Calu-3: a human airway epithelial cell line that shows cAMP-dependent Cl- secretion.
Of 12 cell lines derived from human lung cancers, only Calu-3 cells showed high transepithelial resistance (Rte) and increases in short-circuit current (Isc) in response to mediators. Calu-3 cells formed polarized monolayers with tight junctions and Rte of approximately 100 omega.cm2. Baseline Isc was approximately 35 microA/cm2 and was increased by approximately 75 microA/cm2 on elevation of intracellular adenosine 3',5'-cyclic monophosphate (cAMP) by isoproterenol. Flux studies showed that the increase in Isc was due to Cl- secretion. Forskolin and permeant analogues of cAMP also increased Isc. Consistent with the presence of cAMP-dependent Cl- secretion, immunoprecipitation demonstrated the presence of the cystic fibrosis transmembrane conductance regulator (CFTR). Bradykinin, methacholine, trypsin, and histamine all transiently (15-30 s) elevated Isc, probably by increasing intracellular Ca concentration. Experiments in which the basolateral membrane was permeabilized with nystatin indicated that CFTR was substantially activated under baseline conditions and that Ca-activated Cl- channels were absent from the apical membrane. We anticipate that Calu-3 cells will prove useful in the study of Cl- secretion and other functions of human airway epithelial cells.
Shen
B Q
BQ
Department of Physiology, University of California, San Francisco 94143.
Finkbeiner
W E
WE
Wine
J J
JJ
Mrsny
R J
RJ
Widdicombe
J H
JH
D001920:Bradykinin / Q000494:pharmacology; D002034:Bumetanide / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D002463:Cell Membrane Permeability; D018118:Chloride Channels / Q000032:analysis / Q000378:metabolism*; D002712:Chlorides / Q000378:metabolism*; D005576:Colforsin / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D003896:Desmosomes / Q000648:ultrastructure; D004848:Epithelium / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D007365:Intercellular Junctions / Q000502:physiology / Q000648:ultrastructure; D007545:Isoproterenol / Q000494:pharmacology*; D007700:Kinetics; D008175:Lung Neoplasms; D008565:Membrane Proteins / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D016210:Methacholine Chloride / Q000494:pharmacology; D008854:Microscopy, Electron; D009761:Nystatin / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism; D014357:Trypsin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
C505032:CFTR protein, human; D018118:Chloride Channels; D002712:Chlorides; D008565:Membrane Proteins; D016210:Methacholine Chloride; D002034:Bumetanide; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D009761:Nystatin; D005576:Colforsin; D000001:Calcimycin; D010042:Ouabain; D006632:Histamine; D012964:Sodium; D000242:Cyclic AMP; D014357:Trypsin; D007545:Isoproterenol; D001920:Bradykinin