Neutrophil Interactions With Sialyl Lewis X on Human Nonsmall Cell Lung Carcinoma Cells Regulate Invasive Behavior

BACKGROUND: The carbohydrate sialyl Lewis X (sLeX) is expressed on leukocytes and carcinoma cells and binds to selectins during inflammatory processes and early metastasis. Synthesis of sLeX depends on activity of enzymes, including a(1,3/1,4) fucosyltransferase (FucT-III). Tumor necrosis factor-alpha (TNF-alpha) up-regulates FucT-III, resulting in increased sLeX in the airways of patients with respiratory disease; however, the mechanisms that regulate sLeX in the inflammatory tumor microenvironment are not well understood. METHODS: The authors stably transfected human lung carcinoma cell lines with the FucT-III gene and exposed them to TNF-alpha to investigate its role in regulation of sLeX expression and selectin-binding ability using semiquantitative real-time polymerase chain reaction and flow cytometry. Cytokine expression was examined in transfected cells using chemiluminescent arrays and enzyme-linked immunosorbent assays, and invasion was studied using Matrigel assays and alterations in morphology. Human lung tissue arrays were analyzed for immunohistochemical detection of sLeX and neutrophils. RESULTS: Stimulation of FucT-III-transfected cells with recombinant human (rh) TNF-alpha up-regulated sLeX expression and increased E-selectin binding. Transfected cells secreted high levels of interleukin 8, growth-regulated oncogene-alpha, and mast cell proteinase-1. Cells exposed to rhTNF-alpha, neutrophil-conditioned media, and cultures with a 5: 1 ratio of neutrophils to cancer cells had significantly increased sLeX expression and invasiveness and underwent nonadherent morphologic changes. In lung carcinomas, but not in normal lung tissues, 71% of tumors were highly positive for sLeX expression in areas of increased neutrophil infiltration. CONCLUSIONS: The current results indicated that neutrophils may be recruited to areas of FucT-III activity and sLeX expression in lung carcinomas to enhance the invasive and metastatic potential of lung cancer cells. Cancer 2011; 117: 4493-505. (C) 2011 American Cancer Society.