A promising in silico protocol to develop novel PPARγ antagonists as potential anticancer agents: Design, synthesis and experimental validation via PPARγ protein activity and competitive binding assay

Peroxisome proliferator-activated receptor gamma (PPARγ), a member of the nuclear receptor superfamily is an excellent example of targets that orchestrates cancer, inflammation, lipid and glucose metabolism. We report a protocol for the development of novel PPARγ antagonists by employing 3D QSAR based virtual screening for the identification of ligands with anticancer properties. The models are generated based on a large and diverse set of PPARγ antagonist ligands by the HYPOGEN algorithm using Discovery Studio 2019 drug design software. Among the 10 hypotheses generated, Hypotheses 2 showed the highest correlation coefficient values of 0.95 with less RMS deviation of 1.193. Validation of the developed pharmacophore model was performed by Fischer's randomization and screening against test and decoy set. The GH score or goodness score was found to be 0.81 indicating moderate to a good model. The selected pharmacophore model Hypo 2 was used as a query model for further screening of 11,145 compounds from the PubChem, sc-PDB structure database, and designed novel ligands. Based on fit values and ADMET filter, the final 10 compounds with the predicated activity of ≤ 3 nM were subjected for docking analysis. Docking analysis revealed the unique binding mode with hydrophobic amino acid that can cause destabilization of the H12 which is an important molecular mechanism to prove its antagonist action. Based on high CDocker scores, Cpd31 was synthesized, purified, analyzed and screened for PPARγ competitive binding by TR-FRET assay. The biochemical protein binding results matched the predicted results. Further, Cpd31 was screened against cancer cells and validated the results.

Novel Pyridine Bioisostere of Cabozantinib as a Potent c-Met Kinase Inhibitor: Synthesis and Anti-Tumor Activity against Hepatocellular Carcinoma

Two novel bioisosteres of cabozantinib, 3 and 4, were designed and synthesized. The benzene ring in the center of the cabozantinib structure was replaced by trimethylpyridine (3) and pyridine (4), respectively. Surprisingly, the two compounds showed extremely contrasting mesenchymal-epithelial transition factor (c-Met) inhibitory activities at 1 μM concentration (4% inhibition of 3 vs. 94% inhibition of 4). The IC₅₀ value of compound 4 was 4.9 nM, similar to that of cabozantinib (5.4 nM). A ligand-based docking study suggested that 4 includes the preferred conformation for the binding to c-Met in the conformational ensemble, but 3 does not. The anti-proliferative activity of compound 4 against hepatocellular carcinoma (Hep3B and Huh7) and non-small-cell lung cancer (A549 and H1299) cell lines was better than that of cabozantinib, whereas 3 did not show a significant anti-proliferative activity. Moreover, the tumor selectivity of compound 4 toward hepatocellular carcinoma cell lines was higher than that of cabozantinib. In the xenograft chick tumor model, compound 4 inhibited Hep3B tumor growth to a much greater extent than cabozantinib. The present study suggests that compound 4 may be a good therapeutic candidate against hepatocellular carcinoma.

Design, synthesis and biological evaluation of anilide (dicarboxylic acid) shikonin esters as antitumor agents through targeting PI3K/Akt/mTOR signaling pathway

Triple-negative breast cancer (TNBC) has an unfavorable prognosis attribute to its low differentiation, rapid proliferation and high distant metastasis rate. PI3K/Akt/mTOR as an intracellular signaling pathway plays a key role in the cell proliferation, migration, invasion, metabolism and regeneration. In this work, we designed and synthesized a series of anilide (dicarboxylic acid) shikonin esters targeting PI3K/Akt/mTOR signaling pathway, and assessed their antitumor effects. Through three rounds of screening by computer-aided drug design method (CADD), we preliminarily obtained sixteen novel anilide (dicarboxylic acid) shikonin esters and identified them as excellent compounds. CCK-8 assay results demonstrated that compound M9 exhibited better antiproliferative activities against MDA-MB-231, A549 and HeLa cell lines than shikonin (SK), especially for MDA-MB-231 (M9: IC₅₀ = 4.52 ± 0.28 μM; SK: IC₅₀ = 7.62 ± 0.26 μM). Moreover, the antiproliferative activity of M9 was better than that of paclitaxel. Further pharmacological studies showed that M9 could induce apoptosis of MDA-MB-231 cells and arrest the cell cycle in G2/M phase. M9 also inhibited the migration of MDA-MB-231 cells by inhibiting Wnt/β-catenin signaling pathway. In addition, western blot results showed that M9 could inhibit cell proliferation and migration by down-regulating PI3K/Akt/mTOR signaling pathway. Finally, a three-dimensional quantitative structure-activity relationship (3D-QSAR) model was also constructed to provide a basis for further development of shikonin derivatives as potential antitumor drugs through structure-activity relationship analysis. To sum up, M9 could be a potential candidate for TNBC therapy.

