Abstract 1395: CD16+ dendritic cells (DC) promote squamous carcinoma cell (SCC) survival, and SCC affect DC phenotype and migration

Abstract In the inflammatory mucosal microenvironment of head and neck squamous cell carcinoma (HNSCC), dendritic cells (DC) are prominent; they express CD16, and are usually in direct contact with tumor cells. Mucosal and inflammation-associated DC develop from monocytes, and monocyte-derived DC are used in HNSCC immunotherapy. However, beyond apoptotic tumor cell uptake and presentation of tumor antigens by DC, HNSCC cell interactions with DC are poorly understood. Using co-cultures of monocyte-derived DC and established HNSCC cell lines we found that carcinoma cells induced significant increases in CD16 expression on DC while promoting a CD1a+CD86dim immature phenotype, similar to that observed in HNSCC specimens. Moreover, HNSCC cells strongly affected DC migration, both steady-state and CCL21-induced. The effects of carcinoma cells on migration were donor-dependent, and CCL21-induced migration directly correlated with HNSCC-mediated effects on CCR7 and CD38 expression on DC. Most remarkably, the numbers of live detached HNSCC cells were orders of magnitude higher in DC-HNSCC co-cultures than in parallel HNSCC cell cultures without DC. This study provides a novel insight into the outcomes of DC-HNSCC interactions relevant to the tumor microenvironment. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1395. doi:10.1158/1538-7445.AM2011-1395