Cell surface changes associated with malignant transformation of bladder epithelium in vitro

Three properties of cell surface membranes of normal bladder epithelium and of two malignant urothelial lines transformed in vitro by Dr. Y. Hashimoto and Dr. H. S. Kitagawa were analyzed by means of morphological and chemical tools. Under scan electron microscopy, normal bladder epithelium displayed an appearance devoid of the pleomorphic, abundantly distributed, microvillous structures seen on the neoplastic cells. The molecular weight profiles of proteins dispersed from purified plasma membrane fractions demonstrated quantitative differences in the content of three molecular-weight classes between the native and the transformed cells. More striking differences were seen upon two-dimensional analysis of proteins solubilized from these two cell types, using 3 M KCl. These findings suggest that further investigations of the chemical moieties appearing on the cell surface early after transformation may enhance our understanding of proteins amenable for chemical and/or immunological attack to achieve control of the progression of bladder neoplasia.