Multispecificity of drug transporters: probing inhibitor selectivity for the human drug efflux transporters ABCB1 and ABCG2.

Multidrug resistance transporters P-glycoprotein/ABCB1 and ABCG2 limit the effect of a large number of cytostatic and cytotoxic drugs by energy-dependent efflux. In experimental models, pump inhibitors reestablish sensitivity towards these drugs. Both transporters demonstrate remarkably broad and partly overlapping substrate specificity.