Publications by authors named "Yoshio Nishimura"

55 Publications

Structure-activity relationships of natural quinone vegfrecine analogs with potent activity against VEGFR-1 and -2 tyrosine kinases.

J Antibiot (Tokyo) 2021 Oct 20;74(10):734-742. Epub 2021 Jul 20.

Institute of Microbial Chemistry (BIKAKEN), Tokyo, Japan.

A series of analogs of vegfrecine, a natural quinone vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitor, was synthesized via oxidative amination of 2,5-dihydroxybenzamide with functionalized arylamine followed by ammonolysis and substitution of the quinone ring. The inhibitory activities of the analogs against the VEGFR-1 and -2 tyrosine kinases were assayed in vitro with the aim to identify a compound suitable to treat cancer and inflammatory diseases. Alterations of the functionality of the phenyl group, substitution of the quinone ring, and oxidative cyclization of the 1-carboxamide-2-aminoquinone moiety to form an isoxazole quinone ring were examined. Introduction of halo- and alkyl-substituents at the 5'-position of the phenyl ring resulted in potent inhibition of the VEGFR-1 and -2 tyrosine kinases. In particular, structural modification at C-5' on the phenyl ring was shown to significantly affect the selectivity of the inhibition between the VEGFR-1 and -2 tyrosine kinases. Compound 8, 5'-methyl-vegfrecine, showed superior selectivity toward the VEGFR-2 tyrosine kinase over the VEGFR-1 tyrosine kinase.
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http://dx.doi.org/10.1038/s41429-021-00445-yDOI Listing
October 2021

[Development of Efficient Synthetic Method for Tautomeric Dihydropyrimidines and Analysis of Their Functionality].

Authors:
Yoshio Nishimura

Yakugaku Zasshi 2021 ;141(2):151-161

Faculty of Pharmacy, Yasuda Women's University.

I here present the results of our studies on the synthesis and functional analysis of tautomeric dihydropyrimidines (DPs) and related compounds in two sections. In the first section, we describe our experimental and theoretical studies on the thermodynamics and properties of 2-substituted 1,4- and 1,6-dihydropyrimidine-5-carboxylates by H NMR measurements and density functional theory (DFT) calculations, respectively. The concentration ratios of tautomers a/b of DPs 1, 2, and 3 were determined under various conditions to determine the effects of temperature, solvent, and concentration on thermodynamics data. The obtained free energy differences (ΔG), enthalpy differences (ΔH), and entropy differences (ΔS) are discussed in terms of the molecular structures, dipole moments (DM), and electrostatic potential maps obtained by DFT calculations to clarify the nature of DPs 4-8. In the second section, an efficient synthetic method developed for 6-unsubstituted 3,4-dihydropyrimidin-2(1H)-thiones 9 and 2-ones 10 is described. The novelties of the synthesis protocol are as follows: 1) the use of Lewis acid-mediated reaction, 2) good to high yields, and 3) its broad scope of applicability to aldehydes and ureas. Hitherto unavailable 6-unsubstituted 2-amino DP 11 and 2-aryl DP 12 were obtained from 9 by a substitution reaction with the amine and the Liebeskind-Srogl reaction, respectively. The compounds 9, 10, and related 6-methyl derivatives 19-21 were assessed for their antiproliferative effect on the human promyelocytic leukemia cell line HL-60. 4,4-Dipropyl derivative 20 showed relatively strong activity with an IC value of 341 nM.
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http://dx.doi.org/10.1248/yakushi.20-00182DOI Listing
May 2021

Sixteen Different Types of Lipid-Conjugated siRNAs Containing Saturated and Unsaturated Fatty Acids and Exhibiting Enhanced RNAi Potency.

ACS Chem Biol 2021 01 21;16(1):150-164. Epub 2020 Dec 21.

Exploratory Oncology Research & Clinical Trial Center, National Cancer Center, Chiba 277-8577, Japan.

SiRNAs are strong gene-silencing agents that function in a target sequence-specific manner. Although siRNAs might one day be used in therapy for intractable diseases such as cancers, a number of problems with siRNAs must first be overcome. In this study, we developed 16 different types of lipid-conjugated siRNAs (lipid-siRNAs) that could effectively inhibit the expression of target genes. We determined the hybridization properties, cellular uptake efficacies, and RNAi potencies of the resulting lipid-siRNAs. The lipid-siRNAs exhibited a mild interaction with Lipofectamine RNAiMAX (LFRNAi) as a transfection reagent, and a high membrane permeability was observed in all lipid-siRNAs-LFRNAi complexes; the conjugate siRNAs composed of 16-18 carbon chains as fatty acids showed an especially good cellular uptake efficacy. The RNAi effect of lipid-siRNAs targeted to a β-catenin gene exhibited a strong RNAi potency compared with those of unmodified siRNAs. In particular, the conjugate siRNAs composed of 16-18 carbon chains as fatty acids showed excellent RNAi potencies with prolonged effectivities. Interestingly, the RNAi potencies of conjugate siRNAs containing 18 carbon chains with a -form (elaidic acid and -vaccenic acid) were inferior to those of the carbon chains with a -form (oleic acid and -vaccenic acid). These lipid-siRNAs can solve the many problems hindering the clinical application of siRNAs.
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http://dx.doi.org/10.1021/acschembio.0c00847DOI Listing
January 2021

Antitumor effect of palmitic acid-conjugated DsiRNA for colon cancer in a mouse subcutaneous tumor model.

