Multi-drug resistance (MDR) is one of the leading reasons that cause the failures of cancer treatment. Novel agents that may reverse MDR and neutralize drug-resistant cancer cells are highly desirable for clinical practice. The targeting of cellular redox homeostasis and/or mitochondria-mediated energy metabolism are promising strategies for the suppression of drug-resistant cancer cells. Based on the structure of mono-gold(I) complex auranofin (AF), a drug candidate under clinical trials for cancer, we synthesized a new dual-gold(I) complex QB1561 and tested if it can inhibit drug-resistant cancer cells overexpressing ATP-binding cassette (ABC) transporters. We also investigated if QB1561 could inhibit thioredoxin reductase (TrxR), a well-known target of AF and other gold complexes, and assessed its impact on mitochondrial respiration.
