A concentrated cannabis extract has shown "remarkable" potential to kill off the most dangerous type of skin cancer.
It's still early days, but if the results can be replicated in living animal models and then in humans, it could provide a whole new drug avenue for a disease that is currently difficult to treat: melanoma.
The cannabis oil in question is known as PHEC-66, and it was developed by MGC Pharmaceuticals in Australia.
In October 2023, the company funded a study that found PHEC-66 stopped isolated melanoma cell lines from proliferating in the lab.
Follow-up research, led by scientists at RMIT University and Charles Darwin University (CDU), has now confirmed those results. Findings from the team suggest that this particular Cannabis sativa extract stops melanoma cells from multiplying, by forcing the disease to kill itself.
"The damage to the melanoma cell prevents it from dividing into new cells, and instead begins a programmed cell death, also known as apoptosis," explains biomedical scientist Nazim Nassar from CDU.
Whether this works in a living animal body is a whole other matter that still needs to be investigated. There have been no clinical trials conducted with cannabis oil to date, and high-quality research on the cancer-fighting potential of cannabis compounds remains scant.
Humans have used cannabis as medicine for millennia, and yet modern stigma in the past century or so has seriously hampered scientific research.
Only in 2016 did Australia legalize the use of cannabis for medicinal purposes, allowing teams to investigate the potential of the drug for treating a plethora of illnesses and diseases.
In the last few years alone, researchers in Australia have found great potential for cannabis in killing certain types of cancerous cells, all without impacting normal, healthy cells.
In 2020, for instance, a biotech company in Australia found that some cannabis varieties can induce death in leukemia cells in the lab, supporting research from elsewhere in the world going back more than a decade.
In 2015, scientists in the US found that when the cannabinoid receptors on non-melanoma skin cancer cells were targeted, the cells began to suffer from oxidative stress, leading to programmed cell death.
A few years before, researchers in Italy found that cannabis compounds showed similar outcomes in fighting pancreatic cancer.
Melanoma is now added to the list.
"This is a growing area of important research because we need to understand cannabis extracts as much as possible, especially their potential to function as anticancer agents," argues Nazar.
"If we know how they react to cancer cells, particularly in the cause of cell death, we can refine treatment techniques to be more specific, responsive and effective".
The outcomes of the current study suggest that PHEC-66 triggers programmed cell death by inducing DNA fragmentation, halting cell growth by division, and "substantially elevating" intracellular reactive oxygen species (ROS) levels.
ROS are short-lived yet highly reactive molecules that, when elevated, can cause damage to many different parts of a cell. If the damaged cell reaches a point of no return, it may even sacrifice itself for the 'greater' good.
In the lab, PHEC-66 seems to increase the likelihood of apoptosis occurring in three melanoma cell lines, by targeting cannabinoid receptors and allowing ROS to accumulate within the cell.
Further studies on animals are now needed to see if the results apply to cancerous cells in living models. Researchers, for instance, still need to figure out how to apply the medicine and in what dosage.
Only then can clinical trials on humans even be considered.
Today, research on most cannabis compounds is still confined to the lab, and while initial experiments suggest some cannabinoids can block cell growth and cause cell death, other candidates seem to actually encourage cancer cell growth.
There are hundreds of cannabinoid compounds in the cannabis plant, and researchers have only brushed the surface of their medicinal potential.
It's far too early to say if the cannabis plant will help drive future cancer treatments, but when it comes to deadly, hard-to-treat diseases like melanoma, there's every reason to keep digging.
The study was published in Cells.