Researcher Database

SAKAI Ryuichi
Faculty of Fisheries Sciences Marine Life Science Marine Bioresources Chemistry
Professor

Researcher Profile and Settings

Affiliation

  • Faculty of Fisheries Sciences Marine Life Science Marine Bioresources Chemistry

Job Title

    Professor

Degree

  • Ph.D.

Research funding number

  • 20265721

Research Interests

  • Dysidea herbacea   Marine Natural Products chemistry   

Research Areas

  • Neuroscience / Neurochemistry/Neuropharmacology
  • Fisheries science / Fisheries chemistry

Education

  •        - 1992  University of Illinois at Urban  Graduate School, Division of Chemistry  japan
  •        - 1983  University of the Ryukyus  Faculty of Science  japan

Research Activities

Published Papers

MISC

  • 内舛肇, ENG Andrew, EKINS Merrick, HOOPER John, SWANSON Geoofrey T., 酒井隆一  日本水産学会大会講演要旨集  2014-  121  2014/03   [Not refereed] [Not invited]
  • SAKAI RYUICHI, SAKAI RYUICHI  トキシンシンポジウム予稿集  62nd-  89  2015/06   [Not refereed] [Not invited]
  • 藤田雅紀, 時田学幸, 石川高史, 酒井隆一  日本水産学会大会講演要旨集  2014-  121  2014/03   [Not refereed] [Not invited]
  • SAKAI RYUICHI, ICHIMORI DAICHI, ODA YUTA, FUJITA MASAKI, IMADA CHIAKI  マリンバイオテクノロジー学会大会講演要旨集  17th-  51  2015/05   [Not refereed] [Not invited]
  • 岸伶美, 酒井隆一  日本水産学会大会講演要旨集  2014-  173  2014/03   [Not refereed] [Not invited]
  • NAKAJIMA HIROYA, ATSUMI WATARU, NAKAMURA TAKANORI, FUJITA MASAKI, SAKAI RYUICHI  日本水産学会大会講演要旨集  2015-  178  2015/03   [Not refereed] [Not invited]
  • SAKAI RYUICHI, UCHIMASU HAJIME, TSUDA MASASHI, KUMAGAI KEIKO, AKAKABE MAI, FUJITA MASAKI  日本水産学会大会講演要旨集  2015-  141  2015/03   [Not refereed] [Not invited]
  • FUJITA MASAKI, SAKAI RYUICHI, ISE YUJI  日本水産学会大会講演要旨集  2015-  139  2015/03   [Not refereed] [Not invited]
  • Hideki Yamaguchi, Nachi Yoshida, Miho Takanashi, Miho Takanashi, Yuumi Ito, Yuumi Ito, Kiyoko Fukami, Kazuyoshi Yanagihara, Masakazu Yashiro, Ryuichi Sakai  PLoS ONE  9-  2014/01   [Not refereed] [Not invited]  
    Scirrhous gastric carcinoma (SGC) has the worst prognosis of all gastric cancers, owing to its rapid expansion by invasion and frequent peritoneal dissemination. Due to the increased proliferation of stromal fibroblasts (SFs) that occurs within SGC lesions and the peritoneal metastatic sites, SFs have been proposed to support the progression of this disease. However, the biological and molecular basis and the pathological role of the intercellular interaction between SGC cells and SFs remain largely unknown. In this study, we investigated the role of SFs in the invasion of the extracellular matrix (ECM) by SGC cells. When SGC cells were cocultured with SFs derived from SGC tissue on three-dimensional (3D) Matrigel, they were attracted together to form large cellular aggregates that invaded within the Matrigel. Time-lapse imaging revealed that this process was associated with extensive contraction and remodeling of the ECM. Immunofluorescence and biochemical analysis showed that SGC cells stimulate phosphorylation of myosin light chain and actomyosin-mediated mechanical remodeling of the ECM by SFs. By utilizing this assay system for inhibitor library screening, we have identified several inhibitors that potently suppress the cooperation between SGC cells and SFs to form the invasive structures. Among them, a Src inhibitor dasatinib impaired the interaction between SGC cells and SFs both in vitro and in vivo and effectively blocked peritoneal dissemination of SGC cells. These results indicate that SFs mediate mechanical remodeling of the ECM by SGC cells, thereby promoting invasion and peritoneal dissemination of SGC. © 2014 Yamaguchi et al.
  • Hideki Yamaguchi, Miho Takanashi, Miho Takanashi, Nachi Yoshida, Nachi Yoshida, Yuumi Ito, Yuumi Ito, Reiko Kamata, Kiyoko Fukami, Kazuyoshi Yanagihara, Ryuichi Sakai  Cancer Science  105-  528  -536  2014/01   [Not refereed] [Not invited]  
    Diffuse-type gastric carcinomas (DGC) exhibit more aggressive progression and poorer prognosis than intestinal-type and other gastric carcinomas. To identify potential therapeutic targets, we examined protein tyrosine phosphorylation in a panel of DGC and other gastric cancer cell lines. Protein tyrosine phosphorylation was significantly enhanced or altered in DGC cell lines compared with that in other gastric cancer cell lines. Affinity purification and mass spectrometry analysis of tyrosine-phosphorylated proteins identified Met as a protein that is preferentially expressed and phosphorylated in DGC cell lines. Unexpectedly, Met inhibitors blocked cell growth, Met downstream signaling and peritoneal dissemination in vivo in only a subset of cell lines that exhibited remarkable overexpression of Met. Likewise, only cell lines with overexpression of fibroblast growth factor receptor 2 (FGFR2) or phosphorylation of FRS2 were sensitive to an FGFR2 inhibitor. A Src inhibitor saracatinib impaired growth in cell lines that are insensitive to both Met and FGFR2 inhibitors. Saracatinib also effectively impaired peritoneal dissemination of Met-independent and FGFR2-independent SGC cells. Moreover, DGC cell lines exhibited nearly mutually exclusive susceptibility to Met, FGFR and Src inhibitors. These results suggest that DGC have distinct sensitivities to molecular target drugs and that targeting Src is beneficial in the treatment of DGC insensitive to Met and FGFR inhibition. © 2014 The Authors.
  • Takamasa Uekita, Takamasa Uekita, Satoko Fujii, Yuri Miyazawa, Reika Iwakawa, Mako Narisawa-Saito, Katsuhiko Nakashima, Koji Tsuta, Hitoshi Tsuda, Tohru Kiyono, Jun Yokota, Ryuichi Sakai  Molecular Cancer Research  12-  1449  -1459  2014/01   [Not refereed] [Not invited]  
    ©2014 AACR. Involvement of Ras in cancer initiation is known, but recent evidence indicates a role in cancer progression, including metastasis and invasion; however, the mechanism is still unknown. In this study, it was determined that human lung cancer cells with Ras mutations, among other popular mutations, showed significantly higher expression of CUB domain-containing protein 1 (CDCP1) than those without. Furthermore, activated Ras clearly induced CDCP1, whereas CDCP1 knockdown or inhibition of CDCP1 phosphorylation by Src-directed therapy abrogated anoikis resistance, migration, and invasion induced by activated-Ras. Activation of MMP2 and secretion of MMP9, in a model of Ras-induced invasion, was found to be regulated through induction of phosphorylated CDCP1. Thus, CDCP1 is required for the functional link between Ras and Src signaling during the multistage development of human malignant tumors, highlighting CDCP1 as a potent target for treatment in the broad spectrum of human cancers associated with these oncogenes.
  • Takuya Shirakihara, Tomonori Kawasaki, Akihiko Fukagawa, Kentaro Semba, Ryuichi Sakai, Kohei Miyazono, Keiji Miyazawa, Masao Saitoh  Cancer Science  104-  1189  -1197  2013/09   [Not refereed] [Not invited]  
    Epithelial-mesenchymal transition (EMT) is a crucial event in wound healing, tissue repair, and cancer progression in adult tissues. Transforming growth factor (TGF)-β induces EMT in mouse epithelial cells. During prolonged treatment, TGF-β successively induces myofibroblastic differentiation with increased expression of myofibroblast marker proteins, including smooth muscle α actin and calponin. We recently showed that fibroblast growth factor-2 prevented myofibroblastic differentiation induced by TGF-β, and transdifferentiated the cells to those with much more aggressive characteristics (enhanced EMT). To identify the molecular markers specifically expressed in cells undergoing enhanced EMT induced by the combination of TGF-β and fibroblast growth factor-2, we carried out a microarray-based analysis and found that integrin α3 (ITGA3) and Ret were upregulated. Intriguingly, ITGA3 was also overexpressed in breast cancer cells with aggressive phenotypes and its expression was correlated with that of δEF-1, a key regulator of EMT. Moreover, the expression of both genes was downregulated by U0126, a MEK 1/2 inhibitor. Therefore, ITGA3 is a potential marker protein for cells undergoing enhanced EMT and for cancer cells with aggressive phenotypes, which is positively regulated by δEF-1 and the MEK-ERK pathway. © 2013 Japanese Cancer Association.
  • Masato Kasuga, Kohjiro Ueki, Naoko Tajima, Mitsuhiko Noda, Ken Ohashi, Hiroshi Noto, Atsushi Goto, Wataru Ogawa, Ryuichi Sakai, Shoichiro Tsugane, Nobuyuki Hamajima, Hitoshi Nakagama, Kazuo Tajima, Kohei Miyazono, Kohzoh Imai  Cancer Science  104-  965  -976  2013/07   [Not refereed] [Not invited]  
    In recent years, diabetes has been shown to be associated with cancer risk, and this has led to a joint committee being formed, enlisting experts from the Japan Diabetes Society and the Japanese Cancer Association to address this issue. Epidemiological data in Japan provides evidence to demonstrate that diabetes is associated with increased risk for cancers, especially colorectal, liver, and pancreatic cancers. The mechanisms through which diabetes is assumed to promote oncogenesis include insulin resistance and associated hyperinsulinemia, hyperglycemia, and inflammation. Common risk factors for type 2 diabetes and cancer include aging, male sex, obesity, physical inactivity, inappropriate diet (excessive red/processed meat intake, inadequate vegetable/fruit/dietary fiber intake), excessive alcohol drinking, and smoking. Given that inappropriate diet/exercise, smoking and excessive alcohol drinking are common risk factors for diabetes and cancer, diet/exercise therapy, smoking cessation and alcohol moderation may be associated with decreased risk for cancer in diabetic patients. There is as yet limited evidence as to whether any particular antidiabetic agents may influence cancer risk. © 2013 The Japanese Cancer Association and the Japan Diabetes Society.
  • Takamasa Uekita, Satoko Fujii, Yuri Miyazawa, Akinori Hashiguchi, Hitosi Abe, Michiie Sakamoto, Ryuichi Sakai  Cancer Science  104-  865  -870  2013/07   [Not refereed] [Not invited]  
