Second only to skin cancer, colon cancer is the most common cancer diagnosed in both men and women in the US. Now, researchers from the University of South Carolina have found that tetrahydrocannabinol (THC), the psychoactive compound in cannabis, can prevent colon cancer linked to ulcerative colitis in mice.
For the study, the researchers split mice with colitis-associated colon cancer into two groups. One was treated with THC and the other: a placebo. By the end of the study, they found that those treated with THC had no tumors, unlike those who received the placebo. Those in the THC group also had less inflammation in their colons, a symptom of inflammatory bowel disease.
The researchers say that THC has this effect as it binds to cannabinoid receptor type 2 (CB2), which is expressed in immune cells throughout the gastrointestinal system. This binding triggers an anti-inflammatory process, which makes intestinal cells secrete anti-inflammatory molecules instead of pro-inflammatory ones. These cells then help recruit regulatory T cells, a type of cell that can resolve inflammation and protect against cancer.
“The fact that we were able to show that treatment with THC prevents inflammation in the colon and at the same time inhibits the development of colon cancer supports the notion that inflammation and colon cancer are closely linked,” says Dr. Prakash Nagarkatti, a senior author of the study.
The researchers say that their findings suggest that people who are at higher risk of developing colon cancer may benefit from using THC or other anti-inflammatory agents. They warn, however, that their study indicates a preventative rather than a curative effect, and that it is too early to recommend cannabis to prevent colon cancer. As such, future efforts will likely focus on developing non-psychoactive compounds that can target CB2 receptors in the immune system similarly to THC.