Temko Corporation

Nakano-ku, Japan

Temko Corporation

Nakano-ku, Japan

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Arai M.A.,Chiba University | Tateno C.,Chiba University | Koyano T.,Temko Corporation | Kowithayakorn T.,Khon Kaen University | And 2 more authors.
Organic and Biomolecular Chemistry | Year: 2011

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 IC50 of 17 is 0.11 μM. 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. © 2011 The Royal Society of Chemistry.


Arai M.A.,Chiba University | Koryudzu K.,Chiba University | Koyano T.,Temko Corporation | Kowithayakorn T.,Khon Kaen University | Ishibashi M.,Chiba University
Molecular BioSystems | Year: 2013

Neurogenin2 (Ngn2), an activator-type bHLH transcriptional factor, promotes differentiation of neural stem cells into neurons by transcription of pro-neural genes. To find neural stem cell accelerators from the extract library of natural resources, we used a two-step screening including a Ngn2 promoter reporter gene screening and differentiation assay screening of neural stem cells. A reporter gene assay that can detect Ngn2 promoter activity by luciferase expression was constructed using C3H10T1/2 cells. Using this primary cell-based screening, Butea superba was found to include Ngn2 promoter activators from our tropical plant extract libraries. Bioassay-guided fractionation of this plant extract led to the isolation of 18 natural products, including pterocarpans and isoflavonoids. Dehydromaackiain (1), formononetin (6), (-)-variabilin (13), (-)-medicarpin (14), rothindin (17) and ononin (18) showed 1.8-2.8 times higher Ngn2 promoter activity at 5 μM compared with control. Of active natural compounds, 3′-methoxydaidzein (3) showed promotion of neurite outgrowth of C17.2 in a secondary screen. 3′-Methoxydaidzein (3) increased mRNA expression of pro-neural transcriptional factors (Ngn2, Ngn1, NeuroD2), a mature neuron-specific enzyme GAD1 and a pro-neural neurotrophic growth factor neurotrophin 3 (NT3) in C17.2 neural stem cells. © 2013 The Royal Society of Chemistry.


Rifai Y.,Chiba University | Arai M.A.,Chiba University | Koyano T.,Temko Corporation | Kowithayakorn T.,Khon Kaen University | Ishibashi M.,Chiba University
Journal of Natural Products | Year: 2010

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. © 2010 The American Chemical Society and American Society of Pharmacognosy.


Kikuchi H.,Chiba University | Ohtsuki T.,Chiba University | Koyano T.,Temko Corporation | Kowithayakorn T.,Khon Kaen University | And 2 more authors.
Journal of Natural Products | Year: 2010

A screening study using a luciferase assay to identify natural products that enhance death receptor 5 (DR5) expression was carried out, and bioassay-guided fractionation of two organisms, the pericarp of Garcinia mangostana (mangosteen) and actinomycete CKK609 strain, led to the isolation of eight xanthone derivatives (1- 8) and teleocidin A-2 (9), Among them, compounds 1, 2, and 5, isolated from G. mangostana, and 9, from the actinomycete, showed potent DR5 promoter activity. Furthermore, we revealed that combined treatment with gartanin (5) and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) showed a potentiation effect in sensitizing TRAIL-resistant human gastric adenocarcinoma (AGS) cells. Thus, the present results suggested that 5 has the ability to overcome TRAIL resistance via the up-regulation of DR5 and may be an effective sensitizer of TRAIL-resistant cells. © 2010 American Chemical Society and American Society of Pharmacognosy.


Mori N.,Chiba University | Toume K.,Chiba University | Arai M.A.,Chiba University | Koyano T.,Temko Corporation | And 2 more authors.
Journal of Natural Medicines | Year: 2011

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/β-catenin (TOP) transcriptional activity (IC50 2.9 μM), while it decreased the transcriptional activity of FOP (mutated TCF-binding site)-transfected cells at >5 μM. © 2010 The Japanese Society of Pharmacognosy and Springer.


Toume K.,Chiba University | Nakazawa T.,Chiba University | Ohtsuki T.,Chiba University | Arai M.A.,Chiba University | And 3 more authors.
Journal of Natural Products | Year: 2011

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 DR5 expression, and 16 showed TRAIL-resistance abrogating activity. © 2011 The American Chemical Society and American Society of Pharmacognosy.


