Gene expression analysis in rats treated with experimental acetyl-coenzyme A carboxylase inhibitors suggests interactions with the peroxisome proliferator-activated receptor alpha pathway.

Acetyl CoA carboxylase (ACC) 2, which catalyzes the carboxylation of acetyl-CoA to form malonyl-CoA, has been identified as a potential target for type 2 diabetes and obesity. Small-molecule inhibitors of ACC2 would be expected to reduce de novo lipid synthesis and increase lipid oxidation. Treatment of ob/ob mice with compound A-908292 (S) ({(S)-3-[2-(4-isopropoxy-phenoxy)-thiazol-5-yl]-1-methyl-prop-2-ynyl}-carbamic acid methyl ester), a small-molecule inhibitor with an IC(50) of 23 nM against ACC2, resulted in a reduction of serum glucose and triglyceride levels. However, compound A-875400 (R) ({(R)-3-[2-(4-isopropoxy-phenoxy)-thiazol-5-yl]-1-methyl-prop-2-ynyl}-carbamic acid methyl ester), an inactive enantiomer of A-908292 (S) with approximately 50-fold less activity against ACC2, also caused a similar reduction in glucose and triglycerides, suggesting that the glucose-lowering effects in ob/ob mice may be mediated by other metabolic pathways independent of ACC2 inhibition. To characterize the pharmacological activity of these experimental compounds at a transcriptional level, rats were orally dosed for 3 days with either A-908292 (S) or A-875400 (R), and gene expression analysis was performed. Gene expression analysis of livers showed that treatment with A-908292 (S) or A-875400 (R) resulted in gene expression profiles highly similar to known peroxisome proliferator-activated receptor (PPAR)-alpha activators. The results suggest that, in vivo, both A-908292 (S) and A-875400 (R) stimulated the PPAR-alpha-dependent signaling pathway. These results were further supported by both an in vitro genomic evaluation using rat hepatocytes and immunohistochemical evaluation using 70-kDa peroxisomal membrane protein. Overall, the gene expression analysis suggests a plausible mechanism for the similar pharmacological findings with active and inactive enantiomers of an ACC2 inhibitor.

N-{3-[2-(4-alkoxyphenoxy)thiazol-5-yl]-1-methylprop-2-ynyl}carboxy derivatives as acetyl-coA carboxylase inhibitors--improvement of cardiovascular and neurological liabilities via structural modifications.

A preliminary safety evaluation of ACC2 inhibitor 1-(S) revealed serious neurological and cardiovascular liabilities of this chemotype. A systematic structure-toxicity relationship study identified the alkyne linker as the key motif responsible for these adverse effects. Toxicogenomic studies in rats showed that 1-(R) and 1-(S) induced gene expression patterns similar to that seen with several known cardiotoxic agents such as doxorubicin. Replacement of the alkyne with alternative linker groups led to a new series of ACC inhibitors with drastically improved cardiovascular and neurological profiles.

The synthesis and structure-activity relationship studies of selective acetyl-CoA carboxylase inhibitors containing 4-(thiazol-5-yl)but-3-yn-2-amino motif: polar region modifications.

The structure-activity relationship study focused on the polar region of the HTS hit A-80040 (1) producing several series of potent and selective ACC2 inhibitors. The SAR suggests a compact lipophilic pocket that does not tolerate polar and ionic groups. Replacement of the hydroxyurea group with isoxazoles improves ACC2 selectivity while maintaining potency. Variations at the propargylic site of 11a reduce ACC2 potency.

Novel antibacterial class: a series of tetracyclic derivatives.

We describe the synthesis and antibacterial activity of a series of tetracyclic naphthyridones. The members of this series act primarily via inhibition of bacterial translation and belong to the class of novel ribosome inhibitors (NRIs). In this paper we explore the structure-activity relationships (SAR) of these compounds to measure their ability both to inhibit bacterial translation and also to inhibit the growth of bacterial cells in culture. The most active of these compounds inhibit Streptococcus pneumoniae translation at concentrations of <5 microM and have minimum inhibitory concentrations (MICs) of <8 microg/mL against clinically relevant strains of bacteria.

Synthesis and structure-activity relationships of N-{3-[2-(4-alkoxyphenoxy)thiazol-5-yl]-1- methylprop-2-ynyl}carboxy derivatives as selective acetyl-CoA carboxylase 2 inhibitors.

A structurally novel acetyl-CoA carboxylase (ACC) inhibitor is identified from high-throughput screening. A preliminary structure-activity relationship study led to the discovery of potent dual ACC1/ACC2 and ACC2 selective inhibitors against human recombinant ACC1 and ACC2. Selective ACC2 inhibitors exhibited IC50<20 nM and >1000-fold selectivity against ACC1. (S)-Enantiomer 9p exhibited high ACC2 activity and lowered muscle malonyl-CoA dose-dependently in acute rodent studies, whereas (R)-enantiomer 9o was weak and had no effect on the malonyl-CoA level.

