Localization of CaSR antagonists in CaSR-expressing medullary thyroid cancer

OBJECTIVE

Image-based localization of medullary thyroid cancer (MTC) and parathyroid glands would improve the surgical outcomes of these diseases. MTC and parathyroid glands express high levels of calcium-sensing receptor (CaSR). The aim of this study was to prove the concept that CaSR antagonists specifically localize to CaSR-expressing tumors in vivo.

DESIGN

We synthesized two isomers of a known CaSR calcilytic, Calhex 231, and four new analogs, which have a favorable structure for labeling. Their antagonistic activity was determined using immunoblots demonstrating decreased ERK1/2 phosphorylation after calcium stimulation in human embryonic kidney cells overexpressing CaSR. Compound 9 was further radiolabeled with (125)I and evaluated in nude mice with and without heterotransplanted xenografts of MTC cell lines, TT and MZ-CRC-1, that do and do not express CaSR, respectively.

RESULTS

Two newly synthesized compounds, 9 and 11, exhibited better antagonistic activity than Calhex 231. The half-life of (125)I-compound 9 in nude mice without xenografts was 9.9 hours. A biodistribution study in nude mice bearing both tumors demonstrated that the uptake of radioactivity in TT tumors was higher than in MZ-CRC-1 tumors at 24 hours: 0.39 ± 0.24 vs 0.18 ± 0.12 percentage of injected dose per gram of tissue (%ID/g) (P = .002), with a ratio of 2.25 ± 0.62. Tumor-to-background ratios for TT tumors, but not MZ-CRC-1 tumors, increased with time. Tumor-to-blood values increased from 2.02 ± 0.52 at 1 hour to 3.29 ± 0.98 at 24 hour (P = .015) for TT tumors, and 1.7 ± 0.56 at 1 hour to 1.48 ± 0.33 at 24 hour (P = .36) for MZ-CRC-1 tumors.

CONCLUSIONS

Our new CaSR antagonists specifically inhibit CaSR function in vitro, preferentially localize to CaSR-expressing tumors in vivo, and therefore have the potential to serve as scaffolds for further development as imaging pharmaceuticals.

2-cinnamamido, 2-(3-phenylpropiolamido), and 2-(3-phenylpropanamido)benzamides: synthesis, antiproliferative activity, and mechanism of action

Several new benzamides 4a-q were synthesized by stirring in pyridine the acid chlorides 3a-q with the appropriate anthranilamide derivatives 2a-g. Some of the synthesized compounds were evaluated for their in vitro antiproliferative activity against a panel of 5 human cell lines (K562 human chronic myelogenous leukemia cells, MCF-7 breast cancer cells, HTC-116 and HT26 colon cancer cells and NCI H460 non-small cell lung cancer cells).

Fully automated radiosynthesis of both enantiomers of [18F]Flubatine under GMP conditions for human application

A fully automatized radiosynthesis of (+)- and (-)-[(18)F]Flubatine ((+)- and (-)NCFHEB) by means of a commercially available synthesis module (TRACERlab FX FN) under GMP conditions is reported. Radiochemical yields of 30% within an overall synthesis time of 40 min were achieved in more than 70 individual syntheses. Specific activities were approximately 3000 GBq/μmol and radiochemical purity was determined to be at least 97%.

Synthesis and antibacterial evaluation of novel pleuromutilin derivatives

A series of novel pleuromutilin derivatives possessing thioether moiety has been synthesized via acylation reaction under mild conditions. Their in vitro antibacterial activity against methicillin-resistant Staphylococcus aureus, methicillin-resistant Staphylococcus epidermidis, Escherichia coli, and Streptococcus agalactiae were tested by agar dilution method and Oxford cup assay. Among the 17 compounds screened, 14-O-[(4-methoxybenzamide-2- methylpropane-2-yl) thioacetate] mutilin 4i, 14-O-[(2-aminobenzamide-2-methylpropane-2-yl) thioacetate] mutilin 5a and 14-O-[(4-aminobenzamide-2-methylpropane-2-yl) thioacetate] mutilin 5c were resulted as most active antibacterial agents.

