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Mutations in the type 1 ryanodine receptor (RyR1), a Ca2+ release channel in skeletal muscle, hyperactivate the channel to cause malignant hyperthermia (MH) and are implicated in severe heat stroke. Dantrolene, the only approved drug for MH, has the disadvantages of having very poor water solubility and long plasma half-life. We show here that an oxolinic acid-derivative RyR1-selective inhibitor, 6,7-(methylenedioxy)-1-octyl-4-quinolone-3-carboxylic acid (Compound 1, Cpd1), effectively prevents and treats MH and heat stroke in several mouse models relevant to MH. Cpd1 reduces resting intracellular Ca2+, inhibits halothane- and isoflurane-induced Ca2+ release, suppresses caffeine-induced contracture in skeletal muscle, reduces sarcolemmal cation influx, and prevents or reverses the fulminant MH crisis induced by isoflurane anesthesia and rescues animals from heat stroke caused by environmental heat stress. Notably, Cpd1 has great advantages of better water solubility and rapid clearance in vivo over dantrolene. Cpd1 has the potential to be a promising candidate for effective treatment of patients carrying RyR1 mutations., Mutations in ryanodine receptor 1 (RyR1), a Ca2+ release channel in skeletal muscle, cause malignant hyperthermia (MH) and are involved in heat stroke. Here, the authors show that an oxolinic acid-derivative RyR1 inhibitor effectively prevents and treats MH and heat stroke in various MH mouse models.

A classical drug repurposing approach was applied to find new putative GPR40 allosteric binders. A two-step computational protocol was set up, based on an initial pharmacophoric-based virtual screening of the DrugBank database of known drugs, followed by docking simulations to confirm the interactions between the prioritised compounds and GPR40. The best-ranked entries showed binding poses comparable to that of TAK-875, a known allosteric agonist of GPR40. Three of them (tazarotenic acid, bezafibrate, and efaproxiral) affect insulin secretion in pancreatic INS-1 832/13 β-cells with EC50 in the nanomolar concentration (5.73, 14.2, and 13.5 nM, respectively). Given the involvement of GPR40 in type 2 diabetes, the new GPR40 modulators represent a promising tool for therapeutic intervention towards this disease. The ability to affect GPR40 was further assessed in human breast cancer MCF-7 cells in which this receptor positively regulates growth activities (EC50 values were 5.6, 21, and 14 nM, respectively).

Squaramide is a highly rigid four-membered ring system bearing two carbonyl and two amino groups, and its derivatives have found applications in many fields. We synthesized several N,N'-dimethylated oligosquaramides linked via phenyl groups, and investigated their structures in the crystalline state and in solution. Compounds 1, 2 (bissquaramides), and 13 (trissquaramide) exist as folded structures in the crystalline state, in which the aromatic rings are located in a face-to-face position. In their multilayered structures, the benzene rings are more nearly parallel and are closer to each other, compared with those in N,N'-dimethylated oligoureas. Individual molecules of meta-connected compounds 2 and 13 show a helical structure with all-R or all-S axis chirality, but afford only racemic crystals. The NMR spectra indicated that these compounds retain well-ordered folded structures in solution. The unique steric and electronic properties of N,N'-dimethylated squaramide can provide access to novel functional aromatic multilayered and helical foldamers.

Lithocholic acid (2) was identified as a second endogenous ligand of vitamin D receptor (VDR), though its activity is very weak. In this study, we designed novel lithocholic acid derivatives based on the crystal structure of VDR-ligand-binding domain (LBD) bound to 2. Among the synthesized compounds, 6 bearing a 2-hydroxy-2-methylprop-1-yl group instead of the 3-hydroxy group at the 3α-position of 2 showed dramatically increased activity in HL-60 cell differentiation assay, being at least 10 000 times more potent than lithocholic acid (2) and 3 times more potent than 1α,25-dihydroxyvitamin D3 (1). Although the binding affinities of 6 and its epimer 7 were less than that of 1, their transactivation activities were greater than that of 1. X-ray structure analyses of VDR LBD bound to 6 or 7 showed that the binding positions of these compounds in the ligand-binding pocket are similar to that of 1.

Coumarin has been utilized as a core structure of photofunctional molecules, such as fluorescent sensors and photoremovable protecting groups. Here, we show that the 6-arylcoumarin moiety can provide OFF-ON-OFF type regulatory functionality for such compounds. To illustrate its utility, we synthesized a coumarin derivative bearing two phenolic hydroxy groups at 7-position and on 6-aryl group as a fluorescent sensor showing an OFF-ON-OFF change in fluorescence intensity in response to an increase in pH from a strongly acidic condition. Further, we show that the efficiency of photoreaction of other derivatives with the same hydroxyl groups is switched from "OFF" at pH 3 and 6 to "ON" at pH 9 and then to OFF at pH 12, enabling their application as switchable photoremovable protective groups. These features arise from sequential deprotonation of two hydroxyl groups: the monoanionic form is responsible for the photoinduced fluorescence and photoreaction.

