title: Decitabine maintains hematopoietic precursor self-renewal by preventing repression of stem cell genes by a differentiation-inducing stimulus.
abstract: The cytosine analogue decitabine alters hematopoietic differentiation. For example, decitabine treatment increases self-renewal of normal hematopoietic stem cells. The mechanisms underlying decitabine-induced shifts in differentiation are poorly understood, but likely relate to the ability of decitabine to deplete the chromatin-modifying enzyme DNA methyltransferase 1 (DNMT1), which plays a central role in transcription repression. HOXB4 is a transcription factor that promotes hematopoietic stem cell self-renewal. In hematopoietic precursors induced to differentiate by the lineage-specifying transcription factor Pu.1 or by the cytokine granulocyte-colony stimulating factor, there is rapid repression of HOXB4 and other stem cell genes. Depletion of DNMT1 using shRNA or decitabine prevents HOXB4 repression by Pu.1 or granulocyte-colony stimulating factor and maintains hematopoietic precursor self-renewal. In contrast, depletion of DNMT1 by decitabine 6 hours after the differentiation stimulus, that is, after repression of HOXB4 has occurred, augments differentiation. Therefore, DNMT1 is required for the early repression of stem cell genes, which occurs in response to a differentiation stimulus, providing a mechanistic explanation for the observation that decitabine can maintain or increase hematopoietic stem cell self-renewal in the presence of a differentiation stimulus. Using decitabine to deplete DNMT1 after this early repression phase does not impair progressive differentiation.
authors.affiliation: Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA.
authors.forename: Zhenbo
authors.initials: Z
authors.lastname: Hu
authors.forename: Soledad
authors.initials: S
authors.lastname: Negrotto
authors.forename: Xiaorong
authors.initials: X
authors.lastname: Gu
authors.forename: Reda
authors.initials: R
authors.lastname: Mahfouz
authors.forename: Kwok Peng
authors.initials: KP
authors.lastname: Ng
authors.forename: Quteba
authors.initials: Q
authors.lastname: Ebrahem
authors.forename: Edward
authors.initials: E
authors.lastname: Copelan
authors.forename: Harinder
authors.initials: H
authors.lastname: Singh
authors.forename: Jaroslaw P
authors.initials: JP
authors.lastname: Maciejewski
authors.forename: Yogen
authors.initials: Y
authors.lastname: Saunthararajah
mesh_terms: D000818:Animals; D001374:Azacitidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics*; D019070:Cell Lineage / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism; D000077209:Decitabine; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics*; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology*; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000201:enzymology / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000378:metabolism; D006801:Humans; D051379:Mice; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism*; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism; D000099232:Proto-Oncogene Protein Spi-1
chemical_list: D001374:Azacitidine; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; D000077209:Decitabine; D016179:Granulocyte Colony-Stimulating Factor; D018398:Homeodomain Proteins; D011518:Proto-Oncogene Proteins; D034741:RNA, Small Interfering; D012097:Repressor Proteins; D015534:Trans-Activators; D000099232:Proto-Oncogene Protein Spi-1; C000619380:DNMT1 protein, human; C000619381:Dnmt1 protein, mouse