Conformational, structural, vibrational and quantum chemical analysis on 4-aminobenzohydrazide and 4-hydroxybenzohydrazide--a comparative study

Experimental and theoretical quantum chemical studies were carried out on 4-hydroxybenzohydrazide (4HBH) and 4-aminobenzohydrazide (4ABH) using FTIR and FT-Raman spectral data. The structural characteristics and vibrational spectroscopic analysis were carried performed by quantum chemical methods with the hybrid exchange-correlation functional B3LYP using 6-31G(**), 6-311++G(**) and aug-cc-pVDZ basis sets. The most stable conformer of the title compounds have been determined from the analysis of potential energy surface. The stable molecular geometries, electronic and thermodynamic parameters, IR intensities, harmonic vibrational frequencies, depolarisation ratio and Raman intensities have been computed. Molecular electrostatic potential and frontier molecular orbitals were constructed to understand the electronic properties. The potential energy distributions (PEDs) were calculated to explain the mixing of fundamental modes. The theoretical geometrical parameters and the fundamental frequencies were compared with the experimental. The interactions of hydroxy and amino group substitutions on the characteristic vibrations of the ring and hydrazide group have been analysed.

Synthesis and antiviral activity of N-phenylbenzamide derivatives, a novel class of enterovirus 71 inhibitors

A series of novel N-phenylbenzamide derivatives were synthesized and their anti-EV 71 activities were assayed in vitro. Among the compounds tested, 3-amino-N-(4-bromophenyl)-4-methoxybenzamide (1e) was active against the EV 71 strains tested at low micromolar concentrations, with IC₅₀ values ranging from 5.7 ± 0.8–12 ± 1.2 μM, and its cytotoxicity to Vero cells (TC₅₀ = 620 ± 0.0 μM) was far lower than that of pirodavir (TC₅₀ = 31 ± 2.2 μM). Based on these results, compound 1e is a promising lead compound for the development of anti-EV 71 drugs.

Synthesis and evaluation of methylsulfonylnitrobenzamides (MSNBAs) as inhibitors of the thyroid hormone receptor-coactivator interaction

We previously identified the methylsulfonylnitrobenzoates (MSNBs) that block the interaction of the thyroid hormone receptor with its obligate transcriptional coactivators and prevent thyroid hormone signaling. As part of our lead optimization work we demonstrated that sulfonylnitrophenylthiazoles (SNPTs), which replace the ester linkage of MSNBs with a thiazole, also inhibited coactivator binding to TR. Here we report that replacement of the ester with an amide (methylsulfonylnitrobenzamides, MSNBA) also provides active TR antagonists.

Semisynthesis of N-acyl homoserinelactone derivatives and the antifeedant activity against Mythimna separata

Seven homoserine-lactone (HL) acylated derivatives (HL1-HL7) were synthesized to determine the differences in antifeedant affects. The differences between these derivatives and tutin against Mythimna separata were tested. The structural assignments of these semisynthetic compounds were examined based on their infrared radiaion (IR), electrospray ionization mass spectrometry (ESIMS), and ¹H- and ¹³C-nuclear magnetic resonance (¹³C-NMR) spectral data. Compound HL1 (N-(4-nitrobenzoyl)-homoserinelactone) is the optimized insecticidal agent among these compounds. In addition, the antifeedant activities between homoserinelactone and 7-hydroxycoumarin, tutin derivatives with the same acidylated substitutions were compared, which could help design and synthesize stronger novel botanical insecticides.

Synthesis of heavy metal chelating agent with four chelating groups of N1,N2,N4,N5-tetrakis(2-mercaptoethyl)benzene-1,2,4,5-tetracarboxamide (TMBTCA) and its application for Cu-containing wastewater

