Calu-3 cells grown under AIC and LCC conditions: Implications for dipeptide uptake and transepithelial transport of substances

Abstract

The aim of the present study was to investigate whether Calu-3 cell culture conditions influence drug and nutrient transport known to occur via carriers or transporters. Calu-3 cell layers, an in vitro model of the lung epithelium, were cultured using air interfaced culture (AIC) or liquid covered culture (LCC) on either polycarbonate or polyester as filter support material. We found that the development of the Calu-3 cell layer barrier function did not depend on the filter material but rather on the culture conditions as follows: (i) the apical uptake of Gly-Sar was significantly larger for cells grown in AIC compared to LCC, (ii) the TEER values for cells grown in LCC were approximately three times larger than for cells grown in AIC, (iii) the transepithelial transport in both AIC and LCC Calu-3 cells was polarized in the apical–basolateral direction of proline, glycine, α-methyl- d-glucoside, glipizide, taurocholic acid and estrone-3-sulfate, whereas inulin, mannitol and Gly-Sar showed no polarized transport. Etoposide showed polarized efflux (basolateral to apical transport) in AIC and LCC Calu-3 layers. These findings provide information about nutrient and drug transport in Calu-3 cells, and this may have implications for selecting culture conditions for transport studies in this in vitro model of the lung epithelium.