BAY 87-2243

BAY 87-2243 is a potent and selective hypoxia-inducible factor-1 (HIF-1) inhibitor. Phase 1. (In Vitro) :BAY 87-2243 inhibits luciferase activity with a calculated IC50 value of ~0.7 nM. Hypoxic induction of the HIF target gene CA9 on protein level in HCT116luc cells is inhibited by BAY 87-2243 with an IC50 value of ~2 nM. BAY 87-2243 inhibits mitochondrial oxygen consumption measured by using the oxygen sensitive fluorescence dye LUX-MitoXpress with an IC50 value of ~10 nM. BAY-87-2243 inhibits nuclear HIF-1α protein expression. Administration of BAY-87-2243 for about 18 days significantly reduces HIF-1α protein expression as well as pimonidazole hypoxic fraction (pHF) (mean 2.4% (BAY-87-2243) vs. 17.6% (carrier), p<0.0001), and necrotic fraction (NF) (mean 9% vs. 35.6%, p=0.0002), whereas relative vascular area (RVA) and perfused vessels (PF) remained unchanged. (In Vivo) :Nude mice are inoculated with H460 cells subcutaneously and after tumors have been established, animals are treated with BAY 87-2243 (0.5, 1, 2, and 4 mg/kg) for 3 weeks by daily oral gavage. BAY 87-2243 reduced tumor weight dose dependently in line with a dose-dependent reduction of the mRNA expression levels of the HIF-1 target genes CA9, ANGPTL4, and EGLN3, whereas the mRNA expression levels of hypoxia-insensitive EGLN2 gene and of HIF-1α itself are not affected by compound treatment in vivo.