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bioRxiv · 10.1101/2021.09.12.459949

The DNMT1 inhibitor GSK-3484862 mediates global demethylation in murine embryonic stem cells

Portilho, N. A.·Saini, D.·Hossain, I.·Sirois, J.·Moraes, C.·Pastor, W. A.
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Abstract

BackgroundDNA methylation plays an important role in regulating gene expression in mammals. The covalent DNMT1 inhibitors 5-azacytidine and decitabine are widely used in research to reduce DNA methylation levels, but they impart severe cytotoxicity which limits their demethylation capability and confounds interpretation of experiments. Recently, a non-covalent inhibitor of DNMT1 called GSK-3484862 was developed by GlaxoSmithKline. We sought to determine whether GSK-3484862 can induce demethylation more effectively than 5-azanucleosides. Murine embryonic stem cells (mESC) are an ideal cell type in which to conduct such experiments, as they have a high degree of DNA methylation but tolerate dramatic methylation loss. ResultsWe determined the cytotoxicity and optimal concentration of GSK-3484862 by treating wild-type (WT) or Dnmt1/3a/3b triple knockout (TKO) mESC with different concentrations of the compound, which was obtained from two commercial sources. Concentrations of 10 {micro}M or below were readily tolerated for 14 days of culture. Known DNA methylation targets such as germline genes and GLN-family transposons were upregulated within two days of the start of GSK-3484862 treatment. By contrast, 5-azacytidine and decitabine induced weaker upregulation of methylated genes and extensive cell death. Whole genome bisulfite sequencing (WGBS) showed that treatment with GSK-3484862 induced dramatic DNA methylation loss, with global CpG methylation levels falling from near 70% in WT mESC to less than 18% after 6 days of treatment with GSK-3484862, similar to the methylation level observed in Dnmt1 deficient mESCs. ConclusionsGSK-3484862 mediates striking demethylation in mESCs with minimal non-specific toxicity.

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Portilho, N. A., Saini, D., Hossain, I., Sirois, J., Moraes, C., Pastor, W. A.. 2021-09-12. The DNMT1 inhibitor GSK-3484862 mediates global demethylation in murine embryonic stem cells. https://doi.org/10.1101/2021.09.12.459949

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