Chem Biol Drug Des 2019 04 11;93(4):570-581. Epub 2019 Jan 11.

Department of Life Science, Faculty of Pharmacy, Yasuda Women's University, Hiroshima, Japan.

In this study, we synthesized Dicer-substrate siRNA conjugated with palmitic acid at the 5'-end of the sense strand (C16-DsiRNA), and examined its RNAi effect on β-catenin as a target gene in a colon cancer cell line, HT29Luc, both in vitro and in vivo. We examined the in vitro RNAi effect in HT29Luc cells and found that C16-DsiRNA strongly inhibited expression of the β-catenin gene in comparison with non-modified DsiRNA. Also, high membrane permeability of C16-DsiRNA was exhibited, and it was confirmed that most of the C16-DsiRNA was localized in cytoplasm of HT29Luc cells. In regard to the in vivo RNAi effect, C16-DsiRNA complexed with Invivofectamine targeting the β-catenin gene was locally administered to a subcutaneous tumor formed by implantation of HT29Luc cells into the subcutis of nude mice; we evaluated the effect by measuring the bioluminescence increase, which reflects tumor growth, using an in vivo imaging system. As a result, C16-DsiRNA strongly inhibited the growth of tumors formed in subcutis of nude mice compared with non-modified DsiRNA, and this in vivo RNAi effect lasted up to 15 days. Our results suggest that C16-DsiRNA should be vigorously pursued as a novel nucleic acid medicine for clinical treatment of cancer.
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http://dx.doi.org/10.1111/cbdd.13454DOI Listing
April 2019

Microbial metabolites and derivatives targeted at inflammation and bone diseases therapy: chemistry, biological activity and pharmacology.

J Antibiot (Tokyo) 2017 Nov 1. Epub 2017 Nov 1.

Institute of Microbial Chemistry (BIKAKEN), Tokyo, Japan.

Microbial metabolites have attracted increasing interest as a source of therapeutics and as probes for biological mechanisms. New microbial metabolites and derivatives targeted at inflammation and bone disease therapy have been identified by focusing on prostaglandin release, osteoblast differentiation and immune cell functions. These modulators of inflammatory processes and bone disease contribute to our understanding of biological mechanisms and support identification of the therapeutic potential of drug lead candidates. The present review describes recent advances in the chemistry and analysis of inhibitors of prostaglandin release or other functional molecules of immune cells, as well as inducers of osteoblast differentiation, including biological and pharmacological activities.The Journal of Antibiotics advance online publication, 1 November 2017; doi:10.1038/ja.2017.138.
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http://dx.doi.org/10.1038/ja.2017.138DOI Listing
November 2017

Phenazine carboxylic acid and its derivative induce osteoblast differentiation in preosteoblastic MC3T3-E1 cells but adipocyte differentiation in pluripotent mesenchymal C3H10T1/2 cells.

J Antibiot (Tokyo) 2017 Dec 25;70(12):1146-1149. Epub 2017 Oct 25.

Microbial Chemistry Research Foundation, Institute of Microbial Chemistry, Numazu Branch, Shizuoka, Japan.

Osteoblast and adipocyte are differentiated from mesenchymal stem cells and dysregulation of the differentiation might result in disease, such as osteoporosis and diabetes. To find small compounds that induce osteoblast differentiation, we screened an in-house natural compounds library with mouse preosteoblastic MC3T3-E1 cells using alkaline phosphatase (ALP) expression as an early osteoblast marker. We found that phenazine-1-carboxylic acid (PCA), one of the major phenazine derivatives produced by Pseudomonas, induced osteoblast differentiation in the cells at micromolar concentrations. PCA acted synergistically with an agonist of hedgehog signaling in inducing ALP activity in the cells. We also found that 2-hydroxy-PCA (2H-PCA) induced osteoblast differentiation in the cells but 2-methoxy-PCA and 1-hydroxy-phenazine did not. Unexpectedly, treatment of mouse pluripotent mesenchymal C3H10T1/2 cells with PCA or 2H-PCA induced an obvious morphological change. Oil Red O staining and real-time reverse-transcription PCR analysis revealed that PCA induced not osteoblast differentiation but adipocyte differentiation in C3H10T1/2 cells. These compounds could allow us to investigate the mechanism of osteoblast and adipocyte differentiation in the two model cell systems through a chemical biology approach.
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http://dx.doi.org/10.1038/ja.2017.129DOI Listing
December 2017

Silyl Ether as a Robust and Thermally Stable Dynamic Covalent Motif for Malleable Polymer Design.

J Am Chem Soc 2017 10 16;139(42):14881-14884. Epub 2017 Oct 16.

Department of Chemistry, University of California , Irvine, California 92697, United States.

