Forced expression of the Ikaros 6 isoform in human placental blood CD34+ cells impairs their ability to differentiate toward the B-lymphoid lineage

Tonnelle, Cécile; Bardin, Florence; Maroc, Christine; Imbert, Anne-Marie; Campa, Fanny; Dalloul, Ali; Schmitt, C.; Chabannon, Christian

doi:10.1182/blood.v98.9.2673

Cited by 47 publications

(39 citation statements)

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“…35,46,47 The role of Ikaros in diseases has only been described for hematologic malignancies, mostly leukemias and lymphomas. The search for Ikaros deregulation in other diseases of the stem cell and erythroid compartments may provide additional information in the future.…”

Section: Discussionmentioning

confidence: 99%

“…35 The Flag sequence was inserted in 5Ј of Ik6 cDNA, upstream of the initiation codon. In a first step, mutation of ATG for ATC, inserting a ClaI site, was introduced by PCR with primers Ik ClaI start and Ik XhoI stop (Table S1, available on the Blood website; see the Supplemental Materials link at the top of the online article).…”

Section: Lentiviral Vectorsmentioning

confidence: 99%

“…34 In this work, we studied the role of Ikaros in human erythropoiesis from CB, and its role in globin switch in adult cells. Using a similar strategy as in a previous study, 35 we inhibited Ikaros function by overexpression of the DN Ik6 isoform throughout in vitro erythroid differentiation from CB or apheresis CD34 ϩ progenitor cells. …”

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confidence: 99%

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The role of Ikaros in human erythroid differentiation

Dijon

Bardin

Murati

et al. 2008

Blood

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Ikaros-a factor that positively or negatively controls gene transcription-is active in murine adult erythroid cells, and involved in fetal to adult globin switching. Mice with Ikaros mutations have defects in erythropoiesis and anemia. In this paper, we have studied the role of Ikaros in human erythroid development for the first time. Using a gene-transfer strategy, we expressed Ikaros 6 (Ik6)-a known dominant-negative protein that interferes with normal Ikaros activity-in cord blood or apheresis CD34 ؉ cells that were induced to differentiate along the erythroid pathway. Lentivirally induced Ik6-forced expression resulted in increased cell death, decreased cell proliferation, and decreased expression of erythroid-specific genes, including GATA1 and fetal and adult globins. In contrast, we observed the maintenance of a residual myeloid population that can be detected in this culture system, with a relative increase of myeloid gene expression, including PU1. IntroductionThe transcription factor Ikaros (also known as LyF-1) was first described to interact with Cd3␦ and TdT promoters in murine thymocyte cells. 1,2 Its sequence is highly conserved between mice and humans, [3][4][5] and its expression is high in the developing and adult hematopoietic systems. 1,6 Ikaros proteins are characterized by the presence of 2 Krüppel-like zinc finger domains. The N-terminal domain is involved in DNA binding, 2,7 while the C-terminal domain is required for homo-or heterodimerization with family members and is composed of 2 zinc fingers. 8 The Ikaros gene contains 7 translated exons and encodes 9 isoforms by means of alternative splicing that alters expression of exons 3 to 6. 2,7 In these different proteins, the number of N-terminal zinc fingers varies from 0 to 4; this combination determines DNA binding affinity. At least 3 zinc fingers in this domain are necessary to efficiently bind to DNA. Ik1, Ik2, Ik3, and IKX are considered as functional isoforms. However, Ik4 can only bind DNA on palindromic sequences. 7 Ik5, Ik6, Ik7, and Ik8 are considered dominantnegative (DN) isoforms because of their capacity to bind other isoforms and their inefficiency to bind DNA. 8 Gene-targeting studies evidenced the fundamental role of Ikaros in hematopoiesis, in particular in T and B lymphocytes, natural killer (NK) and dendritic cells, and stem cells. [9][10][11][12] In addition, analysis of Ikaros L/L mice (insertion of the ␤-Gal gene in exon-2 of the Ikaros gene) revealed that Ikaros is expressed at low levels in a majority of Ter-119 ϩ erythroid cells. 10 Other studies of Ikaros DN (deletion of exon 7) and null (deletion of dimerization domain) mice show that Ikaros is important for erythroid differentiation. 13 These mice display a decrease of erythroid precursor numbers, and a drop in hematocrit levels 2 to 3 weeks after birth. In MEL (murine erythroleukemia) cells, Ikaros is associated with the chromatin remodelling PYR complex which binds to an intergenic domain between the ␥-globin and ␤-globin genes, and facilitates the switch be...

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Section: Discussionmentioning

confidence: 99%

Section: Lentiviral Vectorsmentioning

confidence: 99%

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The role of Ikaros in human erythroid differentiation

Dijon

Bardin

Murati

et al. 2008

Blood

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“…In a previous study, Tonnelle et al found that CD341 progenitor cells transduced with Ik6 show a decrease in the percentage of CD10 and CD19 expressing cells compared to controls when cocultured with the MS-5 murine cell line. 18 Here, we clearly show a large reduction in the number of B2201 cells generated when progenitor cells are transduced with Ik6. However, we do not see a reduction in the proportion of B2201 cells in the Ik6-transplanted animals compared to controls.…”

Section: Discussionmentioning

confidence: 60%

“…9,13 Forced expression of Ik6 in human cord blood CD341 cells can impair B cell differentiation. 18 Since Ik6 overexpression is found in many leukaemias, it is possible that Ik6 per se may have an oncogenic action. To examine this hypothesis, we decided to test the effect of Ik6 overexpression in murine haematopoietic progenitor cells using colony formation assays.…”

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confidence: 99%

The Ikaros splice isoform, Ikaros 6, immortalizes murine haematopoietic progenitor cells

Ruiz

Williams

Brady

2008

Intl Journal of Cancer

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Alternative pre-mRNA splicing is emerging as a major control point in both the initiation and progression of tumourigenesis. Overexpression of the dominant negative Ikaros splice isoform, Ik6, is found in many human cancers particularly leukaemias. Ik6 has been demonstrated to have a role in cell survival in both myeloid-and lymphoid cytokine-dependent cell lines. To investigate the oncogenic potential of Ik6, we retrovirally transduced murine haematopoietic progenitor cells with Ik6 and have analysed the effects on proliferation and differentiation of these precursors using myeloid and lymphoid in vitro colony formation assays. We found that Ik6 can immortalize haematopoietic progenitor cells in myeloid conditions. Using an in vivo transplantation assay, we found that Ik6 favours reconstitution by haematopoietic precursors. These findings suggest that Ik6 may play an important role in the generation of the leukaemic phenotype.

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The Biology of Adult Acute Lymphoblastic Leukemia

Radich

Sala²

2010

Adult Acute Lymphocytic Leukemia

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Forced expression of the Ikaros 6 isoform in human placental blood CD34+ cells impairs their ability to differentiate toward the B-lymphoid lineage

Cited by 47 publications

References 41 publications

The role of Ikaros in human erythroid differentiation

The role of Ikaros in human erythroid differentiation

The Ikaros splice isoform, Ikaros 6, immortalizes murine haematopoietic progenitor cells

The Biology of Adult Acute Lymphoblastic Leukemia

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