β-Catenin is an important component of the Wnt signalling pathway. As dysregulation or mutation of this pathway causes many diseases, including cancer, the β-Catenin level is carefully regulated by the destruction complex in the Wnt signalling pathway. However, the mechanisms underlying the regulation of β-Catenin ubiquitination and degradation remain unclear. Here, we find that WNK (With No Lysine [K]) kinase is a potential regulator of the Wnt signalling pathway. We show that WNK protects the interaction between β-Catenin and the Glucose-Induced degradation Deficient (GID) complex, which includes an E3 ubiquitin ligase targeting β-Catenin, and that WNK regulates the β-Catenin level. Furthermore, we show that WNK inhibitors induced β-Catenin degradation and that one of these inhibitors suppressed xenograft tumour development in mice. These results suggest that WNK is a previously unrecognized regulator of β-Catenin and a therapeutic target of cancer., Sato et al. find that WNK (With No Lysine [K]) acts as a positive regulator of the Wnt signaling pathway by attenuating the interaction between β-Catenin and the Glucose Induce degradation Deficient (GID) complex, and show that a WNK inhibitor also functions as a Wnt inhibitor, suppressing xenograft tumor development in mice. These findings suggest that WNK is a regulator of β-Catenin and a potential therapeutic target

The progesterone receptor (PR) plays an important role in various physiological processes, especially in the female reproductive system, and abnormalities of PR function are associated with several diseases, including some types of cancer. Non-steroidal PR ligands are of interest as candidate drugs for treatment of PR-related diseases without the serious adverse effects that may be caused by steroidal ligands. For the development of non-steroidal PR ligands, both a hydrophobic backbone and a polar functional group corresponding to the 3-carbonyl group of progesterone, which interacts with Gln725 and Arg766 of the PR-ligand binding domain, are critically important. We previously showed that carborane is a useful hydrophobic pharmacophore for PR antagonists, and in this work, we introduced the pentafluorosulfanyl (SF5) group as a novel polar functional group of carborane-based non-steroidal PR antagonists. All the synthesized SF5-containing carborane derivatives exhibited PR-antagonistic activity at micromolar or submicromolar concentration. Among them, compounds 11 are potent progesterone antagonists with submicromolar IC50 values.

Type-1 ryanodine receptor (RyR1) is a calcium-release channel localized on sarcoplasmic reticulum (SR) of the skeletal muscle, and mediates muscle contraction by releasing Ca2+ from the SR. Genetic mutations of RyR1 are associated with skeletal muscle diseases such as malignant hyperthermia and central core diseases, in which over-activation of RyR1 causes leakage of Ca2+ from the SR. We recently developed an efficient high-throughput screening system based on the measurement of Ca2+ in endoplasmic reticulum, and used it to identify oxolinic acid (1) as a novel RyR1 channel inhibitor. Here, we designed and synthesized a series of quinolone derivatives based on 1 as a lead compound. Derivatives bearing a long alkyl chain at the nitrogen atom of the quinolone ring and having a suitable substituent at the 7-position of quinolone exhibited potent RyR1 channel-inhibitory activity. Among the synthesized compounds, 14h showed more potent activity than dantrolene, a known RyR1 inhibitor, and exhibited high RyR1 selectivity over RyR2 and RyR3. These compounds may be promising leads for clinically applicable RyR1 channel inhibitors.

Background Intercellular communications are important for maintaining normal physiological processes. An important intercellular communication is mediated by the exchange of membrane-enclosed extracellular vesicles. Among various vesicles, exosomes can be detected in a wide variety of biological systems, but the regulation and biological implication of exosome secretion/uptake remains largely unclear. Methods Cellular retinoic acid (RA) binding protein 1 (Crabp1) knockout (CKO) mice were used for in vivo studies. Extracellular exosomes were monitored in CKO mice and relevant cell cultures including embryonic stem cell (CJ7), macrophage (Raw 264.7) and hippocampal cell (HT22) using Western blot and flow cytometry. Receptor Interacting Protein 140 (RIP140) was depleted by Crispr/Cas9-mediated gene editing. Anti-inflammatory maker was analyzed using qRT-PCR. Clinical relevance was accessed by mining multiple clinical datasets. Results This study uncovers Crabp1 as a negative regulator of exosome secretion from neurons. Specifically, RIP140, a pro-inflammatory regulator, can be transferred from neurons, via Crabp1-regulated exosome secretion, into macrophages to promote their inflammatory polarization. Consistently, CKO mice, defected in the negative control of exosome secretion, have significantly elevated RIP140-containing exosomes in their blood and cerebrospinal fluid, and exhibit an increased vulnerability to systemic inflammation. Clinical relevance of this pathway is supported by patients’ data of multiple inflammatory diseases. Further, the action of Crabp1 in regulating exosome secretion involves its ligand and is mediated by its downstream target, the MAPK signaling pathway. Conclusions This study presents the first evidence for the regulation of exosome secretion, which mediates intercellular communication, by RA-Crabp1 signaling. This novel mechanism can contribute to the control of systemic inflammation by transferring an inflammatory regulator, RIP140, between cells. This represents a new mechanism of vitamin A action that can modulate the homeostasis of system-wide innate immunity without involving gene regulation.

Hypertension is an important target for drug discovery. We have focused on the with-no-lysine kinase (WNK)-oxidative stress-responsive 1 (OSR1) and STE20/SPS1-related proline-alanine-rich protein kinase (SPAK)-NaCl cotransporter (NCC) signal cascade as a potential target, and we previously developed a screening system for inhibitors of WNK-OSR1/SPAK-NCC signaling. Herein we used this system to examine the structure-activity relationship (SAR) of salicylanilide derivatives as SPAK kinase inhibitors. Structural design and development based on our previous hit compound, aryloxybenzanilide derivative 2, and the veterinary anthelmintic closantel (3) led to the discovery of compound 10 a as a potent SPAK inhibitor with reduced toxicity. Compound 10 a decreased the phosphorylation level of NCC in mouse kidney in vivo, and appears to be a promising lead compound for a new class of antihypertensive drugs.

