Discovery and optimization of cyclohexane-1,4-diamines as allosteric MALT1 inhibitors.

Inhibition of mucosa-associated lymphoid tissue lymphoma translocation protein-1 (MALT1) is a promising strategy to modulate NF-κB signaling, with the potential to treat B-cell lymphoma and autoimmune diseases. We describe the discovery and optimization of (1s,4s)-N,N'-diaryl cyclohexane-1,4-diamines, a novel series of allosteric MALT1 inhibitors, resulting in compound 8 with single digit micromolar cell potency. X-ray analysis confirms that this compound binds to an induced allosteric site in MALT1. Compound 8 is highly selective and has an excellent in vivo rat PK profile with low clearance and high oral bioavailability, making it a promising lead for further optimization.

Identification of unprecedented ATP-competitive choline kinase inhibitors.

In this article we describe the identification of unprecedented ATP-competitive ChoKα inhibitors starting from initial hit NMS-P830 that binds to ChoKα in an ATP concentration-dependent manner. This result is confirmed by the co-crystal structure of NMS-P830 in complex with Δ75-ChoKα. NMS-P830 is able to inhibit ChoKα in cells resulting in the reduction of intracellular phosphocholine formation. A structure-based medicinal chemistry program resulted in the identification of selective compounds that have good biochemical activity, solubility and metabolic stability and are suitable for further optimization. The ChoKα inhibitors disclosed in this article demonstrate for the first time the possibility to inhibit ChoKα with ATP-competitive compounds.

Chemoenzymatic Synthesis of Enantiomeric, Bicyclic δ-Halo-γ-lactones with a Cyclohexane Ring, Their Biological Activity and Interaction with Biological Membranes.

Starting from 1-acetyl-1-cyclohexene, three enantiomeric pairs (ee ≥99%) of bicyclic δ-halo-γ-lactones with cyclohexane ring were obtained in five-step synthesis. The key stereochemical steps were lipase-catalyzed kinetic resolution of racemic 1-(cyclohex-1-en-1-yl) ethanol followed by transfer of chirality to ethyl 2-(2-ethylidenecyclohexyl) acetate in the Johnson-Claisen rearrangement. Synthesized halolactones exhibited antiproliferative activity towards canine B-cell leukemia cells (GL-1) and canine B-cell chronic leukemia cells (CLB70) and the most potent (IC50 18.43 ± 1.46 µg/mL against GL-1, IC50 11.40 ± 0.40 µg/mL against CLB70) comparable with the control etoposide, was (1R,6R,1'S)-1-(1'-chloroethyl)-9- oxabicyclo[4.3.0]nonan-8-one (8b). All halolactones did not have a toxic effect on erythrocytes and did not change the fluidity of membranes in the hydrophobic region of the lipid bilayer. Only weak changes in the hydrophilic area were observed, like the degree of lipid packing and associated hydration. The racemic halolactones were also tested for their antimicrobial properties and found to exhibit selectivity towards bacteria, in particular, towards Proteus mirabilis ATCC 35659.

Discovery of a Potent and Selective CCR4 Antagonist That Inhibits Treg Trafficking into the Tumor Microenvironment.

Recruitment of suppressive CD4+ FOXP3+ regulatory T cells (Treg) to the tumor microenvironment (TME) has the potential to weaken the antitumor response in patients receiving treatment with immuno-oncology (IO) agents. Human Treg express CCR4 and can be recruited to the TME through the CC chemokine ligands CCL17 and CCL22. In some cancers, Treg accumulation correlates with poor patient prognosis. Preclinical data suggests that preventing the recruitment of Treg and increasing the population of activated effector T cells (Teff) in the TME can potentiate antitumor immune responses. We developed a novel series of potent, orally bioavailable small molecule antagonists of CCR4. From this series, several compounds exhibited high potency in distinct functional assays in addition to good in vitro and in vivo ADME properties. The design, synthesis, and SAR of this series and confirmation of its in vivo activity are reported.

Anticancer activity of newly synthesized 1,1-disubstituted cyclohexane-1-carboxamides: in vitro caspases mediated apoptosis activators in human cancer cell lines and their molecular modeling.

