Effect of IL-2 and IL-6 on parameters related to metastatic activity in a murine melanoma

Previous results have shown that the metastatic colonization with B16F10 melanoma in vivo increased after in vitro treatment of the cells with IL-2 or IL-6. To further investigate the mechanisms underlying this effect, we have studied adhesion, invasion, and proliferation properties of B16 melanoma, using two sublines with different metastatic ability. Adhesion of tumor cells to Matrigel coats increased using IL-6, which also induced upregulation of VLA-4 expression in both sublines. Unexpectedly, invasion through Matrigel filters was almost completely inhibited by IL-6 and decreased in the presence of IL-2. Cell growth was not affected by these interleukins; however, IL-6 could partially overcome the proliferation blockade induced by stress conditions. Taken together, these results suggest that upregulation of adhesion properties and/or the protective effect induced by IL-6 could account for the enhancement of metastasis exerted by this interleukin.