N,N′-Bis(ortho-substituted phenyl)squaramides afforded chiral crystals, in which squaramide molecules are arranged in one-handed helical networks, upon simple recrystallization. Three types of crystals with different helices were obtained, depending on the substituents or recrystallization solvent. Folded-type intermolecular hydrogen-bonding interactions of squaramides play a key role in forming the helical networks.

Vitamin K (VK), in both its phylloquinone and menaquinone forms, has been hypothesized to undergo ω- and β-oxidation on its hydrophobic side chain in order to generate the observed urinary metabolites, K acid I and K acid II, which are excreted primarily as glucuronide conjugates. Synthetic standards of K acid I, K acid II, and a putative intermediate metabolite, menaquinone (MK)1 ω-COOH, were used to develop and optimize a new atmospheric pressure negative chemical ionization LC-MS/MS assay for the quantitation of these compounds in urine from untreated individuals and subjects treated with a high dose VK supplement. VK catabolites were extracted from urine, deconjugated, and converted to their methyl ester derivatives using previously reported methodology. The assay showed a high degree of sensitivity, with limits of detection below 10–50 fmol of metabolite per milliliter of urine, as well as an inter-assay precision of 8–12%. Metabolite standards provided unambiguous evidence for MK1 ω-COOH as a new human urinary metabolite of VK. This assay provides a minimally invasive, highly sensitive, and specific alternative for monitoring VK status in humans.

The androgen receptor (AR) is a ligand-inducible transcription factor belonging to the nuclear receptor superfamily, and is a target molecule for development of drugs to treat prostate cancer. However, AR antagonists in clinical use, such as flutamide (3a) and bicalutamide (4), encounter resistance after several years of hormone therapy, predominantly due to mutations of AR. Thus, although some new-generation AR antagonists have been developed, novel types of AR antagonists are still required to treat drug-resistant prostate cancer. We previously reported a novel (benzoylaminophenoxy)phenol derivative 10a, which is structurally distinct from conventional AR antagonists. Here, we systematically examined the structure-activity relationship of (benzoylaminophenoxy)phenol derivatives on the inhibitory activity on the prostate cancer cell proliferations. We found that the 4-[4-(benzoylamino)phenoxy]phenol backbone is important for anti-prostate cancer activity. Introduction of a small substituent at the 2 position of the central benzene ring (B ring) increases the activity. Among the synthesized compounds, 19a and 19b exhibited the most potent inhibitory activity toward dihydrotestosterone-induced proliferation of several androgen-dependent cell lines, SC-3 (wild-type AR), LNCaP (T877A AR), and 22Rv1 (H874Y AR), but interestingly also inhibited proliferation of AR-independent PC-3 cells. These compounds, which have a different pharmacophore from conventional AR antagonists, are promising drug candidates for the treatment of prostate cancer.

New chemotherapeutics are needed to treat hepatocellular carcinoma (HCC), and menaquinones, homologs of vitamin K consisting of a 1,4-naphthoquinone core and a (poly)isoprene chain, are potential candidates. In this study, we designed and synthesized a series of phthalazine-1,4-dione-based menaquinone analogs. Among them, compounds bearing the intact isoprene chain exhibited selective antiproliferative activity towards HCC cell line JHH7, as compared with normal hepatocytes. The geranyl derivative 10 showed submicromolar potency, and might be a promising lead compound for anticancer agents.

The transcriptional coactivator with PDZ-binding motif (TAZ) (WWTR1) induces epithelial–mesenchymal transition and enhances drug resistance in multiple cancers. TAZ has been shown to interact with transcription factors in the nucleus, but when phosphorylated, translocates to the cytoplasm and is degraded through proteasomes. Here, we identified a compound TAZ inhibitor 4 (TI-4) that shifted TAZ localization to the cytoplasm independently of its phosphorylation. We used affinity beads to ascertain a putative target of TI-4, chromosomal segregation 1 like (CSE1L), which is known to be involved in the recycling of importin α and as a biomarker of cancer malignancy. We found that TI-4 suppressed TAZ-mediated transcription in a CSE1L-dependent manner. CSE1L overexpression increased nuclear levels of TAZ, whereas CSE1L silencing delayed its nuclear import. We also found via the in vitro coimmunoprecipitation experiments that TI-4 strengthened the interaction between CSE1L and importin α5 and blocked the binding of importin α5 to TAZ. WWTR1 silencing attenuated CSE1L-promoted colony formation, motility, and invasiveness of human lung cancer and glioblastoma cells. Conversely, CSE1L silencing blocked TAZ-promoted colony formation, motility, and invasiveness in human lung cancer and glioblastoma cells. In human cancer tissues, the expression level of CSE1L was found to correlate with nuclear levels of TAZ. These findings support that CSE1L promotes the nuclear accumulation of TAZ and enhances malignancy in cancer cells.