Naphthamidine urokinase plasminogen activator inhibitors with improved pharmacokinetic properties.

A series of non-amide-linked 6-substituted-2-naphthamidine urokinase plasminogen activator (uPA) inhibitors are described. These compounds possess excellent binding activities and selectivities with significantly improved pharmacokinetic profiles versus previously described amide-linked inhibitors.

Interaction with the S1 beta-pocket of urokinase: 8-heterocycle substituted and 6,8-disubstituted 2-naphthamidine urokinase inhibitors.

Several 8-substituted 2-naphthamidine-based inhibitors of the serine protease urokinase plasminogen activator (uPA) are described. Direct attachment of five-membered saturated or unsaturated rings improved inhibitor performance; substitution with sulfones further improved binding profiles. Combination of these substituents or of previously described NH-linked heteroaromatic rings with 6-phenyl amide substituents provided further enhancements to potency and selectivity.

Novel inhibitors of bacterial protein synthesis: structure-activity relationships for 1,8-naphthyridine derivatives incorporating position 3 and 4 variants.

Structure-activity relationships for a recently discovered novel ribosome inhibitor (NRI) class of antibacterials were investigated. Preliminary efforts to optimize protein synthesis inhibitory activity of the series through modification of positions 3 and 4 of the naphthyridone lead template resulted in the identification of several biochemically potent analogues. A lack of corresponding whole cell antibacterial activity is thought to be a consequence of poor cellular penetration as evidenced by the enhancement of activity observed for a lead analogue tested in the presence of a cell permeabilizing agent.

Identification of novel binding interactions in the development of potent, selective 2-naphthamidine inhibitors of urokinase. Synthesis, structural analysis, and SAR of N-phenyl amide 6-substitution.

The preparation and assessment of biological activity of 6-substituted 2-naphthamidine inhibitors of the serine protease urokinase plasminogen activator (uPA, or urokinase) is described. 2-Naphthamidine was chosen as a starting point based on synthetic considerations and on modeling of substituent vectors. Phenyl amides at the 6-position were found to improve binding; replacement of the amide with other two-atom linkers proved ineffective. The phenyl group itself is situated near the S1' subsite; substitutions off of the phenyl group accessed S1' and other distant binding regions. Three new points of interaction were defined and explored through ring substitution. A solvent-exposed salt bridge with the Asp60A carboxylate was formed using a 4-alkylamino group, improving affinity to K(i) = 40 nM. Inhibitors also accessed two hydrophobic regions. One interaction is characterized by a tight hydrophobic fit made with a small dimple largely defined by His57 and His99; a weaker, less specific interaction involves alkyl groups reaching into the broad prime-side protein binding region near Val41 and the Cys42-Cys58 disulfide, displacing water molecules and leading to small gains in activity. Many inhibitors accessed two of these three regions. Affinities range as low as K(i) = 6 nM, and many compounds had K(i) < 100 nM, while moderate to excellent selectivity was gained versus four of five members of a panel of relevant serine proteases. Also, some selectivity against trypsin was generated via the interaction with Asp60A. X-ray structures of many of these compounds were used to inform our inhibitor design and to increase our understanding of key interactions. In combination with our exploration of 8-substitution patterns, we have identified a number of novel binding interactions for uPA inhibitors.

Novel antibacterial class.

We report the discovery and characterization of a novel ribosome inhibitor (NRI) class that exhibits selective and broad-spectrum antibacterial activity. Compounds in this class inhibit growth of many gram-positive and gram-negative bacteria, including the common respiratory pathogens Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, and Moraxella catarrhalis, and are nontoxic to human cell lines. The first NRI was discovered in a high-throughput screen designed to identify inhibitors of cell-free translation in extracts from S. pneumoniae. The chemical structure of the NRI class is related to antibacterial quinolones, but, interestingly, the differences in structure are sufficient to completely alter the biochemical and intracellular mechanisms of action. Expression array studies and analysis of NRI-resistant mutants confirm this difference in intracellular mechanism and provide evidence that the NRIs inhibit bacterial protein synthesis by inhibiting ribosomes. Furthermore, compounds in the NRI series appear to inhibit bacterial ribosomes by a new mechanism, because NRI-resistant strains are not cross-resistant to other ribosome inhibitors, such as macrolides, chloramphenicol, tetracycline, aminoglycosides, or oxazolidinones. The NRIs are a promising new antibacterial class with activity against all major drug-resistant respiratory pathogens.