Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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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)

Leukemic cells from two patients with Philadelphia-negative chronic myeloid leukemia (CML) were investigated: 1) Cytogenetics showed a normal 46,XY karyotype in both cases, 2) molecular studies revealed rearrangement of the M-BCR region and formation of BCR-ABL fusion mRNA with b2a2 (patient 1) or b3a2 (patient 2) configuration, and 3) fluorescence in situ hybridization (FISH) demonstrated relocation of the 5' BCR sequences from one chromosome 22 to one chromosome 9. The ABL probe hybridized to both chromosomes 9 at band q34, while two other probes which map centromeric and telomeric of BCR on 22q11 hybridized solely with chromosome 22. For the first time, a BCR-ABL rearrangement is shown to take place on 9q34 instead of in the usual location on 22q11. A rearrangement in the latter site is found in all Ph-positive CML and in almost all investigated CML with variant Ph or Ph-negative, BCR-positive cases. The few aberrant chromosomal localizations of BCR-ABL recombinant genes found previously were apparently the result of complex and successive changes. Furthermore in patient 2, both chromosomes 9 showed positive FISH signals with both ABL and BCR probes. Restriction fragment length polymorphism (RFLP) analysis indicated that mitotic recombination had occurred on the long arm of chromosome 9 and that the rearranged chromosome 9 was of paternal origin. The leukemic cells of this patient showed a duplication of the BCR-ABL gene, analogous to duplication of the Ph chromosome in classic CML. In addition they had lost the maternal alleles of the 9q34 chromosomal region.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Translocation of BCR to chromosome 9: a new cytogenetic variant detected by FISH in two Ph-negative, BCR-positive patients with chronic myeloid leukemia. 751 67

The Philadelphia chromosome (Ph) is associated with leukemia, most frequently of the chronic myelogenous variety. The Ph chromosome is a translocation chromosome which gains oncogenic potential through the fusion of the ABL oncogene of chromosome 9 with the BCR gene of chromosome 22. The Ph is believed to arise from random chromosome rearrangement with a subsequent selective advantage of the malignant cell line. However, alleles may be present in the population which predispose toward this specific rearrangement. We used a highly polymorphic CGG-repeat polymorphism within the first exon of the BCR gene to determine BCR allele frequencies among 26 leukemia patients with the Ph chromosome and 63 control individuals. Eight BCR alleles of variable CGG-repeat length were present in both groups at statistically similar frequencies and in Hardy-Weinberg equilibrium. We therefore concluded that there are no alleles of the BCR gene that have a major predisposing influence on the development of the Ph chromosome and subsequent leukemia.
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PMID:CGG-repeat polymorphism of the BCR gene rules out predisposing alleles leading to the Philadelphia chromosome. 751 45

The chimeric BCR/ABL protein is characteristic of Philadelphia (Ph)+ leukemia because it is the direct product of the Ph translocation and it has been shown to play a causal role in the genesis of leukemia. The BCR/ABL protein exhibits a deregulated tyrosine-kinase activity capable of phosphorylating different cellular substrates in vivo and in vitro. CRKL, an adaptor protein consisting of SH2 and SH3 domains in the absence of a catalytic domain, is one potential in vivo substrate of BCR/ABL. Previous experiments have shown that CRKL is phosphorylated on tyrosine in the chronic myelogenous leukemia (CML) cell line K562 and that CRKL is a substrate for ABL and for BCR/ABL in COS-1 cells. In the current study, we show that in peripheral blood cells a direct correlation exists between the presence of BCR/ABL and the phosphorylation status of CRKL. In Ph- peripheral blood cells, CRKL is present only in the nonphosphorylated form. In contrast, all BCR/ABL+ CML and acute lymphoblastic leukemia patient samples examined showed clear tyrosine-phosphorylation of CRKL. This result strongly suggests that CRKL is a biologically significant substrate for BCR/ABL and is likely to play a major role in the development of Ph+ leukemia.
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PMID:Tyrosine phosphorylation of CRKL in Philadelphia+ leukemia. 752 85

