Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.10.2 (focal adhesion kinase)
 44,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Constitutive activation of BCR-ABL tyrosine kinase fusion protein has been shown to be an essential step in the pathogenesis of Philadelphia chromosome (Ph)-positive leukemias. We studied the tyrosine phosphorylated proteins which might be involved in the signaling pathway p185BCR-ABL using a Ph-positive acute lymphoblastic leukemia cell line. p185BCR-ABL but not p145c-abl was constitutively phosphorylated on tyrosine in this cell line. p21ras GTPase-activating protein (GAP) was physically associated with p185BCR-ABL, but not with p145c-abl, and GAP-associated proteins p62/p190 were found to be tyrosine-phosphorylated. Furthermore, p185BCR-ABL was also physically associated with phospholipase C-gamma 1 (PLC-gamma) and phosphatidylinositol 3'-kinase (P13-kinase). Concomitantly, both PLC-gamma and p85 subunit of P13-kinase are tyrosine-phosphorylated in the cells with p185BCR-ABL. These data suggest that GAP, GAP-associated proteins, PLC-gamma, and P13-kinase may participate in downstream signaling for p185BCR-ABL tyrosine kinase.
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PMID:Potential molecules implicated in downstream signaling pathways of p185BCR-ABL in Ph+ ALL involve GTPase-activating protein, phospholipase C-gamma 1, and phosphatidylinositol 3'-kinase. 828 76

A double Philadelphia chromosome (Ph)-positive leukemia cell line with common-B cell phenotype, designated TMD5, was established from the blast cells of a patient with double Ph-positive acute lymphoblastic leukemia. TMD5 cells expressed 190 kDa BCR/ABL chimeric protein and 145 kDa ABL protein. The cells proliferated without added growth factors. Autocrine growth mechanism was not recognized. The addition of growth factors such as G-CSF, GM-CSF, IL-3, IL-6, or Stem Cell Factor did not affect the growth. Herbimycin A suppressed the growth of TMD5 cells at the low concentration that did not affect Ph-negative cells. It suppressed tyrosine phosphorylation of intracellular proteins in TMD5 cells. Dexamethasone and dibutyryl cyclic AMP also suppressed the growth. They, however, did not affect the phosphorylation significantly. Neither all-trans retinoic acid nor interferon-alpha affected the growth. TMD5 cells, characterized minutely here and rare in that they have double Ph chromosomes, will be a useful tool for the study of Ph-positive leukemia.
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PMID:Establishment of a double Philadelphia chromosome-positive acute lymphoblastic leukemia-derived cell line, TMD5: effects of cytokines and differentiation inducers on growth of the cells. 1007 Oct 78

In human Ph-positive leukemia there is a clear association of different forms of the BCR-ABL oncogene with distinct types of leukemia. The P190 form of BCR-ABL is rarely observed in chronic myeloid leukemia (CML) but is present in 50% of Ph-positive acute lymphoblastic leukemia (ALL). In contrast, the P210 form is observed both in CML and 50% of Ph-positive ALL. Methylation of the proximal promoter of the ABL1 gene has been shown to be a nearly universal event associated with clinical progression of CML. This raises the question of whether methylation of the ABL1 promoter is an epigenetic modification also associated with Ph-positive ALL. To study this issue, we used methylation-specific PCR and bisulfite sequencing to determine the methylation status of the ABL1 promoter in 18 Ph-positive ALL samples. We report here that gene-specific ABL1 promoter methylation is associated mainly with the P210 form of BCR-ABL and not the P190 form. While six out of the seven P210-positive ALL samples had ABL1 promoter methylation, none of the 11 P190-positive ALL samples demonstrated ABL1 promoter methylation. In addition, we estimated the extent and relative abundance of ABL1 promoter methylation in several Ph-positive ALL samples and compared it to the methylation pattern in chronic, accelerated and blastic crisis phases of CML. We put forth a model that correlates the different types of leukemias with the different levels of ABL1 promoter methylation.
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PMID:ABL1 methylation in Ph-positive ALL is exclusively associated with the P210 form of BCR-ABL. 1136 59

