DNA methylation patterns separate senescence from malignant transformation potential in human cells [methylation]

ABSTRACT: Replicative senescent cells reportedly share similar DNA methylation changes with cancer cells, which are purported to facilitate tumorigenesis in cells bypassing senescence. However, we now report biologically critical and distinct patterns of DNA methylation evolution between replicative and oncogene-induced senescence and transformation in a classic human cell transformation model. While overall DNA methylation losses and gains occur in both replicative senescent and transformed cells, the patterns evolve more programmatically for the former and stochastically for the latter. Oncogene-induced senescence is an acute process involving minimal changes to DNA methylation. The stochastic DNA methylation alterations in transformation mainly involve a set of pro-survival promoter CpG-island methylation events targeting genes controlling development and differentiation processes, while the senescence-specific promoter changes occur in genes involved in positive regulation of cellular biosynthesis and macromolecular metabolism. The above set of pro-survival promoter CpG-island hypermethylation events, but not the senescence-specific events, are prone to occur in primary tumors and aging tissues. Importantly, cells manifest senescence-specific epigenomic patterns very early during commitment to senescence, and while these “near-senescent” cells can be immortalized, they are refractory to transformation by H-Ras oncoprotein (H-rasV12). The senescence-specific methylation is retained during immortalization and transformation attempts, suggesting it does not function to promote tumorigenesis. Thus, abnormalities in cancer-related methylation has their origins in aging and not replicative senescence, and senescence-associated methylation potentially prevents malignant transformation.

ORGANISM(S): Homo sapiens

PROVIDER: GSE91069 | GEO | 2018/01/31

REPOSITORIES: GEO