Bortezomib inhibits bone marrow-derived dendritic cells.

Graft versus-host disease (GVHD) severely limits the application of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in treating leukemia. Dendritic cells (DCs) are critical for the development. Here, we examined the effect of proteasome inhibitor Bortezomib on DCs in vitro. Primary cultured mouse DCs were treated with Bortezomib and their proliferation was observed. The expression of CD80 and CD86 and cytokine secretion of LPS-activated DCs was also quantified under Bortezomib. The ability of DCs to activate T cells was also measured by the mixed lymphocyte reaction assay. Finally the effect of Bortezomib on nuclear translocation of NF-κB was measured by EMSA. Bortezomib can inhibit the proliferation of DCs in a dose- and time-dependent manner. It also blocked the expression of co-receptors CD80 and CD86 and secretion of cytokines IL-12 and TNF-α in DCs treated with LPS. Mixed lymphocyte reaction assay suggested Bortezomib reduced the ability of DCs to activate T cells. Finally, we found Bortezomib can inhibit the nuclear translocation of NF-κB in DCs. Our findings indicated that Bortezomib blocked the functions of DCs in various aspects, and is a potential drug candidate for GVHD.