DNA Hypermethylation Encroachment at CpG Island Borders in Cancer Is Predisposed by H3K4 Monomethylation Patterns
Menée à partir de l'analyse de l'ADN de cellules normales et de cellules cancéreuses, cette étude met en évidence une relation entre le modèle de méthylation H3K4me1 des dinucléotides CpG du promoteur des cellules normales et les caractéristiques de l'hyperméthylation de ce même promoteur après la cancérisation des cellules
Promoter CpG islands are typically unmethylated in normal cells, but in cancer a proportion are subject to hypermethylation. Using methylome sequencing we identified CpG islands that display partial methylation encroachment across the 5′ or 3′ CpG island borders. CpG island methylation encroachment is widespread in prostate and breast cancer and commonly associates with gene suppression. We show that the pattern of H3K4me1 at CpG island borders in normal cells predicts the different modes of cancer CpG island hypermethylation. Notably, genetic manipulation of Kmt2d results in concordant alterations in H3K4me1 levels and CpG island border DNA methylation encroachment. Our findings suggest a role for H3K4me1 in the demarcation of CpG island methylation borders in normal cells, which become eroded in cancer.
Cancer Cell , résumé, 2018