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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)
We have previously reported that the Jak2 tyrosine kinase but not Jak1 is tyrosine phosphorylated in the absence of IL-3 in Bcr-Abl positive M3.16 cells, which are rendered IL-3 independent by BCR-
ABL
gene expression. We have explored the involvement of Jak2 tyrosine phosphorylation in Bcr-Abl oncogenic effects. Our results indicate that Jak2 became tyrosine-phosphorylated in a number of cell lines expressing Bcr-Abl, when maintained in medium lacking IL-3, whereas Bcr-Abl negative cells lacked Jak2 tyrosine phosphorylation. Jak2 was poorly tyrosine-phosphorylated in cells expressing the SH2 deletion mutant of Bcr-Abl compared to either wild-type Bcr-Abl or its SH3 deletion mutant. Moreover, tyrosine phosphorylation of Jak2 by Bcr-Abl was inhibited by the Abl tyrosine kinase inhibitor, STI 571, in a dose-dependent manner. This inhibition of Bcr-Abl kinase by the drug did not interfere with the ability of Jak2 and Bcr-Abl to form a complex. Studies with deletion mutants of Bcr-Abl indicated that the C-terminal domain of Abl within Bcr-Abl was involved in complex formation with Jak2. Similarly, GST-Abl pull-down assays confirmed the strong binding to Jak2 by the C-terminus of Abl. Jak2 peptide substrate studies indicated that the Bcr-Abl and Abl tyrosine kinases specifically phosphorylated Y1007 of Jak2 but only poorly phosphorylated Y1008. Phosphorylation of Y1007 of Jak2 is known to be critical for its tyrosine kinase activation. Tyrosine residue 1007 of Jak2 was phosphorylated in 32Dp210 cells as measured by Western blotting with a phosphotyrosine 1007 sequence-specific antibody. A kinase-inactive Jak2 mutant blocked the colony forming ability of K562 cells. Tumor formation of K562 cells in nude mice was similarly inhibited by this kinase-inactive Jak2 mutant. This inhibition was independent of Stat5 tyrosine phosphorylation. Furthermore, tyrosine-phosphorylated Jak2 was detected in blood cells from
CML
patients in blast crisis but not in a normal marrow sample. In summary, these findings provide strong evidence that the Jak2 tyrosine kinase is a critical factor in Bcr-Abl malignant transformation.
...
PMID:Involvement of Jak2 tyrosine phosphorylation in Bcr-Abl transformation. 1159 27
The treatment of
CML
with IFN alpha is limited due to resistance against this substance. Recent studies with different cells than chronic myelogenous leukemic cells revealed a synergistic effect of a combined use of Retinoids (RA) and IFN alpha. The purpose of the study was to detect possible interactions of IFN alpha and RA in
CML
considering also the effect of the BCR-
ABL
gene-product. Therefore, we investigated three
CML
cell lines in their proliferation after incubation with IFN alpha and Retinoids alone and in combination. We measured low susceptibility to IFN alpha but a marked influence of the Retinoids. In combination, the growth inhibition was enhanced potentially in response to an increased efficacy of IFN alpha. Even solely, ineffective concentrations of both substances lead to decreased proliferation.
...
PMID:13cis- and all-trans retinoic acid have antiproliferative effects on CML cells and render IFN alpha antiproliferative potency after combined treatment in vitro. 1160 3
The Ph chromosome has been genetically linked to
CML
and ALL. Its chimeric fusion gene product, BCR-
ABL
, can generate leukemia in mice. This review will discuss selected model systems developed to study BCR-
ABL
induced leukemia and focuses on what we have learned about the human disease from these models. Five main experimental approaches will be discussed including: (i) Reconstitution of mice with bone marrow cells retrovirally transduced with BCR-
ABL
; (ii) Transgenic mice expressing BCR-
ABL
; (iii) Knock-in mice with BCR-
ABL
expression driven from the endogenous bcr locus; (iv) Development of
CML
-like disease in mice with loss of function mutations in heterologous genes; and (v) ES in vitro hematopoietic differentiation coupled with regulated BCR-
ABL
expression.
...
PMID:Modeling Philadelphia chromosome positive leukemias. 1160 16
The t(9;22)(q34;q11) produces the BCR/ABL fusion gene which codifies a 210 kb protein with a strong tyrosine kinase activity and is involved in cellular development and growth. Because this translocation is a reciprocal event, it could give rise to a second fusion gene,
ABL
-BCR, on the derivative 9q+. We analyzed the influence of the 3' M-BCR deletion on the clinical picture at diagnosis and disease outcome in 57 patients with a clinical diagnosis of
CML
. Molecular studies were done on DNA from peripheral blood leukocytes or bone marrow with the restrictions enzymes BglII, EcoRI, HindIII, and BamHI, and the BCR 3' probe (transprobe 1) (Oncogene Science Inc.), which encompasses almost all of the 5.8 Kb of the M-BCR gene area. In 18 patients Southern blot analysis showed deletion of the 3' end of BCR gene (32.7%). There were no significant differences between patients with or without deletion, either in the clinical and laboratory data at the disease diagnosis or at the disease outcome. The absence of differences between the patients with and without 3' BCR deletion supports the hypothesis that the hybrid gene
ABL
-BCR does not have an important role in leukemogenesis in
CML
cases.
