Comparison of various HbF-inducing compounds on HbF synthesis and globin mRNA expression in K562 cells.

Cells were treated with HDAC inhibitors (black bars) and different HbF-inducing compounds (gray bars) by using concentrations with maximum HbF-inducing activity or solvent only (white bars) for 4 days. HbF per total protein (A) and cell numbers (B) were expressed relative to untreated control cells. (C) HbF per total Hb. Each experiment was performed 4 times, and standard errors were calculated as indicated. Co indicates untreated control cells; But, 0.6 mM butyrate; PA, 2 mM phenylacetate; Iso, 2 mM isobutyramide; Hu, 100 μM hydroxyurea; 5-aC, 5 μM 5-aza-cytidine; and Val, 2 mM valproate. (D) Analysis of globin mRNA expression in untreated (−) and apicidin-treated (+) K562 cells by quantitative real-time RT-PCR. mRNA expression of untreated and apicidin-treated cells was quantified by real-time RT-PCR, values were normalized by β-actin mRNA, and data expressed relative to untreated control cells. Experiments were repeated 3 times and standard errors were calculated.