title: ETS2 and ERG promote megakaryopoiesis and synergize with alterations in GATA-1 to immortalize hematopoietic progenitor cells.
abstract: ETS2 and ERG are transcription factors, encoded on human chromosome 21 (Hsa21), that have been implicated in human cancer. People with Down syndrome (DS), who are trisomic for Hsa21, are predisposed to acute megakaryoblastic leukemia (AMKL). DS-AMKL blasts harbor a mutation in GATA1, which leads to loss of full-length protein but expression of the GATA-1s isoform. To assess the consequences of ETS protein misexpression on megakaryopoiesis, we expressed ETS2, ERG, and the related protein FLI-1 in wild-type and Gata1 mutant murine fetal liver progenitors. These studies revealed that ETS2, ERG, and FLI-1 facilitated the expansion of megakaryocytes from wild-type, Gata1-knockdown, and Gata1s knockin progenitors, but none of the genes could overcome the differentiation block characteristic of the Gata1-knockdown megakaryocytes. Although overexpression of ETS proteins increased the proportion of CD41(+) cells generated from Gata1s-knockin progenitors, their expression led to a significant reduction in the more mature CD42 fraction. Serial replating assays revealed that overexpression of ERG or FLI-1 immortalized Gata1-knockdown and Gata1s knockin, but not wild-type, fetal liver progenitors. Immortalization was accompanied by activation of the JAK/STAT pathway, commonly seen in megakaryocytic malignancies. These findings provide evidence for synergy between alterations in GATA-1 and overexpression of ETS proteins in aberrant megakaryopoiesis.
authors.affiliation: Division of Hematology/Oncology, Northwestern University, Chicago, IL 60611, USA.
authors.forename: Monika J
authors.initials: MJ
authors.lastname: Stankiewicz
authors.forename: John D
authors.initials: JD
authors.lastname: Crispino
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D002478:Cells, Cultured; D004622:Embryo, Mammalian; D005333:Fetus / Q000378:metabolism / Q000502:physiology; D050982:GATA1 Transcription Factor / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D006412:Hematopoietic Stem Cells / Q000378:metabolism / Q000473:pathology* / Q000502:physiology; D008099:Liver / Q000196:embryology / Q000378:metabolism / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D015513:Oncogene Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D050787:Proto-Oncogene Protein c-ets-2 / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D034061:Thrombopoiesis / Q000235:genetics* / Q000502:physiology; D014157:Transcription Factors; D000071230:Transcriptional Regulator ERG
chemical_list: C531115:ERG protein, mouse; C494070:Ets2 protein, mouse; D050982:GATA1 Transcription Factor; C494689:Gata1 protein, mouse; D015513:Oncogene Proteins; D050787:Proto-Oncogene Protein c-ets-2; D014157:Transcription Factors; D000071230:Transcriptional Regulator ERG