The MDR1 mRNA level of K562/A02 cells with nanoparticles (5.0 × 10−7 M Nano-Fe3O4 or 2.0 × 10−8 M Nano-Au) in the absence or presence of DNR (10 mg/L) Lane:1, marker; 2, K562 (negative control); 3, K562/A02 (positive control); 4, Nano-Fe3O4; 5, Nano-Au; 6, DNR with Nano-Fe3O4; 7, DNR with Nano-Au.