Dominant-negative Jun N-terminal protein kinase (JNK-1) inhibits metabolicoxidative stress during glucose deprivation in a human breast carcinoma cell line

Signal transduction pathways involved in glucose deprivation-induced oxidat ive stress were investigated in human breast carcinoma cells (MCF-7/ADR). I n MCF-7/ADR, glucose deprivation-induced prolonged activation of c-Jun N-te rminal kinase (JNK1) as well as cytotoxicity and the accumulation of oxidiz ed glutathione. Glucose deprivation also caused significant increases in to tal glutathione, cysteine, gamma-glutamylcysteine, and immunoreactive prote ins corresponding to the catalytic as well as regulatory subunits of gamma- glutamylcysteine synthetase, suggesting that the synthesis of glutathione i ncreased as an adaptive response. Expression of a catalytically inactive do minant negative JNK1 in MCF-7/ADR inhibited glucose deprivation-induced cel l death and the accumulation of oxidized glutathione as well as altered the duration of JNK activation from persistent (>2 h) to transient (30 min). I n addition, stimulation of glutathione synthesis during glucose deprivation was not observed in cells expressing the highest levels of dominant negati ve protein. Finally, a linear dose response suppression of oxidized glutath ione accumulation was noted for clones expressing increasing levels of domi nant negative JNK1 during glucose deprivation. These results show that expr ession of a dominant negative JNK1 protein was capable of suppressing persi stent JNK activation as well as oxidative stress and cytotoxicity caused by glucose deprivation in MCF-7/ADR. These findings support the hypothesis th at JNK signaling pathways may control the expression of proteins contributi ng to cell death mediated by metabolic oxidative stress during glucose depr ivation. Finally, these results support the concept that JNK signaling-indu ced shifts in oxidative metabolism may provide a general mechanism for unde rstanding the diverse biological effects seen during the activation of JNK signaling cascades. (C) 2000 Elsevier Science Inc.