O107 Tumor-Specific CD4CD8ab T Cells Infiltrating Human Colorectal Tumors Murielle Corvaisier1, Guillaume Sarrabayrouse 1 , Laure-Hélène Ouisse1, Céline Bossard1, Bernard Le Mével2, Elisabeth Diez1, Lucien Potiron3, Nadine Gervois1, Agnès Moreau-Aubry1, Francine Jotereau1 1 INSERM U892, Nantes, France, 2 Centre Régional de lutte contre le cancer, Nantes, France, 3 Service de Chirurgie digestive, Clinique Jules Verne, Nantes, France Despite the demonstration that high T cell infiltration of Colorectal tumors (CRC) is of good prognosis, few is known about the tumor reactivity

of CRC infiltrating lymphocytes selleck screening library (TIL). The presence in CRC, and phenotype of tumor reactive TIL was addressed. We obtained ex-vivo TIL and TIL lines, by enzymatic digestion or culture respectively, from primary, and metastatic CRC samples (n = 4), and tumor cell lines selleck inhibitor from four of these. TIL reactivity to tumor cells was analyzed by intracellular cytokine secretion. In two patients tumor-reactive T cells were detected among a subset of TCRab CD8ab+CD4+ double positive (DP) TIL. Using a DP TIL clone tumor reactivity was shown to be HLA-A2 restricted

and directed against a large panel of carcinoma but not EBV-B or normal-cell lines. We then documented the presence of DP T cells in human CRC and healthy colon mucosa, and showed that these cells produced higher levels of IL-4 and IL-13 than CD4+ or CD8+ SP T cells. These findings demonstrate the presence of DP T cells in human normal

colon mucosa and colonic tumor samples, and show a major contribution of this subset to CRC TIL reactivity. Their high capacity to secrete IL-4 and Il-13 suggests that colon DP T cells are likely involved in colonic mucosa homeostasis and in the immunity to human CRC. O108 The Signaling Pathway PAR1-PAFR-MUC18 Links Inflammation with Melanoma Metastasis Vladislava O. Melnikova 1 , Gabriel J. Villares1, Andrey S. Dobroff1, Maya Zigler1, Krishnakumar Balasubramaniam1, Hua Wang1, Victor Prieto1, Menashe Bar-Eli1 1 Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA The cellular and molecular pathways that regulate platelet activation, blood coagulation, and inflammation are emerging as critical players in cancer progression and metastasis. We previously demonstrated find more that the pro-inflammatory Protease-Activated Receptor a (PAR1, thrombin receptor) is overexpressed in metastatic melanoma, where it modulates the expression of IL-8, MMP-2, VEGF, PDGF, and integrins. Most recently, we demonstrated that antagonists of the pro-inflammatory Platelet-Activating Factor receptor (PAFR) abrogate experimental human melanoma lung metastasis. We found that PAF activates p38 MAPK/CREB-mediated expression of MMP2 and MT1-MMP. Here, we demonstrate that in metastatic melanoma cells, PAR1 and PAFR are constitutively active, linked together and regulate gene expression.