Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023473 (chronic myeloid leukemia)
 18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The v-abl protein of Abelson murine leukemia virus is a tyrosine-specific kinase. Its normal cellular homolog, murine c-abl, does not possess detectable tyrosine kinase activity in vitro. Previously, we have detected tyrosine kinase activity in vitro for an altered c-abl gene product (c-abl P210) in the K562 human chronic myelogenous leukemia cell line. The expression of this variant c-abl gene product correlates with chromosomal translocation and amplification of the c-abl gene in K562 cells. Like v-abl, c-abl P210 is a fusion protein containing non-abl sequences near the amino terminus of c-abl. We compared the in vitro tyrosine kinase activity of c-abl P210 with that of wild-type murine v-abl. The remarkable similarities of these two proteins with respect to cis-acting autophosphorylation, trans-acting phosphorylation of exogenous substrates, and kinase inhibition, using site-directed abl-specific antisera, suggested that c-abl P210 could function similarly to v-abl in vivo. In addition, c-abl P210 possessed an associated serine kinase activity in immunoprecipitates. The serine kinase activity was not inhibited by site-directed, abl-specific antisera that inhibit the tyrosine kinase activity, suggesting that the serine kinase activity is not an intrinsic property of c-abl P210. Thus, the activation of the c-abl gene in a human leukemia cell line may have functional consequences analogous to activation of the c-abl gene in Abelson murine leukemia virus.
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PMID:Activation of the c-abl oncogene by viral transduction or chromosomal translocation generates altered c-abl proteins with similar in vitro kinase properties. 403 28

The transforming gene of the Abelson murine leukaemia virus, v-abl, contains two open reading frames (orf). The 5' orf encodes a tyrosine-specific protein kinase while the 3' orf has the capacity to code for an 18,000 Mr protein. However, no 3' orf product has yet been identified. Using probes capable of distinguishing between the 5' and 3' orfs of v-abl, we have examined the abl-related transcripts present in human haematopoietic cells and leukaemia-derived cell lines, including the chronic myeloid leukaemia-derived cell line K562. Our results indicate that transcripts of 6 kb, 7 kb and 8 kb (kilobase, 10(3) base-pairs) show strong homology to v-abl 5' protein kinase-encoding orf sequences, but are devoid of any sequences from the v-abl 3' orf. In addition, transcripts of 5 kb, 3 kb, 1.6 kb and 1.4 kb, reacting with both 5' orf and 3' orf probes, were observed. The latter species, with coding sequences from both the tyrosine kinase and the putative 18,000 Mr protein, must be transcribed from the human c-abl gene as this is apparently the only human gene containing sequences homologous to the v-abl 3' orf. The 6 kb, 7 kb and 8 kb transcripts may arise either from the c-abl gene through differential splicing, or from one of the three other regions of the human genome with sequences homologous to the 5' orf of v-abl. Examination of genomic DNA from the K562 cell line revealed that the amplification of abl-related sequences, which is presumed to result in the elevated levels of the 8 kb transcript found in this cell line, does not involve sequences homologous to the v-abl 3' orf. This lends credence to the idea that the 8 kb transcript may derive from an abl-related gene other than c-abl. While the significance of the 3' orf of v-abl remains unknown, the data presented strongly suggest the existence of at least two distinct abl-related proteins in human haematopoietic cells.
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PMID:Two families of abl-related transcripts in human haematopoietic cells differing in their homology to v-abl. 608 79

Structural rearrangements of specific cellular sequences (c-onc genes) homologous to acute transforming retrovirus oncogenes (v-onc genes) have been recently described in various malignancies. Here we show that human cellular sequences (c-abl) homologous to the transforming sequences of the mouse Abelson leukemia virus (v-abl) are amplified some 4- to 8-fold in K-562, a Philadelphia chromosome-positive cell line derived from a patient with chronic myelogenous leukemia in blast crisis. Restriction analysis of K-562 and other human DNA samples reveals a significant rearrangements of the c-abl sequences in this cell line. In addition, investigation of v-abl-related cytoplasmic RNA reveals relatively high levels of these sequences in K-562 compared to other normal and leukemia cells. We have also observed that lambda light chain constant region immunoglobulin genes are amplified in K-562, whereas kappa light chain sequences exhibit no amplification. These results are discussed within the context of the possibility that these Philadelphia chromosome-positive cells exhibit a reciprocal translocation involving chromosome 9 (containing c-abl) and chromosome 22 (containing the lambda light chain genes).
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PMID:Rearrangement and amplification of c-abl sequences in the human chronic myelogenous leukemia cell line K-562. 630 52

