title: Serum protein profiling by miniaturized solid-phase extraction and matrix-assisted laser desorption/ionization mass spectrometry.
abstract: Serum profiling by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) holds promise as a clinical tool for early diagnosis of cancer and other human diseases. Sample preparation is key to achieving reproducible and well-resolved signals in MALDI-MS; a prerequisite for translation of MALDI-MS based diagnostic methods to clinical applications. We have investigated a number of MALDI matrices and several miniaturized solid-phase extraction (SPE) methods for serum protein concentration and desalting with the aim of generating reproducible, high-quality protein profiles by MALDI-MS. We developed a simple protocol for serum profiling that combines a matrix mixture of 2,5-dihydroxybenzoic acid and alpha-cyano-4-hydroxycinnamic acid with miniaturized SPE and MALDI-MS. Functionalized membrane discs with hydrophobic, ion-exchange or chelating properties allowed reproducible MALDI mass spectra (m/z 1000-12,000) to be obtained from serum. In a proof-of-principle application, SPE with chelating material and MALDI-MS identified protein peaks in serum that had been previously reported for distinguishing a person diagnosed with breast cancer from a control. These preliminary results indicate that this simple SPE/MALDI-MS method for serum profiling provides a versatile and scalable platform for clinical proteomics.
authors.affiliation: Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark.
authors.forename: Anne K
authors.initials: AK
authors.lastname: Callesen
authors.forename: Shabaz
authors.initials: S
authors.lastname: Mohammed
authors.forename: Jakob
authors.initials: J
authors.lastname: Bunkenborg
authors.forename: Torben A
authors.initials: TA
authors.lastname: Kruse
authors.forename: Søren
authors.initials: S
authors.lastname: Cold
authors.forename: Ole
authors.initials: O
authors.lastname: Mogensen
authors.forename: Rene dePont
authors.initials: Rd
authors.lastname: Christensen
authors.forename: Werner
authors.initials: W
authors.lastname: Vach
authors.forename: Per E
authors.initials: PE
authors.lastname: Jørgensen
authors.forename: Ole N
authors.initials: ON
authors.lastname: Jensen
mesh_terms: D001798:Blood Proteins / Q000032:analysis*; D001943:Breast Neoplasms / Q000097:blood* / Q000175:diagnosis; D005260:Female; D006801:Humans; D044967:Serum / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D001798:Blood Proteins