...
PMID:Deletion of BCR region 3' in chronic myelogenous leukemia. 1167 77
Serial assays of qualitative (multiplex and nested) and quantitative PCR were carried out for detecting and estimating the level of BCR-
ABL
transcripts in 39
CML
patients following bone marrow transplantation. Seven of these patients, who received donor lymphocyte infusions (DLIs) following to relapse, were also monitored. Quantitative estimates of BCR-
ABL
transcripts were obtained by co-amplification with a competitor sequence. Estimates of
ABL
transcripts were used, an internal control and the ratio BCR-
ABL
/
ABL
was thus estimated for evaluating the kinetics of residual clones. Twenty four patients were followed shortly after BMT; two of these patients were in cytogenetic relapse coexisting with very high BCR-
ABL
levels while other 22 were in clinical, haematologic and cytogenetic remission 2-42 months after BMT. In this latter group, seven patients showed a favourable clinical-haematological progression in association with molecular remission while in 14 patients quantitative PCR assays indicated molecular relapse that was not associated with an early cytogenetic-haematologic relapse. BCR-
ABL
/
ABL
levels could not be correlated with presence of GVHD in 24 patients after BMT. In all seven patients treated with DLI, high levels of transcripts were detected at least 4 months before the appearance of clinical haematological relapse. Following DLI, five of these patients showed decreasing transcript levels from 2 to 5 logs between 4 and 12 months. In eight other patients studied long after BMT, five showed molecular relapse up to 117 months post-BMT and only one showed cytogenetic relapse. Our findings indicated that quantitative estimates of BCR-
ABL
transcripts were valuable for monitoring minimal residual disease in each patient.
...
PMID:Estimations of BCR-ABL/ABL transcripts by quantitative PCR in chronic myeloid leukaemia after allogeneic bone marrow transplantation and donor lymphocyte infusion. 1175 63
Since STI571, a BCR-
ABL
tyrosine kinase inhibitor, has made a great therapeutic advance in the management of
CML
, we have to reconsider the treatment protocol for chronic phase CML. Interferon-alpha (IFN-alpha) will be replaced with STI571 therapy. However, some patients are reported to become refractory to STI571, and it is unclear whether STI571 therapy alone may be sufficient to induce long-term survival in
CML
. There are also important progress in the field of allogeneic hematopoietic stem cell transplantation (SCT); i.e. minitransplant(non-myeloablative SCT) and cord blood stem cell transplantation. Currently, newly-diagnosed
CML
patients in chronic phase should be initially treated with STI571. If the patients are appropriate candidates for allogeneic SCT and have HLA-indentical sibling donors, allogeneic SCT should be conducted within one year. The other patients should also receive related or unrelated allogeneic SCT if Ph suppression is insufficient with STI571 therapy for several months. The patients who are not candidates for allogeneic SCT may be treated with IFN-alpha and/or Hydrea(or cytosine arabinoside) in addition to STI571 if they become refractory to STI571. Since each therapeutic modality has different risk and benefits, informed consent is very important to determine the treatment plan for individual patients.
...
PMID:[Treatment plan and informed consent]. 1176 45
A variety of normal human tissues have been reported to harbor small cell populations carrying potentially oncogenic gene rearrangements. This backdrop of mutant cells may be present in the majority of healthy individuals and is apparently weakly selected against. This may provide empirical support for the concept of global neutrality, or near-neutrality (very weak selection), of many somatic mutations. Many healthy individuals, as well as patients with chronic myeloid leukemia, manifest the BCR-ABL fusion gene in blood cells. The presumed neutrality of the BCR-
ABL
rearrangement-carrying pluripotential hematopoietic stem cells and the relative uniformity of the incidence rate of
CML
worldwide were used to estimate the extent of the background of BCR-
ABL
-positive stem cells and the numerical size of the human pluripotential hematopoietic stem cell pool. Three different approaches (molecular-epidemiological, statistical, and population genetical) were employed. Each resulted in very similar estimates of the size of the stem cells carrying the BCR-
ABL
allele fusions (1.4 x 10(4) cells) and the size of the total human stem cell pool (1.6 x 10(9) cells per individual). The implication of these estimates in the context of the hierarchical nature of the stem cell pool is also considered. The presumptive smaller-sized population of CD34(-) stem cells could not be characterized by any of the approaches used as a "founding" population, representing an ultimate source of all hematopoietic progenitors, or as a subset of stem cells comprising a deeper "kinetic" segment of the total (10(9)-sized) stem cell compartment.
