Isolation and spontaneous transformation of cloned lines of hamster tracheal epithelial cells

Abstract

In respiratory carcinogenesis studies using rodents, the tracheal epithelium is the target tissue for the induction of tumors after exposure of animals to chemical carcinogens. In the studies described below, tracheal epithelial cells were isolated to evaluate their biological and biochemical features. Epithelial cells derived from the tracheal mucosa of Syrian golden hamsters were established in culture. Three morphological types of polygonal cells were observed as mixed populations in four clonally derived lines. One type of cell is mucin secreting since membrane-bound vesicles that stain positively using the alcian blue:periodic acid-Schiff reaction are present in the cytoplasm and increased amounts of mucin constituents are demonstrable in the culture medium. Cells of a second type possess both intracytoplasmic and surface cilia, but they lack mucin vesicles. The third type exhibits no differentiating features. Four density-dependent inhibited cloned cell lines were established. After repeated passage, these cells: (a) grew in soft agar; (b) released proteases that were activators of plasminogen; (c) demonstrated measurable basal and inducible aryl hydrocarbon hydroxylase activity; and (d) produced anaplastic carcinomas in syngeneic hamsters. Factors affecting the transformation and differentiation of respiratory epithelial cells have not been elucidated. The availability of these cell lines will permit studies that focus on these questions.