EFFECT OF PROOXIDANTS ON MITOCHONDRIAL PERMEABILITY TRANSITION AND CELL-DEATH IN EHRLICH ASCITES TUMOR-CELLS

Ca2+ retention in mitochondria, opening of the Cysclosporin A- sensiti ve permeability transition pore and cell death were studied in Ehrlich ascites tumour cells in the presence of different prooxidants. Low co ncentrations (1 - 20 mu M) of the prooxidants (menadione, cumenehydrop eroxide, t-butylhydroperoxide) induced pore-opening in permeabilized c ells at threshold Ca2+ load. Incubation of cells with low concentratio ns of prooxidants was able to induce cell cycle disturbance and cell d eath. Under the prooxidant effect, mitochondrial membrane potential dr op and Ca2+ retention decrease in mitochondria were found to precede d eath of Ehrlich ascites tumour cells.