Language：English   Publishing type：Research paper (scientific journal)  

Previously, we reported that the combined use of spermine (SPM) and sodium taurocholate (STC) (SPM-STC) significantly improves the oral absorption of rebamipide (BCS class IV) and pulmonary absorption of interferon-α without any harmful histopathological changes in the gastrointestinal tract and lungs, respectively. In the present study, we examined the effect of SPM-STC on the transport of fluorescein isothiocyanate-labeled dextrans (FDs) across Caco-2 cell monolayers and attempted to clarify the mechanisms underlying the transport enhancement caused by SPM-STC. SPM-STC were found to significantly enhance the transport of FDs, while the treatment with SPM-STC was not harmful, and the decrease in transepithelial electrical resistance was transient and reversible. The voltage-clamp study clearly indicated that the opening of the paracellular route could be mainly responsible for the enhanced transport of FD-4. As for the mechanisms, it was found that SPM-STC caused a significant increase in membrane fluidity, which would lead to the enhanced transport of small-molecule drugs such as rebamipide. Since SPM-STC increased intracellular Ca2+ via Ca2+ uptake through Ca2+ channels and Ca2+ release from the endoplasmic reticulum stimulated by the IP3 pathway, the subsequent possible activation of the MLCK signaling pathway would have led to the contraction of the actin-myosin ring. The rearrangement of tight junction-constituting proteins induced through the MAPK pathway has also been suggested as a possible mechanism for opening tight junctions. Claudin-4, a key protein constituting the tight junction, merged with F-actin along with the plasma membrane, was significantly decreased, which would be at least partial structural evidence for the tight-junction opening.

DOI： 10.1016/j.ejpb.2022.10.020

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Bexarotene, a retinoid X receptor (RXR) agonist, is used to treat cutaneous T-cell lymphoma, and drug repositioning research has also been reported, despite warnings of teratogenicity. However, fetal transfer of bexarotene and its effect on rat fetal bone formation have not been examined. In this study, we conducted a detailed teratogenicity and fetal transferability assessment of bexarotene in rats. Repeated administration of bexarotene during pregnancy caused marked fetal atrophy and bone dysplasia. Although fetal transfer was not detectable by dynamic imaging of [11C]bexarotene by means of positron emission tomography, transfer to the fetus was confirmed by using a gamma counter. Similar levels were found in mother and fetus. In addition, we found that bexarotene was accumulated in the placenta. These findings will be useful for the toxicity assessment of bexarotene as well as for drug discovery research targeting RXR agonists, which are expected to have therapeutic effects in various diseases.

DOI： 10.1021/acsptsci.2c00126

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Vitamin-D receptor (VDR) mRNA is overexpressed in neuroblastoma and carcinomas of lung, pancreas, and ovaries and predicts poor prognoses. VDR antagonists may be able to inhibit tumors that overexpress VDR. However, the current antagonists are arduous to synthesize and are only partial antagonists, limiting their use. Here, we show that the VDR antagonist MeTC7 (5), which can be synthesized from 7-dehydrocholesterol (6) in two steps, inhibits VDR selectively, suppresses the viability of cancer cell-lines, and reduces the growth of the spontaneous transgenic TH-MYCN neuroblastoma and xenografts in vivo. The VDR selectivity of 5 against RXRα and PPAR-γ was confirmed, and docking studies using VDR-LBD indicated that 5 induces major changes in the binding motifs, which potentially result in VDR antagonistic effects. These data highlight the therapeutic benefits of targeting VDR for the treatment of malignancies and demonstrate the creation of selective VDR antagonists that are easy to synthesize.

DOI： 10.1021/acs.jmedchem.1c01878

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Authorship：Last author,　Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acsmedchemlett.1c00575

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Frontiers Media SA  

Retinoid X receptor (RXR) is a nuclear receptor that heterodimerizes with several nuclear receptors, integrating ligand-mediated signals across the heterodimers. Synthetic RXR agonists have been developed to cure certain inflammatory diseases, including inflammatory bowel diseases (IBDs). However, pre-existing RXR agonists, which are lipophilic and readily absorbed in the upper intestine, cause considerable adverse effects such as hepatomegaly, hyperlipidemia, and hypothyroidism. To minimize these adverse effects, we have developed an RXR agonist, NEt-3IB, which has lipophilic and thus poorly absorptive properties. In this study, we evaluated the effects of NEt-3IB in an experimental murine colitis model induced through the adoptive transfer of CD45RB^highCD4⁺ T cells. Pharmacokinetic studies demonstrated that the major portion of NEt-3IB was successfully delivered to the large intestine after oral administration. Notably, NEt-3IB treatment suppressed the development of T cell-mediated chronic colitis, as indicated by improvement of wasting symptoms, inflammatory infiltration, and mucosal hyperplasia. The protective effect of NEt-3IB was mediated by the suppression of IFN-γ-producing Th1 cell expansion in the colon. In conclusion, NEt-3IB, a large intestine-directed RXR agonist, is a promising drug candidate for IBDs.

DOI： 10.3389/fphar.2021.715752

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Authorship：Last author,　Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society ({ACS})  

DOI： 10.1021/acsmedchemlett.1c00201

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society ({ACS})  

DOI： 10.1021/acs.jmedchem.0c01714

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Authorship：Last author,　Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society ({ACS})  

DOI： 10.1021/acs.jmedchem.0c01354

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Authorship：Last author,　Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

DOI： 10.1016/j.bmcl.2020.127666

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Retinoid X receptor (RXR) is a nuclear receptor that heterodimerizes with several nuclear receptors, integrating ligand-mediated signals across the heterodimers. Synthetic RXR agonists have been developed to cure certain inflammatory diseases, including inflammatory bowel diseases (IBDs). However, pre-existing RXR agonists, which are lipophilic and readily absorbed in the upper intestine, cause considerable adverse effects such as hepatomegaly, hyperlipidemia, and hypothyroidism. To minimize these adverse effects, we have developed an RXR agonist, NEt-3IB, which has lipophilic and thus poorly absorptive properties. In this study, we evaluated the effects of NEt-3IB in an experimental murine colitis model induced through the adoptive transfer of CD45RBhighCD4+ T cells. Pharmacokinetic studies demonstrated that the major portion of NEt-3IB was successfully delivered to the large intestine after oral administration. Notably, NEt-3IB treatment suppressed the development of T cell-mediated chronic colitis, as indicated by improvement of wasting symptoms, inflammatory infiltration, and mucosal hyperplasia. The protective effect of NEt-3IB was mediated by the suppression of IFN-γ-producing Th1 cell expansion in the colon. In conclusion, NEt-3IB, a large intestine-directed RXR agonist, is a promising drug candidate for IBDs.

DOI： 10.3389/fphar.2021.715752

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Authorship：Last author,　Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

Retinoid X receptor (RXR) modulators (rexinoids) are considered to have therapeutic potential for multiple diseases, such as Alzheimer's disease and Parkinson's disease. To overcome various disadvantages of prior screening methods, we previously developed an RXR binding assay using a fluorescent RXR ligand, CU-6PMN (4). However, this ligand binds not only at the ligand-binding domain (LBD) but also at the dimer-dimer interface of hRXRα. Here, we present a new fluorescent RXR antagonist 6-[N-ethyl-N-(5-isobutoxy-4-isopropyl-2-(11-oxo-2,3,6,7-tetrahydro-1H,5H,11H-pyrano[2,3-f]pyrido[3,2,1-ij]quinoline-10-carboxamido)phenyl)amino]nicotinic acid (NEt-C343, 7), which emits strong fluorescence only when bound to the RXR-LBD. It allows us to perform a rapid, simple, and nonhazardous binding assay that does not require bound/free separation and uses a standard plate reader. The obtained Ki values of known compounds were correlated with the Ki values obtained using the standard [³H]9cis-retinoic acid assay. This assay should be useful for drug discovery as well as for research on endocrine disruptors, functional foods, and natural products.

DOI： 10.1021/acs.jmedchem.0c01883

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：{MDPI} {AG}  

"Combination therapy", which is a treatment modality combining two or more therapeutic agents, is considered a cornerstone of cancer therapy. The combination of anticancer drugs, of which functions are different from the other, enhances the efficiency compared to the monotherapy because it targets cancer cells in a synergistic or an additive manner. In this study, the combination of paclitaxel and sorafenib in low concentration was evaluated to target cancer stem cells, miPS-BT549cmP and miPS-Huh7cmP cells, developed from mouse induced pluripotent stem cells. The synergistic effect of paclitaxel and sorafenib on cancer stem cells was assessed by the inhibition of proliferation, self-renewal, colony formation, and differentiation. While the IC50 values of paclitaxel and sorafenib were approximately ranging between 250 and 300 nM and between 6.5 and 8 µM, respectively, IC50 of paclitaxel reduced to 20 and 25 nM, which was not toxic in a single dose, in the presence of 1 µM sorafenib, which was not toxic to the cells. Then, the synergistic effect was further assessed for the potential of self-renewal of cancer stem cells by sphere formation ability. As a result, 1 µM of sorafenib significantly enhanced the effect of paclitaxel to suppress the number of spheres. Simultaneously, paclitaxel ranging in 1 to 4 nM significantly suppressed not only the colony formation but also the tube formation of the cancer stem cells in the presence of 1 µM sorafenib. These results suggest the combination therapy of paclitaxel and sorafenib in low doses should be an attractive approach to target cancer stem cells with fewer side effects.

