論文 - 荒井　緑

Acoschimperoside P, 2 '-acetate: a Hedgehog signaling inhibitory constituent from Vallaris glabra

Yusnita Rifai, Midori A. Arai, Takashi Koyano, Thaworn Kowithayakorn, Masami Ishibashi

JOURNAL OF NATURAL MEDICINES （SPRINGER TOKYO）  65 （ 3-4 ） 629 - 632 2011年07月

査読有り,  ISSN  1340-3443

　概要を見る

Complete (1)H and (13)C NMR assignments of acoschimperoside P, 2'-acetate (1) and a new cardiac glycoside (2), isolated from the leaves of Vallaris glabra, are described. Compound 1 was active in the assay for Hedgehog signaling inhibition. In further experiments, this compound showed a strong cytotoxicity against human pancreatic (PANC1) and human prostate (DU145) cancer cells. The expression of GLI-related proteins (PTCH and BCL-2) in a dose-dependent manner was also inhibited by 1.

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Approaches to Neural Stem Cells and Cancer Cells Based on Natural Products

Midori A. Arai

CHEMICAL & PHARMACEUTICAL BULLETIN （PHARMACEUTICAL SOC JAPAN）  59 （ 4 ） 417 - 426 2011年04月

査読有り,  ISSN  0009-2363

　概要を見る

We have developed "protein- and cell-based screen methods" for the isolation of new natural products. By using VDR (vitamin D receptor) immabilized magnetic beads, two new natural products were isolated rapidly. To find inhibitors of Hes1 protein, which is one of the important transcriptional factors in neural stem cells, a Hes1 dimer plate assay was developed, and then first Hes1 dimer inhibitors were found from our natural products library. As a "cell-based screen method," a reporter gene assay for screening Hh (hedgehog) signaling inhibitors was constructed. New Hh signaling inhibitors were isolated from our natural extracts library. We evaluated their Hh inhibitory activity in Hh related protein synthesis and cytotoxicity against cancers, in which Hh signaling is aberrantly activated. In addition to the naturally made compounds library (extracts library), "small molecules based on natural products" were synthesized. The total synthesis of Melleumin A, B, which were isolated by our group, was achieved. From their synthetic derivatives, inhibitors of the Wnt signal, which has been reported to cause colon cancers, were discovered. Moreover, flavanone and chromone were selected as natural product scaffolds. Many flavonoids and chromones with diverse heterocyclic units were constructed using our efficient synthetic method.

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Cycloartane Triterpenes Isolated from Combretum quadrangulare in a Screening Program for Death-Receptor Expression Enhancing Activity

Toume, Kazufumi, Nakazawa, Takafumi, Ohtsuki, Takashi, Arai, Midori A., Koyano, Takashi, Kowithayakorn, Thaworn, Ishibashi, Masami

JOURNAL OF NATURAL PRODUCTS （AMER CHEMICAL SOC）  74 （ 2 ） 249 - 255 2011年02月

査読有り,  ISSN  0163-3864

　概要を見る

In our screening program for natural products that increase DR5 (death-receptor 5) expression, nine new cycloartane triterpenes, combretanones A-G (1-7), combretic acid A (8), and combretic acid B (9), were isolated from a MeOH extract of Combretum quadrangulare leaves. The known oleanane triterpenes (10, 11) and six known flavonols (12-17) were also isolated. The structures of 1-9 were elucidated by spectroscopic studies. Compounds 7, 9, 12, 16, and 17 enhanced DRS expression, and 16 showed TRAIL-resistance abrogating activity.

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Tubiferic Acid, a New 9,10-Secocycloartane Triterpenoid Acid Isolated from the Myxomycete Tubulifera arachnoidea

Yukihito Ippongi, Takashi Ohtsuki, Kazufumi Toume, Midori A. Arai, Yukinori Yamamoto, Masami Ishibashi

CHEMICAL & PHARMACEUTICAL BULLETIN （PHARMACEUTICAL SOC JAPAN）  59 （ 2 ） 279 - 281 2011年02月

査読有り,  ISSN  0009-2363

　概要を見る

Tubiferic acid (1), a new triterpenoid acid having a 2,6-dimethyl-4,5-dihydroxy-2-hexenoic acid moiety as a side chain, was isolated from field-collected fruit bodies of the myxomycete Tubulifera arachnoidea, and its structure was elucidated by spectral data. Tubiferic acid (1) had the same unique 9,10-secocycloartane carbon skeleton as tubiferal A (2).

