Immunoelectron microscopic investigation of surface coat of Wilms tumor cells. Dense lamina is composed of highly sialylated neural cell adhesion molecule.
In previous studies we demonstrated the presence of polysialic acid in Wilms tumor by immunohistochemistry and immunoblotting. We now show by immunoelectron microscopy that the cell surface coat of Wilms tumor cells consists of a layer of amorphous material containing polysialic acid but not detectable amounts of laminin, laminin-nidogen complex, or low density proteoglycan. Therefore, Wilms tumor cells are covered by a highly developed and chemically specialized cell surface coat that does not represent a basement membrane, although it bears some structural similarities. Polysialic acid is present on neural cell adhesion molecule that exists in Wilms tumor as two isoforms of approximately 120 and 140 kDa. The cell surface coat exhibits variation in its thickness along the plasma membrane of a single tumor cell, and the variation is inversely related to the extent of cell-cell contact. It is therefore proposed that polysialic acid may modulate the behavior and invasive potential of Wilms tumor cells.
Roth
J
J
Interdepartmental Electron Microscopy, University of Basel, Switzerland.
Zuber
C
C
D015816:Cell Adhesion Molecules, Neuronal / Q000032:analysis*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D007680:Kidney Neoplasms / Q000032:analysis* / Q000648:ultrastructure; D008854:Microscopy, Electron / Q000379:methods; D012794:Sialic Acids / Q000032:analysis*; D009396:Wilms Tumor / Q000032:analysis* / Q000648:ultrastructure
D015816:Cell Adhesion Molecules, Neuronal; D012794:Sialic Acids; C021319:polysialic acid