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)

A novel variant of the chimeric BCR-ABL mRNA transcript was detected in a patient with Philadelphia chromosome-negative (Ph-) chronic myelogenous leukemia (CML) by multiplex reverse-transcription polymerase chain reaction (RT-PCR). Sequence analysis of the fusion region of the amplified cDNA fragment showed an in-frame joining of exon e6 of the BCR gene and exon a2 of the ABL gene, giving rise to an e6a2 BCR-ABL transcript. This finding was confirmed by Southern blot analysis using a specific probe corresponding to intron 6 of the BCR gene, whereas conventional Southern blot for rearrangement of the major breakpoint cluster region (M-bcr) was negative. Western blot studies detected a BCR-ABL protein slightly larger than p185 BCR-ABL. Metaphase fluorescence in situ hybridization showed an insertion of ABL material into the BCR region without reciprocal BCR translocation. The findings in this case show that atypical BCR-ABL transcripts are detectable even in Ph- CML patients without M-bcr-rearrangements. Multiplex PCR using primers that allow for amplification of all known BCR-ABL transcripts is an appropriate method to exclude these rare variants.
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PMID:A novel BCR-ABL fusion gene (e6a2) in a patient with Philadelphia chromosome-negative chronic myelogenous leukemia. 882 44

Prolactin (PRL) has been demonstrated to induce tyrosine phosphorylation and activation of the cytoplasmic tyrosine kinase JAK2. The present study represents an initial effort to identify the phosphorylation repertoire of the PRL receptor (PRLR). For this purpose we have modified the rat PRLR cDNA to encode an additional N-terminal epitope specifically designed to allow the rapid purification of the PRLR and associated proteins from transfected cells. The Flag-tagged PRLR was stably expressed in the human 293 cell line. PRL induced tyrosine phosphorylation of proteins of 85, 95, and 185 kDa from 10 to 30 min after PRL stimulation. Immunoblot analysis of immunoprecipitation indicates that p85 corresponds to the 85-kDa regulatory subunit of phosphatidylinositol (PI)-3' kinase, p95 to PRLR, and p185 to insulin receptor substrate 1 (IRS-1). Both PI-3' kinase and IRS-1 appear to associate with PRLR in a PRL-dependent manner. These results thus indicate that kinases other than JAK2, namely PI-3' kinase, are activated by PRL.
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PMID:Prolactin activates tyrosyl phosphorylation of insulin receptor substrate 1 and phosphatidylinositol-3-OH kinase. 899

The characterization of novel cytoplasmic, structural, and enzymatic proteins has been enhanced by a panel of monoclonal antibodies specific for protein substrates of transforming and nontransforming c-Src mutants. These protein substrates have included the focal adhesion kinase (FAK), cortactin, AFAP-110, p120CAS, and p130CAS. The monoclonal antibody 4G8 was generated as part of this panel of antibodies and was used to isolate the human gene for a 167-kD polypeptide. The cDNA sequence is 5,238 nucleotides in length with a predicted open reading frame consisting of 1,382 amino acids. The polypeptide is largely hydrophilic and highly charged. The central region of p167 has 88% identity with the entire 278-amino-acid encoded sequence of the murine centrosomin A gene. The carboxyl third of p167 contains a unique cluster of 10 amino acid repeats with the consensus sequence (A/M)DDDRGPRRG. The p167 protein was found primarily in the cytoplasm of lymphocytes and is part of a multicomponent protein complex with prominent members of 167, 120, 64, 45, 40, 38, and 25 kD. Finally, we illustrate the conservation of p167 and its associated complex, and demonstrate its expression in different human tissues and cell types. The data suggest that p167 is novel and has an important cellular function as a cytoplasmic structural protein.
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PMID:The human p167 gene encodes a unique structural protein that contains centrosomin A homology and associates with a multicomponent complex. 915 Apr 39

