T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic cancer frequently associated with activating mutations in NOTCH1. Early studies identified NOTCH1 as an attractive therapeutic target for the treatment of T-ALL through the use of gamma-secretase inhibitors (GSIs). Here, we characterized the interaction between PF-03084014, a clinically-relevant GSI, and dexamethasone in preclinical models of glucocorticoid-resistant T-ALL. Combination treatment of the GSI PF-03084014 with glucocorticoids induced a synergistic antileukemic effect in human T-ALL cell lines and primary human T-ALL patient samples. Molecular characterization of the response to PF-03084014 plus glucocorticoids through gene expression profiling revealed transcriptional upregulation of the glucocorticoid receptor as the mechanism mediating the enhanced glucocorticoid response. Moreover, treatment with PF-03084014 and glucocorticoids in combination was highly efficacious in vivo, with enhanced reduction of tumor burden in a xenograft model of T-ALL. Finally, glucocorticoid treatment was highly effective at reversing PF-03084014-induced gastrointestinal toxicity via inhibition of goblet cell metaplasia. These results suggest that combination of PF-03084014 treatment with glucocorticoids may be well-tolerated and highly active for the treatment of glucorticoid-resistant T-ALL.
Preclinical analysis of the γ-secretase inhibitor PF-03084014 in combination with glucocorticoids in T-cell acute lymphoblastic leukemia.
Cell line, Treatment
View SamplesTo formally address the tumor suppressor activity of Sh2b3 in vivo, we tested the interaction between oncogenic NOTCH1 and Sh2b3 loss in a retroviral- transduction bone marrow transplantation model of NOTCH-induced T-ALL
Genetic loss of SH2B3 in acute lymphoblastic leukemia.
Specimen part
View SamplesEarly immature T-cell acute lymphoblastic leukemias (T-ALLs) account for about 5-10% of pediatric T-ALLs and are associated with poor prognosis. However, the genetic defects that drive the biology of these tumors remain largely unknown. Analysis of microarray gene expression signatures in adult T-ALL demonstrated a high prevalence of early immature leukemias and revealed a close relationship between these tumors and myeloid leukemias. Consistently, adult immature T- ALLs showed characteristic mutations in myeloid specific oncogenes and tumor suppressors including IDH1, IDH2, DNMT3A, FLT3 and NRAS. Moreover, we identified ETV6 mutations as a novel genetic lesion uniquely present in immature adult T-ALL. All together, our results demonstrate that early immature adult T- ALL represents a heterogeneous category of leukemias characterized by the presence of overlapping myeloid and T-ALL characteristics and highlight the role of ETV6 mutations in these tumors.
ETV6 mutations in early immature human T cell leukemias.
Specimen part
View SamplesGlucocorticoid resistance is a major driver of therapeutic failure in T-cell acute lymphoblastic leukemia (T-ALL). Here we used a systems biology approach, based on the reverse engineering of signaling regulatory networks, which identified the AKT1 kinase as a signaling factor driving glucocorticoid resistance in T-ALL. Indeed, activation of AKT1 in T-ALL lymphoblasts impairs glucocorticoid-induced apoptosis. Mechanistically, AKT1 directly phosphorylates the glucocorticoid receptor NR3C1 protein at position S134 and blocks glucocorticoid-induced NR3C1 translocation to the nucleus. Consistently, inhibition of AKT1 with MK-2206 increases the response of T-ALL cells to glucocorticoid therapy both in T-ALL cell lines and in primary patient samples thus effectively reversing glucocorticoid resistance in vitro and in vivo. These results warrant the clinical testing of ATK1 inhibitors and glucocorticoids, in combination, for the treatment of T-ALL.
Direct reversal of glucocorticoid resistance by AKT inhibition in acute lymphoblastic leukemia.
Specimen part
View SamplesGlucocorticoid resistance is a major driver of therapeutic failure in T-cell acute lymphoblastic leukemia (T-ALL). Here we identify the AKT1 kinase as a signaling factor driving glucocorticoid resistance in T-ALL. Mechanistically, AKT1 directly phosphorylates the glucocorticoid receptor NR3C1 protein and blocks glucocorticoid-induced NR3C1 transcription by inhibiting glucocorticoid-induced NT3C1 translocation to the nucleus. Consistently, pharmacologic inhibition of AKT1 increases the response of T-ALL cells to glucocorticoid therapy and effectively reverses glucocorticoid resistance in vitro and in vivo. These results warrant the clinical testing of AKT1 inhibitors and glucocorticoids in combination for the treatment of T-ALL.
