Eishi Ashihara

Kyoto Pharmaceutical University, Kioto, Kyōto, Japan

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Publications (180)647.22 Total impact

  • Eishi Ashihara, Tetsuya Takada, Taira Maekawa
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    ABSTRACT: The canonical Wnt/β-catenin pathway plays an important role in different developmental processes through the regulation of stem cell functions. In the activation of the canonical Wnt/β-catenin pathway, β-catenin protein is imported into the nucleus and activates transcription of target genes including cyclin D1 and c-myc. Aberrant activation of the Wnt/β-catenin pathway contributes to carcinogenesis and malignant behaviors, and Wnt signaling is essential for the maintenance of cancer stem cells. The canonical Wnt/β-catenin pathway has been investigated extensively as a target in cancer treatment and several specific inhibitors of this signaling pathway have been identified through high-throughput screening. In this review, the significance of the canonical Wnt/β-catenin pathway in hematological carcinogenesis and screening methods for specific inhibitors are discussed. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    Cancer Science 03/2015; DOI:10.1111/cas.12655 · 3.53 Impact Factor
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    ABSTRACT: Exosomes, the natural vehicles of various biological molecules, have been examined in several research fields including drug delivery. Although understanding of the biological functions of exosomes has increased, how exosomes are transported between cells remains unclear. We hypothesized that cell tropism is important for effective exosomal intercellular communication and that parental cells regulate exosome movement by modulating constituent exosomal molecules. Herein, we demonstrated the strong translocation of glioblastoma-derived exosomes (U251exo) into their parental (U251) cells, breast cancer (MDA-MB-231) cells, and fibrosarcoma (HT-1080). Furthermore, disruption of proteins of U251exo by enzymatic treatment did not affect their uptake. Therefore, we focused on lipid molecules of U251exo with the expectation that they are crucial for effective incorporation of U251exo by cancer cells. Phosphatidylethanolamine was identified as a unique lipid component of U251-MG cell-derived extracellular vesicles. From these results, valuable insight is provided into the targeting of U251exo to cancer cells, which will help to develop a cancer-targeted drug delivery system. Copyright © 2014. Published by Elsevier Inc.
    Biochemical and Biophysical Research Communications 12/2014; 456(3). DOI:10.1016/j.bbrc.2014.12.015 · 2.28 Impact Factor
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    ABSTRACT: Parathyroid hormone (PTH) stimulates hematopoiesis in mouse models. The involvement of osteoblasts in this process has been well investigated; however, the effects of PTH on human hematopoiesis and bone marrow mesenchymal stromal cells (BM-MSCs) are unclear. Here, we show that BM-MSCs contribute to the hematopoiesis-stimulating effects of PTH via upregulation of cadherin-11 (CDH11). When culture-expanded human BM-MSCs were stimulated with PTH, their ability to expand co-cultured CD34+ hematopoietic progenitor cells (HPCs) was enhanced. Furthermore, when PTH-treated BM-MSCs were subcutaneously implanted into NOD/SCID mice, the induction of hematopoietic cells was enhanced. Culture-expanded human BM-MSCs expressed CDH11, and the level of CDH11 expression increased following PTH stimulation. Depletion of CDH11 expression in BM-MSCs using small interfering RNA abolished the enhancement of HPC expansion by PTH-treated BM-MSCs. In lethally irradiated mice that underwent BM transplantation, CDH11 expression in BM-MSCs was higher and survival was better in PTH-treated mice than in control mice. The number of hematopoietic cells in BM and the number of red blood cells in peripheral blood were higher in PTH-treated mice than in control mice. Our results demonstrate that PTH stimulates hematopoiesis through promoting the upregulation of CDH11 expression in BM-MSCs, at least in part. PTH treatment may be an effective strategy to enhance the ability of BM-MSCs to support hematopoiesis. Stem Cells 2014
    Stem Cells 08/2014; 32(8). DOI:10.1002/stem.1701 · 7.70 Impact Factor
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    ABSTRACT: The freshwater planarian Dugesia japonica has a simple central nervous system (CNS) and can regenerate complete organs, even a functional brain. Recent studies demonstrated that there is a great variety of neuronal-related genes, specifically expressed in several domains of the planarian brain. We identified a planarian dat gene, named it D. japonica dopamine transporter (Djdat), and analyzed its expression and function. Both in situ hybridization and immunofluorescence revealed that localization of Djdat mRNA and protein was the same as that of D. japonica tyrosine hydroxylase (DjTH). Although, dopamine (DA) content in Djdat(RNAi) planarians was not altered, Djdat(RNAi) planarians showed increased spontaneous locomotion. The hyperactivity in the Djdat(RNAi) planarians was significantly suppressed by SCH23390 or sulpiride pretreatment, which are D1 or D2 receptor antagonists, respectively. These results suggest that planarians have a Djdat ortholog and the ability to regulate dopaminergic neurotransmission and association with spontaneous locomotion.
