Fig. 2

Quercetin treatment decreases DNMTs, in STAT3-dependent manner, increases global acetylation of H3 and H4, and increases the enrichment of acetylated histone H3 and H4 to the promoters of genes related to the apoptosis pathway. a HL60 and U937 cell lines were treated with 50 μmol/L Qu for 48 h. Western blotting was performed for DNMT1, DNMT3a, p-STAT3, and STAT3 proteins. Values are means ± SD of three independent assays. *p < 0.05 when compared to cell lines treated with vehicle only. One experiment in three is shown. b The mRNA values are expressed as mean ± SD of three independent experiments. *p < 0.05; ** p < 0.005 when compared to HL60 or U937 cells treated with vehicle only. c Confocal microscopy view of HL60 and U937 cells treated with 50 μmol/L Qu for 48 h, incubated with STAT3 antibody and probed with Alexa Fluor 555 (red)-labeled secondary antibody showing a decreased STAT3 expression after treatment. DAPI was used to stain nuclei. d Western blotting analysis of acid extracted proteins of HL60 cell line exposed to 50 μmol/l Qu for 48 h. Qu treatment increases acetylated levels of H3 and H4. One representative experiment in three is shown. e Treatment of HL60 cells with 50 μmol/L Qu for 48 h. Apoptosis ChIP human PCR array for association of acetylated histone H3 and H4 with the promoters of DAPK1, BCL2L11, APAF1, BAX, BNIP3, and BNIP3L was performed; details are provided in the “Methods” section. f Chromatin immunoprecipitation assay was performed for association of acetylated H3 and H4 histones with the promoters of DAPK1 and BCL2L11 in U937 cells treated with 50 μmol/L Qu for 48 h. Qu treatment caused increased association of acetylated histones H3 and H4 to the promoters of DAPK1 and BCL2L11. g BCL2L11, BAX, APAF1, BNIP3, and BNIP3L mRNA expression levels of HL60 and U937 cells treated with 50 μmol/L Qu for 48 h. The mRNA values are expressed as mean ± SD of three independent experiments. *p < 0.05, **p < 0.005, when compared to HL60 or U937 cells + vehicle