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Hidenori Watanabe

Publications and source records attributed to Hidenori Watanabe.

14 recordsLinked to original sources
PubMed2006

Synthesis of gerfelin and related analogous compounds.

Gerfelin, an inhibitor of human geranylgeranyl diphosphate (GGPP) synthase that has been isolated from a culture broth of Beauveria felina QN22047, was synthesized in 4 and 3 steps starting from 2,4-dihydroxy-6-methylbenzoic acid and 3,4,5-trihydroxytoluene, respectively. An effective ligand, 2-(di-tert-butylphosphino)biphenyl, was used in the palladium-catalyzed diaryl ether-forming reaction. Five analogous compounds of gerfelin were also synthesized for a study of the structure-activity relationship.

Biphenyl Compounds↗
PubMed2006

Simple synthesis of enantiomerically pure sauriols A and B.

Sauriols A and B belong to a class of diarylbutane-lignans and exhibit antifeedant activity. We succeeded in the first synthesis of sauriols A and B by using a simple and efficient asymmetric dimerization of a cinnamic acid derivative as the key step.

Cinnamates↗
PubMed2005

Screening of putative oxygenase genes in the Fusarium graminearum genome sequence database for their role in trichothecene biosynthesis.

In the biosynthesis of type B trichothecenes, four oxygenation steps remain to have genes functionally assigned to them. On the basis of the complete genome sequence of Fusarium graminearum, expression patterns of all oxygenase genes were investigated in Fusarium asiaticum (F. graminearum lineage 6). As a result, we identified five cytochrome P450 monooxygenase (CYP) genes that are specifically expressed under trichothecene-producing conditions and are unique to the toxin-producing strains. The entire coding regions of four of these genes were identified in F. asiaticum. When expressed in Saccharomyces cerevisiae, none of the oxygenases were able to transform trichodiene-11-one to expected products. However, one of the oxygenases catalyzed the 2beta-hydroxylation rather than the expected 2alpha-hydroxylation. Targeted disruption of the five CYP genes did not alter the trichothecene profiles of F. asiaticum. The results are discussed in relation to the presence of as-yet-unidentified oxygenation genes that are necessary for the biosynthesis of trichothecenes.

DNA, Fungal↗
PubMed2005

Chemistry and biology of moverastins, inhibitors of cancer cell migration, produced by Aspergillus.

Cancer cell migration is a required step in cancer metastasis. We screened for inhibitors of cancer cell migration of microbial origin, and obtained moverastin, a member of the cylindrol family, from Aspergillus sp. F7720. However, the results of an NMR spectroscopic analysis raised the possibility that moverastin is a mixture of two diastereomers. Separation of the C-10 epimers of synthetic moverastin and a bioassay revealed that both diastereomers (moverastins A and B) had inhibitory effects on cell migration. Furthermore, we demonstrated that moverastins A and B inhibited FTase in vitro, and they also inhibited both the membrane localization of H-Ras and the activation of the PI3K/Akt pathway in EC17 cells. Thus, moverastins inhibited the migration of tumor cells by inhibiting the farnesylation of H-Ras, and subsequent H-Ras-dependent activation of the PI3K/Akt pathway.

Alkyl and Aryl Transferases↗
PubMed2005

Prunustatin A, a novel GRP78 molecular chaperone down-regulator isolated from Streptomyces violaceoniger.

In the course of our screening program for regulators of a molecular chaperone GRP78 expression, we isolated a novel inhibitor of GRP78 expression, designated as prunustatin A, from Streptomyces violaceoniger 4521-SVS3. The structure of prunustatin A was determined by a series of NMR analyses to be an oxidized type of the neoantimycin family. Prunustatin A inhibited the expression of GRP78 induced by 2-deoxyglucose in human fibrosarcoma HT1080 cells accompanied by global cell death without showing cytotoxicity under normal nutrient condition.

Cell Line↗
PubMed2004

Synthesis and structure-activity relationships of 5,6,7,8-tetrahydro-4H-thieno[3,2-b]azepine derivatives: novel arginine vasopressin antagonists.

