ABSTRACT
We designed and synthesized a new series of fatty acid synthase (FASN) inhibitors with potential utility for the treatment of cancer. Extensive SAR studies led to highly active FASN inhibitors with good cellular activity and oral bioavailability, exemplified by compound 34. Compound 34 is a potent inhibitor of human FASN (IC50â¯=â¯28â¯nM) that effectively inhibits proliferation of A2780 ovarian cells (IC50â¯=â¯13â¯nM) in lipid-reduced serum (LRS). This cellular activity can be rescued by addition of palmitate, consistent with an on-target effect. Compound 34 is also active in many other cell types, including PC3M (IC50â¯=â¯25â¯nM) and LnCaP-Vancouver prostate cells (IC50â¯=â¯66â¯nM), and is highly bioavailable (F 61%) with good exposure after oral administration. In a pharmacodynamics study in H460 lung xenograft-bearing mice, oral treatment with compound 34 results in elevated tumor levels of malonyl-CoA and decreased tumor levels of palmitate, fully consistent with the desired target engagement.
Subject(s)
Antineoplastic Agents/pharmacology , Drug Design , Enzyme Inhibitors/pharmacology , Fatty Acid Synthase, Type I/antagonists & inhibitors , Imidazoles/pharmacology , Animals , Antineoplastic Agents/administration & dosage , Antineoplastic Agents/chemical synthesis , Cell Proliferation/drug effects , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , Enzyme Inhibitors/administration & dosage , Enzyme Inhibitors/chemical synthesis , Fatty Acid Synthase, Type I/metabolism , Humans , Imidazoles/administration & dosage , Imidazoles/chemical synthesis , Mice , Models, Molecular , Molecular Structure , Neoplasms, Experimental/drug therapy , Neoplasms, Experimental/metabolism , Neoplasms, Experimental/pathology , Structure-Activity RelationshipABSTRACT
Shiga-like toxin (SLT)-producing Escherichia coli (SLTEC) is the leading cause of acute renal failure among children. SLTEC are most commonly ingested from contaminated food, and because cattle are a major reservoir, ground beef and milk have been a significant source of contamination associated with multiperson outbreaks. While serotype O157:H7 has been principally identified in the United States there are many other SLTEC serotypes associated with human disease. We have therefore examined the utility of an enzyme immunoassay (EIA) for Shiga-like toxins as a means of detecting the presence of low levels of multiple SLTEC serotypes in ground beef and milk. In the present study we demonstrated that it is possible to detect low levels (approximately 1 SLTEC per g of ground beef) in both small-scale (2 g of beef per 5 ml) and standard large-scale (25 g of beef per 225 ml) food microbial cultures. The EIA was also capable of allowing detection of SLTEC in nonspiked retail ground beef samples: we were able to recover SLTEC isolates (O113:Hu; O22:H-; O82:H8) from 3 of 12 ground beef samples. The EIA detected SLTs produced in spiked milk samples when as few as 1 SLTEC per ml was added. Overall the EIA proved to be a highly sensitive way to detect the presence of SLTEC in either ground beef or milk samples after overnight enrichment culturing in an appropriate broth and should provide a rapid and convenient method for the detection of multiple pathogenic SLTEC serotypes.