    CUB (C1r/C1s, urchin embryonic growth factor, BMP1) domain-containing protein 1 (CDCP1) has been implicated in promoting metastasis of cancer cells through several mechanisms, including the inhibition of anoikis, which is cell death triggered by the loss of extracellular matrix interactions. However, the mechanism inhibiting cell death regulated by CDCP1 remains elusive. Inhibition of CDCP1 expression using small interfering RNA (siRNA) induced the cell death of suspended cancer cells without cleaving caspase-3, a marker of apoptosis; cell death was not inhibited by a general caspase inhibitor, suggesting that the loss of CDCP1 induces caspase-independent cell death. In contrast, knockdown of CDCP1 as well as protein kinase Cδ (PKCδ), a downstream effector of CDCP1, in a suspension culture of lung cancer cells resulted in marked induction of membranous microtubule-associated protein 1 light chain 3 (LC3)-II protein, a hallmark of autophagy, and caused the formation of an autophagosome structure visualized using green fluorescent protein-tagged LC3-II. Expression and phosphorylation of exogenous CDCP1 by Fyn kinase reduced the formation of autophagosomes and inhibited phosphorylation of CDCP1 by PP2, a Src kinase inhibitor or inhibited PKCδ by rottlerin, stimulating autophagosome formation. Moreover, death of suspended lung cancer cells induced by CDCP1 siRNA or by PKCδ siRNA was reduced by the autophagy inhibitor 3-methyladenine. These results indicate that CDCP1-PKCδ signaling plays a critical role in inhibiting autophagy, which is responsible for anoikis resistance of lung cancer cells. © 2013 Japanese Cancer Association.
  • M. Kasuga, K. Ueki, N. Tajima, M. Noda, K. Ohashi, H. Noto, A. Goto, W. Ogawa, R. Sakai, S. Tsugane, N. Hamajima, H. Nakagama, K. Tajima, K. Miyazono, K. Imai  Journal of the Japan Diabetes Society  56-  374  -390  2013/06   [Not refereed] [Not invited]
  • Yuri Miyazawa, Takamasa Uekita, Yuumi Ito, Yuumi Ito, Motoharu Seiki, Hideki Yamaguchi, Ryuichi Sakai  Molecular Cancer Research  11-  628  -637  2013/06   [Not refereed] [Not invited]  
    Complement C1r/C1s, Uegf, Bmp1 (CUB) domain-containing protein 1 (CDCP1) is a transmembrane protein that regulates anchorage-independent growth and cancer cell migration and invasion. Expression of CDCP1 is detected in a number of cancer cell lines and tissues and is closely correlated with poor prognosis. Invadopodia are actin-based protrusions on the surface of invasive cancer cells that promote the degradation of the extracellular matrix (ECM) via localized proteolysis, which is mainly mediated by membrane type 1 matrix metalloproteinase (MT1-MMP). MT1-MMP is accumulated at invadopodia by targeted delivery via membrane trafficking. The present study shows that CDCP1 is required for ECM degradation by invadopodia in human breast cancer and melanoma cells. CDCP1 localized to caveolin-1 - containing vesicular structures and lipid rafts and was detected in close proximity to invadopodia. Further biochemical analysis revealed that substantial amounts of CDCP1 existed in the Triton X-100 insoluble lipid raft fraction. CDCP1 was coimmunoprecipitated with MT1-MMP and colocalized with MT1-MMP at the vesicular structures. The siRNA-mediated knockdown of the CDCP1 expression markedly inhibited MT1-MMP - dependent ECM degradation and Matrigel invasion and reduced the accumulation of MT1-MMP at invadopodia, as shown by immunofluorescence analysis. These results indicate that CDCP1 is an essential regulator of the trafficking and function of MT1-MMP- and invadopodia-mediated invasion of cancer cells. © 2013 American Association for Cancer Research.
  • 上田拓弥, FREYMANN DM, FOCIAL PJ, 中村友香, SMITH Caleb, 井上昌, 尾島孝男, 松永智子, SWANSON GT, 酒井隆一  日本水産学会大会講演要旨集  2013-  102  2013/03   [Not refereed] [Not invited]
  • OYAGI YU, SASAKI SHINGO, SUZUKI HIROTO, OUCHI HITOSHI, INAI MAKOTO, ASAKAWA TOMOHIRO, SAKAI RYUICHI, SHIMAMOTO KEIKO, HAMASHIMA YOSHITAKA, KAN TOSHIYUKI  日本薬学会年会要旨集(CD-ROM)  135th-  ROMBUNNO.26G-AM07S  2015   [Not refereed] [Not invited]
  • SASAKI SHINGO, SUZUKI HIROTO, OUCHI HITOSHI, ASAKAWA TOMOHIRO, INAI MAKOTO, SAKAI RYUICHI, SHIMAMOTO KEIKO, HAMASHIMA YOSHITAKA, KAN TOSHIYUKI  反応と合成の進歩シンポジウム講演要旨集  40th-  109  2014/10   [Not refereed] [Not invited]
  • 松永智子, 酒井隆一  日本水産学会大会講演要旨集  2013-  96  2013/03   [Not refereed] [Not invited]
  • 境倫宏, 田中健斗, 石川裕一, 酒井隆一, 及川雅人  日本化学会講演予稿集  93rd-  (4)  1220  2013/03   [Not refereed] [Not invited]
  • Mitsuru Jimbo, Yuya Suda, Kazuhiko Koike, Sachiko Nakamura-Tsuruta, Sachiko Nakamura-Tsuruta, Junko Kominami, Junko Kominami, Masugu Kamei, Jun Hirabayashi, Jun Hirabayashi, Ryuichi Sakai, Hisao Kamiya  Journal of Experimental Marine Biology and Ecology  439-  129  -135  2013/01   [Not refereed] [Not invited]  
    We previously demonstrated that the lectin SLL-2, isolated from the octocoral Sinularia lochmodes, binds to the symbiotic microalgae Symbiodinium within the coral. Upon binding SLL-2, Symbiodinium cells transform from a flagellated swimming form into a non-flagellated coccoid form, the latter morphologically similar to the symbiotic stage found in corals. However, the site recognized by the lectin on the surface of Symbiodinium cells and the transformation mechanism have yet to be elucidated. We found that the ability of SLL-2 to induce the morphological change in Symbiodinium cells can be attenuated by pretreating the cells with glycosidases or by adding the SLL-2 binding inhibitor N-acetyl-. d-galactosamine to the culture medium. These results suggest that d-galactose-containing glycoconjugates on the Symbiodinium cell surface are the key ligand through which SLL-2 induces morphological transformation. We also found that SLL-2 binds with high affinity to the Forssman antigen, and masking the binding site on Symbiodinium cells by addition of anti-Forssman glycosphingolipid antibody inhibits the binding of SLL-2 to the cells. The antibody itself or other Forssman antigen-binding proteins, such as Helix pomatia agglutinin, can transform Symbiodinium cells into the coccoid stage in the absence of SLL-2. A neutral lipid fraction prepared from cultured Symbiodinium cells reacted with the anti-Forssman glycosphingolipid antibody, supporting the hypothesis that a Forssman antigen-like glycosphingolipid on the surface of Symbiodinium cells is involved in their morphological transformation induced by the lectin SLL-2. © 2012 Elsevier B.V.
  • UNNO Masaki, SASAKI Makoto, SAKAI Ryuichi, IKEDA SAITO Masao  X-RAYS  54-  (6)  338  -344  2012/12   [Not refereed] [Not invited]  
    Kainate receptors (KARs) are members of the ionotropic glutamate receptors (iGluR) that play variety of roles in the mammalian brain. Because KARs are comprised of five different isoform proteins, isoform selective compounds are indispensable tools in physiological researches. Dysiherbaine (DH) and neodysiherbaine A (NDH), natural toxins found from marine sponges, were shown to be potent and isoform-selective agonists for KARs. To understand structure-activity relationship of DH and NDH, numbers of analogues are synthesized, and their pharmacological activities have been evaluated in detail. Here, we determined the crystal structures of human KAR isoforms, GluK1 and GluK2, ligand-binding domain in complex with the DH analogues at high resolution. From these structures, we elucidated the relationships between the binding affinity and the molecular structure of the compounds. We also demonstrated differential recognition by some of the DH analogues of closely related isoforms GluK1 and GluK2. Further, we found that neither degree of the domain closure nor twist motion of domains directly correlated to agonist efficacy of the ligands.
  • UNNO MASAKI, SASAKI MAKOTO, SAKAI RYUICHI, SAITO MASAO  日本結晶学会誌  54-  (6)  338  -344  2012/12   [Not refereed] [Not invited]
  • Masato Oikawa, Shota Sasaki, Michihiro Sakai, Yuichi Ishikawa, Ryuichi Sakai  European Journal of Organic Chemistry  5789  -5802  2012/10   [Not refereed] [Not invited]  
    The syntheses of the marine sponge-derived γ-amino carboxylic acid dysibetaine CPa and five analogs in their racemic forms were successfully performed by taking advantage of an electron-withdrawing N-(4-nitrophenyl) group in the cyclopropanation reaction, the reductive ring opening of an imide, and the ethanolysis of an N-Boc-protected imide. © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
  • 神保充, 國谷奈美, 武内良太, 田中浩士, 高橋孝志, 小池一彦, 酒井隆一, 神谷久男  日本水産学会大会講演要旨集  2012-  79  2012/09   [Not refereed] [Not invited]
  • OTSUKA KAZUNORI, ISHIKAWA YUICHI, TAKAMIZAWA SATOSHI, SAKAI RYUICHI, OIKAWA MASATO  日本化学会講演予稿集  94th-  (4)  1468  2014/03   [Not refereed] [Not invited]
  • 境倫宏, 佐々木翔太, 石川裕一, 酒井隆一, SWANSON G.T., 及川雅人  日本化学会講演予稿集  92nd-  (4)  1182  2012/03   [Not refereed] [Not invited]
  • 喜田昭子, 神保充, 酒井隆一, 森本幸生, 武内良太, 田中浩士, 高橋孝志, 高橋孝志, 三木邦夫  KURRI KR  (193)  67  -70  2014/01   [Not refereed] [Not invited]
  • NAKAJIMA HIROYA, ATSUMI WATARU, FUJITA MASAKI, SAKAI RYUICHI  日本水産学会北海道支部大会講演要旨集  2014-  41  2014   [Not refereed] [Not invited]
  • 菅俣祐太郎, 常盤一弥, 加曽利祐基, 片山理佐, 村上悦子, 石川裕一, 酒井隆一, 及川雅人  日本化学会講演予稿集  92nd-  (4)  1181  2012/03   [Not refereed] [Not invited]
  • 神保充, 國谷奈美, 竹内亮太, 谷本典加, 田中千瑛, 山下洋, 小池一彦, 酒井隆一  日本動物学会大会予稿集  84th-  100  2013/08   [Not refereed] [Not invited]
  • 酒井隆一  日本薬学会年会要旨集  132nd-  (1)  175  2012/03   [Not refereed] [Not invited]
  • 藤田雅紀, 中野宏治, 酒井隆一  日本水産学会大会講演要旨集  2013-  100  2013/03   [Not refereed] [Not invited]
  • Takamasa Uekita, Ryuichi Sakai  Cancer Science  102-  1943  -1948  2011/11   [Not refereed] [Not invited]  