We examined the potential of generating an immune response against Philadelphia chromosome-positive acute lymphoblastic leukemia. The immunostimulatory molecules chosen for this study were the cytokines IL-2 and GM-CSF and the costimulatory ligand CD80 (B7.1). We used a murine model based on a BALB/c pre-B cell line, BM185wt, in which leukemia is induced by the p185 BCR-ABL oncogenic product, which reproduces Philadelphia chromosome-positive ALL. BM185wt cells were transduced with retroviral vectors and the transduced clones expressing mIL-2, mGM-CSF, or mCD80 were used for challenge. Expression of the immunomodulators by BM185 cells was correlated with delay in leukemia development in immunocompetent mice, but not in immunodeficient mice, indicating an immune response against the modified leukemia cells. Expression of CD80 caused leukemia rejection in 50% of the cohort, which was associated with the CD4+ and CD8+ T cell-dependent development of anti-leukemia cytotoxic T lymphocytes. Furthermore, mice surviving the BM185/CD80 challenge or preimmunized with irradiated BM185/CD80 cells developed an immune response against subsequent challenge with the parental leukemia. These studies provide evidence that immunotherapeutic approaches can be developed for the treatment of ALL.
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PMID:Immune response to Philadelphia chromosome-positive acute lymphoblastic leukemia induced by expression of CD80, interleukin 2, and granulocyte-macrophage colony-stimulating factor. 975 32

The factor-independent Dami/HEL and Meg-01 and factor-dependent Mo7e leukemic cell lines were used as models to investigate JAK/STAT signal transduction pathways in leukemic cell proliferation. Although Dami/HEL and Meg-01 cell proliferation in vitro was independent of and unresponsive to exogenous cytokines including granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), IL-6, thrombopoietin (TPO), and tumor necrosis factor-alpha (TNF-alpha), the growth of Mo7e cells was dependent on hematopoietic growth factors. When these cell lines were cultured in medium without cytokines, a constitutively activated STAT-like DNA-binding factor was detected in nuclear extracts from both Dami/HEL and Meg-01 cells. However, the STAT-like factor was not detectable in untreated Mo7e cells, but was activated transiently in Mo7e cells in response to cytokine treatments. The constitutively activated and cytokine-induced STAT-like DNA-binding factor in these three cell lines was identified as STAT5 by oligonucleotide competition gel mobility assays and by specific anti-STAT antibody gel supershift assays. Constitutive activation of JAK2 also was detected in the factor-independent cell lines, but not in Mo7e cells without cytokine exposure. Meg-01 cells express a p185 BCR/ABL oncogene, which may be responsible for the constitutive activation of STAT5. Dami/HEL cells do not express the BCR/ABL oncogene, but increased constitutive phosphorylation of Raf-1 oncoprotein was detected. In cytokine bioassays using growth factor-dependent Mo7e and TF-1 cells as targets, conditioned media from Dami/HEL and Meg-01 cells did not show stimulatory effects on cell proliferation. Our results indicate that the constitutive activation of JAK2/STAT5 correlates with the factor-independent growth of Dami/HEL and Meg-01 cells. The constitutive activation of JAK2/STAT5 in Dami/HEL cells is triggered by a mechanism other than autocrine cytokines or the BCR/ABL oncoprotein.
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PMID:Constitutive activation of the JAK2/STAT5 signal transduction pathway correlates with growth factor independence of megakaryocytic leukemic cell lines. 1009 Sep 48

CGP 57148 is a potent inhibitor of the ABL protein tyrosine kinase and a promising new compound for the treatment of a variety of BCR-ABL-positive leukemias. We used this enzyme inhibitor to characterize the biological effects of BCR-ABL in primary cells and two growth factor-dependent BCR-ABL-transfected cell lines. The effect of CGP 57148 on primary cells is dependent on the stage of differentiation. The growth of maturing chronic myeloid leukemia cells is independent of BCR-ABL in the presence of growth factors. However, the proliferation of leukemic immature cobblestone-forming area cells is almost completely blocked after the inhibition of the BCR-ABL kinase. In the BCR-ABL-transfected cell lines, M07/ p210 and Ba/F3/p185, CGP 57148 induces apoptosis by releasing cytochrome c, activating caspase 3, and cleavage of PARP. No alteration of the expression level of the apoptosis regulator BCL-2 was observed. In contrast, BCL-X was down-regulated after exposure to CGP 57148. Inhibitors of signal transduction proteins such as PI-3 kinase, mitogen-activated protein/extracellular signal-regulated kinase kinase, and Janus-activated kinase 2 pathways were not capable of a comparable down-regulation of BCL-X. The Fas/Fas ligand system was not involved either in the induction of apoptosis by CGP 57148. We conclude that the inhibition of the BCR-ABL kinase by CGP 57148 (a) preferentially inhibits the growth of immature leukemic precursor cells, (b) efficiently reverts the antiapoptotic effects of BCR-ABL by down-regulation of BCL-X, and (c) is more effective than the inhibition of the downstream signal transduction pathways of PI-3 kinase, mitogen-activated protein/extracellular signal-regulated kinase kinase, and Janus-activated kinase 2.
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PMID:The tyrosine kinase inhibitor CGP 57148 (ST1 571) induces apoptosis in BCR-ABL-positive cells by down-regulating BCL-X. 1081 21

