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- Mörtstedt, Harriet, et al.
(författare)
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Strategy for identification and detection of multiple oxidative modifications within proteins applied on persulfate-oxidized hemoglobin and human serum albumin.
- 2011
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Ingår i: Rapid Communications in Mass Spectrometry. - : Wiley. - 1097-0231 .- 0951-4198. ; 25:2, s. 327-340
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Tidskriftsartikel (refereegranskat)abstract
- Oxidative stress has been suggested as an underlying mechanism of many human diseases. However, definitive evidence for this association has not been presented due to different shortcomings of the methods used to measure biomarkers of oxidative stress. Persulfates are oxidizing agents known to elicit hypersensitive reactions from the airways and skin. Despite a frequent use of persulfates at many work places, no biomarkers for persulfate exposure are available. The aim of this study was to develop a strategy for the identification and detection of multiple oxidative modifications within proteins. This strategy was applied on persulfate-oxidized proteins to identify oxidized peptides suitable for further investigation as biomarkers of persulfate exposure or oxidative stress. A strategy for the identification and the relative quantification of multiple oxidative modifications within proteins was developed. The usage of two software packages facilitated the search for modified peptides to a great extent. Oxidized peptides were relatively quantified using liquid chromatography/tandem mass spectrometry in selected reaction monitoring mode. The result showed that persulfates oxidize tryptophans and methionines resulting in mass shifts of 16 and/or 32 Da. Also, oxidized albumin peptides in nasal lavage fluid samples from subjects challenged with persulfate were detected. The oxidation degree before and after challenge remained constant for peptides containing methionine sulfoxide. For peptides containing oxidized tryptophan the oxidation degree increased after exposure. Some of these oxidized peptides may be suitable as biomarkers; however, further evaluation is required.
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- Opstal-van Winden, Annemieke W. J., et al.
(författare)
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Searching for early breast cancer biomarkers by serum protein profiling of pre-diagnostic serum; a nested case-control study
- 2011
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Ingår i: BMC Cancer. - : Springer Science and Business Media LLC. - 1471-2407. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Background: Serum protein profiles have been investigated frequently to discover early biomarkers for breast cancer. So far, these studies used biological samples collected at or after diagnosis. This may limit these studies' value in the search for cancer biomarkers because of the often advanced tumor stage, and consequently risk of reverse causality. We present for the first time pre-diagnostic serum protein profiles in relation to breast cancer, using the Prospect-EPIC (European Prospective Investigation into Cancer and nutrition) cohort. Methods: In a nested case-control design we compared 68 women diagnosed with breast cancer within three years after enrollment, with 68 matched controls for differences in serum protein profiles. All samples were analyzed with SELDI-TOF MS (surface enhanced laser desorption/ionization time-of-flight mass spectrometry). In a subset of 20 case-control pairs, the serum proteome was identified and relatively quantified using isobaric Tags for Relative and Absolute Quantification (iTRAQ) and online two-dimensional nano-liquid chromatography coupled with tandem MS (2D-nanoLC-MS/MS). Results: Two SELDI-TOF MS peaks with m/z 3323 and 8939, which probably represent doubly charged apolipoprotein C-I and C3a des-arginine anaphylatoxin (C3a(desArg)), were higher in pre-diagnostic breast cancer serum (p = 0.02 and p = 0.06, respectively). With 2D-nanoLC-MS/MS, afamin, apolipoprotein E and isoform 1 of inter-alpha trypsin inhibitor heavy chain H4 (ITIH4) were found to be higher in pre-diagnostic breast cancer (p < 0.05), while alpha-2-macroglobulin and ceruloplasmin were lower (p < 0.05). C3a(desArg) and ITIH4 have previously been related to the presence of symptomatic and/or mammographically detectable breast cancer. Conclusions: We show that serum protein profiles are already altered up to three years before breast cancer detection.
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