e22137 Background: Lung cancer is the most common cause of cancer-related deaths in the world. There is a critical need for new strategies of early lung cancer detection. The identification of tumor-associated antigens and corresponding antibodies is one approach to discovery of diagnostic biomarkers. We used a large phage-displayed recombinant antibody library and normal human lung epithelial and non-small cell lung cancer cell lines to select for and identify recombinant antibodies specific for proteins expressed, or over-expressed, in lung cancer. Methods: The antibody library was used to select for recombinant scFv antibodies reactive with proteins present, or aberrantly expressed, in non-small cell lung cancer cell lines (A549, H549, H157, H23) in comparison to normal lung cell lines (BEAS-2B, 16-HBE, KT). Soluble scFv antibodies were obtained through 2 rounds of phage antibody cross-absorption (on normal cell lines) and selection (on non-small lung cancer cell lines). Soluble scFv were assayed by a high-throughput fluorometric microvolume assay technology (FMAT) against normal and cancer lung cell line proteins. ScFv antibodies selected by FMAT were evaluated further with Western blot-based assays. Results: More than 100 scFv antibodies identified by FMAT bound preferentially to proteins in lung cancer. Of these, 46 scFv were assayed by a high throughput Western slot blot immunoassay against pooled normal lung and lung cancer cell lysates. Eight scFv were assayed in Western blot against individual lung normal and non-small lung cancer cell line lysates. Four of these demonstrated differential binding to normal and cancer cell lysates. Conclusions: In summary, we were able to detect cancer-associated antigens in lung cancer cell lines using a phage display antibody library. In combination with high-throughput fluorescent and Western blot assays, four unique scFv antibodies were selected that differentially bound to normal and lung cancer cell lysates. These scFv will be tested as candidate biomarkers of lung cancer in independent tissue and serum samples from patient with and without lung cancer to determine utility for use in lung cancer diagnosis. No significant financial relationships to disclose.
Development of two novel high-throughput assays to quantify ubiquitylated proteins in cell lysates: application to screening of new anti-malarials