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2-Methoxy-1,4-naphthoquinone isolated from Impatiens balsamina in a screening program for activity to inhibit Wnt signaling

Naomi Mori, Kazufumi Toume, Midori A. Arai, Takashi Koyano, Thaworn Kowithayakorn, Masami Ishibashi

JOURNAL OF NATURAL MEDICINES （SPRINGER TOKYO）  65 （ 1 ） 234 - 236 2011年01月

査読有り,  ISSN  1340-3443

　概要を見る

A screening study using a luciferase assay to identify natural products which inhibit Wnt signaling was carried out. The bioassay-guided fractionation of aerial parts of a plant, Impatiens balsamina, led to the isolation of 2-methoxy-1,4-naphthoquinone (1) as an active compound. Compound 1 inhibited the TCF/beta-catenin (TOP) transcriptional activity (IC(50) 2.9 A mu M), while it decreased the transcriptional activity of FOP (mutated TCF-binding site)-transfected cells at > 5 A mu M.

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New Hedgehog/GLI signaling inhibitors from Excoecaria agallocha

Yusnita Rifai, Midori A. Arai, Samir K. Sadhu, Firoj Ahmed, Masami Ishibashi

BIOORGANIC & MEDICINAL CHEMISTRY LETTERS （PERGAMON-ELSEVIER SCIENCE LTD）  21 （ 2 ） 718 - 722 2011年01月

査読有り,  ISSN  0960-894X

　概要を見る

The inhibition of the Hedgehog (Hh) signaling pathway has emerged as an anti-cancer strategy. Three flavonoid glycosides including 2 new compounds (1-2) were isolated from Excoecaria agallocha as Hedgehog/GLI1-mediated transcriptional inhibitors and exhibited cytotoxicity against human pancreatic (PANC1) and prostate (DU145) cancer cells. Our data revealed that compound 1 clearly inhibited the expression of GLI-related proteins (PTCH and BCL-2) and blocked the translocation of GLI1 transcription factors into the nucleus in PANC1. Deleting the Smoothened (Smo) function in PANC1 treated with 1 led to downregulation of the mRNA expression of Ptch. This study describes the first Hh signaling inhibitor which blocks GLI1 movement into the nucleus without interfering with Smo. (C) 2010 Elsevier Ltd. All rights reserved.

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New hedgehog/GLI-signaling inhibitors from Adenium obesum

Midori A. Arai, Chikashi Tateno, Takashi Koyano, Thaworn Kowithayakorn, Seiichiro Kawabe, Masami Ishibashi

ORGANIC & BIOMOLECULAR CHEMISTRY （ROYAL SOC CHEMISTRY）  9 （ 4 ） 1133 - 1139 2011年

査読有り,  ISSN  1477-0520

　概要を見る

The aberrant hedgehog (Hh)/GLI signaling pathway causes the formation and progression of a variety of tumors. We recently constructed a cell-based screening system to search for Hh/GLI signaling inhibitors from natural resources. Using our screening system, Adenium obesum was found to include Hh/GLI signaling inhibitors from our tropical plant extract libraries. Bioassay-guided fractionation of this plant extract led to the isolation of 17 cardiac glycosides (1-17), including 3 new compounds (4, 9, 16). These compounds showed strong inhibitory activities, especially the IC(50) of 17 is 0.11 mu M. The inhibition of GLI-related protein expression with 3, 9, 11, 15 and 17 was observed in human pancreatic cancer cells (PANC1), which express Hh/GLI components aberrantly. The expressions of GLI-related proteins PTCH and BCL2 were clearly inhibited. These compounds also showed selective cytotoxicity against two cancer cell lines, with less effect against normal cells (C3H10T1/2). RT-PCT examinations showed that Ptch mRNA expression by 3, 11, 15 and 17 was inhibited.

