Use of cancer-specific yeast-secreted in vivo biotinylated recombinant antibodies for serum biomarker discovery
Strategies to discover circulating protein markers of ovarian cancer are urgently needed. We developed a novel technology that permits us to isolate recombinant antibodies directed against the potential serum biomarkers, to facilitate the further development of affinity reagents necessary to construct diagnostic tests.
Methods: This study presents a novel discovery approach based on serum immunoprecipitation with cancer-specific in vivo biotinylated recombinant antibodies (biobodies) derived from differentially selected yeast-display scFv, and analysis of the eluted serum proteins by electrophoresis and/or mass spectrometry.
Results: Using this strategy we identified catabolic fragments of complement factors, EMILIN2, Von Willebrand factor and phosphatidylethanolamine-binding protein 1 (PEBP1 or RKIP) in patient sera.
To our knowledge, this is the first report of a soluble form of PEBP1 in human. Independent evidence for ovarian cancerspecific expression of PEBP1 in patient sera was found by ELISA assays and antibody arrays with anti-PEBP1 antibodies.
PEBP1 was detected in 29 out of 30 ascites samples and discriminated ovarian cancer sera from controls (p=0.02). Finally, we confirmed by western blots the presence of a 21- 23 kDa fragments corresponding to the expected size of PEBP1 but we also showed additional bands of 38 kDa and 50-52 kDa in various tissues and cell lines.
Conclusion: We conclude that the novel strategy described here allows the identification of candidate biomarkers that can be variants of normally expressed proteins or that display cancers-specific post-translational modifications.
Author: Nathalie Scholler, Jennifer A Gross, Barbara Garvik, Lance Wells, Yan Liu, Christian M Loch, Arturo B Ramirez, Martin M McIntosh, Paul D Lampe and Nicole Urban
Credits/Source: Journal of Translational Medicine 2008, 6:41
Published on: 2008-07-24
Copyright by the authors listed above - made available via BioMedCentral (Open Access). Please
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