Estrogen Receptor β2 Induces Hypoxia Signature of Gene Expression by Stabilizing HIF-1α in Prostate Cancer

The estrogen receptor (ER) beta variant ER beta 2 is expressed in aggressive castration-resistant prostate cancer and has been shown to correlate with decreased overall survival. Genome-wide expression analysis after ER beta 2 expression in prostate cancer cells revealed that hypoxia was an overrepresented theme. Here we show that ER beta 2 interacts with and stabilizes HIF-1 alpha protein in normoxia, thereby inducing a hypoxic gene expression signature. HIF-1 alpha is known to stimulate metastasis by increasing expression of Twist1 and increasing vascularization by directly activating VEGF expression. We found that ER beta 2 interacts with HIF-1 alpha and piggybacks to the HIF-1 alpha response element present on the proximal Twist1 and VEGF promoters. These findings suggest that at least part of the oncogenic effects of ER beta 2 is mediated by HIF-1 alpha and that targeting of this ER beta 2 -HIF-1 alpha interaction may be a strategy to treat prostate cancer.