Dofequidar

Dofequidar (MS-209 free base) is an orally active quinoline compoundthat blocks P-glycoprotein (P-gp) and multidrug resistance-associated protein-1 (MDR-1). Dofequidar has highly potent reversing effect on multidrug-resistant tumor cells. Dofequidar competitively inhibits ABCB1/P-gp, ABCC1/MRP-1, blocks the efflux of chemotherapeutic agents, increases the drug concentration in cancer cells, and enhances the chemotherapeutic effect^[1][2]. In Vitro:Dofequidar in the in vitro proliferation and chemosensitivity assays of human small cell lung cancer SBC-3/ADM and SBC-3 cells completely reverses the multidrug resistance of SBC-3/ADM cells to Etoposide (VP-16) (HY-13629), Adriamycin, and Vincristine (HY-N0488) at concentrations of 3-10 μM, with little effect on the sensitivity of SBC-3 cells^[1].
Dofequidar in the P-gp expression analysis experiment of human small cell lung cancer SBC-3/ADM and SBC-3 cells does not change the P-gp expression of SBC-3 cells, while SBC-3/ADM cells express P-gp^[1].
Dofequidar at various concentrations reduces the proportion of side population (SP) cells in a dose-dependent manner in the SP cell sorting experiment of multiple cancer cell lines^[2].
Dofequidar increases the intracellular concentration of ABCC1⁄MDR-associated protein (MRP) in K562/BCRP cells in the intracellular drug accumulation experiment^[2]. In Vivo:Dofequidar (200 mg/kg; orally administered; starting from days 10 or 14 after tumor cell inoculation, 4 doses) in NK cell-depleted SCID mice inoculated with SBC-3/ADM or SBC-3 cells significantly inhibits the metastasis of SBC-3/ADM cells to multiple organs when combined with Etoposide (VP-16) (HY-13629) or Adriamycin^[1].
Dofequidar (200 mg/kg; orally administered; given 30 minutes before Irinotecan (CPT-11) (HY-16562) injection, and both are administered on days 0, 4, and 8; throughout the experiment) in nude mice inoculated with HeLa SP cells significantly reduces the tumor volume when combined with Irinotecan^[2].