A novel heavy metal chelating agent, N(1),N(2),N(4),N(5)-tetrakis(2-mercaptoethyl) benzene-1,2,4,5-tetracarboxamide (TMBTCA), was designed with four chelating groups, and a facile one-step synthetic procedure was developed with pyromellitic dianhydride (PMDA) and cysteamine hydrochloride (CHC) as raw materials by aqueous acylation. The effects of mole ratio of reactants (CHC/PMDA), reaction temperature, and reaction time on the yield of TMBTCA were studied. Its application for Cu-containing wastewater was investigated. The experimental results showed that the maximum yield of TMBTCA was 75.92%, as the mole ratio of CHC/PMDA reached 4.8, reaction temperature was 5°C, and reaction time was 6h. It was observed that TMBTCA could effectively remove Cu(2+) and CuEDTA to much lower than 0.5 mg/L (the discharge limit of copper ions in China). Furthermore, TMBTCA showed more affinity for cadmium and copper than some traditional commercial precipitants, such as DTC, TBA and TMT, via comparison of their ability for heavy metal removal, and the precipitates of Cu-TMBTCA and Cd-TMBTCA presented good stability in leaching tests. The results can provide a reference for design and further research on new kind of heavy metal chelating agent with more bonding sites, especially for heavy metal precipitation in PCB wastewater treatment.

Design, synthesis and structure-activity relationship of novel inhibitors against H5N1 hemagglutinin-mediated membrane fusion

We reported previously that a small molecule named CL-385319 could inhibit H5N1 influenza virus infection by targeting hemagglutinin, the envelope protein mediating virus entry. In the present study, a novel series of derivatives focused on the structural variation of CL-385319 were synthesized as specific inhibitors against the H5 subtype of influenza A viruses. These small molecules inhibited the low pH-induced conformational change of hemagglutinin, thereby blocking viral entry into host cells. Compound 1l was the most active inhibitor in this series with an IC(50) of 0.22 μM. The structure-activity relationships analysis of these compounds showed that the 3-fluoro-5-(trifluoromethyl)benzamide moiety was very important for activity, and the -F group was a better substituent group than -CF(3) group in the phenyl ring. The inhibitory activity was sensitive to the benzamide because the oxygen and hydrogen of the amide served as H-bond acceptor and donor, respectively.

Novel synthetic route to the C-nucleoside, 2-deoxy benzamide riboside

2-Deoxy-C-nucleosides are a subcategory of C-nucleosides that has not been explored extensively, largely because the synthesis is less facile. Flexible synthetic procedures giving access to 2-deoxy-C-nucleosides are therefore of interest. To exemplify the versatility and highlight the limitations of a synthetic route recently developed to that effect, the first synthesis of 2-deoxy benzamide riboside is reported. Biological properties of this novel C-nucleoside are also discussed.

Antioxidant activity of new aramide nanoparticles containing redox-active N-phthaloyl valine moieties in the hepatic cytochrome P450 system in male rats

We report the synthesis of aramide nanoparticles containing a chiral N-phthaloyl valine moiety and their antioxidant activities on hepatic contents of cytochrome P₄₅₀, amidopyrene N-demethylase, aniline-4-hyroxylase and induced the hepatic content of cytochrome b5 and nicotinamide adenine dinucleotide phosphate (NADPH) cytochrome C-reductase. Polymers were obtained as well-separated spherical nanoparticles while highly aggregated particles via H-bonding organization of the aramide-containing pyridine led to a thin layer formation. The effects of the nanoparticles and CCl₄ on enzyme activities and thiobarbituric acid reactive substances (TBARS) levels of male rat liver were studied. Pretreatments of rats with the polyamides prior to the administration of CCl₄ decreased the hepatic content of the tested enzymes. Doses reduced the toxic effects exerted by (•CCl₃) upon the liver through inhibition of the cytochrome P₄₅₀ system. Inhibition of such metabolizing enzymes could reduce the carcinogenic effects of chemical carcinogens.

Synthesis and antimicrobial screening of N-[2-(2/4-substituted phenyl)-1-(5/6 substituted 1H- benzimidazol-2-yl)vinyl]benzamides

A series of (benzamidostyryl)benzimidazole derivatives were synthesized by hydrolyzing 2-phenyl-4-(substituted)benzylidene-5-oxazolones, the azlactone precursors in an acidic medium and treating the product with substituted o-phenylenediamine (OPDA) in situ. The structures of the synthesized compounds were confirmed by spectral and elemental analyses. All synthesized compounds were screened for their in vito antimicrobial activities against some identifiable strains. Thereby, it was found that only nitro substituted benzimidazoles exhibited good to moderate antibacterial activity, while other derivatives were devoid of any antimicrobial effect.

