Modulation of cellular cholesterol alters P-glycoprotein activity in multidrug-resistant cells
The drug transporter P-glycoprotein (ABCB1) plays an important role in drug distribution and elimination, and when overexpressed it may confer multidrug resistance (MDR). P-glycoprotein is localized in the plasma membrane, especially within rafts and caveolae, characterized as detergent-resistant me...
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| Main Authors: | , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
1 Nov 2004
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| In: |
Molecular pharmacology
Year: 2004, Volume: 66, Issue: 5, Pages: 1332-1339 |
| ISSN: | 1521-0111 |
| DOI: | 10.1124/mol.104.002329 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1124/mol.104.002329 Verlag, lizenzpflichtig, Volltext: https://molpharm.aspetjournals.org/content/66/5/1332 
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| Author Notes: | Joachim Troost, Heike Lindenmaier, Walter Emil Haefeli, and Johanna Weiss |
| Summary: | The drug transporter P-glycoprotein (ABCB1) plays an important role in drug distribution and elimination, and when overexpressed it may confer multidrug resistance (MDR). P-glycoprotein is localized in the plasma membrane, especially within rafts and caveolae, characterized as detergent-resistant membranes (DRMs). This study investigated the effect of cholesterol depletion and repletion as well as saturation on subcellular localization and function of P-glycoprotein to determine the effect of DRM localization on P-glycoprotein-mediated drug efflux. In L-MDR1 overexpressing human P-glycoprotein, cholesterol depletion removed P-glycoprotein from the raft membranes into non-DRM fractions, whereas repletion fully reconstituted raft localization. P-glycoprotein function was assessed by realtime monitoring with confocal laser scanning microscopy using BODIPY-verapamil as substrate. Cholesterol depletion reduced P-glycoprotein function in L-MDR1 cells resulting in intracellular substrate accumulation (159% ± 43, p < 0.001; control = 100%). Cholesterol repletion reduced intracellular substrate fluorescence (120% ± 36, p < 0.001) and restored the transporter activity. Addition of surplus cholesterol (saturation) even enhanced drug efflux in L-MDR1 cells, leading to reduced intracellular accumulation of BODIPY-verapamil (69% ± 10, p < 0.001). Transport of BODIPY-verapamil in cells not expressing human P-glycoprotein (LLC-PK1) was not susceptible to cholesterol alterations. These results demonstrate that cholesterol alterations influence P-glycoprotein localization and function, which might contribute to the large interindividual variability of P-glycoprotein activity known from in vivo studies. |
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| Item Description: | Gesehen am 19.05.2021 |
| Physical Description: | Online Resource |
| ISSN: | 1521-0111 |
| DOI: | 10.1124/mol.104.002329 |