Here we introduce silyl ether linkage as a novel dynamic covalent motif for dynamic material design. Through introduction of a neighboring amino moiety, we show that the silyl ether exchange rate can be accelerated by almost three orders of magnitude. By incorporating such silyl ether linkages into covalently cross-linked polymer networks, we demonstrate dynamic covalent network polymers displaying both malleability and reprocessability. The malleability of the networks is studied by monitoring stress relaxation at varying temperature, and their topology freezing temperatures are determined. The tunable dynamic properties coupled with the high thermal stability and reprocessability of silyl ether-based networks open doors to many potential applications for this family of materials.
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http://dx.doi.org/10.1021/jacs.7b08826DOI Listing
October 2017

Structure and antibacterial activities of new cyclic peptide antibiotics, pargamicins B, C and D, from Amycolatopsis sp. ML1-hF4.

J Antibiot (Tokyo) 2017 05 15;70(5):699-704. Epub 2017 Mar 15.

Laboratory of Microbiology, Institute of Microbial Chemistry (BIKAKEN), Tokyo, Japan.

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http://dx.doi.org/10.1038/ja.2017.34DOI Listing
May 2017

An iminosugar-based heparanase inhibitor heparastatin (SF4) suppresses infiltration of neutrophils and monocytes into inflamed dorsal air pouches.

Int Immunopharmacol 2016 Jun 22;35:15-21. Epub 2016 Mar 22.

Laboratory of Cancer Biology and Molecular Immunology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan; Department of Biochemistry, Juntendo University School of Medicine, 2-1-1, Hongo, Bunkyo-ku, Tokyo 104-8560, Japan; Department of Breast and Endocrine Surgery, Juntendo University School of Medicine, 2-1-1, Hongo, Bunkyo-ku, Tokyo 104-8560, Japan. Electronic address:

Local infiltration of inflammatory cells is regulated by a number of biological steps during which the cells likely penetrate through subendothelial basement membranes that contain heparan sulfate proteoglycans. In the present study, we examined whether administration of heparastatin (SF4), an iminosugar-based inhibitor of heparanase, could suppress local inflammation and degradation of heparan sulfate proteoglycans in basement membranes. In a carrageenan- or formyl peptide-induced dorsal air pouch inflammation model, the number of infiltrated neutrophils and monocytes was significantly lower in mice after topical administration of heparastatin (SF4). The concentration of chemokines MIP-2 and KC in pouch exudates of drug-treated mice was similar to control. In a zymosan-induced peritonitis model, the number of infiltrated cells was not altered in drug-treated mice. To further test how heparastatin (SF4) influences transmigration of inflammatory neutrophils, its suppressive effect on migration and matrix degradation was examined in vitro. In the presence of heparastatin (SF4), the number of neutrophils that infiltrated across a Matrigel-coated polycarbonate membrane was significantly lower, while the number of neutrophils passing through an uncoated membrane was not altered. Lysate of bone marrow-derived neutrophils released sulfate-radiolabeled macromolecules from basement membrane-like extracellular matrix, which was suppressed by heparastatin (SF4). Heparan sulfate degradation activity was almost completely abolished after incubation of lysate with protein G-conjugated anti-heparanase monoclonal antibody, strongly suggesting that the activity was due to heparanase-mediated degradation. Taken together, in a dorsal air pouch inflammation model heparastatin (SF4) potentially suppresses extravasation of inflammatory cells by impairing the degradation of basement membrane heparan sulfate.
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http://dx.doi.org/10.1016/j.intimp.2016.03.017DOI Listing
June 2016

Heparanase augments inflammatory chemokine production from colorectal carcinoma cell lines.

Biochem Biophys Res Commun 2016 Jan 20;469(4):878-83. Epub 2015 Dec 20.

Laboratory of Cancer Biology and Molecular Immunology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; Department of Biochemistry and Department of Breast and Endocrine Surgery, Juntendo University School of Medicine, 2-1-1, Hongo, Bunkyo-ku, Tokyo 104-8560, Japan. Electronic address:

To explore possible roles of heparanase in cancer-host crosstalk, we examined whether heparanase influences expression of inflammatory chemokines in colorectal cancer cells. Murine colorectal carcinoma cells incubated with heparanase upregulated MCP-1, KC, and RANTES genes and released MCP-1 and KC proteins. Heparanase-dependent production of IL-8 was detected in two human colorectal carcinoma cell lines. Addition of a heparanase inhibitor Heparastatin (SF4) did not influence MCP-1 production, while both latent and mature forms of heparanase augmented MCP-1 release, suggesting that heparanase catalytic activity was dispensable for MCP-1 production. In contrast, addition of heparin to the medium suppressed MCP-1 release in a dose-dependent manner. Similarly, targeted suppression of Ext1 by RNAi significantly suppressed cell surface expression of heparan sulfate and MCP-1 production in colon 26 cells. Taken together, it is concluded that colon 26 cells transduce the heparanase-mediated signal through heparan sulfate binding. We propose a novel function for heparanase independent of its endoglycosidase activity, namely as a stimulant for chemokine production.
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http://dx.doi.org/10.1016/j.bbrc.2015.12.074DOI Listing
January 2016

Expression and substrate range of Streptomyces vanillate demethylase.

