In phase I we have identified a new class of active-site directed inhibitors of DMA polymerase HIE, a novel replicative enzyme in Gram+ bacteria. The compounds, 7-substituted-N2-(3,4-dichlorobenzyl)guanines """"""""DCBGs"""""""", are potent enzyme inhibitors, and selected derivatives have potent and broad activity against clinically relevant Gram+ bacteria. We have identified the first active site directed inhibitors of the related DNA polymerase HIE from Gram- bacteria, i.e. E. coli. In addition, we have established a collaboration to crystallize and solve the structure of a complex between E. fecalis pol IIIE, DNA and one of our inhibitors. ? Based on the results of phase I, we will pursue designation of a lead antibiotic compound by in vivo testing in systemic and toplical bacterial infection models. We will use both QSAR analysis and structure-based drug design to discover new platform inhibitors of the pol HIE target. The following specific aims will be pursued: ? 1. scale-up synthesis of lead compound candidates and formulations for evaluation in animal models of bacterial infection; synthesis of 7-substituted analogs with enhanced pol HIE inhibitory and antibacterial activity in vitro. ? 2. solve the structure of E. fecalis pol IIIE:DNA:inhibitor complexes, and use the coordinates for understanding the basis of inhibition of the enzyme and for further rational, computer-based drug design (collaboration with Dr. Mark Jedrzejas, Children's Hospital of Oakland Research Institute). ? 3. continue assays of compounds for enzyme inhibition (pol IIIC, pol HIE), antibacterial activity, selectivity, cytotoxicity; incidence of resistance and mechanism(s) of resistance, by cloning and sequencing of targets (by subcontract to Microbiotix Inc.); test candidate drugs against clinical isolates of Gram+ and Gram- bacteria, bactericidal assays, combination studies with marketed antibiotics (by subcontract to UMass Medical School). ? 4. develop analytical methods for analysis of candidates in animal plasma, drug uptake and distribution by various routes in mice, acute toxicity, in vitro metabolism and stability studies. ? 5. evaluate candidate drugs for activity in animal models of Gram+ and Gram- infections (if warranted), emphasizing systemic antibiotic-resistant S. aureus, E. fecalis and S. pneumoniae in mice and topical S. aureus infections in guinea pigs.. ? Potent inhibition of Gram+ pol HIE and pol IIIC may lead to antibiotics with reduced incidence of resistance. ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Small Business Innovation Research Grants (SBIR) - Phase II (R44)
Project #
2R44AI051103-02A1
Application #
6883132
Study Section
Special Emphasis Panel (ZRG1-SSS-L (10))
Program Officer
Peters, Kent
Project Start
2001-11-01
Project End
2007-03-31
Budget Start
2005-04-01
Budget End
2006-03-31
Support Year
2
Fiscal Year
2005
Total Cost
$944,079
Indirect Cost
Name
Glsynthesis, Inc.
Department
Type
DUNS #
003231854
City
Worcester
State
MA
Country
United States
Zip Code
01605
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Xu, Wei-Chu; Wright, George E; Brown, Neal C et al. (2011) 7-Alkyl-N(2)-substituted-3-deazaguanines. Synthesis, DNA polymerase III inhibition and antibacterial activity. Bioorg Med Chem Lett 21:4197-202
Torti, Andrea; Lossani, Andrea; Savi, Lida et al. (2011) Clostridium difficile DNA polymerase IIIC: basis for activity of antibacterial compounds. Curr Enzym Inhib 7:147-153