DOI： 10.3390/cancers12061360

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<jats:p>Antibiotics and dietary habits can affect the gut microbial community, thus influencing disease susceptibility. Although the effect of microbiota on the postnatal environment has been well documented, much less is known regarding the impact of gut microbiota at the embryonic stage. Here we show that maternal microbiota shapes the metabolic system of offspring in mice. During pregnancy, short-chain fatty acids produced by the maternal microbiota dictate the differentiation of neural, intestinal, and pancreatic cells through embryonic GPR41 and GPR43. This developmental process helps maintain postnatal energy homeostasis, as evidenced by the fact that offspring from germ-free mothers are highly susceptible to metabolic syndrome, even when reared under conventional conditions. Thus, our findings elaborate on a link between the maternal gut environment and the developmental origin of metabolic syndrome.</jats:p>

DOI： 10.1126/science.aaw8429

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media {LLC}  

Chronic hepatitis viral infection, alcoholic intoxication, and obesity cause liver fibrosis, which progresses to decompensated liver cirrhosis, a disease for which medical demands cannot be met. Since there are currently no approved anti-fibrotic therapies for established liver fibrosis, the development of novel modalities is required to improve patient prognosis. In this study, we clarified the anti-fibrotic effects of cell sheets produced from human bone marrow-derived mesenchymal stem cells (MSCs) incubated on a temperature-sensitive culture dish with the chemical compound IC-2. Orthotopic transplantation of IC-2-engineered MSC sheets (IC-2 sheets) remarkably reduced liver fibrosis induced by chronic CCl4 administration. Further, the marked production of fibrolytic enzymes such as matrix metalloproteinase (MMP)-1 and MMP-14, as well as thioredoxin, which suppresses hepatic stellate cell activation, was observed in IC-2 sheets. Moreover, the anti-fibrotic effect of IC-2 sheets was much better than that of MSC sheets. Finally, knockdown experiments revealed that MMP-14 was primarily responsible for the reduction of liver fibrosis. Here, we show that IC-2 sheets could be a promising therapeutic option for established liver fibrosis.

DOI： 10.1038/s41598-019-43298-0

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Ligands for retinoid X receptors (RXRs), "rexinoids", are attracting interest as candidates for therapy of type 2 diabetes and Alzheimer's and Parkinson's diseases. However, current screening methods for rexinoids are slow and require special apparatus or facilities. Here, we created 7-hydroxy-2-oxo-6-(3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydronaphthalen-2-yl)-2H-chromene-3-carboxylic acid (10, CU-6PMN) as a new fluorescent RXR agonist and developed a screening system of rexinoids using 10. Compound 10 was designed based on the fact that umbelliferone emits strong fluorescence in a hydrophilic environment, but the fluorescence intensity decreases in hydrophobic environments such as the interior of proteins. The developed assay using 10 enabled screening of rexinoids to be performed easily within a few hours by monitoring changes of fluorescence intensity with widely available fluorescence microplate readers, without the need for processes such as filtration.

DOI： 10.1021/acs.jmedchem.9b00995

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

Several retinoid X receptor (RXR) ligands (rexinoids), such as bexarotene (1), exhibit teratogenicity, which is a serious impediment to their clinical application. We considered that rexinoids with a lower level of maximal RXR transcription activation (i.e., partial agonists) and lower lipid solubility might show weaker adverse side effects. Based on this idea, we modified our previously reported pentamethyltetralin-type RXR partial agonists 5 and 6 to reduce their lipophilicity. Here, we report a new RXR partial agonist, 3-(3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydronaphthalen-2-yl)-2-(trifluoromethyl)-3H-imidazo[4,5-b]pyridine-6-carboxylic acid (8, CATF-PMN), which showed greatly reduced teratogenicity in zebrafish embryos.

DOI： 10.1016/j.bmcl.2019.05.050

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Authorship：Last author,　Corresponding author   Language：English   Publisher：AMER CHEMICAL SOC  

DOI： 10.1021/acs.jmedchem.9b00617

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Bexarotene (1), a retinoid X receptor (RXR) agonist approved for the treatment of cutaneous T cell lymphoma (CTCL), was reported to migrate into baboon brain based on findings obtained by positron emission tomography (PET) with a 11C-labeled tracer. However, co-administration of non-radioactive 1 had no effect on the distribution of [11C]1, probably due to non-specific binding of 1 as a result of its high lipophilicity. Here, we report a fluorine-18 (18F)-labeled PET tracer [18F]6 derived from RXR partial agonist CBt-PMN (2), which has lower lipophilicity and weaker RXR-binding ability than [11C]1. The concomitant administration of 1 or 2 with [18F]6 with resulted in decreased accumulation of [18F]6 in liver, together with increased brain uptake and increased accumulation in kidney and muscle, as visualized by PET. A plausible explanation of these findings is the inhibition of [18F]6 uptake into the liver by concomitantly administered 1 or 2, leading to an increase in blood concentration of [18F]6 followed by increased accumulation in other tissues.

DOI： 10.1016/j.bmc.2019.05.045

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Language：English   Publishing type：Research paper (scientific journal)  

Inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease, is an intractable disease of the gastrointestinal tract. Multiple environmental factors, including food ingredients, have been implicated in the development of these diseases. For example, animal fat-rich diets are predisposing factors for ulcerative colitis, whereas n-3 unsaturated fatty acids such as docosahexaenoic acid (DHA) show protective effects in experimental colitis and are negatively correlated with the incidence of ulcerative colitis and Crohn's disease. Given that DHA exhibits agonistic activity on retinoid X receptor (RXR), activation of RXR could be a therapeutic strategy for IBD. However, conventional full RXR agonists are known to show considerable adverse effects. We therefore took advantage of a partial RXR agonist, CBt-PMN, to minimize the adverse effects, and evaluated its efficacy in dextran sodium sulfate-induced colitis. Administration of CBt-PMN efficiently ameliorated the symptoms of colitis. This effect was attributed to the down-regulation of pro-inflammatory cytokines such as Tnf and Il6 in colon-infiltrating monocytes. Down-regulation of pro-inflammatory cytokines by CBt-PMN was also evident in lipopolysaccharide-stimulated bone marrow-derived macrophages (BMDMs). Among many RXR-associated nuclear receptors, activation of peroxisome proliferator-activated receptor δ (PPARδ) and nuclear hormone receptor 77 (Nur77) suppressed cytokine production by BMDMs. These observations suggest that the activation of PPARδ/RXR and Nur77/RXR heterodimers by CBt-PMN through the permissive mechanism is responsible for diminishing the monocyte-mediated inflammatory response in the gut. Our data highlight the importance of RXR activation in the regulation of colitis.

DOI： 10.1093/intimm/dxy089

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Language：Japanese   Publisher：(公社)日本整形外科学会  

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BACKGROUND: Retinoid X receptors (RXRs) are members of the nuclear receptor (NR) superfamily that mediate signalling by 9-cis retinoic acid, a vitamin A derivative. RXRs play key roles not only as homodimers but also as heterodimeric partners, e.g., for retinoic acid receptors, vitamin D receptors, and peroxisome proliferator-activated receptors. The NR family may also play important roles in the development of emphysema. However, the role of RXRs in the pathogenesis of emphysema is not well defined. METHODS: We developed a novel RXR partial agonist (NEt-4IB) and investigated its effect and mechanism compared to a full agonist (bexarotene) in a murine model of emphysema. For emphysema induction, BALB/c mice received intraperitoneal cigarette smoke extract (CSE) or intratracheal porcine pancreas elastase (PPE). Treatment with RXR agonists was initiated before or after emphysema induction. RESULTS: Treatment with NEt-4IB significantly suppressed the increase in static lung compliance and emphysematous changes in CSE-induced emphysema and PPE-induced established and progressive emphysema. NEt-4IB significantly suppressed PPE-induced neutrophilic airway inflammation and the levels of keratinocyte chemoattractant (KC), C-X-C motif ligand5 (CXCL5), interferon (IFN)-γ and IL-17. NEt-4IB also improved the matrix metalloproteinase-9 (MMP-9)/tissue inhibitor of metalloproteinase-1 (TIMP-1) imbalance and the reduced anti-oxidant activity in bronchoalveolar lavage (BAL) fluid. NEt-4IB suppressed PPE-induced vascular endothelial growth factor (VEGF) expression in the airway. Treatment with NEt-4IB and bexarotene significantly suppressed the increase in static lung compliance and emphysematous changes. However, adverse effects of RXR agonists, including hypertriglyceridemia and hepatomegaly, were observed in bexarotene-treated mice but not in NEt-4IB-treated mice. CONCLUSION: These data suggest that RXRs play crucial roles in emphysema and airway inflammation, and novel partial RXR agonists could be potential therapeutic strategies for the treatment of PPE- and CSE-induced emphysema.

DOI： 10.1186/s12931-018-0963-0

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

1-[(3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydronaphthalen-2-yl)amino]benzotriazole-5-carboxylic acid (CBt-PMN), a partial agonist of retinoid X receptor (RXR), has attracted attention due to its potential to treat type 2 diabetes and central nervous system diseases with reduced adverse effects of existing full agonists. Herein, we report the crystal structure of CBt-PMN-bound ligand-binding domain of human RXRα (hRXRα) and its biochemical characterization. Interestingly, the structure is a tetramer in nature, in which CBt-PMNs are clearly found binding in two different conformations. The dynamics of the hRXRα/CBt-PMN complex examined using molecular dynamics simulations suggest that the flexibility of the AF-2 interface depends on the conformation of the ligand. These facts reveal that the dual conformation of CBt-PMN in the complex is probably the reason behind its partial agonistic activity.

DOI： 10.1002/1873-3468.13301

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DOI： 10.1248/yakushi.18-00193-3

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DOI： 10.1248/yakushi.18-00193-F

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Publishing type：Research paper (scientific journal)   Publisher：{MDPI} {AG}  

DOI： 10.3390/ijms19082354

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DOI： 10.3390/ijms19082354

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Language：English   Publishing type：Research paper (scientific journal)  

PURPOSE: Testosterone suppression in prostate cancer is limited by serious side effects and resistance via restoration of androgen receptor (AR) functionality. ELK1 is required for AR-dependent growth in various hormone-dependent and castration-resistant prostate cancer models. The amino-terminal domain of AR docks at two sites on ELK1 to coactivate essential growth genes. This study explores the ability of small molecules to disrupt the ELK1-AR interaction in the spectrum of prostate cancer, inhibiting AR activity in a manner that would predict functional tumor selectivity. EXPERIMENTAL DESIGN: Small-molecule drug discovery and extensive biological characterization of a lead compound. RESULTS: We have discovered a lead molecule (KCI807) that selectively disrupts ELK1-dependent promoter activation by wild-type and variant ARs without interfering with ELK1 activation by ERK. KCI807 has an obligatory flavone scaffold and functional hydroxyl groups on C5 and C3'. KCI807 binds to AR, blocking ELK1 binding, and selectively blocks recruitment of AR to chromatin by ELK1. KCI807 primarily affects a subset of AR target growth genes selectively suppressing AR-dependent growth of prostate cancer cell lines with a better inhibitory profile than enzalutamide. KCI807 also inhibits in vivo growth of castration/enzalutamide-resistant cell line-derived and patient-derived tumor xenografts. In the rodent model, KCI807 has a plasma half-life of 6 hours, and maintenance of its antitumor effect is limited by self-induced metabolism at its 3'-hydroxyl. CONCLUSIONS: The results offer a mechanism-based therapeutic paradigm for disrupting the AR growth-promoting axis in the spectrum of prostate tumors while reducing global suppression of testosterone actions. KCI807 offers a good lead molecule for drug development.

