Alteration of tumor phenotypes of B16 melanoma after genetic remodeling ofthe ganglioside profile

Gangliosides have been thought to be tumor markers of various neuroectoderm -derived cancers. However, their roles in malignant phenotypes of cancer ce lls are not well understood. We have performed the remodeling of gangliosid e profiles of mouse melanoma B16 (B78 subline) by introducing GM2/GD2 synth ase cDNA, and analyzed the phenotypic changes such as cell morphology, grow th, adhesion and c-fos gene expression. Although newly expressed GM2 was cl early detected, GM2-positive transfectant cells showed rather reduced growt h rates in vivo and in vitro, lower expression levels of c-fos gene and inc reased levels of cell adhesion to extracellular matrices compared to contro l cells, These results suggested that GM2 is involved in the regulation of cell-cell or cell-extracellular matrix interaction, and negatively control cell proliferation.