Cannabinoids: potential antitumoral agents?

Cannabinoids, the active components of Cannabis sativa L., act in the body by mimicking endogenous substances – the endocannabinoids – that activate specific cell surface receptors. Cannabinoids exert palliative effects in cancer patients. For example, they inhibit chemotherapy-induced nausea and vomiting, stimulate appetite and inhibit pain. In addition, cannabinoids inhibit tumor growth in laboratory animals. They do so by modulating key cell signaling pathways, thereby inducing antitumoral actions such as the apoptotic death of tumor cells as well as the inhibition of tumor angiogenesis. Of interest, cannabinoids seem to be selective antitumoral compounds as they can kill tumor cells without significantly affecting the viability of their non-transformed counterparts. On the basis of these preclinical findings a pilot clinical study of ∆9 -tetrahydrocannabinol (THC) in patients with recurrent glioblastoma multiforme has recently been run. The fair safety profile of THC, together with its possible growth-inhibiting action on tumor cells, may set the basis for future trials aimed at evaluating the potential antitumoral activity of cannabinoids. Key words: cannabinoid, receptor, tumor, cancer, apoptosis, angiogenesis, experimental therapeutics, clinical trial.