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COMPOUND ANALYSIS VIA GRAPH KERNELS INCORPORATING CHIRALITY

J. B. Brown, Takashi Urata, Takeyuki Tamura, Midori A. Arai, Takeo Kawabata, Tatsuya Akutsu

JOURNAL OF BIOINFORMATICS AND COMPUTATIONAL BIOLOGY （IMPERIAL COLLEGE PRESS）  8   63 - 81 2010年12月

査読有り,  ISSN  0219-7200

　概要を見る

High accuracy is paramount when predicting biochemical characteristics using Quantitative Structural-Property Relationships (QSPRs). Although existing graph-theoretic kernel methods combined with machine learning techniques are efficient for QSPR model construction, they cannot distinguish topologically identical chiral compounds which often exhibit different biological characteristics. In this paper, we propose a new method that extends the recently developed tree pattern graph kernel to accommodate stereoisomers. We show that Support Vector Regression (SVR) with a chiral graph kernel is useful for target property prediction by demonstrating its application to a set of human vitamin D receptor ligands currently under consideration for their potential anti-cancer effects.

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STUDIES ON THE SYNTHESIS AND METABOLISM OF 14-epi-2 alpha-(3-HYDROXYPROPYL)-19-NORVITAMIN D-3 AND ITS 2 beta-ISOMER

Atsushi Kittaka, Hideki Hara, Kaori Yasuda, Masashi Takano, Midori A. Arai, Daisuke Sawada, Hiroshi Saito, Kazuya Takenouchi, Tai C. Chen, Toshiyuki Sakaki

HETEROCYCLES （PERGAMON-ELSEVIER SCIENCE LTD）  82 （ 1 ） 649 - 661 2010年12月

査読有り,  ISSN  0385-5414

　概要を見る

Two derivatives of 14-epi-1 alpha,25-Dihydroxy-19-norvitamin D-3, 14-epi-2 alpha-(3-hydroxypropyl)-1 alpha,25-dihydroxy-19-norvitamin D-3 (14-epi-MART-10) and its 2-epimeric analog (14-epi-MART-11), were synthesized using Julia coupling reaction to connect between the C5 position (steroidal numbering) of an A-ring precursor ketone derived from (-)-quinic acid and the C6 position of a protected 14-epi-CD-ring benzothiazole sulfone. The coupling and deprotection reactions generated a mixture of 14-epi-MART-10 and 14-epi-MART-11 in a moderate yield. The C2-isomers were then separated as their pivalate forms. The C2-stereochemistry of 2 alpha- and 2 beta-isomers was determined by H-1 NMR studies including NOE experiments. The pivaloyl group was removed under basic conditions to obtain the target molecules of 14-epi-MART-10 and 14-epi-MART-11. The metabolism of these two new analogs was further studied in a reconstituted cell-free human CYP24A1 system to elucidate the potential mechanism of their super agonistic action on vitamin D receptor. Our results indicate that epimerization at C14 makes the analogs less susceptible to CYP24A1 degradation and therefore more bio-available, leading to enhanced biological activities.

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Constituents of Pongamia pinnata Isolated in a Screening for Activity to Overcome Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand-Resistance

Tomohiro Minakawa, Kazufumi Toume, Firoj Ahmed, Samir Kumar Sadhu, Takashi Ohtsuki, Midori A. Arai, Masami Ishibasha

CHEMICAL & PHARMACEUTICAL BULLETIN （PHARMACEUTICAL SOC JAPAN）  58 （ 11 ） 1549 - 1551 2010年11月

査読有り,  ISSN  0009-2363

　概要を見る

In a search for natural products with activity to overcome tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-resistance, we performed the bioassay-guided fractionation of a semi mangrove, Pongamia pinnata, collected from Bangladesh, and isolated a new compound, (2S)-(2 '',3 '':7,8)-furanoflavanone (1), along with six known flavonoids (2-7). Two of the compounds significantly overcame TRAIL-resistance in human gastric adenocarcinoma (AGS) cell lines.

