Control of HIF-1alpha expression by eIF2 alpha phosphorylation-mediated translational repression.

ABSTRACT: Hypoxia inducible factor 1alpha (HIF-1alpha) plays a central role in regulating tumor angiogenesis via its effects on vascular endothelial growth factor (VEGF) transcription, and its expression is regulated through proteasome-mediated degradation. Paradoxically, previous studies have shown that proteasome inhibitors (PI) block tumor angiogensis by reducing VEGF expression, but the mechanisms have not been identified. Here, we report that PIs down-regulated HIF-1alpha protein levels and blocked HIF-1alpha transcriptional activity in human prostate cancer cells. PIs induced phosphorylation of the translation initiation factor 2alpha (eIF2alpha), which caused general translational repression to inhibit HIF-1alpha expression. Furthermore, PIs induced HIF-1alpha accumulation in LNCaP-Pro5 cells

SUBMITTER: Zhu K 

PROVIDER: S-EPMC4188393 | biostudies-literature | 2009 Mar

REPOSITORIES: biostudies-literature