Expression of airway secretory epithelial functions by lung carcinoma cells.

We examined 12 non-small cell lung carcinoma cell lines for expression of airway goblet, serous, and mucous cell characteristics. The cells expressed some ultrastructural traits of secretory epithelial cells but none contained secretory granules typical of the airway secretory cells. Using immunocytochemistry and cell-specific monoclonal antibodies, we identified heterogeneous expression of goblet, mucous, and serous cell markers among the cell lines. After metabolic radiolabeling, cells incorporated isotope into high molecular weight material. Incubation of pulse-radiolabeled cells with a number of known mucus secretogogues revealed that 5 of the 12 cell lines released radiolabeled material in response to the agonists. However, in each cell line only one of the receptor-activated pathways tested was intact. Although we did not identify a single cell line expressing a phenotype similar to normal airway secretory cells, particular functions retained by some of these cell lines may make them useful for specific studies of mucus production or secretion.

Reverse transcription-polymerase chain reaction (RT-PCR) phenotypic analysis of cell cultures of human tracheal epithelium, tracheobronchial glands, and lung carcinomas.

In order to identify expression of RNA transcripts for a number of important tracheobronchial cell products and molecules, we developed simple reverse transcription-polymerase chain reaction (RT-PCR) assays. Assays included the RNA for two apomucins (MUC1 and MUC2), secretory component, secretory leukocyte inhibitor protein, lysozyme, lactoferrin, 15-lipoxygenase, and the cystic fibrosis transmembrane conductance regulator. We tested RNA of normal and neoplastic origin. Sources of normal tissue included human tracheal surface epithelial cells and tracheobronchial submucosal tissues, acutely isolated human tracheal surface epithelial and tracheobronchial gland acini, and confluent cultures of human tracheal epithelial and tracheobronchial gland cells. Sources of neoplastic tissue included cell lines of non-small cell carcinomas of the lung. RNA expression was correlated with protein expression as assessed by immunocytochemistry. Tracheal surface epithelial tissues, isolated cells and cultures, and tracheobronchial submucosal tissues expressed RNA transcripts for all of the RNA transcripts assayed. Isolated gland acini and cultured gland cells expressed all RNA transcripts except 15-lipoxygenase. Expression of RNA transcripts by non-small cell lung carcinomas was heterogeneous and not necessarily influenced by histopathologic type. In most instances, RNA expression predicted expression of immunocytochemically detectable protein. These RT-PCR assays are useful for characterizing the molecular phenotype of cell cultures derived from normal or neoplastic airway epithelium and for establishing the potential of cultured cells for functional studies.