EHMT1 and EHMT2 inhibition induces fetal hemoglobin expression

Blood. 2015 Oct 15;126(16):1930-9. doi: 10.1182/blood-2015-06-649087. Epub 2015 Aug 28.


Fetal hemoglobin (HbF, α2γ2) induction is a well-validated strategy for sickle cell disease (SCD) treatment. Using a small-molecule screen, we found that UNC0638, a selective inhibitor of EHMT1 and EHMT2 histone methyltransferases, induces γ-globin expression. EHMT1/2 catalyze mono- and dimethylation of lysine 9 on histone 3 (H3K9), raising the possibility that H3K9Me2, a repressive chromatin mark, plays a role in silencing γ-globin expression. In primary human adult erythroid cells, UNC0638 and EHMT1 or EHMT2 short hairpin RNA-mediated knockdown significantly increased γ-globin expression, HbF synthesis, and the percentage of cells expressing HbF. At effective concentrations, UNC0638 did not alter cell morphology, proliferation, or erythroid differentiation of primary human CD34(+) hematopoietic stem and progenitor cells in culture ex vivo. In murine erythroleukemia cells, UNC0638 and Ehmt2 CRISPR/Cas9-mediated knockout both led to a marked increase in expression of embryonic β-globin genes Hbb-εy and Hbb-βh1. In primary human adult erythroblasts, chromatin immunoprecipitation followed by sequencing analysis revealed that UNC0638 treatment leads to genome-wide depletion in H3K9Me2 and a concomitant increase in the activating mark H3K9Ac, which was especially pronounced at the γ-globin gene region. In RNA-sequencing analysis of erythroblasts, γ-globin genes were among the most significantly upregulated genes by UNC0638. Further increase in γ-globin expression in primary human adult erythroid cells was achieved by combining EHMT1/2 inhibition with the histone deacetylase inhibitor entinostat or hypomethylating agent decitabine. Our data provide genetic and pharmacologic evidence that EHMT1 and EHMT2 are epigenetic regulators involved in γ-globin repression and represent a novel therapeutic target for SCD.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anemia, Sickle Cell / drug therapy
  • Anemia, Sickle Cell / metabolism
  • Animals
  • Cell Line, Tumor
  • Epigenesis, Genetic / drug effects*
  • Erythroblasts / cytology
  • Erythroblasts / metabolism*
  • Erythroid Cells / cytology
  • Erythroid Cells / metabolism
  • Female
  • Fetal Hemoglobin / biosynthesis*
  • Histocompatibility Antigens / metabolism
  • Histone-Lysine N-Methyltransferase / antagonists & inhibitors*
  • Histone-Lysine N-Methyltransferase / metabolism
  • Humans
  • Male
  • Mice
  • Quinazolines / pharmacology*


  • Histocompatibility Antigens
  • Quinazolines
  • UNC 0638
  • Fetal Hemoglobin
  • EHMT1 protein, human
  • EHMT2 protein, human
  • G9a protein, mouse
  • GLP protein, mouse
  • Histone-Lysine N-Methyltransferase