growth factor beta-1 (TGF-beta 1) in low grade astrocytoma (IPNT-H)-, grade III astrocytoma (IPSB-18)-, and glioblastoma (IPRM-5)- derived cell lines. The effects of EGF, bFGF, PDGF, and TGF-beta 1 on proliferation, migration, and invasion in vitro were also investigated. When tested individually, EGF, bFGF and PDGF, were found to differentially stimulate proliferation, motility and invasion of the cell lines examined. When combined, these three growth factors acted synergistically to stimulate these biological properties. In addition, TGF-beta 1 exhibited positive and negative effects on the mitogenic action of the other growth factors in IPNT-H cells but inhibited their activity in IPSB-18 and IPRM-5 cells. Moreover, TGF-beta 1 was found to modulate negatively and positively the migration and invasion promoting action of the other growth factors in IPNT-H and IPSB-18 cells, while it strongly potentiated this action in IPRM-5 cells. These results suggest that all the growth factors examined may play key roles in the control of the biological properties of human glioma cells in vitro. Together with our findings that TGF-beta 1 is overexpressed in human glioblastoma in vivo, these results also suggest that co-operation between growth factors and TGF-beta 1 may be of central importance in tumour progression of gliomas.     

Déficit immunitaire commun variable (DICV) : caractéristiques cliniques et immunologiques de 29 patients algériens

Purpose

Common variable immunodeficiency (CVID) is the commonest symptomatic primary immunodeficiency. It is characterized by a defect of antibody production, recurrent respiratory tract infections and increased occurrence of auto-immune discords and lymphoproliferative disease.

Methods

This retrospective study was conducted on 29 patients fulfilling the classical CVID definition. Blood tests included immunoglobulin measurement and lymphocyte subpopulations phenotyping.

Results

This study includes 29 patients. The mean age at diagnosis was 23 years. Recurrent upper and lower bacterial respiratory tract infections were common in almost all patients. Five patients developed auto-immune conditions and six had lymphoproliferative disease. Decreased IgG was found in almost all patients. Low IgA and IgM levels were found in 89.6 % and 65.5 % of cases respectively. Abnormal T and/or B phenotype was found in 75 % of cases; the most common abnormalities were decreased circulating B (54.2 %) and T CD4+ (41.7 %) cells and inversion of the CD4/CD8 ratio (70.8 %). Patients with decreased circulating B and T CD4+ cells were significantly more likely to have auto-immune cytopenias and lymphoproliferative disease.

Conclusions

Our study confirms the heterogeneity of CVID. A patient's classification is necessary to define homogeneous groups of patients and to characterize specific molecular abnormalities in each group.