Cellular and biochemical characterization of VX-710 as a chemosensitizer: reversal of P-glycoprotein-mediated multidrug resistance in vitro

• Published in: Anti-cancer drugs Vol. 8; no. 2; p. 125
• Main Authors: Germann, U A, Shlyakhter, D, Mason, V S, Zelle, R E, Duffy, J P, Galullo, V, Armistead, D M, Saunders, J O, Boger, J, Harding, M W
• Format: Journal Article
• Language: English
• Published: England 01-02-1997
• Subjects: Adenosine Triphosphatases - drug effects; Adenosine Triphosphatases - metabolism; Affinity Labels; Animals; Antineoplastic Agents - pharmacology; ATP-Binding Cassette, Sub-Family B, Member 1 - chemistry; ATP-Binding Cassette, Sub-Family B, Member 1 - drug effects; ATP-Binding Cassette, Sub-Family B, Member 1 - genetics; ATP-Binding Cassette, Sub-Family B, Member 1 - physiology; Carrier Proteins - drug effects; Carrier Proteins - metabolism; DNA-Binding Proteins - drug effects; DNA-Binding Proteins - metabolism; Doxorubicin - pharmacology; Drug Resistance, Multiple - physiology; Drug Resistance, Neoplasm - physiology; Etoposide - pharmacology; Heat-Shock Proteins - drug effects; Heat-Shock Proteins - metabolism; Humans; Mice; Paclitaxel - pharmacology; Piperidines - pharmacology; Pyridines - pharmacology; Tacrolimus Binding Proteins; Transfection; Tumor Cells, Cultured; Vincristine - pharmacology
• ISSN: 0959-4973
• DOI: 10.1097/00001813-199702000-00004

VX-710 or (S)-N[2-Oxo-2-(3,4,5-trimethoxyphenyl)acetyl]-piperidine-2-carboxylic acid 1,7-bis(3-pyridyl)-4-heptyl ester, a novel non-macrocyclic ligand of the FK506-binding protein FKBP12, was evaluated for its ability to reverse P-glycoprotein-mediated multidrug resistance in vitro. VX-710 at 0.5-5 microM restored sensitivity of a variety of multidrug resistant cells to the cytotoxic action of doxorubicin, vincristine, etoposide or paclitaxel, including drug-selected human myeloma and epithelial carcinoma cells, and human MDR1 cDNA-transfected mouse leukemia and fibroblast cells. Uptake experiments showed that VX-710 at 0.5-2.5 microM fully restored intracellular accumulation of [14C]doxorubicin in multidrug resistant cells, suggesting that VX-710 inhibits the drug efflux activity of P-glycoprotein. VX-710 effectively inhibited photoaffinity labeling of P-glycoprotein by [3H]azidopine or [125I]iodoaryl azidoprazosin with EC50 values of 0.75 and 0.55 microM. Moreover, P-glycoprotein was specifically labeled by a tritiated photoaffinity analog of VX-710 and unlabeled VX-710 inhibited analog binding with an EC50 of 0.75 microM. VX-710 also stimulated the vanadate-inhibitable P-glycoprotein ATPase activity 2- to 3-fold in a concentration-dependent manner with an apparent k(a) of 0.1 microM. These data indicate that a direct, high-affinity interaction of VX-710 with P-glycoprotein prevents efflux of cytotoxic drugs by the MDR1 gene product in multidrug resistant tumor cells.