Marine Actinomycetes as a Resource for Anticancer Natural Products

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DESCRIPTION (provided by applicant): Fermentation derived natural products from actinomycetes and other bacteria have been an important component of drug discovery inspiring 50% of clinically approved drugs and proven to be invaluable tools in cancer research. Natural products often exert their effects potently and exhibit high specificity - making them useful to probe signaling pathways related to cancer. As such, a continued effort to identify new natural products with potent biological activity relevant to human cancers is an important endeavor. The goal of this project is to identify new natural products that can be lead structures for the development of novel cancer therapeutics or biochemical probes. A multi-faceted approach that combines microbiology, natural products chemistry and collaboration with experts in cancer biology will be used to accomplish this goal. Specifically, we propose to develop new empirical and biochemical techniques to culture actinomycetes from marine habitats, by taking advantage of environmental factors such as pH, pO2 and chemical signaling. As it is widely believed that only a small percentage of bacteria are culturable, new techniques to isolate secondary metabolite producing bacteria are necessary. The collection of marine bacteria will serve as the foundation to build a natural product fraction library for biological screening efforts. We will use a combination of biochemical target-based assays, cell-based phenotypic assays and selective cytotoxicity studies to identify molecules that interact with signal transduction pathways (eg. apoptosis, necrosis, Wnt/?-catenin, HIF) and modulate epigenetic factors such as DNA methyltransferase and histone deacetylase. An example of a specific biological target, we will utilize a cell-based assay to discover molecules that interact specifically in the Wnt pathway using a Wnt responsive cell line, which is important in large number of cancers (most notably up to 90% of colon cancer). To accommodate the chemical evaluation of active hits in the large number of bioassays proposed, we will develop analytical chemistry techniques based on LC-SPE-NMR technology for rapid quantitative and qualitative analysis. Finally, we will use traditional natural products chemistry techniques to characterize new secondary metabolites that we identify in our biological screening.