A Novel, High-Throughput Workflow for Discovery and Identification of Serum Carrier Protein-Bound Peptide Biomarker Candidates in Ovarian Cancer Samples

George Mason University, 페어팩스, Virginia, United States
Clinical Chemistry (Impact Factor: 7.91). 06/2007; 53(6):1067-74. DOI: 10.1373/clinchem.2006.080721
Source: PubMed


Most cases of ovarian cancer are detected at later stages when the 5-year survival is approximately 15%, but 5-year survival approaches 90% when the cancer is detected early (stage I). To use mass spectrometry (MS) of serum proteins for early detection, a seamless workflow is needed that provides an opportunity for rapid profiling along with direct identification of the underpinning ions.
We used carrier protein-bound affinity enrichment of serum samples directly coupled with MALDI orthagonal TOF MS profiling to rapidly search for potential ion signatures that contained discriminatory power. These ions were subsequently directly subjected to tandem MS for sequence identification.
We discovered several biomarker panels that enabled differentiation of stage I ovarian cancer from unaffected (age-matched) patients with no evidence of ovarian cancer, with positive results in >93% of samples from patients with disease-negative results and in 97% of disease-free controls. The carrier protein-based approach identified additional protein fragments, many from low-abundance proteins or proteins not previously seen in serum.
This workflow system using a highly reproducible, high-resolution MALDI-TOF platform enables rapid enrichment and profiling of large numbers of clinical samples for discovery of ion signatures and integration of direct sequencing and identification of the ions without need for additional offline, time-consuming purification strategies.

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Available from: Kevin P Rosenblatt, Feb 18, 2014
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    • "It is important to highlight that higher peptide levels could be due either to an increasing level of circulating precursor protein, or to an increase of protein degradation pathways. In the case of complement C3, there are evidences of increased plasmatic level related in cancer (Liang et al., 2010; Lopez et al., 2007). Moreover, complement cascade is known to be involved in cancer development (Markiewski and Lambris, 2009; Rutkowski et al., 2010) and recently Dowling et al. (Dowling et al., 2012) demonstrated an increased complement activation in RC patients. "
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    • "It should be noted that the objective of our study was not to decipher the proteome of urine OvCa and thus, it is not surprising that more proteins were not overlapping with Fredolini et al. Another study, by Lopez et al., looked at the serum proteome of 110 healthy individuals and 453 patients with OvCa (including stages I-IV) [30]. The authors identified 160 proteins that were overexpressed in ovarian cancer compared to healthy controls. "
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    • "Differential expression of these proteins in sera was also confirmed by western blot and ELISA. Lopez et al. [47] set-up a workflow using carrier protein-bound affinity enrichment of serum samples directly coupled with MALDI/TOF. Subsequent tandem MS analysis defined the serum protein-bound peptides' sequence. "
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