(157ah) Engineered Heterobivalent Protein Ligands Enable Early Detection of Disease

Early detection of aggressive diseases leads to better patient outcomes. Currently, a major limitation for the early diagnosis of pancreatic cancer is the inability to detect exceedingly low concentrations of reliable biomarkers associated with initial onset of the disease. In early stages of the disease, physiologically relevant concentrations of circulating cancer markers may be in the femtomolar range, which are currently significantly below any reliable limit of detection. Consequently, establishing a non-invasive method for detecting subtle changes in biomarker levels with high specificity would have a profound impact on the medical community’s ability to successfully treat and cure pancreatic cancer patients. To address this, we develop a heterobivalent ligand based biosensor platform. Using a combination of computational modeling and high-throughput directed evolution, our tandem protein binders can be engineered to non-competitively interact with distinct epitopes of the biomarker of interest. These binding proteins coat the surface of a signal transduction interface which then can act as a molecular actuator that closes upon binding of its target. This conformational gating mechanism then initiates a chemical reaction to trigger signal amplification. In this way, the engineered protein domains form a molecular mechanism which converts the binding of a desired biomarker into a propagating signal. This biosensor platform provides an efficient method for quantifying biomarker levels in patients. Moreover, the ease of use makes it possible to monitor trends in biomarker levels across multiple time points which is expected to be a much more reliable approach at early stages of the disease compared to current methods.