CAP rigidification of MS-275 and chidamide leads to enhanced antiproliferative effects mediated through HDAC1, 2 and tubulin polymerization inhibition

The study focuses on the prudent design and synthesis of anilide type class I HDAC inhibitors employing a functionalized pyrrolo[2,3-d]pyrimidine skeleton as the surface recognition part. Utilization of the bicyclic aromatic ring to fabricate the target compounds was envisioned to confer rigidity to the chemical architecture of MS-275 and chidamide. In-vitro enzymatic and cellular assays led to the identification of compound 7 as a potent inhibitor of HDAC1 and 2 isoform that exerted substantial cell growth inhibitory effects against human breast MDA-MB-231, cervical HeLa, breast MDA-MB-468, colorectal DLD1, and colorectal HCT116 cell lines with an IC₅₀ values of 0.05-0.47 μM, better than MS-275 and chidamide. In addition, the anilide 7 was also endowed with a superior antiproliferative profile than MS275 and chidamide towards the human cutaneous T cell lymphoma (HH and HuT78), leukemia (HL60 and KG-1), and HDACi sensitive/resistant gastric cell lines (YCC11 and YCC3/7). Exhaustive exploration of the construct 7 confirmed it to be a microtubule-targeting agent that could trigger the cell-cycle arrest in mitosis. In pursuit of extracting the benefits of evidenced microtubule-destabilizing activity of the anilide 7, it was further evaluated against non-small-cell lung cancer cell lines as well as the multiple-drug resistant uterine cancer cell line (MES-SA/Dx5) and overwhelmingly positive results in context of inhibitory effects were attained. Furthermore, molecular modelling studies were performed and some key interactions of the anilide 7 with the amino acid residues of the active site of HDAC1 isoform and tubulin were figured out.

An example of how to establish the thermodynamic stability relationship between two polymorphs of a compound highly prone to solvate formation

Upon transition from research to development, a new chemical entity, which acts upon the Kv1.5-potassium channel and blocks potassium flow in the atrium of the human heart, has been subjected to a crystallization screen. The sodium salt of an anthranilic acid amide with a heteroarylsulfonyl side chain forms solvates from all tested organic solvents. Solvent-free crystalline phases can only be obtained by drying certain solvates under suitable conditions. Two well crystalline solvent-free phases can be obtained this way. Three different methods were applied to determine their thermodynamic stability relationship from melting, solution and eutectic melting data. The different approaches are discussed and compared with respect to their accuracy and limitations.

Structure-Based Design of a Potent and Selective Covalent Inhibitor for SRC Kinase That Targets a P-Loop Cysteine

SRC is a major regulator of many signaling pathways and contributes to cancer development. However, development of a selective SRC inhibitor has been challenging, and FDA-approved SRC inhibitors, dasatinib and bosutinib, are multitargeted kinase inhibitors. Here, we describe our efforts to develop a selective SRC covalent inhibitor by targeting cysteine 277 on the P-loop of SRC. Using a promiscuous covalent kinase inhibitor (CKI) SM1-71 as a starting point, we developed covalent inhibitor 15a, which discriminates SRC from other covalent targets of SM1-71 including TAK1 and FGFR1. As an irreversible covalent inhibitor, compound 15a exhibited sustained inhibition of SRC signaling both in vitro and in vivo. Moreover, 15a exhibited potent antiproliferative effects in nonsmall cell lung cancer cell lines harboring SRC activation, thus providing evidence that this approach may be promising for further drug development efforts.

Reversible Small Molecule Inhibitors of MAO A and MAO B with Anilide Motifs

BACKGROUND

Ligands consisting of two aryl moieties connected via a short spacer were shown to be potent inhibitors of monoamine oxidases (MAO) A and B, which are known as suitable targets in treatment of neurological diseases. Based on this general blueprint, we synthesized a series of 66 small aromatic amide derivatives as novel MAO A/B inhibitors.

METHODS

The compounds were synthesized, purified and structurally confirmed by spectroscopic methods. Fluorimetric enzymological assays were performed to determine MAO A/B inhibition properties. Mode and reversibility of inhibition was determined for the most potent MAO B inhibitor. Docking poses and pharmacophore models were generated to confirm the in vitro results.

RESULTS

N-(2,4-Dinitrophenyl)benzo[d][1,3]dioxole-5-carboxamide (55, ST-2043) was found to be a reversible competitive moderately selective MAO B inhibitor (IC₅₀ = 56 nM, K_i = 6.3 nM), while N-(2,4-dinitrophenyl)benzamide (7, ST-2023) showed higher preference for MAO A (IC₅₀ = 126 nM). Computational analysis confirmed in vitro binding properties, where the anilides examined possessed high surface complementarity to MAO A/B active sites.

CONCLUSION

The small molecule anilides with different substitution patterns were identified as potent MAO A/B inhibitors, which were active in nanomolar concentrations ranges. These small and easily accessible molecules are promising motifs, especially for newly designed multitargeted ligands taking advantage of these fragments.

Bioactivity of Methoxylated and Methylated 1-Hydroxynaphthalene-2-Carboxanilides: Comparative Molecular Surface Analysis

A series of twenty-six methoxylated and methylated N-aryl-1-hydroxynaphthalene- 2-carboxanilides was prepared and characterized as potential anti-invasive agents. The molecular structure of N-(2,5-dimethylphenyl)-1-hydroxynaphthalene-2-carboxamide as a model compound was determined by single-crystal X-ray diffraction. All the analysed compounds were tested against the reference strain Staphylococcus aureus and three clinical isolates of methicillin-resistant S.aureus as well as against Mycobacterium tuberculosis and M. kansasii. In addition, the inhibitory profile of photosynthetic electron transport in spinach (Spinacia oleracea L.) chloroplasts was specified. In vitro cytotoxicity of the most effective compounds was tested on the human monocytic leukaemia THP-1 cell line. The activities of N-(3,5-dimethylphenyl)-, N-(3-fluoro-5-methoxy-phenyl)- and N-(3,5-dimethoxyphenyl)-1-hydroxynaphthalene-2-carbox- amide were comparable with or even better than the commonly used standards ampicillin and isoniazid. All promising compounds did not show any cytotoxic effect at the concentration >30 µM. Moreover, an in silico evaluation of clogP features was performed for the entire set of the carboxamides using a range of software lipophilicity predictors, and cross-comparison with the experimentally determined lipophilicity (log k), in consensus lipophilicity estimation, was conducted as well. Principal component analysis was employed to illustrate noticeable variations with respect to the molecular lipophilicity (theoretical/experimental) and rule-of-five violations. Additionally, ligand-oriented studies for the assessment of the three-dimensional quantitative structure–activity relationship profile were carried out with the comparative molecular surface analysis to determine electron and/or steric factors that potentially contribute to the biological activities of the investigated compounds.

