SBIR-STTR Award

The objective of this six-month Phase I SBIR proposal is to develop a new class of antibiotics based on inhibiting the bacterial DNA adenine methyltransferase. DNA methylation plays a critical role in the virulence of some bacteria, including E. coli and Salmonella typhimurium. Removing the enzyme by genetic means was shown to decrease virulence over 10,000 fold in animals. These results provide clear validation of this enzyme as a drug target. Humans lack this type of DNA methylation; thus, small molecules that inhibit the bacterial enzyme are likely to be selective. EpiGenX Pharmaceuticals now has an equipped lab that is engaged in discovering cancer therapeutics aimed at the mammalian DNA methyltransferase. A similar strategy is proposed here for E.coli DAM: high throughput fluorescence-based screens using purified E.coli DAM and two historical libraries. Using this strategy we have identified several potent inhibitors of the enzyme. We propose to use computational methods to facilitate our efforts to select the most potent compounds in the two historical libraries. Realization of the objective provides EpiGenX with a clear path for antibiotic optimization through more sophisticated focused combinatorial libraries, as well as animal studies to demonstrate in vivo efficacy. PROPOSED COMMERCIAL APPLICATION: Inhibitors of the bacterial DNA adenine methyltransferase, if shown to be potent antibiotics, hold grant promise in the fight against numerous infectious diseases. The commercialization of these drugs will require several years.

The focus of this proposal is to develop drug candidates that inhibit DNA Adenine Methyltransferase (DAM) as a new class of antibiotics for the treatment of bacterial infection. Widespread antibiotic resistant pathogenic organisms create life-threatening conditions for patients in both hospital and community settings. To deal with increasing drug resistance, new antibacterial agents are desperately needed. We have established purified enzymes and in vitro and in vivo assays for high throughput compound screening, and compound optimization for potency and selectivity. Screening of chemical diversity libraries has identified several new classes of compounds that inhibit bacterial DAM. We will expand the high throughput screening effort initiated in the SBIR Phase I to include assay automation, the screening of additional small molecule template libraries, and the identification and characterization of new lead compounds. Existing lead compounds will be prioritized on the basis of their potential for chemical optimization and mechanism type. Combinatorial and/or focused libraries will be prepared and screened for the most promising template series and structure-activity relationships (SAR) developed. Chemical optimization will be performed with respect to potency, selectivity against mammalian enzymes, in silico and experimental ADME parameters, and uptake by bacterial cells. Potential drug candidates will be evaluated in animal and cell-based model systems for efficacy and toxicity. A wide spectrum of clinically important pathogenic bacteria will be screened for sensitivity to methylation inhibition. The outcome of this 2-year development program will be a drug candidate ready for Phase I clinical evaluation in humans.

Thesaurus Terms:
DNA methylation, antibiotic, bacterial protein, chemical structure function, drug design /synthesis /production, enzyme inhibitor, methyltransferase chemical registry /resource, drug screening /evaluation, methylguanine DNA methyltransferase