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)

Therapy with interferon-alpha results in complete cytogenetic remission in 15-20% of patients with chronic myelogenous leukemia. Even during prolonged clinical follow-up, most of these patients do not relapse. However, because of the limited sensitivity of cytogenetic techniques (approximately 5%) and Southern blots (approximately 1%), it is uncertain whether the residual malignant clone becomes extinct or persists below the limit of detection in these patients. We used polymerase chain reaction to amplify the chimeric BCR-ABL transcripts in 18 patients with chronic myelogenous leukemia who became Ph1 chromosome negative while receiving treatment with interferon-alpha, either alone or in combination with interferon-gamma. At the time of study, these patients had been Ph1-negative for a median of 22+ months. Fifteen patients were positive for residual BCR-ABL transcripts. No residual BCR-ABL message was detected on analysis of multiple serial samples in three patients. In order to confirm these results, the samples from these three patients, along with positive and negative controls, were analyzed by two independent laboratories in a blinded fashion. In the first laboratory, RNA specimens from all three patients were considered negative using chemiluminescent acidinium-ester-labeled probes. In the second laboratory, samples from all three patients were also negative by conventional polymerase chain reaction (PCR). However, when a second round of amplification was carried out on the amplified samples using a different combination of primers, samples from two of the three patients were positive. The results confirm the presence of a small proportion of BCR-ABL-positive cells in the majority of patients who are in complete remission and highlight some of the potential problems of PCR-based analysis. There is a need to standardize PCR methodology and potential confounding factors need to be addressed before PCR can be generally applied to analysis of minimal residual disease in CML. The implications of BCR-ABL positivity for these patients are discussed.
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PMID:Minimal residual disease in interferon-treated chronic myelogenous leukemia: results and pitfalls of analysis based on polymerase chain reaction. 164 Jul 25

A substantial minority of patients with chronic myeloid leukaemia (CML) achieve a complete response to treatment with interferon-alpha (IFN-alpha), defined as the disappearance of Philadelphia chromosome positive metaphases or, for patients who are Philadelphia chromosome negative but BCR-ABL positive, the disappearance of the leukaemic clone as assayed by Southern blot. We have measured the levels of BCR-ABL transcripts in 20 such patients by quantitative PCR. Results were standardized for both quality and quantity of cDNA by quantification of ABL as an internal control. All 20 patients had evidence of residual disease; the median number of transcripts was 750/micrograms RNA (range 10-22,000) and the median BCR-ABL/ABL ratio was 0.17% (range 0.0008-3.6%). Our findings show that CML has not been eradicated in any patient and that the quantity of residual disease in complete responders may vary by as much as four orders of magnitude.
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PMID:Variable numbers of BCR-ABL transcripts persist in CML patients who achieve complete cytogenetic remission with interferon-alpha. 860 27

In chronic myeloid leukemia (CML) the proto-oncogene c-abl from chromosome 9 q34 is translocated to the breakpoint cluster region (bcr) gene on chromosome 22 q11. This translocation results in a BCR-ABL fusion gene, which encodes chimeric fusion oncoproteins p210BCR-ABL. Here we demonstrate that a peptide with joining region sequence ATGFKQSSKALQRPVAS (eight amino acids (aa) encoded by BCR exon 3; one novel lysine, encoded by the fusion codon; eight aa encoded by ABL exon 2) is immunogenic to human T cells. Primary immune response induction with this peptide resulted in a HLA DR2(DRB1*1501) restricted CD4+ BCR-ABL peptide specific T cell line P1. Responses of P1 were negatively affected by individual aa replacement by alanine at eight aa positions within the 17mer peptide (F4, K5, Q6, K9, L11, Q12, R13, P14). These findings were supported by experiments with a panel of overlapping 11mer b3a2 peptides. Only two of these peptides with an aa sequence encompassing all residues which could not be replaced by alanine induced P1 proliferation. Since presentation of cytosolic oncoproteins as peptides by DR molecules has been observed, the present findings provide a possible explanation for post interferon-alpha persisting remissions in spite of the presence of BCR-ABL PCR positive progenitors.
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PMID:Recognition of peptides corresponding to the joining region of p210BCR-ABL protein by human T cells. 764 23

