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Project description:Pediatric acute megakaryoblastic leukemia (AMKL) is an aggressive blood cancer associated with poor therapeutic response and high mortality. We developed CBFA2T3-GLIS2-driven mouse models of AMKL that recapitulate the phenotypic and transcriptional signatures of the human disease. We show that CBFA2T3-GLIS2 and GLIS2 modulate similar transcriptional networks. Oncogenic RAS cooperates with GLIS2 to trigger AMKL, enhancing the penetrance and decreasing the latency of CBFA2T3-GLIS2-dependent AMKL. We find that the FDA-approved drug pyrvinium pamoate, a GLI protein inhibitor, can be repurposed to impair CBFA2T3-GLIS2 levels and promote AMKL cell death. In addition, consistent with our findings that both CBFA2T3-GLIS2 and GLIS2 alter the expression of numerous BH3-only proteins, murine and patient-derived AMKL cells are sensitive to the BCL-2 inhibitor navitoclax. We observe a striking synergistic response to combined treatment with pyrvinium pamoate and navitoclax, suggesting a novel therapeutic option for pediatric patients suffering from CBFA2T3-GLIS2-driven AMKL.
2023-08-04 | GSE208186 | GEO
Project description:Pediatric acute megakaryoblastic leukemia (AMKL) is an aggressive blood cancer associated with poor therapeutic response and high mortality. We developed CBFA2T3-GLIS2-driven mouse models of AMKL that recapitulate the phenotypic and transcriptional signatures of the human disease. We show that CBFA2T3-GLIS2 and GLIS2 modulate similar transcriptional networks. Oncogenic RAS cooperates with GLIS2 to trigger AMKL, enhancing the penetrance and decreasing the latency of CBFA2T3-GLIS2-dependent AMKL. We find that the FDA-approved drug pyrvinium pamoate, a GLI protein inhibitor, can be repurposed to impair CBFA2T3-GLIS2 levels and promote AMKL cell death. In addition, consistent with our findings that both CBFA2T3-GLIS2 and GLIS2 alter the expression of numerous BH3-only proteins, murine and patient-derived AMKL cells are sensitive to the BCL-2 inhibitor navitoclax. We observe a striking synergistic response to combined treatment with pyrvinium pamoate and navitoclax, suggesting a novel therapeutic option for pediatric patients suffering from CBFA2T3-GLIS2-driven AMKL.
2023-08-04 | GSE208157 | GEO
Project description:Pediatric acute megakaryoblastic leukemia (AMKL) is an aggressive blood cancer associated with poor therapeutic response and high mortality. We developed CBFA2T3-GLIS2-driven mouse models of AMKL that recapitulate the phenotypic and transcriptional signatures of the human disease. We show that CBFA2T3-GLIS2 and GLIS2 modulate similar transcriptional networks. Oncogenic RAS cooperates with GLIS2 to trigger AMKL, enhancing the penetrance and decreasing the latency of CBFA2T3-GLIS2-dependent AMKL. We find that the FDA-approved drug pyrvinium pamoate, a GLI protein inhibitor, can be repurposed to impair CBFA2T3-GLIS2 levels and promote AMKL cell death. In addition, consistent with our findings that both CBFA2T3-GLIS2 and GLIS2 alter the expression of numerous BH3-only proteins, murine and patient-derived AMKL cells are sensitive to the BCL-2 inhibitor navitoclax. We observe a striking synergistic response to combined treatment with pyrvinium pamoate and navitoclax, suggesting a novel therapeutic option for pediatric patients suffering from CBFA2T3-GLIS2-driven AMKL.
2023-08-04 | GSE208158 | GEO
Project description:Acute megakaryoblastic leukemia (AMKL) is a heterogeneous disease generally associated with poor prognosis. Gene expression profiles indicate the existence of distinct molecular subgroups, and several genetic alterations have been characterized in the past years, including the t(1;22)(p13;q13) and the trisomy 21 associated with GATA1 mutations. However, the majority of patients do not present with known mutations, and the limited access to primary patient leukemic cells impedes the efficient development of novel therapeutic strategies. In this study, using a xenotransplantation approach, we have modeled human pediatric AMKL in immunodeficient mice. Analysis of high-throughput RNA sequencing identified recurrent fusion genes defining new molecular subgroups. One subgroup of patients presented with MLL or NUP98 fusion genes leading to up-regulation of the HOX A cluster genes. A novel CBFA2T3-GLIS2 fusion gene resulting from a cryptic inversion of chromosome 16 was identified in another subgroup of 31% of non-Down syndrome AMKL and strongly associated with a gene expression signature of Hedgehog pathway activation. These molecular data provide useful markers for the diagnosis and follow up of patients. Finally, we show that AMKL xenograft models constitute a relevant in vivo preclinical screening platform to validate the efficacy of novel therapies such as Aurora A kinase inhibitors.
