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

WT1 (Wilms tumor gene) expression is a new tumor marker of leukemic blast cells of AML, ALL, and CML. Minimal residual disease (MRD) of leukemia can be detected at frequencies as low as 1 in 10(3) to 10(4) normal bone marrow (BM) cells and 1 in 10(5) normal peripheral blood (PB) cells by means of the quantitation of expression levels of the WT1 gene using reverse transcriptase-polymerase chain reaction (RT-PCR). This is regardless of the types of leukemia or the presence or absence of tumor-specific DNA markers. Thus, the WT1 assay makes it possible to rapidly assess the effectiveness of treatment and to evaluate the degree of eradication of leukemic cells in individual leukemia patients. Moreover, molecular relapse using PCR can be diagnosed by the monitoring of WT1 expression levels in BM or PB 1-24 months (means, 7 months for BM and 8 months for PB) before the clinical relapse became apparent. In case of rapid or gradual increase in WT1 expression levels to or over 10(-2) after return to normal BM levels during CR; or retention of the WTI expression at levels near or over 10(-2) in BM without return to normal BM levels even in CR (WT1 expression level in K562 cells was defined as 1.0), it seems that clinical relapse is impending. Since WT1 antisense oligomers inhibit the growth of leukemic cells, it is apparent that the WT1 gene plays an important role in leukemogenesis.
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PMID:Wilms tumor gene (WT1) as a new marker for the detection of minimal residual disease in leukemia. 966 76

The Wilms tumor (WT1) gene has been reported to be preferentially expressed in acute leukemia cells, regardless of leukemia subtype and chronic myelogenous leukemia cells in blast crisis, but not in normal cells. This finding suggests strongly that WT1 protein is a potential target of immunotherapy for human leukemia. In this study, we established a CD8(+) cytotoxic T-lymphocyte (CTL) clone directed against a WT1-derived peptide and examined its immunologic actions on leukemia cells. A CD8(+) CTL clone, designated TAK-1, which lysed autologous cells loaded with a WT1-derived 9-mer peptide consisting of the HLA-A24 (HLA-A*2402)-binding motifs was established by stimulating CD8(+) T lymphocytes from a healthy individual repeatedly with WT1 peptide-pulsed autologous dendritic cells. TAK-1 was cytotoxic to HLA-A24-positive leukemia cells expressing WT1, but not to HLA-A24-positive lymphoma cells that did not express WT1, HLA-A24-negative leukemia cells, or HLA-A24-positive normal cells. Treating leukemia cells with an antisense oligonucleotide complementary to the WT1 gene resulted in reduced TAK-1-mediated cytotoxicity, suggesting that target antigen of TAK-1 on leukemia cells is the naturally processed WT1 peptide in the context of HLA-A24. TAK-1 did not inhibit colony formation by normal bone marrow cells of HLA-A24-positive individuals. Because WT1 is overexpressed ubiquitously in various types of leukemia cells, but not in normal cells, immunotherapy using WT1 peptide-specific CTL clones should be an efficacious treatment for human leukemia. (Blood. 2000;95:286-293)
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PMID:HLA class I-restricted lysis of leukemia cells by a CD8(+) cytotoxic T-lymphocyte clone specific for WT1 peptide. 1060 14

The Wilms' tumor gene WT1 is expressed at high levels not only in acute myelocytic and lymphocytic leukemia and in chronic myelocytic leukemia but also in various types of solid tumors including lung cancers. To determine whether the WT1 protein can serve as a target Ag for tumor-specific immunity, three 9-mer WT1 peptides (Db126, Db221, and Db235), which contain H-2Db-binding anchor motifs and have a comparatively higher binding affinity for H-2Db molecules, were tested in mice (C57BL/6, H-2Db) for in vivo induction of CTLs directed against these WT1 peptides. Only one peptide, Db126, with the highest binding affinity for H-2Db molecules induced vigorous CTL responses. The CTLs specifically lysed not only Db126-pulsed target cells dependently upon Db126 concentrations but also WT1-expressing tumor cells in an H-2Db-restricted manner. The sensitizing activity to the Db126-specific CTLs was recovered from the cell extract of WT1-expressing tumor cells targeted by the CTLs in the same retention time as that needed for the synthetic Db126 peptide in RP-HPLC, indicating that the Db126-specific CTLs recognize the Db126 peptide to kill WT1-expressing target cells. Furthermore, mice immunized with the Db126 peptide rejected challenges by WT1-expressing tumor cells and survived for a long time with no signs of autoaggression by the CTLs. Thus, the WT1 protein was identified as a novel tumor Ag. Immunotherapy targeting the WT1 protein should find clinical application for various types of human cancers.
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PMID:Cancer immunotherapy targeting Wilms' tumor gene WT1 product. 1065 36

