Publications by authors named "Keiko Udaka"

Aim: Developing effective adjuvant therapies is essential for improving the surgical outcomes in patients with hepatocellular carcinoma (HCC). Immunotherapy against HCC has become a promising strategy; however, only approximately 30% of all HCC patients respond to immunotherapy. Previously, we generated the novel therapeutic vaccine comprising multi-human leukocyte antigen-binding heat shock protein 70/glypican-3 peptides with a novel adjuvant combination of hLAG-3Ig and poly-ICLC.

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Although the Omicron variant of the SARS-CoV-2 virus shows resistance to neutralizing antibody, it retains susceptibility to the cellular immune response. Here we characterize vaccine-induced T cells specific for various SARS-CoV-2 variants and identified HLA-A*24:02-restricted CD8 T cells that strongly suppress Omicron BA.1 replication in vitro.

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To develop combination immunotherapies for gastric cancers, immunologically well-characterized preclinical models are crucial. Here, we leveraged two transplantable murine gastric cancer cell lines, YTN2 and YTN16, derived from the same parental line but differing in their susceptibility to immune rejection. We established their differential sensitivity to immune checkpoint inhibitors (ICI) and identified neoantigens.

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Helper T lymphocytes (HTLs) play a central role in cancer immunity because they can not only help the induction and proliferation of cytotoxic T lymphocytes (CTLs) but also their differentiation into cytotoxic CD4 T cells and directly kill the target cells.This study describes the identification of three novel mouse Th epitope peptides, WT1, WT1 and WT1 derived from WT1 protein, which is the most potent tumor-associated antigen. Compared to immunization with WT1 CTL peptide alone, immunization with the addition of these WT1-specific Th peptides strongly induced WT1-specific CTLs, continued to maintain them, and efficiently rejected the challenge of WT1-expressing tumor cells.

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For the establishment of advanced medicines such as cancer immunotherapy, high performance carriers that precisely deliver biologically active molecules must be developed to target organelles of the cells and to release their contents there. From the viewpoint of antigen delivery, endosomes are important target organelles because they contain immune-response-related receptors and proteins of various types. To obtain carriers for precision endosome delivery, a novel type of polyamidoamine dendron-based lipid having pH-sensitive terminal groups was synthesized for this study.

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Background: This phase I study aimed to evaluate the safety, peptide-specific immune responses, and anti-tumor effects of a novel vaccination therapy comprising multi-HLA-binding heat shock protein (HSP) 70/glypican-3 (GPC3) peptides and a novel adjuvant combination of hLAG-3Ig and Poly-ICLC against metastatic gastrointestinal cancers.

Methods: HSP70/GPC3 peptides with high binding affinities for three HLA types (A*24:02, A*02:01, and A*02:06) were identified with our peptide prediction system. The peptides were intradermally administered with combined adjuvants on a weekly basis.

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Specificity analyses of peptide binding to human leukocyte antigen (HLA)-A molecules have been hampered due to a lack of proper monoclonal antibodies (mAbs) for certain allomorphs, such as the prevalent HLA-A1 for Caucasians and HLA-A11 for Asians. We developed a mAb that recognizes a conformational epitope common to most HLA-A allomorphs. The mAb, named A-1, does not discriminate peptides by amino acid sequences, making it suitable for measuring peptide binding.

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We previously found that heat-shock protein 70 (HSP70) is expressed on hepatocellular carcinoma cells and developed an HSP70 mRNA-transfected dendritic cell therapy for treating unresectable or recurrent hepatocellular carcinoma. The phase I trial was completed successfully. The purpose of this study is to identify a promiscuous epitope peptide derived from HSP70 for the purpose of developing a novel cancer peptide vaccine.

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The question of why we age and finally die has been a central subject in the life, medical, and health sciences. Many aging theories have proposed biomarkers that are related to aging. However, they do not have sufficient power to predict the aging process and longevity.

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Cancer vaccines have been developed as a new therapeutic approach, however, their clinical benefit remains limited. We previously performed a phase II study for advanced colorectal cancer (CRC) using five human leukocyte antigen (HLA-A*24:02)-restricted peptides derived from kinase of the outer chloroplast membrane 1, translocase of outer mitochondrial membrane 34 (TOMM34), ring finger protein 43 (RNF43), vascular endothelial growth factor receptor 1 (VEGFR1) and VEGFR2. In the present study the relationship between overall survival (OS) and several biomarkers, including cytotoxic T lymphocyte (CTL) and immunoglobulin G (IgG) responses to these five peptides, was investigated.