We recently reported that interleukin-3, Steel factor, and erythropoietin all induce the tyrosine phosphorylation of Shc and its association with Grb2 in hemopoietic cell lines. We have now further characterized the proteins that become associated with Shc following stimulation with these cytokines and found that, in response to all three, the tyrosine-phosphorylated form of Shc binds to common 145- and 52-kDa proteins which also become tyrosine phosphorylated in response to these growth factors. The 145-kDa protein, which appears, from antiphosphotyrosine blots of two-dimensional O'Farrell gels, to exist in four different phosphorylation states following cytokine stimulation (with isoelectric points ranging from 7.2 to 7.8), does not appear to be immunologically related to the beta subunit of the interleukin-3 receptor, c-Kit, BCR, ABL, JAK1, JAK2, Sos1, eps15, or insulin receptor substrate 1 protein. Silver-stained sodium dodecyl sulfate gels indicate that the association of the 145-kDa protein with Shc occurs only after cytokine stimulation and that it can bind to the tyrosine-phosphorylated form of Shc in its non-tyrosine-phosphorylated state. The latter finding, in conjunction with the observations that p145 does not bind, in vitro, to the Src homology 2 (SH2) domain of Shc, that it is not present in anti-Grb2 immunoprecipitates, and that a phosphopeptide which blocks the binding of Shc to the SH2 domain of Grb2 also blocks the binding of Shc to p145, suggests that p145 contains an SH2 domain and competes with Grb2 for the same tyrosine-phosphorylated site on Shc. This implicates p145 as a potential regulator of Ras activity and, perhaps, of other as yet unidentified functions of Shc.
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PMID:Multiple cytokines stimulate the binding of a common 145-kilodalton protein to Shc at the Grb2 recognition site of Shc. 752 59

The mechanisms of the chronic myeloid leukemia (CML) clones proliferative advantage over normal clones are currently unknown. They may involve an insensitivity to a negative regulation of a growth factor-independent proliferation. Clonogenic progenitors from CML patient blood or marrow in chronic phase were grown either in the presence or absence of recombinant growth factors. No erythroid colonies were observed in the absence of any cytokine. In contrast, erythroid colonies composed of fully mature hemoglobinized erythroblasts (day 12 burst-forming units-erythroid) were obtained in the presence of Steel factor (SF) alone. Addition of erythropoietin (Epo) to SF either had no effect on the cloning efficiency or increased up to 50% the number of erythroid colonies. No erythroid growth was observed when cultures were stimulated by interleukin-3 or granulocyte-macrophage colony-stimulating factor alone. Similar erythroid growth in the presence of SF but without Epo was obtained in "serum-free" cultures when purified blood CML CD34+ cells were grown. This growth of erythroid colonies in the absence of Epo was not accounted for by an autocrine stimulation loop by Epo, because neutralizing antibodies against Epo did not inhibit it. This abnormal response to growth factor was specifically observed in the CML clone, as shown by the presence of the BCR-ABL transcript in all of these erythroid colonies. The direct implication of BCR-ABL was further documented (1) by studies of alpha-interferon-treated patients with a chimerism in which the abnormal growth correlates with the presence of the malignant clone and (2) by the use of antisense oligonucleotide against BCR-ABL transcript, which abrogated this abnormal growth. Finally, erythroid growth in the SF presence was greatly diminished by herbimycin A, whereas, at the same concentration, this tyrosine kinase inhibitor had no marked effect on erythroid colony formation in the presence of SF plus Epo on CML or normal marrow cells. This result suggests that the BCR-ABL kinase activity leads directly to this Epo-independent terminal differentiation requiring, however, the presence of SF.
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PMID:Growth of erythroid colonies in chronic myelogenous leukemia is independent of erythropoietin only in the presence of steel factor. 752 39

