Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Through their ability to induce cytotoxic T-lymphocytes and inhibit Foxp3 T-regulatory cells, Escherichia coli expressing listeriolysin-O (LLO) and a model tumor antigen have been shown to exert strong antitumor activity. The aim of this study is to extend these observations to a self-protein and clinically relevant tumor antigen associated with most types of adult leukemia: Wilms tumor gene 1 (WT1). We demonstrate that an E. coli coexpressing LLO and WT1 is capable of inducing a strong antitumor effect against WT1-expressing tumors in vivo through its ability to induce cytotoxic T-lymphocytes and inhibit the function of Foxp3 T-regulatory cells. Furthermore, we have characterized the immunodominant epitope involved in this effect (NAPYLPSCL) and demonstrated that coinjection of NAPYLPSCL with E. coli-LLO resulted in an antitumor effect largely equivalent to that obtained with E. coli-LLO/WT1. Our data demonstrate that the results obtained with a clinically irrelevant model tumor antigen remain valid with a "real" tumor antigen and that the adjuvant properties of the E. coli-LLO vaccine can be exploited in conjunction with peptides. The results obtained in this study will facilitate the translation of this work to human studies by combining antigenic motifs relevant to specific human leukocyte antigen haplotypes with the adjuvant effect of E. coli-LLO.
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PMID:Development of an Escherichia coli expressing listeriolysin-O vaccine against Wilms tumor gene 1-expressing tumors. 1975 49

The Wilms' tumor gene 1 (WT1) encodes a transcription factor that is involved in normal cellular development and cell survival. WT1 mRNA is overexpressed in the minimal residual disease (MRD) of patients with hematopoietic malignancy patients, particularly acute myeloid leukemia (AML). MRD represents the condition with the low levels of leukemia cells in the bone marrow and is known as a sign of recurrence. In hematopoietic malignancies, definition of remission is based on the lack of MRD at submicroscopic level. Between December 2005 and June 2008, we started to measure WT1 mRNA levels in the peripheral blood (PB) from patients by quantitative real-time PCR in Aomori Prefectural Central Hospital. Three hundreds and eight samples from 95 patients were evaluated. The patients included AML (55 patients), acute lymphoblastic leukemia (11), myelodysplastic syndrome (20), malignant lymphoma (5), chronic myeloid leukemia (1), prostatic carcinoma (1), and leukopenia (2). Among the 55 AML patients, 21 patients were pretreated with remission induction therapy. In the clinical course of 21 patients, timely therapeutic approaches could be started for relapse by the early detection of WT1 mRNA overexpression before the morphological findings were apparent. Monitoring WT1 mRNA is helpful to identify patients at high-risk relapse. High overall survival rate (71.2%, 15/21, median: 24.6 months, range 1.1-35.6 months) was achieved in 3 years. The overall survival rate of 34 post-treatment patients was 61.7% (median: 23.5 months, range 0.13-126.5 months after treatment start). In conclusion, the WT1 mRNA level is a sensitive biomarker for monitoring MRD.
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PMID:WT1 mRNA level in peripheral blood is a sensitive biomarker for monitoring minimal residual disease in acute myeloid leukemia. 1977 35

Monitoring patients with multiple myeloma during and after treatment for the presence of residual myeloma cells (minimal residual disease - MRD) has been shown to give a major insight into the effectiveness of treatment. It has been reported that Wilms' tumor gene (WT1) expression levels measured by real-time quantitative polymerase chain reaction was useful as an indicator of minimal residual disease in leukemia and myelodysplastic syndrome. The aim of this study was to measure levels of WT1 expression, in order to find a possible association between the expression of this gene and multiple myeloma at diagnosis. If an association was found, the WT1 gene could be evaluated as an MRD marker by comparison with other prognostic factors. We investigated peripheral blood WT1 expression level measured by real-time light cycler quantitative polymerase chain reaction in 50 newly diagnosed multiple myeloma patients. The normal WT1 gene copy number was found to be <23/microl cDNA and all patients with myeloma were found to have normal WT1-mRNA levels. On this basis WT1 expression analyses is unlikely to be a useful genetic marker for routine clinical use in multiple myeloma patients at diagnosis.
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PMID:Expression of WT1 gene in multiple myeloma patients at diagnosis: is WT1 gene expression a useful marker in multiple myeloma? 2013 61

