Suppression of zinc-induced p53 phosphorylation and p21 expression by wortmannin in A549 human pulmonary epithelial cells

In A549 cells treated with zinc sulfate (ZnSO₄), the levels of p53 phosphorylated at Ser15 and total p53 protein increased. Treatment with wortmannin, an inhibitor of phosphatidylinositol 3-kinase (PI3K)-related kinases, suppressed ZnSO₄-induced phosphorylation and accumulation of p53 protein. Expression of cyclin-dependent kinase inhibitor p21, one of the genes regulated by p53, was up-regulated following exposure to ZnSO₄, and suppressed by preincubation with wortmannin. These results suggest that zinc might induce the phosphorylation of p53 at Ser15 through wortmannin-sensitive pathway(s) at least in part, and result in the transactivation of the p21 gene in this human pulmonary epithelial cell line.