Stuart P. McElroy

The drug molecule PTC124 (Ataluren) has been described as a read-through agent, capable of suppressing premature termination codons (PTCs) and restoring functional protein production from genes disrupted by nonsense mutations. Following the discovery of PTC124 there was some controversy regarding its mechanism of action with two reports attributing its activity to an off-target effect on the Firefly luciferase (FLuc) reporter used in the development of the molecule. Despite questions remaining as to its mechanism of action, development of PTC124 continued into the clinic and it is being actively pursued as a potential nonsense mutation therapy. To thoroughly test the ability of PTC124 to read through nonsense mutations, we conducted a detailed assessment comparing the efficacy of PTC124 with the classical aminoglycoside antibiotic read-through agent geneticin (G418) across a diverse range of in vitro reporter assays. We can confirm the off-target FLuc activity of PTC124 but found that, while G418 exhibits varying activity in every read-through assay, there is no evidence of activity for PTC124.

N-Myristoyltransferase (NMT) represents a promising drug target for human African trypanosomiasis (HAT), which is caused by the parasitic protozoa Trypanosoma brucei. We report the optimization of a high throughput screening hit (1) to give a lead molecule DDD85646 (63), which has potent activity against the enzyme (IC(50) = 2 nM) and T. brucei (EC(50) = 2 nM) in culture. The compound has good oral pharmacokinetics and cures rodent models of peripheral HAT infection. This compound provides an excellent tool for validation of T. brucei NMT as a drug target for HAT as well as a valuable lead for further optimization.

A new series of NSAIDs in which aspirin is joined by an ester linkage to furoxan moieties, with different ability to release NO, were synthesized and tested for NO-releasing, antiinflammatory, antiaggregatory, and ulcerogenic properties. Related furazan derivatives, aspirin, its propyl ester, and its gamma-nitrooxypropyl ester were taken as references. All the products described present an antiinflammatory trend, maximized in derivatives 12, 16, and 17, they are devoid of acute gastrotoxicity, principally due to their ester nature, and show an antiplatelet activity primarily determined by their ability to release NO. They do not behave as aspirin prodrugs in human serum.