Cell-cycle regulator E2F1 and microRNA-223 comprise an autoregulatory negative feedback loop in acute myeloid leukemia.

Transcription factor CCAAT enhancer binding protein alpha (C/EBPalpha) is essential for granulopoiesis and its function is deregulated in leukemia. Inhibition of E2F1, the master regulator of cell-cycle progression, by C/EBPalpha is pivotal for granulopoiesis. Recent studies show microRNA-223 (miR-223), a transcriptional target of C/EBPalpha, as a critical player during granulopoiesis. In this report, we demonstrate that during granulopoiesis microRNA-223 targets E2F1. E2F1 protein was up-regulated in miR-223 null mice. We show that miR-223 blocks cell-cycle progression in myeloid cells. miR-223 is down-regulated in different subtypes of acute myeloid leukemia (AML). We further show that E2F1 binds to the miR-223 promoter in AML blast cells and inhibits miR-223 transcription, suggesting that E2F1 is a transcriptional repressor of the miR-223 gene in AML. Our study supports a molecular network involving miR-223, C/EBPalpha, and E2F1 as major components of the granulocyte differentiation program, which is deregulated in AML.

[1]  N. Rajewsky,et al.  Widespread changes in protein synthesis induced by microRNAs , 2008, Nature.

[2]  Kathryn A. O’Donnell,et al.  c-Myc-regulated microRNAs modulate E2F1 expression , 2005, Nature.

[3]  C. Croce,et al.  MicroRNAs in normal and malignant hematopoiesis , 2008, Current opinion in hematology.

[4]  Marie S. Hasemann,et al.  Loss of C/EBPα cell cycle control increases myeloid progenitor proliferation and transforms the neutrophil granulocyte lineage , 2005, The Journal of experimental medicine.

[5]  G. Behre,et al.  Dominant-negative mutations of CEBPA, encoding CCAAT/enhancer binding protein-alpha (C/EBPalpha), in acute myeloid leukemia. , 2001, Nature genetics.

[6]  F. Lo‐Coco,et al.  Epigenetic silencing of the myelopoiesis regulator microRNA-223 by the AML1/ETO oncoprotein. , 2007, Cancer cell.

[7]  M. Rubin,et al.  Elevated E 2 F 1 Inhibits Transcription of the Androgen Receptor in Metastatic Hormone-Resistant Prostate Cancer , 2006 .

[8]  K. Helin,et al.  E2F1-mediated transcriptional inhibition of the plasminogen activator inhibitor type 1 gene. , 2001, European journal of biochemistry.

[9]  J. Cleveland,et al.  E2F-1 and E2F-3 are functionally distinct in their ability to promote myeloid cell cycle progression and block granulocyte differentiation. , 1998, Cell growth & differentiation : the molecular biology journal of the American Association for Cancer Research.

[10]  Peter F. Johnson,et al.  Molecular stop signs: regulation of cell-cycle arrest by C/EBP transcription factors , 2005, Journal of Cell Science.

[11]  S. McKnight.  McBindall—A Better Name for CCAAT/Enhancer Binding Proteins? , 2001, Cell.

[12]  B. Porse,et al.  E2F Repression by C/EBPα Is Required for Adipogenesis and Granulopoiesis In Vivo , 2001, Cell.

[13]  Heidi Dvinge,et al.  Modeling of C/EBPalpha mutant acute myeloid leukemia reveals a common expression signature of committed myeloid leukemia-initiating cells. , 2008, Cancer cell.

[14]  Alessandro Fatica,et al.  A Minicircuitry Comprised of MicroRNA-223 and Transcription Factors NFI-A and C/EBPα Regulates Human Granulopoiesis , 2005, Cell.

[15]  Yoko Fukuda,et al.  An Evolutionarily Conserved Mechanism for MicroRNA-223 Expression Revealed by MicroRNA Gene Profiling , 2007, Cell.

[16]  David L. Crowe,et al.  E2F-1 represses transcription of the human telomerase reverse transcriptase gene , 2001, Nucleic Acids Res..

[17]  T. Golub,et al.  c-Myc Is a Critical Target for C/EBPα in Granulopoiesis , 2001, Molecular and Cellular Biology.

[18]  P. Farnham,et al.  The identification of E2F1-specific target genes , 2002, Proceedings of the National Academy of Sciences of the United States of America.

