SBIR-STTR Award

By simply growing Bacillus anthracis in the presence of sub-inhibitory concentrations of antibiotics it has been made resistant to all commonly used drugs such as penicillin, doxycycline and Ciprofloxacin. If one of these antibiotic resistant strains were used in a future terrorist attack there will be limited or no therapeutic treatments available. Thus there is an urgent need to develop new classes of antibiotics to treat resistant B. anthracis. A shotgun antisense technology is proposed for the rapid identification of B. anthracis essential genes, whose protein products can serve as targets for new classes of antibiotics. This technology conditionally and incrementally reduces the level of an essential gene product, which provides a means to hypersensitize cells to compounds that inhibit that target and thus provides a cell-based assay for drug discovery. Phase I of this proposal will be to develop the molecular biology tools for conditionally delivering random genomic antisense RNA fragments to B. anthracis cells. In Phase II a genome-wide screen in B. anthracis will identify a comprehensive list of essential genes. We have developed a unique microbial relational database, which allows the prioritization of targets based on conservation among bacterial pathogens having no or limited homology to human proteins. Bioinformatics analyses undertaken prior to drug screening should help ensure that new antimicrobial drugs have maximal impact upon the disease and minimal impact on the patient. Cell-based assays will be optimized for these prioritized targets and entered into an established high throughput chemical screening program against the company's chemical library of over 250,000 compounds. This Gene-to-Screen technology platform has been developed to allow miniaturized drug screens to be developed for any validated target within 2-3 weeks. Promising hit compounds would then be rapidly developed and advanced into lead-optimization chemistry. New classes of antibiotics would help deter and treat against future bioterrorist attacks and could also be used to treat common drug resistant pathogens.

Thesaurus Terms:
Bacillus anthracis, antibiotic, antisense nucleic acid, bacterial genetics, drug discovery /isolation, genetic promoter element biochemical evolution, informatics, molecular biology information system, transfection /expression vector chemical registry /resource, clinical research, high throughput technology

New therapeutics are urgently needed to treat infections caused by drug-resistant variants of bacterial pathogens, particularly pathogens likely to be utilized as weapons of terrorism or biological warfare. The objective of the proposed work is to discover and develop new therapeutics for treatment of infections caused by Bacillus anthracis, which remains the most readily weaponized, easily dispersed and among the deadliest of biological materials that might be employed for purposes of terrorism or biological warfare. B. anthracis bacteria are also easy to obtain from natural sources and are easy to manipulate genetically, even with rudimentary facilities and limited microbiological expertise, making this pathogen the agent of choice for terrorist organizations. Under Phase I funding, we demonstrated that an antisense (AS) RNA expression technology developed at Elitra Pharmaceuticals to identify essential genes is readily adapted for use in B. anthracis. This creates the opportunity to exploit Elitra's highly sensitive, AS-based, whole-cell screening assays to discover drug leads for the development of new B. anthracis therapeutics. As projected in the original Phase I application, the Phase II research program will build directly on the success of the Phase I proof-of-concept studies. We propose to implement the AS-based essential gene discovery survey on a large scale in order to identify both narrow-spectrum and broad-spectrum drug targets. More importantly, we will use AS-sensitized B. anthracis strains to conduct whole-cell screens for discovery of drug leads. Elitra will commit matching funds from other sources to pursue lead-optimization chemistry and pre-clinical development of attractive lead series, driving aggressively to the goal of producing new products of high public health value and strategic importance.

Thesaurus Terms:
Bacillus anthracis, anthrax, antibiotic, antisense nucleic acid, drug design /synthesis /production, drug discovery /isolation, gene expression bacterial genetics, drug screening /evaluation, genetic strain, high throughput technology, nonhuman therapy evaluation, nucleic acid sequence, operon, small molecule bioinformatics, bioterrorism /chemical warfare, genetic library, laboratory mouse, polymerase chain reaction