ABSTRACT
The participation of the main caspases in the cytotoxic effects induced by monoclonal antibody 14G2a specific against tumor-associated ganglioside GD2 was studied in the EL-4 cells. It has been found constitutive expression ofprocaspases genes in the EL-4 cells; incubation of the cells with 14G2a antibodies didnot result in increasing of the procaspases expression. Weak enzymatic activity of caspases has been shown using fluorescent labeled substrates. At the same cell death level, activity of caspase-3 and caspase-9 in the cells incubated with 14G2a was about 7.5- and 3-fold lower than in cells after incubation with staurosporine. Pan caspase inhibitor Z-VAD-FMK, and caspase-3 inhibitor reduced the cytotoxic effects induced by 14G2a at 9-16 and 6-13%, respectively. At the same conditions, pan caspase inhibitor decreased staurosporine-induced apoptosis at 55-65%. Inhibitors of other caspases had no effect on the cell death triggered by the antibodies. Inhibition analysis demonstrated also that caspases did not involved in the cell volume decreasing and permeabilization of the cell plasma membrane, which were the first stages of anti-GD2-mAb-induced cell death in the EL-4 cells. Thus, despite the slight activation of caspases during the cell death induced by antibodies directed to GD2, they do not play a key role and do not determine the mechanism of cell death triggered through the tumor-associated ganglioside GD2.
Subject(s)
Apoptosis/drug effects , Caspase 3/biosynthesis , Caspase 9/biosynthesis , Neuroblastoma/genetics , Antibodies, Monoclonal/administration & dosage , Caspase 3/genetics , Caspase 9/genetics , Caspase Inhibitors/administration & dosage , Cell Line, Tumor , Gangliosides/biosynthesis , Gene Expression Regulation, Neoplastic/drug effects , Humans , Neuroblastoma/enzymology , Neuroblastoma/pathology , Staurosporine/administration & dosageABSTRACT
We studied immunoregulatory properties of cultured human stem cells of mesenchymal and ectodermal origins after their administration to mice. Xenotransplantation of mesenchymal stem cells from human placenta reduced the number of CD11c(+)dendritic cells in mouse spleens, but did not affect activation of dendritic cells from mouse spleen in culture. It was also shown that splenocytes isolated from animals 10 days after transplantation of mesenchymal stem cells more actively proliferated in response to the polyclonal stimulation. At the same time, transplantation of neither mesenchymal nor neural stem cells affected the ratio of CD4(+)/CD8(+)T cells and their total content in the peripheral blood in comparison with the corresponding parameters in the control groups.
Subject(s)
Ectoderm/cytology , Mesoderm/cytology , Stem Cell Transplantation , Stem Cells/cytology , Stem Cells/immunology , Animals , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , Humans , Immunity, Cellular/immunology , Immunohistochemistry , Male , Mice , Mice, Inbred BALB CABSTRACT
The effects of human mesenchymal stem cells on neurological functions and behavioral reactions of animals and on damaged brain tissue were studied on the model of focal cerebral ischemia in rats. Homing and differentiation of transplanted mesenchymal stem cells were also studied. Significant regression of neurological disorders after cell transplantation was noted, no appreciable shifts were detected by magnetic resonance tomography. Homing of transplanted cells was detected mainly in the zone of focal ischemia. Some cells died, others exhibited signs of differentiation into neurons and glia.
