MELANOGENESIS, BIOSYNTHETIC PHENOTYPE OF FIBRONECTIN AND COLLAGEN, AND MIGRATING ACTIVITY IN CLONED B16 MOUSE MELANOMA-CELLS

Three clones, melanotic (M3), amelanotic (A4 and A7) cells were isolat ed from B16 F10 mouse;melanoma cell line. These clones exhibited diffe rent biosynthetic activities of fibronectin and collagen: A4 clone sho wed relatively active synthesis of both collagen and fibronectin, and A7 clone exhibited most active fibronectin synthesis, whereas no signi ficant synthesis of these molecules was observed in M3 clone. No signi ficant difference in growth rate was observed in these three clones. M igrating activities measured by basement membrane matrix-coated dishes :were greater in A7 clone than in A4 and M3 clones. Messenger RNA leve ls of collagen and fibronectin paralleled collagen and fibronectin syn thesis in these clones whereas tyrosinase mRNA level was unaltered bet ween melanotic (M3) and amelanotic (A4 and A7) cells. These results in dicate that B16 melanoma cells have heterogeneous cell populations con sisting of different biosynthetic and metastatic properties. These clo nes may provide good tools for studying the relationship between the p henotypes of melanogenesis biosynthesis of extracellular macromolecule s and migrating activity of melanoma cells.