ECTOPIC EXPRESSION OF CARCINOEMBRYONIC ANTIGEN BY A MELANOMA CELL LEADS TO CHANGES IN THE TRANSCRIPTION OF 2 ADDITIONAL CELL-ADHESION MOLECULES

Ectopic expression of carcinoembryonic antigen (CEA) by the melanoma c ell 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 organize d growth pattern. When compared to untransfected Mel Wei cells or to t hose transfected with an irrelevant cDNA, two independent CEA transfec tants showed a decrease in the expression of neural cell adhesion mole cule and an increase in the expression of IL MUC18. These changes, whi ch are characteristic of the metastatic phenotype in melanomas, were o bserved at the cell surface and at the level of mRNA and were independ ent of adherent growth. Steady-state levels of neural cell adhesion mo lecule mRNA were reduced in CEA-expressing cells by approximately 5-fo ld, while MUC18 mRNA showed an 8-fold increase. No significant differe nces in the expression of intercellular adhesion molecule-1 or beta-2 microglobulin were observed between Mel Wei and CEA-Mel Wei. These dat a indicate that changes in the expression of a single cell adhesion mo lecule such as CEA can lead to alterations in the expression of unrela ted cell adhesion molecules and may contribute to the general derangem ent of adhesive interactions observed frequently in tumor cells.