WT1 and immunotherapy

B-cell acute lymphoblastic leukemia (B-ALL) is a rare heterogeneous disease characterized by a block in lymphoid differentiation and a rapid clonal expansion of immature, non-functioning B cells. Adult B-ALL patients have a poor prognosis with less than 50% chance of survival after five years and a high relapse rate after allogeneic haematopoietic stem cell transplantation. Novel treatment approaches are required to improve the outcome for patients and the identification of B-ALL specific antigens are essential for the development of targeted immunotherapeutic treatments...

Recent advances in adoptive immunotherapy using cytotoxic T lymphocytes (CTLs) have led to moderate therapeutic anti-cancer effects in clinical trials. However, a critical issue, namely that CTLs collected from patients are easily exhausted during expansion culture, has yet to be solved. To address this issue, we have been developing a strategy which utilizes induced pluripotent stem cell (iPSC) technology. This strategy is based on the idea that when iPSCs are produced from antigen-specific CTLs, CTLs regenerated from such iPSCs should show the same antigen specificity as the original CTLs...

A National Cancer Institute consensus study on prioritization of cancer antigens ranked the Wilms tumor 1 (WT1) protein as the top immunotherapy target in cancer. We previously reported a pilot study of a multivalent WT1 peptide vaccine (galinpepimut-S) in acute myeloid leukemia (AML) patients. We have now conducted a phase 2 study investigating this vaccine in adults with AML in first complete remission (CR1). Patients received 6 vaccinations administered over 10 weeks with the potential to receive 6 additional monthly doses if they remained in CR1...

Thymic epithelial tumors are rare malignancies, and no optimal therapeutic regimen has been defined for patients with advanced disease. Patients with advanced thymic epithelial tumors, which were resistant or intolerable to prior therapies, were eligible for this study. Patients received 9 mer-WT1-derived peptide emulsified with Montanide ISA51 adjuvant via intradermal administration once a week as a monotherapy. After the 3-month-protocol treatment, the treatment was continued mostly at intervals of 2-4 weeks until disease progression or intolerable adverse events occurred...

Background: To develop cancer antigen-targeted immunotherapeutic strategies for malignant pleural mesothelioma (MPM), we investigated the individual and coexpressions of the cancer-associated antigens mesothelin (MSLN), cancer antigen 125 (CA125), and Wilms tumor 1 (WT1) in both epithelioid and non-epithelioid MPM. Methods: All available hematoxylin and eosin-stained slides from patients who were diagnosed with MPM (1989-2010) were reviewed. We constructed tissue microarrays from 283 patients (epithelioid = 234; non-epithelioid = 49)...

Despite the revolutionary progress of immune checkpoint inhibitors (CPIs) for cancer immunotherapy, CPIs are effective only in a subset of patients. Combining CPIs and cancer vaccines to achieve better clinical outcomes is a reasonable approach since CPI enhances cancer vaccine-induced tumor-associated antigen (TAA) specific CTL. Among the various TAAs so far identified, WT1 protein is one of the most promising TAAs as a cancer vaccine target. Until now clinical trials of WT1 vaccine have demonstrated only modest clinical efficacy...

Wilms' tumor 1 (WT1) expression has been investigated in various human cancers as a target molecule for cancer immunotherapy. However, few studies have focused on WT1 expression in dogs. Firstly, cDNA of canine WT1 (cWT1) was molecularly cloned from normal canine kidney. The cross-reactivity of the anti-human WT1 monoclonal antibody (6F-H2) with cWT1 was confirmed via Western blotting using cells overexpressing cWT1. Immunohistochemical staining revealed that cWT1 expression was detected in all canine lymphoma tissues and in some normal canine tissues, including the kidney and lymph node...

The advent of novel strategies to generate leukemia-associated-antigen (LAA)-specific T cells for adoptive immunotherapies creates a demand for standardized good laboratory practice (GLP)-compliant enumeration assays to provide a secure clinical environment-whether it is to identify potential donors, define therapeutic doses for transplantation, or monitor clinical success. Here, we introduce a no-wash assay based on single-platform cell enumeration and Streptamer staining to determine the Wilms' tumor antigen 1 (WT1)-specific T cell immunity in clinical samples...

