ABSTRACT
Overexpression of AKT has an antiapoptotic effect in many cell types, and expression of dominant negative AKT blocks the ability of a variety of growth factors to promote survival. Therefore, inhibitors of AKT kinase activity might be useful as monotherapy for the treatment of tumors with activated AKT. Herein, we describe our lead optimization studies culminating in the discovery of compound 3g (GSK690693). Compound 3g is a novel ATP competitive, pan-AKT kinase inhibitor with IC 50 values of 2, 13, and 9 nM against AKT1, 2, and 3, respectively. An X-ray cocrystal structure was solved with 3g and the kinase domain of AKT2, confirming that 3g bound in the ATP binding pocket. Compound 3g potently inhibits intracellular AKT activity as measured by the inhibition of the phosphorylation levels of GSK3beta. Intraperitoneal administration of 3g in immunocompromised mice results in the inhibition of GSK3beta phosphorylation and tumor growth in human breast carcinoma (BT474) xenografts.
Subject(s)
Oxadiazoles/pharmacology , Protein Kinase Inhibitors/pharmacology , Proto-Oncogene Proteins c-akt/antagonists & inhibitors , Animals , Female , Magnetic Resonance Spectroscopy , Mass Spectrometry , Mice , Mice, SCID , Models, Molecular , Oxadiazoles/chemistry , Oxadiazoles/metabolism , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Substrate SpecificityABSTRACT
A novel benzylidenethiazolidinedione has been discovered with antimicrobial activity. Here, we present the results of a structure-activity study on this compound with respect to its antimicrobial activity.
Subject(s)
Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/pharmacology , Benzyl Compounds/chemical synthesis , Benzyl Compounds/pharmacology , Thiazolidinediones/chemical synthesis , Thiazolidinediones/pharmacology , Enterococcus faecalis/drug effects , Gram-Negative Bacteria/drug effects , Indicators and Reagents , Microbial Sensitivity Tests , Staphylococcus aureus/drug effects , Streptococcus pneumoniae/drug effects , Structure-Activity RelationshipABSTRACT
In our continuing efforts to identify small molecule vitronectin receptor antagonists, we have discovered a series of phenylbutyrate derivatives, exemplified by 16, which have good potency and excellent oral bioavailability (approximately 100% in rats). This new series is derived conceptually from opening of the seven-membered ring of SB-265123.
Subject(s)
Integrin alphaVbeta3/antagonists & inhibitors , Phenylbutyrates/pharmacology , Phenylbutyrates/pharmacokinetics , Acetates/chemistry , Administration, Oral , Aminopyridines/chemistry , Animals , Biological Availability , Cell Adhesion/drug effects , Cell Line , Half-Life , Humans , Phenylbutyrates/chemistry , RatsABSTRACT
Bacterial enoyl-acyl carrier protein (ACP) reductase (FabI) catalyzes the final step in each elongation cycle of bacterial fatty acid biosynthesis and is an attractive target for the development of new antibacterial agents. High-throughput screening of the Staphylococcus aureus FabI enzyme identified a novel, weak inhibitor with no detectable antibacterial activity against S. aureus. Iterative medicinal chemistry and X-ray crystal structure-based design led to the identification of compound 4 [(E)-N-methyl-N-(2-methyl-1H-indol-3-ylmethyl)-3-(7-oxo-5,6,7,8-tetrahydro-1,8-naphthyridin-3-yl)acrylamide], which is 350-fold more potent than the original lead compound obtained by high-throughput screening in the FabI inhibition assay. Compound 4 has exquisite antistaphylococci activity, achieving MICs at which 90% of isolates are inhibited more than 500 times lower than those of nine currently available antibiotics against a panel of multidrug-resistant strains of S. aureus and Staphylococcus epidermidis. Furthermore, compound 4 exhibits excellent in vivo efficacy in an S. aureus infection model in rats. Biochemical and genetic approaches have confirmed that the mode of antibacterial action of compound 4 and related compounds is via inhibition of FabI. Compound 4 also exhibits weak FabK inhibitory activity, which may explain its antibacterial activity against Streptococcus pneumoniae and Enterococcus faecalis, which depend on FabK and both FabK and FabI, respectively, for their enoyl-ACP reductase function. These results show that compound 4 is representative of a new, totally synthetic series of antibacterial agents that has the potential to provide novel alternatives for the treatment of S. aureus infections that are resistant to our present armory of antibiotics.