Seventy phytocannabinoids are now known to be synthesized by Cannabis sativa (marijuana) [1]. The major non-psychoactive cannabinoid cannabidiol (CBD) exhibits antiproliferative effects against breast, cervix, colon, glioma, leukemia, ovary, prostate, and thyroid cancer cells [2]. In this study, we investigated the antiproliferative effect of CBD on the ME-180 cervical cancer cell line. The cells were plated at subconfluent density in DMEM-F12 medium containing 10% fetal bovine serum (FBS), and the experiments were carried out in the serum-free medium. CBD inhibited the proliferation of these cells with an IC50 value of approximately 6µM. At 10µM, CBD induced apoptosis of nearly all cells within 24 hours (figure below). However, within few hours of treatment with CBD, the cells also exhibited numerous cytoplasmic vacuoles, reminiscent of paraptosis. Significant reversal of the CBD-induced inhibition of proliferation was observed in the presence of antioxidant α-tocopherol (200µM), Trolox (200µM), peroxisome proliferator-activated receptor-γ antagonist GW9662 (2µM), and ceramidase inhibitor L-cycloserine (100µM). Limited reversal of inhibition of proliferation was also observed in the presence of 2µM of cannabinoid receptor (CB) antagonist AM251 (CB1). Nevertheless, the cytoplasmic vacuoles observed in the presence of CBD persisted in the presence of these compounds, with the exception of α-tocopherol and Trolox. The results of our study suggest that CBD exerts its antiproliferative effect via multiple mechanisms, and it could be a potential treatment for cervical cancer.
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