Publications by authors named "Ii H"

Article Synopsis
  • Glioblastoma stem cells (GSCs) contribute to the aggressive nature of glioblastoma by making the tumor resistant to therapies, and high levels of γ-Glutamylcyclotransferase (GGCT) are linked to this resistance.
  • Inhibition of GGCT reduces GSC proliferation, and its expression is regulated by the protein c-Jun, which is influenced by the NRas protein.
  • GGCT knockdown not only hampers GSC growth but also disrupts the Delta-Notch signaling pathway by lowering Notch1 levels, suggesting GGCT is a promising target for new glioblastoma treatments.
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Certain cancer cells depend on oxidative phosphorylation for survival; thus, inhibiting this process may be a promising treatment strategy. This study explored the structure-activity relationships of the mitochondrial inhibitor -ethylene glycol-comprising alkyl thiophene-3-carboxamide . We synthesized and evaluated 13 analogs (-) with different ethylene glycol units, heterocycles and connecting groups for their growth-inhibitory effects on A549 non-small cell lung cancer cells.

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Background/aim: Glioblastoma is the most frequent type of adult-onset malignant brain tumor and has a very poor prognosis. Glioblastoma stem cells have been shown to be one of the mechanisms by which glioblastoma acquires therapy resistance. Therefore, there is a need to establish novel therapeutic strategies useful for inhibiting this cell population.

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Osteosarcoma (OS) in humans is characterized by alterations in the TP53 gene. In mice, loss of p53 triggers OS development, for which c-Myc (Myc) oncogenicity is indispensable. However, little is known about which genes are targeted by Myc to promote tumorigenesis.

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γ-Glutamylcyclotransferase (GGCT) is highly expressed in multiple types of cancer tissues and its knockdown suppresses the growth of cancer cells in vitro and in vivo. Although GGCT is a promising target for cancer therapy, the mechanisms underlying the antitumor effects remain unclear. The knockdown of GGCT inhibited the MEK-ERK pathway, and activated the tumor suppressor retinoblastoma gene (RB) at the protein level in cancer cell lines.

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While γ-glutamylcyclotransferase (GGCT) has been implicated in cancer-cell proliferation, the role of GGCT enzymatic activity in the regulation of cancer-cell growth remains unclear. Toward further understanding of GGCT , here we report a novel cell-permeable chemiluminogenic probe "MAM-LISA-103" that detects intracellular GGCT activity and apply it to imaging. We first developed a chemiluminogenic probe LISA-103, which simply and sensitively detects the enzymatic activity of recombinant GGCT through chemiluminescence.

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Glioblastoma is a refractory malignant tumor that requires novel therapeutic strategies for effective treatment. We have previously reported that JCI-20679 (), an analog of annonaceous acetogenins, shows potent antitumor activity against glioblastomas. However, the synthesis of requires 23 steps, including 16 steps for the preparation of a tetrahydrofuran (THF) moiety.

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Background/aim: Glioblastoma is the most common and aggressive malignant brain tumor in adults, and glioblastoma stem cells (GSCs) contribute to treatment resistance and recurrence. Inhibition of Stat5b in GSCs suppresses cell proliferation and induces apoptosis. Herein, we investigated the mechanisms of growth inhibition by Stat5b knockdown (KD) in GSCs.

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Background/aim: γ-Glutamylcyclotransferase (GGCT) is up-regulated in a broad range of cancers, including breast cancer, and GGCT inhibition has been shown to be a promising strategy for therapy. Herein, we evaluated the efficacy and mechanism of action of pro-GA, a GGCT enzymatic inhibitor, in MCF7 breast cancer cells.

Materials And Methods: Proliferation was evaluated by WST-8 and trypan blue dye exclusion assays.

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Article Synopsis
  • Fluorizoline is a cytotoxic compound that targets specific proteins (PHB1/2) to inhibit cancer growth by affecting key pathways, including enhancing the inhibitor p21 to kill cancer cells.
  • The study identifies new fluoroziline analogues with improved effectiveness against cancer cells, specifically noting that some have better anti-C-RAF and anti-MEK activities than fluorizoline itself.
  • Additionally, a different analogue was found that exhibits effects opposite to fluorizoline, which could help researchers study how PHB signaling functions in cancer and other diseases.
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The prognosis of glioblastoma, which is the most frequent type of adult‑onset malignant brain tumor, is extremely poor. Therefore, novel therapeutic strategies are needed. Previous studies report that JCI‑20679, which is synthesized based on the structure of naturally occurring acetogenin, inhibits mitochondrial complex I and suppresses the growth of various types of cancer cells.

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Glioblastoma (GBM) is the most common and malignant type of brain cancer in adults with poor prognosis. GBM stem cells (GSCs) reside within niches in GBM tissues and contribute to recurrence and therapy resistance. Previous studies have shown that expression of leucine-rich repeat-containing G-protein coupled receptor 5 (Lgr5), a Wnt pathway-related stem cell marker, correlates with a poor prognosis in GBM, and its knockdown in GSCs induces apoptosis accompanied with downregulation of signal transducer and activator of transcription 5b (Stat5b).

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Background/aim: γ-Glutamyl cyclotransferase (GGCT) is up-regulated in various cancer types, including lung cancer. In this study, we evaluated efficacy of gapmer-type antisense oligonucleotides (ASOs) targeting GGCT in an A549 lung cancer xenograft mouse model and studied their mechanisms of action.

Materials And Methods: GGCT was inhibited using GGCT-ASOs and cell proliferation was evaluated by dye exclusion test.

