Scientists have designed a therapeutic protein which has the ability to target the receptors which are commonly found on the surface of unhealthy cells, linked to the progression of a number of diseases, which include cancer. The discovery of the new protein, as well as the particular way in which it binds to abnormal cells, could probably lead to new, as well as more effective treatments in the future.
The protein which is in question is called ProAgio is developed from a human protein. It targets transmembrane receptor on the surface of cells, which is called an integrin. It enables cells to interact with one another. Integrin αVβ₃ is actually the receptor that ProAgio seeks. The integrin αVβ₃ is a molecule which scientists have long looked at as a focus for medicines. It usually goes hand – in – hand with abnormal cells which can turn cancerous.
The molecular biologist Zhi-Ren Liu, from Georgia State University, said:
“In normal tissue, this integrin pair, αVβ₃, is actually not expressed in high levels. In most of the cases, it is actually associated with a number of different pathological conditions. Because of that, it constitutes a very good target for multiple disease treatment. “
Integrin αVβ₃ is actually not unique to unhealthy cells. It is usually expressed in the cells of new blood vessels, macrophages (immune cells) and bone cells. But, it is not usually at work in metastasizing cancer cells, which spread to some other parts of the body, which is why it interests drug developers.
Scientists have developed a treatment which hones in on a αVβ₃ previously, by a process which is called ligand binding, docking with the integrin by a form of chemical bonding. But, until now, these techniques have not been very successful, so Liu, together with his team, adopted a different approach.
“We took a unique angle. We designed a protein which binds to a different site [of αVβ₃, which is called the βA-groove]. Once it binds to the site, it directly triggers cell death. We will have the ability to kill pathological cells. After that, we will have the ability to kill the disease as well.”
By a mechanism which is still not fully understood by scientists, ProAgio recruits an enzyme. It is called caspase 8 that pays a huge role in apoptosis – programmed cell death. ProAgio basically enlists caspase 8 and also induces cells which stand a good chance of becoming cancerous to self-destruct, by targeting cells bearing the αVβ₃ receptors.
In the testing which was made on mice with tumors, the researchers found that ProAgio’s impact strongly inhibited tumor growth, as well as reduce tumor blood vessels, while existing blood vessels were not affected. Toxicity tests have shown that the treatment was not toxic to healthy mouse tissue.
ProAgio has so far only been tested on animals. Therefore, it is actually a long way to go before we all know whether these beneficial effects extend safely to people. But, it is still a very promising development, and we cannot wait to see where this research leads.