Direct reversal of glucocorticoid resistance by AKT inhibition in acute lymphoblastic leukemia.
Cell line
View SamplesT-cell acute lymphoblastic leukemia (T-ALL) is an immature hematopoietic malignancy driven mainly by oncogenic activation of NOTCH1 signaling. In this study we used a mouse model of T-ALL through the overexpression of the intarcellular transcriptionally active part of Notch1 (N1-IC). This model faithfully recapitulates the major characteristics of the human disease. Comparison of the leukemic cells from peripheral tumors(thymoma) of this mouse model to normal thymic cells Double Positive (DP) for the markers CD4 and CD8 that express very low levels of Notch1 showed major expression changes in pathways controlling the transition from physiology to disease. Further correlation of the data to ChIP-Seq data from the same cell populations led us to identify a hitherto unknown antagonism of the Notch1 oncogenic pathway and the polycomb complex (PRC2) in leukemia. Importantly exome sequencing in primary samples from human patients with T-ALL revealed that the PRC2 complex is frequently mutated and inactivated, further supporting the tumor suppressor role of the complex in this disease.
Genetic inactivation of the polycomb repressive complex 2 in T cell acute lymphoblastic leukemia.
Specimen part, Disease
View SamplesTransgenic expression of TLX1 induces T-cell leukemias in mice.
The TLX1 oncogene drives aneuploidy in T cell transformation.
No sample metadata fields
View SamplesVelo-cardio-facial syndrome/DiGeorge syndrome/22q11.2 deletion syndrome (22q11DS) patients have a submucous cleft palate, velo-pharyngeal insufficiency associated with hypernasal speech, facial muscle hypotonia and feeding difficulties. Inactivation of both alleles of mouse Tbx1, encoding a T-box transcription factor, deleted on 22q11.2, results in a cleft palate and a reduction or loss of branchiomeric muscles. To identify genes downstream of Tbx1 for myogenesis, gene profiling was performed on mandibular arches (MdPA1) from Tbx1+/+ and Tbx1-/- mouse embryos.
Tbx1 is required autonomously for cell survival and fate in the pharyngeal core mesoderm to form the muscles of mastication.
Specimen part
View SamplesVelo-cardio-facial syndrome/DiGeorge syndrome/22q11.2 deletion syndrome (22q11DS) patients have a submucous cleft palate, velo-pharyngeal insufficiency associated with hypernasal speech, facial muscle hypotonia and feeding difficulties. Inactivation of both alleles of mouse Tbx1, encoding a T-box transcription factor, deleted on 22q11.2, results in a cleft palate and a reduction or loss of branchiomeric muscles. To identify genes downstream of Tbx1 for myogenesis, gene profiling was performed on mandibular arches (MdPA1) from Tbx1+/+ and Tbx1-/- mouse embryos.
Tbx1 is required autonomously for cell survival and fate in the pharyngeal core mesoderm to form the muscles of mastication.
Specimen part
View SamplesCholestasis may cause cholemic nephropathy that can be modelled in common bile duct ligated (CBDL) mice. We aimed to explore the therapeutic efficacy and mechanisms of norursodeoxycholic acid (norUDCA) in cholemic nephropathy. To determine whether norUrsodeoxycholic acid (norUDCA) prevents cholemic nephropathy in long-term CBDL mice, a norUDCA-enriched diet (0.125% w/v, corresponding to 200 mg/kg/day for a mouse of 25 g body weight eating about 4g daily) or a standard mouse diet (Sniff, Soest, Germany) were started 5 days prior to CBDL and were continued until harvesting 3 weeks thereafter. For transcriptional profiling using microarray technology, we compared sham-operated (SOP) mice and 3-week CBDL mice that were either fed 0.125% norUDCA-enriched or standard mouse diets.
NorUrsodeoxycholic acid ameliorates cholemic nephropathy in bile duct ligated mice.
Specimen part
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