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The human P2Y2 receptor (hP2Y2R) is a G-protein-coupled receptor that shows promise as a therapeutic target for many important conditions, including for antimetastatic cancer and more recently for idiopathic pulmonary fibrosis. As such, there is a need for new hP2Y2R antagonists and molecular probes to study this receptor. Herein, we report the development of a new series of non-nucleotide hP2Y2R antagonists, based on the known, non-nucleotide hP2Y2R antagonist AR-C118925 (1), leading to the discovery of a series of fluorescent ligands containing different linkers and fluorophores. One of these conjugates, 98, displayed micromolar affinity for hP2Y2R (pKd = 6.32 ± 0.10, n = 17) in a bioluminescence-energy-transfer (BRET) assay. Confocal microscopy with this ligand revealed displaceable membrane labeling of astrocytoma cells expressing untagged hP2Y2R. These properties make 98 one of the first tools for studying hP2Y2R distribution and organization. [ABSTRACT FROM AUTHOR]

A series of novel, highly potent, selective inhibitors targeting both CDK4/9 and HDAC1 have been designed and synthesized. N1-(4-((7-Cyclopentyl-6-(dimethylcarbamoyl)-7H-pyrrolo[2,3-d] pyrimidin-2-yl)amino)phenyl)-N8-hydroxyoctanediamide (6e) was discovered. The lead compound 6e with excellent CDK4/9 and HDAC1 inhibitory activity of IC50 = 8.8, 12, and 2.2 nM, respectively, can effectively induce apoptosis of cancer cell lines. The kinase profiling of compound 6e showed excellent selectivity and specificity. Compound 6e induces G2/M arrest in high concentration and G0/G1 arrest in low concentration to prevent the proliferation and differentiation of cancer cells. Mice bared-breast cancer treated with 6e showed significant antitumor efficacy. The insight into mechanisms of 6e indicated that it could induce cancer cell death via cell apoptosis based on CDK4/9 and HDAC1 repression and phosphorylation of p53. Our data demonstrated the novel compound 6e could be a promising drug candidate for cancer therapy. [ABSTRACT FROM AUTHOR]

Two series of novel benzenesulfonamide derivatives were synthesized and evaluated for their human carbonic anhydrase (CA, EC 4.2.1.1) inhibitory activity against four isoforms, hCA I, hCA II, hCA VII, and hCA IX. It was found that compounds of both series showed low to medium nanomolar inhibitory potential against all isoforms. Some of these derivatives displayed selective inhibition against the epileptogenesis related isoforms hCA II and VII, within the nanomolar range. These potent hCA II and VII inhibitors were evaluated as anticonvulsant agents against MES and sc-PTZ induced convulsions. These sulfonamides effectively abolished induced seizures in both models. Furthermore, time dependent seizure protection capability of the most potent compound was also evaluated. A long duration of action was displayed, with efficacy up to 6 h after drug administration. The compound appeared as an orally active anticonvulsant agent without showing neurotoxicity in a rotarod test, a nontoxic chemical profile being observed in subacute toxicity study. [ABSTRACT FROM AUTHOR]

The cyclic depsipeptide, teixobactin, kills a number of Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), and Mycobacterium tuberculosis without detectable resistance. To date, teixobactin is the only molecule in its class that has shown in vivo antibacterial efficacy. In this work, we designed and synthesized 10 new in vivo ready teixobactin analogues. These analogues showed highly potent antibacterial activities against Staphylococcus aureus, MRSA, and vancomycin-resistant enterococci (VRE) in vitro. One analogue, d-Arg4-Leu10-teixobactin, 2, was found to be noncytotoxic in vitro and in vivo. Moreover, topical instillation of peptide 2 in a mouse model of S. aureus keratitis decreased the bacterial bioburden (>99.0% reduction) and corneal edema significantly as compared to untreated mouse corneas. Collectively, our results have established the high therapeutic potential of a teixobactin analogue in attenuating bacterial infections and associated severities in vivo. [ABSTRACT FROM AUTHOR]

In this paper, 26 natural polymyxin components and a new derivative S2 were synthesized, and their differences in efficacy and toxicity have been investigated. Almost all of the synthesized components showed strong activity against both susceptible and resistant strains of E. coli, K. pneumoniae, P. aeruginosa, and A. baumannii. The toxicities were obviously different between the components. Only some of the components were tested for toxicity in vivo. Compounds E2, E2-Val, A2, M2, D2, and S2 showed obviously lower renal cytotoxicity and acute toxicity than polymyxins B and E. The in vivo nephrotoxicity of E2, M2, and S2 was similar to that of polymyxin E. Compound S2, with four positive charges, was especially interesting as it possessed both increased efficacy and decreased toxicity. The SAR and toxicity studies indicated that further structural modification could concentrate on polymyxin S. The results also indicated that S2 could be a new drug candidate. [ABSTRACT FROM AUTHOR]

A group of glutathione S-transferase π (GSTπ) activatable O²-(sulfonylethyl derived) diazeniumdiolates 5-12 were designed and synthesized. These compounds could be activated by GSTπ to initiate the β-elimination reaction, liberating an active vinyl sulfone-based GSH derivative and a diazeniumdiolate anion which subsequently releases NO in situ. The most active compound 6 released relatively high levels of NO and inhibited proliferation of melanoma B16 cells, superior to a diazeniumdiolate-based anticancer agent JS-K (1). Importantly, 6 had 8-fold less inhibitory activity against normal epithelial JB6 Cl 30-7b cells. The inhibitory activity of 6 could be diminished by an NO scavenger or GSTπ inhibitor. Furthermore, 6 induced nitration of mitochondrial tyrosine in B16 cells and inoculated B16 tumors in mice, which might be responsible for oxidation of protein leading to tumor suppression. Finally, 6 significantly retarded the B16 cells growth in a mouse xenograft model. These findings suggest that 6 may have a potential to treat melanoma. [ABSTRACT FROM AUTHOR]

