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)

The IL-3 and GM-CSF (hGMR) receptors consist of two subunits, alpha and beta, both of which are members of the cytokine receptor superfamily. Phosphorylation of tyrosine residues of hGMR beta subunit and several cellular proteins are observed with hGM-CSF stimulation. We analyzed role of tyrosine residue of hGMR beta subunit and nature of tyrosine kinase, JAK2 in hGMR signals using several hGMR beta subunit mutants. In addition to box1 region, a membrane distal region (a.a. 544-589) of hGMR beta is required for c-fos activation. Only one tyrosine residue (Tyr577) exists within the region 544-589, and substitution of Tyr577 to phenylalanine in GMR beta 589 resulted in the loss of c-fos activation. In contrast, the same substitution in a wild type receptor did not affect GM-CSF-induced activities such as c-fos mRNA induction and proliferation but abolished Shc phosphorylation. These results suggest that the activation of Shc is not essential for c-fos activation and several tyrosine residues co-ordinate to activate c-fos activation. It is well documented that IL-3 or GM-CSF activates JAK2 in BA/F3 cells. However the role of JAK2 in IL-3/GM-CSF functions is largely unknown. We examined the role of JAK2 in GM-CSF-induced signaling pathways. Dominant negative JAK2 (delta JAK2) lacking the C-terminus kinase domain, suppressed IL-3/GM-CSF induced c-fos activation, c-myc activation and proliferation suggesting that JAK2 is involved in both signaling pathways. PTP1D and Shc are phosphorylated by IL-3/GM-CSF in BA/F3 cells, however these phosphorylation events were inhibited by expression of delta JAK2. Taken together, these results indicate that JAK2 is a primary kinase regulating all the known activities of GM-CSF. JAK2 mediates GM-CSF induced c-fos activation through receptor phosphorylation and Shc/PTP1D activation.
Leukemia 1997 Apr
PMID:Roles of JAK kinase in human GM-CSF receptor signals. 920 4

Friend leukemia virus complex (FLV) consists of replication-defective, Friend spleen focus-forming virus (F-SFFV) and replication-competent, Friend murine leukemia virus (F-MuLV). We produced transgenic mice possessing F-SFFV gp55 gene and clarified that the gp55 glycoprotein encoded by F-SFFV env-related gene is, by itself, responsible for the initiation of erythroleukemia. The occurrence of erythroleukemia, however, is sporadic in these mice. Erythroleukemia cell lines established from these mice possessed mutations in the p53 allele. One had a temperature-sensitive mutant p53 allele, p53Val-135 and showed induction of apoptosis by expressing a wild-type p53 protein at 32 degrees C. Superinfection of the mice with Moloney murine leukemia virus (Mo-MuLV) conferred 100% induction of erythroleukemia, mutating p53 gene or activating Spfi-1 gene by insertional events. Activation of the JAK/STAT pathway, which is involved in cytokine signaling, was investigated in the gp55 signaling mediated by the erythropoietin receptor. JAK1 and STAT5 were constitutively tyrosine-phosphorylated but the DNA binding activity of STAT5 was not induced.
Leukemia 1997 Apr
PMID:Pathogenesis of Friend leukemia virus. 920 27

Friend spleen focus forming-virus (F-SFFV) induces acute erythroleukemia in susceptible mice. Initiation of the erythroleukemia is due to binding of the env-related glycoprotein gp55 encoded by F-SFFV to the erythropoietin receptor (EPOR). The gp55/EPOR interaction induces prolonged and growth factor independent proliferation in a factor-dependent cell line. In erythropoietin (EPO) signaling, the JAK2/STAT5 pathway was shown to be activated downstream of the EPOR to transmit the signal to the cells. To determine members of the JAK family and the STAT transcription factor family involved in the gp55/EPOR signaling, we examined tyrosine phosphorylation of JAKs and STATs in F-SFFV-infected erythroid or erythroleukemic cells. JAK1 and STAT5 were constitutively tyrosine-phosphorylated but the DNA binding activity of STAT5 was not induced without EPO stimulation in erythroblastoid cells from spleens of F-SFFV-infected mice and erythroleukemia cell lines derived from gp55-transgenic mice. These results indicate that JAK1 is involved in the gp55/EPOR signaling but STAT5 is not playing an essential role in the growth of those erythroid cells.
Leukemia 1997 Apr
PMID:Activation of the JAK1-STAT5 pathway by binding of the Friend virus gp55 glycoprotein to the erythropoietin receptor. 920 15

