Comparison of Proteomic Responses as Global Approach to Antibiotic Mechanism of Action Elucidation.

New antibiotics are urgently needed to address the mounting resistance challenge. In early drug discovery, one of the bottlenecks is the elucidation of targets and mechanisms. To accelerate antibiotic research, we provide a proteomic approach for the rapid classification of compounds into those with precedented and unprecedented modes of action. We established a proteomic response library of Bacillus subtilis covering 91 antibiotics and comparator compounds, and a mathematical approach was developed to aid data analysis. Comparison of proteomic responses (CoPR) allows the rapid identification of antibiotics with dual mechanisms of action as shown for atypical tetracyclines. It also aids in generating hypotheses on mechanisms of action as presented for salvarsan (arsphenamine) and the antirheumatic agent auranofin, which is under consideration for repurposing. Proteomic profiling also provides insights into the impact of antibiotics on bacterial physiology through analysis of marker proteins indicative of the impairment of cellular processes and structures. As demonstrated for trans-translation, a promising target not yet exploited clinically, proteomic profiling supports chemical biology approaches to investigating bacterial physiology.

Design of N-substituted amino caproic hydroxamic acid histone deacetylase inhibitors reveal an essential role for cap atomic composition.

A series of N-substituted amino caproic hydroxamic acid histone deacetylase inhibitors derivatives was designed in good-toexcellent yields and evaluated for their antiproliferative activity in a panel of human cancer cell lines, showing half maximum effective concentration varying from 700 nM to > 100 µM. Interestingly, the replacement of a furyl group by a thienyl one impacted very significantly the cap role on this antiproliferative activity and on histone acetylation induced by these drugs in cell-based but also in cell-free enzyme assays, suggesting an important role of the electronic density attached to the oxygen or sulfur atoms.

Therapeutic potential of cationic steroid antibacterials.

Antibiotics were one of the great health successes of the 20th century. Antibiotics, both naturally derived and synthetic, have resulted in huge decreases in both morbidity and mortality from bacterial infections. As a consequence, the 'antibiotic age' has changed public expectations about the results of infectious disease. However, this has led to high levels of inappropriate prescribing, where antibiotics may be administered to fulfil patient expectations rather than for clinical benefit. Along with unwise uses in agriculture and elsewhere, this has contributed to recent rises in numbers of antibiotic-resistant bacteria. As a result, many commentators have described this as the end of the antibiotic age and the term 'superbug' has entered the common vocabulary for multi-drug-resistant bacteria such as vancomycin-resistant Enterococcus, multi-drug-resistant Staphylococcus aureus and multi-drug-resistant Pseudomonas aeruginosa. In this context, an attractive approach for the development of antibacterial agents is the use of a new class of cationic steroidal compounds mimicking polymyxin activities. The permeabilization properties of these agents of the outer membranes of Gram-negative bacteria are reported in this review, as well as a discussion of literature results.