PD-L1 Expression in Human Breast Cancer Stem Cells Is Epigenetically Regulated through Posttranslational Histone Modifications

Figure 4

A schematic diagram summarizing the epigenetic events involved in the regulation of PD-L1 expression in MCF-7 and BT-549 cell lines and tumorspheres. The PD-L1 promoter CpG is hypomethylated in tumorspheres. Moreover, distribution of repressive histones (H3K27me3 and H3K9me3) in the PD-L1 promoter is decreased along with an upregulation of histone acetylation enzymes in tumorspheres, compared with cell lines.