BCRP

BCRP inhibitors block breast cancer resistance protein (BCRP), a drug efflux pump in cell membranes. BCRP is ATP-binding cassette (ABC) subfamily G member 2 (ABCG2), a half transporter that works as a homodimer. It was first cloned from drug-selected breast cancer cells, where it conferred resistance to mitoxantrone and anthracyclines. In normal tissues it lines the intestine, bile canaliculi, placenta and blood-brain barrier and limits the entry of many xenobiotics. Inhibitors are used to study drug transport, oral absorption and multidrug resistance in cell and animal models. Ko-143, an analog of the fungal toxin fumitremorgin C, inhibits BCRP selectively. Elacridar blocks both BCRP and P-glycoprotein, listed under P-gp, while YHO-13177 and ML230 are further BCRP inhibitors.