DOI： 10.1158/1078-0432.ccr-18-0982

DOI： 10.1158/1078-0432.CCR-18-0982

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DOI： 10.3390/ijms19082354

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DOI： 10.20944/preprints201806.0208.v1

DOI： 10.3390/ijms19082354

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society ({ACS})  

The retinoid X receptor (RXR) partial agonist 1-[(3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydronaphthalen-2-yl)amino]benzotriazole-5-carboxylic acid (1; CBt-PMN, Emax = 75%, EC50 = 143 nM) is a candidate for treatment of central nervous system (CNS) diseases such as Alzheimer's and Parkinson's diseases based on reports that RXR-full agonist 4-[1-(3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydro-2-naphthyl)ethynyl]benzoic acid (bexarotene) shows therapeutic effects on these disease in rodent models. Here, we synthesized carbon-11-labeled ([11C]1) as a tracer for positron emission tomography (PET) and used it in a PET imaging study to examine the brain uptake and biodistribution of 1. We found that 11CO2 fixation after tin-lithium exchange at -20 °C afforded [11C]1. This methodology may also be useful for synthesizing 11CO2H-PET tracer derivatives of other compounds bearing π-rich heterocyclic rings. A PET/CT imaging study of [11C]1 in mice indicated 1 is distributed to the brain and is thus a candidate for treatment of CNS diseases.

DOI： 10.1021/acs.jmedchem.7b00817

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BACKGROUND: Retinoid X receptors (RXRs) are members of the nuclear receptor (NR) superfamily that mediate signaling by 9-cis retinoic acid, a vitamin A (retinol) derivative. RXRs play key roles not only as homodimers but also as heterodimeric partners-e.g., retinoic acid receptors (RARs), vitamin D receptors (VDRs), liver X receptors (LXRs), and peroxisome proliferator-activated receptors (PPARs). The NR family was recently associated with allergic diseases, but the role of RXRs in allergen-induced airway responses is not well defined. The goal of this study is to elucidate the role of RXRs in asthma pathogenesis and the potency of RXR partial agonist in the treatment of allergic airway inflammation and airway hyperresponsiveness using a murine model of asthma. METHODS: We investigated the effect of a novel RXR partial agonist (NEt-4IB) on the development of allergic airway inflammation and airway hyperresponsiveness (AHR) in a murine model of asthma. Balb/c mice were sensitized (days 0 and 14) and challenged (days 28-30) with ovalbumin (OVA), and airway inflammation and airway responses were monitored 48 h after the last OVA challenge. NEt-4IB was administered orally on days 25 to 32. RESULTS: Oral administration of NEt-4IB significantly suppressed AHR and inflammatory cell accumulation in the airways and attenuated the levels of TNF-α in the lung and IL-5, IL-13 and NO levels in bronchoalveolar lavage (BAL) fluid and the number of periodic acid Schiff (PAS)-positive goblet cells in lung tissue. Treatment with NEt-4IB also significantly suppressed NF-κB expression. CONCLUSION: These data suggest that RXRs may be of crucial importance in the mechanism of allergic asthma and that the novel RXR partial agonist NEt-4IB may be a promising candidate for the treatment of allergic airway inflammation and airway hyperresponsiveness in a model of allergic asthma.

DOI： 10.1186/s12931-017-0507-z

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Language：English   Publisher：AMER THORACIC SOC  

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DOI： 10.2174/1568026616666160617085545

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Language：English   Publisher：AMER THORACIC SOC  

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DOI： 10.2174/1568026616666160617085545

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

We previously reported RXR partial agonist CBt-PMN (1-(3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydro-2-naphthyl)-1H-benzotriazole-5-carboxylic acid: &lt;bold&gt;5&lt;/bold&gt;, EC50 = 143 nM, E-max = 75%), which showed a potent glucose-lowering effect without causing serious adverse effects. However, it remains important to elucidate the structural requirements for RXR efficacy and the glucose-lowering effect because RXR-permissive heterodimers such as PPAR/RXR or LXR/RXR are reported to be activated differently depending upon the chemical structure of RXR agonists. In this work, we show that an RXR partial agonist, NEt-4IB (6-[ethyl-(4-isobutoxy-3-isopropylphenyl)amino]pyridine-3-carboxylic acid: &lt;bold&gt;8b&lt;/bold&gt;, EC50 = 169 nM, E-max = 55%), can be obtained simply by repositioning the side chains (interchanging the isobutoxy and isopropoxy groups) at the hydrophobic moiety of the RXR full agonist NEt-3IB (6-[ethyl-(3-isobutoxy-4-isopropylphenyl)amino]pyridine-3-carboxylic acid: &lt;bold&gt;7b&lt;/bold&gt;, EC50 = 19 nM). NEt-4IB (&lt;bold&gt;8b&lt;/bold&gt;) showed antitype 2 diabetes activity without the above side effects upon repeated oral administration to mice at 10 mg/kg/day, similarly to &lt;bold&gt;5&lt;/bold&gt;.

DOI： 10.1021/jm501863r

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

RXR partial agonist NEt-41B (2a, 6-[ethyl-(4-isobutoxy-3-isopropylphenyl)amino]pyridine-3-carboxylic acid: EC50 = 169 nM, E-max = 55%) showed a blood concentration higher than its Emax after single oral administration at 30 mg/kg to mice, and repeated oral administration at 10 mg/kg/day to KK-A(y) mice afforded antitype 2 diabetes activity without the side effects caused by RXR full agonists. However, RXR full agonist NEt-3IB (la), in which the isobutoxy and isopropyl groups of 2a are interchanged, gave a much lower blood concentration than 2a. Here we used positron emission tomography (PET) with tracers [C-11] la, [C-11]2a and fluorinated derivatives [F-18] lb, [F-18]2b, which have longer half-lives, to examine the reason why la and 2a exhibited significantly different blood concentrations. As a result, the reason for the high blood concentration of 2a after oral administration was found to be linked to higher intestinal absorbability together with lower biliary excretion, compared with la.

DOI： 10.1021/ml500511m

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：INFORMA HEALTHCARE  

Objective: The hepatic metabolism of six compounds newly synthesized as retinoid X receptor agonists was characterized in rat and human liver microsomes to examine the relationship between their hepatic metabolism profiles and side chain structures, considering the interspecies difference.
Materials and methods: The compounds used have a 6-[N-ethyl-N-(3-alkoxy-4-isopropylphenyl)amino]nicotinic or 6-[N-ethyl-N-(4-alkoxy-3-isopropylphenyl)amino]nicotinic acid skeleton, in which the isopropoxy, isobutoxy or cyclopropylmethoxy group is employed for the alkoxy group. These compounds were incubated with the microsomes, and their Michaelis-Menten parameters were determined. The incubation study was also performed with various cytochrome P450 (CYP) inhibitors to examine their susceptibilities to the inhibitors. In addition, a molecular docking simulation was conducted to assess the compound's spatial configuration with the CYP isoform when necessary.
Results: The Michaelis-Menten parameters determined are comparable between rats and humans for the compounds having 3-isobutoxy, 4-isobutoxy, 4-isopropoxy and 4-cyclopropylmethoxy groups. However, it was indicated that all compounds except that having the 3-isobutoxy group are metabolized in a different manner between rats and humans. That is, the extent of the contribution of each CYP isozyme is different between those two species. A molecular docking simulation showed that the spatial configuration of the compound to be associated with CYP2D6 markedly changes depending on whether the isobutoxy group is situated at the 3- or 4-position.
Conclusion: A slight difference in the side chain structures markedly alters the compound's metabolic profile, which amplifies the interspecies difference regarding the profile, increasing the difficulty in characterizing the profile in humans with the structural-property relationship and interspecies extrapolation.

DOI： 10.3109/03639045.2013.807278

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Inhibition of angiogenesis is currently perceived as a promising strategy in the treatment of cancer. The anti-angiogenicity of thalidomide has inspired a second wave of research on this teratogenic drug. The present study aimed to investigate the anti-proliferative and anti-angiogenic activities of two thalidomide dithiocarbamate analogs by studying their anti-proliferative effects on human umbilical vein endothelial cells (HUVECs) and MDA-MB-231 human breast cancer cell lines. Their action on the expression levels of IL-6, IL-8, TNF-alpha, VEGF(165), and MMP-2 was also assessed. Furthermore, their effect on angiogenesis was evaluated through wound healing, migration, tube formation, and nitric oxide (NO) assays. Results illustrated that the proliferation of HUVECs and MDA-MB-231 cells was not significantly affected by thalidomide at 625-100 mu M. Thalidomide failed to block angiogenesis at similar concentrations. By contrast, thalidomide dithiocarbamate analogs exhibited significant anti-proliferative action on HUVECs and MDA-MB-231 cells without causing cytotoxicity and also showed powerful anti-angiogenicity in wound healing, migration, tube formation, and NO assays. Thalidomide analogs 1 and 2 demonstrated more potent activity to suppress expression levels of IL-6, IL-8, TNF-alpha, VEGF(165), and MMP-2 than thalidomide. Analog 1 consistently, showed the highest potency and efficacy in all the assays. Taken together, our results support further development and evaluation of novel thalidomide analogs as antitumor and anti-angiogenic agents. (C) 2014 The Authors. Published by Elsevier B.V.

