Heterogeneity of glycoprotein synthesis in human tumor cell lines

In order to screen human tumor cells for putative cell surface marker molecules, the glycoprotein composition of in vitro cultivated human tumor cell lines of different origin (12 carcinomas, one neuroblastoma, one melanoma and one sarcoma) was analyzed by metabolically labelling the cells with [3H]galactose, [3H]mannose and [3H]fucose and subsequently separating the labelled material by SDS-PAGE. The cell lines expressed their specific glycoprotein patterns. Strongly glycosylated proteins of apparent mol. wt 40-45 kD, 60-62 kD, 80-82 kD and 90-92 kD were shared by nearly all carcinoma cell lines studied. Apart from these glycoprotein clusters, a great diversity was observed between tumor cell lines derived from the same organ. Three bladder carcinoma cell lines had a 112-114 kD glycoprotein in common. Glycoprotein expression of these cell lines remained constant during 1 yr of in vitro culture. Hence, these glycoprotein patterns seem to be useful for monitoring the phenotypic stability of cell lines. A sarcoma cell line was deficient in incorporating fucose and showed strikingly different glycoprotein patterns compared to the other cell lines studied. The metabolic labelling procedure revealed a wide phenotypic heterogeneity of the human carcinoma cell lines concerning glycoprotein synthesis. This method contributes another parameter to map the major glycoprotein species of various types of carcinomas.