Similar Datasets
Project description:Animal models offer a valuable tool to recapitulate genetically defined subtypes of AML, and to assess the potential of compound mutations and clonal evolution during disease progression. This is of utmost importance for difficult to treat leukemias such as FLT3-ITD positive AML. While conditional gene targeting by Cre-recombinase is a powerful technology that has revolutionized biomedical research, consequences of Cre-expression such as lack of fidelity, toxicity or off-target effects need to be taken into consideration. We report on a transgenic murine model of FLT3-ITD induced disease, where Cre-recombinase expression alone, and in the absence of a conditional allele, gives rise to an aggressive leukemia phenotype. Here, expression of various Cre-recombinases leads to polyclonal expansion of FLT3ITD/ITD progenitor cells, induction of a differentiation block and activation of Myc-dependent gene expression programs. Our report is intended to alert the scientific community of potential risks associated with using this specific mouse model and of unexpected effects of Cre-expression when investigating cooperative oncogenic mutations in murine models of cancer.
2023-02-08 | GSE212221 | GEO
Project description:Animal models offer a valuable tool to recapitulate genetically defined subtypes of AML, and to assess the potential of compound mutations and clonal evolution during disease progression. This is of utmost importance for difficult to treat leukemias such as FLT3-ITD positive AML. While conditional gene targeting by Cre-recombinase is a powerful technology that has revolutionized biomedical research, consequences of Cre-expression such as lack of fidelity, toxicity or off-target effects need to be taken into consideration. We report on a transgenic murine model of FLT3-ITD induced disease, where Cre-recombinase expression alone, and in the absence of a conditional allele, gives rise to an aggressive leukemia phenotype. Here, expression of various Cre-recombinases leads to polyclonal expansion of FLT3ITD/ITD progenitor cells, induction of a differentiation block and activation of Myc-dependent gene expression programs. Our report is intended to alert the scientific community of potential risks associated with using this specific mouse model and of unexpected effects of Cre-expression when investigating cooperative oncogenic mutations in murine models of cancer.
2023-02-08 | GSE212220 | GEO
Project description:Animal models offer a valuable tool to recapitulate genetically defined subtypes of AML, and to assess the potential of compound mutations and clonal evolution during disease progression. This is of utmost importance for difficult to treat leukemias such as FLT3-ITD positive AML. While conditional gene targeting by Cre-recombinase is a powerful technology that has revolutionized biomedical research, consequences of Cre-expression such as lack of fidelity, toxicity or off-target effects need to be taken into consideration. We report on a transgenic murine model of FLT3-ITD induced disease, where Cre-recombinase expression alone, and in the absence of a conditional allele, gives rise to an aggressive leukemia phenotype. Here, expression of various Cre-recombinases leads to polyclonal expansion of FLT3ITD/ITD progenitor cells, induction of a differentiation block and activation of Myc-dependent gene expression programs. Our report is intended to alert the scientific community of potential risks associated with using this specific mouse model and of unexpected effects of Cre-expression when investigating cooperative oncogenic mutations in murine models of cancer.
2023-02-08 | GSE212218 | GEO
Project description:Animal models offer a valuable tool to recapitulate genetically defined subtypes of AML, and to assess the potential of compound mutations and clonal evolution during disease progression. This is of utmost importance for difficult to treat leukemias such as FLT3-ITD positive AML. While conditional gene targeting by Cre-recombinase is a powerful technology that has revolutionized biomedical research, consequences of Cre-expression such as lack of fidelity, toxicity or off-target effects need to be taken into consideration. We report on a transgenic murine model of FLT3-ITD induced disease, where Cre-recombinase expression alone, and in the absence of a conditional allele, gives rise to an aggressive leukemia phenotype. Here, expression of various Cre-recombinases leads to polyclonal expansion of FLT3ITD/ITD progenitor cells, induction of a differentiation block and activation of Myc-dependent gene expression programs. Our report is intended to alert the scientific community of potential risks associated with using this specific mouse model and of unexpected effects of Cre-expression when investigating cooperative oncogenic mutations in murine models of cancer.