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IL-36, a newly named member of the IL-1 cytokine family, includes 3 isoforms, IL-36α, IL-36β, and IL-36γ, all of which bind to a heterodimer containing the IL-36 receptor (IL-36R). Little is known about the role of the IL-36 axis in acute kidney injury (AKI) pathogenesis. Therefore, we evaluated IL-36 function in the bilateral renal ischemia-reperfusion injury model of AKI using IL-36R knockout and wild-type mice.

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Imiquimod is an imidazoquinoline immune response modifier that is used in antiviral and antiallergic creams. Combination therapy using transcutaneous imiquimod and oral sorafenib was previously demonstrated to reduce the tumor burden of renal cell carcinoma growing cutaneously in a mouse model. In the present study, an orthotopic mouse model was used to investigate whether combined treatment with oral sorafenib and transcutaneous imiquimod inhibited renal cell carcinoma growing in the kidney.

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To establish peptide vaccine-based cancer immunotherapy, we investigated the improvement of antigenic peptides by encapsulation with pH-sensitive fusogenic polymer-modified liposomes for induction of antigen-specific immunity. The liposomes were prepared by modification of egg yolk phosphatidylcholine and l-dioleoyl phosphatidylethanolamine with 3-methyl-glutarylated hyperbranched poly(glycidol) (MGlu-HPG) and were loaded with antigenic peptides derived from ovalbumin (OVA) OVA-I (SIINFEKL), and OVA-II (PSISQAVHAAHAEINEAPA), which bind, respectively, to major histocompatibility complex (MHC) class I and class II molecules on dendritic cell (DCs). The peptide-loaded liposomes were taken up efficiently by DCs.

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Objectives: To investigate whether the combination of the imidazoquinoline immune response modifier, imiquimod, and the multitargeted tyrosine-kinase inhibitor, sorafenib, inhibits the growth of renal cell carcinoma in mice.

Methods: Female BALB/c mice were implanted subcutaneously with 2 × 10(5) RENCA mouse kidney cancer cells, and were treated with transcutaneously applied cream containing imiquimod and oral administrations of sorafenib beginning 5 days after implantation of the cells. Tumor incidence and burden were determined at 28 days after initiation of therapy.

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Class-switched memory B cells, which are generated through the processes of somatic hypermutation (SHM) and affinity-based selection in germinal centers, contribute to the production of affinity-matured IgG antibodies in the secondary immune response. However, changes in the affinity of IgM antibodies during the immune response have not yet been studied, although IgM(+) memory B cells have been shown to be generated. In order to understand the relationship between IgM affinity and the recall immune response, we prepared hybridomas producing anti-(4-hydroxy-3-nitrophenyl)acetyl (NP) IgM antibodies from C57BL/6 mice and from activation-induced cytidine deaminase (AID)-deficient mice.

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This study explored molecular mechanisms by which Bcr-Abl induced expression of Aurora kinase A and B (AURKA and AURKB) in chronic myeloid leukemia cells. Lentiviral transduction of Bcr-Abl into either Ba/F3 or CD34(+) hematopoietic stem/progenitor cells potently increased levels of AURKA and AURKB in association with phosphorylation of AKT and stimulated their proliferation. Bcr-Abl-mediated expression of AURKA and AURKB were decreased in CD34(+) HSPCs when AKT was inactivated by an shRNA against AKT, suggesting that Bcr-Abl induced expression of AURKA and AURKB via AKT signaling.

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We recently reported that adhesion molecule CD82 is aberrantly expressed in CD34(+) /CD38(-) leukemia stem cells (LSCs). Here, we report the results of a functional analysis of CD82 in CD34(+) /CD38(-) acute myelogenous leukemia (AML) cells. Short hairpin (sh)RNA-mediated downregulation of CD82 resulted in a decrease in the level of IL-10.

