Cannabis compounds show unexpected power against ovarian cancer

"Ovarian cancer remains one of the deadliest gynecological malignancies, characterized by late diagnosis, high recurrence rates, and limited effective treatment options," said Dr. Siyao Tong of Khon Kaen University, lead author of the article in Frontiers in Pharmacology. "Our goal is to find alternative drugs that can improve efficacy and potentially reduce toxicity, ultimately bringing new hope to patients facing this challenging disease."

Why Current Treatments Fall Short

Of all gynecological cancers, ovarian cancer causes the highest number of deaths. Even with progress in medical care, available drugs often fail to produce long-lasting results and can cause severe side effects. Because new approaches are urgently needed, the researchers turned their attention to CBD (cannabidiol, which is not psychoactive) and THC (delta-9-tetrahydrocannabinol, which is), two cannabis-derived compounds that have shown signs of anti-cancer activity in other diseases.

The team worked with two ovarian cancer cell lines, one responsive to platinum-based drugs and one resistant, and exposed them to CBD, THC, or a combination of both. They also tested the compounds on healthy cells to determine whether normal tissue would be harmed.

CBD and THC Significantly Reduce Cancer Cell Growth

Cancer cells treated with either CBD or THC formed fewer colonies, and those colonies were smaller than usual. Both compounds slowed the ability of cancer cells to reproduce, but the strongest effects appeared when CBD and THC were used together. Although neither compound alone killed large numbers of cancer cells, the combination proved highly effective. This suggests that the two chemicals may influence cancer cells through different mechanisms, and these mechanisms may reinforce one another.

"Notably, the inhibitory effect was most pronounced when CBD and THC were used in a 1:1 ratio," said Tong.

Additional experiments showed that the compounds reduced cancer cell migration, an important finding because metastasis is a major cause of death in ovarian cancer. A therapy that limits the spread of cancer could significantly improve patient outcomes.

Potential for Less Toxic Cancer Treatments

Both cell lines responded similarly, indicating that the compounds might work across multiple ovarian cancer types. The cannabis-derived treatments also caused little harm to healthy cells, suggesting that future therapies based on these compounds might be easier for patients to tolerate than many current options.

To better understand why the compounds were effective, the researchers analyzed cancer cell signaling. They found that the PI3K/AKT/mTOR pathway, which is often overactivated in ovarian cancer and contributes to tumor progression and drug resistance, appeared to return to more normal activity after treatment with CBD and THC. This restoration of control may explain the reduced growth and increased cell death observed in the experiments.

Next Steps and Remaining Challenges

Despite the encouraging results, the scientists emphasize that far more research is needed before CBD or THC can be considered viable treatment options for ovarian cancer. Additional studies must determine whether these compounds can be safely and effectively used in clinical settings.

"Although our study is still preliminary, it lays an important foundation for future research into the potential applications of CBD and THC in ovarian cancer treatment," said Tong. "By confirming their anti-cancer activity and identifying key molecular mechanisms, our findings are expected to drive further preclinical research. If future studies confirm these effects, CBD-THC combination therapy may ultimately contribute to the development of new treatment strategies."

"However, this study has some limitations," Tong added. "All experiments were conducted in vitro, so the results may not fully reflect the complexity of tumor behavior in living organisms. We did not include in vivo models and pharmacokinetic data, which are crucial for determining whether CBD/THC can be safely and effectively used clinically. Finally, regulatory and legal issues surrounding cannabinoid therapy may also affect future translational research. While the results are encouraging, more studies are needed before these findings can be applied to patient treatment."