    Tumor metastasis is a complex multistep process by which cells from the primary tumor invade tissues, move through the vasculature, settle at distant sites and eventually grow to form secondary tumors. Altered tyrosine phosphorylation signals in cancer cells contribute to a number of aberrant characteristics involved in tumor invasion and metastasis. CUB domain-containing protein 1 (CDCP1) is a substrate of Src family kinases and has been shown to regulate anoikis resistance, migration and matrix degradation during tumor invasion and metastasis in a tyrosine phosphorylation-dependent manner. Knockdown of CDCP1 blocks tumor metastasis or peritoneal dissemination in vivo, without significantly affecting cell proliferation. Moreover, expression levels of CDCP1 are of prognostic value in several cancers. Here, we summarize the studies on CDCP1, focusing on structure and signal transduction, to gain insight into its role in cancer progression. Understanding the signaling pathways regulated by CDCP1 could help establish novel therapeutic strategies against the progression of cancer. © 2011 Japanese Cancer Association.
  • 上田拓弥, 井上昌, 中村友香, 松永智子, 尾島孝男, SWANSON Geffrey T., 酒井隆一  日本水産学会大会講演要旨集  2011-  115  2011/09   [Not refereed] [Not invited]
  • 松永智子, 酒井隆一, GILL Martin B., LASH‐VAN WYHE L. Leanne, SWANSON Geoffrey T.  天然有機化合物討論会講演要旨集  53rd-  409-413  -413  2011/09   [Not refereed] [Not invited]
  • 境倫宏, 佐々木翔太, 石川裕一, 酒井隆一, SWANSON G. T., 及川雅人  天然有機化合物討論会講演要旨集  53rd-  643-648  -648  2011/09   [Not refereed] [Not invited]
  • 常盤一弥, 菅俣祐太郎, 石川裕一, 酒井隆一, 及川雅人  日本化学会講演予稿集  92nd-  (4)  1180  2012/03   [Not refereed] [Not invited]
  • Masato Oikawa, Shota Sasaki, Michihiro Sakai, Ryuichi Sakai  Tetrahedron Letters  52-  4402  -4404  2011/08   [Not refereed] [Not invited]  
    The cyclopropane-containing amino acid, dysibetaine CPa, isolated from Micronesian marine sponge, has been synthesized in 4.53% total yield over 12 steps starting from maleic anhydride to study the biological function in detail, by taking advantage of electron-withdrawing 4-nitrophenyl group. © 2011 Elsevier Ltd. All rights reserved.
  • Hideki Yamaguchi, Hideki Yamaguchi, Hideki Yamaguchi, Shuhei Yoshida, Emi Muroi, Emi Muroi, Nachi Yoshida, Nachi Yoshida, Masahiro Kawamura, Zen Kouchi, Yoshikazu Nakamura, Ryuichi Sakai, Kiyoko Fukami  Journal of Cell Biology  193-  1275  -1288  2011/06   [Not refereed] [Not invited]  
    Invadopodia are extracellular matrix-degrading protrusions formed by invasive cancer cells that are thought to function in cancer invasion. Although many invadopodia components have been identified, signaling pathways that link extracellular stimuli to invadopodia formation remain largely unknown. We investigate the role of phosphoinositide 3-kinase (PI3K) signaling during invadopodia formation. We find that in human breast cancer cells, both invadopodia formation and degradation of a gelatin matrix were blocked by treatment with PI3K inhibitors or sequestration of D-3 phosphoinositides. Functional analyses revealed that among the PI3K family proteins, the class I PI3K catalytic subunit p110α, a frequently mutated gene product in human cancers, was selectively involved in invadopodia formation. The expression of p110α with cancerous mutations promoted invadopodiamediated invasive activity. Furthermore, knockdown or inhibition of PDK1 and Akt, downstream effectors of PI3K signaling, suppressed invadopodia formation induced by p110α mutants. These data suggest that PI3K signaling via p110α regulates invadopodia-mediated invasion of breast cancer cells.
  • Chikako Ozeki, Chikako Ozeki, Chikako Ozeki, Yuichiro Sawai, Yuichiro Sawai, Tatsuhiro Shibata, Takashi Kohno, Koji Okamoto, Koji Okamoto, Jun Yokota, Fumio Tashiro, Sei Ichi Tanuma, Ryuichi Sakai, Tatsuya Kawase, Tatsuya Kawase, Issay Kitabayashi, Yoichi Taya, Yoichi Taya, Rieko Ohki, Rieko Ohki, Rieko Ohki  Journal of Biological Chemistry  286-  18251  -18260  2011/05   [Not refereed] [Not invited]  
    The common polymorphism of p53 at codon 72, either encoding proline or arginine, has drawn attention as a genetic factor associated with clinical outcome or cancer risk for the last 2 decades. We now show that these two polymorphic variants differ in protein structure, especially within the N-terminal region and, as a consequence, differ in post-translational modification at the N terminus. The arginine form (p53-72R) shows significantly enhanced phosphorylation at Ser-6 and Ser-20 compared with the proline form (p53-72P). We also show diminished Mdm2-mediated degradation of p53-72R compared with p53-72P, which is at least partly brought about by higher levels of phosphorylation at Ser-20 in p53-72R. Furthermore, enhanced p21 expression in p53-72R-expressing cells, which is dependent on phosphorylation at Ser-6, was demonstrated. Differential p21 expression between the variants was also observed upon activation of TGF-β signaling. Collectively, we demonstrate a novel molecular difference and simultaneously suggest a difference in the tumor-suppressing function of the variants. © 2011 by The American Society for Biochemistry and Molecular Biology, Inc.
  • 櫻田剛史, GILL Martin B., FRAUSTO Shanti, COPITS Bryan, 野口恵一, 島本啓子, SWANSON Geoffrey T., 酒井隆一  日本水産学会大会講演要旨集  2011-  91  2011/03   [Not refereed] [Not invited]
  • 松永智子, 酒井隆一  日本水産学会大会講演要旨集  2011-  92  2011/03   [Not refereed] [Not invited]
  • UNNO Masaki, SASAKI Makoto, SAKAI Ryuichi, IKEDA-SAITO Masao  Nihon Kessho Gakkaishi  54-  (6)  338  -344  2012   [Not refereed] [Not invited]  
    Kainate receptors (KARs) are members of the ionotropic glutamate receptors (iGluR) that play variety of roles in the mammalian brain. Because KARs are comprised of five different isoform proteins, isoform selective compounds are indispensable tools in physiological researches. Dysiherbaine (DH) and neodysiherbaine A (NDH), natural toxins found from marine sponges, were shown to be potent and isoform-selective agonists for KARs. To understand structure-activity relationship of DH and NDH, numbers of analogues are synthesized, and their pharmacological activities have been evaluated in detail. Here, we determined the crystal structures of human KAR isoforms, GluK1 and GluK2, ligand-binding domain in complex with the DH analogues at high resolution. From these structures, we elucidated the relationships between the binding affinity and the molecular structure of the compounds. We also demonstrated differential recognition by some of the DH analogues of closely related isoforms GluK1 and GluK2. Further, we found that neither degree of the domain closure nor twist motion of domains directly correlated to agonist efficacy of the ligands.
  • R. Yagi, M. Tanaka, M. Tanaka, K. Sasaki, R. Kamata, Y. Nakanishi, Y. Kanai, R. Sakai  Oncogene  30-  1413  -1421  2011/03   [Not refereed] [Not invited]  
    During the analysis of phosphotyrosine-containing proteins in scirrhous gastric carcinoma cell lines, we observed an unusual expression of Arf-GAP with Rho-GAP domain, ankyrin repeat and PH domain 3 (ARAP3), a multimodular signaling protein that is a substrate of Src family kinases. Unlike other phosphotyrosine proteins, such as CUB domain-containing protein 1 (CDCP1) and Homo sapiens chromosome 9 open reading frame 10/oxidative stress-associated Src activator (C9orf10/Ossa), which are overexpressed and hyperphosphorylated in scirrhous gastric carcinoma cell lines, ARAP3 was underexpressed in cancerous human gastric tissues. In this study, we found that overexpression of ARAP3 in the scirrhous gastric carcinoma cell lines significantly reduced peritoneal dissemination. In vitro studies also showed that ARAP3 regulated cell attachment to the extracellular matrix, as well as invasive activities. These effects were suppressed by mutations in the Rho-GTPase-activating protein (GAP) domain or in the C-terminal two tyrosine residues that are phosphorylated by Src. Thus, the expression and phosphorylation state of ARAP3 may affect the invasiveness of cancer by modulating cell adhesion and motility. Our results suggest that ARAP3 is a unique Src substrate that suppresses peritoneal dissemination of scirrhous gastric carcinoma cells. © 2011 Macmillan Publishers Limited All rights reserved.
  • 佐々木翔太, 境倫宏, 酒井隆一, 及川雅人  日本化学会講演予稿集  91st-  (4)  1179  2011/03   [Not refereed] [Not invited]
  • Sakai Michihiro, Sasaki Shota, Ishikawa Yuichi, Sakai Ryuichi, Swanson Geoffrey T., Oikawa Masato  天然有機化合物討論会講演要旨集  53-  (53)  643  -648  2011/09   [Not refereed] [Not invited]  
    Micronesian marine sponge Lendenfeldia chondrodes contains structurally diverse neuroactive metabolites such as dysiherbaine, neodysiherbaine, dysibetaine, dysibetaine CPa and CPb, and cribronic acid, which have received significant attention from the synthetic community as structural motifs for developing novel neuroactive compounds. It is also of our considerable interest to use these metabolites as a probe for investigating functions of synaptic receptors. In the present study, we established a synthetic route to dysibetaine CPa (1) in racemic form, which is amenable to the analog synthesis, to study the biological function as well as the structure-activity relationships. Dysibetaine CPa (1) is a betaine consists of a quaternary ammonium group and two carboxyl groups, located on a novel 1,2,3-trisubstituted cyclopropane ring. From the synthetic point of view, differentiation of the functional groups on the cyclopropane ring is essential for the total synthesis but proved to be challenging during our study because of the instability of the synthetic intermediates. Upon considerable experimentation, we discovered that the cyclopropane ring was readily constructed by the reaction of N-(4-nitrophenyl)maleimide with sulfonium ylide 3. Reductive opening of the cyclopropane-fused imide 22 with NaBH_4 proceeded chemoselectively, giving rise to hydroxyamide 23. The amide was converted to ethyl ester over two steps, and then quaternary ammonium group was introduced by way of bromide 6'. Finally, acidic hydrolysis of two esters was effected by hydrochloric acid to achieve the total synthesis of dysibetaine CPa ((±ア)-1). Total yield was 4.5% for 12 steps. Furthermore, synthesis of five analogs was performed in the present study. Our route for the racemates, thus established here, will be also expanded to the asymmetric synthesis to determine the absolute stereochemistry of 1. Preliminary study indicated that all synthetic compounds did not induce noticeable behavioral change when 20 μg was administrated in mice intracerebroventricularly, as was observed with natural product.
