Finding natural nutritional supplements with healthy benefits is nothing new. But researchers are discovering many supplements can help in more ways than one.
Take grape seed extract, for example. This popular supplement has been shown to lower breast cancer risk in some patients. Now research from City of Hope shows how it might fight cancer: by blocking a protein that helps tumors get their blood supply.
|Wei Wen, right, and Jianming Lu are examining how grape seed extract might help starve tumors. (Photo by Darrin S. Joy)|
Researchers in City of Hope’s divisions of Tumor Cell Biology and Molecular Medicine found in their study that grape seed extract blocks the production of an important protein in the body called VEGF (short for vascular endothelial growth factor).
VEGF coaxes new blood vessels to grow, a process called angiogenesis. VEGF is often highly active in tumors, which need new blood vessels to bring them nourishment.
Wei Wen, Ph.D., assistant professor of molecular medicine and senior author on the study, searches for compounds that might be able to block VEGF.
“I’m particularly interested in natural products that can block angiogenesis,” she said.
Compounds that block angiogenesis have proven effective against cancers such as colorectal and kidney tumors.
Grape seed extract is a popular dietary supplement. Previous research has shown the extract can slow or prevent the growth of certain tumors, and recent studies suggest it can block blood vessel growth. City of Hope research has shown it can reduce levels of estrogen, a major player in many breast cancers.
When Wen tested grape seed extract, she found it successfully could block production of VEGF. She and her team then sought to understand exactly how it worked.
They found grape seed extract actually lowers the level of another protein that cells need to make VEGF. That protein, called HIF-1α (short for hypoxia-inducible factor 1α) becomes more active when oxygen levels are low, such as when oxygen-rich blood is in short supply.
When oxygen is scarce, HIF-1α bumps up VEGF levels to make more blood vessels. In tumors, this process is amplified to feed the cancer’s ravenous need for oxygen and other nutrients carried by blood.
Blocking HIF-1α, and in turn VEGF, would choke off the tumor’s blood supply, starving it.
In a 2008 study in Cancer Prevention Research, the researchers also found that grape seed extract can block VEGF signaling through another mechanism as well, potentially making the extract doubly potent.
The researchers hope to build on their findings and eventually study grape seed extract’s anticancer effects in combination with other therapies.