Effect of four novel inhibitors on HIF-1 signaling pathway. Inhibition of HIF-1 mediated β-lactamase activity in HRE-bla ME-180 cells by various concentrations of NCGC00043898, NCGC00044926, NCGC00049606 and NCGC00056044 in the presence of 1% oxygen (A) and 60 μM CoCl2 (B). The data are displayed as the percentage of control. Representative values are from a single experiment performed in duplicate. Data are expressed as mean ± SD.