The Wilms' tumor 1 (WT1) gene is overexpressed in leukemia and various types of solid tumor, such as lung and colorectal cancer, and plays an oncogenic role in their tumorigenesis. Recent studies have demonstrated the potential of WT1-targeting cancer immunotherapy in clinical settings. As expression of WT1 protein in tumor cells is a prerequisite for WT1-targeting immunotherapy, immunohistochemical methods to detect WT1 protein with high sensitivity and specificity are required. In the present study, we developed a rabbit polyclonal antibody (WT1-R) against the 9-mer WT1 235 peptide, which is used for vaccination. The specificity of WT1-R was confirmed by immunoprecipitation, western blotting analysis, and competitive enzyme-linked immunosorbent assay. Immunocytochemistry showed the same reactivity against five cell lines (K562, Daudi, HT-180, SW480, and PC-14), whereas levels of WT1 mRNA expression determined by real-time qPCR (RT-PCR) analysis were not equivalent. Next, we examined the reactivity of WT1-R in tissue samples compared with a previously developed anti-WT1 antibody, 6F-H2. WT1-R showed greater sensitivity for detecting WT1 protein expression in samples from four different breast cancer patients than 6F-H2 antibody. The discrepancy in WT1 expression between these methods suggested that immunohistochemical detection of WT1 peptide may be advantageous for predicting the efficacy of WT1 vaccine compared to RT-PCR, and the highly sensitive WT1 antibody, WT1-R, may be useful to detect WT1 protein in tumors.
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PMID:Sensitive immunohistochemical detection of WT1 protein in tumors with anti-WT1 antibody against WT1 235 peptide. 2018 Aug 15

Wilms' tumor gene 1 (WT1) is a transcription factor involved in developmental processes. In adult hematopoiesis, only a small portion of early progenitor cells express WT1, whereas most leukemias show persistently high levels, suggesting an oncogenic role. We have previously characterized oncogenic BCR/ABL1 tyrosine kinase signaling pathways for increased WT1 expression. In this study, we show that overexpression of BCR/ABL1 in CD34+ progenitor cells leads to reduced expression of interferon regulatory factor 8 (IRF8), in addition to increased WT1 expression. Interestingly, IRF8 is known as a tumor suppressor in some leukemias and we investigated whether WT1 might repress IRF8 expression. When analyzed in four leukemia mRNA expression data sets, WT1 and IRF8 were anticorrelated. Upon overexpression in CD34+ progenitors, as well as in U937 cells, WT1 strongly downregulated IRF8 expression. All four major WT1 splice variants induced repression, but not the zinc-finger-deleted WT1 mutant, indicating dependence on DNA binding. A reporter construct with the IRF8 promoter was repressed by WT1, dependent on a putative WT1-response element. Binding of WT1 to the IRF8 promoter was demonstrated by chromatin immunoprecipitation. Our results identify IRF8 as a direct target gene for WT1 and provide a possible mechanism for oncogenic effects of WT1 in leukemia.
Leukemia 2010 May
PMID:Wilms' tumor gene 1 protein represses the expression of the tumor suppressor interferon regulatory factor 8 in human hematopoietic progenitors and in leukemic cells. 2023 5

We previously reported the adverse prognostic impact of Wilms tumor 1 gene (WT1) mutations in younger adult cytogenetically normal acute myeloid leukemia (CN-AML). Here, we investigated 243 older (> or = 60 years) primary CN-AML patients. WT1 mutated (WT1mut) patients (7%) had FLT3-ITD more frequently (P < .001), lower hemoglobin (P = .01), higher white blood cell count (P = .03) and percentage blood blasts (P = .03), and a shorter overall survival (P = .08) than WT1 wild-type (WT1wt) patients. Comparing older and younger WT1mut patients, they had similar pretreatment characteristics and outcome. By contrast, among WT1wt CN-AML, younger patients had a significantly better outcome. A WT1 mutation-associated gene-expression signature, reported here for the first time, included CD96, a leukemia stem cell-specific marker, and genes involved in gene regulation (eg, MLL, PML, and SNRPN) and in proliferative and metabolic processes (eg, INSR, IRS2, and PRKAA1), supporting the role of mutated WT1 in deregulating multiple homeostatic processes. Our results indicate that WT1mut CN-AML represents a distinct entity with poor treatment response across age groups. This study has been registered at www.clinicaltrials.gov as #NCT00900224.
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PMID:Mutations of the Wilms tumor 1 gene (WT1) in older patients with primary cytogenetically normal acute myeloid leukemia: a Cancer and Leukemia Group B study. 2044 68

