Hepatocyte nuclear factor-4 (HNF-4α) is not involved in hypoxia induced Erythropoietin regulation in human neuroblastoma cell lines

Oxygen dependent Erythropoietin (EPO) production is regulated by hypoxia inducible factor-1 (HIF-1) which consists of the O2-labile α- and the constitutive β-subunit. In human hepatoma cells (HepG2) HNF-4α enhances hypoxia-induced EPO expression. Herein, we investigated EPO gene regulation in human neuroblastoma (NB) cell lines. Methods: EPO production in SH-SY5Y, Kelly and HepG2 cells was measured by real time PCR and EPO elisa. Intracellular distribution of HIF-1α, HIF-1β and HNF-4α was studied by Western blot and immunohistochemistry. Cells were transiently transfected with HIF-1-driven luciferase and a dominant negative (dn) HNF-4 plasmid. Results: Hypoxia induced EPO gene expression in NB cells was maximal at