calcitonin and Adenocarcinoma

An in vitro cultured monolayer system of alveolar epithelial cells was used as a model to investigate the transport pathway of the peptides and proteins, salmon calcitonin (sCT), insulin (INS), recombinant hirudin (rHAV2), and recombinant human growth hormone (rhGH), in pulmonary epithelium. Human lung adenocarcinoma A549 cells formed continuous monolayers when grown on the polycarbonate filters of Transwell plates. The transport of the peptides and proteins having MW of 3400-22,000 Da was studied under different conditions. The results showed that the apparent permeability coefficients (P(app)) of these macromolecules across A549 cell monolayers ranged from 2x10(-6) to 5x10(-6) cm s(-1) and exhibited a good inverse correlation with molecular weight. No concentration, direction, or temperature dependence was observed in the permeation of sCT, INS, and rHAV2. While the P(app) of rhGH in the BA direction (2.25x10(-6) cm s(-1)) was less than that in the AB direction at both concentrations (3.20x10(-6) and 3.29x10(-6) cm s(-1)). The P(app) values of rhGH were concentration and temperature independent in the AB direction. These findings suggest that the hydrophilic peptides and proteins used in this study, sCT, INS, rHAV2, and rhGH, appear to cross the A549 cell monolayers via a paracellular pathway by a passive diffusion mechanism.

Topics: Adenocarcinoma; Biological Transport; Calcitonin; Hirudins; Humans; Insulin; Molecular Weight; Peptides; Permeability; Proteins; Pulmonary Alveoli; Tumor Cells, Cultured

An in vitro cultured monolayer system of alveolar epithelial cells was used as a model to investigate the transport pathway peptides or proteins, salmon calcitonin (sCT), insulin (INS), recombinant hirudin (rHAV2), and recombinant human growth hormone (rhGH), in pulmonary epithelium in vivo.. Human lung adenocarcinoma A549 cells formed continuous monolayers with growing polycarbonate filters of Transwell plate. Transport studies of macromolecules in the monolayer system were carried out after 6 days in culture. The transport of peptides or proteins with MW 3,400 - 22,000 was studied in cultured human lung adenocarcinoma A549 cell monolayers at different conditions.. The results showed that the apparent permeability coefficients (Papp) of these macromolecules across A549 cell monolayers ranged from 2 x 10(-6) to 5 x 10(-6) cm x s(-1) and exhibited good inverse correlation with molecule weight. No concentration, direction and temperature dependence were observed in the permeation of sCT, INS and rHAV2. While the Papp of rhGH in the BA direction (2.25 x 10(-6) cm x s(-1)) was significantly less than that in the reverse direction. The Papp values of rhGH were concentration and temperature independent in the AB direction.. These findings suggest that the hydrophilic peptides and proteins, salmon calcitonin, insulin, recombinant hirudin, and recombinant human growth hormone used in this study, appeared to penetrate the A549 cell monolayers via a paracellular pathway by passive diffusion mechanism.

Topics: Adenocarcinoma; Biological Transport; Calcitonin; Cell Line, Tumor; Epithelial Cells; Hirudins; Human Growth Hormone; Humans; Insulin; Lung Neoplasms; Peptides; Permeability; Proteins; Pulmonary Alveoli