Imatinib, a specific inhibitor of the Abl, Kit and platelet-derived growth factor receptor (PDGFR) tyrosine kinases, is effective in all phases of chronic myelogenous leukemia. While responses in chronic phase are usually durable, resistance frequently develops in patients with advanced disease after an initial response. Several mechanisms of resistance have been demonstrated in vivo, including mutations in the BCR-ABL kinase domain and amplification of the BCR-ABL gene. We analyzed cytogenetics and screened for mutations of the BCR-ABL kinase domain as well as the activation loops of KIT and PDGFRA and B in 49 patients with CML or Ph-positive acute lymphoblastic leukemia with resistance to imatinib. Mutations in the kinase domain of BCR-ABL were detected in 51.6% of patients with secondary resistance but not in patients with primary resistance. Three of these mutations have not been described before (T315D, F359D and D276G). By contrast, KIT and PDGFRA and B were consistently wildtype. Clonal evolution prior to imatinib was present in 68.8% of patients with primary resistance and in 45.5% with secondary resistance. Additional cytogenetic aberrations developed in 18.2% of patients at the time of relapse. Our results confirm the high frequency of BCR-ABL kinase domain mutations in patients with secondary resistance to imatinib and exclude mutations of the activation loops of KIT, PDGFRA and PDGFRB as possible causes of resistance in patients without ABL mutations.
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PMID:High incidence of BCR-ABL kinase domain mutations and absence of mutations of the PDGFR and KIT activation loops in CML patients with secondary resistance to imatinib. 1474 31

The BCR/ABL tyrosine kinase inhibitor, imatinib mesylate, has shown substantial effects in chronic myelogenous leukemia (CML) and Ph-positive acute lymphoblastic leukemia (Ph(+)ALL). However, most patients relapse after an initial clinical response, indicating that drug resistance is a major problem in patients on imatinib. It is a serious problem that effective treatment choices to T315I, in the ABL kinase domain that shows a strong tolerance in imatinib do not exist clinically. In this study, we propose a new therapeutic approach to Ph(+)ALL with the T315I. Here, we report that the serine/threonine kinase mTOR (the mammalian target of rapamycin) inhibitor, rapamycin, inhibits the growth of not only the Bcr-Abl-positive lymphoid leukemic cell line, SU-Ph2, established from Ph(+)ALL patients, but also the imatinib-resistant cell line, SU/SR, that has acquired T315I. Rapamycin significantly inhibits cell growth in both these cell lines, and easily induces apoptosis at the same dose, thereby acting as an immunosuppressive agent. Our result suggested that the mTOR-signaling pathway has become an important therapeutic target for Ph-positive leukemias in the future, and at the same time, it is also becoming a very effective tool for the treatment of Ph(+)ALL with T315I.
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PMID:Hypersensitivity of Ph-positive lymphoid cell lines to rapamycin: Possible clinical application of mTOR inhibitor. 1878 28

In Ph-positive leukemia, imatinib brought marked clinical improvement; however, further improvement is needed to prevent relapse. Cancer cells efficiently use limited energy sources, and drugs targeting cellular metabolism improve the efficacy of therapy. In this study, we characterized the effects of novel anti-cancer fatty-acid derivative AIC-47 and imatinib, focusing on cancer-specific energy metabolism in chronic myeloid leukemia cells. AIC-47 and imatinib in combination exhibited a significant synergic cytotoxicity. Imatinib inhibited only the phosphorylation of BCR-ABL; whereas AIC-47 suppressed the expression of the protein itself. Both AIC-47 and imatinib modulated the expression of pyruvate kinase M (PKM) isoforms from PKM2 to PKM1 through the down-regulation of polypyrimidine tract-binding protein 1 (PTBP1). PTBP1 functions as alternative splicing repressor of PKM1, resulting in expression of PKM2, which is an inactive form of pyruvate kinase for the last step of glycolysis. Although inactivation of BCR-ABL by imatinib strongly suppressed glycolysis, compensatory fatty-acid oxidation (FAO) activation supported glucose-independent cell survival by up-regulating CPT1C, the rate-limiting FAO enzyme. In contrast, AIC-47 inhibited the expression of CPT1C and directly fatty-acid metabolism. These findings were also observed in the CD34(+) fraction of Ph-positive acute lymphoblastic leukemia cells. These results suggest that AIC-47 in combination with imatinib strengthened the attack on cancer energy metabolism, in terms of both glycolysis and compensatory activation of FAO.
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PMID:Perturbation of energy metabolism by fatty-acid derivative AIC-47 and imatinib in BCR-ABL-harboring leukemic cells. 2660 3