  • 海野昌喜, 海野昌喜, 海野昌喜, 篠原正将, 高山昴一郎, 田中秀治, 酒井隆一, 佐々木誠, 齋藤正男  PFシンポジウム要旨集  28th-  97(7)  2011   [Not refereed] [Not invited]
  • Matsunaga Satoko, Sakai Ryuichi, Gill Martin B., Lash-Van Wyhe Leanne, Swanson Geoffrey T.  天然有機化合物討論会講演要旨集  53-  (53)  409  -413  2011/09   [Not refereed] [Not invited]  
    Aculeines (ACUs) are new peptide toxins isolated from the marine sponge A. aculeata collected at Iriomote, Okinawa. ACUs exhibited neurotoxicity through disrupting cell membrane and inducing robust influx of Ca^<2+> ions. ACUs are modified by long-chain polyamines (LCPAs) at the Nterminal amino acid. Amino acid sequence of the peptide portion of ACU-A was determined on the basis of Edman degradation, nucleotide sequence analysis, and peptide-mass mapping to be a 44-amino acid polypeptide. The peptide-mass mapping for ACU-B showed that it shares the same peptide portion with ACU-A. The nucleotide sequence analysis suggested that the Nterminal of ACU-A/B to be Trp, however; their structures were difficult to be elucidated because of a minute amount of peptides available and highly unusual modification by LCPA. In the present study, we isolated Nterminal fragments E and E' obtained from enzyme digest of ACU-A and B, respectively. We also found a novel LCPA derivative protoaculaine (1) that possibly represents the structures of the Nterminal portion of ACUs form the aqueous extract. Here we report the structure elucidation of those compounds.
  • Asakawa Tomohiro, Ohuchi Hitosi, Suzuki Hiroto, Isobe Youichiro, Higashia Takumi, Okazakia Yuko, Wakimoto Toshiyuki, Furuta Takumi, Shimamoto Keiko, Sakai Ryuichi, Hamashima Yoshitaka, Kan Toshiyuki  天然有機化合物討論会講演要旨集  53-  (53)  205  -210  2011/09   [Not refereed] [Not invited]  
    Recently, kainoids, such as kainic acid, have received significant attention due to their potent binding affinity for ionotropic glutamate receptors (iGluRs). iGluRs are involved in important neurophysiological processes, such as memory and learning. Although many synthetic investigations of kainoids have been reported to date, efficient synthetic methods are still strongly required. During the pioneering investigations on acromelic acid A, isolated by the Shirahama group, it was discovered that a synthetic derivative, methoxyphenyl kainic acid, possessed more potent activity than the natural compound. Inspired by this interesting structure-activity relationship, we launched an investigation into the development of efficient synthetic methods for achieving MFPA and phenylkainic acid. In our synthetic strategy, we envisioned that the three consecutive chiral centers were constructed based on the stereochemistry of the C4 position. We employed our asymmetric intermolecular C-H insertion reaction assisted by the chiral auxiliary using diazo ester and cyclohexadiene to afford the desired diene ester in high yield with good diastereoselectivity. After the conversion into the lactone by successive ozonolysis of cyclohexadiene, nitrogen was installed with Ns amide to give the corresponding hemiaminal. The reduction of the aminal and deprotection of the acetal induced the cyclization to construct a pyrrolidine ring with the correct stereochemistry. Introduction of two cyano groups were performed by diastereoselective Strecker-type reaction and Mitsunobu reaction. Finally, hydrolysis of the two cyano groups gave the synthetic kainoids. Furthermore, several investigations using the synthesized kainoids have elucidated that these compounds selectively bind to iGluRs and are equally effective for mice in vivo.
  • Hitoyasu Futami, Ryuichi Sakai  Cancer Letters  297-  220  -225  2010/11   [Not refereed] [Not invited]  
    Recently, gene amplification and gain-of-function mutations of ALK have been found in some neuroblastoma cell lines and clinical tumor samples. We have previously reported that knockdown of ALK by RNAi induced apoptosis in neuroblastoma cells with gene amplification of ALK. We report that all-trans retinoic acid (ATRA) downregulates ALK in neuroblastoma cell lines. Downregulation of ALK protein by ATRA was accompanied by apoptosis in neuroblastoma cells with gene amplification or gain-of-function mutation of ALK but not in neuroblastoma cells without these genetic alterations. These results suggest that ALK downregulation by ATRA might lead to apoptosis in neuroblastoma cells with activated ALK. © 2010 Elsevier Ireland Ltd.
  • Tatsuya Tazaki, Takaaki Sasaki, Kenta Uto, Norimasa Yamasaki, Satoshi Tashiro, Ryuichi Sakai, Minoru Tanaka, Hideaki Oda, Zen Ichiro Honda, Zen Ichiro Honda, Hiroaki Honda  Hepatology  52-  1089  -1099  2010/09   [Not refereed] [Not invited]  
    p130Cas, Crk-associated substrate (Cas), is an adaptor/scaffold protein that plays a central role in actin cytoskeletal reorganization. We previously showed that mice in which Cas was deleted (Cas -/- ) died in utero because of early cardiovascular maldevelopment. To further investigate the in vivo roles of Cas, we generated mice with a hypomorphic Cas allele lacking the exon 2-derived region (Cas Δex2/Δex2 ), which encodes Src homology domain 3 (SH3) of Cas. Cas Δex2/Δex2 mice again died as embryos, but they particularly showed progressive liver degeneration with hepatocyte apoptosis. Because Cas expression in the liver is preferentially detected in sinusoidal endothelial cells (SECs), the observed hepatocyte apoptosis was most likely ascribable to impaired function of SECs. To address this possibility, we stably introduced a Cas mutant lacking the SH3 domain (Cas ΔSH3) into an SEC line (NP31). Intriguingly, the introduction of Cas ΔSH3 induced a loss of fenestrae, the characteristic cell-penetrating pores in SECs that serve as a critical route for supplying oxygen and nutrients to hepatocytes. The disappearance of fenestrae in Cas ΔSH3-expressing cells was associated with an attenuation of actin stress fiber formation, a marked reduction in tyrosine phosphorylation of Cas, and defective binding of Cas to CrkII. Conclusion: Cas plays pivotal roles in liver development through the reorganization of the actin cytoskeleton and formation of fenestrae in SECs. Copyright © 2010 by the American Association for the Study of Liver Diseases.
  • 櫻田剛史, GILL Martin B., FRAUSTO Shanti, COPITS Bryan, 野口恵一, 島本啓子, SWANSON Geoffrey T., 酒井隆一  天然有機化合物討論会講演要旨集  52nd-  625-630  -630  2010/09   [Not refereed] [Not invited]
  • 及川雅人, 及川雅人, 生駒実, 佐々木誠, 酒井隆一, SWANSON Geoffrey  天然有機化合物討論会講演要旨集  52nd-  85-90  -90  2010/09   [Not refereed] [Not invited]
  • Hideki Yamaguchi, Hideki Yamaguchi, Hideki Yamaguchi, Shuhei Yoshida, Emi Muroi, Masahiro Kawamura, Zen Kouchi, Yoshikazu Nakamura, Ryuichi Sakai, Kiyoko Fukami  Cancer Science  101-  1632  -1638  2010/07   [Not refereed] [Not invited]  
    Invadopodia are ventral cell protrusions formed in invasive cancer cells. Because invadopodia have extracellular matrix (ECM) degradation activity, they are thought to function in cancer invasion. In this study, we examined the roles of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P 2 ] and PI(4,5)P 2 -producing enzymes in invadopodia formation in MDA-MB-231 human breast cancer cells. Immunofluorescence analysis showed that PI(4,5)P 2 accumulates at invadopodia on the ventral cell surface. Injection of an anti-PI(4,5)P 2 antibody inhibited invadopodia formation along with gelatin degradation activity. Sequestering of PI(4,5)P 2 by overexpression of the phospholipase C (PLC) δ1-pleckstrin homology (PH) domain, a specific probe for PI(4,5)P 2 , also blocked invadopodia formation, while a mutated PLCδ1-PH domain that lacks PI(4,5)P 2 -binding activity had no effect. Cellular PI(4,5)P 2 production is mainly mediated by type-I phosphatidylinositol 4-phosphate 5-kinase (PIP5KI) family proteins, which include PIP5KIα, Iβ, and Iγ. Real-time quantitative PCR analysis showed that PIP5KIα is a dominant isoform expressed in MDA-MB-231 cells. Knockdown of PIP5KIα by small-interfering RNA (siRNA) inhibited invadopodia formation and gelatin degradation. Immunofluorescence analysis revealed that endogenous PIP5KIα protein localizes at invadopodia, which is corroborated by the observation that exogenously expressed green fluorescent protein (GFP)-fused PIP5KIα protein also accumulates at gelatin degradation sites. These results indicate that localized production of PI(4,5)P 2 by PIP5KIα is required for invadopodia formation and ECM degradation by human breast cancer cells. © 2010 Japanese Cancer Association.
  • Yuri Miyazawa, Yuri Miyazawa, Takamasa Uekita, Nobuyoshi Hiraoka, Satoko Fujii, Tomoo Kosuge, Yae Kanai, Yoshihisa Nojima, Ryuichi Sakai  Cancer Research  70-  5136  -5146  2010/06   [Not refereed] [Not invited]  
    CUB domain-containing protein 1 (CDCP1) is a membrane protein that is highly expressed in several solid cancers. We reported previously that CDCP1 regulates anoikis resistance as well as cancer cell migration and invasion, although the underlying mechanisms have not been elucidated. In this study, we found that expression of CDCP1 in pancreatic cancer tissue was significantly correlated with overall survival and that CDCP1 expression in pancreatic cancer cell lines was relatively high among solid tumor cell lines. Reduction of CDCP1 expression in these cells suppressed extracellular matrix (ECM) degradation by inhibiting matrix metalloproteinase-9 secretion. Using the Y734F mutant of CDCP1, which lacks the tyrosine phosphorylation site, we showed that CDCP1 regulates cell migration, invasion, and ECM degradation in a tyrosine phosphorylation-dependent manner and that these CDCP1-associated characteristics were inhibited by blocking the association of CDCP1 and protein kinase Cδ (PKCδ). CDCP1 modulates the enzymatic activity of PKCδ through the tyrosine phosphorylation of PKCδ by recruiting PKCδ to Src family kinases. Cortactin, which was detected as a CDCP1-dependent binding partner of PKCδ, played a significant role in migration and invasion but not in ECM degradation of pancreatic cells. These results suggest that CDCP1 expression might play a crucial role in poor outcome of pancreatic cancer through promotion of invasion and metastasis and that molecules blocking the expression, phosphorylation, or the PKCδ-binding site of CDCP1 are potential therapeutic candidates. ©2010 AACR.
