Tumour-associated macrophages secrete IL-6 and MCP-1 in head and neck squamous cell carcinoma tissue

Conclusion. Tumour-associated macrophages (TAMs) in head and neck squamous cell carcinomas (HNSCCs) secrete interleukin 6 (IL-6) and monocyte chemotactic protein (MCP-1) that can be down-regulated by L-leucine-methylester (LLME); however, there is no qualitative difference between function of TAMs and tissue macrophages in mucosa as measured by IL-6 and MCP-1 secretion. Objectives. TAMs play an important role in the interaction with tumour cells in malignant tumours. The cells in the tumours that are the main sources of the various signal substances need to be further elucidated. The aim of this investigation was to reveal whether TAMs in HNSCCs secrete IL-6 and MCP-1. These cytokines influence tumour cell growth and macrophage influx in tumours, respectively. Materials and methods. In order to inhibit macrophage function in F-spheroids, in some experiments the tissue fragments were initially incubated with LLME, a substance that selectively inhibits function of phagocytes. IL-6 and MCP-1 secretion from untreated F-spheroids was compared to cytokine secretion from LLME-treated F-spheroids as measured by ELISA. Results. LLME did not affect the viability of F-spheroids and reduced IL-6 and MCP-1 secretion from monocyte-derived macrophages in vitro. F-spheroids from LLME-treated tissue fragments showed lower IL-6 and MCP-1 secretion compared with F-spheroids from tissue fragment untreated with LLME.