Figure 7.
Differential Functions of HIF-1 and HIF-2 during Metastasis Depend on Differential NO Synthesis
As shown, HIF-1 and HIF-2 response in endothelial cells gives rise to differing levels of NO production following hypoxic induction of the factors: in this case, through hypoxic stress caused by tumor cell-induced blockage of a capillary. This, in turn, results in differing levels of metastatic success when one or the other HIF is genetically deleted from the endothelial cell. A remaining and important question is how hypoxic stress can cause differing levels of induction of the two HIF factors.