Guillermo Velasco and colleagues, at Complutense University, Spain, have provided evidence that suggests that cannabinoids such as the main active component of marijuana (THC) have anticancer effects on human brain cancer cells.
In the study, THC was found to induce the death of various human brain cancer cell lines and primary cultured human brain cancer cells by a process known as autophagy.
Consistent with the in vitro data, administration of THC to mice with human tumors decreased tumor growth and induced the tumor cells to undergo autophagy. As analysis of tumors from two patients with recurrent glioblastoma multiforme (a highly aggressive brain tumor) receiving intracranial THC administration showed signs of autophagy, the authors suggest that cannabinoid administration may provide a new approach to targeting human cancers.
From the NIH Hypothesis: cannabinoid therapy for the treatment of gliomas?
Confirmation of the hypothesis: Cannabinoid action induces autophagy-mediated cell death through stimulation of ER stress in human glioma cells
Autophagy can promote cell survival or cell death, but the molecular basis underlying its dual role in cancer remains obscure. Here we demonstrate that delta(9)-tetrahydrocannabinol (THC), the main active component of marijuana, induces human glioma cell death through stimulation of autophagy. Our data indicate that THC induced ceramide accumulation and eukaryotic translation initiation factor 2alpha (eIF2alpha) phosphorylation and thereby activated an ER stress response that promoted autophagy via tribbles homolog 3-dependent (TRB3-dependent) inhibition of the Akt/mammalian target of rapamycin complex 1 (mTORC1) axis. We also showed that autophagy is upstream of apoptosis in cannabinoid-induced human and mouse cancer cell death and that activation of this pathway was necessary for the antitumor action of cannabinoids in vivo. These findings describe a mechanism by which THC can promote the autophagic death of human and mouse cancer cells and provide evidence that cannabinoid administration may be an effective therapeutic strategy for targeting human cancers.
Full text of the report in pdf