title: Proteome analysis of metastatic colorectal cancer cells recognized by the lectin Helix pomatia agglutinin (HPA).
abstract: The lectin from Helix pomatia (HPA) binds to adenocarcinomas with a metastatic phenotype but the glycoconjugates of cancer cells that bind to the lectin have yet to be characterized in detail. We used a model of metastatic (HT29) and nonmetastatic (SW480) human colorectal cancer cells and a proteomic approach to identify HPA binding glycoproteins. Cell membrane proteins purified by HPA affinity chromatography, were separated by 2-DE and analyzed by MS. Competitive inhibition experiments with N-acetylgalactosamine, N-acetylglucosamine, and sialic acid confirmed that HPA binding was via a glycan-mediated interaction. Western blot analysis showed that HPA binds to proteins not recognized by an antibody against blood group A epitope. The proteomic study showed the main HPA binding partners include integrin alphav/alpha6 and annexin A2/A4. These proteins were found complexed with microfilament proteins alpha and beta tubulin, actin, and cytokeratins 8 and 18. HPA also bound to Hsp70, Hsp90, TRAP-1, and tumor rejection factor 1. This study revealed that the prognostic utility of HPA lies in its ability to bind simultaneously to many glycoproteins involved in cell migration and signaling, in addition, the proteins recognized by HPA are glycosylated with structures distinct from the blood group A epitope.
authors.affiliation: School of Biosciences, University of Westminster, London, UK.
authors.forename: Julien
authors.initials: J
authors.lastname: Saint-Guirons
authors.forename: Elton
authors.initials: E
authors.lastname: Zeqiraj
authors.forename: Udo
authors.initials: U
authors.lastname: Schumacher
authors.forename: Pamela
authors.initials: P
authors.lastname: Greenwell
authors.forename: Miriam
authors.initials: M
authors.lastname: Dwek
mesh_terms: D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000556:secondary*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D037102:Lectins / Q000032:analysis* / Q000187:drug effects / Q000276:immunology; D008565:Membrane Proteins / Q000276:immunology; D018613:Microscopy, Confocal; D017350:N-Acetylgalactosaminyltransferases / Q000494:pharmacology; D017351:N-Acetylglucosaminyltransferases / Q000494:pharmacology; D019158:N-Acetylneuraminic Acid / Q000494:pharmacology; D011379:Prognosis; D011485:Protein Binding; D040901:Proteomics; D012680:Sensitivity and Specificity; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured
chemical_list: C038095:Helix lectin; D037102:Lectins; D008565:Membrane Proteins; D017350:N-Acetylgalactosaminyltransferases; D017351:N-Acetylglucosaminyltransferases; D019158:N-Acetylneuraminic Acid