HIF-2α-IN-4 is a potent inhibitor of hypoxia inducible factor-2α (HIF-2α) translation, with an IC50 of 5 μM. HIF-2α-IN-4 decreases both constitutive and hypoxia-induced HIF-2α protein expression. HIF-2α-IN-4 links its 5'UTR iron-responsive element to oxygen sensing.