P-glycoprotein (P-gp) is one of several ABC transporters that can pump drugs out of tumor cells and thereby render chemotherapy ineffective. Overexpression of P-gp can give rise to multidrug resistance, making cancers quite difficult to treat. Several inhibitors of P-gp have been described, but none has entered the clinic, mainly because of poor efficacy or adverse reactions.

One of the well-established mechanisms of multidrug resistance (MDR) to chemotherapy in cancer patients is ATP binding cassette (ABC) transporter overexpression in cancer cell membrane, and as the most extensively characterized ABC transporter, P-glycoprotein (P-gp) is considered a potential target to overcome MDR. In a recent publication, researchers from Xuzhou Medical University detailed the discovery of novel P-gp inhibitors as candidates to overcome MDR to chemotherapy.