Modulation of ABCG2 ATPase activity by A3 adenosine receptor ligands. Results for four representative ligands, the potent A3 agonist 5 (A), triazole-extended 6-benzylamino derivative 17 (B), adenine (A3 antagonist) derivative 37c (C), and (N)-methanocarba-7-deazaadenosine 5’-ester derivative 60 (D) are shown. Each experiment was performed at least three times in duplicate. The EC50 and IC50 values were calculated using GraphPad Prism (GraphPad Software, San Diego, CA, USA).