Springer Science and Business Media LLC Acta Medica Okayama 2045-2322 16 1 2026 Pseudohypoxia induced by iron chelators preserves working memory performance in aged mice 11550 EN Toshiaki Ohara Department of Pathology and Experimental Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Yoshiaki Iwasaki Health Service Section, Environment Health & Safety Intelligence Department, Okayama University Tomonari Kasai Department of Applied Energy, Graduate School of Engineering, Nagoya University Toru Yamashita Department of Neurology, Graduate School of Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Shiho Komaki Department of Pathology and Experimental Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Yusuke Hamada Department of Pathology and Experimental Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Masayoshi Fujisawa Department of Pathology and Experimental Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Akihiro Matsukawa Department of Pathology and Experimental Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Pseudohypoxia refers to a physiological condition wherein hypoxia-inducible factor (HIF) is pharmacologically upregulated under normoxia, thereby modulating immune responses. We hypothesized that pseudohypoxia, induced by iron chelators, may similarly potentiate systemic immune responses in aged mice, concurrently triggering neuro-regenerative signaling pathways and enhancing cognitive performance. In this study, aged mice (43–48 weeks old) were orally administered two iron chelators, Super Polyphenol 10 (SP10) or Roxadustat, to induce a pseudohypoxia. An 8-week oral regimen of SP10 and Roxadustat significantly preserved working memory, as assessed by the Y-maze test (YMT). White blood cell counts and hippocampal volume, as assessed by magnetic resonance imaging (MRI), were elevated in the treatment groups relative to controls. Pseudohypoxia induced by SP10 tended to enhance neuro-regenerative signaling, specifically involving the Tau and JNK pathways, and potentially modulated Doublecortin (DCX) expression, although statistical significance was limited by sample size. Importantly, inflammatory markers, such as ionized calcium-binding adapter molecule 1 (Iba1) and glial fibrillary acidic protein (GFAP), were not elevated by treatment. Collectively, these findings suggest that pseudohypoxia induced by iron chelators preserves working memory performance accompanied by leukocytosis, without concomitant neuroinflammation. No potential conflict of interest relevant to this article was reported.

Elsevier Acta Medica Okayama 0168-3659 330 2020 Self-assembling A6K peptide nanotubes as a mercaptoundecahydrododecaborate (BSH) delivery system for boron neutron capture t (BNCT) 788 196 EN Hiroyuki Michiue Neutron Therapy Research Center, Okayama University Mizuki Kitamatsu Department of Applied Chemistry, Kindai University Asami Fukunaga Department of Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Nobushige Tsuboi Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Atsushi Fujimura Department of Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Hiroaki Matsushita Department of Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kazuyo Igawa Neutron Therapy Research Center, Okayama University Tomonari Kasai Neutron Therapy Research Center, Okayama University Natsuko Kondo Institute for Integrated Radiation and Nuclear Science, Kyoto University Hideki Matsui Neutron Therapy Research Center, Okayama University Shuichi Furuya Neutron Therapy Research Center, Okayama University Boron neutron capture therapy (BNCT) is a tumor selective therapy, the effectiveness of which depends on sufficient 10B delivery to and accumulation in tumors. In this study, we used self-assembling A6K peptide nanotubes as boron carriers and prepared new boron agents by simple mixing of A6K and BSH. BSH has been used to treat malignant glioma patients in clinical trials and its drug safety and availability have been confirmed; however, its contribution to BNCT efficacy is low. A6K nanotube delivery improved two major limitations of BSH, including absence of intracellular transduction and non-specific drug delivery to tumor tissue. Varying the A6K peptide and BSH mixture ratio produced materials with different morphologies—determined by electron microscopy—and intracellular transduction efficiencies. We investigated the A6K/BSH 1:10 mixture ratio and found high intracellular boron uptake with no toxicity. Microscopy observation showed intracellular localization of A6K/BSH in the perinuclear region and endosome in human glioma cells. The intracellular boron concentration using A6K/BSH was almost 10 times higher than that of BSH. The systematic administration of A6K/BSH via mouse tail vein showed tumor specific accumulation in a mouse brain tumor model with immunohistochemistry and pharmacokinetic study. Neutron irradiation of glioma cells treated with A6K/BSH showed the inhibition of cell proliferation in a colony formation assay. Boron delivery using A6K peptide provides a unique and simple strategy for next generation BNCT drugs. No potential conflict of interest relevant to this article was reported.