  • 喜田昭子, 神保充, 森本幸生, 酒井隆一, 神谷久男, 三木邦夫  日本蛋白質科学会年会プログラム・要旨集  10th-  112  2010/05   [Not refereed] [Not invited]
  • 浅川倫宏, 大内仁志, 鈴木寛人, 磯部洋一郎, 東匠, 岡崎優子, 脇本敏幸, 古田巧, 島本啓子, 酒井隆一, 濱島義隆, 菅敏幸  天然有機化合物討論会講演要旨集  53rd-  205-210  -210  2011/09   [Not refereed] [Not invited]
  • Mitsuru Jimbo, Hiroshi Yamashita, Hiroshi Yamashita, Kazuhiko Koike, Kazuhiko Koike, Ryuichi Sakai, Ryuichi Sakai, Hisao Kamiya  Fisheries Science  76-  355  -363  2010/03   [Not refereed] [Not invited]  
    We report herein the presence of a lectin in the scleractinian coral Ctenactis (Fungia) echinata. The lectin bound preferentially to lactose, melibiose, and d-galactose. The purified lectin CecL was composed of several isolectins, and it was found to have a molecular mass of 67.4 kDa via gel filtration. Glycopeptidase F-treated CecL showed a single band at 32.5 kDa. The mass/charge ratios of the reduced CecL peaks were equivalent to half those of the native peaks. These results suggest that CecL is composed of two glycosylated polypeptides linked by interchain disulfide bonds. In a biological activity test using a zooxanthellal culture (Dinoflagellate Symbiodinium) clonally isolated from Fungia cf. fungites, CecL transformed the flagellated motile form of Symbiodinium into the nonmotile coccoid form, a form equivalent to the symbiotic stage. The activity of CecL on Symbiodinium cells was concentration dependent, and 100 μg/ml CecL arrested Symbiodinium cells in the coccoid form for 5 days. CecL also suppressed the growth of Symbiodinium cells, unlike the octocoral lectin derived from Sinularia lochmodes, which arrests Symbiodinium cells in the coccoid form but does not affect the growth of the coccoid. This result provides further evidence that coral lectins play a role in symbiont engagement and maintenance in zooxanthellae-coral symbiosis. © The Japanese Society of Fisheries Science 2010.
  • M. B. Gill, S. Frausto, M. Ikoma, M. Sasaki, M. Oikawa, M. Oikawa, R. Sakai, G. T. Swanson  British Journal of Pharmacology  160-  1417  -1429  2010/01   [Not refereed] [Not invited]  
    Background and purpose: A new class of heterotricyclic glutamate analogues recently was generated by incorporating structural elements of two excitotoxic marine compounds, kainic acid and neodysiherbaine A. Rather than acting as convulsants, several of these 'IKM' compounds markedly depressed CNS activity in mice. Here, we characterize the pharmacological profile of the series with a focus on the most potent of these molecules, IKM-159. Experimental approach: The pharmacological activity and specificity of IKM compounds were characterized using whole-cell patch clamp recording from neurons and heterologous receptor expression systems, in combination with radioligand binding techniques. Key results: The majority of the IKM compounds tested reduced excitatory synaptic transmission in neuronal cultures, and IKM-159 inhibited synaptic currents from CA1 pyramidal neurons in hippocampal slices. IKM-159 inhibited glutamate-evoked whole-cell currents from recombinant GluA2- and GluA4-containing α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) receptors most potently, whereas kainate and NMDA receptor currents were not reduced by IKM-159. Antagonism of steady-state currents was agonist concentration dependent, suggesting that its mechanism of action was competitive, although it paradoxically did not displace [ 3 H]-AMPA from rec eptor binding sites. IKM-159 reduced spontaneous action potential firing in both cultured hippocampal neurons in control conditions and during hyperactive states in an in vitro model of status epilepticus. Conclusions and implications: IKM-159 is an AMPA receptor-selective antagonist. IKM-159 and related nitrogen heterocycles represent structurally novel AMPA receptor antagonists with accessible synthetic pathways and potentially unique pharmacology, which could be of use in exploring the role of specific populations of receptors in neurophysiological and neuropathological processes. © 2010 The British Pharmacological Society.
  • Masamitsu Tanaka, Masamitsu Tanaka, Reiko Kamata, Kazuyoshi Yanagihara, Ryuichi Sakai  Cancer Science  101-  87  -93  2010/01   [Not refereed] [Not invited]  
    Interaction of the Eph family of receptor protein tyrosine kinases and their ligands, ephrin family members, induces bidirectional signaling through cell-cell contacts. High expression of B-type ephrin is associated with high invasion potential of tumors, and we previously observed that signaling through the C-terminus of ephrin-B1 mediates the migration and invasion of cells, and is involved in the promotion of carcinomatous peritonitis in vivo. Here we show that the intracellular introduction of a synthetic peptide derived from ephrin-B1 C-terminus blocks ephrin-B1 mediated signaling in scirrhous gastric cancer cells. Treatment of cancer cells with a fusion peptide consisting of HIV-TAT and amino acids 331-346 of ephrin-B1 (PTD-EFNB1-C) suppressed the activation of RhoA, mediated by the association of ephrin-B1 with an adaptor protein Dishevelled, and also inhibited extracellular secretion of metalloproteinase. Moreover, injection of PTD-EFNB1-C peptide into the peritoneal cavity of nude mice suppressed carcinomatous peritonitis of intraperitoneally transplanted scirrhous gastric cancer cells. These results indicate the possible application of ephrin-B1 C-terminal peptide to develop novel protein therapy for scirrhous gastric carcinoma, especially in the stage of tumor progression, including peritoneal dissemination. © 2009 Japanese Cancer Association.
  • 喜田昭子, 神保充, 森本幸生, 酒井隆一, 神谷久男, 三木邦夫  PFシンポジウム要旨集  27th-  42  2010   [Not refereed] [Not invited]
  • 櫻田剛史, GILL Martin B., FRAUSTO Shanti, COPITS Bryan, 野口恵一, 島本啓子, SWANSON Geoffrey T., 酒井隆一  日本水産学会北海道支部大会講演要旨集  2010-  22  2010   [Not refereed] [Not invited]
  • 喜田昭子, 神保充, 森本幸生, 酒井隆一, 神谷久男, 三木邦夫  日本結晶学会年会講演要旨集  2010-  123  2010   [Not refereed] [Not invited]
  • Sakurada Tsuyoshi, Gill Martin B, Frausto Shanti, Copits Bryan, Noguchi Keiichi, Shimamoto Keiko, Swanson Geoffrey T., Sakai Ryuichi  天然有機化合物討論会講演要旨集  52-  (52)  625  -630  2010/09   [Not refereed] [Not invited]  
    Marine benthi organisms have yielded a variety of natural products with neuropharmacological applications. Here we describe the isolation and pharmacological characterization of four novel, neurologically active 8-oxoderivatives of purine, 1-4, isolated from Haplosclerida sponges collected in the Republic of Palau. The structure of 1 was determined based on spectral data and was confirmed by X-ray crystallography. The structures of 2-4 were determined similarly using spectral data by analogy of that of 1. Compound 1 induced convulsant behavior upon intracerebroventricular injection into mice, with a CD_<50> value of 2,4 nmol/mouse. Purines 2-4 were active in mouse bioassays at higher doses. The seizurogenic activity observed with 1 was correlated with inhibition of neruonal GABAergic transmission, with only a modest mpact of excitatory signaling, in electrophysiological recordings from hippoampal neurons in cultured and acute brain slice preparations. Despite having a purine template structure, the inhibitory activity of 1 was not prevented by a nonselective adenosine receptor antagonist. The natural product 1 therefore represents a novel substituted purine that elicits convulsions through its actions on inhibitory neurotransmission. The four 8-oxoisoguanine analogs comprise a new family of compounds closely related in structure to both important endogenous neurosignaling molecules and commonly used CNS stimulants.
  • 酒井隆一  化学と生物  47-  (10)  674  -675  2009/10   [Not refereed] [Not invited]
  • Oikawa Masato, Ikoma Minoru, Sasaki Makoto, Sakai Ryuichi, Swanson Geoffrey T.  天然有機化合物討論会講演要旨集  52-  (52)  85  -90  2010/09   [Not refereed] [Not invited]  
    Ionotropic glutamate receptors (iGluRs) are involved in higher brain functions such as memory and learning, nociception, and a number of brain disorders. Here, we report the synthesis of twelve artificial glutamate analogs whose core structure was inspired by two marine-derived excitatory amino acids, dysiherbaine and kainia acid. Four 7-oxznorbornenes, 2a-2d, were prepared in two steps, starting from and Ugi four component coupling reaction followed by spontaneous Diels-Alder reaction between 2-furfural, 3-iodoacrylic acid, 4-methoxybenzylamine, and benzyl isocyanide. An unprecedented domino metathesis reaction with less reactive vinyl acetate as a cross metathesis substrate was then performed with the Hoveyda-Grubbs second-generation catalyst, to successfully deliver four heterotricycles 3a-3d in good yiels. After functional group transformations followed by diversification at the C-ring, twelve artificial glutamate analogs 6a-6d, 7a-7d, 8a-8d were synthesized in total 7.2-25.8% yield for 13-15 steps. Mice in vivo assays indicated that all analogs are biologically active; namely, 6b, 7a, 7b, and 8b produce hyperactivity in injected i.c.v., whereas other analogs induce hypoactiity in the animals. In vitro electrophysiological assays showed that some hypoactive analogs inhibit spontaneous excitatory synaptic currents in hippocampal neurons and glutamate-evoked currents from recombinant AMPA receptors. With these pharmacological profiles, synthesis of other analogs werer further performed, and pyrrolidone dicarboxylic acid analog IKM-159 was discovered as a more potent, AMPA receptor-selective antagonist.
  • 松永智子, 酒井隆一, 神保充  日本水産学会大会講演要旨集  2009-  87  2009/09   [Not refereed] [Not invited]
  • 海野昌喜, 海野昌喜, 篠原正将, 高山昴一郎, 渡邉朋子, 田中秀治, 酒井隆一, 佐々木誠, 齋藤正男  生化学  ROMBUNNO.2T4A-6  2009/09   [Not refereed] [Not invited]
  • 松永智子, 酒井隆一, 神保充, GILL Martin B., SWANSON Geoffey T., 神谷久男  天然有機化合物討論会講演要旨集  51st-  599-604  -604  2009/09   [Not refereed] [Not invited]