Biol Pharm Bull 2014 9;37(9):1564-8. Epub 2014 Jul 9.

Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Yasuda Women's University.

Vanillate is converted to protocatechuate by an O-demethylase consisting of VanA and VanB in Streptomyces sp. NL15-2K. In this study, vanillate demethylase from this strain was functionally expressed in Escherichia coli, and its substrate range for vanillate analogs was determined by an in vivo assay using recombinant whole cells. Among aromatic methyl ethers, vanillate, syringate, m-anisate, and veratrate were good substrates, whereas ferulate, vanillin, and guaiacol were not recognized by Streptomyces vanillate demethylase. After vanillate, 4-hydroxy-3-methylbenzoate was a better substrate than m-anisate and veratrate, and the 3-methyl group was efficiently oxidized to a hydroxymethyl group. These observations suggest that the combination of a carboxyl group on the benzene ring and a hydroxyl group in the para-position relative to the carboxyl group may be preferable for substrate recognition by the enzyme. (1)H-NMR analysis showed that the demethylation product of veratrate was isovanillate rather than vanillate. Therefore, it was concluded that O-demethylation of veratrate by Streptomyces vanillate demethylase occurred only at the meta-position relative to the carboxyl group.
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http://dx.doi.org/10.1248/bpb.b14-00337DOI Listing
May 2015

Gene-silencing potency of symmetric and asymmetric lipid-conjugated siRNAs and its correlation with dicer recognition.

Bioconjug Chem 2013 Dec 9;24(12):2045-57. Epub 2013 Dec 9.

Faculty of Pharmacy, Yasuda Women's University , 6-13-1 Yasuhigashi, Asaminami-ku, Hiroshima 731-0153, Japan.

Three types of siRNAs and three types of left-overhang siRNAs (LoRNAs) were synthesized along with their conjugations with palmitic acid (C16) to investigate the correlation between Dicer recognition and gene-silencing potency. The siRNA types were composed of 21-nucleotide (nt), 23-nt, and 25-nt lengths of sense and antisense strands with a 2-nt overhang at each 3'-end. The three LoRNA types were composed of a 21-nt, a 23-nt, and a 25-nt length of sense strand with a 2-nt DNA at the 3'-blunt-end and a 23-nt, a 25-nt, and a 27-nt length of antisense strand with a 2-nt overhang at the 3'-end. Additionally, each of these siRNAs and LoRNAs was modified with a C16 at the 5'- or 3'-end of the sense strand; these were named C16-siRNAs and C16-LoRNAs, respectively. The siRNAs and C16-siRNAs were barely cleaved by Dicer, and their gene-silencing efficacies were not excellent, contrary to our expectations. In contrast, most of the LoRNAs and C16-LoRNAs became substrates of Dicer, and they showed both strong gene-silencing efficacies and high nuclease resistance. Among the LoRNAs, the 25D-C16/27-nt LoRNA, which is composed of a 25-nt sense strand with a 2-nt DNA conjugated with C16 at the 3'-end and a 27-nt antisense strand with a 2-nt overhang at the 3'-end, showed an excellent gene-silencing effect with high cell membrane permeability and strong resistance against nuclease degradation. Additionally, the Lo25D-C16/27RNA excelled in all three aspects, nuclease resistance, cell membrane permeability, and RNAi efficacy, compared with the cholesterol conjugation. We are certain that Lo25D-C16/27RNA can be useful as a new generation of RNAi molecules with which to overcome some of the limitations of RNAi technology.
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http://dx.doi.org/10.1021/bc400391nDOI Listing
December 2013

Alteration of the function of the UDP-glucuronosyltransferase 1A subfamily by cytochrome P450 3A4: different susceptibility for UGT isoforms and UGT1A1/7 variants.

Drug Metab Dispos 2014 Feb 19;42(2):229-38. Epub 2013 Nov 19.

Laboratory of Molecular Life Sciences (Y.Is., H.K., K.K., T.O., Y.Iw., S.T., Y.M., Y.N., N.E., H.Y.) and Laboratory of Medicinal Resource Regulation (F.T., S.M.), Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan; Biotechnology Research Center, Faculty of Engineering, Toyama Prefectural University, Imizu, Toyama, Japan (S.I.); Tohoku Pharmaceutical University, Sendai, Japan (K.N.); Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan (Y.Y.); and Department of Clinical Pharmacology, Flinders Medical Centre and Flinders University, Adelaide, Australia (P.I.M.).

