NP-1250, an ABCG2 inhibitor, induces apoptotic cell death in mitoxantrone-resistant breast carcinoma MCF7 cells via a caspase-independent pathway

: Chemoresistance is one of the main obstacles to successful cancer therapy and is frequently associated with multidrug resistance (MDR). One of the most studied mechanisms of MDR is the high expression of ATP-binding cassette (ABC) transporters. Here, we demonstrated that NP-1250, an ABCG2 inhibitor, induced apoptotic cell death in ABCG2-overexpressing multidrug-resistant MCF7/mitoxantrone-resistant (MX) human breast carcinoma cells via a caspase-independent pathway. Incubation of MCF7/MX cells with NP-1250 significantly reduced cell viability, while NP-1250 had little effect on the viability of drug-sensitive MCF7/wild-type cells. Although the target molecules of NP-1250 in cell death remain unknown, investigation of NP-1250 will aid in the elucidation of the molecular mechanism of drug resistance and NP-1250 may become a new therapy for MDR cancers.