Na,K-ATPase α4 is a testis-specific plasma membrane Na+ and K+ transporter expressed in sperm flagellum. Deletion of Na,K-ATPase α4 in male mice results in complete infertility, making it an attractive target for male contraception. Na,K-ATPase α4 is characterized by a high affinity for the cardiac glycoside ouabain. With the goal of discovering selective inhibitors of the Na,K-ATPase α4 and of sperm function, ouabain derivatives were modified at the glycone (C3) and the lactone (C17) domains. Ouabagenin analogue 25, carrying a benzyltriazole moiety at C17, is a picomolar inhibitor of Na,K-ATPase α4, with an outstanding α4 isoform selectivity profile. Moreover, compound 25 decreased sperm motility in vitro and in vivo and affected sperm membrane potential, intracellular Ca2+, pH, and hypermotility. These results proved that the new ouabagenin triazole analogue is an effective and selective inhibitor of Na,K-ATPase α4 and sperm function. [ABSTRACT FROM AUTHOR]

Three rationally designed pyrrolobenzodiazepine (PBD) drug-linkers have been synthesized via intermediate 19 for use in antibody-drug conjugates (ADCs). They lack a cleavable trigger in the linker and consist of a maleimide for cysteine antibody conjugation, a hydrophilic spacer, and either an alkyne (6), triazole (7), or piperazine (8) link to the PBD. In vitro IC50 values were 11-48 ng/mL in HER2 3+ SK-BR-3 and KPL-4 (7 inactive) for the anti-HER2 ADCs (HER2 0 MCF7, all inactive) and 0.10-1.73 µg/mL (7 inactive) in CD22 3+ BJAB and WSU-DLCL2 for anti-CD22 ADCs (CD22 0 Jurkat, all inactive at low doses). In vivo antitumor efficacy for the anti-HER2 ADCs in Founder 5 was observed with tumor stasis at 0.5-1 mg/kg, 1 mg/kg, and 3-6 mg/kg for 6, 8, and 7, respectively. Tumor stasis at 2 mg/kg was observed for anti-CD22 6 in WSU-DLCL2. In summary, noncleavable PBD-ADCs exhibit potent activity, particularly in HER2 models. [ABSTRACT FROM AUTHOR]

The highly stereocontrolled de novo synthesis of l-NBDNJ (the unnatural enantiomer of the iminosugar drug Miglustat) and a preliminary evaluation of its chaperoning potential are herein reported. l-NBDNJ is able to enhance lysosomal α-glucosidase levels in Pompe disease fibroblasts, either when administered singularly or when coincubated with the recombinant human α-glucosidase. In addition, differently from its d-enantiomer, l-NBDNJ does not act as a glycosidase inhibitor. [ABSTRACT FROM AUTHOR]

Following our findings on the anti-human immunodeficiency virus (HIV) activity of acyclovir (ACV) phosphate prodrugs, we herein report the ProTide approach applied to a series of acyclic nucleosides aimed at the identification of novel and selective antiviral, in particular anti-HIV agents. Acyclic nucleoside analogues used in this study were identified through a virtual screening using HIV-reverse transcriptase (RT), adenylate/guanylate kinase, and human DNA polymerase γ. A total of 39 new phosphate prodrugs were synthesized and evaluated against HIV-1 (in vitro and ex vivo human tonsillar tissue system) and human herpes viruses. Several ProTide compounds showed substantial potency against HIV-1 at low micromolar range while the parent nucleosides were not effective. Also, pronounced inhibition of herpesvirus replication was observed. A carboxypeptidase-mediated hydrolysis study was performed for a selection of compounds to assess the formation of putative metabolites and support the biological activity observed. [ABSTRACT FROM AUTHOR]

Fatty acyl analogues of muramyldipeptide (MDP) (abbreviated N-L18 norAbuGMDP, N-B30 norAbuGMDP, norAbuMDP-Lys(L18), norAbuMDP-Lys(B30), norAbuGMDP-Lys(L18), norAbuGMDP-Lys(B30), B30 norAbuMDP, L18 norAbuMDP) are designed and synthesized comprising the normuramyl-l-α-aminobutanoyl (norAbu) structural moiety. All new analogues show depressed pyrogenicity in both free (micellar) state and in liposomal formulations when tested in rabbits in vivo (sc and iv application). New analogues are also shown to be selective activators of NOD2 and NLRP3 (inflammasome) in vitro but not NOD1. Potencies of NOD2 and NLRP3 stimulation are found comparable with free MDP and other positive controls. Analogues are also demonstrated to be effective in stimulating cellular proliferation when the sera from mice are injected sc with individual liposome-loaded analogues, causing proliferation of bone marrow-derived GM-progenitors cells. Importantly, vaccination nanoparticles prepared from metallochelation liposomes, His-tagged antigen rOspA from Borrelia burgdorferi, and lipophilic analogue norAbuMDP-Lys(B30) as adjuvant, are shown to provoke OspA-specific antibody responses with a strong Th1-bias (dominance of IgG2a response). In contrast, the adjuvant effects of Alum or parent MDP show a strong Th2-bias (dominance of IgG1 response). [ABSTRACT FROM AUTHOR]

With the development of ever-expanding synthetic methodologies, a medicinal chemist's toolkit continues to swell. However, with finite time and resources as well as a growing understanding of our field's environment impact, it is critical to refine what can be made to what should be made. This review seeks to highlight multiple cheminformatic approaches in drug discovery that can influence and triage design and execution impacting the likelihood of rapidly generating high-value molecules in a more sustainable manner. This strategy gives chemists the tools to design and refine vast libraries, stress "druglikeness", and rapidly identify SAR trends. Project success, i.e., identification of a clinical candidate, is then reached faster with fewer molecules with the farther-reaching ramification of using fewer resources and generating less waste, thereby helping "green" our field. [ABSTRACT FROM AUTHOR]

