title: Comparative proteomic analysis of cell lines and scrapings of the human intestinal epithelium.
abstract: BACKGROUND
  In vitro models are indispensable study objects in the fields of cell and molecular biology, with advantages such as accessibility, homogeneity of the cell population, reproducibility, and growth rate. The Caco-2 cell line, originating from a colon carcinoma, is a widely used in vitro model for small intestinal epithelium. Cancer cells have an altered metabolism, making it difficult to infer their representativity for the tissue from which they are derived. This study was designed to compare the protein expression pattern of Caco-2 cells with the patterns of intestinal epithelial cells from human small and large intestine. HT-29 intestinal cells, Hep G2 liver cells and TE 671 muscle cells were included too, the latter two as negative controls.
  
  
  RESULTS
  Two-dimensional gel electrophoresis was performed on each tissue and cell line protein sample. Principal component and cluster analysis revealed that global expression of intestinal epithelial scrapings differed from that of intestinal epithelial cell lines. Since all cultured cell lines clustered together, this finding was ascribed to an adaptation of cells to culture conditions and their tumor origin, and responsible proteins were identified by mass spectrometry. When investigating the profiles of Caco-2 cells and small intestinal cells in detail, a considerable overlap was observed.
  
  
  CONCLUSIONS
  Numerous proteins showed a similar expression in Caco-2 cells, HT-29 cells, and both the intestinal scrapings, of which some appear to be characteristic to human intestinal epithelium in vivo. In addition, several biologically significant proteins are expressed at comparable levels in Caco-2 cells and small intestinal scrapings, indicating the usability of this in vitro model. Caco-2 cells, however, appear to over-express as well as under-express certain proteins, which needs to be considered by scientists using this cell line. Hence, care should be taken to prevent misinterpretation of in vitro obtained findings when translating them to the in vivo situation.
authors.affiliation: Maastricht Proteomics Center, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Department of Human Biology, Maastricht University, Maastricht, The Netherlands. K.Lenaerts@HB.unimaas.nl
authors.forename: Kaatje
authors.initials: K
authors.lastname: Lenaerts
authors.forename: Freek G
authors.initials: FG
authors.lastname: Bouwman
authors.forename: Wouter H
authors.initials: WH
authors.lastname: Lamers
authors.forename: Johan
authors.initials: J
authors.lastname: Renes
authors.forename: Edwin C
authors.initials: EC
authors.lastname: Mariman
mesh_terms: D000230:Adenocarcinoma / Q000737:chemistry / Q000235:genetics / Q000473:pathology; D018938:Caco-2 Cells; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000235:genetics; D045744:Cell Line, Tumor; D020869:Gene Expression Profiling; D019073:HT29 Cells; D006801:Humans; D007413:Intestinal Mucosa / Q000737:chemistry* / Q000378:metabolism / Q000473:pathology*; D007414:Intestinal Neoplasms / Q000737:chemistry / Q000235:genetics / Q000473:pathology; D008527:Medulloblastoma / Q000737:chemistry / Q000235:genetics / Q000473:pathology; D009363:Neoplasm Proteins / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics; D010455:Peptides / Q000032:analysis / Q000235:genetics; D011506:Proteins / Q000032:analysis* / Q000235:genetics; D040901:Proteomics / Q000379:methods
chemical_list: D009363:Neoplasm Proteins; D010455:Peptides; D011506:Proteins