Fig. 2.

Effect of X-ray irradiation on Dab2 methylation and mRNA level in lung cancer cells with hypermethylation or hypomethylation of the Dab2 gene promoter. a Dab2 gene promoter contains a CpG island with 353 bp nucleotides and 23 CpG dinucleotides (highlighted with gray), transcription start site is highlighted with italics and underlined. b The AMF of non-irradiated lung cancer cells, X-ray irradiated LK and SPC cells are presented in the left, middle and right columns, respectively. LK and SPC cells were defined as hypermethylated or hypomethylated (47.83% VS 10.14%) according to the AMF. X-ray irradiation significantly induced de-methylation in LK and SPC cells compared with non-irradiated cells (black circle represents methylated CG dinucleotides, white circle represents unmethylated CG dinucleotides). c Real-time PCR showed that the Dab2 mRNA level was significantly up-regulated with irradiation of LK cells compared with non-irradiated LK cells (P < 0.05), but a slightly decreased level of Dab2 mRNA was observed in SPC cells with X-ray irradiation. * P < 0.05