Functional protein-protein interactions between UDP-glucuronosyltransferase (UGT)1A isoforms and cytochrome P450 (CYP)3A4 were studied. To this end, UGT1A-catalyzed glucuronidation was assayed in Sf-9 cells that simultaneously expressed UGT and CYP3A4. In the kinetics of UGT1A6-catalyzed glucuronidation of serotonin, both Michaelis constant (Km) and maximal velocity (Vmax) were increased by CYP3A4. When CYP3A4 was coexpressed with either UGT1A1 or 1A7, the Vmax for the glucuronidation of the irinotecan metabolite (SN-38) was significantly increased. S50 and Km both which are the substrate concentration giving 0.5 Vmax were little affected by simultaneous expression of CYP3A4. This study also examined the catalytic properties of the allelic variants of UGT1A1 and 1A7 and their effects on the interaction with CYP3A4. Although the UGT1A1-catalyzing activity of 4-methylumbelliferone glucuronidation was reduced in its variant, UGT1A1*6, the coexpression of CYP3A4 restored the impaired function to a level comparable with the wild type. Similarly, simultaneous expression of CYP3A4 increased the Vmax of UGT1A7*1 (wild type) and *2 (N129K and R131K), whereas the same was not observed in UGT1A7*3 (N129K, R131K, and W208R). In the kinetics involving different concentrations of UDP-glucuronic acid (UDP-GlcUA), the Km for UDP-GlcUA was significantly higher for UGT1A7*2 and *3 than *1. The Km of UGT1A7*1 and *3 was increased by CYP3A4, whereas *2 did not exhibit any such change. These results suggest that (1) CYP3A4 changes the catalytic function of the UGT1A subfamily in a UGT isoform-specific manner and (2) nonsynonymous mutations in UGT1A7*3 reduce not only the ability of UGT to use UDP-GlcUA but also CYP3A4-mediated enhancement of catalytic activity, whereas CYP3A4 is able to restore the UGT1A1*6 function.
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http://dx.doi.org/10.1124/dmd.113.054833DOI Listing
February 2014

Cytotoxicity of Vitex agnus-castus fruit extract and its major component, casticin, correlates with differentiation status in leukemia cell lines.

Int J Oncol 2013 Dec 9;43(6):1976-84. Epub 2013 Oct 9.

Department of Clinical Molecular Genetics, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan.

We have demonstrated that an extract from the ripe fruit of Vitex agnus-castus (Vitex) exhibits cytotoxic activities against various types of solid tumor cells, whereas its effects on leukemia cells has not been evaluated to date. In this study, the effects of Vitex and its major component, casticin, on leukemia cell lines, HL-60 and U-937, were investigated by focusing on proliferation, induction of apoptosis and differentiation. Identification and quantitation by NMR spectroscopy showed that casticin accounted for approximate 1% weight of Vitex. Dose-dependent cytotoxicity of Vitex and casticin was observed in both cell lines, and HL-60 cells were more sensitive to the cytotoxicity of Vitex/casticin compared to U-937 cells. Furthermore, compared to unstimulated HL-60 cells, phorbol 12-myristate 13-acetate (PMA)- and 1,25-dihydroxyvitamin D₃ (VD₃)-differentiated HL-60 cells acquired resistance to Vitex/casticin based on the results from cell viability and apoptosis induction analysis. Since the HL-60 cell line is more immature than the U-937 cell line, these results suggested that the levels of cytotoxicity of Vitex/casticin were largely attributed to the degree of differentiation of leukemia cells; that is, cell lines with less differentiated phenotype were more susceptible than the differentiated ones. RT-PCR analysis demonstrated that PMA upregulated the expression of intercellular adhesion molecule-1 (ICAM-1) in HL-60 cells, and that anti-ICAM-1 monoclonal antibody not only abrogated PMA-induced aggregation and adhesion of the cells but also restored its sensitivity to Vitex. These results suggested that ICAM-1 plays a crucial role in the acquired resistance in PMA-differentiated HL-60 cells by contributing to cell adhesion. These findings provide fundamental insights into the clinical application of Vitex/casticin for hematopoietic malignancy.
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http://dx.doi.org/10.3892/ijo.2013.2133DOI Listing
December 2013

Waldiomycin, a novel WalK-histidine kinase inhibitor from Streptomyces sp. MK844-mF10.

J Antibiot (Tokyo) 2013 Aug 1;66(8):459-64. Epub 2013 May 1.

Institute of Microbial Chemistry (BIKAKEN), Tokyo, Japan.

WalK, a histidine kinase, and WalR, a response regulator, make up a two-component signal transduction system that is indispensable for the cell-wall metabolism of low GC Gram-positive bacteria. WalK inhibitors are likely to show bactericidal effects against methicillin-resistant Staphylococcus aureus . We discovered a new WalK inhibitor, designated waldiomycin, by screening metabolites from actinomycetes. Waldiomycin belongs to the family of angucycline antibiotics and is structurally related to dioxamycin. Waldiomycin inhibits WalK from S. aureus and Bacillus subtilis at IC50s 8.8 and 10.2 μM, respectively, and shows antibacterial activity with MICs ranging from 4 to 8 μg ml(-1) against methicillin-resistant S. aureus and B. subtilis.
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http://dx.doi.org/10.1038/ja.2013.33DOI Listing
August 2013

NAD(P)H quinone oxidoreductase 1 (NQO1)-bioactivated pronqodine A regulates prostaglandin release from human synovial sarcoma cells.

J Nat Prod 2013 Apr 20;76(4):510-5. Epub 2013 Feb 20.

Institute of Microbial Chemistry (BIKAKEN), 3-14-23 Kamiosaki, Shinagawa-ku, Tokyo 141-0021, Japan.

