Involvement of the tyrosine phosphorylation pathway in induction of human heme oxygenase-1 by hemin, sodium arsenite, and cadmium chloride.

Abstract

The effect of a tyrosine kinase inhibitor, herbimycin A, on the induction of heme oxygenase-1 (HO-1) mRNA in HeLa cells upon exposure to hemin, sodium arsenite and cadmium chloride was examined. The induction of HO-1 mRNA by hemin was inhibited when the cells were pretreated with herbimycin A. Herbimycin also inhibited arsenite- and cadmium-dependent induction of HO-1 mRNA in a dose-dependent manner, but less inhibition was observed in cadmium-treated cells than in ones treated with hemin- or arsenite. Genistein (50 microM), another tyrosine kinase inhibitor, also inhibited the induction of HO-1 mRNA by hemin, arsenite, and cadmium. Nuclear runoff assays revealed that herbimycin blocked the hemin-induced transcription of the HO-1 gene. The induction of HO-1 mRNA by hemin in human peripheral blood mononuclear cells was inhibited by herbimycin. The tyrosine phosphorylation of a protein with a molecular mass of 66 kDa in the cells was increased by hemin- or arsenite-treatment, and this increase was inhibited by treatment with 5 microM herbimycin. When HeLa cells were treated with a specific inhibitor of the mitogen-activated protein kinase (MAPK)/extracellular-signal regulated kinase cascade, PD58059 (100 microM), suppression of the cadmium-dependent HO-1 induction was not observed, but the hemin- or arsenite-dependent induction was slightly inhibited. SB203580, an inhibitor of p38 MAPK, did not affect the HO-1 induction. These results indicated that signal transduction involving tyrosine kinase rather than the MAPK family regulates the induction of human HO-1 gene expression by stress inducers.