DOI： 10.1016/j.intimp.2014.05.007

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Glucocorticoids are effective anti-inflammatory agents widely used for the treatment of acute and chronic inflammatory diseases. Recent in vitro studies have proposed that glucocorticoid receptor (GR) activation is involved in peroxisome proliferator-activated receptor γ (PPARγ) agonist-induced effects. In this study, to examine the involvement of the GR in PPARγ agonist- and retinoid X receptor (RXR) agonist-mediated anti-inflammatory effects in vivo, we tested the anti-inflammatory effects of dexamethasone (a GR agonist) with pioglitazone (a PPARγ agonist) or 6-[N-ethyl-N-(3-isopropoxy-4-isopropylphenyl)-amino] nicotinic acid (NEt-3IP; an RXR agonist) by using an experimental model of carrageenan-induced inflammation. We also evaluated the effects of a GR antagonist on PPARγ agonist- or RXR agonist-induced anti-inflammatory effects. Results showed that the GR antagonist RU486 reduced the anti-inflammatory effects of GR or PPARγ agonists but not those of the RXR agonist. In addition, combinations of GR and PPARγ agonists or GR and RXR agonists had no effect on carrageenan-induced paw edema. Moreover, the PPARγ antagonist GW9662 and RXR antagonist 6-[N-4-(trifluoromethyl)-benzenesulfonyl-N-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-2-naphthyl)-amino] nicotinic acid (NS-4TF) had no effect on the anti-inflammatory effect of the GR agonist dexamethasone. Therefore, it is suggested that GR activation in vivo does not play a direct role in PPARγ/RXR heterodimer signaling. In contrast, pioglitazone showed a partial anti-inflammatory effect via GR activation. These data provide evidence for the pro-inflammatory activity of pioglitazone.

DOI： 10.1016/j.intimp.2014.06.028

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We have reported that retinoid X receptor (RXR) partial agonist 1-(3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydro-2-naphthyl)-1H-benzotriazole-5-carboxylic acid (CBt-PMN, 4a) shows a significant antidiabetes effect in the KK-A(y) type 2 diabetes model mice, with reduced side effects compared to RXR full agonists. To elucidate the mechanism of the RXR partial agonist activity of 4a, we synthesized derivatives of 4a, evaluated their RXR agonist activity, and performed structure-activity relationship analysis. Reporter gene assay revealed that though 6b, which possesses an amino group at the 2-position of 5-carboxybenzimidazole, showed RXR full-agonist activity, compounds 6d and 6e, which possess an oxygen atom and a sulfur atom at the corresponding position, respectively, showed weak RXR agonist activity. On the other hand, 6c, which has a trifluoromethyl group at the corresponding position, acts as an RXR partial agonist, having similar E-max (67 +/- 2%) and lower EC50 (15 +/- 0 nM) compared to those of 4a (E-max = 75 +/- 4%, EC50 = 143 +/- 2 nM). A fluorescence polarization assay of cofactor recruitment confirmed that fluorescein-labeled D22 coactivator peptide was less efficiently recruited to RXR by 4a and 6c than by LGD1069 (1), a known RXR full agonist. Electrostatic potential field calculations and computational docking studies suggested that full agonists show an electrostatic attraction, which stabilizes the holo structure and favors coactivator recruitment, between the side chain at the benzimidazole 2-position and the a-carbonyl oxygen of asparagine-306 in helix 4 (H4) of the RXR receptor. However, RXR partial agonists 4a and 6c lack this interaction. Like 4a, 6c showed a significant antidiabetes effect in KK-A(y) type 2 diabetes model mice with reduced levels of the side effects associated with RXR full agonists. These findings should aid the design of new RXR partial agonists as antitype 2 diabetes drug candidates.

DOI： 10.1021/jm400033f

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Treating insulin resistance and type 2 diabetes in rodents, currently known retinoid X receptor (RXR) agonists induce significant adverse effects. Here we introduce a novel RXR partial agonist CBt-PMN (11b), which shows a potent glucose-lowering effect and improvements of insulin secretion and glucose tolerance without the serious adverse effects caused by RXR full agonists. We suggest that RXR partial agonists may be a new class of antitype 2 diabetes drug candidates.

DOI： 10.1021/ml300055n

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Nuclear receptors (NRs) have recently received much attention for their newly discovered roles in T cell development, as exemplified by RARα (Treg cells) and RORγt (Th17 cells). In previous studies, we characterized a new type of T cell subset, designated as Tchreg (cytotoxic, helper, and regulatory T) cells, in terms of its cytokine signature. In this study, we investigated the expression and functional relevance of NRs in Tchreg cells by performing mRNA profiling of HOZOT, a cord blood-derived Tchreg cell line. We identified eleven inducible and eight constitutively expressed NRs in HOZOT. Among these NRs, RXRα and PPARγ showed features of signature NRs of Tchreg cells because they were selectively expressed in HOZOT compared with other T cell subsets. These NRs exhibited contrasting expression patterns, as RXRα was independent of anti-CD3/28 antibody stimulation while PPARγ was stimulated-dependent. Upon agonist treatment, both proteins translocated to the nucleus and inhibited IFN-γ production through binding to the promoter region of the IFN-γ gene. These results provide new insight into the roles of RXRα and PPARγ in T cell biology, especially in their biological relevance in Tchreg cells. © 2012 Elsevier B.V.

DOI： 10.1016/j.rinim.2012.08.001

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PHARMACEUTICAL SOC JAPAN  

Retinoid X receptor (RXR) agonists are reported to exhibit blood glucose-lowering action owing to peroxisome proliferator-activated receptor (PPAR)/RXR or liver X receptor (LXR)/RXR activation, but may also cause adverse effects such as blood triglyceride elevation. In order to examine the feasibility of separating the glucose-lowering action from the adverse effects, we examined the effects of RXR agonists (NEt-TMN), NEt-3IB, and NEt-3IP, which have different heterodimer-activating patterns, in KKA(y) type 2 diabetes model mice. We found that NEt-3IB induced lower degrees of hepatomegaly and blood triglyceride (TG) elevation than the other RXR agonists, even though all of them showed similar blood glucose-lowering action on repeated administration. These findings indicate that structural modification of RXR agonists is a potentially effective strategy to reduce adverse effects while retaining desired activities.

DOI： 10.1248/bpb.35.629

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：HINDAWI PUBLISHING CORPORATION  

Peroxisome proliferator-activated receptor gamma (PPAR gamma) forms a heterodimeric DNA-binding complex with retinoid X receptors (RXRs). It has been reported that the effect of the PPAR agonist is reduced in hepatocyte RXR-deficient mice. Therefore, it is suggested that the endogenous RXR ligand is involved in the PPAR gamma agonist-induced anti-inflammatory effect. However, the participation of the RXR ligand in the PPAR gamma-induced anti-inflammatory effect is unknown. Here, we investigated the influence of RXR antagonist on the anti-inflammatory effect of PPAR gamma agonist pioglitazone in carrageenan test. In addition, we also examined the influence of PPAR antagonist on the anti-inflammatory effect induced by RXR agonist NEt-3IP. The RXR antagonist suppressed the antiedema effect of PPAR gamma agonist. In addition, the anti-inflammatory effect of RXR agonist was suppressed by PPAR gamma antagonist. PPAR gamma agonist-induced anti-inflammatory effects were reversed by the RXR antagonist. Thus, we showed that the endogenous RXR ligand might contribute to the PPAR gamma agonist-induced anti-inflammatory effect.

DOI： 10.1155/2011/840194

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Retinal angiogenesis is a leading cause of blindness, including retinopathy of prematurity, diabetic retinopathy, and age-related macular degeneration. Vascular endothelial growth factor (VEGF) is one of the major angiogenesis factors, and induces endothelial cell proliferation and migration. VEGF stimulates NADPH oxidase to produce reactive oxygen species (ROS), and ROS induce the transcription factors and genes involved in angiogenesis. In the present study, we demonstrated that GPU-4, 5-arylidene-2,4-thiazolidinedione derivative, demonstrates anti-angiogenic activity regarding human retinal microvascular endothelial cells (HRMECs) and retinal neovascularization in a mouse model of retinopathy of prematurity. GPU-4 inhibited the VEGF-induced radicals, proliferation, and migration in HRMECs without a PPAR.-mediated effect. Furthermore, systemic administration of GPU-4 inhibited the development of retinal neovascularization in a murine oxygen-induced retinopathy model but did not exert revascularization of the capillary-free area, which shows normal physiological revascularization. These findings indicate that GPU-4 suppressed in vitro and in vivo retinal neovascularization partly by a radical scavenging effect, suggesting that GPU-4 might be a potential therapeutic agent candidate for proliferative diseases of the retinal vasculature.

DOI： 10.2174/156720211794520224

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

We previously found that N-(4-aminophenyl)-4-trifluoromethyl-benzamide (TFAP), a COX-1 inhibitor, exhibits an analgesic effect without causing gastric damage. Unfortunately, TFAP causes reddish purple coloration of urine, and its analgesic effect is less potent than that of indomethacin. Herein we describe our study focusing on the development of 4- and 5-amino- 2-alkoxy-N-phenylbenzamide scaffolds, designed on the basis of the structures of TFAP and parsalmide, another known COX-1 inhibitory analgesic agent. 5-Amino-2-ethoxy-N-(2-or 3-substituted phenyl) benzamide derivatives exhibited analgesic activity in a murine acetic acid induced writhing test. Among these compounds, 5-amino-2-ethoxy-N-(2-methoxyphenyl) benzamide (9v) possesses potent COX-1 inhibitory and analgesic activities, similar to those of indomethacin. In addition, 5-amino- 2-ethoxy-N-(3-trifluoromethylphenyl)benzamide (9g) showed a more potent analgesic effect than indomethacin or 9v without causing apparent gastric damage or coloration of urine, although its COX-1 inhibitory activity was weaker than that of indomethacin or 9v. Thus, 9g and 9v appear to be promising candidates for analgesic agents and are attractive lead compounds for further development of COX-1 inhibitors.