Mutations in the type 1 ryanodine receptor (RyR1), a Ca2+ release channel in skeletal muscle, hyperactivate the channel to cause malignant hyperthermia (MH) and are implicated in severe heat stroke. Dantrolene, the only approved drug for MH, has the disadvantages of having very poor water solubility and long plasma half-life. We show here that a novel RyR1-selective inhibitor, 6,7-(methylenedioxy)-1-octyl-4-quinolone-3-carboxylic acid (Compound 1, Cpd1), effectively prevents and treats MH and heat stroke in several mouse models relevant to MH. Cpd1 reduced resting intracellular Ca2+, inhibited halothane- and isoflurane-induced Ca2+ release, suppressed caffeine-induced contracture in skeletal muscle, reduced sarcolemmal cation influx, and prevented or reversed the fulminant MH crisis induced by isoflurane anesthesia and rescued animals from heat stroke caused by environmental heat stress. Notably, Cpd1 has great advantages of better water solubility and rapid clearance in vivo over dantrolene. Cpd1 has the potential to be a promising new candidate for effective treatment of patients carrying RyR1 mutations.

Nuclear receptors are ligand-inducible transcriptional factors that control multiple biological phenomena, including proliferation, differentiation, reproduction, metabolism, and the maintenance of homeostasis. Members of the nuclear receptor superfamily have marked structural and functional similarities, and their domain functionalities and regulatory mechanisms have been well studied. Various modulators of nuclear receptors, including agonists and antagonists, have been developed as tools for elucidating nuclear receptor functions and also as drug candidates or lead compounds. Many assay systems are currently available to evaluate the modulation of nuclear receptor functions, and are useful as screening tools in the discovery and development of new modulators. In this review, we cover the chemical screening methods for nuclear receptor modulators, focusing on assay methods and chemical libraries for screening. We include some recent examples of the discovery of nuclear receptor modulators.

We designed and synthesized aromatic polyamides with a diphenylacetylene backbone, α-DPA and β-DPA, bearing (S)-α- and (S)-β-methyl-substituted triethyleneglycol (TEG) side chains, respectively, an...

Transcriptional co-activator with PDZ-binding motif (TAZ) plays versatile roles in the regulation of cell proliferation and differentiation. TAZ activity changes in response to the cellular environment such as mechanic and nutritional stimuli, osmolarity, and hypoxia. To understand the physiological roles of TAZ, chemical compounds that activate TAZ in cells are useful as experimental reagents. Kaempferol, TM-25659, and ethacridine are reported as TAZ activators. However, as each TAZ activator has a distinct property in cellular functions, additional TAZ activators are awaiting. We screened for TAZ activators and previously reported IB008738 as a TAZ activator that promotes myogenesis in C2C12 cells. In this study, we have characterized IBS004735 that was obtained in the same screening. IBS004735 also promotes myogenesis in C2C12 cells, but is not similar to IBS008738 in the structure. IBS004735 activates TAZ via Akt and has no effect on TAZ phosphorylation, which is the well-described key modification to regulate TAZ activity. Thus, we introduce IBS004735 as a novel TAZ activator that regulates TAZ in a yet unidentified mechanism.

In eukaryotic cells, when exposed to certain types of stress including hypoxia, eIF2α is phosphorylated by several kinases including protein kinase R (PKR) and PKR-like endoplasmic reticulum kinase (PERK). Subsequently, protein translation is stopped and stress granules (SGs) are formed. Cancer cells form SGs under hypoxia. SGs accumulate apoptosis-related molecules and play anti-apoptotic roles. Thus, hypoxia-induced SG formation contributes to drug resistance in cancer cells. For this reason, inhibition of SG formation is expected to be beneficial in cancer therapy. To prove this concept, chemical reagents that inhibit SG formation are required as experimental tools. We searched for chemical compounds that suppress SG formation and identified that β-estradiol, progesterone, and stanolone (hereafter described as EPS) inhibit SG formation in human cervical cancer HeLa cells. As it turned out, EPS block PKR but not PERK, thus fail to suppress SG formation in most cancer cells, where SGs are formed via PERK. Nevertheless, in this study, we used HeLa cells as a model and demonstrated that EPS block hypoxia-induced SG formation in HeLa cells and consequently reduce drug resistance that HeLa cells acquire under hypoxia. Our findings support that inhibition of SG formation is a useful method to control cancers.

Novel liquid-crystalline N,N′-diarylsquaramides 1a and 1b were designed and synthesized, and their properties were elucidated. The squaramides exhibited thermotropic columnar liquid-crystalline phases at low temperature including room temperature. X-ray crystallographic analysis of methoxy derivative 1c showed the self-assembly of face-to-faced dimer through π-π interaction.

Here, aiming to adopt the phenyl–perfluorophenyl interaction to regulate molecular alignment and arrangement for crystal engineering, we examined and compared in detail the crystal structures of N,N′-diphenylurea compounds 1–6. We found that phenyl–perfluorophenyl interaction greatly influenced the intermolecular arrangement in the crystal, and we were able to prepare a cocrystal of 1 and 2, in which the molecules were alternately arranged under the control of the phenyl–perfluorophenyl interaction. This arrangement was driven by the asymmetric geometry of the hydrogen bonds in the cocrystal (1·2), in which 2, bearing two perfluorophenyl groups, worked as a better hydrogen bond donor. In contrast, NH connected to the phenyl group in 3 proved to be a better hydrogen bond donor due to the intramolecular resonance effect. N,N′-Dimethylated derivatives, 4–6, existed in cis-cis form in the crystal. Antiparallel carbonyl–carbonyl arrangements were observed in 4 and 6, while an unexpected carbonyl–perfluoropheny...