A variety of novel heterocyclic compounds having thienoazepine, pyrroloazepine, furoazepine, and thienodiazepine skeletons were synthesized, most of which exhibited potent antagonism of [(3)H]-AVP specific binding in assays using rat liver (V1), rat kidney (V2), human platelet plasma membranes, and recombinant human CHO cells (V2), as well as antagonizing AVP-induced hypertension in rats (V1, intravenous) and showing a diuretic effect in rats (V2, oral). By detailed studies of the structure-activity relationships of these compounds, the thienoazepine derivative 1 was found to be a very potent combined V1 and V2 antagonist. After further pharmacological and toxicological evaluation as well as physical properties, the hydrochloride 2 (JTV-605) of compound 1 was selected for clinical studies as a potent AVP antagonist with a long duration of action.

Animals↗
PubMed2004

The anticancer natural product pironetin selectively targets Lys352 of alpha-tubulin.

Pironetin is a potent inhibitor of tubulin assembly and arrests cell cycle progression in M phase. Analyses of its structure-activity relationships suggested that pironetin covalently binds tubulin. To determine the binding site of pironetin, we synthesized biotinylated pironetin, which inhibited tubulin assembly both in vitro and in situ. The biotinylated pironetin selectively and covalently bound with tubulin. Partial digestion of biotinylated pironetin-treated tubulin by several proteases revealed that the binding site is the C-terminal portion of alpha-tubulin. By systematic alanine scanning, the pironetin binding site was determined to be Lys352 of alpha-tubulin. Lys352 is located at the entrance of a small pocket of alpha-tubulin, and this pocket faces the beta-tubulin of the next dimer. This is the first compound that covalently binds to the alpha subunit of tubulin and Lys352 of alpha-tubulin and inhibits the interaction of tubulin heterodimers.

Amino Acid Sequence↗
PubMed2004

An odorant derivative as an antagonist for an olfactory receptor.

Different odorants are recognized by different combinations of G protein-coupled olfactory receptors, and thereby, odor identity is determined by a combinatorial receptor code for each odorant. We recently demonstrated that odorants appeared to compete for receptor sites to act as an agonist or an antagonist. Therefore, in natural circumstances where we always perceive a mixture of various odorants, olfactory receptor antagonism between odorants may result in a receptor code for the mixture that cannot be predicted from the codes for its individual components. Here we show that stored isoeugenol has an antagonistic effect on a mouse olfactory receptor, mOR-EG. However, freshly purified isoeugenol did not have an inhibitory effect. Instead, an isoeugenol derivative produced during storage turned out to be a potent competitive antagonist of mOR-EG. Structural analysis revealed that this derivative is an oxidatively dimerized isoeugenol that naturally occurs by oxidative reaction. The current study indicates that as odorants age, they decompose or react with other odorants, which in turn affects responsiveness of an olfactory receptor(s).

Calcium↗
PubMed2004

Structure of tyroscherin, an antitumor antibiotic against IGF-1-dependent cells from Pseudallescheria sp.

An antitumor antibiotic, tyroscherin, was isolated from the culture of a fungus identified as Pseudallescheria sp. The structure of tyroscherin including the absolute stereochemistry was determined as shown in Fig. 1 by NMR and degradation studies. Tyroscherin selectively inhibited IGF-1-dependent growth of MCF-7 human breast cancer cells with an IC50 of 9.7 ng/ml.

Antibiotics, Antineoplastic↗
PubMed2002

Short-step syntheses of all stereoisomers of preussin and their bioactivities.

All the eight stereoisomers of (+)-preussin (1b), an antifungal agent inhibiting the growth of fission yeast and human cancer cells, were synthesized in two steps by non-stereoselective reactions and chromatographic separation, starting from L- and D-N-protected-phenylalaninal (2). Their bioassay revealed all of the stereoisomers to be almost equally bioactive.

Anisomycin↗