Induction of c-jun protooncogene expression by hydrogen peroxide through hydroxyl radical generation and p60 SRC tyrosine kinase activation

The mechanisms of signal transduction of c-jun induction by hydrogen peroxide are elucidated in NIH3T3 cells by using trapping agents of hydroxyl free radical or inhibitors of various protein kinases. Pre-treatment of the cell with hydroxyl radical scavenger dimethyl sulfoxide (DMSO) abolishes the H 2 O 2 -induced c-jun expression. Hydroxyl radical generation can be detected and quantified in cells treated sequentially with DMSO and H 2 O 2 for 30 min respectively by methane sulfinic acid (MSA) production, especially that from particulate fraction. Induction of c-jun by H 2 O 2 is also dramatically reduced by pretreating the cells with biological antioxidant vit. E. Protein tyrosine kinase activity of membrane fraction is induced by H 2 O 2 within 5 to 10 min, which can be prevented by DMSO pretreatment. Inhibitor of non-receptor type tyrosine kinase, herbimycin A, has inhibitory effect on H 2 O 2 -induced c-jun expression while the inhibitor of receptor type tyrosine kinase, tyrphostin 23 or inhibitor of cyclic AMP dependent protein kinase, KT 5720, has not. TPA pre-treatment that depletes protein kinase C (PKC) has no influence on the c-jun induction by H 2 O 2. Our results suggest that the highly reactive species HO • is generated after H 2 O 2 enter cells and mediate the signal responses of H 2 O 2 including c-jun induction and the activation of p60 src tyrosine kinase might be one of the molecular events associated with the c-jun induction pathway.