Cannabis-Based Therapies Without the Side Effects: A New Treatment Paradigm for Cancer?

Recent research has indicated that THC, the primary psychoactive ingredient in cannabis, reduces tumor growth in animal models. However, cannabis use is also associated with unwanted side effects, such as memory loss, alterations in mood and perception, and dependence. Recently, scientists at the University of East Anglia (UEA) and the University Pompeu Fabra in Barcelona, Spain identified that inhibition of a signaling pathway in the brain, involving both a cannabinoid receptor and a serotonin receptor, prevented the undesirable side effects of THC while maintaining its therapeutic potential. These findings were published in the July 2015 issue of the journal PLOS Biology.

The research team performed behavioral studies in wild-type mice and mice lacking the serotonin receptor 5-HT_2A. They found that memory deficits, anxiolytic-like effects, and social interaction were under the control of this 5-HT_2A receptor, but the acute hypolocomotor, hypothermic, anxiogenic, and antinociceptive effects were not. Therefore, administration of THC to these mice promoted pain relief without the amnesia observed in the normal animals. According to Dr. Peter McCormick, one of the study authors from the UEA School of Pharmacy, the research highlights a potential molecular signaling pathway through which “some of the drug’s beneficial effects can be separated from its unwanted side effects.”

Although McCormick indicates that patients should not attempt to self-medicate with cannabis, he suggests that identification of this pathway could be used for future development of a safer, synthetic form of cannabis for therapeutic purposes.

Read more: Vinals X, et al. Cognitive impairment induced by delta9-tetrahydrocannabinol occurs through heteromers between cannabinoid CB1 and serotonin 5-HT2A receptors. PLOS Biology. July 2015.