Natural products have contributed to the elucidation of biological mechanisms as well as drug discovery research. Even now, the expectation for natural products is undiminished. We screened prostaglandin release inhibitors that had no effect on in vitro cyclooxygenase activity derived from natural product sources and discovered pronqodine A. Using spectral analysis and total synthesis, the structure of pronqodine A was shown to be a benzo[d]isothiazole-4,7-dione analogue. Evaluation of the biological activity of pronqodine A revealed that the NAD(P)H dehydrogenase quinone 1 (NQO1) converted pronqodine A into a two-electron reductive form. The reductive form underwent autoxidation and reversed to its native form immediately with the generation of reactive oxygen species. Further investigations proved that pronqodine A inhibited cyclooxygenase enzyme activity only in the presence of NQO1. Pronqodine A acts as a potential bioreductive compound, inhibiting prostaglandin release in selectively activated NQO1-expressing cells.
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http://dx.doi.org/10.1021/np300643fDOI Listing
April 2013

Vegfrecine, an inhibitor of VEGF receptor tyrosine kinases isolated from the culture broth of Streptomyces sp.

J Nat Prod 2013 Apr 15;76(4):715-9. Epub 2013 Feb 15.

Institute of Microbial Chemistry (BIKAKEN), Tokyo, 3-14-23 Kamiosaki, Shinagawa-ku, Tokyo 141-0021, Japan.

A new inhibitor of VEGF receptor tyrosine kinases, vegfrecine (1), was isolated from the culture broth of Streptomyces sp. MK931-CF8. The molecular structure of 1 was determined by NMR and MS analysis combined with synthesis. Compound 1 showed potent inhibitory activity against vascular endothelial growth factor receptor (VEGFR) tyrosine kinases in in vitro enzyme assays, but platelet-derived growth factor receptors (PDGFRs), fibroblast growth factor receptor (FGFR), and epidermal growth factor receptor (EGFR) responded only weakly. Compound 1 is a promising new selective VEGFR inhibitor for investigating new treatments of cancer and inflammatory diseases.
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http://dx.doi.org/10.1021/np300535cDOI Listing
April 2013

Amycolamicin: a novel broad-spectrum antibiotic inhibiting bacterial topoisomerase.

Chemistry 2012 Dec 5;18(49):15772-81. Epub 2012 Nov 5.

Institute of Microbial Chemistry, BIKAKEN, Tokyo, Japan.

The abuse of antibacterial drugs imposes a selection pressure on bacteria that has driven the evolution of multidrug resistance in many pathogens. Our efforts to discover novel classes of antibiotics to combat these pathogens resulted in the discovery of amycolamicin (AMM). The absolute structure of AMM was determined by NMR spectroscopy, X-ray analysis, chemical degradation, and modification of its functional groups. AMM consists of trans-decalin, tetramic acid, two unusual sugars (amycolose and amykitanose), and dichloropyrrole carboxylic acid. The pyranose ring named as amykitanose undergoes anomerization in methanol. AMM is a potent and broad-spectrum antibiotic against Gram-positive pathogenic bacteria by inhibiting DNA gyrase and bacterial topoisomerase IV. The target of AMM has been proved to be the DNA gyrase B subunit and its binding mode to DNA gyrase is different from those of novobiocin and coumermycin, the known DNA gyrase inhibitors.
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http://dx.doi.org/10.1002/chem.201202645DOI Listing
December 2012

ATP serves as an endogenous inhibitor of UDP-glucuronosyltransferase (UGT): a new insight into the latency of UGT.

Drug Metab Dispos 2012 Nov 30;40(11):2081-9. Epub 2012 Jul 30.

Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.

We have suggested that adenine-related compounds are allosteric inhibitors of UGT in rat liver microsomes (RLM) treated with detergent. To clarify whether the same occurs with a pore-forming peptide, alamethicin, the effects of adenine-related compounds on 4-metylumbelliferone (4-MU) glucuronidation were examined using RLM and human liver microsomes (HLM). ATP inhibited 4-MU glucuronidation when polyoxyethylene cetyl alcohol ether (Brij-58)-treated RLM were used (IC(50) = approximately 70 μM). However, alamethicin-treated RLM exhibited a lower susceptibility (IC(50) = approximately 460 μM) than Brij-58-treated RLM. A similar phenomenon was observed when pooled HLM were used. Then, the endogenous ATP content of RLM was determined in the presence and absence of alamethicin or detergent, and although no ATP remained in the microsomal pellets after Brij-58 treatment, more than half of the microsomal ATP remained even after treatment with alamethicin. Furthermore, the V(max) in the absence of an adenine-related compound was approximately three times higher in Brij-58-treated than in alamethicin-treated RLM. The difference in the inhibitory potency observed was due to the difference in remaining endogenous ATP and the accessibility of exogenous ATP to the luminal side of the endoplasmic reticulum (ER), where the active site of UDP-glucuronosyltransferase (UGT) is located. Gefitinib (Iressa), a protein tyrosine kinase inhibitor, markedly inhibited human UGT1A9 activity. It is interesting to note that AMP antagonized Gefitinib-provoked inhibition of UGT1A9, and ATP exhibited an additive inhibitory effect at a lower concentration. Therefore, Gefitinib inhibits UGT1A9 at the common ATP-binding site shared with ATP and AMP. Releasing adenine nucleotide from the ER is suggested to be one of the mechanisms that explain the "latency" of UGT.
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http://dx.doi.org/10.1124/dmd.112.046862DOI Listing
November 2012

Decalpenic acid induces early osteoblastic markers in pluripotent mesenchymal cells via activation of retinoic acid receptor γ.

