Compared with HL-60, HL-60/LR cells lack HDAC6 expression and LAQ824 induces acetylation of histones H3 and H4 in both HL-60 as well as HL-60/LR cells. (A) After treatment of HL-60 and HL-60/LR cells with the indicated concentrations of LAQ824 for 24 hours, histones were isolated and immunoblot analyses of acetylated histones H3 and H4 were performed. Ponceau staining was used to compare equal protein loading in each lane. (B) Total cell lysates from HL-60 and HL-60/LR cells were used to perform Western blot analyses with specific antibodies against HDAC1, HDAC2, HDAC3, HDAC4, HDAC6, HDAC10, and acetylated α-tubulin. The levels of β-actin served as the loading control. (C) Total RNA from HL-60 and HL-60/LR cells was analyzed by reverse-transcription (RT)–PCR using HDAC6 and β-actin primers. (D) HL-60 and HL-60/LR were fixed on slides, stained with FITC-conjugated anti-HDAC6 antibody (green) and/or DAPI (blue), and imaged with a Zeiss LSM510 confocal microscope with a 63×/1.2 NA water-immersion objective lens. (E) HL-60 and HL-60/LR cells were treated with decitabine and/or LAQ824 as indicated. Then, immunoblot analyses were done for p15 and HDAC6 on the total cell lysates. The levels of β-actin in the lysates served as the loading control.