DOI： 10.1002/cmdc.201000462

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Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：INFORMA HEALTHCARE  

Objective: The pharmacokinetic properties of three newly synthesized retinoid X receptor (RXR) agonists were evaluated in rats to elucidate the structural factor influencing their pharmacokinetic properties. Material and methods: Three RXR agonists possessing a common 6-[N-ethyl-N-(3-alkoxy-4-isopropylphenyl)amino]nicotinic acid skeleton and side chain structures that are slightly different from each other were prepared as we previously reported (Takamatsu et al., ChemMedChem, 2008; 3: 780-787). The plasma concentration profiles of these compounds were evaluated following the intravenous and intra-intestinal administrations. Their hepatic metabolism was characterized using rat liver microsomes. Results: Based on the plasma concentration profile, NEt-3IP (3-isopropoxy) was shown to have a distribution volume of 4.53 L/kg, and to be cleared from the body with an elimination half-time of 0.95 h. The bioavailability of NEt-3IP is 16.4%, whereas those of the isobutoxy analog NEt-3IB and the cyclopropylmethoxy analog NEt-3cPM are 46.5% and 22.6%, respectively. Subsequently, in the experiments using rat liver microsomes, the K-m and V-max values of NEt-3IP were determined as 7.85 mu M and 0.48 nmol/min/mg protein, respectively. This K-m value is nearly the same as those of NEt-3IB and NEt-3cPM, but the V-max value is noticeably smaller. Additionally, it was revealed that the CYP family mainly metabolizing NEt-3IP is different from those metabolizing the other analogs. Conclusion: Based on these findings, the pharmacokinetic properties of the compounds possessing this type of the skeleton seem to be largely influenced by a slight modification of the side chain structure.

DOI： 10.3109/03639045.2011.559247

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Retinoid X receptor (RXR) agonists are interesting candidates for the treatment of metabolic syndrome. 9-Cis-retinoic acid (9cRA: 1) is a natural RXR agonist, that also works as a retinoic acid receptor (RAR) agonist. This fact prompted us to study the structure-activity relationship (SAR) of RXR agonists derived from 1. Though 3 and 4, in which the cyclohexene part of 1 is replaced with bulkier hydrophobic moieties, show RXR-selective agonistic activity, some analogs containing other ring structures show RAR agonistic activity. Thus, we were interested in establishing what kind of ring skeleton is required for RXR-selective agonistic activity. In this study, we systematically prepared 5 and 6, in which the cyclohexene ring of 1 is replaced with various cyclic terpenoid moieties, and evaluated their RXR and RAR agonistic activities. Our previously reported CsF-promoted Stille coupling reaction was employed as a key step for the comprehensive synthesis of 5 and 6. The results of transcriptional assay showed that compounds 5b-f, which possess a menthane skeleton, exhibit RXR-selective agonistic activity. These results should be helpful for the design of superior RXR-selective agonists based on the structure of 1. (C) 2011 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.bmc.2011.03.033

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We discovered a potent retinoid X receptor (RXR) antagonist, 6-[N-ethyl-N-(5-isobutoxy-4-isopropyl-2-(E)-styrylphenyl)amino]nicotinic acid (13e), that is structurally closely related to the RXR full agonist 6-[N-ethyl-N-(3-isobutoxy-4-isopropylphenyl)amino]nicotinic acid (NEt-3IB) (4). Compound 13e was synthesized via a simple route from 11, a methyl ester precursor of 4. Because 11 possesses high electrophilic reactivity because of the amino and alkoxy groups, it was readily transformed to 12 by iodization, and the iodine atom of 12 was converted to a C-C or C-N bond by means of palladium-catalyzed reaction to afford 13. Transcriptional activation assay revealed that 13g (in which the iodine atom was replaced with an amino group) is a weak RXR agonist, while 13d (a phenyl group), 13e (a styryl group), and 13f (an anilino group) are RXR antagonists. Among them, 13e was found to be more potent than the known RXR antagonist PA452 (9).

DOI： 10.1021/ml200197e

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Cyclic trimers of 3-(N-alkylamino)benzoic acid (calix[3]amides) with various substituents at the meta position of the phenyl rings were synthesized and the effects of the substituents on the crystal structures and energy profiles in solution were examined. The calixamides existed in a syn conformation in the crystal state, and this was also the major conformation in solution, especially in polar solvents. The energy barrier between syn and anti conformers in the solution was not significantly affected by substituents (12.7-14.0 kcal/mol). The effect of the substituent on the temperature dependence of the syn/anti ratio are discussed. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2010.08.049

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Retinoid X receptor (RXR) agonists are candidate agents for the treatment of metabolic syndrome and type 2 diabetes via activation of peroxisome proliferator-activated receptor (PPAR)/RXR or liver X receptor (LXR)/RXR-heterodimers, which control lipid and glucose metabolism. Reporter gene assays or binding assays with radiolabeled compounds are available for RXR ligand screening, but are unsuitable for high-throughput screening. Therefore, as a first step towards stabilizing a fluorescence polarization (FP) assay system for high-throughput RXR ligand screening, we synthesized fluorescent RXR ligands by modification of the lipophilic domain of RXR ligands with a carbostyril fluorophore, and selected the fluorescent RXR agonist 6-[ethyl(1-isobutyl-2-oxo-4-trifluoromethyl-1,2-dihydroquinolin-7-yl) amino] nicotinic acid 8d for further characterization. Compound 8d showed FP in the presence of RXR and the FP was decreased in the presence of the RXR agonist LGD1069 (2). This compound should be a lead compound for use in high-throughput assay systems for screening RXR ligands. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.bmcl.2010.07.011

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RXR permissive heterodimers are reported to be activated differently depending upon the chemical structure of RXR agonists, but the relationship of agonist structure to differential heterodimer activation has not been explored in detail. In this study, we performed systematic conversion of the alkoxy side chain of 5a (6-[ethyl-(3-isopropoxy-4-isopropylphenyl)amino]nicotinic acid, NEt-3IP) and evaluated the RXR-, PPAR/RXR-, and LXR/RXR-agonist activities of the products. The cyclopropylmethoxy analogue (5c) showed similar RXR- and LXR/RXR-agonistic activities to the benzyloxy analogue (51) and n-propoxy analogue (5k) but exhibited more potent PPAR/RXR-agonistic activity than 51 or 5k. Differential modulation of RXR heterodimer-activating ability by conversion of the alkoxy group located in the lipophilic domain of the RXR-agonist common structure is expected be a useful approach in the design of new RXR agonists for the treatment of hyperlipidemia or type 2 diabetes.

DOI： 10.1021/ml100184k

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Only a few COX-1-selective inhibitors are currently available, and the research on COX-1 selective inhibitors is not fully developed. The authors have produced several COX-1 selective inhibitors including N-(5-amino-2-pyridinyl)-4-trifluoromethylbenzamide: TFAP (3). Although 3 shows potent analgesic effect without gastric damage, the urine after administration of 3 becomes red-purple. Since the colored-urine should be avoided for clinical use, in this research we examined the cause of the colored-urine. UV-vis spectra and LC-MS/MS analyses of urine samples and metabolite candidates of 3 were performed to afford information that the main reason of the colored urine is a diaminopyridine (4), produced by metabolization of 3. This information is useful to design new COX-1 selective inhibitors without colored urine based on the chemical structure of 3. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.bmcl.2010.01.161

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Previous studies have shown that peroxisome proliferator-activated receptor gamma (PPAR gamma) is involved in allergic rhinitis. It has been reported that 5-aminosalicylate (5-ASA) has an affinity for PPAR gamma, but the effects of 5-ASA on the nasal symptoms of allergic rhinitis are unclear. This study aimed to clarify the effects of 5-ASA on nasal symptoms in an allergic rhinitis model in mice. Female BALB/c mice were sensitized by intraperitoneal injection of ovalbumin (OVA) and aluminium hydroxide hydrate gel (alum) on days 0, 5, 14 and 21. Seven days later, mice were sensitized by the intranasal application of OVA thrice a week. 5-ASA was also administered orally after instillation of the antigen from day 28. The severity of allergic rhinitis was assessed by determining the extent of 2 nasal allergic symptoms-sneezing and nasal rubbing. In addition, serum OVA-specific immunoglobulin E (IgE) antibody, interleukin (IL)-4, and IL-10 levels in nasal lavage fluid and histamine sensitivity were determined. Repeated oral administration of 5-ASA attenuated the progression of nasal symptoms in sensitized mice in a dose-dependent manner. Additionally, 5-ASA prevented an increase in histamine sensitivity. Finally, 5-ASA inhibited both OVA-specific IgE antibody and IL-4 production; however, it had no effect on IL-10 levels. These results indicate that 5-ASA has a prophylactic effect on allergic rhinitis. (C) 2010 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.intimp.2010.03.007

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Retinoid X receptors (RXRs) function as homo-or heterodimers with other nuclear receptors, such as peroxisome proliferator-activated receptors (PPARs), which are targets for treatment of hyperlipidemia and type 2 diabetes, or liver X receptors (LXRs), which are involved in glucose/lipid metabolism. PPAR/RXR or LXR/RXR are known as permissive RXR-heterodimers because they are activated by RXR agonists alone. Interestingly, the pattern of RXR-heterodimer activation is different depending on the RXR agonist structure, but the structure-activity relationship has not been reported. Here we show that modification or replacement of the carboxyl group in the acidic domain of RXR agonists has little or no effect on permissive RXR-heterodimer activation. Phosphonic acid (9), tetrazole (10), and hydroxamic acid (12) analogues were synthesized from the common bromo intermediate 7. Except for 9, these compounds showed RXR full-agonistic activities in the concentration range of 1-10 mu M. The order of agonistic activity toward both PPAR gamma/RXR alpha and LXR alpha/RXR alpha was the same as it was for RXR, that is, 11 &gt; 10 &gt; 12. These results should be useful for the development of RXR agonists with improved bioavailability. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.bmcl.2010.07.012

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Retinoid X receptor (RXR) ligands are attractive candidates for clinical application because of their activity against tamoxifen-resistant breast cancer, taxol-resistant lung cancer, metabolic syndrome, and allergy. Though several RXR ligands, especially RXR antagonists, have been reported, the rational molecular design of such compounds is not well advanced. 4-[N-Methanesulfonyl-N-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-2-naphthyl) amino] nicotinic acid (5a) is a moderately RXR alpha-preferential agonist, and we examined the feasibility of replacing the methyl group on the sulfonamide with a longer alkyl chain or an aromatic ring as an approach to produce new RXR antagonists. Several of the resulting benzenesulfonanilide-type compounds showed RXR antagonist activity. This design strategy should be a useful approach for addressing the lack of structure diversity of RXR antagonists. (C) 2008 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.bmcl.2008.11.086

