Overexpression of IL-6 by Gene Transfer Stimulates IL-8-mediated Invasiveness of KYSE170 Esophageal Carcinoma Cells

Interleukin-6 (IL-6) has been associated with disease progression and poor prognosis in esophageal carcinoma. The aim of this study was to investigate the possible influence of IL-6 on the biological activities of esophageal carcinoma cells in terms of invasiveness. The human esophageal carcinoma cell line, KYSE170, was transfected with a plasmid vector expressing IL-6, and a stable transfectant overexpressing IL-6 was established. Invasiveness was evaluated by an invasion assay and compared between IL-6 and control transfectants. The invasiveness of the IL-6 transfectant was significantly higher than that of the control transfectant, and was significantly reduced by IL-6-specific siRNA. In reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, IL-8 expression was significantly higher in the IL-6 transfectant than in the control transfectant, whereas the expression of Hepatocyte growth factor (HGF) and Vascular endothelial growth factor (VEGF) was not different. IL-8 expression in the IL-6 transfectant was significantly inhibited by IL-8-specific siRNA, whereas IL-6 expression was not. In addition, the invasiveness of the IL-6 transfectant was significantly reduced by IL-8-specific siRNA. These results indicate that the overexpression of IL-6 increases the invasiveness of KYSE170 esophageal carcinoma cells and IL-6-induced IL-8 plays a predominant role in increasing invasiveness.