K562 cell line, established from a patient in the blast crisis of chronic myeloid leukemia, expresses high levels of c-myc and bcr/abl gene products. Exposure of K562 cells to 5-fluorouracil (5-FU) resulted in a marked benzidine-positive erythroid differentiation with concomitant reduction in cell proliferation. No change in c-myc mRNA or protein levels occurred during 96 h of drug treatment. In contrast, a biphasic change of p210bcr/abl and the abl-associated kinase activities was observed upon treatment with 5-FU. The change in p210bcr/abl expression may be mediated at the translational level, since the steady-state level and the enzymatic activity of p210bcr/abl are reduced, whereas bcr/abl mRNA levels are unaltered. The results are consistent with the existence of pleiotropic differentiation pathways in K562 cells.
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PMID:Induction of erythroid differentiation by 5-fluorouracil in K562 leukemia cells. 749 14

Cytogenetic analysis is considered pivotal for assessing the remission rate in CML patients on IFN therapy. On the basis of general agreement, at least 25 metaphases should be analyzed in each case. The main limitations to this approach are: 1) the small number of analyzable metaphases generally found in cytogenetic preparations from IFN-alpha-treated patients; and 2) the inability of this technique for scoring interphase cells. We compared the results of cytogenetic analysis and double-color FISH detection of bcr/abl genes fusion in 13 CML patients on IFN-alpha therapy (marrow sampling for cytogenetic and FISH analysis was carried out after 12 months in all patients and repeated after 18 months of IFN therapy in patients 4, 6, and 8). In five specimens, 20 to 25 cells were evaluable for cytogenetic examination, in another five no analyzable metaphases were scored, and in the remaining six samples two to 14 cells could be analyzed. With FISH detection at least 100 cells were easily scored in each specimen (mean number, 175). Comparing the results carried out with the two methods in different samples it emerged that cytogenetic analysis led to improper conclusions as regards the rate of Ph positivity, even in those patients where 20-25 metaphases were analyzed. Although many more cases have to be studied to establish the role of FISH analysis in Ph-positive patients, we are of the opinion that cytogenetic analysis is unfit for easily and accurately assessing the actual quality of remission in IFN-treated subjects.
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PMID:Cytogenetic analysis is non-informative for assessing the remission rate in chronic myeloid leukemia (CML) patients on interferon-alpha (IFN-alpha) therapy. 749 36

CD34+DR- and CD34+DR+ cells were isolated from the marrow mononuclear cells of five patients with chronic myelogenous leukemia (CML) carrying the Philadelphia (Ph) chromosome. Analysis of bcr/abl hybrid mRNA in individual colonies from a single cell using reverse transcriptase polymerase chain reaction (RT-PCR) demonstrated the presence or absence of the hybrid mRNA. For patient 1 in the chronic phase of CML, the hybrid mRNA was detected in all colonies derived from CD34+DR+ and CD34+DR- hemopoietic progenitors. In contrast, for patient 2 in the chronic phase of CML, the mRNA was detected in all individual colonies from CD34+DR+ progenitors but not in any from CD34+DR- progenitors. For patient 3 in the chronic phase of CML, the mRNA was detected in all individual colonies from CD34+DR+ but in only some of the colonies from CD34+DR- progenitors. For patients 4 and 5 in the acute crisis of CML, the mRNA was found in a portion of colonies from CD34+DR+ and CD34+DR- progenitors. These results indicated that normal clones can persist in CD34+DR- progenitors in some patients with CML, even when chromosome analysis detects the Ph chromosome in all metaphases of bone marrow cells.
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PMID:Absence of bcr/abl gene in single hemopoietic progenitors in some patients with chronic myelogenous leukemia. 750 22

Long-term culture of marrow from patients with chronic myelogenous leukemia (CML) has been reported to favor the outgrowth of bcr/abl- progenitor cells in some patients. We examined the effect of the presence of soluble or transmembrane forms of stem cell factor (SCF) in long-term cultures of CML marrow. CD34-enriched cells from CML patients in advanced chronic phase or accelerated phase were plated on immortalized fetal liver stromal cells from homozygous SCF-deficient SI/SI mice (SI/SI4) with or without the addition of soluble human SCF, SI/SI4 cells expressing high levels of the transmembrane form of human SCF (SI/SIh220), or primary human allogeneic stroma. Cells were removed from cultures and plated weekly in colony assays. The clonagenic cell output from cultures completely lacking SCF was lower over the first 2 to 3 weeks, but by 5 weeks was similar to the clonagenic cell output from the other culture conditions. Analysis of bcr/abl transcripts from individual colonies showed a lower percentage of malignant progenitors present in long-term cultures completely deficient in SCF than under the other culture conditions, particularly compared with primary human stroma-containing long-term cultures. SCF may specifically favor malignant versus benign progenitor cells present in the marrow of CML patients, and an abnormal proliferative response to SCF in very primitive cells may be an underlying defect in the pathophysiology of this disease.
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PMID:Long-term culture of chronic myelogenous leukemia marrow cells on stem cell factor-deficient stroma favors benign progenitors. 753 38