  • Hitoyasu Futami, Ryuichi Sakai  Cancer Science  100-  1034  -1039  2009/06   [Not refereed] [Not invited]  
    The receptor tyrosine kinase RET is expressed in a number of neuroblastoma tissues and cell lines, but its role in neuroblastoma remains to be determined. In this study, we examined the roles of RET protein in neuroblastoma by the RNA interference technique using the NB-39-nu neuroblastoma cell line. NB-39-nu neuroblastoma cells show high expression and elevated tyrosine phosphorylation of RET, although short interfering RNA against RET (RET siRNA) did not significantly inhibit cell proliferation or suppression of basal levels of phosphorylation of extracellular regulated kinase (ERK)1/2 or protein kinase B (AKT). By the addition of glial cell line-derived neurotrophic factor (GDNF), both the expression and phosphorylation of RET and the phosphorylation of ERK1/2 and AKT were further increased, whereas cell proliferation was not stimulated under normal culture conditions. However, proliferation of cells cultured under non-adherent conditions was significantly increased by GDNF. The increased proliferation was suppressed by RET siRNA, which also caused inhibition of the phosphorylation of ERK1/2 and AKT. These results suggest that RET signaling plays an important role in GDNF-induced enhancement of non-adherent proliferation of NB-39-nu cells, which might contribute to the metastasis of neuroblastoma. (Cancer Sci 2009; 100: 1034-1039). © 2009 Japanese Cancer Association.
  • Jun Ichiro Ikeda, Tomofumi Oda, Tomofumi Oda, Masayoshi Inoue, Takamasa Uekita, Ryuichi Sakai, Meinoshin Okumura, Katsuyuki Aozasa, Eiichi Morii  Cancer Science  100-  429  -433  2009/04   [Not refereed] [Not invited]  
    CUB domain containing protein (CDCP1), a transmembrane protein with intracellular tyrosine residues which are phosphorylated upon activation, is supposed to be engaged in proliferative activities and resistance to apoptosis of cancer cells. Expression level of CDCP1 was examined in lung adenocarcinoma, and its clinical implications were evaluated. CDCP1 expression was immunohistochemically examined in lung adenocarcinoma from 200 patients. Staining intensity of cancer cells was categorized as low and high in cases with tumor cells showing no or weak and strong membrane staining, respectively. MIB-1 labeling index was also examined. There were 113 males and 87 females with median age of 63 years. Stage of disease was stage I in 144 cases (72.0%), II in 19 (9.5%), and III in 37 (18.5%). Sixty of 200 cases (30.0%) were categorized as CDCP1-high, and the remaining as CDCP1-low. Significant positive correlation was observed between CDCP1-high expression and relapse rate (P < 0.0001), poor prognosis (P < 0.0001), MIB-1 labeling index (P < 0.0001), and occurrence of lymph node metastasis (P = 0.0086). There was a statistically significant difference in disease-free survival (DFS) (P < 0.0001) and overall survival (OS) rates (P < 0.0001) between patients with CDCP1-high and CDCP1-low tumors. Univariate analysis showed that lymph node status, tumor stage, and CDCP1 expression were significant factors for both OS and DFS. Multivariate analysis revealed that only CDCP1 expression was an independent prognostic factor for both OS and DFS. CDCP1 expression level is a useful marker for prediction of patients with lung adenocarcinoma. © 2009 Japanese Cancer Association.
  • Kotaro Azuma, Tomohiko Urano, Tomohiko Urano, Kuniko Horie-Inoue, Shin Ichi Hayashi, Ryuichi Sakai, Yasuyoshi Ouchi, Satoshi Inoue, Satoshi Inoue, Satoshi Inoue, Satoshi Inoue  Cancer Research  69-  2935  -2940  2009/04   [Not refereed] [Not invited]  
    Estrogen receptor a (ERa) is a nuclear receptor that functions as a ligand-activated transcription factor. Besides its genomic action in nuclei, ERa could exert nongenomic actions at theplasma membrane. To investigate the mechanism underlyingthe nongenomic action of ERa in breast cancer cells, we generated a construct of membrane-targeted ERa (memER),an expression vector of ERa without the nuclear localizingsignal and including instead the membrane-targeting sequence of Src kinase. MemER was stably expressed in humanbreast cancer MCF-7 cells. Cell migration test and tumorigenicassay in nude mice revealed that the in vitro motility and the in vivo proliferation activity of MCF-7 cells expressing memER were significantly enhanced compared with those of vector-transfected cells. Interestingly, the acetylation level of tubulin in memER-overexpressing cells was lower than that in control cells. We found that histone deacetylase (HDAC) 6 translocated to the plasma membrane shortly after estrogen stimulation, and rapid tubulin deacetylation subsequently occurred. We also showed that memER associated with HDAC6 in a ligand-dependent manner. Although tamox- ifen is known for its antagonistic role in the ERa genomic action in MCF-7 cells, the agent showed an agonistic function in the memER-HDAC6 association and tubulin deacetylation. These findings suggest that ERa ligand dependently forms a complex with HDAC6 and tubulin at the plasma membrane. Estrogen-dependent tubulin deacetylation could provide new evidence for the nongenomic action of estrogen, which potentially contributes to the aggressiveness of ERa-positive breast cancer cells. ©2009 American Association for Cancer Research .
  • 中村友香, SWANSON Geffrey T., LASH Lianne L., 酒井隆一  日本水産学会大会講演要旨集  2009-  131  2009/03   [Not refereed] [Not invited]
  • 松永智子, 酒井隆一, 神保充, 神谷久男  日本水産学会大会講演要旨集  2009-  131  2009/03   [Not refereed] [Not invited]
  • WATANABE TOMOKO, TSUBONE KOICHI, OIKAWA MASATO, SASAKI MAKOTO, SAKAI RYUICHI, UNNO MASAKI, SAITO MASAO  日本化学会講演予稿集  89th-  (2)  1440  2009/03   [Not refereed] [Not invited]
  • OHIRA NAO, TSUBONE KOICHI, OIKAWA MASATO, SASAKI MAKOTO, SAKAI RYUICHI  日本化学会講演予稿集  89th-  (2)  1440  2009/03   [Not refereed] [Not invited]
  • 酒井隆一  生物の科学 遺伝  63-  (2)  60-64  -64  2009/03   [Not refereed] [Not invited]
  • I. Miyake, M. Ohira, A. Nakagawara, R. Sakai, R. Sakai  Oncogene  28-  662  -673  2009/02   [Not refereed] [Not invited]  
    The biological and clinical heterogeneity of neuroblastoma is closely associated with signaling pathways that control cellular characteristics such as proliferation, survival and differentiation. The Shc family of docking proteins is important in these pathways by mediating cellular signaling. In this study, we analysed the expression levels of ShcA and ShcC proteins in 46 neuroblastoma samples and showed that a significantly higher level of ShcC protein is observed in neuroblastomas with poor prognostic factors such as advanced stage and MYCN amplification (P < 0.005), whereas the expression level of ShcA showed no significant association with these factors. Using TNB1 cells that express a high level of ShcC protein, it was demonstrated that knockdown of ShcC by RNAi caused elevation in the phosphorylation of ShcA, which resulted in sustained extracellular signal-regulated kinase activation and neurite outgrowth. The neurites induced by ShcC knockdown expressed several markers of neuronal differentiation suggesting that the expression of ShcC potentially has a function in inhibiting the differentiation of neuroblastoma cells. In addition, marked suppression of in vivo tumorigenicity of TNB1 cells in nude mice was observed by stable knockdown of ShcC protein. These findings indicate that ShcC is a therapeutic target that might induce differentiation in the aggressive type of neuroblastomas. © 2009 Macmillan Publishers Limited All rights reserved.
  • Masamitsu Tanaka, Kazuki Sasaki, Reiko Kamata, Yukari Hoshino, Kazuyoshi Yanagihara, Ryuichi Sakai, Ryuichi Sakai  Molecular and Cellular Biology  29-  402  -413  2009/01   [Not refereed] [Not invited]  
    During the process of tumor progression and clinical treatments, tumor cells are exposed to oxidative stress. Tumor cells are frequently resistant to such stress by producing antiapoptotic signaling, including activation of Src family kinases (SFKs), although the molecular mechanism is not clear. In an attempt to identify the SFK-binding proteins selectively phosphorylated in gastric scirrhous carcinoma, we identified an uncharacterized protein, C9orf10. Here we report that C9orf10 (designated Ossa for oxidative stress-associated Src activator) is a novel RNA-binding protein that guards cancer cells from oxidative stress-induced apoptosis by activation of SFKs. Exposure to oxidative stress such as UV irradiation induces the association of Ossa/C9orf10 with regulatory domains of SFKs, which activates these kinases and causes marked tyrosine phosphorylation of C9orf10 in turn. Tyrosine-phosphorylated Ossa recruits p85 subunits of phosphatidylinositol 3-kinase (PI3-kinase) and behaves as a scaffolding protein for PI3-kinase and SFKs, which activates the Akt-mediated antiapoptotic pathway. On the other hand, the carboxyl terminus of Ossa has a distinct function that directly binds RNAs such as insulin-like growth factor II (IGF-II) mRNA and promotes the extracellular secretion of IGF-II. Our findings indicate that Ossa is a dual-functional protein and might be a novel therapeutic target which modulates the sensitivity of tumors to oxidative stress. Copyright © 2009, American Society for Microbiology. All Right Reserved.
  • 喜田昭子, 神保充, 森本幸生, 酒井隆一, 神谷久男, 三木邦夫  PFシンポジウム要旨集  26th-  96  2009   [Not refereed] [Not invited]
  • Matsunaga S., Sakai R., Jimbo M., Gill Martin B., Swanson Geoffrey T., Kamiya H.  天然有機化合物討論会講演要旨集  51-  (51)  599  -604  2009/09   [Not refereed] [Not invited]  
    In our quest for neurotoxic copounds in marine benthic organisms, we discovered novel functionalized peptide toxin aculeine A (Acu-A) from a sponge Axinyssa aculeata. Acu-A is a 45 amino acid-residue peptide with novel post translational modification with long chain polypropanamine attached to the N-terminus. Aculeines were proconvulsant in mice after contral administration. Acu-A was shown to induce calcium influx in cultures HEK293 cells and cultured rat hippocampal cells in an external Ca^<2+> dependent manner suggesting membrane disrupting function of the molecule. Partial amino acid sequence of Acu-A was determined by combination of Edman detradation and MADLDI-TOFMS analysis of the enzyme digests. The whole amino acid sequence for Acu A was deduced from nucleic acid sequence determined by 3' and 5'-RACE agreeing well with the above amino acid sequence where six cysteine residues were arranged like typical cystine knots such as conotoxin. These data suggested that Acu-A was a novel class of polyamine-modified cystine knots.