| S-EPMC3478932 | biostudies-literature
Project description:ABCG2 encodes a transporter protein that is associated with multidrug-resistant phenotypes in many cancers, including acute myeloid leukemia (AML); high levels of expression are generally associated with a poor prognosis. To better understand how expression of ABCG2 is controlled in pediatric AML, we performed a detailed analysis of the ABCG2 transcript isoforms from a variety of tissue sources, including 85 pediatric AML samples. These studies revealed a complex 5' untranslated region (UTR) with 6 novel exons and multiple splice variants. Samples from children with acute megakaryoblastic leukemia (AML FAB-M7) not associated with Down syndrome showed uniformly higher levels of ABCG2 transcripts than samples from children with other AML subtypes. A novel 5' UTR identified 90kb upstream of the exon 2 translation initiation site was expressed only in M7 AML subtypes. An associated upstream promoter fragment was shown to be selectively expressed in megakaryoblastic leukemia cells but not in human epithelial cell lines. These findings identify a new tissue-specific ABCG2 promoter that is selectively expressed in pediatric M7 AML. We also show a relatively high incidence of ABCG2 mRNA expression in non-Down associated M7 AML, which may contribute to the relatively poor prognosis of the M7 AML subtype.
| S-EPMC3163718 | biostudies-literature
Project description:Activated tyrosine kinases have been frequently implicated in the pathogenesis of cancer, including acute myeloid leukemia (AML), and are validated targets for therapeutic intervention with small-molecule kinase inhibitors. To identify novel activated tyrosine kinases in AML, we used a discovery platform consisting of immunoaffinity profiling coupled to mass spectrometry that identifies large numbers of tyrosine-phosphorylated proteins, including active kinases. This method revealed the presence of an activated colony-stimulating factor 1 receptor (CSF1R) kinase in the acute megakaryoblastic leukemia (AMKL) cell line MKPL-1. Further studies using siRNA and a small-molecule inhibitor showed that CSF1R is essential for the growth and survival of MKPL-1 cells. DNA sequence analysis of cDNA generated by 5'RACE from CSF1R coding sequences identified a novel fusion of the RNA binding motif 6 (RBM6) gene to CSF1R gene generated presumably by a t(3;5)(p21;q33) translocation. Expression of the RBM6-CSF1R fusion protein conferred interleukin-3 (IL-3)-independent growth in BaF3 cells, and induces a myeloid proliferative disease (MPD) with features of megakaryoblastic leukemia in a murine transplant model. These findings identify a novel potential therapeutic target in leukemogenesis, and demonstrate the utility of phosphoproteomic strategies for discovery of tyrosine kinase alleles.
| S-EPMC1896120 | biostudies-literature
Project description:This review aims to provide an overview of the current knowledge of the genetic lesions driving pediatric acute myeloid leukemia (AML), emerging biological concepts, and strategies for therapeutic intervention. Hereby, we focus on lesions that preferentially or exclusively occur in pediatric patients and molecular markers of aggressive disease with often poor outcome including fusion oncogenes that involve epigenetic regulators like KMT2A, NUP98, or CBFA2T3, respectively. Functional studies were able to demonstrate cooperation with signaling mutations leading to constitutive activation of FLT3 or the RAS signal transduction pathways. We discuss the issues faced to faithfully model pediatric acute leukemia in mice. Emerging experimental evidence suggests that the disease phenotype is dependent on the appropriate expression and activity of the driver fusion oncogenes during a particular window of opportunity during fetal development. We also highlight biochemical studies that deciphered some molecular mechanisms of malignant transformation by KMT2A, NUP98, and CBFA2T3 fusions, which, in some instances, allowed the development of small molecules with potent anti-leukemic activities in preclinical models (e.g., inhibitors of the KMT2A-MENIN interaction). Finally, we discuss other potential therapeutic strategies that not only target driver fusion-controlled signals but also interfere with the transformed cell state either by exploiting the primed apoptosis or vulnerable metabolic states or by increasing tumor cell recognition and elimination by the immune system.