Design of potent and selective hybrid inhibitors of the mitotic kinase Nek2: structure-activity relationship, structural biology, and cellular activity

We report herein a series of Nek2 inhibitors based on an aminopyridine scaffold. These compounds have been designed by combining key elements of two previously discovered chemical series. Structure based design led to aminopyridine (R)-21, a potent and selective inhibitor able to modulate Nek2 activity in cells.

Angiogenesis inhibitors identified by cell-based high-throughput screening: synthesis, structure-activity relationships and biological evaluation of 3-[(E)-styryl]benzamides that specifically inhibit endothelial cell proliferation

Proliferation of endothelial cells is critical for angiogenesis. We report orally available, in vivo active antiangiogenic agents which specifically inhibit endothelial cell proliferation. After identifying human umbilical vein endothelial cell (HUVEC) proliferation inhibitors from a cell-based high-throughput screening (HTS), we eliminated those compounds which showed cytotoxicity against HCT116 and vascular endothelial growth factor receptor 2 (VEGFR-2) inhibitory activity. Evaluations in human Calu-6 xenograft model delivered lead compound 1. Following extensive lead optimization and alteration of the scaffold we discovered 32f and 32g, which both inhibited the proliferation and tube formation of HUVEC without showing inhibitory activity against any of 25 kinases or cytotoxicity against either normal fibroblasts or 40 cancer cell lines. Upon oral administration, 32f and 32g had good pharmacokinetic profiles and potent antitumor activity and decreased microvessel density (MVD) in Calu-6 xenograft model. Combination therapy with a VEGFR inhibitor enhanced the in vivo efficacy. These results suggest that 32f and 32g may have potential for use in cancer treatment.

Synthesis, characterization and biological activity of some 1, 3, 4-thiadiazol derivatives

Thiadiazoles are their derivatives exhibit a wide variety of pharmacological activities such as Antibacterial and anti-inflammatory. In the present study we have synthesized derivatives some 2,5 substituted 1,3,4- thiadiazoles. The structures of these synthesized compounds were confirmed by IR, NMR, and MASS spectra data. These compounds were evaluated for varies biological activities such as antibacterial and anti-inflammatory activity.

t-Bu2SiF-derivatized D2-receptor ligands: the first SiFA-containing small molecule radiotracers for target-specific PET-imaging

The synthesis, radiolabeling and in vitro evaluation of new silicon-fluoride acceptor (SiFA) derivatized D(2)-receptor ligands is reported. The SiFA-technology simplifies the introduction of fluorine-18 into target specific biomolecules for Positron-Emission-Tomography (PET). However, one of the remaining challenges, especially for small molecules such as receptor-ligands, is the bulkiness of the SiFA-moiety. We therefore synthesized four Fallypride SiFA-conjugates derivatized either directly at the benzoic acid ring system (SiFA-DMFP, SiFA-FP, SiFA-DDMFP) or at the butyl-side chain (SiFA-M-FP) and tested their receptor affinities. We found D(2)-receptor affinities for all compounds in the nanomolar range (K(i(SiFA-DMFP)) = 13.6 nM, K(i(SiFA-FP)) = 33.0 nM, K(i(SiFA-DDMFP)) = 62.7 nM and K(i(SiFA-M-FP)) = 4.21 nM). The radiofluorination showed highest yields when 10 nmol of the precursors were reacted with [(18)F]fluoride/TBAHCO(3) in acetonitrile. After a reversed phased cartridge purification the desired products could be isolated as an injectable solution after only 10 min synthesis time with radiochemical yields (RCY) of more than 40% in the case of SiFA-DMFP resulting in specific activities >41 GBq/µmol (>1,100 Ci/mmol). Furthermore, the radiolabeled products were shown to be stable in the injectable solutions, as well as in human plasma, for at least 90 min.

