Scientists have identified several cannabinoid compounds that could potentially treat colorectal cancer. A team at Pennsylvania State University College of Medicine in Hershey tested hundreds of cannabinoids on various types of human colorectal cancer cells in the laboratory. Of these, 10 synthetic cannabinoids showed the ability to stop cancer cell growth. The well-known cannabis compounds tetrahydrocannabinol (THC) and cannabidiol (CBD) showed negligible ability to do the same.
The researchers see their findings as a starting point for further studies to better understand the anticancer effects that they observed, and to evaluate the compounds' potential for drug development. They report their results in a paper that features in the journal Cannabis and Cannabinoid Research. "Now that we've identified the compounds that we think have this activity," says senior study author Prof. Kent E. Vrana, who is chair of the Department of Pharmacology, "we can take these compounds and start trying to alter them to make them more potent against cancer cells." "And then, eventually, we can explore the potential for using these compounds to develop drugs for treating cancer," he adds.
According to the World Cancer Research Fund, colorectal cancer is the "third most common cancer worldwide." This is also the case in the United States, where a national surveillance program has estimated that colorectal cancer accounted for 8.1 percent of all new cancer incidences in 2018.
For several decades, overall rates of colorectal cancer diagnoses and deaths have been falling steadily in the U.S. Experts attribute this largely to changes in risk factors, more widespread screening, and better treatments. However, this overall decline masks an opposite trend in that rates and deaths to colorectal cancer are rising among those of 50 years of age and under. The reasons for this remain unclear, although some suggest that obesity, changes in diet, and an increase in sedentary lifestyles may be involved.
Cannabinoids is a term that scientists use to refer to a large group of compounds that mostly exert their effect through cannabinoid receptors. There are three main categories of cannabinoids. Phytocannabinoids are those that occur naturally in the cannabis, or marijuana, plant; endocannabinoids are those that arise within the body; while synthetic cannabinoids are those that scientists create in the laboratory. Research on the medical uses of cannabinoids has tended to focus on the treatment of pain and conditions such as anxiety and depression. However, more recently, scientists have shown growing interest in the potential anticancer effects of cannabinoids.
The 10 compounds belong to three different classes of synthetic cannabinoid. The classes have many similarities, but they also have some small differences. Prof. Vrana says there is a need for further research to understand better how the compounds work, and how to make them more potent and effective against colorectal cancer. “We also found that the most potent and effective compounds don't seem to work through traditional marijuana receptors, although we're not sure of the exact mechanism yet."
This is the kind of research that could have been done years ago if marijuana was not classified as a Class 1 drug, without any potential medical benefit. Fortunately, as state laws have changed, so have attitudes about this herb and the needed research is beginning.
Federal laws classifying marijuana as a Class 1 drug need to be changed to promote research.
Source: February 13, 2019 NIH