Methylations of specific lysine residues of histone proteins are catalyzed by histone methyltransferases (HMTs) and play key roles in the epigenetic control of gene expression. Several methods to detect N-e-methylation of the lysine residue have been established in order to evaluate the activity of HMTs, to develop inhibitors, and to identify substrates. However, they mostly employ specific antibodies or enzymes such as peptidases, and their reliability and reproducibility often depend on the quality of the protein reagents and the reaction conditions. Here, we describe a convenient method to detect N-e-monomethylation of the lysine residue through a simple chemical reaction. We focused on nucleophilic aromatic substitution reaction (SNAr reaction) between an aromatic electrophile and a primary or monomethylated amino group. Screening of various electrophiles indicated that 4-fluoro-2-nitroacetophenone (1g) has high selectivity for the N-e-monomethylated amino group of lysine. Furthermore, the reaction products of 1g with lysine and N-e-monomethylated lysine, 5g and 6g, respectively, show different absorption spectra, that is, the absorbance at 350 nm of 6g is 13 times larger than that of 5g. We show that these characteristic properties of 1g can be utilized for the selective detection of the methylation state of lysine residues in HMT substrate peptides, and for an assay of HMT activity.

N-Benzyl-N-(4-phenoxyphenyl)benzenesulfonamide derivatives were developed as a novel class of nonsteroidal glucocorticoid receptor (GR) modulators, which are promising drug candidates for treating immune-related disorders. Focusing on the similarity of the GR and progesterone receptor (PR) ligand-binding domain (LBD) structures, we adopted our recently developed PR antagonist 10 as a lead compound and synthesized a series of derivatives. We found that the N-(4-phenoxyphenyl)benzenesulfonamide skeleton serves as a versatile scaffold for GR antagonists. Among them, 4-cyano derivative 14m was the most potent, with an IC50 value of 1.43 μM for GR. This compound showed good selectivity for GR; it retained relatively weak antagonistic activity toward PR (IC50 for PR: 8.00 μM; 250-fold less potent than 10), but showed no activity toward AR, ERα or ERβ. Interestingly, the 4-amino derivative 15a exhibited transrepression activity toward NF-κB in addition to GR-antagonistic activity, whereas 14m did not. The structure-activity relationship for transrepression was different from that for GR-antagonistic activity. Computational docking simulations suggested that 15a might bind to the ligand-binding pocket of GR in a different manner from 14m. These findings open up new possibilities for developing novel nonsteroidal GR modulators with distinctive activity profiles.

For the first time, CO 2 -expanded bio-based liquids were reported as novel and sustainable solvents for biocatalysis. Herein, it was found that by expansion with CO 2 , 2-methyltetrahydrofuran (MeTHF), and other bio-based liquids, which were not favorable solvents for immobilized Candida antarctica lipase B (Novozym 435) catalyzed transesterification, were tuned into excellent reaction media. Especially, for the kinetic resolution of challenging bulky secondary substrates such as rac -1-adamantylethanol, the lipase displayed very high activity with excellent enantioselectivity ( E value > 200) in CO 2 -expanded MeTHF (MeTHF concentration 10% v/v, 6 MPa), whereas there was almost no activity observed in conventional organic solvents.

Functional studies indicate that essential cellular processes are controlled by Vitamin A derivatives. Among these the retinoic acid isoforms, all-trans- and 9-cis (9cRA), regulate the expression of various genes in both physiological and pathological conditions. Using several in vitro experimental models such as pancreatic β-cells, pre-adipocytes and breast cancer cells with different phenotypes, we demonstrated the capability of 9cRA to modulate myotrophin (Mtpn) and miR-375 expressions. The 9cRA effect in pancreatic β-cells line INS-1 832/13 point out a decreased expression of Mptn at both mRNA and protein levels associated to a concomitant increase of miR-375. We also studied the effect of this molecule on 3T3-L1 pre-adipocytes cells demonstrating a down-regulation of Mtpn and a dramatic increase of miR-375. Moreover, in the in vitro breast cancer model such as MDA-MB-231 and MCF-7 cells, 9cRA showed different effect on both Mtpn and miR-375 expression. In INS-1 832/13, 3T3-L1 pre-adipocytes and MCF-7 but not in MDA-MB-231, the effect of 9cRA on Mptn gene expression and its miR was under the control of RARs and RXRs receptors, as revealed by the exposure of these cell line to LE540 or HX603 receptor antagonists. In our findings 9cRA emerges has a hormone with a regulatory action on miR-375 that in most cases interfere with Mtpn expression.

Understanding and identifying the receptor subtype selectivity of a ligand is an important issue in the field of drug discovery. Using a combination of classical molecular mechanics and quantum mechanical calculations, this report assesses the receptor subtype selectivity for the human retinoid X receptor (hRXR) and retinoic acid receptor (hRAR) ligand‐binding domains (LBDs) complexed with retinoid ligands. The calculated energies show good correlation with the experimentally reported binding affinities. The technique proposed here is a promising method as it reveals the origin of the receptor subtype selectivity of selective ligands.

