Genetic analysis of Ikaros target genes and tumor suppressor function in BCR-ABL1+ pre-B ALL
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE90670 | GEO | 2017/02/06
SECONDARY ACCESSION(S): PRJNA355305
REPOSITORIES: GEO
Similar Datasets
Project description:Inactivation of the tumor suppressor gene encoding the transcriptional regulator Ikaros (IKZF1) is a hallmark of BCR-ABL1+ precursor B cell acute lymphoblastic leukemia (pre-B ALL). However, the mechanisms by which Ikaros functions as a tumor suppressor in pre-B ALL remain poorly understood. Here, we analyzed a mouse model of BCR-ABL1+ pre-B ALL together with a new model of inducible expression of wild-type Ikaros in IKZF1 mutant human BCR-ABL1+ pre-B ALL. We performed integrated genome-wide chromatin and expression analyses and identified Ikaros target genes in mouse and human BCR-ABL1+ pre-B ALL, revealing novel conserved gene pathways associated with Ikaros tumor suppressor function. Notably, genetic depletion of different Ikaros targets, including CTNND1 and the early hematopoietic cell surface marker CD34, resulted in reduced leukemic growth. Our results suggest that Ikaros mediates tumor suppressor function by enforcing proper developmental stage-specific expression of multiple genes through chromatin compaction at its target genes.
| S-EPMC5339667 | biostudies-literature
Project description:Using patient-derived Ph+ pre-B ALL cells that harbor deletions of the IKZF1 DNA binding domain (Ik6), we performed ATAC-sequencing in cells that inducibly express wild-type Ikaros (Ik1) or an empty vector control.
2017-02-06 | GSE90666 | GEO
Project description:RNA-seq was performed in human Ph+ pre-B ALL cells that harbor a deletion of the Ikaros DNA binding domain (Ik6) after doxycycline induction of exogenous expression of wild-type Ikaros (Ik1) or control empty vector over 0, 12, 24 and 48 hours. Biological replicates (n=2) using independent cultures and inductions were performed.
2017-02-06 | GSE90659 | GEO
Project description:ChIP-seq was performed in patient-derived BCR-ABL1+ (Ph+) pre-B ALL cells that harbor heterozygote deletions of the IKZF1 DNA binding domain (Ik6), using cells that inducibly express wild-type Ikaros (Ik1) or an empty vector control.
2017-02-06 | GSE90656 | GEO
Project description:Genetic analysis of Ikaros target genes and tumor suppressor function in BCR-ABL1+ pre-B ALL
| PRJNA355305 | ENA
Project description:Regulation of oncogenic gene expression by transcription factors that function as tumor suppressors is one of the major mechanisms that regulate leukemogenesis. Understanding this complex process is essential for explaining the pathogenesis of leukemia as well as developing targeted therapies. Here, we provide an overview of the role of Ikaros tumor suppressor and its role in regulation of gene transcription in acute leukemia. Ikaros (IKZF1) is a DNA-binding protein that functions as a master regulator of hematopoiesis and the immune system, as well as a tumor suppressor in acute lymphoblastic leukemia (ALL). Genetic alteration or functional inactivation of Ikaros results in the development of high-risk leukemia. Ikaros binds to the specific consensus binding motif at upstream regulatory elements of its target genes, recruits chromatin-remodeling complexes and activates or represses transcription via chromatin remodeling. Over the last twenty years, a large number of Ikaros target genes have been identified, and the role of Ikaros in the regulation of their expression provided insight into the mechanisms of Ikaros tumor suppressor function in leukemia. Here we summarize the role of Ikaros in the regulation of the expression of the genes whose function is critical for cellular proliferation, development, and progression of acute lymphoblastic leukemia.
| S-EPMC7073093 | biostudies-literature
Project description:The Ikaros transcription factor is crucial for many aspects of hematopoiesis. Loss of function mutations in IKZF1, the gene encoding Ikaros, have been implicated in adult and pediatric B cell acute lymphoblastic leukemia (B-ALL). These mutations result in haploinsufficiency of the Ikaros gene in approximately half of the cases. The remaining cases contain more severe or compound mutations that lead to the generation of dominant-negative proteins or complete loss of function. All IKZF1 mutations are associated with a poor prognosis. Here we review the current genetic, clinical and mechanistic evidence for the role of Ikaros as a tumor suppressor in B-ALL.
| S-EPMC3555193 | biostudies-literature
Project description:To examine Ikaros tumor suppressor mechanisms, we have utilized inducible RNAi to dynamically restore endogenous Ikaros expression in BCR-ABL1+ B-ALL driven by its knockdown (Ikaros knockdown), and compared these tumors to tumors driven by BCR-ABL1 alone (control). Restoration of Ikaros causes rapid regression of tumor cells in vivo, significantly prolonging tumor transplant recipient survival. Using both transgenic and retroviral approaches, we conducted expression analysis of B-ALL by RNA-Seq and have identified a series of Ikaros-regulated genes within established tumor cell in vivo. Comparison of Ikaros-activated and Ikaros-repressed genes with human B-ALL expression data shows a set of conserved Ikaros target genes, some of which are associated with patient outcome (namely, CTNND1, IFITM3 and EMP1).