Toume K.,Chiba University | Nakazawa T.,Chiba University | Hoque T.,Chiba University | Ohtsuki T.,Chiba University | And 4 more authors.
Planta Medica | Year: 2012

In our screening program for natural products that increase death-receptor 5 expression, seven new cycloartane triterpenes, euphonerins A-G (1-7), and 3-O-acetyl-8-O-tigloylingol (8), a new ingol diterpene, were isolated from the MeOH extract of Euphorbia neriifolia leaves, together with 3,12-di-O-acetyl-8-O- tigloylingol (9), (24R)-cycloartane-3β,24,25-triol (10), and three known flavonols (11-13). The structures of 1-8 were elucidated by spectroscopic analysis. Among these compounds, 1-11 showed death-receptor 5 expression enhancing activity. © Georg Thieme Verlag KG Stuttgart · New York.


Minakawa T.,Chiba University | Toume K.,Chiba University | Arai M.A.,Chiba University | Koyano T.,Temko Corporation | And 2 more authors.
Phytochemistry | Year: 2013

In a screening program for bioactive natural products which can overcome Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)-resistance, three prenylflavonoids, named pannokin A-C, were isolated from a MeOH extract of Artocarpus champeden (Moraceae) roots, together with three known prenylflavonoids. The structures of pannokin A-C were elucidated by spectroscopic analysis. These of the prenylflavonoids in combination with TRAIL, showed cytotoxic activity in sensitizing TRAIL-resistant human gastric adenocarcinoma (AGS) cells. Of these compounds, heterophyllin increased caspase 3/7 activity when combined with TRAIL in AGS cells, and enhanced the expression of DR4 and DR5 mRNA. Moreover, heterophyllin up-regulated mRNA expression of CCAAT/enhancer-binding protein-homologous protein (CHOP) which was reported to be an important regulator of DR5 expression. Thus, heterophyllin was presumed to cause a CHOP-dependent up-regulation of DR5 expression resulting in apoptosis in AGS cells.© 2013 Elsevier Ltd. All rights reserved.


PubMed | Chiba University, Khon Kaen University and Temko Corporation
Type: Journal Article | Journal: Journal of natural products | Year: 2016

A new bis-aporphine alkaloid, cerasoidine (1), was isolated from the root extract of Polyalthia cerasoides together with the known bis-aporphine bidebiline E (2) during screening for compounds with Wnt signal inhibitory activities. The structure of cerasoidine (1) was established by X-ray analysis and shown by chiral HPLC analyses and electronic circular dichroism to be a 57:43 mixture of R(-)- and S(+)-atropisomers. Bidebiline E (2) exhibited inhibition of transcriptional activity of TCF/-catenin with an IC50 value of 20.2 M and was also found to inhibit Wnt signaling by decreasing nuclear -catenin.


PubMed | Chiba University, Khon Kaen University and Temko Corporation
Type: Journal Article | Journal: Journal of natural products | Year: 2016

TRAIL is a potent and selective inducer of apoptosis in most cancer cells while sparing normal cells, which makes it an attractive target for the development of new cancer therapies. In a screening program on natural resources with the ability to abrogate TRAIL resistance, the bioassay-guided fractionation of Boesenbergia pandurata rhizomes resulted in the isolation of 17 pimarane diterpenes and a monoterpene. Among these, compounds 1-8, named boesenberols A-H, are new pimarane diterpenes. All compounds exhibited TRAIL-resistance-overcoming activity in TRAIL-resistant AGS cells. Subtoxic doses of the major compound 9 sensitized AGS cells to TRAIL-induced apoptosis by up-regulating apoptosis-inducing proteins, such as DR4, DR5, p53, Fas, CHOP, Bak, and cleaved caspases-3, -8, and -9, and down-regulating the levels of cell survival proteins, such as Bcl-2, c-FLIP, and GSK-3, in TRAIL-resistant AGS cells. Furthermore, compound 9 did not decrease the viability of noncancerous (HEK293) cells at concentrations up to 30 M.

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