Dysfunctional signaling of the PI3K/AKT/mTOR pathway in cancer and its crucial role in cell growth and survival have made it a much desired target for cancer therapeutics. A series of dimorpholine substituted thienopyrimidine derivatives had been prepared and evaluated in vitro and in vivo. Among them, compound 14o was identified as a dual Class I PI3K and mTOR kinase inhibitor, which had an approximately 8-fold improvement in mTOR inhibition relative to the class I PI3K inhibitor 1 (pictilisib, GDC-0941). Western blot analysis confirmed the 14o mechanistic modulation of the cellular PI3K/AKT/mTOR pathway through inhibiting phosphorylation of both AKT and S6 in human cancer cell lines. In addition, 14o demonstrated significant efficacy in SKOV-3 and U87MG tumor xenograft models without causing significant weight loss and toxicity. [ABSTRACT FROM AUTHOR]

Sphingosine 1-phosphate (S1P) is a pleiotropic signaling molecule that interacts with its five G-protein coupled receptors (S1P1-5) to regulate cell growth and survival and has been implicated in a variety of diseases including cancer and sickle cell disease. As the key mediators in the synthesis of S1P, sphingosine kinase (SphK) isoforms 1 and 2 have attracted attention as viable targets for pharmaceutical inhibition. In this article, we describe the design, synthesis, and biological evaluation of aminothiazole-based guanidine inhibitors of SphK. Surprisingly, combining features of reported SphK1 inhibitors generated SphK1/2 dual inhibitor 20l (SLC4011540) (hSphK1 K i = 120 nM, hSphK2 K i = 90 nM) and SphK2 inhibitor 20dd (SLC4101431) (K i = 90 nM, 100-fold SphK2 selectivity). These compounds effectively decrease S1P levels in vitro. In vivo administration of 20dd validated that inhibition of SphK2 increases blood S1P levels. [ABSTRACT FROM AUTHOR]

Members of the BET family of bromodomain containing proteins have been identified as potential targets for blocking proliferation in a variety of cancer cell lines. A two-dimensional NMR fragment screen for binders to the bromodomains of BRD4 identified a phenylpyridazinone fragment with a weak binding affinity (1, K i = 160 μM). SAR investigation of fragment 1, aided by X-ray structure-based design, enabled the synthesis of potent pyridone and macrocyclic pyridone inhibitors exhibiting single digit nanomolar potency in both biochemical and cell based assays. Advanced analogs in these series exhibited high oral exposures in rodent PK studies and demonstrated significant tumor growth inhibition efficacy in mouse flank xenograft models. [ABSTRACT FROM AUTHOR]

Previous structure-activity studies on the neoclerodane diterpenoid salvinorin A have demonstrated the importance of the acetoxy functionality on the A-ring in its activity as a κ-opioid receptor agonist. Few studies have focused on understanding the role of conformation in these interactions. Herein we describe the synthesis and evaluation of both flexible and conformationally restricted compounds derived from salvinorin A. One such compound, spirobutyrolactone 14, was synthesized in a single step from salvinorin B and had similar potency and selectivity to salvinorin A (EC50 = 0.6 ± 0.2 nM at κ; >10000 nM at μ and Δ). Microsomal stability studies demonstrated that 14 was more metabolically resistant than salvinorin A. Evaluation of analgesic and anti-inflammatory properties revealed similar in vivo effects between 14 and salvinorin A. To our knowledge, this study represents the first example of bioisosteric replacement of an acetate group by a spirobutyrolactone to produce a metabolically resistant derivative. [ABSTRACT FROM AUTHOR]

There is an urgent unmet medical need for novel antibiotics that are effective against a broad range of bacterial species, especially multidrug resistant ones. Tetrahydropyran-based inhibitors of bacterial type II topoisomerases (DNA gyrase and topoisomerase IV) display potent activity against Gram-positive pathogens and no target-mediated cross-resistance with fluoroquinolones. We report our research efforts aimed at expanding the antibacterial spectrum of this class of molecules toward difficult-to-treat Gram-negative pathogens. Physicochemical properties (polarity and basicity) were considered to guide the design process. Dibasic tetrahydropyran-based compounds such as 6 and 21 are potent inhibitors of both DNA gyrase and topoisomerase IV, displaying antibacterial activities against Gram-positive and Gram-negative pathogens (Staphylococcus aureus, Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii). Compounds 6 and 21 are efficacious in clinically relevant murine infection models. [ABSTRACT FROM AUTHOR]

A high-throughput screen (HTS) was undertaken against the respiratory chain dehydrogenase component, NADH:menaquinone oxidoreductase (Ndh) of Mycobacterium tuberculosis (Mtb). The 11000 compounds were selected for the HTS based on the known phenothiazine Ndh inhibitors, trifluoperazine and thioridazine. Combined HTS (11000 compounds) and in-house screening of a limited number of quinolones (50 compounds) identified 100 hits and four distinct chemotypes, the most promising of which contained the quinolone core. Subsequent Mtb screening of the complete in-house quinolone library (350 compounds) identified a further 90 hits across three quinolone subtemplates. Quinolones containing the amine-based side chain were selected as the pharmacophore for further modification, resulting in metabolically stable quinolones effective against multi drug resistant (MDR) Mtb. The lead compound, 42a (MTC420), displays acceptable antituberculosis activity (Mtb IC50 = 525 nM, Mtb Wayne IC50 = 76 nM, and MDR Mtb patient isolates IC50 = 140 nM) and favorable pharmacokinetic and toxicological profiles. [ABSTRACT FROM AUTHOR]

