9-β-D-arabinofuranosyl-2-fluoroadenine inhibits expression of vascular endothelial growth factor through hypoxia-inducible factor-1 in human ovarian cancer cells

Ovarian cancer is the leading cause of death from gynecological malignancy and has the worst prognosis of all gynecological cancers. Vascular endothelial growth factor ( VEGF) plays an important role in ovarian cancer development. 9-beta-D-Arabinofuranosyl-2-fluoroadenine (Fara-A), a nucleotide analog, is frequently used in treating certain types of cancer. However, the effectiveness of Fara-A on ovarian cancer cells is unknown. In this study, we found that Fara-A inhibited VEGF expression in human ovarian cancer cells. Fara-A inhibited VEGF transcriptional activation through hypoxia-inducible factor 1 (HIF-1). HIF-1 is composed of HIF-1alpha and -1beta subunits. Fara-A inhibited expression of HIF-1alpha but not HIF-1beta. Overexpression of HIF-1alpha reversed Fara-A-inhibited VEGF transcriptional activation. Our results demonstrated that Fara-A inhibited VEGF transcriptional activation through HIF-1alpha expression. Fara-A partly inhibited HIF-1alpha mRNA levels. Fara-A blocked the activation of AKT but not of ERK1/2. Overexpression of AKT reversed the Fara-A-inhibited VEGF transcriptional activation, suggesting that Fara-A inhibits VEGF expression via phosphatidylinositol 3-kinase/AKT signaling. These results demonstrate a new function of Fara-A in inhibiting VEGF and HIF-1alpha expression and identify a potential molecular mechanism of the regulation.