Cannabinoids in Glioblastoma Therapy: New Applications for Old Drugs

Glioblastoma (GBM) is the most malignant brain tumor and one of the deadliest
types of solid cancer overall. Despite aggressive therapeutic approaches consisting of
maximum safe surgical resection and radio-chemotherapy, more than 95% of GBM
patients die within 5 years after diagnosis. Thus, there is still an urgent need to develop
novel therapeutic strategies against this disease. Accumulating evidence indicates that
cannabinoids have potent anti-tumor functions and might be used successfully in the
treatment of GBM. This review article summarizes the latest findings on the molecular
effects of cannabinoids on GBM, both in vitro and in (pre-) clinical studies in animal
models and patients. The therapeutic effect of cannabinoids is based on reduction
of tumor growth via inhibition of tumor proliferation and angiogenesis but also via
induction of tumor cell death. Additionally, cannabinoids were shown to inhibit the
invasiveness and the stem cell-like properties of GBM tumors. Recent phase II clinical
trials indicated positive results regarding the survival of GBM patients upon cannabinoid
treatment. Taken together these findings underline the importance of elucidating the
full pharmacological effectiveness and the molecular mechanisms of the cannabinoid
system in GBM pathophysiology.