THC, the major active component of cannabis (also known as marijuana), has anti-cancer properties. This compound is known to act through a specific family of cell receptors called cannabinoid receptors. When human tumors in mice were targeted with doses of THC, the researchers found that 2 cell receptors were particularly associated with an anti-tumor response.
Previous studies have suggested that cannabinoids, of which tetrahydrocannabinol (THC) is one, have anti-cancer properties. In 2009, researchers at Complutense University in Spain found that THC induced the death of brain cancer cells in a process known as “autophagy.”
The researchers found that administering THC to mice with human tumors initiated autophagy and caused the growth of the tumors to decrease. Two human patients with highly aggressive brain tumors who received intracranial administration of THC also showed similar signs of autophagy, upon analysis.
“We show that these effects are mediated via the joint interaction of CB2 and GPR55 – two members of the cannabinoid receptor family. Our findings help explain some of the well-known but still poorly understood effects of THC at low and high doses on tumor growth,” they said.
However, the team is unsure which receptor is the most responsible for the anti-tumor effects.
There is already a “great deal of interest” in understanding the molecular mechanisms behind how marijuana influences cancer pathology. This has been accompanied by a drive in the pharmaceutical industry to synthesize a medical version of the drug that retains the anti-cancer properties.
By identifying the receptors involved, an important step will be made towards the future development of therapeutics that can take advantage of the interactions found to reduce tumor growth.
The National Cancer Institute on cannabis medicinal use
The National Cancer Institute has recently confirmed that cannabis can kill cancer cells after the drug did so in tests on mice and rats. The development of an FDA approved drugs will provide further ammunition for cannabis pro-legalization campaigners.
On its website, The National Cancer Institute, which is part of the US Department of Health, said: “Laboratory and animal studies have shown that cannabinoids (the active ingredient in cannabis) may be able to kill cancer cells while protecting normal cells. They may inhibit tumor growth by causing cell death, blocking cell growth, and blocking the development of blood vessels needed by tumors to grow.”
The studies in rodents clearly showed that cannabinoids may reduce the risk of liver, colon and breast cancer, and could effectively supplement chemotherapy.
But researchers added: “At this time, there is not enough evidence to recommend that patients inhale or ingest cannabis as a treatment for cancer-related symptoms or side effects of cancer therapy.“
Patients diseased with some type of cancer have long been using the drug to ease their pain in a number of US states where cannabis is already legal for medicinal application. The Cancer Research Charity reacted cautiously, saying that there was no evidence of a similar effect in humans. Their spokesman said: “There isn’t enough reliable evidence to prove that cannabinoids, whether natural or synthetic, can effectively treat cancer in patients, although research is ongoing around the world.“ The charity has also warned patients to be wary of fraudsters selling cannabis treatments.
Why patients should not ‘self-medicate’ with marijuana
Cancer patients should not be tempted to self-medicate, researchers and doctors alike have warned:
“Our research uses an isolated chemical compound and using the correct concentration is vital. Cancer patients should not use cannabis to self-medicate, but I hope that our research will lead to a safe synthetic equivalent being available in the future.“
Medical marijuana has been in the news a lot over the past week, with Governor Andrew Cuomo signing the Compassionate Care Act, which makes New York the 23rd state to legalize the medical use of this drug.
Medical News Today also recently reported on how the city of Berkeley in California – which was the first state in the US to allow the medical use of marijuana, back in 1996 – has passed a law that requires the four marijuana dispensaries in the city to provide free medical marijuana to low-income patients who have been prescribed this medication.
Meanwhile, Arizona has broadened the range of conditions for which medical marijuana can be prescribed as a treatment. As well as conditions such as cancer, chronic pain and muscle spasms, marijuana can now be prescribed as a form of palliative care for post-traumatic stress disorder.
Here is an overview: Cannabis and Cannabinoid s – for health professionals
This complementary and alternative medicine (CAM) information summary provides an overview of the use of cannabis and its components as a treatment for people with cancer –related symptoms caused by the disease itself or its treatment.
This summary contains the following key information:
- Cannabis has been used for medicinal purposes for thousands of years.
- By federal law, the possession of Cannabis, also known as marijuana, is illegal in the United States; however, a growing number of states and the District of Columbia have enacted laws to legalize its medical use.
- The U.S. Food and Drug Administration has not approved Cannabis as a treatment for cancer or any other medical condition.
- Chemical components of cannabis, called cannabinoids, activate specific receptors found throughout the body to produce pharmacologic effects, particularly in the central nervous and the immune system.
- Commercially available cannabinoids, such as dronabinol (a pharmaceutical form of THC) and nabilone (a man-made cannabinoid), are approved drugs for the treatment of cancer-related side effects.
- Cannabinoids may have benefits in the treatment of cancer-related adverse effects.
Bottom line: Utmost caution must be exercised when using cannabis for treating cancer in humans.