Novel dual inhibitors targeting CDK4 and VEGFR2 synergistically suppressed cancer progression and angiogenesis

Based on the significantly synergistic effects of CDK4 and VEGFR2 inhibitors on growth of cancer cells, a series of novel multi-kinase inhibitors targeting CDK4 and VEGFR2 were designed, synthesized and evaluated, among which Roxyl-ZV-5J exhibited potent and balanced activities against both CDK4 and VEGFR2 with half-maximal inhibitory concentration at the nanomolar level. It effectively induced breast and cervical cancer cell cycle arrest and cell apoptosis. Roxyl-ZV-5J also inhibited the proliferation, tube formation and VEGFR2 downstream signaling pathways of HUVECs. Oral administration of Roxyl-ZV-5J led to significant tumor regression and anti-angiogenesis without obvious toxicity in SiHa xenograft mouse model. In addition, this compound showed good pharmacokinetics. This study confirmed a new tool for dual CDK-VEGFR2 pathways inhibition achieved with a single molecule, which provided valuable leads for further structural optimization and anti-angiogenesis and anti-tumor mechanism study.

One-pot synthesis of anilides, herbicidal activity and molecular docking study

BACKGROUND

In the context of the demand for more efficient herbicides, the aim of the present work was to synthesize anilides via simple methods, and evaluate their herbicidal activities through seed germination assays. In silico studies were carried out to identify the enzyme target sites in plants for the most active anilides.

RESULTS

A total of 18 anilides were prepared via one-pot reaction in yields that varied from 36 to 98% through reactions of anilines with sorbic chloride and hexanoic anhydride. According to seed germination assays in three dicotyledonous and one monocotyledonous plant species, the most active anilides showed root and shoot growth inhibition superior to that of Dual (S-metolachlor). In silico studies indicated that histone deacetylase was the probable enzyme target site in plants for these substances. The affinities of the most active anilides for the binding sites of this enzyme were equal to or higher than those calculated for its inhibitors.

CONCLUSION

Anilides 4d, 4e, 4 g, and 4 h are promising candidates for the development of novel herbicides. According to in silico studies, they inhibit histone deacetylase in plants, which can be exploited for the development of new weed control methods. © 2018 Society of Chemical Industry.

[18F]FEPPA a TSPO Radioligand: Optimized Radiosynthesis and Evaluation as a PET Radiotracer for Brain Inflammation in a Peripheral LPS-Injected Mouse Model

[¹⁸F]FEPPA is a specific ligand for the translocator protein of 18 kDa (TSPO) used as a positron emission tomography (PET) biomarker for glial activation and neuroinflammation. [¹⁸F]FEPPA radiosynthesis was optimized to assess in a mouse model the cerebral inflammation induced by an intraperitoneal injection of Salmonella enterica serovar Typhimurium lipopolysaccharides (LPS; 5 mg/kg) 24 h before PET imaging. [¹⁸F]FEPPA was synthesized by nucleophilic substitution (90 °C, 10 min) with tosylated precursor, followed by improved semi-preparative HPLC purification (retention time 14 min). [¹⁸F]FEPPA radiosynthesis were carried out in 55 min (from EOB). The non-decay corrected radiochemical yield were 34 ± 2% (n = 17), and the radiochemical purity greater than 99%, with a molar activity of 198 ± 125 GBq/µmol at the end of synthesis. Western blot analysis demonstrated a 2.2-fold increase in TSPO brain expression in the LPS treated mice compared to controls. This was consistent with the significant increase of [¹⁸F]FEPPA brain total volume of distribution (V_T) estimated with pharmacokinetic modelling. In conclusion, [¹⁸F]FEPPA radiosynthesis was implemented with high yields. The new purification/formulation with only class 3 solvents is more suitable for in vivo studies.

Identification and Characterizations of Novel, Selective Histone Methyltransferase SET7 Inhibitors by Scaffold Hopping- and 2D-Molecular Fingerprint-Based Similarity Search

SET7, serving as the only histone methyltransferase that monomethylates 'Lys-4' of histone H3, has been proved to function as a key regulator in diverse biological processes, such as cell proliferation, transcriptional network regulation in embryonic stem cell, cell cycle control, protein stability, heart morphogenesis and development. What's more, SET7 is involved inthe pathogenesis of alopecia aerate, breast cancer, tumor and cancer progression, atherosclerosis in human carotid plaques, chronic renal diseases, diabetes, obesity, ovarian cancer, prostate cancer, hepatocellular carcinoma, and pulmonary fibrosis. Therefore, there is urgent need to develop novel SET7 inhibitors. In this paper, based on DC-S239 which has been previously reported in our group, we employed scaffold hopping- and 2D fingerprint-based similarity searches and identified DC-S285 as the new hit compound targeting SET7 (IC₅₀ = 9.3 μM). Both radioactive tracing and NMR experiments validated the interactions between DC-S285 and SET7 followed by the second-round similarity search leading to the identification ofDC-S303 with the IC₅₀ value of 1.1 μM. In cellular level, DC-S285 retarded tumor cell proliferation and showed selectivity against MCF7 (IC₅₀ = 21.4 μM), Jurkat (IC₅₀ = 2.2 μM), THP1 (IC₅₀ = 3.5 μM), U937 (IC₅₀ = 3.9 μM) cell lines. Docking calculations suggested that DC-S303 share similar binding mode with the parent compoundDC-S239. What's more, it presented good selectivity against other epigenetic targets, including SETD1B, SETD8, G9a, SMYD2 and EZH2. DC-S303 can serve as a drug-like scaffold which may need further optimization for drug development, and can be used as chemical probe to help the community to better understand the SET7 biology.

