Growth behavior of low passage cultured cells derived from human non-small cell lung carcinoma in deepithelialized rat tracheas transplanted into nude mice.

Proliferation behavior of six low passage cell lines derived from human non-small cell lung carcinoma was investigated both by cell inoculation into deepithelialized Fisher 344 rat tracheas xenotransplanted into nude mice and by direct cell injection into the subcutis of nude mice. In the tracheal transplants, all the cell lines showed a comparable or higher degree of differentiation than in the primary lesion, while most cell lines showed a lower degree of differentiation in the mouse subcutis. The surfaces of the tracheal transplants repopulated with the cells derived from squamous cell carcinomas were initially lined with a layer of flattened cells, two to three cells thick, while those repopulated with the cells from the three adenocarcinoma cases (HKT-3, HKT-5, HKT-6) were initially lined with simple epithelia comprising cuboidal-, round-and columnar-shaped cells, respectively. Subsequently, the cells from HKT-3 increased in height and proliferated in a pseudostratified pattern, those from HKT-5 proliferated in a papillary growth pattern and those from HKT-6 proliferated in a cribriform pattern. Ultrastructurally, they resembled ciliated bronchial epithelial cells, non-ciliated bronchiolar epithelial cells and bronchial goblet cells, respectively. Histological examination of cultured cells using this system was considered to be advantageous in the evaluation of differentiation since it provided unique proliferation patterns unobserved in primary tumors or tumors formed after s.c. direct cell injections.