GLUTATHIONE CONSUMPTION AND GLUTATHIONE-PEROXIDASE INACTIVATION IN FIBROBLAST CELL-LINES BY 4-HYDROXY-2-NONENAL

Treatment of cultured fibroblasts, designated HA1 cells, with 4-hydrox y-2-nonenal (4HNE) in doses up to 50 nmol/10(6) cells for 3 h results in dose-dependent cytotoxicity measured by clonogenic cell survival wi th 50% cytotoxicity achieved at 32 nmol 4HNE/10(6) cells. 4HNE treatme nt also resulted in dose-dependent reduction of cellular glutathione ( GSH) content and loss of glutathione peroxidase (GPx) activity at 4HNE doses greater than 15 nmol/10(6) cells. By comparison, a 95% oxygen-r esistant variant of HA I cells, designated O2R95 cells, and a hydrogen peroxide-resistant variant of HA1 cells, designated OC14 cells, were found resistant to 4HNE cytotoxicity requiring 54 nmol 4HNE/10(6) cell s and 75 nmol 4HNE/10(6) cells, respectively, for 50% cytotoxicity. In O2R95 cells, dose-dependent decreases were seen in GSH levels and GPx activity. In OC14 cells, however, any reduction in cellular GSH level s required doses of 4HNE greater than 30 nmol/10(6) cells, and GPx act ivity remained unchanged. No changes were seen in glutathione-S-transf erase activity in any of the cell lines at any dose tested. These data indicate a correlation between glutathione modification, in a manner that prevents its recycling, the ability to inactivate enzymes with ac tive site selenocysteine residues and the cytotoxicity of alpha,beta-u nsaturated aldehydes such as 4HNE.