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A Bisindole Alkaloid with Hedgehog Signal Inhibitory Activity from the Myxomycete Perichaena chrysosperma

Akinori Shintani, Kazufumi Toume, Yusnita Rifai, Midori A. Arai, Masami Ishibashi

JOURNAL OF NATURAL PRODUCTS （AMER CHEMICAL SOC）  73 （ 10 ） 1711 - 1713 2010年10月

査読有り,  ISSN  0163-3864

　概要を見る

6-Hydroxy-9'-methoxystaurosporinone (1), a new bisindole alkaloid, was isolated from field-collected fruiting bodies of the myxomycete Perichaena chrysosperma, together with two known compounds. The structure of the new alkaloid was elucidated from spectral data, and compound 1 was shown to have hedgehog signal inhibitory activity. A related new alkaloid, 6,9'-dihydroxystaurosporinone (4), was also isolated from Arcyria cinerea.

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Practical Total Synthesis of Fuligocandins A and B

Midori A. Arai, Junya Seto, Firoj Ahmed, Kento Uchiyama, Masami Ishibashi

SYNLETT （GEORG THIEME VERLAG KG）   （ 16 ） 2498 - 2502 2010年10月

査読有り,  ISSN  0936-5214

　概要を見る

Fuligocandins A and B, cycloanthranilylproline derivatives isolated from the myxomycete Fuligo candida, were synthesized efficiently by a Meyer-Schuster rearrangement, which gave Z-isomer with high selectivity. The absolute stereochemistry at C-11a of the natural products was determined to be S by comparison of the optical rotation of the natural products with synthetic counterparts derived from L-proline. This report is the first total synthesis of optically active fuligocandin B.

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Synthesis of vitamin D analogs as ligands for mutant human vitamin D receptor (Arg274Leu)

Shinobu Honzawa, Naoyuki Takahashi, Atsushi Yamashita, Takayuki Sugiura, Midori A. Arai, Shigeaki Kato, Masaaki Kurihara, Atsushi Kittaka

ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY （AMER CHEMICAL SOC）  240 2010年08月

査読有り,  ISSN  0065-7727

Terpenoids and a Flavonoid Glycoside from Acacia pennata Leaves as Hedgehog/GLI-Mediated Transcriptional Inhibitors

Yusnita Rifai, Midori A. Arai, Takashi Koyano, Thaworn Kowithayakorn, Masami Ishibashi

JOURNAL OF NATURAL PRODUCTS （AMER CHEMICAL SOC）  73 （ 5 ） 995 - 997 2010年05月

査読有り,  ISSN  0163-3864

　概要を見る

Overexpression of glioma-associated oncogene 1 (GLI1), which has been characterized as a terminal effector and a target gene of the Hedgehog (Hh) signaling pathway, is associated with the development of cancer. A cellular screen was applied utilizing of a GLI-dependent luciferase reporter in human keratinocyte cells (HaCaT) and identified two terpenoids (1 and 2) and a flavonoid glycoside (5) from Acacia pennata as Hh/GLI inhibitors. Compounds 1, 2, and 5 exhibited selective cytotoxicity against human pancreatic (PANC1) and prostate (DU145) cancer cells with no toxic effect on normal cells. This result was consistent with a dose-dependent reduction of the protein levels of antiapoptotic BCL-2 and the tumor suppressor patched 1 protein (PTCH). Additionally, treatment of 1 downregulated mRNA expression of Ptch in PANC1, suggesting that the compound has an inhibitory effect on the transcription of Hh/GLI.

