Cannabinoids Halt Ovarian Cancer Growth via Cell Cycle Pathway

Researchers in Thailand have discovered that a combination of CBD and THC can effectively kill ovarian cancer cells and stop their growth while sparing healthy cells. A study published today in Frontiers in Pharmacology shows, for the first time, how both compounds act synergistically to regulate the PI3K/AKT/mTOR pathway, which is known to drive cancer growth and treatment resistance in ovarian cancer cells.

“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 Siyao Tong, PhD, researcher at the faculty of medicine of Khon Kaen University and lead author of the study. “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.”

Due to a lack of easily recognizable symptoms, ovarian cancer is notoriously hard to diagnose, meaning it is often discovered at later stages when it is more difficult to treat.  While targeted treatments such as PARP inhibitors have revolutionized treatment for a subset of ovarian cancer patients, new therapeutic approaches are needed to improve outcomes for a broader population, including those with treatment-resistant tumors. 

“Ovarian cancer remains one of the deadliest gynecological malignancies, characterized by late diagnosis, high recurrence rates, and limited effective treatment options,” said Tong. “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.”

Both CBD and THC have been previously shown to have antitumor effects in a variety of cancers, with research efforts currently evaluating their potential to improve outcomes as an add-on to chemotherapy courses. However, the effects of a CBD-THC combination and the mechanisms of action behind had not yet been explored. 

Tong and colleagues tested the effects of both cannabinoid compounds in two ovarian cancer cell lines, one of them sensitive to platinum-based chemotherapy drugs and another resistant to this form of treatment. Separately, both compounds stopped the growth of cancer cells in vitro, but combining them resulted in significantly improved outcomes, inducing cell death in a larger proportion of cancer cells when administered in a 1:1 ratio. The combination treatment was also successful at preventing cell migration, showing early promise for the prevention of metastases. 

The team then looked at the effects of CBD and THC on the PI3K/AKT/mTOR pathway, a cell cycle signaling pathway which is often deregulated in ovarian cancer. The combination of both compounds was found to reduce the phosphorylation of PI3K, AKT and mTOR while increasing the phosphorylation of PTEN, which restored the tumor-suppressing functions of this signaling pathway. 

Since minimal effects were seen on healthy ovarian cells, the treatment shows potential to be less toxic than drugs currently in use. However, more research will be needed to determine whether these compounds would be a safe and effective treatment for ovarian cancer patients. Future experiments will include in vivo and pharmacokinetic studies to determine the effects of the drug combination in the native context of ovarian cancer cells.