GRIM19 is involved in WT1 expression and epithelial-to-mesenchymal transition in adenomyotic lesions.

The epithelial-to-mesenchymal transition may play a role in adenomyosis. GRIM19 expression is downregulated in adenomyotic lesions, and the effects of this downregulation in adenomyosis remain relatively unclear. In this study, we aimed to explore whether aberrant GRIM19 expression is associated with the epithelial-to-mesenchymal transition in adenomyosis and found that the expression of both GRIM19 and WT1 was low, and epithelial-to-mesenchymal transition, which included significant changes in CDH1, CDH2 and KRT8 expression, occurred in adenomyotic lesions, as confirmed by Western blotting and quantitative real-time PCR. We provided novel insights into WT1 expression in adenomyosis, revealing that WT1 expression was increased in the endometrial glands of adenomyotic lesions by immunohistochemistry. In vitro, knockdown of GRIM19 expression by small interfering RNA (siRNA) promoted the proliferation, migration and invasion of Ishikawa cells, as measured by Cell Counting Kit-8, wound healing assay and Transwell assays. Western blotting and quantitative real-time PCR confirmed that WT1 expression increased and epithelial-to-mesenchymal transition was induced, including the upregulation of CDH2 and downregulation of CDH1 and KRT8after transfecting the GRIM19 siRNA to Ishikawa cells. Furthermore, WT1 expression was upregulated and epithelial-to-mesenchymal transition was observed, including downregulation of CDH1 and KRT8in GRIM19 gene-knockdown mice. Upregulation of Wt1 expression in the endometrial glands of Grim19 knockdown mice was also verified by immunohistochemistry. Taken together, these results reveal that low expression of GRIM19 in adenomyosis may upregulate WT1 expression and induce epithelial-to-mesenchymal transition in the endometria, providing new insights into the pathogenesis of adenomyosis.

A new peptide vaccine OCV-501: in vitro pharmacology and phase 1 study in patients with acute myeloid leukemia.

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. OCV-501-specific Th1 clones demonstrated significant OCV-501-specific cytolytic activity against OCV-501-pulsed B-lymphoblastoid cell line cells. Based on the pre-clinical results, phase 1 clinical trial was conducted. The result of this trial suggested that the subcutaneous administration of OCV-501 once weekly for 4 weeks at doses of 0.3, 1, and 3 mg in older patients with AML during complete remission was safe and well tolerated. The maximum tolerated dose was considered to be ≥3 mg. Of the nine subjects enrolled, neither relapse nor blast cells were observed during the study. Immunological responses were observed in OCV-501-specific delayed-type hypersensitivity test. This trial was registered at http://www.clinicaltrials.gov as NCT 01440920.

Enhancement of the antigen-specific cytotoxic T lymphocyte-inducing ability in the PMDC11 leukemic plasmacytoid dendritic cell line via lentiviral vector-mediated transduction of the caTLR4 gene.

The aim of the present study was to enhance the efficiency of leukemia immunotherapy by increasing the antigen-specific cytotoxic T lymphocyte-inducing ability of leukemia cells. The leukemic plasmacytoid dendritic cell line PMDC05 containing the HLA-A02/24 antigen, which was previously established in our laboratory (Laboratory of Hematology and Oncology, Graduate School of Health Sciences, Niigata University, Niigata, Japan), was used in the present study. It exhibited higher expression levels of CD80 following transduction with lentiviruses encoding the CD80 gene. This CD80-expressing PMDC05 was named PMDC11. In order to establish a more potent antigen-presenting cell for cellular immunotherapy of tumors or severe infections, PMDC11 cells were transduced with a constitutively active (ca) toll-like receptor 4 (TLR4) gene using the Tet-On system (caTLR4-PMDC11). CD8(+) T cells from healthy donors with HLA-A02 were co-cultured with mutant WT1 peptide-pulsed PMDC11, lipopolysaccharide (LPS)-stimulated PMDC11 or caTLR4-PMDC11 cells. Interleukin (IL)-2 (50 IU/ml) and IL-7 (10 ng/ml) were added on day three of culture. Priming with mutant WT1 peptide-pulsed PMDC11, LPS-stimulated PMDC11 or caTLR4-PMDC11 cells was conducted once per week and two thirds of the IL-2/IL-7 containing medium was replenished every 3-4 days. Immediately prior to the priming with these various PMDC11 cells, the cultured cells were analyzed for the secretion of interferon (IFN)-γ in addition to the percentage and number of CD8(+)/WT1 tetramer(+) T cells using flow cytometry. caTLR4-PMDC11 cells were observed to possess greater antigen-presenting abilities compared with those of PMDC11 or LPS-stimulated PMDC11 cells in a mixed leukocyte culture. CD8 T cells positive for the WT1 tetramer were generated following 3-4 weeks of culture and CD8(+)/WT1 tetramer+ T cells were markedly increased in caTLR4-PMDC11-primed CD8(+) T cell culture compared with PMDC11 or LPS-stimulated PMDC11-primed CD8(+) T cell culture. These CD8(+) T cells co-cultured with caTLR4-PMDC11 cells were demonstrated to secrete IFN-γ and to be cytotoxic to WT1-expressing target cells. These data suggested that the antigen-specific cytotoxic T lymphocyte (CTL)-inducing ability of PMDC11 was potentiated via transduction of the caTLR4 gene. The present study also suggested that caTLR4-PMDC11 cells may be applied as potent antigen-presenting cells for generating antigen-specific CTLs in adoptive cellular immunotherapy against tumors and severe viral infections.

