Core binding factor (CBF) leukemias, characterized by translocations t(8;21) or inv(16)/t(16;16) targeting the core binding factor, constitute acute myeloid leukemia (AML) subgroups with favorable prognosis. However, about 40% of patients relapse, and the current classification system does not fully reflect this clinical heterogeneity. Previously, gene expression profiling (GEP) revealed two distinct CBF leukemia subgroups displaying significant outcome differences and identified apoptotic signaling, MAPKinase signaling and chemotherapy-resistance mechanisms among the most significant differentially regulated pathways. We now tested different inhibitors of the respective pathways in a cell line model (six cell lines reflecting the CBF subgroup specific gene expression alterations), and found apoptotic signaling to be differentiating between the CBF subgroup models. In accordance, primary samples from newly diagnosed CBF AML patients (n=23) also showed differential sensitivity to in vitro treatment with a Smac mimetic such as BV6, an antagonist of inhibitor of apoptosis (IAP) proteins , and ABT-737, a BCL2 inhibitor. Furthermore, GEP revealed the BV6 resistant cases to resemble the previously identified unfavorable CBF subgroup. Thus, our current findings show deregulated IAP expression and apoptotic signaling to differentiate clinically relevant CBF subgroups, which were independent of known molecular markers, thereby providing a starting point for novel therapeutic approaches.
Deregulated apoptosis signaling in core-binding factor leukemia differentiates clinically relevant, molecular marker-independent subgroups.
Sex, Age
View SamplesPurpose: In acute myeloid leukemia (AML) without retinoic acid receptor (RAR) rearrangement the effect of all-trans retinoic acid (ATRA) is still poorly understood despite an association of NPM1 mutation and ATRA response. Recently, PRAME (preferentially expressed antigen in melanoma) has been shown to be a dominant repressor of RAR-signaling. Experimental design: Thus, we further investigated ATRA response mechanisms, especially the impact of PRAME expression on ATRA-responsiveness by profiling gene expression in K562 cell lines. Results: Our data revealed a PRAME-expression associated gene pattern to be significantly enriched for genes involved in the retinoic acid metabolic process. In leukemia cell line models we could demonstrate that retinoic acid-regulated cell proliferation and differentiation are impacted by PRAME expression. Conclusions: PRAME seems to impair differentiation and to increase proliferation likely via blocking RAR-signaling, which might be reversed by ATRA.
PRAME-induced inhibition of retinoic acid receptor signaling-mediated differentiation--a possible target for ATRA response in AML without t(15;17).
Treatment
View SamplesGene expression in NPM1 wildtype and mutated AML patients with high or low hsa_circ_0075001 expression
Circular RNAs of the nucleophosmin (NPM1) gene in acute myeloid leukemia.
Specimen part, Disease, Disease stage
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The clathrin-binding domain of CALM and the OM-LZ domain of AF10 are sufficient to induce acute myeloid leukemia in mice.
Specimen part
View SamplesThe t(10;11) p (13;q14) translocation, giving rise to CALM-AF10, is a recurring chromosomal translocation observed in several types of acute leukemias as well as in lymphoma. We have previously demonstrated that the expression of the human CALM/AF10 fusion gene in murine bone marrow stem and progenitor cells results in an aggressive acute myeloid leukemia in vivo. In this study, we have screened the various domains essential for CALM-AF10 function and leukemogenicity. Our study identifies a mutant of CALM-AF10 that greatly enhances the clonogenic potential of hematopoietic progenitors while retaining key characteristics of disease induced by the full length CALM-AF10 fusion.
The clathrin-binding domain of CALM and the OM-LZ domain of AF10 are sufficient to induce acute myeloid leukemia in mice.
Specimen part
View SamplesRecently, the p53-miR-34a network was identified to play an important role in tumorigenesis. As in acute myeloid leukemia with complex karyotype (CK-AML) TP53 alterations are the most common known molecular lesion, we further analyzed the p53-miR-34a axis in CK-AML with known TP53 status. Clinically, low miR-34a expression and TP53 alterations predicted for chemotherapy resistance and inferior outcome. Notably, in TP53unaltered CK-AML high miR-34a expression predicted for inferior overall survival (OS), whereas in TP53biallelic altered CK-AML high miR-34a expression pointed to better OS.
Altered miRNA and gene expression in acute myeloid leukemia with complex karyotype identify networks of prognostic relevance.
