Chemosensitizing micelles self-assembled from amphiphilic TPGS-indomethacin twin drug for significantly synergetic multidrug resistance reversal

Vitamin E d-alpha-tocopheryl poly(ethylene glycol) 1000 succinate (TPGS) and indomethacin (IDM) can reverse multidrug resistance (MDR) via inhibiting P-glycoprotein (P-gp) and multidrug resistance associated protein 1 (MRP1) respectively, but their drawbacks in physicochemical properties limit their clinical application. To overcome these defects and enhance MDR reversal, the amphiphilic TPGS-IDM twin drug was successfully synthesized via esterification, and could self-assemble into free and paclitaxel-loaded (PTX-loaded) micelles. The micelles exhibited lower CMC values (5.2 x 10(-5 )mg/mL), long-term stability in PBS (pH 7.4) for 7 days and SDS solution (5 mg/mL) for 3 days, and effective drug release at esterase/pH 5.0. Moreover, the micelles could down-regulate ATP levels and promote ROS production in MCF-7/ADR via the mitochondrial impairment, therefore achieving MDR reversal and cell apoptosis. Additionally, the PTX-loaded micelles could significantly inhibit the cell proliferation and promote apoptosis for MCF-7/ADR via the synergistic chemosensitizing effect of TPGS and IDM, and synergistic cytotoxic effect of TPGS and PTX. Thus, the chemosensitizing micelles self-assembled from amphiphilic TPGS-indomethacin twin drug have the great potentials for reversing MDR in clinical cancer therapy.