TY - JOUR
T1 - Mass spectrometry-based identification of the tumor antigen UN1 as the transmembrane CD43 sialoglycoprotein
AU - De Laurentiis, Annamaria
AU - Gaspari, Marco
AU - Palmieri, Camillo
AU - Falcone, Cristina
AU - Iaccino, Enrico
AU - Fiume, Giuseppe
AU - Massa, Ornella
AU - Masullo, Mariorosario
AU - Tuccillo, Franca Maria
AU - Roveda, Laura
AU - Prati, Ubaldo
AU - Fierro, Olga
AU - Cozzolino, Immacolata
AU - Troncone, Giancarlo
AU - Tassone, Pierfrancesco
AU - Scala, Giuseppe
AU - Quinto, Ileana
PY - 2011/5
Y1 - 2011/5
N2 - The UN1 monoclonal antibody recognized the UN1 antigen as a heavily sialylated and O-glycosylated protein with the apparent molecular weight of 100-120 kDa; this antigen was peculiarly expressed in fetal tissues and several cancer tissues, including leukemic T cells, breast, and colon carcinomas. However, the lack of primary structure information has limited further investigation on the role of the UN1 antigen in neoplastic transformation. In this study, we have identified the UN1 antigen as CD43, a transmembrane sialoglycoprotein involved in cell adhesion, differentiation, and apoptosis. Indeed, mass spectrometry detected two tryptic peptides of the membrane-purified UN1 antigen that matched the amino acidic sequence of the CD43 intracellular domain. Immunological cross-reactivity, migration pattern in mono- and bi-dimensional electrophoresis, and CD43 gene-dependent expression proved the CD43 identity of the UN1 antigen. Moreover, the monosaccharide GalNAc-O-linked to the CD43 peptide core was identified as an essential component of the UN1 epitope by glycosidase digestion of specific glycan branches. UN1-type CD43 glycoforms were detected in colon, sigmoid colon, and breast carcinomas, whereas undetected in normal tissues from the same patients, confirming the cancer-association of the UN1 epitope. Our results highlight UN1 monoclonal antibody as a suitable tool for cancer immunophenotyping and analysis of CD43 glycosylation in tumorigenesis.
AB - The UN1 monoclonal antibody recognized the UN1 antigen as a heavily sialylated and O-glycosylated protein with the apparent molecular weight of 100-120 kDa; this antigen was peculiarly expressed in fetal tissues and several cancer tissues, including leukemic T cells, breast, and colon carcinomas. However, the lack of primary structure information has limited further investigation on the role of the UN1 antigen in neoplastic transformation. In this study, we have identified the UN1 antigen as CD43, a transmembrane sialoglycoprotein involved in cell adhesion, differentiation, and apoptosis. Indeed, mass spectrometry detected two tryptic peptides of the membrane-purified UN1 antigen that matched the amino acidic sequence of the CD43 intracellular domain. Immunological cross-reactivity, migration pattern in mono- and bi-dimensional electrophoresis, and CD43 gene-dependent expression proved the CD43 identity of the UN1 antigen. Moreover, the monosaccharide GalNAc-O-linked to the CD43 peptide core was identified as an essential component of the UN1 epitope by glycosidase digestion of specific glycan branches. UN1-type CD43 glycoforms were detected in colon, sigmoid colon, and breast carcinomas, whereas undetected in normal tissues from the same patients, confirming the cancer-association of the UN1 epitope. Our results highlight UN1 monoclonal antibody as a suitable tool for cancer immunophenotyping and analysis of CD43 glycosylation in tumorigenesis.
UR - http://www.scopus.com/inward/record.url?scp=79955750270&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79955750270&partnerID=8YFLogxK
U2 - 10.1074/mcp.M111.007898
DO - 10.1074/mcp.M111.007898
M3 - Article
C2 - 21372249
AN - SCOPUS:79955750270
VL - 10
JO - Molecular and Cellular Proteomics
JF - Molecular and Cellular Proteomics
SN - 1535-9476
IS - 5
ER -