The product of the Wilms' tumor gene WT1 is a transcription factor overexpressed not only in leukemic blast cells of almost all patients with acute myeloid leukemia, acute lymphoid leukemia, and chronic myeloid leukemia, but also in various types of solid tumor cells. Thus, it is suggested that the WT1 gene plays an important role in both leukemogenesis and tumorigenesis. Here we tested the potential of WT1 to serve as a target for immunotherapy against leukemia and solid tumors. Four 9-mer WT1 peptides that contain HLA-A2.1-binding anchor motifs were synthesized. Two of them, Db126 and WH187, were determined to bind to HLA-A2.1 molecules in a binding assay using transporter associated with antigen processing-deficient T2 cells. Peripheral blood mononuclear cells from an HLA-A2.1-positive healthy donor were repeatedly sensitized in vitro with T2 cells pulsed with each of these two WT1 peptides, and CD8(+) cytotoxic T lymphocytes (CTLs) that specifically lyse WT1 peptide-pulsed T2 cells in an HLA-A2.1-restricted fashion were induced. The CTLs also exerted specific lysis against WT1-expressing, HLA-A2.1-positive leukemia cells, but not against WT1-expressing, HLA-A2.1-negative leukemia cells, or WT1-nonexpressing, HLA-A2. 1-positive B-lymphoblastoid cells. These data provide the first evidence of human CTL responses specific for the WT1 peptides, and provide a rationale for developing WT1 peptide-based adoptive T-cell therapy and vaccination against leukemia and solid tumors.
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PMID:Human cytotoxic T-lymphocyte responses specific for peptides of the wild-type Wilms' tumor gene (WT1 ) product. 1066 72

Continuous Wilms' tumor gene (WT1) expression is a typical feature of leukemic blasts in AML, ALL, and blast crisis CML patients. It is easily detectable by a variety of RT-PCR protocols, which differ mainly in their sensitivity. The nuclear WT1 protein can be found in blasts of approximately 50-60% of acute leukemia patients at diagnosis. Conversely, WT1 is only transiently expressed in normal hemopoiesis. Early CD34+ hemopoietic progenitors express WT1, whereas no WT1 mRNA transcripts can be found in mature blood cells and differentiation-induced committed CD34- progenitors. As a powerful complementary diagnostic tool, testing for WT1 expression can be helpful to discriminate between eosinophilic leukemia (EoL) patients and patients with idiopathic hypereosinophilic syndromes. Conflicting data about the usefulness of testing for WT1 expression to monitor minimal residual disease (MRD) in treated leukemia patients will be discussed. Finally, research strategies to circumvent shortcomings in detecting leukemia-associated WT1 expression will be outlined.
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PMID:Analysis of Wilms tumor gene (WT1) expression in acute leukemia patients with special reference to the differential diagnosis between eosinophilic leukemia and idiopathic hypereosinophilic syndromes. 1067

Hematologic malignancies such as acute and chronic myeloid leukemia are characterized by the malignant transformation of immature CD34(+) progenitor cells. Transformation is associated with elevated expression of the Wilm's tumor gene encoded transcription factor (WT1). Here we demonstrate that WT1 can serve as a target for cytotoxic T lymphocytes (CTL) with exquisite specificity for leukemic progenitor cells. HLA-A0201- restricted CTL specific for WT1 kill leukemia cell lines and inhibit colony formation by transformed CD34(+) progenitor cells isolated from patients with chronic myeloid leukemia (CML), whereas colony formation by normal CD34(+) progenitor cells is unaffected. Thus, the tissue-specific transcription factor WT1 is an ideal target for CTL-mediated purging of leukemic progenitor cells in vitro and for antigen-specific therapy of leukemia and other WT1-expressing malignancies in vivo.
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PMID:Selective elimination of leukemic CD34(+) progenitor cells by cytotoxic T lymphocytes specific for WT1. 1073 85

Wilms' tumor gene WT1 mRNA is a new marker of leukemic blast cells for AML, ALL, and CML. Minimal residual disease(MRD) of leukemia can be detected at frequencies as low as 1 in 10(3) to 10(4) normal bone marrow cells and 1 in 10(5) normal peripheral blood mononuclear cells by means of the quantitation of WT1 mRNA(WT1 assay) using reverse transcriptase-polymerase chain reaction. Thus, the WT1 assay makes it possible to rapidly assess the effectiveness of treatment and to evaluate the degree of eradication of leukemic cell in individual leukemia patients. Furthermore, WT1 assay can continuously assess the disease progression of myelodysplastic syndromes(MDS) and predict the evolution of MDS to overt AML within 6 months.
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PMID:[Genetic diagnosis of leukemia: diagnosis of relapse and complete remission, and prediction of leukemia onset]. 1080 19