Phase I pilot study of Wilms tumor gene 1 peptide-pulsed dendritic cell vaccination combined with gemcitabine in pancreatic cancer.

This study aimed to evaluate the feasibility of and immune response to Wilms tumor gene 1 (WT1) peptide-pulsed dendritic cell vaccination combined with gemcitabine (DCGEM) as a first-line therapy among patients with advanced pancreatic cancer. Ten HLA-A*2402 patients were treated with WT1 peptide-pulsed DC vaccination (1 × 10(7) cells) on days 8 and 22 and gemcitabine (1000 mg/m(2) ) on days 1, 8 and 15. Induction of a WT1-specific immune response was evaluated using the delayed-type hypersensitivity (DTH) skin test, interferon-γ enzyme-linked immunospot and HLA tetramer assays, along with assays for various immunological factors. DCGEM was well-tolerated, and the relative dose intensity of gemcitabine was 87%. Disease control associated with a low neutrophil/lymphocyte ratio was observed in all three patients with DTH positivity; it was also correlated with a low percentage of granulocytic myeloid derived suppressor cells in the pretreatment peripheral blood (P = 0.017). Patients with liver metastases and high levels of inflammatory markers such as C-reactive protein and interleukin-8 (IL-8) showed poor survival even though a WT1-specific immune response was induced in them. WT1 peptide-pulsed DCGEM is feasible and effective for inducing anti-tumor T-cell responses. Our results support future investigations for pancreatic cancer patients with non-liver metastases and favorable immunological conditions. This trial was registered with the University hospital Medical Information Network (UMIN) Clinical Trials Registry (http://www.umin.ac.jp/ctr/ number: UMIN-000004855).

T-cell responses directed against multiple HLA-A*0201-restricted epitopes derived from Wilms' tumor 1 protein in patients with leukemia and healthy donors: identification, quantification, and characterization.

PURPOSE: Antigens derived from the Wilms' tumor (WT1) protein, which is overexpressed in leukemias, are attractive targets for immunotherapy. Four HLA-A*0201-restricted WT1-derived epitopes have been identified: WT37, WT126, WT187, and WT235. We determined the natural immunogenecity of these antigens in patients with hematologic malignancies and healthy donor. EXPERIMENTAL DESIGN: To detect very low frequencies of WT1-specific CD8+ T cells, we used quantitative reverse transcription-PCR to measure IFN-gamma mRNA production by WT1 peptide-pulsed CD8+ T cells from 12 healthy donors, 8 patients with chronic myelogenous leukemia, 6 patients with acute myelogenous leukemia, and 8 patients with acute lymphoblastic leukemia. RESULTS: Responses were detected in 5 of 8 chronic myelogenous leukemia patients, 4 of 6 patients with acute myelogenous leukemia, and 7 of 12 healthy donors. No responses were detected in patients with acute lymphoblastic leukemia. The magnitude and extent of these CD8+ T-cell responses was greater in patients with myeloid leukemias than in healthy donors. Clonotypic analysis of WT1-specific CD8+ T cells directly ex vivo in one case showed that this naturally occurring population was oligoclonal. Using fluorescent peptide-MHC class I tetramers incorporating mutations in the alpha3 domain (D227K/T228A) that abrogate binding to the CD8 coreceptor, we were able to confirm the presence of high-avidity T-cell clones within the antigen-specific repertoire. CONCLUSION: The natural occurrence of high-avidity WT1-specific CD8+ T cells in the periphery could facilitate vaccination strategies to expand immune responses against myeloid leukemias.

DNA-binding dependent and independent functions of WT1 protein during human hematopoiesis.

