Publications by authors named "Siro Simizu"

Vasculogenic mimicry (VM) is a process by which tumor cells form vessel-like network to secure oxygen and nutrients essential for tumor growth. Intercellular junctions, including tight junctions, may play a critical role in this process, important for VM. Here, we investigated the role of angulin-1/LSR (Ang-1), a key component of tricellular tight junctions, in VM regulation.

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C-mannosylation is a protein glycosylation that regulates the functions of target proteins. Although it has been reported that a disintegrin and metalloproteinase with thrombospondin motifs 1 (ADAMTS1), an important spermatogenesis factor, is C-mannosylated, the roles of C-mannosylation in ADAMTS1 in testicular cells are still unclear. In this study, we found that ADAMTS1 is C-mannosylated at Trp and Trp in testis germ NEC8 cells.

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The total synthesis of isodaphlongamine H based on a lactam strategy, which enables quick access to complex cyclic amines, is described. The strategy begins with alkylation of a chiral lactam and subsequent N-oxidation via an imino ether to afford the N-hydroxylactam. For the key transformation to functionalize the amide carbonyl, an iridium-catalyzed reductive [3 + 2] cycloaddition of the N-hydroxylactam provides a tricyclic isoxazolidine in a one-pot process.

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C-mannosylation is a unique type of glycosylation in which a mannose is added to tryptophan in a protein. However, the biological function of C-mannosylation is still largely unknown. AXL is a receptor tyrosine kinase, and its overexpression contributes to tumor malignancy.

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Article Synopsis
  • Ecological surveys using environmental DNA (eDNA) from water samples are promising but typically require lab analysis with advanced technology.* -
  • This study introduces a simplified method for detecting genes from cell-containing environmental waters using gene sensor arrays that do not need DNA labeling or special training.* -
  • The developed sensor array demonstrated strong, specific responses to target DNA from environmental samples, successfully detecting DNA from cells in river water at a concentration relevant to natural conditions.*
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Natural linear polyamines play diverse roles in physiological processes by interacting with receptors at the cellular level. Herein, we describe the stereodivergent synthesis of oligopyrrolidines, which are conformationally constrained polyamines. We synthesized dimeric and trimeric 2-oxo-oligopyrrolidines using an iterative coupling strategy.

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-mannosylation is a post-translational modification that occurs intracellularly in the endoplasmic reticulum. In humans, biosynthesis of -mannosylation in proteins containing thrombospondin type 1 repeat is catalyzed by the DPY19 family; nonetheless, biological functions of protein -mannosylation are not yet fully understood, especially in tumor progression. Vasculogenic mimicry (VM) is the formation of fluid-conducting channels by highly invasive and genetically deregulated tumor cells, enabling the tumors to form matrix-embedded vasculogenic structures, containing plasma and blood cells to meet the metabolic demands of rapidly growing tumors.

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Article Synopsis
  • Basidalin, derived from the mushroom Leucoagaricus naucina, shows strong antiproliferative effects against human cancer cell lines, building on its known antibacterial and antitumor properties in murine models.
  • The study highlights that basidalin’s anticancer action is linked to the induction of autophagy, with increased LC3-II levels and enhanced autophagic flux occurring independently of mTOR pathways.
  • Additionally, the effectiveness of basidalin and its analogs in combating cancer cells is tied to their structural features, specifically a formyl group that influences their ability to induce autophagy and inhibit cell growth.
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DNA analysis in water samples is attracting attention in various fields. However, conventional methods for DNA analysis require a work-intensive and time-consuming sample pre-treatment. In this study, a simplified pre-treatment method for analyzing DNA in water samples was evaluated.

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Premelanosome protein (PMEL), a melanocyte-specific glycoprotein, has an essential role in melanosome maturation, assembling amyloid fibrils for melanin deposition. PMEL undergoes several post-translational modifications, including N- and O-glycosylations, which are associated with proper melanosome development. C-mannosylation is a rare type of protein glycosylation at a tryptophan residue that might regulate the secretion and localization of proteins.

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Long interspersed nuclear element-1 (LINE-1, L1) affects the transcriptome landscape in multiple ways. Promoter activity within its 5'UTR plays a critical role in regulating diverse L1 activities. However, the epigenetic status of L1 promoters in adult brain cells and their relationship with psychiatric disorders remain poorly understood.

