Related Experiment Videos
P-glycoprotein expression in the Golgi apparatus of multidrug-resistant cells
A Molinari1, M Cianfriglia, S Meschini
1Laboratorio di Ultrastrutture, Istituto Superiore di Sanità, Rome, Italy.
Abstract:
The surface and intracellular expression of mdrI-P-glycoprotein in parental drug-sensitive human breast cancer cells (MCF-7) and their multidrug-resistant (MDR) variants has been studied by using the monoclonal antibodies (MAbs) MM4.17 and MRK-16, which recognize 2 different epitopes of the drug efflux pump molecule. Fluorescence microscopic observations showed that P-glycoprotein, in addition to being located at the cell surface, can also be found in the Golgi apparatus of resistant cells. To confirm this finding, Golgi apparatus and P-glycoprotein were double-labelled with wheat-germ agglutinin (WGA) and MAb MM4.17. Laser scanning confocal microscopy indicated that, in MDR cells, Adriamycin mainly accumulated cytoplasmically in a perinuclear region. This accumulation proved to be modulated by pre-treatment with verapamil or ATP depletion. Moreover, the vital staining of Adriamycin-treated MDR cells, performed with the fluorescent lipid N-[7-(4-nitrobenzo-2-oxa-1,3-diazole)]- 6-aminocaproyl sphingosine (C6-NBD-ceramide), revealed that the anthracyclinic antibiotic was located in the Golgi apparatus. All these results indicate that the drug transporter is located in the Golgi apparatus, in which Adriamycin molecules also accumulate.
Insights
Multidrug-resistant breast cancer cells exhibit P-glycoprotein in the Golgi apparatus, where Adriamycin accumulates. This finding suggests a new target for overcoming drug resistance in cancer therapy.
Area of Science:
- Cell Biology
- Molecular Biology
- Cancer Research
Background:
- Multidrug resistance (MDR) in cancer is a major challenge in chemotherapy.
- P-glycoprotein is a key efflux pump contributing to MDR.
- Understanding the intracellular localization of P-glycoprotein is crucial for developing strategies to overcome MDR.
Purpose of the Study:
- To investigate the surface and intracellular expression of P-glycoprotein in drug-sensitive and multidrug-resistant human breast cancer cells.
- To determine the subcellular localization of P-glycoprotein and its role in Adriamycin accumulation in MDR cells.
Main Methods:
- Utilized monoclonal antibodies (MAbs) MM4.17 and MRK-16 to detect P-glycoprotein.
- Employed fluorescence microscopy and laser scanning confocal microscopy.
- Performed double-labeling with wheat-germ agglutinin (WGA) and vital staining with C6-NBD-ceramide.
Main Results:
- P-glycoprotein was found not only on the cell surface but also within the Golgi apparatus of resistant cells.
- Adriamycin accumulated in the cytoplasm, specifically in a perinuclear region, within MDR cells.
- Confocal microscopy confirmed Adriamycin localization in the Golgi apparatus, modulated by verapamil or ATP depletion.
Conclusions:
- The drug transporter P-glycoprotein is localized in the Golgi apparatus.
- Adriamycin molecules accumulate within the Golgi apparatus in multidrug-resistant breast cancer cells.
- This intracellular localization may represent a novel target for overcoming P-glycoprotein-mediated multidrug resistance.