REGULATION OF INTERLEUKIN-8 MESSENGER-RNA EXPRESSION AND PROTEIN SECRETION IN A MELANOMA CELL-LINE BY TUMOR-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, rever se 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 Cole 38. Seeding of melanoma cells into culture dishes resulted in a significant increa se of IL-8 expression, which could be attributed to adherence. A prono unced increase of IL-8 mRNA expression and protein production was indu ced 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 effect o f IFN gamma on melanoma cells is in contrast to its stimulatory effect on melanocytes.