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Vasculogenic mimicry (VM) is the formation of microvascular channels by cancer cells. VM requires cellular processes that are regulated by changes in cellular migration and morphology. Cofilin (CFL), a key regulator of actin depolymerization, has been reported to affect malignant phenotypes of cancer.

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C-mannosylation is a rare type of protein glycosylation whereby a single mannose is added to the first tryptophan in the consensus sequence Trp-Xaa-Xaa-Trp/Cys (in which Xaa represents any amino acid). Its consensus sequence is mainly found in proteins containing a thrombospondin type-1 repeat (TSR1) domain and in type I cytokine receptors. In these proteins, C-mannosylation affects protein secretion, intracellular localization, and protein stability; however, the role of C-mannosylation in proteins that are not type I cytokine receptors and/or do not contain a TSR1 domain is less well explored.

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C-mannosylation is a unique type of protein glycosylation via C-C linkage between an α-mannose and a tryptophan residue. This modification has been identified in about 30 proteins and regulates several functions, such as protein secretion and intracellular localization, as well as protein stability. About half of C-mannosylated proteins are categorized as proteins containing thrombospondin type 1 repeat domain or type I cytokine receptors.

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Caldorazole () was isolated from the marine cyanobacterium sp. collected on Ishigaki Island, Okinawa, Japan. Its structure was determined to be a new polyketide that contained two thiazole rings and an -methylenolpyruvamide moiety.

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Africane-type sesquiterpenoids are a unique tricyclic carbon architecture sesquiterpenoid isolated as natural products. Δ -africanene has been reported to exhibit anti-inflammatory activity for carrageenan-induced rat foot edema. In this study, we reported structure-activity relationship study of africane-type sesquiterpenoids and found that some africane-type sesquiterpenoid analogs and their synthetic intermediate showed potent anti-inflammatory activity.

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Melanoma is a type of skin cancer that derives from melanocytes; this tumor is highly metastatic and causes poor clinical outcomes in patients. Vasculogenic mimicry (VM), a vascular-like network that is formed by tumor cells instead of endothelial cells, promotes the growth and metastasis of tumors by providing tumors with oxygen- and nutrient-containing blood. VM correlates with a poor prognosis in patients with melanoma, but the melanoma-specific mechanisms of VM are unknown.

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Humulanolides are natural products isolated from Asteriscus, and the isolation and total synthesis of many types of humulanolides have been reported. In this study, we evaluated anti-proliferative activity of twelve humulanolides against various human cancer cell lines and found that humulanolide analog E, which was newly designed and synthesized, exhibited the highest anti-proliferative activity. Structure-activity relationship analysis revealed that α,β-unsaturated carbonyl moieties in humulanolides play an important role for anti-proliferative activity.

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Practical total syntheses of africane-type sesquiterpenoids were realized by reexamination of a divergent strategy employing optimized three-component coupling followed by ring-closing metathesis and substrate-controlled cyclopropanation. This sequential eight-step conversion provided Δ -africanene, a common bicyclo[5.3.

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ErbB4 is a member of the ErbB receptor tyrosine kinase family. It has both pro- and anti-oncogenic activities in tumors. Vasculogenic mimicry (VM), a phenomenon in which cancer cells form capillary-like structures without endothelial cells, has been recognized to be a cause of malignant phenotypes in some solid tumors.

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Vasculogenic mimicry (VM) is the formation of a blood supply system that confers aggressive and metastatic properties to tumors and correlates with a poor prognosis in cancer patients. Thus, the inhibition of VM is considered an effective approach for cancer treatment, although such a mechanism remains poorly described. In the present study, we examined methionine aminopeptidase‑2 (MetAP2), a key factor of angiogenesis, and demonstrated that it is pivotal for VM, using pharmacological and genetic approaches.

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DPY19L3 has been identified as a -mannosyltransferase for thrombospondin type-1 repeat domain-containing proteins. In this study, we focused on the role of DPY19L3 in the myogenic differentiation of C2C12 mouse myoblast cells. We carried out DPY19L3 gene depletion using the CRISPR/Cas9 system.

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