Researchers have identified a CBD rich chemovar that is very good at killing cancer cells.
There has been a surge of interest in studying the effectiveness of cannabinoids for cancer treatment over the last couple of years. Both of the major cannabinoids, THC and CBD, have shown promise in laboratory studies of several cancer cell lines and in vivo models. But, one may be starting to pull away from the other. In addition to sparing a cancer patient from the potentially unwanted side effects of the associated ‘high’, researchers have found that CBD may be more effective than THC at reducing tumor growth. This includes a three-year-long project recently completed by Dr. Matt Dun and the Australian Natural Therapeutics Group (ANTG) which found that their new high CBD cannabis strain for cancer, called ‘Eve’, killed or inhibited cancer cells without harming normal cells. The study adds to the litany of preclinical evidence that supports cannabis as a safe alternative or complementary cancer treatment.
Researchers Find CBD is Effective Against Tumors
Research has shown that CBD is effective for treating multiple cancer cell lines,[1]Turgeman, I., & Bar-Sela, G. (2019). Cannabis for cancer–illusion or the tip of an iceberg: A review of the evidence for the use of Cannabis and synthetic cannabinoids in oncology. Expert … Continue reading But, how does it fare compared to THC? In a study published in Current Oncology (2016), the researchers tested the efficacy of THC and CBD on neuroblastoma cancer cell invasiveness, cell viability, and tumor growth.[2]Fisher, T., Golan, H., Schiby, G., PriChen, S., Smoum, R., Moshe, I., … & Mechoulam, R. (2016). In vitro and in vivo efficacy of non-psychoactive cannabidiol in neuroblastoma. Current … Continue reading
In the first in vitro part of the project, both THC and CBD demonstrated anti-cancer effects, but CBD was superior. CBD killed most of the cancer cells within twenty-four hours, and after forty-eight hours, almost all the cells were killed. Furthermore, compared to non-treated cells, CBD significantly reduced cell invasiveness. After microscopic analysis, the researchers determined that these anti-cancer effects were mediated by apoptotic cell death. The CBD treatment resulted in the cells losing their normal shape, becoming swollen, and dying.
In the second in vivo part of the study, the researchers induced neuroblastoma tumors in mice and subsequently treated the mice with either THC or CBD. Similar to the in vitro findings, CBD and THC treated mice experienced a dramatic reduction in tumor growth. However, CBD was more effective. The CBD treated tumors had a median size of 2.31 cm3 compared to 3.46cm3 for THC-treated mice. The authors noted that in addition to greater efficacy, CBD has other major advantages. Dr. Matt Dun agrees.
New High CBD Cannabis Strain Does Not Impact Normal Cells
“There are trials around the world testing cannabis formulations containing THC as a cancer treatment, but if you’re on that therapy your quality of life is impacted…you can’t drive, for example, and clinicians are justifiably reluctant to prescribe a child something that could cause hallucinations or other side effects,” Dr. Dun said. If equally, or more effective than THC, CBD is clearly the better cannabinoid for the job. He began testing the new cannabis strain, containing less than one percent THC, on leukemia cells. He found that the cancer cells were extremely sensitive to the high CBD strain, and importantly, there was no effect on healthy bone marrow or white blood cells. After realizing that there was a cancer-selective mechanism involved, he has been searching for the answer.
What’s Next for The ‘Eve’ Strain?
The next steps for the project are to identify what makes cancer cells sensitive to the new cannabis strain, but normal cells not. The researchers need to determine if the effects are clinically relevant, as well as whether multiple cancers respond to the treatment. The pathophysiology of cancers is unique. What works for one may not work for the other. “We need to understand the mechanism so we can find ways to add other drugs that amplify the effect, and week by week we’re getting more clues. It’s really exciting and important if we want to move this into a therapeutic” Dr. Dun stated, pointing out that the new cannabis strain is not yet ready for clinical use.
New Strain Not Ready for Clinical Use – Yet
Successful preclinical outcomes like this are exciting, but it is important not to get ahead of the research. The end goal of Dr. Dun’s research will be to test the effectiveness of ‘Eve’ in a human population. But, there are many checks and balances on the long road to human research. “Hopefully our work will help to lessen the stigma behind prescribing cannabis, particularly varieties that have minimal side-effects, especially if used in combination with current standard-of-care therapies and radiotherapy. Until then, though, people should continue to seek advice from their usual medical practitioner.”
As of now, cannabis, including CBD, is acknowledged for managing cancer-related side effects, such as pain, nausea, or vomiting. One day, CBD may enter the ring in the fight against cancer, but researchers like Dr. Dun have lots of work to do before then.
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