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：JOHN WILEY & SONS INC  

A benzensulfonanilide-type cyclooxygenase-1 (COX-1)-selective inhibitor, ZXX2-77: 4-amino-4&apos;-chloro-N-methylbenzenesulfonanilide (4a), has been reported as a novel analgesic that does not cause gastric damage. This compound has a weak analgesic effect but has potent in vitro COX-1 inhibitory activity. Since the reason for the weak analgesic effect in vivo was thought to be the low rate of oral absorption, the blood concentration of ZXX2-77 (4a) was measured in rats. It was found that the C(max) value (1.2 mu M) of ZXX2-77 (4a) at a dose of 30 mg/kg did not reach the COX-1 IC(50) value (3.2 mu M). On the other hand, ZXX2-79 (4b) (SO(2)NH derivative of ZXX2-77 (4a); 4-amino-4&apos;-chlorobenzenesulfonanilide), which shows less potent COX inhibitory activities (COX-1 IC(50) = 12 mu M, COX-2 IC(50) = 150 mu M) than those of ZXX2-77 (4a) in vitro, was found to be more absorbable (C(max) - 16 mu M at a dose of 30 mg/kg in rats) than ZXX2-77 (4a). Furthermore, ZXX2-79 (4b) not only showed a potent analgesic effect in a formalin test but also caused little gastric damage. These findings indicate that demethylated sulfonamide compounds are more easily absorbed than are N-methylated sulfonamide compounds and suggest that COX-1-selective inhibitors will be useful as analgesics that do not cause gastric damage. (C) 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:5446-5452, 2008

DOI： 10.1002/jps.21388

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Vancomycin is mainly used as an antibacterial agent of last resort, but recently vancomycin-resistant bacterial strains have been emerging. Although new antimicrobials have been developed in order to overcome drug-resistant bacteria, many are structurally complex beta-lactams or quinolones. In this study, we aimed to create new anti-drug-resistance antibacterials which can be synthesized in a few steps from inexpensive starting materials. Since sulfa drugs function as p-aminobenzoic acid mimics and inhibit dihydropteroate synthase (DHPS) in the folate pathway, we hypothesized that sulfa derivatives would act as folate metabolite-mimics and inhibit bacterial folate metabolism. Screening of our sulfonanilide libraries, including benzenesulfonanilide-type cyclooxygenase-1-selective inhibitors, led us to discover benzenesulfonanilides with potent anti-methicillin-resistant Staphylococcus aureus (MRSA)/vancomycin-resistant Enterococcus (VRE) activity, that is, N-3,5-bis(trifluoromethyl) phenyl-3,5-dichlorobenzenesulfonanilide (16b) [MIC = 0.5 mu g/mL (MRSA), 1.0 mu g/mL (VRE)], and 3,5-bis(trifluoromethyl)-N-(3,5-dichlorophenyl) benzenesulfonanilide (16c) [MIC = 0.5 mu g/mL (MRSA), 1.0 mu g/mL (VRE)]. These compounds are more active than vancomycin [MIC = 2.0 mu g/mL (MRSA), 125 mu g/mL (VRE)], but do not possess an amino group, which is essential for DHPS inhibition by sulfa drugs. These results suggested that the mechanism of antibacterial action of compounds 16b and 16c is different from that of sulfa drugs. We also confirmed the activity of these compounds against clinical isolates of Gram-positive bacteria. (C) 2008 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.bmc.2008.04.040

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Retinoid X receptor agonists (RXR agonists, rexinoids) are interesting candidates for the treatment of cancers such as tomoxifen-resistant breast cancer and taxol-resistant lung cancer. However, well-known RXR agonists possess a strong lipophilic character. In addition, although RXR has three subtypes, no subtype-selective RXR agonists are known. Thus we aimed to produce less-lipophilic and subtype-selective RXR agonists. By designing sulfonamide-type RXR agonists, 4-[N-methanesulfonyl-N-(5,5,8,8-tetromethyl-5,6,7,8-tetrohydro-2-naphthyl)amino]benzoic acid (80) was found to prefer RXR alpha over RXR beta and RXR gamma, although the potency is less than the potencies of well-known RXR pan-agonists. Moreover, our results suggest that the reduction of lipophilicity at the hydrophobic interaction region of RXR agonists enables production of RXR subtype preference. Our finding will be useful for the creation of more potent and less-lipophilic subtype-selective RXR agonists aimed at the reduction of undesirable side effects.

DOI： 10.1002/cmdc.200700265

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Although cyclooxygenase-1 (COX-1) inhibition is thought to be a major mechanism of gastric damage by nonsteroidal anti-inflammatory drugs (NSAIDs), some COX-1-selective inhibitors exhibit strong analgesic effects without causing gastric damage. However, it is not clear whether their analgesic effects are attributable to COX-1-inhibitory activity or other bioactivities. Here, we report that N-(5-amino-2-pyridinyl)-4(trifluoromethyl)benzamide (18f, TFAP), which has a structure clearly different from those of currently available COX-1-selective inhibitors, is a potent COX-1-selective inhibitor (COX-1IC(50) = 0.80 +/- 0.05 mu M, COX-2IC(50) = 210 I mu M). This compound causes little gastric damage in rats even at an oral dose of 300 mg/kg, though it has an analgesic effect at as low a dose as 10 mg/kg. Our results show that COX-1-selective inhibitors can be analgesic agents without causing gastric damage.

DOI： 10.1021/jm701191z

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

Retinoid X receptor (RXR) agonists (rexinoids) ore attracting much attention for their use in treatment of cancers, including tomoxifen-resistant breast cancer and toxol-resistant lung cancer, and metabolic disease. However, known RXR agonists have a highly lipophilic character. In addition, no subtype-selective RXR agonists have been found. We previously reported on RXR alpha-preferential agonist 4-[N-methanesulfonyl-N-(5,5,8,8-tetromethyl-5,6,7,8tetrahydro-2-naphthyl)amino]benzoic acid (6a). The RXR agonistic activity is much less than that of well-known RXR agonists. To develop potent, less-lipophilic, and subtype-selective RXR agonists, we created new RXR agonists possessing alkoxy and isopropyl groups as a lipophilic domain of the common structure of well-known RXR agonists. As a result, compounds possessing branched alkoxy groups, 6-[N-ethyl-N-(3-isopropoxy-4-isopropylphenyl)amino]nicotinic acid (NEt-3IP: 7a) and 6-[N-ethyl-N-(3-isobutoxy-4-isopropylphenyl)amino]nicotinic acid (NEt-3IB: 7c), showed RXR agonistic activity as potent as, or more potent than, the activities of representative RXR agonists. Moreover NEt-3IP (7a) was found to be the first RXR alpha/beta-selective (or RXR alpha/beta-dual) agonist. Being potent, less lipophilic, and having RXR subtype-selective activity, NEt-3IP (7a) is expected to become a new drug candidate and to be a useful biological toot for clarifying each RXR subtype function.

DOI： 10.1002/cmdc.200700313

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Malaria is a leading cause of death in developing countries, and the emergence of strains resistant to the main therapeutic agent, chloroquine, has become a serious problem. We have developed cationic-dimer type antimalarials, MAP-610 and PMAP-H10, which are structurally different from chloroquine. In this study, we introduced several substituents on the terminal phenyl rings of PMAP-H10. The electronic and hydrophobic properties of the substituents were correlated with the antimalarial activity and cytotoxicity of the compounds, respectively. Studies with synchronized cultures of malarial plasmodia showed that our cationic-dimers act selectively between the schizont stage and the ring stage of the parasitic cycle, unlike chloroquine, which has a stage-independent action. Thus, the mechanism of action of our antimalarials appears to be different from that of chloroquine, and our compounds may be effective against chloroquine-resistant strains. (C) 2008 Published by Elsevier Ltd.

DOI： 10.1016/j.bmc.2008.04.051

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DOI： 10.1002/cmdc.200800095

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DOI： 10.1002/cmdc.200800095

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Authorship：Last author,　Corresponding author   Language：English   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

DOI： 10.1016/j.bmc.2007.01.059

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Malaria is one of the three major serious infectious diseases in the world. As the area affected by malaria includes a large proportion of developing countries, there is a need for new antimalarials that can be synthesized and supplied inexpensively. To generate low-cost antimalarials, the MAP series 6-10, bis-cation dimers, synthesized by amidating the carboxyl group of isonicotinic acid (11) with various amines and by cationizing the nitrogen atoms of the pyridine ring with the corresponding alkyl bromides, were designed. This design enabled expansion of the structural variations of bis-cation-type antimalarial compounds. The compounds bearing alkyl or phenyl groups in the amide moieties showed remarkable antimalarial activities in vitro. Moreover, 1, 1'-(1, 12-dodecanediyl)bis[4-[(buthylamino)carbonyl]pyridinium bromide], MAP-412 (6d), exhibited a potent antimalarial activity (ED50 = 8.2 mg kg-(1)). Being prepared at low cost our biscation-type antimalarial compounds may be useful as lead compounds for inexpensive antimalarials.

DOI： 10.1002/cmdc.200700107

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

In order to create novel analgesic agents without gastric disturbance, structurally simple cyclooxygenase-1 (COX-1) inhibitors with a benzenesulfonanilide skeleton were designed and synthesized. As a result, compounds 11f and 15a, which possess a p-amino group on the benzenesulfonyl moiety and p-chloro group on the anilino moiety, showed COX-1-selective inhibition. Moreover compound 11f, which is the most potent compound in this study showed more potent analgesic activity than that of aspirin at 30 mg/kg by po. The anti-inflammatory activity and gastric damage, however, were very weak or not detectably different from aspirin. Since the structure of our COX-1 inhibitors are very simple, they may be useful as lead compounds for superior COX-1 inhibitors as analgesic agents without gastric disturbance. (c) 2006 Published by Elsevier Ltd.

