Influence of interleukin-6 on the invasiveness of human colorectal carcinoma.

BACKGROUND Plasma interleukin-6 (IL-6) level correlates with patient survival in colorectal carcinoma and is regarded as a prognostic factor. In this study, the role of IL-6 in colorectal carcinoma proliferation, chemotaxis and invasion was investigated. MATERIALS AND METHODS Proliferation and invasion were measured in four colorectal carcinoma cell lines. The effect of IL-6 (10, 50, 100 ng/ml) on progression (the ability to grow, adhere, chemotax and invade) was also measured. RESULTS Physiological (10 ng/ml) and pharmacological (50 and 100 ng/ml) concentrations of IL-6 did not significantly affect growth. However, IL-6 (10 ng/ml) significantly increased attachment to basement membrane (p < 0.05). IL-6 (50 ng/ml) significantly increased the chemotaxis, anchorage-independent growth and invasiveness of SW-480 (one of the four cell lines) (p < 0.05). IL-6 (100 ng/ml) resulted in negative feedback inhibition of these effects. CONCLUSION IL-6 plays an important role in the progression of colorectal carcinoma.