Design, synthesis, and initial evaluation of affinity-based small molecular probe for detection of WDR5

WDR5, a subunit of the SET/MLL complex, plays critical roles in various biological progresses and are abnormally expressed in many cancers. Here we report the design, synthesis, and biochemical characterization of a new chemical tool to capture WDR5 protein. The probe is a biotinylated version of compound 30 that is a potent WDR5 inhibitor we previously reported. Importantly, the probe displayed high affinity to WDR5 protein in vitro binding potency and showed the ability in specifically and real time monitoring WDR5 protein. Further, the biotinylated tag of the probe enabled selectively "chemoprecipitation" of WDR5 from whole cell lysates of MV4-11. This probe provided a new approach to identify the overexpressed WDR5 protein in different cancer cells and applications to proteomic analysis of WDR5 and WDR5-binding partners.

Preparation of tritium-labeled PF-622, a novel fatty acid amide hydrolase inhibitor

To make a detailed characterization of the mechanism of inhibition and selectivity of a novel fatty acid amide hydrolase inhibitor PF-622, 3 tritium isotopomers were prepared. [³ H]PF-622a labeled at the piperazine ring B and [³ H]PF-622b labeled at both the ring B and phenyl ring A were synthesized via catalytic H(hydrogen)-T(tritium) exchange, utilizing 1 equiv and excess of Crabtree's catalyst, respectively. The preparation of [³ H]PF-622c labeled only at the phenyl ring A was achieved via tritiodebromination of the bromide precursor, using Pd(PPh₃ )₄ as a catalyst. The observations from these tritiation reactions might open a new perspective in the labeling for the targets having a similar moiety.

Novel 2-Phenoxyanilide Congeners Derived from a Hit Structure of the TCAMS: Synthesis and Evaluation of Their in Vitro Activity against Plasmodium falciparum

The Tres Cantos Antimalarial Compound Set (TCAMS) is a publicly available compound library which contains 13533 hit structures with confirmed activity against Plasmodium falciparum, the infective agent responsible for malaria tropica. The TCAMS provides a variety of starting points for the investigation of new antiplasmodial drug leads. One of the promising compounds is TCMDC-137332, which seemed to be a good starting point due to its antiplasmodial potency and its predicted physicochemical properties. Several new analogues based on a 2-phenoxyanilide scaffold were synthesized by standard amide coupling reactions and were fully characterized regarding their identity and purity by spectroscopic and chromatographic methods. Furthermore, the results of the biological evaluation of all congeners against Plasmodium falciparum NF54 strains are presented. The findings of our in vitro screening could not confirm the presumed nanomolar antiplasmodial activity of TCMDC-137332 and its derivatives.

Inhibition of N-type calcium channels by fluorophenoxyanilide derivatives

A set of fluorophenoxyanilides, designed to be simplified analogues of previously reported ω-conotoxin GVIA mimetics, were prepared and tested for N-type calcium channel inhibition in a SH-SY5Y neuroblastoma FLIPR assay. N-type or Ca_v2.2 channel is a validated target for the treatment of refractory chronic pain. Despite being significantly less complex than the originally designed mimetics, up to a seven-fold improvement in activity was observed.

Synthesis and antimycobacterial properties of ring-substituted 6-hydroxynaphthalene-2-carboxanilides

In this study, a series of twenty-two ring-substituted 6-hydroxynaphthalene-2-carboxanilides was prepared and characterized. Primary in vitro screening of the synthesized compounds was performed against Mycobacterium tuberculosis H37Ra, Mycobacterium avium complex and M. avium subsp. paratuberculosis. Derivatives substituted by trifluoromethyl, bromo, methyl and methoxy moieties in C'(3) and C'(4) positions of the anilide ring showed 2-fold higher activity against M. tuberculosis than isoniazid and 4.5-fold higher activity against M. avium subsp. paratuberculosis than rifampicin. 6-Hydroxy-N-(2-methylphenyl)naphthalene-2-carboxamide had MIC=29 μM against M. avium complex. A significant decrease of mycobacterial cell metabolism (viability of M. tuberculosis H37Ra) was observed using MTT assay. Screening of the cytotoxicity of the most effective antimycobacterial compounds was performed using the THP-1 cells, and no significant lethal effect was observed. The structure-activity relationships are discussed.

Photocatalytic synthesis of anilides from nitrobenzenes under visible light irradiation: 2 in 1 reaction

An efficient method has been developed for the synthesis of a series of anilides via a two in one reaction of nitrobenzenes with anhydride in the presence of TiO2 as a nanocatalyst and photocatalyst under sunlight or blue LED irradiation. In this method simultaneously, nitrobenzenes convert to the corresponding anilines via photocatalytic reduction on the TiO2 surface, and a condensation of aniline with the anhydride performed on the Lewis acid site of the TiO2 surface. Interestingly amidation step leads to the promotion of better reaction and good selectivity in reduction of nitrocompounds. This method is simple, rapid, high yield, and green.

