Fig. 6

HDACi ± HY-PDT differentially modulates chromatin structure in the vicinity of CDKN1A regulatory regions. HT-29 cells were treated 24 h with NaPB (1000 μM) followed by 8 h of activation with hypericin (75 nM). Samples treated with drug-free vehicle solvents (<0.1% DMSO) were used as the reference control (Ct). a Enhancer, b promoter, and c gene body regulatory regions in the CDKN1A gene were analyzed by qPCR coupled to chromatin immunoprecipitation (ChIP) of histone modifications that mark each region element. Threshold cycle (Cq) values of Ct qPCR samples were similar. ChIP data was normalized over input DNA and IgG loading control and presented as the average ± SD of two independent experiments each done in triplicates. Data was analyzed using one-way ANOVA with Tukey post hoc test. All conditions were compared to the reference Ct (*p < 0.05, **p < 0.01, ***p < 0.001), and the combined treatments were compared to HY-PDT alone (ǂp < 0.05, ǂǂ < 0.01, ǂǂǂp < 0.001) and to equal concentrations of HDACis alone (▲p < 0.05, ▲▲p < 0.01, ▲▲▲p < 0.001). H3K27ac histone 3 lysine 27 acetylated, H3K4me1 and H3K4me3 histone 3 lysine 4 mono- and trimethylated, respectively, H3K27me3 histone 3 lysine 27 trimethylated