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Query: EC:2.7.10.2 (
focal adhesion kinase
)
44,029
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
BCR-
ABL
expression led to a dramatic up-regulation of the IL-3, IL-5, and granulocyte-macrophage colony-stimulating factor receptor beta common (IL-3Rbetac) and IL-3 receptor beta (IL-3Rbeta) chains in murine embryonic stem cell-derived hematopoietic cells coincident with an expansion of multipotent progenitors and myeloid elements. This up-regulation required BCR-
ABL
tyrosine kinase activity and led to IL-3Rbetac/beta chain tyrosine phosphorylation in the absence of detectable IL-3 production. These results suggested that cytokine-independent IL-3 receptor activation could be a dominant signaling component in BCR-
ABL
-induced leukemogenesis. To unambiguously define the significance of IL-3 receptor-dependent signaling in BCR-
ABL
-induced leukemogenesis, BCR-
ABL
-transduced bone marrow cells deficient in either IL-3Rbetac chain or both IL-3Rbetac/beta chain expression were examined for their ability in generating
myeloproliferative disease
(
MPD
). These BCR-
ABL
-expressing knockout cells were capable of generating
MPD
similar to control cells, demonstrating that IL-3 receptor activation is not essential for BCR-
ABL
-induced
MPD
. However, the IL-3Rbetac/beta chain could act as a cofactor in BCR-
ABL
-induced leukemogenesis by activation of its many known oncogenic signaling pathways.
...
PMID:IL-3 receptor signaling is dispensable for BCR-ABL-induced myeloproliferative disease. 1450 Aug 98
Chronic
myeloproliferative disorders
(CMPD) are neoplastic disorders of the hematopoietic stem cell. Four different entities are defined: chronic myeloid leukemia (CML), polycythemia vers, essential thrombocythaemia, and idiopathic myelofibrosis. In addition, overlapping entities within the CMPDs and between CMPDs and myelodysplastic syndrome have been described. Diagnostic measures are performed to classify the subtype exactly and to assess risk factors and prognosis. Cytogenetic and molecular analyses are mandatory for the characterization of the malignant clone. Hydroxyurea and interferon-alpha have proven effective in all CMPE. In CML, specific inhibition of the elevated
ABL
tyrosine kinase activity with imatinib is associated with high response rates. Allogeneic stem cell transplantation is the only curative treatment option for all entities. In CML, the decision-making analysis should be based on established scores. In BCR-
ABL
negative CMPDs an allogeneic stem cell transplantation should only be performed in patients with unfavorable prognosis.
...
PMID:[Chronic myeloproliferative diseases. Diagnosis and therapy]. 1467 16
Chronic myeloid leukemia (CML) is a malignant
myeloproliferative disorder
originating from a pluripotent hematopoietic stem cell that acquires a Philadelphia (Ph) chromosome encoding the BCR-
ABL
oncogenic fusion protein. This molecular abnormality that is thought to be causative in CML was the first acquired chromosome translocation associated with a human malignancy. This chromosomal translocation also makes it possible to precisely distinguish between residual normal (i.e., Ph-, BCR-
ABL
-) progenitor or stem cells and their leukemic counterpart, Ph+ or BCR-ABL+ progenitor/stem cells in every given sample of a patient with CML. This has provided seminal insights into the molecular and cellular biology of leukemia and also of the process of normal hematopoiesis. CML has become a fascinating model disease for malignancy in general.
...
PMID:Hematopoietic stem cells in chronic myeloid leukemia. 1473 89
We report a case of BCR-
ABL
-negative atypical chronic myeloid leukemia (CML) with translocation t(4;22) (q12;q11.2) juxtaposing the breakpoint cluster region (BCR) and platelet-derived growth factor receptor-alpha (PDGFRA) genes. The patient was a 57-year-old man with a history of stage IV diffuse large B-cell lymphoma, status post-6 cycles of combination chemotherapy in 1999, who presented in August 2002 with enlarged lymph nodes, anemia, and marked leukocytosis (50 x 10(9) g/dL) consistent with a
myeloproliferative disorder
(
MPD
). A bone marrow biopsy showed granulocytic hyperplasia, neutrophilia, and mild eosinophilia. Initial cytogenetic evaluation by interphase FISH for BCR-
ABL
, to rule out a translocation 9;22, showed a variant signal pattern consistent with rearrangement of BCR at 22q11.2, but not
ABL
at 9q34. Analysis of the patient's cDNA by polymerase chain reaction (PCR) for BCR-
ABL
was negative. Cytogenetic analysis showed an abnormal karyotype with rearrangement of chromosomes 4 and 22. PCR amplification and subsequent sequence analysis demonstrated an in-frame 5'-BCR/3'-PDGFRA fusion in the patient's cDNA. PDGFRA encodes a receptor tyrosine kinase and shares structural and organizational homology with the KIT and CSf1R receptor genes. However, although the incidence of
MPD
involving translocations of PDGFRB has been well established, to our knowledge there are only two previous reports describing a BCR-PDGFRA fusion gene, in 3 patients diagnosed with atypical CML. Here, we report the molecular and cytogenetic characterization of a patient with BCR-PDGFRA-positive
MPD
who had a complete hematologic response after treatment with imatinib mesylate.
