Cannabinoids are currently used in cancer patients to palliate wasting, emesis and pain that often accompany cancer. A significant advancement in cannabinoid use in cancer treatment came from the discovery of a potential utility of these compounds for targeting and killing cancer cells.
Multiple sclerosis and spinal cord injury, neuropathic pain, cancer, atherosclerosis, stroke, myocardial infarction, hypertension, glaucoma, obesity/metabolic syndrome and osteoporosis are some of the diseases in which alterations in the eCB system have been demonstrated, thus paving the way for new therapeutic strategies aimed at restoring normal eCB system functionality.
Currently, the term ‘cannabinoid’ refers to more than 100 terpenophenols derived from Cannabis sativa, as well as to synthetic compounds that directly or indirectly interact with cannabinoid receptors.
Cannabinoids are currently used in cancer patients to palliate wasting, emesis and pain that often accompany cancer. A significant advancement in cannabinoid use in cancer treatment came from the discovery of a potential utility of these compounds for targeting and killing cancer cells. In 1975 Munson et al. demonstrated the administration of THC and cannabinol inhibited the growth of Lewis lung adenocarcinoma cells in vitro as well as in vivo after oral administration in mice. The interest in anticarcinogenic properties of cannabinoids was renewed after the discovery of the eCB system and the cloning of the specific cannabinoid receptors. Since then, several cannabinoids have been shown to exert anti-proliferative and pro-apoptotic effects in various cancer types (lung, glioma, thyroid, lymphoma, skin, pancreas, uterus, breast, prostate and colorectal carcinoma) both in vitro and in vivo. Moreover, other antitumourigenic mechanisms of cannabinoids are currently emerging, showing their ability to interfere with tumour neovascularization, cancer cell migration, adhesion, invasion and metastasization.
However, the clinical use of THC and additional synthetic agonists is often limited by their unwanted psychoactive side effects, and for this reason interest in non-psychoactive phytocannabinoids, such as CBD, has substantially increased in recent years. Interestingly CBD has no psychotropic activity and, although it has very low affinity for both CB1 and CB2 receptors, it has been recently reported to act with unexpectedly high potency in vitro as antagonist of CB1 receptors in the mouse vas deferens and brain tissues.
Furthermore, CBD can be considered as an alternative agent for breast cancer therapy, and CBD has actually been shown to shrink and kill breast cancer cells.
CBD also possesses anti-tumoural properties in the treatment of glicoma. Interestingly, combined treatment of THC with CBD demonstrated that CBD enhanced the THC inhibitory effect on glioblastoma cell growth. Thus, actually curing the glicoma.
CBD and leukemia/lymphoma. Research Results suggest CBD, acting through CB2 receptors and ROS production, may represent a novel and highly selective treatment for leukemia. Moreover, previous evidence indicated that human leukemias and lymphomas expressed significantly higher levels of CB2 receptors compared with other tumour cell lines, suggesting that tumours of immune origin may be highly sensitive to the CB2-mediated effects of CBD.
CBD and lung cancer. Research findings suggest a novel mechanism underlying the anti-invasive action of CBD on human lung cancer cells and imply its use as a therapeutic option for the treatment of highly invasive lung cancers.
Colon cancer is a major cause of morbidity and mortality in Western countries. Research suggests CBD might be worthy of clinical consideration in colon cancer prevention.
Conclusion and future directions
Evidence is emerging to suggest that CBD is a potent inhibitor of both cancer growth and spread.
Interestingly, the anticancer effect of this compound seems to be selective for cancer cells, at least in vitro, since it does not affect normal cell lines. The efficacy of CBD is linked to its ability to target multiple cellular pathways that control tumor growth through the modulation of different intracellular signaling --- dependent on the cancer type.
Finally, the use of CBD/Sativex can be suggested in combination with classical chemotherapeutic agents to check for the presence of a synergistic effect that might potentially allow clinical chemotherapeutic dose reduction, thereby reducing toxicity while maintaining efficacy. In the light of its safety record and considering that CBD is already currently used in patients with multiple sclerosis, the findings here summarized suggest that CBD might be worthy of clinical consideration for cancer therapy.
What this research suggests is that cannabis whether CBD alone or in combination with THC can be an effect treatment for some of the most profound illnesses facing modern medicine. Furthermore, the limits of medicinal uses for cannabis may be far more extensive and far reaching than anyone knew. Thus, companies developing treatments and orphan drugs based on the cannabis molecules may not yet know their limitations. To suggest the medicinal benefits derived from cannabis is exponential is putting it mildly.
British Journal of Clinical Pharmacol. 2013 Feb; 75(2): 303–312.
Published online 2012 Apr 17. doi: 10.1111/j.1365-2125.2012.04298.x
Cannabidiol as potential anticancer drug
Paola Massi,1 Marta Solinas,2 Valentina Cinquina,2 and Daniela Parolaro2