Disease
View SamplesAberrant expression of the homeodomain transcription factor CDX2 occurs in most cases of acute myeloid leukemia (AML) and promotes leukemogenesis, making CDX2, in principle, an attractive therapeutic target. Conversely, CDX2 acts as a tumor suppressor in colonic epithelium. The effectors mediating the leukemogenic activity of CDX2 and the mechanism underlying its context-dependent properties are poorly characterized, and strategies for interfering with CDX2 function in AML remain elusive. We report data implicating repression of the transcription factor KLF4 as important for the oncogenic activity of CDX2, and demonstrate that CDX2 differentially regulates KLF4 in AML versus colon cancer cells through a mechanism that involves tissue-specific patterns of promoter binding and epigenetic modifications. Furthermore, we identified deregulation of the PPAR signaling pathway as a feature of AML expressing CDX2, and observed that PPAR agonists derepress KLF4 and are preferentially toxic to CDX2-positive leukemic cells. These data delineate transcriptional programs associated with CDX2 expression in hematopoietic cells; provide insight into the antagonistic duality of CDX2 function in AML versus colon cancer; and suggest reactivation of KLF4 expression, through modulation of PPAR signaling, as a new therapeutic modality in a large proportion of AML patients.
CDX2-driven leukemogenesis involves KLF4 repression and deregulated PPARγ signaling.
No sample metadata fields
View SamplesA previously predictive CEBPA double mutant (CEBPAdm) signature was hampered by the recently reported CEBPA silenced AML cases that carry a similar gene expression profile (GEP). Two independent AML cohorts were used to train and evaluate the predictive value of the CEBPAdm signature in terms of sensitivity and specificity. A predictive signature was created, containing 25-probe sets by using a logistic regression model with Lasso regularization, which selects discriminative probe sets between the classes, CEBPAdm and all other AML cases, CEBPA wild type (CEBPAwt) and CEBPA single mutant (CEBPAsm). Subsequently, a classifier was trained on the entire HOVON-SAKK cohort based on a two-class approach; CEBPAdm versus all other cases (CEBPAwt and CEBPAsm). This trained classifier subsequently classified 16 candidate CEBPAdm cases in the AMLSG-cohort out of 154 AML cases. This approach showed perfect sensitivity and specificity (both 100%). In addition, we have performed a classification between CEBPAdm ,CEBPAsm, and CEBPAwt to infer if we were able to accurately classify CEBPAsm cases. We observed that all CEBPAsm cases were classified as CEBPAwt, thus CEBPAsm cases do not have a consistent gene expression pattern and are different from the CEBPAdm group.
Prognostic impact, concurrent genetic mutations, and gene expression features of AML with CEBPA mutations in a cohort of 1182 cytogenetically normal AML patients: further evidence for CEBPA double mutant AML as a distinctive disease entity.
No sample metadata fields
View SamplesAcute myeloid leukemia (AML) is characterized by molecular heterogeneity. As commonly altered genomic regions point to candidate genes involved in leukemogenesis, we used microarray-based comparative genomic hybridization and single nucleotide polymorphism profiling data of 391 AML cases to further narrow down genomic regions of interest. Targeted-resequencing of 1000 genes located in the critical regions was performed in a representative cohort of 50 AML samples comprising all major cytogenetic subgroups. We identified 120 missense/nonsense mutations as well as 60 insertions/deletions affecting 73 different genes (~3.6 tumor-specific aberrations/AML). While most of the newly identified alterations were non-recurrent, we observed a number of mutations affecting genes involved in epigenetic regulation including known candidates like TET2, TET1, DNMT3A and DNMT1, as well as mutations in the histone methyltransferases NSD1, EZH2 and MLL3. Furthermore, we found mutations in the splicing factor SFPQ and in the non-classical regulators of mRNA-processing CTCF and RAD21. These splicing-related mutations affected 10% of AML patients in a mutually exclusive manner. In conclusion, we could identify a significant enrichment of alterations in genes involved in aberrant splicing and epigenetic regulation in genomic regions commonly altered in AML, highlighting their important role in the molecular pathogenesis of AML.
Commonly altered genomic regions in acute myeloid leukemia are enriched for somatic mutations involved in chromatin remodeling and splicing.
Specimen part, Disease
View SamplesTotal bone marrow (BM) from miR-223 knockout (mir-223-/-) and wildtype (miR-223+/+) mice 21 was extracted, prestimulated for 2 days. Then, the BM cells were simultaneously cotransduced with MSCV-Hoxa9-pgk-neomycin and a MSCV-Meis1-IRES-YFP by co-cultivation with irradiated (4,000 cGy) viral producers. HoxA9-Meis1 transduced cells were sorted for YFP expression and continuously selected with neomycin (1.4 mg/ml).
Comprehensive analysis of mammalian miRNA* species and their role in myeloid cells.
No sample metadata fields
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