Effect of chrysin on histone modifications and STAT-1 at p21 promoter. (A) Schematic diagram of the human p21
WAF1 promoter illustrating regulatory factor binding sites like −119 (BRCA1), -692 (STAT-1/3/5), -1203 ( RAR), -1394 and −2285 (P53RE), -4232 and −2557 are the (STAT1/3/5) binding sites.The arrow indicates transcriptional start site at +1. (B) Four different regions (−194/-84, -421/-137, -742/-488, -2894/-1753) were amplified by quantitative real time PCR after chromatin immunoprecipitation to observe the region that is highly sensitive to the treatment with chrysin in A375 cells using anti-H3acK14, H4acK12, H3me2K9 and STAT1 antibodies. untr: untreated cells, tr: treated cells.Table below the diagram shows relative location of the four primer pairs used in ChIP assay. (C) Effect of chrysin on the expression of p21 associated STAT proteins in Chrysin and TSA treated A375 cells (i.e STAT-1, STAT-3 and STAT-5a). (D) Graphical representation of STAT protein expression that is associated with p21 in chrysin (40 μM) and TSA (4 μM) treated cells for 24 h time period. *** represents P < 0.001. (E) A375 cells were treated with Chrysin (40 μM) and TSA (4 μM) for 24 h and mRNA was isolated and checked for STAT-1 expression. *** indicates p < 0.001, ** indicates P < 0.01.