Finally, we found that overexpression of hClock enhanced the expression of angiogenesis-related genes such as HIF-1α, ARNT and VEGF, and promoted epithelial-mesenchymal (-like) transition (EMT) in CRC cells, both of which are considered to be critical for tumor progression.
In a tumor xenograft model, we consistently found that loss of p53 promotes VEGF production, neovascularization, and tumor progression via accumulation of HIF-1β protein.
Hypoxia-inducible factor 1 (HIF-1), a pivotal transcription factor composed of HIF-1alpha and HIF-1beta subunits, plays a major role in tumor progression by activating a number of genes critically involved in adaptation to hypoxia.