In the ongoing trial ALL-BFM 90 for the treatment of childhood non-B cell acute lymphoblastic leukemia (ALL) 1468 unselected patients (pts) were enrolled from 84 centers in Germany and Switzerland from 4/90 to 12/93. Based on the results of the previous trial ALL/NHL-BFM 86 this treatment program focused especially on therapy modifications for average (MRG) and high risk (HRG) pts, on the evaluation of therapy response for prognosis, and on the identification of high risk pts by molecular genetics. For average risk pts consolidation therapy was intensified by the addition of L-asparaginase (L-ASP) on a randomized basis. In HRG induction and consolidation therapy was modified by introduction of early intensification elements that had proved to be effective in relapsed pts. This patient group was randomized for the evaluation of the effects of G-CSF administered in the intervals between the intensification elements. Distribution of the 1376 eligible pts into the three treatment arms SRG (standard risk), MRG, and HRG was as expected (17 pts not yet assigned): 385 pts (28.0%), 834 pts (60.6%), and 140 pts (10.2%), respectively. Treatment consisted of the 8-drug induction (Protocol I), consolidation (Protocol M), reinduction (Protocol II), and maintenance therapy (total therapy duration 24 months). The drug doses and combinations were only slightly modified compared to the previous study ALL-BFM 86 with the exception of the randomized L-ASP containing arm MRG-2 (Protocol M-A) and group HRG. Preventive cranial irradiation was reduced to 12 Gy and applied to MRG and HRG pts only. As in study ALL-BFM 86, the initial response to a 7-day exposure to prednisone and to the first intrathecal injection of MTX at diagnosis was evaluated at day 8 of treatment with regard to blast count in peripheral blood (PB). In addition, pts were now investigated for the presence of blasts in the bone marrow (BM) at day 15 of treatment to compare the prognostic power of both response parameters. Identification of translocation t(9; 22) and/or BCR-ABL rearrangement characterized a small subgroup of pts that were not detected by poor initial therapy response. These pts were enrolled in HRG for more intensive treatment including allogeneic bone marrow transplantation (BMT). After a median observation time of 22 months, the overall probability for event-free survival (p-EFS) is 82 +/- 2%. 11 pts (0.8%) died before complete remission (CR) was achieved, 15 pts (1.1%) died while in CR for reasons other than relapse.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Concept and interim result of the ALL-BFM 90 therapy study in treatment of acute lymphoblastic leukemia in children and adolescents: the significance of initial therapy response in blood and bone marrow]. 752 27

The human bcr gene encodes a protein with serine/threonine kinase activity, CDC24/dbl homology, a GAP domain, and an SH2-binding region. However, the precise physiological functions of BCR are unknown. Coexpression of BCR with the cytoplasmic protein-tyrosine kinase encoded by the c-fes proto-oncogene in Sf-9 cells resulted in stable BCR-FES protein complex formation and tyrosine phosphorylation of BCR. Association involves the SH2 domain of FES and a novel binding domain localized to the first 347 amino acids of the FES N-terminal region. Deletion of the homologous N-terminal BCR-binding domain from v-fps, a fes-related transforming oncogene, abolished transforming activity and tyrosine phosphorylation of BCR in vivo. Tyrosine phosphorylation of BCR in v-fps-transformed cells induced its association with GRB-2/SOS, the RAS guanine nucleotide exchange factor complex. These data provide evidence that BCR couples the cytoplasmic protein-tyrosine kinase and RAS signaling pathways.
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PMID:Tyrosine phosphorylation of BCR by FPS/FES protein-tyrosine kinases induces association of BCR with GRB-2/SOS. 752 74