  • 田中秀治, 海野昌喜, 海野昌喜, 篠原正将, 高山昂一郎, 渡邉朋子, 酒井隆一, 佐々木誠, 齊藤正男  東北大学多元物質科学研究所研究発表会講演予稿集  9th-  142  2009   [Not refereed] [Not invited]
  • 海野昌喜, 海野昌喜, 篠原正将, 高山昴一郎, 渡邉朋子, 田中秀治, 酒井隆一, 佐々木誠, 齋藤正男  日本結晶学会年会講演要旨集  2009-  32  2009   [Not refereed] [Not invited]
  • Tetsuya Nakamoto, Tetsuya Nakamoto, Tetsuya Nakamoto, Tetsuya Nakamoto, Sachiko Seo, Ryuichi Sakai, Takayuki Kato, Haruo Kutsuna, Mineo Kurokawa, Masaki Noda, Masaki Noda, Nobuyuki Miyasaka, Nobuyuki Miyasaka, Seiichi Kitagawa  Journal of Cellular Biochemistry  105-  121  -128  2008/09   [Not refereed] [Not invited]  
    Crk-associated substrate lymphocyte type (Cas-L) protein, also known as human enhancer of filamentation 1 (Hef1) or neural precursor cell-expressed, developmentally down-regulated gene 9 (Nedd9), belongs to the Cas family of adapter proteins, which are involved in integrin signaling. Previous reports showed that Cas-L is expressed preferentially in lymphocytes and epithelial cells. Cas-L mediates signals from integrins, T-cell receptors, B-cells receptors, and transforming growth factor beta, leading to cell movement and cell division. Here, we report the expression of Cas-L in neutrophils. Cas-L was tyrosine-phosphorylated when human neutrophils were stimulated by fMLP, tumor necrosis factor-alpha (TNF), or lipopolysaccharide. The tyrosine phosphorylation of Cas-L in fMLP- or TNF-stimulated neutrophils was further enhanced by adhesion of the cells to their substrates. Cas-L was found to be localized at focal adhesions in stimulated neutrophils based on immunofluorescence microscopy. These findings suggest that Cas-L is one of the targets of inflammatory cytokines and is also modulated by cell adhesion process in neutrophils. © 2008 Wiley-Liss, Inc.
  • 海野昌喜, 篠原正将, 高山昴一郎, 酒井隆一, 佐々木誠, 齋藤正男  天然有機化合物討論会講演要旨集  50th-  173-178  -178  2008/09   [Not refereed] [Not invited]
  • Takamasa Uekita, Masamitsu Tanaka, Misato Takigahira, Yuri Miyazawa, Yukihiro Nakanishi, Yae Kanai, Kazuyoshi Yanagihara, Ryuichi Sakai, Ryuichi Sakai  American Journal of Pathology  172-  1729  -1739  2008/06   [Not refereed] [Not invited]  
    CUB-domain-containing protein 1 (CDCP1) is a type-I transmembrane protein that is highly expressed in colon, breast, and lung cancers. We recently revealed that CDCP1 is associated with and phosphorylated by Src family kinases and is involved in the regulation of anchorage independence of certain lung cancer cell lines. In this study, we examined whether CDCP1 is involved in the regulation of tumor progression of scirrhous gastric cancer, which is a diffusely infiltrative carcinoma with high invasion potential. Expression and phosphorylation levels of CDCP1 correlated with the invasive potential of scirrhous gastric cancers. Reduction of CDCP1 expression by siRNA suppressed migration, invasion, and anchorage independence without affecting the proliferation of highly invasive scirrhous gastric cancer cells. However, CDCP1 overexpression promoted gastric cancer cell migration with low potential of invasion. Loss of CDCP1 suppressed invasion and dissemination of cancer cells that were orthotopically implanted in the gastric wall of nude mice. Expression and phosphorylation of CDCP1 were also detected in cancer cells of surgically resected tissues of human scirrhous gastric cancer by immunohistochemical analysis. Our results suggest that CDCP1 promotes invasion and peritoneal dissemination of cancer cells through the regulation of cell migration and anchorage independence. Therefore, it is both a potential prognostic and therapeutic target in certain types of gastrointestinal cancers, and suppression of its phosphorylation might be a useful strategy for modulating cancer metastasis. Copyright © American Society for Investigative Pathology.
  • Lin Jia, Takamasa Uekita, Ryuichi Sakai, Ryuichi Sakai  Molecular Cancer Research  6-  654  -662  2008/04   [Not refereed] [Not invited]  
    Cortactin is frequently overexpressed in cancer cells, and changes of the levels of its tyrosine phosphorylation have been observed in several cancer cells. However, how the expression level and phosphorylation state of cortactin would influence the ultimate cellular function ofcancer cells is unknown. In this study, we analyzed the role of cortactin in gastric and breast cancer cell lines using RNA interference technique and found that knockdown of cortactin inhibited cell migration in a subset ofgastric cancer cells with a lower level of its tyrosine phosphorylation, whereas it greatly enhanced cell migration and increased tyrosine phosphorylation of p130Cas in other subsets of cells with hyperphosphorylated cortactin. Consistent results were obtained when hyperphosphorylation of cortactin was induced in MCF7 breast cancer cells by expressing Fyn tyrosine kinase. Additionally, immunostaining analysis showed that knockdown of hyperphosphorylated cortactin resulted in the recruitment of p130Cas to focal adhesions. These results suggest that cortactin hyperphosphorylation suppresses cell migration possibly through the inhibition of membrane localization and tyrosine phosphorylation of p130Cas. Copyright © 2008 American Association for Cancer Research.
  • 町田平, 神保充, 酒井隆一, 神谷久男  日本水産学会大会講演要旨集  2008-  65  2008/03   [Not refereed] [Not invited]
  • 局興一, 青木邦衛, 及川雅人, 酒井隆一, 島本啓子, 佐々木誠  日本化学会講演予稿集  88th-  (2)  1041  2008/03   [Not refereed] [Not invited]
  • Tatsuya Tazaki, Tatsuya Tazaki, Kazuko Miyazaki, Eiso Hiyama, Tetsuya Nakamoto, Ryuichi Sakai, Norimasa Yamasaki, Zen ichiro Honda, Masaki Noda, Nobuyuki Miyasaka, Taijiro Sueda, Hiroaki Honda  Genes to Cells  13-  145  -157  2008/02   [Not refereed] [Not invited]  
    p130Cas (Cas, Crk-associated s ubstrate) is an adaptor molecule composed of a Src homology 3 (SH3) domain, a substrate domain (SD) and a Src binding domain (SBD). The SH3 domain of Cas associates with focal adhesion kinase (FAK), but its role in cellular function has not fully been understood. To address this issue, we established and analyzed primary fibroblasts derived from mice expressing a truncated Cas lacking exon 2, which encodes the SH3 domain (Cas Δexon 2). In comparison to wild-type cells, Cas exon 2 Δ/Δ cells showed reduced motility, which could be due to impaired tyrosine-phosphorylation of FAK and Cas, reduced FAK/Cas/Src/CrkII binding, and also impaired localization of Cas Δexon 2 to focal adhesions on fibronectin. In addition, to analyze downstream signaling pathways regulated by Cas exon 2, we performed microarray analyses. Interestingly, we found that a deficiency of Cas exon 2 up-regulated expression of CXC Chemokine Receptor-4 and CC Chemokine Receptor-5, which may be regulated by IκBα phosphorylation. These results indicate that the SH3-encoding exon of Cas participates in cell motility, tyrosine-phosphorylation of FAK and Cas, FAK/Cas/Src/CrkII complex formation, recruitment of Cas to focal adhesions and regulation of cell motility-associated gene expression in primary fibroblasts. Journal compilation © 2008 by the Molecular Biology Society of Japan/Blackwell Publishing Ltd.
  • 喜田昭子, 神保充, 森本幸生, 酒井隆一, 神谷久男, 三木邦夫  生化学  4P-0107  2008   [Not refereed] [Not invited]
  • 生駒実, 及川雅人, 佐々木誠, 酒井隆一  有機合成シンポジウム講演要旨集  93rd-  65-68  -68  2008   [Not refereed] [Not invited]
  • Takamasa Uekita, Lin Jia, Mako Narisawa-Saito, Jun Yokota, Tohru Kiyono, Ryuichi Sakai, Ryuichi Sakai  Molecular and Cellular Biology  27-  7649  -7660  2007/11   [Not refereed] [Not invited]  
    Malignant tumor cells frequently achieve resistance to anoikis, a form of apoptosis induced by detachment from the basement membrane, which results in the anchorage-independent growth of these cells. Although the involvement of Src family kinases (SFKs) in this alteration has been reported, little is known about the signaling pathways involved in the regulation of anoikis under the control of SFKs. In this study, we identified a membrane protein, CUB-domain-containing protein 1 (CDCP1), as an SFK-binding phosphoprotein associated with the anchorage independence of human lung adenocarcinoma. Using RNA interference suppression and overexpression of CDCP1 mutants in lung cancer cells, we found that tyrosine-phosphorylated CDCP1 is required to overcome anoikis in lung cancer cells. An apoptosis-related molecule, protein kinase Cδ, was found to be phosphorylated by the CDCP1-SFK complex and was essential for anoikis resistance downstream of CDCP1. Loss of CDCP1 also inhibited the metastatic potential of the A549 cells in vivo. Our findings indicate that CDCP1 is a novel target for treating cancer-specific disorders, such as metastasis, by regulating anoikis in lung adenocarcinoma. Copyright © 2007, American Society for Microbiology. All Rights Reserved.
  • 神保充, 本橋詳子, 酒井隆一, 神谷久男  日本動物学会大会要旨集  78th-  41  2007/08   [Not refereed] [Not invited]
  • Unno Masaki, Shinohara Masanobu, Takayama Koichiro, Sakai Ryuichi, Sasaki Makoto, Ikeda-Saito Masao  天然有機化合物討論会講演要旨集  0-  (50)  173  -178  2008/09   [Not refereed] [Not invited]  
    Dysiherbaine (DH) and its congener neodysiherbaine A (NDH) are naturally occurring excitatory amino acids with high-affinity and subunit-selectivity for kainate type ionotropic glutamate receptors, especially GluR5 and GluR6 subunits. To elucidate why DH and NDH bind selectively to GluR5, we have determined the crystal structures of human GluR5 ligand-binding core in complexes with DH and NDH, in addition to the glutamate-complex. DH and NDH form unique hydrogen-bonding and hydrophobic interactions with the amino acid residues in the binding-cleft by excluding the water molecules, which med...