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Constituents of Amoora cucullata with TRAIL resistance-overcoming activity

Firoj Ahmed, Kazufumi Toume, Samir K. Sadhu, Takashi Ohtsuki, Midori A. Arai, Masami Ishibashi

ORGANIC & BIOMOLECULAR CHEMISTRY （ROYAL SOC CHEMISTRY）  8 （ 16 ） 3696 - 3703 2010年

査読有り,  ISSN  1477-0520

　概要を見る

In search of bioactive natural products for overcoming TRAIL resistance from natural resources, we previously reported a number of active compounds. Bioassay-guided fractionation of mangrove, Amoora cucullata, collected from Sundarbans Mangrove Forest, Bangladesh, led to the isolation of four new compounds (1-4), along with seven known compounds (5-11). Of the isolates, compounds 1, 5, 8, and 9 showed TRAIL resistance-overcoming activity, among which 8 showed the most potent activity and enhanced TRAIL-induced apoptosis in TRAIL-resistant human gastric adenocarcinoma (AGS) cells through the activation of caspase-3/7, enhancing the expression of DR4 and DR5 mRNA in AGS cells. Cell death caused by the combined treatment of 8 and TRAIL was inhibited by human recombinant DR5/Fc and DR4/Fc chimera proteins, indicating that 8 sensitizes TRAIL-resistant AGS cells to TRAIL through the induction of DR4 and DR5.

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Total synthesis and evaluation of Wnt signal inhibition of melleumin A and B, and their derivatives

Midori A. Arai, Shuwa Hanazawa, Yujiro Uchino, Xiaofan Li, Masami Ishibashi

ORGANIC & BIOMOLECULAR CHEMISTRY （ROYAL SOC CHEMISTRY）  8 （ 23 ） 5285 - 5293 2010年

査読有り,  ISSN  1477-0520

　概要を見る

The total synthesis of melleumin A (1), a novel cyclic depsipeptide isolated from the myxomycete Physarum melleum, and 3-epi-melleumin A (6) was achieved. Melleumin A-like compounds were also designed and synthesized; analysis of these melleumin A-like compounds showed moderate Wnt signal inhibition. Comparison of the inhibition activity of melleumin B and its three epimers, melleumin A, 3-epi-melleumin A and three melleumin A-like compounds led to further investigation of the structural conformation of the active molecules. The scaffold of melleumin is a potential target in the search for "peptide-like" Wnt signaling inhibitors.

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Search for Bioactive Natural Products Targeting Cancer-Related Signaling Pathways

Masami Ishibashi, Midori A. Arai

JOURNAL OF SYNTHETIC ORGANIC CHEMISTRY JAPAN （SOC SYNTHETIC ORGANIC CHEM JPN）  67 （ 11 ） 1094 - 1104 2009年11月

査読有り,  ISSN  0037-9980

　概要を見る

During our studies related to the search for bioactive natural products, we recently examined extracts of various natural resources including unexplored myxomycetes, marine organisms, as well as several medicinal plants collected in the north-eastern part of Thailand and Bangladesh. Here we describe our recent results from our screening programs targeting signaling molecules in cancer-related biological pathways such as TRAIL, Writ, and Hedgehog signalings.

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The first Hes1 dimer inhibitors from natural products

Midori A. Arai, Ayako Masada, Toshiyuki Ohtsuka, Ryoichiro Kageyama, Masami Ishibashi

BIOORGANIC & MEDICINAL CHEMISTRY LETTERS （PERGAMON-ELSEVIER SCIENCE LTD）  19 （ 19 ） 5778 - 5781 2009年10月

査読有り,  ISSN  0960-894X

　概要を見る

In the present study, we developed a high-throughput screening system for small molecule-inhibitors of the basic helix-loop-helix (bHLH) transcriptional repressor factor Hes1. Successful dimerization of Hes1 immobilized on a microplate and fluorophore (Cy3)-labelled Hes1 was confirmed. Using this system, several natural products were identified as the first Hes1 dimer inhibitors. Of these, two compounds which were isolated from myxomycetes (true slime molds) inhibited Hes1 from N box-dependent suppression of the gene expression in C3H10T1/2 cells. (C) 2009 Published by Elsevier Ltd.

