Metastatic potential in nude mice of Chinese hamster ovary cells expressing human carcinoembryonic antigen.

The role of carcinoembryonic antigen (CEA) in metastasis was examined using Chinese hamster ovary (CHO) cells which had been transfected with cDNA encoding CEA. When 2 x 10(6) cells of a clone of CEA-expressing transfectants, designated CHO/CEA, were injected intrasplenically into athymic nude mice, 8 out of 8 mice developed liver metastases. In contrast, a vector-transfectant C5 did not at all form metastasis in the assay (0 of 8). There was no difference in growth rate between CHO/CEA and C5 in vivo as well as in vitro. MoAbs to N-domain of CEA markedly inhibited the liver metastasis of CHO/CEA cells, while a MoAb to domain III of the antigen did not. These findings suggest that CEA may play an important role in hepatic metastasis, and that the N-domain of CEA molecule contributes to the function of CEA in metastasis.