Pharmacological inhibition of NLRP3 inflammasome activation may offer a new option in the treatment of inflammatory bowel disease. In this work, we report the design, synthesis, and biological screening of a series of acrylate derivatives as NLRP3 inhibitors. The in vitro determination of reactivity, cytotoxicity, NLRP3 ATPase inhibition, and antipyroptotic properties allowed the selection of 11 (INF39), a nontoxic, irreversible NLRP3 inhibitor able to decrease interleukin-1β release from macrophages. Bioluminescence resonance energy transfer experiments proved that this compound was able to directly interfere with NLRP3 activation in cells. In vivo studies confirmed the ability of the selected lead to alleviate the effects of colitis induced by 2,4-dinitrobenzenesulfonic acid in rats after oral administration. [ABSTRACT FROM AUTHOR]

In the present work, a series of structurally novel benzocyclobutene derivatives were identified as general anesthetics through the loss of righting reflex (LORR) experiment on mice. Our initial efforts found compound 1a with a fused four-membered ring on the 2,3-position of the phenol ring could significantly improve the safety profile. Further SAR study revealed that small hydrogen bond acceptor (HBA) groups are optimal for good ED50 along with much broader therapeutic windows, such as compounds 16b and 17. Present work demonstrates the superiority of this novel benzocyclobutene scaffold. [ABSTRACT FROM AUTHOR]

A novel series of optically active 2,6-disubstituted alkylphenols with improved anesthetic profiles compared to widely used propofol were synthesized. The incorporation of the cyclopropyl group not only increased the steric effect but also introduced stereoselective effects over their anesthetic properties. Compounds 1, 2, and 6 were selected as potential candidates for further preclinical development including studies of their water-soluble prodrugs. Clinical studies of candidate compound 6 (Haisco HSK3486) as a general anesthetic are being performed in Australia and China. [ABSTRACT FROM AUTHOR]

Standard antibiotic-based strategies for the treatment of Clostridium difficile infections disrupt indigenous microbiota and commonly fail to eradicate bacterial spores, two key factors that allow recurrence of infection. As an alternative approach to controlling C. difficile infection, a series of bile acid derivatives have been prepared that inhibit taurocholate-induced spore germination. These analogues have been evaluated in a highly virulent NAP1 strain using optical density and phase-contrast microscopy assays. Heterocycle substitutions at C24 were well-tolerated and several tetrazole-containing derivatives were highly potent inhibitors in both assays, with complete inhibition of spore germination observed at 10-25 μM. To limit intestinal absorption, C7-sulfated analogues designed to avoid active and passive transport pathways were prepared. One of these derivatives, compound 21b, was found to be a potent inhibitor of C. difficile spore germination and poorly permeable in a Caco-2 model of intestinal epithelial absorption, suggesting that it is likely to be gut-restricted. [ABSTRACT FROM AUTHOR]

We synthesized 1 (San78-130), a reversible version of L-783277, as a selective and potent ALK1 inhibitor. Our study showed that 1 possesses great kinase selectivity against a panel of 342 kinases and more potent activity against ALK1 than L-783277. Among the six ALK isotypes (ALK1-6), ALK1 is most significantly inhibited by compound 1. Compound 1 suppresses the BMP9-induced Smad1/5 pathway by mainly inhibiting ALK1 in C2C12 cells. Our molecular dynamics simulations suggest that H-bonding interaction between the C-4′ hydroxyl group of 1 and Arg334 of ALK1 substantially contributes to the ALK1 inhibition. To the best of our knowledge, 1 is the first selective ALK1 inhibitor. Furthermore, compound 1 promoted angiogenesis in both endothelial tube formation and microfluidic chip based 3D angiogenesis assays, suggesting that 1 could be a lead compound for therapeutic angiogenesis agents. Our study may provide an insight into designing selective and potent inhibitors against ALK1. [ABSTRACT FROM AUTHOR]

A series of pyrazolo(dihydro)pyridines was synthesized and evaluated for antileishmanial efficacy against experimental visceral leishmaniasis (VL). Among all compounds, 6d and 6j exhibited better activity than miltefosine against intracellular amastigotes. Compound 6j (50 mg/kg/day) was further studied against Leishmania donovani/BALB/c mice via the intraperitoneal route for 5 days and displayed >91 and >93% clearance of splenic and liver parasitic burden, respectively. Combination treatment of 6j with a subcurative dose of miltefosine (5 mg/kg) in BALB/c mice almost completely ameliorated the disease (>97% inhibition) by augmenting nitric oxide generation and shifting the immune response toward Th1. Furthermore, investigating the effect of 6j on Leishmania promastigotes revealed that it induced molecular events, such as a loss in mitochondrial membrane potential, externalization of phosphatidylserine, and DNA fragmentation, that ultimately resulted in the programmed cell death of the parasite. These results along with pharmacokinetic studies suggest that 6j could be a promising lead for treating VL as an adjunct therapy with miltefosine. [ABSTRACT FROM AUTHOR]

Nalfurafine, a κ-selective opioid receptor agonist, unexpectedly showed a selective antagonist activity toward the orexin 1 receptor (OX1R) (Ki = 250 nM). Modification of the 17-amino side chain of the opioid ligand to an arylsulfonyl group and the 6-furan acrylamide chain to 2-pyridyl acrylamide led to compound 71 with improvement of the antagonist activity (OX1R, Ki = 1.36 nM; OX2R, not active) without any detectable affinity for the opioid receptor. The dihydrosulfate salt of 71, freely soluble in water, attenuated the physical dependence of morphine. Furthermore, all of the active nalfurafine derivatives in this study had almost no activity for OX2R, which led to high OX1R selectivity. These results suggest that nalfurafine derivatives could be a useful series of lead compounds to develop highly selective OX1R antagonists. [ABSTRACT FROM AUTHOR]