DOI： 10.1016/j.bmc.2006.10.029

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

The in vitro antimalarial activity of bis-pyridinium salts, N,N'-hexamethylenebis(4-carbamoyl-1-decylpyridinium bromide) and their derivatives, against the Plasmodium falciparum FCR-3 strain (ATCC 30932, chloroquine-sensitive) was evaluated. All test compounds exhibited antimalarial activity over a concentration range of 3.5 mu M to 10 nM. The chain length of the N1-alkyl moiety was found to be very beneficial in terms of antimalarial activity, and in this series of compounds, the most appropriate N1-alkyl chain length was found to be eight. (C) 2006 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.bmcl.2006.02.030

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

The cytotoxicity of non-steroidal anti-inflammatory drugs (NSAIDs) is involved in the formation of NSAID-induced gastric lesions. The mechanism(s) behind these cytotoxic effects, however, is not well understood. We found here that several NSAIDs tested caused hemolysis when employed at concentrations similar to those that result in cytotoxicity. Moreover, these same NSAIDs were found to directly permeabilize the membranes of calcein-loaded liposomes. Given the similarity in NSAID concentrations for cytotoxic and membrane permeabilization effects, the cytotoxic action of these NSAIDs may be mediated through the permeabilization of biological membranes. Increase in the intracellular Ca2+ level can lead to cell death. We here found that all of NSAIDs tested increased the intracellular Ca2+ level at concentrations similar to those that result in cytotoxicity. Based on these results, we consider a possibility that membrane permeabilization by NSAIDs induces cell death through increase in the intracellular Ca2+ level. (C) 2004 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bbrc.2004.08.205

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PHARMACEUTICAL SOC JAPAN  

Potent, specific, chemically stable and non-peptide/small-molecular inhibitors of puromycin-sensitive aminopeptidase, such as 3-(2,6-diethylphenyl)-2,4(1H,3H)-quinazolinedione (PAQ-22, 5), were prepared by the structural development of a potent PSA inhibitor, 2-(2,6-diethylphenyl)-1,2,3,4-tetrahydroisoquinoline-1,3-dione (PIQ-22, 4). The design was carried out partly by applying electrostatic potential field information obtained from PIQ-22 (4) and its derivatives based on thalidomide (2). This information revealed that a positive electrostatic potential field around the benzylic methylene in the tetrahydroisoquinoline ring is necessary for potent activity. Lineweaver-Burk plot analysis showed that PAQ-22 (5) and its derivatives inhibit puromycin-sensitive aminopeptidase (PSA) in a non-competitive manner. These potent and specific PSA inhibitors showed dose-dependent cell invasion-inhibitory activity in a Matrigel assay using mouse melanoma B16F10/L5 cells, in spite of their low cell toxicity.

DOI： 10.1248/cpb.51.1273

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Several N-3,5-dimethylphenylphthalimide analogs possessing more potent cyclooxygenase-inhibiting activity than that of aspirin were prepared during structural development studies based on thalidomide. Substituent effects on the activity were investigated.

DOI： 10.1248/cpb.51.1098

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Non-peptide, small-molecular, non-competitive inhibitors of puromycin-sensitive aminopeptidase (PSA), that is, 3-(2,6-diethylphenyl)-2,4(1H,3 H)-quinazolinedione (PAQ-22, 3) and its 1N-methyl analogue (MPAQ-22 4), were structurally modified to afford fluorescent bioprobes, ANTAQ (5) and DAMPAQ-22 (6). The cellular localization of PSA could be visualized by the use of these fluorescent bioprobes. (C) 2002 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/s0960-894x(02)00845-4

DOI： 10.1016/S0960-894X(02)00845-4

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

2-(2,6-Diethylphenyl)-1,2,3,4-tetrahydroisoquinoline-1,3-dione (2: PIQ-22) was found to be a potent and specific inhibitor of puromycin-sensitive aminopeptidase (PSA). Lineweaver-Burk plot analysis showed that PSA is inhibited by PIQ-22 in a non-competitive manner. Structure-activity relationship studies indicated that tautomerism of the imidobenzoylketone group in the cyclic imide moiety of the PIQ-22 skeleton is important for the inhibitory activity. (C) 2000 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0968-0896(00)00231-5

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Institute of Heterocyclic Chemistry  

Novel specific PSA (puromycin-sensitive aminopeptidase) inhibitors, 3-(2,6-diethylphenyl)-2,4(1H, 3H)-quinazolinedione (3: PAQ-22) and N-(2,6-diethylphenyl)-2-amino-4H-3,1-benzoxazin-4-one (4: PAZOX-22), were designed and synthesized. These compounds are chemically much more stable than the known specific PSA inhibitor PIQ-22 (2), and the enzyme specificity and inhibitory activity to PSA are similar to those of 2. The inhibitory manner of these compounds was found to be a non-competitive mode by Lineweaver- Burk plot analysis.

DOI： 10.3987/com-01-9247

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier Ltd  

Tetraguanidines (1 and 2) with an aromatic multilayered structure exhibit potent binding to a specific site of DNAS with binding constants of the order of 107 M-1 as deduced from Scatchard analysis of ultrafiltration data and simulation of CD titration curves. NMR spectra of the complexes indicated that 1 and 2 bind DNAs sequence-specifically at the minor groove, as predicted by computational docking studies.

DOI： 10.1016/s0040-4039(98)01378-1

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：AMER CHEMICAL SOC  

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Bexaroteneは、皮膚浸潤性T細胞リンパ腫の他、メタボリックシンドロームに対する治療効果などが報告されている。一方で、レチノイドX受容体(RXR)を標的とすることで、多種多様な受容体との相互作用によって思わぬ副作用が生じかねない。著者は、創薬標的に作用する化合物について構造展開を図ることで副作用の回避法などを探り、当該標的ならびに創出される化合物を新たな創薬標的またリード化合物として提示する手法を「リバイバル創薬」と称し、その一環としてレチノイド研究に取り組んだ。これまで行ってきたRXRを標的とする創薬研究について概説した。

DOI： 10.20632/vso.90.3_101

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Other Link： http://search.jamas.or.jp/link/ui/2016224078

Language：Japanese   Publisher：(一社)日本呼吸器学会  

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To grow beyond a size of approximately 1-2 mm(3), tumor cells activate many processes to develop blood vasculature. Growing evidences indicate that the formation of the tumor vascular network is very complex, and is not restricted to angiogenesis. Cancer cell-derived tumor vasculatures have been recently described. Among them, endothelial differentiation of tumor cells have been directly related to cancer stem cells, which are cells within a tumor that possess the capacity to self-renew, and to exhibit multipotential heterogeneous lineages of cancer cells. Vasculogenic mimicry has been described to be formed by cancer cells expressing stemness markers. Thus, cancer stem cells have been proposed to contribute to vasculogenic mimicry, though its relation is yet to be clarified. Here, we analyzed the tumor vasculature by using a model of mouse cancer stem cells, miPS-LLCcm cells, which we have previously established from mouse induced pluripotent stem cells and we introduced the DsRed gene in miPS-LLCcm to trace them in vivo. Various features of vasculature were evaluated in ovo, in vitro, and in vivo. The tumors formed in allograft nude mice exhibited angiogenesis in chick chorioallantoic membrane assay. In those tumors, along with penetrated host endothelial vessels, we detected endothelial differentiation from cancer stem cells and formation of vasculogenic mimicry. The angiogenic factors such as VEGF-A and FGF2 were expressed predominantly in the cancer stem cells subpopulation of miPS-LLCcm cells. Our results suggested that cancer stem cells play key roles in not only the recruitment of host endothelial vessels into tumor, but also in maturation of endothelial linage of cancer stem cell's progenies. Furthermore, the undifferentiated subpopulation of the miPS-LLCcm participates directly in the vasculogenic mimicry formation. Collectively, we show that miPS-LLCcm cells have advantages to further study tumor vasculature and to develop novel targeting strategies in the future.

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DOI： 10.20632/vso.89.12_595_2

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Language：Japanese   Publisher：日本結合組織学会  

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DOI： 10.20632/vso.89.4_177

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Introduction: Retinoid X receptors (RXRs) are nuclear receptors that act as ligand-dependent transcription factors. RXRs function as homodimers or as heterodimers with other nuclear receptors, such as retinoic acid receptors, PPARs, liver X receptors, farnesoid X receptor, vitamin D receptor or thyroid hormone receptors. RXR ligands (agonists or antagonists) show various physiological effects, depending on their partner receptors. RXR agonist bexarotene (Targretin (R)) is used for the treatment of cutaneous T-cell lymphoma in clinical practice. RXR agonists were also reported to be useful for treatment of type 2 diabetes, autoimmune disease and Alzheimer's disease. RXR antagonists were also reported to be effective in type 2 diabetes treatment.
Areas covered: Here patent applications (2007 - 2013) concerning RXR ligands are summarized, and the usefulness of RXR ligands as pharmaceutical agents is discussed.
Expert opinion: RXR agonists show a wide variety of biological effects. However, they cause serious side effects, such as blood triglyceride elevation, hypothyroidism and others. Thus, for clinical application of RXR agonists, abrogation of these side effects is required. RXR heterodimer-selective agonists and RXR partial agonists exhibiting desired effects without side effects are expected to find clinical application.

