BIM-26226

BIM-26226 is a selective gastrin-releasing peptide receptor (GRPR) (IC₅₀ = 6 nM) and bombesin receptor (BN receptor) antagonist. BIM-26226 antagonizes BN- or GRP-stimulated amylase release with IC₅₀ values of 0.3 nM and 0.2 nM, respectively. BIM-26226 is specific for the GRP-preferring BN receptor subtype with no interference with GRP receptor system. BIM-26226 can induce the synthesis of somatostatin receptor but has no significant effect on tumor growth^[1][2][3][4]. IC50 & Target:bombesin receptor^[1] In Vitro:BIM-26226 (0.1 nM-1 μM, 24 h) significantly decreased [³H]thymidine incorporation in primary cultured pancreatic tumour cells^[1].
BIM-26226 is specific for the GRP-preferring BN receptor subtype and is not able to inhibit binding of radio-labeled CCK-33, gastrin-17 or VIP in AR4-2J cells^[2].
BIM-26226 (0.1 μM) is able to block the bombesin-induced increase of Ca²⁺ but fails to block the growth-stimulatory effect of bombesin^[3].
In Vivo:BIM-26226 (30 and 100 μg/kg, s.c., 3 times daily for 14 consecutive days) inhibits the GRP-stimulated growth of a pancreatic cancer transplanted in the rat but, alone, has little influence on tumor growth ^[1].
BIM-26226 (100 μg/kg, s.c., once daily for 6 weeks) induces the synthesis of somatostatin receptor but has no effect on tumor growth in colon cancer rat model^[3].