Ultrastructural Studies of Surface Features of Human Normal and Tumor Cells in Tissue Culture by Scanning and Transmission Electron Microscopy2

Abstract

Human tumors of a variety of histopathologic types have been established in tissue culture. The surface features of these cell lines were investigated by scanning electron microscopy (SEM) with the use of new techniques for specimen preparation. Tumor cells demonstrated striking degrees of surface activity with numerous microvilli, filopodia, blebs, and ruffles. Intercellular contacts were also prominent in cultures of most solid tumors observed by SEM. At low cell density, normal human fibroblasts exhibited some surface features such as microvilli and blebs, but at higher cell density they lacked extensive surface modifications. By transmission electron microscopy (TEM), the cytoskeleton of normal fibroblasts was shown to be well organized, with parallel orientation of microfilaments, filaments, and microtubules. These structures were also in tumor cells, but they lacked the degree of organization of fibroblasts. Desmosomes were readily demonstrated in normal fibroblasts and carcinoma cells in culture but not in sarcomas, melanomas, or tumors of neural origin. These studies have provided the first correlative SEM and TEM analyses of solid human tumor cells of diverse pathologic types in vitro.

Quantitative studies of hemidesmosomes during progressive DMBA carcinogenesis in hamster cheek-pouch mucosa

“…In previous reports (White et al, 1981;White & Gohari, 1981b) we have already described the presence of microfilaments in peripheral regions of transforming basal cells. These have also been found in carcinomas by Malech & Lentz (1974), Toli & Muller (1975), Gabbiani et al (1976), McNutt (1976 and Gonda et al (1976). The combination of features of peripheral microfilaments and hemidesmosomal loss has been described in basal keratinocytes during epidermal wound healing (Martinez, 1972), in which cells are actively migrating over collagenous tissue and under blood clot to reestablish epithelial continuity.…”

Human T-cell leukemia virus type 1 p8 protein increases cellular conduits and virus transmission

“…After 1 h coculture, cells were fixed with 0.1% glutaraldehyde 4% paraformaldehyde in 0.1 M Sorensen buffer (pH 7.2) for 10 min at 37°C. The samples were processed as previously described (47).…”

ArfGAP1 promotes COPI vesicle formation by facilitating coatomer polymerization

“…76 Briefly, the cells were fixed overlaying 2% glutaraldehyde 77,78 in sodium cacodylate buffer (0.1 M, pH 7.0) for 1 h, replaced with same buffer, and post-fixed in 1% osmium tetroxide (Electron Microscopy Sciences). The cells were en bloc stained in 0.5% uranyl acetate in acetate buffer (0.1 M pH 4.5) for 1 h. The cells were rinsed in acetate buffer and dehydrated in a grade of ethanol (e.g., 35%, 50%, 75%, 95% and 100%).…”