DOI： 10.1517/13543776.2014.880692

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DOI： 10.1158/1538-7445.AM2012-946

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著者等は1型・2型糖尿病を問わず有用な化合物創出を目的に、レチノイドX受容体(RXR)に注目して研究を行っている。RXRは自身のホモダイマー、もしくはPPAR(ペルオキシソーム増殖因子活性化受容体)、LXR(肝臓X受容体)などとヘテロダイマーを形成して機能する。各種アルコキシ基を有するRXRアゴニストのRXR活性化能、更に同程度のRXR活性を有する化合物のPPAR/RXRおよびLXR/RXR活性について概説した。

DOI： 10.1248/yakushi.131.917

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Language：Japanese   Publisher：(公社)日本薬学会  

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Language：Japanese   Publishing type：Book review, literature introduction, etc.   Publisher：(公社)日本薬学会  

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used to relieve physical and mental pain, and to improve patients' quality of life. However, stomach irritation is a major side effect. Most NSAIDs inhibit cyclooxygenases (COXs), and inhibition of COX-1 on the stomach mucous membrane is thought to be responsible for the gastric disturbance. Consequently, development efforts have focused on COX-2-selective inhibitors, while COX-1-selective inhibitors have been rather neglected. Subsequently, however, it was shown that inhibition of either COX-1 or COX-2 alone does not induce gastric damage. Therefore, we have developed the COX-1-selective inhibitor N-(4-aminophenyl)-4- trifluoromethylbenzamide (TFAP), which shows analgesic activity without causing gastric damage. However, metabolism of TFAP generates a colored metabolite, resulting in red-purple coloration of urine after administration. In addition, the analgesic activity of TFAP is weaker than that of indomethacin. Thus, we designed a series of new COX-1-selective inhibitors, the 5-amino-2-ethoxy-N- (substituted)benzamide (ABEX) series, in order to avoid formation of the colored metabolite by modifying the diaminopyridine skeleton. As a result of structural modification and in vitro and in vivo testing of compounds in the ABEX series, we found a novel COX-1-selective inhibitor, 5-amino-2-ethoxy-N-(3- trifluoromethylphenyl)benzamide (ABEX-3TF), which shows better analgesic activity than indomethacin, and does not cause coloration of urine. © 2011 The Pharmaceutical Society of Japan.

DOI： 10.1248/yakushi.131.347

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It might be seen as reckless to challenge to create single-agents for the treatment of both type I diabetes caused by the destruction of the Langerhans,3 cells in pancreas by excessive autoimmunity, and type 2 diabetes caused by the obesity. However, we hypothesized that retinoid X receptor (RXR) agonists, which are researched for the treatment of type 2 diabetes, will also be useful like metformin, which shows insulin-sparing effect in type 1 diabetes. This is because PPAR gamma/RXR is known to be a target of thiazolidinediones (TZDs), which are used for the treatment of insulin resistance, LXR/RXR is reported to be involved in glucose/lipid metabolism, and these heterodimers can be activated by RXR agonists alone (permissive mechanism). However, repeated administration of RXR agonists can elevate blood triglyceride and induce hypothyroidism. In this study, we performed systematic conversion of the alkoxy side chain of 5a (6-[ethyl- (3-isopropoxy-4-isopropylphenyl)amino] nicotinic acid: NEt-3IP) and evaluated the RXR-, PPAR/RXR- and LXR/RXR-agonist activities of the products. The cyclopropylmethoxy analog (5c) showed similar RXR- and LXR/RXR-agonistic activities to the benzyloxy analog (51) and n-propoxy analog (5k), but exhibited more potent PPAR/RXR-agonistic activity than 51 or 5k. Differential modulation of RXR heterodimer-activating ability by conversion of the alkoxy group located in the lipophilic domain of the RXR-agonist common structure is expected to be a useful approach in the design of new RXR agonists for the treatment of hyperlipidemia.

DOI： 10.1248/yakushi.131.917

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Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used to relieve physical and mental pain, and to improve patients' quality of life. However, stomach irritation is a major side effect. Most NSAIDs inhibit cyclooxygenases (COXs), and inhibition of COX-1 on the stomach mucous membrane is thought to be responsible for the gastric disturbance. Consequently, development efforts have focused on COX-2-selective inhibitors, while COX-1-selective inhibitors have been rather neglected. Subsequently, however, it was shown that inhibition of either COX-1 or COX-2 alone does not induce gastric damage. Therefore, we have developed the COX-1-selective inhibitor N-(4-aminophenyl) -4-trifluoromethylbenzamide (TFAP), which shows analgesic activity without causing gastric damage. However, metabolism of TFAP generates a colored metabolite, resulting in red-purple coloration of urine after administration. In addition, the analgesic activity of TFAP is weaker than that of indomethacin. Thus, we designed a series of new COX-1-selective inhibitors, the 5-amino-2-ethoxy-N- (substituted) benzamide (ABEX) series, in order to avoid formation of the colored metabolite by modifying the diaminopyridine skeleton. As a result of structural modification and in vitro and in vivo testing of compounds in the ABEX series, we found a novel COX-1-selective inhibitor, 5-amino-2-ethoxy-N-(3-trifluoromethylphenyl) benzamide (ABEX-3TF), which shows better analgesic activity than indomethacin, and does not cause coloration of urine.

DOI： 10.1248/yakushi.131.347

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Language：Japanese   Publishing type：Book review, literature introduction, etc.   Publisher：PHARMACEUTICAL SOC JAPAN  

The studies on both structure-activity relationship study and identification of the target enzyme of novel nonpeptide aminopeptidase inhibitors with cyclic imide skeleton are reviewed. Some N-phenylphthalimide or N-phenylhomophthalimide derivative showed potent protease inhibitory activity in an assay system using human acute lymphoblastic leukemia cells, Molt-4, with alanin-4-methylcoumaryl-7-amide (ala-AMC) as a substrate. Especially, 2-(2,6-diethylphenyl)-1,2,3,4-tetrahydroisoquinoline-1, 3-dione (PIQ-22) (3) was found to be the most potent inhibitor and further it showed potent tumor-cell invasion inhibitory activity that is more effective than potent peptide aminopeptidase inhibitors such as bestatin (1) or actinonin (2). For the further investigation of this novel protease inhibitory activity, we have carried out the structural development of PIQ-22 (3) and it is assumed that tautomerism of imidobenzoylketone in cyclic imide structure may be related to the inhibitory activity. The requirement for the activity of electron donating groups such as NH2 or OH to the condensed phenyl ring in phthalimide inhibitors also supports this possibility. The target aminopeptidase of PIQ-22 was identified as puromycin-sensitive aminopeptidase (PSA), by N-terminal amino acid sequencing, and by comparison with chromatographic behavior and substrate-selectivity, and so on. Lineweaver-Burk plot showed that PSA is inhibited by PIQ-22 (3) in a noncompetitive manner while puromycin (83) and bestatin (1) inhibit PSA competitively.

DOI： 10.1248/yakushi1947.120.10_909

Web of Science

CiNii Article

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Language：Japanese   Publishing type：Book review, literature introduction, etc.   Publisher：PHARMACEUTICAL SOC JAPAN  

The studies on both structure-activity relationship study and identification of the target enzyme of novel nonpeptide aminopeptidase inhibitors with cyclic imide skeleton are reviewed. Some N-phenylphthalimide or N-phenylhomophthalimide derivative showed potent protease inhibitory activity in an assay system using human acute lymphoblastic leukemia cells, Molt-4, with alanin-4-methylcoumaryl-7-amide (ala-AMC) as a substrate. Especially, 2-(2,6-diethylphenyl)-1,2,3,4-tetrahydroisoquinoline-1, 3-dione (PIQ-22) (3) was found to be the most potent inhibitor and further it showed potent tumor-cell invasion inhibitory activity that is more effective than potent peptide aminopeptidase inhibitors such as bestatin (1) or actinonin (2). For the further investigation of this novel protease inhibitory activity, we have carried out the structural development of PIQ-22 (3) and it is assumed that tautomerism of imidobenzoylketone in cyclic imide structure may be related to the inhibitory activity. The requirement for the activity of electron donating groups such as NH2 or OH to the condensed phenyl ring in phthalimide inhibitors also supports this possibility. The target aminopeptidase of PIQ-22 was identified as puromycin-sensitive aminopeptidase (PSA), by N-terminal amino acid sequencing, and by comparison with chromatographic behavior and substrate-selectivity, and so on. Lineweaver-Burk plot showed that PSA is inhibited by PIQ-22 (3) in a noncompetitive manner while puromycin (83) and bestatin (1) inhibit PSA competitively.

DOI： 10.1248/yakushi1947.120.10_909

Web of Science

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Applicant：国立大学法人 岡山大学

Application no：JP2016060309  Date applied：2016.3.30

Announcement no：WO2016-170938  Date announced：2016.10.27

Patent/Registration no：特許第6161828号  Date issued：2017.6.23

J-GLOBAL

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Applicant：国立大学法人 岡山大学

Application no：JP2013056974  Date applied：2013.3.13

Announcement no：WO2013-137302  Date announced：2013.9.19

Patent/Registration no：特許第6112427号  Date issued：2017.3.24

J-GLOBAL

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Applicant：国立大学法人 岡山大学

Application no：特願2012-043411  Date applied：2012.2.29

Announcement no：特開2013-180951  Date announced：2013.9.12

Patent/Registration no：特許第5877466号  Date issued：2016.2.5

J-GLOBAL

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Applicant：国立大学法人 岡山大学

Application no：特願2012-041353  Date applied：2012.2.28

Announcement no：特開2013-177329  Date announced：2013.9.9

Patent/Registration no：特許第5885140号  Date issued：2016.2.19

J-GLOBAL

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Applicant：国立大学法人 岡山大学

Application no：特願2012-507079  Date applied：2011.3.25

Announcement no：WO2011-118759  Date announced：2011.9.29

Patent/Registration no：特許第5745501号  Date issued：2015.5.15

J-GLOBAL

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Applicant：国立大学法人 岡山大学

Application no：JP2009005235  Date applied：2009.10.8

Announcement no：WO2010-041449  Date announced：2010.4.15

Patent/Registration no：特許第5542059号  Date issued：2014.5.16

J-GLOBAL

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Applicant：国立大学法人 岡山大学

Application no：特願2008-282792  Date applied：2008.11.4

Announcement no：特開2010-111588  Date announced：2010.5.20

Patent/Registration no：特許第5255994号  Date issued：2013.4.26

J-GLOBAL

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Applicant：国立大学法人 岡山大学

Application no：特願2006-276588  Date applied：2006.10.10

Announcement no：特開2008-094740  Date announced：2008.4.24

Patent/Registration no：特許第4431796号  Date issued：2010.1.8

J-GLOBAL

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Application no：特願2018-553029 

Announcement no：PCT/JP2017/043220 

Patent/Registration no：特許第6548060号 

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Country：Japan

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Type：Peer review 

Type：Peer review 

Type：Peer review