Pediatric Acute Myeloid Leukemia (AML) is an aggressive and poor prognosis malignancy for which there are few effective targeted approaches, despite the numerous genetic alterations, including MLL gene rearrangements (MLL-r). The histone methyltransferase DOT1L is involved in supporting proliferation of MLL-r cells, for which a target inhibitor, Pinometostat, has been evaluated in a clinical trial recruiting pediatric MLL-r leukemic patients. However, modest clinical effects have been reported. Recent studies reported that additional leukemia subtypes lacking MLL-r are sensitive to DOT1L inhibition. Here we report that targeting DOT1L with Pinometostat sensitizes pediatric AML cells to further treatment with the multi-kinase inhibitor Sorafenib, irrespectively of MLL-r. DOT1L pharmacologic inhibition induces AML cell differentiation and modulated expression of genes with relevant roles in cancer development. Such modifications in transcriptional program impact on further treatments, inducing a strong sensitization to Sorafenib, with increased apoptosis and growth suppression of both AML cell lines and primary pediatric AML cells with diverse genotypes. We used microarrays to define differential regulation of gene expression in AML cell lines with or without MLL gene rearrangements following pharmacologic inhibition of DOT1L.
Inhibition of Methyltransferase DOT1L Sensitizes to Sorafenib Treatment AML Cells Irrespective of <i>MLL</i>-Rearrangements: A Novel Therapeutic Strategy for Pediatric AML.
Treatment
View SamplesThe cellular origin and molecular progression towards aggressive cancers such as acute myeloid leukemia (AML) remain elusive. Clinically, Myelodysplastic syndromes (MDS) and related myeloproliferative neoplasias (MPN) disorders1-5 are believed to present as a precursor stage to lethal AML development. Despite the identification of cytogenetic abnormalities and increased activation of signaling in human MDS/MPN, specific pathways that either sustain or initiate disease progression and evolve into self-sustaining leukemic-initiating cells (L-ICs)13 have not been elucidated. Here we demonstrate that tissue specific loss of glycogen synthase kinase-3 (GSK3 beta) initiates the emergence of stable Pre-leukemic-ICs (PLIC) in vivo. In contrast to deletion or transgenic perturbation of pathways associated with AML eg. -catenin/Wnt, serial transplantation of PL-IC produced abnormal hematological disease that phenotypically and molecularly resembles human MDS/MPN. PL-ICs were exclusively generated from GSK3 beta deficient hematopoietic stem cells (HSCs), indicating that disease initiation events collaborate with existing HSC self-renewal machinery. In the absence of GSK3 beta, subsequent deletion of GSK3 beta caused rapid induction of L-ICs that give rise to lethal AML. As these processes were solely driven by dose-dependent deficiencies in GSK3 beta levels, our results suggest that perturbation of this pathway can sufficiently drive and recapitulate a step-wise progression of disease from HSCs to MDS/MPN and subsequent AML. Our study provides a molecular and cellular foundation to understand AML evolution from pre-leukemic precursors. We suggest that defining the molecular states of pre-neoplastic disease will allow patient stratification at early stages of MDS/MPN onset and aid in the development of therapeutic targeting of causal pathways responsible for the earliest stages of leukemic initiation events.
GSK3 Deficiencies in Hematopoietic Stem Cells Initiate Pre-neoplastic State that Is Predictive of Clinical Outcomes of Human Acute Leukemia.
Sex, Specimen part
View SamplesIncreased CREB levels and upregulation of its target genes expression resulted in increased myelopoiesis and colony formation.
MicroRNA-34b promoter hypermethylation induces CREB overexpression and contributes to myeloid transformation.
Specimen part, Disease, Disease stage, Subject
View SamplesWe retrospectively analyzed AML patients enrolled in the AIEOP since 2000, 42 patients with 11q23 rearrangement were analyzed by gene expression profile
MLL partner genes drive distinct gene expression profiles and genomic alterations in pediatric acute myeloid leukemia: an AIEOP study.
Disease, Disease stage
View SamplesWe examined if the minimal residual disease (MRD) and the Allelic Ratio (AR) of FLT3 internal tandem duplication (ITD) mutated patients may be prognostic factors. We correlated these parameters both with event free survival (EFS), with incidence of relapse and with gene expression profile (GEP). GEP showed that patients with high-ITD-AR or persistent MRD had different expression profiles. Results indicated that the ITD-AR levels and the MRD after I induction course are associated with transcriptional oncogenic profiles, which highlight differences in epigenetic control that may explain the variability in outcome among FLT3-ITD patients
Characterization of children with FLT3-ITD acute myeloid leukemia: a report from the AIEOP AML-2002 study group.
Specimen part, Disease
View SamplesJuvenile myelomonocytic leukemia (JMML) is a very rare and aggressive stem cell disease that mainly occurs in young children. RAS activation constitutes the core component of oncogenic signaling. In addition, the leukemic blasts of a quarter of JMML patients present with monosomy 7 (-7), whereas more than half of the patients show enhanced age-adjusted fetal hemoglobin (HbF) levels. Hematopoietic stem cell transplantation is the current standard of care. This results in an event-free survival of 50 - 60%, indicating that novel molecular driven therapeutic options are urgently needed. Using gene expression profiling in an extensive series of 82 patient samples, we aimed at understanding the molecular biology behind JMML and identified a previously unrecognized molecular subgroup characterized by high LIN28B expression.
LIN28B overexpression defines a novel fetal-like subgroup of juvenile myelomonocytic leukemia.
Disease
View SamplesPulmonary alveoli are complex architectural units thought to undergo endogenous or pharmacologically induced programs of regeneration and degeneration. To study the molecular mechanism of alveoli loss mice were calorie restricted at different timepoints. Lungs were harvested and processed for RNA extraction.
Calorie-related rapid onset of alveolar loss, regeneration, and changes in mouse lung gene expression.
Time
View SamplesIt has been shown that dexamethasone (Dex) impairs the normal lung septation that occurs in the early postnatal period. Treatment with retinoic acid (ATRA) abrogates the effects of Dex. To understand the molecular basis for the Dex indiced inhibition of the formation of the alveoli and the ability of ATRA to prevent the inhibition of septation, gene expression was analyzed in 4-day old mice treated with diluent (control), Dex-treated and ATRA+Dex-treated.
DNA microarray analysis of neonatal mouse lung connects regulation of KDR with dexamethasone-induced inhibition of alveolar formation.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Molecular heterogeneity in acute renal allograft rejection identified by DNA microarray profiling.
No sample metadata fields
View Samples-catenin signaling is required for hair follicle development, but it is unknown whether it is sufficient to activate expression of hair follicle genes in embryonic skin. To address this we profiled gene expression in dermis from E15.5 KRT14-Cre Ctnnb1(Ex3)fl/+ embryos carrying an activating mutation in epithelial beta-catenin, and control littermate embryos.
Molecular heterogeneity in acute renal allograft rejection identified by DNA microarray profiling.
No sample metadata fields
View Samples