Cannabinoids may be useful in preventing colon cancer, researchers find

Treatment with Δ9-tetrahydrocannabinol (THC), a cannabinoid found in the cannabis plant, prevented the development of colon cancers in mice, according to a new study by the University of South Carolina published in iScience.

Inflammatory bowel diseases (IBD) such as Crohn's disease and ulcerative colitis are caused by unrestrained inflammation of the gastrointestinal tract. Patients with IBD are at a higher risk of developing colorectal cancer. The study that THC suppressed inflammation in the colon, preventing the onset of cancers caused by a carcinogen.

The incidence of IBD is increasing globally, the researchers said. This suggests that the risk of cancers that are linked to IBD also are going to increase. In fact, the risk of colon and rectal cancers is increasing among young and middle-aged adults in the United States and the cause remains unknown. Thus, understanding the mechanisms of IBD and developing effective drugs to prevent IBD and associated cancers are crucial, the researchers said.

The new paper is based on research studies from the laboratories of Prakash Nagarkatti, PhD, and Mitzi Nagarkatti, PhD, at the University of South Carolina School of Medicine Columbia Department of Pathology, Microbiology, and Immunology.

The researchers have previously studied the anti-inflammatory properties of cannabinoids. The cannabinoids act through two receptors known as CB1 and CB2. The CB1 receptor is expressed in the brain where THC activation causes psychoactive effects. The second receptor, CB2, is expressed mainly on the immune cells, meaning that activation of CB2 receptors does not trigger psychoactivity.

"Our results showed that THC was acting through CB2 receptors,” said Mitzi Nagarkatti in a statement, “which is exciting and suggests that compounds that activate CB2 and cause no psychoactive effects may be beneficial to prevent IBD and colon cancer.”