Last updated October 25, 2018 at 3:02 pm
Cannabidiol and chemotherapy shows dramatic results in mice.
Credit: Tilray
Cannabidiol, a naturally occurring compound found in cannabis, has been found to vastly increase the survival of mice with pancreatic cancer when used in combination with chemotherapy, a new study has revealed.
Pancreatic cancer is one of the most aggressive and least survivable cancers – in Australia only around 7.7% of patients survive five years.
Nearly 3,000 new cases of pancreatic cancer were diagnosed in Australia in 2013.
Mice that were treated with the compound, which is non-psychoactive, alongside chemotherapy survived almost three times longer than those treated with chemotherapy alone.
Used individually, the chemotherapy drug was more effective than cannabidiol, however the researchers say that when used together, cannabidiol could boost the effect of the chemotherapeutic agent.
‘Remarkable result’
The study was led by Professor Marco Falasca from Curtin University in Western Australia.
“This is a remarkable result,” he said.
In the study, cannabidiol was used alongside gemcitabine, a common chemotherapeutic used in pancreatic cancer. The form of pancreatic cancer in mice closely resembles the human disease.
“We found that mice with pancreatic cancer survived nearly three times longer if they were treated with both a type of cannabinoid known as cannabidiol and the popular chemotherapy medication gemcitabine,” Professor Falasca said.
“This study shows that chemotherapy treatments for mice with pancreatic cancer was enhanced with the use of a particular constituent of medicinal cannabis.”
Combination therapy most effective
The researchers showed that the protein receptor GPR55 is involved in promoting the growth and proliferation of pancreatic cancer, with it being found in increased quantities in around 26% of pancreatic cancer samples. When they reduced the amount of GPR55, or blocked its activity, they found they could reduce the growth of the pancreatic cancer cells.
Credit: UBC Okanagan
The researchers then turned to mice genetically modified to develop pancreatic cancer to examine the effect of cannabidiol, which is known to block GPR55.
One group of ten mice was given cannabidiol, eight were given the chemotherapy drug gemcitabine, and seven mice were given both drugs in combination.
A fourth group of nine mice were given an inert placebo.
The placebo group mice, who were given no active treatment, survived on average for 19 days. While the group which were given just cannabidiol survived longer – 25 days, cannabidiol alone wasn’t as effective as gemcitabine, with the group given the chemotherapy drug surviving for 28 days.
However it was the group given the combination of cannabidiol and gemcitabine which showed the most dramatic improvement, surviving on average for 53 days.
It is thought that the blocking of GPR55 increases the effectiveness of gemcitabine by reducing factors that promote the growth of the cancer cells.
What’s more, the researchers say cannabidiol opposes the development of resistance by the cancer cells to gemcitabine.
As promising as these findings are, the small size of the study should however be noted.
Hopes for human trials
Cannabidiol is non-psychoactive, meaning it doesn’t affect brain function unlike tetrahydrocannabinol (THC), the known psychoactive ingredient in cannabis. Facing fewer regulatory hurdles as some cannabis products, it is already approved for use with a prescription from a doctor, raising hopes that it could be tested in humans almost immediately.
“If we can reproduce these effects in humans, cannabidiol could be in use in cancer clinics almost immediately, compared to having to wait for authorities to approve a new drug,” said Falasca.
“The life expectancy for pancreatic cancer patients has barely changed in the last 40 years because there are very few, and mostly only palliative care, treatments available. Given the five-year survival rate for people with pancreatic cancer is less than seven per cent (in the UK), the discovery of new treatments and therapeutic strategies is urgently needed.”
This finding adds to the benefits of cannabidiol, which is already known to reduce the side effects of chemotherapy, including nausea, diarrhoea, vomiting.
The research has been published in Oncogene
The research was supported by the UK charity Pancreatic Cancer Research Fund and the Avner Pancreatic Cancer Foundation.
