Effect of Exogenous Cannabinoids on Non-Hodgkin Lymphoma

Saba Omer¹, Mohammed Mansour¹, Satyanarayana Pondugula^1, Sindhu Ramesh³, Muralikrishnan Dhanasekaran⁴, Brad Matz², Dawn Boothe¹

¹ Department of Anatomy, Physiology, & Pharmacology, ²Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA

³Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, Alabama, USA

Abstract

Non-Hodgkin’s lymphoma is the fifth leading cause of human cancer death, and one of the most commonly encountered neoplasms in canine. Approximately 30% of human and 95% of canine lymphoma tumors develop chemotherapy resistance, hence, novel strategies that might be effective against therapy-resistant lymphoma are needed for both species. Canine lymphoma shows striking similarities to human Non-Hodgkin’s lymphoma (NHL), in cancer biology, histology, and gene expression, which makes canine the best model to study novel treatment of lymphoma for both species. The anti-cancer effects of cannabinoids (CB) have been studied extensively in the last two decades with evidence of potential efficacy demonstrated using various models of human cancer. The purpose of this study was to demonstrate and to compare, for the first time the anticancer effects of phytocannabinoids, and synthetic cannabinoids, in canine and human lymphoma cell lines. We have used malignant canine B cell type (1771 and CLBL1) and T cell type (CL1) NHL cell lines, canine PBMCs and, human B cell type NHL cell line (RAMOS). All cell lines were cultured in RPMI and treated with all cannabinoids individually at concentrations from 100 nM to 50µM for 24 and 48 hours. Canine PBMCs and vehicle were used as a control. Cell viability was assessed using MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5 Diphenyltetrazolium Bromide) cell proliferation assay and oxidative stress, mitochondrial, inflammatory, and apoptotic markers of cell death were assessed using spectrophotometric and fluorometric analysis.  Data were analyzed using one-way ANOVA (Prism®) and SAS.  Our results demonstrate a significant dose-dependent decrease in cancer viability with both phyto and synthetic cannabinoids in canine and human lymphoma cell lines. However, the phytocannabinoid THC did not show a significant cytotoxic effect on canine CL1 (T cell type NHL) cell viability. Overall, the phytocannabinoid CBD were found to be the most potent exogenous cannabinoids (based on their IC50 values) of those studied. Our results of biochemical analysis also revealed increase in oxidative stress, inflammation, and apoptotic markers in cells treated with exogenous cannabinoids. Together, our results suggest that therapies using phytocannabinoids and synthetic cannabinoids might have efficacy in reducing tumor burden in malignant NHL.

Acknowledgements

We are thankful to Dr. Steven Suter for sharing Canine lymphoma cell lines with us. We are thankful to the following students for helping us with biochemical analysis Suhrud Pathak, Dylan Bowen and Rishi Nadar.

Keywords

Lymphoma, Cannabinoid, Cancer