Molecular Diversity and Screening

Natural products chemistry has been an important area of research that fortifies much of the discovery of modern pharmaceuticals approximately half of the current drugs are natural products or derivatives thereof, demonstrating the potential of natural resources for drug discovery. One reason for the suitability of natural products as therapeutics or at least as lead compounds for drug discovery is their biologically relevant chemical diversity. Natural products have evolved with and against their biological targets, which is oftentimes manifested in high-affinity interactions with their receptors. In addition to being a historically prolific source of drugs, Nature has also provided us with arguably the best tool compounds for chemical biology. The Center has unique expertise in natural products chemistry, including the isolation, characterization and biological evaluation of small molecules from terrestrial plants, microorganisms particularly of marine origin and marine sponges and algae to identify and characterize compounds from natural sources that promise new advances in pharmacology. The core provides a state-of-the-art infrastructure to facilitate the discovery of new drug leads addressing multiple aspects of drug discovery ranging from assay development, fractionation, isolation, de-replication strategies and screening campaigns.

The CNPD3 manages a growing collection of purified natural products, natural products fractions, and natural products-derived and synthetic compound libraries, including those arising from Complexity-to-Diversity (CtD) approaches, which provided by UF medicinal chemists that are members of the CNPD3. These libraries are made available for screening with collaborating faculty across UF.

The Center has the capability to run medium- to high- throughput screens (96- and 384-well) and experienced personnel to miniaturize assays. Assay platforms include biochemical assays using colorimetric, fluorescence and ultra-sensitive luminescence outputs including assays designed to quantify protein concentration and protein-protein interactions using the AlphaLISA technology. More recently we have developed high-content screening assays for tissue, cell and organelle morphology and protein expression and localization in 2D and 3D cultured cells and isolated primary cells using the Operetta high- throughput fluorescent confocal microscope with up to four different fluorescent stains. Additionally, sophisticated image analysis procedures are established to quantify tissue, cell and organelle morphology and protein expression and localization and high throughput processing procedures to prepare images for custom analysis by collaborators.

In addition to our chemical libraries, we have acquired libraries of small interfering RNAs (siRNAs) that specifically target the druggable human genome (8,000 targets). The library is arrayed in 96-well format and is spotted out into 384-well screening sets using our in-house robotics. Analogous overexpression screens can be run with arrayed cDNA libraries which are commercially available. These screens can be used not only to discover new targets, but also to interrogate mechanisms of action of drug candidates, since target depletion or overexpression modulates cellular susceptibility to the bioactive compounds. We run similar chemogenomic screen in yeast to identify mechanisms of drug action. Genomic as well as small molecule/natural products library screens also can be extended to screens with isogenic pair cell lines. Comparative screening of certain knockout cells and parental cells for siRNAs and small molecules that specifically affect the target pathway could yield new drug targets and new therapeutic agents, respectively. The CNPD3 also integrates whole-organism screening into its assay platform. In particular, the transparent free living nematode Caenorhabditis elegans is genetically tractable, and mutants and transgenic reporter strains are available for screening. Activity in this in vivo model is predictive of bioavailability. Infrastructure is being developed to accommodate various screening readouts, including luminescence, fluorescence and high-content imaging. Our multidimensional genomic assay platform is complemented by a powerful, focused chemical platform with emphasis on natural products and natural products-like libraries.

CNPD3 Drug Discovery and Screening Platform


Core Leader