Immune messenger chemicals in the body regulate the immune response by stimulating the production of growth factors or other chemical messengers to initiate or terminate an immune reaction. Interferons are used to treat several forms of cancer, although exactly how the drugs work has not been previously clear. Now, German scientists have found that a natural molecule present in the immune system called beta-interferon inhibits cancerous tumors’ attempts to connect to the blood circulatory system. Beta-interferon hinders the production of growth factors that support the formation of new blood vessels.
Researchers from the Helmholtz Center for Infection Research (HZI) in Braunschweig, Germany grew skin tumors in two groups of mice. Mice in the first group were not able to produce beta-interferon, while mice in the second group produced the immune substance in normal amounts. The researchers found that the tumors in the mice that could not produce interferon grew considerably larger and had more metastases.
The reason for these findings was that in the presence of beta-interferon, considerably fewer blood vessels developed within the tumors, a process called angiogenesis. Angiogenesis is critical for the growth and spread of most cancer types. Beta-interferon both inhibited the formation of vessel-producing growth factors and blocked blood vessel-producing cells from entering into the tumor. A negligible quantity of beta-interferon was sufficient to inhibit growth factors, thus arresting tumor growth.
“This mode of action on the part of beta-interferon had previously been unidentified”, said Siegfried Weiss, leader of the working group “Molecular Immunology” at HZI. The messenger substance actually plays a significant role in viral diseases and reactions to infections. “We now are attempting to understand the functioning of the network of tumor, immune cells and messenger substances in order to discover new target structures for cancer therapy”, said Weiss.