The Wilms' tumor 1 (WT1) antigen is expressed in solid and hematological malignancies, but not healthy tissues, making it a promising target for cancer immunotherapies. Immunodominant WT1 epitopes, the native HLA-A2/WT1126-134 (RMFPNAPYL) (HLA-A2/RMFPNAPYL epitope (WT1A)) and its modified variant YMFPNAPYL (HLA-A2/YMFPNAPYL epitope (WT1B)), can induce WT1-specific CD8(+) T cells, although WT1B is more stably bound to HLA-A*02:01. Here, to further determine the benefits of those two targets, we assessed the naive precursor frequencies; immunogenicity and cross-reactivity of CD8(+) T cells directed toward these two WT1 epitopes...

The Wilms' tumor oncogene protein (WT1) is a highly validated tumor antigen for immunotherapy. WT1-targeted immunotherapy has been extensively explored in multiple human trials in various cancers. However, clinical investigations using WT1 epitopes have generally focused on two peptides, HLA-restricted to HLA-A*02:01 or HLA-A*24:02. The goal of this study was to identify new epitopes derived from WT1, to expand the potential use of WT1 as a target of immunotherapy. Using computer-based MHC-binding algorithms and in vitro validation of the T cell responses specific for the identified peptides, we found that a recently identified HLA-A*24:02-binding epitope (239-247), NQMNLGATL (NQM), was also a strong CD8+ T cell epitope for HLA-A*02:01 molecule...

Wilms' tumor 1 (WT1) is a promising target of new immunotherapies for acute myeloid leukemia (AML) as well as for other cancers. OCV-501 is a helper peptide derived from the WT1 protein. OCV-501 induced OCV-501-specific Type 1 T-helper (Th1) responses dose-dependently and stimulated helper activity of the specific Th1 cells in peripheral blood mononuclear cells from healthy donors. OCV-501 also enhanced the increase in WT1-killer peptide-specific cytotoxic T lymphocytes. OCV-501 stimulated the OCV-501-specific Th1 clones in an HLA class-II restricted manner and formed a complex with HLA class-II protein...

Several types of vaccine-delivering tumor-associated antigens (TAAs) have been developed in basic and clinical research. Wilms' tumor 1 (WT1), identified as a gene responsible for pediatric renal neoplasm, is one of the most promising TAA for cancer immunotherapy. Peptide and dendritic cell-based WT1 cancer vaccines showed some therapeutic efficacy in clinical and pre-clinical studies but as yet no oral WT1 vaccine can be administrated in a simple and easy way. In the present study, we constructed a novel oral cancer vaccine using a recombinant Bifidobacterium longum displaying WT1 protein...

AIM: In cancer immunotherapy, biomarkers are important for identification of responsive patients. This study was aimed to find biomarkers that predict clinical outcome of WT1 peptide vaccination. MATERIALS & METHODS: Candidate genes that were expressed differentially between long- and short-term survivors were identified by cDNA microarray analysis of peripheral blood mononuclear cells that were extracted from 30 glioblastoma patients (discovery set) prior to vaccination and validated by quantitative RT-PCR using discovery set and different 23 patients (validation set)...

Synthetic immunology based on rapidly-advancing gene-engineering and immunobiology has made novel anticancer adoptive immunotherapies, using gene-modified T lymphocytes to express cancer antigen-specific receptors, a reality. Various technological innovations have overcome recent difficulties and achieved clear and long-lasting clinical efficacy against tumors, while seeking more powerful effector gene-modified T cells has yielded serious treatment-related adverse events. In this article, along with introducing our clinical trial for a novel anti-leukemia adoptive immunotherapy regimen using gene-modified autologous lymphocytes to express leukemia antigen Wilms Tumor 1(WT1)-specific T cell receptor (TCR) against refractory acute myeloid leukemia (AML) and high-risk myelodysplastic syndrome (MDS), we provide an overview of the current status of this emerging treatment option and discuss its future form in the context of neoantigens encoded by mutated genes in cancer cells and immune checkpoint inhibitors...

