P-glycoprotein Mediates Drug Resistance via a Novel Mechanism Involving Lysosomal Sequestration
| Autor: | Tetsuo Yamagishi, Sumit Sahni, Akanksha Arvind, Danae M. Sharp, Patric J. Jansson, Des R. Richardson |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
ATP Binding Cassette Transporter
Subfamily B endocrine system diseases Daunorubicin Antineoplastic Agents Biochemistry chemistry.chemical_compound Cell Line Tumor Lysosomal-Associated Membrane Protein 2 polycyclic compounds medicine Humans Doxorubicin ATP Binding Cassette Transporter Subfamily B Member 1 Molecular Biology P-glycoprotein Cisplatin integumentary system biology Lysosome-Associated Membrane Glycoproteins Cell Biology Hydrogen-Ion Concentration female genital diseases and pregnancy complications Neoplasm Proteins Cell biology Gene Expression Regulation Neoplastic carbohydrates (lipids) Multiple drug resistance chemistry Paclitaxel Drug Resistance Neoplasm biology.protein Valspodar Lysosomes Intracellular medicine.drug |
| Zdroj: | Journal of Biological Chemistry. 288:31761-31771 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m113.514091 |
| Popis: | Localization of the drug transporter P-glycoprotein (Pgp) to the plasma membrane is thought to be the only contributor of Pgp-mediated multidrug resistance (MDR). However, very little work has focused on the contribution of Pgp expressed in intracellular organelles to drug resistance. This investigation describes an additional mechanism for understanding how lysosomal Pgp contributes to MDR. These studies were performed using Pgp-expressing MDR cells and their non-resistant counterparts. Using confocal microscopy and lysosomal fractionation, we demonstrated that intracellular Pgp was localized to LAMP2-stained lysosomes. In Pgp-expressing cells, the Pgp substrate doxorubicin (DOX) became sequestered in LAMP2-stained lysosomes, but this was not observed in non-Pgp-expressing cells. Moreover, lysosomal Pgp was demonstrated to be functional because DOX accumulation in this organelle was prevented upon incubation with the established Pgp inhibitors valspodar or elacridar or by silencing Pgp expression with siRNA. Importantly, to elicit drug resistance via lysosomes, the cytotoxic chemotherapeutics (e.g. DOX, daunorubicin, or vinblastine) were required to be Pgp substrates and also ionized at lysosomal pH (pH 5), resulting in them being sequestered and trapped in lysosomes. This property was demonstrated using lysosomotropic weak bases (NH4Cl, chloroquine, or methylamine) that increased lysosomal pH and sensitized only Pgp-expressing cells to such cytotoxic drugs. Consequently, a lysosomal Pgp-mediated mechanism of MDR was not found for non-ionizable Pgp substrates (e.g. colchicine or paclitaxel) or ionizable non-Pgp substrates (e.g. cisplatin or carboplatin). Together, these studies reveal a new mechanism where Pgp-mediated lysosomal sequestration of chemotherapeutics leads to MDR that is amenable to therapeutic exploitation. |
| Databáze: | OpenAIRE |
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