...
PMID:Molecular and cytogenetic characterization of a novel translocation t(4;22) involving the breakpoint cluster region and platelet-derived growth factor receptor-alpha genes in a patient with atypical chronic myeloid leukemia. 1503 67
Polycythemia vera (PV) is a
myeloproliferative disorder
arising in a multipotent hematopoietic stem cell. The pathogenesis of PV remains poorly understood; however, the biologic hallmark of this disease is the presence of erythropoietin (Epo)-independent colony formation (endogenous erythroid colony [EEC]) and cytokine hypersensitivity. We have developed a simple liquid culture from CD34+ cells to study PV erythroid differentiation. PV erythroid differentiation was characterized in this culture system by two types of abnormalities: 1) an increased proliferation of progenitors in response to cytokines, associated with strict cytokine dependency for preventing apoptosis; and 2) Epo-independent terminal erythroid differentiation in the presence of stem cell factor and interleukin-3 as evidenced by the acquisition of glycophorin A. The level of Epo-independent terminal differentiation correlates in PV patients with the number of EEC. Epo-independent terminal differentiation as well as normal Epo-induced differentiation were repressed by inhibitors of
JAK2
(AG490), PI3K (LY294002), and the Src family kinases (PP2). In contrast, an inhibitor of the ERK/MAP kinase pathway (PD98059) had no effect on Epo-independent terminal differentiation. These signaling abnormalities were not mediated by a decreased expression or activity of the membrane tyrosine phosphatase CD45, which dephosphorylates
JAK2
and Src family kinases. This study demonstrates that early steps of PV erythroid differentiation are strictly cytokine dependent. In contrast, late erythroid differentiation is an Epo-independent phenomenon that is mediated by signaling pathways identical to those in Epo-induced differentiation.
...
PMID:Multiple signaling pathways are involved in erythropoietin-independent differentiation of erythroid progenitors in polycythemia vera. 1510 79
Mutations of the c-kit gene have been reported in
myeloproliferative disorders
. We describe here a case of Ph+ (b2a2) chronic myelogenous leukemia that, during the course of disease, showed an unusual bone marrow mast-cell infiltration. A mutational screening for the c-kit gene, performed on DNA routinely cryopreserved during the follow-up, evidenced the D816Y-activating mutation as an additional genetic abnormality. Treatment with imatinib mesylate resulted in a substantial decrease of the BCR-
ABL
/
ABL
ratio and in the absence of c-kit mutation. It is likely that the superimposed c-kit mutation, in this case, may account for the transient bone marrow mastocytosis.
...
PMID:Chronic myelogenous leukemia with acquired c-kit activating mutation and transient bone marrow mastocytosis. 1516 15
Of the current mouse chronic myelogenous leukemia (CML) models,the murine bone marrow (BM) transduction and transplantation model most efficiently mimics many of the central features of human CML. In this model, lethally irradiated mice are reconstituted with primary murine BM cells transduced with a P210BCR/
ABL
retrovirus. All recipient mice develop a fatal peripheral blood and BM granulocytosis and splenomegaly, a disease termed the murine CML-like
myeloproliferative disorder
. This model has been used to establish the causative role of Bcr/Abl in CML, identify those signaling pathways and regions of Bcr/Abl critical for leukemogenesis, and explore the limitations of targeted CML therapy. Future refinements in this CML mouse model will make it a more effective tool for studying imatinib-resistant CML, reproducing chronic- and blastic-phase human CML, and performing CML progenitor studies.
...
