title: Expression and activity of multidrug resistance proteins in mature endothelial cells and their precursors: A challenging correlation.
abstract: Active cellular transporters of harmful agents-multidrug resistance (mdr) proteins-are present in tumor, stem and endothelial cells, among others. While mdr proteins are broadly studied in tumor cells, their role in non-tumor cells and the significance of their action not connected with removal of harmful xenobiotics is less extensively documented. Proper assessment of mdr proteins expression is difficult. Mdr mRNA presence is most often evaluated but that does not necessarily correlate with the protein level. The protein expression itself is difficult to determine; usually cells with mdr overexpression are studied, not cells under physiological conditions, in which a low expression level of mdr protein is often insufficient for detection in vitro. Various methods are used to identify mdr mRNA and protein expression, together with functional tests demonstrating their biological drug transporting activities. Data comparing different methods of investigating expression of mdr mRNAs and their corresponding proteins are still scarce. In this article we present the results of a study concerning mdr mRNA and protein expression. Our goal was to search for the best method to investigate the expression level and functional activity of five selected mdr proteins-MDR1, BCRP, MRP1, MRP4 and MRP5-in established in vitro cell lines of human endothelial cells (ECs) and their progenitors. Endothelial cells demonstrated mdr presence at the mRNA level, which was not always confirmed at the protein level or in functional tests. Therefore, several different assays had to be applied for evaluation of mdr proteins expression and functions in endothelial cells. Among them functional tests seemed to be the most conclusive, although not very specific.
authors.affiliation: Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland.
authors.forename: Agnieszka
authors.identifier: http://orcid.org/0000-0003-4545-8843
authors.initials: A
authors.lastname: Krawczenko
authors.affiliation: Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Bielawska-Pohl
authors.affiliation: Department of Histology and Embryology, Poznan University of Medical Sciences, Poznan, Poland.
authors.forename: Karolina
authors.initials: K
authors.lastname: Wojtowicz
authors.affiliation: Wroclaw Research Centre EIT+, Wroclaw, Poland.
authors.forename: Roksana
authors.initials: R
authors.lastname: Jura
authors.affiliation: Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland.
authors.forename: Maria
authors.initials: M
authors.lastname: Paprocka
authors.affiliation: Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland.
authors.forename: Elżbieta
authors.initials: E
authors.lastname: Wojdat
authors.affiliation: Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland.
authors.forename: Urszula
authors.initials: U
authors.lastname: Kozłowska
authors.affiliation: Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Klimczak
authors.affiliation: Cellular Microenvironment and Pharmacological Targets, Centre de Biophysique Moléculaire, CNRS UPR 4301, Orléans, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Grillon
authors.affiliation: Cellular Microenvironment and Pharmacological Targets, Centre de Biophysique Moléculaire, CNRS UPR 4301, Orléans, France.
authors.forename: Claudine
authors.initials: C
authors.lastname: Kieda
authors.affiliation: Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland.
authors.forename: Danuta
authors.initials: D
authors.lastname: Duś
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000235:genetics* / Q000378:metabolism*; D002460:Cell Line; D005786:Gene Expression Regulation; D061307:Human Umbilical Vein Endothelial Cells / Q000166:cytology* / Q000378:metabolism*; D006801:Humans; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013234:Stem Cells / Q000378:metabolism*
chemical_list: D018435:ATP Binding Cassette Transporter, Subfamily B; D012333:RNA, Messenger