Synthesis, spectroscopic characterization and in vitro antimicrobial, anticancer and antileishmanial activities as well interaction with Salmon sperm DNA of newly synthesized carboxylic acid derivative, 4-(4-methoxy-2-nitrophenylamino)-4-oxobutanoic acid

This paper stresses on the synthesis, characterization of novel carboxylic acid derivative and its application in pharmaceutics. Carboxylic acid derivatives have a growing importance in medicine, particularly in oncology. A novel carboxylic acid, 4-(4-methoxy-2-nitrophenylamino)-4-oxobutanoic acid, was synthesized and characterized by elemental analysis, FT-IR, NMR ((1)H, and (13)C), mass spectrometry and single crystal X-ray structural analysis. The structure of the title compound, C11H12N2O6, shows the molecules dimerised by short intramolecular OH⋯O hydrogen bonds. The compound was screened for in vitro antimicrobial, anticancer, and antileishmanial activities as well as interaction with SS-DNA. The compound was also checked for in vitro anticancer activity against BHK-21, H-157 and HCEC cell lines, and showed significant anticancer activity. The compound was almost non-toxic towards human corneal epithelial cells (HCEC) and did not show more than 7.4% antiproliferative activity when used at the 2.0μg/mL end concentration. It was also tested for antileishmanial activity against the promastigote form of leishmania major and obtained attractive result. DNA interaction study exposes that the binding mode of the compound with SS-DNA is an intercalative as it results in hypochromism along with minor red shift. A new and efficient strategy to identify pharmacophores sites in carboxylic acid derivative for antibacterial/antifungal activity using Petra, Osiris and Molinspiration (POM) analyses was also carried out.

Preparation and biological properties of ring-substituted naphthalene-1-carboxanilides

In this study, a series of twenty-two ring-substituted naphthalene-1-carboxanilides were prepared and characterized. Primary in vitro screening of the synthesized carboxanilides was performed against Mycobacteriumavium subsp. paratuberculosis. N-(2-Methoxyphenyl)naphthalene-1-carboxamide, N-(3-methoxy-phenyl)naphthalene-1-carboxamide, N-(3-methylphenyl)naphthalene-1-carboxamide, N-(4-methylphenyl)naphthalene-1-carboxamide and N-(3-fluorophenyl)naphthalene-1-carboxamide showed against M.avium subsp. paratuberculosis two-fold higher activity than rifampicin and three-fold higher activity than ciprofloxacin. The most effective antimycobacterial compounds demonstrated insignificant toxicity against the human monocytic leukemia THP-1 cell line. The testing of biological activity of the compounds was completed with the study of photosynthetic electron transport (PET) inhibition in isolated spinach (Spinacia oleracea L.) chloroplasts. The PET-inhibiting activity expressed by IC₅₀ value of the most active compound N-[4-(trifluoromethyl)phenyl]naphthalene-1-carboxamide was 59 μmol/L. The structure-activity relationships are discussed.

Arylsulfonylamino-benzanilides as inhibitors of the apical sodium-dependent bile salt transporter (SLC10A2)

The apical sodium-dependent bile salt transporter (ASBT) plays a pivotal role in maintaining bile acid homeostasis. Inhibition of ASBT would reduce bile acid pool size and lower cholesterol levels. In this report, a series of novel arylsulfonylaminobenzanilides were designed and synthesized as potential inhibitors of ASBT. Most of them demonstrated great potency against ASBT’s bile acid transport activity. In particular, compound 5g₂ inhibited ASBT activity with an IC₅₀ value of 0.11 μM. These compounds represent potential cholesterol-lowering drugs.

Antitumor agents 290. Design, synthesis, and biological evaluation of new LNCaP and PC-3 cytotoxic curcumin analogs conjugated with anti-androgens

In our continuing study of curcumin analogs as potential anti-prostate cancer drug candidates, 15 new curcumin analogs were designed, synthesized and evaluated for cytotoxicity against two human prostate cancer cell lines, androgen-dependent LNCaP and androgen-independent PC-3. Twelve analogs (5-12, 15, 16, 19, and 20) are conjugates of curcumin (1) or methyl curcumin (2) with a flutamide- or bicalutamide-like moiety. Two compounds (22 and 23) are C4-mono- and difluoro-substituted analogs of dimethyl curcumin (DMC, 21). Among the newly synthesized conjugates compound 15, a conjugate of 2 with a partial bicalutamide moiety, was more potent than bicalutamide alone and essentially equipotent with 1 and 2 against both prostate tumor cell lines with IC(50) values of 41.8 μM (for LNCaP) and 39.1 μM (for PC-3). A cell morphology study revealed that the cytotoxicity of curcumin analogs or curcumin-anti-androgen conjugates detected from both prostate cancer cell lines might be due to the suppression of pseudopodia formation. A molecular intrinsic fluorescence experiment showed that 1 accumulated mainly in the nuclei, while conjugate 6 was distributed in the cytosol. At the tested conditions, anti-androgens suppressed pseudopodia formation in PC-3 cells, but not in LNCaP cells. The evidence suggests that distinguishable target proteins are involved, resulting in the different outcomes toward pseudopodia suppression.