The progesterone receptor (PR) controls various physiological processes, including the female reproductive system, and nonsteroidal PR ligands are considered to be drug candidates for treatment of various diseases without significant adverse effects. Here, we designed and synthesized m-carborane-based secondary alcohols and investigated their PR-ligand activity. All the synthesized alcohols exhibited PR-antagonistic activity at subnanomolar concentration. Among them, alcohols having a small alkyl side chain and a 4-cyanophenyl group also exhibited PR-agonistic activity in a relatively high concentration range. Optical resolution of secondary alcohols having a methyl side chain was performed, and the PR-ligand activity and PR-binding affinity of the purified enantiomers were examined. The chirality of the secondary alcohol appears to have a more significant influence on PR-agonistic activity than on antagonistic activity.

The rapidly accelerated fibrosarcoma (Raf) kinase is canonically activated by growth factors that regulate multiple cellular processes. In this kinase cascade Raf activation ultimately results in extracellular regulated kinase 1/2 (Erk1/2) activation, which requires Ras binding to the Ras binding domain (RBD) of Raf. We recently reported that all-trans retinoic acid (atRA) rapidly (within minutes) activates Erk1/2 to modulate cell cycle progression in stem cells, which is mediated by cellular retinoic acid binding protein 1 (Crabp1). But how atRA-bound Crabp1 regulated Erk1/2 activity remained unclear. We now report Raf kinase as the direct target of atRA-Crabp1. Molecularly, Crabp1 acts as a novel atRA-inducible scaffold protein for Raf/Mek/Erk in cells without growth factor stimulation. However, Crabp1 can also compete with Ras for direct interaction with the RBD of Raf, thereby negatively modulating growth factor-stimulated Raf activation, which can be enhanced by atRA binding to Crabp1. NMR heteronuclear single quantum coherence (HSQC) analyses reveal the 6-strand β-sheet face of Crabp1 as its Raf-interaction surface. We identify a new atRA-mimicking and Crabp1-selective compound, C3, that can also elicit such an activity. This study uncovers a new signal crosstalk between endocrine (atRA-Crabp1) and growth factor (Ras-Raf) pathways, providing evidence for atRA-Crabp1 as a novel modulator of cell growth. The study also suggests a new therapeutic strategy by employing Crabp1-selective compounds to dampen growth factor stimulation while circumventing RAR-mediated retinoid toxicity.

Lithocholic acid (2) was identified as the second endogenous ligand of vitamin D receptor (VDR), though its binding affinity to VDR and its vitamin D activity are very weak compared to those of the active metabolite of vitamin D3, 1α,25-dihydroxyvitamin D3 (1). 3-Acylated lithocholic acids were reported to be slightly more potent than lithocholic acid (2) as VDR agonists. Here, aiming to develop more potent lithocholic acid derivatives, we synthesized several derivatives bearing a 3-sulfonate/carbonate or 3-amino/amide substituent, and examined their differentiation-inducing activity toward human promyelocytic leukemia HL-60 cells. Introduction of a nitrogen atom at the 3-position of lithocholic acid (2) decreased the activity, but compound 6 bearing a 3-methylsulfonate group showed more potent activity than lithocholic acid (2) or its acylated derivatives. The binding of 6 to VDR was confirmed by competitive binding assay and X-ray crystallographic analysis of the complex of VDR ligand-binding domain (LBD) with 6.

Combination therapy is often an effective strategy to treat cancer. In this study, we examined the growth-inhibitory effects of Am80 (tamibarotene), a specific retinoic acid receptor (RAR) α/β agonist, in combination with a histone deacetylase (HDAC) inhibitor, suberoylanilide hydroxamic acid (SAHA), or a DNA methyl transferase (DNMT) inhibitor, 5-aza-2'-deoxycytidine, on androgen receptor (AR)-positive and AR-negative prostate cancer cell lines (LNCaP and PC-3, respectively). We found that the combination therapy of SAHA and Am80 showed an enhanced growth-inhibitory effect on LNCaP cells. Further studies with various HDAC isotype-selective inhibitors showed that SAHA and KD5170 (a selective class I and II HDAC inhibitor) each increased the RARα protein level in LNCaP cells. Our results indicate that the target of the enhancing effect belongs to the Class IIb HDACs, especially HDAC6. Dual targeting of Class IIb HDAC and RARα may be a candidate therapeutic strategy for prostate cancer.

Alternately N-alkylated aromatic amides such as 1-3 bearing various side chains were designed and synthesized as novel helical foldamers. The CD spectra of oligomers with chiral side chains showed a positive Cotton effect, which indicates that these oligomers take helical conformations in solution. The CD intensity gradually increased with increasing chain length, and pentamer 3d showed remarkably strong CD signals in chloroform. The absorption maxima of the UV spectra were increasingly red shifted with increasing chain length, in contrast to the case of poly( p- N-alkylbenzamide)s. Structure optimization of the oligomers based on the crystal structure of 1a as the monomer unit supported the formation of helical structure with a large cavity and also suggested intramolecular hydrogen bond formation between secondary amides. The results of calculation were consistent with the observed spectroscopic features.

We report here development of N-(4-phenoxyphenyl)benzenesulfonamide derivatives as a novel class of nonsteroidal progesterone receptor (PR) antagonists. PR plays key roles in various physiological systems, including the female reproductive system, and PR antagonists are candidates for clinical treatment of multiple diseases, including uterine leiomyoma, endometriosis, breast cancer, and some psychiatric disorders. We found that the benzenesulfonanilide skeleton functions as a novel scaffold for PR antagonists, and we adopted 3-chlorobenzenesulfonyl derivative 20a as a lead compound for structural development. Among the synthesized compounds, 3-trifluoromethyl derivative 32 exhibited the most potent PR-antagonistic activity, with high binding affinity for PR and selectivity over androgen receptor (AR). It is structurally distinct from other nonsteroidal PR antagonists, including cyanopyrrole derivatives, and further modification is expected to afford novel selective PR modulators.