The Wilms tumor gene 1 (WT1) encodes a zinc-finger-containing transcription factor highly expressed in immature hematopoietic progenitor cells. Overexpression and presence of somatic mutations in acute leukemia indicate a role for WT1 in the pathogenesis of leukemia. CD34+ progenitor cells were transduced with one splice variant of human WT1 without the KTS insert in the zinc-finger domain, WT1(+/-), and with a deleted mutant of WT1 lacking the entire zinc-finger region, WT1(delZ), thus incapable of binding DNA. We show that inhibition of erythroid colony formation and differentiation is absolutely dependent on the DNA-binding zinc-finger domain of WT1. Unexpectedly, however, WT1(delZ) was equally effective as wild type protein in the reduction of myeloid clonogenic growth as well as in stimulation of myeloid differentiation, as judged by the expression of cell surface CD11b. Expression of neither WT1(+/-) nor WT1(delZ) upregulated mRNA for the cdk inhibitor p21(Waf1/Cip1) or p27Kip1. Our results demonstrate that WT1 affects proliferation and differentiation in erythroid and myeloid cells by different molecular mechanisms, and suggest that mutations affecting the zinc-finger domain of WT1 could interfere with normal differentiation in the pathogenesis of leukemia.

In vitro stimulation with WT1 peptide-loaded Epstein-Barr virus-positive B cells elicits high frequencies of WT1 peptide-specific T cells with in vitro and in vivo tumoricidal activity.

The Wilms tumor protein (WT1) is overexpressed in most acute and chronic leukemias. To develop a practicable, clinically applicable approach for generation of WT1-specific T cells and to comparatively evaluate the immunogenicity of WT1 in normal individuals, we sensitized T cells from 13 HLA-A0201+ and 5 HLA-A2402+ donors with autologous EBV-transformed B cells or cytokine-activated monocytes, loaded with the HLA-A0201-binding WT1 peptides (126-134)RMFPNAPYL or (187-195)SLGEQQYSV or a newly identified HLA-A2402-binding WT1 peptide (301-310)RVPGVAPTL. WT1-specific T cells were regularly generated from each donor. T cells sensitized with peptide-loaded EBV-transformed B cells generated higher numbers of WT1-specific T cells than peptide-loaded cytokine-activated monocytes. Contrary to expectations, the frequencies of WT1 peptide-specific T cells were equivalent to those generated against individual highly immunogenic HLA-A0201-binding EBV peptides. Each of these T-cell lines specifically killed WT1+ leukemias and solid tumors in an HLA-restricted manner but did not lyse autologous or HLA-matched normal CD34+ hematopoietic progenitor cells or reduce their yield of colony-forming unit-granulocyte-macrophage (CFU-GM), burst-forming unit erythroid (BFU-E), or mixed colonies (CFU-mix). Furthermore, WT1 peptide-specific T cells after adoptive transfer into nonobese diabetic-severe combined immunodeficient mice bearing subcutaneous xenografts of WT1+ and WT1- HLA-A0201+ leukemias preferentially accumulated in and induced regressions of WT1+ leukemias that expressed the restricting HLA allele. Such cells are clinically applicable and may prove useful for adoptive cell therapy of WT1+ malignant diseases in humans.

WT1 activates a glomerular-specific enhancer identified from the human nephrin gene.

The glomerular filtration barrier separates the blood from the urinary space. Nephrin is a transmembrane protein that belongs to the immunoglobulin superfamily and is localized to the slit diaphragms that are a critical component of this filtration barrier. Mutations in the nephrin gene (NPHS1) lead to congenital Finnish nephropathy, whereas alterations in the level of nephrin expression have been identified in a wide range of acquired glomerular diseases. A 186-bp fragment from the human NPHS1 promoter is capable of directing podocyte-specific expression of a beta-galactosidase transgene when placed in front of a heterologous minimal promoter in transgenic mice. The Wilms tumor suppressor gene (WT1) is a zinc-finger-containing transcription factor that is coexpressed with NPHS1 in differentiated podocytes; gel shift binding assays demonstrate that a recombinant WT1 protein can bind and activate the 186-bp NPHS1 fragment in a sequence-specific manner. Taken together, these results suggest that WT1 may be required for regulation of the NPHS1 gene in vivo.

Antilung cancer effect of WT1-specific cytotoxic T lymphocytes.

We and other groups have recently reported that CTLs that specifically recognize a peptide derived from WT1 lyse leukemia cells in a HLA class I-restricted manner. Because WT1 is expressed in various solid tumors as well as in leukemic cells, we investigated whether WT1-specific CTLs can also inhibit the growth of lung cancer by examining their cytotoxic activity against lung cancer cell lines in vitro and their inhibitory effect on the growth of human lung cancer cells engrafted into nude mice. The WT1 transcript was detected in most of the lung cancer cell lines examined. A WT1-specific, HLA-A24-restricted CTL clone (designated TAK-1) exhibited cytotoxicity against lung cancer cell lines bearing HLA-A24 but did not lyse cells lacking this HLA. This suggests that the target antigen for TAK-1 on HLA-A24-positive lung cancer cells is the naturally processed WT1 peptide. Adoptive transfer of TAK-1 into nude mice that had been engrafted with a HLA-A24-positive lung cancer cell line resulted in inhibition of cancer cell growth and prolonged survival. These findings strongly suggest that WT1 is a universal tumor-associated antigen and that WT1-targeting immunotherapy offers a potentially effective treatment option for lung cancer as well as leukemia.