The recently cloned ligand binding component of the type I human interferon-alpha/beta receptor (IFN-alpha/beta R) and its soluble analogue (p40) were characterized. p40 is a potent inhibitor of type I IFNs and antibodies directed against p40 completely block the activity of type I IFNs in human cells. These antibodies immunoprecipitate cellular 102-kDa (major) and 51-kDa (minor) forms of IFN-alpha/beta R. We find that the 51-kDa IFN-alpha/beta R. Two types of cDNA clones were isolated and sequenced, a 1.5-kb cDNA coding for the transmembrane 51-kDa IFN-alpha/beta R and a 4.5-kb cDNA coding for p40. In addition to ligand binding, IFN-alpha/beta R is directly involved in signaling, because it becomes phosphorylated at Tyr residues on ligand binding and it is physically associated with the cytoplasmic tyrosine kinase JAK1.
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PMID:Soluble and membrane-anchored forms of the human IFN-alpha/beta receptor. 775 50

The clinical status of a homogeneous cohort of long-term survivors of allogeneic marrow transplantation was assessed and residual leukaemia was studied by reverse transcription polymerase chain reaction for leukaemia specific BCR-ABL mRNA. The group comprised 34 consecutive patients with CML in chronic phase treated by chemoradiotherapy and transplantation of bone marrow from HLA-identical sibling donors between February 1981 and December 1983 in the joint Hammersmith-Northwick Park programme. The probability of survival at 10 years was 59 +/- 17%. Eighteen of the 19 surviving (95%) patients have Karnofsky scores of 90 or 100% indicative of a good performance status. One of the survivors had evidence of relapse 6.5 years after transplant but has since been restored to complete remission by treatment with interferon-alpha followed by donor leucocyte transfusions. Surprisingly, 2 of the 19 patients who have been in remission for over 10 years have molecular evidence of persisting leukaemic cells. Quantification by competitive PCR indicated that the malignant clone persisted at low levels. The data suggest that the majority of long-term survivors after BMT for CML are in good health and may be regarded as cured. Some long-term survivors, however, may still harbour residual leukaemic cells and continued monitoring for late relapse is warranted. Late relapse is amenable to further therapy with leukocyte transfusions from the original marrow donor.
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PMID:Detection of residual leukaemia more than 10 years after allogeneic bone marrow transplantation for chronic myelogenous leukaemia. 785 36

Interferon-alpha induces durable cytogenetic remissions in about one-quarter of newly diagnosed patients with chronic myelogenous leukemia (CML). Even so, after short-term follow-up, previous studies have shown that residual leukemic cells can be detected by the polymerase chain reaction (PCR) in all of these individuals. The objectives of our study were therefore to obtain long-term follow-up data on residual disease in a cohort of complete responders and to determine if leukemic cells with clonogenic potential are present in patients despite the absence of relapse. We performed (a) serial analysis of blood and/or bone marrow for a reverse transcriptase PCR amplified BCR-ABL transcript at times well beyond the point that cytogenetic remission was first attained and (b) reverse transcriptase PCR of individually plucked myeloid and erythroid colonies for the presence of the same transcript. Seven CML patients who had previously attained complete cytogenetic remission while on interferon-alpha were investigated. Six of the seven patients were in complete cytogenetic remission at the time of analysis, whereas one patient had early evidence of cytogenetic relapse. With ongoing therapy, five patients with the longest follow-up eventually achieved PCR negativity at time periods of 27, 32, 36, 49, and 67 mo after a complete cytogenetic remission was first noted. Even so, residual disease was detected in progenitor cells derived from two patients, each of whom had been in continuous cytogenetic remission for approximately 2.5 and 3.5 yr, respectively. Progenitors expressing BCR-ABL transcripts were also detected in the patient with early cytogenetic relapse. These observations demonstrate that residual disease resides in colony-forming cells that should have the potential to repopulate the bone marrow. However, the presence of a minority of Ph-positive CML progenitor cells for a very long period of time is still compatible with durable remission, confirming that a situation of tumor dormancy may be induced in CML by interferon therapy.
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PMID:Persistence of dormant leukemic progenitors during interferon-induced remission in chronic myelogenous leukemia. Analysis by polymerase chain reaction of individual colonies. 792 13

We have produced a cell line which lacks the protein tyrosine kinase JAK1 and is completely defective in interferon response. Complementation of this mutant with JAK1 restored the response, establishing the requirement for JAK1 in both the interferon-alpha/beta and -gamma signal transduction pathways. The reciprocal interdependence between JAK1 and Tyk2 activities in the interferon-alpha pathway, and between JAK1 and JAK2 in the interferon-gamma pathway, may reflect a requirement for these kinases in the correct assembly of interferon receptor complexes.
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PMID:The protein tyrosine kinase JAK1 complements defects in interferon-alpha/beta and -gamma signal transduction. 823 50

