Fig. 4.

Inhibitors of the H3K4 demethylase, KDM5B, upregulated HEXIM1 expression. MDA-MB-231 cells were treated with indicated concentrations of 4a1 and KDOAM25 a for 5 h for RT-PCR analyses of HEXIM1 mRNA relative to GAPDH mRNA or b for 10 h for western blot analyses of HEXIM1 protein expression relative to GAPDH; c MDA-MB-468 cells were treated with 4a1 (100 μM), KDOAM25 (500 nM), or KDOAM32 (500 nM); d cells were processed for Western blot analyses of HEXIM1, KDM5B, or GAPDH protein expression. KDOAM32 is an inactive structurally related analog. Figures are representative of at least three experiments. For a and b, *P < 0.01 relative to DMSO-treated cells based on t test