| 摘要 |
<p>The present invention relates to novel continuous human adenocarcinoma cell lines of epithelial lung tissue origin that produce fully processed or semi-processed surfactant-associated proteins, e.g., SAP-35 and SPL(Phe). The surfactant-associated proteins confer biological activity to pulmonary surfactant phospholipids and are useful for formulating pulmonary surfactant replacement for, inter alia, diagnosis and therapy of human diseases associated with surfactant deficiency. Exemplary cell lines of the present invention designated as NCI-H441-4, NCI-H820, NCI-H322 and NCI-H1404 are deposited with the American Type Culture Collection (ATCC) of Rockville, Maryland under accession Nos. CRL 9400, CRL 9531, CRL 9532 and CRL 9533, respectively. The present invention also relates to a novel method for regulating the expression of a surfactant-associated protein by cells having the ability to express at least one surfactant-associated protein and/or mRNA encoding therefore by exposing the cells to a regulating agent, such as a glucocorticoid hormone, 8-Br-cAMP or a functional equivalent, to selectively induce or inhibit the expression of a surfactant-associated protein. The present invention is also directed to novel methods to screen for tumor cells of pulmonary epithelial origin which produce surfactant-associated proteins and purifying the proteins from lysates of the cells or the media. The present invention also relates to novel human proteins, Mr=40-46,000, Mr=27-33,000 and Mr=23,000 on SDS-PAGE, which are believed to be precursors of the SPL(Phe) human protein. The SPL(Phe) mRNA initially translates an Mr=40-42,000 preproprotein which is glycosylated at asparagine residues and sialylated resulting in an Mr=40-46,000 SPL(Phe) proprotein. The Mr=27-33,000 protein is a proteolytically cleaved fragment of the Mr=40-46,000 precursor, and the Mr=23,000 protein results from de-glycosylating and de-sialylating the Mr=27-33,000 protein.</p> |