    Biochemical and Biophysical Research Communications 07/2014; 449(4):412–418. · 2.28 Impact Factor
  • Annals of the Rheumatic Diseases 06/2014; 73(Suppl 2):128-128. DOI:10.1136/annrheumdis-2014-eular.1017 · 9.27 Impact Factor
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    ABSTRACT: The freshwater planarian Dugesia japonica has a simple central nervous system (CNS) and can regenerate complete organs, even a functional brain. Recent studies demonstrated that there is a great variety of neuronal-related genes, specifically expressed in several domains of the planarian brain. We identified a planarian dat gene, named it D. japonica dopamine transporter (Djdat), and analyzed its expression and function. Both in situ hybridization and immunofluorescence revealed that localization of Djdat mRNA and protein was the same as that of D. japonicatyrosine hydroxylase (DjTH). Although, dopamine (DA) content in Djdat(RNAi) planarians was not altered, Djdat(RNAi) planarians showed increased spontaneous locomotion. The hyperactivity in the Djdat(RNAi) planarians was significantly suppressed by SCH23390 or sulpiride pretreatment, which are D1 or D2 receptor antagonists, respectively. These results suggest that planarians have a Djdat ortholog and the ability to regulate dopaminergic neurotransmission and association with spontaneous locomotion.
    Biochemical and Biophysical Research Communications 05/2014; 449(4). DOI:10.1016/j.bbrc.2014.05.059 · 2.28 Impact Factor
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    ABSTRACT: In clinical settings, serum antibody levels serve as markers of pathology. For example, antibodies related to autoimmune diseases are among the conventional targets in laboratory tests. Simple clinical tests can improve the efficacy of laboratory practice. This study describes a single-step, wash-free technique for optically detecting antibodies in human serum through the localized surface plasmon resonance (LSPR) of gold nanoparticles. As a proof-of-concept experiment, the amount of antibiotin dissolved in human serum was measured with a LSPR-based biosensor in a wash-free manner using a conventional 96-well microtiter plate and a plate reader. For an efficient surface modification of biosensors, zwitterionic copolymer was used as a scaffold on the gold nanoparticle surface to immobilize antigen and blocking reagent. Single-step, wash-free measurement of antibiotin in human serum was successfully achieved. In addition, nonspecific responses from serum contents were significantly reduced because both the copolymer and hydrophilic antigen reagent that we employed were composed of poly(ethylene oxide) spacer. Comparative experiments of the antigen-antibody reaction in serum to that in buffered solution revealed that serum is a favorable environment for the biological reaction. In conclusion, our gold-nanoparticle-based LSPR method may provide a rapid and simple way to measure the amount of antibody in serum quantitatively in clinical practice.
    Analytical and Bioanalytical Chemistry 04/2014; 406(18). DOI:10.1007/s00216-014-7833-5 · 3.58 Impact Factor
  • Annals of the Rheumatic Diseases 01/2014; 72(Suppl 3):A200-A200. DOI:10.1136/annrheumdis-2013-eular.640 · 9.27 Impact Factor
  • Wataru Fujii, Eishi Ashihara, Yutaka Kawahito
    Inflammation and Regeneration 01/2014; 34(3):124-128. DOI:10.2492/inflammregen.34.124
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    ABSTRACT: Myeloid-derived suppressor cells (MDSCs) are of myeloid origin and are able to suppress T cell responses. The role of MDSCs in autoimmune diseases remains controversial, and little is known about the function of MDSCs in autoimmune arthritis. In this study, we clarify that MDSCs play crucial roles in the regulation of proinflammatory immune response in a collagen-induced arthritis (CIA) mouse model. MDSCs accumulated in the spleens of mice with CIA when arthritis severity peaked. These MDSCs inhibited the proliferation of CD4(+) T cells and their differentiation into Th17 cells in vitro. Moreover, MDSCs inhibited the production of IFN-γ, IL-2, TNF-α, and IL-6 by CD4(+) T cells in vitro, whereas they promoted the production of IL-10. Adoptive transfer of MDSCs reduced the severity of CIA in vivo, which was accompanied by a decrease in the number of CD4(+) T cells and Th17 cells in the draining lymph nodes. However, depletion of MDSCs abrogated the spontaneous improvement of CIA. In conclusion, MDSCs in CIA suppress the progression of CIA by inhibiting the proinflammatory immune response of CD4(+) T cells. These observations suggest that MDSCs play crucial roles in the regulation of autoimmune arthritis, which could be exploited in new cell-based therapies for human rheumatoid arthritis.
