Alterations of histone modifications in the KRT13 promoter in OSCC cells. (A) Schematic of the promoter region of the KRT13 gene. The arrow represents the transcription start site, and arrowheads indicate the primer set used for quantitative PCR. The methylation patterns of histone H3 (H3K4me3 and H3K27me3) in the KRT13 promoter in the three OSCC cell lines and HaCaT cells were examined by chromatin immunoprecipitation (ChIP) assay. Fold enrichment of histone H3 modifications was normalized to total histone H3 and calculated relative to that of HaCaT cells. The value of H3K4me3 in the HaCaT cells was set to 1. The means ± SEM for each group (n = 3–5) are shown. Statistical analysis was performed using Student’s t-test. *p < 0.05, **p < 0.01. (B) The levels of PRC2 proteins (Ezh2 and Suz12) were analyzed in the three OSCC cell lines and HaCaT cells by western blotting. Representative images are shown. Fold change in Ezh2 and Suz12 proteins were normalized to β-actin and calculated relative to band intensity of the HaCaT cells. The means ± SEM for each group (n = 3) are shown. Statistical analysis was performed by a one-way analysis of variance followed by Dunnett’s post hoc test. N.S. (not significant).