Biochem Biophys Res Commun 2012 Jun 19;422(4):751-7. Epub 2012 May 19.

Institute of Microbial Chemistry, Tokyo, 3-14-23 Kamiosaki, Tokyo 141-0021, Japan.

Decalpenic acid is a natural small molecule previously isolated from the fermentation broth of fungi that induces early osteoblastic markers in pluripotent mesenchymal cells. Treatment of mouse pluripotent mesenchymal C3H10T1/2 cells with decalpenic acid gave rise to a morphological change similar to that induced by the treatment with retinoic acid, i.e. the cells adopted a more elongated spindle shape. Using a retinoic acid response element reporter and receptor activity assays, we show that decalpenic acid is a new retinoid with selectivity towards retinoic acid receptors γ and α. The induction of early osteoblastic markers by decalpenic acid was significantly inhibited by treatment with the retinoid antagonist, LE540, or with small interfering RNA-mediated knockdown of retinoic acid receptor γ. These results demonstrated that decalpenic acid induces early osteoblastic markers in pluripotent mesenchymal cells through activation of retinoic acid receptor γ.
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http://dx.doi.org/10.1016/j.bbrc.2012.05.075DOI Listing
June 2012

λ5-Phospha[7]helicenes: synthesis, properties, and columnar aggregation with one-way chirality.

Angew Chem Int Ed Engl 2012 Jan 1;51(3):695-9. Epub 2011 Dec 1.

Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyoku, Tokyo 113-8656, Japan.

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http://dx.doi.org/10.1002/anie.201106157DOI Listing
January 2012

Synthetic studies on novel 1,4-dihydro-2-methylthio-4,4,6-trisubstituted pyrimidine-5-carboxylic acid esters and their tautomers.

Chem Pharm Bull (Tokyo) 2011 ;59(12):1458-66

Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Yasuda Women's University, Hiroshima 731–0153, Japan.

A mixture of alkyl 1,4-dihydro-2-methylthio-4,4,6-trisubstituted pyrimidine-5-carboxylate 1 and its tautomeric isomer, alkyl 1,6-dihydro-2-methylthio-4,6,6-trisubstituted pyrimidine-5-carboxylate 2 is synthesized by the Atwal-Biginelli cyclocondensation reaction of S-methylisothiourea hemisulfate salt 3 with 2-(gem-disubstituted)methylene-3-oxoesters 4 that can be accessed by the Lehnert procedure for the Knoevenagel-type condensation. The structures of the tautomeric products of the Atwal-Biginelli cyclocondensation reaction, 1 and 2, which are inseparable from each other, are determined unambiguously by (1)H-NMR spectroscopy at various temperatures and nuclear Overhauser enhancement spectroscopy (NOESY) experiment. Because these dihydropyrimidine products are otherwise inaccessible and thus hitherto unavailable, the synthetic methods established in this study will help to expand the molecular diversity of their related derivatives.
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http://dx.doi.org/10.1248/cpb.59.1458DOI Listing
March 2012

Characterization of two isozymes of coniferyl alcohol dehydrogenase from Streptomyces sp. NL15-2K.

Biosci Biotechnol Biochem 2011 7;75(9):1770-7. Epub 2011 Sep 7.

Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Yasuda Women's University.

We purified two isozymes of coniferyl alcohol dehydrogenase (CADH I and II) to homogeneity from cell-free extracts of Streptomyces sp. NL15-2K. The apparent molecular masses of CADH I and II were determined to be 143 kDa and 151 kDa respectively by gel filtration, whereas their subunit molecular masses were determined to be 35,782.2 Da and 37,597.7 Da respectively by matrix-assisted laser-desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Thus, it is probable that both isozymes are tetramers. The optimum pH and temperature for coniferyl alcohol dehydrogenase activity were pH 9.5 and 45 °C for CADH I and pH 8.5 and 40 °C for CADH II. CADH I oxidized various aromatic alcohols and allyl alcohol, and was most efficient on cinnamyl alcohol, whereas CADH II exhibited high substrate specificity for coniferyl alcohol, and showed no activity as to the other alcohols, except for cinnamyl alcohol and 3-(4-hydroxy-3-methoxyphenyl)-1-propanol. In the presence of NADH, CADH I and II reduced cinnamaldehyde and coniferyl aldehyde respectively to the corresponding alcohols.
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http://dx.doi.org/10.1271/bbb.110301DOI Listing
January 2012

Tripropeptin C blocks the lipid cycle of cell wall biosynthesis by complex formation with undecaprenyl pyrophosphate.

Antimicrob Agents Chemother 2011 Aug 31;55(8):3821-8. Epub 2011 May 31.