One hundred and forty-three patients with p210 BCR-ABL-positive leukemia were studied for coexpression of p190 BCR-ABL mRNA. p190 mRNA was detected in 14 of 16 (88%) patients with chronic-phase chronic myeloid leukemia (CML) at diagnosis, in 10 of 10 (100%) CML patients in blast crisis, in 75 of 107 (70%) CML patients receiving interferon-alpha (IFN-alpha), and 10 of 10 (100%) patients with p210 BCR-ABL-positive acute lymphoblastic leukemia (ALL). Neither p210 nor p190 BCR-ABL transcripts were detected in normal healthy adults (n = 20). The numbers of p190 transcripts determined by competitive PCR in patients with CML were low compared with the numbers of p210 transcripts. The median numbers of p210 and p190 transcripts per unit volume of cDNA in positive samples were 1.0 x 10(5) (range, 15 to 1.4 x 10(6)) and 10 (range, 10 to 2.9 x 10(3)), respectively. The numbers of p190 and p210 transcripts were significantly correlated in individual samples (r = .65, P < .001). The median number of p210 BCR-ABL transcripts was significantly lower in samples negative for p190 BCR-ABL transcripts than in samples in which p190 BCR-ABL transcripts were identified (3.1 x 10(3)[n = 73] v 1.0 x 10(5)[n = 115]; P < .0001). The median ratio of p190 to p210 BCR-ABL mRNA was not significantly different between chronic phase CML (1.9 x 10(-4)) and CML in blast crisis (1.7 x 10(-4)). The median ratio in p210 ALL was also low (1.9 x 10(-3)) but significantly higher than that of CML. We conclude that pl90 BCR-ABL transcripts are frequently present at a low level in p210 BCR-ABL-positive leukemias. p190 mRNA may arise through alternative or missplicing and its presence is probably of no pathogenetic significance.
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PMID:p190 BCR-ABL mRNA is expressed at low levels in p210-positive chronic myeloid and acute lymphoblastic leukemias. 865 35

The LH2 gene encodes a putative transcription factor containing two N-terminal LIM and one C-terminal HOX domains. The LH2 locus was mapped to 9q33-34.1, centromeric to the ABL gene. In a recent report, it was suggested that high levels of LH2 expression are consistently observed in chronic myeloid leukemia (CML) patients, whereas no transcription is detected in normal individuals. This led to the hypothesis that aberrant expression of LH2 may represent an additional mechanism for malignant cell proliferation in CML. We have studied the expression of LH2 in leucocytes from patients with CML or with other chronic myeloproliferative disorders (CMD), and from normal individuals, using an optimised reverse-transcription and polymerase chain reaction (PCR) technique. Twenty-seven out of 29 cDNA samples from normal individuals (93%), 49 out of 51 samples from CML patients (96%) and 20 out of 20 from Philadelphia chromosome-negative CMD showed evidence of LH2 expression. Similarly, LH2 transcription was also detected in leucocytes from CML patients in complete cytogenetic remission after treatment with interferon-alpha. Furthermore, all 36 EBV-induced lymphoblastoid cell lines established from six chronic phase CML patients showed unequivocal LH2 expression, regardless of the BCR-ABL status of the line (9 BCR-ABL positive, 27 BCR-ABL negative). We conclude that LH2 expression is not confined to CML cells, and that the t(9;22)(q34;qll) does not promote 'de novo' transcriptional activation of this gene.
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PMID:Expression of the LH2 gene in chronic myeloid leukaemia cells. 868 90

Tyk2 and JAK1, members of the Janus kinase (JAK) family of protein tyrosine kinases, are required for interferon-alpha/beta binding and signaling. Both enzymes are associated with the interferon-alpha/beta receptor, and upon ligand binding, they undergo tyrosine phosphorylation and catalytic activation in an interdependent manner. To identify residues involved in Tyk2 regulation and to understand the basis of the interdependence of Tyk2 and JAK1, six mutated versions of Tyk2 bearing single or multiple point mutations in the tyrosine kinase domain were studied in a cell line lacking endogenous Tyk2. The Y1054F/Y1055F substitutions in the putative activation loop prevented ligand-dependent activation of Tyk2, without abolishing its catalytic potential. The K930R mutation in the ATP binding site generated a kinase-negative protein, which however, still became phosphorylated upon interferon-alpha treatment. The Y1054F/Y1055F substitutions in this kinase-negative Tyk2 abolished the induced phosphorylation. These results indicate that Tyk2 is activated by phosphorylation on Tyr-1054 and/or Tyr-1055 and that this phosphorylation requires another kinase, most likely JAK1. While the Tyk2 forms mutated on Tyr-1054 and Tyr-1055 or on Lys-930 allowed some inducible gene expression, the combination of the three point mutations totally abolished signaling.
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PMID:Interferon-alpha-dependent activation of Tyk2 requires phosphorylation of positive regulatory tyrosines by another kinase. 870 90


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