Novel 1,1-disubstituted cyclohexane-1-carboxamides 6a-h, 7a-e, and 8a-b were designed and synthesized as apoptotic inducers. Cytotoxicity test revealed that some compounds have strong to moderate effect, while others displayed weak action against different cancer cell lines including, MCF-7, HepG2, A549, and HTC-116. A549 carcinoma cell line exhibited higher sensitivity toward all synthesized candidates especially compounds 6a and 8a which offered the lowest IC50 values 3.03 and 5.21 µM, respectively, relative to the positive control doxorubicin with IC50 value of 3.01 µM. Compared to doxorubicin treatment, compounds 6a and 8a induced caspases-3, -8, and -9 activities and G2/M growth arrest in A549 carcinoma cell line. The expression levels of p53 (tumor suppressor protein that in humans is encoded by the TP53 gene), Bax (apoptosis regulator protein in humans that is encoded by bax gene), and the Bax/Bcl-2 ratio were all higher than those in doxorubicin-treated cells (Bcl-2, B-cell lymphoma 2, encoded in humans by the Bcl-2 gene). Additionally, compounds 6a and 8a appeared to exhibit higher selectivity against MCF-10 human breast normal cell line. The synthesized congeners could be considered as potent apoptotic inducers interfering with extrinsic and intrinsic apoptotic pathways. Moreover, compound 6a was able to form complex with zinc ions as indicated by UV spectrophotometry which revealed its ability for being caspase activator. Molecular docking studies expected the interactions and binding modes of the synthesized inhibitors in the caspase-3 active site.

Block Copolyesters Containing 2,5-Furan and trans-1,4-Cyclohexane Subunits with Outstanding Gas Barrier Properties.

Biopolymers are gaining increasing importance as substitutes for plastics derived from fossil fuels, especially for packaging applications. In particular, furanoate-based polyesters appear as the most credible alternative due to their intriguing physic/mechanical and gas barrier properties. In this study, block copolyesters containing 2,5-furan and trans-1,4-cyclohexane moieties were synthesized by reactive blending, starting from the two parent homopolymers: poly(propylene furanoate) (PPF) and poly(propylene cyclohexanedicarboxylate) (PPCE). The whole range of molecular architectures, from long block to random copolymer with a fixed molar composition (1:1 of the two repeating units) was considered. Molecular, thermal, tensile, and gas barrier properties of the prepared materials were investigated and correlated to the copolymer structure. A strict dependence of the functional properties on the copolymers' block length was found. In particular, short block copolymers, thanks to the introduction of more flexible cyclohexane-containing co-units, displayed high elongation at break and low elastic modulus, thus overcoming PPF's intrinsic rigidity. Furthermore, the exceptionally low gas permeabilities of PPF were further improved due to the concomitant action of the two rings, both capable of acting as mesogenic groups in the presence of flexible aliphatic units, and thus responsible for the formation of 1D/2D ordered domains, which in turn impart outstanding barrier properties.

Design, synthesis, and biological evaluation of lipophilically modified bisphenol Z derivatives.

In the present study, a small library of bisphenol Z (BPZ) derivatives was synthesized and investigated for anti-proliferative effects in cultured breast and glioblastoma cell lines. Synthesized BPZ derivatives varied in molecular size, polarity, and lipophilicity. Of the 8 derivatives tested, compounds 4 and 6, both of which displayed the highest degree of lipophilicity, were most active at inducing cell death as determined by the XTT assay. Cell membranes were interrogated using trypan blue staining and were shown to remain intact during treatments with 4 and 6. Activation of caspase enzymes (3 and/or 7) was noted to occur following treatment with compound 4. Polar BPZ derivatives, those with a substituted amine or alcohol, were devoid of any inhibitory or proliferative effects. The remaining derivatives seem to lack sufficient lipophilicity to execute an overt toxic effect. Our results suggest that increasing the lipophilic character of BPZ enhances the cytotoxic effects.

Synthesis, characterization, radiolabeling and biodistribution of a novel cyclohexane dioxime derivative as a potential candidate for tumor imaging.