Canthin-5,6-dione is a common structure of the fluorescent natural products amarastelline A and nigakinone. Here, we synthesized various derivatives, and studied their fluorescence properties. The effects of substituent groups at the N 3 -, 4- and 10-positions were clarified. N 3 -Substitution influenced the solvent-dependent fluorescent change by modulating tautomerization between canthin-5,6-dione and the 5-hydroxy-6-one form. 10-Substitution also influenced the fluorescence, especially in aqueous solution, in combination with N 3 -substitution. Among the synthesized compounds, 5 showed an ‘OFF-ON-OFF’-type fluorescence change with increase of pH, and therefore served as a novel fluorescent sensor for a specific range of pH. Our findings suggest that canthin-5,6-dione should be useful as a fluorophore moiety for fluorescent labeling of biomolecules and for development of fluorescent probes and sensors.

We report here structural development of N-(4-phenoxyphenyl)benzamide derivatives as novel SPAK (STE20/SPS1-related proline/alanine-rich kinase) inhibitors. Abnormal activation of the signal cascade of with-no-lysine kinase (WNK) with OSR1 (oxidative stress-responsive kinase 1)/SPAK and NCC (NaCl cotransporter) results in characteristic salt-sensitive hypertension, and therefore inhibitors of the WNK-OSR1/SPAK-NCC cascade are candidates for antihypertensive drugs. Based on the structure of lead compound 2, we examined the SAR of N-(4-phenoxyphenyl)benzamide derivatives, and developed compound 20l as a potent SPAK inhibitor. Compounds 20l is a promising candidate for a new class of antihypertensive drugs.

First-generation nonsteroidal androgen receptor (AR) antagonists, such as flutamide (2a) and bicalutamide (3), are effective for most prostate cancer patients, but resistance often appears after several years due to the mutation of AR. Second-generation AR antagonists are effective against some of these castration-resistant prostate cancers, but their structural variety is still limited. In this study, we designed and synthesized 4-methyl-7-(N-alkyl-arylcarboxamido)coumarins as AR antagonist candidates and evaluated their growth-inhibitory activity toward androgen-dependent SC-3 cells. Coumarinamides with a secondary amide bond did not show inhibitory activity, but their N-methylated derivatives exhibited AR-antagonistic activity. Especially, 19b and 31b were more potent than the lead compound 7b, which was comparable to hydroxyflutamide (2b). Conformational analysis showed that the inactive coumarinamides with a secondary amide bond have an extended structure with a trans-amide bond, while the active N-methylated coumarinamides have a folded structure with a cis-amide bond, in which the two aromatic rings are placed face-to-face. Docking study suggested that this folded structure is important for binding to AR. Selected coumarinamide derivatives showed AR-antagonistic activity toward LNCaP cells with T877A AR, and they had weak progesterone receptor (PR)-antagonistic activity. The folded coumarinamide structure appears to be a unique pharmacophore, different from those of conventional AR antagonists.

Acute liver injury (ALI) is highly lethal acute liver failure caused by different etiologies. Transforming growth factor β (TGF-β) is a multifunctional cytokine and a well-recognized inducer of apoptotic and necrotic cell death in hepatocytes. Latent TGF-β is activated partly through proteolytic cleavage by a serine protease plasma kallikrein (PLK) between the R58 and L59 residues of its propeptide region. Recently, we developed a specific monoclonal antibody to detect the N-terminal side LAP degradation products ending at residue R58 (R58 LAP-DPs) that reflect PLK-dependent TGF-β activation. This study aimed to explore the potential roles of PLK-dependent TGF-β activation in the pathogenesis of ALI. We established a mouse ALI model via the injection of anti-Fas antibodies (Jo2) and observed increases in the TGF-β1 mRNA level, Smad3 phosphorylation, TUNEL-positive apoptotic hepatocytes and R58-positive cells in the liver tissues of Jo2-treated mice. The R58 LAP-DPs were observed in/around F4/80-positive macrophages, while macrophage depletion with clodronate liposomes partly alleviated the Jo2-induced liver injury. Blocking PLK-dependent TGF-β activation using either the serine proteinase inhibitor FOY305 or the selective PLK inhibitor PKSI-527 or blocking the TGF-β receptor-mediated signaling pathway using SB431542 significantly prevented Jo2-induced hepatic apoptosis and mortality. Furthermore, similar phenomena were observed in the mouse model of ALI with the administration of acetaminophen (APAP). In summary, R58 LAP-DPs reflecting PLK-dependent TGF-β activation may serve as a biomarker for ALI, and targeting PLK-dependent TGF-β activation has potential as a therapeutic strategy for ALI.

Herein, we report the rational design, synthesis and biological evaluation of conjugates consisting of the synthetic retinoid Am580 and biotin connected via a linker moiety. We found that the linking substructure between the retinoid part and the biotin part is critical for retaining the biological activity. Conjugate 4 with a shorter linker showed similar potency to endogenous retinoid ATRA ( 1 ) and the parent compound Am580 ( 2 ) for neural differentiation of mouse embryotic carcinoma P19 cells, and showed the same pattern of induction of gene expression. It is expected to be useful as a probe for investigations of retinoid function. The design rationale and structure-activity relationship of the linker moiety are expected to be helpful for developing biotin conjugates of other nuclear receptor ligands.

