The Future of Drug Development for Neglected Tropical Diseases: How the European Commission Can Continue to Make a Difference

In this article, the four coordinators of neglected tropical disease (NTD) drug development projects funded under the European Commission (EC) Framework Programme 7 argue that the EC should reassess their funding strategy to cover the steps necessary to translate a lead compound into a drug candidate for testing in clinical trials, and suggest ways in which this might be achieved

Structure-Based Optimization of a Non-\u3b2-lactam Lead Results in Inhibitors That Do Not Up-Regulate \u3b2-Lactamase Expression in Cell Culture

Bacterial expression of \u3b2-lactamases is the most widespread resistance mechanism to \u3b2 -lactam antibiotics. There is a pressing need for novel, non-\u3b2-lactam inhibitors of these enzymes. Our lead, compound 1, is chemically dissimilar to \u3b2 -lactams and is a noncovalent, competitive inhibitor of the enzyme. However, at 26 \u3bcM its activity is modest (Figure 1). Using the X-ray structure of the AmpC/1 complex as a template, 14 analogues were designed and synthesized. Among these, compound 10, had a Ki of 1 \u3bcM, 26-fold better than the lead. The structures of AmpC in complex with compound 10 and an analogue, compound 11, were determined by X-ray crystallography to 1.97 and 1.96 \uc5, respectively. Compound 10 was active in cell culture, reversing resistance to the third generation cephalosporin ceftazidime in bacterial pathogens expressing AmpC. In contrast to \u3b2-lactam-based inhibitors compound 10 did not up-regulate \u3b2-lactamase expression in cell culture but simply inhibited the enzyme expressed by the resistant bacteria. Its escape from this resistance mechanism derives from its dissimilarity to \u3b2 -lactam antibiotics

IL GIOCO MOLECOLARE TRA DRUG DISCOVERY E CHEMICAL BIOLOGY

La chemical biology \ue8 una disciplina vicina alla chimica farmaceutica strettamente connessa al processo di drug discovery mediante uno scambio di ruolo di inibitori/ligandi e probe molecolari. In tre esempi di applicazione della chemical biology-drug discovery vengono illustrati i linker per la bioconiugazione, le sonde fluorescenti in studi di interazione farmacorecettore cellulare (target engagement) e l\u2019indagine proteomica dei meccanismi biologici d\u2019azione di inibitori specifici

Feasibility Study on a Measurement Method and a Portable Measuring System to Estimate the Concentration of Cloxacillin and β -Lactamase in Milk

Antibiotics are nowadays used and abused worldwide in common veterinary practice to treat diseases, prevent infections, and promote animal's growth. Drug resistance occurrence is a relevant phenomenon that can inactivate the antibiotic. Moreover, antibiotics used for animals are also found in milk and it poses serious health risks to humans. Another negative effect is related to milk processors since antibiotics cause detrimental effects on cheese and yogurt starter bacteria. Given its consumption as both beverage and derivatives, milk is one of the most regulated products in food industry. Nowadays several commercial tests are available to investigate antibiotics in milk, but they generally provide a qualitative result, require bulky procedure, and are time consuming. In this paper, we investigate the use of a chromogenic cephalosporin to quantify the concentration of cloxacillin - a β-lactam difficult to be detected by using "cowside" screenings which is the drug of choice in the method of mastitis control. The proposed measurement method and prototype have been demonstrated to be able to detect cloxacillin in milk at concentrations lower than the MRL set by the European Commission. Moreover, they are also able to detect the illegal practice of using β-lactamase to degrade β-lactams in milk

Structure-based design and in-parallel synthesis of inhibitors of AmpC beta-lactamase

Background: Group I p-lactamases are a major cause of antibiotic resistance to beta -lactams such as penicillins and cephalosporins. These enzymes are only modestly affected by classic beta -lactam-based inhibitors, such as clavulanic acid. Conversely, small arylboronic acids inhibit these enzymes at sub-micromolar concentrations. Structural studies suggest these inhibitors bind to a well-defined cleft in the group I beta -lactamase AmpC; this cleft binds the ubiquitous R1 side chain of beta -lactams. Intriguingly, much of this cleft is left unoccupied by the small arylboronic acids. Results: To investigate if larger boronic acids might take advantage of this cleft, structure-guided in-parallel synthesis was used to explore new inhibitors of AmpC. Twenty-eight derivatives of the lead compound, 3-aminophenylboronic acid, led to an inhibitor with 80-fold better binding (2; K-i 83 nM). Molecular docking suggested orientations for this compound in the R1 cleft. Based on the docking results, 12 derivatives of 2 were synthesized, leading to inhibitors with iii values of 60 nM and with improved solubility. Several of these inhibitors reversed the resistance of nosocomial Gram-positive bacteria, though they showed little activity against Gram-negative bacteria. The X-ray crystal structure of compound 2 in complex with AmpC was subsequently determined to 2.1 Angstrom resolution. The placement of the proximal two-thirds of the inhibitor in the experimental structure corresponds with the docked structure, but a bond rotation leads to a distinctly different placement of the distal part of the inhibitor. In the experimental structure, the inhibitor interacts with conserved residues in the R1 cleft whose role in recognition has not been previously explored. Conclusions: Combining structure-based design with in-parallel synthesis allowed for the rapid exploration of inhibitor functionality in the R1 cleft of AmpC. The resulting inhibitors differ considerably from beta -lactams but nevertheless inhibit the enzyme well. The crystal structure of 2 (K-i 83 nM) in complex with AmpC may guide exploration of a highly conserved, largely unexplored cleft, providing a template for further design against AmpC beta -lactamase

\u201cA step further in the discovery of phthalein derivatives as Thymidylate Synthase inhibitors\u201d

Phenolphthalein (Pth) was discovered as a low micromolar inhibitor of the enzyme ThymidylateSynthase (TS), an important target for anticancer chemotherapy. In the present work, a newseries of Pth derivatives have been designed and synthesized. All the compounds have beencharacterized through NMR techniques. A set of twelve Pth derivatives has been tested againstthree TS enzymes and their bio-profiles obtained. The bio-profiling studies suggest that theinhibitory potency of the compounds has been improved of about fifty times againstLactobacillus casei TS (LcTS) and five times against humant TS (hTS) with respect to the lead.The most active compound shows an inhibition constant (Ki) of 70 nM against Escherichia coliTS (EcTS)