    The Journal of Immunology 06/2013; 191(3). DOI:10.4049/jimmunol.1203535 · 5.36 Impact Factor
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    ABSTRACT: Here we describe how a F-probe incorporated into an endogenous protein by a chemical biology method revealed protein dynamics. By explicit determination of ligand-bound and unbound structures with X-ray crystallography, the quantitative comparison of the protein's dynamics in live cells and in vitro is presented. These results clearly demonstrated the greater conformational fluctuations of the intracellular protein, partially due to macromolecular crowding effects.
    Chemical Communications 03/2013; 49(27):2801-3. DOI:10.1039/c3cc39205h · 6.72 Impact Factor
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    ABSTRACT: In contrast to the definitive role of the transcription factor, CCAAT/Enhancer binding protein α (C/EBPα), in steady-state granulopoiesis, previous findings have suggested that granulopoiesis during emergency situations, such as infection, is dependent on C/EBPβ. In this study, a novel lentivirus-based reporter system was developed to elucidate the molecular switch required for C/EBPβ-dependency. The results demonstrated that two cyclic AMP responsive elements (CREs) in the proximal promoter region of C/EBPβ were involved in the positive regulation of C/EBPβ transcription during granulocyte-macrophage colony-stimulating factor (GM-CSF)-induced differentiation of bone marrow cells. In addition, the transcripts of CRE binding (CREB) family proteins were readily detected in hematopoietic stem/progenitor cells. CREB was upregulated, phosphorylated and bound to the CREs in response to GM-CSF stimulation. Retroviral transduction of a dominant negative CREB mutant reduced C/EBPβ mRNA levels and significantly impaired the proliferation/differentiation of granulocyte precursors, while a constitutively active form of CREB facilitated C/EBPβ transcription. These data suggest that CREB proteins are involved in the regulation of granulopoiesis via C/EBPβ upregulation.
    PLoS ONE 01/2013; 8(1):e54862. DOI:10.1371/journal.pone.0054862 · 3.53 Impact Factor
  • 01/2013; 39(9):565-570. DOI:10.5649/jjphcs.39.565
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    ABSTRACT: Sulforaphane (SFN), a naturally occurring member of the isothiocyanate family, is effective against various types of malignant tumor cells. We studied whether the combination of SFN and radiation would be more effective against osteosarcoma cells when compared to these treatments alone. LM8 murine osteosarcoma cells were cultured with various concentrations of SFN for 24 h and/or 2 Gy X-irradiation. The effects of individual and combination treatments on the number of cells, the cell cycle, cell proliferation-related factors and apoptosis were analyzed. The combination of SFN plus radiation had significantly greater antitumor effects than either treatment alone. Exposure to SFN increased the population of cells in the G2/M phase. Combination treatment resulted in a higher percentage of cells being in sub-G1 than did SFN alone. In addition, the combination of SFN and radiation effectively induced nuclear fragmentation and apoptotic bodies, as shown by DAPI staining. The combination of SFN and 2 Gy radiation increased the cleavage and activation of caspase-3 compared with SFN or radiation alone, as shown by western blotting. Although radiation alone increased the phosphorylation of ERK and Akt proteins, the combination of SFN and radiation induced suppression of ERK and Akt phosphorylation when compared with radiation alone. We found that SFN enhanced the radiosensitivity of LM8 murine osteosarcoma cells by inducing apoptosis through G2/M-phase arrest and by inhibiting ERK and Akt activation. These findings suggest that SFN can be used as a radiosensitizer for osteosarcomas.
