Cannabidiol Enhances the Inhibitory Effects of Δ9-Tetrahydrocannabinol on Human Glioblastoma Cell Proliferation and Survival

This study sought to determine if Cannabidiol (CBD; non-psychoactive cannabinoid) increases the effects of Delta-9-Tetrahydracannabinol (Δ9-THC or THC) of stopping human glioblastoma cell growth. This study was also interested in determining if CBD would help THC inhibit cancer malignancy (spreading/growth). Finally, these researchs sought to determine if the combination of CBD and Δ9-THC created cancer cell apoptosis greater than the effects of Δ9-THC alone.

Previous research has determined that THC has an effect of creating apoptosis (natural programmed cell death) for various cancer cells. 

Glioblastoma is a highly invasive, malignant type of brain tumor in the glial tissue (glia are commonly known as the 'glue' of the nervous system) of the central nervous system.  In addition to uncontrolled cell growth, aggressive types of glioblastoma cells have a tendency to migrate away from the primary tumor of origin and invade neighboring central nervous system tissue.     

This was an in vitro study (taking place in a test tube, Petri dish), and all cancer cell types were grown and tested in a Petri dish of a controlled environment. 

  • To measure the effects of CBD and THC of cancer cell growth and invasiveness all Petri dish samples received compounds (THC, CBD, or a combination) for 2 days. On the 3rd day of the study all grown cancer cells went through various chemical analyses to determine the effects of compounds on cancer cell growth and spreading. 
  • To measure apoptosis cancer cells were grown in culture dishes and treated with the appropriate compounds (THC, CBD, or a combination) every 24 hours for 3 days.  On the 2nd and 3rd days these culture dishes went through analysis to determine levels of apoptosis.

The results show that both THC and CBD had independent effects on stopping glioblastoma cell growth.  Also, CBD increased/enhanced the ability of THC to stop glioblastoma cell growth, but did not have a direct effect on natural programmed cell death. THC was also able to inhibit glioblastoma cell spreading.  Finally, there was a minor increase in apoptosis produced with THC, but it was not found to be significantly different from the control (no drug application). However, when THC and CBD were combined, increase in apoptosis was observed.  Results showed a small increase in apoptosis with the combination treatment (THC and CBD) after two days, and a strong induction of apoptosis by day 3.  

In conclusion, the combination of THC and CBD have a greater effect of reducing glioblastoma cell growth and natural programmed cell death when used together.  Only THC seems to have an effect of reducing cancer cell spreading.

Article Authors:  Jahan P. Marcu, Rigel T. Christian, Darryl Lau, Anne J. Zielinski, Maxx P. Horowitz,  Jasmine Lee, Arash Pakdel,  Juanita Allison, Chandani Limbad,  Dan H. Moore, Garret L. Yount, Pierre-Yves Desprez and Sean D. McAllister

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