Colon cancer is a malignant tumor occurring in the large intestine, one of the final portions of the digestive system. Most colon cancers develop from polyps in the colon, or small clumps of cells that form on the lining of the colon. However, polyps rarely have symptoms associated with them, so it can be difficult to predict the development of colon cancer. Once developed, symptoms of colon cancer include weakness and fatigue, changes in bowel habits, abdominal pain, weight loss, and shortness of breath. The lifetime risk of developing this cancer is approximately one in twenty, with colon cancer being the third leading cause of death in males and the fourth leading cause of death in females. Risk factors for colon cancer include family history, obesity and diabetes, low-fiber/high-fat diets, and inflammatory intestinal conditions. Recently, studies have uncovered another potential contributor to the development of colon cancer: the microbiome in our colon.
The bacteria in our gut is constantly evolving and changing in diversity, contributing to our overall health. In fact, our microbiome helps us obtain nutrients, contributes towards our immunity, protects us from infection, and maintains protective barriers. However, these bacteria also have the ability to form biofilms, or slime-like colonies of bacteria that stick together. An example of this would be the plaque that forms on teeth.
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The large intestine normally has a layer of mucous lining the inner surface of the gut. The formation of biofilms indicates a disruption to this healthy and normal mucous barrier. Interestingly, the formation of biofilms is linked to colon cancers primarily on the right-side of the body, where the colon is larger and more flexible. Furthermore, patients with colon cancers in the right-side are faced with higher levels of death than patients with colon cancers on the left. To explain this connection, researchers compared metabolic activities between cells in biofilm and normal colon cells by examining the metabolites, or by-products of metabolism, a process of chemical transformations within cells.
Certain metabolites, including a class called polyamine metabolites, were produced at increased levels in biofilm cells. These polyamine metabolites are linked to increased cellular division in humans and increased biofilm formation in bacteria. Although exact details have yet to be determined, a study recently published in Cell Metabolism proposed that polyamine metabolites from both humans and bacteria work together to promote the formation of biofilms and increased proliferation of human colon cells, ultimately contributing to the formation of colon cancer.
The success of potential colon cancer treatment by inhibiting the metabolism of polyamines is unclear; however, this study opens up the possibility of targeting both polyamine metabolites and biofilms to successfully treat colon cancer.