CD19-directed chimeric antigen receptor (CAR) T cells are clinically effective in a limited set of leukemia patients. However, CAR T-cell therapy thus far has been largely restricted to targeting extracellular tumor-associated antigens (TAA). Herein, we report a T-cell receptor-mimic (TCRm) CAR, termed WT1-28z, that is reactive to a peptide portion of the intracellular onco-protein Wilms Tumor 1(WT1), as it is expressed on the surface of the tumor cell in the context of HLA-A*02:01. T cells modified to express WT1-28z specifically targeted and lysed HLA-A*02:01+ WT1+ tumors and enhanced survival of mice engrafted with HLA-A*02:01+, WT1+ leukemia or ovarian tumors...

Due to its immunogenicity and overexpression concomitant with leukemia progression, Wilms tumor protein 1 (WT1) is of particular interest for immunotherapy of AML relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT). So far, WT1-specific T-cell responses have mainly been induced by vaccination with peptides presented by certain HLA alleles. However, this approach is still not widely applicable in clinical practice due to common limitations of HLA restriction. Dendritic cell (DC) vaccines electroporated with mRNA encoding full-length protein have also been tested for generating WT1-derived peptides for presentation to T-cells...

We assessed the efficacy of WT1 class I peptide and WT1 class II peptide pulsed dendritic cell(DC)therapy for a wide range of advanced cancers. This retrospective study included 60 advanced cancer patients who were vaccinated 5times or more in this clinic between September 2013 and December 2015. The clinical response was examined. This treatment was approved by the ethics panel at this institution. Sixty patients were injected an average of 6.15times with dendritic cells(DCs) (2.6×10 / 7 cells/injection)...

Specific immunotherapy for acute leukemia remains a great unmet need. Native unmodified monoclonal antibody therapies, while promising, are inadequately effective for these malignancies, and multiple mechanisms for failure have been described. Antibody-dependent cellular cytotoxicity or phagocytosis is the primary modality of mAb-mediated cell killing in vivo, but ultimately leads to relapse of the leukemias, in model systems and in humans. By use of a T-cell receptor mimic mAb ESKM, derived against a WT1 peptide expressed in complex with HLA-A*02:01, whose only mechanism of therapeutic action is ADCC, we evaluated the mechanisms of leukemic relapse from its potent therapeutic action in mouse xenograft models of human leukemia...

We formerly demonstrated that vaccination with Wilms' tumor 1 (WT1)-loaded autologous monocyte-derived dendritic cells (mo-DCs) can be a well-tolerated effective treatment in acute myeloid leukemia (AML) patients. Here, we investigated whether we could introduce the receptor for hyaluronic acid-mediated motility (RHAMM/HMMR/CD168), another clinically relevant tumor-associated antigen, into these mo-DCs through mRNA electroporation and elicit RHAMM-specific immune responses. While RHAMM mRNA electroporation significantly increased RHAMM protein expression by mo-DCs, our data indicate that classical mo-DCs already express and present RHAMM at sufficient levels to activate RHAMM-specific T cells, regardless of electroporation...

Successful cancer immunotherapy necessitates T cell proliferation and infiltration into tumor without exhaustion, a process closely links optimal maturation of dendritic cells (DC), and adjuvant promotes this process as an essential prerequisite. Poly(I:C) has contributed to adjuvant immunotherapy that evokes an antitumor response through the Toll-loke receptor 3 (TLR3)/TICAM-1 pathway in DC. However, the mechanism whereby Poly(I:C) acts on DC for T cell proliferation and migration remains undetermined. Subcutaneous injection of Poly(I:C) regressed implant tumors (WT1-C1498 or OVA-EG7) in C57BL/6 mice, which coincided with tumor-infiltration of CD8(+) T cells...