p16 epimutation modulates the tumor microenvironment and promotes malignancy of Apc-mutant colon cancer

We previously generated a mouse model of p16 epimutation (named as p16cis/cis) through targeted knock-in of a 140-bp Alu-related DNA sequence (cis-element) that facilitates the spread of DNA methylation at promoter CpG islands (CGIs) in cis (Yu et al. JCI, 2014). We generated primary mouse embryonic fibroblasts (MEFs) from p16cis/cis and control mice. By whole genome bisulfite sequencing (WGBS) for comprehensive DNA methylation profiling, we showed that cis-element-mediated approach specifically induces p16 promoter hypermethylation. Genome-wide DNA methylation profiling by WGBS was performed in primary ctr-MEF at passage 7 and cis-MEF at passage 12