Research Grants & Projects

  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(C))
    Date (from‐to) : 2007 -2009 
    Author : Yasushi SHIGERI
     
    独立行政法人産業技術総合研究所Alanine-serine-cysteine transporters (ASCT1, 2) are neutral amino acids transporters. Their representative substrates are alanine, serine and cysteine. Since th ere is no specific inhibitors or substrates for ASCT1 and ASCT2, their physiological functions are quite mystery. To develop their specific compounds to modulate their functions, high-throughput screening is essential. Therefore, we made two approaches as follows. First, we looked for host cells with lower level of endogenous ASCT1 or ASCT2. We checked CHO cells, HEK293 cells, 3T3 cells and other cells. But all of the cells that we ...
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(B))
    Date (from‐to) : 2005 -2007 
    Author : Ryuichi SAKAI
     
    北里大学In the present study, we identified new polyamines from a Okinawan sponge Axinissa aculeate that modulate ligand binding to NMDA type glutamate receptors. These polyamines may also function as a factor involved in silica biomineralization in the sponge. From the same extract, we identified new peptides containing polyamine in the substructure and named aculeines. This novel highly modified peptide showed strong convulsant actions in mice. We also isolated Cribropurine, a new purine from a Micronesian sponge Chribrocharina olemda. Cribroprine elicited a seizure-like spontaneous current in ra...
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(B))
    Date (from‐to) : 2003 -2005 
    Author : Hisao KAMIYA
     
    北里大学The D-galactose-binding lectin, Sll-2, in the octocoral was effectively purified by affinithy chromatography on D-galactosamine-HiTrap column using Tris-HCl buffer containing 0.5% L-ascorbic acid and 0.1% kojic acid to avoid melanization and insolubilization of SLL-2 during purification. The purified SLL-2 gave many spot in 2D-PAGE with different pI values rangin from 3 to 5. However, after the N-glycopeptidase F treatment, the molecular weight of subunit (16.5kDa) reduced to 9.5kDa with three different pIs. These results suggested that SLL-2 is a mixture of isolectins composed of three gly...
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(C))
    Date (from‐to) : 2003 -2004 
    Author : Ryuichi SAKAI
     
    北里大学We have investigated the cellular localization of the marine sponge-derived excitatory amino acid dysiherbaine (DH), and found that DH-like immunoreactivity was densely located in the large (10 μm) globular cells. On the basis of 18S rDNA sequence analysis it was shown that this cell belongs to the sponge itself, however, results from fluorescent microscopy and immunohistochemistry using anti-phycobilin antibody indicated that this cell contains phycobilin, a photosynthetic pigment of cyanobacteria. Although number of histological observations of D.herbacea are available in literature, cell...
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(B))
    Date (from‐to) : 2000 -2003 
    Author : Shigeru SATO
     
    北里大学Although many sophisticated analyzing methods for paralytic shellfish toxins (PSP toxins) have been developed, mouse bioassay is still applied as official method for monitoring of bivalve toxicity in various countries including Japan. Mouse bioassay is a simple and reliable method, but many problems about animal experiments have been pointed out for this method. Currently a simple and rapid method which could be replaceable with mouse bioassay is needed. ELISA far PSP toxins is one of the first candidates. In order to make specific antibody against toxins required for ELISA, hapten antigen ...
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(B))
    Date (from‐to) : 2000 -2002 
    Author : Hisao KAMIYA
     
    北里大学The cDNA cloning of SLL-2, a D-galactose-binding lectin of the octocoral Sinularia lochmodes, has revealed that SLL-2 had a sequence homology to those of "discoidin" group lectins. It is observed that the difference of 2 kD in the molecular weight of SLL-2 was present between that calculated from the deduced amino acid sequence of SLL-2 (10, 751) and that observed in SDS-PAGE(15, 000) and TOF-MS (13, 194). No neutral sugar was observed. On the other hand, the spectroscopic analysis and also a treatment with tyrosinase suggested the presence of dopa in a lectin molecule. SLL-2 seems to have ...
  • Isolation and structure determination of Bioactive Marine natural products.

Educational Activities

Teaching Experience

  • Environment and People
    開講年度 : 2017
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 生物資源,資源利用,機能性,マリンバイオマス,環境保全,マリンバイオテクノロジー,有効利用,高度利用
  • Natural Product Chemistry
    開講年度 : 2017
    課程区分 : 学士課程
    開講学部 : 水産学部
    キーワード : 生理活性物質 2次代謝物 海洋天然物 天然毒 生合成 ポリケチド イソプレノイド アルカロイド ペプチド
  • Environment and People
    開講年度 : 2017
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 海、河川、生命、細胞、遺伝子、魚、海藻、微生物、代謝、進化


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