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Both small molecules and antibodies are powerful tools for research in biological mechanisms and therapeutics. The discovery of such molecules involves two opposite starting points: one being specific targets and the other being phenotypic screens. The first part of this thesis focuses on drug development starting with a specific target. The second part of this thesis focuses on identification of ferroptosis biomarkers by phenotypic screen. The specific target highlighted in the first part of this thesis is KRAS (Kirsten rat sarcoma viral oncogene homolog), the most commonly mutated oncogene in human pancreatic cancers, colorectal cancers, and lung cancers. The high prevalence of KRAS mutations and its prominent role in many cancers make it a potentially attractive drug target; however, it has been difficult to design small molecule inhibitors of mutant K-Ras proteins. Here, we identified a putative small molecule binding site on K-RasG12D, which we have termed the P110 site (due to its adjacency to proline 110), using computational analyses of the protein structure. We then confirmed that one compound, named K-Ras Allosteric Ligand KAL-21404358, might bind to the P110 site of K-RasG12D using a combination of computational and biochemical approaches. The phenotypic screen used in the second part of this thesis focus on the process of ferroptosis, a form of regulated cell death process driven by the iron-dependent accumulation of polyunsaturated-fatty-acid-containing phospholipids (PUFA-PLs). Currently, there is no way to selectively stain ferroptotic cells in tissue sections to characterize relevant models and diseases. To circumvent this problem, we immunized mice with membranes from diffuse large B Cell lymphoma (DLBCL) cells treated with piperazine erastin (PE), and screened the generated monoclonal antibodies. The results suggested that for the first time we could detect cells undergoing ferroptosis in human tissue sections. In summary, these two projects illustrate how molecular screening and design starting from either a specific target or a phenotype screen aid in drug and biomarker development. |