    Oncology Reports 12/2012; 29(3). DOI:10.3892/or.2012.2195 · 2.19 Impact Factor
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    ABSTRACT: Zoledronic acid (ZOL), a third-generation bisphosphonate, inhibits bone resorption, as well as exhibiting direct antitumor activity. To date, however, the combined effects of ZOL and ionizing radiation (IR) have not been assessed in patients with soft tissue sarcoma. We have, therefore, assessed the combined effects of ZOL and IR in fibrosarcoma cells. HT1080 fibrosarcoma cells were treated with ZOL and/or IR, together or sequentially and the antitumor effects were assessed. We found that ZOL significantly enhanced IR-induced apoptosis, especially when cells were treated with ZOL followed by IR. We, therefore, assessed the detailed mechanism of sequential treatment with ZOL and IR. Cells in G2 and M phases, the most radiosensitive phases of the cell cycle, were not increased by low concentrations of ZOL. However, the levels of expression of Akt, ERK1/2 and NF-κB proteins, all of which are related to radioadaptive resistance, were increased within a short time after irradiation with 3 Gy, and this expression was inhibited by a low concentration of ZOL, which blocked the prenylation of small GTPases. This sequential treatment also increased the generation of reactive oxygen species (ROS). These results suggest that the combination of ZOL with IR may be beneficial in treating patients with soft tissue sarcoma.
    International Journal of Oncology 12/2012; 42(2). DOI:10.3892/ijo.2012.1735 · 2.77 Impact Factor
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    ABSTRACT: Background/Aims: Tumor cells produce a large amount of acidic metabolites due to their high metabolic condition. However, cytosolic pH (pH(c)) of tumor cells is identical to or even slightly higher than that of normal cells. To maintain pH(c) at a normal or higher level, tumor cells would have to have higher expression and/or activity of H(+) transporting systems than normal cells. The purpose of the present study was to identify effects of ethyl-isopropyl amiloride (EIPA, an inhibitor of Na(+)/H(+) exchanger (NHE)) on proliferation of human gastric cancer MKN28 cells. Methods: Effects of EIPA on proliferation, pH(c), [Cl(-)](c) and expression of proteins regulating cell cycle and MAPKs were studied in MKN28 expressing NHE exposed to EIPA for 48 h. Results: EIPA suppressed proliferation of MKN28 cells by causing G(0)/G(1) arrest without any significant effects on pH(c), but associated with reduction of [Cl(-)](c). Although EIPA alone had no effects on pH(c), EIPA co-applied with DIDS (an inhibitor of Cl(-)/HCO(3)(-) exchangers; i.e., anion exchanger (AE) and Na+-driven Cl(-)/HCO(3)(-) exchanger (NDCBE)) reduced pH(c), suggesting that DIDS-sensitive Cl(-)/HCO(3)(-) transporters such as AE and/or NDCBE keep pH(c) normal by stimulating HCO(3)(-) uptake coupled with Cl(-) release under an NHE-inhibited condition. EIPA-induced lowered [Cl(-)](c) up-regulated expression of p21associated with phosphorylation of MAPKs, suppressing proliferation associated with G(0)/G(1) arrest. Conclusions : EIPA suppressed proliferation of MKN28 cells through up-regulation of p21 expression via reduction of [Cl(-)](c) as a result from DIDS-sensitive Cl(-)/HCO(3)(-) exchanger-mediated compensation for keeping pH(c) normal under an NHE-inhibited condition. This is the first study revealing that an NHE inhibitor suppressed the proliferation of cancer cells by reducing [Cl(-)](c) but not pH(c).
    Cellular Physiology and Biochemistry 10/2012; 30(5):1241-1253. DOI:10.1159/000343315 · 3.55 Impact Factor
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    ABSTRACT: DJ-1/PARK7 has multiple functions as an antioxidant, an oncogene, and a molecular chaperone in vertebrates, and loss-of-function mutations in DJ-1 cause early onset of Parkinson's disease. However, the function of invertebrate DJ-1 remains unknown. In order to investigate the function of planarian DJ-1, we isolated the planarian DJ-1 gene Dugesia japonica DJ-1 (DjDJ-1) and analyzed its expression and function. In situ hybridization analysis revealed that DjDJ-1 mRNA was expressed throughout the body, including the central nervous system, cells surrounding the pharynx, and stem cells. Planarian DjDJ-1 protein exhibited antioxidant function, similar to human DJ-1, as evidenced by the fact that recombinant DjDJ-1 protein reduced reactive oxygen species and protected human neuroblastoma SH-SY5Y cells from cell death. In addition, dopaminergic neurons in DjDJ-1(RNAi) planarians became susceptible to 6-hydroxydopamine, a dopaminergic neurotoxin. These results suggest that planarians have a DJ-1 ortholog, which has conserved antioxidant and neuroprotective functions.
