How to Modulate Tumor Hypoxia for Preclinical In Vivo Imaging Research

Figure 1

The HIF-1 pathway. (a) Under hypoxic conditions, HIF-1α stabilizes, and its transcriptional activity is regulated by heterodimerization with the constitutively expressed HIF-1β and binding to the hypoxia-response elements in the promoters of genes that regulate a variety of biological processes. These include genes involved in tumor survival, progression, and proliferation, such as VEGF. (b) Under normoxic conditions, the HIF-1α subunit is rapidly degraded by the proteasome after hydroxylation and ubiquitination.