Thrombopoietin (Tpo) is a cytokine which stimulates megakaryocyte maturation. We found that Tpo is constitutively and ubiquitously expressed in all tissues examined, including bone marrow stromal cells, even in thrombocytopenia, thrombosis and steady-state condition in mice. Thus, platelet level in circulation is not regulated by Tpo gene expression. Furthermore, when the purified megakaryocytes were cocultured with the stromal cells, most of the megakaryocytes adhered to the stromal cells and remained unchanged, while free megakaryocytes induced proplatelet formation. Thus the stromal cells in bone marrow secrete Tpo and stimulate megakaryocytopoiesis, but the interaction of megakaryocytes with the stromal cells may suppress platelet formation. Study on signal transduction through Mp1 revealed that Tpo induces activation of JAK2 and Tyk2, which in turn activate STAT1, STAT3 and STAT5. Further, Tpo stimulates transcription factors GATA-1 and NF-E2, which induce differentiation markers, GPIIb/IIIa and Pm-1. In addition, Shc, Vav, Ras, Raf-1, MAPKK, MAPK and Pim-1 are also activated. Thus, Tpo activates a lineage-specific cascade as well as a specific JAK-STAT cascade and a common signaling cascade.
Leukemia 1997 Apr
PMID:Regulation of megakaryocytopoiesis by thrombopoietin and stromal cells. 920 16

Interferon alpha (IFN-alpha) induces cytogenetic responses of variable degree in patients with CML. We sought to establish the relationship between BCR-ABL transcript numbers measured by competitive two-step reverse transcription polymerase chain reaction (RT-PCR) and cytogenetic status in CML patients treated with IFN-alpha. All 398 samples from 163 patients investigated by RT-PCR were positive for BCR-ABL transcripts. In order to standardize results for variability in RNA and cDNA quality, we quantified total ABL transcripts in each sample as internal control. The BCR-ABL/ABL ratios correlated with the cytogenetic results. Quantitative nested PCR allowed the detection of residual BCR-ABL transcripts in all complete cytogenetic responders on IFN-alpha. We conclude that competitive PCR with internal controls is a reliable method for monitoring patients on IFN-alpha and reduces the need for repeated marrow investigations.
Leukemia 1997 Apr
PMID:Monitoring the efficiency of interferon-alpha therapy in chronic myelogenous leukemia (CML) patients by competitive polymerase chain reaction. 920 51

Antisense oligodeoxyribonucleotides (ODN) have been shown to produce a sequence-specific cleavage of BCR-ABL mRNA. They may therefore have clinical potential for purging harvests from chronic myeloid leukaemia (CML) patients, prior to autografting. Whilst ODN are highly effective in cell-free systems, their uptake into intact cells is very poor. We have previously reported that reversible permeabilisation of CML cell lines with Streptolysin-O (SL-O) can dramatically increase intracytoplasmic and nuclear ODN uptake. In this study, we examined whether SL-O permeabilisation could be used to enhance ODN uptake into bone marrow (BM) and peripheral blood stem cell (PBSC) harvests from CML patients, without undue toxicity. All 19 harvests studied were from patients in stable chronic phase of CML. Samples studied were either fresh BM harvests following leucoconcentration, fresh PBSC collections, or from previously cryopreserved harvests. Cells were permeabilised by SL-O to load them with fluorescein-labelled ODN. The proportion of permeabilised and viable cells was assessed by fluorescein uptake and propidium iodide exclusion, respectively, by flow cytometry. The effect of SL-O on ODN uptake and cell toxicity was unpredictable on simple mononuclear fractions of harvests. In contrast, SL-O consistently significantly enhanced ODN uptake in samples which were first selected for CD34-positive cells, and this was achieved without either direct toxicity or inhibition of CFU-GM growth. The SL-O concentration required for optimal permeabilisation varied considerably from case to case, in line with previous data on cell lines. PBSC harvests positively selected for CD34-positive cells tended to achieve superior permeabilisation to CD34 positively selected BM harvests. SL-O can be used to safely enhance the intracellular uptake of antisense ODN. This is best achieved on harvests which are first selected for CD34-positive cells.
Leukemia 1997 Sep
PMID:Preclinical studies of streptolysin-O in enhancing antisense oligonucleotide uptake in harvests from chronic myeloid leukaemia patients. 930 94

