Role of NF-κB in acid-induced methylation of p16 gene promoter in BAR-T cells. A: knockdown of P50 significantly decreased acid-induced increase in p16 promoter methylation in BAR-T cells, indicating that NF-κB may mediate acid-induced increase in p16 promoter methylation in BAR-T cells. B: knockdown of P50 reversed acid-induced decrease in p16 mRNA level in BAR-T cells, indicating that NF-κB may participate in acid-induced decrease in p16 mRNA in BAR-T cells. C: knockdown of DNMT1 significantly decreased p16 promoter hypermethylation induced by overexpression of p65, a subunit of NF-κB, indicating that P65-induced p16 promoter methylation may depend on activation of DNMT1 (n = 3). ANOVA: *P < 0.05, compared with control siRNA group; **P < 0.05, compared with control siRNA + acid group or control siRNA + p65 group.