PMID:Animal models of chronic myelogenous leukemia. 1527 91
Donor leukocyte infusion (DLI) can induce graft-versus-leukemia (GvL) reactions in patients with chronic myeloid leukemia (CML) relapsing after allogeneic bone marrow transplantation (BMT), but the mechanisms of the antileukemic effect of DLI are unknown, and the procedure is complicated by graft-versus-host disease (GvHD) and graft failure. Here, we adapted a murine retroviral BMT model of Philadelphia(+) leukemia by combining allogeneic bone marrow (BM) from C57Bl/6 (H-2(b)) mice with BCR-
ABL
-transduced Balb/c (H-2(d)) BM, inducing mixed chimerism and
myeloproliferative disease
in recipients resembling relapse of CML following allogeneic BMT. Infusions of allogeneic splenocytes eliminated BCR-
ABL
-induced CML-like disease in the majority of mixed chimeras, with significant GvL effects mediated by both CD4(+) and CD4(-) cells. BCR-
ABL
-induced acute B-lymphoblastic leukemia was also eradicated by DLI in major histocompatibility complex (MHC)-mismatched chimeras. Most DLI-treated mice converted to full allogeneic chimerism but succumbed frequently to GvHD or graft failure. When MHC-matched B10.D2 (H-2(d)) mice were the allogeneic donors, CML-like disease was more resistant to DLI. These results suggest that depletion of CD8(+) cells from DLI could impair GvL against CML, while increased MHC disparity between donor and recipient may improve the responsiveness of Philadelphia(+) B-lymphoblastic leukemia to DLI.
...
PMID:Adoptive immunotherapy of BCR-ABL-induced chronic myeloid leukemia-like myeloproliferative disease in a murine model. 1530 67
Several groups have demonstrated that a submicroscopic gene deletion in Ph+ chronic myelogenous leukemia (CML) is associated with a poor prognosis and reduced response to treatment. To assess the variation between detection methods in the interpretation of a submicroscopic gene deletion, we performed an extra signal (ES)-FISH BCR/ABL and double-FISH (D-FISH) BCR/ABL on frozen bone marrow cells from 79 patients with CML (63 in the chronic phase, 6 in the accelerated phase, and 10 in blast crisis) and 30 patients with a BCR/ABL-negative
myeloproliferative disorder
as determined by RT-PCR. The normal cutoff values were 0.22% for ES-FISH and 0.25% for D-FISH. The cutoff values for false-positive signals from a juxtaposition of the BCR and
ABL
gene were 11% in ES-FISH and 13% in D-FISH. Of the 14 patients who showed an
ABL
gene deletion by ES-FISH, 5 had an
ABL
deletion only, 5 had both a BCR and an
ABL
deletion, but 4 proved to have a classic BCR/ABL rearrangement without a submicroscopic deletion, as determined by D-FISH. Discrepant results between ES- and D-FISH were observed in 12 of the 79 patients (15.8%), and the main causes of a discrepancy were a false-positive
ABL
deletion (4 of 12, 33%), a variant Philadelphia chromosome (3 of 12, 25%), an inversion of derivative chromosome 9 at the very breakpoint of the
ABL
gene (9q32) (1 of 12, 8.3%), a cryptic variant Ph chromosome (1 of 12, 8.3%), and a marker chromosome (1 of 12, 8.3%). Although there was no significant difference in the sensitivity for the detection of the fusion signal between ES- and D-FISH, ES-FISH showed a high percentage of cells with false-positive fusion signals (1 orange, 1 green, 1 yellow), which makes it difficult to interpret the submicroscopic
ABL
deletion. In conclusion, an interpretation of the submicroscopic deletions of the BCR or
ABL
gene should not depend on ES-FISH.
...
PMID:Interpretation of submicroscopic deletions of the BCR or ABL gene should not depend on extra signal-FISH: problems in interpretation of submicroscopic deletion of the BCR or ABL gene with extra signal-FISH. 1572 38
Myeloproliferative disorders
are clonal haematopoietic stem cell malignancies characterized by independency or hypersensitivity of haematopoietic progenitors to numerous cytokines. The molecular basis of most
myeloproliferative disorders
is unknown. On the basis of the model of chronic myeloid leukaemia, it is expected that a constitutive tyrosine kinase activity could be at the origin of these diseases. Polycythaemia vera is an acquired
myeloproliferative disorder
, characterized by the presence of polycythaemia diversely associated with thrombocytosis, leukocytosis and splenomegaly. Polycythaemia vera progenitors are hypersensitive to erythropoietin and other cytokines. Here, we describe a clonal and recurrent mutation in the JH2 pseudo-kinase domain of the
Janus kinase 2
(
JAK2
) gene in most (> 80%) polycythaemia vera patients. The mutation, a valine-to-phenylalanine substitution at amino acid position 617, leads to constitutive tyrosine phosphorylation activity that promotes cytokine hypersensitivity and induces erythrocytosis in a mouse model. As this mutation is also found in other
myeloproliferative disorders
, this unique mutation will permit a new molecular classification of these disorders and novel therapeutical approaches.
...
PMID:A unique clonal JAK2 mutation leading to constitutive signalling causes polycythaemia vera. 1579 61
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