Philadelphia chromosome-positive (Ph+) hemopoietic cells predominate in patients with chronic myeloid leukemia (CML) in chronic phase, but some Ph presumably normal stem cells persist in most patients. Ph cells are relatively frequent, compared to mature cell populations, in primitive hemopoietic cell populations from CML patients. We have purified CD34+ cells from chronic phase CML blood and separated them into two fractions on the basis of adherence or non-adherence to tissue culture plastic. We also separated CD34+ CML cell populations into HLA-DR(hi) and HLA-DR(lo) fractions and CD38(hi) and CD38(lo) fractions by flow cytometry. The CD34+ cells that adhered to plastic were predominantly CD33-, CD38- and HLA(-)-DR; cells with these phenotypic properties were significantly rarer in the CD34+ non-adherent cell population (P = 0.008-0.02). Expression of p210 BCR/ABL mRNA by adherent, non-adherent, HLA-DR(hi) and HLA-DR(lo)CD34+ cell subpopulations was demonstrated by RT-PCR. Using fluorescence in situ hybridization (FISH) in conjunction with BCR and ABL probes we detected Ph+ and Ph- cells in both adherent and non-adherent CD34+ cell fractions of 15/15 patients studied and in the HLA-DR(lo) or CD38(lo) sorted CD34+ cell fractions. The concentration of Ph- cells in the adherent CD34+ cell fraction was three-fold higher than in the non-adherent fraction (P = 0.001). Ph- adherent cells were detected in untreated CML patients and as late as 6 years after diagnosis of CML in patients treated with hydroxyurea (HU) or interferon-alpha (IFN-alpha). We conclude that whilst appreciable numbers of Ph- primitive hemopoietic progenitors are present in the circulation in untreated patients and also in treated patients in late chronic phase, the majority of cells expressing CD34 but not CD33, CD38 or HLA-DR antigens, are part of the CML clone.
Leukemia 1997 Sep
PMID:BCR/ABL-negative progenitors are enriched in the adherent fraction of CD34+ cells circulating in the blood of chronic phase chronic myeloid leukemia patients. 930 2

Philadelphia chromosome (Ph)-positive acute lymphocytic leukemia (ALL) constitutes 15-35% of all ALL in adults. Its detection is prognostically significant. The Ph abnormality is usually detected through standard cytogenetic analysis but 20-30% of patients have insufficient metaphases (IM) with such analysis. To detect the BCR-ABL oncoprotein in peripheral blood specimen of patients with ALL at the time of diagnosis and at follow-up, a new sensitive technique of enhanced chemiluminescence Western blot (ECL-WB) analysis was investigated. Among 41 patients with newly diagnosed ALL, nine were Ph positive by cytogenetic studies; they were also BCR-ABL positive according to ECL-WB. Eight had p190 disease, and one had p210 disease. Among the 16 patients with IM, none demonstrated the oncoprotein through ECL-WB or through simultaneous Southern blot (SB) for p210 rearrangement. Follow-up studies were available for seven patients: four had detectable protein and three of them relapsed 4-20 weeks later; three had undetectable protein and one of them (who had low level protein at the time of diagnosis) relapsed 11 weeks later. Although none of the patients with IM at diagnosis had detectable protein according to ECL-WB, this was probably due to the small number of patients studied. One patient with IM studied at follow-up demonstrated the protein by ECL-WB. In summary, we describe a technique that is useful in the detection of p190/p210 ALL at diagnosis. It is less time consuming, and more cost effective than standard chromosome banding techniques. It may also detect the oncoprotein in cases with IM. Although a larger number of patients should be studied to prove its clinical usefulness, this technique may also be of value for monitoring residual disease at follow-up.
Leukemia 1997 Sep
PMID:Analysis of the BCR-ABL protein in Philadelphia chromosome-positive adult acute lymphocytic leukemia. 930 17

We have established an erythropoietin-dependent human leukemia cell line, AS-E2, from a patient with acute myeloid leukemia. These cells have many characteristics of late erythroid progenitor cells, they are positive for CD36, Glycophorin A, and CD71 but negative for CD41, and positive for benzidine and PAS staining. These cells express GATA-1 and have low affinity erythropoietin (EPO) receptor on their surface. Interestingly, AS-E2 cells are strictly dependent on EPO for their growth and survival; other cytokines including GM-CSF, stem cell factor, or IL-3 cannot support the growth of this cell line. These features are similar to late erythroid lineage cells, like normal BFU-E or CFU-E, and we have demonstrated that EPO stimulation induces the tyrosine phosphorylation of several proteins in AS-E2 cells including the EPO receptor and JAK2 kinase. This new cell line is a useful reagent to study biological and molecular events during the late stages of erythropoiesis, and to understand transforming events in human erythroid cells.
Leukemia 1997 Nov
PMID:Establishment and characterization of a new erythropoietin-dependent acute myeloid leukemia cell line, AS-E2. 936 30

We present the case of a two-year-old child with an atypical presentation of chronic myeloid leukemia. At diagnosis, he showed clinical and biological features of juvenile chronic myeloid leukemia (CML). However, eosinophilia was observed in blood and bone marrow. The bone marrow karyotype did not demonstrate the Philadelphia chromosome but BCR-ABL rearrangement was shown to be present by reverse transcriptase polymerase chain reaction (RT-PCR) analysis and confirmed by fluorescent in situ hybridization (FISH) analysis. Discussion centres on the differentiation between juvenile CML and childhood chronic myelogenous Leukemia and the importance of carrying out RT PCR for all juvenile CML cases.
 ...
PMID:Philadelphia negative BCR-ABL positive chronic myeloid leukemia mimicking juvenile chronic myeloid leukemia in a 2-year-old child. 938 69


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