PURPOSE: Dioxime derivative is reported to exhibit high affinity towards tumor cells. The objective of the present study is to synthesize a new dioxime derivative to be labeled with technetium-99m for using as a solid tumor marker. MATERIALS AND METHODS: ((2E,2',3E,3')-3,3'-(cyclohexane-1,2-diylbis (azanylylidene)) bis-(butan-2-one)dioxime) was synthesized by condensation of Butan-2,3-dione monooxime and diaminocyclohexane and labeled with 99mTc. The in-vivo distribution of the agent was studied by carrying out biodistribution in tumor bearing Albino mice. RESULTS: A new cyclohexane dioxime derivative was synthesized with a good yield of 93 ± 2% and its complexation with 99mTc was prepared with 85 ± 4% radiochemical yield under the optimized conditions and the preparation exhibited in-vitro stability up to 6 h. Biodistribution studies showed high uptake in tumor cells with T/NT (target to non-target ratio) = 3.4 ± 0.2 after 0.5 h post injection. CONCLUSION: As a result of biodistribution studies, the newly synthesized cyclohexane dioxime derivative showed its good uptake in tumor cells, which affords a potential radiopharmaceutical that could be used as a good tumor imaging agent.

Solution formulation development and efficacy of MJC13 in a preclinical model of castration-resistant prostate cancer.

MJC13, a novel FKBP52 targeting agent, has potential use for the treatment of castration-resistant prostate cancer. The purpose of this work was to develop a solution formulation of MJC13, and obtain its efficacy profile in a human prostate cancer xenograft mouse model. Preformulation studies were conducted to evaluate the physicochemical properties. Co-solvent systems were evaluated for aqueous solubility and tolerance. A human prostate cancer xenograft mouse model was established by growing 22Rv1 prostate cancer cells in C.B-17 SCID mice. The optimal formulation was used to study the efficacy of MJC13 in this preclinical model of castrate-resistant prostate cancer. We found that MJC13 was stable (at least for 1 month), highly lipophilic (logP = 6.49), poorly soluble in water (0.28 µg/mL), and highly plasma protein bound (>98%). The optimal formulation consisting of PEG 400 and Tween 80 (1:1, v/v) allowed us to achieve a MJC13 concentration of 7.5 mg/mL, and tolerated an aqueous environment. After twice weekly intratumoral injection with 10 mg/kg MJC13 in this formulation for four consecutive weeks, tumor volumes were significantly reduced compared to vehicle-treated controls.

Structure-guided discovery of 2-aryl/pyridin-2-yl-1H-indole derivatives as potent and selective hepsin inhibitors.

Hepsin, a type II transmembrane serine protease, is upregulated in prostate cancer and known to be involved in the progression of metastasis. Here we report a structure-guided approach, which resulted in the discovery of 2-aryl/pyridin-2-yl-1H-indole derivatives as potent and selective inhibitors of hepsin. Potent and selective inhibition of hepsin by compound 8 is likely due to interactions of the amidine group at the S1 site with the cyclohexyl ring from the 2-aryl group projecting towards the S1' site and the tert-hydroxyl group interacting with His57 side-chain as revealed by X-ray crystallography. Compounds 8 and 10, showed Ki of 0.1 µM for hepsin, and exhibited inhibition of invasion and migration of hepsin-overexpressing cell line. Compounds described here could serve as useful tool reagents to investigate the role of hepsin as a potential therapeutic target in cancer.

Synthesis of locked cyclohexene and cyclohexane nucleic acids (LCeNA and LCNA) with modified adenosine units.

We describe here the preparation of conformationally locked cyclohexane nucleic acids designed as hybrids between locked nucleic acids (LNAs) and cyclohexene nucleic acids (CeNAs), both of which excel in hybridization with complementary RNAs. We have accomplished the synthesis of these adenine derivatives starting from a simple ketoester and installed all four chiral centres by means of total synthesis. The acquired monomers were incorporated into nonamer oligonucleotides.

Effect of novel cyclohexane diester and benzene diester derivatives on melanogenesis.

In order to investigate potent whitening agents, we synthesized 15 cyclohexane diester derivatives and 15 benzene diester derivatives. To evaluate their structure-cytotoxicity relationships, we performed cell cytotoxicity tests on B16F10 mouse melanoma cells. To understand their whitening effects, melanin synthesis inhibitory activities in B16F10 cells and mushroom tyrosinase inhibitory activities were performed. In most cases, cell cytotoxicity was observed to be lower in 1,3-diester than in 1,2- and 1,4-diesters; when it came to the structural isomer of the side chain, all derivatives except the 1,2-cyclohexane diester derivatives showed lower cell cytotoxicity in the branch type of the side chain than in the linear type. Among the compounds evaluated, the compounds cyclohexane-1,3-diyl bis(decanoate), cyclohexane-1,4-diyl dioctanoate, and 1,3-phenylene bis (2-ethylhexanoate) emerged as potent melanin synthesis inhibitors. Our goal was to determine the expression levels of proteins involved in melanogenesis, Western blotting and RT-PCR showing that these compounds decreased tyrosinase, TRP-1, and TRP-2 while demonstrating significantly low cytotoxicity.

