GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Knock-in of a FLT3/ITD mutation cooperates with a NUP98-HOXD13 fusion to generate acute myeloid leukemia in a mouse model (2012)
    American Society of Hematology (ASH)
    In: Blood
    Details
    Publication Date: 2012-03-23
    Description: Constitutive activation of FLT3 by internal tandem duplication (ITD) is one of the most common molecular alterations in acute myeloid leukemia (AML). FLT3/ITD mutations have also been observed in myelodysplastic syndrome patients both before and during progression to AML. Previous work has shown that insertion of an FLT3/ITD mutation into the murine Flt 3 gene induces a myeloproliferative neoplasm, but not progression to acute leukemia, suggesting that additional cooperating events are required. We therefore combined the FLT3/ITD mutation with a model of myelodysplastic syndrome involving transgenic expression of the Nup98-HoxD13 ( NHD13 ) fusion gene. Mice expressing both the FLT3/ITD and NHD13 transgene developed AML with 100% penetrance and short latency. These leukemias were driven by mutant FLT3 expression and were susceptible to treatment with FLT3 tyrosine kinase inhibitors. We also observed a spontaneous loss of the wild-type Flt3 allele in these AMLs, further modeling the loss of the heterozygosity phenomenon that is seen in human AML with FLT3-activating mutations. Because resistance to FLT3 inhibitors remains an important clinical issue, this model may help identify new molecular targets in collaborative signaling pathways.
    Keywords: Myeloid Neoplasia
    Print ISSN: 0006-4971
    Electronic ISSN: 1528-0020
    Topics: Biology , Medicine
    Published by American Society of Hematology (ASH)
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 2
    facet.materialart.
    Unknown
    All-trans retinoic acid synergizes with FLT3 inhibition to eliminate FLT3/ITD+ leukemia stem cells in vitro and in vivo (2016)
    American Society of Hematology (ASH)
    In: Blood
    Details
    Publication Date: 2016-06-10
    Description: FMS-like tyrosine kinase 3 (FLT3)-mutant acute myeloid leukemia (AML) portends a poor prognosis, and ineffective targeting of the leukemic stem cell (LSC) population remains one of several obstacles in treating this disease. All- trans retinoic acid (ATRA) has been used in several clinical trials for the treatment of nonpromyelocytic AML with limited clinical activity observed. FLT3 tyrosine kinase inhibitors (TKIs) used as monotherapy also achieve limited clinical responses and are thus far unable to affect cure rates in AML patients. We explored the efficacy of combining ATRA and FLT3 TKIs to eliminate FLT3/internal tandem duplication (ITD) + LSCs. Our studies reveal highly synergistic drug activity, preferentially inducing apoptosis in FLT3/ITD + cell lines and patient samples. Colony-forming unit assays further demonstrate decreased clonogenicity of FLT3/ITD + cells upon treatment with ATRA and TKI. Most importantly, the drug combination depletes FLT3/ITD + LSCs in a genetic mouse model of AML, and prolongs survival of leukemic mice. Furthermore, engraftment of primary FLT3/ITD + patient samples is reduced in mice following treatment with FLT3 TKI and ATRA in combination, with evidence of cellular differentiation occurring in vivo. Mechanistically, we provide evidence that the synergism of ATRA and FLT3 TKIs is at least in part due to the observation that FLT3 TKI treatment upregulates the antiapoptotic protein Bcl6, limiting the drug’s apoptotic effect. However, cotreatment with ATRA reduces Bcl6 expression to baseline levels through suppression of interleukin-6 receptor signaling. These studies provide evidence of the potential of this drug combination to eliminate FLT3/ITD + LSCs and reduce the rate of relapse in AML patients with FLT3 mutations.
    Keywords: Myeloid Neoplasia
    Print ISSN: 0006-4971
    Electronic ISSN: 1528-0020
    Topics: Biology , Medicine
    Published by American Society of Hematology (ASH)
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 3
    facet.materialart.
    Unknown
    TTT-3002 is a novel FLT3 tyrosine kinase inhibitor with activity against FLT3-associated leukemias in vitro and in vivo (2014)
    American Society of Hematology (ASH)
    In: Blood
    Details
    Publication Date: 2014-03-09
    Description: More than 35% of acute myeloid leukemia (AML) patients harbor a constitutively activating mutation in FMS-like tyrosine kinase-3 ( FLT3 ). The most common type, internal tandem duplication (ITD), confers poor prognosis. We report for the first time on TTT-3002, a tyrosine kinase inhibitor (TKI) that is one of the most potent FLT3 inhibitors discovered to date. Studies using human FLT3/ITD mutant leukemia cell lines revealed the half maximal inhibitory concentration (IC 50 ) for inhibiting FLT3 autophosphorylation is from 100 to 250 pM. The proliferation IC 50 for TTT-3002 in these same cells was from 490 to 920 pM. TTT-3002 also showed potent activity when tested against the most frequently occurring FLT3-activating point mutation, FLT3/D835Y, against which many current TKIs are ineffective. These findings were validated in vivo by using mouse models of FLT3-associated AML. Survival and tumor burden of mice in several FLT3/ITD transplantation models is significantly improved by administration of TTT-3002 via oral dosing. Finally, we demonstrated that TTT-3002 is cytotoxic to leukemic blasts isolated from FLT3/ITD-expressing AML patients, while displaying minimal toxicity to normal hematopoietic stem/progenitor cells from healthy blood and bone marrow donors. Therefore, TTT-3002 has demonstrated preclinical potential as a promising new FLT3 TKI in the treatment of FLT3-mutant AML.
    Keywords: Myeloid Neoplasia
    Print ISSN: 0006-4971
    Electronic ISSN: 1528-0020
    Topics: Biology , Medicine
    Published by American Society of Hematology (ASH)
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 4
    facet.materialart.
    Unknown
    Fluvastatin inhibits FLT3 glycosylation in human and murine cells and prolongs survival of mice with FLT3/ITD leukemia (2012)
    American Society of Hematology (ASH)
    In: Blood
    Details
    Publication Date: 2012-10-12
    Description: FLT3 is frequently mutated in acute myeloid leukemia (AML), but resistance has limited the benefit of tyrosine kinase inhibitors (TKI). We demonstrate that statins can impair FLT3 glycosylation, thus leading to loss of surface expression and induction of cell death, as well as mitigation of TKI resistance. Immunofluorescence microscopy confirms a reduction in surface localization and an increase in intracellular FLT3/internal tandem duplication (ITD) accumulation. This aberrant localization was associated with increased STAT5 activation but inhibition of both MAPK and AKT phosphorylation. Growth inhibition studies indicate that FLT3/ITD-expressing cells were killed with an IC 50 within a range of 0.2-2μM fluvastatin. Several mechanisms of resistance could be circumvented by fluvastatin treatment. An increase in the IC 50 for inhibition of phosphorylated FLT3/ITD by lestaurtinib caused by exogenous FLT3 ligand, resistance to sorafenib caused by the D835Y or FLT3/ITD N676K mutations, and activation of the IL-3 compensatory pathway were all negated by fluvastatin treatment. Finally, fluvastatin treatment in vivo reduced engraftment of BaF3 FLT3/ITD cells in Balb/c mice. These results demonstrate that statins, a class of drugs already approved by the US Food and Drug Administration, might be repurposed for the management of FLT3 mutant acute myeloid leukemia cases either alone or in conjunction with FLT3 TKI.
    Keywords: Myeloid Neoplasia
    Print ISSN: 0006-4971
    Electronic ISSN: 1528-0020
    Topics: Biology , Medicine
    Published by American Society of Hematology (ASH)
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...