A survey of surface glycoproteins of four human squamous cell carcinoma lines

The major cell surface glycoprotein components of four new cell lines derived from human squamous cell carcinomas of the head and neck (TR126, TR131, TR138, TR146, Rupniak, H. T. et al., JNCI 75, 621-635, 1985) were identified by three complementary labelling methods. The profile of labelled glycoprotein components was very similar in the four cell lines, although quite large quantitative differences in individual bands were seen. Two galactoproteins, designated GPC-130 and GPC-80 (apparent molecular weight X 10(-3)) were labelled by galactose oxidase/NaB [3H]4 but in all four lines only GPC-130 was prominent. The cell surface galactose and N-Acetylgalactosaminyl residues of glycoproteins were quite highly sialylated, as the galactose oxidase/NaB [3H]4 reaction was increased by between 3- and 6-fold after neuraminidase treatment. The neuraminidase-galactose oxidase/NaB [3H]4 and NaIO4/NaB [3H]4 methods identified a complex profile of glycoprotein components, with very high molecular weight sialogalactoconjugates being prominent. The major sialoglycoproteins were GPC-205, GPC-175, GPC-155, GPC-90 and GPC-70 and in addition, GPC-130 and GPC-80 showed enhanced labelling. Lactoperoxidase catalyzed the iodination of a similar profile of high molecular weight glycoprotein components, with GPC-205 and GPC-175 being prominent in TR126, TR131 and TR146 but less evident in TR138. Overall, the profile of labelled glycoprotein components was similar to the pattern seen in the well differentiated transitional carcinoma lines RT112 and RT4 (Steele, J. G. et al., Biochim. Biophys. Acta. 732, 219-228, 1983).