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. 2009 Nov 16;101(3):609–615. doi: 10.1111/j.1349-7006.2009.01439.x

Figure 3.

Figure 3

 Synergistic effect of valproic acid (VPA) and hydroxyurea (HU) on NKG2D ligand (NKG2DL) expression by OUN‐1 chronic myelogenous leukemia cells. (a) OUN‐1 cells and primary leukemic cells from five patients with acute myeloid leukemia were treated with VPA, HU, or VPA + HU for either 24 h (OUN‐1) or 48 h (primary leukemic cells). Each column represents the difference in the mean fluorescence intensity (MFI) level calculated by subtracting the MFI level of untreated cells from that of the cells treated with the indicated condition. Leukemic cells from Patients 3–5 were only examined for the inducibility of MICA/B and ULBP2 by VPA or HU alone. (b) Representative histograms of OUN‐1 and Patient 1’s leukemic cells treated with VPA and HU. Green lines, untreated cells; green lines, cells treated with VPA + HU; purple lines, isotype control; red lines, VPA treated cells. (c) Effect of caffeine on the expression of NKG2DLs induced by VPA + HU. OUN‐1 cells were pretreated with 5 mM caffeine then incubated with either HU or VPA + HU for 24 h. (d) Effect of VPA and HU on the expression of MICA/B and ULBP2 genes. The gene expression levels relative to GAPDH were determined using real‐time PCR. Each column and error bar represents the mean ± SD of the ratios of the NKG2DL mRNA level to the GAPDH mRNA level from three independent experiments. *P < 0.01.