| S-EPMC6803505 | biostudies-literature
Project description:Despite recent advances in the treatment of children with acute megakaryoblastic leukemia (AMKL) using intensified treatment protocols, clear prognostic indicators, and treatment recommendations for this acute myeloid leukemia (AML) subgroup are yet to be defined. Here, we report the outcome of 97 pediatric patients with de novo AMKL (excluding Down syndrome [DS]) enrolled in the prospective multicenter studies AML-BFM 98 and AML-BFM 04 (1998-2014). AMKL occurred in 7.4 % of pediatric AML cases, at younger age (median 1.44 years) and with lower white blood cell count (mean 16.5?×?10(9)/L) as compared to other AML subgroups. With 60?±?5 %, children with AMKL had a lower 5-year overall survival (5-year OS; vs. 68?±?1 %, P log rank?=?0.038). Yet, we achieved an improved 5-year OS in AML-BFM 04 compared to AML-BFM 98 (70?±?6 % vs. 45?±?8 %, P log rank?=?0.041). Allogeneic hematopoietic stem cell transplantation in first remission did not provide a significant survival benefit (5-year OS 70?±?11 % vs. 63?±?6 %; P Mantel-Byar?=?0.85). Cytogenetic data were available for n?=?78 patients. AMKL patients with gain of chromosome 21 had a superior 5-year OS (80?±?9 %, P log rank?=?0.034), whereas translocation t(1;22)(p13;q13) was associated with an inferior 5-year event-free survival (38?±?17 %, P log rank?=?0.04). However, multivariate analysis showed that treatment response (bone marrow morphology on day 15 and 28) was the only independent prognostic marker (RR?=?4.39; 95 % CI, 1.97-9.78). Interestingly, GATA1-mutations were detected in six patients (11 %) without previously known trisomy 21. Thus, AMKL (excluding DS) remains an AML subgroup with inferior outcome. Nevertheless, with intensive therapy regimens, a steep increase in the survival rates was achieved.
| S-EPMC4488462 | biostudies-literature
Project description:Acute megakaryoblastic leukemia (AMKL) is a subtype of acute myeloid leukemia (AML) in which cells morphologically resemble abnormal megakaryoblasts. While rare in adults, AMKL accounts for 4-15% of newly diagnosed childhood AML cases. AMKL in individuals without Down syndrome (non-DS-AMKL) is frequently associated with poor clinical outcomes. Previous efforts have identified chimeric oncogenes in a substantial number of non-DS-AMKL cases, including RBM15-MKL1, CBFA2T3-GLIS2, KMT2A gene rearrangements, and NUP98-KDM5A. However, the etiology of 30-40% of cases remains unknown. To better understand the genomic landscape of non-DS-AMKL, we performed RNA and exome sequencing on specimens from 99 patients (75 pediatric and 24 adult). We demonstrate that pediatric non-DS-AMKL is a heterogeneous malignancy that can be divided into seven subgroups with varying outcomes. These subgroups are characterized by chimeric oncogenes with cooperating mutations in epigenetic and kinase signaling genes. Overall, these data shed light on the etiology of AMKL and provide useful information for the tailoring of treatment.
| S-EPMC5687824 | biostudies-literature
Project description:Aberrations in epigenetic modifications contribute to leukemogenesis in childhood acute myeloid leukemia (AML). We combined DNA hypomethylating agent azacitidine with histone deacetylase inhibitor panobinostat in preclinical models of childhood AML. Synergistic cytotoxic effect upon treatment with azacitidine and panobinostat with combination indices <1.0 was observed. Azacitidine and panobinostat increased median survival by 26 and 6days respectively in MV4;11 xenografted mice. Mice treated with both drugs showed a drastic reduction in leukemic burden leading to complete remission sustained for the duration of the experimental period lasting more than 519days. Reduced leukemic burden and prolonged survival was also observed in AML-193 xenografted mice treated with azacitidine-panobinostat combination. Differential gene expression profiling was performed on AML cells treated with azacitidine, panobinostat or azacitidine-panobinostat combination. Functional mapping of transcripts uniquely regulated by the azacitidine-panobinostat combination in MV4;11 cells identified p53 as an upstream regulator. A comparison of the uniquely modulated transcripts by azacitidine-panobinostat combination in MV4;11 cells versus AML-193 and THP-1 cells, bearing mutated p53, also revealed p53 as the topmost upstream regulator. Finally, expression of mutant p53 in MV4;11 cells reduced sensitivity to azacitidine-panobinostat combination, suggesting that p53 may be a predictor of response to epigenetic therapy in pediatric AML.
| S-EPMC5507334 | biostudies-literature