EFFECT OF UKRAIN ON HUMAN LYMPHOMA CELL GROWTH WITH DIFFERENT EXPRESSIONS OF HEAT SHOCK PROTEIN 70 (HSP70)

摘要

The aim of this study was to determine the involvement of heat shock protein 70 (hsp70) in the protective mechanism of U-937 lymphoid cells against Ukrain-induced cell death, We compared the viability and susceptibility of human lymphoid cells U-937 and U-937/hsp70, which differed in their expression of hsp70, to apoptotic stimuli induced by the anticancer drug Ukrain, Ukrain is known to exhibit high cytotoxic and cytosta-tic activity against malignant, but not normal, cells. Ukrain at concentrations of 34,3, 51,4 and 68,5 muM was shown to decrease the growth rate of U-937 cells by about 3-fold compared with untreated cells, and approximately 55%-65% of the cell population died after 24 h incubation with Ukrain at these concentrations, U-937/hsp70 cells were more resistant to the same concentrations of Ukrain, A lower concentration of Ukrain 6.86 muM induced cell death in about 20% of both U-937 and U-937/hsp70 cells compared with control, and the mean living cell concentration in both cell types was found to decrease similarly: by 1.3-fold after 48 h incubation, and by 1,7-fold after 72 h. U-937 and U-937/hsp70 cells both demonstrated susceptibility to apoptosis induced by Ukrain 6.86 /muM, whereas Ukrain at a concentration of 3,43 muM was shown to be nontoxic for U-937 and U-937/hsp70 cells. Treatment of cells with Ukrain at a concentration of 6,86 muM for 4 h was followed by decreased cathepsin B and L activity in both U-937 and U-937/hsp70 cells. The data presented in this paper indicate that hsp70 protected U-937 lymphoid cells from death induced by high concentrations of Ukrain.