A high-throughput screen of inactive X chromosome reactivation identifies the enhancement of DNA demethylation by 5-aza-2′-dC upon inhibition of ribonucleotide reductase. Issue 1 (December 2015)

• Record Type: Journal Article
• Authors: Minkovsky, Alissa; Sahakyan, Anna; Bonora, Giancarlo; Damoiseaux, Robert; Dimitrova, Elizabeth; Rubbi, Liudmilla; Pellegrini, Matteo; Radu, Caius; Plath, Kathrin
• Is Part Of: Epigenetics & chromatin. Volume 8:Issue 1(2015)
• Page Start: 1
• Page End: 17
• Publication Date: 2015-12
• Subjects: X chromosome inactivation -- DNA methylation -- 5-aza-2′-dC -- Ribonucleotide reductase -- Hydroxyurea; Epigenesis -- Periodicals; Chromatin -- Periodicals; 572.8
• DOI: 10.1186/s13072-015-0034-4
• Languages: English
• ISSNs: 1756-8935

Abstract

Abstract Background DNA methylation is important for the maintenance of the silent state of genes on the inactive X chromosome (Xi). Here, we screened for siRNAs and chemicals that reactivate an Xi-linked reporter in the presence of 5-aza-2′-deoxycytidine (5-aza-2′-dC), an inhibitor of DNA methyltransferase 1, at a concentration that, on its own, is not sufficient for Xi-reactivation. Results We found that inhibition of ribonucleotide reductase (RNR) induced expression of the reporter. RNR inhibition potentiated the effect of 5-aza-2′-dC by enhancing its DNA incorporation, thereby decreasing DNA methylation levels genome-wide. Since both 5-aza-2′-dC and RNR-inhibitors are used in the treatment of hematological malignancies, we treated myeloid leukemia cell lines with 5-aza-2′-dC and the RNR-inhibitor hydroxyurea, and observed synergistic inhibition of cell growth and a decrease in genome-wide DNA methylation. Conclusions Taken together, our study identifies a drug combination that enhances DNA demethylation by altering nucleotide metabolism. This demonstrates that Xi-reactivation assays can be used to optimize the epigenetic activity of drug combinations.