Interleukin-8 expression by head and neck squamous cell carcinoma

Abstract

Objective: To test the hypothesis that interleukin-8 (IL-8) is produced by human head and neck squamous cell carcinomas (HNSCCAs) and may therefore be a possible mediator for lymphocyte recruitment and neovascularization by these tumors.

Methods: Nine fresh samples of HNSCCA were analyzed for expression of IL-8 antigen using radioimmunoassay and immunohistochemical staining techniques. Also, four short-term primary cultures of HNSCCA and two continuous HNSCCA cell lines were then analyzed for production of IL-8 expression under both baseline conditions and following stimulation with other cytokines.

Results: The IL-8 antigen was detected in all fresh tumor homogenates by radioimmunoassay (5.58 to 331.69 ng of IL-8 per gram of tissue), and immunohistochemical results localized staining predominantly within the tumor cells. Primary cultures of HNSCCA and continuous HNSCCA cell lines produced only low levels of IL-8 (0.04 to 4.49 ng of IL-8 per 10(6) cells) under baseline (unstimulated) conditions. Stimulation of both primary cultures and cell lines with interleukin-1 and tumor necrosis factor induced significant increases in IL-8 antigen, while other cytokines failed to induce a significant increase.

Conclusions: This study demonstrates that IL-8 antigen is expressed by HNSCCA in vivo, and that cultured HNSCCA in vitro can be stimulated to express IL-8 antigen by both interleukin-1 and tumor necrosis factor. Local production of IL-8 by HNSCCA cells, and its regulation by other cytokines, may be important in both the lymphocyte recruitment and tumor neovascularization seen in HNSCCA, and may thus ultimately affect the natural history of the disease.