The Role of Cm1 on Increase of Prostaglandin E2 Production From Human Burkitt's Lymphoma

Abstract

CM1 (centrocyte/‐blast marker 1) is originally defined as a germinal center (GC) B cell marker and it plays a critical role on B cell development in GC. In addition, CM1 is expressed on Burkitt's lymphoma cell lines. It suggests that CM1 plays a role in the pathogenesis of tumor cells. Cyclooxygenase‐2 (COX‐2) and its product, prostaglandin E2 (PGE2) are well‐known molecules, which are closely related with the pathogenesis of several kinds of tumor. Therefore, we investigated the role of CM1 on the regulation of COX‐2 expression and PGE2 production from Burkitt's lymphoma cell lines, such as Raji and Ramos. When CM1 was ligated with anti CM1 mAb, PGE2 production was increased and CM1‐induced PGE2 production was inhibited by the pre‐treatment of NS‐398, COX‐2 specific inhibitor and kamebakaurin, specific inhibitor of NF‐kB. Finally, the effect of increased PGE2 production by CM1 ligation on activation induced cytidine deaminase (AID) was evaluated. The expression of AID was increased by CM1 ligation and it was suppressed by the pre‐treatment of NS‐398 and kamebakaurin. Taken together, CM1‐induced PGE2 production increases the expression of AID via the activation of NF‐kB and increase of enzymatic activity of COX‐2.