Dataset Information

Block of C/EBP alpha function by phosphorylation in acute myeloid leukemia with FLT3 activating mutations.

ABSTRACT: Mutations constitutively activating FLT3 kinase are detected in approximately 30% of acute myelogenous leukemia (AML) patients and affect downstream pathways such as extracellular signal-regulated kinase (ERK)1/2. We found that activation of FLT3 in human AML inhibits CCAAT/enhancer binding protein alpha (C/EBPalpha) function by ERK1/2-mediated phosphorylation, which may explain the differentiation block of leukemic blasts. In MV4;11 cells, pharmacological inhibition of either FLT3 or MEK1 leads to granulocytic differentiation. Differentiation of MV4;11 cells was also observed when C/EBPalpha mutated at serine 21 to alanine (S21A) was stably expressed. In contrast, there was no effect when serine 21 was mutated to aspartate (S21D), which mimics phosphorylation of C/EBPalpha. Thus, our results suggest that therapies targeting the MEK/ERK cascade or development of protein therapies based on transduction of constitutively active C/EBPalpha may prove effective in treatment of FLT3 mutant leukemias resistant to the FLT3 inhibitor therapies.

SUBMITTER: Radomska HS

PROVIDER: S-EPMC2118199 | biostudies-literature | 2006 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Block of C/EBP alpha function by phosphorylation in acute myeloid leukemia with FLT3 activating mutations.

Radomska Hanna S HS Bassères Daniela S DS Zheng Rui R Zhang Pu P Dayaram Tajhal T Yamamoto Yukiya Y Sternberg David W DW Lokker Nathalie N Giese Neill A NA Bohlander Stefan K SK Schnittger Susanne S Delmotte Marie-Hélène MH Davis Roger J RJ Small Donald D Hiddemann Wolfgang W Gilliland D Gary DG Tenen Daniel G DG

The Journal of experimental medicine 20060130 2

Mutations constitutively activating FLT3 kinase are detected in approximately 30% of acute myelogenous leukemia (AML) patients and affect downstream pathways such as extracellular signal-regulated kinase (ERK)1/2. We found that activation of FLT3 in human AML inhibits CCAAT/enhancer binding protein alpha (C/EBPalpha) function by ERK1/2-mediated phosphorylation, which may explain the differentiation block of leukemic blasts. In MV4;11 cells, pharmacological inhibition of either FLT3 or MEK1 leads ...[more]

PMID: 16446383

Similar Datasets

Project description:Acute myeloid leukemia (AML) is an aggressive hematologic malignancy which is cured in a minority of patients. A FLT3-internal tandem duplication (ITD) mutation, found in approximately a quarter of patients with de novo AML, imparts a particularly poor prognosis. Patients with FLT3-ITD AML often present with more aggressive disease and have a significantly higher propensity for relapse after remission. The therapeutic approach for these patients has traditionally included intensive induction chemotherapy, followed by consolidative chemotherapy or hematopoietic cell transplantation (HCT). In recent years, multiple small molecule inhibitors of the FLT3 tyrosine kinase have been studied preclinically and in clinical trials. The earlier generation of these agents, often non-specific and impacting a variety of tyrosine kinases, produced at best transient peripheral blood responses in early clinical trials. Additionally, the combination of FLT3 inhibitors with cytotoxic regimens has not, as of yet, demonstrated an improvement in overall survival. Nevertheless, multiple current trials, including those with sorafenib, lestaurtinib, and midostaurin, continue to study the combination of FLT3 inhibitors with standard chemotherapy. Factors such as sustained FLT3 inhibition, protein binding, pharmacokinetics, and the presence of elevated FLT3-ligand levels appear to significantly impact the potency of these agents in vivo. In recent years, the development of more specific and potent agents has generated hope that FLT3 inhibitors may play a more prominent role in the treatment of FLT3-ITD AML in the near future. Nevertheless, questions remain regarding the optimal timing and schedule for incorporation of FLT3 inhibitors. The suitability, type, and timing of allogeneic HCT in the therapeutic approach for these patients are also issues which require further study and definition. Recent retrospective data appears to support the efficacy of allogeneic HCT in first complete remission, possibly due to a graft versus leukemia effect. However, larger prospective studies are necessary to further elucidate the role of HCT and its potential combination with FLT3 inhibitor therapy. We are hopeful that current clinical investigation will lead to an optimization and improvement of outcomes for these patients.

Project description:ObjectiveAmong all types of hematological neoplasms, acute myeloid leukemia (AML) has the highest death rate. Recently, cytogenetic and molecular genetics are crucial in the management, as a consequence of their effect on AML pathogenesis, classification, risk-stratification, prognosis and treatment.Methods100 Syrian adults with Normal Karyotype (NK) newly diagnosed AML patients were included in this study, all cases confirmed histologically and immunohistochemically. Patients were divided into six subgroups using flow cytometry and cytological results. Polymerase chain reaction (PCR) was performed on exon 11-12 for FMS-like tyrosine kinase-3 internal tandem duplication (FLT3-ITD), exon 12 for Nucleophosmin1 (NPM1), and exon 23 for DNA methyltransferase 3A (DNMT3A) using target primers, the electropherograms were analyzed for gene mutations by comparing with the reference DNA sequence. Data were compared and aligned with different sequences using the NCBI BLAST Assembled Genomes tool.ResultsFLT3-ITD, NPM1 and DNMT3A were detected in 24%, 22 % and 4% patients respectively. M2 subtype had the most frequent incidence of diagnosis in AML. FLT3-ITD mutation patients had the highest mean of death cases, while the DNMT3A mutation patients had the lowest. On the other hand, the highest mean of remission was in patients with NPM1 mutation and the lowest in the carriers of the FLT3-ITD mutation. It was observed that the mean relapsed patients with FLT3-ITD and DNMT3A mutation was 3.4 and 2 months respectively, with no significant differences between (FLT3-ITD and DNMT3A) carriers and non-carriers relapsed. On the contrary, the mean relapsed for NPM1 mutation carriers was 2.4 months with significant statistical differences. The mean survival time for patients with FLT3-ITD and NPM1 mutation was 5.9 months and 5.85 months respectively, with significant correlation. Between it was 5.88 months in DNMT3A patients with no significant differences. Finally, It was noted that the mean event free survival (EFS) of FLT3-ITD mutation patients was 4.818 months and the mean EFS of NPM1 mutation patients was 4.805 months, with significant statistical differences (p<0.05) between the mutation patients and non-mutated patients regarding to EFS, While this mean was not statistically significant in patients carrying DNMT3A mutation.ConclusionPatients with FLT3-ITD and NPM1 mutations have the worst prognosis, where the presence of those mutations was significantly related to overall survival (OS) and EFS. Our study reflects that DNMT3A was not an extremely bad prognostic effect as an independent factor. We can declare according to this study that genetic mutation and variants detection could easily be incorporated into the regimen evaluation of AML patients.

Dataset Information

Block of C/EBP alpha function by phosphorylation in acute myeloid leukemia with FLT3 activating mutations.

Publications

Block of C/EBP alpha function by phosphorylation in acute myeloid leukemia with FLT3 activating mutations.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets