The effect of TGF-β1 on cell proliferation and proteoglycan production in human melanoma cells depends on the degree of cell differentiation

The effect of transforming growth factor β1 (TGF-β1) on cell proliferation, colony formation in soft agar and synthesis and structure of proteoglycans was studied in three human melanoma cell lines at different stages of differentiation: SK-mel-1.36-1-5 (early), SK-mel-3.44 (intermediate) and SK-mel-23 (late). TGF-β1 potently inhibited cell growth in monolayer as well as in soft agar. TGF-β1 increased the release of sulfated proteoglycans into the medium, including the cell-specific melanoma proteoglycan, mel-PG, and induced changes in disaccharide composition and sulfation of the glycosaminoglycan chains. In all the cases, the effect of TGF-β1 was more pronounced in the most undifferentiated cell line SK-mel-1.36-1-5 than in the SK-mel-3.44, whereas it had no effect on the most differentiated SK-mel-23 cells.