Regulation of interleukin-8 mRNA expression and protein secretion in a melanoma cell line by tumour necrosis factor-alpha and interferon-gamma.

Interleukin-8 (IL-8) is a cytokine that is thought to promote melanoma tumour progression. We evaluated and adapted a non-radioactive, reverse transcriptase-polymerase chain reaction method for semiquantitative analysis of IL-8 mRNA expression. Using this technique we studied the regulation of IL-8 levels in the melanoma cell line Colo 38. Seeding of melanoma cells into culture dishes resulted in a significant increase of IL-8 expression, which could be attributed to adherence. A pronounced increase of IL-8 mRNA expression and protein production was induced by tumour necrosis factor-alpha (TNF alpha). Interferon-gamma (IFN gamma) partially inhibited TNF alpha-induced IL-8 secretion, whereas no influence on IL-8 mRNA levels was detected. The inhibitory affect of IFN gamma on melanoma cells is in contrast to its stimulatory effect on melanocytes.