Vav is a recently described proto-oncogene expressed only in hematopoietic cells which contains an SH2 and two SH3 domains and shares homology with the Dbl GDP-GTP exchange factor and BCR. p95Vav is phosphorylated on tyrosine residues in response to stimulation of the T cell antigen receptor, cross-linking of IgE or IgM receptors and stimulation of immature hematopoietic cells by Steel factor. Monoclonal antibodies to human Vav were generated and used to examine the events which regulate tyrosine phosphorylation of p95Vav in myeloid cells. In the factor-dependent MO7e cell line, p95Vav was rapidly phosphorylated on tyrosine residues in a dose- and time-dependent manner by GM-CSF, IL-3 and Steel factor. Introduction of the BCR/ABL oncogene into this cell line resulted in factor-independent proliferation and constitutive phosphorylation of p95Vav. Tyrosine phosphorylation of p95Vav was also substantially increased by treatment of cytokine-deprived cells with the tyrosine phosphatase inhibitor sodium vanadate. Since many of the cytokines known to induce tyrosine phosphorylation of p95Vav are also known to activate JAK family tyrosine kinases, we looked for an interaction of p95Vav with JAK kinases. p95Vav co-precipitated with JAK2 in MO7e cells stimulated with GM-CSF, but not in unstimulated cells. Also, JAK2 was found to be constitutively associated with p95Vav in vivo when expressed at high levels in insect cells using baculovirus vectors. A fusion protein consisting of glutathione-S-transferase and the SH2 domain of p95Vav (GST-Vav-SH2) precipitated JAK2, suggesting that this interaction is mediated by the SH2 domain of p95Vav.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Tyrosine phosphorylation of p95Vav in myeloid cells is regulated by GM-CSF, IL-3 and steel factor and is constitutively increased by p210BCR/ABL. 749 7

We have sought to define the relationship between the proportion of marrow metaphases showing the Philadelphia chromosome (Ph) and levels of BCR-ABL mRNA assessed by quantitative polymerase chain reaction (PCR) in patients with chronic myeloid leukaemia (CML). From a total of 141 patients, 164 PCR assays were performed on peripheral blood samples taken within 2 weeks of a bone marrow specimen analysed by cytogenetics. BCR-ABL mRNA was quantified in all 106 PCR-positive samples by competitive PCR; results ranged from < 10 to 3.4 x 10(6) transcripts/micrograms RNA. Twenty-one chronic-phase patients had a median of 5.0 x 10(5) BCR-ABL transcripts/micrograms RNA; no difference in levels of the fusion mRNA was found between 15 Ph-positive and six Ph-negative, BCR-ABL-positive patients. Ph-positive metaphases were not detected in any individual who was PCR negative (n = 58) and in only a single patient who was PCR positive with < 10(3) BCR-ABL transcripts/micrograms RNA (n = 44). Conversely, of 41 samples from patients in haematological remission who had > 10(3) BCR-ABL transcripts/micrograms RNA, 30 had at least one Ph-positive metaphase. The highest level of BCR-ABL transcripts at which Ph-positive metaphases were not detected was 1.5 x 10(4). For the 46 patients who had at least one Ph-positive metaphase, a good correlation (Spearman coefficient = 0.83, P < 0.0001) was found between the percentage of Ph-positive metaphases and BCR-ABL transcript levels.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Correlation between the proportion of Philadelphia chromosome-positive metaphase cells and levels of BCR-ABL mRNA in chronic myeloid leukaemia. 754 5

A reciprocal translocation, t(10;22)(q22;q11), resulting in a masked Ph chromosome was identified in a patient diagnosed with chronic myeloid leukemia (CML). Both homologs of chromosome 9 were of the normal pattern. Two signals for the ABL probe, both of them hybridized to chromosome 9, were demonstrated via fluorescence in situ hybridization (FISH). Furthermore, cohybridization with two differently labeled BCR/ABL translocation DNA probes indicated a BCR/ABL fusion apparently located on 9q34. Molecular studies revealed a rearrangement of the BCR region and expression of a chimeric BCR/ABL mRNA of CML configuration. These findings indicate that the BCR/ABL fusion resulted from an unusual relocation of the BCR gene from its normal position on 22q11 to 9q34 adjacent to the ABL gene.
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PMID:BCR/ABL fusion located on chromosome 9 in chronic myeloid leukemia with a masked Ph chromosome. 754 8


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