Biochem/physiol Actions

PSB-603 is an adenosine receptor A2b antagonist (IC50 = 1.13 nM against 10 µM A2bR agonist NECA-induced calcium response in Jurkat T cells in the presence of 200 nM A2aR antagonist MSX-2) that targets A2bR with high affinity (KD = 0.403 nM/human, 0.457 nM/rat, 4.09 nM/mouse A2bR; Ki against 0.3 nM [3H]PSB-603 = 0.553 nM/human, 0.355 nM/rat, 0.265 nM/mouse A2bR) and selectivity, exhibiting little affinity toward A1, A2a, or A3 adenosine receptors by competition binding assay (Ki >10 µM against 0.4 nM [3H]DPCPX for human/rat A1R, 1 nM [3H]MSX-2 for human/mouse/rat A2aR, 10 nM [3H]NECA for human/mouse/rat A3R) with the exception of mouse A1R (Ki = 42.2 nM against 0.4 nM [3H]DPCPX).

PSB-603 is known to modify cellular metabolism and enhance cellular sensitivity for chemotherapy. Thus, PSB-603 is recognized to possess anticancer action, which has been studied in colorectal cancer.