Drug Development Unit, Bioactive Molecule Research Group, Laboratory of Disease Biology, Institute of Microbial Chemistry, Tokyo, Japan.

Tripropeptin C (TPPC) is a naturally occurring cyclic lipodepsipeptide antibiotic produced by a Lysobacter sp. TPPC exhibits potent antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and penicillin-resistant Streptococcus pneumoniae. This antibiotic also inhibits the incorporation of N-acetylglucosamine into the peptidoglycan of S. aureus at a 50% inhibitory concentration (IC(50)) of 0.7 μM, which is proportional to its MIC (0.87 μM; equivalent to 1.0 μg/ml). Treatment of exponential-phase S. aureus cells with TPPC resulted in accumulation of UDP-MurNAc-pentapeptide in the cytoplasm. The antimicrobial activity of TPPC was weakened by the addition of prenyl pyrophosphates but not by prenyl phosphates, UDP-linked sugars, or the pentapeptide of peptidoglycan. The direct interaction between TPPC and undecaprenyl pyrophosphate (C(55)-PP) was observed by mass spectrometry and thin-layer chromatography analysis, indicating that TPPC can potentially inhibit C(55)-PP phosphatase activity, which plays a crucial role in the lipid cycle of peptidoglycan synthesis. As expected, TPPC inhibits this enzymatic reaction at an IC(50) of 0.03 to 0.1 μM in vitro, as does bacitracin. From the analysis of accumulation of lipid carrier-related compounds, TPPC was found to cause the accumulation of C(55)-PP in situ, leading to the accumulation of a glycine-containing lipid intermediate. This suggested that the TPPC/C(55)-PP complex also inhibits the transglycosylation step or flippase activity, adding to the inhibition of C(55)-PP dephosphorylation. This mode of action is different from that of currently available drugs such as vancomycin, daptomycin, and bacitracin.
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http://dx.doi.org/10.1128/AAC.00443-11DOI Listing
August 2011

Photodegradation of target oligosaccharides by light-activated small molecules.

Angew Chem Int Ed Engl 2010 Dec;49(52):10096-100

Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.

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http://dx.doi.org/10.1002/anie.201005161DOI Listing
December 2010

Decalpenic acid, a novel small molecule from Penicillium verruculosum CR37010, induces early osteoblastic markers in pluripotent mesenchymal cells.

J Antibiot (Tokyo) 2010 Dec 13;63(12):703-8. Epub 2010 Oct 13.

Institute of Microbial Chemistry, Shinagawa-ku, Tokyo, Japan.

Osteoblasts are the cells responsible for bone formation during embryonic development and adult life. Small compounds that could induce osteoblast differentiation might be promising sources of therapies for bone diseases such as osteoporosis. During screening for inducers of osteoblast differentiation of mouse pluripotent mesenchymal C3H10T1/2 cells, we isolated a small compound from the fermentation broth of Penicillium verruculosum CR37010. This compound, named decalpenic acid, bears a decalin moiety with a tetraenoic acid side chain. Treatment of C3H10T1/2 cells with decalpenic acid alone induced the expression of early osteoblast markers, such as alkaline phosphatase activity and osteopontin mRNA, but did not induce the late osteoblast marker osteocalcin mRNA or adipocyte markers under our experimental conditions.
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http://dx.doi.org/10.1038/ja.2010.114DOI Listing
December 2010

Isolation and structure elucidation of a novel androgen antagonist, arabilin, produced by Streptomyces sp. MK756-CF1.

J Antibiot (Tokyo) 2010 Oct 25;63(10):601-5. Epub 2010 Aug 25.

Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, Yokohama, Japan.

In the course of screening for a new type of androgen receptor (AR) antagonist, we isolated a novel compound, arabilin, with two structural isomers, spectinabilin and SNF4435C, produced by Streptomyces sp. MK756-CF1. Structure elucidation on the basis of the spectroscopic properties showed that arabilin is a novel polypropionate-derived metabolite with a p-nitrophenyl group and a substituted γ-pyrone ring. Arabilin competitively blocked the binding of androgen to the ligand-binding domain of AR in vitro. In addition, arabilin inhibited androgen-induced prostate-specific antigen mRNA expression in prostate cancer LNCaP cells.
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http://dx.doi.org/10.1038/ja.2010.98DOI Listing
October 2010

Biological activities of pargamicin A, a novel cyclic peptide antibiotic from Amycolatopsis sp.

J Antibiot (Tokyo) 2010 Jun 26;63(6):279-83. Epub 2010 Mar 26.

Drug Development Unit, Microbial Chemistry Research Center, Shinagawa-ku, Tokyo, Japan.

The time-kill studies using pargamicin A against Staphylococcus aureus and Enterococcus faecalis were performed. The effects of the incorporation of radioactive precursors into macromolecules, membrane potential and function using fluorescent dyes were also examined. These studies revealed that rapid bactericidal activity of pargamicin A correlates with the perturbation of bacterial cell membrane potential and membrane function.
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http://dx.doi.org/10.1038/ja.2010.29DOI Listing
June 2010
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