Protective effects of veskamide, enferamide, becatamide, and oretamide on H2O2-induced apoptosis of PC-12 cells

Veskamide, enferamide, becatamide, and oretamide are phenolic amides whose analogues are found in plants. In this study, the four amides were prepared by chemical synthesis and their protective effects on H(2)O(2)-induced apoptosis in PC-12 cells were investigated. The syntheses were relatively simple and the yields were more than 43%. Using NMR spectroscopic methods, the chemical structures of veskamide, enferamide, becatamide, and oretamide were confirmed. The decreasing order of the protective effects on H(2)O(2)-induced apoptosis was becatamide>enferamide≥oretamide>veskamide. In fact, becatamide suppressed H(2)O(2)-induced mitochondrial membrane depolarization in a dose-dependent manner. At the concentration of 10 μM, becatamide maintained mitochondrial membrane depolarization at 16% compared to 51% in H(2)O(2)-treated PC-12 cells (P<0.05). Also, at the same concentration, becatamide inhibited H(2)O(2)-induced caspase-9 activation and caspase-independent chromatin condensation by 68% (P<0.05) and 73% (P<0.05), respectively. This is the first report about the chemical synthesis of becatamide and its potential biological activity to inhibit H(2)O(2)-induced apoptosis of PC-12 cells via protecting mitochondrial membrane integrity, thereby suppressing caspase-9 activation and chromatin condensation.

Synthesis, antiproliferative activity, and mechanism of action of a series of 2-{[(2E)-3-phenylprop-2-enoyl]amino}benzamides

Several new 2-{[(2E)-3-phenylprop-2-enoyl]amino}benzamides 12a-s and 17t-v were synthesized by stirring in pyridine the (E)-3-(2-R1-3-R2-4-R3-phenyl)acrylic acid chlorides 11c-k and 11t-v with the appropriate anthranilamide derivatives 10a-c or the 5-iodoanthranilic acid 13. Some of the synthesized compounds were evaluated for their in vitro antiproliferative activity against the full NCI tumor cell line panel derived from nine clinically isolated cancer types (leukemia, non-small cell lung, colon, CNS, melanoma, ovarian, renal, prostate and breast). COMPARE analysis, effects on tubulin polymerization in cells and with purified tubulin, and effects on cell cycle distribution for 17t, the most active of the series, indicate that these new antiproliferative compounds act as antitubulin agents.

Effect of structural modification in the amine portion of substituted aminobutyl-benzamides as ligands for binding σ1 and σ2 receptors

5-Bromo-N-[4-(6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-butyl)]-2,3-dimethoxy-benzamide (1) is one of the most potent and selective σ(2) receptor ligands reported to date. A series of new analogs, where the amine ring fused to the aromatic ring was varied in size (5-7) and the location of the nitrogen in this ring was modified, has been synthesized and assessed for their σ(1)/σ(2) binding affinity and selectivity. The binding affinity of an open-chained variant of 1 was also evaluated. Only the five-membered ring congener of 1 displayed a higher σ(1)/σ(2) selectivity, derived from a higher σ(2) affinity and a lower σ(1) affinity. Positioning the nitrogen adjacent to the aromatic ring in the five-membered and six-membered ring congeners dramatically decreased affinity for both subtypes. Thus, location of the nitrogen within a constrained ring is confirmed to be key to the exceptional σ(2) receptor binding affinity and selectivity for this active series.

Aminocarbonyl arylvinylbenzamides as gastric sparing anti-inflammatory agents

Some (E/Z)-aminocarbonyl arylvinylbenzamides (B1-B15) were synthesized, evaluated for anti-inflammatory activity and ulcerogenic tendency, and their effect on gastro-intestinal motility in the rats was studied. These benzamides comprising of aliphatic unsaturated region situated between two amide linkages were synthesized by nucleophilic ring opening of appropriate azlactones (AZ1-AZ4) by suitable amines. The characterization of newly synthesized benzamides was performed by IR, (1)H- and (13)C-NMR, mass and elemental analysis. Amongst the tested compounds, benzamide B1, B2, B4, B5, and B13 were able to produce comparable or superior anti-inflammatory activity at 10 and 20 mg/kg p.o. dose with respect to standard diclofenac in carrageenan induced rat paw edema model with lessened propensity to cause gastro-intestinal hypermotility and were found to have nil tendencies to generate gastric ulcers.