Anilides and toluidides of 3beta-acetyloleanolic acid

Amide formation is one of the reactions that can be undertaken within the carboxyl group of oleanolic acid. A simple method for oleanolic acid anilide and toluidides synthesis is presented. The influence of the location of the methyl substituent on the reactivity of the amine group was tested and the "ortho effect" of the methyl substituent within the molecule of o-toluidine on the time of reaction was observed. The structures of the newly obtained compounds were determined by spectroscopic methods.

Synthesis and characterization of bicalutamide-loaded magnetic nanoparticles as anti-tumor drug carriers

This study examined the optical characteristics of bicalutamide-loaded magnetic/ethylene glycol composite nanoparticles (BMP), as well as their anti-cancer activity against cancer cells. The gamma-Fe2O3 magnetic nanoparticles (MNPs), approximately 20 nm in diameter, were prepared via a chemical co-precipitation method and coated with two surfactants to yield a water-based product. The characteristics of the particles were determined via X-ray diffraction (XRD), field emission scanning electron microscopy, and Raman spectrophotometry. The Raman spectra of the BMP showed peaks at 222, 283, 395, 520, 669 and 1316 cm(-1), with broadened band in comparison to the Raman spectra of the magnetic nanoparticles. The BMP absorbance evidenced a rapid increase, with a broad peak at 409 nm, thus reflecting a good loading of the bicalutamide onto the magnetic nanoparticles. The results of the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay showed that the MNPs were non-toxic against human brain cancer cells (SH-SY5Y), human cervical cancer cells (Hela), human liver cancer cells (HepG2), breast cancer cells (MCF-7), colon cancer cells (CaCO2) and human prostate cancers (Du 145, PC3) tested herein. In particular, BMPs were cytotoxic at 56% against DU145 cells, at 74.37% in SH-SY5Y cells, and at 58% in Hela cells. Our results demonstrated the biological applicability of BMP nanoparticles as anticancer agents and as agents for enhanced drug delivery against human prostate cancer cells. Our results indicated that the MNPs were biostable and that the BMP functioned effectively as drug delivery vehicles.

Design, synthesis and prostate cancer cell-based studies of analogs of the Rho/MKL1 transcriptional pathway inhibitor, CCG-1423

We recently identified bis(amide) CCG-1423 (1) as a novel inhibitor of RhoA/C-mediated gene transcription that is capable of inhibiting invasion of PC-3 prostate cancer cells in a Matrigel model of metastasis. An initial structure-activity relationship study focusing on bioisosteric replacement of the amides and conformational restriction identified two compounds, 4g and 8, with improved selectivity for inhibition of RhoA/C-mediated gene transcription and attenuated cytotoxicity relative to 1. Both compounds were also capable of inhibiting cell invasion with equal efficacy to 1 but with less attendant cytotoxicity.

Total synthesis of platensimycin and related natural products

Platensimycin is the flagship member of a new and growing class of antibiotics with promising antibacterial properties against drug-resistant bacteria. The total syntheses of platensimycin and its congeners, platensimycins B(1) and B(3), platensic acid, methyl platensinoate, platensimide A, homoplatensimide A, and homoplatensimide A methyl ester, are described. The convergent strategy developed toward these target molecules involved construction of their cage-like core followed by attachment of the various side chains through amide bond formation. In addition to a racemic synthesis, two asymmetric routes to the core structure are described: one exploiting a rhodium-catalyzed asymmetric cycloisomerization, and another employing a hypervalent iodine-mediated de-aromatizing cyclization of an enantiopure substrate. The final two bonds of the core structure were forged through a samarium diiodide-mediated ketyl radical cyclization and an acid-catalyzed etherification. The rhodium-catalyzed asymmetric reaction involving a terminal acetylene was developed as a general method for the asymmetric cycloisomerization of terminal enynes.

Synthesis and SAR of a novel positive allosteric modulator (PAM) of the metabotropic glutamate receptor 4 (mGluR4)

This Letter describes the synthesis and SAR of the novel positive allosteric modulator, VU0155041, a compound that has shown in vivo efficacy in rodent models of Parkinson's disease. The synthesis takes advantage of an iterative parallel synthesis approach to rapidly synthesize and evaluate a number of analogs of VU0155041.

Total synthesis of (-)-platensimycin, a novel antibacterial agent

An enantioselective synthesis of platensimycin, a novel antibiotic natural product that inhibits bacterial beta-ketoacyl-(acyl-carrier-protein) synthase (FabF), is described. Our synthetic strategy for the construction of the oxatetracyclic core involved an intramolecular Diels-Alder reaction. Our preliminary studies provided a complex tetracyclic product by first undergoing an interesting 1,5-hydride shift followed by a Diels-Alder reaction. Further optimization of the diene's electronic properties, by incorporation of a methoxy group, led to the oxatetracyclic core of platensimycin. The three required chiral centers, including two all-carbon quaternary chiral centers, were built in the intramolecular Diels-Alder step. The synthesis utilized natural (+)-carvone as the key chiral starting material, which determined the stereochemistry of the final product. The synthesis also featured an efficient Petasis olefination, a hydroboration sequence, a Gais's asymmetric Horner-Wadsworth-Emmons reaction, and a mercury salt catalyzed enol ether isomerization.

