[Effect of cell surface sialic acid and their linkages on adhesion of mammary carcinoma cells].
OBJECTIVE
To investigate the effect of cell surface sialic acid and its linkage on the cell-cell and cell-matrix adhesion of mammary carcinoma cells MD-MB-435.


METHODS
MD-MB-435 cells were sense-transfected with ST6Gal I cDNA or antisense-transfected with part of the ST6Gal I sequence inserted in pcDNA 3.1 vector, with mock transfection with pcDNA3.1 vector as the control. The cell surface alpha2, 6-linked sialylation was determined by fluorescence-activated cell sorting (FACS) using lectin SNA (Sambucus nigra agglutinin specific to alpha2, 6-linked sialic acid on N-linked glycoprotein). A significantly increased alpha2, 6-sialylation subclone in sense-transfectants and a decreased alpha2, 6-sialylation subclone in antisense-transfectants were selected for further examination of cell-cell and cell-matrix (collagen IV) adhesion. The transfectants were also treated with sialidase to compare the capacity of cell adhesion affected by cell surface sialylation.


RESULTS
Sense-transfection subclone showed a reduced cell-cell aggregation but enhanced cell-matrix adhesion. In contrast, the antisense-transfection subclone exhibited increased cell-cell aggregation and decreased cell-matrix adhesion. After treatment with sialidase, the cell-matrix adhesion of all the transfectants and the parental MDA-MB-435 cells were significantly reduced to the level of 31%-57% of untreated cells.


CONCLUSIONS
Cell surface sialic acid and alpha2, 6-linked sialylation play an important role in cell-cell and cell-matrix adhesion of mammary carcinoma cell MDA-MB-435.
Wang
Xiao-yu
XY
Department of Obstetrics and Gynecology, First Affiliated Hospital of Ji'nan University, Guangzhou 510630, China.
Lin
Shao-qiang
SQ
Li
Jun-wu
JW
Kemmner
Wolfgang
W
Ding
Yan-qing
YQ
D015703:Antigens, CD / Q000235:genetics* / Q000378:metabolism; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism*; D021982:Cell-Matrix Junctions / Q000378:metabolism; D024141:Collagen Type IV / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism; D006801:Humans; D019158:N-Acetylneuraminic Acid / Q000378:metabolism*; D012799:Sialyltransferases / Q000235:genetics* / Q000378:metabolism; D014162:Transfection; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase
D015703:Antigens, CD; D024141:Collagen Type IV; D012799:Sialyltransferases; D019158:N-Acetylneuraminic Acid; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase