title: The high affinity selectin glycan ligand C2-O-sLex and mRNA transcripts of the core 2 beta-1,6-N-acetylglucosaminyltransferase (C2GnT1) gene are highly expressed in human colorectal adenocarcinomas.
abstract: BACKGROUND
  The metastasis of cancer cells and leukocyte extravasation into inflamed tissues share common features. Specialized carbohydrates modified with sialyl Lewis x (sLex) antigens on leukocyte membranes are ligands for selectin adhesion molecules on activated vascular endothelial cells at inflammatory sites. The activity of the enzyme core 2 beta1,6 N-acetylglucosaminyltransferase (C2GnT1) in leukocytes greatly increases their ability to bind to endothelial selectins. C2GnT1 is essential for the synthesis of core 2-branched O-linked carbohydrates terminated with sLex (C2-O-sLex). Our goal was to determine the expression profiles of C2-O-sLex in the malignant progression and metastasis of colorectal adenocarcinomas. The well characterized CHO-131 monoclonal antibody (mAb) specifically recognizes C2-O-sLex present in human leukocytes and carcinoma cells. Using CHO-131 mAb, we investigated whether C2-O-sLex was present in 113 human primary colorectal adenocarcinomas, 10 colorectal adenomas, 46 metastatic liver tumors, 28 normal colorectal tissues, and 5 normal liver tissues by immunohistochemistry. We also examined mRNA levels of the enzyme core 2 beta1,6-N-acetylglucosaminyltransferase (C2GnT1) in 20 well, 15 moderately, and 2 poorly differentiated colorectal adenocarcinomas, and in 5 normal colorectal tissues by using quantitative real-time polymerase chain reactions (RT-PCR).
  
  
  RESULTS
  We observed high reactivity with CHO-131 mAb in approximately 70% of colorectal carcinomas and 87% of metastatic liver tumors but a lack of reactivity in colorectal adenomas and normal colonic and liver tissues. Positive reactivity with CHO-131 mAb was very prominent in neoplastic colorectal glands of well to moderately differentiated adenocarcinomas. The most intense staining with CHO-131 mAb was observed at the advancing edge of tumors with the deepest invasive components.Finally, we analyzed C2GnT1 mRNA levels in 37 colorectal adenocarcinomas and 5 normal colorectal tissues by RT-PCR. Significantly, we observed a greater than 15-fold increase in C2GnT1 mRNA levels in colorectal adenocarcinomas compared to normal colorectal tissues.
  
  
  CONCLUSIONS
  C2-O-sLex, detected by the CHO-131 mAb, is a tumor associated antigen whose expression is highly upregulated in colorectal adenocarcinomas and metastatic liver tumors compared to normal tissues. C2-O-sLex is a potentially useful early predictor of metastasis.
authors.affiliation: Department of Veterinary Clinical Sciences, University of Minnesota, Room C339, Veterinary Medical Center, 1352 Boyd Avenue, St, Paul, MN 55108, USA. sthil001@umn.edu
authors.forename: Catherine A
authors.initials: CA
authors.lastname: St Hill
authors.forename: Mariya
authors.initials: M
authors.lastname: Farooqui
authors.forename: Gregory
authors.initials: G
authors.lastname: Mitcheltree
authors.forename: H Evin
authors.initials: HE
authors.lastname: Gulbahce
authors.forename: Jose
authors.initials: J
authors.lastname: Jessurun
authors.forename: Qing
authors.initials: Q
authors.lastname: Cao
authors.forename: Bruce
authors.initials: B
authors.lastname: Walcheck
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D000951:Antigens, Neoplasm / Q000235:genetics / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D050260:Carbohydrate Metabolism; D003106:Colon / Q000166:cytology / Q000378:metabolism; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D019040:E-Selectin / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008099:Liver / Q000166:cytology / Q000378:metabolism; D008113:Liver Neoplasms / Q000175:diagnosis / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D017351:N-Acetylglucosaminyltransferases / Q000235:genetics / Q000378:metabolism*; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D011134:Polysaccharides / Q000378:metabolism; D011379:Prognosis; D011485:Protein Binding; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D019040:E-Selectin; D011134:Polysaccharides; D012333:RNA, Messenger; D017351:N-Acetylglucosaminyltransferases; C053024:beta-1,3-galactosyl-O-glycosyl-glycoprotein beta-1,6-acetylglucosaminyl transferase