2023-02-08 | GSE212216 | GEO
Project description:Animal models offer a valuable tool to recapitulate genetically defined subtypes of AML, and to assess the potential of compound mutations and clonal evolution during disease progression. This is of utmost importance for difficult to treat leukemias such as FLT3-ITD positive AML. While conditional gene targeting by Cre-recombinase is a powerful technology that has revolutionized biomedical research, consequences of Cre-expression such as lack of fidelity, toxicity or off-target effects need to be taken into consideration. We report on a transgenic murine model of FLT3-ITD induced disease, where Cre-recombinase expression alone, and in the absence of a conditional allele, gives rise to an aggressive leukemia phenotype. Here, expression of various Cre-recombinases leads to polyclonal expansion of FLT3ITD/ITD progenitor cells, induction of a differentiation block and activation of Myc-dependent gene expression programs. Our report is intended to alert the scientific community of potential risks associated with using this specific mouse model and of unexpected effects of Cre-expression when investigating cooperative oncogenic mutations in murine models of cancer.
2023-02-08 | GSE212214 | GEO
Project description:Acute myeloid leukemia (AML) is induced by the cooperative action of deregulated genes that perturb self-renewal, proliferation, and differentiation. Internal tandem duplications (ITDs) in the FLT3 receptor tyrosine kinase are common mutations in AML, confer poor prognosis, and stimulate myeloproliferation. AML patient samples with FLT3-ITD express high levels of RUNX1, a transcription factor with known tumor-suppressor function. In this study, to understand this paradox, we investigated the impact of RUNX1 and FLT3-ITD coexpression. FLT3-ITD directly impacts on RUNX1 activity, whereby up-regulated and phosphorylated RUNX1 cooperates with FLT3-ITD to induce AML. Inactivating RUNX1 in tumors releases the differentiation block and down-regulates genes controlling ribosome biogenesis. We identified Hhex as a direct target of RUNX1 and FLT3-ITD stimulation and confirmed high HHEX expression in FLT3-ITD AMLs. HHEX could replace RUNX1 in cooperating with FLT3-ITD to induce AML. These results establish and elucidate the unanticipated oncogenic function of RUNX1 in AML. We predict that blocking RUNX1 activity will greatly enhance current therapeutic approaches using FLT3 inhibitors.
| S-EPMC5339673 | biostudies-literature
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.
| S-EPMC3301423 | biostudies-literature
Project description:Death-associated protein kinase 1 (DAPK1), a tumor suppressor, is a rate-limiting effector in an endoplasmic reticulum (ER) stress-dependent apoptotic pathway. Its expression is epigenetically suppressed in several tumors. A mechanistic basis for epigenetic/transcriptional repression of DAPK1 was investigated in certain forms of acute myeloid leukemia (AML) with poor prognosis, which lacked ER stress-induced apoptosis.Heterogeneous primary AMLs were screened to identify a subgroup with Flt3ITD in which repression of DAPK1, among NF-?B-and c-Jun-responsive genes, was studied. RNA interference knockdown studies were carried out in an Flt3ITD(+) cell line, MV-4-11, to establish genetic epistasis in the pathway Flt3ITD-TAK1-DAPK1 repression, and chromatin immunoprecipitations were carried out to identify proximate effector proteins, including TAK1-activated p52NF-?B, at the DAPK1 locus.AMLs characterized by normal karyotype with Flt3ITD were found to have 10- to 100-fold lower DAPK1 transcripts normalized to the expression of c-Jun, a transcriptional activator of DAPK1, as compared with a heterogeneous cytogenetic category. In addition, Meis1, a c-Jun-responsive adverse AML prognostic gene signature was measured as control. These Flt3ITD(+) AMLs overexpress relB, a transcriptional repressor, which forms active heterodimers with p52NF-?B. Chromatin immunoprecipitation assays identified p52NF-?B binding to the DAPK1 promoter together with histone deacetylase 2 (HDAC2) and HDAC6 in the Flt3ITD(+) human AML cell line MV-4-11. Knockdown of p52NF-?B or its upstream regulator, NF-?B-inducing kinase (NIK), de-repressed DAPK1. DAPK1-repressed primary Flt3ITD(+) AMLs had selective nuclear activation of p52NF-?B.Flt3ITD promotes a noncanonical pathway via TAK1 and p52NF-?B to suppress DAPK1 in association with HDACs, which explains DAPK1 repression in Flt3ITD(+) AML.