Structure-guided discovery of 1,3,5 tri-substituted benzenes as potent and selective matriptase inhibitors exhibiting in vivo antitumor efficacy.

Matriptase is a serine protease implicated in cancer invasion and metastasis. Expression of matriptase is frequently dysregulated in human cancers and matriptase has been reported to activate latent growth factors such as hepatocyte growth factor/scatter factor, and proteases such as urokinase plasminogen activator suggesting that matriptase inhibitors could have therapeutic potential in treatment of cancer. Here we report a structure-based approach which led to the discovery of selective and potent matriptase inhibitors with benzene as central core having 1,3,5 tri-substitution pattern. X-ray crystallography of one of the potent analogs in complex with matriptase revealed strong hydrogen bonding and salt-bridge interactions in the S1 pocket, as well as strong CH-π contacts between the P2/P4 cyclohexyl and Trp215 side-chain. An additional interaction of the pendant amine at cyclohexyl with Gln175 side-chain results in substantial improvement in matriptase inhibition and selectivity against other related serine proteases. Compounds 15 and 26 showed tumor growth inhibition in a subcutaneous DU-145 prostate cancer mouse model. These compounds could be useful as tools to further explore the biology of matriptase as a drug target.

Synthesis and antiproliferative activity of ligerin and new fumagillin analogs against osteosarcoma.

Ligerin (1) is a natural chlorinated merosesquiterpenoid related to fumagillin (2) exhibiting a selective antiproliferative activity against osteosarcoma cell lines and an in vivo antitumor activity in a murine model. Semisynthesis of ligerin analogs was performed in order to study the effects of the C3-spiroepoxide substitution by a halogenated moiety together with the modulation of the C6 chain. Results showed that all derivatives exhibited an in vitro antiproliferative activity against osteosarcoma cell lines and that chlorohydrin compounds were equally or more active than their spiroepoxy analogs. Among semisynthetic analogs, the parent compound 1 was the best candidate for further studies since it exhibited higher or equivalent activity compared to TNP470 (3) against SaOS2 and MG63 human osteosarcoma cells with a four times weaker toxicity against HFF2 human fibroblasts. Quantitative videomicroscopy analysis was conducted and allowed a better understanding of the mechanism of its antiproliferative activity.

Design, synthesis and evaluation of a cellular stable and detectable biotinylated fumagillin probe and investigation of cell permeability of fumagillin and its analogs to endothelial and cancer cells.

Fumagillin (1), a natural product of fungal origin, and its analogs were discovered to be extremely potent and highly selective inhibitors restraining endothelial cell proliferation in vitro by covalently binding to MetAP2. In order to further understand the unclear biological mechanisms and pharmacological processes of fumagillin and its derivatives, fumagillin-biotin conjugate 8 was designed and synthesized, which is linked with a 27-atom connection chain and by urethane (carbamate) bonds between fumagillol and D-norbiotinamine. The conjugate 8 shows comparable activity and selectivity against HUVEC proliferation as fumagillin. It was demonstrated that the conjugate 8 is stable inside the cell and its linker is of a suitable length for the detection of biotin in native and denatured conditions. Using the conjugate 8, it was determined that the cell permeability of fumagillin (1) and its analogs are not responsible for their inhibitory activity difference against the proliferation of endothelial and cancer cells. Furthermore, we confidently believe that our present strategy is a versatile and convenient method for investigating drug's cell permeability along with other studies regardless of reversible or irreversible interaction between the drug and binding target/s.

A novel class of substituted spiro [quinazoline-2,1'-cyclohexane] derivatives as effective PPAR-1 inhibitors: molecular modeling, synthesis, cytotoxic and enzyme assay evaluation.

Molecular docking simulation study was carried out to design a novel series of spiro [(2H, 3H)quinazoline-2,1'-cyclohexan]-4(1H)-one derivatives as a new class of effective PARP-1 inhibitors. Spiro [2H-3,1-benzoxazine-2,1'-cyclohexan]-4(1H)-one (5) was the starting compound to synthesize the target proposed analogues. The derivatives that showed the top scores and had the best fitting in the binding sites of the target protein were selected to evaluate their in vitro anti-proliferative activity against the cultured human breast carcinoma cell line (MCF-7) using doxorubicin as a standard drug. Additionally, the compounds that exhibited the highest cytotoxic efficiency were further subjected to PARP-1 enzyme assay taking 3-aminobenzamide as the reference drug. The structures of the novel derivatives were confirmed on the bases of microanalytical and spectral data.