The rapidly accelerated fibrosarcoma (Raf) kinase is canonically activated by growth factors that regulate multiple cellular processes. In this kinase cascade Raf activation ultimately results in extracellular regulated kinase 1/2 (Erk1/2) activation, which requires Ras binding to the Ras binding domain (RBD) of Raf. We recently reported that all-trans retinoic acid (atRA) rapidly (within minutes) activates Erk1/2 to modulate cell cycle progression in stem cells, which is mediated by cellular retinoic acid binding protein 1 (Crabp1). But how atRA-bound Crabp1 regulated Erk1/2 activity remained unclear. We now report Raf kinase as the direct target of atRA-Crabp1. Molecularly, Crabp1 acts as a novel atRA-inducible scaffold protein for Raf/Mek/Erk in cells without growth factor stimulation. However, Crabp1 can also compete with Ras for direct interaction with the RBD of Raf, thereby negatively modulating growth factor-stimulated Raf activation, which can be enhanced by atRA binding to Crabp1. NMR heteronuclear single quantum coherence (HSQC) analyses reveal the 6-strand β-sheet face of Crabp1 as its Raf-interaction surface. We identify a new atRA-mimicking and Crabp1-selective compound, C3, that can also elicit such an activity. This study uncovers a new signal crosstalk between endocrine (atRA-Crabp1) and growth factor (Ras-Raf) pathways, providing evidence for atRA-Crabp1 as a novel modulator of cell growth. The study also suggests a new therapeutic strategy by employing Crabp1-selective compounds to dampen growth factor stimulation while circumventing RAR-mediated retinoid toxicity.

Significance Hepatocellular carcinoma (HCC) is a highly lethal cancer, partly because of its high rate of recurrence, which is caused by the presence of liver cancer stem cells (CSCs). Here, using a selective chemopreventive agent, acyclic retinoid (ACR), as a bioprobe, we identified MYCN, which is mostly recognized as an oncogene in neuroblastoma, as a therapeutic target of ACR for HCC through a selective deletion of MYCN+ liver CSCs. We also demonstrated that the expression of MYCN in HCC served as a prognostic biomarker and positively correlated with recurrence of de novo HCC after curative treatment. Our study highlighted MYCN as a biomarker and therapeutic target in drug discovery for screening chemopreventive agents against the recurrence of HCC., Hepatocellular carcinoma (HCC) is a highly lethal cancer that has a high rate of recurrence, in part because of cancer stem cell (CSC)-dependent field cancerization. Acyclic retinoid (ACR) is a synthetic vitamin A-like compound capable of preventing the recurrence of HCC. Here, we performed a genome-wide transcriptome screen and showed that ACR selectively suppressed the expression of MYCN, a member of the MYC family of basic helix–loop–helix–zipper transcription factors, in HCC cell cultures, animal models, and liver biopsies obtained from HCC patients. MYCN expression in human HCC was correlated positively with both CSC and Wnt/β-catenin signaling markers but negatively with mature hepatocyte markers. Functional analysis showed repressed cell-cycle progression, proliferation, and colony formation, activated caspase-8, and induced cell death in HCC cells following silencing of MYCN expression. High-content single-cell imaging analysis and flow cytometric analysis identified a MYCN+ CSC subpopulation in the heterogeneous HCC cell cultures and showed that these cells were selectively killed by ACR. Particularly, EpCAM+ cells isolated using a cell-sorting system showed increased MYCN expression and sensitivity to ACR compared with EpCAM− cells. In a long-term (>10 y) follow-up study of 102 patients with HCC, MYCN was expressed at higher levels in the HCC tumor region than in nontumor regions, and there was a positive correlation between MYCN expression and recurrence of de novo HCC but not metastatic HCC after curative treatment. In summary, these results suggest that MYCN serves as a prognostic biomarker and therapeutic target of ACR for liver CSCs in de novo HCC.

Congenital nephrogenic diabetes insipidus (NDI) is characterized by the inability of the kidney to concentrate urine. Congenital NDI is mainly caused by loss-of-function mutations in the vasopressin type 2 receptor (V2R), leading to impaired aquaporin-2 (AQP2) water channel activity. So far, treatment options of congenital NDI either by rescuing mutant V2R with chemical chaperones or by elevating cyclic adenosine monophosphate (cAMP) levels have failed to yield effective therapies. Here we show that inhibition of A-kinase anchoring proteins (AKAPs) binding to PKA increases PKA activity and activates AQP2 channels in cortical collecting duct cells. In vivo, the low molecular weight compound 3,3′-diamino-4,4′-dihydroxydiphenylmethane (FMP-API-1) and its derivatives increase AQP2 activity to the same extent as vasopressin, and increase urine osmolality in the context of V2R inhibition. We therefore suggest that FMP-API-1 may constitute a promising lead compound for the treatment of congenital NDI caused by V2R mutations., Patients suffering from congenital nephrogenic diabetes insipidus (NDI) fail to concentrate urine due to mutations in vasopressin type 2 receptor (V2R). Here Ando et al. show that agents disrupting the interaction between PKA and AKAPs restore aquaporin-2 activity downstream of V2R, offering a therapeutic approach for the treatment of NDI.