How Cannabis Was Used To Shrink One Of The Most Aggressive Brain Cancers

"Marijuana" by United States Fish and Wildlife Service - [1], specifically CASA1_LF.jpg.


by Wai Liu

on November 16, 2014

The following story first appeared on The Conversation. It’s written by Dr Wai Lui, a Senior Research Fellow at St George’s, University of London, who was the lead researcher on a study which investigated the anti-cancer effects of Sativex in glioma cells. Here he describes his work in detail.

Widely proscribed around the world for its recreational uses, cannabis is being used in a number of different therapeutic ways to bring relief for severe medical conditions. Products using cannabinoids, the active components of the cannabis plant, have been licensed for medical use. Sativex, for example, which contains an equal mixture of the cannabinoids tetrahydrocannabinol (THC) and cannabidiol (CBD), is already licenced as a mouth spray for multiple sclerosis and, in the United States, dronabinol and nabilone are commercially available for treating cancer-related side effects.

Now, in a study published in Molecular Cancer Therapeutics, we’ve also been shown that cannabinoids could play a role in treating one of the most aggressive cancers in adults.

There are more than 85 cannabinoids, which are known to bind to unique receptors in cells and which receive outside chemical signals. These receptors feed into signalling pathways, telling cells what to do. Recent studies have shown that some cannabinoids have potent anti-cancer action. For example, both THC and CBD have been shown in a number of laboratory studies to effectively induce cell death in tumor cells by modifying the faulty signalling pathways inside these cells. Depending on the cell type, this can disrupt tumor growth or start to kill it.

The psychoactivity associated with some cannabinoids, principally THC (which gives people a cannabis high), is also mediated via the same receptors. Because these receptors are found in the highest abundances in brain cells, it follows that brain tumors also rich in these receptors may respond best to cannabinoids.

We wanted to investigate the anti-cancer effects of Sativex in glioma cells. High-grade glioma is an aggressive cancer, with very low long-term survival rates. Statistics show that just over a third (36%) of adult patients in the UK with glioma live for at least a year, while the five-year survival rate is 10%.

Depending on the individual, treatment can consist of surgery, radiotherapy, and/or chemotherapy with the drug temozolomide. However, due primarily to the intricate localisation of the tumor in the brain and its invasive behaviour, these treatments remain largely unsuccessful.

However, as our study showed, combining radiotherapy with cannabinoid treatment had a big effect.

Finding The Right Dose

We first had to perform lab tests on cells to optimise the doses of the cannabinoids, and showed that CBD and THC combined favourably.

We found that to achieve a 50% kill rate of glioma cells, a dose of 14mM (millimolar — a measure of amount-of-substance concentration) of CBD or 19mM of THC would be needed if each was used singularly. However, when used in combination, the concentrations required to achieve the same magnitude of cell kill is significantly reduced to just 7mM for each. This apparent reduction in the doses of the cannabinoids, in particular THC, without a loss of overall anti-cancer action is particularly attractive as unwanted side effects are also reduced.

Once we had these results, we then tested the impact of combining the cannabinoids with irradiation in mice with glioma. The efficacy of this treatment was tracked using sophisticated MRI technology — and we determined the effects on tumor growth of either CBD and THC together, irradiation, or the combination of both. The drugs were used at suboptimal doses to allow us to see if there was any improvement in the therapy from combining them.

Balancing Anti-Cancer With Psychoactive

In principle, patients treated with THC could experience some psychoactive activity. But the secret to successfully exploiting cannabinoids as a treatment for cancer is to balance the desired anti-cancer effects with the less desirable psychoactive effects. This is possible, as some cannabinoids seem to function independently of the receptors and so do not engage the adverse effects. CBD is one such cannabinoid. The doses of THC we selected were below the psychoactive level, but together with CBD it partnered well to give the best overall anti-cancer effect.

Our results showed that the dose of irradiation we used had no dramatic effect on tumor growth, whereas CBD and THC administered together marginally reduced tumor progression. However, combining the cannabinoids with irradiation further impeded the rate at which tumor growth progressed and was virtually stagnant throughout the course of the treatment. Correspondingly, tumor sizes on the final day of the study were significantly smaller in these subjects compared with any of the others.

The results are promising. There may be other applications but for now it could provide a way of breaking through glioma and saving more lives.

there are 4,527 Comments

David Taglieri

Jersey Shore

I am happy (personally) to see the use of the word “Cannabis” used in your headline… and not the propagandized label “Marijuana”. As a 44 year old, only up to a few years ago I too believed everything our government said about “Reefer Madness, Your Brain On Drugs and the implementation of D.AR.E. to educate myself against the alleged dangers of marijuana, its culture and the crime and violence it leads to (Allegedly).

After further research and learning online… Like so many others have learned, this is completely untrue, unproven, false in and in so many instances outright fraud against the American people. We have formed laws around a plant that has been falsely reviewed by our own government, in order to protect the citizens against its dangers. Got it.

The people are slowly awakening to these deceptions in many areas of the alphabet government. The result, more states voting in favor of cannabis. (Let’s not call it marijuana;-)

Next up… change the name of cannabis flowers to something informative and understanding to the general public, and less bootlegger streetcorner terms. Like Nutritional Facts found on the label of a soup can, know the content. If the flowerbud is sativa use the letter “S”. If it’s indica, the letter “I”. On a hybrid, you show both with the more dominant strain in capital and the other as lowercase. Label the THC and CBD levels next. Example “iS-16/0.3” represents a Sativa strong hybrid with 16% THC and 0.3% CBD. I feel this sounds more promising in value than “Trainwreck”. It’s all perception. If we want this plant to be accepted, we must each begin by changing peoples views.

I’ve begone,


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