The effect of donor/recipient histocompatibility on relapse in patients receiving T-cell-depleted (TCD) grafts for chronic myelogenous leukemia (CML) was evaluated. Specifically, we sought to determine whether TCD results in an attenuation of the graft-versus-leukemia (GVL) effect on recipients of unrelated marrow grafts similar to that observed in HLA-identical sibling marrow transplantations. This question was addressed by comparative analysis of the relapse rates in marrow grafts who otherwise received identical preparative regimens and graft-versus-host disease (GVHD) prophylaxis schedules (T-cell depletion with T10B9 monoclonal antibody and complement plus posttransplant cyclosporine) and by serial molecular analyses using the polymerase chain reaction (PCR) to detect the bcr/abl RNA transcript in patients transplanted with unrelated donor grafts. Patients transplanted with advanced disease (accelerated phase or blast crisis) had equally high relapse rates, regardless of whether they received HLA-identical sibling (56%;95% confidence interval [CI], 29% to 82%) or unrelated marrow grafts (8%; 95% CI, 0% to 28%) had a significantly lower incidence of relapse than did patients transplanted with HLA-identical marrow grafts (47%; 95% CI, 23% to 71%; P = .002). Because all patients were similarly treated, these data indicate that the lower relapse rate in these unrelated patients was caused by an augmented GVL effect that was most likely attributable to increased HLA disparity between donor and recipient. The probability of developing both acute and chronic GVHD was significantly increased in chronic-phase recipients of unrelated marrow grafts, suggesting that the enhanced GVL effect was at least partly GVHD-associated. The lack of such a finding in advanced disease patient receiving unrelated marrow grafts raises the possibility that clinically significant GVL effect after TCD marrow transplantation was limited and confined to patients with more indolent disease. Serial PCR analyses for the presence of the bcr/abl RNA transcript showed that the vast majority of patients transplanted in chronic phase with unrelated marrow grafts were persistently PCR-negative, indicating that the GVL effect was durable in these patients. Most of these patients were observed to become PCR negative within 1 to 2 months after transplantation, showing that early eradication of leukemia was possible with TCD marrow grafts. This study shows that the use of unrelated marrow grafts compensates for reduced GVL reactivity associated with TCD in patients transplanted for CML. Furthermore, these data indicate that, in selected patient populations with CML, TCD can be used to reduce GVHD without a commensurate compromise in the GVL effect.
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PMID:Use of unrelated marrow grafts compensates for reduced graft-versus-leukemia reactivity after T-cell-depleted allogeneic marrow transplantation for chronic myelogenous leukemia. 757 70

We investigated leukemic cells from a patient with chronic myelocytic leukemia (CML) and a normal 46,XX karyotype. Molecular studies revealed rearrangement of the M-bcr region and formation of BCR/ABL fusion mRNA with b3a2 configuration. Fluorescence in situ hybridization (FISH) using the abl probe showed signal on both chromosomes 9 band q34, while the bcr probe hybridized to one chromosome 22 and to one chromosome 9. In this case, as in three other cases recently described (Hagemeijer et al. and Nachava et al.), the bcr/abl rearrangement is shown to be on 9q34, instead of the usual location on 22q11.
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PMID:Reversed BCR/ABL rearrangement detected by FISH in Philadelphia negative chronic myelocytic leukemia. 762 6

The WT 1 gene has been isolated as a tumor suppressor gene of Wilms' tumor. Using reverse transcriptase-polymerase chain reaction (RT-PCR), relative levels of the WT 1 gene expression was examined in 87 patients with acute leukemia, 25 with chronic myelogenous leukemia (CML), and 24 with non-Hodgkin's lymphoma (NHL). Significant levels of the WT 1 gene were expressed in all leukemia patients, and for CML the levels increased as the clinical phase progressed. No point mutations were found in the WT 1 gene when samples from 15 acute leukemia patients were subjected to PCR single-strand conformation polymorphism analysis. In striking contrast to acute leukemia, the levels of WT1 gene expression for NHL were significantly low or even undetectable. The levels of WT 1 gene expression inversely correlated with the prognosis of acute leukemia. The quantification of the WT 1 gene expression made it possible to detect minimal residual disease (MRD) in acute leukemia regardless of the presence of absence of tumor-specific DNA markers. Simultaneous monitoring of MRD by RT-PCR using primers for specific DNA markers in four patients (two AML-M3 with PML/RAR-alpha, one AML-M2 with AML1/ETO, and one CML with bcr/abl) detected MRD comparable to that obtained from quantitation of WT 1 gene expression. In a patient with acute promyelocytic leukemia, the limits of leukemic cell detection by RT-PCR using either WT 1 or PML/RAR-alpha gene primers were 10(-3)-10(-4) and 10(-4) for bone marrow, and 10(-5) and 10(-4) for peripheral blood, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[WT 1 and leukemia]. 764 50


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