Establishment and characterization of normal and initiated hamster tracheal epithelial cell system

The development and characterization of normal hamster tracheal epithelial (HTE) cell system and its initiated subline is described in the present study. Normal HTE cells grew in a monolayer, had a stable diploid karyotype, were anchorage dependent and non-tumorigenic. The presence of desmosomal attachments and keratin filaments confirmed the epithelial nature of these cells. An initiated subline DTC8 was isolated after treatment of HTE cells with a suboptimal dose of 9,10-dimethyl-1,2-benz[a]anthracene (DMBA). These DTC8 cells grew in a monolayer, had a higher growth rate and saturation density, were weakly anchorage independent and non-tumorigenic. Treatment of DTC8 cells with 100 ng 12-O-tetradecanoyl phorbol-13-acetate (TPA), resulted in transformation of these cells which then showed anchorage independent growth on semisolid agar and formed tumours in 85% animals. As DTC8 cells showed heterogeneity in chromosome number, they were further cloned by the limiting dilution method using gamma-irradiated hamster embryonic fibroblasts as a feeder layer. The clone H7I, isolated among these clones had all the properties of initiated cells.