The last decade has seen great strides in the field of cancer immunotherapy, especially the treatment of melanoma. Beginning with the identification of cancer antigens, followed by the clinical application of anti-cancer peptide vaccination, it has now been proven that adoptive T-cell therapy (ACT) using cancer antigen-specific T cells is the most effective option. Despite the apparent clinical efficacy of ACT, the timely preparation of a sufficient number of cancer antigen-specific T cells for each patient has been recognized as its biggest limitation. Currently, therefore, attention is being focused on ACT with engineered T cells produced using cancer antigen-specific T-cell receptor (TCR) gene transfer. With regard to human leukemia, ACT using engineered T cells bearing the leukemia antigen-specific TCR gene still remains in its infancy. However, several reports have provided preclinical data on TCR gene transfer using Wilms' tumor gene product 1 (WT1), and also preclinical and clinical data on TCR gene transfer involving minor histocompatibility antigen, both of which have been suggested to provide additional clinical benefit. In this review, we examine the current status of anti-leukemia ACT with engineered T cells carrying the leukemia antigen-specific TCR gene, and discuss the existing barriers to progress in this area.
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PMID:Application of adoptive T-cell therapy using tumor antigen-specific T-cell receptor gene transfer for the treatment of human leukemia. 2045 85

The aberrant overexpression of Wilms tumor 1 (WT1) in myeloid leukemia plays an important role in blast cell survival and resistance to chemotherapy. High expression of WT1 is also associated with relapse and shortened disease-free survival in patients. However, the mechanisms by which WT1 expression is regulated in leukemia remain unclear. Here, we report that heat shock protein 90 (Hsp90), which plays a critical role in the folding and maturation of several oncogenic proteins, associates with WT1 protein and stabilizes its expression. Pharmacologic inhibition of Hsp90 resulted in ubiquitination and subsequent proteasome-dependant degradation of WT1. RNAi-mediated silencing of WT1 reduced the survival of leukemia cells and increased the sensitivity of these cells to chemotherapy and Hsp90 inhibition. Furthermore, Hsp90 inhibitors 17-AAG [17-(allylamino)-17-demethoxygeldanamycin] and STA-9090 significantly reduced the growth of myeloid leukemia xenografts in vivo and effectively down-regulated the expression of WT1 and its downstream target proteins, c-Myc and Bcl-2. Collectively, our studies identify WT1 as a novel Hsp90 client and support the crucial role for the WT1-Hsp90 interaction in maintaining leukemia cell survival. These findings have significant implications for developing effective therapies for myeloid leukemias and offer a strategy to inhibit the oncogenic functions of WT1 by clinically available Hsp90 inhibitors.
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PMID:Heat shock protein 90 regulates the expression of Wilms tumor 1 protein in myeloid leukemias. 2065 Oct 72

T cells with specificity for antigens derived from Wilms Tumor gene (WT1), Proteinase3 (Pr3), and mucin1 (MUC1) have been demonstrated to lyse acute myeloid leukemia (AML) blasts and multiple-myeloma (MM) cells, and strategies to enhance or induce such tumor-specific T cells by vaccination are currently being explored in multiple clinical trials. To test safety and immunogenicity of a vaccine composed of WT1-, Pr3-, and MUC1-derived Class I-restricted peptides and the pan HLA-DR T helper cell epitope (PADRE) or MUC1-helper epitopes in combination with CpG7909 and MontanideISA51, four patients with AML and five with MM were repetitively vaccinated. No clinical responses were observed. Neither pre-existing nor naive WT1-/Pr3-/MUC1-specific CD8+ T cells expanded in vivo by vaccination. In contrast, a significant decline in vaccine-specific CD8+ T cells was observed. An increase in PADRE-specific CD4+ T helper cells was observed after vaccination but these appeared unable to produce IL2, and CD4+ T cells with a regulatory phenotype increased. Taken into considerations that multiple clinical trials with identical antigens but different adjuvants induced vaccine-specific T cell responses, our data caution that a vaccination with leukemia-associated antigens can be detrimental when combined with MontanideISA51 and CpG7909. Reflecting the time-consuming efforts of clinical trials and the fact that 1/3 of ongoing peptide vaccination trails use CpG and/or Montanide, our data need to be taken into consideration.
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PMID:Pitfalls of vaccinations with WT1-, Proteinase3- and MUC1-derived peptides in combination with MontanideISA51 and CpG7909. 2096 11

Wilms' tumor 1 (WT1) is a leukemia associated antigen (LAA) differentially expressed by leukemic blasts. Thus, WT1 may constitute a target for therapies such as those mediated by adoptive-specific T lymphocytes. Serological and cellular immune responses have been elicited by WT1 in patients with leukemia. Specific CD8+ T cells able to recognize this antigen can be selected by streptamers and then infused into leukemia patients. Potentially, these T cells could lyse leukemic blasts expressing WT1. The only good manufacturing practice-certified technology is streptamers, which are available for antigen-specific T-cell sorting. Immunocompromised patients may have their antigen-specific immune responses restored through the transfer of adoptive T cells specific for this LAA.
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PMID:Wilms' tumor 1 as a novel target for immunotherapy of leukemia. 2097 Jun 78


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