Using human acute leukemia HL-60/Bcr-Abl (with ectopic expression of p185 Bcr-Abl) and K562 cells (with endogenous expression of p210 Bcr-Abl) subjected to a continuous selection pressure of up to 1.0 micro M Gleevec (imatinib mesylate, STI-571), we have isolated Gleevec-resistant K562 R (+Bcr-Abl), K562 R (-Bcr-Abl), and HL-60/Bcr-Abl R cells, which display disparate level and activity of Bcr-Abl tyrosine kinase (TK). As compared with their sensitive counterparts, Gleevec-resistant cell types were >/=5-fold resistant to Gleevec-induced apoptosis. Bcr-Abl protein levels were significantly increased in HL-60/Bcr-Abl R and K562 R (+Bcr-Abl) cells, but K562 R (-Bcr-Abl) cells showed a marked decline in the mRNA and protein levels and activity of Bcr-Abl. Bcr-Abl TK level and activity corresponded to the signal transducers and activators of transcription-5 DNA binding activity and up-regulation of heat shock protein 70 levels. The decline in Bcr-Abl expression and TK activity in K562 R (-Bcr-Abl) cells was associated with reduced AKT kinase and signal transducers and activators of transcription-5 DNA binding activities and increased sensitivity to the death ligand Apo-2 ligand/tumor necrosis factor-related apoptosis-inducing ligand and 1-beta-D-arabinofuranosylcytosine-induced apoptosis. All Gleevec-resistant cell types were sensitive to 17-allylamino-17-demethoxygeldanamycin (17-AAG)- and PD180970 (a SRC and Bcr-Abl TK inhibitor)-induced apoptosis. Treatment with 17-AAG or PD180970 also induced apoptosis of CD34+ leukemic cells from three patients with chronic myeloid leukemia in blast crisis who had progressive leukemia while receiving Gleevec therapy. Taken together, these findings indicate that in addition to overexpression or mutations in Bcr-Abl, resistance to Gleevec may also develop due to a loss of Bcr-Abl expression. These findings also support the rationale to test the in vivo efficacy of 17-AAG and PD180970 against STI-571-resistant Bcr-Abl-positive acute leukemias.
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PMID:Molecular characterization and sensitivity of STI-571 (imatinib mesylate, Gleevec)-resistant, Bcr-Abl-positive, human acute leukemia cells to SRC kinase inhibitor PD180970 and 17-allylamino-17-demethoxygeldanamycin. 1238 36

Translocations involving the abl locus on chromosome 9 fuses the tyrosine kinase c-ABL to proteins harboring oligomerization interfaces such as BCR or TEL, enabling these ABL-fusion proteins (X-ABL) to transform cells and to induce leukemia. The ABL kinase activity is blocked by the ABL kinase inhibitor STI571 which abrogates transformation by X-ABL. To investigate the role of oligomerization for the transformation potential of X-ABL and for the sensitivity to STI571, we constructed ABL chimeras with oligomerization interfaces of proteins involved in leukemia-associated translocations such as BCR, TEL, PML, and PLZF. We assessed the capacity of these chimeras to form high molecular weight (HMW) complexes as compared with p185(BCR-ABL). There was a direct relationship between the size of HMW complexes formed by these chimeras and their capacity to induce factor independence in Ba/F3 cells, whereas there was an inverse relationship between the size of the HMW complexes and the sensitivity to STI571. The targeting of the oligomerization interface of p185(BCR-ABL) by a peptide representing the coiled coil region of BCR reduced its potential to transform fibroblasts and increased sensitivity to STI571. Our results indicate that targeting of the oligomerization interfaces of the X-ABL enhances the effects of STI571 in the treatment of leukemia caused by X-ABL.
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PMID:Targeting of the N-terminal coiled coil oligomerization interface of BCR interferes with the transformation potential of BCR-ABL and increases sensitivity to STI571. 1282 85

