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Transcriptomic and epigenetic analyses of mouse organoids expressing BrafV600E mutation [Exome-seq]

ABSTRACT: Abnormal promoter DNA hypermethylation arises early during tumorigenesis and yet its role in cancer initiation has remained underexplored. An important scenario for examining this is, BRAFV600E-mutant colon adenocarcinomas (COAD) which most often arise in the proximal colon and harbor extensive, abnormal gene promoter CpG-island methylation or the methylator phenotype (CIMP). How CIMP and BRAF-mutations specifically interact for COAD initiation has remained unclear. Using mouse colon-derived organoids, we show promoter hypermethylation spontaneously arises in wild type cells mimicking “aging like” phenotype. The silenced genes sufficiently activate the Wnt pathway, causing a stem–like state and profound differentiation block. This phenotype renders long-term cultured organoids to be rapidly susceptible to transformation by BRAFV600E with features of typical right-sided COAD. Our studies tightly link epigenetic abnormalities, suggested to arise with aging, to intestinal cell fate changes and define an “epi-driver” role for multiple abnormally silenced genes that predispose to BRAFV600E-driven colon tumorigenesis.

ORGANISM(S): Mus musculus

PROVIDER: GSE121672 | GEO | 2019/01/01

REPOSITORIES: GEO

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