Cytochemical staining for beta 1,6 branching of asparagine-linked oligosaccharides in variants of metastatic human colon carcinoma cells.

A positive correlation between tumor progression in human colon and increased beta 1,6 branching in oligosaccharides has recently been demonstrated. The present study was undertaken to elucidate whether such a correlation can be extended to variants of metastasizing human colon carcinoma HCT116 cells. The Phaseolus vulgaris leukoagglutinating lectin, which binds to beta 1,6 branched oligosaccharides, was employed. In blots, a band of approximately 140 kd was detectable in both the HCT116a and HCT116b sublines. However, in the more aggressive subline HCT116a, the intensity of this band was increased by 100%, and additional reactive bands of approximately 100 kd and approximately 170 kd were observed. Analysis by electron microscopy revealed lectin labeling in the Golgi apparatus, lysosomal elements, mucus droplets, cytoplasmic vesicles, and at the plasma membrane. Quantification of the lectin plasma membrane labeling revealed a significantly higher labeling intensity in HCT116a cells than in HCT116b cells. The difference in lectin plasma membrane labeling intensity could also be observed in paraffin sections. Thus, variants of metastatic HCT116 colon carcinoma cells differ quantitatively and qualitatively in glycoproteins carrying beta 1,6 branches.