CYTOKINE AND GROWTH FACTOR MODULATION OF CELL CYCLE EVENTS IN HUMAN MELANOMA CELL LINES

Cytokines influence cell cycle events, which in some but not all instances can be associated with melanoma progression. Analysis of the G0/G 1 and S phase fractions of the cell cycle was used to assay the proliferative or inhibitory activity of cytokines against ten human melanoma cell lines, including pairs of cell lines derived from primary and metastatic tissue of individual patients. Cytokines and growth factors were generally capable of inducing either a proliferative or an inhibitory effect, depending upon the melanoma cell line tested. Distinct differences in responsiveness between the primary and metastatic partners of related pairs of melanoma cell lines was observed for IL-l β, IL-6, TNFα, TGFβ2, IFNα, IFNyand IGF-2. This data is complementary to previous works1.2 showing IL-6 and TGFβ2 to be inhibitory to.cell lines derived from early, but not advanced-stage melanomas. These alterations in cell cycle events were coincidental with a reduced expression of lCAM-1 and/or MHC antigen expression in response to some of these cytokines.