Sorafenib but not sunitinib affects the induction of immune responses

3504 Background: The tyrosine kinase inhibitors (TKIs) sorafenib and sunitinib are approved for the treatment of patients with metastatic renal cell cancer. To analyze the possible use of these compounds in combination with immunotherapeutic approaches we investigated the effects of both TKIs on function of human dendritic cells (DCs) and induction of primary immune responses in vitro and in vivo. Methods: Human monocytes-derived DCs were treated with DMSO, sorafenib or sunitinib. Functional and phenotypic analyses as well as the possible impact on signal transduction pathways were performed. Furthermore, induction of immune responses in vivo was analyzed in animals treated with both compounds. Results: Sorafenib but not sunitinib inhibits function of DCs. Exposure of DCs to sorafenib reduces expression of CD1a, MHC and costimulatory molecules in response to stimuli via TLR ligands. Sorafenib reduces cytokine production by DCs as well as their ability to migrate and stimulate T cell (TC) responses. We fou...