RT Journal Article
SR Electronic
T1 Endogenous Gene and Protein Expression of Drug-Transporting Proteins in Cell Lines Routinely Used in Drug Discovery Programs
JF Drug Metabolism and Disposition
JO Drug Metab Dispos
FD American Society for Pharmacology and Experimental Therapeutics
SP 2275
OP 2283
DO 10.1124/dmd.109.028654
VO 37
IS 12
A1 Gustav Ahlin
A1 Constanze Hilgendorf
A1 Johan Karlsson
A1 Cristina Al-Khalili Szigyarto
A1 Mathias Uhlén
A1 Per Artursson
YR 2009
UL http://dmd.aspetjournals.org/content/37/12/2275.abstract
AB The aim of this study was to investigate the gene and protein expression profiles of important drug-transporting proteins in human cell lines commonly used for studies of drug transport mechanisms. Human cell lines used to transiently or stably express single transporters [HeLa, human embryonic kidney (HEK) 293] and leukemia cell lines used to study drug resistance by ATP-binding cassette transporters (HL-60, K562) were investigated and compared with organotypic cell lines (HepG2, Saos-2, Caco-2, and Caco-2 TC7). For gene expression studies, real-time polymerase chain reaction was used, whereas monospecific polyclonal antibodies were generated and used to investigate protein expression by immunohistochemistry. Thirty-six transporters were studied for gene expression, and nine were studied for protein expression. The antibodies were validated using expression patterns in human tissues. Finally, the function of one ubiquitously expressed transporter, MCT1/SLC16A1, was investigated using [14C]lactic acid as a substrate. In general, the adherent cell lines (HeLa, HEK293) displayed low transporter expression, and the expression patterns were barely affected by transfection. The leukemia cell lines (K562, HL-60) and Saos-2 also had low endogenous transporter expression, whereas the organotypic cell lines (HepG2 and Caco-2) showed higher expression of some transporters. Comparison of gene and protein expression profiles gave poor correlations, but better agreement was obtained for antibodies with a good validation score, indicating that antibody quality was a significant variable. It is noteworthy that the monocarboxylic acid-transporting protein MCT1 was significantly expressed in all and was functional in most of the cell lines, indicating that MCT1 may be a confounding factor when the transport of small anionic drugs is investigated.Copyright © 2009 by The American Society for Pharmacology and Experimental Therapeutics