[Possible mechanism of the selective action of the inhibitors of glycolysis in the endothelial cells and the human carcinoma cells in the culture].

It is known that the production of energy and synthesis of macromolecules in cancer cells depend on the glucose metabolism to a greater extent than in non-tumor. In this paper we carry out a comparative study of the effectiveness of the two modifiers glycolysis 2 - D-deoxyglucose (2-DG) and dichloroacetate (DCA) in the induction of the cell death, changes in the cell cycle progression and in the alteration of the intracellular ROS levels in endothelial cells (line ECV304) and human carcinoma cells (line HeLa G-63) in order to identify cause-effect relations between these events. It has been shown that inhibition of the various stages of the glycolysis result in blocking cells in C2/M phase of the cell cycle and the induction of the cell death. This effect was record for HeLa G-63 cells only. DCA is inhibitor of the pyruvate dehydrogenase kinase and 2-DG is inhibitor of the glucose transport and glycosylation induced selective dose-dependent cytotoxic effect in HeLa G-63 cells. The increase of intracellular levels of the oxygen radicals induced by DCA in the cells HeLa G-63 suggests that the cytotoxic effect of the DCA is mediated by activation of the mitochondrial functions. The cytotoxic effect of 2-DG depend on the level of glucose in the culture medium, therefore we suggest that not only the oxidative stress, but and the energy depletion involved in selective response of the cancer cells on the actions of the inhibitors of glycolysis.

Dynamics of intracellular superoxide and NO content in human endotheliocytes and carcinoma cells after treatment with NO synthase inhibitors.

The dynamics of intracellular levels of superoxide and NO after cell treatment with NO synthase inhibitors were studied in human cells expressing various NOS isoforms: endotheliocytes and ECV-304 (eNOS) and carcinoma cells and HeLa-G63 (iNOS). Cytometric analysis of changes in the cell fluorescence intensity was carried out using superoxide and NO fluorescent indicators (dihydroethidene and DAF-2-DA, respectively). Intracellular levels of superoxide decreased in HeLa-G63 and ECV-304 cells after their incubation in medium with aminoguanidine, L-NAME, and D-NAME. Intracellular NO level decreased only in HeLa-G63 cells after incubation in medium with aminoguanidine and L-NAME, but not D-NAME. The level of NO returned to normal after 7-h culturing in inhibitor-free medium, while the level of superoxide increased and remained high throughout 3 generations. Incubation of cells with D-NAME did not increase the intracellular level of superoxide. Presumably, high prolonged generation of superoxide is a delayed result of inhibition of NO synthesis in HeLa-G63 cells.