FIGURE 4.

The Class I-selective KDACis apicidin and VPA have very similar effects on GR-activated gene expression. Hepa-1c1c7 cells were treated with VPA (5 mm) or apicidin (0.25 μg/ml) for 5 h and Dex for 4 h. In the combination treatments, the KDACis were added 1 h prior to Dex with continued treatment for 4 h. RNA was isolated and subjected to RT-qPCR. A, the distinct chemical structures of VPA and apicidin. B, effects of apicidin on GR target genes found to have impaired transactivation in the presence of VPA. C, effects of apicidin on GR target genes at which transactivation was unaffected by VPA. The graphs shown are the summary of three to five independent experiments and represent -fold changes relative to untreated cells. Asterisks indicate a significant change in -fold induction under the combination treatments relative to Dex alone as determined using the paired t test. *, p ≤ 0.05; **, p ≤ 0.01. Error bars represent S.E.