Preparation of chromophoric substrates for the glutamoyl specific staphylococcal protease

The synthesis of chromophoric substrates allowing an accurate determination of the staphylococcal protease activity is described. BOC-L-Glu-OPh, BOC-L-Phe-L-Glu-OPh, BOC-L-Ala-L-Glu-OPh, BOC-L-Ser-L-Glu-OPh and Z-L-Glu-pNA were prepared. Kinetic parameters of the staphyloccal protease-catalysed hydrolyses of these substrates are compared. In every case the dipeptide ester substrates lead to a lower catalytic efficiency (kcat/Km ratio), compared with either BOC-L-Glu-OPh or Z-L-Glu-OPh, mainly because of an increase in the Km value. Like other serine proteinases, the staphylococcal protease exhibits a high ratio of eeterase to peptidase activity, the kcat/Km ratio being 2.6 X 10(5)-fold higher with the Z-L-Glu-OPh than with the Z-L-Glu-pNA.

Antitumor activity of two derivatives from 2-acylamine-1, 4-naphthoquinone in mice bearing S180 tumor

Drugs containing a quinone moiety, such as anthracyclines, mitoxantrones and lapachol, show excellent anticancer activity. In this study, 2-butanoylamine-1,4-naphthoquinone (1) and 2-propanoylamine-1,4-naphthoquinone (2) derivatives from 2-amine-1 ,4-naphthoquinone were synthesized, and their antitumor activity in mice bearing Sarcoma 180 tumor were examined. In addition, hematology and biochemistry analyses, as well as, histopathological and morphological analyses were performed in order to evaluate the toxicological aspects of the naphthoquinones treatment. Both naphthoquinones showed potente antitumor activity. The inhibition rates were 33.48 and 42.35% for (1) and 37.65 and 55.24% for (2) at the dose of 25 and 50 mg/kg/day, respectively. In the histopathological analysis, the naphthoquinones showed only weak toxicity. Neither enzimatic activity of transaminases (aspartate aminotransferase-AST nor alanine aminotransferase-ALT), urea level nor hematological paramenter were significantly modified after naphthoquinones treatment. These data reinforce the anticancer potential of naphthoquinones derivatives.

Inhibitors of type III secretion in Yersinia: Design, synthesis and multivariate QSAR of 2-arylsulfonylamino-benzanilides

Compound 1, 2-(benzo[1,2,5]thiadiazole-4-sulfonylamino)-5-chloro-N-(3,4-dichloro-phenyl)-benzamide, was identified as a putative type III secretion inhibitor in Yersinia, and the compound thus has a potential to be used to prevent or treat bacterial infections. A set of seven analogues was synthesized and evaluated in a type III secretion dependent reporter-gene assay with viable bacterial to give basic SAR. A second set of 19 compounds was obtained by statistical molecular design in the building block and product space and by subsequent synthesis. Evaluation in the reporter-gene assay showed that the compounds ranged from non-active to compounds more potent than 1. Based on the data multivariate QSAR models were established and the final Hi-PLS model showed good correlation between experimentally determined % inhibition and the calculated % inhibition of the reporter-gene signal.

Potent 2′-aminoanilide inhibitors of cFMS as potential anti-inflammatory agents

A series of 2'-aminoanilides have been identified which exhibit potent and selective inhibitory activity against the cFMS tyrosine kinase. Initial SAR studies within this series are described which examine aroyl and amino group substitutions, as well as the introduction of hydrophilic substituents on the benzene core. Compound 47 inhibits the isolated enzyme (IC(50)=0.027 microM) and blocks CSF-1-induced proliferation of bone marrow-derived macrophages (IC(50)=0.11 microM) and as such, serves as a lead candidate for further optimization studies.

Enantioselective Synthesis of (−)-Platensimycin Oxatetracyclic Core by Using an Intramolecular Diels−Alder Reaction

An enantioselective route to the oxatetracyclic core of (-)-platensimycin (1) has been investigated by using an intramolecular Diels-Alder reaction as the key step. The thermal reaction of E/Z mixture (1:1) provided oxatetracyclic core 2 from the E-diene and the Z-diene was recovered unchanged. The Diels-Alder substrate was conveniently assembled in optically active form with use of (S)-carvone as the starting material.

Synthesis and SAR Investigations for Novel Melanin-Concentrating Hormone 1 Receptor (MCH1) Antagonists Part 1. The Discovery of Arylacetamides as Viable Replacements for the Dihydropyrimidinone Moiety of an HTS Hit

Melanin-concentrating hormone (MCH) is involved in the regulation of feeding, water balance, energy metabolism, general arousal and attention state, memory, cognitive functions, and psychiatric disorders. Herein, two new chemical series exemplified by N-[5-(1-{3-[2,2-bis-(4-fluoro-phenyl)-acetylamino]-propyl}-piperidin-4-yl)-2,4-difluoro-phenyl]-isobutyramide (SNAP 102739, 5m) and N-[3-(1-{3-[(S)-2-(4-fluoro-phenyl)-propionylamino]-propyl}-piperidin-4-yl)-4-methylphenyl]-isobutyramide ((S)-6b) are reported. These compounds were designed to improve the pharmacokinetic properties of the high-throughput screening lead compound 1 (SNAP 7941). The MCH1 receptor antagonists 5m and (S)-6b show reasonable pharmacokinetic profiles (rat bioavailability = 48 and 81%, respectively). Compounds 5m and (S)-6b demonstrated the inhibition of a centrally administered MCH-evoked drinking effect, and compound 5m exhibited oral in vivo efficacy in the rat social interaction model of anxiety, with a minimum effective dose = 0.3 mg/kg.

