When it comes to treating ovarian cancer, existing drugs are often limited in effectiveness and can cause significant side effects, underscoring the need for new options. In response, researchers are exploring alternative drugs, including herbal-based strategies.

For instance, a research group from Khon Kaen University investigated the cannabis plant, which has been used to help relieve side effects of cancer treatments. Namely, they focused on the individual and combined effects of two cannabis compounds on human ovarian cancer cell lines: cannabidiol (CBD), which is non-psychoactive, and delta-9-tetrahydrocannabinol (THC), which is responsible for cannabis’s psychoactive effects and “high” feeling.

In a recent study, published in Frontiers in Pharmacology, the same research group demonstrated that a combination of CBD and THC successfully killed a large proportion of ovarian cancer cells while sparing healthy cells in vitro.¹ Their findings lay a foundation for alternative treatments.

First, the researchers assessed two ovarian cancer cell lines: one that is sensitive to platinum-derived drugs and another that is resistant. Platinum drugs are often used as initial ovarian cancer treatments. They treated these groups and healthy cells with different doses of CBD, THC, and ratios of CBD:THC.

Of these treatments, the CBD:THC combination at a one-to-one ratio had a synergistic effect, producing the best results: It led to in fewer and smaller cancer cell colonies, induced cell death, and decreased the cells’ ability to migrate. The researchers also noted that the treatment exhibited selective toxicity towards cancer cells, leaving healthy cells unharmed.

To better understand the mechanisms behind these anti-cancer effects, the researchers examined key cell signaling pathways. In ovarian cancer cells, the PI3K/AKT/mTOR signaling pathway is often hyperactivated, regulated by phosphorylation, and contributes to tumor development. When the team tested the CBD:THC combination on ovarian cancer cell lines, they observed reduced phosphorylation of proteins within the PI3K/AKT/mTOR pathway. They also detected an increase, or restoration, of a tumor-suppressor protein, which may further contribute to the dampened signaling activity.

“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 study coauthor Siyao Tong in a press release.