Performance Diversity of Reduced Flavones and Autophagy Modulators in Cancer and Retinal Diseases

My graduate work consists of two parts with the first part focused on testing biological performance diversity of an sp3-enriched flavonoid library. The natural product-inspired library was synthesized to determine chemical features important for diverse biological performance. The reduced flavone library was synthesized in 3-4 steps form the γ-pyrones in 19-67% yield, and incorporated diverse chemical properties (e.g. fsp3 and lipophilicity) and features (appendages and stereochemistry). Three compound classes from the library (pyrones, alcohols, and esters) and known flavonoids were tested in a cytotoxicity assay and Cell Painting. The pyrone class had the most biological performance diversity compared to the other classes in both the cytotoxicity assay and Cell Painting due to appendage diversity. Though the Cell Painting showed low biological activity for the ester class, the cytotoxicity assay revealed that both appendages and stereochemistry are important for performance diversity. Key trends that correlated with improved biological performance diversity in this library were lipophilicity and scaffold, demonstrating that an increase in fsp3 does not necessarily lead to more diverse biological activities in every scaffold. The second part of my graduate work consisted of screening compounds in phenotypic assays to discover compounds with novel mechanisms of action (MOA). A high-content phenotypic screen of 10,000 compounds was conducted in eGFP-LC3 HeLa cells to identify both autophagy inhibitors and activators. After structure-activity relationship (SAR) analysis, two autophagy inhibitors and two autophagy activators were selected for further testing. Analogues were synthesized with improved potency based on their IC50 or EC50 values. In the inhibition project, cancer cell line profiling revealed cell lines that were sensitive and resistant to our autophagy inhibitors. Our autophagy activators were tested in a dual reporter assay that distinguishes between late-stage autophagy inhibitors and autophagy activators. These two hits were further confirmed to be true autophagy activators in an autophagic flux western blot with Bafilomycin A1 co-treatment and Lysotracker and DQ-BSA assays. The mTOR-independent MOA made these hits attractive for testing in an in vitro retinal ischemia model, and the two hits attenuated neuronal cell death.