Natural depsipeptide vinylamycin was reported to be an antibiotic previously. Herein we report vinylamycin to be active against K562 leukemia cells (IC50 = 4.86 μM) and be unstable in plasma (t1/2 = 0.54 h). A total of 24 vinylamycin analogues with modification of the OH group and chiral centers were generated via a combinatorial approach. The lead compound 1a was subsequently characterized as having the following: no antimicrobial activity, significantly higher plasma stability (t1/2 = 14.3 h), improved activity against K562 leukemia cells (IC50 = 0.64 μM), and up to 75% cell inhibition without significant toxicities in K562 cells xenograft zebrafish model. Furthermore, compound 1a maintained its activity against the breast cancer cell line MCF-7 under hypoxic conditions. In comparison, the activity of gemcitabine in the same hypoxic in vitro model of MCF-7 cells was 15-fold lower. Therefore, the present results demonstrate that 1a has great potential as an anticancer agent. [ABSTRACT FROM AUTHOR]

We report the synthesis of a series of hybrid compounds incorporating 6- and 7-substituted coumarins (carbonic anhydrase, CA inhibitors) derivatized with clinically used NSAIDs (indomethacin, sulindac, ketoprofen, ibuprofen, diclofenac, ketorolac, etc., cyclooxygenase inhibitors) as agents for the management of rheumatoid arthritis (RA). Most compounds were effective in inhibiting the RA overexpressed hCA IX and XII, with KI values in the low nanomolar-subnanomolar ranges. The antihyperalgesic activity of such compounds was assessed by means of the paw-pressure and incapacitance tests using an in vivo RA model. Among all tested compounds, the 7-coumarine hybrid with ibuprofen showed potent and persistent antihyperalgesic effect up to 60 min after administration. [ABSTRACT FROM AUTHOR]

We report the design, synthesis, and structure-activity relationships of novel dual-target compounds with antagonist/inverse agonist activity at cannabinoid receptor type 1 (CB1R) and inhibitory effect on inducible nitric oxide synthase (iNOS). A series of 3,4-diarylpyrazolinecarboximidamides were synthesized and evaluated in CB1 receptor (CB1R) binding assays and iNOS activity assays. The novel compounds, designed to have limited brain penetrance, elicited potent in vitro CB1R antagonist activities and iNOS inhibitory activities. Some key compounds displayed high CB1R binding affinities. Compound 7 demonstrated potent in vivo pharmacological activities such as reduction of food intake mediated by the antagonism of the CB1Rs and antifibrotic effect in the animal models of fibrosis mediated by iNOS inhibition and CB1R antagonism. [ABSTRACT FROM AUTHOR]

A previous publication from this lab (Patrick, et al.) explored the antitrypanosomal activities of novel derivatives of 2-(2-benzamido)ethyl-4-phenylthiazole (1), which had been identified as a hit against Trypanosoma brucei, the causative agent of human African trypanosomiasis. While a number of these compounds, particularly the urea analogues, were quite potent, these molecules as a whole exhibited poor metabolic stability. The present work describes the synthesis of 65 new analogues arising from medicinal chemistry optimization at different sites on the molecule. The most promising compounds were the urea derivatives of 2-aryl-benzothiazol-5-amines. One such analogue, (S)-2-(3,4-difluorophenyl)-5-(3-fluoro-N-pyrrolidylamido)benzothiazole (57) was chosen for in vivo efficacy studies based upon in vitro activity, metabolic stability, and brain penetration. This compound attained 5/5 cures in murine models of both early and late stage human African trypanosomiasis, representing a new lead for the development of drugs to combat this neglected disease. [ABSTRACT FROM AUTHOR]

Cyclophilin inhibition has been a target for the treatment of hepatitis C and other diseases, but the generation of potent, drug-like molecules through chemical synthesis has been challenging. In this study, a set of macrocyclic cyclophilin inhibitors was synthesized based on the core structure of the natural product sanglifehrin A. Initial compound optimization identified the valine-m-tyrosine-piperazic acid tripeptide (Val-m-Tyr-Pip) in the sanglifehrin core, stereocenters at C14 and C15, and the hydroxyl group of the m-tyrosine (m-Tyr) residue as key contributors to compound potency. Replacing the C18-C21 diene unit of sanglifehrin with a styryl group led to potent compounds that displayed a novel binding mode in which the styrene moiety engaged in a π-stacking interaction with Arg55 of cyclophilin A (Cyp A), and the m-Tyr residue was displaced into solvent. This observation allowed further simplifications of the scaffold to generate new lead compounds in the search for orally bioavailable cyclophilin inhibitors. [ABSTRACT FROM AUTHOR]

Natural killer cells are able to directly lyse tumor cells, thereby participating in the immune surveillance against cancer. Unfortunately, many cancer cells use immune evasion strategies to avoid their eradication by the immune system. A prominent escape strategy of malignant cells is to camouflage themselves with Siglec-7 ligands, thereby recruiting the inhibitory receptor Siglec-7 expressed on the NK cell surface which subsequently inhibits NK-cell-mediated lysis. Here we describe the synthesis and evaluation of the first, high-affinity low molecular weight Siglec-7 ligands to interfere with cancer cell immune evasion. The compounds are Sialic acid derivatives and bind with low micromolar Kd values to Siglec-7. They display up to a 5000-fold enhanced affinity over the unmodified sialic acid scaffold αMe Neu5Ac, the smallest known natural Siglec-7 ligand. Our results provide a novel immuno-oncology strategy employing natural immunity in the fight against cancers, in particular blocking Siglec-7 with low molecular weight compounds. [ABSTRACT FROM AUTHOR]

Multidrug resistance is a major obstacle to successful chemotherapy for leukemia. In this study, a series of nitric oxide (NO)-releasing bifendate derivatives (7a-n) were synthesized. Biological evaluation indicated that the most active compound (7a) produced relatively high levels of NO and significantly inhibited the proliferation of drug-resistant K562/A02 cells in vitro and in vivo. In addition, 7a induced the mitochondrial tyrosine nitration and the intracellular accumulation of rhodamine 123 by inhibiting P-gp activity in K562/A02 cells. Furthermore, 7a remarkably down-regulated AKT, NF-κB, and ERK activation and HIF-1α expression in K562/A02 cells, which are associated with the tumor cell proliferation and drug resistance. Notably, the antitumor effects were dramatically attenuated by an NO scavenger or elimination of the NO-releasing capability of 7a, indicating that NO produced by 7a contributed to, at least partly, its cytotoxicity against drug-resistant K562/A02 cells. Overall, 7a may be a potential agent against drug-resistant myelogenous leukemia. [ABSTRACT FROM AUTHOR]