    Neuroscience Research 09/2012; 74(3-4). DOI:10.1016/j.neures.2012.09.003 · 2.15 Impact Factor
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    ABSTRACT: Granulopoiesis is tightly regulated to meet host demands during both "steady-state" and "emergency" situations, such as infections. The transcription factor CCAAT/enhancer binding protein β (C/EBPβ) plays critical roles in emergency granulopoiesis, but the precise developmental stages in which C/EBPβ is required are unknown. In this study, a novel flow cytometric method was developed that successfully dissected mouse bone marrow cells undergoing granulopoiesis into five distinct subpopulations (#1-5) according to their levels of c-Kit and Ly-6G expression. After the induction of candidemia, rapid mobilization of mature granulocytes and an increase in early granulocyte precursors accompanied by cell cycle acceleration was followed by a gradual increase in granulocytes originating from the immature populations. Upon infection, C/EBPβ was upregulated at the protein level in all the granulopoietic subpopulations. The rapid increase in immature subpopulations #1 and #2 observed in C/EBPβ knockout mice at 1 d postinfection was attenuated. Candidemia-induced cell cycle acceleration and proliferation of hematopoietic stem/progenitors were also impaired. Taken together, these data suggest that C/EBPβ is involved in the efficient amplification of early granulocyte precursors during candidemia-induced emergency granulopoiesis.
    The Journal of Immunology 09/2012; 189(9):4546-55. DOI:10.4049/jimmunol.1103007 · 5.36 Impact Factor
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    ABSTRACT: The BCR-ABL fusion oncoprotein accelerates differentiation and proliferation of myeloid cells during the chronic phase of chronic myeloid leukemia (CP-CML). Here, the role of CCAAT/enhancer binding protein β (C/EBPβ), a regulator for 'emergency granulopoiesis,' in the pathogenesis of CP-CML was examined. C/EBPβ expression was upregulated in Lineage(-) CD34(+) CD38(-) hematopoietic stem cells (HSCs) and myeloid progenitors isolated from bone marrow of patients with CP-CML. In EML cells, a mouse HSC line, BCR-ABL upregulated C/EBPβ, at least in part, through the activation of STAT5. Myeloid differentiation and proliferation induced by BCR-ABL was significantly impaired in C/EBPβ-deficient bone marrow cells in vitro. Mice that were transplanted with BCR-ABL-transduced C/EBPβ knockout bone marrow cells survived longer than mice that received BCR-ABL-transduced wild-type (WT) bone marrow cells. Significantly higher levels of leukemic stem cells were maintained in BCR-ABL-transduced C/EBPβ-deficient cells than in BCR-ABL-transduced WT cells. These results suggest that C/EBPβ is involved in BCR-ABL-mediated myeloid expansion. Further elucidation of the molecular mechanisms underlying the C/EBPβ-mediated stem cell loss might reveal a novel therapeutic strategy for eradication of CML stem cells.Leukemia advance online publication, 21 September 2012; doi:10.1038/leu.2012.258.
    Leukemia: official journal of the Leukemia Society of America, Leukemia Research Fund, U.K 09/2012; DOI:10.1038/leu.2012.258 · 9.38 Impact Factor

Publication Stats

2k Citations
647.22 Total Impact Points

Institutions

  • 2012–2015
    • Kyoto Pharmaceutical University
      • Laboratory of Clinical and Translational Physiology
      Kioto, Kyōto, Japan
  • 1992–2011
    • Kyoto Prefectural University of Medicine
      • • Division of Molecular Cell Physiology
      • • Department of Orthopaedics
      • • Department of Cardiovascular Medicine
      • • Division of Hematology and Oncology
      • • Department of Pediatrics
      Kioto, Kyōto, Japan
  • 2007–2008
    • Kyoto University
      • Department of Experimental Therapeutics
      Kioto, Kyōto, Japan
    • Akita University Hospital
      Akita, Akita, Japan
  • 1993
    • Shakaihoken Kobe Central Hospital
      Kōbe, Hyōgo, Japan