title: Cellular and biochemical characterization of VX-710 as a chemosensitizer: reversal of P-glycoprotein-mediated multidrug resistance in vitro.
abstract: 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.
authors.affiliation: Vertex Pharmaceuticals Inc., Cambridge, MA 02139-4242, USA.
authors.forename: U A
authors.initials: UA
authors.lastname: Germann
authors.forename: D
authors.initials: D
authors.lastname: Shlyakhter
authors.forename: V S
authors.initials: VS
authors.lastname: Mason
authors.forename: R E
authors.initials: RE
authors.lastname: Zelle
authors.forename: J P
authors.initials: JP
authors.lastname: Duffy
authors.forename: V
authors.initials: V
authors.lastname: Galullo
authors.forename: D M
authors.initials: DM
authors.lastname: Armistead
authors.forename: J O
authors.initials: JO
authors.lastname: Saunders
authors.forename: J
authors.initials: J
authors.lastname: Boger
authors.forename: M W
authors.initials: MW
authors.lastname: Harding
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000737:chemistry / Q000187:drug effects* / Q000235:genetics / Q000502:physiology*; D000251:Adenosine Triphosphatases / Q000187:drug effects / Q000378:metabolism; D000345:Affinity Labels; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002352:Carrier Proteins / Q000187:drug effects / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000187:drug effects / Q000378:metabolism; D004317:Doxorubicin / Q000494:pharmacology; D018432:Drug Resistance, Multiple / Q000502:physiology*; D019008:Drug Resistance, Neoplasm / Q000502:physiology; D005047:Etoposide / Q000494:pharmacology; D006360:Heat-Shock Proteins / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D051379:Mice; D017239:Paclitaxel / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology*; D011725:Pyridines / Q000494:pharmacology*; D022021:Tacrolimus Binding Proteins; D014162:Transfection; D014407:Tumor Cells, Cultured; D014750:Vincristine / Q000494:pharmacology
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000345:Affinity Labels; D000970:Antineoplastic Agents; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D006360:Heat-Shock Proteins; D010880:Piperidines; D011725:Pyridines; C106077:biricodar; D014750:Vincristine; D005047:Etoposide; D004317:Doxorubicin; D000251:Adenosine Triphosphatases; D022021:Tacrolimus Binding Proteins; D017239:Paclitaxel