Avogadro, Novara, Adriamycin price Italy, 3 University of Milan, Milano, Italy Tumor growth is supported by tumor stroma, which is made by matrix and infiltrating cells, such as tumor associated macrophages (TAM) and tumor associated dendritic cells (TADC). We have

recently reported that TAM display massive nuclear localization of the p50 NF-kB inhibitory homodimer, which correlates with impaired inflammatory functions. The functional significance of this observation was demonstrated in p50 NF-kB deficient mice, which displayed tumor growth inhibition. More recently, in order to evaluate whether this tolerogenic mechanisms may target other compartments of the immune system, we characterized the role of p50 NF-kB in dendritic cell (DC) functions, during their differentiation and maturation. Our data clearly show that p50 NF-kB plays a non redundant role in DC survival and APC functions. p50 NF-kB has pro-apoptotic functions in bone marrow derived DC, as its absence leads to a reduced rate of apoptosis/necrosis

in DC activated for 48 h with LPS. Moreover, LPS-matured p50 -/- DC display higher expression of MHC molecules, as well as higher secretion of pro-inflammatory cytokines such as IL-1b, TNF-a and IL-18. This correlates with the enhanced capability of p50-/- DC to activate T cell responses, in vitro and in vivo. Therefore, our data suggest that targeting p50 NF-kB activity may represent a strategy to enhance selective functions of DC, with potential application check details in anti-tumour vaccination strategies. O47 JAM-B and JAM-C: Ying and Yang of Metastasis and Anti-Tumor Immune Response Marie-Laure Arcangeli 1 , Vincent Frontera1, Florence Bardin1, Elodie

Obrados1, Ralph H. Adams2, Michel Aurrand-Lions1 1 Université de la Mediterrannée, Institut Paoli-Calmettes, CRCM INSERM U891, Marseille, France, 2 Department Tissue Morphogenesis, Max-Planck-Institute for Molecular Biomedicine, munster, Germany The adhesion molecules JamB and JamC belong to the Ig superfamily and have been shown to interact together. Through its expression on endothelial cells, JamC has been involved in the regulation of immune response, tumor growth and inflammation as demonstrated this website by several studies using blocking antibodies and transgenic mice1 2 3. Recently, high expression of JamC on fibrosarcoma has been correlated with increased metastatic potential of tumor cells. Whether this result simply reflects the adhesive property of JamC with JamB on endothelial cells or is due to a more complex regulation of inflammation and anti-tumor immune response remains to be established. Using B16F10 melanoma cells, which express JamC but not JamB, we show that silencing JamC in tumor cells inhibits proliferation, but that JAK assay subcutaneous growth of B16F10 tumor is not affected in JamB−/− mice suggesting that JamC controls cell proliferation independently of JamB engagement.