Galactosyl Transferase Activity in Human Transitional Cell Carcinoma Lines and in Benign and Neoplastic Human Bladder Epithelium 1

Cultured cells of human transitional cell carcinoma line MGH-U1, in suspension, were assayed for galactosyl transferase by measurement of the transfer of [3 H]galactose from uridine diphosphate:[3 H]galactose to desialylated ovine submaxillary mucin. The assay was optimized with respect to time and to protein, uridine disphosphate:galactose, desialylated ovine submaxillary mucin, and Triton X-100 concentrations. This assay was then applied to fresh specimens of benign, inflamed, and neoplastic bladder epithelium from 33 patients who underwent cold-cup biopsies at cystoscopy. Transitional cell carcinoma specimens gave values in the range of 24.7 to 184.8 cpm [³H]galactose transferred per ¼g protein per hr [72.0 ± 44.7 (S.D.); n = 25]; normal and inflamed specimens ranged from 0.8 to 46.1 cpm/μg protein per hr [8.3 ± 8.4 (S.D.); n = 35]. By using a known method of cell rupture, cell ghosts, representing cell-surface membranes, were isolated both from the cultured cell line and from two biopsy specimens of transitional cell carcinoma. Although a complete enzymatic and electron microscopic analysis was not undertaken, the coincidence of an enzyme marker with the cell ghost fraction containing the elevated galactosyl transferase made it appear probable that this enzyme is located in the cell surface.