Figure 1

X-ray induced over-expression of the Axin gene in lung cancer cell lines with hypermethylated Axin gene. A and B show the methylation status of the promoter and first intron of the Axin gene and levels of Axin transcripts in 4 lung cancer cell lines. Note low Axin mRNA expression (A) in H157 and H446 cells, which exhibit a hypermethylated Axin gene (B). Real-time PCR shows no up-regulation of Axin mRNA in LTE cells and H460 cells (C and F) but a marked increase in the Axin transcripts in H157 (D) and H446 (E) cell lines after X-ray treatment. Note time and dose dependent increase in Axin transcripts after the treatment in both H157 (D) and H446 (E) cell lines. Pro-M, amplification for the methylated Axin gene promoter; Pro-U, amplification for the unmethylated Axin gene promoter; Int1-M, amplification for the methylated first intron of the Axin gene; Int1-U, amplification for the unmethylated first intron of the Axin gene. * P<0.05, and ** P<0.01, in comparison with the group without X-ray irradiation.