The spectrum of human lung cancer cells in culture: a potential model for studying molecular determinants of tumor progression and metastasis.

We have reviewed the behavior of human lung cancer cells in culture. We have considered the implications of cell biology and biochemistry studies of the cultured cells for the in vivo behavior of lung neoplasms, including the metastatic potential of the different tumor types. Among the human lung cancers, SCC, which grows in culture as suspended aggregates of adherent cells, metastasizes earlier in the life cycle of the tumor and more widely than the major types of non-SCC lung cancers. These latter tumors grow as anchorage-dependent cells in culture. We have pointed out that ultrastructural studies of cultured human lung cancer cells reveal dramatic changes in cell surface membrane morphology coincident with progressive loss of SCC features and intercellular adhesion. We have stressed the potential value of these cultures of human lung cancer cells for studying the molecular determinants of intercellular adhesion and their importance to the process of metastasis. In this context, we have stressed that a different cell surface protein phenotype exists between SCC and non-SCC lung cancer cells in culture and that some of these proteins could be intimately involved in the different growth behavior patterns of these tumor cells. Finally, we have pointed out the need to construct models in which the growth characteristics and biochemical properties of cultured lung cancer cells can be directly compared in vivo with their metastatic potential.