Glioblastoma: How Can Cannabis Help Against One of the Most Aggressive Cancers?

By João R. Negromonte

Considered a devastating type of brain cancer that grows rapidly and invades brain tissues, glioblastoma mainly affects adults, with an average survival rate of 15 to 18 months. According to the National Cancer Institute (INCA), only 5% of patients survive up to 5 years after diagnosis. Due to this grim analysis, doctors and researchers agree that there is a need for a cure, or at the very least, a more effective treatment for the disease.  

Currently, a study conducted by researchers at the University of Birmingham in the United Kingdom is examining the potential effects of cannabinoids in treating glioblastoma. Named Aristocrat, the research brings together patients with the disease to investigate whether the combination of cannabis compounds with traditional chemotherapies actually yields positive results.

Glioblastoma begins in star-shaped glial cells called astrocytes. In healthy tissues, astrocytes play important roles in the formation and regulation of synapses between neurons. However, due to their importance, malfunctioning astrocytes can cause major problems.

In patients with glioblastoma, cancerous astrocytes form a rapidly growing tumor. Current treatment for glioblastoma involves surgery followed by radiation therapy and chemotherapy. Even with treatment, the tumor regrows in 95% of patients.

How Does Traditional Therapy Combined with Cannabinoids Help?

A team of researchers led by Professor Susan Short from the University of Leeds in England is investigating the anticancer potential of cannabinoids such as THC and CBD. Specifically, they want to know if the combination of marijuana plant compounds and the chemotherapy drug Temozolomide is more effective in treating glioblastoma than the drug alone.

Although Temozolomide is a potent therapy on its own, a current limitation of glioblastoma treatment is resistance to the compound. Over time, cancer cells become less sensitive to chemotherapy, allowing the tumor to regrow. Therefore, to improve patient outcomes, this limitation must be overcome. Previous experiments have shown that cannabinoids had anticancer effects, so Susan and her team are exploring whether a combined therapy could eliminate this obstacle.

Promising Results 

As doctors and scientists have learned more about glioblastoma, they have noticed an interesting trend. More severe cases of the disease have been characterized by an increased expression of the CB2 receptor in cancer cells. This abnormal expression of cannabinoid receptors in cancerous tissue suggested a potential therapy: cannabinoids.

Initial investigations then suggested they were on the right track. Through in vitro experiments using cultured glioblastoma cells, scientists found that treatment with THC led to a reduction in tumor size. Other experiments revealed that the psychoactive component of cannabis intervenes in the anticancer effects, activating pathways in cancer cells, leading them to self-destruct.

It is important to note that the same experiments were conducted on healthy cells, and the same effect was not observed. That is, THC was able to selectively kill cancer cells without harming healthy tissue. Other experiments also showed that THC can slow tumor growth by preventing cancer cells from dividing and inhibiting the formation of blood vessels that feed them. 

As for CBD, although it has low affinity, according to researchers, for receptors such as TRPV1, TRPV2, 5HT-1A, and GPR55, it works synergistically with THC, aiding in this tumor reduction.

More tests are still needed to prove that cannabis compounds can indeed be an adjuvant in glioblastoma treatment; however, tests and research like this reinforce the importance of closely observing cannabinoid medicine.