2016-12-11 | GSE75976 | GEO
Project description:Deletions within the human IKZF1 gene, which encodes Ikaros, a zinc finger transcription factor critical for lymphopoiesis, appear to be the most prominent recurring lesion in human BCR-ABL1+ (Ph+) B-ALL. Furthermore, IKZF1 mutations correlate with poor prognosis of progenitor B-ALL, further strengthening the notion that IKZF1 is a critical tumor suppressor gene in human B-lineage malignancies. To better understand the relationship between Ikzf1 mutations, BCR-ABL, and B-lineage leukemia, we examined the effect of two newly generated Ikzf1 germline mutation on BCR-ABL-induced proliferation and leukemogenesis in vitro and in vivo. We recently showed that deletion of either the exon encoding the first or the fourth DNA-binding zinc finger of Ikaros (IkZnF1-/- and IkZnF4-/-) led to distinct defects in lymphoid development and tumor suppression with de-regulation of distinct subsets of genes, providing a powerful tool for elucidation of Ikaros target genes and mechanism of function. Importantly, IkZnF4-/- had lost Ikaros tumor suppression function, while not abolishing B-cell development. Retroviral expression of BCR-ABL1 p185 in bone marrow cells from the two Ikzf1 mutant strains demonstrated that loss of ZnF4 resulted in expansion of progenitor B cells, with enhanced proliferation in vitro and a less mature cell surface B-cell phenotype in comparison to transduced wild-type bone marrow. Furthermore, in an in vivo model of BCR-ABL+ B-ALL, leukemias generated in the IkZnF4-/- background were more aggressive than those observed in a wild-type background, with cell phenotype corresponding to the in vitro cell cultures. Genome wide high throughput expression analysis (RNA-Seq) revealed a distinct subset of deregulated genes in the IkZnF4-/- BCR-ABL+ in vitro cell cultures, and molecular analysis demonstrated that this in vitro system is amendable for functional studies. These results establish a mouse model for studying the role of Ikzf1 mutations in B-ALL, and for understanding how BCR-ABL collaborates with Ikzf1 mutations to generate aggressive B-ALL.
2017-02-06 | GSE39160 | GEO
Project description:Resistance to tyrosine kinase inhibitors (TKIs) remains a clinical challenge in Ph-positive variants of chronic myeloid leukemia. We provide mechanistic insights into a previously undisclosed MEK1/2/BCR::ABL1/BCR/ABL1-driven signaling loop that may determine the efficacy of arsenic trioxide (ATO) in TKI-resistant leukemic patients. We find that activated MEK1/2 assemble into a pentameric complex with BCR::ABL1, BCR and ABL1 to induce phosphorylation of BCR and BCR::ABL1 at Tyr360 and Tyr177, and ABL1, at Thr735 and Tyr412 residues thus provoking loss of BCR's tumor-suppression functions, enhanced oncogenic activity of BCR::ABL1, cytoplasmic retention of ABL1 and consequently drug resistance. Coherently, pharmacological blockade of MEK1/2 induces dissociation of the pentameric MEK1/2/BCR::ABL1/BCR/ABL1 complex and causes a concurrent BCRY360/Y177, BCR::ABL1Y360/Y177 and cytoplasmic ABL1Y412/T735 dephosphorylation thereby provoking the rescue of the BCR's anti-oncogenic activities, nuclear accumulation of ABL1 with tumor-suppressive functions and consequently, growth inhibition of the leukemic cells and an ATO sensitization via BCR-MYC and ABL1-p73 signaling axes activation. Additionally, the allosteric activation of nuclear ABL1 was consistently found to enhance the anti-leukemic effects of the MEK1/2 inhibitor Mirdametinib, which when combined with ATO, significantly prolonged the survival of mice bearing BCR::ABL1-T315I-induced leukemia. These findings highlight the therapeutic potential of MEK1/2-inhibitors/ATO combination for the treatment of TKI-resistant leukemia.
| S-EPMC10400427 | biostudies-literature