Chronic myelogenous leukemia (CML) results from a t(9,22) translocation, producing the p210(BCR-ABL) oncoprotein, a tyrosine kinase that causes transformation and chemotherapy resistance. To further understand mechanisms mediating chemotherapy resistance, we identified 556 differentially regulated genes in HL-60 cells stably expressing p210(BCR-ABL) versus those expressing an empty vector using cDNA macro- and oligonucleotide microarrays. These BCR-ABL-regulated gene products play diverse roles in cellular function including apoptosis, cell cycle regulation, intracellular signaling, transcription, and cellular adhesion. In particular, we identified up-regulation of the inducible form of heat shock protein 70 (Hsp70), and further explored the mechanism for its up-regulation. In HL-60/BCR-ABL and K562 cells (expressing p210(BCR-ABL)), abundant cytoplasmic Hsp70 expression was detected by immunoblot analysis. Moreover, cells isolated from bone marrow aspirates of patients in different stages of CML (chronic, aggressive, and blast crisis) express Hsp70. Expression of p210(BCR-ABL) in BCR-ABL negative cells induced transcription of the proximal Hsp70 promoter. Mutational analysis mapped the major p210(BCR-ABL) responsive element to a high affinity 5'(A/T)GATA(A/G)-3' "GATA" response element (GATA-RE) that binds GATA-1 in CML cells. The GATA-RE was sufficient to confer p210(BCR-ABL)- and p185(BCR-ABL)-mediated trans-activation to an inert promoter. Short interfering RNA mediated "knockdown" of Hsp70 expression in K562 cells induced marked sensitivity to paclitaxel-induced apoptosis. Together these findings indicate that BCR-ABL confers chemotherapeutic resistance through intracellular signaling to the GATA-RE element found in the promoter region of the anti-apoptotic Hsp70 protein. We suggest that down-regulation of the GATA-Hsp70 pathway may be useful in the treatment of chemotherapy-resistant CML.
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PMID:Genomic mechanisms of p210BCR-ABL signaling: induction of heat shock protein 70 through the GATA response element confers resistance to paclitaxel-induced apoptosis. 1515 49

Most patients with Philadelphia (Ph)-positive acute lymphoblastic leukemia (ALL) show evidence of secondary chromosome aberrations that may influence the course of disease and response to treatment. To better understand how these secondary chromosomal aberrations occur and to investigate whether the p185/p190 BCR-ABL fusion protein may directly induce an increased chromosomal instability and subsequently the appearance of clonal chromosome aberrations, three BRC-ABL (p185/ p190)-transduced mouse pre-B cell lines were analyzed by spectral karyotyping and fluorescence in situ hybridization. The human wild-type BCR-ABL gene was expressed at a level comparable with that in human Ph-positive leukemias at diagnosis. All BCR-ABL-transduced cell lines acquired similar clonal chromosomal aberrations. Trisomy 5 was always present, followed by loss of the Y chromosome, trisomy of chromosomes 12 and 18, and an unbalanced translocation between chromosomes X and 12. Thus, ectopic p185/p190 BCR-ABL expression, such as p210 BCR-ABL, PML-RARA, or C-MYC transduction, may induce an increased chromosomal instability leading to clonal karyotypic evolution, which may mimic secondary chromosome aberrations in human Ph-positive ALL.
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PMID:Cytogenetic characterization of a BCR-ABL transduced mouse cell line. 1608 Sep 57


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