Effects of interferons and cytokines on melanoma cells

This review summarizes recent information on the effects of immunomodulatory cytokines on human melanoma cells. The action of interferon (IFN)-alpha, -beta, and -gamma has been extensively examined in melanoma and melanocyte cultures in vitro, and increasing information on the action of other cytokines is now available. All IFNs revealed a dose-dependent antiproliferative effect on melanoma cells with the highest growth inhibition caused by IFN-beta. Proliferation was also inhibited by interleukin (IL) 1-alpha and -beta, and tumor necrosis factor (TNF)-alpha. For IL-4, both growth-stimulatory and -inhibitory properties have been reported. Cellular differentiation in terms of melanin synthesis, formation of dendritelike structures, and antigenic changes was not affected by IFN-alpha or -beta. IFN-gamma, however, induced a more dedifferentiated and biologically more aggressive phenotype of melanoma cells. Histocompatibility antigen (HLA) class I molecules were found upregulated by all IFNs and by TNF-alpha, associated with a marked increase of melanoma cell lysis by tumor infiltrating lymphocytes in vitro. HLA class II molecules were de novo expressed or enhanced by IFN-gamma and TNF-alpha. The adhesion molecules ICAM-1, LFA-3, and VLA-2 were upregulated by IFN-gamma, TNF-alpha, and IL-1-beta, whereas melanoma-associated antigens were hardly affected by cytokines. It seems that both antiproliferative and immunomodulatory effects may contribute to the antitumoral activity of cytokines in vivo. In vivo application of cytokines as well as combinations with cytotoxic drugs, therefore, may be promising for future treatment strategies.