Characterization of multidrug transporters in a normal renal tubular cell line resistant to doxorubicin. Multidrug transporters in the LLC-PK(1) cell line and its resistant counterpart.
LLC-PK(1) is a proximal tubular cell line derived from normal pig kidney which has a structure and function similar to those of renal proximal tubular cells and which expresses baseline levels of P-glycoprotein. We isolated by drug selection a doxorubicin-resistant cell line (LLC-PK(1)/ADR) that exhibited a multidrug-resistant phenotype; this cell line was characterized by reduced intracellular drug concentrations, an increased drug extrusion, and increased expression of a 170-kDa P-glycoprotein detected by Western blot analysis with monoclonal antibody C219. In addition, an increased expression of MDR1 mRNA was seen by reverse transcriptase-polymerase chain reaction. These results suggest that it is possible to induce the overexpression of P-glycoprotein by chronic treatment with doxorubicin in a normal cell line that physiologically expresses low levels of this protein. This multi-resistant cell line could provide an interesting model for studying the role of P-glycoprotein and the consequence of its induction in a normal tissue.
Decorti
G
G
Department of Biomedical Sciences, University of Trieste, I-34127, Trieste, Italy. decorti@univ.trieste.it
Rosati
A
A
Candussio
L
L
Giraldi
T
T
Bartoli Klugmann
F
F
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D004317:Doxorubicin / Q000494:pharmacology*; D018432:Drug Resistance, Multiple; D005456:Fluorescent Dyes / Q000493:pharmacokinetics; D015870:Gene Expression / Q000187:drug effects; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D020112:Rhodamine 123 / Q000493:pharmacokinetics; D013552:Swine
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D005456:Fluorescent Dyes; D020112:Rhodamine 123; D004317:Doxorubicin