Efeito antitumoral do canabidiol em carcinoma de células escamosas da cavidade oral e sua interação com a radiação ionizante

Abstract

Over 90% of oral cavity malignancies are oral squamous cell carcinomas (OSCC), whose traditional treatment comprises surgery, radio- and chemotherapy, depending on the cancer stage. Cannabidiol (CBD) is one of the main Cannabis sativa constituents. This compound has been investigated for treatment of many diseases, including cancer. Antitumor effects of CBD comprise autophagy, apoptosis, inhibition of cell proliferation, and reduction of metastasis. This study aimed to explore antitumor effects of CBD against OSCC and its interaction with ionizing radiation. We investigated the viability of OSCC cells (HN30) after treatment with CBD (5, 10, 15, 20, 25, 30 and 35 μM) through the MTT [3- (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. To further analyze the CBD antitumor potential, we performed long-term colony formation assays and assessed whether CBD (5, 15, 25 and 35 μM) would be able of interfering with the clonogenic ability of HN30 cell line. We also evaluated whether CBD (5, 15, 25 and 35 μM) exposure would interact with ionizing radiation (4 Gy). After a 24-h exposure period, CBD decreased HN30 cells viability in a concentration-dependent manner at 20, 25, 30 and 35 μM. The clonogenic potential of HN30 cells was also significantly reduced at 25 and 35 μM. Cell cultures treated with ionizing radiation followed by exposure to CBD for 24 h had their clonogenic ability significantly reduced in relation to control, however, there was no significance when the groups treated with the association of therapies were compared to the group treated with radiation alone. Conclusion: CBD exerts antitumor effects on OSCC cells; nevertheless, it does not have synergistic action when associated with ionizing radiation in vitro.