AACR Journals (American Association for Cancer) published the results of a study done by Katherine A. Scott, Angus G. Dalgleish and Wai M. Liu. The study was funded by a research grant awarded to W.M. Liu from GW Pharmaceuticals Ltd., Salisbury, United Kingdom.
The study looked into the effect of Cannabidiol (CBD) and Δ9-Tetrahydrocannabinol (THC) in combination with radiation on brain tumors.
Tumors and cannabinoids
Glioma, a malignant tumor of the glial tissue of the nervous system, is considered one of the most aggressive cancers in adult humans, and survival rates are very low. U.K. stats show 36% of patients live at least a year, 10% survive for five years. More aggressive glioma mostly falls below a year in terms of survival time.
Surgery is usually the first option followed by radiotherapy and/or chemotherapy depending on the accessibility of the tumor. The intricate nature of these tumors in the brain, and their invasive or aggressive behavior leaves treatment mostly unsuccessful. The importance of developing new treatment is of crucial importance. Cannabinoids have shown effect in the disease, and calls for further investigation to establish the clinical value of these possible therapeutic agents have been made.
The term “cannabinoids” is used to describe a group of compounds, which occur naturally in Cannabis plants more specifically Cannabis sativa and Cannabis indica. The major compound in the diverse group, which has been in the spotlight of research, is Δ9-Tetrahydrocannabinol (THC), the psychoactive of the cannabis plant. It was isolated in the sixties, and has shown to have strong interaction with cannabinoid receptors in a wide variety of tissues. Of late many studies in vitro and in vivo recognize potential anticancer potential in reducing tumor growth. Cannabinoids are also established as antiangiogenic and anti-inflammatory agents.
The psychoactive effect of THC has been a hindrance to trials being conducted as it is controversial, but despite that, a pilot trial in glioblastoma multiforme patients (an advanced type of glioma) showed feasibility without apparent psychoactive effects.
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CBD shows anticancer activity
CBD and cannabigerol (CBG), other prominent cannabinoids, also show anticancer activity, but have no psychoactive effects. The bioactivity seems similar to THC, yet it seems their action is not dependant on receptor activation to deliver anticancer activity. This is an obvious win-win for scientists as CBD maximizes anticancer action and at the same time minimizes psycho activity.
This evidence has put CBD high on the priority list as an anticancer treatment over the past few years. Studies looked at single agents or a combination of cannabinoids, and other treatments on a number of different types of cancer cells. In 2013 clinical trials on Sativex, a 1:1 CBD and THC preparation were conducted.
CBD and THC in combination enhances the effects of radiation therapy
The study under discussion looked into the benefit of combining cannabinoids with γ-irradiation. The study wanted to determine if cannabinoids could prime cells to irradiation, and in particular if the cannabinoids should be used individually, or together.
Cells were pretreated for four hours in combination, and separately before ionizing radiation. Cells were planted into plates, and colony growth was evaluated after two weeks. Results showed there were no difference in cells pretreated with either CBD or THC, but there was a trend towards smaller fractions of cancer cells surviving when CBD and THC were used in combination.
The effect of these cannabinoids on DNA double-strand breaks caused by irradiation was also assessed, and results showed that irradiation enhanced the actions of the cannabinoids.
Cannabinoids and irradiation hindered tumor growth
The combination of cannabinoids and irradiation hindered tumor growth, which stagnated during the course of the experiment, and tumor size in these animals were smaller by the final day. Ex vivo dissection of the brains showed the tumors were denser and appeared less bullish.
The study sums up that data obtained in support of the hypothesis that cannabinoids alone or in combination possess anticancer properties. The in vivo results of a combination of cannabinoids and irradiation were astounding and significantly inhibited tumor growth.
It is now of utmost importance to expand the study, and work is ongoing.
CBD oil for cancer
The study shows CBD oil for certain cancers has great efficacy, but it is done in vitro (in a lab) next it will have to be thoroughly tested on animals, and results will only be considered conclusive once clinical trails are conducted…. This might still take years and years, but at least the preliminary results have been promising.