EXPOSURE OF ORGAN-CULTURES FROM HUMAN TRACHEAL EPITHELIUM TO CHEMICALCARCINOGENS AND SUBSEQUENT LONG-TERM COCULTIVATION WITH AUTOLOGOUS ISOTOPIC FIBROBLASTS

As a continuation of previous experiments introducing an extracorporea l model for transformation of human respiratory epithelium that might be able to mimic a spontaneously occurring malignant tumor, we prepare d organ cultures from tracheal specimens and exposed them repeatedly t o chemical carcinogens, using benzo(a)pyrene and methylnitronitrosogua nine for 6 weeks. We then tried to select possibly initiated cells by subsequent co-cultivation with autologous isotopic fibroblasts for 2 y ears. Non-treated controls were maintained from the same specimens and cultured in the same manner. By this technique we selected from speci men La24 three long-living cell lines with varying morphology and an a ntigenic pattern indicating dedifferentiation. The cells expressed sim ultaneously a panel of cytokeratins, vimentin and neuroectodermal anti gens. Transplantation of these cell lines under the subrenal capsule o f athymic mice resulted in tumorlike nodules of limited size. Success rate was dependent on time of previous in vitro culture and carcinogen treatment. None of the lines produced invasive or metastasizing tumor s.