US EPA

8359587 

Journal Article 

Glutathione depletion sensitizes tumor cells to oxidative cytolysis 

Arrick, BA; Nathan, CF; Griffith, OW; Cohn, ZA 

1982 

Yes 

Journal of Biological Chemistry
ISSN: 0021-9258
EISSN: 1083-351X 

257 

3 

1231-1237 

English 

Activated macrophages and granulocytes lyse tumor cells in the presence of phorbol myristate acetate or antitumor antibody via the secretion of reactive oxygen intermediates, such as H2O2. We compared the lysis of GSH-depleted or normal tumor cells by oxidants generated with glucose oxidase or activated macrophages and granulocytes. Two independent methods were employed to deplete cells specifically of GSH: inhibition of GSH biosynthesis with buthionine sulfoximine, a selective inhibitor of γ-glutamylcysteine synthetase, and treatment with 1-chloro-2,4-dinitrobenzene (CDNB), which covalently binds GSH as catalyzed by endogenous GSH S-transferase, Incubation of P388 lymphoma or P815 mastocytoma cells with 0.2 mM buthionine sulfoximine resulted in a 50% reduction in GSH content by 4.5-5 h and >90% depletion by 15 h. Treatment of P815 cells with CDNB for 15 min resulted in a dose-dependent loss of GSH, with a maximal depletion of approximately 70% obtained with 10 μM CDNB. GSH depletion of P815 and P388 markedly enhanced their sensitivity to lysis by a flux of H2O2. Such cells could be lysed by dilutions of glucose oxidase and numbers of phorbol myristate acetate-stimulated granulocytes and activated macrophages which were ineffectual against untreated tumors. Recovery of tumor cell resistance to H2O2 after GSH depletion by either buthionine sulfoximine or CDNB followed the same time course as resynthesis of cellular GSH. These results and the previous finding that inhibition of the GSH redox cycle of tumor cells enhances both macrophage and glucose oxidase mediated cytolysis demonstrate the importance of GSH to tumor cell antioxidant defenses.