Protein kinase C-delta regulates the stability of hypoxia-inducible factor-1 alpha under hypoxia.

Hypoxia is a state of deficiency of available oxygen in the blood and tissues, and it occurs during several pathophysiological processes, including tumorigenesis. Under hypoxia, hypoxia-inducible factor-1 (HIF-1) plays an essential role in cellular oxygen homeostasis. In the present article protein kinase C-delta (PKC-delta) is activated by hypoxia, increases the protein stability and transcriptional activity of HIF-1alpha in human cervical adenocarcinoma cells. Moreover, the knockdown of PKC-delta inhibited vascular endothelial growth factor expression and angiogenic activity under hypoxia. These effects were completely reversed by PKC-delta overexpression following the knockdown of PKC-delta. Collectively, these findings demonstrate the role of PKC-delta as a new regulator of hypoxia-induced angiogenesis.