Cannabidiol Regulates CD47 Expression and Apoptosis in Jurkat Leukemic Cells Dependent upon VDAC-1 Oligomerization.

Cannabidiol (CBD) is a major non-psychoactive phytocannabinoid that exerts multiple biological effects in the body. It has been shown to exert anti-cancer effects in a variety of cancer cells, including acute lymphoblastic leukemia of pre-T cell origin (T-ALL), a highly aggressive hematological malignancy. However, the mechanisms underlying CBD's anti-cancer effects are not fully understood. Furthermore, cancer cells abundantly express surface CD47, which is a negative regulator of phagocytosis and linked with cell survival/death. Little is known about CBD effects on the expression of CD47 in T-ALL cells. The objectives of this study were to address these issues. Studies were conducted in vitro using Jurkat cells and human peripheral blood mononuclear cells in different culture conditions, CBD concentrations, and in the presence or absence of different reagents. CBD downregulates CD47 expression and induces apoptosis in Jurkat cells. Similar biological effects of CBD were also observed in primary human CD4 T cells, albeit at reduced levels. The CBD's effects on CD47 expression and apoptosis were not rescued by a cannabinoid receptor (CBR)-2 agonist, a CBR-2 antagonist, or an anion channel blocker. However, these effects on CD47 expression and apoptosis were significantly rescued by a Voltage-Dependent Anion Channel (VDAC)-1 oligomerization inhibitor. Overall, we conclude that CBD downregulates CD47 expression and induces apoptosis involving VDAC-1 oligomerization. Furthermore, they also suggest that CBD's pro-apoptotic effects on primary human T cells should also be monitored if it is used as an anti-cancer adjuvant or neo-adjuvant therapeutic in cancer patients.