Impact of GFRA1 gene reactivation by DNA demethylation on prognosis of patients with metastatic colon cancer

Figure 1 Demethylation and expression status of the GFRA1 gene in human cancer cell lines. A: Chromatograms of methylated and demethylated GFRA1 (mGFRA1 and dmGFRA1) PCR products for 20 cell lines using denaturing high performance liquid chromatography. Blood DNA with and without M.sssI methylation was used as mGFRA1 and dmGFRA1 controls, respectively; B: The results of bisulfate sequencing for four representative cell lines containing only dmGFRA1 alleles or mGFRA1 alleles. Each line represents one clone; each red dot represents one methylated CpG site. The GFRA1 amplicon containing 42 CpG sites is also displayed at the top; C: Comparison of relative GFRA1 mRNA levels in 20 cell lines with different demethylation statuses; D: Dot chart for correlation between the levels of dmGFRA1 and GFRA1 mRNA in these cell lines.