Abstract 3999: Human Proteome Arrays for Auto-Antibody Identification in Clinical Cancer Studies

Abstract Early detection, identification and classification of cancers still present considerable challenges. Innovations in several areas of research have provided novel and powerful approaches with which to tackle these challenges. Autoantibodies to tumor antigens have been found in cancer patients. Such autoantibodies are potentially ideal diagnostic biomarkers, as they are present in serum, are stable, and can be measured using established serological techniques. In order to discover new autoantibody responses in cancer patients, we have developed an approach based on the generation of protein arrays for systematic identification of auto-reactive antibodies. Our approach makes use of several key technologies: sequence-curated clone libraries, in-vitro protein expression, and a sensitive detection technology based on a proprietary combination of electrochemiluminescence detection and patterned arrays (Multi-Array® Technology, Meso Scale Diagnostics). Using this combination of technologies we plan to generate immobilized arrays of >1,000 proteins, with a high density of proteins per well in a 96-well microtiter plate format. The array of human proteins is selected from our collection of 60,000 mammalian clones (characterized by sequencing). The protein arrays will be used to screen cancer patient sera and controls. During the initial development of this platform we optimized the protocols for in-vitro protein expression and labeling, specifically for immobilization on our Multi-Array plates. With this approach we have demonstrated detection of antigen-specific antibodies down to a concentration of 0.1 ng/mL. We have also validated this approach in a model system, with the detection of auto-reactive antibodies in the sera from 29 patients with a range of auto-immune diseases (Sjogren's syndrome, mixed connective tissue disease, scleroderma, systemic lupus erythematosus, and primary bilary cirrhosis), using 9 cloned autoimmune antigens. In parallel, we also optimized approaches for spotting in-vitro expressed proteins in high density spot/well arrays. In these studies we evaluated a selection of electrode surfaces and protein coupling methods, in combination with various spotting methods, and demonstrated serological measurements in a high density spot/well array. This effort was supported with funding from the NCI #1R44CA130391-1A1. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3999.