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Glioblastoma, a type of brain cancer, is one of the most aggressive and lethal types of malignancy. The present study shows that JCI-20679, an originally synthesized mitochondrial complex I inhibitor, enhances the anti-proliferative effects of suboptimal concentrations of the clinically used chemotherapeutic drug temozolomide in glioblastoma cells. Analysis of the effects of temozolomide combined with JCI-20679 using isobologram and combination index methods demonstrated that the combination had synergistic effects in murine and human glioblastoma cells.

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Article Synopsis
  • Prohibitin-2 (PHB2) is a protein that has multiple functions, including interaction with GGCT in the cytoplasm and gene repression in the nucleus.
  • The drug fluorizoline binds to PHB1/2, showing potential to inhibit the growth of cancer cells by inducing p21 expression, particularly in MCF7 breast cancer cells.
  • The study suggests that fluorizoline's anticancer effects involve blocking cell proliferation through p21 induction and disrupting the interaction between PHB2 and GGCT, which affects PHB2 localization in the nucleus.
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γ-Glutamylcyclotransferase (GGCT) is involved in glutathione homeostasis, in which it catalyzes the reaction that generates 5-oxoproline and free amino acids from γ-glutamyl peptides. Increasing evidence shows that GGCT has oncogenic functions and is overexpressed in various cancer tissues, and that inhibition of GGCT activity exerts anticancer effects in vitro and in vivo. Here, we demonstrate that U83836E ((2R)-2-[[4-(2,6-dipyrrolidin-1-ylpyrimidin-4-yl)piperazin-1-yl]methyl]-3,4-dihydro-2,5,7,8,-tetramethyl-2H-1-benzopyran-6-ol, dihydrochloride), a lazaroid that inhibits lipid peroxidation, inhibits GGCT enzymatic activity.

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The prognosis of glioblastoma remains poor despite intensive research efforts. Glioblastoma stem cells (GSCs) contribute to tumorigenesis, invasive capacity, and therapy resistance. Leucine-rich repeat-containing G-protein coupled receptor 5 (Lgr5), a stem cell marker, is involved in the maintenance of GSCs, although the properties of Lgr5-positive GSCs remain unclear.

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Metabolic reprogramming leading to aerobic glycolysis, termed the "Warburg effect," is a critical property of cancer cells. However, the precise mechanisms underlying this phenomenon are not fully understood. A growing body of evidence indicates that γ-glutamylcyclotransferase (GGCT), an enzyme involved in glutathione homeostasis that is highly expressed in many types of cancer, represents a promising therapeutic target.

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This study evaluated the assumption that back-filled excavated areas of old mine workings can be modeled as porous media, where groundwater flow is governed by Darcy's law. The Yatani mine, located in Yamagata Prefecture, Japan, was selected for this study because several mining methods were used during its operation and detailed drawings of the excavated areas of the mine are available. The model was calibrated using combinations of hydraulic conductivities (k), with the best-matched case being selected by comparing calculated and measured AMD fluxes.

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How did chemicals first become organized into systems capable of self-propagation and adaptive evolution? One possibility is that the first evolvers were chemical ecosystems localized on mineral surfaces and composed of sets of molecular species that could catalyze each other's formation. We used a bottom-up experimental framework, chemical ecosystem selection (CES), to evaluate this perspective and search for surface-associated and mutually catalytic chemical systems based on the changes in chemistry that they are expected to induce. Here, we report the results of preliminary CES experiments conducted using a synthetic "prebiotic soup" and pyrite grains, which yielded dynamical patterns that are suggestive of the emergence of mutual catalysis.

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Article Synopsis
  • The study focuses on γ-Glutamylcyclotransferase (GGCT), a protein found in high levels in various cancers, and its potential as a target for therapy.
  • Researchers explored if blocking GGCT would enhance the effectiveness of docetaxel, a drug used in prostate cancer treatment.
  • Results showed that GGCT inhibition reduced cancer cell growth and, when combined with docetaxel, produced stronger anti-cancer effects than either treatment alone.
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Inhibition of gamma-glutamylcyclotransferase (GGCT), which is highly expressed in various cancer tissues, exerts anticancer effects both in vitro and in vivo. Previous studies have shown that depletion of GGCT blocks the growth of MCF7 breast cancer cells via upregulation of the cyclin-dependent kinase inhibitor p21 (p21); in addition, induction of autophagy plays a role in the upregulation of p21 upon GGCT knockdown. However, the mechanisms underlying induction of p21 in cancer cells are not fully understood.

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This paper describes the geochemistry of groundwater and its flow system in the closed Yatani mine in southern Yamagata Prefecture, Japan. The mine is located in a sulfide deposit containing pyrite and has been generating acid mine drainage (AMD). The study was intended to elucidate the formation of AMD and its flow patterns using geological, hydrological, geochemical, and isotopic techniques.

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Article Synopsis
  • GGCT is an important enzyme for glutathione metabolism, and inhibiting it could be a new way to treat various cancers.
  • A study used immuno-histochemistry to check GGCT levels in bladder tumors and tested a new inhibitor called pro-GA's effect on bladder cancer cells, both alone and with another drug, mitomycin C.
  • Results showed that many bladder tumors had high GGCT levels, and pro-GA effectively reduced cancer cell growth while enhancing mitomycin C's anti-cancer effect, suggesting it could be a promising treatment strategy.
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Liver transplantation is the most effective treatment for treating liver cirrhosis. However, a limited number of donors, graft rejection, and other complications can undermine transplant success. It is considered that cell transplantation is an alternative approach of liver transplantation.

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