Dietary Components May Help Colon Cancer by Targeting Inflammation

Division Of Cancer Prevention

Inflammation sits at the intersection of modern cancer research and traditional medicine. Many of the phytochemicals found in plants used in Asian medicines have demonstrated anti-inflammatory, anti-carcinogenic effects in modern laboratories, which suggests why flavonols and certain other common plant compounds recur in the catalogs and pharmacopeias of traditional medicine across cultures and down through time.

Angela Murphy, Ph.D., research assistant professor in the Division of Applied Physiology at the University of South Carolina is trying to look more closely at how inflammation may increase the risk of colorectal cancer (CRC), and how foods or naturally occurring supplements with bioactive components linked to beneficial health effects might reduce that risk.

Dietary flavonols occur in various fruits and vegetables, but one of them quercetin – commonly found in apples, blueberries, grapes, and some vegetables – has only recently begin to draw the attention of researchers, said Dr. Murphy. “Quercetin is an exciting target to study because of its role in inflammation. We have shown some significant anti-inflammatory activity in a mouse model of CRC.”

NCI funding* is helping Dr. Murphy and colleagues look deeper into the molecular details of inflammation and CRC. “We and many others have also found significant anti-inflammatory activity with curcumin,” another herbal extract from the plant used to make curry in Indian dishes, she added. The researchers will explore whether these two different compounds might have an additive or even synergistic impact on the inflammatory tumor microenvironment found in CRC.

The molecular and chemical process of inflammation at tumor sites is complex, but a central actor is the macrophage, explained Dr. Murphy. Tumor-associated macrophages are mature cells that develop from monocytes, a precursor cell type circulating in the blood. A signal known as monocyte chemo-attractant protein recruits these cells to a site in the body where inflammation has or could begin to develop, a process that can cause precancerous polyps to form in the colon, she said. Once there, macrophages fuel inflammation, enhancing the survival, growth and motility of cancer cells.

“We know that macrophage-induced inflammation plays an important role in the initiation and progression of CRC,” Dr. Murphy noted, “and it may also be responsible for the fatigue, lack of appetite and body wasting that so compromises the quality of life in these patients. This is a cancer where nutrition and diet play an important role in causing many cases.” Their work with curcumin and quercetin is designed to use diet to possibly prevent some of these cancers.

Dr. Murphy said there is already evidence that both curcumin and quercetin work independently against inflammation, however, looking at their impact in dietary combination is a new research approach. “They might be targeting different pathways and stages of the inflammatory process,” she said. The researchers will test to see if using the compounds together provides a synergistic effect greater than the sum of the parts. In addition, since the impact of these phyto­chemicals is dependent on how much of each compound the body actually absorbs, Dr. Murphy and colleagues will also be looking to see if the combination of curcumin and quercetin allows more of either or each ingredient to convert into actively circulating material in genetically-engineered mice.

“This is a great opportunity for us to look more closely at inflammation and cancer at the cellular level,” she said, “and possibly add some scientific evidence” to the already significant anecdotal and traditional heritage of two traditional plant-based medicines.