Angiogenesis is a term that describes the growth of a new network of blood vessels. According to the latest research, angiogenesis is an extremely crucial process required for a cancer to develop and spread, or metastasize. Therefore, anti-angiogenesis is a term that describes attempts to inhibit that development.
Tumor angiogenesis
When angiogenesis occurs in conjunction with a cancerous tumor, it occurs because the cancer cells have sent signals to the surrounding tissue (known as its microenvironment) to activate certain genes that will make the proteins necessary for those blood vessels to develop.
Thus angiogenesis—the creation of new blood vessels that can supply a growing tumor with the necessary nutrients while carrying away its waste products—can be seen as a very important aspect of tumor proliferation.
There have been several proteins and other molecules that have been identified as being particularly angiogenic, with at least two proteins having identified as being among the more important ones:
-- Vascular endothelial growth factor (VEGF)
-- Basic fibroblast growth factor (bFGF).
Both VEGF and bFGF are produced by both normal cells as well as cancerous cells.
Anti-angiogenesis
Since angiogenesis has been deemed crucial to the survival and development of a tumor, and because at least two proteins have been identified so closely with the process, researchers have targeted angiogenesis as a potential target for anti-cancer treatments. These are known as angiogenesis inhibitors, and their purpose is clear: prevent the development of those vital blood vessels in tumors.
How they go about this—meaning what mechanism of action they apply—differs from approach to approach. For instance, some directly inhibit proliferation of the endothelial cells while others inhibit the angiogenesis signaling cascade. These treatments include:
Thalidomide
Bevacizumab (Avastin), an FDA approved, anti-VEGF monoclonal antibody
Interferon-alpha, an FDA approved bFGF and VEGF inhibitor
Combretastatin A4
Anti-angiogenesis is an emerging field of anti-cancer research that is largely in its infancy. While it presents great potential in the treatment of cancer, and while some drugs have been approved for this treatment, developments in this field should be met with a degree of skepticism.
Sources
National Cancer Institute, Understanding Cancer Series: Angiogenesis
