LBH589 induces hyper-acetylation of histones H3 and H4, increases p21, but depletes Bcr-Abl in K562 and p-FLT-3 and FLT-3 in MV4-11 cells. Cells were treated with indicated concentrations of LBH589 for 24 hours. After this, histones were isolated and Western blot analyses of acetylated histones H3 and H4 were performed in K562 cells (A) and MV4-11 cells (C). Ponceau staining served as the loading control. Western blot analyses of p21, Bcr-Abl, p-AKT, AKT, p-STAT5, STAT5, c-Myc, Bcl-x_L, Pim-2, and PARP were performed on the cell lysates from K562 cells (B), and Western blot analyses of p21, p-FLT-3, FLT-3, p-AKT, AKT, p-ERK1/2, ERK1/2, p-STAT5, STAT5, c-Myc, and PARP were performed on the cell lysates from MV4-11 cells (D). The levels of β-actin served as the loading control. LBH589 inhibits DNA binding activity of STAT5 in K562 and MV4-11 cells. Following treatment of K562 (E) or MV4-11 cells (F) with the indicated concentrations of LBH589 for 24 hours, nuclear extracts were tested for the DNA binding activity of STAT5 by EMSA. For supershift analysis, the nuclear extracts were treated with anti-STAT5 antibody before the addition of the poly(dI-dC) and the labeled DNA probe (see “Materials and methods”).