Component in Cotton Could Halt Prostate Cancer Development

A component found in cotton is undergoing early phase clinical trials in the treatment of prostate cancer.

Gossypol is a natural component that is a byproduct found in a cotton plant and could potentially rid the body of abnormal cancerous cells, according to a recent paper published in Molecular Oncology.

However, destroying cancer causing genes is an uphill battle for researchers because these genes are both miniscule and complex, but it is a priority for helping patients.

Researcher Liang Xu, PhD, has been studying the protein musashi, which is overexpressed in many different types of cancers and even more specifically in colorectal cancer. Researchers are also examining the potential use of natural therapy in order to block musashi.

It’s believed that mushashi is the cause of abnormal cell division and the growth of tumors. The protein is also associated with cancer stem cells, which can endlessly divide into cancerous cells throughout the body. These are believed to cause recurring cancers that appear later on.

Kristi Neufeld, PhD, who has partnered up with Dr. Xu and his team, has being looking at how a tumor suppressor protein called APC interacts with musashi. She discovered that when APC and musashi interact together they create a double negative, causing APC to help prevent musashi from being overexpressed.

"APC not only inhibits musashi, but musashi inhibits APC, so these 2 proteins seem to have this double negative where they're trying to keep the other one from functioning," Dr. Neufeld said. "So you can think of musashi as potentially being oncogenic -- too much of it will promote tumors because it's overpowering proteins like APC and triggering those pathways that promote uncontrolled cell growth."

Finding an inhibitor of musashi is difficult because it interacts with RNA-binding proteins that require specific drugs for inactivation.

"A lot of cancers, involve protein and protein interaction, which is like shaking hands with someone," Dr. Xu said. "This is a very broad interaction, especially when you want to find something small that will block the two hands from shaking, so to speak. Musashi, however, is an RNA-binding protein, which is like a hand trying to grab a string. A much smaller target for which it is much more difficult to design a drug."

During the experiments, Dr. Xu looked at the measurement of how much musashi was functioning or present, by using fluorescence polarization competition assay. He found that gossypol had a strong binding with musashi.

The results of the study showed that gossypol directly interacts with the RNA-binding protein of musashi. When gossypol binds to musashi, it stops cells from dividing and induces abnormal cell death in colon cancer cells, which helps prevent cancer from spreading.

This is of great importance in developing a new cancer drug because musashi is being directly targeted. A targeted therapy could potentially rid the body of the abnormal cells without causing damage to healthy cells.

"This is the first drug that appears to target a RNA-binding protein in a successful way," Dr. Xu said. "If we can create a drug that people can take to block this protein and stop cancer from starting or recurring, it would be an ideal situation for patients."