PT2385

PT2385 blocks HIF-2α dimerization with the HIF1α/2α transcriptional dimerization partner ARNT/HIF1β. PT2385 inhibits the expression of HIF2α-dependent genes, including VEGF-A, PAI-1, and cyclin D1 in ccRCC cell lines and tumor xenografts. PT2385 has no effect on the proliferation or viability of 786-O and A498 cells in culture at concentration as high as 10 μmol/L. Treatment of 786-O cells with PT2385 significantly reduces the levels of mRNA for CCND1, VEGF-A, GLUT1, and PAI-1 in a concentration-dependent manner. Treatment of Hep3B cells with PT2385 reduces hypoxia-induced expression of erythropoietin (EPO) and PAI-1, both known HIF2α target genes^[2].

About 7500 of 786-O cells in 180 μL of growth medium are seeded into each well of a 96 well plate with white clear bottom on the first day. Four hours later, serial dilutions of 10x compound stocks are made in growth medium from 500x DMSO stocks, and 20 μL of those 10x stocks are added to each well to make final concentrations as follows (μM): 20, 6.67, 2.22, 0.74, 0.25, 0.082, 0.027, 0.009, 0.003, 0.001, and 0. Each concentration has duplicated wells. About 20 hours later, medium is removed by suction and each well is supplied with 180 μL of growth medium. About 20 μl freshly-made 10x compound stocks are added to each well. About 24 hours later, cell culture medium is removed for the determination of VEGFA concentration using an ELISA kit.

PT2385 exhibits good mouse oral bioavailability (110%) and low to medium in vivo clearance. In mice administrated via intravenous injection, the t_1/2 of PT2385 is 3.3 h. In rat pharmacokinetics studies, the oral bioavailability (F) when dosed at 10 mg/kg is 40% and the t_1/2 is 3.3 h. In dogs, the oral bioavailability (F) is 87% and the t_1/2 is 11 h^[1]. Treatment of tumor-bearing mice with PT2385 causes dramatic tumor regressions (clear cell renal cell carcinomas). PT2385 exhibits no adverse effect on cardiovascular performance^[2].