title: Proteomic comparison of colorectal tumours and non-neoplastic mucosa from paired patient samples using iTRAQ mass spectrometry.
abstract: Quantitative mass spectrometry using iTRAQ was used to identify differentially expressed proteins from 16 colorectal cancer (CRC) tumours compared to patient-paired adjacent normal mucosa. Over 1400 proteins were identified and quantitated, with 118 determined as differentially expressed by >1.3-fold, with false discovery rate < 0.05. Gene Ontology analysis indicated that proteins with increased expression levels in CRC tumours include those associated with glycolysis, calcium binding, and protease inhibition. Proteins with reduced levels in CRC tumours were associated with loss of ATP production through: (i) reduced β-oxidation of fatty acids, (ii) reduced NADH production by the tricarboxylic acid cycle and (iii) decreased oxidative phosphorylation activity. Additionally, biosyntheses of glycosaminoglycans and proteoglycans were significantly reduced in tumour samples. Validation experiments using immunoblotting and immunohistochemistry (IHC) showed strong concordance with iTRAQ data suggesting that this workflow is suitable for identifying biomarker candidates. We discuss the uses and challenges of this approach to generate biomarker leads for patient prognostication.
authors.affiliation: Cancer Pharmacology Unit, ANZAC Research Institute and Discipline of Medicine, The University of Sydney, Sydney, Australia.
authors.forename: Lucy
authors.initials: L
authors.lastname: Jankova
authors.forename: Charles
authors.initials: C
authors.lastname: Chan
authors.forename: Caroline L S
authors.initials: CL
authors.lastname: Fung
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Song
authors.forename: Sun Y
authors.initials: SY
authors.lastname: Kwun
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Cowley
authors.forename: Warren
authors.initials: W
authors.lastname: Kaplan
authors.forename: Owen F
authors.initials: OF
authors.lastname: Dent
authors.forename: Elie L
authors.initials: EL
authors.lastname: Bokey
authors.forename: Pierre H
authors.initials: PH
authors.lastname: Chapuis
authors.forename: Mark S
authors.initials: MS
authors.lastname: Baker
authors.forename: Graham R
authors.initials: GR
authors.lastname: Robertson
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Clarke
authors.forename: Mark P
authors.initials: MP
authors.lastname: Molloy
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D015179:Colorectal Neoplasms / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D008297:Male; D013058:Mass Spectrometry / Q000379:methods*; D008875:Middle Aged; D040901:Proteomics
chemical_list: D014408:Biomarkers, Tumor