Metadynamics (META-D) is emerging as a powerful method for the computation of the multidimensional free-energy surface (FES) describing the protein-ligand binding process. Herein, the FES of unbinding of the antagonist N-(3α-hydroxy-5β-cholan-24-oyl)-L-β-homotryptophan (UniPR129) from its EphA2 receptor was reconstructed by META-D simulations. The characterization of the free-energy minima identified on this FES proposes a binding mode fully consistent with previously reported and new structure-activity relationship data. To validate this binding mode, new N-(3α-hydroxy-5β-cholan-24-oyl)-L-β-homotryptophan derivatives were designed, synthesized, and tested for their ability to displace ephrin-A1 from the EphA2 receptor. Among them, two antagonists, namely compounds 21 and 22, displayed high affinity versus the EphA2 receptor and resulted endowed with better physicochemical and pharmacokinetic properties than the parent compound. These findings highlight the importance of free-energy calculations in drug design, confirming that META-D simulations can be used to successfully design novel bioactive compounds. [ABSTRACT FROM AUTHOR]

The development of small molecule inhibitors targeting GPVI has promising therapeutic role, as they inhibit arterial thrombosis with limited risk of bleeding. Among the compounds showing in vivo antithrombotic activity, the most active compound 6b (ED50 = 28.36 μmol/kg po in mice) showed improved inhibition for collagen (IC50 = 6.7 μM), CRP-XL (IC50 = 53.5 μM), and convulxin (CVX) (IC50 = 5.7 μM) mediated platelet aggregation as compared to losartan (LOS) (collagen, IC50 = 10.4 μM; CRP-XL, IC50 = 158 μM; CVX, IC50 = 11 μM) than any of its enantiomers S (6c) (collagen, IC50 = 25.3 μM; CRP-XL, IC50 = 181.4 μM; CVX, IC50 = 9 μM) and R (6d) (collagen, IC50 = 126.3 μM; CRP-XL, IC50 > 500 μM; CVX, IC50 = 86.8 μM). Compound 6b also inhibited platelet P-selectin expression and thus may diminish atherosclerosis. The molecular interactions of both enantiomers 6c and 6d at the GPVI receptor have been explained through docking studies. [ABSTRACT FROM AUTHOR]

On the basis of a previously discovered anti-αVβ3 integrin peptidomimetic (c(AmpRGD)) and the clinically approved antiangiogenic kinase inhibitor sunitinib, three novel dual conjugates were synthesized (compounds 1-3), featuring the covalent and robust linkage between these two active modules. In all conjugates, the ligand binding competence toward αVβ3 (using both isolated receptors and αVβ3-overexpressing endothelial progenitor EP cells) and the kinase inhibitory activity (toward both isolated kinases and EPCs) remained almost untouched and comparable to the activity of the single active units. Compounds 1-3 showed interesting antiangiogenesis properties in an in vitro tubulogenic assay; furthermore, dimeric-RGD conjugate 3 strongly inhibited in vivo angiogenesis in Matrigel plug assays in FVB mice. These results offer proof-of-concept of how the covalent conjugation of two angiogenesis-related small modules may result in novel and stable molecules, which impair tumor-related angiogenesis with equal or even superior ability as compared to the single modules or their simple combinations. [ABSTRACT FROM AUTHOR]

The design and synthesis of a series of quinuclidine-containing spirooxazolidines ("spiroimidates") and their utility as α7 nicotinic acetylcholine receptor partial agonists are described. Selected members of the series demonstrated excellent selectivity for α7 over the highly homologous 5-HT3A receptor. Modification of the N-spiroimidate heterocycle substituent led to (1S,2R,4S)-N-isoquinolin-3-yl)-4′H-4-azaspiro[bicyclo[2.2.2]octane-2,5′oxazol]-2′-amine (BMS-902483), a potent α7 partial agonist, which improved cognition in preclinical rodent models. [ABSTRACT FROM AUTHOR]

The trace amine-associated receptor 1 (TAAR1) is a G-protein-coupled receptors (GPCR) potently activated by a variety of molecules besides trace amines (TAs), including thyroid hormone-derivatives like 3-iodothyronamine (T1AM), catechol-O-methyltransferase products like 3-methoxytyramine, and amphetamine-related compounds. Accordingly, TAAR1 is considered a promising target for medicinal development. To gain more insights into TAAR1 physiological functions and validation of its therapeutic potential, we recently developed a new class of thyronamine-like derivatives. Among them compound SG2 showed high affinity and potent agonist activity at mouse TAAR1. In the present work, we describe design, synthesis, and SAR study of a new series of compounds (1-16) obtained by introducing specific structural changes at key points of our lead compound SG2 skeleton. Five of the newly synthesized compounds displayed mTAAR1 agonist activity higher than both SG2 and T1AM. Selected diphenylmethane analogues, namely 1 and 2, showed potent functional activity in in vitro and in vivo models. [ABSTRACT FROM AUTHOR]

Indoleamine 2,3-dioxygenase 1 (IDO1) is an attractive target for anticancer therapy. Herein, we report a virtual screening study which led to the identification of compound 5 as a new IDO1 inhibitor. In order to improve the biological activity of the identified hit, arylthioindoles 6-30 were synthesized and tested. Among these, derivative 21 exhibited an IC50 value of 7 μM, being the most active compound of the series. Furthermore, compounds 5 and 21 induced a dose-dependent growth inhibition in IDO1 expressing cancer cell lines HTC116 and HT29. Three-dimensional quantitative structure-activity relationship studies were carried out in order to rationalize obtained results and suggest new chemical modifications. [ABSTRACT FROM AUTHOR]

