A cannabis extract called PHEC-66 possesses what researchers are calling “remarkable” anti-cancer effects, according to a new study from Australian researchers. In in-vitro trials, the extract was shown not only to slow the growth rates of melanoma cancer cells, but to also prompt their death.

The results "suggest that PHEC-66 triggers apoptosis in these melanoma cell lines by increasing the expression of pro-apoptotic markers (BAX mRNA) while concurrently reducing the expression of anti-apoptotic markers (Bcl-2 mRNA),” the study reports. “Additionally, PHEC-66 induces DNA fragmentation, halting cell progression at the G1 cell cycle checkpoint and substantially elevating intracellular ROS [reactive oxygen species] levels.”

To put it another way, as CDU pharmaceutical lecturer and study co-author Nazim Nassar explained in a press release on the findings, the extract binds to cancerous cells, stops them from multiplying, and forces them to kill themselves.

“The damage to the melanoma cell prevents it from dividing into new cells,” he said, “and instead begins a programmed cell death, also known as apoptosis.”

For a nigh-on quarter of a century now, cannabis and its derivatives have been increasingly recognized as having the potential to provide benefits for people with cancer. Usually, however, the advantages it gives are thought of as being mostly palliative in nature: it stops you from feeling so sick; helps reduce pain and anxiety; and gives you back an appetite.

But its usefulness as a treatment to actually battle the disease has remained disputed. “The short answer is that we simply don’t know yet if cannabis or any of the chemicals found in cannabis are useful to treat cancer,” explained postdoctoral cancer researcher Charlott Repschlaeger, who was not involved in the new study, in a video for Worldwide Cancer Research. “That’s because research into cannabis and its connection to cancer is still in its infancy.”

There are very few studies in humans, she pointed out, and those that do exist are often small and produce mixed results. Really, "the jury is still out,” she said.

Like other recent results that have shown promise for cannabis as a cancer therapy, the new study has only been conducted in vitro – that is, in a lab, in specially-cultured melanoma cells, rather than in people or animals. And to say the research is still in its early stages is putting it mildly: the team readily admits that they don’t actually know why the extract is effective, only that it is.

“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,” Nassar said. “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.”

That should hopefully soon change, however, as the team hopes to be able to develop appropriate delivery systems and conduct follow-up trials for the extract.

“The subsequent stage involves animal studies or pre-clinical trials to validate and further explore the efficacy of cannabinoid PHEC-66 in treating melanoma and other cancers,” said Nitin Mantri, professor of biotechnology at RMIT (Royal Melbourne Institute of Technology) University and lead author of the study. 

Despite the controversy around the use of cannabis as a cancer treatment – or, perhaps, because of it – the researchers have high hopes for the extract. Of course, it's worth noting that they have skin in the game: this study owes its funding to MGC Pharmaceuticals Limited, the same company responsible for producing the extract in the first place. 

Nevertheless, should it prove safe and effective, this once-stigmatized therapy may be able to revolutionize cancer treatment, Nassar said.

“Clinical uses of cannabis extracts include treatment for anxiety, cancer-related symptoms, epilepsy, and chronic pain,” he pointed out. “Intensive research into its potential for killing melanoma cells is only the start as we investigate how this knowledge can be applied to treating different types of cancers.”

The study is published in the journal Cells.