Heat Shock Protein HSP27 and the Status of the Glutathione System in Dexamethasone-Induced Apoptosis of Jurkat Tumor Cells.

We studied the effect of the HSP27 inhibitor, 5-(5-ethyl-2-hydroxy-4-methoxyphenyl)-4-(4-methoxyphenyl)-isoxazole, at a final concentration of 0.1 μM and/or the apoptosis inducer dexamethasone at a final concentration of 10 μM on the content of hydroxyl radical, reduced and oxidized glutathione, HSP27, activity of glutathione reductase, glutathione peroxidase, caspase-3, and the number of Annexin Jurkat tumor cells. The involvement of HSP27 in apoptosis of Jurkat tumor cells was demonstrated.

The Role of the Glutathione System in Oxidative Modification of Proteins and Dysregulation of Apoptosis in Jurkat Tumor Cells.

We compared changes in the redox status and intensity of oxidative modification of proteins in intact Jurkat tumor cells and cells cultured with buthionine sulfoximine, an inhibitor of the key enzyme of glutathione synthesis γ-glutamylcysteine synthetase. The glutathione system components play a role in modulation of the content of protein-bound glutathione, protein carbonyl derivatives, bityrosine, and oxidized tryptophan, and in dysregulation of apoptosis in Jurkat tumor cells. Inhibition of de novo synthesis of glutathione in Jurkat tumor cells was followed by accumulation of hydroxyl radical, a reduction in the level of protein-bound glutathione and oxidized tryptophan, and a rise in the concentration of protein carbonyl derivatives.

[Redox-dependent mechanisms of regulation of breast epithelial cell proliferation].

Activation of free radical oxidation in different cell types, including breast epithelial cells, may result in damage to macromolecules, in particular, proteins taking part in regulation of cell proliferation and apoptosis. The glutathione, glutaredoxin and thioredoxin systems play an essential role in maintaining intracellular redox homeostasis. Due to this fact, modulation of cellular redox status under the effect of an SH group inhibitor and an SH group protector may be used as a model for studying the role of redox proteins and glutathione in regulating cell proliferation in different pathological processes.

[The role of heat shock proteins 27 and 70 in redox-dependent regulation of apoptosis in Jurkat tumor cells].

Heat shock proteins Hsp) act as molecular chaperones, protecting enzymes and other proteins against reactive oxygen species. The objective of the study was to investigate the role of Hsp27 in maintaining the balance of the glutathione system and Hsp70 concentrations as well as in implementing Jurkat tumor cell apoptosis. Addition of the Hsp27 inhibitor KRIBB3 (5-(5-ethyl-2-hydroxy-4-methoxyphenyl)-4-(4-methoxyphenyl)-isoxazol) to Jurkat cells resulted in glutathione redox imbalance (increased GSSG and increased glutathione reductase activity), a decrease in Hsp70 concentrations, and also increased cell apoptosis as compared with to the intact cell culture.

The Role of Protein Oxidative Modification and the Cellular Redox Status in Realization of Apoptosis of MCF-7 Breast Adenocarcmoma Cells.

The aim of this study was to establish the role of redox modification of proteins and redox status in the realization of apoptosis of MCF-7 breast adenocarcinoma cells du-ing cultivation with the SH-group blocker N-ethylmaleimide (NEM) and the SH-group protector 1,4-dithioerythritol (DTE). The activation of apoptosis in MCF-7 breast adenocarcinoma cells was shown to be due to the irreversible modification of redox sensitive protein molecules. The presence of DTE in the culture medium of cancer.