As dysregulation of matrix metalloproteinase (MMP) activity is associated with a wide range of pathophysiological processes like cancer, atherosclerosis, and arthritis, MMPs represent a valuable target for the development of new therapeutics and diagnostic tools. We herein present the chiral pool syntheses, in vitro evaluation, and SAR studies of a series of d- and l-proline- as well as of (4R)-4-hydroxy-l-proline-derived MMP inhibitors possessing general formula 1. Some of the synthesized hydroxamic acids were found to be potent MMP inhibitors with IC50 values in the nanomolar range, also demonstrating no off-target effects toward the other tested Zn2+-dependent metalloproteases (ADAMs and meprins). Utilizing the structure of the (2S,4S)-configured 4-hydroxyproline derivative 4, a selective picomolar inhibitor of MMP-13, the radiolabeled counterpart [18F]4 was successfully synthesized. The radiotracer's biodistribution in mice as well as its serum stability were evaluated for assessing its potential use as a MMP-13 targeting PET imaging agent. [ABSTRACT FROM AUTHOR]

Synthetic and natural cyclic peptides provide a testing ground for studying membrane permeability in nontraditional drug scaffolds. Cyclic peptomers, which incorporate peptide and N-alkylglycine (peptoid) residues, combine the stereochemical and geometric complexity of peptides with the functional group diversity accessible to peptoids. We synthesized cyclic peptomer libraries by split-pool techniques, separately permuting side chain and backbone geometry, and analyzed their membrane permeabilities using the parallel artificial membrane permeability assay. Nearly half of the side chain permutations had permeability coefficients (Papp) > 1 × 10-6 cm/s. Some backbone geometries enhanced permeability due to their ability to form more stable intramolecular hydrogen bond networks compared with other scaffolds. These observations suggest that hexameric cyclic peptomers can have good passive permeability even in the context of extensive side chain and backbone variation, and that high permeability can generally be achieved within a relatively wide lipophilicity range. [ABSTRACT FROM AUTHOR]

The synthesis of four l-2′-deoxy-threose nucleoside phosphonates with the natural nucleobases adenine, thymine, cytosine, and guanosine has been performed. Especially the adenine containing analogue (PMDTA) was endowed with potent antiviral activity displaying an EC50 of 4.69 μM against HIV-1 and an EC50 value of 0.5 μM against HBV, whereas completely lacking cytotoxicity. The synthesis of a number of phosphonomonoamidate and phosphonobisamidate prodrugs of PMDTA led to a boost in antiviral potency. The most potent congeners were a l-aspartic acid diisoamyl ester phenoxy prodrug and a l-phenylalanine propyl ester phosphonobisamidate prodrug that both display anti-HIV and anti-HBV activities in the low nanomolar range and selectivity indexes of more than 300. [ABSTRACT FROM AUTHOR]

A novel series of tetrahydroprotoberberine derivatives (THPBs) were designed, synthesized, and evaluated as selective α1A-adrenergic receptors (AR) antagonists for the treatment of benign prostatic hyperplasia. On the basis of the pharmacophore model of the marketed drug silodosin, THPBs were modified by introducing an indole segment into their core scaffolds. In calcium assays, 7 out of 32 compounds displayed excellent antagonistic activities against α1A-ARs, with IC50 less than 250 nM. Among them, compound (S)-27 had the most potent biological activity; its IC50 toward α1A-AR was 12.8 ± 2.2 nM, which is 781 and 20 times more selective than that toward α1B- and α1D-AR, respectively. In the functional assay using isolated rat tissues, compound (S)-27 inhibited norepinephrine-induced urethra smooth muscle contraction potently (IC50 = 0.5 ± 0.3 nM), without inhibiting the aortic contraction (IC50 > 1000 nM), displaying a better tissue selectivity than the marketed drug silodosin. Additional results of preliminary safety studies (acute toxicity and hERG inhibition) and pharmacokinetics studies indicated the potential druggability for compound (S)-27 which is a promising lead for the development of selective α1A-AR antagonists for the treatment of BPH. [ABSTRACT FROM AUTHOR]

A high yield synthesis of a novel, small molecule, bisphosphonate-modified trans-cyclooctene (TCO-BP, 2) that binds to regions of active bone metabolism and captures functionalized tetrazines in vivo, via the bioorthogonal inverse electron demand Diels-Alder (IEDDA) cycloaddition, was developed. A 99mTc-labeled derivative of 2 demonstrated selective localization to shoulder and knee joints in a biodistribution study in normal mice. Compound 2 reacted rapidly with a 177Lu-labeled tetrazine in vitro, and pretargeting experiments in mice, using 2 and the 177Lu-labeled tetrazine, yielded high activity concentrations in shoulder and knee joints, with minimal uptake in other tissues. Pretargeting experiments with 2 and a novel 99mTc-labeled tetrazine also produced high activity concentrations in the knees and shoulders. Critically, both radiolabeled tetrazines showed negligible uptake in the skeleton and joints when administered in the absence of 2. Compound 2 can be utilized to target functionalized tetrazines to bone and represents a convenient reagent to test novel tetrazines for use with in vivo bioorthogonal pretargeting strategies. [ABSTRACT FROM AUTHOR]

