PX-478 is a highly potent and selective Hypoxia-inducible Factor-1α (HIF-1α) inhibitor. It lowers HIF-1α protein levels and HIF-1 transactivation in hypoxia and in normoxia in a variety of cancer cell lines, but has a more pronounced effect on translation of proteins, such as HIF-1α in hypoxia. PX-478 also enhances the radiosensitivity of prostate carcinoma PC3 cells. Its inhibition is independent of the tumor suppressor genes VHL and p53, and may be related to derangements in glucose uptake and metabolism due to inhibition of glucose transporter-1 (Glut-1). PX-478 has excellent activity against established human tumor xenografts, inducing tumor regressions with prolonged growth delays which correlate positively with HIF-1 levels. In high-fat-diet mice, PX-478 causes reduced fibrosis and fewer inflammatory infiltrates in their adipose tissues. PX-478 had been in phase I clinical trials by for the treatment of lymphoma and solid tumors. However, this research has been discontinued.