Suppression of c-Jun/AP-1 activation by an inhibitor of tumor promotion in mouse fibroblast cells.

Curcumin, a dietary pigment responsible for the yellow color of curry, is a potent inhibitor of tumor promotion by phorbol esters. Functional activation of transcriptional factor c-Jun/AP-1 is believed to play an important role in signal transduction of phorbol 12-myristate 13-acetate-induced tumor promotion. Suppression of the c-Jun/AP-1 activation by curcumin is observed in mouse fibroblast cells. In vitro experiments indicate that inhibition of c-Jun/AP-1 binding to its cognate motif by curcumin may be responsible for the inhibition of c-Jun/AP-1-mediated gene expression. These findings show that the effect of curcumin on phorbol 12-myristate 13-acetate-induced inflammation/tumor promotion could be studied at the molecular level.