Expression and functional relevance of cannabinoid receptor 1 in Hodgkin lymphoma.

Background: Cannabinoid receptor 1 (CB1) is expressed in certain types of malignancies. An analysis of CB1 expression and function in Hodgkin lymphoma (HL), one of the most frequent lymphomas, was not performed to date. Design and Methods: We examined the distribution of CB1 protein in primary cases of HL. Using lymphoma derived cell lines, the role of CB1 signaling on cell survival was investigated. Results: A predominant expression of CB1 was found in Hodgkin-Reed-Sternberg cells in a vast majority of classical HL cases. The HL cell lines L428, L540 and KM-H2 showed strong CB1-abundance and displayed a dose-dependent decline of viability under CB1 inhibition with AM251. Further, application of AM251 led to decrease of constitutively active NFκB/p65, a crucial survival factor of HRS-cells, and was followed by elevation of apoptotic markers in HL cells. Conclusions: The present study identifies CB1 as a feature of HL, which might serve as a potential selective target in the treatment of Hodgkin lymphoma.