Interleukin-12 (IL-12) has potent antitumor activities. We examined whether IL-12 enhanced the cytotoxicity of peripheral blood mononuclear cells (PBMNC) and decreased leukemia cells in 30 patients with leukemia or myelodysplastic syndromes (MDS): 12 acute myeloid leukemia (AML) (five in complete remission (CR) and seven in non-CR); six chronic myeloid leukemia (CML); and 12 MDS (three refractory anemia (RA), eight RA with excess of blasts and one chronic myelomonocytic leukemia). PBMNC from patients and five healthy volunteers were cultured at 5 x 10(5)/ml parallel with or without 100 units/ml of IL-12 for 3 days. Cytotoxicity of PBMNC against K562 cells was assessed by flow cytometry. To quantify the amount of leukemia cells, WT1 mRNA was measured by competitive reverse transcription polymerase chain reaction (RT-PCR), since WT1 mRNA is considered as a marker of minimal residual disease (MRD) in leukemia or MDS. The cytotoxicity of non-IL-12-treated PBMNC of 30 patients was 13.4+/-9.3% at the effector to target (E:T) ratio of 20:1, and significantly lower than that of normal subjects (25.7+/-8.4%). The cytotoxicity increased to 30.6+/-17.9% in the IL-12-treated PBMNC. WT1 mRNA in PBMNC of five healthy volunteers was less than 10(3) copies/microg of total RNA. Following the 3-day IL-12 treatment, mean WT1 mRNA of PBMNC was reduced from 10(4.8) to 10(4.2) copies/microg of total RNA in six CML patients, from 10(5.4) to 10(4.8) copies/microg in 12 MDS patients and from 10(5.0) to 10(4.2) copies/microg in five AML patients in CR, but not reduced in five of seven AML in non-CR. These results showed that IL-12 significantly enhanced PBMNC cytotoxicity and decreased the quantity of leukemia cells in PBMNC of most patients with MDS, CML and AML in CR. IL-12 might be of considerable benefit in the elimination of MRD in patients with hematological malignancies.
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PMID:In vitro IL-12 treatment of peripheral blood mononuclear cells from patients with leukemia or myelodysplastic syndromes: increase in cytotoxicity and reduction in WT1 gene expression. 1099 11

WT1 is an oncogenic protein expressed by the Wilms' tumor gene and overexpressed in the majority of acute myelogenous leukemias (AMLs) and chronic myelogenous leukemias (CMLs). The current study analyzed the sera of patients with AML and CML for the presence of antibodies to full-length and truncated WT1 proteins. Sixteen of 63 patients (25%) with AML had serum antibodies reactive with WT1/full-length protein. Serum antibodies from all 16 were also reactive with WT1/NH2-terminal protein. By marked contrast, only 2 had reactivity to WT1/COOH-terminal protein. Thus, the level of immunological tolerance to the COOH terminus may be higher than to the NH2 terminus. The WT1/COOH-terminal protein contains four zinc finger domains with homology to other self-proteins. By implication, these homologies may be related to the increased immunological tolerance. Results in patients with CML were similar with antibodies reactive to WT1/full-length protein detectable in serum of 15 of 81 patients (19%). Antibodies reactive with WT1/NH2-terminal protein were present in the serum of all 15, whereas antibodies reactive with WT1/COOH-terminal protein were present in only 3. By contrast to results in leukemia patients, antibodies reactive with WT1/full-length protein were detected in only 2 of 96 normal individuals. The greater incidence of antibody in leukemia patients provides strong evidence that immunization to the WT1 protein occurred as a result of patients bearing malignancy that expresses WT1. These data provide further stimulus to test therapeutic vaccines directed against WT1 with increased expectation that the vaccines will be able to elicit and/or boost an immune response to WT1.
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PMID:WT1-specific serum antibodies in patients with leukemia. 1130 Apr 70

The Wilms' tumour gene (WT1) has been suggested as a powerful parameter for molecular monitoring of minimal residual disease (MRD) in leukaemias. However, molecular monitoring via WT1 RNA levels is far from being routinely performed, which is possibly owing to the complex and inaccurate quantitative reverse transcription polymerase chain reaction (RT-PCR) procedures. Using a newly-developed quantitative real time RT-PCR, we measured WT1 transcripts in peripheral blood leucocytes of patients with acute myeloid (AML), acute lymphoid (ALL) and chronic myeloid leukaemia (CML). While healthy blood donors did not show measurable amounts of WT1 transcripts, WT1 RNA levels were detectable in all types of leukaemia. Furthermore, intraindividual WT1 transcript kinetics were exclusively dependent on disease progression, treatment and subsequent disease outcome. Using this approach, we could distinguish between treatment response and failure within the first days of therapeutic intervention. Moreover, gradually rising WT1 levels over a period of weeks and months paralleled long-term disease progression and appeared to be a prognostic indicator for subsequent clinical relapse. A linear correlation between quantities of WT1 and bcr/abl fusion transcripts could be seen in CML. We conclude that quantitative assessment of WT1 transcripts using real-time PCR is an appropriate method for molecular monitoring of AML, ALL and CML, and can be used independently for both short- and long-term monitoring of leukaemia patients.
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PMID:Fluorescent 5'-exonuclease assay for the absolute quantification of Wilms' tumour gene (WT1) mRNA: implications for monitoring human leukaemias. 1152 49


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