| S-EPMC3918433 | biostudies-literature
Project description:The full-length AML1-ETO (AE) fusion gene resulting from t(8;21)(q22;q22) in human acute myeloid leukemia (AML) is not sufficient to induce leukemia in animals, suggesting that additional mutations are required for leukemogenesis. We and others have identified activating mutations of C-KIT in nearly half of patients with t(8;21) AML. To test the hypothesis that activating C-KIT mutations cooperate with AE to cause overt AML, we generated a murine transduction and transplantation model with both mutated C-KIT and AE. To overcome the intracellular transport block of human C-KIT in murine cells, we engineered hybrid C-KIT (HyC-KIT) by fusing the extracellular and transmembrane domains of the murine c-Kit in-frame to the intracellular signaling domain of human C-KIT. We showed that tyrosine kinase domain mutants HyC-KIT N822K and D816V, as well as juxtamembrane mutants HyC-KIT 571+14 and 557-558Del, could transform murine 32D cells to cytokine-independent growth. The protein tyrosine kinase inhibitor dasatinib inhibited the proliferation of 32D cells expressing these C-KIT mutants, with potency in the low nanomolar range. In mice, HyC-KIT N822K induced a myeloproliferative disease, whereas HyC-KIT 571+14 induces both myeloproliferative disease and lymphocytic leukemia. Interestingly, coexpression of AE and HyC-KIT N822K led to fatal AML. Our data have further enriched the two-hit model that abnormalities of both transcription factor and membrane/cytosolic signaling molecule are required in AML pathogenesis. Furthermore, dasatinib prolonged lifespan of mice bearing AE and HyC-KIT N822K-coexpressing leukemic cells and exerted synergic effects while combined with cytarabine, thus providing a potential therapeutic for t(8;21) leukemia.
| S-EPMC3038718 | biostudies-literature
Project description:Cytoplasmic nucleophosmin (NPMc(+)) mutations and FMS-like tyrosine kinase 3 (FLT3) internal tandem duplication (ITD) mutations are two of the most common known molecular alterations in acute myeloid leukemia (AML); they frequently occur together, suggesting cooperative leukemogenesis. To explore the specific relationship between NPMc+ and FLT3/ITD in vivo, we crossed Flt3/ITD knock-in mice with transgenic NPMc+ mice. Mice with both mutations develop a transplantable leukemia of either myeloid or lymphoid lineage, definitively demonstrating cooperation between Flt3/ITD and NPMc+. In mice with myeloid leukemia, functionally significant loss of heterozygosity of the wild-type Flt3 allele is common, similar to what is observed in human FLT3/ITD+ AML, providing further in vivo evidence of the importance of loss of wild-type FLT3 in leukemic initiation and progression. Additionally, in vitro clonogenic assays reveal that the combination of Flt3/ITD and NPMc+ mutations causes a profound monocytic expansion, in excess of that seen with either mutation alone consistent with the predominance of myelomonocytic phenotype in human FLT3/ITD+/NPMc+ AML. This in vivo model of Flt3/ITD+/NPMc+ leukemia closely recapitulates human disease and will therefore serve as a tool for the investigation of the biology of this common disease entity.
| S-EPMC3932758 | biostudies-literature