Aromatase (CYP19) is a rate-limiting enzyme that catalyzes the biosynthesis of estrogens. Imaging agents based on aromatase inhibitors (AIs) have been developed for a PET/SPECT study. A series of compounds was synthesized based on YM511, which has previously been used for breast cancer treatment. Two examples of these derivatives, 4-(((4-iodophenyl)methyl)-4H-1,2,4-triazol-4-yl-amino)-benzonitrile (5) and 4-((1H-imidazol-1-yl)(4-iodobenzyl)amino)benzonitrile (11), displayed potent binding affinities to human aromatase (IC50 = 0.17 and 0.04 nM, respectively). Biodistribution and autoradiographic studies revealed that [125I]5 and [125I]11 were highly accumulated in the stomach (16.21 and 10.88% dose/g, respectively) and ovaries (8.56 and 3.32% dose/g, respectively) of female rats. Log P of [125I]5 was 2.49, meaning good brain penetration. Autoradiograms of brain sections showed a high uptake in the bed nucleus of the stria terminalis and amygdala. These results suggest that [125I]5 and [125I]11 are potent probes for aromatase imaging in both the brain and peripheral organs. [ABSTRACT FROM AUTHOR]

Simultaneous inhibition of phosphodiesterase 5 (PDE5) and histone deacetylases (HDAC) has recently been validated as a potentially novel therapeutic approach for Alzheimer's disease (AD). To further extend this concept, we designed and synthesized the first chemical series of dual acting PDE5 and HDAC inhibitors, and we validated this systems therapeutics approach. Following the implementation of structure- and knowledge-based approaches, initial hits were designed and were shown to validate our hypothesis of dual in vitro inhibition. Then, an optimization strategy was pursued to obtain a proper tool compound for in vivo testing in AD models. Initial hits were translated into molecules with adequate cellular functional responses (histone acetylation and cAMP/cGMP response element-binding (CREB) phosphorylation in the nanomolar range), an acceptable therapeutic window (<1 log unit), and the ability to cross the blood-brain barrier, leading to the identification of 7 as a candidate for in vivo proof-of-concept testing. [ABSTRACT FROM AUTHOR]

To better understand the contribution of methyl-lysine (Kme) binding proteins to various disease states, we recently developed and reported the discovery of 1 (UNC3866), a chemical probe that targets two families of Kme binding proteins, CBX and CDY chromodomains, with selectivity for CBX4 and -7. The discovery of 1 was enabled in part by the use of molecular dynamics simulations performed with CBX7 and its endogenous substrate. Herein, we describe the design, synthesis, and structure-activity relationship studies that led to the development of 1 and provide support for our model of CBX7-ligand recognition by examining the binding kinetics of our antagonists with CBX7 as determined by surface-plasmon resonance. [ABSTRACT FROM AUTHOR]

The design, synthesis, and structure-activity relationship of 1-phenoxy-2-aminoindanes as inhibitors of the Na+/H+ exchanger type 3 (NHE3) are described based on a hit from high-throughput screening (HTS). The chemical optimization resulted in the discovery of potent, selective, and orally bioavailable NHE3 inhibitors with 13d as best compound, showing high in vitro permeability and lacking CYP2D6 inhibition as main optimization parameters. Aligning 1-phenoxy-2-aminoindanes onto the X-ray structure of 13d then provided 3D-QSAR models for NHE3 inhibition capturing guidelines for optimization. These models showed good correlation coefficients and allowed for activity estimation. In silico ADMET models for Caco-2 permeability and CYP2D6 inhibition were also successfully applied for this series. Moreover, docking into the CYP2D6 X-ray structure provided a reliable alignment for 3D-QSAR models. Finally 13d, renamed as SAR197, was characterized in vitro and by in vivo pharmacokinetic (PK) and pharmacological studies to unveil its potential for reduction of obstructive sleep apneas. [ABSTRACT FROM AUTHOR]

The potent MCHR1 in vitro and in vivo antagonist activity of a series of cyclic tertiary alcohols derived from compound 2b is described. Subsequent pharmacokinetic and pharmacodynamic studies identified BMS-814580 (compound 10) as a highly efficacious antiobesity agent with a relatively clean in vitro and in vivo safety profile. [ABSTRACT FROM AUTHOR]

The emergence of multidrug-resistant bacteria emphasizes the urgent need for novel antibacterial compounds targeting unique cellular processes. Two-component signal transduction systems (TCSs) are commonly used by bacteria to couple environmental stimuli to adaptive responses, are absent in mammals, and are embedded in various pathogenic pathways. To attenuate these signaling pathways, we aimed to target the TCS signal transducer histidine kinase (HK) by focusing on their highly conserved adenosine triphosphate-binding domain. We used a structure-based drug design strategy that begins from an inhibitor-bound crystal structure and includes a significant number of structurally simplifiying "intuitive" modifications to arrive at the simple achiral, biaryl target structures. Thus, ligands were designed, leading to a series of thiophene derivatives. These compounds were synthesized and evaluated in vitro against bacterial HKs. We identified eight compounds with significant inhibitory activities against these proteins, two of which exhibited broad-spectrum antimicrobial activity. The compounds were also evaluated as adjuvants for the treatment of resistant bacteria. One compound was found to restore the sensivity of these bacteria to the respective antibiotics. [ABSTRACT FROM AUTHOR]

Screening of a small compound library at the three excitatory amino acid transporter subtypes 1-3 (EAAT1-3) resulted in the identification of compound (Z)-4-chloro-3-(5-((3-(2-ethoxy-2-oxoethyl)-2,4-dioxothiazolidin-5-ylidene)methyl)furan-2-yl)benzoic acid (1a) that exhibited a distinct preference as an inhibitor at EAAT1 (IC50 20 μM) compared to EAAT2 and EAAT3 (IC50 < 300 μM). This prompted us to subject 1a to an elaborate structure-activity relationship study through the purchase and synthesis and subsequent pharmacological characterization of a total of 36 analogues. Although this effort did not result in analogues with substantially improved inhibitory potencies at EAAT1 compared to that displayed by the hit, it provided a detailed insight into structural requirements for EAAT1 activity of this scaffold. The discovery of this new class of EAAT1-selective inhibitors not only supplements the currently available pharmacological tools in the EAAT field but also substantiates the notion that EAAT ligands not derived from α-amino acids hold considerable potential in terms of subtype-selective modulation of the transporters. [ABSTRACT FROM AUTHOR]