title: EVI1 abrogates interferon-alpha response by selectively blocking PML induction.
abstract: EVI1 is an oncogene frequently associated with chronic and acute myeloid leukemia. In hematopoietic cells, EVI1 impairs several pathways including proliferation, differentiation, and apoptosis. Interferon-alpha (IFN-alpha) is a powerful cytokine that controls the immune response and limits the expansion of several tissues including bone marrow. These properties contribute to the effectiveness of IFN-alpha in the treatment of many neoplastic disorders especially chronic myeloid leukemia. We report here that in murine hematopoietic progenitors the expression of EVI1 completely abrogates the antiproliferative and apoptotic effects of IFN-alpha. EVI1 does not repress the JAK/STAT signaling pathway or the activation of many IFN-responsive genes. On the contrary, EVI1 prolongs the phosphorylation of STAT1 and the activation of an IFN-dependent reporter gene. However, EVI1 specifically represses the IFN-dependent induction of the tumor suppressor PML and blocks the apoptotic pathways activated by PML. We show that the position of the ISRE, which is located within the first exon of PML, is critical to block PML induction by IFN-alpha. The relocation of the ISRE to a position upstream of the transcription start site is sufficient to re-establish the response to IFN in the presence of EVI1. Our data suggest that stabilized STAT1 phosphorylation and prolonged binding of the STAT1 complex to the first exon could impair PML transcription and inhibit the activation of PML-dependent apoptotic pathways resulting in loss of IFN response. These results point to a novel mechanism utilized by an oncogene to escape normal cell response to growth-controlling cytokines.
authors.affiliation: Department of Pathology and Cancer Center, University of Illinois, Chicago, Illinois 60607, USA.
authors.forename: Silvia
authors.initials: S
authors.lastname: Buonamici
authors.forename: Donglan
authors.initials: D
authors.lastname: Li
authors.forename: Fady M
authors.initials: FM
authors.lastname: Mikhail
authors.forename: Antonella
authors.initials: A
authors.lastname: Sassano
authors.forename: Leonidas C
authors.initials: LC
authors.lastname: Platanias
authors.forename: Oscar
authors.initials: O
authors.lastname: Colamonici
authors.forename: John
authors.initials: J
authors.lastname: Anastasi
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Nucifora
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D006801:Humans; D016898:Interferon-alpha / Q000378:metabolism*; D000074008:MDS1 and EVI1 Complex Locus Protein; D051379:Mice; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D000071156:Promyelocytic Leukemia Protein; D011519:Proto-Oncogenes / Q000235:genetics; D050794:STAT1 Transcription Factor; D015398:Signal Transduction / Q000235:genetics; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D025521:Tumor Suppressor Proteins
chemical_list: D004268:DNA-Binding Proteins; D016898:Interferon-alpha; D000074008:MDS1 and EVI1 Complex Locus Protein; C063575:MECOM protein, human; C499305:Mecom protein, mouse; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; C513293:Pml protein, mouse; D000071156:Promyelocytic Leukemia Protein; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; C494080:Stat1 protein, mouse; D015534:Trans-Activators; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; C070576:PML protein, human