Affiliations: Department for Immunochemistry and Glycobiology,
Institute for the Application of Nuclear Energy – INEP, University of
Belgrade, Belgrade, Serbia
Note: [] Corresponding author: Miroslava Jankovic, University of
Belgrade, Institute for the Application of Nuclear Energy – INEP, Department
for Immunochemistry and Glycobiology, Banatska 31b, 11080 Zemun – Belgrade,
Serbia. Tel.: +381 11 2199 949; Fax: +381 11 2682 743; E-mail: [email protected]
Abstract: This study was aimed at obtaining insight into the diversity of
sialic acids in cancer- and non-cancer-related CA125 antigen, tumour marker of
serous ovarian cancer. Starting from available data suggesting the possible
relevance of sialic acids for discriminating CA125 antigens of different
origin, we have employed a new experimental approach based on the use of human
sialic acid-binding Ig-like lectins, Siglecs, as tools for the investigation of
sialylation. Siglec-2, belonging to the group of evolutionarily conserved
Siglecs, and Siglec-3, −6, −7,
−9 and −10, which are CD33-like Siglecs,
were probed in solid-phase binding assays with cancer-related CA125 antigens
from pleural fluid of patients with ovarian carcinoma (pfCA125), the OVCAR-3
ovarian carcinoma cell line (clCA125) and a non-cancer-related CA125 antigen,
i.e. pregnancy-associated pCA125 antigen. All Siglecs used showed detectable
binding to pCA125 antigen. Siglec-3, Siglec-7 and Siglec-2 exhibited
moderately stronger binding to pCA125 antigen than the others. In contrast to
this, Siglec-2 and Siglec-3 preferentially recognized pfCA125 with greater
total binding than for pCA125, whereas Siglec-9 and Siglec-10 were highly
selective for clCA125. Siglecs promise to be powerful tools for discriminating
CA125 of different origin and could propagate further research on other
molecular markers of biomedical and diagnostic importance.
