mRNA expression and DNA methylation analysis of the inhibitory mechanism of HO on the proliferation of A549 cells.

Reactive oxygen species, particularly hydrogen peroxide (HO), can induce proliferation inhibition and death of A549 cells via oxidative stress. Oxidative stress has effect on DNA methylation. Oxidative stress and DNA methylation feature a common denominator: The one carbon cycle. To explore the inhibitory mechanism of HO on the proliferation of lung cancer cells, the present study analysed the mRNA expression and methylation profiles in A549 cells treated with HO for 24 h, as adenocarcinoma is the most common pathological type of lung cancer. The DNA methylation profile was constructed using reduced representation bisulphite sequencing, which identified 29,755 differentially methylated sites (15,365 upregulated and 14,390 downregulated), and 1,575 differentially methylated regions located in the gene promoters were identified using the methylKit. Analysis of the assocaition between gene expression and methylation levels revealed that several genes were downregulated and hypermethylated, including cyclin-dependent kinase inhibitor 3, denticleless E3 ubiquitin protein ligase homolog, centromere protein (CENP)F, kinesin family member (KIF)20A, CENPA, KIF11, PCNA clamp-associated factor and GINS complex subunit 2, which may be involved in the inhibitory process of HO on the proliferation of A549 cells.