Design of a highly selective and potent class of non-planar estrogen receptorâ€ ß agonists.

Selective activation of the estrogen receptorâ€…ß (ERß) could be a safe approach to hormone replacement therapy for both women and men, in contrast to the estrogens currently used for women which activate both ERß and ERα, occasionally causing severe side effects. The selective ERß agonist AC-131 has shown efficacy in animal models of Parkinson's disease and neuropathic pain. With the use of AC-131 as template, herein we report the discovery, synthesis, and structure-activity relationship (SAR) study of a new class of dihydrobenzofurans as potent and selective ERß agonists. The SAR was established by enantioselective synthesis, molecular modeling, and whole-cell-based functional assays. The most potent diastereomer, cis-10-SR, was shown to have an EC50 value of <1 nM, potency 100-fold higher than that of AC-131. Even more interestingly, compound trans-10-SS exhibited 1000-fold ERß/ERα selectivity while still maintaining good potency (∼10 nM). In addition, trans-10-SS showed only partial agonist activity (30-60 % Eff.) toward ERα at 10 µM. This unprecedented selectivity could be rationalized by molecular modeling. Compound trans-10-SS appears to be the first molecule to take advantage of both conservative amino acid differences found in the α- and ß-faces of the binding cavities of ERα and ERß.

Discovery of potent inhibitors of human and mouse fatty acid amide hydrolases.

Fatty acid amide hydrolase (FAAH, EC 3.5.1.99) is the main enzyme catabolizing endocannabinoid fatty acid amides. FAAH inactivation promotes beneficial effects upon pain and anxiety without the side effects accompanying agonists of type-1 cannabinoid receptors. Aiming at discovering new selective FAAH inhibitors, we developed a series of compounds (5a-u) characterized by a functionalized heteroaromatic scaffold. Particularly, 5c and 5d were identified as extremely potent, noncompetitive, and reversible FAAH inhibitors endowed with a remarkable selectivity profile and lacking interaction with the hERG channels. In vivo antinociceptive activity was demonstrated for 5c, 5d, and 5n at a dose much lower than that able to induce either striatal and limbic stereotypies or anxiolytic activity, thus outlining their potential to turn into optimum preclinical candidates. Aiming at improving pharmacokinetic properties and metabolic stability of 5d, we developed a subset of nanomolar dialyzable FAAH inhibitors (5v-z), functionalized by specific polyethereal lateral chains and fluorinated aromatic rings.

Borylene transfer from an iron bis(borylene) complex: synthesis of 1,4-diboracyclohexadiene and 1,4-dibora-1,3-butadiene complexes.

Diene to be made: By tuning the size of acetylenic substituents, 1,4-diboracyclohexadiene and unprecedented 1,4-dibora-1,3-butadiene complexes were generated in a controlled manner by borylene transfer from an iron bis(borylene) complex to alkynes (see scheme).

Cytotoxic effects of combination of oxidosqualene cyclase inhibitors with atorvastatin in human cancer cells.

Ten oxidosqualene cyclase inhibitors with high efficacy as cholesterol-lowering agents and of different chemical structure classes were evaluated as potential anticancer agents against human cancer cells from various tissue origins and nontumoral human-brain-derived endothelial cells. Inhibition of cancer cell growth was demonstrated at micromolar concentrations, comparable to the concentrations of statins necessary for antitumor effect. Human glioblastoma cells were among the most sensitive cells. These compounds were also able to decrease the proliferation of angiogenic brain-derived endothelial cells, as a model of tumor-induced neovasculation. Additive effects in human glioblastoma cells were also demonstrated for oxidosqualene cyclase inhibitors in combination with atorvastatin while maintaining selectivity against endothelial cells. Thus, not only statins targeting the 3-hydroxy-3-methylglutaryl coenzyme A reductase but also inhibitors of oxidosqualene cyclase decrease tumor growth, suggesting new therapeutic opportunities of combined anti-cholesterol agents for dual treatment of glioblastoma.