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We previously showed that Aurora kinase A (AURKA) is aberrantly expressed in acute myelogenous leukemia (AML) cells when compared to bone marrow mononuclear cells isolated from healthy volunteers. We have also shown that CD34(+) /CD38(-) AML cells, one of compartments enriched for leukemia stem cells in most leukemia subgroups, were relatively resistant to cytarabine-mediated growth inhibition when compared to their CD34(+) /CD38(+) counterparts. Our study attempted to identify therapeutic targets in CD34(+) /CD38(-) AML cells and found that CD34(+) /CD38(-) AML cells isolated from patients (n = 26) expressed larger amounts of AURKA than their CD34(+) /CD38(+) counterparts and CD34(+) normal hematopoietic stem/progenitor cells isolated from healthy volunteers (n = 6), as measured by real-time reverse-transcriptase polymerase chain reaction.

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Adult T-cell leukaemia-lymphoma (ATLL) is an aggressive malignancy of CD4(+)  CD25(+) T lymphocytes, characterized by a severely compromised immunosystem, in which the human T-cell lymphotropic virus type 1 (HTLV-1) has been recognized as the aetiological agent. This study found that an IκB kinase β (IKKβ) inhibitor Bay11-7082 inactivated mammalian target of rapamycin (mTOR), signal transducer and activator of transcription 3 and transcription factor nuclear factor-κB in HTLV-1-infected T cells; this was significantly enhanced in the presence of the mTOR inhibitor everolimus. In addition, Bay11-7082 decreased production of the immunosuppressive cytokine interleukin-10 (IL-10), which was further down-regulated when Bay11-7082 was combined with evelolimus in HTLV-1-infected T and ATLL cells isolated from patients.

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To identify molecular targets in leukemia stem cells (LSCs), this study compared the protein expression profile of freshly isolated CD34(+) /CD38(-) cells with that of CD34(+) /CD38(+) counterparts from individuals with acute myelogenous leukemia (n = 2, AML) using isobaric tags for relative and absolute quantitation (iTRAQ). A total of 98 proteins were overexpressed, while six proteins were underexpressed in CD34(+) /CD38(-) AML cells compared with their CD34(+) /CD38(+) counterparts. Proteins overexpressed in CD34(+) /CD38(-) AML cells included a number of proteins involved in DNA repair, cell cycle arrest, gland differentiation, antiapoptosis, adhesion, and drug resistance.

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Binding of short antigenic peptides to major histocompatibility complex (MHC) molecules is a core step in adaptive immune response. Precise identification of MHC-restricted peptides is of great significance for understanding the mechanism of immune response and promoting the discovery of immunogenic epitopes. However, due to the extremely high MHC polymorphism and huge cost of biochemical experiments, there is no experimentally measured binding data for most MHC molecules.

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We have recently established the MV4-11 acute myelogenous leukemia (AML) subline, designated as MV4-11 TP53 R248W, which possesses a missense mutation (CGG→TGG; R248W) in the TP53 gene, leading to inactivation of this transcription factor. DNA methyltransferase (DNMT) inhibitor 5-Aza-2'-deoxycytidine (5-AzadC) induced apoptosis in MV4-11, but not in MV4-11 TP53 R248W cells. Another class of anti-epigenetic agent histone deacetylase inhibitor (HDACI) inhibited the proliferation of both MV4-11 and MV4-11 TP53 R248W cells.

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As antigenic peptides binding to major histocompatibility complex (MHC) molecules is the prerequisite of cellular immune responses, an accurate computational predictor will be of great benefit to biologists and immunologists for understanding the underlying mechanism of immune recognition as well as facilitating the process of epitope mapping and vaccine design. Although various computational approaches have been developed, recent experimental results on benchmark data sets show that the development of improved predictors is needed, especially for MHC Class II peptide binding. To make the most of current methods and achieve a higher predictive performance, we developed a new web server, MetaMHC, to integrate the outputs of leading predictors by several popular ensemble strategies.

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The Wilms' tumor gene WT1 is overexpressed in various kinds of hematopoietic malignancies as well as solid cancers, and this protein has been demonstrated to be an attractive target antigen for cancer immunotherapy. WT1-specific CTL epitopes with a restriction of HLA-A 2402 or HLA-A 0201 have been already identified. In the present study it has been demonstrated that a 9-mer WT1-derived WT1(187) peptide, which had already been shown to elicit a WT1-specific CTL response with a restriction of HLA-A 0201, can also elicit a CTL response with a restriction of HLA-A 0206.

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