[19]  Stephanie Daignault,et al.  Elevated E2F1 inhibits transcription of the androgen receptor in metastatic hormone-resistant prostate cancer. , 2006, Cancer research.

[20]  Eric B Haura,et al.  Direct repression of the Mcl-1 promoter by E2F1 , 2002, Oncogene.

[21]  Pu Zhang,et al.  Enhancement of hematopoietic stem cell repopulating capacity and self-renewal in the absence of the transcription factor C/EBP alpha. , 2004, Immunity.

[22]  Y. Nagamine,et al.  Pocket Protein-Independent Repression of Urokinase-Type Plasminogen Activator and Plasminogen Activator Inhibitor 1 Gene Expression by E2F1 , 2000, Molecular and Cellular Biology.

[23]  C. Nerlov.  C/EBPalpha mutations in acute myeloid leukaemias. , 2004, Nature reviews. Cancer.

[24]  R. Bernards,et al.  Re-Evaluating Cell-Cycle Regulation by E2Fs , 2006, Cell.

[25]  R. Umek,et al.  CCAAT-enhancer binding protein: a component of a differentiation switch. , 1991, Science.

[26]  K. Akashi,et al.  Transgenic targeting with regulatory elements of the human CD34 gene. , 2002, Blood.

[27]  Victor X Jin,et al.  E2F in vivo binding specificity: comparison of consensus versus nonconsensus binding sites. , 2008, Genome research.

[28]  B. Porse,et al.  C/EBPα: A tumour suppressor in multiple tissues? , 2006 .

[29]  T. Kummalue,et al.  Cell cycle inhibition mediated by the outer surface of the C/EBPα basic region is required but not sufficient for granulopoiesis , 2003, Oncogene.

[30]  D. Tenen,et al.  CCAAT/Enhancer Binding Protein α Is a Regulatory Switch Sufficient for Induction of Granulocytic Development from Bipotential Myeloid Progenitors , 1998, Molecular and Cellular Biology.

[31]  C. Conti,et al.  E2F1 Has Both Oncogenic and Tumor-Suppressive Properties in a Transgenic Model , 1999, Molecular and Cellular Biology.

[32]  B. Porse,et al.  C/EBPalpha: a tumour suppressor in multiple tissues? , 2006, Biochimica et biophysica acta.

[33]  M. Caligiuri,et al.  MicroRNA expression in cytogenetically normal acute myeloid leukemia. , 2008, The New England journal of medicine.

[34]  Vincent De Guire,et al.  An E2F/miR-20a Autoregulatory Feedback Loop* , 2007, Journal of Biological Chemistry.

[35]  Daniel G. Tenen,et al.  Transcription factors in myeloid development: balancing differentiation with transformation , 2007, Nature Reviews Immunology.

[36]  O. Kirak,et al.  Regulation of progenitor cell proliferation and granulocyte function by microRNA-223 , 2008, Nature.

[37]  Pu Zhang,et al.  Dominant-negative mutations of CEBPA, encoding CCAAT/enhancer binding protein-α (C/EBPα), in acute myeloid leukemia , 2001, Nature Genetics.

[38]  C. Nerlov.  C/EBPα mutations in acute myeloid leukaemias , 2004, Nature Reviews Cancer.

[39]  D. Iliopoulos,et al.  E2F1-regulated microRNAs impair TGFbeta-dependent cell-cycle arrest and apoptosis in gastric cancer. , 2008, Cancer cell.

[40]  D. Bartel,et al.  The impact of microRNAs on protein output , 2008, Nature.

[41]  D. T. Kurtz,et al.  C/EBPα Inhibits Cell Growth via Direct Repression of E2F-DP-Mediated Transcription , 2000, Molecular and Cellular Biology.

[42]  J. Mendell.  MicroRNAs: Critical Regulators of Development, Cellular Physiology and Malignancy , 2005, Cell cycle.

[43]  D. Tenen,et al.  The amino terminal and E2F interaction domains are critical for C/EBP alpha-mediated induction of granulopoietic development of hematopoietic cells. , 2003, Blood.

[44]  Daniel G Tenen,et al.  ATRA resolves the differentiation block in t(15;17) acute myeloid leukemia by restoring PU.1 expression. , 2004, Blood.