| 2559 Profiling of Salivary Peptides in Oral Squamous Cell Carcinoma (OSCC) | ||
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K.J. RITTENBACH, S.J. FISHER, H.E. WITKOWSKA, S.C. HALL, S.J. ROBINSON, S.E. DIXON, R. NILES, B.L. SCHMIDT, and M. HARDT, University of California San Francisco, USA OSCC, the sixth most common cancer, has a low five-year survival rate, necessitating early detection. Diseased states such as OSCC can impact protein and peptide composition in saliva, an emerging diagnostic fluid. To discover and assess cancer biomarkers, proteomic approaches are increasingly employed. Proteomic technologies, which focus on detection and quantification, rarely give information about activity, a key factor in assessing normal and pathological protein functions. Here, we describe a novel mass spectrometry-based approach to evaluate cancer-related proteinase activity by profiling peptides in whole saliva from a patient before and after OSCC tumor resection. Objective: This pilot study explores associations between OSCC and the composition of the low-molecular weight fraction of whole saliva before and after surgical treatment of patients at the UCSF Oral and Maxillofacial Surgery Service. Methods: Whole saliva samples were collected before and after complete tumor resection. Proteinase activity of both samples was assessed by stable isotope labeling of the peptide cleavage products, which were separated by reversed phase liquid chromatography prior to matrix-assisted laser desorption ionization time-of-flight tandem mass spectrometry analysis. Results: This novel methodology allowed detection and sequencing of a complex suite of peptides in whole saliva. These peptide profiles allowed classification of proteinase activities by which they were generated, revealing substantial differences between the two samples. Conclusions: Proteinases associated with OSCC use endogenous proteins and peptides in saliva as substrates, thereby modifying the low-molecular-weight composition of this body fluid. By analyzing whole saliva samples collected before and after complete tumor resection, we identified signature peptides and proteinase activities that potentially correlate with the disease state. These cancer-specific profiles, superimposed on normal salivary proteolysis, may be clinically useful as markers for diagnosis and treatment response. Additionally, the proteinases we characterized could be novel therapeutic targets. Support:PACCTR, NIH-DE016274, Sandler-New-Technologies-Fund | ||
| Seq #267 - Junior Category 10:45 AM-12:00 PM, Saturday, March 24, 2007 Ernest N. Morial Convention Center Exhibit Hall I2-J | ||
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