Ectopic expression of carcinoembryonic antigen by a melanoma cell leads to changes in the transcription of two additional cell adhesion molecules.

Ectopic expression of carcinoembryonic antigen (CEA) by the melanoma cell line Mel Wei led to alterations in cell morphology and to changes in the expression of two melanoma-associated cell adhesion molecules, neural cell adhesion molecule and MUC18. The normally flat, triangular cells developed neurite-like extensions and exhibited a less organized growth pattern. When compared to untransfected Mel Wei cells or to those transfected with an irrelevant cDNA, two independent CEA transfectants showed a decrease in the expression of neural cell adhesion molecule and an increase in the expression of MUC18. These changes, which are characteristic of the metastatic phenotype in melanomas, were observed at the cell surface and at the level of mRNA and were independent of adherent growth. Steady-state levels of neural cell adhesion molecule mRNA were reduced in CEA-expressing cells by approximately 5-fold, while MUC18 mRNA showed an 8-fold increase. No significant differences in the expression of intercellular adhesion molecule-1 or beta-2 microglobulin were observed between Mel Wei and CEA-Mel Wei. These data indicate that changes in the expression of a single cell adhesion molecule such as CEA can lead to alterations in the expression of unrelated cell adhesion molecules and may contribute to the general derangement of adhesive interactions observed frequently in tumor cells.