Influence of Different Chemicals on MDR-1 P-Glycoprotein Expression and Activity in the HK-2 Proximal Tubular Cell Line
| Autor: | Elisabetta Chieli, Gianfranco Tramonti, Nadia Romiti |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
medicine.medical_specialty
endocrine system diseases Blotting Western Biology Toxicology Kidney Tubules Proximal Internal medicine Cyclosporin a polycyclic compounds medicine Humans ATP Binding Cassette Transporter Subfamily B Member 1 RNA Messenger Cell Line Transformed DNA Primers P-glycoprotein Pharmacology Base Sequence integumentary system Reverse Transcriptase Polymerase Chain Reaction Membrane transport Molecular biology female genital diseases and pregnancy complications In vitro carbohydrates (lipids) Blot Endocrinology Gene Expression Regulation Cell culture biology.protein Electrophoresis Polyacrylamide Gel Immortalised cell line Intracellular |
| Zdroj: | Toxicology and Applied Pharmacology. 183:83-91 |
| ISSN: | 0041-008X |
| DOI: | 10.1006/taap.2002.9461 |
| Popis: | P-glycoprotein (Pgp), the MDR-encoded membrane transporter, is physiologically expressed in normal tissues with excretory functions, including kidney proximal tubules. In a preliminary report we have shown that HK-2, an immortalized cell line from normal human proximal tubule, expresses a functional Pgp and may be considered a valuable model for in vitro investigations on the Pgp role(s) in human renal pathophysiology. The present investigation was designed to further characterize the properties of HK-2 Pgp by exploring its responsiveness to a variety of exogenous or endogenous modulators. HK-2 cells were cultured in Dulbecco's modified Eagle's medium/Ham's F-12 supplemented with 5% FCS in the absence or in the presence of modulators. Pgp mRNA expression was studied by RT-PCR and the amount of Pgp was determined by Western blotting. Pgp activity was assessed by intracellular rhodamine-123 (R-123) accumulation. RT-PCR showed that HK-2 cells express MDR-1, but not MDR-3. Both MDR-1 Pgp and MDR-1 mRNA were significantly increased in cells cultured in the presence of cyclosporin A (CsA), 1,25(OH)(2)D(3), platelet activating factor, dexamethasone (Dex), or aldosterone. Verapamil (Vp), cimetidine, and trimethoprim did not affect HK-2 Pgp expression. Conversely, 2-acetylaminofluorene strongly downregulated Pgp expression. Vp, CsA, 1,25(OH)(2)D(3) and Dex significantly increased R-123 intracellular retention, indicating the inhibition of Pgp-mediated transport. Drug-pretreated, Pgp-overexpressing cells showed increased Pgp activity and were less susceptible to toxic concentrations of CsA. MDR-1 Pgp in HK-2 appears to be responsive to many compounds, including classical Pgp inhibitors and putative physiological substrates, but some of its pharmacological properties are different from those described in other experimental, in particular nonhuman, cell models. |
| Databáze: | OpenAIRE |
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