Analysis of mRNA for ABC‐, SLC‐ and SLCO‐transporter in human respiratory epithelial cells

Abstract

The role of transporter proteins in drug disposition in the lung remains mostly unknown to date. Here, RT‐PCR is used to determine the presence of mRNA transcripts for drug transporters in human lung epithelial cell models. In the cell lines, A549, Calu‐3 and 16HBE14o‐, expression of mRNA transcripts for all ABC‐transporters tested, except for MRP8, was found, while in hBEpC and hAEpC, mRNA transcripts for all ABC‐transporters were present. When the cell lines were examined for expression of SLC‐transporters, all tested cells were found positive for OCT1, OCTN2 and PEPT2. PEPT1, OCTN1 and OAT4 expression was noted in all cells, except hBEpC. OCT3 was positively identified in A549, Calu‐3 and hBEpC. None of the cells showed positive transcripts for OCT2, OAT1, ‐2 and ‐3. Levels of SLCO transcripts varied between all cell lines tested, although none were found in 16HBE14o‐. Transcripts for OATP3A1 and OATP4A1 were found in all other cell lines. Additionally to A549 and Calu‐3, mRNA for OATP5A1 and OATP1B3 was found in BEAS‐2B and for OATP1A2 in BEAS‐2B and hBEpC, whereas mRNA for OATP1B1 and OATP1C1 was only detected in A549 and Calu‐3. This study shows that there are significant differences in the expression pattern of ABC‐, SLC‐ and SLCO‐transporters between cell types of the respiratory epithelium. These data are essential for the appropriate use and interpretation of in vitro data obtained with the described cell cultures.