Effects of violacein on MAPKs phosphorylation and on p21, STAT1, and STAT2 expression in HL60. Cells were treated with violacein (100 and 1000 nM), and the phosphorylation of MAPKs (A); c-jun and CREB (B); and p21, STAT1, and STAT2 expression (C) were evaluated by immunoblotting. Soluble lysates were matched for protein content and analyzed on Western blot. The phosphorylation of p38 was also analyzed in human lymphocytes (L). One representative immunoblot of 3 independent experiments is presented.