...
PMID:The fundamental prevalence of chronic myeloid leukemia-generating clonogenic cells in the light of the neutrality theory of evolution. 1178 55
For the diagnosis of
CML
and for monitoring of treatment response the detection of the t(9;22)(q34;q11) or the BCR-
ABL
rearrangement is necessary. Chromosome banding analysis (CA) is still the gold standard but other techniques like Southern blot, fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR) are available. We analyzed 350
CML
patients at different stages of disease in parallel with CA, interphase-FISH (IP-FISH), hypermetaphase-FISH (HM-FISH) and RT-PCR. In 20 cases with no Ph(+) metaphases in CA, HM-FISH detected 0.2 to 10% BCR-
ABL
(+)metaphases. After IP-FISH 107 samples were judged as negative. However, in 17 of these samples HM-FISH detected BCR-
ABL
(+) metaphases (0.3-11%), and in eight cases CA detected Ph(+) metaphases (2.5-25%). A comparison of IP-FISH performed on uncultivated cells vs cells cultivated for 48 h in 70 cases revealed a higher proportion of BCR-ABL+ cells in the cultivated samples. If nested PCR was negative, all other methods were negative in all cases too. In addition, 94 cases were evaluated using real-time PCR (LightCycler technology). The BCR-
ABL
/cABL ratio measured showed a high correlation with all other methods. Interestingly, a wide range in the BCR-
ABL
/
ABL
ratio was observed especially in patients who showed 100% Ph-positive metaphases in CA. In conclusion, CA, IP-FISH, HM-FISH and real-time PCR give reliable results but differences due to measurement of different target structures have to be kept in mind when using these data for definition of remission status.
...
PMID:Comparison of chromosome banding analysis, interphase- and hypermetaphase-FISH, qualitative and quantitative PCR for diagnosis and for follow-up in chronic myeloid leukemia: a study on 350 cases. 1184 Feb 63
The tyrosine kinase activity of the BCR/ABL fusion protein is required for the transformation in patients with chronic myeloid leukemia. The tyrosine kinase inhibitor STI571 inhibits the BCR/ABL and
ABL
kinase activity and consequently inhibits growth of BCR/ABL-positive cells. However, resistance to STI571 has been demonstrated in Ph+ cell lines and in
CML
patients and can be explained in some cases by point mutations within the ATP-binding pocket or amplification of the bcr/abl gene. In previous investigations using a nu/nu mouse model, the binding of STI571 to elevated levels of the plasmaprotein -1 acid glycoprotein (AGP) was identified as an additional mechanism of resistance to this therapeutic approach. Here we provide data on the expression of AGP in
CML
patients under therapy with STI571. Patients received 400 or 600 mg STI571 daily and apart from clinical parameters we determined AGP and C-reactive protein (CRP) plasma levels as well as the quantitative expression of both BCR/ABL and AGP mRNA in peripheral blood cells. Our data suggest that despite elevated AGP levels in 52% of our patients, no upfront resistance against STI571 was present. In conclusion, we demonstrated that during the first 13 weeks of STI571 therapy (i) plasma AGP levels in
CML
patients correlate with white blood cell count and stage of disease; (ii) patients with elevated AGP responded less rapidly to STI571; (iii) elevated AGP and CRP levels normalized in patients during treatment with STI571, although mRNA levels of AGP remained stable; (iv) initially normal levels of AGP remained in the normal range during treatment with STI571, indicating that STI571 does not trigger AGP expression in humans; and (v) in relapsed patients, elevation of AGP levels is present prior to hematological progress.
...
PMID:Determination of alpha-1 acid glycoprotein in patients with Ph+ chronic myeloid leukemia during the first 13 weeks of therapy with STI571. 1198 44
We describe two Philadelphia chromosome-positive chronic myeloid leukaemia (Ph-positive
CML
) patients carrying micro-bcr (micro-bcr) breakpoint, who developed blast crisis within 5 years of diagnosis. Reverse transcription polymerase chain reaction analysis of bone marrow cells using primers specific for the p210BCR-
ABL
fusion transcript showed aberrant large-sized bands in both cases (986 bp in patient 1 and 1031 bp in patient 2). Sequencing analysis of these products revealed BCR-ABL fusion transcripts with e19a2 in patient 1 and e191a in patient 2. These findings suggest that
CML
carrying micro-bcr breakpoint may exhibit a similar clinical course to classical
CML
, and that it may not be a mild form of the disease.
...
PMID:Blast crisis of Philadelphia chromosome-positive chronic myeloid leukaemia carrying micro-bcr breakpoint (e19a2 and e191a). 1210 Jan 56
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