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Synthesis and Biological Activities of 14-epi-MART-10 and 14-epi-MART-11: Implications for Cancer and Osteoporosis Treatment

Atsushi Kittaka, Hideki Hara, Masashi Takano, Daisuke Sawada, Midori A. Arai, Kenichiro Takagi, Takayuki Chida, Yoshifumi Harada, Hiroshi Saito, Kazuya Takenouchi, Seiichi Ishizuka, Keiko Hayashi, Shinichi Ikushiro, Toshiyuki Sakaki, Takayuki Sugiura, Tai C. Chen

ANTICANCER RESEARCH （INT INST ANTICANCER RESEARCH）  29 （ 9 ） 3563 - 3569 2009年09月

査読有り,  ISSN  0250-7005

　概要を見る

The 14-epimer of MART-10, namely 14-epi-MART-10 (14-epi-2 alpha-(3-hydroxypropyl)-1 alpha,25-dihydroxy-19-norvitamin D(3)) and its 2-epimeric analog (14-epi-MART-11) were efficiently synthesized using the Julia coupling reaction to connect between the C5 and C6 positions (steroid numbering). An A-ring precursor was prepared from (-)-quinic acid as shown in the previous MART-10 synthesis. The novel 14-epi-CD-ring coupling partner with an elongated two carbon unit as a sulfone was synthesized from 14-epi-25-hydroxy Grundmann's ketone in good yield. The subsequent coupling reaction followed by a deprotection step afforded a mixture of 14-epi-MART-10 and 14-epi-MART-11 in 40% yield. To separate 14-epi-MART-10 and 14-epi-MART-11, each primary hydroxyl group was esterified with a pivaloyl group and the resulting pivalates 2 alpha and 2 beta were separated by high performance liquid chromatography. After the separation, the C2-stereochemistry of each (2 alpha or 2 beta) was determined by (1)H NMR (nuclear magnetic resonance) studies including NOE (nuclear Overhauser effect) experiments. The pivaloyl group was removed under basic conditions to obtain the target molecules of 14-epi-MART-10 and 14-epi-MART-11, respectively. The VDR (vitamin D receptor)-binding affinity, HL-60 (human promyelocytic leukemia) cell differentiation activity, antiproliferative activity in PZ-HPV-7 (immortalized normal prostate) cells and transactivation activity of the osteocalcin promoter in HOS (human osteoblast cell line) cells (serum-free conditions) were investigated. In addition, the effects on bone mineral density (BMD) and the blood and urine calcium concentrations of ovariectomized (OVX) rats were examined. 14-epi-MART-10 has much greater antiproliferative and cell differentiation activities compared to 1 alpha,25-dihydroxyvitamin D(3) (1 alpha,25(OH)(2)D(3)).

Synthesis of a 1 alpha-C-methyl analogue of 25-hydroxyvitamin D-3: interaction with a mutant vitamin D receptor Arg274Leu

Shinobu Honzawa, Naoyuki Takahashi, Atsushi Yamashita, Takayuki Sugiura, Masaaki Kurihara, Midori A. Arai, Shigeaki Kato, Atsushi Kittaka

TETRAHEDRON （PERGAMON-ELSEVIER SCIENCE LTD）  65 （ 34 ） 7135 - 7145 2009年08月

査読有り,  ISSN  0040-4020

　概要を見る

Vitamin D-3 analogues have been developed for a mutant vitamin D receptor (VDR), Arg274Leu. The mutant VDR has a Mutation at Arg274, which forms an important hydrogen bond with 1 alpha-OH of 1 alpha,25-dihydroxyvitamin D3 to anchor the ligand tightly in the VDR ligand binding pocket. Stereoselective synthesis of the A-ring part of the novel vitamin D analogue, 2 alpha-(3-hydroxypropyl)-1 alpha-methyl-25-hydroxyvitamin D3 (4), from D-galactose was accomplished with the key steps of the introduction of the methyl and allyl groups to the chiral building blocks. The new analogue 4 is ca. 7.3-fold more active than the natural hormone 1 alpha,25-dihydroxyvitamin D-3 (1). (C) 2009 Elsevier Ltd. All rights reserved,

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