BET bromodomain inhibitor 1 is an orally active, selective inhibitor of bromodomain and extra-terminal (BET) proteins. It specifically inhibits BRD4 with an IC50 of 2.6 nM. Additionally, BET bromodomain inhibitor 1 demonstrates high affinities towards BRD2(2), BRD3(2), BRD4(1), BRD4(2), and BRDT(2) with Kd values of 1.3 nM, 1.0 nM, 3.0 nM, 1.6 nM, and 2.1 nM, respectively. This compound exhibits anti-cancer activity.

BRD3(2):1.0 nM (Kd), BRD4(2):1.6 nM (Kd), BRD2(2):1.3 nM (Kd), BRDT2:2.1 nM (Kd), BRD4(1):3.0 nM (Kd), BRD4:2.6 nM (IC50)

BET bromodomain inhibitor 1 (compound 38; 31.25-125 nM; 24 hours) leads to more pronounced G1-phase cell cycle arrest[1]. BET bromodomain inhibitor 1 (31.25-500 nM; 6 or 24 hours) is highly effective in inducing dose-dependent inhibition on c-Myc expression and upregulation of p21 levels[1]. BET bromodomain inhibitor 1 (31.25-125 nM; 6 hours) robustly reduces the expressions of c-Myc, BCL-2, and CDK6[1]. BET bromodomain inhibitor 1 does not inhibit five cytochrome P450 enzymes (IC 50 >20 μM)[1]. BET bromodomain inhibitor 1 demonstrates an excellent selectivity for the BET bromodomain family over other bromodomains, with an ～1500-fold selectivity for BRD4(1) over EP300 (IC 50 =3857 nM)[1]. BET bromodomain inhibitor 1 strongly inhibited the growth of acute myeloid leukemia cell line MV4-11, acute leukemia cell lines Kasumi-1 and RS-4-11, and multiple myeloma cancer cell line MM1.S cells with IC 50 values of 2.4, 4.8, 17.6 and 15.1 nM, respectively[1]. Cell Cycle Analysis[1]Cell Line: MV-4-11 cells Concentration: 31.25, 62.5, 125 nM Incubation Time: 24 hours Result: Led to more pronounced G1-phase cell cycle arrest. Western Blot Analysis[1]Cell Line: MV-4-11 cells Concentration: 31.25, 62.5, 125, 250, 500 nM Incubation Time: 6 or 24 hours Result: Induced dose-dependent inhibition on c-Myc expression and upregulation of p21 levels. RT-PCR[1]Cell Line: MV-4-11 cells Concentration: 31.25, 62.5, 125 nM Incubation Time: 6 hours Result: Robustly reduced the expressions of c-Myc, BCL-2, and CDK6.

BET bromodomain inhibitor 1 (compound 38; 6.25, 12.5 mg/kg; PO; daily ; for 28 days) exhibits stronger antitumor activities and completely inhibits the growth of tumor with a tumor growth inhibition (TGI) of 99.7% at 12.5 mg/kg[1]. BET bromodomain inhibitor 1 (1 mg/kg; IV) has a T 1/2 of 1.3 and 0.9 hours, a CL of 21.5 and 15.3 mL/min?kg, and a V ss of 1464 and 782 mL/kg for rats and mouse, respectively[1]. BET bromodomain inhibitor 1 (3 mg/kg; PO) has a T 1/2 of 3.6 hours, a C max of 159 ng/mL and an AUC of 884 ng?h/mL for rats[1]. BET bromodomain inhibitor 1 (1.3 mg/kg; PO) has a T 1/2 of 1.3 hours, a C max of 399 ng/mL and an AUC of 1710 ng?h/mL for mouse[1]. Animal Model: An MV4-11 mouse xenograft model[1]Dosage: 6.25, 12.5 mg/kg Administration: PO; daily ; for 28 days Result: Exhibited stronger antitumor activities and completely inhibited the growth of tumor with a tumor growth inhibition (TGI) of 99.7% at 12.5 mg/kg. Animal Model: Male SD rats[1]Dosage: 1 mg/kg (Pharmacokinetic Analysis) Administration: IV Result: Had a T 1/2 of 1.3 hours, a CL of 21.5 mL/min?kg, and a V ss of 1464 mL/kg.