Abstract

Proteases – A Promising and Untapped Group of Protein Biomarkers for a Wide Range of Disease Diagnostics

Michael Heller, Distinguished Scientist - Knight Cancer Institute, Center for Cancer Early Detection and Research (CEDAR), Oregon Health & Science University (OHSU)

Proteases represent a large class of enzymes that degrade proteins and have been associated with a wide range of diseases. These include: cardiovascular diseases; coagulation disorders; inflammatory diseases, diabetes, sepsis; infectious diseases and cancer. While proteases have seen some limited use in disease diagnostics, their full potential has not been exploited. Also, in most cases there detection is carried out using classical immunofluorescent antibody-protein binding reactions. Because they are catalyst which rapidly convert specific substrates into products, they offer an added advantage for signal amplification. At our UCSD lab we have capitalized on this property and developed rapid sample to answer protease assays based on fluorescent charge-changing peptide substrates. These assays can be carried our using very small volumes (5ul-10ul) of whole blood samples. No sample preparation is required and the fluorescent peptide products can be detected in about 30 minutes using simple mini-gel electrophoretic formats. By way of just one example we have shown elevated digestive proteolytic activity in the peripheral blood of individuals with Type-2 Diabetes. More recently we have preliminary results indicating the elevation of specific proteases in various cancers. The ultimate goal is to use our rapid charge-changing fluorescent peptide technology to fully exploit the promise of protease biomarkers for disease diagnostics, including cancer.