Design, Synthesis, and in Vivo SAR of a Novel Series of Pyrazolines as Potent Selective Androgen Receptor Modulators

A novel series of pyrazolines 2 have been designed, synthesized, and evaluated by in vivo screening as tissue-selective androgen receptor modulators (SARMs). Structure-activity relationships (SAR) were investigated at the R1 to R6 positions as well as the core pyrazoline ring and the anilide linker. Overall, strong electron-withdrawing groups at the R1 and R2 positions and a small group at the R5 and R6 position are optimal for AR agonist activity. The (S)-isomer of 7c exhibits more potent AR agonist activity than the corresponding (R)-isomer. (S)-7c exhibited an overall partial androgenic effect but full anabolic effect via oral administration in castrated rats. It demonstrated a noticeable antiandrogenic effect on prostate in intact rats with endogenous testosterone. Thus, (S)-7c is a tissue-selective nonsteroidal androgen receptor modulator with agonist activity on muscle and mixed agonist and antagonist activity on prostate.

An Expedient Enantioselective Strategy for the Oxatetracyclic Core of Platensimycin

An enantioselective route for the synthesis of oxatetracyclic core of platensimycin is reported for the first time using a 5-exo-trig cyclization followed by intramolecular etherification as key reactions. The requisite dienynone for the radical cyclization is synthesized in eight steps from the Wieland-Miescher ketone employing a Claisen rearrangement.

Formal synthesis of (+/-)-platensimycin

[reaction: see text] Reductive alkylation of 5-methoxy-1-tetralone (6) with 2,3-dibromopropene gave an equilibrium mixture of bicyclic diones 7 (51%) and 8 (35%). Radical cyclization of 7 afforded tricyclic dione 5 (84%), which was reduced, cyclized, and dehydrated to give tetracyclic alkene 13 in 63% yield. Allylic oxidation of 13 with SeO2 and activated MnO2 afforded enone 2 in 85% yield, thereby completing a short formal synthesis of (+/-)-platensimycin.

Synthesis and Biological Evaluation of Chiral α-Aminoanilides with Central Antinociceptive Activity

Tocainide and related optically active chiral alpha-aminoanilides were synthesized and tested in vivo via the hot plate test to evaluate their central analgesic action. The aims of the study were to verify if a) the increase in lipophilicity, obtained by the introduction of an alkyl group on the steric center (3f-i), and the replacement of the C=O group with the C=S (10) group as well as the introduction of a methyl or ethyl group on the amidic nitrogen atom (8a-c) would produce an increase in central analgesic efficacy with respect to Tocainide; b) the 2,6-xylidide moiety is crucial for high analgesic activity (3b-e); c) the hydrogen atom bonded to the amidic nitrogen moiety is an essential pharmacophoric element for analgesic activity. Among all the synthesized compounds, 3f showed antinociceptive properties with a good enantioselective index.

Design and synthesis of anticonvulsants from a combined phthalimide–GABA–anilide and hydrazone pharmacophore

Two series of pharmacophoric hybrids of phthalimide-GABA-anilides/hydrazones were designed and synthesized and evaluated for their anticonvulsant and neurotoxic properties. The structures of the synthesized compounds were confirmed by the use of their spectral data besides elemental analysis. Initial anticonvulsant screening was performed using intraperitoneal (i.p.) maximal electroshock-induced seizure (MES), subcutaneous pentylenetetrazole (scPTZ), subcutaneous strychnine (scSTY), and intraperitoneal picrotoxin (ipPIC)-induced seizure threshold tests. All of the compounds were ineffective in the MES test. Most of the compounds were found to be effective in the scSTY and ipPIC models and very few compounds showed protection in the scPTZ model.

Synthesis and Biological Evaluation of [18F]Bicalutamide, 4-[76Br]Bromobicalutamide, and 4-[76Br]Bromo-thiobicalutamide as Non-Steroidal Androgens for Prostate Cancer Imaging

Androgen receptors (AR) are overexpressed in most primary and metastatic prostate cancers. To develop a nonsteroidal AR-mediated imaging agent, we synthesized and radiolabeled several analogs of the potent antiandrogen bicalutamide: [18F]bicalutamide, 4-[76Br]bromobicalutamide, and [76Br]bromo-thiobicalutamide. Two of these analogs, 4-[76Br]bromobicalutamide and [76Br]bromo-thiobicalutamide, were found to have a substantially increased affinity for the androgen receptor (AR) compared to that of bicalutamide. The synthesis of [18F]bicalutamide utilized a pseudocarrier approach to effect addition of a carbanion generated from tracer-level amounts of a radiolabeled precursor to an unlabeled carbonyl precursor. 4-[76Br]Bromobicalutamide and [76Br]bromo-thiobicalutamide were labeled through electrophilic bromination of a tributylstannane precursor. The former could be prepared in high specific activity, and its tissue distribution was tested in vivo. Androgen target tissue uptake was evident in castrated adult male rats; however, in DES-treated, AR-positive, tumor-bearing male mice, tumor uptake was low.

Formal synthesis of (±)-platensimycin

A formal total synthesis of (+/-)-platensimycin [(+/-)-1] is reported involving an intramolecular Stetter reaction and a radical cyclization.

Synthesis of carbon-11 labeled sulfonanilide analogues as new potential PET agents for imaging of aromatase in breast cancer

Aromatase is a particularly good target in the treatment of estrogen receptor positive breast cancer. Novel carbon-11 labeled sulfonanilide analogues, N-[11C]methyl-N-(2-alkyloxy-4-nitrophenyl)-methanesulfonamides ([11C]3a-f, alkyl=propyl, isopropyl, 1-ethyl-propyl, cyclopentyl, cyclohexyl, and cyclohexylethyl), were designed and synthesized as potential PET agents for imaging of aromatase in breast cancer.