The hypoxia-inducible factors HIF-1 alpha and HIF-2 alpha are two closely related transcription factors, which promote the expression of proteins involved in the cellular response to hypoxia, or low cellular oxygen. HIF antibodies are widely used to study hypoxia in relation to human disease.
Abnormal expression of hypoxia inducible factors is symptomatic of a number of human diseases, including cancer. Solid tumours are often hypoxic and necrotic, owing to poor vascularity. The tumour cells can adapt to this by altering the phenotype of HIF proteins. Experiments using products from our antibody database have revealed HIF-2 alpha plays a significant role in the development of certain tumours.
In 2006, Ioachim et al studied expression of HIF-1alpha and HIF-2alpha in bladder tumour cells, reporting high levels of HIF-2a in almost 62% of cases. Immunohistochemistry assays with relevant antibodies confirmed correlation with fibronectin and thymidine phosphorylase expression. Fibronectin is a potent wound healer also involved in cell motility, adhesion and cell shape, while thymidine phosphorylase stimulates growth in a number of endothelial cell types. Both have been implicated in the development of various cancers, including lung, breast and bladder cancer.
HIF-2a expression was also reported in paraffin-embedded hepatocellular carcinoma (HCC) sections, at levels which correlated with tumour size, portal vein invasion, capsular infiltration and necrosis, indicating HIF-2a had a possible metastatic role. A parallel VEGF antibody study suggested HIF-2alpha upregulation was linked to tumour angiogenesis i.e. formation of new blood vessels, a key element of metastasis.
Antibody studies in foetal cells have reported HIF-2a expression in both hypoxic and normoxic neuroblastomas. HIF-2a is also found in normal cells and may be involved in SNS (sympathetic nervous system) development.Placental hypoxia is linked to pre-eclampsia in pregnant women. In 2001, Rajakumar et al studied the expression of HIF proteins in preeclamptic human placental tissue, and reported selective overexpression of HIF-2a. This was the first time abnormal expression had been reported in a human disease other than cancer.Our antibody catalog at Novus Biologicals has an extensive hypoxia antibody database, with almost 20 HIF-2 alpha antibodies alone.