Public Library Science Acta Medica Okayama 1932-6203 9 9 2014 Efficient Drug Delivery of Paclitaxel Glycoside: A Novel Solubility Gradient Encapsulation into Liposomes Coupled with Immunoliposomes Preparation e107976 EN Tsukasa Shigehiro Tomonari Kasai Masaharu Murakami Sreeja C. Sekhar Yuki Tominaga Masashi Okada Takayuki Kudoh Akifumi Mizutani Hiroshi Murakami David S. Salomon Katsuhiko Mikuni Tadakatsu Mandai Hiroki Hamada Masaharu Seno Although the encapsulation of paclitaxel into liposomes has been extensively studied, its significant hydrophobic and uncharged character has generated substantial difficulties concerning its efficient encapsulation into the inner water core of liposomes. We found that a more hydrophilic paclitaxel molecule, 7-glucosyloxyacetylpaclitaxel, retained tubulin polymerization stabilization activity. The hydrophilic nature of 7-glucosyloxyacetylpaclitaxel allowed its efficient encapsulation into the inner water core of liposomes, which was successfully accomplished using a remote loading method with a solubility gradient between 40% ethylene glycol and Cremophor EL/ethanol in PBS. Trastuzumab was then conjugated onto the surface of liposomes as immunoliposomes to selectively target human epidermal growth factor receptor-2 (HER2)-overexpressing cancer cells. In vitro cytotoxicity assays revealed that the immunoliposomes enhanced the toxicity of 7-glucosyloxyacetylpaclitaxel in HER2-overexpressing cancer cells and showed more rapid suppression of cell growth. The immunoliposomes strongly inhibited the tumor growth of HT-29 cells xenografted in nude mice. Notably, mice survived when treated with the immunoliposomes formulation, even when administered at a lethal dose of 7-glucosyloxyacetylpaclitaxel in vivo. This data successfully demonstrates immunoliposomes as a promising candidate for the efficient delivery of paclitaxel glycoside. No potential conflict of interest relevant to this article was reported.

PUBLIC LIBRARY SCIENCE Acta Medica Okayama 1932-6203 7 4 2012 A Model of Cancer Stem Cells Derived from Mouse Induced Pluripotent Stem Cells e33544 EN Ling Chen Tomonari Kasai Yueguang Li Yuh Sugii Guoliang Jin Masashi Okada Arun Vaidyanath Akifumi Mizutani Ayano Satoh Takayuki Kudoh Mary J. C. Hendrix David S Salomon Li Fu Masaharu Seno Cancer stem cells (CSCs) are capable of continuous proliferation and self-renewal and are proposed to play significant roles in oncogenesis, tumor growth, metastasis and cancer recurrence. CSCs are considered derived from normal stem cells affected by the tumor microenvironment although the mechanism of development is not clear yet. In 2007, Yamanaka's group succeeded in generating Nanog mouse induced pluripotent stem (miPS) cells, in which green fluorescent protein (GFP) has been inserted into the 5'-untranslated region of the Nanog gene. Usually, iPS cells, just like embryonic stem cells, are considered to be induced into progenitor cells, which differentiate into various normal phenotypes depending on the normal niche. We hypothesized that CSCs could be derived from Nanog miPS cells in the conditioned culture medium of cancer cell lines, which is a mimic of carcinoma microenvironment. As a result, the Nanog miPS cells treated with the conditioned medium of mouse Lewis lung carcinoma acquired characteristics of CSCs, in that they formed spheroids expressing GFP in suspension culture, and had a high tumorigenicity in Balb/c nude mice exhibiting angiogenesis in vivo. In addition, these iPS-derived CSCs had a capacity of self-renewal and expressed the marker genes, Nanog, Rex1, Eras, Esg1 and Cripto, associated with stem cell properties and an undifferentiated state. Thus we concluded that a model of CSCs was originally developed from miPS cells and proposed the conditioned culture medium of cancer cell lines might perform as niche for producing CSCs. The model of CSCs and the procedure of their establishment will help study the genetic alterations and the secreted factors in the tumor microenvironment which convert miPS cells to CSCs. Furthermore, the identification of potentially bona fide markers of CSCs, which will help the development of novel anti-cancer therapies, might be possible though the CSC model. No potential conflict of interest relevant to this article was reported.