Effect of methylation inhibitor on demethylation pattern of the PD-1 gene in promoter region and PD-1 expression in human T lymphocyte cell line

To observe the demethylation effect of demethylation inhibitor 5-azacytidine (5-Zac) on programmed death receptor 1 (PD-1) in Molt-4 cells (T lymphocyte cell line) and to investigate the relationship between DNA demethylation and expression of PD-1. Molt-4 cells were cultured in the medium containing different concentrations of 5-Zac(0, 5, 10 μmol/L) for 72 h. According to the concentrations of 5-Zac, the Molt-4 cells were divided into a 0 μmol/L 5-Zac group, a 5 μmol/L 5-Zac group, and a 10 μmol/L 5-Zac group. The expression of PD-1 in Molt-4 cells was detected by flow cytometry and the apoptosis rate was calculated. The mRNA transcription level of PD-1 was detected by real-time polymerase chain reaction; Molt-4 cell DNA in all groups were treated by sodium bisulfite. The PD-1 promoter fragment was amplified by PCR, the amplification fragments were transformed into E. coli., the positive clones were selected for equencing, and the methylation status of the fragments of PD-1 promoter was examined. RESULTS Sev