Differences of genome-wide methylation level and methylated genes between nasopharyngeal carcinoma cells in same genetic background but different radiation resistance

AIM: To compare the differences of the genome-wide methylation levels and methylated regions between nasopharyngeal carcinoma (NPC) cells in the same genetic background but different radiation resistance (CNE-2 cells and CNE-2R cells). METHODS: Using the method which was developed by Doctor Zhao Cun-you, based on using methyl-sensitive restriction enzyme to measure the genome-wide methylation levels. In addition, MeDIP-Seq was used to analyze the methylated regions in 6 gene functional elements, including the upstream 2k sequence, 5'UTR, coding sequence, intron, 3'UTR and downstream 2k sequence, between CNE-2 cells and CNE-2R cells. RESULTS: The genome-wide methylation level was approximately 30% lower in CNE-2R cells than that in CNE-2 cells. No obvious difference on the amount of genes and the coverage of the peak in the 6 gene functional elements was observed. However, the methylation pattern of plentiful genes had altered in the gene function elements. CONCLUSION: The genome-wide methylation levels and methylated regions between NPC cells in the same genetic background but different radiation resistance were quite different, indicating that the DNA methylation may be associated with NPC radioresistance.