Coordinate modulation of melanogenesis and type I trimer collagen secretion by type I collagen substratum during reversible conversion between melanotic and amelanotic cells in mouse B16 melanoma.

Two clones, melanotic (M3) and amelanotic (A4) cells, were isolated from B16 mouse melanoma cells. The two clones exhibited distinct phenotypes in cell morphology, melanogenesis, and secretion of extracellular matrix, with preferential secretion of type I trimer collagen in A4 cells. Grown on type I collagen substratum, M3 cells were converted to cells exhibiting similar phenotypes to A4 cells. Subsequent culture of A4-like cells on plastic dishes resulted in the recovery of the initial M3 phenotypes. These results indicate that the reversible conversion between melanotic and amelanotic cells in B16 melanoma cells in vitro is controlled by type I collagen substratum and that modulation of cell shape, melanogenesis, and type I trimer collagen secretion during conversion were all coordinately and reversibly regulated. The results provide evidence that extracellular matrix can control the cell phenotypes in mouse B16 melanoma. Modulation of type I trimer collagen secretion by type I collagen substrate could be a useful model for studying the alpha 1(I) chain-specific regulatory mechanism.