Involvement of interleukin-6 in the biology and metastatic activity of B16F10 melanoma cells.

In previous studies, we demonstrated the presence of the interleukin-2 (IL-2) signalling system in B16F10 murine melanoma and observed that in vitro treatment of B16F10 cells with IL-2, enhanced metastasis. To further understand the role played by interleukins in melanoma, we examined the effect of IL-6 on the metastatic activity and properties of B16 melanoma cells. We observed that B16F10 cells, cultured in the presence of IL-6, showed a clear increase in their metastatic ability, both in the liver and in the lungs. Neither cell proliferation nor in vitro colony formation were affected by IL-6; however, the expression of CD44 and VLA-4 increased. The IL-6 gene was expressed in B16F10 cells as shown by RT-PCR. A slight induction of IL-6 mRNA expression by IL-2 was observed, but not after treatment with IL-1beta or IL-6. Nevertheless, no soluble IL-6 could be detected in cell supernatants even after treatment with IL-2. Finally, we tested the effect of IL-1beta, IL-6 and IL-2 on the expression of the IL-2 receptor (IL-2R). IL-1beta turned out to be the strongest inducer of IL-2R expression in B16F10 cells. Altogether, these data confirm the involvement of interleukins in the biology and metastatic activity of melanoma.